17 - A comparative study of bilateral access by PETD with unilateral access bilateral decompression by large channel endoscopy for severe central lumbar spinal stenosis

Objective To compare the efficacy of bilateral decompression by percutaneous endoscopic transforaminal discectomy with unilateral interlaminar approach with large channel endoscopic in the treatment of severe central lumbar spinal stenosis to further provide references for the selection of surgical methods. Methods A total of 81 patients with single-segment severe central lumbar spinal stenosis and bilateral lower extremity symptoms endoscopically treated at our hospital were retrospectively analyzed from February 2017 to May 2020. Among them, 31 cases were treated with bilateral decompression by large channel endoscopy with unilateral access ( group A ), and the other 50 cases were treated with bilateral decompression by percutaneous endoscopic transforaminal discectomy ( 7 mm ) ( group B ). The gender composition ratio, age, duration of surgical decompression, intraoperative C-arm fluoroscopy frequency, postoperative hospital stay, surgical outcome and complications were compared between the two groups. Visual analog scale ( VAS ) was used for lower extremity pain assessment before surgery, 1 month after surgery and at the final follow-up. Oswestry Disability Index ( ODI ) was evaluated before surgery, 1 month after surgery and at the final follow-up. Surgical efficacy was assessed at the final follow-up according to the modified MacNab scale. Results All 81 surgeries were completed successfully without nerve injury, mid-transfer opening or intervertebral space infection. One case in group A and two cases in group B developed aggravated postoperative lower limb numbness. Dural sac tear was observed in 1 case of group B. All patients were followed up for 13 - 25 months after surgery, with a mean of ( 19.1 ± 3.9 ) months. Differences in gender, age, preoperative VAS, ODI and follow-up time between the two groups were not statistically significant ( P > 0.05 ). Differences in operation time [ ( 84.5 ± 18.5 ) mins vs. ( 106.2 ± 12.7 ) mins, P = 0.000 ] and intraoperative C-arm fluoroscopy frequency [ ( 7.4 ± 1.9 ) vs. ( 20.9 ± 4.4 ), P = 0.000 ] between group A and B were statistically significant. The VAS and ODI were significantly lower in both groups 1 month after surgery and at the last follow-up compared with those before surgery ( P = 0.000 ). There were no statistical differences in the postoperative hospital stay between the two groups ( P = 0.168 ). According to the modified MacNab criteria: group A, excellent in 22 cases, good in 8 cases, fair in 1 case, with an excellent and good rate of 96.8%; group B, excellent in 35 cases, good in 13 cases, fair in 2 cases, with an excellent and good rate of 96.0%.
Conclusions Both bilateral percutaneous endoscopic transforaminal approach and unilateral interlaminar approach with large channel endoscopy are safe, effective and minimally invasive for the treatment of severe central lumbar spinal stenosis, and the clinical efficacy is similar. However, the use of unilateral interlaminar approach with large channel endoscopic bilateral decompression can significantly shorten the operation time and reduce intraoperative fluoroscopy frequency and surgical incisions.