Restoration Of Function In The Child With A Congenital Thumb Deficiency By Staged Pollicization Of The Radial Finger
By James M. Hunter, M.D. Thomas Williams, M.D.
Traumatic deformities and birth deficiencies of the upper extremity may be managed in either the Amputee Clinic or the Hand Clinic at the Pennsylvania State Hospital for Crippled Children at Elizabethtown. As the clinic teams vary only in the substitution of the prosthetist and orthotist, a closely knit, cooperative program has developed, permitting frequent re-evaluation of children with complicated congenital deficiencies in the upper extremity.
Regardless of approach, the goal of reconstructive surgery, functional bracing, or prosthetic design is to provide some type of purposeful grasp. The terminal longitudinal deficiencies-i.e., complete and incomplete paraxial radial and ulnar hemimelias, partial adactylia, and partial aphalangia-comprise a significant percentage of the upper-extremity congenital anomalies seen in our Amputee and Hand Clinics. Cases such as these present a myriad of possibilities for the restoration of digital prehension with sensation. Clinic team members have been in full agreement that, when possible, every avenue of surgical reconstruction should be explored before resorting to a final prosthetic fitting.
Variability of the Problem
The child with a congenital thumb deficiency presents a complex and challenging problem in reconstructive hand surgery. Rarely is one child's problem the same as another, and the surgical approach must often follow a "play it by ear" pattern.
Occasionally, when a "floating" thumb is of reasonable size, the proximal shift by Z-plasty and bone graft, described by Barsky, or the staged metacarpal lengthening, described by Carroll, may be utilized with an acceptable cosmetic and functional result. More often, however, the floating thumb presents on a tiny skin pedicle, rendering it of no reconstructive value; or the thumb is completely absent, requiring the surgeon to consider other approaches or do nothing. Our experience with isolated procedures such as Z-plasty of the radial web or rotation osteotomy of the thumb metacarpal indicates that the results fall short of good thumb function, offering little or no better than a tricky side-to-side substitution pattern and volar dorsal digit pinch (Fig. 10 ).
Considerations in Pollicization
The single-stage operation for pollicization of the index finger on a neurovascular pedicle in adults as described by Bunnell, Littler, and others suggested a dramatic solution to the problem. A review of our cases with congenital thumb deficiency, however, revealed the presence of several rather consistent problems requiring careful consideration if the end results of our surgery were not to be adversely affected:
Skin and soft tissue deficiencies on the radial side of the hand (Fig. 16 ) were common. Syndactyly of the radial digit may require dactylization and skin grafting in preparation for pollicization, adding further to the deficiency of available soft tissue (Fig. 15 ).
Contractures of the metacarpophalangeal and proximal interphalangeal joints were noted frequently (Fig. 7 , Fig. 10 , Fig. 20 ). This condition would limit the length of either or both opposing surfaces, and if the metacarpal were shortened to give up extra skin for a single-stage procedure, the resulting function would be seriously compromised. In some cases it appeared that almost the entire metacarpal length might be necessary to produce good pinch and grasp.
Unpredictable neurovascular anomalies could be expected in congenital thumb-deficient hands, and with the additional hazard of a tight skin closure around the bas of the digit, the single-stage procedure could well end in vascular catastrophe. The possibility that at some time in the future the pollicized digit might be compromised ("for the need of a shoe, the horse was lost"), and the child's situation made worse, led to the formation of a program that would make available, at the time of pollicization, a generous amount of well-vascularized pedicle skin.
In an effort to be conservative in approach and yet bold in aspiration, we have elected to use a multi-staged approach to pollicization that routinely incorporates the use of abdominal pedicle skin by the tube method during the shift of the radial ray on a neurovascular pedicle.
The operative procedure for staged pollicization will be outlined, and five children with progressive degrees of congenital thumb deficiency will be presented to illustrate the problem, the approach, and the results.
Outline of Procedure
Stage I. Preparation of a closed full-thickness abdominal pedicle skin tube. Generally the tube is placed obliquely in the upper abdominal quadrant opposite to the hand being reconstructed. Prior to surgery the tube dimensions are mapped out on the skin in methylene blue. The length of the tube is determined by measuring the distance from a point between the bases of the first two metacarpals, on the dorsum of the hand, through the web of the newly projected cleft to the midline of the palm. The width of the tube is approximately one-half the overall length. The skin edges of the tube are closed without tension, and the abdominal skin is undermined and closed primarily.
By ten days to two weeks, the abdominal tube may be exposed for soap showers, and aside from a dry pad placed between the skin surfaces after washing, the area is left exposed. Transfer of the tube to the dorsum of the hand may be accomplished at any convenient time after three weeks.
Stage II. Transfer of the pedicle tube to the hand. The bed for the tube transfer is prepared in a bloodless field by excising a small triangle of skin over the dorsum of the proximal two-thirds of the two radial metacarpals. The dorsal veins are preserved, the tourniquet is released, the midline foot of the tube is elevated from the abdomen, the abdominal skin defect is closed primarily, and the pedicle is sutured in place on the hand. The hand is dressed in the position of function, and a plaster valpeau is applied and windowed for tube observation and redressing. The hand may be detached from the abdomen at three weeks or any convenient time thereafter.
Stage III . Detachment of the hand from the abdomen. The hand is detached from the abdomen by severing the abdominal tube transversely. The free end is covered with Vaseline gauze. The abdominal skin is then closed primarily. The hand, wrist, and tube are dressed on a functional splint to guard against the possibility of vascular embarrassment. Stage IV is usually carried out within the following five to seven days.
Stage IV. Shift of the radial metacarpal, on a neurovascular pedicle, to the thumb position. The incision begins dorsally at the apex of the skin tube (Fig. 23 ), and it is then carried through the web to approximately midpalm.
The transverse metacarpal ligament (Fig. 5 ) is divided, and the neurovascular bundles to both digits are identified and protected. Several restraining structures must be divided to free the radial metacarpal: palmar fascia, tendon anomalies if present, intrinsic muscle fascia, and the juncture tendon between the extensor tendons.
To complete the soft tissue release, the tube should be opened (Fig. 5 )and the skin edges gently freed. Care must be exercised, as the vital nutrition to the skin pedicle comes from the dorsal skin.
The neurovascular bundles should again be identified and the digital nerves separated deep in the intrametacarpal space. The digital artery to the remaining stable digit may be ligated now or after metacarpal osteotomy. This vessel may be preserved in some situations.
The metacarpal osteotomy is accomplished in routine fashion through a lateral metacarpal shaft incision. A transverse osteotomy, or parallel osteotomies if bone is being resected, has facilitated the positioning of the metacarpal in abduction, opposition, and rotation (Fig. 11 ). The new position is held by two or three K-wires (Fig. 6 ). After fixation of the metacarpal, the skin pedicle is sutured in position and excess skin is discarded. During the last phase of Stage IV, the tourniquet should be intermittently released and the vascular status of the tube and pollicized digit determined.
Dressing should be compressive and supportive early. Plaster fixation should be maintained for four to six weeks or until union of the metacarpal is noted and the K-wires are removed.
Postoperatively the hand and the pollicized thumb are gradually mobilized under a strictly supervised, daily program in the physical therapy and occupational therapy departments. The children seem anxious to learn to use their new thumbs, and prolonged training periods have not been necessary.
Patient #1--R.A. Partial Adactylia. Probable Absence Of Rays III And IV.
Patient #2 --W.H. Right Paraxial Hemimelia (Radial) and Hypoplasia of Thumb
Staged pollicization was started when the child was 9 years of age. Preparatory surgery consisted of soft tissue releases at the wrist, osteotomy of the forearm, and excision of the hypoplastic thumb. Following pollicization, the extensor carpi radialis was transferred to improve extension of the digit.
Patient #3--T.Y. Partial Adactylias. Absent Thumb And Syndactyly Of Rays Ii And Iii (Right). Radial Hemimelia And Fused Elbow (Left).
All five stages of pollicization were completed within five months. A three-plane metacarpal osteotomy with 3/8-inch shortening was performed as a separate fifth stage due to concern over vascular status from previous dactylization.
Patient #4--G.C. Right Paraxial Hemimelia (Radial). Absent Thumb and Index Rays.
Despite bracing since first year of life, this deformity required several plaster corrections prior to pollicization. Adequate bracing of the forearm and the wrist will be required until growth is completed.
Patient #5--R.M. Partial Adactylia (Bilateral). Absent Thumbs, Five-Finger Hands. Lower Extremity, Bilateral Hemimelia (Tibial).
This patient is completely ambulatory, fitted as a bilateral above-knee amputee with quadrilateral, plastic suction sockets.
Five children with terminal longitudinal congenital skeletal limb deficiencies, all lacking thumb function, have been discussed to illustrate our approach to the restoration of function in the hand by staged pollicization. The surgery in these patients was carried out by a senior orthopedic resident under the close operating table supervision of the Clinic Chief. No serious complications have developed, and results have exceeded early predictions with respect to improved function.
The authors would like to acknowledge the contributions of the members of the Amputee and Hand Clinic teams. Their dedication and devotion has played a major role in the achievement of the final results described in this presentation: Ronald Masitis, R.P.T., Mrs. Minerva G. Thome, R.P.T., Miss Adaline J. Plank, A.B., O.T.R., Alfons R. Glaubitz, C.P.O., James E. Sweigart, CO., Gene Snyder, CO., and Francis S. Gilmore, X-rays and photography.
Barsky, A.J., Congenital Anomalies of the Hand and Their Surgical Treatment, Springfield, Ill.: Thomas, 1958.
Bunnell, S., Surgery of the Hand, 4th Edition, revised by Joseph H. Boyes, M.D. Philadelphia, Pa: Lippincott, 1964.
Carroll, R.E., Personal communication
Littler, J.W., "The Neurovascular Pedicle Method of Digital Transposition for Reconstruction of the Thumb," Plast. Reconstr. Surg., 12:303, 1953.
By James M. Hunter, M.D. and Thomas Williams, M.D. are associated with Child Amputee Clinic State Hospital for Crippled Children Elizabethtown, Pennsylvania