Jeremy C. Peterson

A case series of dural venous sinus stenting in idiopathic intracranial hypertension: association of outcomes with optical coherence tomography.

Purpose/Aim: Pseudotumor cerebri or idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure of unknown etiology. A subset of patients has shown benefit from endovascular dural venous sinus stenting (DVSS). We sought to identify a population of IIH patients who underwent DVSS to assess outcomes. Materials and Methods: A retrospective study was performed to identify IIH patients with dural sinus stenosis treated with DVSS. Outcome measures included dural sinus pressure gradients, peripapillary retinal nerve fiber layer (RNFL) thickness using optical coherence tomography and improvement in symptoms. Results: Seventeen patients underwent DVSS. Average pre- and post-intervention pressure gradients were 23.06 and 1.18 mmHg, respectively (p < 0.0001). Sixteen (94%) noted improvement in headache, fourteen (82%) had visual improvement and all (100%) patients had improved main symptom. Of 11 patients with optical coherence tomography, 8 showed decreased RNFL thickness and 3 remained stable; furthermore, these 11 patients had improved vision with improved papilledema in 8, lack of pre-existing papilledema in 2 and stable, mild edema in 1 patient. Conclusions: Our series of patients with dural sinus stenosis demonstrated improvement in vision and reduction in RNFL thickness. DVSS appears to be a useful treatment for IIH patients with dural sinus stenosis.

Individualized Surgical Approach Planning for Petroclival Tumors Using a 3D Printer.

Objectives To determine the utility of three-dimensional (3D) printed models in individualized petroclival tumor resection planning by measuring the fidelity of printed anatomical structures and comparing tumor exposure afforded by different approaches. Design Case series and review of the literature. Setting Tertiary care center. Participants Three patients with petroclival lesions. Main Outcome Measures Subjective opinion of access by neuro-otologists and neurosurgeons as well as surface area of tumor exposure. Results Surgeons found the 3D models of each patients skull and tumor useful for preoperative planning. Limitations of individual surgical approaches not identified through preoperative imaging were apparent after 3D models were evaluated. Significant variability in exposure was noted between models for similar or identical approaches. A notable drawback is that our printing process did not replicate mastoid air cells. Conclusions We found that 3D modeling is useful for individualized preoperative planning for approaching petroclival tumors. Our printing techniques did produce authentic replicas of the tumors in relation to bony structures.

A 3D map of the hindlimb motor representation in the lumbar spinal cord in Sprague Dawley rats

OBJECTIVE Spinal cord injury (SCI) is a devastating neurological trauma with a prevalence of about 282 000 people living with an SCI in the United States in 2016. Advances in neuromodulatory devices hold promise for restoring function by incorporating the delivery of electrical current directly into the spinal cord grey matter via intraspinal microstimulation (ISMS). In such designs, detailed topographic maps of spinal cord outputs are needed to determine ISMS locations for eliciting hindlimb movements. The primary goal of the present study was to derive a topographic map of functional motor outputs in the lumbar spinal cord to hindlimb skeletal muscles as defined by ISMS in a rat model. APPROACH Experiments were carried out in nine healthy, adult, male, Sprague Dawley rats. After a laminectomy of the T13-L1 vertebrae and removal of the dura mater, a four-shank, 16-channel microelectrode array was inserted along a 3D (200 µm) stimulation grid. Trains of three biphasic current pulses were used to determine evoked movements and electromyographic (EMG) activity. Via fine wire EMG electrodes, stimulus-triggered averaging (StTA) was used on rectified EMG data to determine response latency. MAIN RESULTS Hindlimb movements were elicited at a median current intensity of 6 µA, and thresholds were significantly lower in ventrolateral sites. Movements typically consisted of whole leg, hip, knee, ankle, toe, and trunk movements. Hip movements dominated rostral to the T13 vertebral segment, knee movements were evoked at the T13-L1 vertebral junction, while ankle and digit movements were found near the rostral L1 vertebra. Whole leg movements spanned the entire rostrocaudal region explored, while trunk movements dominated medially. StTAs of EMG activity demonstrated a latency of ~4 ms. SIGNIFICANCE The derived motor map provides insight into the parameters needed for future neuromodulatory devices.

Misplaced cervical screws requiring reoperation

Study Design: A multicenter, retrospective case series. Objective: In the past several years, screw fixation of the cervical spine has become commonplace. For the most part, this is a safe, low-risk procedure. While rare, screw backout or misplaced screws can lead to morbidity and increased costs. We report our experiences with this uncommon complication. Methods: A multicenter, retrospective case series was undertaken at 23 institutions in the United States. Patients were included who underwent cervical spine surgery from January 1, 2005, to December 31, 2011, and had misplacement of screws requiring reoperation. Institutional review board approval was obtained at all participating institutions, and detailed records were sent to a central data center. Results: A total of 12 903 patients met the inclusion criteria and were analyzed. There were 11 instances of screw backout requiring reoperation, for an incidence of 0.085%. There were 7 posterior procedures. Importantly, there were no changes in the health-related quality-of-life metrics due to this complication. There were no new neurologic deficits; a patient most often presented with pain, and misplacement was diagnosed on plain X-ray or computed tomography scan. The most common location for screw backout was C6 (36%). Conclusions: This study represents the largest series to tabulate the incidence of misplacement of screws following cervical spine surgery, which led to revision procedures. The data suggest this is a rare event, despite the widespread use of cervical fixation. Patients suffering this complication can require revision, but do not usually suffer neurologic sequelae. These patients have increased cost of care. Meticulous technique and thorough knowledge of the relevant anatomy are the best means of preventing this complication.

Three-Dimensional Printed Model Used to Teach Skull Base Anatomy Through a Transsphenoidal Approach for Neurosurgery Residents

BACKGROUND: Skull base anatomy through a transsphenoidal approach is challenging for the neurosurgical resident to conquer. OBJECTIVE: To demonstrate that stereolithography, or 3-dimensional (3-D) printing, is a useful educational tool for neurosurgery residents to learn skull base anatomy. METHODS: Before any formal teaching, residents were brought into the operating room where they were asked to identify key structures seen through an endoscopic transsphenoidal approach. Scoring was based on correctly naming the anatomical structures. After the initial testing, all residents participated in a didactic lecture reviewing this anatomy by using 2-dimensional pictures. Residents were then divided into 2 groups: A and B. Group B residents were additionally taught through neurosurgical simulation using a 3-D printed model and an endoscope. Following all formal teaching, residents were retested in the operating room. RESULTS: A maximum score of 8 points was possible if all structures were identified correctly. Group A had mean scores of 2.75 on initial testing compared with 5 after the lecture (P = .041 using 2-tailed t test). Group B had mean scores of 2.75 on initial testing compared with 7.5 after the lecture and 3-D model simulation (P = .002). When comparing mean scores after formal teaching in groups A and B, 5 vs 7.5 were obtained for lecture only vs lecture and 3-D model simulation, respectively (P = .031). CONCLUSION: Three-dimensional models used in neurosurgical simulation to teach skull base anatomy through a transsphenoidal approach showed objective and subjective improvement in testing scores in neurosurgery residents. This study confirms that 3-D models are a useful educational tool.

Safety, Efficacy, and Cost-Analysis of Percutaneous Endoscopic Gastrostomy and Ventriculoperitoneal Shunt Placement in a Simultaneous Surgery

BACKGROUND Limited historical data suggest that concomitant placement of both a ventriculoperitoneal (VP) shunt and percutaneous endoscopic gastrostomy (PEG) tube is associated with an increased risk of complications, including VP shunt infections. Here we compare the outcomes and cost difference between 2 groups of patients, one in which a VP shunt and PEG tube were placed in the same operation and the other in which separate operations were performed. METHODS A total of 10 patients underwent simultaneous placement of a VP shunt and PEG tube. This group was compared with a group of 18 patients that underwent separate placements. Hospital billing charges were used to compare the total cost of the procedures in the 2 groups. RESULTS Eight of the 10 patients presented with aneurysmal subarachnoid hemorrhage. The average length of stay was 25 ± 2 days for the simultaneous procedure group and 43 ± 7 days for the separate procedures group. The average duration of follow-up was 12 ± 3 months after simultaneous placement. No patient in the simultaneous surgery group had signs of infection or shunt malfunction at last follow-up. The overall complication rate was significantly lower in the simultaneous surgery group. A cost analysis demonstrated significant cost savings by completing both procedures in the same surgical procedure. CONCLUSIONS Simultaneous placement of a PEG tube and VP shunt is safe, efficacious, and cost-effective. Thus, in patients requiring both a VP shunt and PEG tube, placement of both devices in a single surgical procedure should be considered.

3D Printed Models in Neurosurgical Training

Neurosurgical training has evolved over time. New technology has developed novel methods to supplement training. 3D printed models are an innovative method used to teach and train in various parts of neurosurgery. This chapter focuses on the variety of neurosurgical sub-specialties and how 3D printed models can be used. Cerebral aneurysms are a common pathology in neurosurgery that can be treated with surgical clipping of endovascular coiling. As endovascular technologies have advanced, resident exposure to clipping has diminished. The use of 3D models has supplemented this education. Tumor surgery in neurosurgery is challenging due to the various approaches and complex anatomy that must be mastered. 2D pictures are helpful, but converting this to three dimensions for surgery is difficult. The use of 3D models can really help with understanding anatomy. This is also helpful for transsphenoidal surgery and minor/bedside procedures. Spinal surgery can also be better understood with the use of 3D models. Various 3D models have been created to better understand the directions to place spinal instrumentation. As 3D printed models get more sophisticated, their use in neurosurgery as a training tool will grow. This chapter describes the various ways 3D printed models have impacted neurosurgical training.

Herniated gyrus rectus causing idiopathic compression of the optic chiasm

Anomalies in the frontal lobe can interfere with visual function by compression of the optic chiasm and nerve. The gyrus rectus is located at the anterior cranial fossa floor superior to the intracranial optic nerves and chiasm. Compression of these structures by the gyrus rectus is often caused by neoplastic or dysplastic growth in the area. We report a rare case of a herniated gyrus rectus impinged on the optic chiasm and nerve without a clear pathological cause for the herniation.

Poster 202 A Translational Model of Traumatic Brain Injury: Motor Recovery from a Focal Controlled Cortical Impact to Primary Motor Cortex

for possible paraneoplastic etiology of diffuse demyelinating polyneuropathy. Conclusions: Paraneoplastic diffuse demyelinating peripheral neuropathy is an uncommon cause of progressive weakness in the setting of malignancy and should be considered in the differential diagnosis of otherwise unexplained weakness in individuals with cancer. Acute inpatient rehabilitation can also help improve functional outcomes. Level of Evidence: Level V

High-failure Rate of ETV in Pineal Region Glioblastoma

Pineal region glioblastoma is a rare entity that presents a propensity for failure of endoscopic third ventriculostomy (ETV) when compared with other pineal region tumors. We present a case of pineal region glioblastoma multiforme that initially failed ETV and required subsequent shunting. In a review of the literature, this seems to be a characteristic of previously reported cases. Although ETV is commonly used to treat hydrocephalus related to a variety of pineal region tumors and is usually a very successful strategy, treating physicians should be aware that in the case of a pineal region glioblastoma multiforme there is a high failure rate of ETV and these cases are better managed by a ventriculoperitoneal shunt.