Background data. The clinical outcome of decompression and posterolateral spinal fusion for patients with degenerative lumbar spinal stenosis may be influenced by a variety of pathophysiologic factors. Among them, sagittal balance of the spine has gained new interest regarding its correlation with low back pain following lumbar spine surgery.

Objectives. To study the effect of sagittal spinal alignment on low back pain in patients operated for degenerative lumbar spinal stenosis.

Study design. Multifactorial analysis.

Materials and Methods. In this prospective randomized comparative study 45 consecutive patients were included, who underwent decompression for symptomatic degenerative lumbar spinal stenosis and two-, three- or four levels posterior transpedicular fixation with three instrumentations of different stiffness (dynamic, semirigid and rigid) plus posterolateral fusion. All patients were followed up for an average period of four-year radiologically and with SF-36 (domain Bodily pain) to investigate possible correlations between anthropometric parameters, stiffness and extension of instrumentation, roentgenographic sagittal balance, motion in adjacent free level and low back pain.

Results. Bodily pain scores improved with the time lapsed from index operation (P< 0.0001). As the distance of the apical lumbar vertebra from plumbline increased, bodily pain score improved significantly (P=0.0006). At the last observation following surgery patients had better Bodily pain score than that they had preoperatively (P=0.0001) and six months postoperatively (P< 0.0001) respectively. Patients, who received four levels instrumentation had higher Bodily pain score (P=0.0245) than their counterparts who received two levels instrumentation.

Discussion. Maintenance or even improvement of lumbar lordosis, instrumentation of three and four vertebrae, and time lapsed from index operation was associated with improvement of back pain. On contrary, patients’ age, gender, instrumentation stiffness, vertebral inclination, thoracic kyphosis and sagittal lumbar flexibility did not affect the surgical outcome regarding back pain in adult patients who underwent decompression and stabilization 2 to 4 levels for degenerative lumbar spinal stenosis.

Purpose: Prospective randomized clinical and radiological study to compare the evolution of instrumented posterolateral lumbosacral fusion using either coralline hydroxyapatite(CHA), or iliac bone graft(IBG) in three comparable groups of patients.

Methods: 56 randomly selected adult patients with spinal stenosis were divided into three groups(A,B,C) included 17, 19 and 20 patients respectively and underwent decompression and fusion. The spines of Group A received IBG ; Group B IBG on the left side and CHA mixed with local bone and bone marrow on the right side; Group C CHA mixed with local bone and bone marrow bilaterally. The patients’s age was 61+11, 64+8 and 58+8 years for groups A, B and C respectively. SF-36, Oswestry Disability Index, and Roland-Morris surveys were used. Visual Analog pain Scale was used for pain. Roentgenograms (AP, lateral and oblique plus bending views) and CT-scans were used to evaluate the evolution of fusion. Two independent observers tested variability in evolution of the dorsolateral bony fusion 3 to 48 months postoperatively with the Christiansen’s and CHA resorption in Groups B and C.

Results: Intraobserver and interobserver agreement (r) for radiological fusion was 0.71 and 0.69 respectively, and 0.83 and 0.76 for evaluation of CHA resorption. There was no visible pseudarthrosis. Fusion was achieved one year postoperatively. CHA resorped 6 months postoperatively at the intertransverse spaces. Bone bridging started 3 months postoperatively in all levels posteriorly as well as between the transverse processes where IBG was applied. SF-36, Oswestry Disability Index, and Roland-Morris Score improved > 20 postoperatively in all groups. There was one pedicle screw breakage at the lowermost-instrumented level in group A and two in group C without pseudarthrosis. There was no deep infection. Operative time and blood loss were less in group C, while donor site complaints were observed in the patients of the groups A and B only.

Discussion & Conclusion: This study showed that autologous IBG remains the gold standard for posterior instrumented lumbar fusion to which each new graft should be compared. CHA was proven in this series not appropriate for intertransverse posterolateral fusion because the host bone in this area is little.