Low-velocity civilian gunshot wounds of the spine.

This article describes a retrospective study on patients admitted to a level I trauma center between 1989 and 1993 with low-velocity gunshot wounds to the spine. Medical records and imaging studies were reviewed to determine patient demographics, neurologic deficit, prophylactic antibiotic administration, and rate of infection, spine stability, and principle associated injuries. A total of 37 patients with low-velocity gunshot wounds to the spine were identified and comprised 34% of all spinal injury patients.

Regression of human colon cancer xenografts in SCID mice following oral administration of water-insoluble camptothecins.

Gastrointestinal cancers pose major public health problems worldwide, in part because little progress has been made in the treatment of colorectal cancers. The present study explored the potential use of natural product topoisomerase I inhibitors, 10-hydroxycamptothecin (HCPT) and camptothecin (CPT), in the treatment of human colon cancers. HCPT and CPT are indole alkaloids originally isolated from th.

Segmental avascularity of the humeral diaphysis after reamed intramedullary nailing.

Although the clinical experience with reamed intramedullary nailing has been successful for the treatment of femur and tibia fractures, similar success has not been duplicated when this technique has been applied in the humerus. Although the cortical vascular response to nailing of the humerus is presently assumed to be similar to that of the femur, the response of the humerus to reaming has not been documented in vivo. The following case depicts avascularity of the humeral diaphyseal cortex as a complication of reamed intramedullary nailing and illustrates the sensitivity of the humerus to this treatment.

The torsional strength of bones with residual screw holes from plates with unicortical and bicortical purchase.

OBJECTIVE: To evaluate the effect of unicortical and bicortical screw holes on residual bone strength by comparing the in vitro torsional strength of cadaveric sheep tibiae with screw holes from plates with unicortical and bicortical purchase relative to each other and to intact bone. DESIGN: The paired tibiae were grouped randomly and torsion tested to failure as follows: Group I -- unicortical screw holes versus intact bone; Group II -- bicortical screw holes versus intact bone; and Group III -- bicortical versus unicortical screw holes. BACKGROUND: Recently the point contact fixator, or PC-Fix (using screws with unicortical purchase), was designed to minimize bone devascularization beneath the plate compared to the conventional dynamic compression plate, or DCP (bicortical purchase), and possibly reduce refracture rates after plate removal.

Recurrent rotational deformity of the femur after static locking of intramedullary nails: case reports.

Rotational deformity following intramedullary nailing may cause symptoms and require surgical correction by osteotomy. Reamed, locked intramedullary nailing may be performed, but concern about cortical blood supply and potential pulmonary dysfunction from reaming have led many surgeons to limit this and use smaller diameter nails. Slotted nails are commonly used but are less stiff in torsion than the newer unslotted nails, particularly at the lower diameters.

Effect of cefazolin and vancomycin on osteoblasts in vitro.

The effect of cefazolin and vancomycin on osteoblast-like cells was studied. Cells from the MG-63 human osteosarcoma cell line were grown in antibiotic free media and exposed to concentrations of cefazolin and vancomycin at order of magnitude intervals between 0 and 10,000 microg/ml. For cefazolin, a second interval was performed between 100 and 1000 microg/ml to define toxic levels more accurately.

Ureteral injury after anterior lumbar interbody fusion. A case report.

Study Design: This case report presents a patient with ureter injury after anterior spinal fusion and its management.

Objectives: To present possible causes, symptoms, diagnostic approach, and management of this rare complication.

Summary Of Background Data: The reported complications of anterior surgical approaches to the lumber spine have been predominantly vascular or neurologic.

Long-term treatment with lipoteichoic acid from Streptococcus faecalis affects differentiation and expression and cellular distribution of beta 1 integrins in human urothelial cells.

Gram-positive bacteria are recognized pathogens in urinary tract infections. Cellular mechanisms triggered by lipoteichoic acids (LTs), cell well components of gram-positive bacteria, have not been completely defined. We have postulated that infection-induced altered function of progenitors of urothelial cells residing in the basal layer is likely to have long lasting effects on the architecture and function of the urothelium.

A cluster of murine typhus cases in Western Australia.

Measures to control rodents have resulted in a decreased incidence of murine typhus, but it is also likely that it is being underdiagnosed because many medical practitioners do not include it in their differential diagnosis of pyrexia of unknown origin. Four recent cases are described, and historical aspects of this disease in Australia are presented.

Segmental variations of bone mineral density in the cervical spine.

Study Design: This study assessed the variability of segmental bone mineral density in the lower cervical spine (C4 through C7). A mean segmental bone mineral density value at each level was determined for all specimens, and a mean coefficient of variation among the 17 specimens was calculated.

Objectives: To quantify the degree of intersegmental bone mineral density variations within cadaveric lower cervical spine segments.

Closed Tibial-Shaft Fractures: Which Ones Benefit From Surgical Treatment?

Closed tibial-shaft fractures can usually be managed effectively with cast or brace immobilization if acceptable alignment is maintained and cyclic loading (weight-bearing) is initiated early. However, certain tibial fractures are at greater risk for nonunion or malunion and merit consideration for early operative stabilization. Among the tibial fracture characteristics that warrant fixation are instability, metaphyseal-diaphyseal location, significant limb edema, and the need for repeated realignment procedures.

Autogenous cancellous bone graft incorporation in a gap defect in the canine femur.

While gap defect models provide greater graft stability and are more representative of many clinical situations than segmental defect models, the healing in these models has not been well documented. To study the histologic course of cancellous bone graft healing in a long bone gap defect, 12 adult mongrel dogs were killed in groups of two at 1, 2, 3, 4, 6, and 12 weeks. Graft incorporation in these dogs was studied using macro- and microradiography, histologic sections, and computer-assisted digital surface analysis; results are described.

Late reconstruction of patellar ligament ruptures using Ilizarov external fixation.

Chronic patellar ligament ruptures, on which failed reconstruction attempts have been made, cause structural changes in the quadriceps mechanisms with marked fixed proximal migration of the patella. Before reconstruction, the position of the patella must be normalized. When using Ilizarov principles and an Ilizarov external fixator to treat these ruptures, full weightbearing and range of motion can be maintained throughout the pre- and postreconstruction period.

Effect of directional symmetry on the torsion testing of paired long bones.

Paired long bones (canine humeri) demonstrated no significant biomechanical difference between left and right limbs torsioned tested symmetrically (a) both internal: (b) both external or asymmetrically, (c) right internal/left external.

An in-vitro biomechanical comparison of the Orosco and AO locking plates for anterior cervical spine fixation.

The Orosco anterior cervical spine plate (H-plate) and the Morscher AO cervical locking plate (CSLP) were studied to determine their comparative in vitro mechanical properties in flexion. Human cadaver cervical spines were tested nondestructively in flexion as intact, destabilized, and stabilized specimens with both implants. Stabilized specimens were also subjected to a large angular displacement in an attempt to induce implant failure.

A mechanical comparison of the dynamic compression plate, limited contact-dynamic compression plate, and point contact fixator.

Cortical bone porosis associated with the dynamic compression plate (DCP) prompted the development of the limited-contact dynamic compression plate (LC-DCP) and the point-contact fixator (PC-Fix) to increase bone vascularity. However, the comparative fixation characteristics of the three designs are unknown. Transverse fractures were physiologically created in paired cadaveric sheep tibiae, which were plated before torsion testing and four-point bending to failure.

Bone toxicity of locally applied aminoglycosides.

The effect of tobramycin on osteoblasts was studied. Osteoblast-like cells from the MG-63 human osteosarcoma cell line were grown in antibiotic-free media and exposed to concentrations of tobramycin: first at order of magnitude intervals between 0 and 10,000 micrograms/ml, and then at closer intervals between 100 and 1,000 micrograms/ml to more accurately define toxic levels. Cell number and 3H-thymidine incorporation at 0, 24 and 72 h were determined.

Effects of retained diaphyseal plates on forearm bone density and grip strength.

Numerous complications have been attributed to elective plate removal following successful treatment of both bone diaphyseal forearm fractures, yet the effects of retained implants are not known. Fourteen patients were reviewed for residual forearm grip strength (FGS) and bone mineral density (BMD) following uneventful union. Patients were analyzed in two groups based upon time from fixation: group I, > 2 years but < or = 5 years, and group II, > 5 years.

Effect of dose and field strength on enhancement with paramagnetic contrast media.

Purpose: To compare contrast enhancement per unit of dose of contrast medium in MR imaging at 0.5 and 1.5 T.

Efficacy of radiographic evaluation of the cervical spine in emergency situations.

Evaluation of trauma to the cervical spine usually includes predominantly normal x-ray studies that prevent expeditious workup and treatment and increase cost. In a retrospective review of the cases of 1,686 consecutive trauma patients who had routine radiographs for possible injury to the cervical spine, injuries were detected in 32 (1.9%).

In vitro pharmacokinetics of antibiotic release from locally implantable materials.

Local deposition of antibiotics has became increasingly popular in the management of open fractures or osteomyelitis, and several substances have been employed as the vehicle for delivery. Although the elution characteristics of some substances have been documented, a comparative study of the characteristics of the commonly used substances could establish the clinical indications for particular vehicles. Cylindrical pellets of uniform size (6 x 4 mm) were prepared from bone graft (BG), demineralized bone matrix (DBM), plaster of Paris (POP), or polymethylmethacrylate (PMMA), with 25 mg of tobramycin/g of substance in each pellet.

The effects of antibiotic-impregnated autogeneic cancellous bone graft on bone healing.

Autogeneic cancellous bone graft has been recommended as a vehicle for local antibiotic delivery. Its effect on graft incorporation, however, is unknown. The healing of defects grafted with tobramycin-impregnated cancellous bone were compared with those grafted with cancellous bone alone.

Ulnar neuropathy after median sternotomy.

Ulnar neuropathy is a known complication of median sternotomy surgery, and its precise cause is not clear. The authors hypothesize that a "double-crush" phenomenon caused by intraoperative compression of the brachial plexus occurs in a patient with preexisting, previously undiagnosed slowing of ulnar nerve conduction. Eighty-four arms in 42 patients scheduled for cardiac surgery were studied.

A defect-in-continuity in the canine femur: and in-vivo experimental model for the study of bone graft incorporation.

The in-vivo study of bone graft incorporation has traditionally used a segmental diaphyseal bone defect. This model reliably produces a nonunion, but is complicated by graft instability and altered limb loading stresses. The authors discuss the advantages of a defect-in-continuity canine femur model which produces a more consistent union with fewer mechanical complications despite the absence of fixation.