71. Can the novel lumboiliac triangle technique based on biplane oblique fluoroscopy facilitate transforaminal percutaneous endoscopic lumbar discectomy for patients with L5-S1 disc herniation combined with high iliac crest? A case-control study of 100 patients

Abstract

BACKGROUND CONTEXT Percutaneous endoscopic lumbar discectomy (PELD) via the transforaminal approach is difficult at L5-S1 in patients presenting with high iliac crests (HIC). The conventional wisdom is that measurement using lumbar radiography, CT or MRI is necessary. PURPOSE To introduce a lumbo-iliac triangular (LI-Tri) technique based on biplane oblique fluoroscopy and verify whether it facilitates transforaminal PELD for patients with L5-S1 LDH combined with HIC. STUDY DESIGN/SETTING Retrospective case-control study. PATIENT SAMPLE The definition of HIC is derived from Choi's degree system, classifying the relationship between the location of the highest point of the iliac crest and the adjacent bony structures such as the L5 pedicle, and the L4 inferior and S1 superior endplates. In our patient selection, the highest point of the iliac crest above the mid-point of the L5 pedicle (Type>5) was regarded as ‘HIC.’ Between January 2016 and December 2016, 100 patients with LDH combined with HIC were treated with PELD via a unilateral transforaminal approach in two tertiary spine centers. Inclusion criteria were as follows: (1) clinical symptoms and signs of unilateral neurological deficit including radiculopathy, paresthesia, motor weakness that did not respond to conservative treatments including medication, physiotherapy, and nerve root blocks for 6 weeks; (2) symptoms corresponding to preoperative MRI and/or CT scans. Exclusion criteria were as follows: (1) definite segmental instability (anterior or posterior displacement>3 mm or the angle change of the endplate>15 ° on the dynamic radiography); (2) severe central canal stenosis (less than 10 mm) on preoperative MRI or CT; (3) cauda equina syndrome; (4) highly migrated nucleus pulposus beyond the low rims of adjacent pedicles; and (5) suspected infection or malignant diseases. OUTCOME MEASURES Besides the mean operative duration, clinical outcome evaluation included the Oswestry Disability Index (ODI) score and visual analog scale (VAS) score without the usage of analgesic to truly reflect the intensity of back and leg pain. Relevant complications, including intraoperative conversion from conventional puncture to LI-Tri technique, postoperative dysthesias and motor weakness were also recorded. METHODS The LI-Tri technique was used in the first 50 patients (applied group) with L5-S1 disc herniation. The other 50 patients were classified as non-applied group, in which the conventional puncture process was performed. The puncture location was considered unsatisfactory after 20 puncture attempts, regarded as a difficult puncture. If this occurred in the non-applied group, the LI-Tri technique was introduced into the puncture process, as with the applied group. Three senior surgeons with experience of over 500 transforaminal PELD cases performed the surgeries. The intervals of follow-up were scheduled at 1 day, 1, 3, 6, 12 and 24 months after surgery. Postoperative MRI or CT examinations were recommended, especially for patients without satisfactory symptom relief. RESULTS No significant difference was observed with respect to demographic information (P .05, respectively). With the exception of the back pain VAS and ODI at 1 day postoperatively, no significant difference was observed in the three parameters at other time-points postoperatively between two groups (P>.05, respectively). CONCLUSIONS For patients with L5-S1 LDH combined with HIC treated by transforaminal PELD, the LI-Tri technique is simple and effective in preoperative evaluations, locating the skin entry point and guiding the puncture trajectory. Compared to the conventional technique, it shows advantages in terms of reducing intraoperative surgical duration and promoting fast postoperative recovery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.