Microendoscopic discectomy for recurrent disc herniations

Abstract

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.