LONGITUDINAL PREAXIAL UPPER LIMB DEFICIENCY DISORDERS; GENETIC AND SURGICAL ASPECTS

Abstract

Introduction: Congenital Longitudinal radial deficiency, also called radial club hand or radial dysplasia, is an uncommon congenital anomaly characterized by various degrees of deficiency along the preaxial or radial side of the extremity. The severity of deformity ranges from mild thumb hypoplasia to complete absence of the radius. Longitudinal preaxial upper limb deficiency may occur in isolation but frequently is associated with other congenital malformations e.g. VACTERL, Holt-Oram, Thrombocytopenia with absent radius (TAR), Fanconi anemia. The management of congenital radial club hand has undergone significant changes. Numerous procedures and modifications have been developed to treat this condition. Aim: to discuss the genetic aspects, associated conditions, classification of these deformities and the management of such cases particularly the staged protocol for management of Bayne type IV and pollicization for hypoplastic thumb. Methods: 7 cases diagnosed clinically as congenital radial deficiency; 3 cases were classified as Bayne type IV congenital radial deficiency; two patients were classified as Bayne type N congenital radial deficiency while the remaining two cases were Bayne type 0. Five patients were boys, two were girls. The average age at the time of operative intervention was 12 months (range 10–15). All cases had complete physical examination, cardiac auscultation, whole skeletal radiographs, complete blood count with a peripheral blood smear and Cytogenetic studies including G-banding technique, DEB and MMC and chromosomal studies. we used a 2 stage approach for 3 cases of Bayne Type IV congenital radial deficiency, pre-centralization soft tissue distraction using light weight fibro-carbon ring external fixator (Ilizarov) followed by centralization procedure the remaining four cases of Bayne Type N and 0 deformities had hypoplastic thumbs which are further classified according to Buck-Gramcko modification of Blauth classification into: 3 cases of Grade IV (floating thumb) and one case of Grade V (total thumb aplasia) was treated by pollicization. Results: The preoperative workup showed that all these cases were isolated non syndromic unilateral radial deficiency without clinical or radiological evidence of associated anomalies or Fanconi's anemia. Improvements of wrist position parameters were noted associated with improvement in the measurements of radiographic construction lines during follow up evaluations for Bayne Type IV cases managed by the staged approach. Our results of thumb reconstruction by pollicization are uniformly good as regard to growth and mobility. Venous congestion was the most important pos-operative complication. Conclusion: by using the staged approach for type IV deformities, we can safely distract the taught soft tissues and avoid several of the difficulties often seen when centralization not proceeded by soft tissue distraction. Also, significant improvement in deformity with a more functional position of the hand can be achieved while minimizing overall complications. The aesthetic and functional results of pollicization are directly related to the transposed index digit and surrounding musculature. Pollicization of the index finger for congenital thumb hypoplasia is a well-accepted procedure with good outcome.
Key words: Longitudinal radial deficiency, radial club hand, soft-tissue distraction, centralization, thumb hypoplasia, pollicization.