Late toe-to-hand transfer for the reconstruction of congenital defects of the long fingers

Indications for microsurgical reconstruction of congenital hand anomalies by toe-to-hand transfers

BACKGROUND

The indications for microsurgical toe-to-hand transfers in congenital hand surgery have not been defined as clearly as for posttraumatic reconstruction of thumb and finger amputations. The purpose of this study was to develop simple guidelines for referral of children with congenital absent digits for consideration of microsurgical reconstruction with toe-to-hand transfers, based on the morphological or radiographic anatomy of the hand anomaly, not on embryological classifications.

METHODS

From a consecutive series of 204 children referred with congenital absence of the thumb and fingers, 100 toe-to-hand transfers were performed. The indications for microsurgical reconstruction of these children were analyzed retrospectively.

RESULTS

Forty-one thumbs were reconstructed in 38 children-15 children with an absent thumb distal to the metacarpal base but with four relatively normal fingers; 12 children with an absent thumb and only one or two digits remaining on the ulnar side of the hand; and 11 children with complete absence of all five digits. Twenty-nine second toes and 12 great toes were transferred to reconstruct congenital absent thumbs. Fifty-nine fingers in 52 children were reconstructed mostly with single second toe transfers-41 children with a thumb but absence of all four fingers and 11 children with absence of all five digits.

CONCLUSIONS

The morphological or radiographic anatomy of a child's hand with congenital absent digits is a more logical indication for microsurgical reconstruction than any embryological classification. The three most common indications for toe transfers for reconstruction of congenital absent thumbs are (1) absent thumb distal to the carpometacarpal joint with four relatively normal fingers, (2) absent thumb with only one or two fingers remaining on the ulnar border of the hand, and (3) complete absence of the thumb and all four fingers. The two indications for toe transfers for reconstruction of congenital absent fingers are (1) absence of all four fingers but with a normal thumb remaining and (2) complete absence of all five digits.

Precision grip function after free toe transfer in children with hypoplastic digits

Although toe-to-hand transfer has a defined role in the management of congenital hand deformities, it remains unclear how well children integrate the transferred digits into physiological grasping. We analysed fingertip forces in the precision grip of 13 patients when lifting a test object more than three years after free toe transfer for absent or hypoplastic digits. Clinically, most patients showed normal sensibility of transferred digits, but active motion and pinch strength were limited as compared to the normal hand. For the control of fingertip forces, two key features of the normal two-digit opposition grip were seen in all operated hands: adaptation of grip force to object weight and parallel coordination of lift and grip forces. These physiological grasping strategies developed independently of the patients' age at the time of operation, which ranged from one to 13 years. In four patients, we observed increased tangential load forces with the operated hand due to misalignments in the application of fingertips on the grasp surfaces. Such forces lead to increased grip force requirements on both fingers that may overload transferred digits with limited motor function. The need for optimal alignment of the grip axis during toe-transfer surgery is emphasised.

Pediatric upper extremity replantation

The evolution of microsurgical technique has led to increasing success with pediatric replantation. The broader inclusion criteria for pediatric replantation, together with the greater technical demands of repair and the less favorable mechanism of pediatric amputations (crush-avulsion), yield a slightly lower overall survival rate than in adults. The superior nerve and soft tissue regenerative capacity of children appears to produce better functional outcomes. Nonetheless, the issue of cosmesis and developing self-image in a child may have ramifications beyond a simple calculus of range of motion and strength variables--hence the imperative that microsurgical salvage be attempted in pediatric upper-extremity amputations.

[Classification and treatment of symbrachydactyly. A series of 117 cases]

In the present study, a modification has been proposed of the Blauth and Gekeler classification, aimed at a more accurate definition of appropriate surgical treatment. An analysis was made of a series of 120 cases of symbrachydactyly (117 patients); however, surgery was only performed in 86 cases (51 toe transfers in 49 patients; mean age at surgery 12 months). Type I included the separation of short and sometimes stiff fingers; type II, the 'pseudo-cleft', could be subdivided into three groups. Type IIA included those hands with more than two long and frequently hypoplastic digits, regarding which a decision had to be made between removal of rudimentary fingers or their stabilization. In type IIB, hand function was good and surgery was rarely needed. Type III (monodactylous) could also be subdivided into two categories, i.e., normal thumb in type IIIA and hypoplasia in IIIB. Finally, in type IVA, toe transfer surgery was performed on condition that wrist mobility was sufficient to compensate for the insufficient mobility of the artificial thumb on the anterior aspect of the radius. In all cases, a weak but useful pincer movement was obtained, with poor cosmetic results. In the case of toe transfers, surgery was advocated before the age of one year; and although mobility was disappointing (35 degrees active motion), good growth and excellent discrimination (5 mm on average) was observed. Symbrachydactyly is a fairly frequent congenital malformation; its diverse clinical features require a precise classification to better determine adequate treatment management.