Needs, Roles, and Challenges of Young Latin American and Caribbean Neurosurgeons.

BACKGROUND: Barriers to neurosurgery training and practice in Latin American and Caribbean countries (LACs) have been scarcely documented. The World Federation of Neurosurgical Societies Young Neurosurgeons Forum survey sought to identify young neurosurgeons' needs, roles, and challenges. We present the results focused on Latin America and the Caribbean. METHODS: In this cross-sectional study, we analyzed the Young Neurosurgeons Forum survey responses from LACs, following online survey dissemination through personal contacts, social media, and neurosurgical societies' e-mailing lists between April and November 2018. Data analysis was performed using Jamovi version 2.0 and STATA version 16. RESULTS: There were 91 respondents from LACs. Three (3.3%) respondents practiced in high-income countries, 77 (84.6%) in upper middle-income countries, 10 (11%) in lower middle-income countries, and 1 (1.1%) in an unclassified country. The majority (77, or 84.6%) of respondents were male, and 71 (90.2%) were younger than 40. Access to basic imaging modalities was high, with access to computed tomography scan universal among the survey respondents. However, only 25 (27.5%) of respondents reported having access to imaging guidance systems (navigation), and 73 (80.2%) reported having access to high-speed drills. A high GDP per capita was associated with increased availability of high-speed drills and more time dedicated to educational endeavors in neurosurgery, such as didactic teaching and topic presentation (P < 0.05). CONCLUSIONS: This survey found that neurosurgery trainees and practitioners of Latin America and the Caribbean face many barriers to practice. These include inadequate state-of-the-art neurosurgical equipment, a lack of standardized training curricula, few research opportunities, and long working hours.

Cerebrovascular Complications of Vestibular Schwannoma Surgery.

Objective Cerebrovascular complications (CVC) are rare consequences of vestibular schwannoma (VS) surgery. Our objective was to assess incidences of findings suggestive of postoperative CVC in a large single surgeon cohort, as well as potential risk factors, and implications. Study Design A cohort of 591 patients was retrospectively reviewed. Postoperative magnetic resonance images were screened for findings suggestive of stroke, T2 hyperintensity in the cerebellopontine angle structures or new encephalomalacia. Clinical records were queried for findings consistent with postoperative CVC. Results In total, 61 patients had radiographic findings consistent with possible postoperative CVC (10%); of them, eight had documented intraoperative vascular injury (1.4%), and four had postoperative clinical exam changes indicative of CVC (0.7%). Clinically manifest intraoperative vascular injuries occurred in four patients and involved the petrosal venous complex ( n = 3, 5%) or anterior inferior cerebellar artery ( n = 1, 2%); clinical deficits included hemiparesis ( n = 1, 2%), facial anesthesia ( n = 2, 4%), dysphagia ( n = 2, 2%), and unfavorable facial nerve function in two (50%). Three out of four patients in this group required out-of-home placement (75%). Clinical CVCs ( n = 4) were not significantly associated with tumor size, tumor cyst, gross total resection, or length of stay. Patients with clinical CVC were significantly more likely to require posthospitalization rehabilitation (19 vs. 75%, p = 0.02; 14 vs. 100%, p = 0.0002). Conclusion Although radiographic findings suggestive of CVC were unexpectedly common in this cohort, intraoperative vascular injury and postoperative clinical CVC were exceedingly rare. The association between unfavorable facial nerve outcome and clinical CVC is likely a marker for more difficult operations, predisposing to higher risk of complications.

Value of intraoperative monitoring of the trigeminal nerve in detection of a superiorly displaced facial nerve during surgery for large vestibular schwannomas.

The aim of this study was to investigate the role of trigeminal and facial nerve monitoring in the early identification of a superiorly (anterior and superior (AS)) displaced facial nerve. This prospective study included 24 patients operated for removal of large vestibular schwannomas (VS). The latencies of the electromyographic (EMG) events recorded from the trigeminal and facial nerve innervated muscles after mapping the superior surface of the tumor were analyzed. The mean latency of the recorded compound muscle action potential (CMAP) from the masseter muscle was 3.6 ± 0.5 ms and of the peripherally transmitted responses by volume conduction from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles was 4.6 ± 0.9, 4.1 ± 0.7, 3.9 ± 0.4, 4.3 ± 0.8, and 4.5 ± 0.6 ms, respectively, after trigeminal nerve stimulation in 24 (100%) patients (pattern I response). In 6 (25%) patients, the mean latency of CMAP on the masseter was 3.3 ± 0.3 ms, and the latencies of the CMAP from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles were 6.5 ± 1.3, 5.0 ± 1.5, 7.5 ± 1.3, 7.4 ± 0.6, and 7.0 ± 1.5 ms, respectively, longer than those of the peripherally transmitted responses (p = 0.002, p = 0.001, p < 0.001, and p = 0.015, respectively) indicating simultaneous stimulation of both nerves (pattern II response). All patients with this response were later confirmed to have an AS-displaced facial nerve. Recognizing the response resulting from simultaneous stimulation of both the facial and trigeminal nerves is important to help early identification of an AS-displaced facial nerve before it is visible in the surgical field and to avoid misleading information by confusing this pattern for a pure trigeminal nerve response.

Role of Fused Three-Dimensional Time-of-Flight Magnetic Resonance Angiography and 3-Dimensional T2-Weighted Imaging Sequences in Neurovascular Compression.

BACKGROUND: To evaluate role of fused 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) and 3-dimensional constructive interference in steady state (3D-CISS) in neurovascular compression in trigeminal neuralgia (TN) and hemifacial spasm (HFS). MATERIAL AND METHODS: A prospective study was conducted on 30 patients (mean age 47.20 ± 11.69 years), 17 (56.7%) male and 13 (43.3%) female, with TN and HFS. 3D-TOF-MRA and 3D-CISS sequences of the cerebellopontine angle were performed, as well as postprocessing with fusion of the images. Two independent readers assessed the degree of neurovascular conflict. The images were evaluated for site, signal, and degree of nerve compression and the offending vessel. The kappa test for interobserver agreement was done. RESULTS: The interobserver agreement of both readers was excellent for degree of compression (k = 0.70, 95% confidence interval [CI] 0.49-0.92, r = 0.856, P = 0.001), excellent for the side affected (k = 1.0, 95% CI = 1.0-1.0, r = 1.000, P = 0.001), excellent for the offending vessel (k = 0.85, 95% CI = 0.66-1.0, P = < 0.001), and excellent for the position of the offending vessel (k = 0.685, 95% CI = 0.489-0.882, r = 0.863, P ≤ 0.001). There was no significant correlation between the degree of compression and signal intensity. CONCLUSIONS: Fused 3D-TOF-MRA and 3D-CISS images are a reliable, noninvasive tool for the evaluation of offending vessel and degree of affection in patients with neurovascular compression. MRA-CISS can be used for evaluation and treatment planning of neurovascular compression in TN and HFS.

Socioeconomic restraints and brain tumor surgery in low-income countries.

Healthcare spending has become a grave concern to national budgets worldwide, and to a greater extent in low-income countries. Brain tumors are a serious disease that affects a significant percentage of the population, and thus proper allocation of healthcare provisions for these patients to achieve acceptable outcomes is a must. The authors reviewed patients undergoing craniotomy for tumor resection at their institution for the preceding 3 months. All the methods used for preoperative planning, intraoperative management, and postoperative care of these patients were documented. Compromises to limit spending were made at each stage to limit expenditure, including low-resolution MRI, sparse use of intraoperative monitoring and image guidance, and lack of dedicated postoperative neurocritical ICU. This study included a cohort of 193 patients. The average cost from diagnosis to discharge was $1795 per patient (costs are expressed in USD). On average, there was a mortality rate of 10.5% and a neurological morbidity rate of 14%, of whom only 82.2% improved on discharge or at follow-up. The average length of stay at the hospital for these patients was 9.09 days, with a surgical site infection rate of only 3.5%. The authors believe that despite the great number of financial limitations facing neurosurgical practice in low-income countries, surgery can still be performed with reasonable outcomes.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on Surgical Resection for the Treatment of Patients With Vestibular Schwannomas.

QUESTION 1: What surgical approaches for vestibular schwannomas (VS) are best for complete resection and facial nerve (FN) preservation when serviceable hearing is present? RECOMMENDATION: There is insufficient evidence to support the superiority of either the middle fossa (MF) or the retrosigmoid (RS) approach for complete VS resection and FN preservation when serviceable hearing is present. QUESTION 2: Which surgical approach (RS or translabyrinthine [TL]) for VS is best for complete resection and FN preservation when serviceable hearing is not present? RECOMMENDATION: There is insufficient evidence to support the superiority of either the RS or the TL approach for complete VS resection and FN preservation when serviceable hearing is not present. QUESTION 3: Does VS size matter for facial and vestibulocochlear nerve preservation with surgical resection? RECOMMENDATION: Level 3: Patients with larger VS tumor size should be counseled about the greater than average risk of loss of serviceable hearing. QUESTION 4: Should small intracanalicular tumors (<1.5 cm) be surgically resected? RECOMMENDATION: There are insufficient data to support a firm recommendation that surgery be the primary treatment for this subclass of VSs. QUESTION 5: Is hearing preservation routinely possible with VS surgical resection when serviceable hearing is present? RECOMMENDATION: Level 3: Hearing preservation surgery via the MF or the RS approach may be attempted in patients with small tumor size (<1.5 cm) and good preoperative hearing. QUESTION 6: When should surgical resection be the initial treatment in patients with neurofibromatosis type 2 (NF2)? RECOMMENDATION: There is insufficient evidence that surgical resection should be the initial treatment in patients with NF2. QUESTION 7: Does a multidisciplinary team, consisting of neurosurgery and neurotology, provides the best outcomes of complete resection and facial/vestibulocochlear nerve preservation for patients undergoing resection of VSs? RECOMMENDATION: There is insufficient evidence to support stating that a multidisciplinary team, usually consisting of a neurosurgeon and a neurotologist, provides superior outcomes compared to either subspecialist working alone. QUESTION 8: Does a subtotal surgical resection of a VS followed by stereotactic radiosurgery (SRS) to the residual tumor provide comparable hearing and FN preservation to patients who undergo a complete surgical resection? RECOMMENDATION: There is insufficient evidence to support subtotal resection (STR) followed by SRS provides comparable hearing and FN preservation to patients who undergo a complete surgical resection. QUESTION 9: Does surgical resection of VS treat preoperative balance problems more effectively than SRS? RECOMMENDATION: There is insufficient evidence to support either surgical resection or SRS for treatment of preoperative balance problems. QUESTION 10: Does surgical resection of VS treat preoperative trigeminal neuralgia more effectively than SRS? RECOMMENDATION: Level 3: Surgical resection of VSs may be used to better relieve symptoms of trigeminal neuralgia than SRS. QUESTION 11: Is surgical resection of VSs more difficult (associated with higher facial neuropathies and STR rates) after initial treatment with SRS? RECOMMENDATION: Level 3: If microsurgical resection is necessary after SRS, it is recommended that patients be counseled that there is an increased likelihood of a STR and decreased FN function. The full guideline can be found at: https://www.cns.org/guidelines/guidelines-management-patients-vestibular-schwannoma/chapter_8.

Dr Albert L. Rhoton Jr's Time at the Mayo Clinic: The Beginnings of a Remarkable Career.

Dr Albert L. Rhoton Jr became the focal point of neurosurgery's evolution in understanding the intricate and complex microanatomy of the human brain over the last 4 decades. His pioneering work on cadaveric specimens proved to be a pivotal endeavor in the pursuit to better understand the complex microsurgical anatomy of cranial surgery. This paper details his early career at the Mayo Clinic in Rochester, Minnesota. A comprehensive review and synthesis of data acquired from the institutional historical archives including the Annual Reports to the Executive Committee, the Reports to the Board of Directors, the MAYOVOX Newsletter, the illustration archives of the Mayo Clinic Division of Creative Media, staff biographies, curriculum vitae, personal interviews, as well as full-text journal articles, and book publications was performed. Dr Rhoton was engaged in a busy clinical practice as a young staff at the Mayo Clinic. Records show he focused on tackling complex intracranial pathologies along with numerous basic research and neuroanatomy projects that became a major part of his life's work and passion. He was a great teacher and friend to countless individuals and his work will continue to impact and improve the care provided to neurosurgery patients for generations to come.

Subgaleal Retention Sutures: Internal Pressure Dressing Technique for Dolenc Approach.

BACKGROUND: Extradural approach to the cavernous sinus, the "Dolenc" approach recognizing its developing Dr. Vinko Dolenc, is a critically important skull base approach. However, resection of the lateral wall of the cavernous sinus, most commonly for cavernous sinus meningiomas, results commonly in a defect that often cannot be reconstructed in a water-tight fashion. This may result in troublesome pseudomeningocele postoperatively. OBJECTIVE: To describe a technique designed to mitigate the development of pseudomeningocele. METHODS: We found the Dolenc approach critical for resection of cavernous lesions. However, a number of pseudomeningoceles were managed with prolonged external pressure wrapping in the early cohort. Therefore, we incorporated subgaleal to muscular sutures, which were designed to close this potential space and retrospectively analyzed our results. RESULTS: Twenty-one patients treated with a Dolenc approach and resection of the lateral wall of the cavernous sinus over a 2-year period were included. Prior to incorporation of this technique, 12 patients were treated and 3 (25%) experienced postoperative pseudomeningoceles requiring multiple clinic visits and frequent dressing. After incorporation of subgaleal retention sutures, no patient (0%) experienced this complication. CONCLUSION: Although basic, subgaleal to temporalis muscle retention sutures likely aid in eliminating this potential dead space, thereby preventing patient distress postoperatively. This technique is simple and further emphasizes the importance of dead space elimination in complex closures.

Predictors of 30-day perioperative morbidity and mortality of unruptured intracranial aneurysm surgery.

INTRODUCTION: Large-scale studies examining the incidence and predictors of perioperative complications after surgical clipping of unruptured intracranial aneurysms (UIA) using nationally representative prospectively collected data are lacking in the literature. METHODS: Using the American College of Surgeons' National Surgical Quality Improvement Program (ACS-NSQIP) dataset, we conducted a retrospective analysis of the complications experienced by patients that underwent surgical management of a UIA between the years of 2007 and 2013. The primary outcomes of interest were mortality within the 30-day perioperative period and adverse discharge disposition to a location other than home. Predictors of morbidity and mortality were elucidated using multivariable logistic regression analyses controlling for available patient demographic, comorbidity, and operative characteristics. RESULTS: 662 patients were identified in the ACS-NSQIP dataset for operative management of an unruptured aneurysm. The observed rates of 30-day mortality and adverse discharge disposition were 2.27% and 19.47%, respectively. A hundred and eight (16.31%) patients developed at least one major complication. On multivariable analysis, death within 30days was significantly associated with increased operative time (OR 1.005 per minute, 95% CI 1.002-1.008) and chronic preoperative corticosteroid use (OR 28.4, 95% CI 1.68-480.42), whereas major complication development was associated with increased operative time (OR 1.004 per minute, 95% CI 1.002-1.006), age (OR 1.017 per year, 95% CI 1-1.034), preoperative dependency (OR 3.3, 95% CI 1.16-9.40) and diabetes mellitus (OR 2.89, 95% CI 1.45-5.75). Lastly, increasing age (OR 1.017 per year, 95% CI 1-1.034) as well as ASA Class 3 (OR 1.73, 95% CI 1.08-2.77) and 4 (OR 2.28, 95% CI 1.1-4.72) were independent predictors of discharge to a location other than home. CONCLUSION: Our study yields morbidity and mortality benchmarks for UIA surgery in a representative, national surgical registry. It will hopefully aid in recognizing those patients at greater risk for postoperative complications following surgical management, leading to appropriate changes in treatment strategies for this selected group of patients.

Morbid obesity increases risk of morbidity and reoperation in resection of benign cranial nerve neoplasms.

OBJECTIVE: Obesity has been associated with increased risk for postoperative CSF leak in patients with benign cranial nerve tumors. Other measures of postoperative morbidity associated with obesity have not been well characterized. METHODS: Patients enrolled in the American College of Surgeons' National Surgical Quality Improvement Program (ACS-NSQIP) from 2007 to 2013 with a diagnosis code of a benign neoplasm of a cranial nerve were included. The primary outcome of postoperative morbidity was analyzed as well as secondary outcomes of readmission and reoperation. The main covariate of interest was body mass index (BMI). RESULTS: A total of 561 patients underwent surgery for a benign cranial nerve neoplasm between 2007 and 2013. Readmission data, available for 2012-2013(n=353), revealed hydrocephalus, facial nerve injury, or CSF leak requiring readmission or reoperation occurred in 0.85%, 1.42%, and 3.12%, respectively. Composite morbidity included wound complications, infection, respiratory insufficiency, transfusion requirement, stroke, venous thromboembolism, coma and cardiac arrest. On multivariable analysis patients with class I (BMI 30-34.9) and II (BMI 35-39.9) obesity showed trends towards increasing return to operating room, though not significant, but there was no trend for composite complications in class I and II obesity patients. However, class III obesity, BMI≥40, was associated with increased odds of composite morbidity (OR 4.40, 95% CI 1.24-15.88) and return to the operating room (OR 5.97, 95% CI 1.20-29.6) relative to patients with a normal BMI, 18.5-25. CONCLUSIONS: Obesity is an independent and important risk factor for composite morbidity in resection of benign cranial nerve neoplasms, and as such, merits discussion during preoperative counseling.

Suture retraction technique to prevent parent vessel obstruction following aneurysm tandem clipping.

With large or giant aneurysms, the use of multiple tandem clips can be essential for complete obliteration of the aneurysm. One potential disadvantage, however, is the considerable cumulative weight of these clips, which may lead to kinking of the underlying parent vessels and obstruction of flow. The authors describe a simple technique to address this problem, guided by intraoperative blood flow measurements, in a patient with a ruptured near-giant 2.2 × 1.7-cm middle cerebral artery bifurcation aneurysm that was treated with the tandem clipping technique. A total of 11 clips were applied in a vertical stacked fashion. The cumulative weight of the clips caused kinking of the temporal M2 branch of the bifurcation with reduction of flow. A 4-0 Nurolon suture tie was applied to the hub of one of the clips and was tethered to the dura of the sphenoid ridge by a small mini-clip and reinforced by application of tissue sealant. The patient underwent intraoperative indocyanine green videoangiography as well as catheter angiography, which demonstrated complete aneurysmal obliteration and preservation of vessel branches. Postoperative angiography confirmed patency of the bifurcation vessels with mild vasospasm. The patient had a full recovery with no postoperative complications and was neurologically intact at her 6-month follow-up. The suture retraction technique allows a simple solution to parent vessel obstruction following aneurysm tandem clipping, in conjunction with the essential guidance provided by intraoperative flow measurements.