Category: Surgical technique

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Estimating meningioma consistency before surgery with T2-weighted MRI

Neurosurgery. 2026;99(5):1059–1067

A meningioma that yields to suction poses a different operative challenge from one that requires sharp dissection. In this series of 188 resections, tumors with lower T2 signal relative to the middle cerebellar peduncle tended to be firmer at surgery. Measuring this ratio on routine preoperative MRI offers a way to anticipate the demands of internal debulking, particularly when working close to cranial nerves or vessels.

Study and key findings

At one center, a surgeon prospectively graded tumor consistency on a five-point scale during operations performed between 2012 and 2024. For the retrospective imaging analysis, readers blinded to the operative grade sampled three representative 20 mm² regions of tumor, avoiding focal cystic change and calcification. They divided the average tumor signal by the reference signal sampled from the middle cerebellar peduncles.

The mean T2 ratio decreased from 1.98 in soft tumors to 1.71 in intermediate tumors and 1.41 in firm tumors. Diffusion measurements on apparent diffusion coefficient maps showed no significant association with consistency.

Interpretation and limitations

The mean T2 ratio distinguished the soft and firm groups with an area under the ROC curve of 0.868. That comparison excluded the 87 intermediate tumors, nearly half the cohort. For the more practical question of identifying a firm tumor among all patients, a cutoff of 1.515 yielded 75% sensitivity and 75% specificity in the internal test set.

All operations were performed by one skull base surgeon, and only 20 tumors were classified as soft in the study tables. The proposed thresholds need prospective validation at other centers. Whether planning with this measurement improves extent of resection or reduces complications remains untested.

Clinical takeaway

A low tumor-to-peduncle T2 ratio can prompt the team to prepare for mechanical debulking and sharp dissection. Interpret the estimate alongside the tumor’s relationship to adjacent nerves and vessels, and reassess the plan as its consistency and dissection planes become apparent during surgery.

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Trigeminal neuralgia: anticipating difficult arterial anatomy before decompression

Acta Neurochirurgica. 2026.  DOI: 10.1007/s00701-026-07055-3

Arterial variants can make microvascular decompression more demanding without necessarily precluding favorable outcomes. Kawano and colleagues identify the trigeminocerebellar artery as particularly relevant: its relationship to the trigeminal root may involve penetrating vessels, encircling loops or perforators that restrict mobilization. The practical message is to anticipate these configurations before surgery, rather than assume every offending artery can be displaced in the same way.

Study and key findings

This retrospective single-center study included 170 adults, aged 19-84 years, undergoing first-time microvascular decompression for drug-resistant classical trigeminal neuralgia: 172 operated sides, including two bilateral cases. Preoperative assessment combined high-resolution MR angiography, heavily T2-weighted imaging and three-dimensional reconstruction.

Among 168 patients with unilateral symptoms, the trigeminocerebellar artery was more frequent on the affected than the contralateral side: 10.7% versus 4.8% (P=.033). Early bifurcation of the superior cerebellar artery showed no significant side difference.

Of 19 operated sides with an offending trigeminocerebellar artery, four showed root penetration, four encircling loops and five multiple perforators. All four penetration configurations were identified preoperatively. Recurrence occurred in 28/172 sides overall (16.3%), including 3/19 in this subgroup (15.8%); comparisons did not demonstrate significant recurrence differences between arterial groups.

Interpretation and limitations

The technical distinction is between an artery passing between sensory and motor roots and one penetrating the sensory root itself. Transposition predominated; nerve splitting was used only in the two cases with direct sensory-root penetration. These observations do not justify routine nerve splitting or establish superiority over alternative decompression techniques.

The retrospective design, selected surgical population and small variant subgroups limit inference. Contralateral comparisons demonstrate association, not causality. MRI-based classification cannot always distinguish a trigeminocerebellar artery from a duplicated superior cerebellar artery. Nonsignificant outcome comparisons do not establish equivalent safety, particularly for uncommon neurological complications.

Clinical takeaway

Preoperative imaging should inform how the artery relates to the root and perforators, not merely identify vascular contact. This series supports anatomy-specific planning and cautious mobilization, while leaving the comparative benefits and risks of individual maneuvers unresolved.

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An intraoccipital route to the ventricular atrium: promise and anatomical trade-offs

Journal of Neurosurgery. 2026;145(4):1199-1207

The intraoccipital sulcus may provide a useful route to the ventricular atrium, but following a natural sulcus does not eliminate white matter injury. Anastasopoulos and colleagues map a roof-directed corridor whose potential advantages remain anatomical rather than clinically demonstrated. Their findings inform approach selection without establishing superior safety or preservation of visual function.

Study and key findings

The investigators examined 20 adult cadaveric hemispheres from 10 donors, supplemented by MRI assessment of 20 Human Connectome Project subjects and another 25 healthy individuals.

The anterior approximately 1.2-cm sulcal segment aligned with the atrial roof; posterior trajectories instead led toward the occipital horn. The mean MRI distance from the sulcal fundus to the atrium was 1.90 ± 0.48 cm. These descriptive measurements are not patient-specific safety margins.

Although the medial, roof-directed trajectory offers a potentially favorable relationship to lateral-wall optic radiations, the corridor disrupts the vertical occipital fasciculus and crosses the posterior sagittal stratum and tapetum. It is therefore not a white matter-free route.

Interpretation and limitations

The practical question is whether the anterior intraoccipital sulcus provides suitable exposure for a particular atrial lesion. Anterior and posterior sulcal segments are not interchangeable, and lesions extending farther anteriorly may require an unfavorable working distance. A plausible editorial implication is to weigh target geometry and intervening fiber anatomy together, rather than select the approach solely from a recognizable surface landmark.

No operative series, postoperative visual outcomes or clinical comparison with alternative approaches was included. Cadaveric tissue and illustrative template-space tractography cannot establish individual functional safety. Manual MRI measurements also lacked demonstrated interobserver reliability.

Clinical takeaway

The anterior intraoccipital sulcus deserves consideration as an anatomical option for atrial access. Its contribution is a clearer understanding of trajectory and white matter costs, not proof of a safer operation. Clinical validation remains necessary before anatomical feasibility can be translated into claims of neurological benefit.

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Vestibular schwannoma surgery: choosing the corridor around hearing, volume and anatomy

J Neurosurg 145:1128–1140, 2026

Choosing an operative corridor for vestibular schwannoma requires balancing tumor removal with hearing, facial function and the demands of safe neurovascular dissection. Erginoglu and colleagues compare single-stage retrosigmoid and translabyrinthine resections in a consistent surgical practice, examining tumor volume alongside anatomical grade. Their findings associate the translabyrinthine route with more complete removal and less postoperative edema in larger tumors, while the retrosigmoid route retains the possibility of hearing preservation. Rather than establishing a universally superior approach, the study illustrates how audiometry, internal auditory canal involvement and the tumor-brainstem relationship should inform individualized planning.

Objective

To compare resection, cranial nerve function, radiological changes and recovery after retrosigmoid (RS) and translabyrinthine (TL) surgery, and assess how preoperative tumor volume influences outcomes beyond Koos grade.

Methods

This retrospective study included 283 patients undergoing single-stage resection at one tertiary center between 2006 and 2023: 207 through TL and 76 through RS. All procedures involved one neurosurgeon and a consistent neurotology team. Previous surgery or radiotherapy, neurofibromatosis types 1 or 2, and staged, combined or alternative approaches were excluded. Follow-up was at least 12 months.

Serviceable hearing, defined by audiometric class A or B, generally favored RS; nonserviceable hearing generally favored TL. However, anatomical or audiological considerations led to deviations in approximately 30% of cases. The groups therefore differed substantially before surgery: serviceable hearing was present in 30.9% of TL and 72.4% of RS patients.

Tumor volume was estimated from three MRI diameters using a modified ellipsoid formula. Outcomes included extent of resection, House-Brackmann facial function, hearing, MRI abnormalities and modified Rankin Scale scores. Multivariable models and two separate propensity-matched analyses, each with 52 patients per approach, addressed measured baseline differences.

Main results

For Koos III-IV tumors, Table 2 reports gross-total resection in 106/125 TL cases (84.8%) versus 39/56 RS cases (69.6%). Edema occurred in 0.8% versus 30.4%, respectively. Across all grades, favorable one-year facial function among patients starting with House-Brackmann I-II was 93.9% after TL and 94.7% after RS, without significant separation. Hearing preservation occurred only after RS. Median hospitalization was five days after TL versus four after RS in both Koos strata, although rehabilitation discharge was more frequent after RS in larger tumors. Greater volume reduced the likelihood of complete resection.

Interpretation

The operative decision should integrate hearing potential with the required exposure. TL offers direct internal auditory canal access and early facial nerve identification, while sacrificing hearing; RS provides broad cerebellopontine angle exposure with a possibility of hearing preservation. The authors describe CSF release and avoidance of fixed retractors during RS, yet intermittent cerebellar manipulation remained necessary. Less manipulation is a plausible explanation for the TL edema findings, not a proven causal mechanism. Dense adherence to the facial nerve or brainstem should still limit resection rather than be overcome to achieve a radiographic endpoint.

Limitations

This was not a randomized comparison. Hearing status and anatomy actively determined the approach, and adjustment cannot eliminate confounding by indication. Single-surgeon consistency improves procedural uniformity but limits generalizability. The 18-year period also encompassed changing practice: RS use declined over time. These results do not compare surgery with observation or radiosurgery, nor do they apply directly to previously treated or staged cases.

Sparse events made several adjusted models unstable. The very large estimated association between TL and favorable discharge function had a wide confidence interval and should not be interpreted as a reliable measure of treatment effect. Multiple comparisons were performed without correction. Gliosis, unlike edema, did not remain significantly different in the matched radiological analysis. Radiological abnormalities also did not consistently correspond to persistent disability.

Reporting inconsistencies warrant caution. The abstract labels the 84.8% and 69.6% figures as combined gross-total/near-total resection, whereas Table 2 assigns them to gross-total resection alone. The reported hearing-preservation percentages use the entire RS Koos subgroups as denominators, rather than clearly restricting them to patients with serviceable preoperative hearing; they should not be presented as individualized preservation probabilities. Patient-reported quality of life and systematic headache outcomes were not collected, and the low recurrence counts do not establish long-term oncological equivalence.

Clinical takeaway

Use tumor volume alongside Koos grade, detailed audiometry and canal-brainstem anatomy to select the corridor. TL may offer useful exposure when hearing preservation is not a realistic priority; RS remains relevant when it is. This series supports tailored planning and function-limited resection, not routine TL selection for every large tumor or an expectation of shorter hospitalization.

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Surgical management of jugular foramen meningiomas: a function-prioritized perioperative workflow

Neurosurg Focus 61(3):E6, 2026

Surgery for a jugular foramen meningioma requires balancing access to several anatomical compartments against the vulnerability of the lower cranial nerves and venous outflow. An apparently satisfactory resection may still carry a substantial functional cost if swallowing or voice deteriorates. Matsushima and colleagues describe a perioperative strategy linking compartment-based exposure, selective embolization, vagus nerve monitoring and structured swallowing assessment. Their series illustrates how deliberate residual tumor can form part of a function-preserving operation, while emphasizing that avoidance of severe disability does not mean absence of postoperative symptoms.

Objective

To describe a function-prioritized surgical workflow for jugular foramen meningiomas and evaluate recovery of oral intake, swallowing and voice outcomes, extent of resection and subsequent treatment for tumor progression.

Methods

This retrospective single-center study included 26 consecutive primary resections performed between 2014 and 2025. Mean age was 45.1 years, with a range of 16–77 years; the cohort therefore was not exclusively adult. Previous surgery for the same lesion was excluded, although one patient previously treated with stereotactic radiosurgery was retained.

Twenty tumors involved the intradural and intrajugular compartments (IJ), and six also extended extracranially (IJE). Imaging assessed tumor extension, vascularity and sigmoid–jugular venous patency. Embolization was performed selectively in 16 patients, and continuous vagus nerve monitoring was implemented in 16. Outcomes included extubation timing, time to oral intake and swallowing and voice status at one year, together with resection extent and salvage treatment during follow-up.

Main results

The principal approaches were suprajugular in 13 patients, retrosigmoid in nine and transjugular transsigmoid in four. All four transjugular cases had extracranial extension and ipsilateral sigmoid–jugular occlusion, illustrating the anatomical selection underlying approach choice.

Gross-total resection was achieved in seven patients, near-total resection in ten, subtotal resection in eight and partial resection in one. Eighteen operations were classified as Simpson grade IV. Residual disease associated with subtotal or partial resection predominantly occupied the intrajugular or extracranial compartments rather than representing persistent intradural tumor bulk. All six IJE tumors underwent subtotal or partial resection.

All patients were extubated immediately after surgery. Twenty resumed oral intake within seven days, five between days eight and fourteen, and one after fourteen days. At one year, swallowing remained worse than baseline in 14 patients (54%) and voice in 12 (46%). Almost all worsening was mild; one patient had moderate impairment of both functions. No patient required tracheostomy, gastrostomy, long-term tube-feeding dependence or phonosurgical intervention. One surgical site infection required bone flap removal, and one CSF leak was managed with lumbar drainage.

All six patients with IJE tumors reported persistent worsening of swallowing and voice, compared with 40% and 30%, respectively, in the IJ group. Median time to oral intake was eight versus two days. These differences should be interpreted in the context of larger tumors, more baseline dysfunction and different operative exposures in the IJE subgroup.

Among monitored patients, lower preservation of vagus response amplitude was associated with worse swallowing at one year in an exploratory analysis. The most symptomatic patient experienced an abrupt decline to zero. During a median follow-up of 55.6 months, three patients underwent salvage radiosurgery for progression. No patient received routine planned adjuvant radiosurgery after limited resection.

Interpretation – operative relevance

The operative corridor was chosen to expose the involved compartments while accounting for venous function. A retrosigmoid approach served predominantly intradural lesions. When additional intrajugular access was necessary, an intradural suprajugular extension allowed drilling of the jugular foramen roof while preserving the sigmoid–jugular venous system. This distinction is useful when intraforaminal exposure is required but functioning venous drainage should be maintained.

For selected extensive IJE tumors with an occluded ipsilateral venous system, the transjugular transsigmoid approach combined posterior mastoidectomy with high cervical exposure. The reported technique included ligation and division of the exposed sigmoid–jugular system to obtain access to the intrajugular and extracranial disease. This describes a strategy used in four anatomically selected cases; it is not evidence that venous sacrifice is generally safe or that an imaging finding of occlusion alone establishes expendability.

Continuous vagus monitoring complemented intermittent nerve mapping. The authors used repetitive direct stimulation at 1 Hz and compared the final evoked amplitude with baseline. Their practical response to declining or unstable signals was to reassess traction, coagulation and dissection planes, accepting residual tumor when further dissection threatened function. The study does not validate a universal amplitude threshold for stopping resection or prove that monitoring independently improves outcomes.

The location of residual tumor is as important as the overall resection category. Deliberately retaining adherent intrajugular, extracranial or paracarotid disease may preserve function after substantial intradural clearance. Reporting both compartmental residual and resection extent is therefore more informative than interpreting Simpson grade IV as a uniform measure of operative inadequacy.

Functional preservation also extended beyond tumor removal. Intraoperative findings and monitoring changes were communicated to anesthesia, while laryngoscopic and swallowing assessment guided oral intake and diet progression. Immediate extubation in this series should be understood within that individualized multidisciplinary workflow, not as a mandatory postoperative target.

Limitations

This is a small retrospective series without a comparator. Approach, embolization and monitoring were selected according to anatomy and clinical judgment, so their individual effects cannot be separated. The extracranial-extension subgroup comprised only six patients and had shorter follow-up, limiting conclusions about durable tumor control. Swallowing and voice were assessed with clinical severity categories rather than comprehensive patient-reported instruments. The age range includes an adolescent, and aggregate outcomes cannot be treated as exclusively adult results. The association between monitoring amplitude and swallowing is exploratory rather than a validated predictive rule.

Clinical takeaway

Use compartmental extension and functional venous anatomy to plan exposure, and let the lower cranial nerve interface define the safe boundary of resection. Monitoring can inform reassessment during dissection, while deliberate residual disease requires a documented surveillance and salvage strategy. The central achievement in this series was avoidance of severe dependency, not elimination of swallowing and voice morbidity—a distinction that belongs in both surgical planning and patient counseling.

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Comparative outcomes of syringopleural, syringosubarachnoid, and syringoperitoneal shunts for syringomyelia: a single-center retrospective cohort study

J Neurosurg 145:831–842, 2026

When symptomatic syringomyelia persists despite treatment of its underlying cause, choosing a drainage route requires more than selecting the shortest catheter trajectory. The condition of the subarachnoid space, the level of the cavity and the suitability of an extracranial receiving compartment all influence the operation and its subsequent failure modes. Khalafallah and colleagues compare three shunting strategies in a small adult cohort, illustrating the tension between early decompression and durable neurological benefit. Their findings support individualized planning and careful surveillance, rather than a universal hierarchy of shunt types.

Objective

To compare revision burden, time to failure and neurological outcomes after syringopleural, syringosubarachnoid and syringoperitoneal shunting for syringomyelia.

Methods

The authors retrospectively reviewed a prospectively maintained single-surgeon database covering 1997–2025. Thirty-one adults aged at least 18 years underwent 48 procedures: 20 syringopleural, 21 syringosubarachnoid and seven syringoperitoneal operations. Mean patient age was 47.2 years. Underlying conditions included trauma, tethering, meningitis and Chiari I malformation, as well as cases without an identified cause.

Shunt selection was determined by anatomy, presumed drainage physiology, previous operations and comorbidity, rather than random allocation. Four patients received different shunt types during their treatment and contributed to more than one group. Neurological status was classified as improved, unchanged or worse immediately after surgery, at three months and at the last available follow-up. Revision meant returning to the operating room for a shunt-related complication.

Main results

Ten of 31 patients required at least one revision; revision procedures accounted for 17 of the 48 operations. The reported revision proportions were 11/20 for syringopleural, 4/21 for syringosubarachnoid and 2/7 for syringoperitoneal procedures (55.0%, 19.0% and 28.6%; reported p = 0.003). These figures describe a dataset containing repeated operations and overlapping patient groups: they should not be interpreted as independent patient-level probabilities of failure after an initial shunt.

Catheter migration accounted for four of the 11 syringopleural revisions. Other revision indications included recurrent syrinx, obstruction, traumatic injury, subdural hygroma and infection. Neither time to revision nor the patient- or shunt-based revision-free survival comparisons showed a statistically significant difference between groups.

Immediate neurological improvement occurred after 11/20 syringopleural, 7/21 syringosubarachnoid and 1/7 syringoperitoneal procedures. Although numerically highest in the pleural group, the difference was not statistically significant (p = 0.117). At three months, improvement was recorded in 7/16, 6/13 and 2/6 evaluable cases, respectively, again without a significant difference.

Long-term observations were less reassuring but substantially incomplete. At the last assessment, improvement was recorded in one of ten evaluable pleural cases, two of ten subarachnoid cases and none of four peritoneal cases. Approximately half the clinical observations were missing in each group, and imaging completeness was even lower. These results raise concerns about durability but cannot establish the true frequency of late deterioration in the entire cohort.

Interpretation – operative relevance

The first decision is whether a shunt is appropriate at all. The authors place correction of the underlying pathology—such as craniocervical obstruction or tethering—before direct syrinx diversion when such treatment is feasible. Their comparison therefore informs drainage selection in selected refractory cases, not the replacement of cause-directed surgery by routine shunting.

For destination selection, their practice generally favored pleural drainage for cervical or upper thoracic cavities and peritoneal drainage for lower thoracic cavities. These preferences reflected anatomical access and presumed drainage characteristics, not proven superiority at particular spinal levels. Previous chest or abdominal surgery, pulmonary disease, peritonitis and earlier shunt failure also influenced the choice.

The subarachnoid option depended particularly on the receiving space. The authors increasingly restricted it to preserved subarachnoid anatomy or focal, single-level adhesions, avoiding reliance on a severely scarred or functionally obstructed compartment. Their practical message is to assess where fluid can drain effectively, rather than choosing a local shunt solely because it avoids a distal extracranial catheter.

The operative description includes laminectomy, intraoperative ultrasound localization, midline durotomy and myelotomy, and placement of a nonvalved silicone catheter. Pleural and peritoneal systems required subcutaneous tunneling to the selected destination; dural closure around the catheter was made watertight using sutures with sealant and/or graft material. These are the techniques used in the series, not independently tested determinants of outcome.

The observed pleural migrations make catheter stability an important planning concern. However, this study does not compare fixation techniques or establish a superior anchoring method. During revision, the authors considered changing the distal compartment when fibrosis, scarring or impaired absorption was suspected. Finally, early reduction in syrinx size should be interpreted alongside neurological examination: radiographic decompression did not consistently translate into sustained functional recovery.

Limitations

The retrospective, single-surgeon design, small and unequal groups, heterogeneous etiologies and anatomy-driven allocation prevent causal comparisons. Practice evolved over nearly three decades, introducing additional temporal confounding. Repeated procedures and crossover between shunt types complicate the interpretation of group statistics. Neurological outcomes were qualitative, follow-up duration varied and substantial missing clinical and imaging data create a serious risk of attrition bias. In particular, patients returning because of deterioration may be overrepresented among late observations. Seven peritoneal procedures are insufficient to establish that this destination is intrinsically inferior.

Clinical takeaway

When syrinx diversion is justified, match the destination to the spinal level, subarachnoid patency and suitability of the pleural or peritoneal compartment. Plan for mechanical failure and possible revision, and assess success through sustained neurological function rather than early cavity collapse alone. This series offers useful operative considerations, but does not identify a universally preferable shunt.

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Third Ventricular Cavernous Malformations: Approach Selection for Minimally Invasive Resection and Systematic Review

Operative Neurosurgery 31:399–409, 2026

Third-ventricular cavernous malformations are rare lesions in an unforgiving anatomical corridor. This paper combines three institutional operations with a systematic review to examine how lesion position should guide the route of access. Two patients underwent endoscope-assisted supraorbital trans–lamina terminalis resection and one a port-based transsulcal exoscopic procedure. In the literature, transcallosal and transcortical transventricular craniotomies remained the most commonly reported routes. The main message is not that one minimally invasive approach is universally preferable, but that the shortest safe trajectory must be individualized around the fornices, hypothalamus, thalamus, deep veins and ventricular anatomy.

Objective

To describe minimally invasive surgical strategies for symptomatic third-ventricular cavernous malformations and synthesize the published experience to support anatomical approach selection.

Methods

The investigators reviewed a prospectively maintained institutional database and identified three symptomatic patients with imaging evidence of hemorrhage. Demographic, clinical, anatomical and surgical outcome data were analyzed. A PRISMA-based PubMed and Embase search identified the available reports of surgically treated third-ventricular cavernous malformations and the approaches used.

Main results

The institutional group included two men and one woman; all were symptomatic, none had hydrocephalus and all had signs of intralesional hemorrhage. Two lesions were removed through a supraorbital keyhole, endoscope-assisted trans–lamina terminalis route. The third was treated through a right frontal keyhole with a port-based transsulcal, exoscope-assisted route.

The review assembled 54 reported surgical cases. The most frequent routes were interhemispheric transcallosal in 26 cases (48.1%) and transcortical transventricular in 16 (29.6%). The combined experience demonstrates substantial heterogeneity in lesion origin, ventricular size and surface presentation, all of which alter the safest corridor.

Interpretation

“Minimally invasive” should describe limited tissue disruption, not merely a smaller opening. A trans–lamina terminalis route may suit an anterior or inferior lesion with favorable line of sight, whereas a transsulcal or transventricular route may better address a superior or lateral target. High-quality multiplanar and susceptibility imaging, neuronavigation and planned conversion options are more important than allegiance to a single approach.

Limitations

The institutional experience contains only three patients. The systematic review is dominated by case reports and small series, with publication bias, incomplete outcome reporting and no valid comparative groups. Some historical cases predate modern endoscopy, exoscopy, tract-informed planning and contemporary postoperative imaging.

Clinical takeaway

Select the route from the lesion’s precise relationship to the ventricular walls, foramina, fornices, hypothalamus, thalamus and deep venous structures. Use the corridor that offers direct visualization with the least neural transgression, and counsel patients that the evidence for approach superiority remains low level.

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Comparative Outcomes of Frontal, Bifrontal, and Pterional Craniotomies for Resection of Large Anterior Skull Base Meningiomas

Operative Neurosurgery 31:484–494, 2026

Large anterior skull-base meningiomas can be approached through unilateral frontal, bifrontal or pterional craniotomies, but anatomy and case complexity strongly influence that choice. This retrospective series compares the three exposures and uses propensity matching to reduce baseline imbalance. Bifrontal procedures had more medical and surgical complications and poorer cosmetic results after matching. Frontal procedures showed shorter progression-free survival, with subtotal resection emerging as an adverse predictor. The findings help frame approach selection but do not establish that one craniotomy is intrinsically superior for every tumor.

Objective

To compare outcomes after frontal, bifrontal and pterional craniotomy for large anterior skull-base meningiomas and identify approach-specific predictors of complications and tumor control.

Methods

The study retrospectively included 337 adults operated at one institution between 2010 and 2024, each with at least 1 year of follow-up. Eighty patients underwent bifrontal, 189 frontal and 68 pterional craniotomy. Propensity-score matching balanced groups for tumor size, grade and preoperative Karnofsky Performance Status. Complications, cosmetic outcomes and progression-free survival were then compared.

Main results

Before matching, patients selected for bifrontal surgery had larger tumors and lower functional status, whereas the frontal group had higher-grade tumors. After matching, medical complications occurred in 25.0% and surgical complications in 22.5% of the bifrontal group, both significantly more often than in the other groups. Unsatisfactory cosmetic outcomes were also more frequent after bifrontal surgery (6.25%).

Kaplan-Meier analysis showed more minor complications after bifrontal craniotomy and shorter progression-free survival in the frontal group. Olfactory-groove location predicted poorer outcomes in the pterional cohort, while subtotal resection predicted poorer outcome in the frontal cohort.

Interpretation

The bilateral exposure carries a morbidity cost even after adjustment for several markers of complexity. However, approach is inseparable from anatomy: midline extension, vascular encasement, optic involvement, surgeon experience and the probability of safe complete resection must shape the decision. A unilateral route should not be selected merely to avoid the statistical risk associated with bifrontal surgery.

Limitations

The retrospective single-center design is vulnerable to selection bias and changing surgical practice over 14 years. Matching addressed only measured variables and could not balance all anatomical features. The abstract does not provide adjusted effect sizes for every comparison, and the broad category of anterior skull-base meningioma combines distinct origins and operative challenges.

Clinical takeaway

Use the least disruptive exposure that still provides safe control of the tumor, neurovascular structures and dural attachment. Reserve a bifrontal route for anatomy that genuinely requires bilateral access, and counsel those patients about its higher observed medical, surgical and cosmetic complication burden.

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Maximum safe resection of insular gliomas: update on surgical outcomes from 500 cases

J Neurosurg 145:347–363, 2026

Insular gliomas remain among the most demanding intrinsic brain tumors because eloquent cortical and subcortical networks coexist with critical middle cerebral and lenticulostriate vessels. This large single-center experience evaluates whether a transcortical, mapping-guided strategy can achieve meaningful cytoreduction without unacceptable neurological morbidity. The series comprises 502 operations in 394 patients with newly diagnosed or recurrent low- and high-grade tumors. Greater extent of resection and smaller residual volumes were associated with longer survival, while persistent deficits were uncommon. The results support maximum safe resection, but also underline that oncological benefit depends on preserving neurological function.

Objective

To determine whether transcortical resection supported by cortical and subcortical mapping remains a safe and effective strategy for newly diagnosed and recurrent insular gliomas, and to examine the relationships among tumor characteristics, extent of resection, postoperative morbidity, progression-free survival and overall survival.

Methods

This retrospective single-center study analyzed 502 resections performed in 394 patients between September 1997 and December 2022. The cohort included 316 newly diagnosed tumors—165 low-grade and 151 high-grade—and 186 recurrent tumors—69 low-grade and 117 high-grade.

Tumors were classified according to the Berger-Sanai zones. Preoperative and postoperative contrast-enhancing and non–contrast-enhancing volumes were manually segmented on MRI to calculate extent of resection and residual volume. Neurological status was assessed preoperatively, immediately after surgery, at discharge, at 3 months and at least 6 months postoperatively.

The transcortical approach was adapted to hemispheric dominance and tumor anatomy. Dominant-hemisphere lesions underwent awake language and motor mapping; nondominant lesions were generally treated asleep with triple-modality motor mapping. Subcortical stimulation defined functional white-matter boundaries, while the lenticulostriate arteries marked the medial resection limit.

Progression-free and overall survival were studied using Kaplan-Meier and Cox regression analyses. Propensity-score weighting adjusted survival comparisons for factors including age, preoperative Karnofsky Performance Status and adjuvant temozolomide or radiotherapy.

Main results

Median extent of resection exceeded 80% across the analyzed molecular subtypes in both newly diagnosed and recurrent tumors. Grade 2 tumors were larger than grade 4 IDH-wildtype glioblastomas at presentation (43 versus 17.5 cm³; p<0.001), while their median residual volume was also greater (6.8 versus 0.5 cm³; p<0.001).

Among newly diagnosed grade 2 tumors, transient motor and language deficits occurred in 9.5% and 20% of cases, respectively. Persistent deficits were substantially less frequent: 0.6% for motor function and 3.3% for language. Across all 502 operations, only 3 patients (0.59%) had permanent hemiparesis below antigravity strength. Surgical and medical complications each occurred in fewer than 3% of cases, and more than 94% of patients were discharged home.

For newly diagnosed IDH-mutant grade 2 tumors, residual non–contrast-enhancing volume below 2.7 cm³ was associated with longer overall survival, while a residual volume below 4.3 cm³ was associated with longer progression-free survival. In recurrent grade 2 tumors, residual volumes below 0.8 cm³ and 1.8 cm³ were associated with improved overall and progression-free survival, respectively.

For newly diagnosed IDH-wildtype glioblastoma, resection of more than 88.6% of the contrast-enhancing component was associated with longer overall survival, and resection above 87.08% with longer progression-free survival. Median overall survival was 18.5 months when contrast-enhancing extent of resection exceeded 88.6%.

A new permanent arm or leg deficit was independently associated with worse overall survival (HR 2.06; 95% CI 1.14–3.74; p=0.017).

Interpretation

The study provides strong observational support for a transcortical, mapping-guided approach to insular glioma surgery. Meaningful cytoreduction was achievable across all Berger-Sanai zones and in both initial and repeat operations, with a low frequency of permanent neurological morbidity.

The survival analyses also refine the concept of “maximum safe resection.” Benefit was associated not only with percentage resection but with the absolute residual volume, particularly in IDH-mutant grade 2 glioma. Nevertheless, these thresholds should be interpreted as cohort-derived prognostic markers rather than mandatory surgical targets.

The association between permanent weakness and poorer survival is clinically crucial. It indicates that aggressive cytoreduction loses part of its oncological value when it produces lasting neurological injury. Functional preservation is therefore an integral component of oncological efficacy, not merely a secondary safety endpoint.

Limitations

This was a retrospective experience from a single, highly specialized center, which limits generalizability to teams with different mapping expertise or operative volumes. The 25-year inclusion period encompassed major changes in imaging, mapping, neuropathological classification and adjuvant treatment.

Molecular information was incomplete in earlier cases; survival analyses were consequently restricted to tumors that could be classified according to the 2021 WHO framework. Treatment selection was not randomized, and residual confounding remains despite propensity-score adjustment. The study does not directly compare transcortical surgery with transsylvian resection, biopsy, laser interstitial thermal therapy or IDH-inhibitor-based strategies.

The reported residual-volume and extent-of-resection cutoffs were derived retrospectively from this cohort and require external validation. Detailed neurocognitive and quality-of-life outcomes were also less comprehensive than the motor and language assessments.

Clinical takeaway

Maximum safe resection should remain the operative goal for appropriately selected adult patients with insular glioma, including selected recurrent tumors. A transcortical approach supported by individualized cortical and subcortical mapping can produce substantial cytoreduction with low permanent morbidity in experienced hands.

The surgeon should prioritize the smallest safely achievable residual volume rather than pursue a percentage target at the expense of functional pathways or lenticulostriate vessels. In practical terms, the oncological objective and the functional boundary are inseparable: avoid a permanent deficit, because neurological injury is itself associated with poorer survival.

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Relationships Between Surgical Approach, Tumor Classification Scheme, and Early Neurocognitive Outcome After Awake Craniotomy for Resection of Insular Glioma

Operative Neurosurgery 30:880–889, 2026

This study evaluates early postoperative neurocognitive outcomes after awake craniotomy for insular glioma resection, comparing transcortical and transsylvian approaches and examining tumor classification schemes. It reports frequent, domain-specific declines—most notably in memory and verbal fluency—and analyzes relationships with tumor hemisphere, insular zone, and extension.

The authors found similar overall neurocognitive change across surgical corridors but identified higher verbal fluency decline with transcortical approaches and greater domain-specific risk linked to left-sided tumors, extra-insular extension, and anterior or inferior insular involvement.

Study aim: Assessed how surgical approach (transsylvian vs transcortical) and tumor classification/location relate to early postoperative neurocognitive function (NCF) after awake resection of insular glioma.

Cohort & design: Retrospective series of 53 newly diagnosed insular glioma patients (47% high-grade; 75% left hemisphere) treated with awake craniotomy, with neuropsychological testing pre-op and within 60 days post-op.

Classification schemes: Tumors were categorized by Berger–Sanai zones (collapsed to anterior/posterior/superior/inferior) and Pitskhelauri extension groups (insula only; insula + extension; predominantly extra-insular).

Overall NCF change: Postoperative decline occurred across multiple domains, with the largest effects most often in memory and verbal fluency (executive function).

Frequency of clinically meaningful decline: 85% declined on ≥1 test (Δz ≤ −1.0), 52% on ≥2 tests, and 22% on ≥5 tests; decline was most frequent/severe in memory and also common in executive function, attention, and processing speed.

Surgical approach comparison: Mean NCF change generally did not differ by approach, but the transcortical approach showed a higher rate of verbal fluency decline than transsylvian (61% vs 26%).

Tumor hemisphere & localization effects: Left-hemisphere tumors were linked to poorer outcomes on multiple tests (notably memory, verbal fluency, naming, and token comprehension), while anterior tumors had worse executive function (mental flexibility) than posterior, and inferior lesions had worse recognition memory than superior.

Tumor extent/size associations: Predominantly extra-insular tumors had greater fluency reduction than insula-only; more Berger–Sanai quadrants involved correlated with worse executive function change; larger tumor volume and higher postoperative FLAIR volume related to worse processing speed and comprehension outcomes.

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The posterior approach for removal of all thoracic disc herniations

J Neurosurg Spine 44:876–883, 2026

his single-surgeon series evaluates a posterior partial transpedicular approach for symptomatic thoracic disc herniation augmented by intraoperative ultrasound (IOUS) and ultrasonic aspiration (UA). Over 108 patients (137 discs) treated from 2012–2024, the technique produced significant neurological improvement with an acceptable complication and reoperation profile.

The report details patient selection, operative steps, radiographic grading, neuromonitoring use, outcomes (Frankel grade improvements), and multivariate predictors, highlighting the method’s versatility for giant and calcified herniations and its accessibility to general spine surgeons.

Clinical problem Thoracic disc herniation is surgically challenging due to ventral location, frequent calcification, and risk of severe neurologic compromise; anterior/lateral approaches can be effective but carry substantial morbidity and technical demands.

Study aim Evaluated safety, efficacy, and versatility of a posterior partial transpedicular discectomy augmented with intraoperative ultrasound (IOUS) and ultrasonic aspiration (UA) for symptomatic TDH.

Cohort & design Retrospective single-surgeon series of 108 consecutive patients (137 TDHs) treated from 2012–2024; outcomes tracked with Frankel grades preop, 3–6 months, and final follow-up; multivariate regression used to identify predictors of improvement.

Key technique Posterior midline exposure with laminectomy, <50% medial facetectomy, and superomedial caudal pedicle removal using UA to create a corridor; IOUS used after laminectomy, during ventral work, and after resection to confirm decompression and detect residual/migrated fragments; IONM used in all cases.

Case mix severity Most patients presented with myelopathy (86.1%); many discs were giant (>40% stenosis, 68.6%) and frequently calcified (complete 38.7%, incomplete 21.2%).

Neurologic outcomes Mean Frankel grade improved from 3.77 preop to 4.54 at last follow-up (p < 0.001); 61.1% improved by ≥1 Frankel grade; follow-up for the primary outcome was 100%.

Safety & complications IOUS and UA enabled safe decompression in all cases; reoperation-requiring complications occurred in 9.3% (most commonly reherniation 4.6%); no postoperative CSF leaks through the wound were reported.

Predictors & conclusion Less neurologic improvement was associated with diabetes and obesity (and heart disease); overall conclusion: posterior partial transpedicular approach with IOUS and UA is safe, effective, and broadly applicable for TDH (including large/calcified lesions) and can be adopted by general spine surgeons.

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History and evolution of the far‑lateral approach in neurosurgery

Acta Neurochirurgica (2026) 168:122

This review chronicles the development and technical refinement of the far‑lateral approach (FLA) for accessing the foramen magnum, lower clivus, and craniovertebral junction, tracing its origins from lateral suboccipital exposures to contemporary transcondylar, supracondylar, paracondylar, and extreme lateral transodontoid variants. It summarizes modifications in skin incisions, bony resection strategies, VA management, positioning, and closure techniques that improved exposure while minimizing brain retraction and craniovertebral morbidity.

The article evaluates clinical outcomes, biomechanical data, and technological integrations—endoscopic assistance, neuronavigation, and neuromonitoring—emphasizing a tailored, pathology-driven philosophy: remove only the bone necessary, mobilize the vertebral artery judiciously, and consider occipitocervical fusion when stability thresholds are exceeded to balance maximal resection with minimal long‑term instability and CSF complications.

Purpose: Provides a more anterior, tangential corridor to the foramen magnum/lower clivus/CVJ for ventrolateral or anterior brainstem pathology, reducing the need for brainstem/cerebellar retraction compared with older midline posterior and transoral routes.

Origins: Evolved from posterolateral aneurysm surgery—early unilateral suboccipital routes in the 1970s, with the first detailed “lateral suboccipital” (far-lateral) description by Heros in 1986 to reach distal vertebral and basilar trunk aneurysms by extending bone removal to the lateral foramen magnum rim.

Key bone-work concept: The major exposure-expanding step is selective occipital condyle drilling (transcondylar variant), typically about one-third to one-half to improve the angle of attack while aiming to preserve craniocervical stability; complete condyle removal is rare and generally prompts fusion.

Modular variants: The approach is used as adjustable “modules,” most notably transcondylar, supracondylar (jugular tubercle drilling), and paracondylar extensions, chosen based on lesion location and direction of extension.

Soft-tissue refinements: Incisions shifted from simple linear cuts to more tailored curvilinear/hockey-stick/C-shaped designs with larger musculocutaneous flaps to improve exposure, enable layered closure, and reduce wound/CSF-leak complications.

Positioning evolution: Use moved away from sitting (air embolism risk) toward lateral/modified park-bench positioning to leverage gravity-assisted relaxation and minimize fixed retraction.

Neurovascular strategy: Standardization of extradural vertebral artery (V3/V4) exposure and mobilization (when needed) improved proximal control and widened the corridor, turning the artery from an obstacle into a structure that can be safely managed to expand working space.

Modern extensions & technology: Continued refinement includes endoscope-assisted visualization, neuronavigation, and neuromonitoring; an extreme extension (ELTO) adds aggressive bony removal (including odontoid/C1 elements) for midline-crossing lesions but carries high instability risk, so occipitocervical fusion is typically performed.

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The utility of partial sensory rhizotomy and adjunct procedures in the surgical management of trigeminal neuralgia secondary to multiple sclerosis

J Neurosurg 144:1145–1153, 2026

This clinical study evaluates long-term outcomes of partial sensory rhizotomy (PSR) for trigeminal neuralgia (TN) secondary to multiple sclerosis (MS), comparing PSR alone, redo PSR, and PSR combined with microvascular decompression (MVD) or internal neurolysis (IN). Retrospective analysis of 37 procedures in 30 patients shows high immediate pain relief (89.2%), mean recurrence at 1.64 years, and variable durability across groups.

At final follow-up, combination therapy (PSR+MVD or PSR+IN) trended toward superior sustained pain freedom without increased complications, while first PSR commonly required additional interventions. The authors conclude PSR is an effective salvage option and suggest adjunctive MVD or IN may improve long-term outcomes, recommending prospective validation.

Objective Evaluate long-term outcomes of partial sensory rhizotomy (PSR) alone versus PSR combined with microvascular decompression (MVD) or internal neurolysis (IN) for trigeminal neuralgia secondary to multiple sclerosis.

Methods Retrospective review of PSR cases (2012–2023) grouped as first PSR, redo PSR, PSR+MVD, and PSR+IN; assessed pain outcomes, recurrence, and complications.

Cohort 30 patients underwent 37 procedures; 89.2% of procedures followed at least one prior ipsilateral TN procedure.

Immediate outcomes 89.2% achieved immediate postoperative pain relief (pain free with or without medication), with no significant differences between procedure groups.

Durability Pain recurred on average at 1.64 ± 1.71 years after the procedure, with no significant differences among groups.

Final follow-up pain freedom At mean 3.14 ± 2.58 years follow-up, 75% of PSR+MVD and 100% of PSR+IN cases were pain free; 52.3% of first PSR cases required additional procedures.

Complications Overall complication rate was 29.7% with no significant differences between groups; ipsilateral facial numbness was common (59.5%) and treated as an expected outcome rather than a complication.

Conclusion PSR functions effectively as a salvage option for MS-related TN, and adding MVD or IN may improve long-term pain relief without increasing complication rates.

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Addressing Temporal Muscle Atrophy and Enhancing Cranioplasty Outcome

Operative Neurosurgery 30:588–594, 2026

This multicenter prospective study evaluates a dual-layer dural substitute technique during decompressive craniectomy to prevent adhesions between the temporalis muscle and dura, thereby improving subsequent cranioplasty outcomes. Across 59 patients, the method reduced adhesions, preserved temporalis muscle thickness, shortened cranioplasty operative time, minimized blood loss, and eliminated postoperative cranioplasty-related seizures.

The paper details surgical steps, material selection (Neuro-Patch), intraoperative placement of two dural layers, and cranioplasty retrieval of the superficial patch to restore muscle function. Results show improved wound healing metrics, shorter hospital stays, and a low complication profile, while noting limitations including lack of a control group and nonstandardized long-term follow-up.

Problem: After decompressive craniectomy (DC), adhesions commonly form between the temporalis muscle (TM), dura, and brain surface, making later cranioplasty (CP) dissection difficult and increasing risks such as TM injury/atrophy and poor cosmetic outcome.

Technique: During DC, place a dual-layer dural substitute—a large patch for duraplasty plus a second patch beneath the TM (and sometimes an additional patch between TM and subcutaneous tissue)—to preserve a separable plane for future CP.

CP approach: During CP, reopen the prior incision and elevate the musculocutaneous flap between the two Neuro-Patch layers, then remove the patch under the TM and reposition the TM anatomically over the implant.

Study design: Three-year prospective multicenter series of 59 patients undergoing DC then CP; outcomes included adhesion formation, ease of dissection, TM thickness (CT-based), operative time, blood loss, and postoperative events.

Adhesion/TM preservation results: TM elevation during CP was consistently facilitated with nearly absent fibrotic adhesion, and TM thickness remained essentially unchanged pre- vs postoperatively (median 5.6 mm vs 5.5 mm).

Operative metrics: Median CP operative time was 66 minutes vs a previously estimated 105 minutes in centers not using the technique; mean blood loss was 24 mL.

Safety/complications: No reported infections, wound dehiscence, or CSF leak after DC and CP; 0% post-CP new-onset seizures in this cohort.

Conclusion: Dual-layer dural substitute placement during DC can prevent adhesions and improve subsequent CP by facilitating TM elevation, reducing operative time and blood loss, preserving TM integrity, and potentially lowering post-CP epilepsy rates.

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Simple Microvascular Decompression for Hemifacial Spasm Caused by Dolichoectatic Vertebral Artery

Operative Neurosurgery 30:606–609, 2026

This operative case report describes a straightforward microvascular decompression (MVD) technique for hemifacial spasm (HFS) caused by a dolichoectatic vertebral artery (VA), emphasizing translocation and padding of the root entry zone (REZ) with Teflon pledgets. The 67-year-old patient underwent retrosigmoid craniotomy with safe mobilization of the VA, achieving immediate and sustained symptom resolution despite residual distal contact.

The authors compare REZ-focused decompression to more complex options such as sling transposition and binder-ring bypass, arguing that limited REZ decompression offers a simpler, lower-risk solution when complete arterial mobilization is unfeasible. Operative nuances, monitoring, outcomes, and literature context are provided to support this effective, pragmatic approach.

Condition Hemifacial spasm can be caused by neurovascular compression of the facial nerve at the root entry zone (REZ), and a tortuous/dolichoectatic vertebral artery (VA) is a rare culprit that makes complete decompression challenging.

Standard MVD outcomes Typical microvascular decompression for HFS (usually targeting AICA/PICA) provides >90% symptomatic relief at 1-year follow-up with notable complications including hearing loss (2.3%) and facial palsy (0.9%).

Limitations of sling transposition Macrovascular decompression with a Teflon/Gore-Tex sling can be effective but may be infeasible when anchoring is poor or when artery manipulation risks kinking/disrupted blood flow or distal nerve stretching.

Higher-complexity alternative The “binder ring” approach (VA transection, relocation, and reanastomosis) is described but is lengthy, requires temporary occlusion, and carries elevated risk (e.g., brainstem/cerebellar infarct).

Case presentation A 67-year-old woman with debilitating left HFS had a large tortuous VA abutting the facial nerve REZ; after retrosigmoid craniotomy, mobilization relieved REZ compression but residual distal cisternal contact persisted.

Key technique Simple REZ-focused decompression was achieved by mobilizing the VA as safely feasible and placing Teflon pledgets to pad the vessel away from the REZ; complete distal nerve decompression was not feasible and further manipulation was avoided due to risk to perforators/7th–8th nerve complex.

Outcome Despite residual cisternal segment contact, symptoms resolved immediately post-op and remained absent at 12-month follow-up after REZ decompression alone.

Core conclusion Targeting decompression of the REZ alone can be a simple, effective strategy for HFS due to dolichoectatic VA, potentially avoiding more complex and riskier techniques when full nerve-complex decompression is not achievable.

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Historical evolution of microvascular decompression after Jannetta’s establishment: Anatomical maps and physiological compasses—a narrative review

Acta Neurochirurgica (2026) 168:74

This narrative review chronicles five decades of refinement in microvascular decompression (MVD) for trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia, tracing developments from Jannetta’s microsurgical breakthrough to contemporary practice. It emphasizes evolving microsurgical anatomy, tailored craniotomies, endoscopic/exoscopic visualization, and nuanced decompression techniques such as noncompressive transposition versus prosthetic interposition.

The article also highlights operative support advances—high-resolution MRI/MRA, virtual simulation, and intraoperative neuromonitoring (BAEP, LSR)—as physiological “compasses” that improve safety and outcome durability. Together, anatomical “maps” and physiological feedback frame current standards and ongoing challenges in achieving long-term, biologically harmonious decompression.

Microvascular Decompression (MVD) Evolution: MVD has developed from Jannetta’s original microsurgical demonstration of vascular compression into a safe, durable, and standardized surgical treatment for neurovascular compression syndromes, especially trigeminal neuralgia (TN), hemifacial spasm (HFS), and glossopharyngeal neuralgia (GPN).

Anatomical Foundations: Detailed microsurgical anatomy, including the “Rule of Three” for the cerebellopontine angle (CPA), enables tailored, minimally invasive approaches and underpins the understanding of neurovascular conflicts and surgical route selection.

Tailored Surgical Approaches: Three individualized approaches—lateral supracerebellar-infratentorial for TN, infrafloccular for HFS, and transcondylar fossa for GPN—minimize cerebellar retraction and optimize decompression, improving safety and efficacy.

Decompression Strategies: Techniques have shifted from prosthetic interposition (placing a material between vessel and nerve) to noncompressive transposition (mobilizing and securing the vessel away from the nerve), with evidence supporting better long-term outcomes for transposition.

Visualization and Simulation Advances: The integration of endoscopic/exoscopic systems, neuronavigation, and virtual simulation has enhanced visualization, surgical precision, and education, extending the original ethos of microscopic surgery.

Intraoperative Monitoring: Real-time monitoring using brainstem auditory evoked potentials (BAEPs) and lateral spread response (LSR) on facial EMG helps avoid complications and assess decompression adequacy, significantly reducing postoperative morbidity.

Role of Imaging: High-resolution MRI and MRA now routinely identify neurovascular compression preoperatively, though imaging findings are considered supportive rather than diagnostic due to limited specificity in low-grade conflicts.

Sustained First-Line Role: Despite advances in radiosurgery and pharmacotherapy, MVD remains the first-line surgical option for appropriately selected patients, due to its proven long-term efficacy and safety.

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Three-dimensional microsurgical anatomy of the basal aspect of the cerebrum: a fiber dissection study

J Neurosurg 144:690–702, 2026

This study presents a three-dimensional microsurgical fiber-dissection analysis of the basal aspect of the human cerebrum, detailing the spatial organization of commissural, projection, and association fibers and their relationships with subcortical nuclei, ventricles, and cortical landmarks. Using 10 formalin-fixed brains with layer-by-layer dissection and stereoscopic photography, the authors map tracts such as the ILF, UF, SS, cingulum, fornix, and connections around the amygdala and nucleus accumbens.

The findings emphasize surgical implications by clarifying trajectories and landmarks relevant to approaches like STIO and SCTT, illustrating a clinical case of hippocampal glioma resection with optic-radiation preservation, and proposing that 3D anatomical insight enhances safe, precise planning for medial temporal and basal lesions.

Objective Limited surgical exposure of the cerebral base makes basal fiber-tract injury a key risk; detailed 3D tract anatomy is needed to plan safer resections and support brain-function research.

Aim Mapped the topography of basal white-matter tracts and subcortical gray matter (including hippocampus, amygdala, and nucleus accumbens) and their relationships to cortex, ventricles, and nuclei.

Methods Performed Klingler-style layer-by-layer fiber dissection on 10 formalin-fixed human brains under ×6–×40 magnification, documenting each stage with stereoscopic 3D photography.

Key anatomy (basal tracts) Sequential basal dissection exposed U fibers, inferior cingulum (lower part), Li-Am fasciculus, SRF, and ILF; removing Li-Am/ILF revealed the temporal horn with the hippocampus medially.

Sagittal stratum layering The lateral wall of the atrium is layered (medial→lateral): ependyma, tapetum, IC-SL, optic radiations, posterior AC extension, IFOF, MdLF, posterior SLF/AF, U fibers, cortex—together forming the sagittal stratum.

ILF clarification The ILF was identified as a long association tract connecting the base of the temporal pole to the occipital base, located above the fusiform gyrus and beneath the sagittal stratum; “merging fibers” in lateral occipital base were distinguished from the temporal portion of the AF.

Amygdala connectivity The amygdala links to septal nuclei/hypothalamus/thalamus via the stria terminalis, projects to cortical regions via the uncinate fasciculus, and connects via additional pathways including amygdalofugal routes and the anterior commissure.

Surgical application (STIO case) A right hippocampal WHO grade 2 glioma was resected via a supratentorial-infraoccipital (STIO) approach; the fusiform gyrus was incised anterior to the basal turning point of the optic radiation to reach the lateral ventricle, and postoperative DTI confirmed optic-radiation preservation.

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A Validation of the Tarlov Cyst Quality-of-Life Survey in Men Surgically Treated for Symptomatic Spinal Tarlov Cysts

Operative Neurosurgery 30:379–384, 2026

This article validates the 11-item Tarlov Cyst Quality-of-Life (TCQoL) scale for male patients undergoing surgical treatment of sacral Tarlov cysts, demonstrating good internal consistency (Cronbach α = 0.85), significant postoperative improvement on nine items, and strong concurrent validity with ODI and SF-36 physical function and pain subscales. The TCQoL showed large responsiveness (SRM = 0.81) and correlated with VAS pain measures.

Methods include prospective preoperative and 3-month postoperative administration of TCQoL, ODI, SF-36, and VAS in 46 male patients treated surgically between 2016–2023, with detailed psychometric analyses assessing discriminative validity, construct validity, and responsiveness; limitations noted include small sample size, single-surgeon single-center design, and 20% attrition.

TCQoL Validation in Men: The Tarlov Cyst Quality-of-Life (TCQoL) scale, previously validated in women, was successfully validated for male patients undergoing surgical treatment for symptomatic sacral Tarlov cysts, demonstrating good internal consistency (Cronbach α = 0.85) and discriminative validity.

Study Population: The study included 46 male patients (final sample) with an average age of 48.4 years, mostly presenting with multiple sacral cysts and a median symptom duration of nearly 35 months.

Surgical Technique: Surgery involved a posterior approach with laminectomy, cyst drainage, and wrapping of the nerve root with a bovine pericardium sleeve to prevent refilling, followed by closure with a resorbable plate.

Symptom Improvement: Significant improvement was observed in 9 of 11 TCQoL items postoperatively, especially for discomfort while sitting, sacral pain, lower extremity pain, and weakness; sexual function items showed no significant change.

Correlation with Established Measures: The TCQoL showed strong positive correlation with the Oswestry Disability Index (ODI) (r = 0.63, P < .001) and moderate to strong negative correlations with key SF-36 subscales (physical function, bodily pain, vitality, and social functioning), indicating good concurrent validity.

Scale Responsiveness: The standardized response mean (SRM) for TCQoL was 0.81, indicating a large effect size and sensitivity to clinical change after surgery.

Limitations: The study is limited by a small sample size (reflecting the rarity of Tarlov cysts in men), single-center and single-surgeon design, and a 20% attrition rate; findings may not generalize to non-sacral or non-Tarlov cysts.

Clinical Utility: The TCQoL can now be used as a disease-specific HRQoL tool for both male and female patients with symptomatic sacral Tarlov cysts, supporting standardized outcome measurement in future research and clinical practice.

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Partial sensory rhizotomy in therapy‑refractory and recurrent trigeminal neuralgia

Acta Neurochirurgica (2026) 168:42

This single-center retrospective analysis reports outcomes of partial sensory rhizotomy (PSR) for therapy-refractory or recurrent trigeminal neuralgia (TN) in 48 patients treated between 2004 and 2023. The study details patient selection, surgical technique, and perioperative findings, noting immediate pain relief in most patients, variable hypesthesia, and acceptable complication rates without permanent deficits.

Long-term follow-up (mean 38 months) found 65% pain-free without medication and 95% overall satisfaction (BNI 1–3), including a substantive subset with multiple sclerosis; recurrence occurred in 27% with some successfully re-operated. The authors conclude PSR is a viable option for selected refractory or recurrent TN patients, emphasizing informed consent about unpredictable sensory deficits

Partial Sensory Rhizotomy (PSR) Role: PSR is a surgical option for therapy-refractory or recurrent trigeminal neuralgia (TN), especially in patients without neurovascular conflict or those who failed previous microvascular decompression (MVD) or other interventions.

Efficacy: PSR provided immediate total pain relief in 87.5% (42/48) of patients; long-term, 72.1% (31/43) had complete or partial pain relief without medication, and 23.3% were satisfied with ongoing medication.

Indications: PSR is particularly relevant for patients with multiple sclerosis (MS)-related TN and those without a clear neurovascular conflict, as well as for those not responding to or preferring to avoid repeated percutaneous or radiosurgical procedures.

Complications: Postoperative hypesthesia is expected and occurred in 77.1% of patients, but was generally well tolerated; no cases of anesthesia dolorosa or corneal anesthesia were observed. Other complications (e.g., CSF fistula, transient hearing impairment) were rare and resolved with treatment.

Recurrence: The observed recurrence rate after PSR was 27.1%, consistent with previously reported rates (10–49% over five years), and repeat PSR was effective in patients with recurrent pain.

Comparison with Other Treatments: While MVD is preferred when neurovascular conflict is present, PSR offers comparable long-term pain relief in selected patients, but with a higher risk of sensory deficits. Combined MVD+PSR does not improve long-term outcomes if no vascular conflict exists.

Patient Satisfaction: Overall, 95% of patients reported meaningful improvement and satisfaction with PSR, despite sensory deficits, when adequately counseled preoperatively.

Recommendation: PSR should be considered and discussed as a viable surgical alternative for therapy-refractory or recurrent TN, particularly in MS patients and those not suitable for or preferring to avoid other invasive procedures.

 

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Postoperative loss in segmental lumbar lordosis following L5–S1 anterior lumbar interbody fusion

J Neurosurg Spine 44:420–425, 2026

This clinical study evaluates predictors and thresholds for postoperative loss of L5–S1 segmental lordosis following anterior lumbar interbody fusion (ALIF) in 94 adults treated for degenerative disc disease. Multivariate analyses identified baseline obesity, absence of posterior fixation, and larger immediate lordotic correction as independent predictors of 6-week to 1-year segmental lordosis loss, which related to higher rates of cage subsidence and revision.

The authors derived 6-week postoperative L5–S1 lordosis thresholds (overall range 21.6°–26.8°, PI-specific: low 19.0°–24.8°, average 21.0°–26.4°, high 24.1°–28.7°) that minimized subsequent loss and need for revision. Findings support targeted preoperative planning to achieve sustainable correction while balancing risks of overcorrection and subsidence.

Segmental Lordosis Restoration: L5–S1 anterior lumbar interbody fusion (ALIF) provides strong and durable correction of segmental lumbar lordosis and disc height, with most correction maintained at 1 year postoperatively.

Predictors of Lordosis Loss: Baseline obesity, lack of posterior fixation, and larger initial correction in L5–S1 lordosis are independent predictors of postoperative segmental lordosis loss within 1 year.

Complications: Loss of segmental lordosis increases the risk of cage subsidence and revision surgery, particularly due to pseudarthrosis.

Optimal Correction Thresholds: Achieving 6-week postoperative L5–S1 segmental lordosis between 21.6° and 26.8° minimizes the risk of lordotic loss and need for revision; PI-specific thresholds are 19.0°–24.8° (low PI), 21.0°–26.4° (average PI), and 24.1°–28.7° (high PI).

Risks of Overcorrection/Undercorrection: Overcorrection (>26.8°) increases risk of cage subsidence and mechanical complications, while undercorrection (<21.6°) may predispose to implant failure and adjacent segment disease.

Surgical Planning Importance: Preoperative planning should target lordosis correction within these thresholds and consider modifiable risk factors to optimize outcomes and reduce complications.

Comparison to Other Techniques: ALIF offers greater segmental correction than other lumbar interbody fusion techniques such as TLIF or XLIF.

Clinical Implications: Nearly half of patients experience some degree of lordosis loss post-ALIF, highlighting the need for careful patient selection, surgical technique, and postoperative monitoring.

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