Ann. Medit. Burns Club - vol. 6 - n. 3 - September 1993
THE REGENERATION OF SKIN SENSITIVITY AFTER EXTENSIVE BURNS Stella M., Magliacani G., Calcagni M., Panzica G.C., Ramieri G. Divisione Chirurgia Plastica e Centro Grandi Ustionati, Ospedale C.T.O., Turin, Italy SUMMARY. This work provides histological confirmation of superficial sensitive structures following scarring, and highlights the presence, in grafts, of fibres and superficial receptors. Fifteen patients were selected for the study, in which standard aesthesiological tests were used, integrated with the Weber and the Dellon test. The anti-protein gene product 9.5 was used to evidence the presence of nerve structures in normal skin, dermo-epidermic grafts and scars. The relative distribution of the structures regenerated in various anatomical regions is almost equal to normal, quantitatively speaking, even if the absolute number may be less. Introduction Extensive burns affect the nervous
system at all levels. Lesions of the central nervous system, although they may jeopardize
the patient's life, will not be considered here. However, in the peripheral nervous
system, the lesion may occur in various forms, in all cases accompanied by degeneration
and regeneration. Materials and methods For this study 15 patients were
selected with dermo-epidermic grafts of at least 6 months' standing, together with 8
patients with spontaneous burn scarring sequelae. These were studied aesthesiologically by
standard tests integrated with the Weber test and the Dellon test. Fourteen patients
subjected to reconstructive plastic surgery for other pathologies involving the sacrifice
of healthy skin acted as controls for the study. Results Normal skin. A large number of
nerve structures are evidenced by means of the anti-PGP 9.5 antibody in normal skin. It is
possibile to observe a rich subpapillary plexus from which fibres branch out, cross the
dermo-epidermic junction and penetrate the epidermis, where their route becomes variable. Immunoreactive structures were also observed around vases, glands and hair bulbs. Dermo-epidermic grafts. Examination of grafts of at least 6 months' standing showed a well-established subcutaneous plexus with fasciae running among the dermic papillae in a direction parallel to the dermoepidermic junction. From this plexus varicose fibres run straight into the epidermis. Two types of receptors were observed: 1) free dermic endings, and The latter, less numerous than the dermic
receptors, were situated among the keratinocytes as far as the most superficial strata. In
rare cases, immunoreactive structures were observed around the vessels. Capsulate
structures were not observed at all. Three types of receptors were observed: 1) free intraepithelial endings, The free endings were located among the keratinocytes as far as the most superficial layers. The Merkel complexes consisted of groups of round and ovoid cells in contact with specialized expansions of a single nerve fibre. The complexes were mostly situated in the basal stratum of the epidermis. No Meissner corpuscles were observed in any case. Immunoreactive structures were also observed around the vessels. Discussion Classical histological techniques (in
particular argentic impregnation) made it possible to carry out the first studies on the
nervous system, but they are unspecific and repetitive and unable to resolve certain
doubts on the morphology and classification of fibres and receptors. In recent years
technical advances in chromatography and electrophoresis have permitted the isolation and
study of increasingly purer protein fractions, including the protein gene products. Used
as an immunohistochernical marker, the PGP 9.5 has proved to be particularly useful for
the study of the peripheral nervous system, both in the normal state (Wang, 1990) and when
regenerating (Stella, 1990). Conclusions Classical aesthesiology recognized the
recovery of sensitivity in the scar, often characterized by dysaesthesia and/or
paraesthesia. The present work provides histological confirmation of the presence of
superficial sensitive structures. RESUME. Cette étude offre une confirmation histologique de l'existence de structures sensitives superficielles à la suite de la cicatrisation, et met en lumière la présence, dans les greffes, de fibres et de recepteurs superficiels. Quinze patients ont partécipé à cette expérience, dans laquelle les auteurs ont utilisé les tests normaux esthésiologiques plus le test de Weber et celui de Dellon. L'anti-produit génétique protéique 9,5 a été utilisé pour manifester la présence de structures nerveuses dans la peau normale, les greffes dermoépidermiques et les cicatrices. La distribution relative des structures régénérées dans les diverses régions anatomiques est à peu près égale à l'état normal, du point de vue quantitatif, même si le numéro absolu peut être inférieur. BIBLIOGRAPHY
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