Purpose: To evaluate the learning curve for exoscope and three-dimensional (3D) 4K hybrid visualization in terms of operating time, advantages, disadvantages, and surgical complications in tubular-access minimally invasive spine surgery (MISS) and to assess surgeon satisfaction with image quality, ergonomics, and ability to perform target site treatment.
Overview of Literature: Working through tubular retractors poses a challenge. The extreme angulations during microsurgical decompression, especially contralateral decompression, require surgeons to work non-ergonomically. An exoscope allows surgeons to work ergonomically and independently of the microscope oculars as visualizations are now provided by large 3D 4K monitors. However, the value and efficacy of solely depending on an exoscope and 3D 4K monitors during microsurgical work are still unknown.
Methods: Seventy-four patients (99 levels) underwent trans-tubular MISS between March 2018 and January 2019. Five patients were excluded: one had pyogenic discitis, two had revisions, and two were trans-tubular transoral. In total, we analyzed 69 for operating time, blood loss, and complications. The learning curve graph was plotted using the surgical time for each procedure. Surgeons were asked to rate their satisfaction with image quality, ability to maintain ergonomic posture, and efficient target site treatment.
Results: For tubular microdiscectomy, the operating time plateaued after six cases, and for tubular decompression and minimally invasive transforaminal lumbar interbody fusion, the operating time plateaued after nine cases. Mean operating time was significantly reduced after the plateau. Complications included four cases of dural tear. All patients improved symptomatically, and there were no postoperative neurological deficits.
Conclusions: Use of the exoscope has a short learning curve. Surgeons benefit from improved ergonomic posture during surgery, and resident teaching appears to be good. The only drawback is the need to rearrange the operating table setup. Complications were comparable to those when using the surgical microscope. An exoscope with hybrid digital visualization provides excellent visualization, depth perception, clarity, and precision target site treatment.
Material and Methods: A retrospective study was conducted in our department from the data collected in the period between 1997 and 2010. There were 86 cases of infected non-union of the tibia, in patients of the age group 18 to 65 years, with a minimum two-year follow-up. Group A consisted of cases treated by ASRL (n=46), and Group B, of cases by IBT (n=40). The non-union following both open and closed fractures had been treated by plate osteosynthesis, intra-medullary nails and primary Ilizarov fixators. Radical debridement was done and fragments stabilised with ring fixators. The actual bone gap and limb length discrepancy were measured on the operating table after debridement. In ASRL acute docking was done for defects up to 3cm, and subacute docking for bigger gaps. Corticotomy was done once there was no infection and distraction started after a latency of seven days. Dynamisation was followed by the application of a patellar tendon bearing cast for one month after removal of the ring with the clinico-radiological union.
Results: The bone loss was 3 to 8cm (4.77±1.43) in Group A and 3 to 9cm (5.31± 1.28) in Group B after thorough debridement. Bony union, eradication of infection and primary soft- tissue healing was 100%, 85% and 78% in Group A and 95%, 60%, 36% in Group B respectively. Nonunion at docking site, equinus deformity, false aneurysm, interposition of soft-tissue, transient nerve palsies were seen only in cases treated by IBT.
Conclusion: IBT is an established method to manage gap non-union of the tibia. In our study, complications were significantly higher in cases where IBT was employed. We, therefore, recommend ASRL with an established protocol for better results in terms of significantly less lengthening index, eradication of infection, and primary soft tissue healing. ASRL is a useful method to bridge the bone gap by making soft tissue and bone reconstruction easier, eliminating the disadvantages of IBT.