Introduction: Obesity is often considered as a risk-factor for higher complication rates and worse clinical outcome of fusion surgery in the lumbar spine and is therefore sometimes not performed in obese patients despite relative indication for surgery. The goal of this study was to evaluate whether BMI is a predictive factor for clinical outcome after monosegmental fusion surgery in the lumbar spine.

Patients and Methods: The present study is a retrospective analysis of prospectively collected data in a consecutive series of patients.

Between April 2002 and April 2007, a total of 467 patients underwent monosegmental lumbar fusion in a single spine-center. Preoperatively and at 6 weeks and 1 year follow-up, SF36 and Oswestry-Disability-Index scores were collected. We excluded patients who underwent surgery due to infections, tumor and trauma, as well as revision surgeries, and all patients with incomplete datasets, so that 223 patients were included in the study. Of those patients, variables considered as risk-factors like age, BMI and the presence of diabetes mellitus were assessed from the medical records. A multiple regression model for those parameters and clinical outcome was cretated. Results: In an unadjusted model, BMI did not at all predict clinical outcome, in a multivariate model adjusted for baseline outcome values of SF36, Oswestry-Disability index and age, a slight trend towards negative correlation between BMI and outcome could be shown (p=0.06).

Conclusion: This study suggests that BMI alone is not a good predictor of clinical outcome of monosegmental lumbar fusion and that therefore this kind of surgery should not be withheld from patients only because of obesity.

Since total disc replacement (TDR) has broadened the spectrum of surgical treatment of degenerative spine diseases many comparison studies, particularly with interbody fusions (IF), have been done. Even though comparable results concerning functionality, radiologic results and subjective rating of life-quality have been presented, very few data about athletic activity before and after spine surgery exists.

Material and Methods: Between 1/2002 and 10/2006 181 patients had interbody fusions and 57 had a total disc replacement. Of 86 IF-patients and 25 patients with TDR we have complete data, which was collected in pre- and postoperative clinic and radiologic routine control with standardised questionnaires containing evaluation of level (frequency) and sort of sport. Patients are matched according to demographic data and preoperative activity beside the most important match of operation method.

Results: Patients with Total disc replacement show a later resumption of sports (19 weeks) than fusion patients (14 weeks), but more TDR patients (60%) achieve their preoperative level of sport than IF-patients (36%) do. Vice versa to the Fusion group in the TDR group more patients start a new sport after surgery than to stop one. Percentage of patients doing sports post- compared to preoperative is higher in both groups. Less patients having a TDR complain about technical limitations during practicing sports than fusion patients.

Discussion: Despite later resumption of athletic activity TDR seems to be the better surgical treatment of degenerative disc diseases in active patients and athletes due to overall higher sports levels. If long term results can keep up with short time follow ups has to be questioned.

Operative treatment of osteoporotic vertebral fractures seems to result in higher primary costs compared to conservative treatment. However it is still unclear whether the inpatient related follow-up costs don’t result in a different outcome.

The aim of this analysis was a nationwide comparison of spine related inpatient treatments after balloon kyphoplasty versus conservative treatment of balloon kyphoplasty patients.

Materials and Methods: 110 patients after conservative treatment and 141 patients after balloon kyphoplasty treated primarily between 2002 and 2005 in one center were followed up via a nationwide analysis of spine related inhospital treatment.

Data from the Austrian DRG-system, which includes all inpatients treated in Austria have been used to identify admission of the target population between 2002 and 2006. Because no unique patient identifier is available in the data set, a matching according to data of birth, gender and postal code was used. Outpatient visits are not included. From these data the number of admissions, the length of stay and the scores can be determined. Furthermore each admission was classified as spine related or not.

To calculate the exact follow up times the data were matched against the Austrian death registry. If a patient has died this data was used to calculate the follow up time otherwise December 31st 2006 was used.

The mean age of the conservative group was 75.49 and of the kyphoplasty group 71.16 years.

The total follow up time was 324.55 years(mean +standard deviation 2.92+−1.40) for the conservative and 354.25 (2.53+−0.96) for the kyphoplasty group. The shorter mean follow up interval for the kyphoplasty group is due to the fact that in the years 2004 and 2005 more patients have been treated by kyphoplasty.

Results: The mean number of admissions in the kyphoplasty group is 0.779 or 0.308 per follow up year whereas in the conservative group these figures are approximately twice, namely 1.757 and 0.601. Considering the average length of stay the kyphoplasty group shows less inhospital days (9.2 per patient or 3.6 per follow up year), whereas in the conservative group this is 14.4 and 4.6 inpatient days. Finally the scores per admission in the follow up period are lower in the kyphoplasty group (3146 and 1243 DRG related treatment points) whereas in the conservative group these values are 3824 and 1308.

Conclusion: These data show a strong superiority of kyphoplasty compared to conservative treatment of spine problems based on the data of one big hospital in Austria where 251 patients have been treated between 2002 and 2005.

We demonstrate a long term superiority of balloon kyphoplasty compared to non-surgical treatment regarding inpatient treatments.

Kyphoplasty is an efficient tool in the treatment of primary tumours (plasmocytoma) and osteolytic metastasis. Especially in plasmocytoma the current chemotherapy has increased life expectancy significantly. Therefore minimal-invasive stabilisation is not only a palliative treatment but really increases quality of life in those cases.

Kyphoplasty offers several special tools and techniques to lower the leakage rate which is especially high with other cementoplasty techniques in the osteolytic spine.

Materials and Methods: Prospective study of all vertebral tumours compared to osteoporotic fractures treated with kyphoplasty in 2004. 6 months follow up with VAS, SF36 and Oswestry score.

Results: In 2004 we performed 67 Kyphoplasties. 12 kyphoplasties were performed in tumour cases (5 plasmocytoma and 7 metastasis). No complications occurred during surgery and during hospital stay. Follow-up included 11 tumours (1 death during F/U) and 46 osteoporotic fractures. 1 patient was treated with combined decompression/kyphoplasty. The pain level (VAS) was significantly reduced in all cases within 2 days (osteoporotic group 2,2 – tumour group 5,4) and reached nearly the same result after 6 weeks which persisted for 6 months (osteoporotic group 1,6, tumour group 2,1). The SF 36/Oswestry Score improved accordingly in both groups. At 6 weeks and 6 months F/U no statistical difference in the scores was seen.

Conclusion: Kyphoplasty is a safe treatment method for osteolytic vertebral tumours with vertebral collapse. Clinically the results don’t differ from conventional cases. In cases with canal compromise, a combination with open techniques is possible. Special kyphoplasty techniques allow a reconstruction of the lytic wall and minimise leakage and cement dislocation. Significant improvement of life quality can be achieved offering the spine surgeon a valuable tool in the treatment of spinal metastasis.

Purpose: After vertebroplasty and kyphoplasty the recurrent fracture risk after kyphoplasty is inferior to vertebroplasty, but the risk is still eminent. The reduction of kyphosis is strongly related to the age of the fracture, therefore the reduction and the correction of the kyphosis varies. We investigated the indication of a prophylactic kyphoplasty of adjacent levels to the fracture site in order to decrease the postoperative refracture risk.

Methods: Prospective randomized clinical study, 2 groups: monosegmental kyphoplasty versus bi- or mul-tisegmental kyphoplasty with prophylactic level superior to the fracture. F/U 6 months with X-rays.

Results: Group 1: monosegmental stabilization: (23 pat. 4 male, 19 female, 23 levels). 5 refractures. 3 refractures adjacent to the kyphoplasty, 2 cases not related to the primary stabilization. In 3 cases cement leakage was seen as direct cause of the refracture. |Group 2: pro-phylactic stabilization (27 pat. - 4 male, 23 female, 27 prophylactic levels). 7 refractures, all adjacent to kypho-plasty. In 3 cases cement leakage as cause of recurrent fracture. No statistical difference between both groups was found, however in 6 out of 12 recurrent fractures we found intradiscal cement leakage as the direct cause of the fracture.|

Conclusions: No statistical difference between both groups (group 1: 22% refracture risk, group 2: 26% refracture risk, p=1). Therefore we do not see the need for a generalized prophylactic stabilization of adjacent levels with kyphoplasty. However, we conclude that it is crucial to avoid any leakage, which has a direct impact on the fracture rate, only in those cases we advise a prophylactic stabilization at the leakage site. In general kyphoplasty is preferable to vertebroplasty due to generally decreased leakage and embolism rate.

Purpose: A complete collapse of osteoporotic vertebral fractures is difficult to treat. Restoration of vertebral height is very difficult, if ever possible. Kyphoplasty has been shown to restore vertebral compression fractures; however the best results are achieved in fractures without total collapse. Nevertheless some fractures develop osteonecrosis and pseudarthosis which can be easily seen on X-ray. For those cases we performed a retrospective study in order to evaluate the capacity of kyphoplasty in those difficult situations.

Methods: We analyzed the pre- and postoperative X-rays of vertebra plana treated between 2002 and 2005. Vertebral height (vh -anterior, middle and posterior) and kyphotic angle were measured with a digital imaging system. 2 independent examiners classified the preoperative X-rays into fractures with osteonecrosis/pseud-arthrosis (group 1) and without osteonecrosis (group 2). Statistical analysis with the non-parametric Mann-Whitney test was performed.

Results: Between 2002 and 2005 we performed 315 kyphoplasties. A total collapse of the vertebra (vertebra plana) was treated in 15 cases. Mean age 76 years, SD 5.2 years, average time of treatment after fracture 4 months. Osteonecrosis was persistent in 8 cases. The osteonecrosis group found a statistically significant higher degree of vertebral reconstruction (p < 0.013 - group 1: anterior vh 33%, middle vh 37,8%, posterior vh 19,1%; group 2: anterior vh 4,9%, middle vh 17,5%, posterior vh 1,8%). No significant difference was found in the analysis of the pre- and postop. kyphotic angle which could be due to the small sample size as the mean values are three-fold elevated in group 1 (p = 0.146, group 1: restoration mean 9,1° - maximum 18°; group 2: restoration mean 3,5° - maximum 13°).

Conclusions: Osteonecrosis is a positive predictive sign for the potential of vertebral reconstruction. Vertebral height can be significantly improved in those patients and the major changes of the kyphotic angle are possible. Even after 4 months, correction of the deformity is possible with kyphoplasty. However, without this sign, restoration of the vertebral height and correction of kyphosis is limited to rare cases.

Recurrent fracture risk after kyphoplasty is inferior to vertebroplasty, but the risk is still eminent. The reduction of kyphosis is strongly related to the age of the fracture, therefore the reduction and the correction of the kyphosis varies. We investigated the indication of a prophylactic kyphoplasty of adjacent levels to the fracture site in order to decrease the postoperative refracture risk.

Study design: Prospective randomized clinical study, 2 groups: monosegmental kyphoplasty versus bi- or multi-segmental kyphoplasty with prophylactic level superior to the fracture. F/U 6 months with X-rays

Results: Group 1: monosegmental stabilisation: (20 pat. 4 male, 16 female, 27 levels). 5 refractures. 3 refractures adjacent to the kyphoplasty, 2 cases not related to the primary stabilisation.

In 2 cases cement leakage was seen as direct cause of the refracture.

Group 2: prophylactic stabilisation (28 pat. 4 male, 24 female, 63 levels, 29 prophylactic levels). 8 refractures, all adjacent to kyphoplasty. In 3 cases cement leakage as cause of recurrent fracture.

Conclusion: Refracture rates are in both groups similar (group 1: 25% refracture risk, group 2: 28% refracture risk). Therefore we do not see the need for a generalised prophylactic stabilisation of adjacent levels with kyphoplasty. It is crucial to avoid any leakage, which has a direct impact on the fracture rate, only in those cases we advise a prophylactic stabilisation at the leakage site. In general kyphoplasty is preferable to vertebroplasty due to the decreased leakage and embolism rate.

Objective: To compare multi surgeon reliability of the classification systems of H. A. King and R.W. Coonrad and to analyse controversial classified curve patterns.

Design: Three scoliosis surgeons and one orthopedic fellow were presented the AP radiographs of seventy adolescent idiopathic scoliosis patients. All reviewers assigned a type to each curve according to the classification systems of H. A. King [1] and R. W. Coonrad [2].

Subjects: Interobserver agreement and intraobserver reproducibility were tested. Kappa coefficients were used to test reliability. Between the observers, the divergent assignments to curve patterns were analysed in quantitative as well as in qualitative terms. An error analysis was performed.

Results: For King’s classification, paired comparisons revealed a mean interobserver kappa coefficient of 0.45, and for Coonrad’s classification system 0.38, respectively. According to Svanholm et al., these values indicate poor reliability in terms of interobserver agreement. Error analyses for both classification systems revealed that the reason for poor reproducibility is disagreement on structural upper thoracic and structural lumbar curves among the observers.

Conclusion: Neither King’s nor Coonrad’s method appear to have sufficient interobserver reliabilty. In order to improve reliability we recommend unequivocal description of structural stigmata of upper thoracic and lumbar curves.

Instruments used in surgery which rotate or vibrate at a high frequency can produce potentially contaminated aerosols. Such tools are in use in cemented hip revision arthroplasties. We aimed to measure the extent of the environmental and body contamination caused by an ultrasound device and a high-speed cutter.

On a human cadaver we carried out a complete surgical procedure including draping and simulated blood flow contaminated with Staphylococcus aureus (ATCC 12600). After cemented total hip arthroplasty, we undertook repeated extractions of cement using either an ultrasound device or a high-speed cutter. Surveillance cultures detected any environmental and body contamination of the surgical team.

Environmental contamination was present in an area of 6 x 8 m for both devices. The concentration of contamination was lower for the ultrasound device. Both the ultrasound and the high-speed cutter contaminated all members of the surgical team. The devices tested produced aerosols which covered the whole operating theatre and all personnel present during the procedure. In contaminated and infected patients, infectious agents may be present in these aerosols. We therefore recommend the introduction of effective measures to control infection and thorough disinfection of the operating theatre after such procedures.

We report a prospective, stratified study of 60 PCA-cups and 60 RM-polyethylene cups which have been followed for a median time of 90 months, with annual radiography.

The radiological migration of cups was measured by the computer-assisted EBRA method. A number of threshold migration rates from 1 mm in the first year to 1 mm in five years have been assessed and related to clinically determined revision rates. A total of 28 cups showed a total migration of 1 mm or more within the first two years; 13 of these cups have required revision and been exchanged.

The survival curves of cups which had previously shown early migration were considerably different from those without early migration. For cups with a migration of less than 1 mm within the first two years the mean survival at 96 months was 0.96 ± 0.02; for migrating cups, it was 0.63 ± 0.11 (log-rank test, p = 0.0001; chi-square value = 39.4).

Early migration is a good predictor for late loosening of hip sockets.