Clinical report of revision surgery after percutaneous transforaminal endoscopic surgery for lumbar stenosis

Objective To analyze the causes of revision surgery after percutaneous transforaminal endoscopic discectomy (PTED) for lumbar spinal stenosis, and to provide references for indications and operative methods. Methods From January 2015 to October 2017, 206, 491 and 60 patients of lumbar spinal stenosis were treated with PTED in Tianjin Hospital, Shanxi People's Hospital, Ningbo Sixth Hospital, respectively; among them, 4, 10 and 4 cases received revision surgery. Another 13 patients of lumbar spinal stenosis were treated with revision surgery due to poor results after PTED in other hospitals. Among 31 cases of reoperation, there were 16 males and 15 females, aged 27-82 years (average, 66.2±12.7 years). The lesion segments included 1 case of L3,4, 23 cases of L4,5, 5 cases of L 5S1, 1 cases of L 3-L5, and 1 cases of L 4-S1. Patients were followed up after reoperation from 3 to 24 months (average, 12.1 months). The causes of poor result and revision surgery were analyzed according to preoperative, intra-operative and postoperative data. Results All of 757 cases of lumbar spinal stenosis were treated with PTED in three hospitals, of which 18 cases (2.4%) were re-operated. The causes of reoperation included: bone slice displacement in 1 case; nerve injury in 4 cases; lumbar instability in 4 cases; disc protrusion in 10 cases (residual or recurrence); insufficient decompression in 21 cases; planed staging operation in 4 cases with bilateral or two-level stenosis. 32 revision surgeries were performed for 31 patients, including PTED in 15 cases, microendoscopic discectomy (MED) in 1 case, mobile MED (MMED) in 5 cases, MMED assisted fusion in 2 cases, transforaminal lumbar interbody fusion (TLIF) in 4 cases, Minimally invasive TLIF (Mis-TLIF) in 2 cases, and open decompression and fusion in 3 cases. All patients experienced relieve of symptoms after revision surgery. At final follow-up, VAS leg pain deceased form 7.1±3.9 before revision surgeries to 1.9±1.2, VAS low back pain decreased form 6.3±3.2 to 1.8±1.3, ODI score decreased from 35%±14% to 7.6%±5%. According to the MacNab score, the result was excellent in 11 cases, good in 16 cases, and fair in 4 cases. Conclusion The treatment of lumbar stenosis with PTED has high technical requirements, the indications of PTED for lumbar stenosis should be strictly controlled according to technical conditions, and appropriate operative methods should be chosen according to the specific conditions of the lesions. Insufficient decompression, disc protrusion, lumbar instability and nerve injury are the common causes of reoperation. Suitable indications and proper operation should be selected. Key words: Lumbar vertebrae; stenosis; Endoscopy; Surgical procedures; Outcome