Avascular necrosis of common bones seen in the ED

Rapid prototyping of scaphoid and lunate bones

In this study, a novel rapid prototyping technology was used to fabricate scaphoid and lunate bone prostheses, two carpal bones that are prone to avascular necrosis. Carpal prostheses were fabricated with an Envisiontec Perfactory SXGA stereolithography system using Envisiontec eShell 200 photocurable polymer. Fabrication was guided using 3-D models, which were generated using Mimics software (Materialise NV, Leuven, Belgium) from patient computer tomography data. The prostheses were fabricated in a layer-by-layer manner; approximately 50-microm thick layers were observed in the prostheses. Hardness and Young's modulus values of polymerized eShell 200 material were 93.8 +/- 7.25 MPa and 3050 +/- 90 MPa, respectively. The minimum compressive force required for fracture was 1360 N for the scaphoid prosthesis and 1248 N for the lunate prosthesis. Polymerized Envisiontec eShell material exhibited high human neonatal epidermal keratinocyte cell viability rate in an MTT assay. The results of this study indicate that small bone prostheses fabricated by stereolithography using eShell 200 polymer may have suitable geometry, mechanical properties, and cytocompatibility properties for in vivo use.

Destructive, Granulating Lesion in the Temporal Bone After Elevated Plasma Homocysteine

OBJECTIVE

This is a presentation of a seemingly new otolaryngologic disease.

SETTING

This study was conducted at a tertiary referral center.

CASE REPORT

A 38-year-old healthy man developed left-sided sudden deafness with vertigo and temporary left facial palsy. A granulating and destructive lesion in the left temporal bone was discovered; repeated histologic examination only showed simple granulation tissue. After 6 months, a part of the bony cochlea was extruded. With approximately 8 months' delay and after the patient had had postoperative lung embolism, plasma homocysteine was found to be significantly elevated, a condition known as an independent risk factor for thromboembolic lesions. In the acquired form, it is most often caused by nutritional deficiency of vitamin B cofactors. Accordingly, the patient was treated with folic acid, which rapidly normalized plasma homocysteine. Subsequently, the granulation tissue in the temporal bone gradually disappeared, clinically and radiologically, and the lesion healed, obviously without cochlea function.

CONCLUSIONS

Thromboembolic lesion in the left temporal bone, probably in the thin end artery a. labyrintina, i.e., an avascular osteonecrosis. During the latest years, an association between avascular osteonecrosis (most often in the hip) and conditions with increased risk of thrombosis such as hyperhomocystinemia has been established but, to the best of our knowledge, it is never with a lesion in the temporal bone.