"Tube in tube" interlaminar endoscopic decompression for the treatment of lumbar spinal stenosis: Technique notes and preliminary clinical outcomes of case series.

To describe the Tube in Tube interlaminar endoscopic decompression method and investigate its efficacy and safety in treating lumbar spinal stenosis (LSS).Utilizing the advantages of the micro-endoscopic decompression (MED) operation channel tube, we used a water-medium spinal endoscopy to perform trans-interlaminar canal decompression, that is, the "Tube in Tube" technique. A retrospective study was performed on 35 patients with LSS who were treated with the Tube in Tube technique. All patients were followed up to 12 months postoperatively. Visual analog scale (VAS), Japanese Orthopaedic Association (JOA) score, and Oswestry Disability Index (ODI) were collected preoperatively and at 3, 6, and 12 months postoperatively. Short-form (36) health survey (SF-36) score was used to examine the general health-related quality of life (HRQoL) of patients preoperatively and at 3 and 12 months postoperatively. Modified Macnab criteria were used to examine the clinical outcomes at 3 and 12 months post-surgery.The clinical outcomes were satisfactory, with an improvement in all scoring systems. The VAS, JOA, and ODI scores improved from 6.46 ± 1.85, 12.03 ± 4.96, and 42.17 ± 12.22 preoperatively to 2.20 ± 1.14, 21.40 ± 5.86, and 13.14 ± 7.52 at 12 months postoperatively, respectively (P < .001). The Macnab excellent or good rates reached 65.7% and 77.1% at the 3 and 12 months follow-ups. No severe complications occurred.The Tube in Tube technique had a positive clinical outcome in LSS patients and is safe, reliable, and efficacious. However, a larger number of cases and a multi-center research design will be needed further develop the technique.Level of Evidence: IV.