184 - Intradiscal Therapy for Discogenic Low Back Pain...

#184 Intradiscal Therapy for Discogenic Low Back Pain

MIS Techniques and Outcomes

Poster Presented by: A.T. Yeung

Author(s):

A.T. Yeung (1,2)

(1) Desert Institute for Spine Care, Phoenix, AZ, United States
(2) University of New Mexico School of Medicine, Aalbuquerque, NM, United States

Abstract

Introduction: Non-operative therapeutic regimens often fail to achieve effective relief in chronic discogenic back pain. Surgical options range from intradiscal electrothermal therapy to lumbar fusion. Endoscopic techniques in the literature feature visualized intradiscal procedures that incorporate selective endoscopic discectomy with thermal annuloplasty for discogenic back pain.

Study Design and setting: A 1997 IRB approved study of endoscopic spine surgery for painful degenerative conditions of the lumbar spine determined that KTP laser as well as radiofrequency annular thermal modulation can provide back pain relief emanating from the lumbar disc. The clinical outcome of a retrospective study of 113 consecutive patients with minimal 2 year follow-up was reported in Spine, October 2004. Outcome measurements were by modified MacNab surgeon rating and a patient questionnaire. Patient selection included positive evocative discography pre-operatively and/or intraoperatively, correlated with an abnormal discogram pattern. At surgery, chromo-discography with diluted indigo carmine dye stained the degenerative nucleus pulposus blue, targeting the blue stained degenerative tissue for endoscopic removal. Tears in the annulus had interposed disc material in the annlus, preventing it from healing.The annulus was the treated by laser and radiofrequency flex probes under endoscopic visualization. Interpositional nucleus material embedded in the annulus needed to be removed for best results.

Findings: The painful discs mostly had inflammatory or granuation tissue associated with annular tears. The degenerative nucleus pulposus is removed mechanically with pituitary rongeurs and shavers, then the granulation and inflammatory tissue send adjacent to the annular tears are thermally modulated by flexible radiofrequency electrodes. The annular defects are endoscopically observed to be altered by radiofrequency treatment.

Results: A wide spectrum of degenerative discs form early to late stage degenerative disc disease were treated. Eighty-three patients 83/113 (73.5%) were in the satisfactory outcome group. This group of patients included excellent, good, and fair categories. Excellent outcome was reported in seventeen patients (15%); good in thirty-two patients (28.3%); and fair in thirty-four (30.1%). Thirty patients (26.5%) were determined to have poor results. The specific reasons were as follows: twelve patients were not improved after the endoscopic surgery, eight patients had subsequent lumbar fusion; seven patients had repeat lumbar endoscopic surgery; and three patients had lumbar laminectomy. Twelve patients in the poor category elected to have no further back surgery. Of the eighteen patients who had secondary back surgery, ten reported improvement after the subsequent operation. The satisfied group of patients would select the lumbar endoscopic surgery again in the future given the knowledge gained from their endoscopic experience. Experience gained from this study led to more stringent patient selection criteria.

Discussion: From this early experience with Selective endoscopic discectomy, a less invasive 3mm fluoroscopically guided cannula was developed combining mechanical discectomy with thermal annuloplasty. The results mirrored visualized endoscopic discectomy and thermal annuloplasty. This fluoroscopically guided system is presented here.

Conclusion: The treatment rationale for selective endoscopic discectomy and thermal annuloplasty includes endoscopic discectomy to decompress the disc and to remove the source of chemical sciatica from the deteriorating nucleus, but also removes the nuclear tissue embedded in the annular tear. Inflammatory tissue is thermally ablated. Case examples will illustrate the patho-anatomy and its reaction to thermal annuloplasty.