PURPOSE

Conventional lumbar arthrodesis for the treatment of degenerative spondylolisthesis (DS) is associated with high complication rates and variable clinical efficacy. Modern minimally invasive (MIS) approaches may reduce the morbidity and produce greater clinical improvement compared to traditional surgical techniques. The objective of this study is to report radiographic outcomes and evaluate clinical improvements in the context of substantial clinical benefit for DS patients treated with a MIS 90° lateral, transpsoas approach for lumbar interbody fusion.

METHODS

From 2005 to 2011, 60 consecutive patients were treated with MIS lateral interbody fusion for Grade I or II DS at a single institution. Mean patient age was 68 years, 75 % were female, and 30 % had undergone previous lumbar surgery. A total of 71 levels were treated, supplemental posterior fixation was used in 57 (95 %) cases, and 26 (43 %) patients underwent additional direct posterior decompression.

RESULTS

Average follow-up was 20.3 months. Average ORT, EBL, and LOS were 206 min, 83 cc, and 1.29 days, respectively. Complications occurred in 3 (5 %) patients. Transient approach-related thigh/groin pain was observed in 5 (8 %) cases. There were no cases of pseudoarthrosis. At 1 year, LBP improved 71 %, LP improved 68 %, ODI decreased 52 %, and SF-36 PCS and MCS improved 43 and 21 %, respectively. Substantial clinical benefit was met by 94.7 % of patients on NRS LBP, by 84.6 % on NRS LP, by 83.7 % on ODI, and by 66.7 % on SF-36 PCS. Disc height increased 71 % and segmental lordosis increased 27.8 % at treated levels. Foraminal height, width, and volume increased 19.7, 18.0, and 39.6 %, respectively. Slip improved 60.7 % with interbody fusion only and further improved to 69.2 % after the placement of supplemental instrumentation.

CONCLUSIONS

MIS lateral interbody fusion in the treatment of DS resulted in significant improvements in clinical and radiographic outcomes, with a low complication rate and a high proportion of patients achieving substantial clinical benefit.