Endoscopic Anterior Cervical Decompression And Fusion

Although during the past several decades traditional anterior cervical decompressin and fusion for cervical disc disease has widely been used by orthopedist and neurosurgeon, complications related to the operation were reported from time to time. The recurrent laryngeal nerve and esophagus can occasionally be injured in this procedure. Because of the poor lighting of the operation field, some indistinction inhered in the procedure can resulted in the cervical cord injury. The relatively long incision can also cause cosmetic problem. The recent success of using microendoscope in the thoracic and lumbar spine and preliminary successful experience reported in the literature about endoscopic anterior cervical discectomy stimulated our efforts to conduct this study. After successful operation on cadaveric model, we cautiously applied the technique in patients with cervical spondylosis. We modified some instruments for the procedure. A very good clinical result was obtained.Part I Endoscopic anterior approach and decompression technique: a cadaveric model studyObjectives: To study the feasibility and technique of endoscopic anterior approach and decompression and the necessity of this technique on the operative instruments. Methods: With the Metrx MED system, we performed 10 endoscopic anterior cervical discectomy on the C3-7 cervical spine of 5 cadaveric specimens. A 2cm paramidline right incision was made and a working tube of 18mm outer diameter was inserted through the space between the neurovascular sheath laterally and the visceral sheath medially and fixed to the operating table through a flexible arm. Then the endoscope was mounted to the working tube. Discectomy and curettement of posterior vertebral osteophyte was made under the help of the endoscope. Results: No injury of important soft tissue structure surrounding the approach was founded. Whether a trepan was used or not, material of all of the 10 intervertebral disc was removed satisfactorily. Manipulation with pituitary rongeur or curette for the remove of the posterior vertebral osteophte was limited by the too long working tube. In the group a trepan was used, 3 of the posterior vertebral osteophte founded at autopsy were curetted off for some extent, anther 3 were leaved intact. In the group only the pituitary rongeur and curette were used, 3 of the osteophyte were curetted off for some extent, 5 were found in good condition. No injury to the duro sac was noted in the procedure. Conclusion: endoscopic anterior cervical decompression isfeasible. Some modification of the instruments should be made for clinical application.Part II Endoscopic anterior cervical decompression and fusion based on the use of a working tube.Objectives: To investigate feasibility and efficacy of clinical application of endoscopic anterior cervical decompression and fusion. Methods: With Metrx MED system and modified working tube and decompression instruments, endoscopic anterior cervical decompression and fusion was performed on 12 patients with cervical spondylotic myelopathy. A paramidline right transverse incision of 2-2.5cm long was made. A channel between the neurovascular and visceral sheath was created through finger dissection. The dilators were inserted sequentially. A original 18mm outer diameter working tube or a shortened 16mm outer diameter working tube with double arms was inserted over the dilators. After the working tube was fixed with one or two flexible arms, decompression and fusion with autologus graft was performed under endoscope. Results: Shortened working tube provided improved visual field and increased manipulation space for the decompression instrument. The double arms enhanced stability of the working tube but could not eliminate moving of it during operation. At the end of the follow-up, greater than 80% of the preoperatively lost spinal cord function wasregained postoperatively in 6 of the 12 patients and greater than 60% of the lost spinal cord function was regained postoperatively in 11 of the 12 patient...