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Endoscope- versus microscope-integrated near-infrared indocyanine green videoangiography in aneurysm surgery

J Neurosurg 131:1413–1422, 2019

The quality of surgical treatment of intracranial aneurysms is determined by complete aneurysm occlusion while preserving blood flow in the parent, branching, and perforating arteries. For a few years, there has been a nearly noninvasive and cost-effective technique for intraoperative flow evaluation: microscope-integrated indocyanine green videoangiography (mICG-VA). This method allows for real-time information about blood flow in the aneurysm and the involved vessels, but its limitations are seen in the evaluation of structures located in the depth of the surgical field, especially through small craniotomies. To compensate for these drawbacks, an endoscope-integrated ICG-VA (eICG-VA) was developed. The objective of the present study was to assess the use of eICG-VA in comparison with mICG-VA for intraoperative blood flow evaluation.

METHODS In the period between January 2011 and January 2015, 216 patients with a total of 248 intracranial saccular aneurysms were surgically treated in the Department of Neurosurgery of Saarland University Medical Center in Homburg/Saar, Germany. During 95 surgeries in 88 patients with a total of 108 aneurysms, intraoperative evaluation was performed with both eICG-VA and mICG-VA. After clipping, evaluation of complete aneurysm occlusion and flow in the parent, branching, and perforating arteries was performed using both methods. Intraoperative applicability of each technique was compared with the other and with postoperative digital subtraction angiography as a standard evaluation technique.

RESULTS Evaluation of completeness of aneurysm occlusion and of flow in the parent, branching, and perforating arteries was more successful with eICG-VA than with mICG-VA, especially for aneurysm neck assessment (88.9% vs 69.4%). For 63.9% of the aneurysms (n = 69), both methods were equivalent, but in 30.6% of the cases (n = 33), the eICG-VA provided better results for evaluating the post-clipping situation. In 4.6% of these aneurysms (n = 5), the information given by the additional endoscope considerably changed the surgical procedure. Thus, one residual aneurysm (0.9%), two neck remnants (1.9%), and two branch occlusions (1.9%) could be prevented. Nevertheless, two incomplete aneurysm occlusions (1.9%) and six neck remnants (5.6%) were revealed by postoperative digital subtraction angiography.

CONCLUSIONS Endoscope-integrated ICG-VA seems to be an improvement that might increase the quality of aneurysm surgery by providing additional information. It offers higher illumination, magnification, and an extended viewing angle. Its main advantage is its ability to assess deep-seated aneurysms, especially through small craniotomies, but further studies are required.

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Exclusive Endoscopic Occipital Transtentorial Approach for Pineal Region Tumors

World Neurosurg. (2019) 131:167-173

Removal of pineal region tumors, which are deeply placed and encircled by intricate neurovascular structures, is challenging to neurosurgeons. The aim of this study was to present our experience with the exclusive endoscopic occipital transtentorial approach (EEOTA) used for removal of pineal region tumors.

METHODS: A retrospective review was performed of patients who underwent surgery using the EEOTA to remove pineal region tumors from May 2016 to August 2018. The details of the EEOTA procedure were confirmed.

RESULTS: Five patients underwent surgery via the EEOTA for treatment of pineal region tumors. In all cases, it was possible to perform the EEOTA less invasively through a keyhole craniotomy approximately 2.0e2.5 cm in size. The EEOTA produced an excellent view and provided natural and automatic orientation. There was essentially no blind spot in this procedure, even for the floor or ipsilateral wall of the third ventricle. Gross total resection was achieved in 4 cases. In the patient with atypical teratoid rhabdoid tumor, we abandoned gross total resection because of a hardened adhesion to the tectum and the great cerebral vein and its tributaries. Two patients presented with transient upper gaze palsy immediately after surgery but experienced complete recovery during the follow-up period.

CONCLUSIONS: The EEOTA is a very promising technique for removal of pineal region tumors and has the potential for extensive and routine application for surgeons familiar with endoscopic surgery.

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A wearable mixed-reality holographic computer for guiding external ventricular drain insertion at the bedside

J Neurosurg 131:1599–1606, 2019

The goal of this study was to explore the feasibility and accuracy of using a wearable mixed-reality holographic computer to guide external ventricular drain (EVD) insertion and thus improve on the accuracy of the classic freehand insertion method for EVD insertion. The authors also sought to provide a clinically applicable workflow demonstration.

METHODS Pre- and postoperative CT scanning were performed routinely by the authors for every patient who needed EVD insertion. Hologram-guided EVD placement was prospectively applied in 15 patients between August and November 2017. During surgical planning, model reconstruction and trajectory calculation for each patient were completed using preoperative CT. By wearing a Microsoft HoloLens, the neurosurgeon was able to visualize the preoperative CT-generated holograms of the surgical plan and perform EVD placement by keeping the catheter aligned with the holographic trajectory. Fifteen patients who had undergone classic freehand EVD insertion were retrospectively included as controls. The feasibility and accuracy of the hologram-guided technique were evaluated by comparing the time required, number of passes, and target deviation for hologram-guided EVD placement with those for classic freehand EVD insertion.

RESULTS Surgical planning and hologram visualization were performed in all 15 cases in which EVD insertion involved holographic guidance. No adverse events related to the hologram-guided procedures were observed. The mean ± SD additional time before the surgical part of the procedure began was 40.20 ± 10.74 minutes. The average number of passes was 1.07 ± 0.258 in the holographic guidance group, compared with 2.33 ± 0.98 in the control group (p < 0.01). The mean target deviation was 4.34 ± 1.63 mm in the holographic guidance group and 11.26 ± 4.83 mm in the control group (p < 0.01).

CONCLUSIONS This study demonstrates the use of a head-mounted mixed-reality holographic computer to successfully perform hologram-assisted bedside EVD insertion. A full set of clinically applicable workflow images is presented to show how medical imaging data can be used by the neurosurgeon to visualize patient-specific holograms that can intuitively guide hands-on operation. The authors also provide preliminary confirmation of the feasibility and accuracy of this hologram-guided EVD insertion technique.

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Management of recurrent intracranial aneurysms after coil embolization: a novel classification scheme based on angiography

J Neurosurg 131:1455–1461, 2019

Recurrent aneurysms after coil embolization remain a challenging issue. The goal of the present study was to report the authors’ experience with recurrent aneurysms after coil embolization and to discuss the radiographic classification scheme and recommended management strategy.

METHODS Aneurysm treatments from a single institution over a 6-year period were retrospectively reviewed. Ninetyseven aneurysms that recurred after initial coiling were managed during the study period. Recurrent aneurysms were classified into the following 5 types based on their angiographic characteristics: I, pure recanalization inside the aneurysm sac; II, pure coil compaction without aneurysm growth; III, new aneurysm neck formed without coil compaction; IV, new aneurysm neck formed with coil compaction; and V, newly formed aneurysm neck and sac.

RESULTS Aneurysm recurrences resulted in rehemorrhages in 6 cases (6.2%) of type III–V aneurysms, but in none of type I–II aneurysms. There was a significantly higher proportion of ophthalmic artery aneurysms and complex internal carotid artery aneurysms presenting as types I and II than presented as the other 3 types (63.3% vs 16.4%, p < 0.001). In contrast, for posterior communicating artery aneurysms and anterior communicating artery aneurysms, a higher proportion of type III–V aneurysms was observed than for the other 2 types, but without a significant difference in the multivariate model (56.7% vs 23.3%). In addition, giant (> 25 mm) aneurysms were more common among type I and II lesions than among type III and IV aneurysms (36.7% vs 9.0%, p = 0.001), which exhibited a higher proportion of small (< 10 mm) lesions (65.7% vs 13.3%, p < 0.001). A single reembolization procedure was sufficient to occlude 80.0% of type I recurrences and 83.3% of type II recurrences from coil compaction but only 65.6% of type III–V recurrences from aneurysm regrowth.

CONCLUSIONS Aneurysm size and location represent the determining factors of the angiographic recurrence types. Type I and II recurrences were safely treated by reembolization, whereas type III–V recurrences may be best managed surgically when technically feasible.

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Comparative Analysis of Subventricular Zone Glioblastoma Contact and Ventricular Entry During Resection in Predicting Dissemination, Hydrocephalus, and Survival

Neurosurgery, Volume 85, Issue 5, November 2019, Pages E924–E932

Ventricular entry during glioblastoma resection and tumor contact with the subventricular zone (SVZ) have both been shown to associate with development of hydrocephalus, leptomeningeal dissemination, distant parenchymal recurrence, and decreased survival. However, prior studies did not analyze these variables together in a single-patient population; therefore, it is unknown which is an independent predictor of these outcomes.

OBJECTIVE: To conduct a comparative outcome analysis of surgical ventricular entry and SVZ contact by glioblastoma in a retrospective cohort of 232 patients.

METHODS: Outcomes studied included hydrocephalus, leptomeningeal dissemination, distant tumor recurrences, and progression-free (PFS) and overall (OS) survival. The Cox proportional regression analyses were adjusted for age at diagnosis, preoperative Karnofsky performance status score, extent of resection, temozolomide and radiation treatments, and tumor molecular status (specifically, IDH1/2 mutation and MGMT promoter methylation).

RESULTS: Surgical ventricular entry, SVZ-contacting glioblastoma, hydrocephalus, leptomeningeal dissemination, and distant recurrences were observed in 85 (36.6%), 114 (49.1%), 19 (8.2%), 78 (33.6%), and 59 (25.4%) patients, respectively. Multivariate, adjusted analysis revealed SVZ tumor contact—but not ventricular entry—associated with hydrocephalus (hazard ratio, HR, 4.20 [1.13-15.7], P = .03), leptomeningeal dissemination (HR 1.93 [1.14-3.28], P = .01), PFS (HR 2.10 [1.53-2.88], P < .001), and OS (HR 1.90 [1.35-2.67], P < .001). Distant recurrences were not associated with either. No interaction between the 2 variables was statistically noted.

CONCLUSION: SVZ contact by glioblastoma was independently associated with the development of hydrocephalus, leptomeningeal dissemination, and decreased survival. SVZ tumor contact was associated with ventricular entry during surgical resections, which did not independently correlate with these outcomes.

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The foramen lacerum: surgical anatomy and relevance for endoscopic endonasal approaches

J Neurosurg 131:1571–1582, 2019

The foramen lacerum is a relevant skull base structure that has been neglected for many years. From the endoscopic endonasal perspective, the foramen lacerum is a key structure due to its location at the crossroad between the sagittal and coronal planes. The objective of this study was to provide a detailed investigation of the surgical anatomy of the foramen lacerum and its adjacent structures based on anatomical dissections and imaging studies, propose several relevant key surgical landmarks, and demonstrate the surgical technique for its full exposure with several illustrative cases.

METHODS Ten colored silicone-injected anatomical specimens were dissected using a transpterygoid approach to the foramen lacerum region in a stepwise manner. Five similar specimens were used for a comparative transcranial approach. The osseous anatomy was examined in 32 high-resolution multislice CT studies and 1 disarticulated skull. Representative cases were selected to illustrate the application of the findings.

RESULTS The pterygosphenoidal fissure is the synchondrosis between the lacerum process of the pterygoid bone and the floor of the sphenoid bone. It constantly converges with the posterior end of the vidian canal at a 45° angle, and its posterolateral end points directly to the lacerum foramen. The pterygoid tubercle separates the vidian canal from the pterygosphenoidal fissure, and forms the anterior wall of the lower part of the foramen lacerum. The lingual process, which forms the lateral wall of the foramen lacerum, was identified in 53 of 64 sides and featured an average height of 5 mm. The mandibular strut separates the foramen lacerum from the foramen ovale and had an average width of 5 mm.

CONCLUSIONS This study provides relevant surgical landmarks and a systematic approach to the foramen lacerum by defining anterior, medial, lateral, and inferior walls that may facilitate its safe exposure for effective removal of lesions while minimizing the risk of injury to the internal carotid artery.

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The transcallosal transchoroidal approach to the diencephalic-mesencephalic junction

Acta Neurochirurgica (2019) 161:2329–2334

Different approaches have to be considered for lesions of the diencephalic-mesencephalic junction based on the localization, extension of the lesion, and relationship to the ventricular system.

Method We present the case of a young lady who presented with a cavernoma of the junction of midbrain and diencephalon after an episode of hemorrhage. The microsurgical anatomy of the trans-callosal trans-choroidal approach for this lesion is described along with its advantages and limitations.

Conclusion The trans-choroidal approach allows adequate access to lesions of the diencephalic-mesencephalic junction that project into the third ventricle.

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Key anatomical landmarks for middle fossa surgery: a surgical anatomy study

J Neurosurg 131:1561–1570, 2019

Middle fossa surgery is challenging, and reliable surgical landmarks are essential to perform accurate and safe surgery. Although many descriptions of the middle fossa components have been published, a clinically practical description of this very complex anatomical region is lacking. Small structure arrangements in this area are often not well visualized or accurately demarcated with neuronavigation systems. The objective is to describe a “roadmap” of key surgical reference points and landmarks during middle fossa surgery to help the surgeon predict where critical structures will be located.

METHODS The authors studied 40 dry skulls (80 sides) obtained from the anatomical board at their institution. Measurements of anatomical structures in the middle fossa were made with a digital caliper and a protractor, taking as reference the middle point of the external auditory canal (MEAC). The results were statistically analyzed.

RESULTS The petrous part of the temporal bone was found at a mean of 16 mm anterior and 24 mm posterior to the MEAC. In 87% and 99% of the sides, the foramen ovale and foramen spinosum, respectively, were encountered deep to the zygomatic root. The posterior aspect of the greater superficial petrosal nerve (GSPN) groove was a mean of 6 mm anterior and 25 mm medial to the MEAC, nearly parallel to the petrous ridge. The main axis of the IAC projected to the root of the zygoma in all cases. The internal auditory canal (IAC) porus was found 5.5 mm lateral and 4.5 mm deep to the lateral aspect of the trigeminal impression along the petrous ridge (mean measurement values). A projection from this point to the middle aspect of the root of the zygoma, being posterior to the GSPN groove, could estimate the orientation of the IAC.

CONCLUSIONS In middle fossa approaches, the external acoustic canal is a reliable reference before skin incision, whereas the zygomatic root becomes important after the skin incision. Deep structures can be related to these 2 anatomical structures. An easy method to predict the location of the IAC in surgery is described. Careful study of the preoperative imaging is essential to adapt this knowledge to the individual anatomy of the patient.

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Microsurgical anatomy of the sagittal stratum

Acta Neurochirurgica (2019) 161:2319–2327

The sagittal stratum (SS) is a critical neural crossroad traversed by several white matter tracts that connect multiple areas of the ipsilateral hemisphere. Scant information about the anatomical organization of this structure is available in literature. The goal of this study was to provide a detailed anatomical description of the SS and to discuss the functional implications of the findings when a surgical approach through this structure is planned.

Methods Five formalin-fixed human brains were dissected under the operating microscope by using the fiber dissection technique originally described by Ludwig and Klingler.

Results The SS is a polygonal crossroad of associational fibers situated deep on the lateral surface of the hemisphere, medial to the arcuate/superior longitudinal fascicle complex, and laterally to the tapetal fibers of the atrium. It is organized in three layers: a superficial layer formed by the middle and inferior longitudinal fascicles, a middle layer corresponding to the inferior frontooccipital fascicle, and a deep layer formed by the optic radiation, intermingled with fibers of the anterior commissure. It originates posteroinferiorly to the inferior limiting sulcus of the insula, contiguous with the fibers of the temporal stem, and ends into the posterior temporo-occipito-parietal cortex.

Conclusion The white matter fiber dissection reveals the tridimensional architecture of the SS and the relationship between its fibers. A detailed understanding of the anatomy of the SS is essential to decrease the operative risks when a surgical approach within this area is undertaken.

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Hearing preservation in vestibular schwannoma surgery via retrosigmoid transmeatal approach

Acta Neurochirurgica (2019) 161:2265 –2269

Advances in various diagnostic and/or treatment modalities, including radiological imaging, neuromonitoring, and microsurgical techniques, have resulted in treatments of vestibular schwannomas being aimed at preserving facial and hearing functions while achieving optimal tumor control.

Method We describe our surgical technique for hearing preservation in vestibular schwannoma surgery.

Conclusion The retrosigmoid transmeatal approach under continuous neuromonitoring (auditory brainstem response, cochlear nerve action potentials, and continuous facial nerve monitoring) enables gross-total resection of vestibular schwannomas, while preserving hearing and facial functions. Radiological assessment and microsurgical techniques, such as meticulous tumor dissection, are also essential for functional preservation with sufficient tumor removal.

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Chiari malformation and syringomyelia

J Neurosurg Spine 31:619–628, 2019

Chiari malformation was first described over a century ago, and consists of posterior fossa anomalies that generally share the feature of cerebellar tonsillar descent through the foramen magnum. Our understanding of this disorder was initially based on autopsy studies, and has been greatly enhanced by the advent of MRI.

The surgical management of Chiari anomalies has also evolved in a parallel fashion. Although the exact surgical technique varies among individual surgeons, the goals of surgery remain constant and consist of relieving brainstem compression and cranial nerve distortion, restoring the normal flow of CSF across the foramen magnum, and reducing the size of any associated syrinx cavity. Syrinx cavities are most commonly associated with Chiari anomalies, yet primary spinal syringomyelia (PSS) can be caused by traumatic, infectious, degenerative, and other etiologies that cause at least a partial CSF flow obstruction in the spinal subarachnoid space. As with syringomyelia associated with Chiari anomalies, the main goal of PSS surgery is to reestablish CSF flow across the area of obstruction. In addition to MRI, myelography with CT can be very helpful in the evaluation and management of these patients by identifying focal regions of CSF obstruction that may be amenable to surgical intervention.

Future directions for the treatment of Chiari anomalies and syringomyelia include the application of advanced imaging techniques, more widespread use of genetic evaluation, large-scale outcome studies, and the further refinement of surgical technique.

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Gamma Knife Radiosurgery for Multiple Sclerosis-Associated Trigeminal Neuralgia

 

Neurosurgery 85:E933–E939, 2019

Trigeminal neuralgia in the setting of multiple sclerosis (MS-TN) is a challenging condition to manage that is commonly treated with Gamma Knife radiosurgery (GKRS; Elekta AB). However, data regarding the efficacy of this treatment are somewhat limited, particularly for repeat GKRS.

OBJECTIVE: To report outcomes of GKRS for MS-TN from a cohort study.

METHODS: Retrospective review of our GKRS database identified 77 cases of unilateral MS-TN (UMSTN) in 74 patients treated with GKRS between 2001 and 2016, with 37 cases undergoing repeat GKRS. Background medical history, treatment outcomes and complications, and dosimetric data were obtained by retrospective chart reviews and telephone interviews.

RESULTS:Eighty two percent of UMSTN cases achieved Barrow Neurological Institute (BNI) IIIb or better pain relief following initial GKRS for a median duration of 1.1 yr. Estimated rates ofpainreliefat1,3,and5yr were 51,39,and29% respectively.Eighty-eightpercentachieved BNI IIIb or better pain relief after repeat GKRS for a median duration of 4.0 yr. Estimated rates of pain relief at 1 and 3 yr were 70 and 54%, respectively. Median doses for initial and repeat GKRS were 85 and 80 Gy to the 100% isodose line, respectively. Those with MS-TN had a shorter duration of BNI IIIb or better pain relief after initial (4.6 vs 1.1 yr), but not repeat GKRS (3.8 vs 4.0 yr) compared to a historical cohort from our institution.

CONCLUSION: GKRS is an effective, well-tolerated treatment for patientswith MS-TN. More durable relief is often achieved with repeat GKRS.

 

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Analysis of Wide-Neck Aneurysms in the Barrow Ruptured Aneurysm Trial

Neurosurgery, Volume 85, Issue 5, November 2019, Pages 622–631

Ruptured wide-neck aneurysms (WNAs) are difficult to treat and few publications have compared clipping to coiling.

OBJECTIVE: To determine, using Barrow Ruptured Aneurysm Trial (BRAT) data: (1) How many aneurysms had a wide neck? (2) Did wide-neck status influence treatment? (3) How did clipping compare to coiling for WNAs?

METHODS: A post hoc analysis was conducted of saccular WNAs in the BRAT. A WNA was defined as maximum neck width ≥ 4 mm or maximum aneurysm dome-diameter–toneck-width ratio < 2. Both intent-to-treat and as-treated analyses were performed.

RESULTS: Of the 327 patients analyzed, 177 (54.1%) had a WNA. WNAs were more likely to occur in older patients (P = .03) with worse presenting clinical grade (P = .02), were more likely to arise from the middle cerebral artery, basilar tip, or internal carotid artery other than the junction with the posterior communicating artery (P = .001) and were associated with worse clinical outcomes at all time points (P ≤ .01). WNAs were equally distributed in assigned treatment groups (clip 56.6% vs coil 51.8%; P = .38), but were overrepresented in the actual clipping group (clip 62.4% vs coil 37.6%, P < .001). Most patients (76.7%) in the coil-to-clip crossover group had a WNA. Comparing clipping to coiling, there was no difference in clinical outcomes at any time point in either analysis (P ≥ .33). The aneurysm obliteration rate was lower (P< .001) and the retreatment rate higher (P< .001) in the actual coiling group.

CONCLUSION: Wide-neck status significantly impacted treatment strategy in the BRAT, favoring clipping. Clipping and coiling of ruptured WNAs resulted in statistically similar long-term clinical outcomes.

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Growth prediction in asymptomatic meningiomas: the utility of the AIMSS score

Acta Neurochirurgica (2019) 161:2233–2240

Management of asymptomatic meningiomas represents a challenge due to the absence of a solid consensus on which is the best management strategy. There are various known factors predicting meningiomas growth risk. However, the Asian Intracranial Meningioma Scoring System (AIMSS) is the only described score to quantify such risk thus emerging as a potential tool for management decisions. This study aims to validate this score on our series of asymptomatic meningiomas.

Method We performed a retrospective review of asymptomatic meningiomas diagnosed at our institution between January 2008 and October 2016 and followed by an annual cerebral Magnetic Resonance Imaging (MRI). For each lesion, the AIMSS score was calculated thus classifying them in low (0–2), intermediate (3–6) or high risk (7–11) of rapid growth (>2cm 3 /year). We investigated the correlation between the expected Average Growth Rate (AGR) according to the score and the one obtained in our study. The mean growth velocity over the different risk groups was also compared.

Results Overall, 69 asymptomatic meningiomas found incidentally in 46 patients were included in the study; 31 were assigned to the low-risk group, 34 to the intermediate-risk group and 4 to the high-risk group. Attending to the AGR, 0% showed rapid growth in the low-risk group, 12% in the intermediate-risk group, and 25% in the high-risk group. The mean growth velocity showed a significant difference over the different risk groups (p < 0,001).

Conclusions According to our finding, the AIMSS score is a valid tool to estimate the risk of rapid growth of asymptomatic meningiomas. It is especially useful distinguishing between low- and intermediate-risk meningiomas. This feature would allow physicians to adjust the periodicity of radiological and clinical controls. Adding more known risk factors of rapid growth to the score might improve its predictive capabilities with the high-risk group.

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Comparing costs of microsurgical resection and stereotactic radiosurgery for vestibular schwannoma

J Neurosurg 131:1395–1404, 2019

Given rising scrutiny of healthcare expenditures, understanding intervention costs is increasingly important. This study aimed to compare and characterize costs for vestibular schwannoma (VS) management with microsurgery and radiosurgery to inform practice decisions and appraise cost reduction strategies.

METHODS In conjunction with medical records, internal hospital financial data were used to evaluate costs. Total cost was divided into index costs (costs from arrival through discharge for initial intervention) and follow-up costs (through 36 months) for 317 patients with unilateral VSs undergoing initial management between June 2011 and December 2015. A retrospective matched cohort based on tumor size with 176 patients (88 undergoing each intervention) was created to objectively compare costs between microsurgery and radiosurgery. The full sample of 203 patients treated with resection and 114 patients who underwent radiosurgery was used to evaluate a broad range of outcomes and identify cost contributors within each intervention group.

RESULTS Within the matched cohort, average index costs were significantly higher for microsurgery (100% by definition, because costs are presented as a percentage of the average index cost for the matched microsurgery group; 95% CI 93–107) compared to radiosurgery (38%, 95% CI 38–39). Microsurgery had higher average follow-up costs (1.6% per month, 95% CI 0.8%–2.4%) compared to radiosurgery (0.5% per month, 95% CI 0.4%–0.7%), largely due to costs incurred in the initial months after resection. A major contributor to total cost and cost variability for both resection and radiosurgery was the need for additional interventions in the follow-up period, which were necessary due to complications or persistent functional deficits. Although tumor size was not associated with increased total costs for radiosurgery, linear regression analysis demonstrated that, for patients who underwent microsurgery, each centimeter increase in tumor maximum diameter resulted in an estimated increase in total cost of 50.2% of the average index cost of microsurgery (95% CI 34.6%–65.7%) (p < 0.001, R 2 = 0.17). There were no cost differences associated with the proportion of inpatient days in the ICU or with specific surgical approach for patients who underwent resection.

CONCLUSIONS This study is the largest assessment to date based on internal cost data comparing VS management with microsurgery and radiosurgery. Both index and follow-up costs are significantly higher when tumors were managed with resection compared to radiosurgery. Larger tumors were associated with increased resection costs, highlighting the incremental costs associated with observation as the initial management.

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Risk of First Hemorrhage of Brain Arteriovenous Malformations During Pregnancy

Neurosurgery 85:E806–E814, 2019

Recommendations on the management of brain arteriovenous malformations (bAVM) with respect to pregnancy are based upon conflicting literature.

OBJECTIVE: To systematically review the reported risk and annualized rate of first intracranial hemorrhage (ICH) from bAVM during pregnancy and puerperium.

METHODS: MEDLINE, EMBASE, and Scopus databases were searched for relevant articles in English published before April 2018. Studies providing a quantitative risk of ICH in bAVM during pregnancy were eligible.

RESULTS: From 7 initially eligible studies, 3 studies met the criteria for providing quanti- tative risk of first ICH bAVM during pregnancy. Data from 47 bAVM ICH during pregnancy across 4 cohorts were extracted for analysis. Due to differences in methodology and defini- tions of exposure period, it was not appropriate to combine the cases. The annualized risk of first ICH during pregnancy for these 4 cohorts was 3.0% (95% confidence interval [CI]: 1.7- 5.2%); 3.5% (95% CI: 2.4-4.5%); 8.6% (95% CI: 1.8-25%); and 30% (95% CI: 18-49%). Only the last result from the last cohort could be considered significantly increased in comparison with the nonpregnant period (relative rate 6.8, 95% CI: 3.6-13). The limited number of eligible studies and variability in results highlighted the need for enhanced rigor of future research.

CONCLUSION: There is no conclusive evidence of an increased risk of first hemorrhage during pregnancy from bAVM. Because advice to women with bAVM may influence the management of pregnancy or bAVM with significant consequences, we believe that a retrospective multicenter, case crossover study is urgently required.

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Riskier-than-expected occlusive treatment of ruptured posterior communicating artery aneurysms

J Neurosurg 131:1269–1277, 2019

Occlusive treatment of posterior communicating artery (PCoA) aneurysms has been seen as a fairly uncomplicated procedure. The objective here was to determine the radiological and clinical outcome of patients after PCoA aneurysm rupture and treatment and to evaluate the risk factors for impaired outcome.

METHODS In a retrospective clinical follow-up study, data were collected from 620 consecutive patients who had been treated for ruptured PCoA aneurysms at a single center between 1980 and 2014. The follow-up was a minimum of 1 year after treatment or until death.

RESULTS Of the 620 patients, 83% were treated with microsurgical clipping, 8% with endovascular coiling, 2% with the two procedures combined, 1% with indirect surgical methods, and 6% with conservative methods. The most common procedural complications were treatment-related brain infarctions (15%). The occurrence of artery occlusions (10% microsurgical, 8% endovascular) was higher than expected. Most patients made a good recovery at 1 year after aneurysmal subarachnoid hemorrhage (modified Rankin Scale [mRS] score 0–2: 386 patients [62%]). A fairly small proportion of patients were left severely disabled (mRS score 4–5: 27 patients [4%]). Among all patients, 20% died during the 1st year. Independent risk factors for an unfavorable outcome, according to the multivariable analysis, were poor preoperative clinical condition, intracerebral or subdural hematoma due to aneurysm rupture, age over 65 years, artery occlusion on postoperative angiography, occlusive treatment–related ischemia, delayed cerebral vasospasm, and hydrocephalus requiring a shunt.

CONCLUSIONS Even though most patients made a good recovery after PCoA aneurysm rupture and treatment during the 1st year, the occlusive treatment–related complications were higher than expected and caused morbidity even among initially good-grade patients. Occlusive treatment of ruptured PCoA aneurysms seems to be a high-risk procedure, even in a high-volume neurovascular center.

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Surgical outcomes after reoperation for recurrent non–skull base meningiomas

J Neurosurg 131:1179–1187, 2019

Recurrent meningiomas are primarily managed with radiation therapy or repeat resection. Surgical morbidity after reoperation for recurrent meningiomas is poorly understood. Thus, the objective of this study was to report surgical outcomes after reoperation for recurrent non–skull base meningiomas.

METHODS A retrospective review of patients was performed. Inclusion criteria were patients with recurrent meningioma who had prior resection and supratentorial non–skull base location. Univariate and multivariate logistic regression and recursive partitioning analysis were used to identify risk factors for surgical complications.

RESULTS The authors identified 67 patients who underwent 111 reoperations for recurrent supratentorial non–skull base meningiomas. The median age was 53 years, 49% were female, and the median follow-up was 9.8 years. The most common presenting symptoms were headache, weakness, and seizure. The WHO grade after the last reoperation was grade I in 22% of cases, grade II in 51%, and grade III in 27%. The tumor grade increased at reoperation in 22% of cases. Tumors were located on the convexity (52%), parasagittal (33%), falx (31%), and multifocal (19%) locations. Tumors involved the middle third of the sagittal plane in 52% of cases. In the 111 reoperations, 48 complications occurred in 32 patients (48%). There were 26 (54%) complications requiring surgical intervention. There was no perioperative mortality. Complications included neurological deficits (14% total, 8% permanent), wound dehiscence/infection (14%), and CSF leak/pseudomeningocele/hydrocephalus (9%). Tumors that involved the middle third of the sagittal plane (OR 6.97, 95% CI 1.5–32.0, p = 0.006) and presentation with cognitive changes (OR 20.7, 95% CI 2.3–182.7, p = 0.001) were significantly associated with complication occurrence on multivariate analysis. The median survival after the first reoperation was 11.5 years, and the 2-, 5-, and 10-year Kaplan-Meier survival rates were 91.0%, 68.8%, and 50.0%, respectively.

CONCLUSIONS Reoperation for recurrent supratentorial non–skull base meningioma is associated with a high rate of complications. Patients with cognitive changes and tumors that overlap the middle third of the sagittal plane are at increased risk of complications. Nevertheless, excellent long-term survival can be achieved without perioperative mortality.

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Transcavernous sinus pituitary gland transposition

Acta Neurochirurgica (2019) 161:2123–2127

Pituitary transposition preserving gland function is possible when approaching superior clival region tumors. Clinical experience along with detailed anatomical knowledge makes this technique safe and effective.

Method We present a step by step description of our technique based on the most recent anatomical references to get a pituitary transposition through the different compartments of the cavernous sinus. By this technique, we achieve minor gland manipulation and a better surgical view of this area. We support this technique with an anatomical analysis on cadaveric specimens and clarifying dissection images.

Conclusions Transcavernous sinus pituitary gland transposition is an easily feasible technique and allows gland shifting preserving pituitary function.

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Does lumbar drainage reduce postoperative cerebrospinal fluid leak after endoscopic endonasal skull base surgery? A prospective, randomized controlled trial

J Neurosurg 131:1172–1178, 2019

Based on a null hypothesis that the use of short-term lumbar drainage (LD) after endoscopic endonasal surgery (EES) for intradural pathology does not prevent postoperative CSF leaks, a trial was conducted to assess the effect of postoperative LD on postoperative CSF leak following standard reconstruction.

METHODS A prospective, randomized controlled trial of lumbar drain placement after endoscopic endonasal skull base surgery was performed from February 2011 to March 2015. All patients had 3-month follow-up data. Surgeons were blinded to which patients would or would not receive the drain until after closure was completed. An a priori power analysis calculation assuming 80% of power, 5% postoperative CSF leak rate in the no-LD group, and 16% in the LD group determined a planned sample size of 186 patients. A routine data and safety check was performed with every 50 patients being recruited to ensure the efficacy of randomization and safety. These interim tests were run by a statistician who was not blinded to the arms they were evaluating. This study accrued 230 consecutive adult patients with skull base pathology who were eligible for endoscopic endonasal resection. Inclusion criteria (high-flow leak) were dural defect greater than 1 cm2 (mandatory), extensive arachnoid dissection, and/or dissection into a ventricle or cistern. Sixty patients were excluded because they did not meet the inclusion criteria. One hundred seventy patients were randomized to either receive or not receive a lumbar drain.

RESULTS One hundred seventy patients were randomized, with a mean age of 51.6 years (range 19–86 years) and 38% were male. The mean BMI for the entire cohort was 28.1 kg/m 2 . The experimental cohort with postoperative LD had an 8.2% rate of CSF leak compared to a 21.2% rate in the control group (odds ratio 3.0, 95% confidence interval 1.2–7.6, p = 0.017). In 106 patients in whom defect size was measured intraoperatively, a larger defect was associated with postoperative CSF leak (6.2 vs 2.9 cm 2 , p = 0.03). No significant difference was identified in BMI between those with (mean28.4 ± 4.3 kg/m 2 ) and without (mean 28.1 ± 5.6 kg/m 2 ) postoperative CSF leak (p = 0.79). Furthermore, when patients were grouped based on BMI < 25, 25–29.9, and > 30 kg/m 2 , no difference was noted in the rates of CSF fistula (p =0.97).

CONCLUSIONS Among patients undergoing intradural EES judged to be at high risk for CSF leak as defined by the study’s inclusion criteria, perioperative LD used in the context of vascularized nasoseptal flap closure significantly reduced the rate of postoperative CSF leaks.

Clinical trial registration no.: NCT03163134 (clinicaltrials.gov). https://thejns.org/doi/abs/10.3171/2018.4.JNS172447

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