A Modified Lateral Orbitotomy Approach to the Superior Orbital Fissure: A Video Case Report and Review of Anatomy.

BACKGROUND: The lateral orbitotomy approach (LOA) is often used for accessing the orbital contents and middle skull base; however, most prior descriptions of the LOA involve complete drilling of the lateral orbital wall. This practice requires retraction of the orbital contents and produces postoperative diplopia that the patient experiences for a limited time. OBJECTIVE: To describe a modified LOA with partial sparing of the lateral orbital wall for accessing lesions of the superior orbital fissure (SOF). METHODS: One patient with a progressively enlarging SOF lesion and visual loss underwent a modified LOA for resection. The orbital rim lateral to the SOF was removed as a bone flap, and the greater wing of the sphenoid inferior to the SOF was drilled to expose the lesion. The lateral orbital wall was thinned but was not completely removed. The orbital rim was resecured with miniplates and screws. RESULTS: Gross total resection of the SOF mass was achieved without unnecessary exposure or retraction of the orbital contents. Histopathologic analysis of the resected mass was consistent with a cavernous hemangioma. The patient had a good cosmetic outcome without complication. CONCLUSION: Modified LOA with partial sparing of the lateral orbital wall is a feasible approach for lesions of the SOF.

Virtual Reality Tumor Resection: The Force Pyramid Approach.

BACKGROUND: The force pyramid is a novel visual representation allowing spatial delineation of instrument force application during surgical procedures. In this study, the force pyramid concept is employed to create and quantify dominant hand, nondominant hand, and bimanual force pyramids during resection of virtual reality brain tumors. OBJECTIVE: To address 4 questions: Do ergonomics and handedness influence force pyramid structure? What are the differences between dominant and nondominant force pyramids? What is the spatial distribution of forces applied in specific tumor quadrants? What differentiates "expert" and "novice" groups regarding their force pyramids? METHODS: Using a simulated aspirator in the dominant hand and a simulated sucker in the nondominant hand, 6 neurosurgeons and 14 residents resected 8 different tumors using the CAE NeuroVR virtual reality neurosurgical simulation platform (CAE Healthcare, Montréal, Québec and the National Research Council Canada, Boucherville, Québec). Position and force data were used to create force pyramids and quantify tumor quadrant force distribution. RESULTS: Force distribution quantification demonstrates the critical role that handedness and ergonomics play on psychomotor performance during simulated brain tumor resections. Neurosurgeons concentrate their dominant hand forces in a defined crescent in the lower right tumor quadrant. Nondominant force pyramids showed a central peak force application in all groups. Bimanual force pyramids outlined the combined impact of each hand. Distinct force pyramid patterns were seen when tumor stiffness, border complexity, and color were altered. CONCLUSION: Force pyramids allow delineation of specific tumor regions requiring greater psychomotor ability to resect. This information can focus and improve resident technical skills training.

Removal of lumber spine foreign body using minimal access system with navigation.

Removal of a foreign body from the spine is often time a surgical challenge. Recent developments in computer-assisted surgery (CAS) have brought major improvements into the operating room. Most Medical procedures nowadays take advantage of the minimal invasiveness, precision, velocity and interactivity provided by the computer-assisted systems. Minimally invasive techniques (MIT) like microscopy, stereotaxy, endoscopy and neuronavigation facilitate the procedures improve neurosurgical results and reduce operative complications. In this technical report we used minimal access system with navigation to remove a broken spinal needle at L4-L5 level from an asymptomatic lady post delivery using a custom-made navigation-mounted pituitary rongeur.

Neurosurgical Assessment of Metrics Including Judgment and Dexterity Using the Virtual Reality Simulator NeuroTouch (NAJD Metrics).

Advances in computer-based technology has created a significant opportunity for implementing new training paradigms in neurosurgery focused on improving skill acquisition, enhancing procedural outcome, and surgical skills assessment. NeuroTouch is a computer-based virtual reality system that can generate output data known as metrics from operator performance during simulated brain tumor resection. These measures of quantitative assessment are used to track and compare psychomotor performance during simulated operative procedures. Data output from the NeuroTouch system is recorded in a comma-separated values file. Data mining from this file and subsequent metrics development requires the use of sophisticated software and engineering expertise. In this article, we introduce a system to extract a series of new metrics using the same data file using Excel software. Based on the data contained in the NeuroTouch comma-separated values file, 13 novel NeuroTouch metrics were developed and classified. Tier 1 metrics include blood loss, tumor percentage resected, and total simulated normal brain volume removed. Tier 2 metrics include total instrument tip path length, maximum force applied, sum of forces utilized, and average forces utilized by the simulated ultrasonic aspirator and suction instrument along with pedal activation frequency of the ultrasonic aspirator. Advanced tier 2 metrics include instrument tips average separation distance, efficiency index, ultrasonic aspirator path length index, coordination index, and ultrasonic aspirator bimanual forces ratio. This system of data extraction provides researchers expedited access for analyzing the data files available for NeuroTouch platform to assess the multiple psychomotor and cognitive neurosurgical skills involved in complex surgical procedures.

Assessing bimanual performance in brain tumor resection with NeuroTouch, a virtual reality simulator.

BACKGROUND: Validated procedures to objectively measure neurosurgical bimanual psychomotor skills are unavailable. The NeuroTouch simulator provides metrics to determine bimanual performance, but validation is essential before implementation of this platform into neurosurgical training, assessment, and curriculum development. OBJECTIVE: To develop, evaluate, and validate neurosurgical bimanual performance metrics for resection of simulated brain tumors with NeuroTouch. METHODS: Bimanual resection of 8 simulated brain tumors with differing color, stiffness, and border complexity was evaluated. Metrics assessed included blood loss, tumor percentage resected, total simulated normal brain volume removed, total tip path lengths, maximum and sum of forces used by instruments, efficiency index, ultrasonic aspirator path length index, coordination index, and ultrasonic aspirator bimanual forces ratio. Six neurosurgeons and 12 residents (6 senior and 6 junior) were evaluated. RESULTS: Increasing tumor complexity impaired resident bimanual performance significantly more than neurosurgeons. Operating on black vs glioma-colored tumors resulted in significantly higher blood loss and lower tumor percentage, whereas altering tactile cues from hard to soft decreased resident tumor resection. Regardless of tumor complexity, significant differences were found between neurosurgeons, senior residents, and junior residents in efficiency index and ultrasonic aspirator path length index. Ultrasonic aspirator bimanual force ratio outlined significant differences between senior and junior residents, whereas coordination index demonstrated significant differences between junior residents and neurosurgeons. CONCLUSION: The NeuroTouch platform incorporating the simulated scenarios and metrics used differentiates novice from expert neurosurgical performance, demonstrating NeuroTouch face, content, and construct validity and the possibility of developing brain tumor resection proficiency performance benchmarks.

Multi-level Split Cord Malformation: Do We Need a New Classification?

Split cord malformations (SCMs) are thought to be rare abnormalities representing 3.8-5% of all spinal cord anomalies. The prevalence is estimated to be 1 in 5499 live births (0.02%), with a slight female predominance (1.3:1). Although the estimates of prevalence vary, Type I SCM occurs more frequently than Type II SCM. In this paper, we are reporting the clinical presentation and imaging findings of multi-level SCM in a 27-year-old male. A literature review of the embryological background of SCM and pathological hypothesis for this entity is provided. A systematic review has been conducted to identify multi-level SCM cases reported in the literature, followed by proposing a new classification system to further our understanding and management of SCMs.