Influence of microsurgical decompression on segmental stability of the lumbar spine - One-year results in a prospective, consecutive case series using upright, kinetic-positional MRI.

BACKGROUND: Standard procedure in patients with lumbar spinal canal stenosis is decompression to relieve the neural structures. Clinical results generally show superiority compared to nonoperative therapy after an observation period of several years. However, there is still a question of postsurgical segmental stability and correlation to clinical findings. Therefore, the aim of this prospective study was to evaluate the clinical outcome in patients who underwent microsurgical decompression in lumbar spine and particularly to analyze intervertebral movement by use of upright, kinetic-positional magnetic resonance imaging (MRI) over a period of 12 months and then to correlate the clinical and imaging data with each other. METHODS: Complete clinical data of 24 consecutive participants with microsurgical decompression of the lumbar spine were obtained by questionnaires including visual analogue scale (VAS) for back and leg, Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RMDQ), Short-Form-36 (SF-36), walking distance and use of analgesics with assessment preoperatively and after 6 weeks and 12 months. At the same points of time all patients underwent upright, kinetic-positional MRI to measure intersegmental motion of the operated levels with determination of intervertebral angles and translation and to correlate the clinical and imaging data with each other. RESULTS: VAS for leg, ODI, RMDQ and physical component scale of SF-36 improved statistically significantly without statistically significant differences regarding intersegmental motion and horizontal displacement 6 weeks and 12 months after operation. Regression analysis did not find any linear dependencies between the clinical scores and imaging parameters. CONCLUSIONS: In awareness of some limitations of the study, our results demonstrate no increase of intersegmental movement or even instability after microsurgical decompression of the lumbar spine over a follow-up period of 12 months, which is equivalent to preservation of intervertebral stability. Furthermore, the magnitude of intervertebral range of motion showed no correlation to the clinical score parameters at all three examination points of time.

Erratum: The computed tomography based anatomy of the ossa cuneiformia.

There is a lack of basic anatomic informations regarding the ossa cuneiformia. The aim of the present descriptive study was the detailed evaluation of the anatomy of the ossa cuneiformia. We analyzed 100 computer tomography scans of feet without deformities or previous trauma. The length, height and width of each cuneiforme and their articular surfaces were assessed. We itemized the data to gender differences and to foot length. The medial cuneiforme os had a length of 23.8±2.4 mm (mean ± standard deviation), a width of 15.9±2.7 mm and a height of 26.9±3.6 mm. The respective values for the intermediate cuneiforme were 17.7±1.9 mm, 12.4±3.1 mm and 20.8±2.9 mm and for the lateral cuneiforme 24.3±2.9 mm, 14.9±2.9 mm and 17.3±4.3 mm. We found statistical relevant differences regarding gender and foot length subgroups whereas not for all parameters. The present study illustrates basic anatomic data regarding the ossa cuneiformia. This information might be helpful for implant design and placement during midfoot surgery.

Feasibility and reliability of DEXA analysis after total ankle arthroplasty: A cadaver study.

BACKGROUND: Although the outcomes of total ankle arthroplasty (TAA) have improved, unsolved problems such as stress shielding remain. Although dual energy X-ray absorptiometry (DEXA) is the "gold standard" for evaluation of these issues, it is rarely used in patients after TAA. This study aimed to establish a scan technique and to assess the mechanical changes in bone density caused by bone stock preparation. METHODS: Eight fresh-frozen cadaver legs were investigated by DEXA before TAA, with implant in situ, and after implant removal. Scan surface, bone mineral content, and bone mineral density were analysed to assess mechanical bone mass changes. RESULTS: We examined data for density changes by bone compression after TAA, and found "good" results for internal reliability but only "acceptable" results for external reliability. CONCLUSIONS: The results were reliable and reproducible. Using the present data, mechanical and biological processes can be considered together to understand the postoperative phases of bone remodelling after TAA.

The computed tomographybased anatomy of the ossa cuneiformia.

There is a lack of basic anatomic information regarding the ossa cuneiformia. The aim of the present descriptive study was the detailed evaluation of the anatomy of the ossa cuneiformia. We analyzed 100 computer tomography scans of feet without deformities or previous trauma. The length, height and width of each cuneiforme and their articular surfaces were assessed. We itemized the data to gender differences and to foot length. The medial cuneiforme os had a length of 24.0 mm ± 2.4 (mean ± standard deviation), a width of 17.3 mm ± 2.8 and a height of 28.0 mm ± 3.4. The respective values for the intermediate cuneiforme were 18.2 mm ± 2.1, 15.8 mm ± 2.1 and 22.5 ± 2.2 and for the lateral cuneiforme 26.4 mm ± 2.7, 17.2 mm ± 2.9 and 22.8 mm ± 2.9. We found statistical relevant differences regarding gender and foot length subgroups whereas not for all parameters. The present study illustrates basic anatomic data regarding the ossa cuneiformia. This information might be helpful for implant design and placement during midfoot surgery.