The purpose was to analyze preoperative symptoms, curve characteristics, and outcome of surgery in patients operated on for isthmic spondylolisthesis with concomitant scoliosis. Overall, 151(9.1%) of 1667 scoliosis patients had spondylolisthesis treated surgically in 21 (13.9%)(19 females, 2 males; 11 low-, 10 high-grade). Patients' age at admission was 13.5(10-17)y. Preoperatively, 5/21 were pain-free (1 high-grade, 4 low-grade), 7 (2 high-grade) had LBP, 2 (both high-grade) radiating pain, and 7 (5 high-grade) had both. Hamstring tightness was present in 5/10 high-grades. Scoliosis was primary thoracic in 3/11 low-grade and secondary lumbar with oblique rotated take-off of L5 in 8/11 low-grade patients. Of the high-grades, 7/10 had sciatic curves and 3 secondary lumbar. In low-grades, the main indication for surgery was pain in 3/11 and lumbar curve progression or the intent to prevent it in 7/11. The operative technique was uninstrumented posterolateral fusion in 8/11, instrumented L4-S1 fusion with reduction of L4-tilt in 2, and direct repair in 1 patient. High-grades were fused to prevent further slipping regardless of subjective symptoms (uninstrumented anterior 5, combined 2, instrumented reduction 3). Selective thoracic fusion for scoliosis was performed in 3 patients. None of the lumbar curves needed fusion. All sciatic curves resolved. The follow-up time was 10.6(2-21)y. Of the low-grade patients, 5 were pain-free, 4 had moderate pain, and 2 had a severe chronic pain syndrome. One had broken pedicle screws without sequelae. Of the high-grade patients, 4 were pain-free, 6 had moderate pain. One had a pain-free peroneal weakness after slip reduction.

Aims: To find a long-term effect of posterolateral fusion for isthmic spondylolysis and spondylolisthesis on lumbar spine.

Methods: A posterolateral fusion was performed on 56 patients (30 females, 26 males) with an average age of 16 (range 11 to 20) years. A clinical and MRI examination was performed on these patients on average 18 years later (range 11 to 25 years). The size of the spinal canal were assessed. Disc space, degeneration and protrusions were evaluated. Bone marrow changes (Modic I & II), facet joint degeneration and the state of the spinal muscles were assessed.

Results: In MR images, none of the patients had lumbar spinal stenosis. In contrast, the spinal canal was wide in the level spondylolysis and spondylolisthesis. Narrowing of the neural foramina was noted in 13 (23%) patients. This was associated usually in severe slip (> 50%) and was noted always at the L5-S1 level. Of the studied 332 intervertebral discs 56 (17%) were speckled and 57 (17%) were black and 76 (23%) narrowed. Most commonly speckled/black and narrowed disc was found in the two lowest lumbar levels. Only one patient, 41-year-old female, had prolapse. Modic I and II changes were noted in 7 (2%) and 9 (3%) intervertebral disc levels, respectively. Degenerative-like facet joint hypertrophy was noted in 47 (48%) of the studied levels. Of the patients, seven (12%) had muscular atrophy.

Conclusions: Stenosis of neural foramina may be associated to severe spondyolisthesis. Degenerative changes were found most commonly found in the level of the spondylolysis and spondylolisthesis and above fusion level. Bone marrow changes associated with disc degeneration were rare.