“Short-segment lumbar fusion” vs.“microsurgical bilateral decompression via unilateral approach” after removal of the spinal fixators in patients with adjacent segment disease: clinical retrospective study

In cases where adjacent segment disease (ASD) develops following lumbar fusion surgery, various surgical approaches can be employed. In such cases, removal of the instrumentation can positively impact lumbar pain syndrome. One frequently used method is short-segment fixation-decompression (SSFD). One of minimally invasive methods is microsurgical bilateral decompression via unilateral approach (MBDU).This study aims to determine which method is more effective and safe in cases that developed ASD following fusion surgery by comparing SSFD and MBDU after instrumentation removal. A retrospective analysis was conducted on 47 cases treated with SSFD and 29 cases treated with MBDU. The groups were analyzed for gender, age, preoperative symptom duration, duration of hospitalization, and Visual Analogue Scale (VAS) scores and Oswestry Disability Index (ODI) scores during the preoperative and postoperative intermittent follow-up periods. Duration of hospitalization was higher in the SSFD group compared to the MBDU group (p=<0.001 CI = 56,42 - 76,24 and 22,04- 25,13 respectively), mean transverse canal diameter ratio in the decompressed segment was lower in the SSFD group (p = 0,03 IC = 0,24 - 0,31 for SSFD y 0,40 - 0,47 for MBDU), and ODI indices were higher in the SSFD group in all follow-ups (p = <0.001). During the follow-up period, symptomatic ASD was observed in 3 of 47 patients in the SSFD group, whereas no symptomatic ASD was observed in the MBDU group. In selected patients who develop ASD after fusion surgery MBDU after instrumentation removal can be considered as a minimally invasive option that does not exacerbate postoperative lumbar pain syndrome or lead to the development of new ASD. To the best of our knowledge, this is the first comparison of these two techniques in literature after removal of spinal fixators in lumbar ASD cases.