Virtual, Augmented, and Mixed Reality Applications for Surgical Rehearsal, Operative Execution, and Patient Education in Spine Surgery: A Scoping Review.

Background and Objectives: Advances in virtual reality (VR), augmented reality (AR), and mixed reality (MR) technologies have resulted in their increased application across many medical specialties. VR's main application has been for teaching and preparatory roles, while AR has been mostly used as a surgical adjunct. The objective of this study is to discuss the various applications and prospects for VR, AR, and MR specifically as they relate to spine surgery. Materials and Methods: A systematic review was conducted to examine the current applications of VR, AR, and MR with a focus on spine surgery. A literature search of two electronic databases (PubMed and Scopus) was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The study quality was assessed using the MERSQI score for educational research studies, QUACS for cadaveric studies, and the JBI critical appraisal tools for clinical studies. Results: A total of 228 articles were identified in the primary literature review. Following title/abstract screening and full-text review, 46 articles were included in the review. These articles comprised nine studies performed in artificial models, nine cadaveric studies, four clinical case studies, nineteen clinical case series, one clinical case-control study, and four clinical parallel control studies. Teaching applications utilizing holographic overlays are the most intensively studied aspect of AR/VR; the most simulated surgical procedure is pedicle screw placement. Conclusions: VR provides a reproducible and robust medium for surgical training through surgical simulations and for patient education through various platforms. Existing AR/MR platforms enhance the accuracy and precision of spine surgeries and show promise as a surgical adjunct.

Utilization of Augmented Reality Head-Mounted Display for the Surgical Management of Thoracolumbar Spinal Trauma.

Background and Objectives: Augmented reality head-mounted display (AR-HMD) is a novel technology that provides surgeons with a real-time CT-guided 3-dimensional recapitulation of a patient's spinal anatomy. In this case series, we explore the use of AR-HMD alongside more traditional robotic assistance in surgical spine trauma cases to determine their effect on operative costs and perioperative outcomes. Materials and Methods: We retrospectively reviewed trauma patients who underwent pedicle screw placement surgery guided by AR-HMD or robotic-assisted platforms at an academic tertiary care center between 1 January 2021 and 31 December 2022. Outcome distributions were compared using the Mann-Whitney U test. Results: The AR cohort (n = 9) had a mean age of 66 years, BMI of 29.4 kg/m2, Charlson Comorbidity Index (CCI) of 4.1, and Surgical Invasiveness Index (SII) of 8.8. In total, 77 pedicle screws were placed in this cohort. Intra-operatively, there was a mean blood loss of 378 mL, 0.78 units transfused, 398 min spent in the operating room, and a 20-day LOS. The robotic cohort (n = 13) had a mean age of 56 years, BMI of 27.1 kg/m2, CCI of 3.8, and SII of 14.2. In total, 128 pedicle screws were placed in this cohort. Intra-operatively, there was a mean blood loss of 432 mL, 0.46 units transfused units used, 331 min spent in the operating room, and a 10.4-day LOS. No significant difference was found between the two cohorts in any outcome metrics. Conclusions: Although the need to address urgent spinal conditions poses a significant challenge to the implementation of innovative technologies in spine surgery, this study represents an initial effort to show that AR-HMD can yield comparable outcomes to traditional robotic surgical techniques. Moreover, it highlights the potential for AR-HMD to be readily integrated into Level 1 trauma centers without requiring extensive modifications or adjustments.

Metastasectomy for extracalvarial renal cell carcinoma.

Key Clinical Message: Palliative surgical resection of extra-calvarial metastatic lesions from renal cell tumors is crucial for controlling metastatic spread, improving quality of life, and preventing associated morbidity. Careful surgical planning, including selective preoperative embolization and controlled resection around critical structures such as the sagittal sinus, is essential for successful outcomes. Cranioplasty with Titanium mesh and bone cement post-resection can provide symptomatic relief, better cosmesis, and overall improved quality of life. Abstract: Renal cell carcinomas are aggressive tumors with distant systemic disease. The calvarium appears to be an unusual and rare site for distant metastasis. The treatment modalities are challenging and out of the normal realm for the management of these tumors. We report a case of a 63-year-old woman with a previous history of nephrectomy who presented with symptoms of severe headaches, and swelling of bi-frontal and bi-parietal scalp regions due to multifocal extracalvarial disease. Preoperative bilateral superficial temporal artery embolization was performed to control the intraoperative bleeding. Surgical technique has been described with the critical steps involved, and a literature review has been conducted. Palliative tumor resection surgery was performed to improve the patient's quality of life as well as to confirm the histopathological diagnosis. Gross total resection of the extracalvarial metastatic tumor was achieved. Biopsy confirmed renal cell tumor with the clear cell subtype. The patient recovered well from her surgery with slow healing of the scalp wound. At 6-month follow-up, no recurrence of the extracalvarial disease was observed on serial imaging. Extracalvarial metastasis is a rare presentation in renal cell carcinoma. Considering the inherent radioresistant nature of the tumor, palliative surgical resection can be offered to control the metastatic spread, relieve agonizing pain symptoms, and to improve the quality of life. Preoperative embolization helps to decrease intraoperative blood loss. Moreover, palliative surgical resection of extracalvarial diseases helps to treat the metastasis as well as avoiding the associated morbidity that may occur if left untreated.

Surgical Perfusion and Isolation of the Porcine Pancreas for Islet Isolation.

Pancreatic islet transplantation is an emerging treatment for type I diabetes; however, it is limited by donor matching and availability. Porcine islet xenotransplantation offers a promising alternative to allotransplantation, with the potential for large-scale production of on-demand, functional islets. The yield and viability of isolated islets is highly susceptible to the quality of the donor pancreas and the method of procurement, particularly the duration of warm-ischemia time. To improve organ preservation and subsequent islet yield and viability, we have developed a protocol for surgical perfusion and resection of the porcine pancreas. This protocol employs direct infrarenal aortic cannulation and organ perfusion to both minimize warm-ischemia time and simplify the procedure for operators who do not have extensive surgical expertise. Subsequent arterial perfusion of the pancreas via the aorta flushes stagnant blood from the microvasculature, thereby reducing thrombosis and oxidative damage to the tissue. This manuscript provides a detailed protocol for surgical perfusion and resection of the porcine pancreas, followed by islet isolation and purification.

Posterior Transdural Approach for Thoracic Corpectomies in the Setting of Complex Spine Deformity Reconstruction.

BACKGROUND AND OBJECTIVE: There are many surgical approaches for execution of a thoracic corpectomy. In cases of challenging deformity, traditional posterior approaches might not be sufficient to complete the resection of the vertebral body. In this technical note, we describe indications and technique for a transdural multilevel high thoracic corpectomy. METHODS: A 25-year-old man with a history of neurofibromatosis type 1 presented with instrumentation failure after a previous T1-T12 posterior spinal fusion, extensive laminectomy, and tumor resection. The patient presented with progressive back pain, had broad dural ectasia, and a progressive kyphotic rotational and anteriorly translated spinal deformity. To resect the medial-most aspect of the vertebral body, a bilateral extracavitary approach was attempted, but was found insufficient. A transdural approach was subsequently performed. A left paramedian durotomy was made, followed by generous arachnoid dissection, bilateral dentate ligament division, and T4 rootlet sacrifice to mobilize the spinal cord. A ventral durotomy was then made and the ventral dura was reflected over the spinal cord to protect it while drilling. The corpectomy was then completed. The ventral and dorsal durotomies were closed primarily and reinforced with fibrin glue and fibrin sealant patch. The corpectomy defect was filled with nonstructural autograft. RESULTS: The focal kyphosis was corrected with a combination of rod contouring, compression, and in situ bending. During the surgery, the patient had stable neuromonitoring data, and postoperatively had no neurological deficits. On follow-up until 1 year, the patient presented with no signs of cerebrospinal spinal leaks, no motor or sensory deficits, minimal incisional pain, and significantly improved posture. CONCLUSION: Complex high thoracic (T3-5) ventral pathology inaccessible via a bilateral extracavitary approach may be accessed via a transdural approach as opposed to an anterior/lateral transthoracic approach that requires mobilization of cardiovascular structures or scapula.

The Perfect Storm: An Unusual Cause of Intestinal Perforation in a Solid Organ Transplant Patient.

Immunosuppressants are used to prevent rejection in transplant patients. Many of these medications commonly cause gastrointestinal (GI) symptoms. We present a 38-year-old kidney and pancreas transplant recipient who had severe ulceration throughout his GI tract leading to perforations of his stomach and cecum, despite early discontinuation of mycophenolate mofetil-the most likely culprit medication. The ongoing injury observed despite holding mycophenolate suggests a possible compounding effect of tacrolimus and everolimus. Both these agents are underrepresented causes of GI injury. This perfect storm of agents may have accounted for the severity and extensive presentation observed in our patient.