Properties of mechanoreceptive fibres serving skin grafts transferred to the hands of adult baboons (Papio anubis).

In nine adult baboons, full-thickness skin grafts were reciprocally exchanged between three glabrous skin sites on one hand and glabrous skin sites on the contralateral hand or foot, and a hairy skin site on the dorsum of the ipsilateral hand. The grafts acquired some of the physical characteristics of the recipient site; glabrous skin became thinner and more pliable on the dorsum of the hand and hairy skin became thicker and displayed a more irregular surface contour when transferred to the palm. The electrophysiological properties of cutaneous mechanoreceptors serving these grafts were examined about 5 months after surgery and again after 1 year. Measurements of conduction velocity, receptive field size and shape, and responses to mechanical stimuli suggested that axons serving mechanoreceptors in glabrous grafts functioned at nearly normal levels by 5 months, while axons innervating hairy skin grafts, whether transferred to a glabrous skin site or to a hairy skin site, performed less well even after 1 year. These observations suggest that factors intrinsic to the graft are a major determinant of the quality of sensory function achieved following a skin graft procedure. These factors affect the relative proportions of rapidly and slowly adapting fibres, conduction velocities, thresholds and receptive field configurations. As a result, hairy skin is not the tissue choice for plastic surgical procedures requiring optimum sensory return.