Freehand stereotactic ventricular catheter insertion for ventriculoperitoneal shunts based on individualized radio-anatomical landmarks

Acta Neurochirurgica (2021) 163:1103–1112

The accurate placement of the ventricular catheter (VC) is critical in reducing the incidence of proximal failure of ventriculoperitoneal shunts (VPSs). The standard freehand technique is based on validated external anatomical landmarks but remains associated with a relatively high rate of VC malposition. Already proposed alternative methods have all their specific limitations. Herein, we evaluate the accuracy of our adapted freehand technique based on an individualized radio-anatomical approach. Reproducing the preoperative imaging on the patient’s head using common anatomical landmarks allows to define stereotactic VC coordinates to be followed at surgery.

Material and methods Fifty-five consecutive patients treated with 56 VPS between 11/2005 and 02/2020 fulfilled the inclusion criteria of this retrospective study. Burr hole coordinates, VC trajectory, and length were determined in all cases on preoperative computed tomography (CT) scan and were accurately reported on patients’ head. The primary endpoint was to evaluate VC placement accuracy. The secondary endpoint was to evaluate the rate and nature of postoperative VC-related complications.

Results Our new technique was applicable in all patients and no VC-related complications were observed. Postoperative imaging showed VC optimally placed in 85.7% and sub-optimally placed in 14.3% of cases. In all procedures, all the holes on the VC tip were found in the ventricular system.

Conclusions This simple individualized technique improves the freehand VC placement in VPS surgery, making its accuracy comparable to that of more sophisticated and expensive techniques. Further randomized controlled studies are required to compare our results with those of the other available techniques.

Telemedicine in the Evaluation and Management of Neurosurgical Spine Patients

Spine 2021;46:472–477

Study Design. Retrospective questionnaire study of all patients seen via telemedicine during the COVID-19 pandemic at a large academic institution.

Objective. This aim of this study was to compare patient satisfaction of telemedicine clinic to in-person visits; to evaluate the preference for telemedicine to in-person visits; to assess patients’ willingness to proceed with major surgery and/or a minor procedure based on a telemedicine visit alone.

Summary of Background Data. One study showed promising utility of mobile health applications for spine patients. No studies have investigated telemedicine in the evaluation and management of spine patients.

Methods. An 11-part questionnaire was developed to assess the attitudes toward telemedicine for all patients seen within a 7- week period during the COVID-19 crisis. Patients were called by phone to participate in the survey. x2 and the Wilcoxon Rank-Sum Test were performed to determine significance.

Results. Ninety-five percent were ‘‘satisfied’’ or ‘‘very satisfied’’ with their telemedicine visit, with 62% stating it was ‘‘the same’’ or ‘‘better’’ than previous in-person appointments. Patients saved a median of 105 minutes by using telemedicine compared to inperson visits. Fifty-two percent of patients have to take off work for in-person visits, compared to 7% for telemedicine. Thirtyseven percent preferred telemedicine to in-person visits. Patients who preferred telemedicine had significantly longer patient reported in-person visit times (score mean of 171) compared to patients who preferred in-person visits (score mean of 137, P=0.0007). Thirty-seven percent of patients would proceed with surgery and 73% would proceed with a minor procedure based on a telemedicine visit alone.

Conclusion. Telemedicine can increase access to specialty care for patients with prolonged travel time to in-person visits and decrease the socioeconomic burden for both patients and hospital systems. The high satisfaction with telemedicine and willingness to proceed with surgery suggest that remote visits may be useful for both routine management and initial surgical evaluation for spine surgery candidates.

Level of Evidence: 3

Woven Endobridge Embolization Versus Microsurgical Clipping for Unruptured Anterior Circulation Aneurysms

Neurosurgery 88:779–784, 2021

Intrasaccular flow-disruption represents a new paradigmin endovascular treatment of wide-necked bifurcation aneurysms.

OBJECTIVE: To retrospectively compare Woven Endobridge (WEB) embolization with microsurgical clipping for unruptured anterior circulation aneurysms using propensity score adjustment.

METHODS: A total of 63 patients treated with WEB and 103 patients treated with clipping were compared based on the intention-to-treat principle. The primary outcome measures were immediate technical treatment success, major adverse events, and 6-mo complete aneurysm occlusion.

RESULTS: The technical success rates were 83% forWEB and 100% for clipping. Procedure related complications occurred more often in the clipping group (13%) than the WEB group (6%, adjusted P<.01). However, the rates of major adverse events were comparable in both groups (WEB: 3%, clip: 4%, adjusted P = .53). At the 6-mo follow-up, favorable functional outcomes were achieved in 98% of the WEB embolization group and 99% of the clipping group (adjusted P = .19). Six-month complete aneurysm occlusion was obtained in 75% of the WEB group and 94% of the clipping group (adjusted P < .01).

CONCLUSION: Microsurgical clipping was associated with higher technical success and complete occlusion rates, whereas WEB had a lower complication rate. Favorable functional outcomes were achieved in≥98% of both groups. The decision to use a specific treatment modality should be made on an individual basis and in accordance with the patient’s preferences.

Subclinical imaging changes in cerebral cavernous angiomas during prospective surveillance

J Neurosurg 134:1147–1154, 2021

The purpose of this study was to systematically assess asymptomatic changes (ACs), including subclinical hemorrhage, growth, or new lesion formation (NLF) during longitudinal follow-up of cerebral cavernous angiomas (CAs), and to correlate these with symptomatic hemorrhage (SH) during the same period and with clinical features of the disease.

METHODS One hundred ninety-two patients were included in this study, among 327 consecutive patients with CA, prospectively identified between September 2009 and February 2019. Included patients had undergone clinical and MRI follow-up, in conjunction with institutional review board–approved biomarker studies, and harbored ≥ 1 CA with a maximum diameter of ≥ 5 mm on T2-weighted MRI. Rates of AC and SH per lesion-year and patient-year were assessed using prospectively articulated criteria. In multifocal/familial cases, rates of NLF were also assessed.

RESULTS There were no differences in demographic or disease features among cases included or excluded in the study cohort, except for a higher proportion of included patients with CCM3 mutation. Follow-up was 411 patient-years (2503 lesion-years). The rate of AC was higher than the rate of SH (12.9% vs 7.5% per patient-year, and 2.1% vs 1.2% per lesion-year, both p = 0.02). Patients presenting with a prior history of SH had a higher rate of AC than those with other forms of presentation (19.7% and 8.2% per patient-year, respectively; p = 0.003). A higher rate of NLF on T2-weighted MRI (p = 0.03) was observed in patients with prior SH. Three of 6 solitary/sporadic and 2 of 28 multifocal/familial patients underwent resection of the lesion after AC.

CONCLUSIONS Rates of AC are greater than SH during prospective follow-up of CAs, and greater in cases with prior SH. AC may be a more sensitive biomarker of lesional activity, and a more efficient surrogate outcome in clinical trials than SH. Patients experiencing an AC are more likely to undergo a surgical intervention when CAs are solitary/sporadic than when they are multifocal/familial.

 

Anatomical multifocal high-grade glioma resection

Acta Neurochirurgica (2021) 163:953–957

If an awake surgery is somehow not available for gliomas at the language area, understanding the anatomy and well designed surgical strategy are important.

Method We present a case with left hemispheric multifocal high-grade gliomas located deeply at the left temporal pole, the Wernicke’s area, and mesial temporal region. Because the patient could not endure the awake surgery and obtain practicable functional magnetic resonance imaging (MRI) for eloquent cortex evaluation, we removed the lesions following the anatomical resection strategy guided by diffusion tensor imaging (DTI).

Conclusion This case demonstrates the value of DTI and the importance of anatomical resection strategies in glioma surgeries.

Results of a third Gamma Knife radiosurgery for trigeminal neuralgia

J Neurosurg 134:1237–1243, 2021

Gamma Knife radiosurgery (GKRS) is a commonly used procedure for medically refractory trigeminal neuralgia (TN), with repeat GKRS routinely done in cases of pain relapse. The results of a third GKRS in cases of further pain relapse have not been well described. In this study, the authors report the largest series of patients treated with a third GKRS for TN to date.

METHODS Retrospective review of institutional electronic medical records and a GKRS database was performed to identify patients who had been treated with a third GKRS at the authors’ institution in the period from 2010 to 2018. Telephone interviews were used to collect long-term follow-up data. Pain outcomes were measured using the Barrow Neurological Institute (BNI) pain intensity scale, with a score ≤ IIIb indicating successful treatment.

RESULTS Twenty-two nerves in 21 patients had sufficient follow-up to determine BNI pain score outcomes. Eighteen of 22 cases had a successful third GKRS, with a median durability of pain relief of 3.88 years. There was no significant difference in the durability of pain relief after a third GKRS compared with those of institutional historical controls of prior series of first and second GKRS procedures. Ten cases had new or worsening facial numbness, with 1 case being bothersome. Four cases of toxicity other than facial numbness were reported, including 1 case of corneal abrasions and possible neurotrophic keratopathy. No cases of anesthesia dolorosa were reported. No factors predicting treatment success or the durability of pain relief were identified. Nonnumbness toxicity was more common in those with a proximally placed shot at the third GKRS.

CONCLUSIONS A third GKRS is an effective treatment option for TN patients who have pain relapse after repeat GKRS. Pain outcomes of a third GKRS are similar to those following a first or second GKRS. Toxicity is tolerable in patients with a distally placed shot at the third GKRS.

 

Using Smartphone-Based Accelerometer Data to Objectively Assess Outcomes in Spine Surgery

Neurosurgery 88:763–772, 2021

In order to deliver optimal patient care, spine surgeons must integrate technological changes to arrive at novel measures of functional outcomes. Historically, subjective patient-reported outcome (PRO) surveys have been used to determine the relative benefit of surgical treatments. Using smartphone-based accelerometers, surgeons now have the ability to arrive at objective outcome metrics.

OBJECTIVE: To use Apple Health (Apple Inc, Cupertino, California) data to approximate physical activity levels before and after spinal fusion as an objective outcome measurement.

METHODS: Personal activity data were acquired retrospectively from the cellphones of consenting patients. These data were used to measure changes in activity level (daily steps, flights climbed, and distance traveled) before and after patients underwent spine surgery at a single institution by a single surgeon. After data collection, we investigated the demographic information and daily physical activity pre- and postoperatively of participating patients.

RESULTS: Twenty-three patients were included in the study. On average, patients first exceeded their daily 1-yr average distancewalked, flights climbed, and steps taken at 10.3± 14, 7.6±21.1, and 8±9.9wk, respectively. Mean flights climbed, distance traveled, and steps taken decreased significantly from 6mo prior to surgery to 2 wk postoperatively. Distance traveled and steps taken significantly increased from 6 mo prior to surgery to 7 to 12 mo postoperatively.

CONCLUSION: We demonstrated a valuable supplement to traditional PROs by using smartphone-based activity data. This methodology yields a rich data set that has the potential to augment our understanding of patient recovery.

Readmission and reoperation for hydrocephalus: a population-based analysis across the spectrum of age

J Neurosurg 134:1210–1217, 2021

Hydrocephalus is a common, chronic illness that generally requires lifelong, longitudinal, neurosurgical care. Except at select research centers, surgical outcomes in the United States have not been well documented. Comparative outcomes across the spectrum of age have not been studied.

METHODS Data were derived for the year 2015 from the Nationwide Readmissions Database, a product of the Healthcare Cost and Utilization Project of the Agency for Healthcare Research and Quality. In this data set patients are assigned state-specific codes that link repeated discharges through the calendar year. Discharges with diagnostic codes for hydrocephalus were extracted, and for each patient the first discharge defined the index admission. The study event was readmission. Observations were censored at the end of the year. In a similar fashion the first definitive surgical procedure for hydrocephalus was defined as the index operation, and the study event was reoperation for hydrocephalus or complications. Survival without readmission and survival without reoperation were analyzed using life tables and Kaplan- Meier plots.

RESULTS Readmission rates at 30 days ranged between 15.6% and 16.8% by age group without significant differences. After the index admission the first readmission alone generated estimated hospital charges of $2.25 billion nationwide. Reoperation rates at 30 days were 34.9% for infants, 39.2% for children, 47.4% for adults, and 32.4% for elders. These differences were highly significant. More than 3 times as many index operations were captured for adults and elders as for infants and children. Estimated 1-year reoperation rates were 74.2% for shunt insertion, 63.9% for shunt revision, but only 34.5% for endoscopic third ventriculostomy. Univariate associations with survival without readmission and survival without reoperation are presented.

CONCLUSIONS In the United States hydrocephalus is predominantly a disease of adults. Surgical outcomes in this population-based study were substantially worse than outcomes reported from research centers. High reoperation rates after CSF shunt surgery accounted for this discrepancy.

Modified far lateral endoscopic transforaminal lumbar interbody fusion using a biportal endoscopic approach

Acta Neurochirurgica (2021) 163:1205–1209

Endoscopic transforaminal lumbar interbody fusion (TLIF) has the disadvantage of the small cage size and by consequence risk for cage subsidence. We succeeded to insert a large oblique lumbar interbody fusion (OLIF) cage during biportal endoscopic TLIF.

Methods Unilateral total facetectomy was performed to expose the exiting and traversing nerve roots. The distance between the exiting and traversing nerve roots was measured before OLIF cage insertion. We inserted an OLIF cage instead of a TLIF cage.

Conclusion We successfully performed modified far lateral biportal endoscopic TLIF using large OLIF cages. Modified far lateral biportal endoscopic TLIF is usually suitable for the L4-5 and L5-S1 levels.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Deep Brain Stimulations for Obsessive-Compulsive Disorder: Update of the 2014 Guidelines

 Neurosurgery 88:710–712, 2021

In 2020, the Guidelines Task Force conducted another systematic review of the relevant literature on deep brain stimulation (DBS) for obsessive-compulsive disorder (OCD) to update the original 2014 guidelines to ensure timeliness and accuracy for clinical practice.

OBJECTIVE: To conduct a systematic review of the literature and update the evidencebased guidelines on DBS for OCD.

METHODS: The Guidelines Task Force conducted another systematic review of the relevant literature, using the same search terms and strategies as used to search PubMed and Embase for relevant literature. The updated search included studies published between 1966 and December 2019. The same inclusion/exclusion criteria as the original guideline were also applied. Abstracts were reviewed and relevant full-text articles were retrieved and graded. Of 864 articles, 10 were retrieved for full-text review and analysis. Recommendations were updated according to new evidence yielded by this update.

RESULTS: Seven studies were included in the original guideline, reporting the use of bilateral DBS as more effective in improving OCD symptoms than sham treatment. An additional 10 studies were included in this update: 1 class II and 9 class III.

CONCLUSION: Based on the data published in the literature, the following recommendations can be made: (1) It is recommended that clinicians utilize bilateral subthalamic nucleus DBS over best medical management for the treatment of patients with medically refractory OCD (level I). (2) Cliniciansmay use bilateral nucleus accumbens or bed nucleus of stria terminalis DBS for the treatment of patientswithmedically refractory OCD (level II). There is insufficient evidence to make a recommendation for the identification of themost effective target. The full guidelines can be accessed at https://www.cns.org/guidelines/browse-guidelinesdetail/ deep-brain-stimulation-obsessive-compulsive-disord.

How I do it: minimizing muscle damage in microvascular decompression for hemifacial spasm

Acta Neurochirurgica (2021) 163:1045–1048

Key hole surgery was recruited for MVD surgery since the maneuver is through the small space between the cerebellum and temporal/occipital bone. However, even small wounds can cause severe postoperative pain if there is significant tissue damage. Attention has been given to the size of the craniotomy rather than to the skin incision or soft tissues such as muscles.

Method Suboccipital muscle dissection focusing on splitting the splenius capitis muscle was presented. The dura was reapproximated without additional dissection to harvest a fascia graft.

Conclusion Muscle injury should be minimized to alleviate postoperative pain.

Effect of Topical Steroid on Swallowing Following ACDF

Spine 2021;46:413–420

Study Design. Randomized, double-blinded, controlled trial.

Objective. To investigate the effectiveness of local intraoperative corticosteroids at decreasing the severity of swallowing difficulty following multilevel anterior cervical discectomy and fusion (ACDF).

Summary of Background Data. Dysphagia is a common complication after ACDF, and while for most patients the symptoms are mild and transient, some patients can suffer from severe dysphagia resulting in significant postoperative morbidity. Previous studies investigating the local application of corticosteroids are limited.

Methods. This was a prospective, randomized, double-blinded, controlled trial of patients undergoing 2, 3, or 4 level ACDF for radiculopathy and/or myelopathy. Patients undergoing multilevel ACDF were randomized to receive local corticosteroid in the retropharyngeal space or placebo (no steroid). Dysphagia was assessed using validated outcomes including the Eating Assessment Tool-10 (Eat-10) and Swallowing Quality of Life (SWALQOL) Questionnaire both preoperatively and at 1 day (POD1), 2 days (POD2), and 1-month postoperatively.

Results. One-hundred nine patients had a complete dataset available for analysis. Eat-10 scores were significantly lower in the Steroid group on POD2 (8 vs. 16, P¼0.03) and 1-month postoperatively (2 vs. 5, P¼0.03). A comparison of the individual SWAL-QOL subscale scores demonstrated that patients in the Steroid group had better scores than the Control group in various subscales at all postoperative time points. Significant differences were noted (always in favor of the Steroid group) in 40% of subscales on POD1, 60% of subscales on POD2, and 50% of subscales at 1-month postoperatively. The Control group never had a better SWAL-QOL subscale score at any time point postoperatively.

Conclusion. Local administration of corticosteroid after multilevel ACDF can decrease postoperative severity and symptomatology of dysphagia during the immediate postoperative period to 1-month postoperatively. The long-term effects of local steroid administration on fusion and other complications will need to be established in future studies.

Level of Evidence: 1

Surgical clipping of ophthalmic artery aneurysms

British Journal of Neurosurgery, 35:2, 157-160

The purpose of this study was to summary the characteristics of ophthalmic artery (OphA) aneurysms and to obtain the independent risk factors for poor prognosis of microsurgical clipping treatment for OphA aneurysms.

Methods: The clinical and microsurgical clipping results of all 63 patients with ophthalmic aneurysm were investigated and reviewed. The OphA aneurysm patient’s case records were reviewed including clinical characteristics, image findings, and clinical outcomes. Then, the risk factors of poor prognosis were analyzed retrospectively.

Results: Monocular blindness persisted in 4 patients (6.35%), 1 patient developed persistent vegetate state (PVS) (1.59%), while 4 patients (6.35%) died. The matching process constructed a cohort consisting of 9 poor outcome (Glasgow Outcome Scale, GOS 1–3) patients (14.3%), and 54 good outcome (GOS 4–5) patients (85.7%). Univariate analysis between the good outcome and poor outcome revealed statistical significance in age > 60 (p¼0.045), size (p¼0.016), and rupture before operation (p¼0.049). Further, multivariate logistic regression analysis identified age > 60 (odds ratio [OR], 5.877; 95% confidence interval [CI], 1.039–33.254; p¼0.045) and aneurysm size > 10mm (OR, 9.417; 95% CI, 1.476–60.072; p¼0.018) as the independent risk factors for poor outcome in microsurgical clipping treatment for OphA aneurysms.

Conclusion: The significant independent risk factors associated with clipping OphA aneurysms are age (>60) and size (>10mm).

 

How safe are elective craniotomies in elderly patients in neurosurgery today?

J Neurosurg 134:1113–1121, 2021

With global aging, elective craniotomies are increasingly being performed in elderly patients. There is a paucity of prospective studies evaluating the impact of these procedures on the geriatric population. The goal of this study was to assess the safety of elective craniotomies for elderly patients in modern neurosurgery.

METHODS For this cohort study, adult patients, who underwent elective craniotomies between November 1, 2011, and October 31, 2018, were allocated to 3 age groups (group 1, < 65 years [n = 1008], group 2, ≥ 65 to < 75 [n = 315], and group 3, ≥ 75 [n = 129]). Primary outcome was the 30-day mortality after craniotomy. Secondary outcomes included rate of delayed extubation (> 1 hour), need for emergency head CT scan and reoperation within 48 hours after surgery, length of postoperative intensive or intermediate care unit stay, hospital length of stay (LOS), and rate of discharge to home. Adjustment for American Society of Anesthesiologists Physical Status (ASA PS) class, estimated blood loss, and duration of surgery were analyzed as a comparison using multiple logistic regression. For significant differences a post hoc analysis was performed.

RESULTS In total, 1452 patients (mean age 55.4 ± 14.7 years) were included. The overall mortality rate was 0.55% (n = 8), with no significant differences between groups (group 1: 0.5% [95% binominal CI 0.2%, 1.2%]; group 2: 0.3% [95% binominal CI 0.0%, 1.7%]; group 3: 1.6% [95% binominal CI 0.2%, 5.5%]). Deceased patients had a significantly higher ASA PS class (2.88 ± 0.35 vs 2.42 ± 0.62; difference 0.46 [95% CI 0.03, 0.89]; p = 0.036) and increased estimated blood loss (1444 ± 1973 ml vs 436 ± 545 ml [95% CI 618, 1398]; p <0.001). Significant differences were found in the rate of postoperative head CT scans (group 1: 6.65% [n = 67], group 2: 7.30% [n = 23], group 3: 15.50% [n = 20]; p = 0.006), LOS (group 1: median 5 days [IQR 4; 7 days], group 2: 5 days [IQR 4; 7 days], and group 3: 7 days [5; 9 days]; p = 0.001), and rate of discharge to home (group 1: 79.0% [n = 796], group 2: 72.0% [n = 227], and group 3: 44.2% [n = 57]; p < 0.001).

CONCLUSIONS Mortality following elective craniotomy was low in all age groups. Today, elective craniotomy for well selected patients is safe, and for elderly patients, too. Elderly patients are more dependent on discharge to other hospitals and postacute care facilities after elective craniotomy. Clinical trial registration no.: NCT01987648 (clinicaltrials.gov).

MGMT-Positive vs MGMT-Negative PatientsWith Glioblastoma: Identification of Prognostic Factors and Resection Threshold

Neurosurgery 88:E323–E329, 2021

The importance of the O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status as a predictive factor for the response to chemotherapy with temozolomide is well established. Its significance though at stratifying glioblastoma (GBM) patients in regard to their prognostic factors and the impact of surgical approach on them has not been identified.

OBJECTIVE: To reveal possible differences in the prognostic factors and the impact of surgery between GBM patients stratified according to their MGMT status.

METHODS: The authors retrospectively analyzed 186 patients with a newly diagnosed primary supratentorial GBM treated with surgical resection followed by standard radiation and chemotherapy. A prospective quantitative volumetric analysis of tumor characteristics identified on magnetic resonance imaging was performed.

RESULTS: For the 109 patients with unmethylated MGMT promoter, extent of resection (EOR) represented independent predictor of survival, whereas residual tumor volume (RTV), Karnofsky Performance Score, and age were found to be independent prognostic factors of survival for the 77 patients with methylated MGMT promoter. For the group of patients with unmethylated and the group with methylated MGMT promoter, an EOR threshold of 70% and 98% and an RTV threshold of 1.5 and 1 cm3 were identified, respectively.

CONCLUSION: The selection of patients according to the MGMT promoter methylation status resulted in different prognostic factors and different resection thresholds for each patient population. A survival benefit seen from 70% EOR threshold in patients with MGMT unmethylated GBM supports the doctrine of maximum safe resection rather than the “all or- nothing” approach.

Comparative anatomical analysis between the minipterional and supraorbital approaches

J Neurosurg 134:1276–1284, 2021

Keyhole approaches, namely the minipterional approach (MPTa) and the supraorbital approach (SOa), are alternatives to the standard pterional approach to treat lesions located in the anterior and middle cranial fossae. Despite their increasing popularity and acceptance, the indications and limitations of these approaches require further assessment. The purpose of the present study was to determine the differences in the area of surgical exposure and surgical maneuverability provided by the MPTa and SOa.

METHODS The areas of surgical exposure afforded by the MPTa and SOa were analyzed in 12 sides of cadaver heads by using a microscope and a neuronavigation system. The area of exposure of the region of interest and surgical freedom (maneuverability) of each approach were calculated.

RESULTS The area of exposure was significantly larger in the MPTa than in the SOa (1250 ± 223 mm2 vs 939 ± 139 mm2, p = 0.002). The MPTa provided larger areas of exposure in the ipsilateral and midline compartments, whereas there was no significant difference in the area of exposure in the contralateral compartment. All targets in the anterior circulation had significantly larger areas of surgical freedom when treated via the MPTa versus the SOa.

CONCLUSIONS The MPTa provides greater surgical exposure and better maneuverability than that offered by the SOa. The SOa may be advantageous as a direct corridor for treating lesions located in the contralateral side or in the anterior cranial fossa, but the surgical exposure provided in the midline region is inferior to that exposed by the MPTa.

Free-hand stereotactic ventricular catheter insertion technique based on radio-anatomical landmarks

Acta Neurochirurgica (2021) 163:1097–1102

Accurate ventricular catheter (VC) placement plays an important role in reducing the risk of ventriculoperitoneal shunt failure. Free-hand VC insertion is associated with a significant misplacement rate. Consequently, several expensive alternative methods that are unfortunately not available worldwide have been used. To overcome these limitations, we developed a simple surgical technique based on radio-anatomical landmarks aimed at reducing VC’s misplacements.

Method We reproduce the preoperative imaging on the patient’s head using common anatomical landmarks. This allows defining stereotactic VC coordinates to be followed during the surgical procedure.

Conclusion This simple and cost-effective method improves VC insertion accuracy.

The Zap-X Radiosurgical System in the Treatment of Intracranial Tumors

Neurosurgery 88:E351–E355, 2021

The Zap-X system (Zap Surgical Systems Inc, San Carlos, California) is a radically new surgical robot designed for brain and head and neck radiosurgery. It represents the first new dedicated brain stereotactic radiosurgery platform in almost half a century optimizing the goals of safety, speed, and accuracy. The Zap-X system was used in a required Chinese National Medical Products Administration clinical study. In early January 2020, 2 patientswere treatedwith the Zap-X robot prior to a national COVID-19 lockdown. Both were closely followed via clinical exam andmagnetic resonance imaging (MRI) imaging. Prospectively collected data were used to generate this report.

CLINICAL PRESENTATION: Two female patients, each harboring either a trigeminal schwannoma or petroclival meningioma, were treated with the Zap-X robot. Respective tumor volumes were 2.60 and 4.02 cm3. A radiation dose of 13 Gy was prescribed to the 50% isodose line. At 8 mo of follow-up, preoperative symptoms were either resolved or stable and MRI imaging demonstrated a 31% and 56% reduction in lesion volume, respectively. In both patients, symptoms improved, and tumor volumes decreased, whereas no major complication was observed.

CONCLUSION: Given only 2 patients and short-term follow-up, any conclusions about the safety and efficacy of the Zap-X radiosurgery robot are preliminary. However, in the absence of any other published outcomes to date, this small case seriesmay be of interest to many radiosurgical specialists.

Microvascular decompression for trigeminal neuralgia attributable to the vertebrobasilar artery

Acta Neurochirurgica (2021) 163:1037–1043

Separation of the vertebrobasilar artery (VBA) from the trigeminal nerve root in microvascular decompression (MVD) is technically challenging. This study aimed to review the clinical features of VBA involvement in trigeminal neuralgia and evaluate surgical decompression techniques in the long term.

Methods We retrospectively reviewed the surgical outcomes of 26 patients (4.4%) with VBA involvement in 585 consecutive MVDs for TGN using a Teflon roll for repositioning the VBA. The final operative status of the nerve decompression was categorized into two groups: the separation group and the contact group. Separation of the VBA from the nerve root was completed in 13 patients in the separation group, and slight vascular contact remained in the remaining 13 patients of the contact group. The clinical features of VBA-related TGN were investigated and the operative results were analyzed.

Results Multiple arteries are involved in neurovascular compression (NVC) in most cases. The anterior inferior cerebellar artery was the most common concomitant artery (69%). The site of the NVC varies from the root entry zone to the distal portion of the root. All patients were pain-free immediately after surgery and maintained medication-free status during the follow-up period, except for one patient (3.8%) who had recurrent facial pain 8 years after surgery. Postoperative facial numbness was observed in six patients (23%). Of these, one patient showed improvement within 3 months and the other five patients had persistent facial numbness (19.2%). Other neurological deficits include one dry eye, one diplopia due to trochlear nerve palsy, two decreased hearing (< 50 db), two facial weaknesses, and two cerebellar ataxia. Although most of them were transient, one dry eye, two hearing impairments, and one cerebellar ataxia became persistent deficits. Statistical analyses revealed no difference in surgical efficacy or complications in the long term between the two groups.

Conclusions Slightly remaining vascular contact does not affect pain relief in the long term. Our study indicated that once the tense trigeminal nerve is loosened, further attempts to mobilize the VBA are not necessary.

Alignment, Classification, Clinical Evaluation, and Surgical Treatment for Adult Cervical Deformity

Neurosurgery 88:864–883, 2021

Adult cervical deformity management is complex and is a growing field with many recent advancements. The cervical spine functions to maintain the position of the head plays a pivotal role in influencing subjacent global spinal alignment and pelvic tilt as compensatory changes occur to maintain horizontal gaze.

There are various types of cervical deformity and a variety of surgical options available. The major advancements in the management of cervical deformity have only been around for a few years and continue to evolve. Therefore, the goal of this article is to provide a comprehensive review of cervical alignment parameters, deformity classification, clinical evaluation, and surgical treatment of adult cervical deformity.

The information presented here may be used as a guide for proper preoperative evaluation and surgical treatment in the adult cervical deformity patient.