Three Reverse Adipofascial Cross Finger Flaps Used for Coverage of Raw Areas on Two Fingers of a Patient with Blast Injury of the Hand—Case Report

We report a case of blast injury to the left hand which resulted in fractures of the fingers with exposure of bones and joints of the phalanges. We used three reverse adipofascial cross finger flaps raised at the same time from 2 fingers to reconstruct adjacent fingers of the patient. The patient recovered well post-operatively and had good range of movement of the fingers. This avoided the complications of the use of regional or distal flaps. To our knowledge, this is the first case reported in which three reverse adipofascial cross fingers flaps are raised at the same time, two of them from an injured finger, to cover three raw areas on two fingers of a patient.


Introduction
The first article that dealt with cross-finger flap was published in the year 1950 by Micheal Gurdin and John W. Pangman after the 2nd world war. They termed the procedure as "trans-digital flap". It was carved more on the lateral and volar surfaces of the donor digit [1]. Ten years later, Hoskins DH, published an article in which he described the design of the classic cross finger flap [2].
In 1978, Ivan Pakiam described the adipofascial cross finger flap [3] and further modifications took place in the design and shape of the flaps along the his-  [4]. In this case report we used 3 reverse adipofascial cross finger flaps to reconstruct 2 fingers with exposed bones and joints in a patient of war blast injury.

Case Report
A 27 years old young soldier was involved in a mine blast injury during the Yemen war which resulted in crush injury of his left hand, burns with multiple foreign bodies of the left upper limb and intraoccular foreign bodies. The patient was initially stabilized in the field hospital and transferred next day to the national military hospital for further management.
On examination, the patient was found having facial burns with foreign bo-

Operative Procedure
The patient was taken on the same day of admission to the operation theater and removal of foreign bodies from the eyes was done by the ophthalmologists. Debridement of the dirty wounds and burnt area of the upper limb and hand was done by the Plastic Surgery team. He was taken again to the operation theatre two days later for further debridement and repair lacerations of the nailbeds and arm wounds.

Discussion
Many procedures are prescribed for coverage of raw areas of the hand. Distant flaps as the groin flap can be used but have the complications of stiffness of the shoulder and elbow joints [5]. Bulkiness of the flap is one of the drawbacks and subsequent defattening is usually required in most of the cases [6].
The reversed radial forearm flap can be used as fasciocutaneous or fascial flap with preservation of the radial artery but it has the disadvantage of having a large scar over the forearm and often the need for skin grafting to close the recipient site [7]. The reverse posterior interosseous flap is another option but in addition to the scarring on the forearm, it has the disadvantages of difficulty of dissection, inconstant anatomy of the artery, possibility of injury of posterior interosseous nerve and venous congestion of the flap. The flap also needs long time of elevation and a long learning curve [8].
Raising flaps from the hand itself can avoid such complications and provides tissues of similar texture and pliability. For these reasons we preferred to use the reverse adipofascial cross finger flaps rather than distant or regional flaps in our case.
The reverse adipofascial flaps are based on dorsal cutaneous branches from the proper digital arteries of the fingers. On his cadaveric study on 180 digits, Jefferson Silva showed that there are 2 constant branches in the proximal and middle phalanges from each proper digital artery and they have consistent sites of origin at predictable distances from the proximal interphalangeal joint for the long fingers [9]. We raised our three flaps; one from the proximal phalanx and two from the middle phalanges based on this anatomical concept. In spite of having many puncture wounds of the blast injury in our flaps, they all were viable and healed well which shows the good blood supply of the flaps.
The adipofascial flaps can be raised in different ways. They can be used as homodigital flaps within the same finger as turnover flaps or as heterodigital flaps from one finger to the adjacent one.
The homodigital flap can be used to cover the dorsal aspects of the middle [10] and terminal [11] phalanges of the fingers. The flap is elevated from the dorsal aspect of a phalanx and turned over to cover the phalanx distal to it. In our case, this type of flap could not be used as there was no soft tissue on the dorsal aspect of the proximal phalanx of the index finger to be turned over to cover the middle phalanx of that finger so we had to use a heterodigital type of flaps i.e. flaps from adjacent fingers.
Heterodigital flaps can be formed of either only of the adipofascial tissue between the dermis of the overlying skin and the underlying paratenon over the extensor tendon of the phalanges or can be formed of that tissue with the overlying skin after de-epithelializing it [12]. In the last option skin graft is applied on both the turned over flap and the paratenon of the donor site as one piece.
We feel that this technique can have high possibility of implantation dermoid cyst formation if no adequate de-epithelialization of the flap is done. Also applying skin graft on both the donor and recipient digits may be unnecessary if only skin graft can be applied on the recipient digit in the procedure we used.
This will avoid disfigurement of the donor digit and maintain its normal hairy skin shape. For these reasons we preferred that our flaps to be formed only of the tissue between the dermis of the overlying skin and the underlying paratenon over the extensor tendon of the phalanges. After turning the flap 180 degrees like a page of a book and flap insetting is performed on the recipient site, the previously elevated overlying skin is turned back to cover the donor site without the need to do skin grafting of the donor digit.

Conclusion
The reverse adipofascial cross finger flap is a reliable procedure for covering raw areas of adjacent fingers. It provides soft tissue of proper thickness with good pliability and keeps the upper limb free of stiffness of distant flaps. To our knowledge, this is the first case reported in which three of these flaps were used to cover raw areas on two fingers of a patient at the same time.

Conflicts of Interest
The authors declare that they have no conflict of interest.

Compliance with Ethical Standards
All procedures performed in this study involving human participant were in accordance with the international ethical standards. Approval from the hospital