Percutaneous Isthmus Foraminoplasty and Full-Endoscopic Lumbar Discectomy for Very Highly Upmigrated Lumbar Disc Herniation: Technique Notes and 2 Years Follow-Up

Abstract

To report the technical notes and clinical outcome of percutaneous isthmus foraminoplasty and full-endoscopic lumbar discectomy (PIF-FELD) for the treatment of very highly upmigrated lumbar disc herniation (VHUM-LDH). From January 2014 to December 2017, 16 patients with VHUM-LDH underwent PIF-FELD surgery. A 10-mm-diameter semi-open foraminoplasty was performed on the dorsal side of the upper intervertebral foramen with lateral isthmus resection by a safe trephine system, in which the facet joint was not injured. Full-endoscopic transforaminal fragmentectomy in the spinal canal and discectomy in the intervertebral space were performed simultaneously. Magnetic resonance imaging of the lumbar spine was reexamined on the second day and 3 months after the operation to evaluate the completeness of the disc fragmentectomy and nerve decompression. The patients were followed up on the visual analog scale (VAS) of lumbar pain and leg pain and Oswestry Disability Index on the second day, 3 months, 6 months, 1 year, and 2 years after operation. The MacNab score and nerve root function recovery were evaluated at 2 years postoperative follow-up. All operations were successfully completed without any change in the surgical method. During the operation, 5 patients were found to have a single sequestered fragment, and the remaining 11 patients had multiple sequestered fragments. There were no complications (e.g., dural tear and nerve injury) during the operation, and no complications (e.g., infection, cerebrospinal fluid leakage, exacerbation of nerve root function injury, and recurrence of intervertebral disc herniation) occurred. Postoperative reexamination of lumbar magnetic resonance imaging in all patients showed complete disc fragmentectomy and adequate nerve decompression. The postoperative low back pain VAS and leg pain VAS scores and Oswestry Disability Index on the second day, 3 months, 6 months, 1 year, and 2 years after operation were significantly improved compared with preoperatively (P < 0.01). At 2 years follow-up, the sensation and muscular strength of the affected nerve root innervation area were significantly restored (P < 0.05), but tendon reflex function was not significantly restored (P > 0.05). At 2 years follow-up, MacNab scores included 6 excellent, 9 good, and 1 fair. PIF-FELD is a safe and effective minimally invasive spine surgery technique for VHUM-LDH.