RADIOFREQUENCY FACILITATED MANUAL SEMI-ENDOSCOPIC DISCECTOMY UTILIZING THE DISC FX® SYSTEM IN THE TREATMENT OF DISC-PREDOMINATE LUMBAR SPINAL STENOSIS

Background: Lumbar spinal stenosis (LSS) occurs with increasing prevalence in the elderly population. The American Academy of Orthopedic Surgeons has estimated that by 2021, 2.4 million adults in the United States (8-11% of the population) will be affected by this condition. Surgical options for LSS are being performed with increased frequency, high cost, and substantial risk of life-threatening complications. While nonsurgical treatment options for LSS are available, they are limited by patient selection (ligamentum flavum hypertrophy) or high rates of reoperation (Interspinous process spacer devices). This study is the first to suggest a minimally invasive treatment option for disc-predominate lumbar central canal stenosis. Objectives: To evaluate the clinical efficacy of radiofrequency facilitated manual semi-endoscopic discectomy utilizing the Disc FX® system in the treatment of disc-predominate lumbar spinal stenosis. Study Design: Single center, prospective, observational study. Setting: Multi-specialty private practice clinic. The Medical Group of South Florida, Jupiter, FL. Methods: This study involved 6 patients with disc-predominant lumbar central spinal stenosis. All patients were treated with the Disc FX® system. Radiographic evidence of central lumbar stenosis was confirmed by measurement of minimum AP canal diameter (mm) performed by 1 board-certified neuroradiologist. Inclusion criteria included absence of lumbar surgery, physical therapy within the previous 6 months, failure of epidural steroid injections (3) within the previous 8 months, spondylolisthesis limited to Grade I, disc height > 50%, presence of low back axial pain + leg pain exacerbated by walking, and relieved with sitting or forward flexion, absence of dermatomal radicular leg pain, radiographic evidence of disc displacement > 4 mm from disc endplate. Zurich claudication (symptom severity and physical function scale was administered 1 week preoperatively, and again 6 months postoperatively. There were no patients lost to follow up. Results: All patients in the study demonstrated moderate-severe or severe central canal stenosis, with an average AP canal diameter of 6.63 mm for all treated disc levels and 5.5 mm for the most severe levels. There was a mean improvement of 57% in a symptom severity scale and 56% in the physical function scale at 6 months. This exceeds the improvement reported with interspinous spacer devices. Limitations: Limitations include very small sample size, observational design, non-randomization, absence of share controls, short follow-up period. Conclusion: For patients suffering from discpredominant lumbar spinal stenosis, The Disc FX® System provides an effective, low-cost alternative to surgical intervention. Key words: Spinal, stenosis, claudication, disc, Disc FX®, operative, minimally invasive, Zürich claudication score