Clifton, William

Background Spinal subdural empyema rarely involves the spinal cord and may result in devastating neurological deficits. These lesions typically require prompt diagnosis, surgical evacuation, and antibiotic therapy. Here, we present the clinical course, imaging, and narrated operative video of a thoracic spinal subdural empyema initially diagnosed as an intramedullary neoplasm. Case Description A 73-year-old female presented with a 6-month history of worsening thoracic myelopathy; over the last few weeks, she rapidly developed paraplegia. She was initially diagnosed with an enlarging thoracic intramedullary mass. A spinal biopsy was performed for the presumptive diagnosis of primary intramedullary central nervous system lymphoma. However, at surgery, the thoracic lesion proved to be a chronic subdural empyema (i.e., surrounded by arachnoid granulations and soft-purulent tissue). Interestingly, the operative specimen failed to grow any specific organism. Conclusion Spinal subdural empyema should be one of the differential diagnoses considered for patients presenting with intradural spinal cord lesions.

Study Design: Systematic review and meta-analysis. Objective: To perform a systematic review of the clinical symptoms, radiographic findings, and outcomes after spinal decompression in B-cell lymphoma. Summary of Background Data: B-cell lymphoma is a potential cause of spinal cord compression that presents ambiguously with nonspecific symptoms and variable imaging findings. Surgical decompression is a mainstay for both diagnosis and management, especially in patients with acute neurological deficits; however, the efficacy of surgical intervention compared with nonoperative management is still unclear. Methods: The databases of Medline, PubMed, and the Cochrane Database of Systemic Reviews were queried for all articles reporting spinal B-cell lymphoma. Data on presenting symptoms, treatments, survival outcomes, and histologic markers were extracted. Using the R software “survival” package, we generated bivariate and multivariate Cox survival regression models and Kaplan-Meier curves. Results: In total, 65 studies were included with 72 patients diagnosed with spinal B-cell lymphoma. The mean age was 56.22 (interquartile range: 45.00–70.25) with 68% of patients being males and 4.2% of patients being immunocompromised. Back pain was the most common symptom (74%), whereas B symptoms and cauda equina symptoms were present in 6% and 29%, respectively. The average duration of symptoms before presentation was 3.81 months (interquartile range: 0.45–3.25). The most common location was the thoracic spine (53%), with most lesions being hyperintense (28%) on T2 magnetic resonance imaging. Surgical resection was performed in 83% of patients. Symptoms improved in 91% of patients after surgery and in 80% of patients treated nonoperatively. For all 72 patients, the overall survival at 1 and 5 years was 85% (95% CI: 0.749–0.953; n = 72) and 66% (95% CI: 0.512–0.847; n = 72), respectively. Conclusion: Although surgery is usually offered in patients with acute spinal cord compression from B-cell lymphoma, chemotherapy and radiation alone offer a hopeful alternative to achieve symptomatic relief, particularly in patients who are unable to undergo surgery.

BACKGROUND: Anterior approaches to the cervical spine are among the most common exposures by which neurosurgeons and orthopedic surgeons access the prevertebral space and ultimately the cervical disk and vertebral bodies. There is a paucity of literature describing the microanatomic fascial planes of the neck with respect to anterior cervical approaches. OBJECTIVE: To delineate the microanatomic connections of the cervical fascial planes pertinent to anterior cervical exposure. METHODS: Using a cadaveric model, original illustrations, the Visible Human Project, and an original surgical video, we demonstrate a stepwise method for identifying the correct planes for anterior cervical exposure. RESULTS: A step-by-step method for identifying the anterior cervical fascial planes intraoperatively is demonstrated. CONCLUSION: A comprehensive understanding of anterior cervical microsurgical anatomy is vital for performing a methodical yet efficient approach to the prevertebral space while minimizing retraction and iatrogenic injury to the surrounding neurovascular structures.

BACKGROUND: Graduate surgical education is highly variable across regions and institutions regarding case volume and degree of trainee participation in each case. Dedicated educational curriculum using cadaveric tissue has been shown to enhance graduate surgical training, however with associated financial and utility burden to the institution. OBJECTIVE: To investigate the utility of educational and cost applications of a novel method of combining mixed organic hydrogel polymers and 3-dimensional printed anatomic structures to create a complete “start-to-finish” simulation for resident education in spinal anatomy, instrumentation, and surgical techniques. METHODS: This qualitative pilot study investigated 14 international participants on achievement of objective and personal learning goals in a standardized curriculum using biomimetic simulation compared with cadaveric tissue. A questionnaire was developed to examine trainee evaluation of individual anatomic components of the biomimetic simulators compared with previous experience with cadaveric tissue. RESULTS: A total of 210 responses were acquired from 14 participants. Six participants originated from US residency education programs and 8 from transcontinental residency programs. Survey results for the simulation session revealed high user satisfaction. Score averages for each portion of the simulation session indicated learner validation of anatomic features for the simulation compared with previous cadaveric experience. Cost analysis resulted in an estimated savings of $10 833.00 for this single simulation session compared with previous cadaveric tissue sessions. CONCLUSION: The results of this study indicate a strong potential of establishing biomimetic simulation as a cost-effective and high-quality alternative to cadaveric tissue for the instruction of fundamental spine surgical techniques.

Abstract BACKGROUND Brain mapping is the most reliable intraoperative tool for identifying surrounding functional cortical and subcortical brain parenchyma. Brain mapping procedures are nuanced and require a multidisciplinary team and a well-trained neurosurgeon. Current training methodology involves real-time observation and operation, without widely available surgical simulation. OBJECTIVE To develop a patient-specific, anatomically accurate, and electrically responsive biomimetic 3D-printed model for simulating brain mapping. METHODS Imaging data were converted into a 2-piece inverse 3D-rendered polyvinyl acetate shell forming an anatomically accurate brain mold. Functional and diffusion tensor imaging data were used to guide wire placement to approximate the projection fibers from the arm and leg areas in the motor homunculus. Electrical parameters were generated, and data were collected and processed to differentiate between the 2 tracts. For validation, the relationship between the electrical signal and the distance between the probe and the tract was quantified. Neurosurgeons and trainees were interviewed to assess the validity of the model. RESULTS Material testing of the brain component showed an elasticity modulus of 55 kPa (compared to 140 kPa of cadaveric brain), closely resembling the tactile feedback a live brain. The simulator's electrical properties approximated that of a live brain with a voltage-to-distance correlation coefficient of r 2 = 0.86. Following 32 neurosurgeon interviews, ∼96% considered the model to be useful for training. CONCLUSION The realistic neural properties of the simulator greatly improve representation of a live surgical environment. This proof-of-concept model can be further developed to contain more complicated tractography, blood and cerebrospinal fluid circulation, and more in-depth feedback mechanisms.

Background: During awake craniotomy, securing the patient’s airway might be necessary electively or emergently. The objective of this study was to compare the feasibility of airway management using a laryngeal mask airway (LMA) and 4 alternative airway management techniques in an awake craniotomy simulation. Methods: After completing a questionnaire, 9 anesthesia providers attempted airway management in a cadaver positioned to simulate awake craniotomy conditions. Following the simulation, participants rated and ranked the devices in their order of preference. Results: Only 3 approaches resulted in the successful securement of an airway device for 100% of participants: LMA (median; interquartile range time to secure the airway 6 s, 5 to 10 s), fiberoptic bronchoscopy through an LMA (41 s; 23 to 51 s), and video laryngoscopy (49 s; 43 to 127 s). In contrast, the oral and nasal fiberoptic approaches demonstrated only 44.4% (154.5 s; 134.25 to 182 s) and 55.6% (75 s; 50 to 117 s) success rates, respectively. The LMA was the fastest and most reliable primary method to secure the airway (P=0.001). After the simulation, 100% of participants reported that an LMA would be their first choice for emergency airway management, followed by fiberoptic intubation through the LMA (7 of 9 participants) if the LMA failed to properly seat. Conclusions: We demonstrated that an LMA was the fastest and most reliable primary method to secure an airway in a laterally positioned cadaver with 3-pin skull fixation. Fiberoptic and video laryngoscope airway equipment should be readily available during awake craniotomy procedures, and an attempt to visualize the vocal cords through the LMA should be attempted before removing it for alternative techniques.

Abstract Commercial central line vascular access trainers are available but have significant limitations including cost, size, and limited durability when used for the complete procedure. A unique central venous access trainer was constructed using silicone loaf pan, ballistic gel, copper pipe and aluminum rods as vessels conduits, with varying inserts including latex and silicone to simulate different vascular structures, and the use of camouflage. This trainer is inexpensive, portable, reusable, allows the complete procedure to be simulated, and may be customized to the specific needs of the learner. The assembled simulator demonstrated excellent ultrasound visualization, including varying size and vessel character, allowed modification to specific learner needs, while at the same time being light-weight, portable, inexpensive, and reusable. A moderate-fidelity central venous access simulator can be constructed in a cost-effective manner, which can be optimized to the learner skill level and allows the entire procedure to be completed on the simulator.

Abstract We present a surgical video illustrating the technique for en bloc resection of an intradural-extramedullary lumbar tumor. The patient is a 63-yr-old woman presenting with worsening bilateral leg pain. Imaging of her lumbar spine showed an enhancing, circumscribed intradural-extramedullary tumor compressing her cauda equina at the L2 level. With informed patient consent, an L1-L3 laminectomy was performed, and intraoperative ultrasound provided the tumor location in order to plan the dural opening as well as define the tumor boundaries with respect to the surrounding nerve roots. The nerve roots were found to be dorsal to the tumor on the ultrasound and appeared to be separate from the tumor capsule. After the dura was opened, the nerve roots were dissected from the tumor capsule and the filum was identified at its proximal and distal portions relative to the mass. The tumor appeared to be arising from the filum itself. Intraoperative electromyography monitoring and stimulation identified the motor roots around the filum and were dissected away. The filum was isolated and cut proximally in order to prevent upward displacement of the mass above the dural opening. The distal portion was then cut and the tumor was removed en bloc. The patient had good postoperative relief of her leg pain and no new neurologic or genitourinary complications. This case highlights the preoperative and intraoperative surgical planning as well as detailed technical aspects of en bloc intradural-extramedullary lumbar tumor resection with preservation of the tumor capsule in order to achieve gross total resection.