The arterial supply to the fingertip arises from the proper digital arteries which divide into three branches (not two) at the level of the distal interphalangeal (DIP) (not proximal interphalangeal [PIP]) joint. Then at the level of the lunula, the distal transverse palmar arch (DTPA) is formed, and central arteries branch off this to supply the fingertip and pulp. The digital nerves are located superficial to the digital arteries more proximally in the digit, so frequently are divided where arterial injury has occurred. The ulnar digital artery is dominant in the radial three digits (thumb, index, and long fingers), while the radial digital artery is dominant in the little and ring fingers. This is due to the embryological development of the limb from the median artery. The dorsal (not volar) venous supply is dominant in the digit and veins around the lateral nail wall and distal pulp also form an arch over the distal phalanx. A second arch is formed more proximally over the middle phalanx. The presence of these arches is relevant to distal tip replantation surgery.1,2
2. Nam YS, Jun YJ, Kim IB, Cho SH, Han HH. Anatomical study of the fingertip artery in Tamai zone I: clinical significance in fingertip replantation. J Reconstr Microsurg 2017;33(1): 45–48 There are many important considerations in fingertip reconstruction, but in general, the primary goal is to have a painless fingertip which is sensate and has durable soft-tissue coverage. This serves to optimize functional outcomes and minimize morbidity. Preservation of length and range of motion is also important, although achieving these at the expense of the other parameters described would be futile. Pain is a major issue to patients especially in the fingertip where the nerve supply is dense and the areas are exposed to mild trauma on a regular basis. Furthermore, poor vascularity and poor soft-tissue cover can accentuate the discomfort for patients following fingertip injury. Minimizing time off work and from leisure activities is also important. Individuals who are self-employed will often be particularly motivated to return to work early. In some cultures, the aesthetics of the fingertip are especially important, though in most cases function still assumes the highest aim.1
Allowing fingertip injuries to heal by secondary intention is often the best choice for a number of reasons, providing the defect is relatively small. First, it can avoid the need for surgery and additional donor-site morbidity to the same or adjacent fingers where flaps would otherwise be harvested. Second, it avoids the need for a skin graft donor site and for dermal substitutes, which can be expensive. Third, the outcomes are usually good with durable sensate tips achieved. Digit length is also well preserved and although in some cases there needs to be shortening of the bone, this is certainly not required in all cases and even when it is necessary, only minimal amounts generally need removal and this is easily undertaken under local anesthetic. Initially, dressings are left for 1 week in most cases, but beyond this patients are generally encouraged to change the dressings on a daily basis and wash the digit with soap and water. Low adherence dressings can be used to protect the healing area. Healing time in most cases is around 4 weeks. Return to work is expected to be as quick, if not quicker, than where grafts or flaps are used for fingertip repair. The caveat of allowing healing by secondary intent is that in larger defects, scar contraction and deformity may occur with problems such as a hook nail or reduced range of motion.1
Defects of the fingertip may rarely be reconstructed using skin grafts, and it is far more common to allow things to heal by secondary intent. The theoretical advantage of using skin grafts is that larger defects can be reconstructed with accelerated healing, reduced scar contraction, and low donor-site morbidity. However, most authorities would generally avoid grafts for fingertip reconstruction as healing by secondary intent or flap reconstruction each is associated with better outcomes, particularly where sensibility is concerned. Where grafts are used, full-thickness grafts are preferable for the fingertip, as they have a number of advantages. First, the cover provided is more durable and thicker than with split grafts. Second, the color match tends to be better, and third, the donor site may be closed directly. Split grafts are probably more likely to take than full-thickness grafts and are simple to harvest. The healing time is likely to be similar with split- versus full-thickness grafts. Split grafts will have less primary contraction but have more secondary contraction than full-thickness grafts. In general, grafts are to be avoided in fingertip injuries.1,2
The Venkataswami flap1 is an oblique triangular V-Y advancement flap used for reconstructing volar oblique injuries of the fingertip. It is based on a single neurovascular pedicle and is generally designed to extend proximally from the PIP joint to the defect, but some surgeons prefer to have a longer flap length beginning proximal to the PIP joint, while others prefer to extend the proximal incision in a linear fashion only to facilitate flap reach (Fig. 78.1). V-Y closure Mobilize flap to reach defect Flap to include isolated bundle Defect Proper digital artery and nerve A B C D Fig. 78.1 Venkataswami flap. (Germann G, Sherman R, Levin LS. Reconstructive Surgery of the Hand and Upper Extremity. Thieme, 2017.) Another similar flap is the Segmuller flap, which is a smaller version and is therefore useful for smaller defects.2 The Kutler V-Y advancement flap3 is a bilateral technique that was described for transverse amputations but may be more suited to lateral oblique injuries of the digits. Two triangular flaps are designed and centrally placed to cover the defect (Fig. 78.2). The problem with these flaps is that they do not have much movement and can lead to scarring of the fingertip, hence the reason why the Venkataswami and the Segmuller have become popular. Both the Atasoy4 and the Furlow5 flaps are types of volar advancement flaps that are indicated for reconstructing dorsal oblique and some transverse injuries. They are not based on the neurovascular pedicle; so, again advancement is far more limited. The Souquet flap is a rectangular flap not a V-Y flap, rotated so that the free edge advances to cover a defect in the fingertip. It is based on the neurovascular bundle but does not advance especially well. It has been modified by Lloyd and Sammut to maintain sensation and yet improve reach.6
6. Lloyd N, Sammut D. A modification of the Souquet advancement flap in fingertip reconstruction. J Hand Surg Eur Vol 2013;38(4):395–398 The Moberg flap is used for thumb tip defects because of the unique dual dorsal and volar blood supply which the thumb possesses. Although a Moberg advancement flap is potentially feasible for reconstruction of the index fingertip, it is not recommended, as it requires division of the dorsal branches of the digital vessels, and this can lead to subsequent dorsal skin necrosis. While it is possible to preserve many of these branches using a tissue- spreading technique, the Moberg flap is still best reserved for thumb reconstruction. Following reconstruction of a thumb tip defect using the Moberg flap, there is a small risk of subsequent IP joint stiffness, partial flap failure, and cold intolerance to the tip, but these risks are not specific to the Moberg flap. Ensuring careful and adequate flap mobilization can limit this and it is key to advance the flap to the thumb defect rather than the other way around, as the latter would cause the IP joint flexion.1
The Moberg flap is a volar advancement flap described for reconstruction of thumb tip defects. It has a robust vascularity because it is elevated on both neurovascular pedicles simultaneously. It is useful for closing volar soft-tissue defects of the thumb 1 to 1.5 cm in diameter. There are some modifications that can be incorporated Fig. 78.2 Kutler flap dissection. to increase flap reach. These include the use of a V-Y advancement technique or by using a transverse incision at the base to create an island flap, which needs to be allowed to heal by secondary intent or skin grafted. Dellon’s modification involves extension of the flap base into the first web space and this can increase advancement to around 3 cm. The surgical time is most likely to be slightly increased (not decreased) in modifications of the flap, as a result of the extended dissection involved.1–3
The main drawback to using the cross-finger flap to reconstruct an index fingertip defect is the postoperative lack of tactile gnosis, which is reported to occur in all patients.1 Normal tactile gnosis is very important to maintain in the index finger, given its key role in pinch grip, key grip, and precision activity. Protective sensation is generally well maintained with this flap, although it requires cortical relearning. There is plenty of donor soft tissue available from the cross- finger flap in most cases, as this is harvested from the dorsum of the middle finger. It is a technically straightforward procedure that can be accomplished under local anesthetic in a few minutes. The risk of long-term postoperative stiffness is low because splinting can be achieved in the safe position (or close to it) with the IP joints in full extension. In patients of darker skin tone, transfer of dorsal skin to the volar surface results in poor aesthetic outcomes with obvious visible scarring due to the differences in pigmentation between the volar and dorsal skin surfaces.
The Quaba flap is not useful for fingertip reconstruction because it does not have sufficient reach to move much beyond the PIP joint. Flow can be antegrade through perforators from the dorsal metacarpal artery (DMA) or retrograde from the volar system or the dorsal digital arteries. Perforators are primarily distal to the junctura tendinea in the distal third of the dorsum of the hand. All of the other flaps are useful for thumb or fingertip reconstruction (see Fig. 78.12).1,2
The pedicled island flap described by Littler1 is used to reconstruct large defects of the thumb tip and is most commonly used for ulnar (not radial) pulp defects. It can be harvested from either the ring or middle fingers and involves sacrifice of one of the digital arteries and nerves to the donor digit. It involves significant dissection into the palm in order to obtain sufficient reach and to tunnel the pedicle. The donor defect requires a skin graft.
finger? The thenar flap involves a two-stage process. In the first stage, an area of skin and subcutaneous fat is raised from the thenar eminence and inset into a volar defect of the index (or middle) fingertip. In the second stage, at 10 to 14 days, the flap is divided and inset is completed. The donor site is closed, grafted, or left to heal by secondary intention. The main problem with this flap is that the index finger is flexed at the PIP joint between the first and second stages. This can result in stiffness and loss of motion to the PIP joint secondary to collateral ligament and volar plate tightening that may not fully recover. For this reason, it should be avoided in older patients and those with comorbidities such as arthritis and Dupuytren’s disease. The flap has a low failure rate and availability of suitable (glabrous) tissue is good for fingertip reconstruction. The need for a second stage and the potential for a donor-site graft represent limitations, but these are less of a problem (Fig. 78.3).1–4
The ring and little fingers have an important functional role in the power grip of the hand. For this reason, it is important to maintain joint mobility (flexion, in particular, combines with wrist extension) while minimizing pain. Sensibility and aesthetics are generally less important features.1
Non-microsurgical replantation of the amputated fingertip is known as composite grafting and is not usually recommended in adults. The main indication is in children younger than 6 years. Some authorities think that composite grafts act only as biologic dressings that allow granulation and healing from underneath, while others believe they are able to successfully act as true grafts. Attempts have been made to improve graft take by cooling (not warming) the grafts postoperatively. In spite of recommendations to reserve the technique for use in children, there have been successful reports of their use in adults. Graft survival has been improved by excision of bone, defatting, tie over-suturing, and finger splinting.1,2 Composite grafting is best suited to clean sharp lacerations rather than crush injuries.
In this scenario, no critical structures are exposed, and the defect is no more than 1 cm2 in size; so, healing by secondary intention should be fairly quick, easy, and give good cover, color, contour, and sensation to the finger over time. The use of skin grafts would be undesirable, as each would give a worse outcome than healing by secondary intent and also involve a donor site. The Littler neurovascular island flap is indicated as a heterodigital flap, for example, to reconstruct the thumb. Using the Venkataswami neurovascular island flap would be unnecessary for this case, as the defect is small and there is no exposed bone.1
The Venkataswami flap is well suited to reconstruct larger volar oblique defects of the fingertip such as this case. A unilateral triangular island flap is designed as a V-Y based on a single neurovascular pedicle. The apex of the flap is located proximal to the PIP joint and can be extended even more proximally if required to further increase flap reach.1 The Atasoy flap is a volar V-Y flap useful for dorsal oblique fingertip injuries and some transverse injuries. This flap is designed to match the width of the nail bed with the volar wound edge as the base of the flap. This flap can advance only up to 1 cm and involves skin-only incisions with tissue spreading action to release the subcutaneous tissues. The Littler neurovascular pedicled flap maybe used to reconstruct thumb tip defects on the ulnar side. The donor is normally from the ulnar pulp of the ring finger. This flap does require extended dissection into the palm and tunneling over to the thumb to be successful. For this reason, it is not frequently used in most units.2 The cross-finger flap uses dorsal skin to reconstruct volar skin on the adjacent digit. It could be used in this scenario but can lead to stiffness, as the two adjacent digits must be immobilized together postoperatively. The Kutler V-Y flap is described for transverse fingertip amputations and some lateral oblique injuries. It is designed as bilateral lateral V-Y flaps advanced distally and centrally; however, there is limited reach available with these flaps.3
The flexor pollicis longus (FPL) tendon is exposed but intact, and the distal phalanx is exposed to the tip. The dorsal The options for this patient include a cross-finger flap from the index finger or a Foucher flap. Of these, the Foucher flap would be preferable due to the robust soft-tissue coverage and the potential for sensory relearning. A Moberg flap would not be large enough. A Littler flap would leave a large defect on the donor finger and is perhaps better suited to smaller defects. A cross-finger flap would fail to provide adequate sensation, which is a key requirement for the thumb pulp. The common principle in thumb reconstruction is maintenance of length; so, with bone length preserved in these scenarios, the aim should be to find soft-tissue cover.1–3