Study design:

Prospective, observational.

Objectives:

The aim of our study was to assess the amount of reduction in lean muscle mass (LMM) of multifidus muscle (MFM) between conventional open Transforaminal lumbar interbody fusion (CO-TLIF) as compared to Minimally invasive spine Transforaminal lumbar interbody fusion (MIS-TLIF).

Methods:

This study was conducted between 2017 and 2020. It included 100 patients divided into two groups, 50 patients treated with CO-TLIF, 50 treated with MIS-TLIF. Only patients undergoing single level, primary lumbar fusion at L4-5 or L5-S1 level for degenerative pathologies were included. All patients were assessed by magnetic resonance imaging (MRI) scans 1-year post surgery. Measurements were performed using ImageJ image processing program.

Results:

Mean percentage reduction in LMM in CO-TLIF group was 45.52 ± 12.36% and MIS-TLIF group was 25.83 ± 9.64% [statistically significant (t = 8.78, P < .001)]. Mean percentage reduction in LMM on side of cage insertion was 39.63 ± 15.96% and opposite side was 31.40 ± 15.01% [statistically significant (t = 9.06, P < .001)]. Mean reduction of LMM among males was 29.38 ± 15.23% and females was 40.42 ± 12.67% [statistically significant (t = -3.95, P < .001)].We observed significant but weak degree of correlation between age and percentage reduction of LMM (r = .22, P = .028).

Conclusion:

Mean reduction in LMM was greater in CO-TLIF group as compared to MIS-TLIF. There was greater reduction in LMM in females and on side of cage insertion. We also found greater reduction in LMM with increasing age in both groups.