Pars interarticularis fenestration in the treatment of foraminal lumbar disc herniation: a further surgical approach.

Abstract

A new surgical approach to foraminal disc herniation is proposed. The procedure was performed in 28 patients during a span of 3 years. The herniation was purely foraminal in 18 patients and mainly foraminal with a definite extraforaminal component in the other 10 patients. Surgical treatment was offered only after 6 weeks of therapy with anti-inflammatory drugs and strict bed rest had proved to be ineffective. To unroof the foraminal compartment, an ovoid fenestration (10 x 5 mm) is cut, with its major longitudinal axis at the level of the pars interarticularis, just medially and slightly off-center under the lateral isthmic notch, i.e., below the pedicle projection. This fenestration exposes the foraminal root compressed by the herniated disc, which can be easily removed. Treatment was successful in all patients, with swift remission of pain and only mild postoperative discomfort. All patients resumed their occupations as usual within 10 to 30 days after the operation, according to type of work. Mean follow-up is 24 months (range, 12-36 mo), without any return of pain. We propose pars interarticularis fenestration because it spares, with minimal bone removal, the facet joints and the anatomic continuity of the pars interarticularis, yet properly exposes the foraminal compartment both medially and laterally and thereby permits optimal removal of the disc herniation.