A Cadaver Study of the Feasibility of Multidigit Allotransplantation for Reconstruction of the Metacarpal Hand.

BACKGROUND: Amputation of all fingers (metacarpal hand) can be functionally equivalent to hand amputation. Multidigit allotransplantation can benefit patients who require a full complement of fingers to return to their preinjury activities. The authors investigated the feasibility of the transfer of four fingers and thumb as a single allograft. METHODS: Four fingers and the thumb were harvested from 16 hands as an allograft based on the radial and ulnar arteries. Dorsal digital veins were dissected until confluent in the major veins. The common digital nerves were divided at the origin. The flexor and extensor tendons were transected, respectively, in zones V and VI. The fingers were disarticulated at the metacarpophalangeal joint. After harvest, ulnar and radial arteries were injected with red and blue India ink, respectively, followed by injection of lead gel in the ulnar artery to study the perfusion of the fingers. Digital radiographs and computed tomographic scans were obtained. A bilateral mock transplantation was performed. RESULTS: The ulnar artery perfused the small, ring, long, and ulnar half of the index finger, whereas the radial artery vascularized the thumb. The index finger represented a watershed area. The presence of contrast in the four fingers, decreasing toward the radial fingers, was confirmed by computed tomography. The mock transplantation procedure was performed successfully. CONCLUSIONS: Multidigit transplantation is an anatomically feasible procedure. Although the ulnar artery can supply the entire allograft, the variable anatomy of the palmar arches should be considered and the flap based on both ulnar and radial arteries.

Vascularization of the facial bones by the facial artery: implications for full face allotransplantation.

BACKGROUND: The maxillary artery is recognized as the main vascular supply of the facial bones; nonetheless, clinical evidence supports a codominant role for the facial artery. This study explores the extent of the facial skeleton within a facial allograft that can be harvested based on the facial artery. METHODS: Twenty-three cadaver heads were used in this study. In 12 heads, the facial, superficial temporal, and maxillary arteries were injected. In one head, facial artery angiography was performed. Ten facial allografts were raised. The soft tissues were dissected to show the arterial anastomotic connections. Radiographs and computed tomographic scans were obtained. RESULTS: Constant anastomosis between the facial, inferior alveolar, and infraorbital arteries at the mental and infraorbital foramina were found. The facial artery vascularized the homolateral mandibular symphysis, body, and ramus. The condylar and coronoid processes were vascularized in 67 percent of the allografts. The homolateral maxilla was contrasted in all allografts. The alveolar and palatine processes contained the contrast in 83 percent of specimens. The maxillary process of the zygomatic bone was perfused in all allografts, followed by the body, frontal (83 percent), and temporal processes (67 percent). The nasal lateral wall and septum were vascularized in 83 percent of the allografts. The medial and lateral orbital walls and the orbital floor were stained in all specimens. The zygomatic process of the temporal bone was the least perfused bone. CONCLUSION: A composite allograft containing 90 to 95 percent of the facial bones can be based on bilateral facial arteries.

Three-dimensional CT angiography: a new technique for imaging microvascular anatomy.

To date there has been no satisfactory research method for imaging microvascular anatomy in three dimensions (3D). In this article we present a new technique that allows both qualitative and quantitative examination of the microvasculature in 3D. In 10 fresh cadavers (7 females, 3 males, mean age 68 years), selected arteries supplying the abdominal wall and back were injected with a lead oxide/gelatin contrast mixture. From these regions, 30 specimens were dissected free and imaged with a 16-slice spiral computed tomographic (CT) scanner. Using three-dimensional CT (3D-CT) angiography, reconstructions of the microvasculature of each specimen were produced and examined for their qualitative content. Two calibration tools were constructed to determine (1) the accuracy of linear measurements made with CT software tools, and (2) the smallest caliber blood vessel that is reliably represented on 3D-CT reconstructions. Three-dimensional CT angiography produced versatile, high quality angiograms of the microvasculature. Correlation between measurements made with electronic calipers and CT software tools was very high (Lin's concordance coefficient, 0.99 (95% CI 0.99-0.99)). The finest caliber of vessel reliably represented on the 3D-CT reconstructions was 0.4 mm internal diameter. In summary, 3D-CT angiography is a simple, accurate, and reproducible method that imparts a much improved perception of anatomy when compared with existing research methods. Measurement tools provide accurate quantitative data to aid vessel mapping and preoperative planning. Further work will be needed to explore the full utility of 3D-CT angiography in a clinical setting.