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Background and importance Dural arteriovenous fistulas (dAVFs) are vascular abnormalities of the central nervous system that can cause a wide array of neurological dysfunction depending on their location, flow, and propensity to rupture. Symptomatic dAVFs at the cranio-cervical junction usually result in hemorrhage or cervical myelopathy. Distantly located dAVFs of the foramen magnum are a rare cause of thoracic intrinsic myelopathy. Clinical presentation An 83-yr-old man presented with progressive lower extremity weakness, numbness, and difficulty walking along with episodes of bowel incontinence. Magnetic resonance imaging of the cervical spine demonstrated multilevel cervical disc disease with stenosis and longitudinal cervical cord signal change extending into the upper thoracic spinal cord. Cerebral and spinal angiography revealed a dAVF in the lateral foramen magnum region. Given the location, feeding vasculature, and morphology of the fistula, endovascular embolization was not attempted. Microsurgical resection with confirmative indocyanine green fluorescent imaging was performed with adequate obliteration of the fistula. The patient's neurological baseline was preserved postoperatively with improvement of lower extremity numbness. Conclusion We present a brief overview of this neuropathologic entity and demonstrate microsurgical resection of a foramen magnum dAVF through operative video. Craniocervical dAVFs should remain on the differential diagnosis of patients presenting with progressive thoracolumbar myelopathy.

Lumbar spinal fusion is a commonly performed procedure to stabilize the spine, and the frequency with which this operation is performed is increasing. Multiple factors are involved in achieving successful arthrodesis. Systemic factors include patient medical comorbidities—such as rheumatoid arthritis and osteoporosis—and smoking status. Surgical site factors include choice of bone graft material, number of fusion levels, location of fusion bed, adequate preparation of fusion site, and biomechanical properties of the fusion construct. Rates of successful fusion can vary from 65 to 100%, depending on the aforementioned factors. Diagnosis of pseudoarthrosis is confirmed by imaging studies, often a combination of static and dynamic radiographs and computed tomography. Once pseudoarthrosis is identified, patient factors should be optimized whenever possible and a surgical plan implemented to provide the best chance of successful revision arthrodesis with the least amount of surgical risk.

Background Patients with Klippel-Feil syndrome may present with neurologic complaints such as neck pain, radiculopathy and gait instability. Here we describe surgical management of a patient with congenital fusion of the occipital-cervical region and also block circumferential fusion of dens to T3 with spinal cord compression. This report is the first of its kind with such extensive fusion. Case Description Our patient was a 56 year-old female, who presented with neck pain and tingling in all extremities. On exam, she had a short neck, prominent jaw with extremely limited range of motion in neck and features of myelopathy. CT showed fusion of the dens to T3 vertebrae. Patient underwent sub-occipital craniectomy, C1 laminectomy and Occiput to T5 posterior fixation and fusion with neurologic improvement. Conclusion This is the first reported case of Klippel-Feil syndrome with fusion of all cervical vertebrae down to T3. We recommend surgery for advanced cases of myelopathy or radiculopathy due to stenosis and spinal instability.

Objective Cystic vestibular schwannomas (CVSs) are anecdotally believed to have worse clinical and tumor-control outcomes than solid vestibular schwannomas (SVSs); however, no data have been reported to support this belief. In this study, we characterize the clinical outcomes of patients with CVSs versus those with SVSs. Design This is a retrospective review of prospectively collected data. Setting This study is set at single high-volume neurosurgical institute. Participants We queried a database for details on all patients diagnosed with vestibular schwannomas between January 2009 and January 2014. Main Outcome Measures Records were retrospectively reviewed and analyzed using univariate and multivariate analyses to study the differences in clinical outcomes and tumor progression or recurrence. Results Of a total of 112 tumors, 24% (n = 27) were CVSs and 76% (n = 85) were SVSs. Univariate analysis identified the extent of resection, Koos grade, and tumor diameter as significant predictors of recurrence (p ≤ 0.005). However, tumor diameter was the only significant predictor of recurrence in the multivariate analysis (p = 0.007). Cystic change was not a predictor of recurrence in the univariate or multivariate analysis (p ≥ 0.40). Postoperative facial nerve and hearing outcomes were similar for both CVSs and SVSs (p ≥ 0.47). Conclusion Postoperative facial nerve outcome, hearing, tumor progression, and recurrence are similar for patients with CVSs and SVSs. As CVS growth patterns and responses to radiation are unpredictable, we favor microsurgical resection over radiosurgery as the initial treatment. Our data do not support the commonly held belief that cystic tumors behave more aggressively than solid tumors or are associated with increased postoperative facial nerve deficits.

OBJECTIVEMinimally invasive anterolateral retroperitoneal approaches for lumbar interbody arthrodesis have distinct advantages attractive to spine surgeons. Prepsoas or transpsoas trajectories can be employed with differing complication profiles because of the inherent anatomical differences encountered in each approach. The evidence comparing them remains limited because of poor quality data. Here, the authors sought to systematically review the available literature and perform a meta-analysis comparing the two techniques.METHODSA systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A database search was used to identify eligible studies. Prepsoas and transpsoas studies were compiled, and each study was assessed for inclusion criteria. Complication rates were recorded and compared between approach groups. Studies incorporating an analysis of postoperative subsidence and pseudarthrosis rates were also assessed and compared.RESULTSFor the prepsoas studies, 20 studies for the complications analysis and 8 studies for the pseudarthrosis outcomes analysis were included. For the transpsoas studies, 39 studies for the complications analysis and 19 studies for the pseudarthrosis outcomes analysis were included. For the complications analysis, 1874 patients treated via the prepsoas approach and 4607 treated with the transpsoas approach were included. In the transpsoas group, there was a higher rate of transient sensory symptoms (21.7% vs 8.7%, p = 0.002), transient hip flexor weakness (19.7% vs 5.7%, p < 0.001), and permanent neurological weakness (2.8% vs 1.0%, p = 0.005). A higher rate of sympathetic nerve injury was seen in the prepsoas group (5.4% vs 0.0%, p = 0.03). Of the nonneurological complications, major vascular injury was significantly higher in the prepsoas approach (1.8% vs 0.4%, p = 0.01). There was no difference in urological or peritoneal/bowel injury, postoperative ileus, or hematomas (all p > 0.05). A higher infection rate was noted for the transpsoas group (3.1% vs 1.1%, p = 0.01). With regard to postoperative fusion outcomes, similar rates of subsidence (12.2% prepsoas vs 13.8% transpsoas, p = 0.78) and pseudarthrosis (9.9% vs 7.5%, respectively, p = 0.57) were seen between the groups at the last follow-up.CONCLUSIONSComplication rates vary for the prepsoas and transpsoas approaches owing to the variable retroperitoneal anatomy encountered during surgical dissection. While the risks of a lasting motor deficit and transient sensory disturbances are higher for the transpsoas approach, there is a reciprocal reduction in the risks of major vascular injury and sympathetic nerve injury. These results can facilitate informed decision-making and tailored surgical planning regarding the choice of minimally invasive anterolateral access to the spine.

Wound complications occur in up to 19% of patients undergoing complex spine surgery. The role of the plastic surgeon in complex and redo spine surgery is important and evolving. Classically, plastic surgeons have been involved in the management of patients who develop wound complications following surgery. This involves reconstruction of posterior trunk defects with locoregional fasciocutaneous, muscle, and free tissue transfers. There has also been an increasing role for plastic surgeons to become involved in prophylactic closures of complex and/or redo spine surgeries for high-risk populations. Identification of patients with comorbidities and likelihood for multiple reoperations who are prophylactically treated with complex closure with or without local muscle flaps could significantly decrease the postoperative wound complications.

Several vascularized bone grafts (VBGs) have been introduced for reconstruction and augmenting fusion of the spine. The expanding use of VBGs in the field of spinoplastic reconstruction, however, has highlighted the need to clarify the nomenclature for bony reconstruction as well as establish the position of VBGs on the bony reconstructive algorithm. In the current literature, the terms “flap” and “graft” are often applied inconsistently when describing vascularized bone transfer. Such inconsistency creates barriers in communication between physicians, confusion in interpreting the existing studies, and difficulty in comparing surgical techniques. VBGs are defined as bone segments transferred on their corresponding muscular attachments without a named major feeding vessel. The bone is directly vascularized by the muscle attachments and unnamed periosteal feeding vessels. VBGs are best positioned as a separate entity in the bony reconstruction algorithm between nonvascularized bone grafts (N-VBGs) and bone flaps. VBGs offer numerous advantages as they supply fully vascularized bone to the recipient site without the microsurgical techniques or pedicle dissection required for raising bone flaps. Multiple VBGs have been introduced in recent years to optimize these benefits for spinoplastic reconstruction.

Failed fusion in the cervical spine is a multifactorial problem stemming from a combination of patient and surgical factors. Patient-related risk factors such as steroid use, poor bone quality, and smoking can be optimized preoperatively. Age, prior radiation, prior surgery, and underlying genetics are nonmodifiable patient-centered risk factors. Surgical risks for failed fusion include the number of segments fused, anterior versus posterior approach for fusion, the type of bone graft, and the instrumentation utilized. Many symptomatic cases of failed fusion (pseudarthrosis) result in pain, neurological deficits, or loosened hardware necessitating a revision surgery consisting of extending the prior construct and utilizing additional allografts or autografts to augment the fusion. Given the relatively mobile nature of the cervical spine, pseudoarthrosis (either known or anticipated) must be recognized by the spine surgeon, and steps should be considered to optimize the likelihood of future fusion. This consists of both performing a rigid fixation and using appropriate bone graft to enhance the environment for arthrodesis. Vascularized bone grafts are a useful tool to augment fusion and provide added structural stability in cases at high risk of pseudoarthrosis.

Instrumented fixation and fusion of the thoracic spine present distinct challenges and complications including pseudarthrosis and junctional kyphosis. When complications arise, morbidity to the patient can be significant, involving neurologic injury, failure of instrumentation constructs, as well as iatrogenic spinal deformity. Causes of fusion failure are multifactorial, and incompletely understood. Most likely, a diverse set of biomechanical and biologic factors are at the heart of failures. Revision surgery for thoracic fusion failures is complex and often requires revision or extension of instrumentation, and frequently necessitates complex soft tissue manipulation to manage index level injury or to augment the changes of fusion.

Background Obtaining successful arthrodesis at the craniocervical junction and atlantoaxial joint can be more challenging than in other segments of the cervical spine. This challenge stems from the relatively hypermobile joints between the occipital condyles, the motion that occurs at C1 and C2, as well as the paucity of dorsal bony surfaces for posterior arthrodesis. While multiple different techniques for spinal fixation in this region have been well described, there has been little investigation into auxiliary methods to improve fusion rates. Objective To describe the use of an occipital bone graft to augment bony arthrodesis in the supraaxial cervical spine using a multidisciplinary approach. Methods We review the technique for harvesting and placing a vascularized occipital bone graft in 2 patients undergoing revision surgery at the craniocervical junction. Results The differentiation from nonvascularized bone graft, either allograft or autograft, to a bone graft using vascularized tissue is a key principle of this technique. It has been well established that vascularized bone heals and fuses in the spine better than structural autogenous grafts. However, the morbidity and added operative time of harvesting a vascularized flap, such as from the fibula or rib, precludes its utility in most degenerative spine surgeries. Conclusion By adapting the standard neurosurgical procedure for a suboccipital craniectomy and utilizing the tenets of flap-based reconstructive surgery to maintain the periosteal and muscular blood supply, we describe the feasibility of using a vascularized and pedicled occipital bone graft to augment instrumented upper cervical spinal fusion. The use of this vascularized bone graft may increase fusion rates in complex spine surgeries.

OBJECTIVE An advantage of lateral lumbar interbody fusion (LLIF) surgery is the indirect decompression of the neural elements that occurs because of the resulting disc height restoration, spinal realignment, and ligamentotaxis. The degree to which indirect decompression occurs varies; no method exists for effectively predicting which patients will respond. In this study, the authors identify preoperative predictive factors of indirect decompression of the central canal. METHODS The authors performed a retrospective evaluation of prospectively collected consecutive patients at a single institution who were treated with LLIF without direct decompression. Preoperative and postoperative MRI was used to grade central canal stenosis, and 3D volumetric reconstructions were used to measure changes in the central canal area (CCA). Multivariate regression was used to identify predictive variables correlated with radiographic increases in the CCA and clinically successful improvement in visual analog scale (VAS) leg pain scores. RESULTS One hundred seven levels were treated in 73 patients (mean age 68 years). The CCA increased 54% from a mean of 0.96 cm2 to a mean of 1.49 cm2 (p < 0.001). Increases in anterior disc height (74%), posterior disc height (81%), right (25%) and left (22%) foraminal heights, and right (12%) and left (15%) foraminal widths, and reduction of spondylolisthesis (67%) (all p < 0.001) were noted. Multivariate evaluation of predictive variables identified that preoperative spondylolisthesis (p < 0.001), reduced posterior disc height (p = 0.004), and lower body mass index (p = 0.042) were independently associated with radiographic increase in the CCA. Thirty-two patients were treated at a single level and had moderate or severe central stenosis preoperatively. Significant improvements in Oswestry Disability Index and VAS back and leg pain scores were seen in these patients (all p < 0.05). Twenty-five (78%) patients achieved the minimum clinically important difference in VAS leg pain scores, with only 2 (6%) patients requiring direct decompression postoperatively due to persistent symptoms and stenosis. Only increased anterior disc height was predictive of clinical failure to achieve the minimum clinically important difference. CONCLUSIONS LLIF successfully achieves indirect decompression of the CCA, even in patients with substantial central stenosis. Low body mass index, preoperative spondylolisthesis, and disc height collapse appear to be most predictive of successful indirect decompression. Patients with preserved disc height but severe preoperative stenosis are at higher risk of failure to improve clinically.

Magnetic resonance guided focused ultrasound (MRgFUS) thalamotomy is a novel and minimally invasive ablative treatment for essential tremor. The size and location of therapeutic lesions producing the optimal clinical benefits while minimizing adverse effects are not known. We examined these relationships in patients with essential tremor undergoing MRgFUS. We studied 66 patients with essential tremor who underwent MRgFUS between 2012 and 2017. We assessed the Clinical Rating Scale for Tremor (CRST) scores at 3 months after the procedure and tracked the adverse effects (sensory, motor, speech, gait, and dysmetria) 1 day (acute) and 3 months after the procedure. Clinical data associated with the postoperative Day 1 lesions were used to correlate the size and location of lesions with tremor benefit and acute adverse effects. Diffusion-weighted imaging was used to assess whether acute adverse effects were related to lesions encroaching on nearby major white matter tracts (medial lemniscus, pyramidal, and dentato-rubro-thalamic). The area of optimal tremor response at 3 months after the procedure was identified at the posterior portion of the ventral intermediate nucleus. Lesions extending beyond the posterior region of the ventral intermediate nucleus and lateral to the lateral thalamic border were associated with increased risk of acute adverse sensory and motor effects, respectively. Acute adverse effects on gait and dysmetria occurred with lesions inferolateral to the thalamus. Lesions inferolateral to the thalamus or medial to the ventral intermediate nucleus were also associated with acute adverse speech effects. Diffusion-weighted imaging revealed that lesions associated with adverse sensory and gait/dysmetria effects compromised the medial lemniscus and dentato-rubro-thalamic tracts, respectively. Lesions associated with adverse motor and speech effects encroached on the pyramidal tract. Lesions larger than 170 mm3 were associated with an increased risk of acute adverse effects. Tremor improvement and acute adverse effects of MRgFUS for essential tremor are highly dependent on the location and size of lesions. These novel findings could refine current MRgFUS treatment planning and targeting, thereby improving clinical outcomes in patients.

Background Idiopathic spinal cord herniation (ISCH) is a rare pathology of the spine defined by herniation of the spinal cord through a dural defect. Objective To highlight the operative management of ISCH and the surgical nuances of ISCH repairs conducted at our institution. Methods This retrospective review examines consecutive patients with ISCH who were treated surgically between January 1, 2010, and July 31, 2017, at Barrow Neurological Institute, Phoenix, Arizona. Results Four patients with ISCH presented with thoracic myelopathy and lower extremity weakness during the study period. Treatment consisted of reduction of the herniated spinal cord and filling of the dural defect with a collagen-based dural regeneration matrix. In 3 patients the dural edges were covered with a collagen-matrix intradural sling, and in 1 patient they were repaired primarily with interrupted sutures. Three of the 4 patients experienced improvement in myelopathic symptoms; the fourth patient suffered neurological decline in the immediate postoperative period. Conclusion ISCH is a complex pathological condition likely to result in progressive myelopathy. Surgery offers patients the possibility of stabilizing the progression of the spinal cord dysfunction and perhaps restoring neurological function. However, extreme care must be taken during surgery to minimize manipulation of the fragile herniated cord.

OBJECTIVESeizures are the most common presenting symptom of newly diagnosed WHO Grade II gliomas (low-grade glioma [LGG]) and significantly impair quality of life. Although gross-total resection of LGG is associated with better seizure control, it remains unclear whether an extent of resection (EOR) “threshold” exists for long-term seizure control. Specifically, what proportion of FLAIR-positive tissue in patients with newly diagnosed LGG must be removed to achieve Engel Class I seizure freedom? To clarify the EOR threshold for long-term seizure control, the authors analyzed data from a consecutive series of patients with newly diagnosed LGG who presented with seizures and subsequently underwent microsurgical resection.METHODSThe authors identified consecutive patients with newly diagnosed LGG who presented with seizures and were treated at the Barrow Neurological Institute between 2002 and 2012. Patients were dichotomized into those who were seizure free postoperatively and those who were not. The EOR was calculated by quantitative comparison of pre- and postoperative MRI. Univariate analysis of these 2 groups included the chi-square test and the Mann-Whitney U-test, and a multivariate logistic regression was constructed to predict the impact of multiple independent variables on the likelihood of postoperative seizure freedom. To determine a threshold of EOR that optimizes seizure freedom, a receiver operating characteristic curve was plotted and the optimal point of discrimination was determined.RESULTSData from 128 patients were analyzed (male/female ratio 1.37:1; mean age 40.8 years). All 128 patients presented with seizures, usually generalized (n = 57, 44.5%) or simple partial (n = 57, 44.5%). The median EOR was 90.0%. Of 128 patients, 46 (35.9%) had 100% volumetric tumor resection, 64 (50.0%) had 90%–99% volumetric tumor resection, and 11 (8.6%) had 80%–89% volumetric tumor resection. Postoperatively, 105 (82%) patients were seizure free (Engel Class I); 23 (18%) were not (Engel Classes II–IV). The proportion of seizure-free patients increased in proportion to the EOR. Predictive variables included in the regression model were preoperative Karnofsky Performance Scale score, seizure type, time from diagnosis to surgery, preoperative number of antiepileptic drugs, and EOR. Only EOR significantly affected the likelihood of postoperative Engel Class I status (OR 11.5, 95% CI 2.4–55.6; p = 0.002). The receiver operating characteristic curve generated based on Engel Class I status showed a sensitivity of 0.65 and 1 – specificity of 0.175, corresponding to an EOR of 80%.CONCLUSIONSFor adult patients with LGG who suffer seizures, the results suggest that seizure freedom can be attained when EOR > 80% is achieved. Improvements in both the proportion of seizure-free patients and the durability of seizure freedom were observed beyond this 80% threshold. Interestingly, this putative EOR seizure-freedom threshold closely approximates that reported for the overall survival benefit in newly diagnosed hemispheric LGGs, suggesting that a minimum level of residual tumor burden is necessary for both disease and symptomatic progression.

OBJECTIVEFusiform dolichoectatic vertebrobasilar aneurysms are rare, challenging lesions. The natural history of these lesions and medium- and long-term patient outcomes are poorly understood. The authors sought to evaluate patient prognosis after diagnosis of fusiform dolichoectatic vertebrobasilar aneurysms and to identify clinical and radiographic predictors of neurological deterioration.METHODSThe authors reviewed multiple, prospectively maintained, single-provider databases at 3 large-volume cerebrovascular centers to obtain data on patients with unruptured, fusiform, basilar artery dolichoectatic aneurysms diagnosed between January 1, 2000, and January 1, 2015.RESULTSA total of 50 patients (33 men, 17 women) were identified; mean clinical follow-up was 50.1 months and mean radiographic follow-up was 32.4 months. At last follow-up, 42% (n = 21) of aneurysms had progressed and 44% (n = 22) of patients had deterioration of their modified Rankin Scale scores. When patients were dichotomized into 2 groups— those who worsened and those who did not—univariate analysis showed 5 variables to be statistically significantly different: sex (p = 0.007), radiographic brainstem compression (p = 0.03), clinical posterior fossa compression (p < 0.001), aneurysmal growth on subsequent imaging (p = 0.001), and surgical therapy (p = 0.006). A binary logistic regression was then created to evaluate these variables. The only variable found to be a statistically significant predictor of clinical worsening was clinical symptoms of posterior fossa compression at presentation (p = 0.01).CONCLUSIONSFusiform dolichoectatic vertebrobasilar aneurysms carry a poor prognosis, with approximately one-half of the patients deteriorating or experiencing progression of their aneurysm within 5 years. Despite being high risk, intervention—when carefully timed (before neurological decline)—may be beneficial in select patients.

Background: The visualization of the subthalamic nucleus (STN) on magnetic resonance imaging (MRI) is variable. Studies of the contribution of patient-related factors and intrinsic brain volumetrics to STN visualization have not been reported previously. Objective: To assess the visualization of the STN during deep brain stimulation (DBS) surgery in a clinical setting. Methods: Eighty-two patients undergoing pre-operative MRI to plan for STN DBS for Parkinson disease were retrospectively studied. The visualization of the STN and its borders was assessed and scored by 3 independent observers using a 4-point ordinal scale (from 0 = not seen to 3 = excellent visualization). This measure was then correlated with the patients’ clinical information and brain volumes. Results: The mean STN visualization scores were 1.68 and 1.63 for the right and left STN, respectively, with a good interobserver reliability (intraclass correlation coefficient: 0.744). Older age and decreased white matter volume were negatively correlated with STN visualization (p < 0.05). Conclusion: STN visualization is only fair to good on routine MRI with good concordance of interindividual rating. Advancing age and decreased white matter are associated with poor visualization of the STN. Knowledge about factors contributing to poor visualization of the STN could alert a surgeon to modify the imaging strategy to optimize surgical targeting.

Background: Intramedullary melanocytomas are exceedingly rare and their management is largely based on case reports and small clinical series. They have characteristic imaging and histologic findings that can aid in their diagnosis. Genetic testing may be required for definitive diagnosis and management guidance in ambiguous cases. Case Description: We present the case of a thoracic intramedullary meningeal melanocytoma in a patient unable to undergo an MRI. Conclusion: This is the first reported S-100-negative case with genetic testing to support the diagnosis of a rare intramedullary melanocytoma.

Retrospective review.To compare the safety and accuracy of the freehand technique versus stereotactic navigation for placement of iliac screws.Iliac screw fixation is often used to augment lumbosacral reconstruction in advanced spine disease to increase the likelihood of successful arthrodesis. Iliac screws can be placed with image guidance, using either intraoperative fluoroscopy or computed tomography (CT) to guide navigation. However, these imaging modalities add radiation exposure and can disrupt workflow. The freehand technique is an alternative strategy that decreases radiation exposure and workflow disruption but may compromise safety and accuracy.A retrospective review was performed for a consecutive series of adult patients with degenerative spine conditions who underwent posterior reconstruction with iliac screw placement between 2011 and 2016. Clinical and radiographic data were collected and analyzed. The accuracy of iliac screw placement was determined with either intraoperative/postoperative CT imaging or anteroposterior/lateral radiography when CT was not performed.Bilateral iliac screws were placed in all 111 patients, for a total of 222 iliac screws. Eighty screws were placed with the freehand technique and 142 with the intraoperative navigation technique. CT imaging was used to assess placement accuracy of 124 screws (46 freehand [37%], 78 navigated [63%]). Accuracy was similar for the freehand group (89%, 41/46) and the navigated group (96%, 75/78) (P = 0.12). For patients without intraoperative/postoperative CT imaging, radiography was used to assess placement accuracy of 98 screws (34 freehand, 64 navigated) and the placement accuracy rate for the freehand group (100%, 34/34) was comparable to that for the navigated group (98%, 63/64) (P = 0.46). No complications attributable to iliac screw placement occurred in either group.Overall, there was no difference in the safety and accuracy between the freehand and navigated techniques.4.

Background The diagnosis and management of patients with idiopathic intracranial hypertension (IIH) frequently relies on lumbar puncture to ascertain intracranial pressure (ICP). However, ICP values derived this way may be spurious owing to patient body habitus and behavior. We recently incorporated direct continuous ICP monitoring into the work-up for IIH. Methods Through billing records, we identified all patients during a 3-year period who had a diagnosis of IIH and who underwent ICP monitoring before shunt placement or revision. Patient demographics and clinical data were reviewed. Results Of 30 patients who underwent ICP monitoring with an intraparenchymal wire, 17 had undergone lumbar puncture within the previous 6 months. Results from lumbar punctures showed an elevated opening pressure in all 17 patients, whereas only 2 patients (12%) were found to have consistently elevated ICP with direct ICP monitoring. Of 15 patients being evaluated for shunting, 4 (27%) were found to have elevated ICP. Of the 15 patients with existing shunts, 2 patients (13%) were found to have malfunctioning shunts after pressure monitoring, and 3 patients (20%) had shunts that were found to be unnecessary and were removed. No patient experienced any complication from invasive monitoring. Conclusions Direct ICP monitoring is the gold standard for determining ICP and can be safely and effectively applied to the work-up and treatment of patients with IIH to reduce the occurrence of misdiagnosis and unnecessary surgery.

Objective Some aneurysms without a definable neck and associated parent vessel pathology are particularly difficult to treat and may require clipping with circumferential wrapping. We report the largest available contemporary series examining the techniques of Gore-Tex clip-wrapping of ruptured and unruptured intracranial aneurysms and patient outcomes. Methods The presentation, location, and shape of the aneurysm; wrapping technique; outcome at discharge and last follow-up; and any change in the aneurysm at last angiographic follow-up were reviewed retrospectively in 30 patients with Gore-Tex clip-wrapped aneurysms. Results Gore-Tex clip-wrapping was used in 8 patients with ruptured aneurysms and 22 patients with unruptured aneurysms. Aneurysms included 23 fusiform, 3 blister, and 4 otherwise complex, multilobed, or giant aneurysms. Of the 30 aneurysms, 63% were in the anterior circulation. The overall mean patient age was 52.5 years (range, 17–80 years). Postoperatively, there were no deaths or worsening of neurologic status and no parent vessel stenoses or strokes. The mean Glasgow Outcome Scale score at last follow-up was 4.7. The mean follow-up time was 42.3 months (median, 37.0 months; range, 3–96 months). There were 105.8 patient follow-up years. Aneurysms recurred in 2 patients with Gore-Tex clip-wrapping. No patients developed rehemorrhage. Overall risk of recurrence was 1.9% annually. Conclusions Gore-Tex has excellent material properties for circumferential wrapping of aneurysms and parent arteries. It is inert and does not cause a tissue reaction or granuloma formation. Gore-Tex clip-wrapping can be used safely for microsurgical management of ruptured and unruptured cerebral aneurysms with acceptable recurrence and rehemorrhage rates.

OBJECTIVELateral lumbar interbody fusion (LLIF) is a useful minimally invasive technique for achieving anterior interbody fusion and preserving or restoring lumbar lordosis. However, achieving circumferential fusion via posterior instrumentation after an LLIF can be challenging, requiring either repositioning the patient or placing pedicle screws in the lateral position. Here, the authors explore an alternative single-position approach: LLIF in the prone lateral (PL) position.METHODSA cadaveric feasibility study was performed using 2 human cadaveric specimens. A retrospective 2-center early clinical series was performed for patients who had undergone a minimally invasive lateral procedure in the prone position between August 2019 and March 2020. Case duration, retractor time, electrophysiological thresholds, implant size, screw accuracy, and complications were recorded. Early postoperative radiographic outcomes were reported.RESULTSA PL LLIF was successfully performed in 2 cadavers without causing injury to a vessel or the bowel. No intraoperative subsidence was observed. In the clinical series, 12 patients underwent attempted PL surgery, although 1 case was converted to standard lateral positioning. Thus, 11 patients successfully underwent PL LLIF (89%) across 14 levels: L2–3 (2 of 14 [14%]), L3–4 (6 of 14 [43%]), and L4–5 (6 of 14 [43%]). For the 11 PL patients, the mean (± SD) age was 61 ± 16 years, mean BMI was 25.8 ± 4.8, and mean retractor time per level was 15 ± 6 minutes with the longest retractor time at L2–3 and the shortest at L4–5. No intraoperative subsidence was noted on routine postoperative imaging.CONCLUSIONSPerforming single-position lateral transpsoas interbody fusion with the patient prone is anatomically feasible, and in an early clinical experience, it appeared safe and reproducible. Prone positioning for a lateral approach presents an exciting opportunity for streamlining surgical access to the lumbar spine and facilitating more efficient surgical solutions with potential clinical and economic advantages.

Minimally invasive surgery (MIS) approaches for the correction of adult spinal deformity have gained popularity in the past decade. MIS approaches can result in decreased hospitalization times and decreased morbidity. However, compared to open techniques, MIS approaches are challenging in the setting of fixed sagittal deformity and strategic surgical staging. Combined MIS and miniopen techniques are described as "hybrid" techniques. We report on the surgical approach for a fixed sagittal deformity using both MIS and miniopen techniques, specifically a miniopen pedicle subtraction osteotomy (PSO) and an anterior column release (ACR). The patient gave written informed consent for surgical treatment; institutional review board approval was not required. The patient first underwent the placement of percutaneous modular pedicle screws from T12 to the pelvis as well as a mini-PSO across the previously fused L5 vertebral body, with the placement of a temporary rod. The following day, the patient underwent lateral transpsoas interbody fusion and ACR at L2/3; a percutaneous rod was then passed from T12 to the pelvis for segmental fixation. The patient recovered well and was discharged home without complication 6 d after the initial day of surgery. The combined use of surgical staging and traditional open techniques in a selective, minimalistic fashion and adherence to minimally invasive principles provide for a powerful set of surgical techniques that capitalize on less invasive approaches to deformity management. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Traditional open approaches to correct lumbar spine deformities include 3-column osteotomies, such as a pedicle subtraction osteotomy (PSO). Minimally invasive surgical (MIS) techniques have been developed for lateral transpsoas anterior column realignment (ACR). These 2 techniques have not previously been combined. Our objective was to investigate the cadaveric feasibility of a combined hybrid MIS ACR-PSO technique for deformity correction and to review early clinical experience.The feasibility of the combined ACR-PSO technique was evaluated in 4 fresh cadaveric specimens. The operative experience, complications, and early clinical outcomes in patients treated with the combined approach to correct global sagittal imbalance were reviewed.In the cadaveric study, the combined ACR-PSO resulted in a mean 46.0° increase in lordosis (P0.001). Nine patients treated with ACR-PSO were evaluated (mean age, 65.2 years; 33.3% female). Most patients (6/9; 66.7%) underwent ACR at L1/2 or L3/4; 8 (88.8%) had PSO at L3 or L4. On average, 10.6 ± 3.8 levels were fused. Significant decreases in mean pelvic tilt (P = 0.01), spinopelvic mismatch (P0.001), and T1 spinopelvic inclination (P = 0.03) were observed postoperatively; mean lumbar lordosis (P = 0.007), intradiscal angle (P = 0.001), and thoracic kyphosis (P = 0.04) significantly increased. The overall complication rate was 55.6% (5/9).Our early experience suggests that a combined ACR-PSO with posterior fixation allows for significant correction of segmental lordosis and global imbalance. This combined approach may maximize results attainable with hybrid MIS-open surgical techniques and represents a complementary option to PSO and other posterior approaches.

The indications for operative intervention after thoracolumbar spine trauma have been well described. Advances in minimally invasive techniques, including percutaneous pedicle screw fixation and mini-open anterolateral retractor-based approaches can improve surgical outcomes when appropriately applied by reducing blood loss, operative duration and post-operative pain. Moreover, they allow for theoretical advantages by preservation of muscular and skeletal blood supply and innervation that is typically lost during the muscular dissection of open approaches. For thoracolumbar spine fractures, percutaneous fixation allows for internal bracing of unstable fractures during healing while maintaining sagittal alignment. In instances of neurological compromise from fracture retropulsion, corpectomies may be required, and mini-open lateral approaches adopted from degenerative disease applications allow for a minimally invasive manner to treat the defect. These further allow for placement of wide rectangular-footprint expandable vertebral body replacement devices to provide anterior column support. We believe this allows for lower rates of subsidence and helps to maintain the biomechanical integrity necessary to prevent post-traumatic malalignment and kyphosis. Together, these minimally invasive techniques combined supply the spine surgeon with a minimally invasive armamentarium to treat nearly all thoracolumbar spine trauma. Surgeons should be comfortable with the strengths and shortcomings of these approaches in order to successfully apply them for this pathology.

Background The majority of Parkinson's disease patients with deep brain stimulation (DBS) use a monopolar configuration, which presents challenges for EEG and MRI studies. The literature reports algorithms to convert monopolar to bipolar settings. Purpose/hypothesis To assess brain responses of Parkinson's disease patients implanted with DBS during fMRI studies using their clinical and presumed equivalent settings using a published conversion recipe. Study type Prospective. Subjects Thirteen DBS patients. Field strength/sequence 1.5T and 3T, fMRI using gradient echo-planar imaging. Assessment Patients underwent 30/30sec ON/OFF DBS fMRI scans using monopolar and bipolar settings. To convert to a bipolar setting, the negative contact used for the monopolar configuration remained constant and the adjacent dorsal contact was rendered positive, while increasing the voltage by 30%. fMRI activation/deactivation maps and motor Unified Parkinson's Disease Rating Scale (UPDRS-III) scores were compared for patients in both configurations. Statistical tests T-tests were used to compare UPDRS scores and volumes of tissue activated (VTA) diameters in monopolar and bipolar configurations. Results The patterns of fMRI activation in the monopolar and bipolar configurations were generally different. The thalamus, pallidum, and visual cortices exhibited higher activation using the patient's clinical settings than the presumed equivalent settings. VTA diameters were lower (7 mm vs. 6.3 mm, P = 0.047) and UPDRS scores were generally higher in the bipolar (33.2 ± 16) than in the monopolar configuration (28.3 ± 17.4), without reaching statistical significance (P > 0.05). Data conclusion Monopolar and bipolar configurations result in different patterns of brain activation while using a previously published monopolar-bipolar conversion algorithm. Clinical benefits may be achieved with varying patterns of brain responses. Blind conversion from one to the other should be avoided for purposes of understanding the mechanisms of DBS. Level of evidence 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018.

Lateral interbody fusion has distinct advantages over traditional posterior approaches. When adjunctive percutaneous pedicle screw fixation is required, placement from the lateral decubitus position theoretically increases safety and improves operative efficiency by obviating the need for repositioning. However, safe cannulation of the contralateral, down-side pedicles remains technically challenging and often prohibitive. In this video, we present the case of a 59-yr-old man with refractory back pain and bilateral lower extremity radiculopathy that was worse on the left than right side. The patient provided written informed consent before undergoing treatment. We performed minimally invasive single-position lateral interbody fusion with robotic (ExcelsiusGPS, Globus Medical Inc, Audubon, Pennsylvania) bilateral percutaneous pedicle screw fixation for the treatment of asymmetric disc degeneration, dynamic instability, and left paracentral disc herniation with corresponding stenosis at the L3-4 level. A left-sided minimally invasive transpsoas lateral interbody graft was placed with fluoroscopic guidance. Without changing the position of the patient or breaking the sterile field, an intraoperative cone-beam computed tomography image was obtained for navigational screw placement with stereotactic trackers in the iliac spine. Screw trajectories were planned using the robotic navigation software and were placed percutaneously in the bilateral L3 and L4 pedicles using the robotic arm. Concomitant lateral fluoroscopy may be used if desired to ensure the fidelity of the robotic guidance. The patient recovered well postoperatively and was discharged home within 36 h, without complication. Single-position lateral interbody fusion and percutaneous pedicle screw fixation can be accomplished using robotic-assisted navigation and pedicle screw placement. Used with permission from Barrow Neurological Institute.

A frequently encountered problem during posterolateral fusion (PLF) is bone graft displacement from the posterolateral space during closure. Commercially available solutions to this problem are seldom used because of their exceptionally high cost. The purpose of this report is to describe 3 novel, low-cost techniques we developed for bone graft containment during PLF.Three low-cost bone graft containment techniques are described: rapid suture weave, makeshift bone bag, and cellulose rooftop. Early clinical experience with these techniques is reported for a 5-patient case series.One or more of these bone graft containment techniques were used in 5 patients who underwent PLF. Rapid suture weave was the least expensive ($5.00) but required the longest additional time to perform (20 minutes). Makeshift bone bag and cellulose rooftop cost approximately the same ($48.00 and $46.00, respectively); the makeshift bone bag took less additional time (3 minutes) but created a potential barrier between the bone graft and the host site, whereas the cellulose rooftop took slightly longer to perform (5 minutes) but permitted direct contact between the bone graft and host site.These 3 novel surgical techniques for bone graft containment in the posterolateral space add minimally to the cost and length of the procedure. Our early clinical experience suggests that these techniques are safe and effective. Additional clinical experience is warranted, and prospective data collection is ongoing.

OBJECTIVEMinimally invasive anterior and lateral approaches to the lumbar spine are increasingly used to treat and reduce grade I spondylolisthesis, but concerns still exist for their usage in the management of higher-grade lesions. The authors report their experience with this strategy for grade II spondylolisthesis in a single-surgeon case series and provide early clinical and radiographic outcomes.METHODSA retrospective review of a single surgeon’s cases between 2012 and 2016 identified all patients with a Meyerding grade II lumbar spondylolisthesis who underwent minimally invasive lateral lumbar interbody fusion (LLIF) or anterior lumbar interbody fusion (ALIF) targeting the slipped level. Demographic, clinical, and radiographic data were collected and analyzed. Changes in radiographic measurements, Oswestry Disability Index (ODI), and visual analog scale (VAS) scores were compared using the paired t-test and Wilcoxon signed rank test for continuous and ordinal variables, respectively.RESULTSThe average operative time was 199.1 minutes (with 60.6 ml of estimated blood loss) for LLIFs and 282.1 minutes (with 106.3 ml of estimated blood loss), for ALIFs. Three LLIF patients had transient unilateral anterior thigh numbness during the 1st week after surgery, and 1 ALIF patient had transient dorsiflexion weakness, which was resolved at postoperative week 1. The mean follow-up time was 17.6 months (SD 12.5 months) for LLIF patients and 10 months (SD 3.1 months) for ALIF patients. Complete reduction of the spondylolisthesis was achieved in 12 LLIF patients (75.0%) and 7 ALIF patients (87.5%). Across both procedures, there was an increase in both the segmental lordosis (LLIF 5.6°, p = 0.002; ALIF 15.0°, p = 0.002) and overall lumbar lordosis (LLIF 2.9°, p = 0.151; ALIF 5.1°, p = 0.006) after surgery. Statistically significant decreases in the mean VAS and the mean ODI measurements were seen in both treatment groups. The VAS and ODI scores fell by a mean value of 3.9 (p = 0.002) and 19.8 (p = 0.001), respectively, for LLIF patients and 3.8 (p = 0.02) and 21.0 (p = 0.03), respectively, for ALIF patients at last follow-up.CONCLUSIONSEarly clinical and radiographic results from using minimally invasive LLIF and ALIF approaches to treat grade II spondylolisthesis appear to be good, with low operative blood loss and no neurological deficits. Complete reduction of the spondylolisthesis is frequently possible with a statistically significant reduction in pain scores.

Background The V2 segment of the vertebral artery (VA) typically runs through the transverse foramen of C2-C6. V2 injury may occur during anterior approaches to the cervical spine and can cause significant morbidity. We describe landmarks and microsurgical V2 repair techniques through the standard anterolateral cervical diskectomy approach. Methods Five silicone-injected cadaveric heads (necks–C7) were dissected bilaterally. An anterolateral approach with C3-4, C4-5, and C5-6 diskectomies and an ipsilateral VA injury were simulated. VA approach and repair were performed using microdissection techniques. Landmarks to the VA were identified, and distances from landmarks to the VA were measured in horizontal and vertical planes. Operative photographs of stepwise approach and repair techniques were processed for stereoscopic illustration. An illustrative case describes microsurgery to successfully repair an inadvertent VA injury during a C3-C6 diskectomy and fusion procedure. Results The anatomic landmarks delineated were the intervertebral disk, uncinate apices, and anterior tubercles of C4-C6 transverse processes. After temporary hemostasis with packing, VA exposure and repair included dissection of the longus colli muscle, removal of the anterior root of the transverse processes above and below the injury level, intertransversarii muscle removal, vertebral plexus opening, VA handling, and microsuturing. In 30 dissected cadaver intertransverse intervals, 13 medial, 7 lateral, and 3 anterior branches of the V2 were encountered at C3-C6 levels. Conclusion Familiarity with relevant vascular surgical anatomy allows neurosurgeons to be prepared in cases of VA injury and may facilitate repair when the VA is injured during anterior cervical spine surgery.

Spinal arteriovenous malformations (AVMs) are a diverse population of vascular lesions associated with significant long-term morbidity and neurologic impairment. Spinal AVMs can be classified into three categories: intramedullary, extradural-intradural, and conus, depending on their angioarchitecture and anatomy. Extradural-intradural lesions are typically incurable due to their diffuse nature, but patients may benefit from targeted therapy of symptomatic components. Intramedullary and conus AVMs are amenable to safe surgical resection when combined with endovascular embolization and use of a pial dissection technique that spares entry into the neural parenchyma.

Background Hypothalamic hamartomas (HH) are rare lesions associated with treatment-resistant epilepsy. Open surgery results in modest seizure control (about 50%) but has a significant associated morbidity. Radiosurgery is limited to a subset of patients due to latent therapeutic effects. Magnetic resonance imaging-guided laser interstitial thermal therapy (LITT) offers a novel minimally invasive option. Objective To evaluate a single center's outcomes for the LITT treatment of HH. Methods We retrospectively reviewed our experience with LITT for the treatment of HH using our institution's prospectively maintained patient database. Results Eighteen patients (mean age, 21.1 yr; median age, 11 yr) underwent 21 total LITT treatments for HH. Mean follow-up was 17.4 mo. The length of stay was 1 night for 16 (89%) patients. At the end of follow-up, 11 of 18 patients (61%) had full disconnection of the HH, and 12 of 15 (80%) patients with gelastic seizures and 5 (56%) of 9 patients with nongelastic seizures were seizure free (International League Against Epilepsy Class 1). Immediate complications included a 39% (7/18) incidence of neurological deficits, including 1 case of hemiparesis. At the end of follow-up, 22% of patients (4/18) had persistent deficits. The hypothyroidism that occurred was delayed in 11% of patients (2/18), as was short-term memory loss (22%, 4/18) and weight gain (22%, 4/18). Conclusion LITT therapy for HH can achieve excellent rates of seizure control with low morbidity and a short postoperative stay in a majority of patients. Additional research is needed to assess the durability of results and the full spectrum of cognitive outcomes.

BACKGROUND CONTEXT Postural stability (PS) is closely associated with quality of life and falls in the elderly. Recent work has demonstrated impaired gait and increased falls in patients with ASD, suggesting impaired postural stability due to biomechanical constraints of the spinal deformity. However, while previous studies have investigated the effect of spinal malalignment on static balance, no previous work has specifically focused on postural stability or dynamic balance in patients with ASD, nor the sensorimotor contribution to instability. Computerized dynamic posturography (CDP) is a widely used diagnostic and prognostic tool for assessment of postural instability in diseases of gait and imbalance such as Parkinson's disease, osteoarthritis, and vestibular dysfunction. PURPOSE The objective of our study was to assess postural stability of patients with adult spinal deformity (ASD) using cCDP and (1) compare with published normative controls, (2) determine the relationship between fall status and postural stability, and (3) determine the relationship between quality of life and postural stability in ASD STUDY DESIGN/SETTING Prospective analysis of postural stability using CDP. PATIENT SAMPLE Eleven consecutive patients with severe adult spinal deformity who were seen and evaluated in an outpatient clinic. OUTCOME MEASURES Equilibrium scores (ES) during Sensory Organization Testing (SOT) across 6 conditions with varying sensorimotor deprivation, motor latency during Motor Control Testing (MCT), and a history of falls in community setting. METHODS Eleven patients with ASD were prospectively enrolled. Inclusion criteria: coronal cobb (CC)≥20°, Pelvic incidence-lumbar lorodsis (PI-LL) >10°, sagittal vertical axis (SVA) ≥5 cm, pelvic tilt (PT)≥25°, and thoracic kyphosis (TK)≥60°. Exclusion criteria: inability to stand, presence of confounding neurological conditions. PS was determined using two randomly assigned tests with CDP: (1) SOT to evaluate the voluntary use of sensory information; and (2) motor control test (MCT) to assess involuntary postural reactions in response to external perturbations. Patient performance was compared to age-gender matched controls. QOL metrics included SRS-22 and SF-36 RESULTS Mean age was 65±4.6, and 6/13 (46%) were female. Mean PI-LL was 31.2±12.7, PT 32.8±8.0, SVA 11.8±6.3 cm, TK 27.3±16.6, and CC 14.5±16.7. Four patients reported falling in the previous 6 months (36%). Those patients who self reported falling in past 6 months demonstrated significantly lower SOT (Conditions 2–6, p CONCLUSIONS ASD patients demonstrate impaired postural stability and dynamic balance compared to normal controls. Further, postural stability and QOL metrics correlated with self-reported falls. These findings suggest that ASD patients have drastically altered balance, which predisposes these patients to elevated risk of falls and injury as well as decreased ambulatory confidence and quality of life.

BACKGROUND CONTEXT Postoperative pain control following posterior spinal fusion surgery remains a struggle for providing physicians. Poorly controlled pain can result in physiological dysfunction and emotional distress with undesired outcomes, and has been tied to poor patient satisfaction with their treatment. Additionally, there is a demand to decrease opioid prescription and utilization in the acute postoperative period as a means of preventing addiction/chronic use and opioid-related adverse events that may prolong hospital stay. Multimodal pain treatment regimens have been well-demonstrated in other surgical disciplines to improve pain outcomes and decrease opiate requirements. PURPOSE The goal of the study was to objectively evaluate the change in outcomes that occurs with the usage of a multimodal pain treatment plan. We hypothesized that standardized application would improve postoperative pain control in lumbar spinal fusion patients. STUDY DESIGN/SETTING Single-institution retrospective comparative cohort study. PATIENT SAMPLE All patients receiving open, posterior, lumbar fusion surgery at our institution between July 2016 and June 2017 were eligible. Patients treated for degenerative conditions were included, and large operations for the treatment of scoliosis or adult spinal deformity were not included. Patients treated with minimally invasive surgery, or anterior-posterior operations were excluded. Patients receiving surgery for traumatic, infections or neoplastic etiologies were also excluded. OUTCOME MEASURES Patient-reported, postoperative NRS pain scores were used to determine pain metrics, including mean pain score, highest pain score and time until pain satisfactorily managed. Opioid consumption was measured for patients in the first 72 hours after surgery. Hospital length of stay and opioid-related adverse events were secondary outcome measures. METHODS An evidence-based, multidisciplinary quality improvement initiative was implemented to standardize pain treatment following neurosurgical procedures at our institution. A retrospective chart review was conducted to evaluate pain-related outcomes during the last six months before and the first six months after implementation of the multimodal treatment regimen. The protocol included scheduled dosing of acetaminophen, NSAIDs (ibuprofen or ketorolac), muscle relaxants (methocarbamol), topical lidocaine patches, as needed dosing of gabapentinoids, and opioid delivery as needed for rescue. RESULTS A total of 115 pre- and 126 postimplementation patients were identified. The cohorts were well-matched with no differences in sex, age, surgical duration, number of segments fused, preoperative pain level or baseline physical status (all p>.05). Average patient-reported pain scores significantly improved in the first 24 hours postoperatively (5.8 vs. 4.6, p CONCLUSIONS Implementation of an evidence-based, standardized multi-modal pain protocol led to a reduction in pain scores, opioid consumption, opioid-related adverse events, and length of hospital stay after posterior lumbar fusion. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Cavernous malformations of the brain are low-flow vascular lesions that have a propensity to hemorrhage. Extensive surgical approaches are often required for operative cure of deep-seated lesions. A 23-year-old female presented with a cavernous malformation of the left posterior insula with surrounding hematoma measuring up to 3 cm. A minimally invasive (mini-)pterional craniotomy with a transsylvian approach was selected. Endoscopic assistance was utilized to confirm complete resection of the lesion. The minipterional craniotomy is a minimally invasive approach that provides optimal exposure for sylvian fissure dissection and resection of many temporal and insular lesions.The video can be found here: https://youtu.be/9z6_EhU6lxs.

BACKGROUND AND IMPORTANCE We present a unique case of an anterior cranial base von Hippel-Lindau disease (VHL)-associated microcystic neoplasm. To determine the lesion's relationship with VHL and its appropriate management, we discuss its salient clinical, pathological, and molecular features. CLINICAL PRESENTATION A 36-year-old woman with VHL presented with a 3-month history of phantosmia. Serial magnetic resonance imaging studies revealed a lesion within the ethmoid and frontal sinus region that was first evident 18 months before symptom development and demonstrated progressive growth over the interval period. The lesion was resected via a transbasal approach. Histopathological and immunohistochemical analysis revealed a microcystic lesion composed of bland clear cells and underlying endothelial cells consistent with a VHL-associated microcystic neoplasm that are not known to metastasize. Molecular testing demonstrated loss of heterozygosity of the VHL locus, verifying the tumor as a VHL-related neoplasm. CONCLUSION Because primary VHL-associated microcystic tumors in the anterior cranial base have not been described previously, the natural history of these tumors remains unclear. Based on the benign features of these lesions, they can be managed conservatively with close observation and surgical intervention reserved for those that produce symptoms.

Background and importance Vein of Galen aneurysmal malformations (VGAMs) arise from persistent arteriovenous shunting from primitive choroidal vessels into the median prosencephalic vein of Markowski, the embryonic precursor of the vein of Galen. VGAMs rarely present past infancy, and their natural history in adults is unknown. We report the first case of a familial-associated VGAM in an asymptomatic adult female patient. The clinical features of this case are presented alongside a systematic review of the literature on adult VGAM cases to assess the natural history, clinical management, and genetic basis of this rare neurovascular lesion. Clinical presentation A previously healthy 44-year-old woman with a family history of a VGAM in a stillborn presented with an 8-week onset of dizziness and vertigo that spontaneously resolved. Time-resolved magnetic resonance angiography identified a choroidal VGAM. No intervention was undertaken at this time because of the patient's asymptomatic status after 9 months of follow-up. Conclusion Based on our review of the literature, this is the first case report of a familial-associated VGAM in an adult patient and suggests that VGAM development can be genetically linked. Of 15 adult VGAM cases previously reported, all patients were either symptomatic or treated, thus precluding determination of VGAM natural history in adults. Patient outcomes correlated with the severity of presenting symptoms, which ranged from asymptomatic to immediately life-threatening. We hypothesize that self-selection may render VGAMs to be more benign for them to persist past childhood. Further investigation of the molecular biology underlying VGAM development is warranted.

OBJECTIVEThe aim of this article is to review the authors’ and published experience with deep brain stimulation (DBS) therapy for the treatment of patients with Alzheimer’s disease (AD) and Parkinson’s disease dementia (PDD).METHODSTwo targets are current topics of investigation in the treatment of AD and PDD, the fornix and the nucleus basalis of Meynert. The authors reviewed the current published clinical experience with attention to patient selection, biological rationale of therapy, anatomical targeting, and clinical results and adverse events.RESULTSA total of 7 clinical studies treating 57 AD patients and 7 PDD patients have been reported. Serious adverse events were reported in 6 (9%) patients; none resulted in death or disability. Most studies were case reports or Phase 1/2 investigations and were not designed to assess treatment efficacy. Isolated patient experiences demonstrating improved clinical response after DBS have been reported, but no significant or consistent cognitive benefits associated with DBS treatment could be identified across larger patient populations.CONCLUSIONSPDD and AD are complex clinical entities, with investigation of DBS intervention still in an early phase. Recently published studies demonstrate acceptable surgical safety. For future studies to have adequate power to detect meaningful clinical changes, further refinement is needed in patient selection, metrics of clinical response, and optimal stimulation parameters.

Background The external carotid artery (ECA) anastomoses in many distal territories supplied by the internal carotid artery (ICA) and is an important source of collateral circulation to the brain. Stenosis of the ECA in ipsilateral ICA occlusion can produce ischemic sequelae. Objective To examine the effectiveness of ECA stenting in treating symptomatic ipsilateral ICA occlusion. Methods We retrospectively reviewed patient databases from 5 academic medical centers to identify all individuals who underwent ECA stenting after 1998. For all discovered cases, coinvestigators used a common submission form to harvest relevant demographic information, clinical data, procedural details, and follow-up results for further analysis. Results Twelve patients (median age, 66 years; range, 45-79 years) were identified for our cohort. Vessel disease involvement included severe ECA stenosis >or= 70% in 11 patients and ipsilateral ICA occlusion in all patients. Presenting symptoms included signs of transient ischemic attack, stroke, and amaurosis fugax. ECA stenting was associated with preservation of neurological status in 11 patients and resolution of symptoms in 5 patients at a median follow-up time of 26 months (range, 1-87 months; mean, 29 months). Symptomatic in-stent restenosis did not occur within any patient during the follow-up course. Conclusion We found ECA stenting in symptomatic ipsilateral ICA disease to be a potentially effective strategy to preserve neurological function and to relieve ischemic symptoms. Further investigation with larger studies and longer follow-up periods is warranted to elucidate the true indications of this management strategy.

Lumbar interbody fusion involves insertion of a structural graft into an intervertebral disc space to promote bony arthrodesis. It is a well-established surgical strategy for multiple spinal disorders ranging from degenerative conditions to trauma, neoplastic diseases, and deformities requiring correction. Since the inception of lumbar interbody fusion, the most established techniques have been two posterior approaches, the posterior lumbar interbody fusion (PLIF) and the transforaminal lumbar interbody fusion (TLIF). Within the past 15 years, multiple anterolateral approaches to the spine have become widely adopted. These approaches can be performed minimally invasively and spare disruption of the paraspinal muscles and posterior spinal column while enabling wide exposure of the disc space for insertion of interbody grafts much larger than PLIF and TLIF instrumentation. This review highlights three minimally invasive anterolateral approaches: the anterior lumbar interbody fusion (ALIF), the transpsoas lateral lumbar interbody fusion (LLIF), and prepsoas or anterior to the psoas oblique lumbar interbody fusion (OLIF). Relevant topics for discussion and comparison include patient selection, surgical techniques, outcomes, and complications for the three surgical approaches.

Background The far-lateral transcondylar surgical approach is often used to clip vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms. The role of condyle resection during this approach is controversial. Objective To evaluate patient outcomes in patients with VA-PICA aneurysms in whom drilling the occipital condyle was not necessary. Methods Between May 2005 and December 2012, a total of 56 consecutive patients with incidental or ruptured VA-PICA aneurysms underwent surgery with a far-lateral approach without condylar resection. Clinical presentation, surgical reports, presurgery and postsurgery radiological examinations, and clinical follow-up reports were assessed. Anatomic aneurysm location was analyzed through angiography or computed tomography angiography. We compared postsurgical Glasgow Outcome Scale scores, modified Rankin Scale scores, and morbidity in 2 groups: those with aneurysms in the anterior medullary segment and those with aneurysms in the lateral medullary segment. Results The predominant presentation was subarachnoid hemorrhage in 34 patients (60.7%). Most aneurysms (n = 27 [48.2%]) were located in the lateral medullary segment of the PICA, followed by the anterior medullary segment (n = 25 [44.6%]). Total aneurysm occlusion was achieved in 100% of patients, and bypass techniques were necessary in 3 patients (5.4%). Fifty-two patients (92.8%) had Glasgow Outcome Scale scores of 4 or 5 postsurgery. Conclusions A far-lateral approach that leaves the occipital condyle intact is adequate for treating most patients with VA-PICA aneurysms.

Background Intracranial hemangioblastomas are highly vascular tumors that account for 1% to 2% of all central nervous system tumors. Preoperative embolization has been proposed to limit the often significant intraoperative blood loss associated with resection and potentially make the tumor more soft/necrotic and thus more amenable to gross total resection. The safety and efficacy of preoperative embolization of intracranial hemangioblastomas, however, are not well characterized. Objective To evaluate the safety and efficacy of preoperative endovascular embolization of intracranial hemangioblastomas using a variety of embolic agents. Methods A retrospective review of all surgically resected intracranial hemangioblastomas treated with preoperative embolization between 1999 and 2014 at 2 high-volume centers was performed. Clinical and radiographic criteria, including von Hippel-Lindau status, magnetic resonance imaging tumor characteristics, embolization-related complications, degree of angiographic devascularization, intraoperative blood loss, ability to obtain gross total resection, transfusion requirements, and operative time, were analyzed. Results A total of 54 patients underwent surgery, with 24 undergoing preoperative embolization followed by surgical resection, and 30 patients undergoing surgical resection alone. Embolization-related neurological complications were seen in 6 patients (25%), including 3 hemorrhages when polyvinyl alcohol particles (P = .04) were used and 3 infarctions when liquid embolic agents were used (P = .27). Permanent neurological deficits were seen in 15%. Conclusion Preoperative embolization of intracranial hemangioblastomas should be performed with caution, given the potential for neurological morbidity. Further studies are needed to help guide patient and embolic agent selection.

Object The authors aimed to systematically review the literature to clarify the natural history of brain arteriovenous malformations (BAVMs). Methods The authors searched PubMed for one or more of the following terms: natural history, brain arteriovenous malformations, cerebral arteriovenous malformations, and risk of rupture. They included studies that reported annual rates of hemorrhage and that included either 100 patients or 5 years of treatment-free follow-up. Results The incidence of BAVMs is 1.12–1.42 cases per 100,000 person-years; 38%–68% of new cases are first-ever hemorrhage. The overall annual rates of hemorrhage for patients with untreated BAVMs range from 2.10% to 4.12%. Consistently implicated in subsequent hemorrhage are initial hemorrhagic presentation, exclusively deep venous drainage, and deep and infrantentorial brain location. The risk for rupture seems to be increased by large nidus size and concurrent arterial aneurysms, although these factors have not been studied as thoroughly. Venous stenosis has not been implicated in increased risk for rupture. Conclusions For patients with BAVMs, although the overall risk for hemorrhage seems to be 2.10%–4.12% per year, calculating an accurate risk profile for decision making involves clinical attention and accounting for specific features of the malformation.

Background/Objective: Decisions to use open surgery or radiotherapy in pediatric patients with familial neoplastic syndromes must consider not only the symptomatic benefits of treatment, but also future limitations these treatments may impose. Specifically, open surgical resection of noncurable tumors may preclude or encumber future lesion resections, while radiotherapy has detrimental effects on pediatric cognitive development and increases the risk of future malignancy development. We provide the first report of using a novel 3.0-mm diffusing laser tip with laser-induced thermal therapy (LiTT) to treat a pediatric patient with neurofibromatosis type 1 (NF-1). Methods: A 12-year-old boy with NF-1 presented with a progressively enlarging lesion in the right midbrain. A stereotactic biopsy was performed, followed by LiTT with a novel 3.0-mm laser applicator. Results: MRI 1 week after LiTT showed stable gross total ablation of the lesion with reduction in fluid-attenuated inversion recovery signal. The patient remained neurologically intact 6 months after his procedure, and follow-up MRI showed no evidence of recurrence. Conclusion: LiTT is a powerful adjunct to conventional open surgical and radiotherapy modalities in the treatment of patients with familial neoplastic syndromes or incurable lesions. The novel laser applicator tip described expands the treatment scope of this technique.

Glioblastoma multiforme is the most common and malignant primary brain tumor. Recent evidence indicates that a subset of glioblastoma tumor cells have a stem cell like phenotype that underlies chemotherapy resistance and tumor recurrence. We utilized a new "multidimensional" capillary isoelectric focusing nano-reversed-phase liquid chromatography platform with tandem mass spectrometry to compare the proteomes of isolated glioblastoma tumor stem cell and differentiated tumor cell populations. This proteomic analysis yielded new candidate proteins that were differentially expressed. Specifically, two isoforms of the membrane proteolipid neuronatin (NNAT) were expressed exclusively within the tumor stem cells. We surveyed the expression of NNAT across 10 WHO grade II and III gliomas and 23 glioblastoma (grade IV) human tumor samples and found NNAT was expressed in a subset of primary glioblastoma tumors. Through additional in vitro studies utilizing the U87 glioma cell line, we found that expression of NNAT is associated with significant increases in cellular proliferation. Paralleling the in vitro results, when NNAT levels were evaluated in tumor specimens from a consecutive cohort of 59 glioblastoma patients, the presence of increased levels of NNAT were found to be a an independent risk factor (P = 0.006) for decreased patient survival through Kaplan-Meier and multivariate analysis. These findings indicate that NNAT may have utility as a prognostic biomarker, as well as a cell-surface target for chemotherapeutic agents.

To investigate the impact of cardiac donor participation in high-risk social behaviors (HRSBs) on recipient survival.Retrospective chart review queried cardiac transplantations performed at our institution from August 1994 to November 2007 involving donors known to have engaged in HRSBs. Kaplan-Meier methodology was used to analyze survival rates, and a Cox proportional hazards regression was performed to determine the impact of donor HRSBs on survival.We identified 143 donors with social histories containing the following HRSBs: incarceration (n=69), unprofessional tattoos or piercings (n=44), alternative lifestyle practice (n=11), cocaine use (n=60), heroin smoking (n=6), marijuana use (n=79), oral narcotic abuse (n=20), and intravenous drug use (n=21). At the time of donation, viral screens detected 10 donors who were hepatitis B virus (HBV) positive, 11 donors who were hepatitis C virus (HCV) positive, and no donors who were positive for the HIV. One-year and 5-year survival were 92.2% and 84.4%, respectively. Cox regression analysis found only donor HCV infection to be associated with poorer recipient survival (P=0.14).Using cardiac allografts from high-risk donors who are serologically negative for viruses does not seem to impact recipient survival. There is a considerable risk for transmission of HBV and HCV when these are detected by pretransplant screens. However, if pretransplant screening does not discover donor HBV, HCV, or HIV infection, it is unlikely that subclinical disease transmission will occur.