A meta-analysis of interlaminar minimally invasive discectomy compared to conventional microdiscectomy for lumbar disk herniation

• ILMI and MD are both safe and effective surgical procedures for treating LDH.
• Compared with MD, ILMI can shorten days in hospital, decrease the mounts of blood loss during surgery.
• The current GRADE evidence quality was very low.

A meta-analysis was conducted to evaluate the evidence that compared the safety and efficacy of interlaminar minimally invasive discectomy (ILMI) and conventional microdiscectomy (MD) for treating lumbar disk herniation (LDH) patients and to develop GRADE based recommendations for using the procedures to treat LDH. Eleven studies, encompassing 1012 patients, met the inclusion criteria. Overall, the results of the meta-analysis indicated that there were significant differences between the two groups in blood loss (SMD = −0.93, 95% CI −1.84, −0.02; p = 0.05), and the number of days stays in hospital (SMD = −0.79, 95% CI −1.55, −0.04; p = 0.04). However, there were no significant differences in the short-term back visual analog scale (VAS) scores (SMD = −0.34, 95% CI −0.81, 0.14; p = 0.16), the long-term back VAS scores (SMD = 0.13, 95% CI −0.04, 0.30; p = 0.14), the short-term leg VAS scores (SMD = 0.14, 95% CI −0.01, 0.29; p = 0.07), the long-term leg VAS scores (SMD = 0.12, 95% CI −0.05, 0.30; p = 0.17), the short-term Oswestry disability index (ODI) scores (SMD = 0.01, 95% CI −0.14, 0.15; p = 0.92), the long-term ODI scores (SMD = 0.11, 95% CI −0.03, 0.25; p = 0.14), and the incidence of complications (RR = 1.22, 95% CI 0.88, 1.69; p = 0.24). The results of this meta-analysis demonstrate that ILMI and MD are both safe and effective surgical procedures for treating LDH. Compared with MD, ILMI can shorten days in hospital, decrease the mounts of blood loss during surgery. However, the overall GRADE evidence quality was very low. Therefore, further validation is required, and medical institutions should conduct high-quality studies.