The effect of starting point placement technique on thoracic transverse process strength: an ex vivo biomechanical study

<p>Abstract</p> <p>Background</p> <p>The use of thoracic pedicle screws in spinal deformity, trauma, and tumor reconstruction is becoming more common. Unsuccessful screw placement may require salvage techniques utilizing transverse process hooks. The effect of different starting point placement techniques on the strength of the transverse process has not previously been reported. The purpose of this paper is to determine the biomechanical properties of the thoracic transverse process following various pedicle screw starting point placement techniques.</p> <p>Methods</p> <p>Forty-seven fresh-frozen human cadaveric thoracic vertebrae from T2 to T9 were disarticulated and matched by bone mineral density (BMD) and transverse process (TP) cross-sectional area. Specimens were randomized to one of four groups: A, control, and three others based on thoracic pedicle screw placement technique; B, straightforward; C, funnel; and D, in-out-in. Initial cortical bone removal for pedicle screw placement was made using a burr at the location on the transverse process or transverse process-laminar junction as published in the original description of each technique. The transverse process was tested measuring load-to-failure simulating a hook in compression mode. Analysis of covariance and Pearson correlation coefficients were used to examine the data.</p> <p>Results</p> <p>Technique was a significant predictor of load-to-failure (<it>P </it>= 0.0007). The least squares mean (LS mean) load-to-failure of group A (control) was 377 N, group B (straightforward) 355 N, group C (funnel) 229 N, and group D (in-out-in) 301 N. Significant differences were noted between groups A and C, A and D, B and C, and C and D. BMD (0.925 g/cm²[range, 0.624-1.301 g/cm²]) was also a significant predictor of load-to-failure, for all specimens grouped together (<it>P </it>< 0.0001) and for each technique (<it>P <</it>0.05). Level and side tested were not found to significantly correlate with load-to-failure.</p> <p>Conclusions</p> <p>The residual coronal plane compressive strength of the thoracic transverse process is dependent upon the screw starting point placement technique. The funnel technique significantly weakens transverse processes as compared to the straightforward technique, which does not significantly weaken the transverse process. It is also dependent upon bone mineral density, and low failure loads even in some control specimens suggest limited usefulness of the transverse process for axial compression loading in the osteoporotic thoracic spine.</p

The effects of ageing on brain tissue sialic acid contents following cold trauma

Background. There is a prominent difference between the responses of young and aged patients to brain injury in the clinical setting, but the exact cause of this condition is not well known

Intraradicular lumbar disc herniation: report of two cases

Study Design: A case report

Polyostotic monosystemic calvarial and spinal Langerhans' cell histiocytosis treated by surgery and chemotherapy

There are several treatment modalities for Langerhans' cell histiocytosis (LCH) of bone, formerly usually referred to as eosinophilic granuloma, including surgery, radiotherapy and chemotherapy. In spinal lesions, surgery is not recommended generally, because of the potential for reconstitution of vertebral height. We report a case of multifocal monosystemic LCH treated by surgery and chemotherapy for calvarial and spinal lesions. A 7-year-old boy was initially operated for an occipital monostotic LCH of bone. Then, he was treated by surgery for cervical and thoracic lesions, and by chemotherapy with vinblastine. The patient had no complaints at the 24-month follow-up. Although surgery is not recommended for spinal lesions in children with LCH of bone, short segmental fusion and internal fixation may be a suitable choice for selected cases, especially in children who are not likely to comply with activity restrictions and in those who it is difficult to follow up. The treatment must be planned according to the characteristics of the patient. Copyright (C) 2003 S. KargerAG, Basel

Biomechanical analysis of cervical multilevel oblique corpectomy: an in vitro study in sheep

Background. Anterolateral oblique corpectomy is an alternative approach to treatment of multilevel cervical spinal disease. It is stated that the approach does not cause instability in the patients with hard discs, so fusion or instrumentation is not required. The authors undertook a study on stability of the cervical spine by an animal model to establish if this approach causes instability

Vertebral osteoid osteoma associated with paravertebral soft-tissue changes on magnetic resonance imaging - Report of two cases

Soft-tissue changes associated with osteoid osteoma have been described in the digits of the hands and feet as well as the long bones. Only six cases in which Such changes Occurred in the spine have been reported. Magnetic resonance (MR) imaging facilitates the determination of such changes. Establishing a diagnosis, however, is especially difficult in spinal osteoid osteoma when using MR imaging. Therefore, osteoid osteoma-related soft-tissue changes demonstrated on MR imaging raise the question of malignancy and may lead to unnecessary long-term treatment or biopsy sampling. The authors report two cases of spinal osteoid osteoma in which paravertebral soft-tissue changes were observed on MR imaging to mimic malignant soft-tissue tumors

A solitary calvarial lytic lesion with typical histopathological findings of juvenile hyaline fibromatosis - Case report

Juvenile hyaline fibromatosis (JHF) is a rare systemic disease characterized by papulonodular skin lesions, gingivalhyperplasia, joint contractures, and osteolytic lesions on long bones and the skull. It has recently been reported that the disease is caused by mutations in the gene encoding capillary morphogenesis protein-2 (CMG-2). To date, fewer than 60 cases have been published in the literature. Partial disease expression is common, but no cases featuring a solitary calvarial lesion have been reported