Author: cba

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Avoidance and management of perioperative complications of endoscopic third ventriculostomy

Usefulness of Intraoperative Magnetic Resonance Ventriculography During Endoscopic Third Ventriculostomy

J Neurosurg 123:1414–1419, 2015

Although endoscopic third ventriculostomy (ETV) is a minimally invasive procedure, serious perioperative complications may occur due to the unique surgical maneuvers involved. In this paper the authors report the complications of elective and emergency ETV and their surgical management in 412 patients from July 2006 to October 2012 at Dhaka Medical College Hospital (a government hospital) and other private hospitals in Dhaka, Bangladesh. The authors attempted some previously undescribed simple maneuvers that may help to overcome the difficulties of managing complications.

METHODS The complication rate was determined by recording intraoperative changes in pulse and blood pressure, bleeding episodes, serum electrolyte abnormalities, CSF leakage, and neurological deterioration in the immediate postoperative period.

RESULTS Intraoperative complications included hemodynamic alterations in the form of tachycardia, bradycardia, and hypertension. Bleeding was categorized as major in 2 cases and minor in 68 cases. Delayed recovery from anesthesia occurred in 14 cases, CSF leakage from the wound in 11 cases, and electrolyte imbalance in 5 cases. Postoperatively, 2 patients suffered convulsions and 1 had evidence of third cranial nerve injury. Three patients died as a result of complications.

CONCLUSIONS Complications during endoscopy can lead to serious consequences that may sometimes be very difficult to manage. The authors have identified and managed a large number of complications in this series, although the rate of complications is consistent with that in other reported series. These complications should be kept in mind perioperatively by both surgeons and anesthesiologists, as prompt detection and action can help minimize the risks associated with neuroendoscopic procedures.

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Electrophysiological validation of STN-SNr boundary depicted by susceptibility-weighted MRI

Electrophysiological validation of STN-SNr boundary depicted by susceptibility-weighted MRI

Acta Neurochir (2015) 157:2129–2134

Direct targeting of subthalamic nucleus (STN) without secondary electrophysiological verification during deep brain stimulation (DBS) is replacing atlas-based indirect targeting techniques. Recent groups have reported increased contrast and better delineation of STN and substantia nigra (SNr) in susceptibility-weighted imaging protocols (SWI). We aim to validate the STN-SNr boundary seen in MRISWI by correlating with intraoperative microelectrode recordings (MER) as a part of developing a multi-contrast DBSMRI planning protocol.

Methods Prospective service evaluation involving electrophysiological verification by correlation of MER trajectory and STN-SNr boundary seen in SWI in seven consecutive patients undergoing DBS surgery were analyzed. The angle of inclination of the STN-SNr boundary and DBS trajectory in the coronal plane were calculated. Considering 4-mm dispersion of a coronal 3 MER array, we predicted, measured, and correlated the depths at which each electrode engaged the boundary.

Results All central microelectrodes identified the STN-SNr boundary within 1 mm of the predicted depth with 100 % accuracy. Ninety percent of the lateral MER identified the STN-SNr boundary as predicted from SWI and angle of the encounter of the MER front.

Conclusions The study demonstrates that STN morphology can be depicted using SWI MRI and coincides reliably with the electrophysiological MER boundary. Thus, this imaging modality can be used to refine STN direct targeting protocols in DBS surgery for PD.

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Resolution of Oculomotor Nerve Palsy Secondary to Posterior Communicating Artery Aneurysms- Comparison of Clipping and Coiling

Advanced Technical Skills Are Required for Microsurgical Clipping of Posterior Communicating Artery Aneurysms in the Endovascular Era-0

Neurosurgery 77:931–939, 2015

Previous studies have attempted to determine the best treatment for oculomotor nerve palsy (ONP) secondary to posterior communicating artery (PCoA) aneurysms, but have been limited by small sample sizes and limited treatment.

OBJECTIVE: To analyze the treatment of ONP secondary to PCoA with both coiling and clipping in ruptured and unruptured aneurysms.

METHODS: Data from 2 large academic centers was retrospectively collected over 22 years, yielding a total of 93 patients with ONP secondary to PCoA aneurysms. These patients were combined with 321 patients from the literature review for large data analyses. Onset symptoms, recovery, and time to resolution were evaluated with respect to treatment and aneurysm rupture status.

RESULTS: For all patients presenting with ONP (n = 414) 56.6% of those treated with microsurgical clipping made a full recovery vs 41.5% of those treated with endovascular coil embolization (P = .02). Of patients with a complete ONP (n = 229), full recovery occurred in 47.3% of those treated with clipping but in only 20% of those undergoing coiling (P = .01). For patients presenting with ruptured aneurysms (n = 130), full recovery occurred in 70.9% compared with 49.3% coiled patients (P = .01). Additionally, although patients with full ONP recovery had a median time to treatment of 4 days, those without full ONP recovery had a median time to treatment of 7 days (P = .01).

CONCLUSION: Patients with ONP secondary to PCoA aneurysms treated with clipping showed higher rates of full ONP resolution than patients treated with coil embolization. Larger prospective studies are needed to determine the true potential of recovery associated with each treatment.

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The role of sacral slope in lumbosacral fusion: a biomechanical study

sacral slope in LS fusion

J Neurosurg Spine 23:754–762, 2015

Abnormal sacral slope (SS) has shown to increase progression of spondylolisthesis, yet there exists a paucity in biomechanical studies investigating its role in the correction of adult spinal deformity, its influence on lumbosacral shear, and its impact on the instrumentation selection process. This in vitro study investigates the effect of SS on 3 anterior lumbar interbody fusion constructs in a biomechanics laboratory.

Methods Nine healthy, fresh-frozen, intact human lumbosacral vertebral segments were tested by applying a 550- N axial load to specimens with an initial SS of 20° on an MTS Bionix test system. Testing was repeated as SS was increased to 50°, in 10° increments, through an angulated testing fixture. Specimens were instrumented using a standalone integrated spacer with self-contained screws (SA), an interbody spacer with posterior pedicle screws (PPS), and an interbody spacer with anterior tension band plate (ATB) in a randomized order. Stiffness was calculated from the linear portion of the load-deformation curve. Ultimate strength was also recorded on the final construct of all specimens (n = 3 per construct) with SS of 40°.

Results Axial stiffness (N/mm) of the L5–S1 motion segment was measured at various angles of SS: for SA 292.9 ± 142.8 (20°), 277.2 ± 113.7 (30°), 237.0 ± 108.7 (40°), 170.3 ± 74.1 (50°); for PPS 371.2 ± 237.5 (20°), 319.8 ± 167.2 (30°), 280.4 ± 151.7 (40°), 233.0 ± 117.6 (50°); and for ATB 323.9 ± 210.4 (20°), 307.8 ± 125.4 (30°), 249.4 ± 126.7 (40°), 217.7 ± 99.4 (50°). Axial compression across the disc space decreased with increasing SS, indicating that SS beyond 40° threshold shifted L5–S1 motion into pure shear, instead of compression-shear, defining a threshold. Trends in ultimate load and displacement differed from linear stiffness with SA > PPS > ATB.

Conclusions At larger SSs, bilateral pedicle screw constructs with spacers were the most stable; however, none of the constructs were significantly stiffer than intact segments. For load to failure, the integrated spacer performed the best; this may be due to angulations of integrated plate screws. Increasing SS significantly reduced stiffness, which indicates that surgeons need to consider using more aggressive fixation techniques.

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Combined use of diffusion tensor tractography and multifused contrast-enhanced FIESTA for predicting facial and cochlear nerve positions in relation to vestibular schwannoma

Combined use of diffusion tensor tractography and multifused contrast-enhanced FIESTA for predicting facial and cochlear nerve positions in relation to vestibular schwannoma

J Neurosurg 123:1480–1488, 2015

The authors assessed whether the combined use of diffusion tensor tractography (DTT) and contrastenhanced (CE) fast imaging employing steady-state acquisition (FIESTA) could improve the accuracy of predicting the courses of the facial and cochlear nerves before surgery.

Methods The population was composed of 22 patients with vestibular schwannoma in whom both the facial and cochlear nerves could be identified during surgery. According to DTT, depicted fibers running from the internal auditory canal to the brainstem were judged to represent the facial or vestibulocochlear nerve. With regard to imaging, the authors investigated multifused CE-FIESTA scans, in which all 3D vessel models were shown simultaneously, from various angles. The low-intensity areas running along the tumor from brainstem to the internal auditory canal were judged to represent the facial or vestibulocochlear nerve.

Results For all 22 patients, the rate of fibers depicted by DTT coinciding with the facial nerve was 13.6% (3/22), and that of fibers depicted by DTT coinciding with the cochlear nerve was 63.6% (14/22). The rate of candidates for nerves predicted by multifused CE-FIESTA coinciding with the facial nerve was 59.1% (13/22), and that of candidates for nerves predicted by multifused CE-FIESTA coinciding with the cochlear nerve was 4.5% (1/22). The rate of candidates for nerves predicted by combined DTT and multifused CE-FIESTA coinciding with the facial nerve was 63.6% (14/22), and that of candidates for nerves predicted by combined DTT and multifused CE-FIESTA coinciding with the cochlear nerve was 63.6% (14/22). The rate of candidates predicted by DTT coinciding with both facial and cochlear nerves was 0.0% (0/22), that of candidates predicted by multifused CE-FIESTA coinciding with both facial and cochlear nerves was 4.5% (1/22), and that of candidates predicted by combined DTT and multifused CE-FIESTA coinciding with both the facial and cochlear nerves was 45.5% (10/22).

Conclusions By using a combination of DTT and multifused CE-FIESTA, the authors were able to increase the number of vestibular schwannoma patients for whom predicted results corresponded with the courses of both the facial and cochlear nerves, a result that has been considered difficult to achieve by use of a single modality only. Although the 3D image including these prediction results helped with comprehension of the 3D operative anatomy, the reliability of prediction remains to be established.

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Prognostic Value of the Amount of Bleeding After Aneurysmal Subarachnoid Hemorrhage: A Quantitative Volumetric Study

SAH

Neurosurgery 77:898–907, 2015

Quantitative estimation of the hemorrhage volume associated with aneurysm rupture is a new tool of assessing prognosis.

OBJECTIVE: To determine the prognostic value of the quantitative estimation of the amount of bleeding after aneurysmal subarachnoid hemorrhage, as well the relative importance of this factor related to other prognostic indicators, and to establish a possible cut-off value of volume of bleeding related to poor outcome.

METHODS: A prospective cohort of 206 patients consecutively admitted with the diagnosis of aneurysmal subarachnoid hemorrhage to Hospital 12 de Octubre were included in the study. Subarachnoid, intraventricular, intracerebral, and total bleeding volumes were calculated using analytic software. For assessing factors related to prognosis, univariate and multivariate analysis (logistic regression) were performed. The relative importance of factors in determining prognosis was established by calculating their proportion of explained variation. Maximum Youden index was calculated to determine the optimal cut point for subarachnoid and total bleeding volume.

RESULTS: Variables independently related to prognosis were clinical grade at admission, age, and the different bleeding volumes. The proportion of variance explained is higher for subarachnoid bleeding. The optimal cut point related to poor prognosis is a volume of 20 mL both for subarachnoid and total bleeding.

CONCLUSION: Volumetric measurement of subarachnoid or total bleeding volume are both independent prognostic factors in patients with aneurysmal subarachnoid hemorrhage. A volume of more than 20 mL of blood in the initial noncontrast computed tomography is related to a clear increase in poor outcome risk.

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Surgically managed idiopathic intracranial hypertension in adults

Idiopathic intracranial hypertension

Acta Neurochir (2015) 157:2099–2103

Idiopathic intracranial hypertension (IIH) is a rare condition that is often managed conservatively. In patients with aggressive progression of the disease surgical options are considered. There are few data on the outcomes of these patients when surgically managed. We describe our experience of surgically managed IIH and the outcomes of these patients, in particular the surgical revision rate and interventions required for resolution of symptoms.

Methods A retrospective review of all patient files coded with benign intracranial hypertension, idiopathic intracranial hypertension or pseudotumour cerebri was undertaken. Files were searched with the date of diagnosis and the date these patients were referred for surgical intervention. The surgical interventions and complications were then documented and note was made of the number of inpatient admissions and days spent in hospital.

Results From 2000–2013, 79 patients were identified as patients with IIH that had required surgical intervention; 52 % required further surgical intervention. The average number of surgical interventions was 5.6. For patients requiring further intervention the average number of surgical interventions was 8.6. On average patients with IIH also spent 42 inpatient days in neurosurgical beds, whilst those patients who required further intervention spent 63 days on average in neurosurgical beds. The length of the average individual admission was longer for patients requiring repeated surgical interventions.

Conclusion Based on our experience, patients that require surgical management of IIH frequently require further surgical interventions to control symptoms and manage complications of CSF diversion surgery. Those that require such further intervention on average will have six further operations and spend significantly longer in hospital. Lumboperitoneal (LP) shunting is an effective first line surgical intervention for 52% of our patient cohort. This sub-group of patients therefore requires specialist neurosurgical input for this long-term and challenging pathological process.

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Surgical Outcomes for Minimally Invasive vs Open Transforaminal Lumbar Interbody Fusion

tlif-x-ray-lat

Neurosurgery 77:847–874, 2015

Minimally invasive transforaminal lumbar interbody fusion (TLIF)—or MI-TLIF—has been increasing in prevalence compared with open TLIF (O-TLIF) procedures. The use of MI-TLIF is an evolving technique with conflicting reports in the literature about outcomes.

OBJECTIVE: To investigate the impact of MI-TLIF in comparison with O-TLIF for early and late outcomes by using the Visual Analog Scale for back pain (VAS-back) and the Oswestry Disability Index (ODI). Secondary end points include blood loss, operative time, radiation exposure, length of stay, fusion rates, and complications between the 2 procedures.

METHODS: During August 2014, a systematic literature search was performed identifying 987 articles. Of these, 30 met inclusion criteria. A random-effects meta-analysis was performed by using both pooled and subset analyses based on study type.

RESULTS: Our meta-analysis demonstrated that MI-TLIF reduced blood loss (P < .001), length of stay (P < .001), and complications (P = .001) but increased radiation exposure (P < .001). No differences were found in fusion rate (P = .61) and operative time (P = .34). A decrease in late VAS-back scores was demonstrated for MI TLIF (P < .001), but no differences were found in early VAS-back, early ODI, and late ODI.

CONCLUSION: MI-TLIF is associated with reduced blood loss, decreased length of stay, decreased complication rates, and increased radiation exposure. The rates of fusion and operative time are similar between MI-TLIF and O-TLIF. Differences in long-term outcomes in MI-TLIF vs O-TLIF are inconclusive and require more research, particularly in the form of large, multi-institutional prospective randomized controlled trials.

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Deep Brain Stimulation of Heschl Gyrus

Heschl

Neurosurgery 77:940–947, 2015

Tinnitus is a source of considerable morbidity, and neuromodulation has been shown to be a potential treatment option. However, the location of the primary auditory cortex within Heschl gyrus in the temporal operculum presents challenges for targeting and electrode implantation.

OBJECTIVE: To determine whether anatomic targeting with intraoperative verification using evoked potentials can be used to implant electrodes directly into the Heschl gyrus (HG).

METHODS: Nine patients undergoing stereo-electroencephalogram evaluation for epilepsy were enrolled. HG was directly targeted on volumetric magnetic resonance imaging, and framed stereotaxy was used to implant an electrode parallel to the axis of the gyrus by using an oblique anterolateral-posteromedial trajectory. Intraoperative evoked potentials from auditory stimuli were recorded from multiple electrode contacts. Postoperatively, stimulation of each electrode was performed and participants were asked to describe the percept. Audiometric analysis was performed for 2 participants during subthreshold stimulation.

RESULTS: Sounds presented to the contralateral and ipsilateral ears produced evoked potentials in HG electrodes in all participants intraoperatively. Stimulation produced a reproducible sensation of sound in all participants with perceived volume proportional to amplitude. Four participants reported distinct sounds when different electrodes were stimulated, with more medial contacts producing tones perceived as higher in pitch. Stimulation was not associated with adverse audiometric effects. There were no complications of electrode implantation.

CONCLUSION: Direct anatomic targeting with physiological verification can be used to implant electrodes directly into primary auditory cortex. If deep brain stimulation proves effective for intractable tinnitus, this technique may be useful to assist with electrode implantation.

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In-Pipeline Stenosis: Incidence, Predictors, and Clinical Outcomes

In-Pipeline Stenosis- Incidence, Predictors, and Clinical Outcomes

Neurosurgery 77:875–879, 2015

The Pipeline Embolization Device is a widely utilized flow diverter in the treatment of intracranial aneurysms.

OBJECTIVE: To assess the incidence, clinical significance, predictors, and outcomes of in-Pipeline stenosis (IPS).

METHODS: Angiographic studies in 139 patients treated between 2011 and 2013 were independently reviewed by 2 authors for the presence of IPS. Multivariable logistic regression analysis was conducted to determine predictors of IPS.

RESULTS: A total of 21 (15.8%) patients demonstrated some degree of IPS during the follow-up period at a mean time point of 6.7 months (range, 3-24 months). The stenosis was mild (,50%) in 11 patients, moderate (50%-75%) in 5, and severe (.75%) in 6. None were symptomatic or required further intervention. Sixteen of these 22 patients (73%) had IPS detected within 6 months. IPS was noted in 7.6% (1/13) of patients with posterior circulation aneurysms vs 16.7% (21/126) of those with anterior circulation aneurysms (P = .03). The rate of IPS was 60% (3/5) in patients who did not receive aspirin vs only 14.2% (19/134) in those who received aspirin (P = .02). In multivariable analysis, no aspirin therapy (odds ratio, 10.0; 95% confidence interval, 1.4-67.7; P = .02) and internal carotid artery aneurysm location (odds ratio, 3.1; 95% confidence interval, 1.1-8.8; P = .03) were strong independent predictors of IPS.

CONCLUSION: IPS is a common, early, and mostly benign complication. Patients with internal carotid artery aneurysms are more likely to develop IPS. Aspirin plays a key role in preventing IPS. The results of this study further support the safety of flow diverters.

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Stereoelectroencephalography-guided radiofrequency thermocoagulation in the epileptogenic zone

Reducing surgical site infections following craniotomy- examination of the use of topical vancomycin

J Neurosurg 123:1600–1604, 2015

Although the use of topical vancomycin has been shown to be safe and effective for reducing postoperative infection rates in patients after spine surgery, its use in cranial wounds has not been studied systematically. The authors hypothesized that topical vancomycin, applied in powder form directly to the subgaleal space during closure, would reduce cranial wound infection rates.

Methods A cohort of 150 consecutive patients who underwent craniotomy was studied retrospectively. Seventy-five patients received 1 g of vancomycin powder applied in the subgaleal space at the time of closure. This group was compared with 75 matched-control patients who were accrued over the same time interval and did not receive vancomycin. The primary outcome measure was the presence of surgical site infection within 3 months. Secondary outcome measures included tissue pH from a subgaleal drain and vancomycin levels from the subgaleal space and serum.

Results Vancomycin was associated with significantly fewer surgical site infections (1 of 75) than was standard antibiotic prophylaxis alone (5 of 75; p < 0.05). Cultures were positive for typical skin flora species. As expected, local measured vancomycin concentrations peaked immediately after surgery (mean ± SD 499 ± 37 μg/ml) and gradually decreased over 12 hours. Vancomycin in the circulating serum remained undetectable. Subgaleal topical vancomycin was associated with a lower incidence of surgical site infections after craniotomy. The authors attribute this reduction in the infection rate to local vancomycin concentrations well above the minimum inhibitory concentration for antimicrobial efficacy.

Conclusions Topical vancomycin is safe and effective for reducing surgical site infections after craniotomy. These data support the need for a prospective randomized examination of topical vancomycin in the setting of cranial surgery.

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Deep brain stimulation of the subthalamic nucleus: histological verification and 9.4-T MRI correlation

Deep brain stimulation of the subthalamic nucleus- histological verification and 9

Acta Neurochir (2015) 157:2143–2147

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) using an MRI-guided and MRI-verified technique without microelectrode recording is an effective and safe surgical treatment for patients with Parkinson’s disease (PD).

Objectives To assess the anatomical accuracy of lead placement after MRI-guided, MRI-verified STN DBS using postmortem histology and high-field MRI at 9.4 T.

Methods We conducted post-mortem analysis of a patient’s brain who had had MRI-guided, MRI-verified STN DBS for PD, using 9.4-TMRI and histology. After death, the brain was retrieved and a block including the electrode tracks down to the mesencephalon was examined with high-field MRI at 9.4 T and histological analysis.

Results High-field MRI images and corresponding histological examination showed that each electrode track ended within the intended target area, and that DBS did not cause significant neuroparenchymal tissue damage.

Conclusions This study supports the anatomical accuracy of the MRI-guided and MRI-verified method of STN DBS.

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Lumbar Disk Herniation in Children and Adolescents

Lumbar Disk Herniation in Children and Adolescents

Neurosurgery 77:954–959, 2015

Lumbar disk herniation in adults is thought to be caused by repetitive overloading and age-rated degenerative changes. However, these causes are absent in children and adolescent patients. We assume that structural malformations in the lumbar spine could predispose intervertebral disks to early degeneration and hence need to be surgically fused. This issue has never been raised before.

OBJECTIVE: To investigate the assumption that structural malformations in the lumbar spine could predispose intervertebral disks to early degeneration and hence need to be surgically fused.

METHODS: Lumbar spine configurations, including the height of the intercrestal line, the length of L5 transverse processes, and the presence of transitional vertebrae, were recorded from anteroposterior radiographs taken from 63 consecutive pediatric patients with lumbar disk herniation admitted to our hospital over a period of 8 years. Each configuration was compared in relation to the level of disk herniation. Diskectomy alone was performed in 36 cases; arthrodesis was added in the remaining 27 cases. Patients’ back and leg pain visual analog scale scores and frequency and their Oswestry Disability Index scores were recorded before surgery and at follow-up. The results were compared for assessment of outcome.

RESULTS: Patients with high intercrestal lines and long L5 transverse processes had a significantly higher incidence of L4/5 disk herniation, whereas low intercrestal line and lumbarization were associated with L5/S1 disk herniation. Patients’ visual analog scale scores, pain frequency, and Oswestry Disability Index score all improved significantly after surgery, but there was no significant difference with or without arthrodesis.

CONCLUSION: Pediatric lumbar disk herniation is significantly associated with structural malformations of the lumbar spine, but arthrodesis does not improve the clinical outcome.

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Multimodal intraoperative monitoring during intramedullary spinal cord tumor surgery

Multimodal intraoperative monitoring during intramedullary spinal cord tumor surgery

Acta Neurochir (2015) 157:2149–2155

The aim of this work is to evaluate the utility of multimodal intraoperative monitoring (IOM) during intramedullary spinal cord tumor (IMSCT) surgery in our institution, and to investigate which IOM events are likely to be encountered during critical surgical phases.

Methods Twenty-five patients who underwent IMSCT surgery with IOM were included in this study. Our multimodal IOM assessment included SSEP, mMEP, and fEMG monitoring. Positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity were assessed 24 h and 1 month after surgery. The IOM events during three main surgical phases were also investigated. For mMEP assessment, two warning criteria (>50 % decrease in mMEP amplitude and all-or-none mMEP amplitude presence) were employed.

Results Long-term outcome prediction was better when the all-or-none criterion was applied than when the >50 % amplitude decrease criterion was applied. Based on the all-or-none criterion, the PPV, NPV, sensitivity, and specificity were 60, 100, 100, and 91 %. Frequent IOM events were observed during the three major main surgical phases. Seven (29 %) patients showed SSEP events during opening of the spinal cord. During tumor removal, 21 of 25 patients (84 %) had IOMevents, and 13 of 18 (72 %) of the fEMGevents occurred prior to the mMEP events.

Conclusions Based on the association of fEMG events with upcoming mMEP events during tumor removal, we recommend inclusion of fEMG monitoring in IOM. Multimodal IOM provides useful electrophysiological information during IMSCT surgery, especially during the main surgical phases.

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Reliability assessment of a novel cervical spine deformity classification system

Cervical spine deformity classification

J Neurosurg Spine 23:673–683, 2015

Despite the complexity of cervical spine deformity (CSD) and its signifi cant impact on patient quality of life, there exists no comprehensive classification system. The objective of this study was to develop a novel classification system based on a modified Delphi approach and to characterize the intra- and interobserver reliability of this classification.

Methods: Based on an extensive literature review and a modified Delphi approach with an expert panel, a CSD classification system was generated. The classification system included a deformity descriptor and 5 modifiers that incorporated sagittal, regional, and global spinopelvic alignment and neurological status. The descriptors included: “C,” “CT,” and “T” for primary cervical kyphotic deformities with an apex in the cervical spine, cervicothoracic junction, or thoracic spine, respectively; “S” for primary coronal deformity with a coronal Cobb angle ≥ 15°; and “CVJ” for primary craniovertebral junction deformity. The modifiers included C2–7 sagittal vertical axis (SVA), horizontal gaze (chin-brow to vertical angle [CBVA]), T1 slope (TS) minus C2–7 lordosis (TS-CL), myelopathy (modified Japanese Orthopaedic Association [mJOA] scale score), and the Scoliosis Research Society (SRS)-Schwab classification for thoracolumbar deformity. Application of the classification system requires the following: 1) full-length standing posteroanterior (PA) and lateral spine radiographs that include the cervical spine and femoral heads; 2) standing PA and lateral cervical spine radiographs; 3) completed and scored mJOA questionnaire; and 4) a clinical photograph or radiograph that includes the skull for measurement of the CBVA. A series of 10 CSD cases, broadly representative of the classification system, were selected and sufficient radiographic and clinical history to enable classification were assembled. A panel of spinal deformity surgeons was queried to classify each case twice, with a minimum of 1 intervening week. Inter- and intrarater reliability measures were based on calculations of Fleiss k coefficient values.

Results: Twenty spinal deformity surgeons participated in this study. Interrater reliability (Fleiss k coefficients) for the deformity descriptor rounds 1 and 2 were 0.489 and 0.280, respectively, and mean intrarater reliability was 0.584.

For the modifiers, including the SRS-Schwab components, the interrater (round 1/round 2) and intrarater reliabilities (Fleiss k coef cients) were: C2–7 SVA (0.338/0.412, 0.584), horizontal gaze (0.779/0.430, 0.768), TS-CL (0.721/0.567, 0.720), myelopathy (0.602/0.477, 0.746), SRS-Schwab curve type (0.590/0.433, 0.564), pelvic incidence–lumbar lordosis (0.554/0.386, 0.826), pelvic tilt (0.714/0.627, 0.633), and C7–S1 SVA (0.071/0.064, 0.233), respectively. The parameter with the poorest reliability was the C7–S1 SVA, which may have resulted from differences in interpretation of positive and negative measurements.

Conclusions: The proposed classification provides a mechanism to assess CSD within the framework of global spinopelvic malalignment and clinically relevant parameters. The intra- and interobserver reliabilities suggest moderate agreement and serve as the basis for subsequent improvement and study of the proposed classification.

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Atlanto-occipital Instability Following Endoscopic Endonasal Approach for Lower Clival Lesions

Atlanto-occipital Instability Following Endoscopic Endonasal Approach for Lower Clival Lesions

Neurosurgery 77:888–897, 2015

The endoscopic endonasal approach (EEA) for craniocervical lesions involving the lower clivus and occipital condyles carries an unclear risk of atlantooccipital (AO) instability requiring arthrodesis.

OBJECTIVE: Elucidate risk factors for AO instability following EEA for clival lesions.

METHODS: We reviewed patients with clival tumors who underwent EEA at our institution between 2002 and 2012. Resection of the lower clivus, foramen magnum, AO joint, and occipital condyles were evaluated on fine-cut postoperative computed tomography.

RESULTS: Two hundred twelve patients (mean age 47.9 years, 57.1% male) underwent transclival EEA for lower clival lesions. In addition to the lower clivus, resection involved the condyle in 14.2% of patients, the foramen magnum in 16.5%, and the AO joint in 1.4%. Quantification of condyle resection revealed complete resection in 3 cases, 75% resection in 8 cases, 50% resection in 6 cases, and 25% resection in 13 cases. Seven of these patients had EEA combined with an open, far-lateral approach. In total, 7 patients required arthrodesis following EEA (3.3%), 4 of them after a combined approach. All patients who underwent arthrodesis had primary bone tumors such as chordoma, chondrosarcoma, or osteosarcoma (P = .022). Degree of condyle resection was a significant factor predisposing to occipitocervical instability (P = .001 and P < .001 for 75% and 100% condyle resection, respectively). Use of a combined approach was significantly associated with arthrodesis (P < .001).

CONCLUSION: EEA resection of the occipital condyles that results in greater than 75% condyle resection or EEA in combination with an open approach significantly increases the risk of AO instability and likely necessitates AO fixation.

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Extended endoscopic endonasal transclival clipping of posterior circulation aneurysms

Extended endoscopic endonasal transclival clipping of posterior circulation aneurysms

Acta Neurochir (2015) 157:2077–2085

Transcranial clipping of most posterior circulation aneurysms is one of the most difficult procedures, with high morbidity, and endovascular coiling is an alternative with less risk, but is not devoid of complications and not suitable for all aneurysms. Here we describe four cases of posterior circulation aneurysms clipped via the extended endoscopic endonasal transclival route. To the best of our knowledge, this is the first report of basilar top and posterior cerebral artery aneurysms being clipped endonasally.

Methods and results Four patients with posterior circulation aneurysms underwent extended endoscopic endonasal transclival clipping of the aneurysm. The age range was 35– 70 years. There were two males and two females. Three of the four patients presented after the rupture of aneurysms, and the other patient presented with sudden-onset left hemiparesis probably due to thromboembolism from a large unruptured left posterior cerebral artery (PCA) aneurysm. On evaluation with four-vessel digital subtraction angiography (DSA), two patients had a basilar apex aneurysm, one had a basilar trunk aneurysm, and the other had a PCA (P1) aneurysm. Postoperatively, two patients had good recovery. One patient with a PCA aneurysm and another with a basilar apex aneurysm had fresh postoperative deficits. One patient developed postoperative CSF rhinorrhea.

Conclusion Endoscopic extended transnasal surgery is an expanding field in neurosurgery with a steep learning curve. With improvement in techniques and instrumentation the use of this approach for clipping posterior circulation aneurysms can become an effective alternative in the treatment of aneurysms.

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Seizure Outcomes in Patients With Surgically Treated Cerebral Arteriovenous Malformations

ICG and AVM

Neurosurgery 77:762–768, 2015

Epilepsy is the second most common symptom in cerebral arteriovenous malformation (AVM) patients. The consecutive reduction of life quality is a clinically underrated problem because treatment usually focuses on the prevention of intracerebral hemorrhage.

OBJECTIVE: To evaluate postoperative seizure outcome with the aim of more accurate counseling for postoperative seizure outcome.

METHODS: From 1985 to 2012, 293 patients with an AVM were surgically treated by J.S. One hundred twenty-six patients with preoperative seizures or epilepsy could be identified; 103 of 126 had a follow-up of at least 12 months and were included in the analysis. The different epilepsy subtypes were categorized (sporadic seizures, chronic epilepsy, drug-resistant epilepsy [DRE]). Preoperative workup and surgical technique were evaluated. Seizure outcome was analyzed by using International League Against Epilepsy classification.

RESULTS: Sporadic seizures were identified in 41% of patients (chronic epilepsy and DRE were identified in 36% and 23%, respectively). Detailed preoperative epileptological workup was done in 13%. Seizure freedom was achieved in 77% (79% at 5 years, 84% at 10 years). Outcome was significantly poorer in DRE cases. More extensive resection was performed in 11 cases with longstanding symptoms (.24 months) and resulted in better seizure outcome as well as the short duration of preoperative seizure history.

CONCLUSION: Patients presenting with AVM-associated epilepsy have a favorable seizure outcome after surgical treatment. Long-standing epilepsy and the progress into DRE markedly deteriorate the chances to obtain seizure freedom and should be considered an early factor in establishing the indication for AVM removal.

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Morphological aspects of blister aneurysms and nuances for surgical treatment

blister aneurysms

J Neurosurg 123:1156–1165, 2015

Blister aneurysms of the supraclinoid part of the internal carotid artery (ICA) are known for their high morbidity and mortality rates related to treatment, regardless of whether the treatment is surgical or endovascular. However, this grim prognosis is based on results that indiscriminately group all blister aneurysms together without taking into account the heterogeneous appearance of these lesions. The goal of this study was 2-fold: to determine whether different blister aneurysm morphologies present different pitfalls, which would then require different surgical strategies, as well as to determine whether there are identifiable subgroups of these types of aneurysms based on morphology.

Methods The authors reviewed the charts, cerebral catheter angiograms, surgical reports, and intraoperative videos of all ICA blister aneurysms treated surgically at the Centre Hospitalier de l’Université de Montréal from 2005 to 2012 to investigate whether there was a relationship between morphology and pitfalls, and whether different surgical strategies had been used according to these pitfalls. During this review process the authors noted 4 distinct morphological aspects. These 4 aspects led to a review of the English and French literature on blister aneurysms in which imaging was available, to determine whether other cases could also be classified into the same 4 subgroups based on these morphological aspects.

Results The retrospective review of the authors’ series of 10 patients allowed a division into 4 distinct subtypes: Type I (classic), Type II (berry-like), Type III (longitudinal), and Type IV (circumferential). These subtypes may at times be progressive stages in the arterial anomaly, and could represent a continuum. Each subtype described in this paper presented its own pitfalls and required specific surgical adaptations. Upon reviewing the literature the authors retained 35 studies involving a total of 61 cases of blister aneurysms, and all cases were able to be classified into 1 of these 4 distinct subtypes.

Conclusions Although they share some common characteristics, blister aneurysms may be divided into distinct subtypes, suggestive of a continuum. Such a classification with a detailed description of each type of blister aneurysm would allow for better recognition to anticipate complications during intervention and better assess the different treatment strategies according to the subtypes.

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Neurocognitive Changes Associated With Surgical Resection of Left and Right Temporal Lobe Glioma

Temporal lobe tumor

Neurosurgery 77:777–785, 2015

Little is known regarding the neurocognitive impact of temporal lobe tumor resection.

OBJECTIVE: To clarify subacute surgery-related changes in neurocognitive functioning (NCF) in patients with left (LTL) and right (RTL) temporal lobe glioma.

METHODS: Patients with glioma in the LTL (n = 45) or RTL (n = 19) completed comprehensive pre- and postsurgical neuropsychological assessments. NCF was analyzed with 2-way mixed design repeated-measures analysis of variance, with hemisphere (LTL or RTL) as an independent between-subjects factor and pre- and postoperative NCF as a within-subjects factor.

RESULTS: About 60% of patients with LTL glioma and 40% with RTL lesions exhibited significant worsening on at least 1 NCF test. Domains most commonly impacted included verbal memory and executive functioning. Patients with LTL tumor showed greater decline than patients with RTL tumor on verbal memory and confrontation naming tests. Nonetheless, over one-third of patients with RTL lesions also showed verbal memory decline.

CONCLUSION: In patients with temporal lobe glioma, NCF decline in the subacute postoperative period is common. As expected, patients with LTL tumor show more frequent and severe decline than patients with RTL tumor, particularly on verbally mediated measures. However, a considerable proportion of patients with RTL tumor also exhibit decline across various domains, even those typically associated with left hemisphere structures, such as verbal memory. While patients with RTL lesions may show even greater decline in visuospatial memory, this domain was not assessed. Nonetheless, neuropsychological assessment can identify acquired deficits and help facilitate early intervention in patients with temporal lobe glioma.

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