Upper extremity composite tissue allotransplantation imaging

Abstract

Objective: Upper extremity (UE) transplantation is the most commonly performed composite tissue allotransplantation worldwide. However, there is a lack of imaging standards for pre- and posttransplant evaluation. This study highlights the protocols and findings of UE allotransplantation toward standardization and implementation for clinical trials.

Methods: Multimodality imaging protocols for a unilateral hand transplant candidate and a bilateral mid-forearm level UE transplant recipient include radiography, computed tomography (CT), magnetic resonance (MR) imaging, catheter angiography, and vascular ultrasonography. Pre- and posttransplant findings, including dynamic CT and MR performed for assessment of motor activity of transplanted hands, are assessed, and image quality of vessels and bones on CT and MR evaluated.

Results: Preoperative imaging demonstrates extensive skeletal deformity and variation in vascular anatomy and vessel patency. Posttransplant images confirm bony union in anatomical alignment and patency of vascular anastomoses. Mild differences in rate of vascular enhancement and extent of vascular networks are noted between the 2 transplanted limbs. Dynamic CT and MR demonstrate a 15° to 30° range of motion at metacarpophalangeal joints and 90° to 110° at proximal interphalangeal joints of both transplanted hands at 8 months posttransplant. Image quality was slightly better for CT than for MR in the first subject, while MR was slightly better in the second subject.

Conclusion: Advanced vascular and musculoskeletal imaging play an important role in surgical planning and can provide novel posttransplantation data to monitor the success of the procedure. Implementation of more standardized protocols should enable a more comprehensive assessment to evaluate the efficacy in clinical trials.

Figures

Figure 1

Right hand radiographs. Surgical planning posteroanterior and lateral (a, b) radiographs of the right hand of subject 1 demonstrate flexion deformity of the wrist and amputation of fifth finger at the proximal interphalangeal (PIP) joint (arrowhead). Flexion deformities of the second and third metacarpophalangeal joints and second through fourth PIP joints are present (arrows). The thumb is held in adduction (block arrow).

Figure 2

Vascular ultrasonography. Preoperative vascular ultrasonography at the proximal right upper arm of subject 1 demonstrates high arterial bifurcation of brachial into radial and ulnar arteries. Also seen are 2 radial veins (*), one ulnar vein (#), and the basilic vein.

Figure 3

Catheter angiography. Preoperative catheter angiography in subject 2 demonstrates normal vascular anatomy with patent brachial, radial, and ulnar arteries on both left (a, b) and right (c, d) sides.

Figure 4

Bilateral elbow radiographs. Frontal radiographs of the bilateral forearm of subject 2 at 1 (a, c) and 9 months (b, d) following transplantation demonstrates maturing callus formation and osseous bridging of the radius and ulna at the transplant site. There is interval improvement in soft tissue swelling. No hardware complication is present. Alignment at the elbow and wrist is anatomic.

Figure 5

Bilateral upper extremity CT. 3D volume rendered images of both upper extremities obtained 8 months after transplantation demonstrates osseous fusion of the donor and recipient radii and ulnae in subject 2. The fingers are held in flexion at the proximal interphalangeal and distal interphalangeal joints.