gms | German Medical Science

Objective: The translaminar approach (TA) was originally introduced for removal of cranially migrated foraminal lumbar disc herniation (LDH). In comparison to the conventional interlaminar approach, extensive removal of the lamina and of parts of the facet joint can be avoided, which is a major advantage. Potentially, the TA can be centered right to the pathology including downward migrated LDH. The aim of our study was to demonstrate the versatility of the TA using an anatomical classification of disc herniation treated at our institution.

Method: 17 consecutive patients who underwent microsurgical subperiostal or transmuscular removal of a LDH using the TA from 5/2012 to 10/2015 were retrospectively analyzed. Only patients with complete preoperative MRI dataset that allowed a 3D reconstruction and a proper neuroradiological assessment were included in the study. Based on these images LDH were classified according to Lee (Lee et al., Eur Spine J 2007) and due to their relationship to the exiting or traversing nerve root. Perioperative data were extracted from an electronic in-house database and long-term follow-up was assessed by a telephone interview conducted at 11/2015. Clinical outcome was measured using the Macnab criteria (4-point scale; 1 point: excellent outcome).

Results: The median age of our cohort was 61.7 years and the median follow-up of our cohort was 23 months. Preoperative MRI scans revealed a far-upward disc herniation in 9 patients, a near-upward herniation in 3 patients, a near-downward herniation in 1 patient, and a far-downward herniation in 4 patients according to the Lee classification. In 56.2 % of the patients LDH was localized medial to the nerve root, and in 42.8 % lateral to the nerve root. In the majority of cases the TA was carried out at the lamina L4 (23.5 %) or L5 (41.1 %). The approach was sufficient for sequestrectomy in all patients. There were no treatment-related complications and no cases of recurrent disc herniation. One patient underwent later microsurgery for a disc herniation at another lumbar level. No patient required fusion surgery for secondary instability. Satisfactory (excellent or good) long-term outcome was found in 86.7% of the patients.

Conclusions: The translaminar approach is very versatile and can be individualized for microsurgical removal of a wide range of cranially and caudally migrated lumbar disc herniation. Furthermore, the approach is safe, maintains segmental stability, and leads to good clinical results.