Delayed chylous fluid leakage at the surgical site following thoracic corpectomy via a lateral extracavitary approach: illustrative case.

BACKGROUND: Chylous fluid leakage following spinal surgery is a rare and potentially difficult-to-manage complication that can lead to wound complications, pain, or nutritional deficiencies. Although the thoracic duct is localized near the thoracic spine, reports of thoracic duct injuries secondary to posterior thoracic spine surgery are rare. OBSERVATIONS: The authors present the case of a 57-year-old male with a known history of metastatic renal cell carcinoma to the thoracic spine who had undergone a thoracolumbar fusion with thoracic corpectomy and presented with concern for a chyle leak almost a year after his surgery. The patient had a complicated oncological history and underwent decompression and fusion to treat his significant thoracic metastatic disease. A year later, he presented with back pain and a significant fluid collection at the surgical site, which was drained and found to be consistent with chyle. The patient was treated conservatively, and imaging of the thoracic duct a few months later demonstrated no direct injury, likely indicating either transient injury or potential obstruction of the thoracic duct from metastatic disease. LESSONS: This case demonstrates a rare, potential complication when treating extensive thoracic metastatic disease as well as the workup and potential treatments when facing thoracic duct injury. https://thejns.org/doi/10.3171/CASE24280.

Real-Time multifaceted artificial intelligence vs In-Person instruction in teaching surgical technical skills: a randomized controlled trial.

Trainees develop surgical technical skills by learning from experts who provide context for successful task completion, identify potential risks, and guide correct instrument handling. This expert-guided training faces significant limitations in objectively assessing skills in real-time and tracking learning. It is unknown whether AI systems can effectively replicate nuanced real-time feedback, risk identification, and guidance in mastering surgical technical skills that expert instructors offer. This randomized controlled trial compared real-time AI feedback to in-person expert instruction. Ninety-seven medical trainees completed a 90-min simulation training with five practice tumor resections followed by a realistic brain tumor resection. They were randomly assigned into 1-real-time AI feedback, 2-in-person expert instruction, and 3-no real-time feedback. Performance was assessed using a composite-score and Objective Structured Assessment of Technical Skills rating, rated by blinded experts. Training with real-time AI feedback (n = 33) resulted in significantly better performance outcomes compared to no real-time feedback (n = 32) and in-person instruction (n = 32), .266, [95% CI .107 .425], p < .001; .332, [95% CI .173 .491], p = .005, respectively. Learning from AI resulted in similar OSATS ratings (4.30 vs 4.11, p = 1) compared to in-person training with expert instruction. Intelligent systems may refine the way operating skills are taught, providing tailored, quantifiable feedback and actionable instructions in real-time.

Do expandable cage size and number of cages matter in transforaminal lumbar interbody fusion at L5-S1? A comparative biomechanical analysis using finite element modeling.

OBJECTIVE: Expandable transforaminal lumbar interbody fusion (TLIF) cages were designed to address the limitations of static cages. Bilateral cage insertion can potentially enhance stability, fusion rates, and segmental lordosis. However, the benefits of unilateral versus bilateral expandable cages with varying sizes in TLIF remain unclear. This study used a validated finite element spine model to compare the biomechanical properties of L5-S1 TLIF by using differently sized expandable cages inserted unilaterally or bilaterally. METHODS: A finite element model of X-PAC expandable lumbar cages was created and used at the L5-S1 level. This model had cage dimensions of 9 mm in height, 15° in lordosis, and varying widths and lengths. Various placements (unilateral vs bilateral) and sizes were examined under pure moment loading to evaluate range of motion, adjacent-segment motion, and endplate stress. RESULTS: Stability at the L5-S1 level decreased when smaller cages were used in both the unilateral and bilateral cage models. In the unilateral model, cage 1 (the smallest cage) resulted in 47.9% more motion at the L5-S1 level compared to cage 5 (the largest cage) in flexion, as well as 64.8% more motion in extension. Similarly, in the bilateral TLIF model, bilateral cage 1 led to 49.4% more motion at the L5-S1 level in flexion and 73.4% more motion in extension compared to bilateral cage 5. Unilateral insertion of cage 5 provided superior stability in flexion and surpassed cages 1-3 in extension when compared to cages inserted either unilaterally or bilaterally. Reduced motion at L5-S1 correlated with increased adjacent-segment motion at L4-5. Bilateral TLIF resulted in greater adjacent-segment motion compared to unilateral TLIF with the same-size cages. Inferior endplates experienced higher stress during flexion and extension than superior endplates, with this difference being more pronounced in the bilateral model. In bilateral cage placement, stress differences ranged from 46.3% to 60.0%, while they ranged from 1.1% to 9.6% in unilateral cages. Qualitative analysis revealed increased focal stress in unilateral cages versus bilateral cages. CONCLUSIONS: The authors' study shows that using a large unilateral TLIF cage may offer better stability than the bilateral insertion of smaller cages. While large bilateral cages increase adjacent-segment motion, they also provide a uniform stress distribution on the endplates. These findings deepen our understanding of the biomechanics of the available expandable TLIF cages.

Management of a recurrent spinal arachnoid cyst presenting as arachnoiditis in the setting of spontaneous spinal subarachnoid hemorrhage: illustrative case.

BACKGROUND: Spontaneous spinal subarachnoid hemorrhage is a rare pathological entity with a variety of presentations depending on the underlying etiology, which often remains cryptogenic. The literature is sparse regarding the most efficacious treatment or management option, and there is no consensus on follow-up time or modalities. Additionally, there are very few reports that include operative videos, which is provided herein. OBSERVATIONS: The authors present a case of spontaneous spinal subarachnoid hemorrhage without an underlying etiology in a patient with progressive myelopathy, back pain, and lower-extremity paresthesias. She presented to our institution, and because of progressive worsening of her symptoms and the development of compressive arachnoid cysts, she underwent thoracic laminectomies for evacuation of subdural fluid, fenestration of the arachnoid cysts, and lysis of significant arachnoid adhesions. Her clinical course was further complicated by the recurrence of worsening myelopathy and the development of a large compressive arachnoid cyst with further arachnoiditis. The patient underwent repeat surgical intervention for cyst decompression with an improvement in symptoms. LESSONS: This case highlights the importance of long-term follow-up for these complicated cases with an emphasis on repeat magnetic resonance imaging. Unfortunately, surgical intervention is associated with short-term relief of the symptoms and no significant nonoperative management is available for these patients.

Effect of Feedback Modality on Simulated Surgical Skills Learning Using Automated Educational Systems- A Four-Arm Randomized Control Trial.

OBJECTIVE: To explore optimal feedback methodologies to enhance trainee skill acquisition in simulated surgical bimanual skills learning during brain tumor resections. HYPOTHESES: (1) Providing feedback results in better learning outcomes in teaching surgical technical skill when compared to practice alone with no tailored performance feedback. (2) Providing more visual and visuospatial feedback results in better learning outcomes when compared to providing numerical feedback. DESIGN: A prospective 4-parallel-arm randomized controlled trial. SETTING: Neurosurgical Simulation and Artificial Intelligence Learning Centre, McGill University, Canada. PARTICIPANTS: Medical students (n = 120) from 4 Quebec medical schools. RESULTS: Participants completed a virtually simulated tumor resection task 5 times while receiving 1 of 4 feedback based on their group allocation: (1) practice-alone without feedback, (2) numerical feedback, (3) visual feedback, and (4) visuospatial feedback. Outcome measures were participants' scores on 14-performance metrics and the number of expert benchmarks achieved during each task. There were no significant differences in the first task which determined baseline performance. A statistically significant interaction between feedback allocation and task repetition was found on the number of benchmarks achieved, F (10.558, 408.257)=3.220, p < 0.001. Participants in all feedback groups significantly improved their performance compared to baseline. The visual feedback group achieved significantly higher number of benchmarks than the practice-alone group by the third repetition of the task, p = 0.005, 95%CI [0.42 3.25]. Visual feedback and visuospatial feedback improved performance significantly by the second repetition of the task, p = 0.016, 95%CI [0.19 2.71] and p = 0.003, 95%CI [0.4 2.57], respectively. CONCLUSION: Simulations with autonomous visual computer assistance may be effective pedagogical tools in teaching bimanual operative skills via visual and visuospatial feedback information delivery.