Congenital Syndactyly of the Fingers : A Report of Two Cases

Introduction

Syndactyly is the second commonest congenital hand anomaly and occurs in about 1:2500 live births, more commonly in males, and is most often seen in the third web space¹. The condition has a strong familial tendency and is usually bilateral in presentation. It can be either primary or secondary, the former being due to a failure of differentiation or separation. Secondary syndactyly is a result of antecedent events and is produced by refusion abnormality². Syndactyly may present as the sole abnormality or may be associated with other syndromes like Poland's, Cleft hand or Apert's¹. The anomaly can also be classified as either complete or incomplete, depending on the extent of fusion of adjacent digits. Complete syndactyly is the type where the fingers are joined from the web to the tip. Incomplete syndactyly denotes a type where the fusion of the web spaces occurs only at a point between the web and the tip. Simple syndactyly defines a subtype in which only the skin is involved while complex syndactyly involves bone, the neurovascular bundle and nail structure.³

Case report

A 13 year old girl presented to us with complaints of deformity of both hands since birth. Clinical and radiological evaluation suggested a complete complex syndactyly between middle and ring finger of both hands [Figures 1(A), 1(B)]. Radiographs revealed a bony fusion between the terminal phalanges of the middle and ring fingers [Fingers 2(A), 2(B)]. A complete clinical evaluation showed no association with any syndrome or any underlying systemic disease.

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Fig. 1(A) and 1(B)

Image showing complete and complex syndactyly between the 3^rd and 4^th digits of both hands

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Fig. 2(A) and 2(B)

Image showing complete and complex syndactyly between the 3^rd and 4^th digits of both hands

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She underwent a complete bony release with secondary skin grafting as a primary procedure. Six weeks later she was reviewed and was noted to have a scar contracture [Figure 3] with restriction of finger movements. Z-platy was performed and scar contracture release was done as a secondary procedure. Four months after the second surgery she was reviewed and she was noted to have acceptable range of motion of all the digits and she was able to do all daily activities comfortably with ‘fair results’ as per the criteria of Cortez et al.⁴ No other complications were noted.

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Fig. 3

After the primary syndactyly release of both hands. Note the flexion contracture of right middle finger at distal interphalangeal joint with malrotation in ringht middle and left ring finger.

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The second case was of a two year old male child, who presented with complaints of deformity of the left hand since birth. Clinical and radiological evaluation led us to a diagnosis of a simple type of syndactyly between the index and ring finger of left hand [Figure 4(A), 4(B)]. Clinical assessment and detailed evaluation showed no association with any systemic illness or association with any syndrome.

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Fig. 4(A)

Simple incomplete syndactyly of left hand between index and ring fingers.

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Fig. 4(B)

AP, Lateral and oblique views of the left hand showing no bony fusion between index and ring fingers confirming a simple type of syndactyly.

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He underwent a percutaneous release of the syndactyly with a zig-zag incision. He was followed up at regular intervals and during the final follow up after 4 months of surgery, he was noted to have full range of motion of the digits with an acceptable hand function [Figure 5]. He was noted to have ‘fair results’ as per the criteria of Cortez et al.⁴ No complications were noted.

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Fig. 5

After surgical release of syndactyly. Note the left hand is nearly similar to the digits of the right hand after release.

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Discussion

Most published studies regarding the surgical reconstruction of syndactyly include heterogeneous populations of patients with simple, complex, and complicated syndactyly. Previous authors have noted that complex syndactyly has poorer outcomes with worse function, increased finger deformity, and a higher rate of revision surgery.^{5, 6, 7, 8} The purpose of this investigation was to evaluate a homogeneous group of complete, complex syndactyly patients, using both objective and subjective outcome measures, in an effort to better understand the specific challenges of reconstruction.

The aim of treatment in syndactyly is to separate the fused digits, provide cutaneous cover and create a normal web space. In the past, there have been numerous techniques described for syndactyly correction. The methods have differed in respect of separation of the digits and reconstruction of the web space. It is accepted that longterm stability of the newly created web space is best achieved when the web space is reconstructed using a flap.⁹

Traditional surgical approaches to syndactyly repair have used flaps from the dorsum of the involved fingers and dorsal and palmar interdigitating flaps. Surgical correction of syndactyly needs to be simple and have a minimal rate of secondary correction.^{10, 11, 12}

Current techniques use zigzag incisions along the full length of the fingers and interdigital flaps to wrap the web space. Zigzag incisions show a lower rate of digital scar contracture than straight line closure. Cutaneous flaps, which can be dorsal, palmar, or both, do bring a skin of good quality, colour, and growth into the web compared with skin grafts.^{10, 11, 12} Separated digits, however, have a greater surface area than syndactylized digits and generally skin grafts are used to cover the raw areas, with some morbidity.¹¹

The purpose of our study was to evaluate and study the different treatment options and types of syndactyly and their surgical outcomes^{13, 14}.

Cortez et al; reported a series of 35 cases of syndactyly and concluded that varying degrees of surgical outcomes was noted in the simple and complex forms.⁴

Lumenta et al; in his series of 26 affected web spaces who underwent surgery with palmar and dorsal skin flaps with zig-zag incisions for separation of digits. They reported a reduced incidence of web creep during their follow ups after surgery.¹⁵

In our case we presented two different types of syndactyly managed by two different techniques and the surgical outcome of both the patients at the end of four months was excellent.