Rate of failure of indirect decompression in lateral single-position surgery: clinical results

Lateral single-position surgery (LSPS) of the lumbar spine generally involves anterior lumbar interbody fusion (ALIF) performed in the lateral position (LALIF) at L5-S1 with or without lateral lumbar interbody fusion (LLIF) at L4-5 and above, followed by bilateral pedicle screw fixation (PSF) without repositioning the patient. One obstacle to more widespread adoption of LSPS is the perceived need for direct decompression of the neural elements, which typically requires flipping the patient to the prone position. The purpose of this study was to examine the rate of failure of indirect decompression in a cohort of patients undergoing LSPS from L4 to S1.

A multicenter, post hoc analysis was undertaken from prospectively collected data of patients at 3 institutions who underwent LALIF at L5-S1 with or without LLIF at L4-5 with bilateral PSF in the lateral decubitus position between March 2018 and March 2020. Inclusion criteria were symptoms of radiculopathy or neurogenic claudication, central or foraminal stenosis (regardless of degree or etiology), and indication for interbody fusion at L5-S1 or L4-S1. Patients with back pain only; those who were younger than 18 years; those with tumor, trauma, or suspicion of infection; those needing revision surgery; and patients who required greater than 2 levels of fusion were excluded. Baseline patient demographic information and surgical data were collected and analyzed. The number of patients in whom indirect decompression failed was recorded and each individual case of failure was analyzed.

A total of 178 consecutive patients underwent LSPS during the time period (105 patients underwent LALIF at L5-S1 and 73 patients underwent LALIF at L5-S1 with LLIF at L4-5). The mean follow-up duration was 10.9 ± 6.5 months. Bilateral PSF was placed with the patient in the lateral decubitus position in 149 patients, and there were 29 stand-alone cases. The mean case time was 101.9 ± 41.5 minutes: 79.3 minutes for single-level cases and 134.5 minutes for 2-level cases. Three patients (1.7%) required reoperation for failure of indirect decompression.

The rate of failure of indirect decompression in LSPS from L4 to S1 is exceedingly low. This low risk of failure should be weighed against the risks associated with direct decompression as well as the risks of the extra operative time needed to perform this decompression.