General Session: MIS-4
Presented by: S. Osman - View Audio/Video Presentation (Members Only)
S. Osman(1,2), O. Ojeyemi(1,3), A. Malik(4), S. Sherlekar(4)
(1) American Spine, Orthopedic Surgery, Frederick, MD, United States
(2) Frederick Memorial Hospital, Orthopedic Surgery, Frederick, MD, United States
(3) Frederick Memorial Hospital, Frederick, MD, United States
(4) American Spine, Pain Medicine, Frederick, MD, United States
Background: The lumbosacral junction is a difficult area for spine surgery because of the complex anatomy. In the era of minimally invasive spine surgery, the presence of a tall iliac wing has, at the level of lumbosacral junction, creates a major obstacle in the paths of two of the major approaches, namely, the direct lateral and percutaneous posterolateral endoscopic approaches. While alternative approaches such as mini-anterior retroperitoneal, and the pre-sacral approaches are indeed less traumatic than the traditional posterior and anterior approaches, they do involve access through anatomical areas with potentially serious complications.
Purpose: To determine the feasibility of percutaneous, endoscopic trans-iliac, transforaminal, L5-S1 discectomy, foraminal decompression and interbody fusion.
Study Design: Prospective case series study.
Materials and Methods: 33 consecutive patients undergoing trans-iliac approach to L5-S1 disc and foramen were prospectively studied. Pre- and post-operative visual analogue scale (VAS); pre- and post-operative Oswestry Disability Index (ODI); estimated blood loss; operating time; Access Time/Cure Time ratio; and complications were obtained for the study. Indications for surgery included tall iliac crest obstructing postero-lateral approach to L5-S1 (and occasionally L4-5 disc) foramen and disc, preventing placement of the interbody device anteriorly and centrally in the disc space. Pre-operative MRI and/or CT scan was used to determine the need for trans-iliac access. The procedure was performed with the patient in prone position and under general anesthesia for decompression and fusion. The trans-iliac access was established posterolaterally with a cannulated drill or core drill through the iliac wing. Once the trans-iliac window had been created, the rest of the procedure proceeded as for percutaneous endoscopically assisted transforaminal decompression and interbody fusion.
Results: 33 patients (16 male and 17 female) participated in the study. Mean age was 51.4 years, and mean follow-up was 17.4 months. 10 and 23 patients were operated on in ambulatory surgery center and hospital, respectively. Fused levels include 10 L5-S1 level, 16 L4-S1 levels, 6 L3-S1 levels, and 1 L2-S1 levels. Mean blood loss was 75 ml (range = 50 -150 ml.). Average operating time was 97 minutes (range = 66 - 116). Access time/Cure Time ratio was 0.37. The VAS for back and leg pain significantly improved post-operatively in all patients. The ODI dropped by an average of 4.1% post-operatively (56.4% to 15.3%). Complications included dysesthesia in 9 patients which resolved within 2 months post-operatively. One patient required revision of the L5-S1 interbody cage following a fall. No patient required blood transfusion post-operatively.
Conclusion: Endoscopically assisted trans-osseous interbody fusion of the L5-S1 disc and foramen is feasible and safe in the hands of properly trained surgeon. Decompression and interbody fusion can be safely performed via trans-iliac access with minimal blood loss, and in a short operative time. The limitation of the direct lateral approach imposed by the iliac bone is overcome. The risks of trans-canal, retro-peritoneal, and pre-sacral approaches are avoided.