Efficacy of Percutaneous Spinal Endoscopic YESS Technique in Adjacent Segmental Disease Without Severe Instability After Lumbar Fusion Surgery: A Case Series.

Abstract

Background: The adjacent segment disease (ASD) after lumbar fusion is inherently stressed abnormally, and the destruction of bony structures in surgery can further exacerbate that abnormality. The Yeung Endoscopic Spine Surgery (YESS) technique does not destroy facet joints, and therefore it may be a good indication for ASD. However, the efficacy of the YESS technique in ASD patients have not been reported.

Patients and methods: From January 2018 to May 2023, 13 patients with adjacent spondylolisthesis secondary to lumbar fusion were treated with endoscopic YESS technique surgery. Patients' visual analog score (VAS) and Oswestry disability index (ODI) score were analyzed preoperatively, 3 days postoperatively, and at the final follow-up. Gait analysis parameters and intervertebral height index of patients preoperatively and at 1 year postoperatively were used to objectively quantify patient pain, function, and radiographic changes.

Results: A total of 13 patients, 2 females and 11 males, had single-segment adjacent spondylolisthesis. The patients' VAS and ODI scores at 3 days postoperatively decreased (P<0.05) compared to preoperatively and further decreased (P<0.05) at the final follow-up. There were no infections, wound complications or reoperations. The results of gait analysis showed no statistically significant difference in single-stance time and the gait cycle before and after the patients' surgery (P>0.05), but the patients' velocity, step length, step time, step frequency and stride length were significantly improved at 1-year postoperatively (P<0.05). Intervertebral height loss did not occur in all patients.

Conclusion: In the short term, spinal endoscopic YESS technique markedly improves clinical symptoms and gait parameters in patients with ASD without severe instability after lumbar fusion, while avoiding facet joint destruction and intervertebral height loss. Future studies with larger sample sizes and longer follow-up times are needed to clarify the long-term efficacy.