Minimally Invasive Augmented Fixation for Anatomical Reduction of Grade 2 and Grade 3 Listhesis in Patients with Osteoporosis

Study design: A retrospective study.

Purpose: To study the efficacy of augmented fixation for anatomical reduction of grade 2 and grade 3 listhesis in patients with osteoporosis.

Overview of literature: Spondylolisthesis in osteoporotic patients requiring spinal fixation are associated with complications such as loss of surgical construct stability, screw pulling out, and screw loosening. Augmented fixation is a novel strategy to achieve necessary construct integrity.

Methods: Thirteen consecutive patients with grade 2 or grade 3 listhesis, with proven osteoporosis on dual energy X-ray absorptiometry (DEXA) scan, and who underwent augmented fixation for reduction of listhesis were retrospectively analyzed. In all patients, surgical access was achieved with a fixed 22 mm tubular retractor. A modified technique of bilateral, sequential, transforaminal decompression and discectomy, followed by reduction of listhesis using unilaterally placed augmented screws was employed in all the cases. Patients were followed up with plain X-rays at regular intervals to assess for implant stability and fusion status. All patients were started on medical treatment for osteoporosis.

Results: The mean age of the patients was 52.46 years, with 12 females and one male. The median T-score on DEXA scan was -3.0. Of the 13 patients, listhesis was at L4-L5 in five and at L5-S1 in eight. Nine patients had grade 2 listhesis, while four patients had grade 3 listhesis. Complete reduction was achieved in 10 patients. The median duration of follow-up was 18 months. Postoperative outcomes were satisfactory in all cases.

Conclusions: Augmented fixation is a useful technique for achieving anatomical reduction of listhesis in patients with osteoporosis.