Home About us Contact
|
Home About us Contact | ||
|
|
||
L5 Level (l5 + level)
Selected AbstractsEnhancement of posterolateral lumbar spine fusion using low-dose rhBMP-2 and cultured marrow stromal cellsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2009Tsai-Sheng Fu Abstract We tested the hypothesis that the dose of recombinant human bone morphogenetic protein-2 (rhBMP-2) required to induce spine fusion can be reduced by combination with mesenchymal stem cells (MSCs). Twenty-four adult rabbits underwent posterolateral intertransverse fusion at the L4,L5 level. The animals were divided into four groups based on the implant material: autologous iliac graft, Alginate-MSCs composite, Alginate-BMP-2-MSCs composite, and Alginate-BMP-2 composite. After 16 weeks, the rabbits were euthanized for radiographic examination, manual palpation, biomechanical testing, and histology. Radiographic union of 12 intertransverse fusion areas for the autogenous iliac graft, Alginate-MSCs, Alginate-BMP-2-MSCs, and Alginate-BMP-2 groups was 11, 8, 11, and 0, respectively. Moreover, manual palpation of six fusion segments in each subgroup found solid union to be 6, 1, 5, and 0, respectively. The average torques at failure of the first three groups were 2278,±,135, 1943,±,140, and 2334,±,187 N-mm, respectively. The failure torque did not differ significantly between the autograft and Alginate-BMP-2-MSCs groups; both groups were significantly higher than the Alginate-MSCs group. The results indicate that MSCs delivered with in vitro cellular doses of rhBMP-2 are more osteoinductive than MSCs without rhBMP-2. In combination with MSCs, a low dose (2.5 µg) of rh-BMP-2 could enhance bone formation and posterolateral spine fusion success in the rabbit model. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:380,384, 2009 [source] The Surgical Anatomy of Lumbar Medial Branch Neurotomy (Facet Denervation)PAIN MEDICINE, Issue 3 2004Peter Lau FRACR ABSTRACT Objective., To demonstrate the validity of placing electrodes parallel to the target nerve in lumbar radiofrequency neurotomy. DESIGN., Previous data on the anatomy of the lumbar dorsal rami were reviewed and a demonstration cadaver was prepared. Under direct vision, electrodes were placed on, and parallel to, the L4 medial branch and the L5 dorsal ramus. Photographs were taken to record the placement, and radiographs were taken to illustrate the orientation and location of the electrode in relation to bony landmarks. Results., In order to lie in contact with, and parallel to, the target nerve, electrodes need to be inserted obliquely from below, so that their active tip crosses the neck of the superior articular process. At typical lumbar levels, the tip should lie opposite the middle two quarters of the superior articular process. At the L5 level, it should lie opposite the middle and posterior thirds of the S1 superior articular process. Conclusion., If electrodes are placed parallel to the target nerve, the lesions made can be expected to encompass the target nerves. If electrodes are placed perpendicular to the nerve, the nerve may escape coagulation, or be only partially coagulated. Placing the electrode parallel to the nerve has a demonstrated anatomical basis, and has been vindicated clinically. Other techniques lack such a basis, and have not been vindicated clinically. Suboptimal techniques may underlie suboptimal outcomes from lumbar medial branch neurotomy. [source] Lumbar vertebral morphology and isthmic spondylolysis in a British medieval populationAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Carol V. Ward Abstract The British medieval population from Wharram Percy, England, has a greater prevalence of isthmic spondylolysis (11.9% of skeletons, 8.5% at the L5 level) than in modern populations (3%,6%). This may in part be due to differences in activity patterns between groups. However, Ward and Latimer (Spine 30 [2005] 1808,1814) proposed that the likelihood of developing and maintaining spondylolytic defects is also influenced by a lack of sufficient increase in mediolateral separation between articular processes in the lowest lumbar segments, given the human lumbar lordosis. Here, we demonstrate that spondylolytic individuals from Wharram Percy tend to have a less pronounced difference between mediolateral facet joint spacing of adjacent segments in the lowest lumbar region than do unaffected individuals, as seen in modern clinical and skeletal populations. These comparisons suggest that regardless of lifestyle, insufficient mediolateral increase in facet spacing predisposes people to spondylolytic defects, and so interfacet spacing patterns may have predictive utility in a clinical context. We also compare the Wharram Percy sample to a modern sample from the Hamann Todd collection with a typically modern prevalence rate. Data do not support the hypothesis that the Wharram Percy individuals had a less pronounced interfacet increase than the Hamann Todd, although they do have narrower lumbar facet spacing at the lowest three levels. Further investigation of anatomical variation underlying population-specific prevalence rates needs to be conducted. Am J Phys Anthropol 2010. © 2009 Wiley-Liss, Inc. [source] Pedicle dimensions of the thoracic and lumbar vertebrae in the Greek population,,CLINICAL ANATOMY, Issue 6 2005Anastasios G. Christodoulou Abstract The aim of this study is to understand the magnitude of the pedicle's diameters for the use of pedicle screw fixation in spinal instrumentation. Pedicle dimensions from T1 to L5 were measured in 16 whole human cadaver spines (eight women and eight men). The mean age at the time of death was 67.2 (range: 59,84 years). The external transverse, the external sagittal, and the internal transverse diameter pedicle widths were measured with electronic calipers both on the right and left pedicles. The widest external transverse diameter was at the L5 level with a mean of 13.61 mm (range: 10.29,16.20 mm). The narrowest external transverse pedicle diameter was at the T5 level with a mean of 5.09 mm (range: 4.10,6.88 mm). The widest external sagittal pedicle diameter was at the T11 level with a mean of 17.02 mm (range: 14.84,19.57 mm), while the narrowest one was at T1 level with a mean of 8.90 mm (range: 7.18,11.37 mm). The maximum internal transverse pedicle diameter was at the L5 level with a mean 8.95 mm (range: 7.10,11.21 mm), while the minimum was at the T5 level with a mean 3.90 mm (range: 3.10,4.82 mm). Statistical significant greater pedicle dimensions were found in males at multiple levels. Pedicle dimensions at the levels from T3 to T8 need preoperative evaluation with computed tomography before the insertion of pedicle screws with diameter more than 5 mm. Pedicles at T12 to L5 levels may accommodate screws of 7 mm diameter. Clin. Anat. 18:404,408, 2005. © 2005 Wiley-Liss, Inc. [source] | ||||||||||