Failed lumbar spinal surgery

Clinical outcomes after microendoscopic discectomy for recurrent lumbar disc herniation

STUDY DESIGN

Retrospective review of consecutive case series.

OBJECTIVE

To assess the safety and efficacy of the microendoscopic approach for treatment of recurrent lumbar disc herniation.

SUMMARY OF BACKGROUND DATA

The standard surgical approach for the treatment of recurrent disc herniation uses an open technique with a wide exposure. Many would consider a minimally invasive approach such as microendoscopic discectomy (MED) to be contraindicated in the setting of recurrent disc herniation.

METHODS

Sixteen consecutive patients with recurrent lumbar disc herniation who failed conservative management underwent MED. Before surgery and at follow-up, patients completed the Oswestry Disability Index, SF-36, and assessment of leg pain using the Visual Analog Scale. Outcome was also assessed using modified McNab criteria.

RESULTS

No case required conversion to an open procedure. Mean operative time was 108 minutes, and mean estimated blood loss was 32 mL. The only surgical complications were 2 durotomies that were treated with dural sealant without sequelae. Mean hospital stay was 23 hours, and mean follow-up was 14.7 months. Approximately 80% of patients had good or excellent outcomes based on modified McNab criteria. The remaining 3 patients had fair outcomes, and no patient had a poor outcome. All standardized measures improved significantly, including mean Visual Analog Scale for leg pain (8.2 to 2.2, P<0.001), mean Oswestry Disability Index (59.3 to 26.7, P<0.001), SF-36 Physical Component Summary score (28.3 to 42.4, P<0.001), and SF-36 Mental Component Summary score (38.2 to 48.3, P<0.001). As of last follow-up no patient has showed recurrence of herniation or evidence of delayed instability.

CONCLUSIONS

MED is a safe and effective surgical approach for the treatment of recurrent lumbar disc herniation. Standardized measures of outcome show that MED for recurrent herniation produces improvement in pain, disability, and functional health that is at least comparable with outcomes reported for conventional open microdiscectomy.

Failed back surgery syndrome: diagnostic evaluation

Failed back surgery syndrome is a common problem with enormous costs to patients, insurers, and society. The etiology of failed back surgery can be poor patient selection, incorrect diagnosis, suboptimal selection of surgery, poor technique, failure to achieve surgical goals, and/or recurrent pathology. Successful intervention in this difficult patient population requires a detailed history, precise physical examination, and carefully chosen diagnostic tests. The diagnostic evaluation should endeavor to accurately identify symptoms, rule out extraspinal causes, identify a specific spinal etiology, and assess the psychological state of the patient. Only after these factors have been assessed can further treatment be planned.

Microendoscopic discectomy for recurrent disc herniations

OBJECT

The use of microendoscopic discectomy (MED) for the treatment of primary lumbar disc herniations has become fairly well accepted; its role in recurrent disc herniations is less clear. The reluctance of many surgeons to use this technique stems, in part, from the concern of undertaking an endoscopic discectomy in a patient in whom the anatomy is distorted from a previous operation. It appears counterintuitive to operate through a limited working area when the traditional open approach for recurrence favors wider exposure of the surgical field. Given that operating on previously exposed tissue can be associated with even greater morbidity than on virginal tissue, the authors describe their experience with performing MED for recurrent disc herniation.

METHODS

Unilateral MED was performed in patients with classic symptoms of lumbar radiculopathy, a previous operation at that level, and findings of recurrent disc herniation on magnetic resonance imaging. The approach was similar to a standard MED. Aided by fluoroscopic guidance, a working cannula was docked on the laminofacet junction at the level of the nerve root, with care taken to ensure a slightly more lateral initial trajectory. A good decompression of the nerve root could then be achieved through the use of the endoscope with preservation of the paraspinous musculature and much of the remaining facet capsule. Ten consecutive patients undergoing the procedure were analyzed prospectively and compared with the previous 25 who underwent routine single-level MED. Use of the MED technique provided excellent visualization and decompression of the nerve root; no conversions to open procedures were necessary in either group. The average operative time in the experimental group was 98.5 minutes, with a mean blood loss of 33 ml and an approximate hospital stay of 7.3 hours. In this respect, there was no statistical difference between the two groups (analysis of variance, p = 0.39, 0.68, and 0.51, respectively). There was one cerebrospinal fluid leak in each group.

CONCLUSIONS

Microendoscopic discectomy for recurrent disc herniation can be safely performed without an increase in surgery related morbidity.