Frameless image-guided linear accelerator (LINAC) stereotactic radiosurgery for medically refractory trigeminal neuralgia: Clinical outcomes in 116 patients.

Background: Frameless image-guided radiosurgery (IGRS) is an effective and non-invasive method of treating patients who are unresponsive to medical management for trigeminal neuralgia (TN). This study evaluated the use of frameless IGRS to treat patients with medically refractory TN. Methods: We performed a retrospective review of records of 116 patients diagnosed with TN who underwent frameless IGRS using a linear accelerator (LINAC) over 10 years (March 2012-February 2023). All patients had failed medical management for TN. Facial pain was graded using the Barrow Neurological Institute (BNI) scoring system. Each patient received a BNI score before frameless IGRS and following treatment. Failure was defined as a BNI score IV-V at the last follow-up and/or undergoing a salvage procedure following IGRS. Results: All patients had a BNI score of either IV or V before the frameless IGRS. The mean follow-up duration for all 116 patients following IGRS was 44.1 months. Most patients (81 [69.8%]) had not undergone surgery (microvascular decompression [MVD] or rhizotomy) or stereotactic radiosurgery (SRS) for TN before frameless IGRS. A total of 41 (35.3%) patients underwent a salvage procedure (MVD, rhizotomy, or an additional IGRS) following frameless IGRS. The mean duration between the initial frameless IGRS and salvage procedure was 20.1 months. At the last follow-up, a total of 110 (94.8%) patients had a BNI score of I-III. No complications were reported after the frameless IGRS. The BNI score at the last follow-up was lower compared to the initial BNI for patients regardless of prior intervention (P < 0.001). Patients who failed IGRS had a higher BNI score at the last follow-up compared to those who did not fail IGRS (2.8 vs. 2.5, P = 0.05). Patients with pain relief had a shorter follow-up compared to those with pain refractory to SRS (38.0 vs. 55.1, P = 0.005). Conclusion: In this large cohort of patients with medically refractory TN, frameless IGRS resulted in durable pain control in the majority of patients without any toxicity.

Role of electromyography and ultrasonography in the diagnosis of double crush lumbar radiculopathy and common fibular injury: illustrative cases.

BACKGROUND: Double crush syndrome consists of two compression sites along a peripheral nerve and is rare in the lower extremities. Electrodiagnostic and ultrasound (US) studies may be helpful in evaluating foot drop involving overlapping pathologies. OBSERVATIONS: Case 1 involved a man who presented with left dorsiflexor weakness and left foot numbness. Electromyography (EMG) revealed a left common fibular nerve entrapment neuropathy and left L5 radiculopathy. US and magnetic resonance imaging (MRI) revealed a large cystic lesion of the left common fibular nerve treated by cyst removal. The left foot drop persisted postoperatively. Lumbar computed tomography myelography revealed severe left foraminal stenosis at L5-S1. Multilevel lumbar laminectomies and facetectomies with an L5-S1 fusion were performed. Within 1 month postoperatively, the left foot drop had improved. Case 2 involved a man who developed a right foot drop caused by right lumbar foraminal stenosis at L4-5 and L5-S1. EMG and US of the right common fibular neuropathy showed large fascicles involving the right common fibular nerve. MRI revealed a hyperintense signal of the right common fibular nerve. Spontaneous improvement occurred within 6 months without surgery. LESSONS: Spine surgeons should recognize double crush in the lower extremities. EMG and US are valuable in detecting peripheral nerve abnormalities, especially in cases with overlapping lumbar pathology.

Varied Presentation and Importance of MR Neurography of the Common Fibular Nerve in Slimmer's Paralysis.

Slimmer's paralysis refers to a common fibular nerve palsy caused by significant and rapid weight loss. This condition usually results from entrapment of the common fibular nerve due to loss of the fat pad surrounding the fibular head. Several etiologies of common fibular nerve palsy have been proposed, including trauma, surgical complications, improperly fitted casts or braces, tumors and cysts, metabolic syndromes, and positional factors. We present 5 cases of slimmer's paralysis in patients who had lost 32-57 kg in approximately 1 year. In 2 cases, MR neurogram of the knee demonstrated abnormalities of the common fibular nerve at the fibular head. Two patients underwent a common fibular nerve decompression at the fibular head and attained improved gait and sensorimotor function. Weight loss, diabetes mellitus, and immobilization may have contributed to slimmer's paralysis in 1 case. Awareness of slimmer's paralysis in patients who have lost a significant amount of weight in a short period of time is imperative to detect and treat a fibular nerve neuropathy that may ensue.

Venipuncture-Related Median Nerve Palsy Disguised as Intraoperative Brachial Plexus Injury.

Iatrogenic peripheral nerve injuries may result from transection, stretch, compression, injections, ligature, heat, anticoagulant use, and radiation. Iatrogenic median nerve palsy has been reported rarely. We report a case of a woman who underwent craniectomy for treatment of trigeminal neuralgia. Intraoperatively, a transient decline in the amplitude of the left upper extremity somatosensory evoked potentials (SSEPs) was noted. This finding was presumed to be due to the traction on the brachial plexus as it improved with repositioning. Immediately upon waking from anesthesia, the patient experienced sensorimotor deficits in the left median nerve distribution. Ecchymoses from venipuncture were observed in this area. Electrodiagnostic studies confirmed a left median nerve neuropathy localized in the antebrachial area. Neurosurgeons and neurologists should be alert to potential iatrogenic median nerve palsy following vascular access at the antebrachial region. Vascular access could be performed under the ultrasound guidance when a patient is under anesthesia or unable to give sensory feedback. Furthermore, placing an additional recording electrode over the proximal upper arm during intraoperative SSEP monitoring aids in distinguishing between brachial plexus and peripheral nerve injuries.

Balancing Operative Efficiency and Surgical Education: A Functional Neurosurgery Model.

BACKGROUND: Attending surgeons have dual obligations to deliver high-quality health care and train residents. In modern healthcare, lean principles are increasingly applied to processes preceding and following surgery. However, surgeons have limited data regarding variability and waste during any given operation. OBJECTIVE: To measure variability and waste during the following key functional neurosurgery procedures: retrosigmoid craniectomy (microvascular decompression [MVD] and internal neurolysis) and deep brain stimulation (DBS). Additionally, we correlate variability with residents' self-reported readiness for the surgical steps. The aim is to guide surgeons as they balance operative safety and efficiency with training obligations. METHODS: For each operation (retrosigmoid craniectomy and DBS), a standard workflow, segmenting the operation into components, was defined. We observed a representative sample of operations, timing the components, with a focus on variability. To assess perceptions of safety and risk among surgeons of various training levels, a survey was administered. Survey results were correlated with operative variability, attempting to identify areas for increasing value without compromising trainee experience. RESULTS: A sampling of each operation (n = 36) was observed during the study period. For MVD, craniectomy had the highest mean duration and standard deviation, whereas the MVD itself had the lowest mean duration and standard deviation. For DBS, the segments with largest standard deviation in duration were registration and electrode placement. For many steps of both procedures, there was a statistically significant relationship between increasing level of training and increasing perception of safety. CONCLUSION: This proof-of-concept study introduces an educational and process-improvement tool that can be used to aid surgeons in increasing the efficiency of patient care.

Distal Ventriculoatrial Shunt Revision in Adult Myelomeningocele Patient Performed via Endovascular Transvenous Approach.

BACKGROUND: Myelomeningocele patients with shunt-dependent hydrocephalus often require multiple shunt revisions, eventually exhausting first-line distal diversion sites. Ventriculoatrial (VA) shunts are used less commonly than ventriculoperitoneal shunts, but knowledge of their use and complications is important to the neurosurgeon's armamentarium. VA shunts differ from ventriculoperitoneal and ventriculopleural shunts in that the ideal distal catheter target is an anatomically small area in comparison with the peritoneal and pleural cavities. CASE DESCRIPTION: Here we present a case of an adult myelomeningocele patient who experienced migration of a distal VA shunt catheter. A minimally invasive revision technique that does not require recannulation of the vessels or open manipulation of the shunt is presented. CONCLUSIONS: This is the fourth reported instance of successful distal revision of a migrated VA shunt catheter via transfemoral endovascular snaring. Knowledge of the opportunities afforded by this technique and collaboration with thoracic surgery colleagues is of benefit to all neurosurgeons.

Blood Ethanol Levels Are Not Related to Coagulation Changes, as Measured by Thromboelastography, in Traumatic Brain Injury Patients.

BACKGROUND: Brain injury is a leading cause of death and disability in trauma patients. Ethanol (EtOH) use near the time of injury may contribute to worse outcomes in these patients by exacerbating coagulopathy. There are limited data regarding the effects of EtOH on coagulation and progression of traumatic intracranial hemorrhage (TICH). METHODS: We performed a retrospective analysis of a prospective observational study of 168 trauma patients with TBI at an urban level 1 trauma center. Thromboelastography (TEG) was performed on admission and over the subsequent 48 hours. Demographic, physiologic, and outcomes data were collected. Computed tomography imaging of the head performed within the first 48 hours of admission was analyzed for progression of TICH. RESULTS: Thirty-six percent of patients (n = 61) had positive blood EtOH on admission (median EtOH level = 198 mg/dL [range, 16-376 mg/dL]). EtOH-positive patients were less severely injured than EtOH-negative patients (P = 0.01). Other admission demographic and physiologic variables were similar between groups. There were no significant differences in TEG values between EtOH-positive and EtOH-negative patients on admission or during the subsequent 48 hours. There were no differences in radiographic progression of hemorrhage, the need for neurosurgical procedure, or mortality between EtOH-positive and EtOH-negative patients. CONCLUSIONS: EtOH use near the time of traumatic injury was not associated with alterations in coagulation, as measured by traditional coagulation tests or by TEG, in patients with TICH. Furthermore, a positive blood alcohol at admission was not associated with increased mortality or need for neurosurgical procedure these patients.

Moderate elevations in international normalized ratio should not lead to delays in neurosurgical intervention in patients with traumatic brain injury.

BACKGROUND: The management of severe traumatic brain injury (TBI) frequently involves invasive intracranial monitoring or cranial surgery. In our institution, intracranial procedures are often deferred until an international normalized ratio (INR) of less than 1.4 is achieved. There is no evidence that a moderately elevated INR is associated with increased risk of bleeding in patients undergoing neurosurgical intervention (NI). Thrombelastography (TEG) provides a functional assessment of clotting and has been shown to better predict clinically relevant coagulopathy compared with INR. We hypothesized that in patients with TBI, an elevated INR would result in increased time to NI and would not be associated with coagulation abnormalities based on TEG. METHODS: A secondary analysis of prospectively collected data was performed in trauma patients with intracranial hemorrhage that underwent NI (defined as cranial surgery or intracranial pressure monitoring) within 24 hours of arrival. Time from admission to NI was recorded. TEG and routine coagulation assays were obtained at admission. Patients were considered hypocoagulable based on INR if their admission INR was greater than 1.4 (high INR). Manufacturer-specified values were used to determine hypocoagulability for each TEG variable. RESULTS: Sixty-one patients (median head Abbreviated Injury Scale [AIS] score, 5) met entry criteria, of whom 16% had high INR. Demographic, physiologic, and injury scoring data were similar between groups. The median time to NI was longer in patients with high INR (358 minutes vs. 184 minutes, p = 0.027). High-INR patients were transfused more plasma than patients with an INR of 1.4 or less (2 U vs. 0 U, p = 0.01). There was no association between an elevated INR and hypocoagulability based on TEG. CONCLUSION: TBI patients with an admission INR of greater than 1.4 had a longer time to NI. The use of plasma transfusion to decrease the INR may have contributed to this delay. A moderately elevated INR was not associated with coagulation abnormalities based on TEG. Routine plasma transfusion to correct a moderately elevated INR before NI should be reexamined. LEVEL OF EVIDENCE: Diagnostic study, level III.

Late occurrence of drop metastasis to the spine in a case of esthesioneuroblastoma.

Esthesioneuroblastoma is an aggressive neuroectodermal tumor that originates from the olfactory mucosa and often recurs locally. Distant metastasis of esthesioneuroblastoma has been described, but there are few reports of drop metastasis to the spinal cord. Here, we report a case of multiple drop metastases to the cervical, thoracic, and lumbar regions of the spinal cord that occurred 18 years after resection and radiotherapy of the original anterior cranial fossa lesion. There was no evidence of local recurrence. The symptomatic lesion was treated with resection and adjuvant chemotherapy. The options available for treatment of this disease are summarized with a review of the few reported cases of spinal metastasis of esthesioneuroblastoma.

Expression of nestin by neural cells in the adult rat and human brain.

Neurons and glial cells in the developing brain arise from neural progenitor cells (NPCs). Nestin, an intermediate filament protein, is thought to be expressed exclusively by NPCs in the normal brain, and is replaced by the expression of proteins specific for neurons or glia in differentiated cells. Nestin expressing NPCs are found in the adult brain in the subventricular zone (SVZ) of the lateral ventricle and the subgranular zone (SGZ) of the dentate gyrus. While significant attention has been paid to studying NPCs in the SVZ and SGZ in the adult brain, relatively little attention has been paid to determining whether nestin-expressing neural cells (NECs) exist outside of the SVZ and SGZ. We therefore stained sections immunocytochemically from the adult rat and human brain for NECs, observed four distinct classes of these cells, and present here the first comprehensive report on these cells. Class I cells are among the smallest neural cells in the brain and are widely distributed. Class II cells are located in the walls of the aqueduct and third ventricle. Class IV cells are found throughout the forebrain and typically reside immediately adjacent to a neuron. Class III cells are observed only in the basal forebrain and closely related areas such as the hippocampus and corpus striatum. Class III cells resemble neurons structurally and co-express markers associated exclusively with neurons. Cell proliferation experiments demonstrate that Class III cells are not recently born. Instead, these cells appear to be mature neurons in the adult brain that express nestin. Neurons that express nestin are not supposed to exist in the brain at any stage of development. That these unique neurons are found only in brain regions involved in higher order cognitive function suggests that they may be remodeling their cytoskeleton in supporting the neural plasticity required for these functions.