Retrograde trans-posterior communicating artery rescue balloon angioplasty of incompletely expanded pipeline embolization device: complication management.

BACKGROUND: Pipeline embolization device (PED) deployment is a technically demanding procedure. Incomplete device expansion or deployment is one intra-operative risk, especially in patients with significant vascular tortuosity. CASE DESCRIPTION: We describe the case of a 71-year female with an unruptured left vertebral artery saccular aneurysm. Tortuosity of the arteries proximal to the aneurysm complicated deployment and the proximal end of the PED failed to expand despite several maneuvers. The inadequately expanded PED caused flow limitation in the left vertebral artery and it became imperative to achieve wall apposition of the PED. We salvaged the PED from the left vertebral artery by retrograde trans-right posterior communicating artery balloon angioplasty. CONCLUSIONS: Our case documents the successful application of the rarely used salvage strategy - anterior-to-posterior circulation retrograde rescue balloon angioplasty of an unopened PED.

Efficacy and safety of middle meningeal artery embolization in the management of refractory or chronic subdural hematomas: a systematic review and meta-analysis.

INTRODUCTION: Refractory or chronic subdural hematomas (cSDH) constitute a challenging entity that neurosurgeons face frequently nowadays. Middle meningeal artery embolization (MMAE) has emerged in the recent years as a promising treatment option. However, solid evidence that can dictate management guidelines is still lacking. METHODS: We conducted a systematic review and meta-analysis (MA) in compliance with the PRISMA guidelines to evaluate the efficacy and safety of MMAE compared with conventional treatments for refractory or cSDH. Databases were searched up to March 2019. Using a random-effects model, meta-analyses of proportions and risk difference were conducted recurrence, need for surgical rescue, and complications. RESULTS: Eleven studies (177 patients) were included. Majority (116, 69%) were males with a weighted mean age of 71 + -19.5 years. Meta-analysis of proportions showed treatment failure to be 2.8%, need for surgical rescue 2.7%, and embolization-related complications 1.2%. Meta-analysis of risk-difference between embolized and non-embolized patients showed a 26% (p < 0.001, 95% CI 21%-31%, I2 = 0) lower risk of hematoma recurrence in MMAE. Similarly, in the embolized group, the need for surgical rescue was 20% less (p < 0.001, 95% CI = 12%-27%, I2 = 12.4), and complications were 3.6% less (p = 0.008, 95% CI 1%-6%, I2 = 0) compared to conventional groups. CONCLUSIONS: Although MMAE appears to be a promising treatment for refractory or cSDH, drawing definitive conclusions remains limited by paucity of data and small sample sizes. Multicenter, randomized, prospective trials are needed to compare embolization to conventional treatments like watchful waiting, medical management, or surgical evacuation. More extensive research on MMAE could begin a new era in the minimally invasive management of cSDH.

A comparison of the techniques of direct pars interarticularis repairs for spondylolysis and low-grade spondylolisthesis: a meta-analysis.

OBJECTIVE Spondylosis with or without spondylolisthesis that does not respond to conservative management has an excellent outcome with direct pars interarticularis repair. Direct repair preserves the segmental spinal motion. A number of operative techniques for direct repair are practiced; however, the procedure of choice is not clearly defined. The present study aims to clarify the advantages and disadvantages of the different operative techniques and their outcomes. METHODS A meta-analysis was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The following databases were searched: PubMed, Cochrane Library, Web of Science, and CINAHL ( Cumulative Index to Nursing and Allied Health Literature). Studies of patients with spondylolysis with or without low-grade spondylolisthesis who underwent direct repair were included. The patients were divided into 4 groups based on the operative technique used: the Buck repair group, Scott repair group, Morscher repair group, and pedicle screw-based repair group. The pooled data were analyzed using the DerSimonian and Laird random-effects model. Tests for bias and heterogeneity were performed. The I2 statistic was calculated, and the results were analyzed. Statistical analysis was performed using StatsDirect version 2. RESULTS Forty-six studies consisting of 900 patients were included in the study. The majority of the patients were in their 2nd decade of life. The Buck group included 19 studies with 305 patients; the Scott group had 8 studies with 162 patients. The Morscher method included 5 studies with 193 patients, and the pedicle group included 14 studies with 240 patients. The overall pooled fusion, complication, and outcome rates were calculated. The pooled rates for fusion for the Buck, Scott, Morscher, and pedicle screw groups were 83.53%, 81.57%, 77.72%, and 90.21%, respectively. The pooled complication rates for the Buck, Scott, Morscher, and pedicle screw groups were 13.41%, 22.35%, 27.42%, and 12.8%, respectively, and the pooled positive outcome rates for the Buck, Scott, Morscher, and pedicle screw groups were 84.33%, 82.49%, 80.30%, and 80.1%, respectively. The pedicle group had the best fusion rate and lowest complication rate. CONCLUSIONS The pedicle screw-based direct pars repair for spondylolysis and low-grade spondylolisthesis is the best choice of procedure, with the highest fusion and lowest complication rates, followed by the Buck repair. The Morscher and Scott repairs were associated with a high rate of complication and lower rates of fusion.

Safety profile of superior petrosal vein (the vein of Dandy) sacrifice in neurosurgical procedures: a systematic review.

OBJECTIVE Walter E. Dandy described for the first time the anatomical course of the superior petrosal vein (SPV) and its significance during surgery for trigeminal neuralgia. The patient's safety after sacrifice of this vein is a challenging question, with conflicting views in current literature. The aim of this systematic review was to analyze the current surgical considerations regarding Dandy's vein, as well as provide a concise review of the complications after its obliteration. METHODS A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A thorough literature search was conducted on PubMed, Web of Science, and the Cochrane database; articles were selected systematically based on the PRISMA protocol and reviewed completely, and then relevant data were summarized and discussed. RESULTS A total of 35 publications pertaining to the SPV were included and reviewed. Although certain studies report almost negligible complications of SPV sectioning, there are reports demonstrating the deleterious effects of SPV obliteration when achieving adequate exposure in surgical pathologies like trigeminal neuralgia, vestibular schwannoma, and petroclival meningioma. The incidence of complications after SPV sacrifice (32/50 cases in the authors' series) is 2/32 (6.2%), and that reported in various case series varies from 0.01% to 31%. It includes hemorrhagic and nonhemorrhagic venous infarction of the cerebellum, sigmoid thrombosis, cerebellar hemorrhage, midbrain and pontine infarct, intracerebral hematoma, cerebellar and brainstem edema, acute hydrocephalus, peduncular hallucinosis, hearing loss, facial nerve palsy, coma, and even death. In many studies, the difference in incidence of complications between the SPV-sacrificed group and the SPV-preserved group was significant. CONCLUSIONS The preservation of Dandy's vein is a neurosurgical dilemma. Literature review and experiences from large series suggest that obliterating the vein of Dandy while approaching the superior cerebellopontine angle corridor may be associated with negligible complications. However, the counterview cannot be neglected in light of some series showing an up to 30% complication rate from SPV sacrifice. This review provides the insight that although the incidence of complications due to SPV obliteration is low, they can happen, and the sequelae might be worse than the natural history of the existing pathology. Therefore, SPV preservation should be attempted to optimize patient outcome.

Endovascular Retrieval of Migrated Distal End of Ventriculoperitoneal Shunt from Bilateral Pulmonary Arteries: A Technical Note.

Ventriculoperitoneal (VP) shunting of cerebrospinal fluid is one of the most common procedures performed by neurosurgeons around the world. Migration of distal VP shunt catheter into bilateral segmental pulmonary arteries is an extremely rare complication of VP shunt placement. In the present case, a 30-year-old male underwent VP shunting complicated by migration of distal VP shunt catheter into the bilateral pulmonary arteries. Despite manual attempt at externalizing the distal VP shunt catheter at the level of the clavicle, a small piece of distal VP shunt catheter in bilateral pulmonary arteries was noted on computed tomography of the chest obtained after manual externalization. This persistent distal VP shunt catheter was likely left behind after a break in the distal VP shunt catheter during manual externalization procedure. Given the small size of the segmental pulmonary arteries, a novel endovascular technique was used to move the distal VP shunt catheter from the bilateral segmental pulmonary arteries to the main pulmonary trunk. Once in the main pulmonary trunk, a snare device was used to retrieve the distal shunt catheter through the femoral vein. In this technical note, the authors highlight the relevant endovascular technical details to first move the VP shunt catheter from the bilateral segmental arteries followed by successful catheter retrieval using snare device.

Resection of posterior clinoid meningioma through retrosigmoid approach: concepts and nuances.

Meningiomas arising from the posterior clinoid process pose a great surgical challenge because of their location and propensity to cause critical neurovascular compression. The authors' patient was a 66-year-old female who had a large posterior clinoid meningioma with significant brainstem compression that was operated on through the retrosigmoid approach. This 3D surgical video emphasizes the various technical concepts that are important to preserving compressed neural and vascular structures during the surgery. It would also be interesting to note the extent of visualization around the posterior clinoid region gained through a retrosigmoid corridor. The video can be found here: https://youtu.be/CBmT_0ov0YA .

The 21st-century challenge to neurocritical care: the rise of the superbug Acinetobacter baumannii. A meta-analysis of the role of intrathecal or intraventricular antimicrobial therapy in reduction of mortality.

OBJECTIVE Neurosurgical infections due to multidrug-resistant organisms have become a nightmare that neurosurgeons are facing in the 21st century. This is the dawn of the so-called postantibiotic era. There is an urgent need to review and evaluate ways to reduce the high mortality rates due to these infections. The present study evaluates the efficacy of combined intravenous plus intrathecal or intraventricular (IV + IT) therapy versus only intravenous (IV) therapy in treating postneurosurgical Acinetobacter baumannii infections. METHODS The authors performed a meta-analysis of all peer-reviewed studies from the PubMed, Cochrane Library database, ScienceDirect, and EMBASE in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Five studies were finally included in the present analysis: 126 patients were studied who had postneurosurgical A. baumannii infection. The Cochrane collaboration tool was used to evaluate risk of bias, and a test of heterogeneity was performed. The I2 statistic was calculated. The patients were divided into 2 groups: the IV group received only intravenous therapy and the IV + IT group received both intravenous and intrathecal or intraventricular antimicrobial therapy. The outcome was mortality attributed specifically to A. baumannii infection in postneurosurgical cases. The pooled data were analyzed using the Cochran-Mantel-Haenszel method in a fixed-effects model. RESULTS The total number of patients in the IV-only group was 73, and the number of patients in the IV + IT group was 53. The mean duration of intravenous therapy was 27 days. The mean duration of intrathecal colistin was 21 days. The intravenous dose of colistin ranged from 3.75 to 8.8 MIU per day. The dose of intrathecal colistin ranged between 125,000 and 250,000 IU per day. The overall calculated odds ratio for mortality for the IV + IT group after pooling the data was 0.16 (95% CI 0.06-0.40, p < 0.0001). The patients who received IV + IT therapy had an 84% lower risk of dying due to the infection compared with those who received only IV therapy. CONCLUSIONS There is an 84% lower risk of mortality in patients who have been treated with combined intrathecal or intraventricular plus intravenous antimicrobial therapy versus those who have been treated with intravenous therapy alone. The intrathecal or intraventricular route should be strongly considered when dealing with postneurosurgical multidrug-resistant A. baumannii infections.

Spinal meningiomas: clinicoradiological factors predicting recurrence and functional outcome.

OBJECTIVE Spinal meningiomas are benign tumors with a wide spectrum of clinical and radiological features at presentation. The authors analyzed multiple clinicoradiological factors to predict recurrence and functional outcome in a cohort with a mean follow-up of more than 4 years. The authors also discuss the results of clinical studies regarding spinal meningiomas in the last 15 years. METHODS The authors retrospectively reviewed the clinical and radiological details of patients who underwent surgery for spinal tumors between 2001 and 2015 that were histopathologically confirmed as meningiomas. Demographic parameters, such as age, sex, race, and association with neurofibromatosis Type 2, were considered. Radiological parameters, such as tumor size, signal changes of spinal cord, spinal level, number of levels, location of tumor attachment, shape of tumor, and presence of dural tail/calcification, were noted. These factors were analyzed to predict recurrence and functional outcome. Furthermore, a pooled analysis was performed from 13 reports of spinal meningiomas in the last 15 years. RESULTS A total of 38 patients were included in this study. Male sex and tumors with radiological evidence of a dural tail were associated with an increased risk of recurrence at a mean follow-up of 51.2 months. Ventral or ventrolateral location, large tumors, T2 cord signal changes, and poor preoperative functional status were associated with poor functional outcome at 1-year follow-up. CONCLUSIONS Spine surgeons must be aware of the natural history and risk factors of spinal meningiomas to establish a prognosis for their patients.

Epidemiology of adult-onset hydrocephalus: institutional experience with 2001 patients.

OBJECTIVE Adult-onset hydrocephalus is not commonly discussed in the literature, especially regarding its demographic distribution. In contrast to pediatric hydrocephalus, which is related to a primary CSF pathway defect, its development in adults is often secondary to other pathologies. In this study, the authors investigated the epidemiology of adult-onset hydrocephalus as it pertains to different etiologies and in reference to age, sex, and race distributions. METHODS The authors retrospectively reviewed the clinical notes of 2001 patients with adult-onset hydrocephalus who presented to Louisiana State University Health Sciences Center within a 25-year span. Significant differences between the groups were analyzed by a chi-square test; p < 0.05 was considered significant. RESULTS The overall mean (± SEM) incidence of adult hydrocephalus in this population was 77 ± 30 per year, with a significant increase in incidence in the past decade (55 ± 3 [1990-2003] vs 102 ± 6 [2004-2015]; p < 0.0001). Hydrocephalus in a majority of the patients had a vascular etiology (45.5%) or was a result of a tumor (30.2%). The incidence of hydrocephalus in different age groups varied according to various pathologies. The incidence was significantly higher in males with normal-pressure hydrocephalus (p = 0.03) or head injury (p = 0.01) and higher in females with pseudotumor cerebri (p < 0.0001). In addition, the overall incidence of hydrocephalus was significantly higher in Caucasian patients (p = 0.0002) than in those of any other race. CONCLUSIONS Knowledge of the demographic variations in adult-onset hydrocephalus is helpful in achieving better risk stratification and better managing the disease in patients. For general applicability, these results should be validated in a large-scale meta-analysis based on a national population database.

Role of radiological parameters in predicting overall shunt outcome after ventriculoperitoneal shunt insertion in pediatric patients with obstructive hydrocephalus.

OBJECTIVE Despite significant advances in the medical field and shunt technology, shunt malfunction remains a nightmare of pediatric neurosurgeons. In this setting, the ability to preoperatively predict the probability of shunt malfunction is quite compelling. The authors have compared the preoperative radiological findings in obstructive hydrocephalus and the subsequent clinical course of the patient to determine any association with overall shunt outcome. METHODS This retrospective study included all pediatric patients (age < 18 years) who had undergone ventriculoperitoneal shunt insertion for obstructive hydrocephalus. Linear measurements were taken from pre- and postoperative CT or MRI studies to calculate different indices and ratios including Evans' index, frontal horn index (FHI), occipital horn index (OHI), frontooccipital horn ratio (FOHR), and frontooccipital horn index ratio (FOIR). Other morphological features such as bi- or triventriculomegaly, right-left ventricular symmetry, and periventricular lucency (PVL) were also noted. The primary clinical outcomes that were reviewed included the need for shunt revision, time interval to first shunt revision, frequency of shunt revisions, and revision-free survival. RESULTS A total of 121 patients were eligible for the analysis. Nearly half of the patients (47.9%) required shunt revision. The presence of PVL was associated with lower revision rates than those in others (39.4% vs 58.2%, p = 0.03). None of the preoperative radiological indices or ratios showed any correlation with shunt revision. Nearly half of the patients with shunt revision required early revision (< 90 days of primary surgery). The reduction in the FOHR was high in patients who required early shunt revision (20.16% in patients with early shunt revision vs 6.4% in patients with late shunt revision, p = 0.009). Nearly half of the patients (48.3%) requiring shunt revision ultimately needed more than one revision procedure. Greater occipital horn dilation on preoperative images was associated with a lower frequency of shunt revision, as dictated by a high OHI and a low FOIR in patients with a single shunt revision as compared with those in patients who required multiple shunt revisions (p = 0.029 and 0.009, respectively). The mean follow-up was 49.9 months. Age was a significant factor affecting shunt revision-free survival. Patients younger than 6 months of age had significantly less revision-free survival than the patients older than 6 months (median survival of 10.1 vs 94.1 months, p = 0.004). CONCLUSIONS Preoperative radiological linear indices and ratios do not predict the likelihood of subsequent shunt malfunction. However, patients who required early shunt revision tended to have greater reductions in ventricular volumes on postoperative images. Therefore a greater reduction in ventricular volume is not actually desirable, and a ventricular volume high enough to reduce intracranial pressure is instead to be aimed at for long-term shunt compliance.

Simulation in neurosurgery: Past, present, and future.

Neurosurgery is one of the most technically demanding medical professions that warrants a high level of expertise. In the present context of competitive medical practice, high societal expectations regarding quality of patient care and medicolegal and financial constraints, there are fewer opportunities for a trainee to achieve competency in standard neurosurgical, microsurgical, and operative techniques. Practice on simulation models like cadavers has been a trend since antiquity; however, recent development of newer models with their strategic modifications has given simulation education a new dimension. It has allowed trainees to acquire and improve surgical skills and knowledge in specifically fabricated and controlled settings with no risk to real patients. Simulation also offers the opportunity for deliberate practice and repetition unlimited number of times so that psychomotor skills can be automated. There is ever-growing evidence showing the positive impact of simulation on resident training in various areas of health care. Advances in computer technology and imaging, development of sophisticated virtual reality simulators with haptic feedback and the recent addition of three-dimensional printing technology, have opened a wide arena for the development of high-fidelity patient-specific models to complement current neurosurgical training. Simulation training in neurosurgery in India is still elementary since its inception at the All India Institute of Medical Sciences, New Delhi. A structured modular training program has been developed which is yet to be implemented at a multi-institutional level. Stringent efforts are needed to establish a uniform resident training curriculum where simulators can be used to complement current neurosurgical training.

Image-based models of T-cell distribution identify a clinically meaningful response to a dendritic cell vaccine in patients with glioblastoma.

BACKGROUND: Glioblastoma is an extraordinarily heterogeneous tumor, yet the current treatment paradigm is a "one size fits all" approach. Hundreds of glioblastoma clinical trials have been deemed failures because they did not extend median survival, but these cohorts are comprised of patients with diverse tumors. Current methods of assessing treatment efficacy fail to fully account for this heterogeneity. METHODS: Using an image-based modeling approach, we predicted T-cell abundance from serial MRIs of patients enrolled in the dendritic cell (DC) vaccine clinical trial. T-cell predictions were quantified in both the contrast-enhancing and non-enhancing regions of the imageable tumor, and changes over time were assessed. RESULTS: A subset of patients in a DC vaccine clinical trial, who had previously gone undetected, were identified as treatment responsive and benefited from prolonged survival. A mere two months after initial vaccine administration, responsive patients had a decrease in model-predicted T-cells within the contrast-enhancing region, with a simultaneous increase in the T2/FLAIR region. CONCLUSIONS: In a field that has yet to see breakthrough therapies, these results highlight the value of machine learning in enhancing clinical trial assessment, improving our ability to prospectively prognosticate patient outcomes, and advancing the pursuit towards individualized medicine.

Craniofacial Chondromyxoid Fibromas: A Systematic Review and Analysis Based on Anatomic Locations.

BACKGROUND: Craniofacial chondromyxoid fibromas (CMFs) are a rare benign tumor of cartilaginous origin. They are commonly misdiagnosed due to the paucity of information on tumor characteristics. We performed a systematic review to characterize CMFs located in different regions of the craniofacial skeleton. METHODS: A search of the literature was executed using the search phrase "chondromyxoid fibroma" and included articles from 1990-2020. Sixty-eight articles met the inclusion criteria, with a total of 91 patients with analyzable data (22 with calvarial and 69 with sinonasal tumor locations). Descriptive analyses were performed to compare pre-selected characteristics between the 2 groups. RESULTS: Sinonasal CMF frequently presented with cranial nerve palsy and expectedly had a high rate of nasal symptoms. Calvarial tumors frequently presented with an external mass and headache. Gross total resection (GTR) was achieved in a higher proportion of cases in the calvarial group versus the sinonasal group (83.3% vs. 53.1%). Overall recurrence rate at 17.7% was higher in sinonasal CMF compared with the calvarial tumors at 8.3%. Recurrences after GTR were similar in the sinonasal and calvarial groups (9.7% vs. 9.1%). In patients who did not achieve GTR, recurrence was higher in the sinonasal compared with the calvarial group (27.6% vs. 0%). CONCLUSIONS: Craniofacial CMF in calvarial and sinonasal locations have distinct clinical characteristics and response to treatment. Sinonasal lesions tend to have higher recurrence compared to calvarial CMF. Performance of GTR is associated with decreased recurrence in all CMFs.

Retromastoid Approach for Posterior Fossa Skull Base Rosai-Dorfman Disease-A Rare Pathology: 3-Dimensional Operative Video.

Rosai-Dorfman disease, originally described by Juan Rosai and Ronald F. Dorfman, is a rare benign histiocytic proliferative disorder, classically presenting with massive lymphadenopathy and a self-limiting clinical course.1 Isolated intracranial skull base involvement is extremely rare and often resembles meningiomas, schwannomas, or other benign skull base lesions.2 The disease is difficult to diagnose radiographically, and tissue diagnosis with open skull base approaches has significant perioperative risks.2,3 We present the case of a 48-yr-old Caucasian male presenting with progressively worsening headaches, giddiness, hearing difficulty, and diplopia. Magnetic resonance imaging of the brain revealed T1-weighted isointense, T2-weighted hypointense, and contrast-enhancing dural-based lesion in the left cerebellopontine angle. The patient underwent maximally safe resection of the lesion through the retromastoid approach with careful preservation of the lower cranial nerve complex. The intraoperative findings of a variegated and lobulated mass adherent to the skull base, the surgical strategy of safe resection, and eventual good outcome in this patient are depicted in this 3-dimensional video presentation. The majority of patients with skull base Rosai-Dorfman disease reported in literature have had stable or regression of disease (78%) after initial conservative surgical treatment and hence aggressive surgical resection is of unproven efficacy.3 The patient has consented to depiction of his surgical video and intraoperative images in this video manuscript.

Mechanical Thrombectomy and Thrombolysis for Dural Venous Sinus Thrombosis.

Dural venous sinus thrombosis is a rare yet major cause of stroke and mortality, especially affecting young women and children. Anticoagulation is the mainstay of therapy; however, nearly 13% of the patients experience poor outcome with anticoagulation alone.1 In addition, nearly one third of the patients with severe presentation have a risk of incomplete recovery with systemic anticoagulation.2 The subgroup of patients who have incomplete recovery or who develop rapid deterioration in spite of anticoagulation can benefit from mechanical thrombectomy with or without intrasinus thrombolysis. Our patient is a 33-year-old lady on oral contraceptive pills who developed extensive dural venous sinus thrombosis after undergoing lumboperitoneal shunt for pseudotumor cerebri (Video 1). In view of clinical deterioration despite systemic heparin therapy, we performed mechanical thrombectomy and intrasinus thrombolysis using an Angiojet device (Boston Scientific Corporation or its affiliates Inc., Marlborough, Massachusetts, USA). The Angiojet system has the unique capability of a Power Plus technique in which thrombolytic agents can simultaneously be used to facilitate clot removal. However, its utility for intracranial use is limited by the stiffness, large (6-French) catheter diameter, and short length (120 cm). After the procedure, the patient achieved rapid clinical improvement and was maintained on systemic oral anticoagulation. In addition to the case presentation, the video article also demonstrates the technical aspects of mechanical venous thrombectomy.

Posterior Interhemispheric Precuneal Approach: Fundamental Principles and Case Illustration: 3-Dimensional Operative Video.

Peritrigonal lesions are deeply seated and are surrounded by critical neurovascular structures. Traditional transcortical approaches carry the risk of damage to important surrounding white matter tracts. In this regard, a posterior interhemispheric approach gives a more direct and less invasive route and therefore is a reasonable alternative to transcortical approaches. The 3-dimensional video includes illustrations and animations showing the anatomy of the white matter tracts around the trigone and explains the physiological basis of posterior interhemispheric precuneal approach to this complex region. This also includes a 3-dimensional operative video of the same approach in a 50-yr-old male patient with left periatrial lesion describing surgical techniques and nuances. An informed written consent has been obtained from the patient.