The following results were obtained. (1) LF thickness increased with age; however, the increments at L4-5 and L3-4 were larger than one at L2-3 and L5-S1. (2) At L4-5, LF was over 3.0 mm thick in patients in the 20-29 age bracket, and in many of them it was more than 3.5 mm thick. (3) All patients with a thickened LF at L2-3 (>3.0 mm) had very thick LFs at all spinal levels. (4) In elderly patients, there was no correlation between the thickness of LF and the decrease of the disc height. In this study, we concluded that thickening of LF at L4-5 had already started in patients in the 30-39 age bracket and that thickening of the LF was not the buckling of the LF into the spinal canal with disc degeneration. The thickness of LF at L2-3 may serve as an indicator of lumbar spinal canal stenosis at multiple levels.

No abstract

The instantaneous axis of rotation deviated cranially as the stage of pars defects advanced, and as the wedge deformity increased. Kinematic alteration of the lumbar spine in pediatric patients with spondylolysis may affect chondrocytes of the endplate, perhaps contributing to the consequent spine deformities occurring secondarily to spondylolysis.

✓ The authors describe a new endoscopic technique to decompress lumbar nerve roots affected by spondylolysis. Short-term clinical outcome was evaluated. Surgery-related indications were: 1) radiculopathy without low-back pain; 2) no spinal instability demonstrated on dynamic radiographs; and 3) age older than 40 years. Seven patients, four men and three women, fulfilled these criteria and underwent endoscopic decompressive surgery. Their mean age was 60.9 years (range 42–70 years). No subluxation was present in four patients, whereas Meyerding Grade I slippage was demonstrated in three. For endoscopic decompression, a skin incision of 16 to 18 mm in length was made, and fenestration was performed to identify the affected nerve root. The proximal stump of the ragged edge of the spondylotic lesion, and the fibrocartilaginous mass compressing the nerve root were removed. The follow-up period ranged from 6 to 22 months (mean 11.7 months). Clinical outcome was evaluated using Gill criteria; in three patients the outcome was excellent, and in four it was good. This new endoscopic technique was useful in the decompression of nerve roots affected by spondylolysis, the technique was minimally invasive, and the clinical results were acceptable.

MRI revealed a higher prevalence of L3 or L4 spondylolysis than observed with CT.