M Bigder

Failed microvascular decompression surgery for hemifacial spasm due to persistent neurovascular compression: an analysis of reoperations

OBJECT Microvascular decompression (MVD) surgery for hemifacial spasm (HFS) is potentially curative. The findings at repeat MVD in patients with persistent or recurrent HFS were analyzed with the aim to identify factors that may improve surgical outcomes. METHODS Intraoperative findings were determined from review of dictated operative reports and operative diagrams for patients who underwent repeat MVD after prior surgery elsewhere. Clinical follow-up was obtained from the hospital and clinic records, as well as telephone questionnaires. RESULTS Among 845 patients who underwent MVD performed by the senior author, 12 had been referred after prior MVD for HFS performed elsewhere. Following repeat MVD, all patients improved and complete spasm resolution was described by 11 of 12 patients after a mean follow-up of 91 ± 55 months (range 28-193). Complications were limited to 1 patient with aggravation of preexisting hearing loss and mild facial weakness and 1 patient with aseptic meningitis without sequelae. Significant factors that may have contributed to the failure of the first surgery included retromastoid craniectomies that did not extend laterally to the sigmoid sinus or inferiorly to the posterior fossa floor in 11 of 12 patients and a prior surgical approach that focused on the cisternal portion of the facial nerve in 9 of 12 patients. In all cases, significant persistent neurovascular compression (NVC) was evident and alleviated more proximally on the facial root exit zone (fREZ). CONCLUSIONS Most HFS patients will achieve spasm relief with thorough alleviation of NVC of the fREZ, which extends from the pontomedullary sulcus root exit point to the Obersteiner-Redlich transition zone.

Demographics, Interests, and Quality of Life of Canadian Neurosurgery Residents

BACKGROUND Neurosurgical residents face a unique combination of challenges, including long duty hours, technically challenging cases, and uncertain employment prospects. We sought to assess the demographics, interests, career goals, self-rated happiness, and overall well-being of Canadian neurosurgery residents. METHODS A cross-sectional survey was developed and sent through the Canadian Neurosurgery Research Collaborative to every resident enrolled in a Canadian neurosurgery program as of April 1, 2016. RESULTS We analyzed 76 completed surveys of 146 eligible residents (52% response rate). The median age was 29 years, with 76% of respondents being males. The most popular subspecialties of interest for fellowship were spine, oncology, and open vascular neurosurgery. The most frequent self-reported number of worked hours per week was the 80- to 89-hour range. The majority of respondents reported a high level of happiness as well as stress. Sense of accomplishment and fatigue were reported as average to high and overall quality of life was low for 19%, average for 49%, and high for 32%. Satisfaction with work-life balance was average for 44% of respondents and was the only tested domain in which significant dissatisfaction was identified (18%). Overall, respondents were highly satisfied with their choice of specialty, choice of program, surgical exposure, and work environment; however, intimidation was reported in 36% of respondents and depression by 17%. CONCLUSIONS Despite a challenging residency and high workload, the majority of Canadian neurosurgery residents are happy and satisfied with their choice of specialty and program. However, work-life balance, employability, resident intimidation, and depression were identified as areas of active concern.

Operative Landscape at Canadian Neurosurgery Residency Programs

Background Currently, the literature lacks reliable data regarding operative case volumes at Canadian neurosurgery residency programs. Our objective was to provide a snapshot of the operative landscape in Canadian neurosurgical training using the trainee-led Canadian Neurosurgery Research Collaborative. METHODS Anonymized administrative operative data were gathered from each neurosurgery residency program from January 1, 2014, to December 31, 2014. Procedures were broadly classified into cranial, spine, peripheral nerve, and miscellaneous procedures. A number of prespecified subspecialty procedures were recorded. We defined the resident case index as the ratio of the total number of operations to the total number of neurosurgery residents in that program. Resident number included both Canadian medical and international medical graduates, and included residents on the neurosurgery service, off-service, or on leave for research or other personal reasons. RESULTS Overall, there was an average of 1845 operative cases per neurosurgery residency program. The mean numbers of cranial, spine, peripheral nerve, and miscellaneous procedures were 725, 466, 48, and 193, respectively. The nationwide mean resident case indices for cranial, spine, peripheral nerve, and total procedures were 90, 58, 5, and 196, respectively. There was some variation in the resident case indices for specific subspecialty procedures, with some training programs not performing carotid endarterectomy or endoscopic transsphenoidal procedures. CONCLUSIONS This study presents the breadth of neurosurgical training within Canadian neurosurgery residency programs. These results may help inform the implementation of neurosurgery training as the Royal College of Physicians and Surgeons residency training transitions to a competence-by-design curriculum.

Extensive Mirror-Image Neurofibromas of Entire Spine Resulting in Spastic Tetraplegia

Neurofibromatosis 1 (NF1) is associated with increased incidence of spinal tumors including neurofibromas. The majority of NF1-associated spine neurofibromas are asymptomatic; however, a minority of patients will experience neurologic symptoms that can range from mild paresthesia, radiculopathy, myelopathy, and focal weakness to quadriplegia in extreme cases. We present a 21-year-old male diagnosed with NF1 in infancy and followed for multiple mirror-image neurofibromas involving the entire spine. He was asymptomatic until age 14 when he developed neck pain and progressive tetraplegia with magnetic resonance imaging showing severe cord compression secondary to bilateral C2 neurofibromas. Emergent cervical decompression was performed at C1-C3 along with debulking of bilateral neurofibromas. Postoperatively he regained full strength with no signs of myelopathy several years postoperatively. This case demonstrates a dramatic neuroimaging finding and emphasizes the potential for significant neurologic deterioration in previously asymptomatic NF1 patients, highlighting the need for long-term follow-up.

Necrotizing Teflon Granuloma After Microvascular Decompression and Gamma Knife

Microvascular decompression surgery is a commonly performed operation for the treatment of trigeminal neuralgia in which the culprit vessel is mobilized away from the trigeminal nerve root and held in place by a Teflon implant. Although generally considered to be an inert substance, the Teflon implant used inmicrovascular decompression surgery has been implicated in rare instances of granuloma formation following implantation. We report a case of a 77-year-old female with remote history of breast cancer and mastectomy who was referred to our center for evaluation and treatment of an unusual mass lesion located in the posterior fossa (Figure 1). She had an onset of trigeminal neuralgia beginning in 2000 for which she underwent a microvascular decompression in 2006; a shredded Teflon felt implant was placed between the culprit superior cerebellar artery and the underlying trigeminal nerve root. Of note, we occasionally use fibrin glue in conjunction with the shredded Teflon implant; however, this was not used in this case and not used routinely. She received limited pain relief and in 2007 underwent a Gamma Knife procedure in which an 80-Gy dose was prescribed to the proximal trigeminal nerve root. Neither computed tomography nor magnetic resonance imaging demonstrated any abnormality aside from the Teflon implant. She experienced minimal, delayed pain relief, and continued with medical management until undergoing radiofrequency rhizotomy in 2009, which provided minimal pain relief. This also resulted in corneal anesthesias and 80% preservation of sensation in V1 and V2 distributions and full preservation of V3. Over the ensuing years, she developed a progressive full sensory loss of all three trigeminal nerve distributions, temporalis and masseter muscle atrophy, accompanied by alleviation of her neuralgia. In 2015, she developed a progressive gait ataxia with magnetic resonance imaging revealing a lobulated, enhancing 2.2 × 1.8× 1.6 cm mass in the region of the previously inserted Teflon implant along with significant edema involving adjacent brain. Based on the clinical presentation and imaging findings, the differential diagnosis included metastasis, meningioma, chronic infectious process involving Teflon implant, inflammatory or granulomatous lesion, and radiation-induced pathology. Given her progressive gait ataxia along with unknown diagnosis, we elected to proceed with posterior fossa exploration through a retrosigmoid craniectomy with the goal of alleviation of mass effect and tissue sampling for diagnosis. The lesion was noted to have a firm capsule surrounding the inner contents of the tumor, consisting of soft white material intermixedwith the Teflon implants. The lesionwas adherent to the cerebellum, pons, trigeminal root entry zone, and superior cerebellar artery. After internal debulking and meticulous dissection of the tumor from the neurovascular structures, a thin rim of residual tumor was left adherent to the nerve and superior cerebellar artery. The patient tolerated the procedure well and left hospital after several days with no new deficits. At 6-month follow-up, she reported a mild improvement of her gait instability however still required the use of a four-wheel walker for mobility. Neuropathology investigation revealed mixed inflammatory infiltrates in a dense collagenous tissue (Figure 2). The infiltrate was composed of lymphocytes, histiocytes, neutrophils, and plasma cells. Multiple necrotic foci were noted, which were likely associated with previous Gamma Knife treatment. No microorganisms were demonstrated on both hematoxylin and eosin stain, as well as special stains for bacterial (Gram stain), fungal (Grocott’s methenamine silver stain), or mycobacterial (Ziehl-Neelsen stain). Based on the absence of microorganisms, it is reasonable to conclude that granulomatous inflammation was associated with the Teflon implant. This case represents an interesting presentation, management, and histopathology of a rarely reported lesion associated with a Teflon implant several years after microvascular decompression and

Trigeminal neuropathy associated with an enlarging arachnoid cyst in Meckel’s cave: case report, management strategy and review of the literature

We describe a rare case and novel management strategy of painful trigeminal neuropathy caused by an arachnoid cyst confined to Meckel’s cave. A 57-year-old female presented with several years of progressive trigeminal pain and signs of trigeminal deafferentation, including sensory loss, corneal anesthesia and mastication muscle atrophy. Medical treatment with carbamazepine provided partial and temporary pain control. Surgical treatment was eventually performed by aspiration of the arachnoid cyst through the foramen ovale using a percutaneous approach. The patient experienced relief of pain and improvement of numbness and muscle strength. To our knowledge, this is the first case description of a percutaneous drainage of a Meckel’s cave arachnoid cyst.

Nail-gun injury through the spinal canal

A 27-year-old man presented to our trauma centre after having sustained an accidental nail-gun injury resulting in a penetrating wound to the left lateral aspect of his neck. He arrived to hospital via ambulance with cervical spinal precautions in place. Upon arrival he was found to be hemodynamically stable and neurologically intact. He described an initial transient ‘electric’ like sensation in his arms and legs at the time of the accident, which promptly resolved and was no longer present at the time of arrival. A computed tomogram (CT) angiogram was performed to assess the relationship between the nail, vertebral, and carotid arteries as well as the spinal canal. The nail measured 3.5 cm and was noted to pass posteriorly, in close proximity to the vertebral artery, through the left C1-C2 neural foramen (Figure 1A, Figure 2B), coming to rest with the tip of the nail in the centre of the spinal canal (Figure 1B, Figure 2A). Based on the CT, there did not appear to be any barbs on the nail. Remarkably, there was no evidence of injury to the vertebral arteries on imaging and the patient remained neurologically intact. Following initial imaging, the patient was transferred to the operating room and the nail was removed without complications by simply pulling along the trajectory of the nail. A CT angiogram was repeated immediately following removal and showed no injury to the major vessels, hemorrhage or pseudomeningocele (Figure 3). At two-month follow-up, the patient was asymptomatic with no signs of complication or infection.

169 microvascular Decompression for Hemifacial Spasm: Analysis of Surgical Failures and Repeat Surgery

Hemifacial spasm (HFS) is a condition of debilitating, involuntary contractions of facial muscles with an estimated prevalence of 11/100 000. The potentially curative microvascular decompression surgery (MVD) aims to alleviate compression upon the facial nerve root entry zone (fREZ) by mobilizing culprit vessels and maintaining them off the nerve with implant material. Surgery is undertaken in less than 10% of sufferers across North America, such that few centers have a concentrated volume of MVD experience. We examined the operative findings and outcomes of repeat surgery after failed MVD for HFS. A database of over 700 MVDs performed by the senior author was reviewed to identify patients undergoing repeat surgery for HFS where the original surgery was performed elsewhere. Intraoperative findings were obtained from operative reports and diagrams. Outcomes were determined from hospital records and telephone questionnaires. Twelve HFS patients were identified and all were found to have persisting vascular compression on the fREZ not identified or alleviated at initial surgery. In 2 cases the prior implant material was found in the region of the fREZ but not alleviating the culprit vascular compression. In 9 cases there was no evidence of exploration or implant material at the fREZ but rather more distally on the cisternal portion of the nerve. In 1 case, there was no evidence of any implant material. Repeat surgery was successful in decompressing the fREZ in all 12 cases and postoperatively all improved. At a mean follow-up of 64 months (3-180), 10 patients reported complete resolution of spasms, 1 reported >75% and another >50% spasm reduction. No patients had major permanent complications, although 1 patient had new onset of mild facial weakness and 1 patient developed aseptic meningitis with subsequent full resolution of symptoms. Failure of MVD to cure HFS is related to inadequate identification and alleviation of vascular compression upon the affected fREZ. Repeat surgery was successful at a high-volume center.