| 1. |
- Knutsson, Björn
(författare)
-
Lumbar spinal stenosis : Body mass index and the patient's perspective
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During recent decades, lumbar spinal stenosis (LSS) has become the most common indication for spine surgery, a change that coincides with a higher worldwide prevalence of overweight and obesity. Thus, surgical treatment of LSS in the overweight and obese population is common and increasing in scope.The overall aim of this thesis was to investigate whether body mass index (BMI) is related to the development of LSS, and whether BMI is linked to outcome after surgery for LSS. We further evaluated whether there are specific experiences of LSS from a patient perspective.Data were obtained for all patients registered in the Swedish Spine Register who had undergone surgery for LSS between January 1, 2006 and June 30, 2008. After adjusting for differences in baseline characteristics, patients with obesity showed both poorer results after surgery and a higher rate of dissatisfaction than patients with normal weight (odds ratio 1.73; 95% confidence interval, CI, 1.36-2.19).Furthermore, patients with obesity in the cohort reported modest weight loss at follow-up (2.0 kg; 95% CI, 1.5-2.4), and only 8% reported a clinical important weight loss 2 years after surgery.Our analysis of 389,132 construction workers, showed that overweight (incidence rate ratio, IRR 1.68; 95% CI, 1.54-1.83) and obesity (IRR 2.18; 95% CI, 1.87-2.53) were associated with an increased future risk in developing LSS when compared with patients with normal weight.To gain insight into the patients' perspective of LSS, we performed interviews with 18 patients who were on a waiting list for LSS surgery. The transcripts, analyzed with content analysis, revealed that living with LSS is a physical, mental and social challenge in which resources to cope with the condition are of major importance.In summary, obesity is associated with poorer results after surgery, and patients with obesity report modest weight loss during follow-up. In addition, obesity is associated with an increased risk to develop LSS. Our findings revealed that being a patient with LSS, naturally involves considerable suffering and pain, but it also implies being a person with his or her own resources who is able to cope with these adverse conditions.
|
|
| 2. |
- Christersson, Albert
(författare)
-
Fractures of the distal radius : Factors related to radiographic evaluation, conservative treatment and fracture healing
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Distal radius fractures (DRFs) are one of the most common injuries encountered in orthopaedic practise. Such fractures are most often treated conservatively, but surgical treatment has become increasingly common. This trend is not entirely scientifically basedThe aims of this thesis were threefold: to increase measurement precision in dorsal angulation (DA) on radiographs and computer tomographies (CTs); to assess the results after shortened plaster cast fixation time in reduced DRFs; and to evaluate the feasibility and safety of applying Augment® (rhPDGF-BB/β-TCP) in DRFs.In Paper I and Appendix 1 and 2, a semi-automatic CT-based three-dimensional method was developed to measure change in DA over time in DRFs. This approach proved to be a better (more sensitive) method than radiography in determining changes in DA in fractures of the distal radius.In Paper II, a CT model was used to simulate lateral radiographic views of different radial directions in relation to the X-ray. Using an alternative reference point on the distal radius, precision and accuracy in measuring DA was increased.Paper III and IV are based on a prospective and randomised clinical study (the GitRa trial) that compares clinical and radiographic outcomes after plaster cast removal at 10 days versus 1 month in 109 reduced DRFs. Three patients in the early mobilised group were excluded because of fracture dislocation (n=2) or a feeling of fracture instability (n=1). For the remaining patients in the early mobilised group (51/54) a limited but temporary gain in range of motion, but a slight increase in radiographic displacement were observed. Our results suggest that plaster cast removal at 10 days after reduction of DRFs is not feasible.Paper V is based on a prospective, randomised clinical study (the GEM trial) in which 40 externally fixated DRFs were randomised to rhPDGF-BB/β-TCP into the fracture gap or to the control group. Augment® proved to be convenient and safe during follow-up (24 weeks). However, because of the nature of the study design, the effect on fracture healing could not be determined. A decrease in pin infections was seen in the Augment® group, a finding we could not explain.
|
|
| 3. |
- Sandén, Bengt
(författare)
-
Fixation of Spinal Implants : Clinical and Experimental Studies on the Effects of Hydroxyapatite Coating
- 2001
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Loosening of implants is a frequent complication in orthopaedic surgery. The aim of this thesis was to evaluate hydroxyapatite coating of pedicle screws with mechanical and histological methods and to correlate the results with the radiological findings.Hydroxyapatite (HA) coating of pedicle screws was investigated in experimental studies in sheep. Nine sheep were operated on with destabilising laminectomies at L2-L3 and L4-L5 and stabilised with pedicle screw instrumentations, where HA coated and uncoated screws were used in a randomised fashion. After both 6 and 12 weeks of implantation, the HA coated screws demonstrated a higher bone-to-implant contact and a higher amount of bone in the area close to the screw. The pull-out resistance, stiffness and total energy to failure was higher for the HA coated screws after 12 weeks of implantation.HA coating of pedicle screws was examined in two clinical studies. In the first series, the patients were stabilised with pedicle screw instrumentations, where HA coated screws were used in either the upper or lower instrumented level in a randomised fashion. After 10-22 months of implantation, the extraction torque was markedly higher for the HA coated screws. In the second series, instrumentations with uncoated, partly HA coated or fully HA coated screws were used. After 11-16 months implantation, the extraction torques were recorded. There were significant differences between all three groups, with the lowest extraction torques for the uncoated screws and the highest torques for the fully HA coated screws. The frequency of radiolucent zones surrounding the screws was higher for the uncoated screws than for the HA coated screws.Radiographs from both experimental and clinical studies were examined. Screws demonstrating radiolucent zones were compared to screws without zones with respect to pull-out resistance, extraction torque, bone-to-implant contact and amount of bone surrounding the screws. All these variables demonstrated higher values for the screws without radiolucent zones. The frequency of radiolucent zones surrounding uncoated screws in the clinical study was 53%.Conclusions: Radiolucent zones are good predictors of screw loosening. The frequency of radiolucent zones is higher than previously described. Hydroxyapatite coating improves the purchase of pedicle screws and reduces the frequency of screw loosening.
|
|
