Comparison of clinical outcomes following minimally invasive lateral interbody fusion stratified by preoperative diagnosis.

PURPOSE: Lumbar fusion has been shown to be effective in treating a variety of degenerative spinal conditions, though significant differences exist in the magnitude of clinical improvement across different surgical diagnoses. With modern, minimally disruptive approaches for fusion, diagnosis-specific differences in clinical improvement may be reduced. The purpose of this study is to report and compare interim clinical improvements in patients treated with XLIF for various degenerative lumbar conditions.

METHODS: 160 patients underwent XLIF for either degenerative spondylolisthesis (n = 68), degenerative disc disease (n = 20), adjacent segment disease (n = 26), or post-laminectomy syndrome (n = 46). Average age was 61 years and 66 % were female. Mean BMI was 28.9 kg/m(2). 37 % were smokers, 23 % had diabetes mellitus, 22 % had depression. Mean age was highest for ASD patients (66 years) and lowest for DDD patients (48 years) (p < 0.001). There were no other baseline demographic differences between groups. Patient-reported clinical outcomes measures were collected at baseline and prospectively at standard intervals. Interim results at an average of 19 months follow-up are reported here.

RESULTS: In total, 197 levels were treated with XLIF (mean 1.2 per patient). There were no cases of symptomatic pseudoarthrosis or implant/instrument failure. Overall, 1 patient (0.6 %) had a major complication and 12 % had a minor complication. Approach-related anterolateral thigh/groin sensory changes were present in 14 % and hip flexion weakness in 9 %. At last follow-up, overall ODI decreased 47 % (44.1-23.5), VAS LBP decreased 59 % (6.9-2.8), VAS LP decreased 56 % (7.1-3.1), and SF-36 PCS improved 40 % (30.9-43.2) (all p < 0.001). Baseline ODI was significantly lower for DDD patients (p = 0.052). At last follow-up, mean percent improvements on all outcomes were highest for DSP group, though not all differences were significant. Improvements between diagnostic groups were statistically different for LBP (p = 0.021), but were similar for all other clinical outcomes. Percentage of patients reaching MCID and SCB thresholds ranged from 60 to 95 % in clinical outcomes. Patient satisfaction for the entire group was 93 % when asked whether satisfied with surgical outcome.

CONCLUSIONS: XLIF has been demonstrated in the current series to lead to significant improvements in clinical outcomes and high rates of MCID and SCB and reduce the discrepancy in outcomes between well accepted and technically challenging indications compared to traditional open approaches for IBF. Complication rates were low, with only one patient in the series experiencing a major complication. Further investigation with larger cohorts and longer follow-up is warranted.