Second toe wrap-around flap

The microsurgical second toe wrap-around technique is an ideal treatment option for reconstruction of the distal half of the finger with circumferential loss of skin and nail associated with an uninjured proximal interphalangeal joint and an intact insertion of the flexor digitorum superficialis tendon. Follow-up of 13 flaps in 10 patients from 1986 to 1989 demonstrates rapid and adequate functional recovery as well as satisfactory aesthetic appearance in all patients.     

Small toe muscles for defect coverage

Defects on the sole of the foot are always a major problem. Frequently, these patients suffer from other diseases, such as diabetes mellitus, chronic vascular diseases, or skeletal deformities. Usually, these are full-thickness defects and the bone is exposed. Beside other possibilities, the short muscles of the fifth toe provide a viable muscle flap for coverage of small defects, especially on the lateral side of the foot.     

Combined second and third toe transfer

Historically, restoration of hand function following multiple digital amputation has been unsatisfactory. The evolution of digital reconstruction with toe transfer has enabled surgeons to reestablish prehension in these severely injured hands. A 4-year experience with 26 consecutive combined second and third toe transfers to replace missing adjacent fingers was reviewed in order to delineate the indications and technical considerations and to emphasize prevention of donor-site complications. Combined second and third toe transfer is reserved for adjacent finger amputations proximal to the digital web space with remaining fingers no longer than the small finger. Radial amputations are replaced with contralateral combined toe units, while ipsilateral toes are more ideal for ulnar amputations. Limited dorsal and plantar skin flaps extending only to the midpoint of the first and third digital web spaces allow for direct donor-site closure and uncomplicated healing. Maintenance of the plantar metatarsal arch by avoiding metatarsal shaft osteotomies or bone grafting-shortened metatarsals eliminates potential gait disturbances. When properly applied in selected patients, this single-stage microsurgical procedure can restore prehensile function, improve the appearance of the hand with multiple digital amputations, and preserve near-normal donor-foot function.     

Convergent evolution of lizard toe fringes

Lizard toe fringes are composed of laterally projecting elongated scales and have arisen independently at least 26 times in seven families of lizards. Four different fringe types are identified: triangular, projectional, conical and rectangular. To determine if variation in fringe morphology can be attributed to environmental differences, each independent evolution of a fringe type is identified; correlation of substrate types with evolutionary independent fringe morphologies are then studied. Variation in fringe morphology shows a strong association with substrate type: triangular, projectional and conical fringes with windblown sand; and rectangular fringes with water. Some aspects of fringe morphology may result from differences in functional requirements, and others may have no adaptive significance. This example of convergent evolution points out difficulties inherent to comparative studies of adaptation and underscores the value of broad comparative surveys which provide an alternative to ad hoc adaptive explanations of similarity.     

Congenital curved nail of the fourth toe

Five cases of congenital curved nail of the fourth toe are reported. Patients included four males and one female; four cases were bilateral, and one was unilateral. There were no other significant associated anomalies of the extremities, and only the fourth toes were affected. The features of the deformity are a curved nail and hypoplasia of the soft tissue and bone of the distal phalanx of the fourth toe. This anomaly may be transmitted autosomally and is unique in that it may be of mesodermic origin.     

Genomic DNA analysis from mouse toe lysates

The protocol described in this report provides a simple, accurate and efficient assay for detection of transgenes and mutations in large colonies of rodents, using crude lysates prepared from the digit cut from the animals for identification purposes. This can be done as early as 6 days of age, minimizing trauma to the mice and allowing assays to be completed long before weaning. Editor's note: The US Food and Drug Administration (FDA) had amended its regulations on good laboratory practice (GLP) for nonclinical laboratory studies regarding humane procedures for animal identification and expreimentation (Vol. 54 # 75). While discouraging use of toe clipping for animal identification, the FDA charged each facility's Institutional Animal Care and Use Committee (IACUC) with the responsibility for evaluation and final approval. C.A.P.     

Simultaneous multiple toe transfers in hand reconstruction

Our experience with simultaneous transfer of two or more toe units to the same hand where multiple digits were missing is presented. Forty-six toes from 38 feet were transferred to reconstruct 19 hands in 19 patients. The transfers consisted of 7 combined second and third toe units and 32 single toes. Three patients had a primary and 16 patients had a secondary reconstruction. There was one complete and one partial failure. The two-point discrimination ranged from 6 mm to protective sensation. Total active movement averaged 57 degrees in the thumb and 127, 93, 71, and 68 degrees, respectively, in the fingers reconstructed at middle phalanx, proximal phalanx, metacarpophalangeal joint, and metacarpal head. Pulp-to-pulp pinch averaged 2.4 kg in patients who had thumbs reconstructed and averaged 3.0 kg in patients who had normal thumbs. There was no cold intolerance, and no significantly disabled foot occurred except one with scissoring deformity. Simultaneous multiple toe transfer in hand reconstruction is feasible without increased complications both in primary and secondary wound conditions. It is time-effective and cost-effective.     

Elastic modulus of tree frog adhesive toe pads

Previous work using an atomic force microscope in nanoindenter mode indicated that the outer, 10- to 15-??m thick, keratinised layer of tree frog toe pads has a modulus of elasticity equivalent to silicone rubber (5?C15?MPa) (Scholz et al. 2009), but gave no information on the physical properties of deeper structures. In this study, micro-indentation is used to measure the stiffness of whole toe pads of the tree frog, Litoria caerulea. We show here that tree frog toe pads are amongst the softest of biological structures (effective elastic modulus 4?C25?kPa), and that they exhibit a gradient of stiffness, being stiffest on the outside. This stiffness gradient results from the presence of a dense network of capillaries lying beneath the pad epidermis, which probably has a shock absorbing function. Additionally, we compare the physical properties (elastic modulus, work of adhesion, pull-off force) of the toe pads of immature and adult frogs.     

Delayed toe transplantation: experimental study and clinical application

Delay of the operation in toe transplantation was performed with circulatory crisis, and 100 percent survival of the transplants was achieved. In 10 cases of toe transplantation in which circulatory crisis occurred, the operation was delayed. The vascular pedicle was divided, and the toe was transferred 17 to 21 hours after the donor toe was dissected. To investigate the mechanism of delayed toe transplantation, experiments in rabbits were carried out. In 36 rabbits, the hind limbs were severed except for the vascular pedicle. The endothelin content and nitric oxide content of the tissues in the hind limb and the arterial wall were tested in postoperative intervals of 4, 8, 16, 24, and 48 hours, respectively. The results showed that in 10 cases of delayed toe transplantation, all toes survived. As for the results of the experiment, there was significant increase of endothelin content and decrease of nitric oxide content in the local tissues and the arterial wall 4 to 8 hours after the operation. In postoperative 16 to 24 hours, endothelin content returned to normal level, and nitric oxide content increased remarkably. It is concluded that delayed pedicle division and toe transfer is an effective method in toe transplantation with vascular variations and circulatory crisis. The mechanism is related to the endothelin and nitric oxide content in the local tissue and the arterial wall. The indications for delayed toe transfer are also discussed.