1 Introduction

Amniotic band syndrome (ABS) is a congenital hand difference where fibrous annular constrictions can cause congenital disruption around extremities, resulting in possible constriction band deformity or extremity loss.¹ When ABS affects the fingertip there is frequently a bulb-like appearance due to circumferential constriction. If ABS also involves the nail, it results in a significant lateral nail fold deformity which can lead to long-term nail deformities, abnormal nail growth, and an increased risk of nail infections. A paronychia, or infection of the nail folds, can result from the loss of the normal nail architecture. These infections can be treated with oral antibiotics however abscess formation and chronic recurrences may require surgical intervention.² Thus in the setting of ABS involving the lateral nail fold, it is important to reconstruct the lateral nail fold to restore nail bed architecture, allow normal nail growth and further infection.

The traditional reconstructive techniques for amniotic bands were introduced by Upton.³ Reconstructive options include excision of the band, debulking, and local flap rearrangement with Z-plasties as well as the use of skin grafts and composite adipose-preserved skin grafts.^4,5 Due to the variability of presentation of ABS, reconstruction techniques also vary based on the patient's individual needs to restore function and create an optimal aesthetic appearance.^6,7 For example, the Mutaf procedure involves using dermofat flaps to fill the soft tissue defects and use rectangular-plasties rather than a Z-plasty.⁸ Additionally, the Wang technique involves a single-step surgery to completely resect the bands, a fascial flap reduction, and the use of multiple z-plasties.⁹ These techniques have shown improved aesthetic and functional outcomes for the extremities while also reducing the number of procedures a child may need.

The use of local flap techniques for reconstruction is well established for ABS, however a specific technique for reconstructing the affected lateral nail fold has not been described.

2 Surgical technique

A five-month old male with ABS presented with a right ring finger amniotic band (Fig. 1). Specifically, the amniotic band was constricting the distal phalanx at the lateral nail fold. There was a deep band that was constricting down to the distal phalanx bone. Notably, the patient presented with concern for infection given erythema of this fingertip, and therefore a course of Keflex (Cefalexin) antibiotics was prescribed which resolved the cellulitis. Given the significant amount of constriction down to the bone and the concern for the patient to develop chronic infections, we recommended performing the patient's reconstruction at an early age. An X-ray was obtained to confirm there was no underlying bone infection. Given the need for aggressive excision of the constriction band and flap elevation, the risk of fingertip necrosis including fingertip loss requiring amputation was discussed as a possible outcome at the time of parental consent.

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Fig. 1 Preoperative Views. The images show the constriction ring defect at the distal fingertip in the ring finger of 5-month-old male. The images show the dorsal (Top Left), volar (Top Right), and lateral views (Bottom Left and Right).

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The patient underwent general anesthesia without complication. After upper arm tourniquet placement, using 5× loupe magnification the digit was marked with a fine-tipped marking pen (Covidien Devon™ Dual Tip Surgical Tip Marker) (Fig. 2). Using Flap A on each side, the pulp on the volar side was designed to reconstruct the lateral nail folds (Fig. 3). The B line, laterally along the proximal longitudinal incisions adjacent to the lateral edges of the nail plate, is where the triangular Flap A insets, requiring it to be close to the same length. Flap C and D were marked to be equal in length (use a 4-0 silk suture thread to measure).

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Fig. 2 Preoperative Markings. The top left image shows the volar view of the flap design markings in surgical ink. The top right image shows an oblique view of the fingertip demonstrating the flap markings including the lateral nail fold flap. The bottom image shows a lateral view of the flap markings.

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Fig. 3 Luchador Pulp Flap Design. The markings, flap elevation and closure are demonstrated in volar and lateral views. There are two lateral nail fold flaps (A and B) and a central distal flap (C). The A and B flaps (blue) are elevated and are transposed from volar to dorsal adjacent to the nail plate and are inset within the B-line (green). The C flap (purple) is elevated and advanced centrally to connect with the central proximal D flap (orange). A Z-plasty (pink) breaks up and lengthens the linear closure. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

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Methylene blue was used to mark the amniotic band to ensure complete debridement of the constricted tissue (Fig. 4, Left). The amniotic band tissue between the flaps was completely debrided and excised to the level of the bone, however superficial to the periosteum (Fig. 4, Right).

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Fig. 4 Intraoperative views of constriction band excision. The figure on the left panel shows the intraoperative view of the distal flap elevated and the constriction ring is dyed with methylene blue. The image on the right panel shows after excision of the constriction ring which is discarded exposing the underlying distal phalanx periosteum. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

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Using a 67 blade (Beaver Visitec™ Miniblade #67), the proximal and distal skin flaps were incised and elevated. The incision at the B line ultimately is where Flap A will inset.

Both Flap A's are elevated volarly and transposed laterally along the proximal longitudinal incisions adjacent to the lateral edges of the nail plate (B line). Flaps C and D are elevated as well for planned advancement.

Inset is then performed using 6-0 plain gut suture (dyed with purple marking pen) by transposing the A flaps into the space made by the B line. Flap C and D are then advanced and approximated. A centrally placed Z-plasty (pink lines) was performed to help break up the linear closure given the anticipated scar contracture that would occur across a straight line. Following local tissue rearrangement, there was an immediate improvement in fingertip contour (Fig. 5). After tourniquet release, the fingertip had a normal capillary refill and tissue appearance. The patient was seen at the fourth week post-operative with improved contour of the fingertip (Fig. 6). The narration and surgical technique are included in the video attachment in Fig. 7.

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Fig. 5 Postoperative Views. The image shows the dorsal (Left), volar (Middle), and lateral (Right) views of the ring finger in the immediate postoperative period. The deformity has been improved and the flap edges are approximated.

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Fig. 6 4 Week Postoperative Views. The image shows the dorsal (Left), volar (Middle), and lateral (Right) views of the ring finger at the 4 week postoperative visit. There is improved contour of the fingertip.

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3 Discussion

The Luchador pulp flap is a novel local flap technique for the reconstruction of the pulp and lateral nail fold in patients with distal fingertip ABS. The Luchador flap is unique flap design that recreates the lateral nail fold, by taking advantage of the longitudinal excess and the pliability of the pulp tissue. Our technique demonstrates an effective local tissue flap for ABS fingertip reconstruction with an improved functional and aesthetic outcome. As opposed to traditional reconstructive procedures, this technique offers several advantages including using available excess tissue to avoid the use of skin grafts and rearranging tissue to achieve a more desired contour. Additionally, this technique entails a single-staged approach rather than a series of surgeries, thus reducing general anesthesia risk to pediatric patients.

Notably given the significant reconstruction as described for the Luchador pulp flap, it is important to discuss the potential for fingertip loss with the patient's guardian. Based on the limited blood supply, there could be inadequate perfusion leading to the loss of flaps, or infections at the operative site. These complications can be prevented with precision and careful dissection to maintain blood supply to the fingertip flaps and verifying perfusion of the fingertip during closure. Furthermore, since amniotic bands exist in utero, there are collateral blood vessels that provide additional perfusion to the distal phalanx bones, nail beds, and dorsal fingertip tissues.

Despite the results of this technique, it is well established that amniotic band syndrome presents with significant variability, and therefore modification to this technique may be necessary depending on the level of the amniotic band on the digit. Other techniques to treat constriction bands include shearing the band using a needle and using lipoinjection to fill the defect, or using traditional Z-plasty techniques.¹¹ Having the Luchador pulp flap within the armamentarium of a pediatric hand surgeon, allows for improved outcomes for the patient given the need to address all the tissues considered to reconstruct the fingertip. Long-term follow-up is necessary to assess the overall outcome of this flap and if further intervention or surgeries are needed.

Conflict of interest

No conflicts of interest to declare.

Financial support and sponsorship

No funding was obtained for this study.

Informed consent

Written informed consent was obtained from the guardian for publication of this case report and accompanying images.

Conflict of interest

No conflicts of interest to declare.

Institutional ethical clearance

Valley Children's Hospital Institutional Review Board (IRB) provided an exemption for this case report. Written informed consent was obtained from the guardian for publication of this case report and accompanying images.

CRediT authorship contribution statement

Isabel Silva: was involved in the writing and editing of the manuscript, was involved in the writing and editing of the manuscript. Thais Calderon: Dr, was involved in the edition and writing of the manuscript. Michael G. Galvez: was involved in the design of the flap and the surgical reconstruction. Additionally, he was involved in supervising and editing the manuscript.