Modified unilateral biportal endoscopic transpedicular discectomy for highly migrated upper lumbar disc herniation: a case report.

Upper Lumbar Disc Herniation (ULDH) is a rare form of lumbar disc herniation, but its symptoms are more severe due to the conus medullaris and the tight spinal canal. Surgical intervention for these fragments is also considered demanding once they demonstrate high-grade downward migration into the "hidden zone" medial to the pedicle. Obstructions due to bone or dangers of damaging nerve tissue by retraction are common limitations of the classical minimally invasive methods. We report on the case of a 69-year-old man with an extreme down-migrated L1-L2 disc herniation (Lee classification Zone 4). The patient had severe left thigh pain and numbness and was unable to walk, with preoperative VAS and ODI scores of 7/10 and 74, respectively. A modified posterior transpedicular approach utilizing Unilateral Biportal Endoscopy (UBE) was successfully conducted. The use of the medial cortical wall of the pedicle as a natural navigational "Cortical Guidance" guides a direct path to the ventral pathology through minimal bone removal and results in true "Zero-Retraction" of the neural structures. Herniated fragments were totally resected postoperatively and the discectomy patient showed significant symptomatic improvement with VAS and ODI scores reduced to 1/10 and 12, respectively. At the 6-month follow-up, the patient had complete neurological recovery. The modified posterior transpedicular UBE technique is a safe, simple, and effective approach for the treatment of highly migrated ULDH and enables extensive decompression with maximal preservation of spinal stability.