Thoracic pedicle subtraction osteotomy in a pediatric patient: a case report.

STUDY DESIGN: Case report. OBJECTIVE: To describe a case of thoracic pedicle subtraction osteotomy (PSO) for congenital kyphosis in a child. BACKGROUND INFORMATION: Although congenital kyphosis is rare, it is a challenging cause of pediatric myelopathy and frank paralysis. Even less common is the use of PSO for the surgical management of focal congenital kyphosis. We present the case of a child with congenital kyphosis that was managed with a pedicle subtraction osteotomy. METHODS: A detailed history and physical examination were performed with careful review of the patient's medical records and x-ray studies. A PSO at T11 was performed along with T9 through L1 instrumented posterolateral fusion. CASE DESCRIPTION: A 10-year-old girl was evaluated for walking difficulty and a lump on her back. Physical examination revealed a sharp gibbus kyphosis in the lower thoracic spine with tenderness and bilateral back muscle spasms. The patient displayed difficulty with balance lacking a smooth, regular gait rhythm. Clonus and radiculopathy were not present. Plain x-ray of the thoracolumbar spine revealed hyperkyphosis and failure of anterior wall segmentation between T10 and T11 vertebral bodies. Cobb's angle measured 65 degrees. Due to her symptoms and degree of correction required, we elected to perform a PSO at T11 along with T9 to L1 posterolateral instrumentation fusion. No intraoperative complications occurred. There was a significant improvement in her posture and gait. DISCUSSION: A thoracic PSO for congenital kyphosis was safely performed with an excellent outcome. To our knowledge, this is the first PSO procedure performed in Uganda.

T8 spinal cord transection in a 6-year-old child.

STUDY DESIGN: Case report. OBJECTIVE: To describe a case of spinal cord transection in a 6-year-old child. BACKGROUND INFORMATION: Non-missile injury of the spinal cord is not common and its incidence varies according to the country. In addition, to our knowledge, there are no published reports of spinal cord injury (SCI) from a penetrating nail. Here, we report the case of a child who developed complete SCI because of cord transection by a nail. METHODS: A detailed history and physical examination were performed along with careful review of the patient's medical records. In addition, a review of the literature was conducted to assess the incidence and treatment of similar injuries. CASE DESCRIPTION: A 6-year-old boy was admitted to the hospital after falling from a tree and landing on a nail. His physical examination revealed an emaciated child with multiple decubitus ulcers, lying on his side in bed. Visible was a well-healed posterior puncture wound at the T8 vertebral level. On neurological examination, the patient had 0/5 muscle strength in his lower extremities, symmetrical areflexia, and hypoesthesia below the T8 level. Plain x-ray of the thoracolumbar spine was normal. Magnetic resonance imaging revealed a transected spinal cord at the T8 vertebra, consistent with his nail puncture wound. DISCUSSION: This report describes an unusual case of a complete SCI in a pediatric patient caused by penetrating trauma from a nail. To our knowledge, this is the first case to report on complete SCI due to trauma from a nail.

The difference in spine specimen dual-energy X-ray absorptiometry bone mineral density between in situ and in vitro scans.

BACKGROUND CONTEXT: Human cadaveric specimens are commonly used to evaluate bone-implant interface strength in osteoporotic spine fixation. Dual-energy X-ray absorptiometry (DXA) scans are usually carried out on explanted spine specimens to measure bone mineral density (BMD) before in vitro biomechanical studies are carried out. PURPOSE: The purposes of this study were to verify and quantify the difference in DXA BMD between unexplanted (in situ) and explanted (in vitro) scans and to develop and validate a correction factor (CF) between in vitro and in situ DXA BMD. STUDY DESIGN: This is a retrospective analysis of past DXA scans of explanted specimens and a repeated measure scan rescan study of in situ and in vitro spine specimens. METHODS: Dual-energy X-ray absorptiometry scans were previously carried out on 106 male and 83 female lumbar specimens. Using multiple regressions, the correlation functions between Z score, BMD, and age were determined for male and female groups. The CF was developed based on difference in BMD between mean in vitro and population data. Next, in situ DXA scans were carried out on the lumbar spine of four full human cadavers, and subsequently, in vitro scans were repeated after explantation. The CF was applied to these in vitro scan data and the resulting corrected BMD compared with in situ scan values. RESULTS: The specimens had significantly lower Z score than population mean. The mean Z score was -0.7+/-1.4 (p<.001) for male and -0.3+/-1.3 (p=.03) for female specimens. The difference between in situ and in vitro scans was quantified to be 0.06 g/cm(2) for male specimens and to be a function of age (6.80 Age(-0.5)-3.76 Age(-0.365)) for female specimens. In vitro BMD was 96+/-11% of in situ BMD and was significantly different (p=.04). Corrected BMD after application of CF was 97+/-11% of in situ BMD and was not significantly different (p=.13). CONCLUSIONS: In vitro BMD scan on explanted specimens measured lower DXA values than in situ BMD scans on full cadavers. A CF when used resulted in more accurate measure of the in situ BMD.

Hydroxyapatite-coated tapered cementless femoral components in total hip arthroplasty.

Tapered cementless femoral fixation provides a reliable option for routine primary total hip arthroplasty (THA). The use of hydroxyapatite (HA)-coated stems is increasing as a result of mounting evidence that HA may improve the reliability of bone osseointegration and improve overall THA outcomes. These trends are based on a growing body of literature that supports both the theoretical and clinical rationale of this approach. There is solid clinical evidence that the combination of tapered geometry with an HA coating increases the likelihood of reliable femoral fixation. A comprehensive review of this literature evaluating the clinical use of cementless femoral components that use an HA coating is presented, and reveals that HA-coated stems have significantly improved proximal femoral fixation with less stress shielding and superior osseous remodeling. Although these advantages have not been shown to significantly increase long-term durability, there is sufficient data to support the routine use of HA-coated, tapered cementless femoral stems in THA.

Posterolateral spinal cord decompression in patients with metastasis: an endoscopic assisted approach.

Spinal tumors that are radioresistant or cause bony compression of the spinal cord often require surgical decompression to protect or restore neurological function. Metastatic lesions and primary tumors such as multiple myeloma usually arise in the vertebral body, which can collapse and become unstable, and can compress the anterior columns of the cord. Laminectomy is often ineffective in these patients, and direct anterior decompression through thoracotomy is the widely-accepted solution to the neurological problem. The anterior surgical approach is particularly challenging in the upper thoracic spine. Patients with limited pulmonary reserve due to pneumonectomy or pulmonary metastasis might not tolerate the loss of lung capacity necessitated by either thoracotomy or thoracoscopy. Because posterior instrumentation is usually needed to provide stability following corpectomy and spinal cord decompression, posterolateral approaches to spinal cord decompression have gained favor in recent years. Posterolateral decompression offers advantages over the combined anterior and posterior approach, reducing operative time, morbidity, and hospital stay. Drawbacks to traditional posterolateral decompressions include poor visualization of the tumor immediately anterior to the spinal cord and the need to manipulate the spinal cord to completely remove a tumor adherent to the dura. Endoscopically assisted posterolateral decompression allows decompression of the anterior surface of the spinal cord, the point of pressure in most circumstances. Endoscopic video assistance facilitates vertebrectomy, cord decompression, and anterior reconstruction, all performed through the same posterior incision. Endoscopic assisted spinal cord decompression dramatically reduces morbidity, ICU requirements, and inpatient hospitalization and has proven useful for a variety of metastatic tumors at every level of the spinal column.

Hip and knee arthroplasty in the geriatric population.

Osteoarthritis is the leading cause of hip and knee pathology in the geriatric population. Hip and knee arthroplasty are the definitive interventions to alleviate pain and restore physical functioning. Complications related to these procedures do occur: the most com-mon of these are infection, thromboembolism, dislocations, and periprosthetic fractures. New improvements related to minimally invasive and computer-assisted navigation surgery techniques are promising and already have shown excellent outcomes in patients exposed to joint arthroplasty.