INTRODUCTION:

Central lumbar disc nucleotomy is a simple technique that has been reported to have widely varying success rates. Our hypothesis was that moving posteriorly to get to the actual location of a disc herniation and removing the core of it would be more consistently effective. The purpose of this study was to conduct a long term, retrospective analysis of all patients that were treated with an outpatient endoscopic, posterior intradiscal placement procedure at L4-5 or L5-S1 in the past 6 years, using a straight cannula of approximately 4 mm in outer diameter. A pre-operative lateral decubitus abdominal view ct scan, symptomatic side up, was done in all cases; to be sure of the safety of the access pathway. Assume that a 45 degree angle postero-lateral approach from the skin surface would bring the intradiscal access into the center of the disc. Then using a straight cannula, and moving the skin opening more lateral from the spine, results in a more posterior position inside the disc. These procedures were done this way, manually using endoscopic visualization. A single approach without any bone or joint removal was used, with only local anesthetic and IV sedation.

MATERIALS AND METHODS

Back Institute is a private patient care and physician educational institution, where physicians have been, and are, trained to perform cervical and lumbar endoscopic procedures. Back Institute has had neurosurgeons, orthopedic and pain management physicians, performing these posterior placement procedures in this study. It has clinics in NYC and Los Angeles and licensed ambulatory surgery centers in CA and PA.
At the time of the procedure, the proper consents were signed by all patients.
29 patients were available for follow-up, an average of 3.2 years after their procedures. All patients had contained herniations, either central or postero-lateral protruding into the spinal canal, producing radiculopathy. 7 females and 22 males, ranging in age from 30 to 89, average age 58 years, were evaluated. Patients with previous surgery were excluded. Also, patients with multiple level problems were excluded.
This study is exempt from IRB review requirements, as per BI policy, since it is devoid of patient identifiable information, and since the study was a retrospective one and did not conduct systematic investigation involving a prospective plan for the patients whose records were reviewed.
As per Back Institute policy, all results were peer reviewed and results were reported to the MAB (Medical Advisory Board), which meets quarterly and reviews all cases from the quarter. All recommendations, and approval or disapproval, were provided to the governing body of Back Institute.

RESULTS

The Oswestry Low Back Pain Questionnaire was used prior to surgery and at the final follow-up. The mean preoperative ODI was 55.8% and finally, at last follow-up 5.6%. MacNab criteria, at last follow-up, showed: 10 G (good) and 19 E (excellent). There were no fair and/or poor long term results indicating that these procedures were successful long term. There were no complications. No patient had surgery subsequently (no recurrences)

DISCUSSION

Larger scopes, than these, do allow for bone removal, but they inherently have greater risk of nerve, joint or dural injury. With the above approach, since no bone or joint is removed, and there is a lack of the usual spine surgery scarring, the negative sequelae associated with these aspects are not a concern. If a lumbar MRI needs to be done in the future, no contrast should be needed, since the procedures described above typically do not produce scarring. Anatomically it is valid that the lateral access used in this study would not be affected by spinal canal scarring.

Conclusions:

1) The approach used in this study can be performed by a wide range of specialists. If a doctor can do a central disc decompression, the doctor should be able to do these procedures.
2) In the above group a single approach, posterior placement was found to be consistently effective, as per our hypothesis, in contrast with proviously reported central nucleotomy results
3) Larger operations, than these, may create pathway cicatrix, and eliminate the possibility of a future endoscopic procedure done directly through scar. However, the access positioning described above (posterior intradiscal placement reached from a lateral access) could still be done, since it would usually not be directly through scar.Typical spine surgery is known to cause scarring inside the spinal canal.