Spine J 2004 Sep-Oct;4(5):564-73
1245 16th Street, #202, Santa Monica, CA 90404, USA.
Background Context: Chronic lumbar discogenic pain (CLDP) impairs the patient's physical abilities to function within the normal physiologic loading ranges of activities of daily living. The pathogenesis of CLDP is multifactorial and not well understood. Conservative therapeutic regimens often fail to achieve sufficient pain relief. Surgical options vary greatly in surgical invasiveness as well as outcome. Definitive surgical treatment is often 360-degree fusion. The morbidity associated with this approach is significant, considering that only 65% to 80% of patients obtain satisfactory clinical results. This has spawned interest in minimally invasive surgical options, such as intradiscal electrothermal therapy (IDET; ORATEC Interventions, Inc., Menlo Park, CA), but results are conflicting.
Purpose: The authors describe their surgical technique of minimal access posterolateral transforaminal selective endoscopic discectomy (SED) and bipolar radiofrequency thermal annuloplasty to treat CLDP. The procedure's rationale is based on the hypothesis that annular defects are the focal points of chronic exposure between neural sensory receptors in the defect and the inflammatogenic nucleus pulposus. In contrast to other percutaneous procedures, this technique allows direct visualization and targeting of the disc nucleus and annular fissures. Our 2-year clinical result is reported.
Study Design/setting: This is a retrospective review of consecutive surgical cases performed by one surgeon (ATY). The procedures were carried out from January 1997 to December 1999. Each patient has a minimum postoperative follow-up of 2 years.
Patient Sample: A total of 113 patients met the generally accepted clinical criteria for chronic lumbar discogenic pain and were selected for the procedure.
Outcome Measures: Two outcome measures were used for clinical assessment: a surgeon-based modified MacNab method and a patient-based questionnaire. A mandatory poor result was given to any patient who had repeat spine surgery at the same level or has indicated dissatisfaction with the surgical result on the questionnaire response.
Method: After meeting CLDP selection criteria, provocation contrast/indigo carmine dye discography was performed. This test was used to confirm the suspected discs as pain generators. The subject surgery then followed. Only cases with one and two levels of confirmed painful discs were entered into the study. The nonoperating author (PMT) analyzed the data.
Results: Using the surgeon assessment method, 17 patients (15%) had excellent results, 32 patients (28.3%) had good results, 34 patients (30.1%) had fair results and 30 patients (26.5%) had poor results. Of the 30 patients in the poor result group, 12 reported either no improvement or worsening, and refused further surgical treatment. Of the remaining 18 patients in the poor group, 8 had spinal fusion, 3 had laminectomy and 7 had repeat spinal endoscopic surgery. The patient-based questionnaire yielded similar percentages in each category. However, only 73.5% of the 113 patients returned the survey questionnaire. There were no aborted procedures, unexpected hemorrhage, device-related complications, neurologic deficits, perioperative deaths or late instability.
Conclusions: Posterolateral transforaminal SED and radiofrequency thermal annuloplasty were used to interrupt the purported annular defect pain sensitization process, thought to be necessary in the genesis of chronic lumbar discogenic pain. Lack of clinical benefit from the subject procedure did not degrade any subsequent surgical or nonsurgical treatment options. The experience gained from this study warrants further investigation into the cellular and molecular processes that provided back pain relief in these patients.