Sergey Neckrysh

Virtual reality in neurosurgical education: Part-task ventriculostomy simulation with dynamic visual and haptic feedback

OBJECTIVE Mastery of the neurosurgical skill set involves many hours of supervised intraoperative training. Convergence of political, economic, and social forces has limited neurosurgical resident operative exposure. There is need to develop realistic neurosurgical simulations that reproduce the operative experience, unrestricted by time and patient safety constraints. Computer-based, virtual reality platforms offer just such a possibility. The combination of virtual reality with dynamic, three-dimensional stereoscopic visualization, and haptic feedback technologies makes realistic procedural simulation possible. Most neurosurgical procedures can be conceptualized and segmented into critical task components, which can be simulated independently or in conjunction with other modules to recreate the experience of a complex neurosurgical procedure. METHODS We use the ImmersiveTouch (ImmersiveTouch, Inc., Chicago, IL) virtual reality platform, developed at the University of Illinois at Chicago, to simulate the task of ventriculostomy catheter placement as a proof-of-concept. Computed tomographic data are used to create a virtual anatomic volume. RESULTS Haptic feedback offers simulated resistance and relaxation with passage of a virtual three-dimensional ventriculostomy catheter through the brain parenchyma into the ventricle. A dynamic three-dimensional graphical interface renders changing visual perspective as the users head moves. The simulation platform was found to have realistic visual, tactile, and handling characteristics, as assessed by neurosurgical faculty, residents, and medical students. CONCLUSION We have developed a realistic, haptics-based virtual reality simulator for neurosurgical education. Our first module recreates a critical component of the ventriculostomy placement task. This approach to task simulation can be assembled in a modular manner to reproduce entire neurosurgical procedures.

Ethylene oxide gas sterilization: a simple technique for storing explanted skull bone. Technical note.

The authors evaluated the effectiveness of a simple technique using ethylene oxide (EtO) gas sterilization and room temperature storage of autologous bone grafts for reconstructive cranioplasty following decompressive craniectomy. The authors retrospectively analyzed data in 103 consecutive patients who underwent cranioplasty following decompressive craniectomy for any cause at the University of Illinois at Chicago between 1999 and 2005. Patients with a pre-existing intracranial infection prior to craniectomy or lost to follow-up before reconstruction were excluded. Autologous bone grafts were cleansed of soft tissue, hermetically sealed in sterilization pouches for EtO gas sterilization, and stored at room temperature until reconstructive cranioplasty was performed. Cranioplasties were performed an average of 4 months after decompressive craniectomy, and the follow-up after reconstruction averaged 14 months. Excellent aesthetic and functional results after single-stage reconstruction were achieved in 95 patients (92.2%) as confirmed on computed tomography. An infection of the bone flap occurred in eight patients (7.8%), and the skull defects were eventually reconstructed using polymethylmethacrylate with satisfactory results. The mean preservation interval was 3.8 months in patients with uninfected flaps and 6.4 months in those with infected flaps (p = 0.02). A preservation time beyond 10 months was associated with a significantly increased risk of flap infection postcranioplasty (odds ratio [OR] 10.8, p = 0.02). Additionally, patients who had undergone multiple craniotomies demonstrated a trend toward increased infection rates (OR 3.0, p = 0.13). Data in this analysis support the effectiveness of this method, which can be performed at any institution that provides EtO gas sterilization services. The findings also suggest that bone flaps preserved beyond 10 months using this technique should be discarded or resterilized prior to reconstruction.

Anterior Approach for Complex Cervical Spondylotic Myelopathy

Cervical spondylotic myelopathy (CSM) is a slowly progressive disease resulting from age-related degenerative changes in the spine that can lead to spinal cord dysfunction and significant functional disability. The degenerative changes and abnormal motion lead to vertebral body subluxation, osteophyte formation, ligamentum flavum hypertrophy, and spinal canal narrowing. Repetitive movement during normal cervical motion may result in microtrauma to the spinal cord. Disease extent and location dictate the choice of surgical approach. Anterior spinal decompression and instrumented fusion is successful in preventing CSM progression and has been shown to result in functional improvement in most patients.

Comparison of perioperative complications following staged versus one-day anterior and posterior cervical decompression and fusion crossing the cervico-thoracic junction

INTRODUCTION Multilevel cervical pathology may be treated via combined anterior cervical decompression and fusion (ACDF) followed by posterior spinal instrumented fusion (PSIF) crossing the cervico-thoracic junction. The purpose of the study was to compare perioperative complication rates following staged versus same day ACDF combined with PSIF crossing the cervico-thoracic junction. MATERIAL AND METHODS A retrospective review of consecutive patients undergoing ACDF followed by PSIF crossing the cervico-thoracic junction at a single institution was performed. Patients underwent either same day (group A) or staged with one week interval surgeries (group B). The minimum follow-up was 12 months. RESULTS Thirty-five patients (14 females and 21 males) were analyzed. The average age was 60 years (37-82 years). There were 12 patients in group A and 23 in group B. Twenty-eight complications noted in 14 patients (40%) included: dysphagia in 13 (37%), dysphonia in 6 (17%), post-operative reintubation in 4 (11%), vocal cords paralysis, delirium, superficial incisional infection and cerebrospinal fluid leakage each in one case. Significant differences comparing group A vs. B were found in: the number of levels fused posteriorly (5 vs. 7; p=0.002), total amount of intravenous fluids (3233ml vs. 4683ml; p=0.03), length of hospital stay (10 vs. 18 days; p=0.03) and transfusion of blood products (0 vs. 9 patients). Smoking and cervical myelopathy were the most important risk factors for perioperative complications regardless of the group. CONCLUSIONS Staging anterior cervical decompression and fusion with posterior cervical instrumented fusion 1 week apart does not decrease the incidence of perioperative complications.

CT Ventriculography for diagnosis of occult ventricular cysticerci

Background: Neurocysticercosis is the most common parasitic infection of the central nervous system (CNS). Intraventricular lesions are seen in 7–20% of CNS cysticercosis. Intraventricular lesions can be missed by computed tomography (CT) and magnetic resonance imaging (MRI) as they are typically isodense/isointense to the cerebrospinal fluid. We present our experience with CT ventriculography to visualize occult cysts. Case Description: Two patients presented with hydrocephalus and suspected neurocysticercosis were evaluated with CT and MRI with and without contrast failing to reveal intraventricular lesions. CT-ventriculography was used: 10 ml of cerebrospinal fluid was drained from the ventriculostomy catheter, and 10 ml of iohexol 240 diluted 1:1 with preservative-free saline was injected through the ventriculostomy catheter. Immediate CT of the brain was performed. The first patient had multiple cysts located throughout the body of the left lateral ventricle. The second patient had a single lesion located in the body of the lateral ventricle. The CT-ventriculography findings helped in identifying the lesions and plan the surgical intervention that was performed with the aid of an endoscope to remove the cysts. Conclusions: Intraventricular neurocysticercosis is a common parasitic disease which can be difficult to diagnose. We used CT-ventriculography with injection of contrast through the ventriculostomy catheter in two patients where CT and MRI failed to demonstrate the lesions. This technique is a safe and useful tool in the imaging armamentarium when intraventricular cystic lesions are suspected.

Primitive neuroectodermal tumor after radiation therapy for craniopharyngioma.

The authors report a case of primitive neuroectodermal tumor induced by radiation therapy of craniopharyngioma. This African-American male patient originally presented with craniopharyngioma, for which he underwent resection and whole-brain radiation therapy. Eight years later, at the age of 20 years, he returned with a left facial droop and left hemiparesis. A right basal ganglia mass was identified and resected. Histopathological examination identified the lesion as primitive neuroectodermal tumor. Although radiation therapy has shown to be beneficial in decreasing the recurrence rate in subtotally resected craniopharyngioma, the risks of radiation treatment should be clearly communicated to the patients, their families, and neurosurgeons before starting such treatment. This report expands the spectrum of reported radiation-induced neoplasms in the CNS.

Axial and oblique C2 pedicle diameters and feasibility of C2 pedicle screw placement: Technical note

Background: For C2 pedicle screw placement/instrumentation, it is critical to adequately measure the axial and oblique C2 pedicle diameters utilizing the intraoperative O-arm. Methods: Thirty-three patients who underwent C2 pedicle screw placement (2013–2016) utilizing the O-arm with tri-planar reconstruction. As O-arm software does not allow calibrated measurements with the applications measurement tool, we directly measured axial and oblique widths of the C2 pedicles on the screen with a regular ruler (e.g., “screen width of C2 pedicle”). Results: The axial width of the C2 pedicles ranged from 6 to 15 mm on the right (mean 10.44 ± 2.15 mm) to 7 to 14 mm (10.29 ± 1.72 mm) on the left. The oblique width of C2 pedicles ranged from 10 to 19 mm on the right (mean, 14.73 ± 1.85 mm) and from 12 to 19 mm on the left (mean, of 15.33 ± 1.67 mm). These measurements indicated that oblique screen widths of the C2 pedicles were 1.4 and 1.5 times higher than their axial screen widths on the right and left sides, respectively. Conclusions: The oblique screen widths of the C2 pedicles better predict the feasibility of C2 pedicle screw placement vs. their axial screen width as measured with a regular ruler.

T-1 pedicle subtraction osteotomy for the treatment of rigid cervical kyphotic deformity: report of 4 cases

Cervical kyphotic deformity represents a difficult to treat pathology often arising from multiple factors including, but not limited to, traumatic injuries, degenerative changes, and ankylosing spondylitis. Furthermore, treatment of these deformities becomes increasingly difficult with any preexisting instrumentation. Currently, several options exist to treat these severe deformities, with the Smith-Petersen osteotomy and C-7 pedicle subtraction osteotomy being the most frequently used approaches. However, these techniques come with significant risk to the patient including nerve root injury as well as compression of the vertebral arteries. The authors here report on a series of 4 patients with rigid cervical deformity who underwent T-1 pedicle subtraction osteotomy. The authors review the relevant literature and provide a novel, less risky, and potentially more corrective approach for treating cervical deformities.

Spinal epidural abscess in a patient with piriformis pyomyositis

Background: Spinal epidural abscess resulting from piriformis pyomyositis is extremely rare. Such condition can result in serious morbidity and mortality if not addressed in a timely manner. Case Description: The authors describe the case of a 19-year-old male presenting with a 2-week history of fever, low back pain, and nuchal rigidity. When found to have radiographic evidence of a right piriformis pyomyositis, he was transferred to our institution for further evaluation. Because he demonstrated rapid deterioration, cervical, thoracic, and lumbar magnetic resonance imaging scans were emergently performed. They revealed an extensive posterior spinal epidural abscess causing symptomatic spinal cord compression extending from C2 to the sacrum. He underwent emergent decompression and abscess evacuation through a dorsal midline approach. Postoperatively, he markedly improved. Upon discharge, the patient regained 5/5 strength in both upper and lower extremities. Cultures from the epidural abscess grew methicillin-sensitive Staphylococcus aureus warranting a 6-week course of intravenous nafcillin. Conclusion: A 19-year-old male presented with a holospinal epidural abscess (C2 to sacrum) originating from piriformis pyomyositis. The multilevel cord abscess was emergently decompressed, leading to a marked restoration of neurological function.

Anterior cervical corpectomy and fusion for blastomycosis causing destruction of C6 vertebra: a case report.

IntroductionWe describe a patient who had cervical spine osteomyelitis caused by Blastomyces dermatitidis that resulted in cord compression and cervical spine instability.Case presentationA 25-year-old Hispanic woman presented with fever, sweats, neck pain, and an enlarging neck mass with purulent discharge after sustaining a C6 vertebral body fracture. Magnetic resonance imaging confirmed C6 vertebral osteomyelitis, demonstrated by vertebral body destruction, cervical spine instability, prevertebral abscess, and spinal cord compression. She underwent C6 anterior cervical corpectomy and fusion, with fungal cultures confirming Blastomyces dermatitidis.ConclusionsAnterior cervical corpectomy and fusion successful debrided, decompressed, and restored cervical spine stability in a patient with vertebral osteomyelitis caused by Blastomyces dermatitidis. The patient was subsequently treated with a 1-year course of itraconazole and had no recurrence of infection 4 years postoperatively.