Percutaneous Endoscopic Diskectomy using an Interlaminar Approach Based on 3D CT/MR Fusion Imaging.

BACKGROUND: With effective preoperative planning, percutaneous endoscopic diskectomy (PED) via an interlaminar approach (PED-IL) can reduce the need for partial laminectomy. Our aim was to assess the clinical outcomes of PED-IL, planned using three-dimensional fusion of computed tomography and magnetic resonance (3D CT/MR) images.

MATERIAL AND METHODS: Our retrospective analysis was based on data from 102 patients (66 were men) treated by PED-IL. Preoperative planning was based on the positional relationship between the nerve root and the lumbar disk herniation, visualized on 3D CT/MR fusion images through a simulated IL window. Two approaches were planned: type I, via a partial window opening of the ligamentum flavum, and type II, via a partial IL window opening and partial laminectomy. Decisions were then made to approach the herniation from the shoulder (subtype s) or axillary (subtype a) portion of the nerve, or we used a combination of both approaches (subtype a + s). Operative time and the pre- to postsurgical change in pain and pain-related disability scores (Japanese Orthopaedic Association Back Pain Evaluation Questionnaire scores) were evaluated. The number of cases in which the preoperative planned surgery was modified intraoperatively and the incidence of complications were also evaluated.

RESULTS: A type I approach was planned in 30 cases (29.4%) and type II in 72 cases (70.6%). Intraoperative change from type I to type II was required in two cases. The mean operative time was longer for type II than type I procedures. Pain and pain-related disability scores improved in all patients, and only one case of dural sleeve damage was identified.

CONCLUSIONS: Preoperative planning using a simulated IL window to visualize the 3D regional anatomy is effective in predicting the feasibility of a PED-IL.