The translaminar approach to canalicular and cranio-dorsolateral lumbar disc herniations

The interlaminar approach is the standard procedure for most disc herniations in lumbar spine surgery. However, in cranially extruded disc herniations including canalicular herniations, partial or complete facetectomy is necessary with increased risk of postoperative spinal instability. We present the translaminar technique which allows a more direct and less destructive operative approach.

30 patients using the translaminar fenestration were analysed by a postoperative follow-up of 6 weeks and one year. The mean-age was 57.2 years. For resection of the disc herniation, a small round or oval fenestration (6-8 mm) in the hemilamina, craniomedially to the facet joint, was performed. No patient received a partial or total facetectomy.

The majority of affected discs were at the L4-L5 level (53%). An extruded fragment was found in 28 patients (93%). In 5 patients bleeding from epidural veins complicated the intra-operative course. In 50% the nerve root was visually exposed. 15 patients (50%) had an intervertebral discectomy additional to the fragment excision. One patient was re-operated on after 10 days because of persisting radicular pain by using the same translaminar approach. 28 patients showed complete or nearly complete relief of radicular pain. Using this approach we have seen no major complication or clinical instability during a follow-up of at least one year.

The translaminar approach is an effective and minimally invasive technique in both canalicular and cranio-dorsolateral disc herniations. It gives an additional possibility to avoid partial removal of the facet joints, can be performed in all lumbar segments and preserves structures important for segmental spinal stability. The approach allows access to the extruded disc fragment and intervertebral disc space comparable to classical approaches and is a frequently used operative technique in our department.