Minimally invasive spine surgery has been developed in an effort to afford patients the benefits of open spine surgery without the morbidity caused by the exposure of the spine. While most papers have focused on less invasive lumbar surgery, interest in minimally invasive cervical spine surgery has also developed. In the November 15 issue, Dr. Solimon reports his results from a small RCT comparing traditional ACDF to a microendoscopic version of the procedure. Seventy patients with cervical radiculopathy and/or myelopathy were randomized to either open ACDF or a less invasive procedure performed through a tubular retractor. Patients were included if they had one, two or three level disease with pathology that could be addressed through discectomy (patients requiring corpectomy were excluded). After performing the decompression, PEEK cages packed with iliac crest autograft were placed in the disk spaces, and no anterior plates were placed. Patients were blinded until the bandage was removed on post-operative day 10, and outcome assessors remained blinded throughout the study. The endoscopic surgery took about 8 minutes longer than the open procedure, though operative time was relatively short at approximately one hour. The endoscopic patients were typically discharged in about one day while the open patients tended to stay hospitalized for two days. The endoscopic patients reported less dysphagia than the open patients and also reportedly used less pain medication post-operatively. At a mean follow-up of 28 months, clinical outcomes on the Japanese Orthopaedic Association score and VAS neck and arm pain scales were similar for the two groups. The authors reported only one case of pseudarthrosis, which was in the endoscopic group.
Based on the data reported, it seems as though endoscopic ACDF may yield some short term benefits in terms of shorter hospital stays, less need for analgesics, and less dysphagia compared to the open procedure. Longer term clinical outcomes and fusion rates were similar for the two procedures, suggesting that the short term benefits of the endoscopic procedure did not come at the price of compromised long term outcomes. Whereas less invasive techniques in the lumbar spine typically use muscle splitting rather than muscle stripping techniques, the endoscopic technique in the anterior approach to the cervical spine is nearly identical to the open technique with the exception that it is performed using a smaller incision. It is unclear if simply using a smaller incision should have as much of an effect on short term outcomes as noted in this paper, however, avoiding the use of a self-retaining retractor that generates a fair amount of force on the soft-tissues may be the more important factor. One surprising aspect of this paper is that only one pseudarthrosis was reported out of 70 cases, and the fusion rate for multilevel procedures—which made up the majority of cases in this study—has typically been reported as substantially lower than that recorded in the current study, especially if a plate is not used. The authors noted that plating through the tubular retractor is not feasible, which is another drawback to the procedure. The current paper indicates that uninstrumented ACDF can be performed through a tubular retractor system, and it may be associated with some short term benefits. However, many surgeons prefer to make use of an anterior plate, so this technology may be adopted slowly if at all.
Please read Dr. Solimon’s article on this topic. Will you adopt this technique for your cervical patients? Let us know by leaving a comment on The Spine Blog.
Adam Pearson, MD, MS
Associate Web Editor