Percutaneous Endoscopic Decompression in Lumbar Canal and Lateral Recess Stenosis - The Surgical Learning Curve

Abstract

Objective: The purpose of this study is to characterize the learning curve of endoscopic lumbar decompression based on peri- and postoperative parameters and to suggest the potential of full endoscopic decompression as a primary treatment option for lumbar canal and lateral recess stenosis.

Methods: The records of 223 consecutive patients who underwent percutaneous endoscopic decompression by a single surgeon for their lumbar canal and lateral recess stenosis were reviewed. Patients were stratified into group 1 (n=100) and group 2 (n=123), depending on their case number. After the 100th case, the procedural time reached a plateau and subsequent patients were assigned to the second group. Demographics and surgical outcomes, including operative times, change in dural sac dimensions, length of hospital stay, and intraoperative complication rates were compared between the 2 groups. Postoperative clinical outcomes, including the visual analogue scale (VAS), the Oswestry Disability Index (ODI) and reoperation rates were compared between the 2 groups (group 1, n=90; group 2, n=110) by follow-up evaluation.

Results: Procedural times were greater in group 1 than group 2 (group 1, 105.26 minutes; group 2, 67.65 minutes; p<0.05) and they had higher complication rates (group 1, 16% [16 of 100]; group 2, 8.3% [8 of 123]; p<0.05). The length of hospitalization, postoperative improvement in VAS and ODI, and reoperation rates were not different between the groups. In both groups, stenotic spinal canals were effectively decompressed.

Conclusion: Continued surgical experience was associated with a reduction in operative times and less intraoperative complications. Although the learning curve was steep and additional surgical experience may be needed to overcome the learning curve, percutaneous full endoscopic lumbar decompression is a safe, clinically-feasible, and effective surgical technique and can be adopted as the primary treatment for lumbar canal and lateral recess stenosis.

Keywords: Learning curve; Lumbar canal decompression; Percutaneous endoscopic.

Fig. 1.

Flowchart of patient inclusion, exclusion, and postoperative outcome evaluation. VAS, visual analogue scale; ODI, Oswestry Disability Index.

Fig. 2.

(A-C) Operative illustration of endoscopic intraoperative findings showing decompressed thecal sac, ipsilateral, and contralateral traversing root (asterisk). (D-G) Anatomical landmarks in percutaneous endoscopic lumbar canal decompression showing ligament flavum (asterisk), midline (red dotted line), medial margin of the ipsilateral superior articular process (SAP) (black dotted curved line), and medial margin of the contralateral SAP (white dotted curved line).

Fig. 3.

Graph of the learning curve based on operation time (A) and length of hospitalization (B) plotted against case number.

Fig. 4.

Changes in the visual analogue scale (VAS) (A) and Oswestry Disability Index (ODI) (B) improvement.