Robotic-Guided Stereoelectroencephalography for Refractory Epilepsy: Technique and Nuances.

BACKGROUND: Stereoelectroencephalography (SEEG) has become an integral part of epilepsy surgery, often used in the localization of the epileptogenic zone. It is an essential modality not only in the evaluation of nonlesional but also lesional drug refractory epilepsy, especially in the presence of anatomo-electro-clinical discordance. OBJECTIVE: To describe our technique and the operative nuances involved in the performance of robotic SEEG placement. METHODS: A 28-year lady with seizure onset at the age of 15 years presented with two types of seizures: one was associated with an aura of chest discomfort, palpitations along with oral and bilateral automatisms. There was associated speech and behavioral arrest along with ictal urinary incontinence. The other type has head turning to the right with secondary generalization lasting up to 1 min. RESULTS: Multimodality investigations showed bilateral temporal origin of seizures. SEEG evaluation revealed left amygdala and anterior temporal neocortical (ATL) origin of seizures. The patient underwent left ATL and amygdalectomy. Histopathology revealed focal cortical dysplasia (FCD type Ib). The patient became seizure free (ILAE Class 1) at 1-year follow up. CONCLUSION: Robotic-guided SEEG is a safe and accurate method of evaluating complex MRI negative epilepsy.

Management of Myelopathy due to Anterior Soft-Tissue Compression in Vertebral Hemangioma.

OBJECTIVE: Vertebral hemangiomas are benign but highly vascular lesions and are one of the most common lesions of the vertebral column. Anterior soft-tissue compression of spinal cord due to vertebral body hemangioma is challenging to manage. Our objective was to assess long-term clinical and radiologic effects of direct transpedicular absolute alcohol embolization, laminectomy, and short-segment instrumented fusion on resolution of extraosseous epidural soft tissue and improvement in myelopathy in cases of vertebral hemangioma causing anterior soft-tissue compression. MATERIALS AND METHODS: This was a retrospective analysis that included patients with single-level vertebral hemangioma with anterior intraspinal soft-tissue growth causing spinal cord compression and clinical features of myelopathy between June 2007 and June 2019 at authors' institute. Transpedicular vertebral body injection of absolute alcohol, laminectomy, and pedicle screw rod instrumentation was performed in all patients. Clinicoradiologic outcomes of surgery were noted. We proposed a grading system for the extent of anterior extraosseous epidural soft-tissue compression. RESULTS: In total, 14 patients were included in study. Their mean age was 28.4 ± 14.4 years. Mean follow-up duration was 67.5 ± 36.2 months. All patients had preoperative radiologic grade 4 compression. Postoperative radiologic grading improved to grade 1 in 4 (28.6%), grade 2 in 8 (57.1%), and grade 3 in 2 (14.3%). All the patients improved neurologically after surgery. Eleven patients improved to American Spinal Injury Association (ASIA) grade E, 2 improved to ASIA D, and 1 improved to ASIA C at the last follow-up visit. CONCLUSIONS: Vertebral hemangiomas with anterior extraosseous epidural extension causing spinal canal compromise and myelopathy can be managed with direct transpedicular ethanol embolization, laminectomy, and short-segment instrumented fusion with resolution of the extraosseous soft tissue and improvement in myelopathy. The procedure is relatively simple, cost effective, and has a good outcome.

Transpedicular Approach for Corpectomy and Circumferential Arthrodesis in Traumatic Lumbar Vertebral Body Burst Fractures: A Retrospective Analysis of Outcome in 35 Patients.

BACKGROUND: Traumatic vertebral burst fractures can be surgically approached via different approaches (anterior/posterior, or combined). Transpedicular approach (TA) is a posterior approach that has the advantage of achieving circumferential arthrodesis via single posterior only approach. The purpose of this study was to analyze our experience with TA in management of traumatic lumbar burst fractures (TLBFs). MATERIALS AND METHODS: All consecutive patients with TLBFs managed with TA over 5 years duration were included in this retrospective study. Correction of kyphotic deformity and change in neurological status were analyzed to assess outcome. Cobb's angle and ASIA grade were used for this purpose. RESULTS: There were 21 males and 14 females. Eight patients had complete (ASIA-A) while 22 had incomplete injury. All patients had a TLICS score >=4. The mean preoperative Cobb's angle was 13.97° that improved to -3.57° postoperatively (mean kyphosis correction-17.54°). None of the patients developed iatrogenic nerve root injury. There was no perioperative mortality. The mean cobb's angle was 1.23° at 39.1 months follow-up. Eight patients developed cage subsidence but none required revision surgery. Postoperatively, 27 (77.1%) patients showed neurological improvement and none deteriorated. The median ASIA score improved from 3 to 5. A fusion rate of 91.4% was observed at last follow-up. CONCLUSIONS: The advantages of TA including sense of familiarity with posterior approach amongst spine surgeons, lesser approach-related morbidity, and results comparable to anterior/combined approaches, make TA an attractive option for managing TLBFs. Although technically difficult, it can be successfully used for circumferential arthrodesis in lumbar region without sacrificing nerve roots.

Robot-guided Ventriculoperitoneal Shunt in Slit-like Ventricles.

BACKGROUND: Ventriculoperitoneal shunt (VPS) is the most common procedure used in the management of hydrocephalus regardless of the etiology. The standard free-hand technique is used for the placement of VPS in patients with enlarged ventricles. In patients with very small ventricles, CSF access through ventriculostomy becomes challenging and free-hand technique may be associated with high failure rates. In these situations, stereotactic-guided VPS becomes very useful. OBJECTIVE: To validate and describe the technique of robotic-guided VPS in cases with very small ventricles. METHODS: Three patients underwent VPS with robotic guidance between 2016 and 2019. One patient with a diagnosis of occipital meningocele, who later developed recalcitrant CSF leak from the operative site, and two other patients were diagnosed with idiopathic intracranial hypertension (IIH). Plain CT brain with 1-mm slice thickness acquired prior to the surgery was uploaded into the ROSA machine (Zimmer Biomet Warsaw, Indiana). The trajectory for the VPS is created on the robotic software presurgery. The patient is placed in the supine position with head turned to the side contralateral to VPS insertion and fixed with Mayfield clamp. Registration of the patient is done with the robot. The placement of the VPS is commenced with the robotic arm in the predetermined trajectory. RESULTS: Ventricle was hit in a single attempt in all the cases. CSF leak stopped in the case with meningocele; headache, and visual acuity improved in both the cases of IIH. CONCLUSION: Robotic-guidance provides a safe and accurate method of VPS placement even in the presence of slit-like ventricles.

Evolution to Pedicle Reformation Technique in Surgical Management of Hangman's Fracture.

BACKGROUND: Opinions vary regarding optimal treatment of unstable hangman's fractures. Recent technological advances have allowed short segment, motion preserving fixation, even in complex cases. The aim of the study was to demonstrate C1-C2 motion-preserving short-segment fusion in hangman's fracture and the evolution of technique from pedicle realignment to pedicle reformation in complex fractures with resorbed/destroyed C2 pedicles. METHODS: This was a retrospective study. Patients operated by a single surgeon at a tertiary level center from 2012 to 2018 were included. The type of fracture, operating time, and blood loss was recorded. Neurologic deficits were recorded using the American Spinal Injury Association scale with regular clinicoradiologic follow-up. RESULTS: Nine patients (8 male), with a mean age of 36 ± 16.9 years were included. In the initial 7 patients, C2 pedicle screw, C3-C4 lateral mass screw, and rod fixation was done. The last 2 patients were complex neglected injuries, with 1 having severe angulation and displacement and the other having spondyloptosis with C2 body placed anterior to C4 body. In both these patients, direct C2 body screw were placed and pedicle reconstruction was done. Mean follow up was 41.4 ± 29.8 months. All 5 patients with preoperative neurologic deficits had improvement in power. C1-C2 joint motion was preserved in all. All patients had bony fusion. CONCLUSIONS: Preservation of motion at the C1-C2 joint should be the goal in all surgically managed hangman's fracture patients. The technique of C2 pedicle reconstruction can be utilized for the same in old neglected hangman's fractures.

Dorsal Root Entry Zone (DREZ) Lesioning for Brachial Neuralgia.

BACKGROUND AND INTRODUCTION: Patients with brachial plexus avulsion (BPA) injuries often suffer from chronic disabling drug refractory neuropathic pain. Dorsal root entry zone (DREZ) lesioning is currently the most effective surgical procedure for this intractable brachial neuralgia following BPA. OBJECTIVE: To demonstrate a novel technique of "Micro-scissor DREZotomy" developed at our institution. PROCEDURE: A 55-year-old gentleman underwent right cervical microscissor DREZotomy for post BPA neuralgia. Exclusive use of microscissors along the posterolateral sulcus, causing mechanical disruption of the nociceptive pathways through sharp dissection, results in precise lesioning with excellent pain free outcomes. RESULTS: The patient had complete relief of the pain and uneventful recovery following the surgery and remains to be pain free at 1 year follow up. CONCLUSION: Microscissor DREZotomy is a simple cost-effective technique. It can easily be performed in the peripheral centers with limited resources and is a safe and effective technique in experienced hands.

Management of C2 Body Giant Cell Tumor by Innovatively Fashioned Iliac Crest Graft and Modified Cervical Mesh Cage Used as Plate.

BACKGROUND: Locally aggressive vertebral body tumors of the axis must be treated with wide local excision for best outcome. Reconstruction of the load-bearing vertebra needs to be done after tumor resection in such a manner so as to give stable, long-term fusion in this young population. METHODS: We describe the management strategy of a 25-year-old acutely quadriplegic patient, with respiratory distress, with a C2 giant cell tumor. The use of a novel iliac crest graft modification used for C2 reconstruction along with a modified mesh cage used as an anterior plate has been reported. RESULTS: The patient had a good outcome at 18 months' follow-up, with neurologic improvement and a solid fusion. CONCLUSIONS: Iliac crest autograft is inexpensive and easy to harvest and can be considered as a C2 prosthesis, especially in a resource-constrained setting. Modified iliac crest graft can be used for load transmission from C1 lateral mass to C3 body, and the mesh cage can be modified according to need as a plate with good results in an emergency.

Traumatic Atlantoaxial Spondyloptosis Associated with Displaced Odontoid Fracture: Complete Reduction via Posterior Approach Using "Joint Remodeling" Technique.

BACKGROUND: Atlantoaxial spondyloptosis (AAS), which is defined as complete displacement of facets of atlas anterior to the facets of axis such that there is no contact between the 2 articulating surfaces, is an extremely rare manifestation of atlantoaxial instability. The reason for an extreme rarity of traumatic AAS is probably the severity of injury in traumatic AAS that is usually incompatible to life. It represents the most severe form of atlantoaxial dislocation, and complete reduction in such a case presents a real technical challenge because of the interlocking of C1-C2 facets. Cranial traction fails to achieve reduction in such cases. CASE DESCRIPTION: In this report, we describe a case of traumatic odontoid fracture associated with AAS and discuss our technique of complete reduction of deformity via posterior approach. An 11-year-old child presented to us 4 months after a road traffic accident with progressive spastic quadriparesis. On evaluation, displaced type II odontoid fracture with AAS was detected. The patient underwent surgery via posterior approach. The techniques of "joint manipulation" and "joint remodeling" were used to achieve complete reduction of spondyloptosis. Postoperative imaging showed complete reduction of deformity. The patient also improved neurologically after surgery. CONCLUSION: This case report aims to present the ability of "joint manipulation" and "joint remodeling" techniques in achieving excellent reduction in even one of the most difficult post-traumatic deformities that affect the craniovertebral junction.

Giant Bicompartmental Cystic Tentorial Schwannoma Mimicking a Meningioma.

BACKGROUND: Intracranial schwannomas most commonly arise from the vestibulocochlear nerve and less frequently from trigeminal, facial, and hypoglossal nerves. Intracranial schwannomas unrelated to cranial nerves are very rare; only approximately 50 cases have been reported in the literature. Tentorial schwannoma (TS) is even rarer, with only 13 cases reported to date. We present a rare case of giant TS. CASE DESCRIPTION: A 21-year-old man presented with generalized headache and dizziness for the past 6 months and worsening of symptoms for the past 2 months. On evaluation, he was found to have a cystic lesion arising from the right tentorium with multiple internal septa and fluid levels, with both supratentorial and infratentorial extension. The presence of a dural tail sign and tentorial origin led us to make a preoperative diagnosis of tentorial meningioma. The patient underwent complete excision, and a diagnosis of TS was made based on histopathologic analysis. CONCLUSIONS: TSs are extremely rare. Knowledge of radiologic and morphologic features can be helpful in making a preoperative diagnosis. The dural tail sign, which is considered a characteristic feature of meningioma, is commonly seen in TS as well, and thus TS should always be considered in the differential diagnosis of lesions arising from the tentorium.

Comparison of Autonomic Function before and after Surgical Intervention in Patients with Temporal Lobe Epilepsy.

BACKGROUND AND PURPOSE: Refractory temporal lobe epilepsy (TLE) is commonly associated with imbalances in cardiovascular (CV) parasympathetic and sympathetic functions, which are treated using TLE surgery. We investigated the effect of hemispheric lateralization of seizure foci on autonomic CV functions before and after TLE surgery. METHODS: The study was conducted on patients with left TLE (LTLE, n = 23) and right TLE (RTLE, n = 30) undergoing unilateral TLE surgery. To assess the autonomic CV functions, changes in the heart rate (ΔHR) and blood pressure (BP) were measured using a standardized battery of autonomic reactivity tests before surgery and at 3 and 6 months after surgery. RESULTS: Before surgery, ΔHR and the expiration to inspiration ratio (E:I) during the deep breathing test were higher in the LTLE group than in the RTLE group (both p < 0.001), but both outcomes were comparable between the groups at 3 and 6 months. ΔHR decreased at 3 and 6 months (p < 0.001 and 0.01, respectively) compared with preoperative values. The E:I at 3 months in the LTLE group was lower (p = 0.04) than the preoperative values. Decrease in systolic BP during the head-up tilt test was greater in the LTLE group than in the RTLE group (p = 0.002) before surgery. The maximum increase in diastolic BP during the cold pressor test was lower in the RTLE group at 6 months than that before surgery (p = 0.001) and in the LTLE group (p = 0.002). CONCLUSIONS: We found that hemispheric lateralization of seizure foci in the temporal lobe had a differential effect on autonomic CV functions before surgery. Before surgery, parasympathetic reactivity was higher in the LTLE group, and sympathetic reactivity was higher in the RTLE group. After surgery, autonomic CV functions were comparable between the groups, suggesting that TLE surgery stabilizes autonomic CV functions.

FDG-PET/MRI coregistration and diffusion-tensor imaging distinguish epileptogenic tubers and cortex in patients with tuberous sclerosis complex: a preliminary report.

PURPOSE: Patients with tuberous sclerosis complex (TSC) are potential surgical candidates if the epileptogenic region(s) can be accurately identified. This retrospective study determined whether FDG-PET/MRI coregistration and diffusion-tensor imaging (DTI) showed better accuracy in the localization of epileptogenic cortex than structural MRI in TSC patients. METHODS: FDG-PET/MRI coregistration and/or DTI for apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were utilized in 15 TSC patients. Presurgery scalp EEG and postsurgery seizure control identified epileptogenic tubers (n = 27) and these were compared with nonepileptogenic tubers (n = 204) for MRI tuber volume, volume of FDG-PET hypometabolism on MRI coregistration, DTI, ADC, and FA values. RESULTS: Compared with nonepileptogenic tubers, epileptogenic regions had increased volume of FDG-PET hypometabolism (p < 0.0001), and increased ADC values in subtuber white matter (p < 0.0001). In contrast, the largest MRI identified tuber (p = 0.046) and decreased FA values (p = 0.58) were less accurate in identifying epileptogenic regions. Larger volumes of FDG-PET hypometabolism correlated positively with increased ADC values (p = 0.029), and localized to areas of cortical dysplasia adjacent to the tuber in four cases. CONCLUSIONS: Larger volumes of FDG-PET hypometabolism relative to MRI tuber size and higher ADC values identified epileptogenic tubers and adjoining cortex containing cortical dysplasia in TSC patients with improved accuracy compared with largest tuber by MRI or lowest FA values. Used in conjunction with ictal scalp EEG and interictal magnetoencephalography, these newer neuroimaging techniques should improve the noninvasive evaluation of TSC patients with intractable epilepsy in distinguishing epileptogenic sites for surgical resection.