Efficacy of less Invasive modified O-arm navigated delta fixation in osteoporotic high-grade spondylolisthesis: "a LIMO delta technique".

purposeIn 1994, the technique of transdiscal screws fixation in spondylolisthesis was introduced but did not gained popularity as it failed to address problems with spinal sagittal imbalance, retroverted pelvis, pseudoarthrosis, implant failure and neural injury. Majority of problems were due to lack of clear indications; hence, in this study, with modification of traditional technique and use of O-arm navigation for selected group of patients, we have addressed the above problems and given good to excellent functional outcomes.

methodsWe did prospective study on 15 patients with osteoporotic high-grade spondylolisthesis Meyerding grade 3 & 4 admitted in period 2020-2021. Intraoperative assessment was done in form of blood loss, incision length, operative time and complications. The preoperative & postoperative assessment was done in the form of clinical and radiological parameters.

resultsThe average follow-up was of 21.2 months (18-24 months). There was no significant difference between pre- & postoperative spinopelvic parameters. Intraoperative average blood loss was 100 ml (90-120 ml) with mean surgical time of 138 min (120-150 min). Incision length was about 5-6-cms-posterior midline with two paraspinal 1-cm incisions for transdiscal screws. Patients were mobilized on postoperative day-2. There was statistically significant improvement in mean ODI, COMI and VAS for LBP and radicular pain with no intra- or postoperative complication observed till latest follow-up with all patients showing solid monoblock fusion on 1-year follow-up CT scan.

conclusionsLIMO delta technique is a newly modified version of conventional transdiscal screw technique. Minimal incision, decreased blood loss & operative time with in situ 3-column rigid fixation and solid fusion minimizing risk of complications makes this novel technique safer, simpler & effective in osteoporotic HGS.