Nerve endings in palm skin grafts

Reconstruction of the transverse and dorsal-oblique amputations of the distal thumb with volar cross-finger flap using the index finger

We performed a retrospective review of 12 patients with dorsal oblique and transverse amputations of the distal thumb who were treated with a volar cross-finger flap from the index finger. The mean patient follow-up period was 28 months postoperatively (range: 19-43 months). There were no instances of flap loss, infection, or donor site complication in our series. The mean Semmes-Weinstein monofilament testing scores on the injured thumb and the donor site were 0.65 g (range: 0.16-2 g) and 0.51 g (range: 0.16-1 g), respectively. The mean 2-point discrimination testing scores on the injured thumb and the donor site were 4.5 mm (range: 3-8 mm) and 4.3 mm (range: 3-7 mm), respectively. This study suggests that the volar cross-finger flap using the index finger is a reliable technique in repairing dorsal oblique and transverse amputations of the distal thumb.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

The role of plastic surgery for soft tissue coverage of the diabetic foot and ankle

The goal of wound healing is to obtain the best closure through the least morbid means. In the surgical treatment of the diabetic foot and ankle, the reconstructive foot and ankle surgeon is tasked with the challenge of repairing a variety of tissue defects. The decision for wound closure depends on the location of the wound and host factors. In order of increasing complexity, the clinician should consider the reconstruction decision ladder algorithm. Wound evaluation coupled with the knowledge of various closure techniques and their indications will arm the surgeon with the tools for a successful closure.

p75 and TrkA neurotrophin receptors in human skin after spinal cord and peripheral nerve injury, with special reference to sensory corpuscles

Human skin, including nerves and sensory corpuscles, displays immunoreactivity (IR) for low- (p75) and high-affinity (TrkA-like) receptors for nerve growth factor (NGF), the best characterized member of the family of neurotrophins. This study was designed to analyze the changes induced by spinal cord and peripheral nerve injuries in the expression of neurotrophin receptors in digital skin, with special reference to nerves and sensory corpuscles. Skin biopsy samples were obtained from 1) the hand and toes of normal subjects, 2) below the level of the lesion of patients with spinal cord injury affecting dorsal and lateral funiculi, 3) the cutaneous territory of entrapped peripheral nerves (median and ulnar nerves), and 4) the cutaneous territory of sectioned and grafted nerves (median nerve). The pieces were formalin-fixed and paraffin-embedded, cut in serial sections, and processed for immunohistochemistry using antibodies against human p75 and TrkA proteins. The percentage of sensory corpuscles displaying IR for p75 and TrkA-like, as well as the intensity of IR developed within them, was assessed using quantitative image analysis. Spinal cord severance causes a decrease in p75 IR in Meissner and Pacinian corpuscles, whereas TrkA-like IR did not vary. In other nonnervous tissues (i.e., epidermis, sweat glands), both p75 and TrkA-like IR was diminished or even absent. Similar but more severe changes were encountered in the skin from the territory of entrapped nerves. Finally, in subjects with sectioned-grafted nerves, p75 IR was found close to controls in nerves, reduced in Meissner corpuscles, and absent in the inner core of the Pacinian ones; TrkA-like IR was in the perineurium, a small percentage of Meissner corpuscles (about 7%), and the outer core and capsule of the Pacinan corpuscles. In the nonnervous tissues, p75 IR was practically absent, whereas TrkA-like IR did not change. No changes in the expression of neurotrophin receptors were observed in Merkel cells of the different groups. Present results show the following: 1) expression of nerve p75 IR in human cutaneous sensory corpuscles is sensitive to central deafferentation, to blockade or difficulty in axonal transport, and to disruption of axonal continuity independently of possible restoration of axonal integrity due to grafts; 2) expression of TrkA-like IR in nerves and sensory corpuscles is sensitive only to nerve transection; 3) the corpuscular Schwann-related cells are the only cells involved in the above modifications, the perineurial cells remaining unchanged; 4) the expression of p75 and TrkA-like IR by Merkel cells is independent of normal innervation; 5) an adequate innervation of the skin seems to be necessary for the expression of p75 but not TrkA-like in nonneuronal cells, especially in the epidermis. A role for NGF in the maintenance of epidermis integrity is discussed.

Reinnervation of split skin grafts in humans: comparison of two different methods of operation

Studies on the reinnervation of split skin grafts have produced contradictory results. As the difference in sensitivity may be caused by the method of grafting, sensory reinnervation was studied in split skin grafted by two different methods. Thirty-nine patients given split skin grafts after the excision of malignant melanoma took part in the study. In 17 patients, split skin was grafted on to the intact muscle fascia. In another 22 patients the skin was grafted directly on to the muscle after the fascia had been removed. In all patients, sensitivity (to touch, heat/cold, and pain) was tested on the grafts and the skin from the opposite side. Sensory functions on grafted skin were generally reduced. Patients with split skin grafted on to the intact muscle fascia had better reinnervation than the ones in whom the fascia had been removed. However, individual patients from both groups showed surprisingly good reinnervation of transplanted skin. The reasons for this finding are not clear, but it is quite possible that the characteristics of the grafted skin have some influence on the reinnervation.

Human glabrous skin autografts partially reinnervated without sensory corpuscles. An immunohistochemical study

The reinnervation of human glabrous skin autografts was investigated in biopsy specimens obtained four weeks to 15 months after transplantation. The grafted skin was taken from the volar aspect of the wrist and transplanted to the fingers. Immunohistochemical methods were used to detect the presence of nerve fibres and sensory corpuscles, using monoclonal antibodies against neurofilament proteins and S-100 protein. In normal skin, immunoreactivity of neurofilament proteins was localised in the axons of nerves and sensory corpuscles, while S-100 protein immunoreactivity was found in Schwann cells, lamelar cells and inner core cells of sensory corpuscles. In the transplanted skin, there was no positive immunoreactivity in the youngest grafts (four weeks), but in eight week old grafts immunoreactivity to both proteins, identified as axons or Schwann cells, respectively, were seen in the deep nerve plexus, and these reached subepithelial dermis in the 15 month old grafts. In no case, however, were immunoreactive structures found that resembled reinnervated or regenerated sensory nerve corpuscles. Clinical assessment of sensibility was consistent with morphological findings. These results suggest that reinnervation of human skin autografts is far from normal, and that sensory corpuscles are not able to regenerate in grafted human glabrous skin, at least during the times studied.