Intraoperative facial motor evoked potential monitoring for pontine cavernous malformation resection

J Neurosurg 132:265–271, 2020

The aim of this study was to predict postoperative facial nerve function during pontine cavernous malformation surgery by monitoring facial motor evoked potentials (FMEPs).

METHODS From 2008 to 2017, 10 patients with pontine cavernous malformations underwent total resection via the trans–fourth ventricle floor approach with FMEP monitoring. House-Brackmann grades and Karnofsky Performance Scale (KPS) scores were obtained pre- and postoperatively. The surgeries were performed using one of 2 safe entry zones into the brainstem: the suprafacial triangle and infrafacial triangle approaches. Six patients underwent the suprafacial triangle approach, and 4 patients underwent the infrafacial triangle approach. A cranial peg screw electrode was used to deliver electrical stimulation for FMEP by a train of 4 or 5 pulse anodal constant current stimulation. FMEP was recorded from needle electrodes on the ipsilateral facial muscles and monitored throughout surgery by using a threshold- level stimulation method.

RESULTS FMEPs were recorded and analyzed in 8 patients; they were not recorded in 2 patients who had severe preoperative facial palsy and underwent an infrafacial triangle approach. Warning signs appeared in all patients who underwent the suprafacial triangle approach. However, after temporarily stopping the procedures, FMEP findings during surgery showed recovery of the thresholds. FMEPs in patients who underwent the infrafacial triangle approach were stable during the surgery. House-Brackmann grades were unchanged postoperatively in all patients. Postoperative KPS scores improved in 3 patients, decreased in 1, and remained the same in 6 patients.

CONCLUSIONS FMEPs can be used to monitor facial nerve function during surgery for pontine cavernous malformations, especially when the suprafacial triangle approach is performed.

Lumbar drain trial outcomes of normal pressure hydrocephalus: a single-center experience of 254 patients

J Neurosurg 132:306–312, 2020

A short-term lumbar drain (LD) trial is commonly used to assess the response of normal pressure hydrocephalus (NPH) patients to CSF diversion. However, it remains unknown whether the predictors of passing an LD trial match the predictors of improvement after ventriculoperitoneal shunting. The aim of this study was to examine outcomes, complication rates, and associations between predictors and outcomes after an LD trial in patients with NPH.

METHODS The authors retrospectively reviewed the records of 254 patients with probable NPH who underwent an LD trial between March 2008 and September 2017. Multivariate regression models were constructed to examine predictors of passing the LD trial. Complications associated with the LD trial procedure were recorded.

RESULTS The mean patient age was 77 years and 56.7% were male. The mean durations of gait disturbance, cognitive decline, and urinary incontinence were 29 months, 32 months, and 28 months, respectively. Of the 254 patients, 30% and 16% reported objective and subjective improvement after the LD trial, respectively. Complications included a sheared LD catheter, meningitis, lumbar epidural abscess, CSF leak at insertion site, transient lower extremity numbness, slurred speech, refractory headaches, and hyponatremia. Multivariate analyses using MAX-R revealed that a prior history of stroke predicted worse outcomes, while disproportionate subarachnoid spaces (uneven enlargement of supratentorial spaces) predicted better outcomes after the LD trial (r2 = 0.12, p < 0.05).

CONCLUSIONS The LD trial is generally safe and well tolerated. The best predictors of passing the LD trial include a negative history of stroke and having disproportionate subarachnoid spaces.

 

Overview of Different Flow Diverters and Flow Dynamics

Neurosurgery 86:S21–S34, 2020

Over the past decade, flow diverter technology for endocranial aneurysms has seen rapid evolution, with the development of new devices quickly outpacing the clinical evidence base. However, flow diversion has not yet been directly compared to surgical aneurysm clipping or other endovascular procedures. The oldest and most well-studied device is the Pipeline Embolization Device (PED; Medtronic), recently transitioned to the Pipeline Flex (Medtronic), which still has sparse data regarding outcomes.

To date, other flow diverting devices have not been shown to outperform the PED, although information comes primarily from retrospective studies with short follow-up, which are not always comparable.

Because of this lack of high-quality outcome data, no reliable recommendations can be made for choosing among flow diversion devices yet. Moreover, the decision to proceed with flow diversion should be individualized to each patient.

In this work, we wish to provide a comprehensive overview of the technical specifications of all flow diverter devices currently available, accompanied by a succinct description of the evidence base surrounding each device.

Interlaminar contralateral endoscopic lumbar foraminotomy assisted with the O-arm navigation

Acta Neurochirurgica (2020) 162:121–125

The interlaminar contralateral endoscopic lumbar foraminotomy (ICELF) provides access to the foraminal pathology with less violation to facet than the ipsilateral approach. However, it is technically challenging even for an experienced surgeon.

Methods We introduce the step-by-step workflow of the interlaminar contralateral endoscopic lumbar foraminotomy assisted with O-arm navigation system.

Conclusion The ICELF assisted with O-arm navigation is safe, accurate, and efficient for the treatment of lumbar foraminal stenosis. The CT-based navigation reshapes the learning curve of the advanced endoscopic technique, reducing the risk of facet joint violation, and minimizes radiation exposure to surgeons.

Individual variations of the superior petrosal vein complex and their microsurgical relevance in 50 cases of trigeminal microvascular decompression

Acta Neurochirurgica (2020) 162:197–209

We investigated the understudied anatomical variations of the superior petrosal vein (SPV) complex (SPVC), which may play some role in dictating the individual complication risk following SPVC injury.

Methods Microvascular decompressions of the trigeminal nerve between September 2012 and July 2016. All operations utilized an SPVC preserving technique. Preoperative balanced fast field echo (bFFE) magnetic resonance imaging, or equivalent sequences, and operative videos were studied for individual SPVC anatomical features.

Results Applied imaging and operative SPVC anatomy were described for fifty patients (mean age, 67.18 years; female sex and right-sided operations, 58% each). An SPVC component was sacrificed intentionally in 6 and unintentionally in only 7 cases. Twenty-nine different individual variations were observed; 80% of SPVCs had either 2 SPVs with 3 or 1 SPV with 2, 3, or 4 direct tributaries. Most SPVCs had 1 SPV (64%) and 2 SPVs (32%). The SPV drainage point into the superior petrosal sinus was predominantly between the internal auditory meatus and Meckel cave (85.7% of cases). The vein of the cerebellopontine fissure was the most frequent direct tributary (86%), followed by the pontotrigeminal vein in 80% of SPVCs. Petrosal-galenic anastomosis was detected in at least 38%of cases. At least 1 SPVin 54%of the cases and at least 1 direct tributary in 90%disturbed the operative field. The tributaries were more commonly sacrificed.

Conclusions The extensive anatomical variation of SPVC is depicted. Most SPVCs fall into 4 common general configurations and can usually be preserved. BFFE or equivalent sequences remarkably facilitated the intraoperative understanding of the individual SPVC in most cases.

Long-term outcomes of high-dose single-fraction radiosurgery for chordomas of the spine and sacrum

J Neurosurg Spine 32:79–88, 2020

The current treatment of chordomas is associated with significant morbidity, high rates of local recurrence, and the potential for metastases. Stereotactic radiosurgery (SRS) as a primary treatment could reduce the need for en bloc resection to achieve wide or marginal margins. Spinal SRS outcomes support the exploration of SRS’s role in the durable control of these conventionally radioresistant tumors. The goal of the study was to evaluate outcomes of patients with primary chordomas treated with spinal SRS alone or in combination with surgery.

METHODS Clinical records were reviewed for outcomes of patients with primary chordomas of the mobile spine and sacrum who underwent single-fraction SRS between 2006 and 2017. Radiographic local recurrence-free survival (LRFS), overall survival (OS), symptom response, and toxicity were assessed in relation to the extent of surgery.

RESULTS In total, 35 patients with de novo chordomas of the mobile spine (n = 17) and sacrum (n = 18) received SRS and had a median post-SRS follow-up duration of 38.8 months (range 2.0–122.9 months). The median planning target volume dose was a 24-Gy single fraction (range 18–24 Gy). Overall, 12 patients (34%) underwent definitive SRS and 23 patients (66%) underwent surgery and either neoadjuvant or postoperative adjuvant SRS. Definitive SRS was selectively used to treat both sacral (n = 7) and mobile spine (n = 5) chordomas. Surgical strategies for the mobile spine were either intralesional, gross-total resection (n = 5) or separation surgery (n = 7) and for the sacrum en bloc sacrectomy (n = 11). The 3- and 5-year LRFS rates were 86.2% and 80.5%, respectively. Among 32 patients (91%) receiving 24-Gy radiation doses, the 3- and 5-year LRFS rates were 96.3% and 89.9%, respectively. The 3- and 5-year OS rates were 90.0% and 84.3%, respectively. The symptom response rate to treatment was 88% for pain and radiculopathy. The extent or type of surgery was not associated with LRFS, OS, or symptom response rates (p > 0.05), but en bloc resection was associated with higher surgical toxicity, as measured using the Common Terminology Criteria for Adverse Events (version 5.0) classification tool, than epidural decompression and curettage/intralesional resection (p = 0.03). The long-term rate of toxicity ≥ grade 2 was 31%, including 20% grade 3 tissue necrosis, recurrent laryngeal nerve palsy, myelopathy, fracture, and secondary malignancy.

CONCLUSIONS High-dose spinal SRS offers the chance for durable radiological control and effective symptom relief with acceptable toxicity in patients with primary chordomas as either a definitive or adjuvant therapy.

 

 

Endoscopic endonasal treatment of maxillary nerve (V2) painful neuropathy: cadaveric study with clinical correlation

Acta Neurochirurgica (2020) 162:223–229

Surgical access to the second (V2, maxillary) and third (V3, mandibular) branches of the trigeminal nerve (V) has been classically through a transoral approach. Increasing expertise with endoscopic anatomy has achieved less invasive, more efficient access to skull base structures. The authors present a surgical technique using an endoscopic endonasal approach for the treatment of painful V2 neuropathy.

Methods Endoscopic endonasal dissections using a transmaxillary approach were performed in four formalin-fixed cadaver heads to expose the V2 branch of the trigeminal nerve. Relevant surgical anatomy was evaluated and anatomic parameters for neurectomy were identified.

Results Endoscopic endonasal transmaxillary approaches completed bilaterally to the pterygopalatine and pterygomaxillary fossae exposed the V2 branch where it emerged from the foramen rotundum. The anatomy defined for the location of neurectomy was determined to be the point where V2 emerged from the foramen rotundum into the pterygopalatine fossa. The technique was then performed in 3 patients with intractable painful V2 neuropathy.

Conclusions In our cadaveric study and clinical cases, the endoscopic endonasal approach to the pterygopalatine fossa achieved effective exposure and treatment of isolated V2 painful neuropathy. Important surgical steps to visualize the maxillary nerve and its branches and key landmarks of the pterygopalatine fossa are discussed. This minimally invasive approach appears to be a valid alternative for select patients with painful V2 trigeminal neuropathy.

Eliciting Smiles and Laughter During Intraoperative Electric Stimulation of the Cingulum: Surgical Scenario

World Neurosurg. (2020) 133:55.

Laughter has a major role in daily social interactions; consequently, its biologic bases have been previously studied. Nevertheless, its cerebral representation remains unclear. The most accepted hypothesis has postulated that laughter has 2 components: mirth, related to the temporal and frontal neocortical areas, and motor aspect, related to the limbic system and brainstem. Furthermore, in prior studies, laughter has been elicited during electric stimulation with depth electrodes in the supplementary motor area and the cingulum.

This Video 1 reports resection of a right superior frontal gyrus diffuse astrocytoma (isocitrate dehydrogenase mutant, World Health Organization grade II) with awake intraoperative electric cortical and subcortical stimulation mapping. Diffusion tensor imaging (DTI) tractography, including all the tracts in relation to the tumor, was obtained preoperatively and postoperatively. Stimulation of the cingulum medially and inferiorly to the tumor elicited a patient’s smile and laugh without mirth or merriment. Also, this point correlated with the reconstructed cingulum in the intraoperatively navigated DTI tractography.

In conclusion, these findings support the anatomic subdivision of the laughter’s mechanism and the role of the cingulum in its motor component. Furthermore, smiles and laughter could be useful functional landmarks to identify the cingulum during subcortical mapping. Although it remains unclear whether pursuing resection beyond this point would have caused permanent postoperative deficits, considering laughter’s role in social interaction and other emotion-processing functions associated with the cingulum, in the future it could be potentially considered a functional limit of the resection of intrinsic tumors.

1-s2.0-S187887501932532X-mmc1.mp4

Face-to-face four hand technique in vestibular schwannoma surgery: results from 256 Danish patients with larger tumors

Acta Neurochirurgica (2020) 162:61–69

The objective of this study was to investigate the clinical outcome after microsurgical treatment of vestibular schwannomas using face-to-face four hand technique in 256 Danish patients treated in the Department of Neurosurgery at the Copenhagen University Hospital from 2009 to 2018.

Methods Data were retrospectively collected from patient records.

Results The mean tumor size was 30.6 mm and approximately 46% of the patients had tumors >30 mm. In around 1/3 of the patients a retrosigmoid approach was used and in 2/3 a translabyrinthine. In 50% of the patients, the tumor was completely removed, and in 38%, only smaller remnants were left to preserve facial function. The median operative time was approximately 2.5 h for retrosigmoid approach, and for translabyrinthine approach, it was around 3.5 h. One year after surgery, 84% of the patients had a good facial nerve function (House-Brackmann grade 1–2). In tumors ≤ 30 mm approximately 89%preserved good facial function, whereas this was only the case for around 78% of the patients with tumors > 30 mm. In 60% of the patients who had poor facial nerve function at hospital discharge, the function improved to good facial function within the 1 year follow-up period. Four patients died within 30 days after surgery, and 6% underwent reoperation for cerebrospinal fluid leakage.

Conclusion Surgery for vestibular schwannomas using face-to-face four hand technique may reduce operative time and can be performed with lower risk and excellent facial nerve outcome. The risk of surgery increases with increasing tumor size.

Stereotactic radiosurgery for arteriovenous malformations of the basal ganglia and thalamus: an international multicenter study

J Neurosurg 132:122–131, 2020

Arteriovenous malformations (AVMs) of the basal ganglia (BG) and thalamus are associated with elevated risks of both hemorrhage if left untreated and neurological morbidity after resection. Therefore, stereotactic radiosurgery (SRS) has become a mainstay in the management of these lesions, although its safety and efficacy remain incompletely understood. The aim of this retrospective multicenter cohort study was to evaluate the outcomes of SRS for BG and thalamic AVMs and determine predictors of successful endpoints and adverse radiation effects.

METHODS The authors retrospectively reviewed data on patients with BG or thalamic AVMs who had undergone SRS at eight institutions participating in the International Gamma Knife Research Foundation (IGKRF) from 1987 to 2014. Favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation- induced changes (RICs). Multivariable models were developed to identify independent predictors of outcome.

RESULTS The study cohort comprised 363 patients with BG or thalamic AVMs. The mean AVM volume and SRS margin dose were 3.8 cm3 and 20.7 Gy, respectively. The mean follow-up duration was 86.5 months. Favorable outcome was achieved in 58.5% of patients, including obliteration in 64.8%, with rates of post-SRS hemorrhage and permanent RIC in 11.3% and 5.6% of patients, respectively. Independent predictors of favorable outcome were no prior AVM embolization (p = 0.011), a higher margin dose (p = 0.008), and fewer isocenters (p = 0.044).

CONCLUSIONS SRS is the preferred intervention for the majority of BG and thalamic AVMs. Patients with morphologically compact AVMs that have not been previously embolized are more likely to have a favorable outcome, which may be related to the use of a higher margin dose.

 

A novel robot-guided minimally invasive technique for brain tumor biopsies

J Neurosurg 132:150–158, 2020

As decisions regarding tumor diagnosis and subsequent treatment are increasingly based on molecular pathology, the frequency of brain biopsies is increasing. Robotic devices overcome limitations of frame-based and frameless techniques in terms of accuracy and usability. The aim of the present study was to present a novel, minimally invasive, robot-guided biopsy technique and compare the results with those of standard burr hole biopsy.

METHODS A tubular minimally invasive instrument set was custom-designed for the iSYS-1 robot-guided biopsies. Feasibility, accuracy, duration, and outcome were compared in a consecutive series of 66 cases of robot-guided stereotactic biopsies between the minimally invasive (32 patients) and standard (34 patients) procedures.

RESULTS Application of the minimally invasive instrument set was feasible in all patients. Compared with the standard burr hole technique, accuracy was significantly higher both at entry (median 1.5 mm [range 0.2–3.2 mm] vs 1.7 mm [range 0.8–5.1 mm], p = 0.008) and at target (median 1.5 mm [range 0.4–3.4 mm] vs 2.0 mm [range 0.8–3.9 mm], p = 0.019). The incision-to-suture time was significantly shorter (median 30 minutes [range 15–50 minutes] vs 37.5 minutes [range 25–105 minutes], p < 0.001). The skin incision was significantly shorter (median 16.3 mm [range 12.7–23.4 mm] vs 28.4 mm [range 20–42.2 mm], p = 0.002). A diagnostic tissue sample was obtained in all cases.

CONCLUSIONS Application of the novel instrument set was feasible in all patients. According to the authors’ data, the minimally invasive robot-guidance procedure can significantly improve accuracy, reduce operating time, and improve the cosmetic result of stereotactic biopsies.

Incidence of Spontaneous Obliteration in Untreated Brain Arteriovenous Malformations

Neurosurgery 86:139–149, 2020

Spontaneous obliteration (SpO) of untreated arteriovenous malformations (AVMs) is rare with fewer than 100 cases reported. The incidence and predisposing factors of SpO remain unclear, impeding our understanding of lesion progression in untreated patients.

OBJECTIVE: To determine the incidence rate and predisposing factors of SpO in a North American cohort.

METHODS: AVMswere retrospectively evaluated at our institution for over 25 yr.Untreated AVMs were divided into 2 groups: SpO-AVMs and non-SpO-AVMs. All statistical results were based on univariate analyses. Incidence was generated from counts of SpO over the untreated interval in patient years frombirth until obliteration, treatment, or last follow-up.

RESULTS: One hundred fifty-four patients had untreated AVMs; SpO was observed in 4. Average ages were 49.0 ± 23.6 and 48.7 ± 20.4 yr in the SpO-AVM and non-SpO-AVM group, respectively (P=.98). Average AVMsizeswere 2.0±1.8 cm(SpO-AVMs) and 3.7±2.6 cm (non-SpO-AVMs, P= .25). All SpO-AVMs and 40 (27.0%) non-SpO-AVMs had a ruptured presentation (P=.006). A single draining veinwas observed in all SpO-AVMs and 39 (32.8%) non-SpO-AVMs (P=.01). Deep venous drainage was not observed in any SpO-AVMs, but in 81 (57.9%) non-SpO-AVMs (P = .04). Mean follow-up time was 37.0 ± 42.6 and 75.6 ± 161.7 mo in SpO-AVMand non-SpO-AVMs patients, respectively. Of the 2 SpO-AVMpatientswith postobliteration follow-up, 1 experienced recanalization. From a 672-patient cohort, the incidence of SpO over 28 961 patient years was 0.014%.

CONCLUSION: SpO-AVMs have an annual incidence rate of approximately 0.014% and tend to present with rupture, a single draining vein, and superficial venous drainage. Expectation of SpO for untreated AVMs is not justified, and patients should anticipate life-long hemorrhagic risk for untreated AVMs.

Automatic volumetry of cerebrospinal fluid and brain volume in severe paediatric hydrocephalus, implementation and clinical course after intervention

Acta Neurochirurgica (2020) 162:23–30

In childhood hydrocephalus, both the amount of cerebrospinal fluid and the brain volume are relevant for the prognosis of the development and for therapy monitoring. Since classical planar measurements of ventricular size are subject to strong limitations, imprecise and neglect brain volume, 3D volumetry is most desirable. We used and evaluated the robust segmentation algorithms of the freely available FSL-toolbox in paediatric hydrocephalus patients before and after specific therapy.

Methods Retrospectively 76 pre- and postoperative high-resolution T2-weighted MRI sequences (true FISP, 1 mm isovoxel) were analyzed in 38 patients with paediatric hydrocephalus (mean 4.4 ± 5.1 years) who underwent surgical treatment (ventriculoperitoneal (VP) shunt n = 22, endoscopic third ventriculostomy (ETV) n = 16). After preprocessing, the 3D-datasets were skull stripped to estimate the inner skull surface. Following, a 2 class segmentation into different tissue types (brain matter and CSF) was performed. The volumes of CSF and brain were calculated.

Results The method could be implemented in an automated fashion in all 76MRIs. In the VP shunt cohort, the amount of CSF (p < 0.001) decreased. Consecutively brain volume increased significantly (p < 0.001). Following ETV, CSF volume (p = 0.019) decreased significantly (p = 0.012) although the reduction was less pronounced than after shunt implantation. Brain volume expanded (p = 0.02).

Conclusion A reliable automated segmentation of CSF and brain could be performed with the implemented algorithm. The method was able to track changes after therapy and detected significant differences in CSF and brain volumes after shunting and after ETV.

Disruption of Frontal Aslant Tract Is Not Associated with Long-Term Postoperative Language Deficits

World Neurosurg. (2020) 133:192-195

The frontal aslant tract (FAT) is a white matter fiber pathway connecting the superior frontal gyrus to the Broca area. This tract in the dominant hemisphere has been shown to play a role in speech initiation and production, and direct subcortical stimulation can induce stuttering and speech arrest in a patient. However, controversy remains as to whether disruption of this pathway will lead to a permanent language deficit and if it is even necessary to map this tract during tumor resections of the dominant frontal lobe.

CASE DESCRIPTION: Here, we report a case of a patient with a lower-grade diffuse glioma invading the dominant FAT that was removed with an asleep craniotomy. In the immediate postoperative state, the patient had a transcortical motor dysphasia and was unable to initiate speech. These immediate language deficits quickly recovered, and the patient was neurologically intact at the time of discharge a few days after surgery.

CONCLUSIONS: Given the high likelihood for a complete neurologic recovery including transient aphasia, we propose that awake mapping for the purpose of identifying the dominant FAT is unnecessary during tumor resection and that disruption of this tract is not associated with any long-term language deficits.

Perioperative complications with multilevel anterior and posterior cervical decompression and fusion

J Neurosurg Spine 32:9–14, 2020

Cervical spondylotic myelopathy (CSM) is a progressive degenerative pathology that frequently affects older individuals and causes spinal cord compression with symptoms of neck pain, radiculopathy, and weakness. Anterior decompression and fusion is the primary intervention to prevent neurological deterioration; however, in severe cases, circumferential decompression and fusion is necessary. Published data regarding perioperative morbidity associated with these complex operations are scarce. In this study, the authors sought to add to this important body of literature by documenting a large single-surgeon experience of single-session circumferential cervical decompression and fusion.

METHODS A retrospective analysis was performed to identify intended single-stage anterior-posterior or posterioranterior- posterior cervical spine decompression and fusion surgeries performed by the primary surgeon (V.C.T.) at Rush University Medical Center between 2009 and 2016. Cases in which true anterior-posterior cervical decompression and fusion was not performed (i.e., those involving anterior-only, posterior-only, or delayed circumferential fusion) were excluded from analysis. Data including standard patient demographic information, comorbidities, previous surgeries, and intraoperative course, along with postoperative outcomes and complications, were collected and analyzed. Perioperative morbidity was recorded during the 90 days following surgery.

RESULTS Seventy-two patients (29 male and 43 female, mean age 57.6 years) were included in the study. Fourteen patients (19.4%) were active smokers, and 56.9% had hypertension, the most common comorbidity. The most common clinical presentation was neck pain in 57 patients (79.2%). Twenty-three patients (31.9%) had myelopathy, and 32 patients (44.4%) had undergone prior cervical spine surgery. Average blood loss was 613 ml. Injury to the vertebral artery was encountered in 1 patient (1.4%). Recurrent laryngeal nerve palsy was observed in 2 patients (2.8%). Two patients (2.8%) had transient unilateral hand grip weakness. There were no permanent neurological deficits. Dysphagia was encountered in 45 patients (62.5%) postoperatively, with 23 (32%) requiring nasogastric parenteral nutrition and 9 (12.5%) patients ultimately undergoing percutaneous endoscopic gastrostomy (PEG) placement. Nine of the 72 patients required a tracheostomy. The incidence of pneumonia was 6.9% (5 patients) overall, and 2 of these patients were in the tracheostomy group. Superficial wound infections occurred in 4 patients (5.6%). Perioperative death occurred in 1 patient. Reoperation was necessary in 10 patients (13.9%). Major perioperative complications (permanent neurological deficit, vascular injury, tracheostomy, PEG tube, stroke, or death) occurred in 30.6% of patients. The risk of minor perioperative complications (temporary deficit, dysphagia, deep vein thrombosis, pulmonary embolism, urinary tract infection, pneumonia, or wound infection) was 80.6%.

CONCLUSIONS Single-session anterior-posterior cervical decompression and fusion is an inherently morbid operation required in select patients with cervical spondylotic myelopathy. In this large single-surgeon series, there was a major perioperative complication risk of 30.6% and minor perioperative complication risk of 80.6%. This overall elevated risk for postoperative complications must be carefully considered and discussed with the patient preoperatively. In some situations, shared decision making may lead to the conclusion that a procedure of lesser magnitude may be more appropriate.

Ventriculoperitoneal shunt in treating of idiopathic normal pressure hydrocephalus—single-center study

Acta Neurochirurgica (2020) 162:1–7

Idiopathic normal pressure hydrocephalus (iNPH) is the only variant of dementia disorders possibly treatable by neurosurgical intervention. iNPH is a neurodegenerative condition clinically characterized by gait ataxia, urinary incontinence, and memory disturbance. We present one of the largest single-center studies, which was designed to prove efficacy of our low-pressure setting of gravitational valve at all three symptoms of iNPH and to find statistically significant cut-off time for best clinical improvement according to the duration of symptoms.

Methods Sixty-one consecutive patients (mean age 74.9 ± 5.3) with iNPH were prospectively observed from the time of surgery with minimal 6 months follow-up. All patients underwent implantation of the same type of gravitational valve with the same setting—pro GAV with low opening pressure at 5 cm H2O—and were operated by the same team of 2 neurosurgeons. We statistically evaluated gait disturbance, psychological changes, and incontinence preoperatively and at 6 months after surgery and timing of the surgery according to the duration of symptoms and to the age.

Results Paired t test showed a statistically significant increase in MMSE, a statistically significant decrease in 10-m walk test and 360 deg. rotation test (p < 0.0001). The correlation among the change of the MMSE, the walk test, and the rotation test, and the age and time of symptoms’ duration was verified by Pearson’s correlation coefficient. Pearson’s correlation coefficient showed a medium strong correlation between the change of MMSE and the time of symptoms (r = − 0.580; p < 0.0001) and between the change of the number of steps and the time of symptoms (r = 0.517, p < 0.0001). There was a statistically significant weak (poor) correlation between the change of the walk test and the time of symptoms (r = 0.351, p = 0.006). All 3 ROC tests confirmed optimal cut-off for the best improvement of symptoms as 9.5 months of the symptom duration.

Conclusions We proved statistical significant optimal cut-off for the best improvement of the symptoms as 9.5 months of the symptom duration. This study also confirmed successful treatment of iNPH with VP shunting using low pressure setting of gravitational valve with overall improvement in 75% and low over drainage complications in 5%. We proved statistically significant increase in MMSE, decrease in 10 m walk test and number of steps test, p < 0.0001.

Use of Vycor Tubular Retractors in the Management of Deep Brain Lesions

World Neurosurg. (2020) 133:283-290

Traditional manual retraction to access deep-seated brain lesions has been associated with complications related to vascular compromise of cerebral tissue. Various techniques have been developed over time to minimize injury, such as self-sustaining retractors, neuronavigation, and endoscopic approaches. Recently, tubular retractors, such as the ViewSite Brain Access System (VBAS), have been developed to reduce mechanical damage from retraction by dispersing the force of the retractor radially over the parenchyma. Therefore, we sought to review the current literature to accurately assess the indications, benefits, and complications associated with use of VBAS retractors.

METHODS: A literature search for English articles published between 2005 and 2019 was performed using the MEDLINE database archive with the search terminology “Vycor OR ViewSite OR Brain-Access-System NOT glass.” The VBAS website was also examined. Only articles detailing neurosurgical procedures using the VBAS tubular retractor system alone, or in combination with other retractors, were included. Postoperative morbidity and mortality were analyzed to estimate complications linked to using the retractor.

RESULTS: Twelve publications (106 patients) met the inclusion criteria. The VBAS retractor was used for tumor resections, hematoma evacuations, cyst removal, foreign body extractions, and lesion resection in toxoplasmosis and multiple sclerosis. These cases were subdivided into groups based on lesion location, size, and resection volume for further analysis. Gross total resection was achieved in 63% of tumor excisions, and subtotal resection was achieved in 37%. Hematoma evacuation was successful in all cases. There were 3 shortterm postoperative complications linked to the retractor, with an overall complication rate of 2.8%. –

CONCLUSIONS: This report is the first formal assessment of the VBAS, highlighting technical considerations of the retractor from the surgeon’s perspective, patient outcomes, and complications. The retractor is a safe and efficacious tubular retraction system that can be used for tumor biopsy and resection, colloid cyst removal, hematoma evacuation, and removal of foreign bodies. However, further randomized controlled trials are indicated to accurately assess complication rates and outcomes.

Cavernous sinus aneurysms: risk of growth over time and risk factors

J Neurosurg 132:22–26, 2020

Cavernous internal carotid artery (ICA) aneurysms are frequently diagnosed incidentally and the benign natural history of these lesions is well known, but there is limited information assessing the risk of growth in untreated patients. The authors sought to assess and analyze risk factors in patients with cavernous ICA aneurysms and compare them to those of patients with intracranial berry aneurysms in other locations.

METHODS Data from consecutive patients who were diagnosed with a cavernous ICA aneurysm were retrospectively reviewed. The authors evaluated patients for the incidence of cavernous ICA aneurysm growth and rupture. In addition, the authors analyzed risk factors for cavernous ICA aneurysm growth and compared them to risk factors in a population of patients diagnosed with intracranial berry aneurysms in locations other than the cavernous ICA during the same period.

RESULTS In 194 patients with 208 cavernous ICA aneurysms, the authors found a high risk of aneurysm growth (19.2% per patient-year) in patients with large/giant aneurysms. Size was significantly associated with higher risk of growth. Compared to patients with intracranial berry aneurysms in other locations, patients with cavernous ICA aneurysms were significantly more likely to be female and have a lower incidence of hypertension.

CONCLUSIONS Aneurysms of the cavernous ICA are benign lesions with a negligible risk of rupture but a definite risk of growth. Aneurysm size was found to be associated with aneurysm growth, which can be associated with new onset of symptoms. Serial follow-up imaging of a cavernous ICA aneurysm might be indicated to monitor for asymptomatic growth, especially in patients with larger lesions.

 

Lumbar disc extrusions reduce faster than bulging discs due to an active role of macrophages in sciatica

Acta Neurochirurgica (2020) 162:79–85

This retrospective observational histological study aims to associate the size and type of disc herniation with the degree of macrophage infiltration in disc material retrieved during disc surgery in patients with sciatica.

Methods Disc tissue of 119 sciatica patients was embedded in paraffin and stained with hematoxylin and CD68. Tissue samples were categorized as mild (0–10/cm2), moderate (10–100/cm2), and considerable (> 100/cm2) macrophage infiltration. All 119 patients received an MRI at baseline, and 108 received a follow-up MRI at 1-year. MRIs were reviewed for the size and type of the disc herniations, and for Modic changes in the vertebral endplates.

Results Baseline characteristics and duration of symptoms before surgery were comparable in all macrophage infiltration groups. The degree of macrophage infiltration was not associated with herniation size at baseline, but significantly associated with reduction of size of the herniated disc at 1-year post surgery. Moreover, the degree of macrophage infiltration was higher in extrusion in comparison with bulging (protrusion) of the disc. Results were comparable in patients with and without Modic changes.

Conclusion Macrophage infiltration was positively associated with an extruded type of disc herniation as well as the extent of reduction of the herniated disc during 1-year follow-up in patients with sciatica. This is an indication that the macrophages play an active role in reducing herniated discs. An extruded disc herniation has a larger surface for the macrophages to adhere to, which leads to more size reduction.

Stroke Thrombectomies Using ADAPT With Increasing Aspiration Catheter Size

Neurosurgery 86:61–70, 2020

Endovascular thrombectomy is currently the standard of care for acute ischemic stroke (AIS). Although earlier trials on endovascular thrombectomy were performed using stent retrievers, recently completed the contact aspiration vs stent retriever for successful revascularization (ASTER) and a comparison of direct aspiration versus stent retriever as a first approach (COMPASS) trials have shown the noninferiority of direct aspiration.

OBJECTIVE: To report the largest experience withADAPT thrombectomy and compare the impact of advancement in reperfusion catheter technologies on outcomes.

METHODS:We reviewed a retrospective database of AIS patients who underwent ADAPT thrombectomy between January 2013 and November 2017 at the Medical University of South Carolina. Demographics and baseline characteristics, technical variables, and radiological and clinical outcomes were reviewed.

RESULTS: Among 510 patients (mean age: 67.7, 50.6% females), successful recanalization at first pass was achieved in 61.8%, and with aspiration only in 77.5%.Mean procedure time was 27.4 min, and the rate of good outcomes (mRS 0-2) at 90 d was 42.9%. The rate of recanalization with aspiration only was significantly higher, and procedure timewas significantly lower in patients treated with larger catheters (ACE 064 and ACE 068) compared to smaller catheters (5MAX and ACE, P<.05). Therewere no differences in complication rates or postoperative parenchymal hemorrhage across groups (P > .05); however, use of ACE 068 was an independent predictor of good outcomes at 90 d on multivariate regression analysis (odds ratio = 1.6, P< .05).

CONCLUSION: Refinement of ADAPT thrombectomy by incorporating reperfusion catheters with higher inner diameters and thus higher aspiration forces is associated with better outcomes, shorter procedure times, and lower likelihood of using additional devices without impacting complication rates.