Anatomical characteristics and surgical selections of upper lumbar disc herniation

Abstract

To explore the anatomical characteristics and surgical selections of upper lumbar disc herniation, and evaluate its clinical effects. From January 2009 to January 2013, 26 patients with upper lumbar disc herniation were treated in our department. There were 16 males and 10 females, aged from 28 to 51 years old with an average of 45.7 years, 4 cases were in L₁,₂, 9 cases in L₂,₃, and 13 cases in L₃,₄. The data was collected including distance between outer edge of lower facet and the spinous process, the outer edge of the isthmus and spinous process, the lower edge of lamina and the upper edge of the intervertebral space, nerve root arising points and lower edge of the corresponding pedicle. Transforaminal discectomy and interbody fusion combined with pedicle screw fixation was performed in patients with L₁,₂, L₂,₃ herniated disk and 5 patients with L₃,₄ herniated disk complicated with lumbar instability. However another 8 patients with L₃,₄ herniated disk were treated with posterior fenestration decompression. Clinical effects were evaluated by Japanese Orthopaedic Association(JOA). The relative height rate(R) of the intervertebral space was measured preoperatively and 1 year postoperatively. The fusion of the bone graft was also observed. Intraoperative anatomical measurement was taken in all patients. All patients were followed up for more than 1 year with an average of 16 months, and all incisions got healing, JOA was improved from preoperative(10.13±1.49) points to last follow up (25.21±2.13) points with the improvement rate of 79.9%. Among the patients underwent fusion operation, 17 cases obtained bone fusion and 1 case maybe non fusion and no internal fixation failure was found;the R value was (0.231±0.056) mm preoperatively, however (0.345±0.076) mm at 1 year after operation with statistical difference(P<0.05). In the patient underwent posterior fenestration decompression, the R value was(0.243±0.036) mm preoperatively, and (0.212±0.046) mm at 1 year after operation without statistical difference (P>0.05). No spinal instability and lumbar disc herniation recurrence were found in these patients. According to the anatomical characteristics of L₁,₂ and L₃,₄ herniated disk, these patients could be treated with transforaminal discectomy and interbody fusion. The anatomical characteristics and clinical manifestations of L₃,₄ herniated disk is similar with the lower lumbar disc herniation, for the patients, an appropriate surgical method should be chosen according to the lumbar stability.