Introduction: L5-S1 transforaminal percutaneous endoscopic lumbar discectomy (PELD) is a demanding procedure owing to structures such as the iliac crest, L5 transverse process, hypertrophic L5-S1 facet joint, and sacral ala. There has been no definite preoperative evaluation method to assess the surgical validity of L5-S1 transforaminal PELD.
Methods: Twelve patients diagnosed L5-S1 disc herniation underwent preoperative evaluation using this new method. The skin marker was attached to the patient’s back as a tentative skin entry point, determined by the usual preoperative MRI or CT. A new tilted axial and coronal MRI or CT was performed in accordance with the axis of the L5-S1 transforaminal working channel. The images could help us determine whether the iliac crest hindered the PELD trajectory. Success rate of transforaminal PELD according to height of the iliac crest was obtained.
Results: Six patients underwent a transforaminal PELD, with favorable outcomes. The other six patients were considered “unsuitable” for transforaminal PELD owing to the probable blockade by the iliac crest.
Conclusions: L5-S1 transforaminal PELD trajectory could be evaluated precisely by tilted MRI or CT. This novel method may help achieve favorable outcomes.
Patient Care: With this new preoperative evaluation method, surgeon can know whether L5-S1 transforaminal PELD is possible and exac skin entry point will increase success rate.
Learning Objectives: By conclusion of this session, participants should be able to obtain new tilted MRI or CT cut image which will help to determine skin entry point of L5-S1 transforaminal PELD.