Category: Surgical technique

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Superior cerebellar artery–posterior cerebral artery bypass

Superior cerebellar artery–posterior cerebral artery bypass

J Neurosurg 118:1053–1057, 2013

Iatrogenic pseudoaneurysms are rare but serious complications of transsphenoidal surgery, and an iatrogenic pseudoaneurysm of the posterior cerebral artery (PCA) has been reported just once in the literature.

The authors encountered such a case with a new P1 segment PCA pseudoaneurysm after endoscopic transsphenoidal resection of a pituitary adenoma. The aneurysm proved ideal for a novel intracranial–intracranial bypass in which the superior cerebellar artery (SCA) was used as an in situ donor artery to revascularize the recipient P2 segment. The bypass allowed aneurysm trapping without causing ischemic stroke or neurological morbidity.

This case represents the first reported surgical treatment of an iatrogenic PCA pseudoaneurysm. Endovascular occlusion with coils was an option, but dolichoectatic morphology requires sacrifice of the P1 segment, with associated risks to the thalamoperforators and circumflex perforators. The SCA-PCA bypass was ideal because of low-flow demands. Like other in situ bypasses, it requires no dissection of extracranial arteries, no second incision for harvesting interposition grafts, and has a high likelihood of long-term patency. The SCA-PCA bypass is also applicable to fusiform SCA aneurysms requiring revascularization with trapping.

This case demonstrates a dangerous complication that results from the limited view of the posterolateral surgical field through the endoscope and the imprecision of endoscopic instruments.

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Amygdalohippocampotomy: surgical technique and clinical results

Amygdalohippocampotomy

J Neurosurg 118:1107–1113, 2013

The removal of mesial temporal structures, namely amygdalohippocampectomy, is the most efficient surgical procedure for the treatment of epilepsy. However, disconnection of the epileptogenic zones, as in temporal lobotomy or, for different purposes, hemispherotomy, have shown equivalent results with less morbidity. Thus, authors of the present study began performing selective amygdalohippocampotomy in cases of refractory mesial temporal lobe epilepsy (TLE) to treat mesial temporal lobe sclerosis (MTLS).

Method. The authors conducted a retrospective analysis of all cases of amygdalohippocampotomy collected in a database between November 2007 and March 2011.

Results. Since 2007, 21 patients (14 males and 7 females), ages 20–58 years (mean 41 years), all with TLE due to MTLS, were treated with selective ablation of the lateral amygdala plus perihippocampal disconnection (anterior one-half to two-thirds in dominant hemisphere), the left side in 11 cases and the right in 10. In 20 patients the followup was 2 or more years (range 24–44 months, average 32 months). Clinical outcome for epilepsy 2 years after surgery (20 patients) was good/very good in 19 patients (95%) with an Engel Class I (15 patients [75%]) or II outcome (4 patients [20%]) and bad in 1 patient (5%) with an Engel Class IV outcome (extratemporal focus and later reoperation). Surgical morbidity included hemiparesis (capsular hypertensive hemorrhage 24 hours after surgery, 1 patient), verbal memory worsening (2 patients), and quadrantanopia (permanent in 2 patients, transient in 1). Late psychiatric depression developed in 3 cases. Operative time was reduced by about 30 minutes (15%) on average with this technique.

Conclusions. Amygdalohippocampotomy is as effective as amygdalohippocampectomy to treat MTLS and is a potentially safer, time-saving procedure.

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A Comparison of Language Mapping by Preoperative Navigated Transcranial Magnetic Stimulation and Direct Cortical Stimulation During Awake Surgery

A_Comparison_of_Language_Mapping_by_Preoperative

Neurosurgery 72:808–819, 2013

Navigated transcranial magnetic stimulation (nTMS) is increasingly used in presurgical brain mapping. Preoperative nTMS results correlate well with direct cortical stimulation (DCS) data in the identification of the primary motor cortex. Repetitive nTMS can also be used for mapping of speech-sensitive cortical areas.

OBJECTIVE: The current cohort study compares the safety and effectiveness of preoperative nTMS with DCS mapping during awake surgery for the identification of language areas in patients with left-sided cerebral lesions.

METHODS: Twenty patients with tumors in or close to left-sided language eloquent regions were examined by repetitive nTMS before surgery. During awake surgery, language-eloquent cortex was identified by DCS. nTMS results were compared for accuracy and reliability with regard to DCS by projecting both results into the cortical parcellation system.

RESULTS: Presurgical nTMS maps showed an overall sensitivity of 90.2%, specificity of 23.8%, positive predictive value of 35.6%, and negative predictive value of 83.9% compared with DCS. For the anatomic Broca’s area, the corresponding values were a sensitivity of 100%, specificity of 13.0%, positive predictive value of 56.5%, and negative predictive value of 100%, respectively.

CONCLUSION: Good overall correlation between repetitive nTMS and DCS was observed, particularly with regard to negatively mapped regions. Noninvasive inhibition mapping with nTMS is evolving as a valuable tool for preoperative mapping of language areas. Yet its low specificity in posterior language areas in the current study necessitates further research to refine the methodology.

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Visual outcomes for surgical treatment of large and giant carotid ophthalmic segment aneurysms

Vision after aneurysm clipping with suction decompression

J Neurosurg 118:937–946, 2013

The authors report their results in a series of large or giant carotid ophthalmic segment aneurysms clipped using retrograde suction decompression.

Methods. A retrospective review of clinical data and treatment summaries was performed for 18 patients with large or giant carotid artery ophthalmic segment aneurysms managed operatively via retrograde suction decompression. Visual outcomes, Glasgow Outcome Scale (GOS) scores, and operative complications were determined. Postoperative angiography was assessed.

Results. During a 17-year period, 18 patients underwent surgery performed using retrograde suction decompression. The mean aneurysm size was 26 mm. Three patients presented with subarachnoid hemorrhage. Fourteen of 18 patients presented with visual symptoms. Eleven (79%) of these 14 patients experienced visual improvement and the remaining 3 (21%) experienced worsened vision after surgery. Of 3 patients without visual symptoms and a complete visual examination before and after surgery, 1 had visual worsening postoperatively. One aneurysm required trapping and bypass, and all others could be clipped. Postoperative angiography demonstrated complete occlusion in 9 of 17 clipped aneurysms and neck remnants in the other 8 clipped aneurysms. One (5.5%) of 18 patients experienced a stroke. Eighteen patients had a GOS score of 5 (good outcome), and 1 patient had a GOS score of 4 (moderately disabled). There were no deaths. There was no morbidity related to the second incision or decompression procedure. Prolonged improvement did occur, and even in some cases of visual worsening in 1 eye, the overall vision did improve enough to allow driving.

Conclusions. Retrograde suction decompression greatly facilitates surgical clipping for large and giant aneurysms of the ophthalmic segment. Visual preservation and improvement occur in the majority of these cases and is an important outcome measure. Developing endovascular technology must show equivalence or superiority to surgery for this specific outcome.

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C2 root nerve sheath tumors management

C2 tumor

Acta Neurochir (2013) 155:779–784

Upper cervical nerve sheath tumors (NST) arising mainly from C2 root and to lesser extent from C1 root are not uncommon, they constitute approximately 5-12% of spinal nerve sheath tumors and 18-30% of all cervical nerve sheath tumors, unique in presentation and their relationship to neighbouring structures owing to the discrete anatomy at the upper cervical-craniovertebral region, and have a tendency for growth reaching large-sized tumors before manifesting clinically due to the capacious spinal canal at this region; accordingly the surgical approaches to such tumors are modified.

The aim of this paper is to discuss the surgical strategies for upper cervical nerve sheath tumors.

Methods Eleven patients (8 male and 3 females), age range 28 – 63 years, with C2 root nerve sheath tumors were operated upon based on their anatomical relations to the spinal cord. The magnetic resonance imaging findings were utilized to determine the surgical approach. The tumors had extra and intradural components in 10 patients, while in one the tumor was purely intradural. The operative approaches included varied from extreme lateral transcondylar approach( n =1) to laminectomy, whether complete( n =3) or hemilaminectomy( n =7), with partial facetectomy( n =7), and with suboccipital craniectomy( n =2).

Results The clinical picture ranged from spasticity ( n =8, 72,72 %), tingling and numbness below neck ( n =6, 54,54 %), weakness ( n =6, 54,54 %), posterior column involvement ( n =4, 26,36 %), and neck pain ( n =4, 36,36 %). The duration of symptoms ranged from 1 to 54 months, total excision was performed in 7 patients; while in 3 patients an extraspinal component, and in 1 patient a small intradural component, were left in situ. Eight patients showed improvement of myelopathy; 2 patients maintained their grades. One poor-grade patient was deteriorated.

Conclusion The surgical approaches for the C2 root nerve sheath tumors should be tailored according to the relationship to the spinal cord, determined by magnetic resonance imaging.

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Minimally invasive treatment of intracerebral hemorrhage with magnetic resonance–guided focused ultrasound

Sonothrombolysis in ICH

J Neurosurg 118:1035–1045, 2013

Intracerebral hemorrhage (ICH) is a major cause of death and disability throughout the world. Surgical techniques are limited by their invasive nature and the associated disability caused during clot removal. Preliminary data have shown promise for the feasibility of transcranial MR-guided focused ultrasound (MRgFUS) sonothrombolysis in liquefying the clotted blood in ICH and thereby facilitating minimally invasive evacuation of the clot via a twist-drill craniostomy and aspiration tube.

Methods and Results. In an in vitro model, the following optimum transcranial sonothrombolysis parameters were determined: transducer center frequency 230 kHz, power 3950 W, pulse repetition rate 1 kHz, duty cycle 10%, and sonication duration 30 seconds. Safety studies were performed in swine (n = 20). In a swine model of ICH, MRgFUS sonothrombolysis of 4 ml ICH was performed. Magnetic resonance imaging and histological examination demonstrated complete lysis of the ICH without additional brain injury, blood-brain barrier breakdown, or thermal necrosis due to sonothrombolysis. A novel cadaveric model of ICH was developed with 40-ml clots implanted into fresh cadaveric brains (n = 10). Intracerebral hemorrhages were successfully liquefied (> 95%) with transcranial MRgFUS in a highly accurate fashion, permitting minimally invasive aspiration of the lysate under MRI guidance.

Conclusions. The feasibility of transcranial MRgFUS sonothrombolysis was demonstrated in in vitro and cadaveric models of ICH. Initial in vivo safety data in a swine model of ICH suggest the process to be safe. Minimally invasive treatment of ICH with MRgFUS warrants evaluation in the setting of a clinical trial.

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Transventricular Endoscopic Fenestration of Intrasellar Arachnoid Cyst

Transventricular

Neurosurgery 72:520–528, 2013

To manage arachnoid cysts, incorporation with the normal circulation is the single most important determinant of success. Although the postoperative cerebrospinal fluid leakage rate is 3.9% for all cases of transsphenoidal surgery, it is 21.4% for intrasellar arachnoid cysts.

OBJECTIVE: To present a safe, relatively easy, and effective treatment option for very rare intrasellar arachnoid cysts.

METHODS: We performed a prospective study of intrasellar cystic lesions without a solid portion. Endoscopic exploration and fenestration were performed for all lesions under neuronavigational guidance. We analyzed presenting symptoms, endocrinological status, and magnetic resonance images.

RESULTS: There were 2 male and 4 female patients with a mean age of 45 years (range, 27-67 years). All patients presented with the visual disturbance of bitemporal hemianopsia. Four patients had endocrinological symptoms including galactorrhea, dysmenorrhea, and diabetes insipidus. Endoscopic fenestration of the cyst was successfully performed in all patients. All patients were confirmed to have a pure cystic lesion, namely an arachnoid cyst. The follow-up period was 10 months on average (range, 6-12 months). Visual disturbance improved in 5 patients. Endocrinological problems persisted in all patients for 3 months and then normalized, with the exception of the patient with diabetes insipidus. There was no evidence of recurrence in any of the 6 patients in the 12-month postoperative imaging studies (median follow-up of 10 months). Two patients showed syndrome of inappropriate antidiuretic hormone at 2 and 4 weeks after the operation, but antidiuretic hormones recovered to normal levels after this time point.

CONCLUSION: Endoscopic fenestration of an intrasellar arachnoid cyst is a safe and simple procedure without serious complications.

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Microvascular decompression for hemifacial spasm: long-term outcome and prognostic factors, with emphasis on delayed cure

PE-Hemifacial

Neurosurg Rev (2013) 36:297–302

The postoperative course of microvascular decompression (MVD) for hemifacial spasm (HFS) is variable, and the optimal time for assessing the results is unclear.

From April 1997 to October 2007, MVD for HFS was performed in 801 patients. Patients were divided into two groups (cured or failed) according to subjective patient assessments over a 3-year period. We analyzed patient characteristics and surgical findings to determine prognostic factors. Medical records were analyzed retrospectively over the 3-year follow-up period.

Of the 801 patients who underwent surgery, 743 (92.8 %) appeared to be cured, 70 (8.7 %) had residual or recurrent spasms more than 1 year after surgery, 11 (1.3 %) had gradual improvement over 3 years, and 1 (0.1 %) had delayed improvement more than 3 years after surgery. Fifty-eight patients (7.2 %) had residual or recurrent spasms more than 3 years after surgery, of which 19 (2.4 %) had recurrence after initial relief. The mean time to spasm recurrence was 18.9 months. Intraoperative resolution of the lateral spread response (LSR) after decompression (p=0.048) and severe indentation (p=0.038) were significant predictors of good long-term outcome after MVD for HFS.

In our series, 70 patients (8.7 %) had residual or recurrent spasms more than 1 year after surgery, of which 12 (17.1 %) improved gradually after 1 year. If the surgeon can confirm intraoperative resolution of the LSR and severe indentation, reoperation can be delayed until 3 years after MVD.

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Navigated transcranial magnetic stimulation for mapping the motor cortex in patients with rolandic brain tumors

Navigated transcranial

Neurosurg Focus 34 (4):E3, 2013

Navigated transcranial magnetic stimulation (nTMS) is a novel technology in the field of neurosurgery for noninvasive delineation of cortical functional topography. This study addresses the spatial accuracy and clinical usefulness of nTMS in brain tumor surgery in or near the motor cortex based on a systematic review of observational studies.

Methods. A systematic search retrieved 11 reports published up to October 2012 in which adult patients were examined with nTMS prior to surgery. Quality criteria consisted of documentation of the influence of nTMS brain mapping on clinical decision making in a standardized prospective manner and/or performance of intraoperative direct electrical stimulation (DES) and comparison with nTMS results. Cross-observational assessment of nTMS accuracy was established by calculating a weighted mean distance between nTMS and DES.

Results. All studies reviewed in this article concluded that nTMS correlated well with the “gold standard” of DES. The mean distance between motor cortex identified on nTMS and DES by using the mean distance in 81 patients described in 6 quantitatively evaluated studies was 6.18 mm. The nTMS results changed the surgical strategy based on anatomical imaging alone in 25.3% of all patients, based on the data obtained in 87 patients in 2 studies.

Conclusions. The nTMS technique spatially correlates well with the gold standard of DES. Its functional information benefits surgical decision making and changes the treatment strategy in one-fourth of cases.

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Minimal access to deep intracranial lesions using a serial dilatation technique

Minimal access to deep intracranial lesions

Neurosurg Rev (2013) 36:321–330

Surgical access to deep intracranial lesions causing the least amount of iatrogenic trauma to the surrounding brain tissue remains a challenging task. In this article, we evaluate the use of a set of sequential tubes that dilate and provide retraction of the overlying brain tissue acting as a surgical corridor for deep-seated brain lesions resection. In addition, we conducted a comprehensive review of the literature of previously described techniques using variable brain tubular retractor systems. We discuss the adaptation of a system designed for spinal use to intracranial pathologies and evaluate the outcomes for the patients involved in the study. Moreover, the advantages and limitations of the described technique were presented.

Between August 2005 and 2011, a total of 30 patients with deep brain lesions were operated on using an incremental increase of tubing size for brain retraction guided by a frameless navigation device. Of these, seven cases were intraventricular, and 23 were intraparenchymal. Gross total resection was achieved in 70 % of cases, and the remaining had planned subtotal resections due to involvement of an eloquent area.

In conclusion, the technique of serial dilatation of the brain tissue can be used in conjunction with a microscope or endoscope to provide satisfactory access to deep intracranial pathologies. It appears to minimize the associated retraction injury to the surrounding tissue by gradually dilating the white fiber tracts. This operative approach may be considered as an effective and safe alternative for brain tumor resections in selected cases, especially deep-seated lesions.

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Flat-Panel Fluoroscopy O-arm–Guided Percutaneous Radiofrequency Cordotomy: A New Technique for the Treatment of Unilateral Cancer Pain

O-arm cordotomy

Neurosurgery 72[ONS Suppl 1]:ons27–ons34, 2013

Percutaneous radiofrequency cordotomy (PRFC) involves controlled ablation of the anterolateral quadrant of the spinal cord, thereby relieving pain. Evolving from a morbid open surgery, the procedure has been modernized through the application of physiological target confirmation, well-regulated thermal ablation, and improved intraoperative imaging.

OBJECTIVE: To evaluate the utility in PRFC of a new high-resolution, portable flatpanel fluoroscopic imaging technology, the O-arm Imaging System. The O-arm allows traditional 2-dimensional fluoroscopy in addition to axial and 3-dimensional reconstructed computed tomography imaging.

METHODS: PRFC was performed using the O-arm Imaging System in 6 patients with unilateral cancer pain.

RESULTS: Patients experienced 90% to 100% initial pain relief, with 50% to 100% sustained pain relief at the time of death at 2 to 12 months. There were no complications.

CONCLUSION: Portable flat-panel fluoroscopy allows high-resolution, readily updated computed tomography and fluoroscopic image guidance during PRFC. Use of this new technology may assist neurosurgeons in providing an important analgesic intervention at centers possessing the imaging technology.

KEY WORDS:

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Pelvic Schwannoma: Robotic Laparoscopic Resection

Pelvic Schwannoma- Robotic Laparoscopic Resection

Neurosurgery 72[ONS Suppl 1]:ons2–ons5, 2013

Schwannoma is a rare benign tumor of peripheral nerves arising from Schwann cells of the ubiquitous nerve sheath.

OBJECTIVE: To describe the operative steps and technical aspects of robotic laparoscopic resection of pelvic schwannoma.

METHODS: We describe 2 patients with pelvic schwannoma: a 34-year-old woman with schwannoma of the right lumbosacral trunk and a 58-year-old woman with schwannoma of a left S1 nerve. Pain was the main symptom in both patients. The diagnosis was confirmed by magnetic resonance imaging and nerve biopsies. Both patients were operated on by robotic laparoscopy.

RESULTS: Lesions were totally enucleated after incising the epineurium. After dissection of the schwannoma, the vascular pedicle and nerve fascicles involved were identified, coagulated, and then sectioned. The remaining fascicles of the nerve were preserved. The postoperative course was uneventful in both patients. With follow-up of 9 and 13 months, both patients obtained complete pain relief with no neurological sequelae. CONCLUSION: Robotic laparoscopic resection of pelvic nerve tumors such as schwannomas is technically feasible.

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Extracranial-Intracranial Bypass and Vessel Occlusion for the Treatment of Unclippable Giant Middle Cerebral Artery Aneurysms

Extracranial_Intracranial_Bypass_and_Vessel

Neurosurgery 72:428–436, 2013

Giant middle cerebral artery (MCA) aneurysms pose management challenges.

OBJECTIVE: To review the outcomes of patients with giant MCA aneurysms not amenable to clipping or vessel reconstruction treated with extracranial-intracranial (EC-IC) bypass and vessel sacrifice.

METHODS: We retrospectively reviewed a database of aneurysms treated at our institution between 1983 and 2011.

RESULTS: Sixteen patients (11 males, 5 females) were identified. There were 10 saccular, 4 fusiform, and 2 serpentine aneurysms. The aneurysms predominantly involved the M1 segment in 5 cases, M2 in 9 cases, and both M1 and M2 in 2 cases. The EC-IC bypasses performed included 13 superficial temporal artery-MCA, 1 saphenous vein graft-MCA, and 2 radial artery grafts-MCA. The postoperative bypass patency rate was 93.8% (15/16). There were 3 cerebrovascular accidents (18.8%), but no perioperative deaths (0% mortality). The mean follow-up was 58.4 months (range, 1-265; median, 23.5 months). In 75% (12/16) of cases the aneurysms were occluded successfully. A small residual was noted in 3 cases with the use of this treatment strategy, and they were re-treated. In a fourth case treated with partial distal occlusion, reduced flow through the aneurysm was noted postoperatively, but the patient did not undergo further treatment. The mean modified Rankin scale and mean Glasgow Outcome Scale scores at last follow-up were 1.6 (range, 1-4; median, 1) and 4.8 (range, 3-5; median, 5), respectively.

CONCLUSION: Giant MCA aneurysms are challenging lesions. EC-IC bypass with parent vessel occlusion can provide a durable form of treatment with acceptable rates of morbidity and mortality.

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Intraoperative visualisation of language fascicles by diffusion tensor imaging-based tractography in glioma surgery

Intraop visualization language fascicles-3

Acta Neurochir (2013) 155:437–448

For gliomas, the goal of surgery is to maximise the extent of resection (EOR) while minimising the postoperative morbidity. The purpose of this study was to evaluate the benefits of a protocol developed for the surgical management of gliomas located in language areas, where tractography-integrated navigation was used in conjunction with direct electrical stimulations (DES).

Methods and materials The authors included ten patients suffering of gliomas located in language areas. The preoperative planning for multimodal navigation was done by integrating anatomical magnetic resonance images and subcortical pathway volumes generated by diffusion tensor imaging. Six white matter fascicles implicated in language functions were reconstructed in each patient, including fibres for phonological processing (i.e. the arcuate fasciculus), fibres for lexical-semantic processing (i.e. the inferior frontooccipital fasciculus, inferior longitudinal fasciculus and uncinate fasciculus), and two premotor fasciculi involved in the preparation of speech movements (the subcallosal medialis fasciculus and cortical fibres originating from the medial and lateral premotor areas). During surgery, language fascicles were identified by direct visualisation on tractography-integrated navigation images and by observing transient language inhibition after subcortical DES. Language deficits were evaluated preoperatively and postoperatively, and compared with the EOR.

Results Tractography was successfully performed in all patients, preoperatively demonstrating the relationships between the tumours to resect and the language fascicles to preserve from injury. With the use of the tractographyintegrated navigation system and intraoperative DES, language functions were preserved in all patients. The mean volumetric resection was 93.0±10.4 % of the preoperative tumour volume, with a gross total resection in 60 % of patients.

Conclusion The intraoperative combination of tractography and DES contributed to maximum safe resection of gliomas located in language areas.

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Indocyanine green videoangiography (ICGV)-guided surgery of parasagittal meningiomas occluding the superior sagittal sinus (SSS)

ICG meningioma

Acta Neurochir (2013) 155:415–420

Maximal safe resection is the goal of correct surgical treatment of parasagittal meningiomas, and it is intimately related to the venous anatomy both near and directly involved by the tumor. Indocyanine green videoangiography (ICGV) has already been advocated as an intra-operative resourceful technique in brain tumor surgery for the identification of vessels. The aim of this study was to investigate the role of ICGV in surgery of parasagittal meningiomas occluding the superior sagittal sinus (SSS).

Method In this study, we prospectively analyzed clinical, radiological and intra-operative findings of patients affected by parasagittal meningioma occluding the SSS, who underwent ICGVassisted-surgery. Radiological diagnosis of complete SSS occlusion was pre-operatively established in all cases. ICGV was performed before dural opening, before and during tumor resection, at the end of the procedure.

Results Five patients were included in our study. In all cases, ICGV guided dural opening, tumor resection, and venous management. The venous collateral pathway was easily identified and preserved in all cases. Radical resection was achieved in four cases. Surgery was uneventful in all cases.

Conclusions Despite the small number of patients, our study shows that ICG videoangiography could play a crucial role in guiding surgery of parasagittal meningioma occluding the SSS. Further studies are needed to define the role of this technique on functional and oncological outcome of these patients.

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Surgical Treatment of Ruptured Anterior Circulation Aneurysms: Comparison of Pterional and Supraorbital Keyhole Approaches

Surgical_Treatment_of_Ruptured_Anterior

Neurosurgery 72:437–442, 2013

Recent advancements in microsurgical techniques and instrumentation have allowed the development of the keyhole approach in aneurysm surgery.

OBJECTIVE: To compare the safety, efficacy, and 1-year clinical outcome of supraorbital keyhole and standard pterional approaches for ruptured anterior circulation aneurysms.

METHODS: A total of 87 patients underwent surgical clipping, 40 through the pterional and 47 through the supraorbital keyhole approach. Baseline demographics, operative time, procedural complications, and 1-year patient outcome were retrospectively compared.

RESULTS: The 2 groups were comparable with respect to baseline characteristics, with the exception of a higher proportion of small aneurysms (,7 mm) in the supraorbital group (70.2% vs 37.5%, P = .002). Total operative time was significantly shorter in the supraorbital group (205 minutes, P , .001) compared with the pterional group (256 minutes). The rate of procedural complications was lower in patients treated through the pterional (17.5%) vs the supraorbital approach (23.4%, P = .4). Intraoperative aneurysm ruptures occurred more frequently in the supraorbital group (10.6% vs 2.5%). No patient experienced early or late rebleeding in either group. One year after treatment, 75% (30/40) of patients achieved a favorable outcome (Glasgow Outcome Scale IV or V) in the pterional group vs 76.6% (36/47) in the supraorbital group (P = .8).

CONCLUSION: The rate of procedural complications may be higher with the supraorbital keyhole approach, but overall patient outcomes appear to be comparable. The pterional approach is a simple, reliable, and efficient procedure. The keyhole approach may be an acceptable alternative for neurosurgeons who have gained sufficient experience with the technique, especially for small noncomplex aneurysms.

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Axial Spondylectomy and Circumferential Reconstruction via a Posterior Approach

Axial spondylectomy

Neurosurgery 72:300–309, 2013

Spinal metastases of the second cervical vertebra are a subset of tumors that are particularly difficult to address surgically. Previously described techniques require highly morbid circumferential dissection posterior to the pharynx for resection and reconstruction.

OBJECTIVE: To perform a biomechanical analysis of instrumented reconstruction configurations used after axial spondylectomy and to demonstrate safe use of a novel construct in a patient case report.

METHODS: Several different published and novel reconstruction configurations were inserted into 7 occipitocervical spines that underwent axial spondylectomy. A biomechanical analysis of the stiffness of the constructs in flexion and extension, lateral bending, and rotation was performed. A patient then underwent a posterior-only approach for axial spondylectomy and circumferential reconstruction.

RESULTS: Biomechanical analysis of different constructs demonstrated that anterior column reconstruction with bilateral cages spanning the C1 lateral mass to the C3 facet in combination with occipitocervical instrumentation was superior in flexion-extension and equivalent in lateral bending and rotation to currently used constructs. The patient in whom this construct was placed via a posterior-only approach for axial spondylectomy and instrumentation remained at neurological baseline and demonstrated no recurrence of local disease or failure of instrumentation to date.

CONCLUSION: When C1 lateral mass to C3 facet bilateral cage plus occipitocervical instrumentation is compared with existing anterior and posterior constructs, this novel reconstruction is biomechanically equivalent if not superior in performance. In a patient, the posterior-only approach for C2 spondylectomy with the novel reconstruction was safe and durable and avoided the morbidity of the anterior approach.

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The Y-shaped double-barrel bypass in the treatment of large and giant anterior communicating artery aneurysms

Y-shaped bypass

J Neurosurg 118:444–450, 2013

Large and giant anterior communicating artery (ACoA) aneurysms usually show partial thrombosis and incorporate both the A1 and A2 segments and crucial perforating vessels. Therefore, direct clip placement or endovascular strategies often fail, leaving cerebral bypass surgery as a relevant therapeutic option.

The authors present 3 cases in which a giant or large ACoA aneurysm was successfully occluded using a new technique that applies a double-barrel radial artery bypass. A radial artery graft is modified into a Y-shaped double-barrel conduit. After both pterional and parasagittal craniotomies are carried out, the graft is tunneled between both sites and anastomosed in an end-to-side fashion proximally to either a superficial temporal artery (STA) or M2 branch and distally to bilateral A3 branches. Aneurysm occlusion is then conducted through the pterional or parasagittal craniotomy.

In one case, a 42-year-old patient in whom an endovascular approach had failed, the authors performed an STA-A3-A3 bypass and proximal aneurysm occlusion. In two others, a 49-year-old man in whom coiling had failed and a 56-year-old man in whom a giant ACoA aneurysm was partially thrombosed, the authors performed an M2-A3-A3 double-barrel bypass followed by either proximal or distal aneurysm occlusion. Complete aneurysm occlusion with excellent bypass perfusion was documented in the first two cases. In the third case, the authors observed good bypass perfusion with persistent antegrade aneurysm filling, and thus endovascular coil embolization was added to completely occlude the aneurysm.

The Y-shaped double-barrel bypass using a radial artery graft allows for safe and effective occlusion of large and giant ACoA aneurysms that cannot be treated by direct clip application.

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Combined “Hybrid” Open and Minimally Invasive Surgical Correction of Adult Thoracolumbar Scoliosis: A Retrospective Cohort Study

00006123-201302000-00011

Neurosurgery 72:151–159, 2013

Surgery for scoliosis requires extensive exposure, resulting in significant tissue injury and longer recovery times. To minimize morbidity in scoliosis surgery, several studies have shown successful application of a combination of minimally invasive techniques; however, the extent of scoliosis treated has been modest.

OBJECTIVE: To achieve some of the benefits of minimally invasive surgery and yet treat curves of greater degree, we have used a combined approach, incorporating both open and minimally invasive techniques.

METHODS: We analyzed a prospectively acquired database in addition to reviewing electronic records of patients undergoing hybrid surgery for thoracolumbar scoliosis. Nine patients were identified. The minimally invasive portion involved the lumbar region in all cases. Pain was assessed by the visual analog scale and disability was measured by the Oswestry Disability Index.

RESULTS: Mean preoperative scoliosis was 47.8 degrees, which was corrected to a mean 15.2 degrees. An average of 7.8 spinal levels was treated. Estimated blood loss averaged 1094.4 mL, and length of hospital stay averaged 7.2 days. Acute complications occurred in 2 patients. Longer term complications occurred in 2 patients, consisting of adjacent segment disease. The mean improvement in the visual analog scale score was 3.7 and the mean improvement on the Oswestry Disability Index was 30.5. Average follow-up was 29.2 months.

CONCLUSION: The hybrid approach for the treatment of scoliosis results in acceptable radiographic and clinical outcomes. Complications did not appear increased compared with those expected with scoliosis surgery. Although decreased adjacent tissue injury was achieved with the minimally invasive component of the procedure, a larger comparative study is required to determine magnitude of this benefit.

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Technical nuances for surgery of insular gliomas: lessons learned

0340006f9

Neurosurgical Focus Feb 2013 / Vol. 34 / No. 2 / Page E6

Insular gliomas were traditionally considered a nonsurgical entity due to the high morbidity associated with resection. For the past 20 years, advances in microsurgical and brain mapping techniques have allowed neurosurgeons to resect insular gliomas with acceptable morbidity rates. Maximizing the extent of resection is nowadays the goal of surgery since this has proven to be an independent factor contributing to longer survival. Despite much progress, insular tumors remain a challenge for the neurosurgeon due to the complex anatomy of the region and technical expertise required to minimize morbidity during surgery.

Herein, the authors describe the current surgical nuances, based on their experience and a literature review, that will allow the surgeon to achieve a thorough resection while ensuring patient safety. The key factors for successful surgery in the insular region include detailed knowledge of the surgical anatomy, mastery of the nuances of cortical and subcortical mapping methods, and meticulous microsurgical technique.

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