Study design: Long-term retrospective study of the low grade isthmic Spondylolisthesis treated by means of instrumented posterolateral fixation in adults.

Objective: To evaluate clinical and functional survival of surgical treatment of the espondylolisthesis after minimum 10 years of follow-up. To study the radiologic behaviour of the fused and the adjacent level.

Summary of background: It’s been suggested in many different series that posterolateral instrumented fusion is not always capable to improve the lumbar pain neither to stabilize a vertebral segment if the anterior column is not supported. The need to perform and interbody fusion in the surgical treatment of isthmic spondilolysthesis is still unknown.

Material and method: From a total of 42 patients operated by low grade isthmic espondylolisthesis, it’s been obtained a clinic and radiological follow up in 31 patients, 19 females and 12 males. The average age at the moment of surgery was 34.9 years and in the last review was 46.5 years. The average follow up has been 11.8 years. Pain and functional disability was quantified by a visual analogical Scale (VAS) and the Oswestry Disability Index (ODI). Quality of life was assessed by the SF-36. The preoperative and postoperative percentage of slip and lumbosacral kyphosis was evaluated in serial radiographs at the fused level. The intervertebral disc height and dynamic behaviour was evaluated at the adjacent level.

Results: Spondylolisthesis was present at L5 in 24 patients, L4 in 6 patients and at L3 in 1 patient. In the 87% of cases the fusion was one level and the 3% was two levels. The mean (range) anterior slip at postoperative was 21.9%, and 23.1% at the final follow up. The average angle for the lumbosacral kyphosis was 19.4° in the postoperative and 19.5° in the follow up. The Oswestry Disability Index scores average at follow up was 13,6. 75.8% of patients were considered with a minimum disability and 17.2% with a moderate disability. The 67.7% of the patients develop rewarded activities, the 25.6% develop domestic tasks and the 6.45% are in a disability situation. There was no statistically significant difference between the study population SF-36 scores and those of the general population, same age and gender, in any of the eight domains.

Conclusions: Long-term clinical and radiographic outcomes after “in situ” posterolateral instrumented fusion of adult low-grade Spondylolisthesis were satisfactory. This study further confirms that such surgery is appropriate for these selected patients.

Study design: retrospective clinical study .

Objective: To study radiological late results after posterior stabilization of thoracolumbar fractures with internal fixation. To know factors related with loss of correction and hardware failure.

Summary of background data: The posterior approach using an internal fixator is a standard procedure for stabilizing the injured thoracolumbar spine. None of the surgical techniques used was able to maintain the corrected the kyphosis angle.

Methods: Forty-five patients with thoracolumbar fractures were included in the study. The inclusion criterion was the presence of fracture through the T11-L3 vertebrae without neurologic compromise. The Load-sharing classification has been used for all patients to determine the fracture severity. Surgical techniques (short or long instrumentation) , preoperative and postoperative radiographs ( Cobb technique) and follow-up records of all patients were reviewed carefully from the time of surgery until final follow-up assessment.

Results: 13 patients were treated using short-segment instrumentation (two disc spaces) and 32 patients with long-segment instrumentation (more than two disc spaces). The mean follow-up was 3.4 years (range 1 to 11 years). The mean preoperative Cobb angle was 16.1 degrees and after surgery the mean angle was 6.8° representing an average correction of 9.2 ° . At follow-up assessments the mean Cobb angle was 13.2° representing a loss of correction of 6.4°. Implant failure ( 5 loosening and 8 breakage) was seen in 28.8% of patients: 6/14 (42%) of patients receiving short instrumentation and 7/31 (22%) of patients with long instrumentation. Hardware failure was seen in 53.3% of patients with Cobb angle preoperative more than 20° and in 16.6% of patients with Cobb angle less than 20°.

Conclusions: Radiological behaviour of thoracolumbar fractures treated with posterior instrumentation without anterior support was worse than expected. Hardware failure was related with Cobb angle fracture > 20°, postoperative correction superior than 10° and short pedicular instrumentation technique.