Karsten Thomsen

Long-Term Functional Outcome of Pedicle Screw Instrumentation as a Support for Posterolateral Spinal Fusion : Randomized Clinical Study With a 5-Year Follow-up

Study Design. A prospective randomized clinical study with a 5-year follow-up. Objectives. To analyze the long-term effect of supplementary transpedicular screw fixation on reoperation rate and functional outcome. Summary of Background Data. Within the past few years the benefit of supplemental pedicle screw fixation has been questioned as a standard procedure in lumbar spinal fusion surgery. The long-term effect of supplemental pedicle screw fixation is still unknown. Methods. From 1992 through 1994 a total of 129 patients with severe chronic low back pain were randomly selected for either supplemental pedicle screw fixation (instrumented) or no pedicle screw instrumentation (noninstrumented) posterolateral spinal fusion. The Dallas Pain Questionnaire, Low Back Pain Rating Scale, and a questionnaire concerning work status assessed the outcome. Results. A 5-year follow-up of 93% showed that the instrumented group had a 25% reoperation rate (removal of instrumentation with and without second fusion) compared with a reoperation rate of 14% in the noninstrumented group (fusion and decompression) (P < 0.03). A total of 51% were capable of working after 5 years compared with 40% before surgery. There was no difference in work capacity between the two groups at any point of observation. Overall, there was no significant difference between the instrumented and noninstrumented groups in regard to functional outcome as measured by both the Dallas Pain Questionnaire and Low Back Pain Rating Scale. When analyzing diagnostic subgroups at the 5-year follow-up, patients with isthmic spondylolisthesis had a significantly better outcome by use of a posterolateral fusion without supplemental instrumentation compared with an instrumented fusion (P < 0.03). However, patients with primary degenerative instability improved significantly more when instrumentation supported the posterolateral spinal fusions (P < 0.02). To the question “was it worth it?” 67% answered “yes” in the instrumented group whereas 70% did so in the noninstrumented groups (not significant). Conclusion. The long-term functional outcome of posterolateral spinal fusion improved significantly for boththose with and without pedicle screw instrumentation, with a global 70% satisfaction reported by the patients. Patients with isthmic spondylolisthesis Grades 1 and 2 with noninstrumented fusion had superior long-term outcomes after posterolateral spinal fusion in comparison with an instrumented fusion. In contrast, patients diagnosed as having primary degenerative instability improved significantly when the posterolateral fusion was supported by instrumentation. In actuality, pedicle screw instrumentation increased reoperation rate compared with noninstrumented posterolateral fusion.

Twelve-months follow-up in forty-nine patients with acute/semiacute osteoporotic vertebral fractures treated conservatively or with percutaneous vertebroplasty: a clinical randomized study.

Study Design. Clinical randomized study. Objective. Percutaneous vertebroplasty is compared to conservative treatment in patients with acute or subacute osteoporotic vertebral fractures with respect to pain, physical and mental outcomes. The risk of vertebral fractures adjacent to treated levels is assessed. Summary of Background Data. There are some disagreements of the benefits of PVP for the treatment of acute osteoporotic vertebral fractures, but the long-term clinical outcome of PVP compared to conservative treatment has not been evaluated in a randomized study. Methods. The 3-months follow-up of this study has been published previously, and here we report the completed 12-months analysis. About 50 patients (41 females) were included from January 2001 until January 2008. Patients with vertebral fractures less than 8 weeks old were included and randomized to either PVP or conservative treatment. Pain was assessed with a visual analogue scale. Physical and mental outcomes were assessed by validated questionnaires and tests. Tests, questionnaires, and plain radiographs were performed at the inclusion and after 3 and 12 months. Results. Pain score before and after the operation in the PVP group was 7.9 and 2.0, respectively. There was no difference between the groups concerning pain at the 3- and 12-months follow-up. Supplementary assessment of back pain 1 month after discharge from hospital showed a significant lower VAS score in the PVP group over the conservative group. In the study period, 2 adjacent fractures in the PVP group and no adjacent fractures in the conservative group were registered. Conclusion. PVP is a good treatment for some patients with acute/subacute painful osteoporotic vertebral fractures, but the majority of fractures will heal after 8 to 12 weeks of conservative treatment with subsequent decline in pain. The risk of new fractures needs further research.

Percutaneous vertebroplasty compared to conservative treatment in patients with painful acute or subacute osteoporotic vertebral fractures: three-months follow-up in a clinical randomized study.

Study Design. Clinical randomized study. Objective. The aim of this study is to compare percutaneous vertebroplasty (PVP) to conservative treatment of patients with osteoporotic vertebral fractures in a clinical randomized study with respect to pain, physical and mental outcome, and to asses the risk of adjacent fractures. Summary of Background Data. PVP is a therapeutic procedure performed to reduce pain in vertebral lesions. Despite the lack of comparative randomized clinical trials PVP is generally seen as a safe and efficient procedure for painful osteoporotic fractures. Methods. Fifty patients (41 females) were included from January 2001 until January 2008. Patients with acute (<2 weeks) and subacute (between 2 and 8 weeks) osteoporotic fractures were included and randomized to either PVP or conservative treatment. Pain was assessed with a visual analogue scale and physical and mental outcome were assessed by validated questionnaires and tests. Tests, questionnaires, and plain radiographs were performed at the inclusion and after 3 months. Results. Reduction in pain from initial visit to 3-month follow-up was comparable in the 2 groups (P = 0.33) from approximate visual analogue scale 8.0 to visual analogue scale 2.0, intragroup difference was significant (P = 0.00). Reduction in pain in the PVP group was immediate 12 to 24 hours after the procedure (P = 0.00). There was no significant difference in the other parameters when comparing the results at inclusion and after 3 months within both groups and between the groups after 3 months with a few exceptions. We observed 2 adjacent fractures in the PVP group and non in the conservative group. Conclusion. The majority of patients with acute or subacute painful osteoporotic compression fractures in the spine will recover after a few months of conservative treatment. The risk of adjacent fractures needs further research. No major adverse events were observed.

Interobserver and Intraobserver Agreement of Radiograph Interpretation With and Without Pedicle Screw Implants : The Need for a Detailed Classification System in Posterolateral Spinal Fusion

Study Design. A prospective randomized clinical study in which four observers evaluated radiographs of posterolateral fusion masses. Objectives. To evaluate the accuracy of radiograph interpretation of the posterolateral spinal fusion mass when using a detailed classification system and to analyze the influence of metallic internal fixation devices on radiologic inaccuracy. Summary of Background Data. In general, the literature describing the classification criteria used for radiograph interpretation of spinal posterolateral fusion has serious deficiencies. There is a need for a detailed classification system. Methods. Seventy patients were randomly allocated to receive no instrumentation (n = 36) or Cotrel–Dubousset instrumentation (n = 34) in posterolateral lumbar fusion. All four observers participated in a prestudy discussion and evaluated the radiographs (anteroposterior, lateral) taken at the 1-year follow-up evaluation. The observers scored the radiographs twice (30 days apart). Each level on each side was judged separately. A continuous intertransverse bony bridge involving at minimum one of the two sides indicated a fusion at that level. “Fusion” indicated this quality of fusion at all intended levels. If the fusion was doubtful on both sides of the interspace, the individual case could not be classified as “fused.” Results. The mean interobserver agreement was 86% (Kappa 0.53), and the mean intraobserver agreement was 93% (Kappa 0.78). No difference in interobserver and intraobserver agreement was found between patients with and without supplementary pedicle screw fixation. All mean Kappa values were classified as fair or good. The four observers identified a mean fusion rate of 81%. Conclusion. It is extremely difficult to interpret radiographic lumbar posterolateral fusion success. Such an assessment needs to be performed by use of a detailed radiographic classification system. The classification system presented here revealed good interobserver and intraobserver agreement, both with and without instrumentation. The classification showed acceptable reliability and may be one way to improve interstudy and intrastudycorrelation of radiologic outcomes after posterolateral spinal fusion. Instrumentation did not influence reproducibility but may result in slightly underestimated fusion rates.

Outcome at 10 years after treatment for adolescent idiopathic scoliosis

Study Design. A total of 215 consecutive patients treated either by bracing or operation received a questionnaire after 9.7 years. Objective. The aim of the present study was to elucidate the long-term outcome in a group of brace (BT) or surgical treated (ST) patients suffering AIS. Summary of Background Data. In adolescent idiopathic scoliosis (AIS), the options are BT or ST and, together with the disease itself, they may both be physically and psychologically demanding. Methods. The main topics of a questionnaire were demographics, back pain, activities of daily living, and SF-36. Results. A total of 181 replied. The mean age at follow-up was 26.0 years. The level of back or leg pain was relatively low, and the BT patients had more pain than their ST peers. We saw a generally high level of ADL and found no significant difference between BT and ST patients in the present study for any of the SF-36 variables. Compared with age-matched controls, the SF-36 scores were lower in the AIS patients. Brace related questions revealed a significant impact of the disease and the treatment on the patients’ lives. Conclusions. The patients had moderately reduced perceived health status and activities of daily living, and increased pain with the ST patients generally at a better level than the BT.

Adolescent idiopathic scoliosis in twins: a population-based survey.

Study Design. A questionnaire-based identification of adolescent idiopathic scoliosis (AIS) patients in a twin cohort. Objective. The purpose of this study was to establish a scoliosis twin cohort to provide data on the heritability of AIS. Summary of Background Data. The etiology of AIS is still unclear, and the true mode of inheritance has yet to be established. Concordance rates in monozygotic twins have been reported to be between 0.73 and 0.92, and in dizygotic twins between 0.36 and 0.63. Studies on concordance in twin pairs provide a basis for analyzing the influence of genetic versus environmental factors. Methods. All 46,418 twins registered in the Danish Twin Registry born from 1931 to 1982 were sent a questionnaire, which included questions about scoliosis. A total of 34,944 (75.3%) representing 23,204 pairs returned the questionnaire. Results. A subgroup of 220 subjects considered to have AIS was identified, thus giving a prevalence of 1.05%. The concordant twin pairs were all monozygotic. Pairwise, the concordance rate was 0.13 for monozygotic and zero for dizygotic twin pairs; proband-wise concordance was 0.25 for monozygotic and zero for dizygotic pairs. The concordance of monozygotic and dizygotic pairs was significantly different (P < 0.05). Conclusion. We have found evidence for a genetic etiology in AIS, but the risk of developing scoliosis in 1 twin whose other twin has scoliosis is smaller than believed up until now.

Early weaning might reduce the psychological strain of Boston bracing: a study of 136 patients with adolescent idiopathic scoliosis at 3.5 years after termination of brace treatment.

From 1983 to 1990 a total of 136 patients with adolescent idiopathic scoliosis were treated with the Boston brace. With the aim of examining the social and psychological impact of the brace treatment all patients received a questionnaire at an average of 3.5 years after termination of the treatment. Ninety-three percent responded to the questionnaire. The overall picture was that the patients daily activities and social contacts, not least with the opposite sex, were affected both during the bracing period and at follow-up. It is important that the indications for the treatment are assured, and weaning should be initiated at the latest 3 years after menarche.

Genetic epidemiology of Scheuermann's disease

Background and purpose The genetic/environmental etiology of Scheuermanns disease is unclear. We estimated the heritability of the disease using an etiological model adjusted for sex and time of diagnosis, and examined whether the prevalence of Scheuermanns disease was constant over time. Methods 46,418 twins were sent a questionnaire about health and disease. Of these, 75% returned the questionnaire and 97% answered the question “Have you been diagnosed as having Scheuermanns disease by a doctor?” Results Responders included 11,436 complete pairs of twins. Data were analysed using classical twin modeling methods. Tetrachoric correlations were used to decide which etiological model to fit. The best-fitting model was the AE model. Heritability was 0.74 (95% CI: 0.65–0.81), while variance explained by environmental factors was 0.26 (95% CI: 0.19–0.35). A threshold of 2.1 (95% CI: 1.9–2.2) was calculated, corresponding to a prevalence of 1.9% (95% CI: 1.3–2.8) for women. Regression coefficients for age and sex were 0.000 (95% CI: –0.003 to 0.002) and –0.32 (95% CI: –0.42 to –0.23). Interpretation We found a heritability of 0.74 in Scheuermanns disease. The threshold in men was lower than in women, corresponding to a male prevalence that was almost twice that of females. We found no change in the prevalence of Scheuermanns disease throughout the 50-year age span that we examined.

The influence of lumbar lordosis on spinal fusion and functional outcome after posterolateral spinal fusion with and without pedicle screw instrumentation.

The aim of the current study was to examine the correlation between lumbar lordosis, spinal fusion, and functional outcome in patients suffering from severe low back pain, treated by posterolateral spinal fusion with or without pedicle screw instrumentation. One hundred thirty patients were randomly allocated to posterolateral lumbar fusion with or without Cotrel-Dubousset instrumentation. Functional outcome was assessed preoperatively, and 1 and 2 years postoperatively. Lordosis angles of the lumbar spine and fusion rates were assessed at the 1- and 2-year follow-up. No difference in lordosis angle was found between the two groups at any time. Lordosis was unchanged at 2 years compared with preoperative status in both groups. In the instrumented group, nonunion (23%) was followed by a decrease in lordosis at follow-up (p < 0.05). However, in the noninstrumented group, nonunion (14%) resulted in increased lordosis (p < 0.05). No correlation was found between functional outcome and lordosis angle. The current study showed no correlation between functional outcome and lordosis angle either before or after posterolateral spinal fusion. Use of instrumentation did not influence lumbar spinal alignment compared with noninstrumented fusions. The sagittal alignment was stable both 1 and 2 years after solid fusion. The failure mode of instrumented fusions was a reduced degree of lordosis in contrast to an increased degree of lordosis in patients with noninstrumented fusion.

Perceived health status in self-reported adolescent idiopathic scoliosis: a survey based on a population of twins.

Study Design. A questionnaire-based identification of adolescent idiopathic scoliosis (AIS) patients and measure of Short Form-12 (SF-12) in a big twin-cohort. Objective. The purpose was to study the effect that AIS has on the health-related quality of life in the patients. Summary of Background Data. The effect of AIS on the perceived health status is still unclear. Methods. All 46,418 twins registered in the Danish Twin Registry born between 1931 and 1982 were sent a questionnaire including SF-12. The questionnaire was returned by 34,944 (75.3%) twins representing 23,204 pairs. Results. A group of 220 subjects considered to have AIS was identified corresponding to a prevalence of 1.05%. In this group, the SF-12 could be calculated in 187 twins. Conclusion. We found the perceived both mental and physical health status from SF-12 to be moderately but significantly worse than in controls. Approximately 75% of the twins with AIS reported to have the same or a better health than their twin- and age-matched peers.