Expandable spacers provide better functional outcomes than static spacers in minimally invasive transforaminal lumbar interbody fusion.

Background: Transforaminal lumbar interbody fusion is an effective and frequently performed surgical treatment of chronic lower back pain. Expandable interbody spacers are designed to create greater disc height through expansion. It remains unclear whether the benefits of expandable technology will translate into clinical benefits. The current study compares expandable to static interbody spacers.

Methods: This is a retrospective study of 99 patients (48 static and 51 expandable) at a single site. Radiographs were collected preoperatively and at 3 months postoperatively. Standard of care at this site requires radiographs to be taken past 3 months only if patients are suffering from a severe recurrence of symptoms. Patient reported outcomes, Oswestry disability index (ODI) and visual analog scale (VAS), were collected preoperatively, at 1 and 3 months postoperatively. Patients were contacted by the surgeon and patient reported outcomes were collected at a final time point. Average final follow-up for was 67.1±16.3 months and for expandable patients it was 43.0±4.2 months.

Results: At 3 months postoperatively and at final follow-up, patients treated with expandable interbody spacers had significantly lower average ODI scores than patients with static interbody spacers. Both groups reported significant reductions in VAS scores through all follow-up. At 4 years postoperative 8 static group patients and 3 expandable group patients returned for recurrence of symptoms.

Conclusions: Expandable interbody spacers in this study were found to be comparable to static interbody spacers, with improvements in VAS and ODI scores.