Wednesday, September 26, 2018 1:00 PM – 2:00 PM What's New in MIS: 37. Transforaminal percutaneous endoscopic lumbar discectomy for upward migration of upper lumbar foraminal discherniation: clinical and radiological outcomes and technical considerations

Abstract

PURPOSE Upper lumbar disc herniations occur from the L1-2 to L3-4 level. Compared with lower lumbar disc herniation, conventional open microdiscectomy for upward migration of upper lumbar foraminal disc herniation is associated with a higher risk of isthmic injury and wide facetectomy, which can consequently result in postoperative back pain and segmental instability. To date, there are no published studies on the feasibility of percutaneous endoscopic lumbar discectomy (PELD) for upward migrated foraminal disc herniation of upper lumbar; hence, the purpose of this study was to assess the clinical and radiologicoutcomes and the technical pitfalls of PELD for upper lumbar foraminal disc herniation with upward migration. METHODS Twenty-five patients with upward migrated foraminal disc herniation at the L1-2, L2-3, and L3-4 levels who were treated by PELD under epidural anesthesia were enrolled in this study. The clinical outcomes were assessed using the Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) of pain, and any complications related to the operation were analyzed. Moreover, the radiological outcomes were investigated using postoperative magnetic resonance imaging (MRI) and plain radiography. According to the preoperative sagittal magnetic resonance images, disc upward migration was classified into three zones (A, B, and C) according to the pedicle and vertebral endplates. Zones A and B were defined as the area from the lower margin of the pedicle to the lower endplate, with zone B comprising the upper half and zone A, the lower half. Zone C was defined as the area above the lower margin of the pedicle. We compared the postoperative results according to these disc migration zones. RESULTS All patients were followed for more than 2 years. The mean age was 51.1±14.9 years. Disc migrations were localized in zones A, B, and C in 13, six and six patients, respectively. After PELD, the ODI and VAS score significantly decreased from 69.8±6.5 and 8.1±0.7 to 17.5±4.4 and 2.0±0.7, respectively regardless of the disc migration zones. In 23(92%) out of the 25 patients, the ruptured disc particles were completely removed, as confirmed by postoperative MRI. In zone C, which was defined as disc migration above the lower margin of pedicle, a small remnant disc particle was detected in two patients. However, even in these two patients, the symptoms were improved after PELD. Early recurrence of the herniated disc occurred at the operated segment in one patient with a zone C migration disc. In all patients, the disc height and lordosis were well maintained at the latest follow-up. There were no significant complications related to PELD, except transient numbness and a tingling sensation in the leg in three patients. CONCLUSIONS PELD is a safe and effective treatment option for upward migrated foraminal disc herniation of the upper lumbar area. From anatomical aspect, it is associated with a relatively wide foramen as well as a lower incidence of spinal stenosis. In addition, our results suggest that PELD may prevent complications related to general endotracheal anesthesia and iatrogenic isthmic fracture, violation of facet joint and cauda equina injury. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.