J. SCHMAMAN and L. CARR From the Department of Prosthetic Dentistry,
University of the Witwatersrand,
Johannesburg, South Africa
A technique is described for the prosthetic replacement of two fingers using acrylic resin. Retention was obtained using finger rings. The stages of the technique are outlined. Advantages and disadvantages are briefly stated. Journal of Hand Surgery (British Volume)
17B : 673-674
A five-year-old boy who had lost the second and third fingers of his right hand requested prosthetic replacement. He was right-handed. The aim was to replace the missing fingers with a strong, firmly attached prosthesis which would restore the appearance of the hand and permit removal and replacement by the patient. Heatcured acrylic resin was used in preference to silicone rubber because of its greater durability. Anchorage was provided by two finger rings which were placed over the two remaining fingers and were attached to the prosthesis. Some degree of synchronous movement would occur during flexion and extension of the remaining fingers.
a layer of quick-setting plaster of Paris was poured over the surface of the impression to provide support. After the material had set, the hand was gently manoeuvered out of the impression. Finally, a stone cast was poured (Fig. 2).
TECHNIQUE An irreversible hydrocolloid impression was taken in the following manner: petroleum jelly separator was applied thinly onto the patient’s hand and a sheet of paper towelling was placed on the work surface. A layer of thinly mixed irreversible hydrocolloid was then poured onto the towelling. The palmar surface of the patient’s hand was guided into the impression material avoiding perforation, and the fingers were maintained in a relaxed position (Fig. 1). Irreversible hydrocolloid was poured over the dorsal surface of the hand. He was instructed to keep his hand motionless during the setting time. Next,
Stone cast of the hand.
Two well-fitting silver finger rings were obtained to be worn on each of the remaining two fingers. A length of 18 gauge stainless-steel wire was soldered onto each ring (Fig. 3). Wax fingers, joined at their proximal end, were carved to harmonize with the fingers of the cast. The trial prosthesis was transferred to the patient’s hand, evaluated and adjusted on aesthetic criteria. The rings were
The hand in the initial layer of the impression. 613
THE JOURNAL OF HAND SURGERY VOL. 17B No. 6 DECEMBER 1992
Finger rings with wire extensions.
positioned on the remaining fingers, which had been lubricated, and the wires were bent parallel to the long axis of the wax fingers. Grooves were carved into the palmar surface of the wax to receive the wires, which were sealed into position. The final textured wax-up, together with the attached rings, was processed into acrylic resin using standard denture prosthetic techniques, with the addition of specific tinting and colouring to match the existing fingers.
DISCUSSION Advantages The rings provided adequate retention for the finished prosthesis. The patient was able to remove and replace the prosthesis which had a degree of synchronous movement with the natural fingers. The prosthesis gave a relatively normal appearance (Figs 4 and 5) which improved the patient’s self-image considerably.
with his prosthesis
Alternative techniques Disadvantages It is possible that damaged retention rings could in turn injure the patient’s fingers. The parents were instructed to ensure that the prosthesis would not be worn at night. This should be regarded as an interim prosthesis, and periodic replacement will be required as growth takes place.
A wrist strap is unsightly and is difficult to manage. Skin adhesives do not provide sufficient retention to hold such a prosthesis. Accepted: 26 November 1991 Dr J. Schmaman, Department of Prosthetic Johannesburg, P 0 Wits, 2050, South Africa. 0 1992 The British Society
of the Hand