The aims of this study were first, to determine if adding fusion to a decompression of the lumbar spine for spinal stenosis decreases the rate of radiological restenosis and/or proximal adjacent level stenosis two years after surgery, and second, to evaluate the change in vertebral slip two years after surgery with and without fusion. The Swedish Spinal Stenosis Study (SSSS) was conducted between 2006 and 2012 at five public and two private hospitals. Six centres participated in this two-year MRI follow-up. We randomized 222 patients with central lumbar spinal stenosis at one or two adjacent levels into two groups, decompression alone and decompression with fusion. The presence or absence of a preoperative spondylolisthesis was noted. A new stenosis on two-year MRI was used as the primary outcome, defined as a dural sac cross-sectional area ≤ 75 mm2 at the operated level (restenosis) and/or at the level above (proximal adjacent level stenosis).Aims
Methods
Whether to combine spinal decompression with
fusion in patients with symptomatic lumbar spinal stenosis remains
controversial. We performed a cohort study to determine the effect
of the addition of fusion in terms of patient satisfaction after
decompressive spinal surgery in patients with and without a degenerative spondylolisthesis. The National Swedish Register for Spine Surgery (Swespine) was
used for the study. Data were obtained for all patients in the register
who underwent surgery for stenosis on one or two adjacent lumbar
levels. A total of 5390 patients fulfilled the inclusion criteria
and completed a two-year follow-up. Using multivariable models the
results of 4259 patients who underwent decompression alone were
compared with those of 1131 who underwent decompression and fusion.
The consequence of having an associated spondylolisthesis in the
operated segments pre-operatively was also considered. At two years there was no significant difference in patient satisfaction
between the two treatment groups for any of the outcome measures,
regardless of the presence of a pre-operative spondylolisthesis.
Moreover, the proportion of patients who required subsequent further
lumbar surgery was also similar in the two groups. In this large cohort the addition of fusion to decompression
was not associated with an improved outcome. Cite this article:
We examined the radiographs from a prospective clinical study of fixation by pedicle screws and those from an experimental study in a sheep model. In the clinical study, instruments were removed from 21 patients after implantation for 11 to 16 months and the extraction torques of the screws were recorded. A structured protocol was used for the radiological examinations. In the experimental study, loaded pedicle screw instrumentations were implanted in the sheep for six or 12 weeks. After radiological examination the pull-out resistance and the histological characteristics were studied. In the clinical study, all screws with radiolucent zones had a significantly reduced mean extraction torque compared with screws without radiolucent zones (16 ± 10 Ncm Our findings showed that all screws with radiolucent zones had low extraction torques or low pull-out resistance. A radiolucent zone is a good indicator of loosening of a pedicle screw.
We carried out a randomised, prospective, multicentre clinical trial of the treatment of Colles’ fractures. A total of 339 patients was placed into two groups, those with minimally displaced fractures not requiring manipulation (151 patients) and those with displaced fractures which needed manipulation (188 patients). Treatment was by either a conventional Colles’ plaster cast (a control group) or with a prefabricated functional brace (the Aberdeen Colles’ fracture brace). Similar results were obtained in both groups with regard to the reduction and to pain scores but the brace provided better grip strength in the early stages of treatment. This was statistically significant after five weeks for both manipulated and non-manipulated fractures. At the tenth day the results were statistically significant only in manipulated fractures. There was no significant difference in the functional outcome between the two treatment groups. However, younger patients and those with less initial displacement had better functional results.
We investigated the effects of hydroxyapatite (HA) coating on the purchase of pedicle screws. A total of 23 consecutive patients undergoing lumbar fusion was randomly assigned to one of three treatment groups. The first received uncoated stainless-steel screws, the second screws which were partly coated with HA, and the third screws which were fully coated. The insertion torque was recorded. After 11 to 16 months, 21 screws had been extracted. The extraction torque was recorded. Radiographs were taken to assess fusion and to detect loosening of the screws. At removal, the extraction torques exceeded the upper limit of the torque wrench (600 Ncm) for many HA-coated screws. The calculated mean extraction torque was 29 ± 36 Ncm for the uncoated group, 447 ± 114 Ncm for the partly-coated group and 574 ± 52 Ncm for the fully-coated group. There were significant differences between all three groups (p <
0.001). There were more radiolucent zones surrounding the uncoated screws than the HA-coated screws (p <
0.001). HA coating of pedicle screws resulted in improved fixation with reduced risk of loosening of the screws.
