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: Computer guidance has improved the accuracy and safety of pedicle screw insertion. The aim of this study was to evaluate whether CT-based computer assisted pedicle screw insertion enhances the clinical results of lumbar fusion. Methods: 100 lumbo- and thora-columbosacral operations were randomized either into i) conventional pedicle screw insertion (Group 1) or into ii) computer assisted technique using the SurgiGATE Spine 2.1 optoelectronic navigation system (Group 2). Clinical results were analyzed using the Oswestry index. Radiological analysis was performed by an independent radiologist. Results: 95 patients completed the follow-up. Three had died and two were lost. Thus, there were 48 patients (265 screws) in Group 1, 38 patients (201 screws) in Group 2, and 9 dropouts from the original randomization. There was no statistical difference between the groups regarding age, gender, diagnosis, type of operation, operating time or number of screws per patient. The follow-up time was 24.2 ± 1.6 months. The preoperative Oswestry score in Group 1 was 47.7 ± 16.6, and in Group 2 51.4 ± 16.3 (NS). The postoperative scores were, respectively, 27.1 ± 19.1 and 30.8 ± 22.7 (NS). The fusion rate in Group 1 was 85.1%, and in Group 2 92.1% (NS). In Group 1 4.5% of the screws were loose or broken as compared to 7.0% in Group 2 (NS). Conclusions: Despite superior accuracy, at 2-year follow-up no clinical benefit from computer assisted pedicle screw insertion could be demonstrated in this randomized controlled clinical study.