Abstract: Abstract: Objective To evaluate the feasibility and clinical efficacy of microendoscopic discectomy- lumbar interbody fusion (MED-LIF) with mobile microendoscopic discectomy (MMED) technique. Methods The MMED includes outer working canal and inner operating canal, and large working canals (12 mm and 14 mm) are fabricated for this operation. The operation was designed as follow: an incision was made between pedicle projection sites and spinous process on the side with prominent symptom. Working canal was inserted along spinous process and a fenestration was performed. After discectomy and ipsilateral decompression, contralateral nerve was decompressed in case of contralateral stenosis. Then the intervertebral space was prepared and grafted. The inner operating canal was removed and the suitable cage was inserted, followed by percutaneous pedicles screws installation, reduction and fixation. A total of 102 patients with lumbar degenerative disc disease were treated by this technique. The index levels included L34 (n=11), L45 (n=64), L5S1 (n=21), L3-5 (n=3), and L4-S1(n=3). The operative data and follow-up results were recorded and evaluated. Results Surgery was successful in all patients, with no nerve injury or conversion to open surgery. The mean operative time was (120±30) min (range, 90-200 min), with a mean blood loss of (120±80) mL (range, 50-300 mL). The post-operative X-ray and CT scans showed improvement of spinal alignment with sufficient decompression. Patients were followed up for 6 to 36 months. The Oswestry disability index (ODI) score decreased from the pre-operative 44.2%±16.3% to the last follow-up 4.9%±4.7%. The visual analog pain score (VAS) of lumbar decreased from the pre-operative 5.3±4.1 to the last follow-up 2.1±1.7, and VAS of leg decreased from the pre-operative 6.7±3.5 to 1.0±0.8 at final follow-up. The clinical results were excellent in 46 cases, good in 50 cases and fair in 6 cases according to the Macnab standard. Conclusion MED-LIF can be easily performed with MMED technique, with sufficient decompression and reduction, providing satisfactory results with less invasive procedure.

Key words: lumbar vertebrae, intervertebral disk displacement, surgical procedures, minimally invasive, endoscopy