Comparison of Percutaneous Endoscopic Transforaminal and Interlaminar Approaches in Treating Adjacent Segment Disease Following Lumbar Decompression Surgery: A Clinical Retrospective Study.

Background: Adjacent segment disease (ASD) is a common complication following posterior disc decompression and fusion surgery. Percutaneous endoscopic lumbar decompression surgery (PELD) has been used to treat ASD through either a transforaminal or interlaminar approach. However, to our limited knowledge there are no reports comparing the 2 approaches for treating ASD.

Objective: To evaluate clinical outcomes of PELD in treating ASD and comparing the surgical results and complications between the 2 approaches. This may be helpful for spinal surgeons when decision-making ASD treatment.

Study Design: A clinical retrospective study.

Setting: This study was conducted at the Department of Orthopedics of the Affiliated Hospital of Qingdao University.

Methods: From January 2015 through December 2019, a total of 68 patients with ASD who underwent PELD after lumbar posterior decompression with fusion surgery were included in this study. The patients were divided into a percutaneous endoscopic transforaminal decompression (PETD) group and a percutaneous endoscopic interlaminar decompression (PEID) group according to the approach used. The demographic characteristics, radiographic and clinical outcomes, and complications were recorded in both groups through a chart review.

Results: Of the 68 patients, 40 underwent PEID and 28 patients underwent PETD. Compared with their preoperative Visual Analog Scale (VAS) pain score and Oswestry Disability Index (ODI) score, all patients had significant postoperative improvement at 3 months, 6 months, one year and at the latest follow-up. There were no significant statistical differences in the VAS and ODI scores between PETD and PEID groups with a P value > 0.05. There was a significant statistical difference in the average fluoroscopy times between the PETD and PEID groups with a P value = 0.000. Revision surgery occurred in 8 patients: 6 patients who underwent PETD and 2 patients who underwent PEID. The revision rate showed a significant statistical difference between the 2 approaches with a P value = 0.039.

Limitations: Firstly, the number of patients included in this study was small. More patients are needed in a further study. Secondly, the follow-up time was limited in this study. There is still no conclusion about whether the primary decompression with instruments will increase the reoperation rate after a PELD, and a longer follow-up is needed in the future. Thirdly, this study was a clinical retrospective study. Randomized or controlled trials are needed in the future in order to achieve a higher level of evidence. Fourthly, there were debates about PELD approach choices for ASDs, which may affect the comparison results between PETD and PEID. In our study, the approaches were mainly determined by the level and types of disc herniation, and the surgeons' preference. More patients with an ASD with different levels and types of disc herniation and surgical approaches are needed in the future to eliminate these biases.

Conclusion: Percutaneous endoscopic lumbar decompression surgery is a feasible option for ASD following lumbar decompression surgery with instruments. Compared with PETD, PEID seems to be a better approach to treat symptomatic ASDs.