Biomedical subjects

Daniel Chopin

Publications and source records attributed to Daniel Chopin.

5 recordsLinked to original sources

PubMed2006

Clinical, radiological and histological study of the failure of cervical interbody fusions with bone substitutes.

Few histological studies on bone substitutes in human cervical spine are available and the biological processes of bone substitutes are not well documented. The authors studied four failure cases of cervical interbody fusion: two cases with hydroxyapatite (HA), one case with beta-tricalcium phosphate ceramic (beta-TCP) and one case with xenograft (bovine bone). Clinical data showed that all the patients experienced neck pain with or without numbness of upper extremity due to fusion failure. Successful fusions were achieved after the salvage surgeries in which autograft were used. Radiographs showed that radiolucent lines were present in all cases. Two HA substitutes fractured without complications. One of them sank into the vertebral body. Some small beta-TCP fragments were found under the microscope. Histological study demonstrated only a few newly formed bones at the interface of the substitutes. The fragments of HA were encapsulated by fibrous tissue. The degradation process and bone regeneration were more active in beta-TCP than in HA. The intertrabecular spaces of bovine bone were filled with fibrous tissue. The results suggest that a porous calcium phosphate ceramic with special design might assure bone ingrowth and meet the mechanical requirements in cervical interbody fusion. The complications of these materials in the cervical spine should be highlighted.

Adult↗

PubMed2006

Evaluation of the osteogenesis and biodegradation of porous biphasic ceramic in the human spine.

The histological reports on porous biphasic calcium phosphate ceramic (PBC) in human spine are limited. The osteogenesis and biodegradation of PBC are insufficiently known in human. In present study, the undecalcified histological study was carried out on 20 samples retrieved from posterior spinal fusion in order to reveal the osteogenesis and biodegradation of the PBC in human spine. The quantitative study was performed in 14 samples with sufficient size. Newly formed bone was found in all the samples. More new bone was formed in those samples closely in contact with autogenous bone. The PBC degradation particles were present both in the macrophages and around the tissue. However, those phenomena were highly variable among the samples. New bone formation increased with time and decreased with age. The PBC degradation decreased with age, but it did not differ greatly with time. New bone formation was higher and the residual material was lower in the fusion group than that in non-fusion group. The PBC is a kind of osteoconductive material and do not transform into new bone after a relatively long time. The PBC should be well mixed with the autogenous bone in order to achieve high new bone colonization. The PBC degradation particles and related active phagocytotic activity have been noted.

Absorbable Implants↗

PubMed2005

Long-term results of Schollner costoplasty in patients with idiopathic scoliosis.

STUDY DESIGN: A retrospective analysis of patients with idiopathic scoliosis treated with Schollner costoplasty. OBJECTIVE: To evaluate the long-term effects of Schollner costoplasty on rib hump and respiratory function SUMMARY BACKGROUND DATA: Costoplasty is an established technique to improve chest wall deformity in patients with scoliosis. Concerns have been raised of the long-term effects of costoplasty on respiratory function in adults. No long-term studies of this procedure exist. METHODS: A total of 25 patients with idiopathic scoliosis rib hump deformity underwent Schollner costoplasty. There were 12 patients who underwent surgery on the convexity alone, and 13 underwent additional "concave surgery" (6 Silastic [Dow Corning Corp., Midland, MI] implants, 7 concave lengthenings). Five patients underwent simultaneous spinal arthrodesis. The remaining patients underwent delayed procedures (0.4 -19 years) following the index operation. Vital capacity (VC) and rib hump were measured before and after surgery, and at each attendance thereafter. RESULTS: Mean follow-up was 10.8 years. Average reduction in rib hump was 38 mm at 6 months and 29 mm at long-term. There was no significant difference in the preoperative and long-term VC (P = 0.4), although at 6 months after surgery, there was a significant reduction in VC of 5.1%(P = 0.03). Subgroup analysis (convex only, concave lengthening, concave Silastic) revealed a similar pattern for rib hump correction and maintenance of VC in the long-term for each group. There was no significant difference between adults and adolescents in terms of both the reduction in rib hump and the VC (P = 0.2 and 0.3) CONCLUSIONS: Rib hump correction and lung function are preserved in the long-term following Schollner costoplasty in both adults and adolescents.

Adolescent↗

PubMed2004

Spondylolisthesis, pelvic incidence, and spinopelvic balance: a correlation study.

STUDY DESIGN: A retrospective study of the sagittal alignment in developmental spondylolisthesis. OBJECTIVES: To investigate the role of pelvic anatomy and its effect on the global balance of the trunk in developmental spondylolisthesis. SUMMARY OF BACKGROUND DATA: Pelvic incidence (PI) is a fundamental anatomic parameter that is specific and constant for each individual, and independent of the three-dimensional orientation of the pelvis. Recent studies have suggested an association between a high PI and patients with isthmic spondylolisthesis. METHODS: The lateral standing radiographs of the spine and pelvis of 214 subjects with developmental L5-S1 spondylolisthesis were analyzed with a dedicated software allowing the calculation of the following parameters: pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL), thoracic kyphosis (TK), and grade of spondylolisthesis. All measurements were done by the same individual and compared to those of a cohort of 160 normal subjects. Student's tests were used to compare the parameters between the curve types and Pearson's correlation coefficients were used to investigate the association between all parameters (alpha = 0.01). RESULTS: PI, SS, PT, and LL are significantly greater (P < 0.01) in subjects with spondylolisthesis, while TK is significantly decreased. PI has a direct linear correlation (0.41-0.65) with SS, PT, and LL. Furthermore, the differences between the two populations increase in a direct linear fashion as the severity of the spondylolisthesis increases. CONCLUSIONS: Since PI is a constant anatomic pelvic variable specific to each individual and strongly determines SS, PT, and LL, which are position-dependent variables, this study suggests that pelvic anatomy has a direct influence on the development of a spondylolisthesis.Study participants with an increased pelvic incidence appear to be at higher risk of presenting a spondylolisthesis, and an increased PI may be an important factor predisposing to progression in developmental spondylolisthesis.

Adolescent↗

PubMed2002

Kyphoplasty.

A variant of vertebroplasty known as "kyphoplasty" has been suggested for correcting vertebral compression fractures. A balloon placed inside the vertebral body is inflated to create a cavity, thereby restoring vertebral body height and allowing low-pressure cement injection. This procedure is gaining popularity in the United States. Over 1000 patients had been treated by the end of 2000. However, kyphoplasty is costly (chiefly because the balloon is disposable) and has not been evaluated in carefully designed studies. Although retrospective findings have been reported as highly promising, they are not sufficient to validate this procedure. The principle is innovative and the procedure deserves further investigation as a potentially effective means of correcting loss of vertebral height. Furthermore, use of a bone substitute instead of cement deserves investigation.

Humans↗