Microendoscopic Disectomy for Recurrent Disc Herniations

Robert E. Isaacs, M.D.; Vinod Podichetty, M.D., M.S.; Richard G. Fessler, M.D., Ph.D.


Neurosurg Focus. 2003;15(3) 

In This Article

Abstract and Introduction

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.

Recurrent lumbar disc disease (reherniation on the same side and at the same level where a previous discectomy had been performed) can present a formidable challenge in the treatment of patients with radiculopathy. Initially, there exists a diagnostic challenge, differentiating disc material from residual bone hypertrophy and epidural scar formation. Secondarily, there is a therapeutic dilemma. Failure to relieve stenosis (along with operating at the incorrect level) is one of most preventable causes for failed-back syndrome;[3,17] however, this must be weighed against the fact that reoperation carries with it a higher rate of complications and a lower rate of success.[25] Finally, there is a progressively larger group of patients whose condition worsens following each operation, and the long-term success rate tends to drop in those patients who undergo multiple operations at the same level in the lumbar spine.[2,4,10,11,12,15,17,25,27] Clearly, careful patient selection is of paramount importance in determining a candidate for reoperation (Fig. 1).

Axial contrast-enhanced magnetic resonance image obtained in a patient with recurrent disc herniation at L5-S1 prior to undergoing removal by a MED.

The standard surgical technique for recurrence utilizes a more extensive tissue dissection to aid with exposure.[13] Increased visualization facilitates tissue manipulation and increases the surgeon's understanding of the exposed anatomy. For this reason, despite acceptance of the MED technique, previous surgery in the same anatomical distribution is considered a contraindication to MED.[6] The increased morbidity associated with repeated surgery may be partially related to operating in an area without smooth tissue planes and with distorted anatomy. This is known to increase the risks of surgery[5,18,19,20,21,22] as well as postoperative pain. It is understandable given this distortion of anatomy and increased risks that one would want to maximize the area seen, not limit it as one does when working with an endoscope. Despite that, once comfortable with the use of an endoscope, we do not believe that we are "limited." By way of example, we present our experience in reoperation using the MED technique.