To remove extruded disc fragments impinging the exiting root. To spare the interlaminar space and the facet joint.
Cranially migrated disc herniation.
Severe spinal canal stenosis.
Microscope from skin to skin, 25 mm skin incision about 5 mm off the midline, conventional subperiosteal route or transmuscular access by blunt splitting the multifidus muscle. A translaminar hole (diameter 10 mm) is drilled off. The epidural exploration starts along the thecal sac until the axilla of the exiting root is reached. An extruded or subligamentous disc fragment(s) is removed. If an extensive annular perforation is detected, the disc space should be cleared (20% of the cases).
Same day mobilization.
A total of 84 patients (46 men) underwent the translaminar approach. The mean age was 57 years (range 27–80 years). Follow-up examinations by an independent observer at 1 and 6 weeks; 3, 6 and 12 months and once yearly thereafter (mean follow-up 27 months). Extruded (61%) and subligamentous (39%) disc fragments were found. In 4 cases the translaminar hole was enlarged to a laminotomy. In 12 patients the disc space was cleared. The outcome (MacNab criteria) was excellent (67%), good (27%), fair (5%), and poor (1%). The incidence of recurrent disc herniations was 7%.