Fifty-two patients older than sixty years had undergone multilevel lumbar decompression and fusion with instrumentation and reached a minimum two-year follow up. The relationship between abnormal sagittal plane configuration of the proximal segments and the number of lumbar fusion segments was radiographically analyzed. Group A (L1-L5 or S1) patients had two (20%) proximal vertebral compression fractures and four (40%) focal kyphosis. Group B (L2-L5 or S1) patients had one (6%) proximal vertebral compression fractures, five (33%) retrolisthesis and two (13%) focal kyphosis. Group C (L3-S1) had seven (39%) retrolisthesis. Group D had only one retrolisthesis and two disc height loss.

Radiographically analyze the relationship between abnormal sagittal plane configuration of the proximal segments and the number of lumbar fusion segments in patients older than sixty years old.

It appears that lumbar fusion up to L1 causes more kyphotic changes and topping off syndrome in the elderly. Fusion L2-L5 or S1 seems having less severe adjacent level degeneration. Retrolisthesis is a significant problem in fusion from L3-L5 or S1. The least adjacent level degenerative changes were seen in L4-S1 fusion.

Selected limited instrumentation avoiding kyphotic segments or extending the fusion above the thoracolumbar junction may be the needed.

Solid fusion was seen in 46 (88%) patients. There were ten patients in group A, and two (20%) had vertebral compression fractures in the most cranial vertebrae and four (40%) focal kyphosis. Of fifteen patients in group B, one (6%) had compression fracture, five (33%) retrolisthesis, and two (13%) focal kyphosis. Of eighteen patients in group C, retrolisthesis was seen in seven (39%) patients. Group D had nine patients with only one patient having retrolisthesis and two having disc height loss.

Since January 1997, there were fifty-two consecutive patients with an average age of seventy years who have undergone multilevel lumbar decompression and posterolateral fusion with pedicle screw-rod instrumentation, and have reached a minimum two-year follow up. Postoperative radiographs of lumbar fusion were classified into group A (L1-L5 or S1), group B (L2-L5 or S1), group C (L3-L5 or S1) and group D (L4-S1).

Fifteen independent observers of three levels of experience (consultant staff, fellows, residents) assessed 40 radiographs of children presenting with Perthes' disease using the Catterall and the Salter-Thompson grading systems. Each observer was supplied with descriptions and illustrations of the classifications and each hip was grouped by both systems by each observer. The results were statistically analysed using 'kappa' statistics. The level of interobserver agreement was higher for the Salter-Thompson system and correlated with the level of experience of the observer. Both systems can give acceptable levels of interobserver agreement, but the Salter-Thompson grouping is simpler and easier to apply in the earlier stages of the disease when treatment must be decided, and has a higher degree of reproducibility amongst more experienced observers.

Lumbosacral nerve root anomalies have been documented in the literature for over 30 years; however, no significant quantitative studies have been undertaken so far. We describe parallel studies of 100 cadaveric specimens and an equal number of metrizamide myelograms. The anatomical specimens were prepared by wide deroofing of the lumbar canal to permit precise examination of individual nerve roots and their intradural and extradural connections. The incidence of nerve root anomalies was 14%, the L5-S1 level being most commonly involved. In sharp contrast the incidence of nerve root anomalies determined by myelography was only 4%. The anomalies were classified into four groups and the diagnostic and practical implications of our findings are discussed.