Recovery of sensation in free flaps.

A clinical study of touch, pain, warm and cold stimuli and two-point discrimination was performed in 27 free flaps four months to four years after the microsurgical procedure. There were 5 free skin flaps (2 with nerve suture), 15 musculocutaneous, 4 muscle-covered with split skin grafts and 3 osteomusculocutaneous flaps transplanted to various sites on the body. The results show full or nearly full recovery of touch and pain sensation in all free skin flaps. The musculocutaneous and osteomusculocutaneous free flaps developed good sensation if firmly grown onto the healthy recipient skin with normal sensation. Muscle flaps covered with split skin grafts and all flaps surrounded by scar tissue had a clinical absence of sensation. This study and our earlier findings of the regeneration of nerves in free skin grafts, in skin flaps and in experimental free flaps, lead us to suggest that the healthy denervated skin of the free flap provides a strong neurotrophic stimulus to the cut cutaneous nerves in the edges of the recipient skin. Cutaneous nerves freely regenerate in the loose subcutaneous tissue of the flap. We therefore conclude that all free flaps with skin islands have a potential for developing sufficient protective touch and pain sensation and even some superficial sensitivity.