Reconstruction of fingertip amputations with full-thickness perionychial grafts from the retained part and local flaps.

The treatment of fingertip amputations distal to the distal interphalangeal joint when the amputated part is saved is difficult and controversial. Both reattachment of the amputated portion as a composite graft and microvascular anastomosis are prone to failure in this distal location. The authors have evolved a reconstructive plan that uses the nail matrix, perionychium, and hyponychium of the amputated fingertip as a full-thickness graft when the amputation is between the midportion of the nail bed andjust proximal to the eponychial fold. Various flaps are used to lengthen and augment the finger pulp, and skeletal pinning is carried out as necessary. The charts of 15 patients who underwent this procedure over a 38 month period were evaluated retrospectively. Seven returned to the office for examination at least 1 year after the fingertip reconstruction described above; four others were interviewed by telephone. Nail deformity, fingertip sensation, and joint range of motion were evaluated, and the reconstructed fingertips were photographed in standardized views. In six of the seven patients seen in the office, aesthetic and functional results were judged as good by both patient and physician; one of the six had minimal nail curvature. The seventh patient had no nail growth, although finger length was retained and there was no functional disability. The four patients interviewed by phone reported normal fingertip use with no dysesthesias or cold intolerance; all had nail growth, although three patients described slight nail curvature that required care in trimming. The authors favor salvage of all perionychial parts when a distal fingertip amputation occurs. Reconstruction of the fingertip with grafting of the hyponychium, perionychium, and nail matrix from the amputated part combined with local flaps can provide a very satisfactory functional and aesthetic result.     

A new strategy of fingertip reattachment: sequential use of microsurgical technique and pocketing of composite graft

Many methods have been used to reattach amputated fingertips. Of these methods, microsurgery has been accepted as the procedure of choice because the defining characteristic of a microsurgically replanted finger is that its surival in the recipient bed is predicated on functioning intravascular circulation. Although considerable progress has been made in the techniques for microvascular replantation of amputated fingers, the replantation of an amputated fingertip is difficult because digital arteries branch into small arteries. This is in addition to digital veins that run from both sides of the nail bed to the median dorsal sides, which are difficult to separate from the immobile soft tissue. Furthermore, even with the most technically skilled microsurgeon, replantation failure often occurs, especially in severe injury cases. Therefore, the technique is not the only protection against failure, and a new strategy of fingertip reattachment is needed. From March of 1997 to December of 1999, 12 fingers of 11 patients with zone 1 or zone 2 fingertip amputations that were reattached microsurgically but were compromised were deepithelialized, reattached, and then inserted into the abdominal pocket. All had been complete amputations with crushing injuries. Approximately 3 weeks later, the fingers were depocketed and covered with a skin graft. Of the 12 fingers, 7 survived completely and 3 had partial necrosis on less than one-third the volume of the amputated part. The complete survival rate was approximately 58 percent. The results of the above 10 fingers were satisfactory from both functional and cosmetic aspects. The authors believe that this high success rate was achieved because the deepithelialized finger pulp was placed in direct contact with the deep abdominal fascia, which was equipped with plentiful vascularity, not subcutaneous fat. In addition, the pocketing was performed promptly before necrosis of the compromised fingertip occurred. From the results of this study, it is clear that this new method is useful and can raise the survival rate of an amputated fingertip.     

The boomerang flap in managing injuries of the dorsum of the distal phalanx

Finding an appropriate soft-tissue grafting material to close a wound located over the dorsum of a finger, especially the distal phalanx, can be a difficult task. The boomerang flap mobilized from the dorsum of the proximal phalanx of an adjacent digit can be useful when applied as an island pedicle skin flap. The vascular supply to the skin flap is derived from the retrograde perfusion of the dorsal digital artery. Mobilization and lengthening of the vascular pedicle are achieved by dividing the distal end of the dorsal metacarpal artery at the bifurcation and incorporating two adjacent dorsal digital arteries into one. The boomerang flap was used in seven individuals with injuries involving the dorsal aspect of the distal phalanx over the past year. Skin defects in all patients were combined with bone,joint, or tendon exposure. The authors found that the flap was reliable and technically simple to design and execute. This one-step procedure preserves the proper palmar digital artery to the fingertip and has proven valuable for the coverage of wide and distal defects because it has the advantages of an extended skin paddle and a lengthened vascular pedicle. When conventional local flaps are inadequate, the boomerang flap should be considered for its reliability and low associated morbidity.     

Digital glomus tumors: a 29-year experience with a lateral subperiosteal approach

The excision of distal digital glomus tumors has traditionally been performed directly over the involved nail bed. This can lead to nail deformities that are often unacceptable for the surgeon and the patient. The authors describe their experience with successful excision of digital glomus tumors using a lateral subperiosteal approach, which creates a dorsal flap. In 29 years, 19 patients were diagnosed with digital glomus tumors. All patients underwent excision using the lateral subperiosteal approach. The mean tumor size was 0.52 cm. The tumors were located on the pulp of the distal phalanx in two patients (10.5 percent) and subungually in 17 patients (89.5 percent). In all patients, preoperative clinical diagnosis was confirmed postoperatively with the biopsy result. Complications occurred in only two patients and included one paronychia and one temporary nail loss. The overall recurrence rate was 15.7 percent. All patients remained asymptomatic after surgery and regained full active and passive range of motion. There were no nail deformities by this approach. This technique represents a safe and effective approach to excising digital glomus tumors.     

Sensory reconstruction of the fingertip using the bilaterally innervated sensory cross-finger flap

The authors present a series of 15 patients with large soft-tissue defects of the fingertips as a prospective, nonrandomized study. In all cases, reconstruction was achieved using a bilaterally innervated sensory cross-finger flap. This sensory fasciocutaneous flap relies on the dorsal branch of the proper digital nerves, which branch off at the level of the head of the proximal phalanx; sensory supply to the dorsal skin of the middle phalanx is thus ensured. The reconstructive procedure consists of two steps. First, the contralateral dorsal branch of the proper digital nerve is elevated with the flap at proximal interphalangeal joint level. Microsurgical coaptation is performed to the proximal nerve stump of the injured fingertip. After 3 weeks, when the pedicle is dissected, the second nerve is dissected and coapted. Clinical results were evaluated after 12 months. Because the regenerative distance is only 1.5 to 2.5 cm, good sensory regeneration should be expected. In nine of 16 flaps, sensory quality of S2+ (Highet) was present in the flap after 3 weeks. After 12 months, two-point discrimination was present in all patients, the values ranging between 2 and 6 mm (for two-point discrimination), with an average of 3.6 mm. The rate of complications was low. With acceptable additional operative action, a good functional result can be achieved. The indications of this method are discussed in comparison with other methods of fingertip reconstruction.     

Fingertip replantation using the subdermal pocket procedure

Restoration of finger length and function are the goals of replantation after fingertip amputation. Methods include microsurgical replantation and nonmicrosurgical replantation, such as composite graft techniques. To increase the survival rates for composite grafts, the subcutaneous pocket procedure has been used as a salvage procedure. The subdermal pocket procedure, which is a modification of the subcutaneous pocket procedure, was used for replantation of 17 fingertips in 16 consecutive patients. Eight fingertips experienced guillotine injuries and the other nine fingertips experienced crush injuries. Revascularization of one digital artery without available venous outflow was performed for six fingers, and composite graft techniques were used for the other 11 fingers. The success rate was 16 of 17 cases. The difference in success rates for guillotine versus crush injuries was statistically significant. Comparison of patients with arterial anastomoses and patients without arterial anastomoses also indicated a statistically significant difference. Thirteen fingertips survived completely. One finger, demonstrating complete loss and early termination of the pocketing procedure, was amputated on the eighth postoperative day. Two fingers were partially lost because of severe crushing injuries. One finger demonstrated partial loss of more than one quarter of the fingertip, which required secondary revision, because the patient was a heavy smoker. The pocketing period was 8 +/- 1 days (mean +/- SD, n = 6) for the fingers revascularized with one digital arterial anastomosis and 13.3 +/- 1.9 days (n = 10) for the fingers successfully replanted with composite graft techniques. The mean active range of motion of the interphalangeal joint of the three thumbs was 65 +/- 5 degrees, and that of the distal interphalangeal joint of the other 11 fingers was 51 +/- 11 degrees. The static two-point discrimination result was 6.4 +/- 1.0 mm (n = 14) after an average of 11 +/- 5 months of follow-up monitoring. Compared with other methods, the subdermal pocket procedure has the advantages of exact subdermal/subdermal contact, a shorter pocketing period, and more feasible observation. The method can offer an alternative salvage procedure for fingertip amputations with no suitable vessels available for microsurgical replantation.     

A versatile one-stage neurovascular flap for fingertip reconstruction: the dorsal middle phalangeal finger flap.

The dorsal middle phalangeal finger flap is an extremely reliable flap that is indicated for fingertip injuries which require sensory reconstruction. This flap originates from the dorsum of the middle phalanx of the finger and is elevated with a vascular pedicle of the digital artery and the dorsal branch of the digital nerve. After transfer of the flap to the injured site, epineural neurorrhaphy is done between the digital nerve and the dorsal sensory branch of the flap. This flap can be thought of as an island flap of the innervated cross-finger flap that provides excellent sensory recovery and aesthetic improvement. We used this flap in a series of eight consecutive patients and were able to follow up seven patients for longer than 6 months (mean follow-up time 10.7 months). All patients achieved measurable two-point discrimination, with an average of 4.9 mm in the moving two-point discrimination. In this study, we report our consecutive series of the dorsal middle phalangeal finger flap and its versatile utility.     

Nail lengthening and fingertip amputations

Fingertip injuries can be treated in different ways, including shortening with primary closure, skin grafts, and local or distant flaps. Nail bed involvement complicates fingertip reconstruction and may influence the choice of treatment. Local flaps can usually replace the pulp and provide a satisfactory functional and aesthetic result, whereas reconstruction of the fingernail apparatus is more difficult. In the period between 1998 and 2001, 12 fingertip injuries with nail bed involvement were treated with a combination of local flaps (Tranquilli-Leali and Venkataswami flaps) and the eponychial flap. The eponychial flap described by Bakhach is a backward cutaneous translation flap that lengthens the nail plate and restores a good appearance of the nail apparatus. This technique is simple to use and can be used with different flaps for pulp reconstruction.     

Delayed primary reconstruction of subtotal nail bed loss using a split-thickness nail bed graft on decorticated bone

Split-thickness nail bed grafting is the accepted method of treatment for injuries involving loss of nail bed tissue. The nail bed of the great toe may be used without donor-site morbidity, and nail bed grafting may be combined with other procedures for fingertip reconstruction. A case of fingertip avulsion injury with loss of the nail plate, nail bed, and periosteum over the exposed distal phalanx of the thumb was reconstructed by a split-thickness nail bed graft placed directly on granulating decorticated bone. The length, appearance, and function of the injured dominant thumb were preserved.     

Does the nail bed really regenerate?

From observations of nail bed injuries, the regeneration of the nail bed seemed evident. The nail bed regenerated well in the presence of the nail matrix and poorly in its absence, suggesting that the nail bed regenerated from the nail matrix. Full-thickness skin graft or flap coverage of nail bed defects resulted in the good nail bed regeneration. The nail bed grew back, pushing the graft or the flap distally. The regenerated nail beds were about 70 percent of normal size in guillotine-type amputations and about 90 percent in the presence of an intact distal phalanx. The difference between full- and split-thickness skin grafts seemed to be adherence to the phalangeal bone, the former giving way to the advancing nail bed and the latter staying in the way. In addition, the destination of the moving nail bed cells was discussed.     

The effect of torque direction and cylindrical handle diameter on the coupling between the hand and a cylindrical handle

Pheasant and O'Neill's torque model (1975) was modified to account for grip force distributions. The modified model suggests that skin friction produced by twisting an object in the direction of fingertips causes flexion of the distal phalanges and increases grip force and, thus, torque. Twelve subjects grasped a cylindrical object with diameters of 45.1, 57.8, and 83.2 mm in a power grip, and performed maximum torque exertions about the long axis of the handle in two directions: the direction the thumb points and the direction the fingertips point. Normal force on the fingertips increased with torque toward the fingertips, as predicted by the model. Consequently, torque toward the fingertips was 22% greater than torque toward the thumb. Measured torque and fingertip forces were compared with model predictions. Torque could be predicted well by the model. Measured fingertip force and thumb force were, on average, 27% less than the predicted values. Consistent with previous studies, grip force decreased as the handle diameter increased from 45.1 to 83.2 mm. This may be due not only to the muscle length-strength relationship, but also to major active force locations on the hand: grip force distributions suggest that a small handle allows fingertip force and thumb force to work together against the palm, resulting in a high reaction force on the palm, and, therefore, a high grip force. For a large handle, fingertip force and thumb force act against each other, resulting in little reaction force on the palm and, thus, a low grip force.     

An innervated cross-finger flap for fingertip reconstruction

An innervated cross-finger flap for treatment of severe fingertip injuries is described. With this method, the dorsal skin over the middle phalanx, together with its sensory nerve, is transferred as a compound skin-nerve flap. A neurorrhaphy is performed between this nerve and the cut end of the digital nerve at the injury site. Seven of eight patients (88 percent) treated with this method (mean follow-up time 14.4 months) achieved measurable two-point discrimination. The average for those who did was 4.8 mm. A group of patients with similar injuries treated with standard cross-finger flaps exhibited slower sensory return that progressed to a lower level. In this group (mean follow-up time 16.3 months), three of six (50 percent) achieved measurable two-point discrimination with a mean value of 9 mm.     

Heterodigital arterialized flaps for large finger wounds: results and indications

Deep defects of the hand and fingers with an unhealthy bed exposing denuded tendon, bone, joint, or neurovascular structures require flap coverage. However, the location and size of the defects often preclude the use of local flap coverage. Free-flap coverage is often not desirable either, because the recipient vessels may be unhealthy from surrounding infection or trauma. In such situations, a regional pedicled flap is preferable. A solution to this is the heterodigital arterialized flap. This flap is supplied by the digital artery and a dorsal vein of the finger for venous drainage. Unlike the neurovascular island flap, the digital nerve is left in situ in the donor finger, thus avoiding many of the neurologic complications associated with the Littler flap. The digital artery island flap is centered on the midlateral line of the donor finger. It extends from the middorsal line to the midpalmar line. The maximal length of the flap is from the base of the finger to the distal interphalangeal joint. By preserving the pulp and the digital nerve, a sensate pulp on the donor finger remains that reduces donor-finger morbidity and also preserves fingertip cosmesis. Twenty-nine flaps were performed in 29 patients and the outcomes in the donor finger and the reconstructed finger were reviewed. The flap survival was 100 percent. There were no cases of flap ischemia or flap congestion. Good venous drainage of the flap through the additional dorsal vein was helpful in preventing the occurrence of early postoperative venous congestion, which is common in island flaps of the fingers, which depend on only the venae comitantes for drainage. Donor-finger morbidity, measured in terms of range of motion and two-point discrimination in the pulp, was minimal. Ninety-seven percent of the donor fingers achieved excellent or good total active motion according to the criteria of Strickland and Glogovac. Pulp sensation in the donor fingers was normal in 28 of the 29 donor fingers. No cold intolerance of the donor finger or the adjacent finger is reported in this series.     

Replantation of fingertip amputation by using the pocket principle in adults

There are several treatment modalities for zone 1 or zone 2 fingertip amputations that cannot be replanted by using microsurgical techniques, such as delayed secondary healing, stump revision, skin graft, local flaps, distant flaps, and composite graft. Among these, composite graft of the amputated digit tip is the only possible means of achieving a full-length digit with a normal nail complex. The pocket principle can provide an extra blood supply for survival of the composite graft of the amputated finger by enlarging the area of vascular contact. The surgery was performed in two stages. The amputated digit was debrided, deepithelialized, and reattached to the proximal stump. The reattached finger was inserted into the abdominal pocket. About 3 weeks later, the finger was removed from the pocket and covered with a skin graft. We have consecutively replanted 29 fingers in 25 adult patients with fingertip amputations by using the pocket principle. All were complete amputations with crushing or avulsion injuries. Average age was 33.64 years, and men were predominant. The right hand, the dominant one, was more frequently injured, with the middle finger being the most commonly injured. Of the 29 fingers, 16 (55.2 percent) survived completely and 10 (34.5 percent) had partial necrosis less than one-quarter of the length of the amputated part. The results of the above 26 fingers were satisfactory from both functional and cosmetic aspects. Twenty of the 29 fingers, which had been followed up for more than 6 months (an average of 16 months), were included in a sensory evaluation. Fifteen of these 20 fingers (75 percent) were classified as "good" (static two-point discrimination of less than 8 mm and normal use). From the overall results and our experience, we suggest that the pocket principle is a safe and valuable method in replantation of zone 1 or zone 2 fingertip amputation, an alternative to microvascular replantation, even in adults.     

Soft-tissue injuries of the fingertip: methods of evaluation and treatment. An algorithmic approach

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the anatomy of the fingertip. 2. Describe the methods of evaluating fingertip injuries. 3. Discuss reconstructive options for various tip injuries. SUMMARY: The fingertip is the most commonly injured part of the hand, and therefore fingertip injuries are among the most frequent injuries that plastic surgeons are asked to treat. Although microsurgical techniques have enabled replantation of even very distal tip amputations, it is relatively uncommon that a distal tip injury will be appropriate for replantation. In the event that replantation is not pursued, options for distal tip soft-tissue reconstruction must be considered. This review presents a straightforward method for evaluating fingertip injuries and provides an algorithm for fingertip reconstruction.     

Modeling of time-dependent force response of fingertip to dynamic loading

An extended exposure to repeated loading on fingertip has been associated to many vascular, sensorineural, and musculoskeletal disorders in the fingers, such as carpal tunnel syndrome, hand-arm vibration syndrome, and flexor tenosynovitis. A better understanding of the pathomechanics of these sensorineural and vascular diseases in fingers requires a formulation of a biomechanical model of the fingertips and analyses to predict the mechanical responses of the soft tissues to dynamic loading. In the present study, a model based on finite element techniques has been developed to simulate the mechanical responses of the fingertips to dynamic loading. The proposed model is two-dimensional and incorporates the essential anatomical structures of a finger: skin, subcutaneous tissue, bone, and nail. The skin tissue is assumed to be hyperelastic and viscoelastic. The subcutaneous tissue was considered to be a nonlinear, biphasic material composed of a hyperelastic solid and an invicid fluid, while its hydraulic permeability was considered to be deformation dependent. Two series of numerical tests were performed using the proposed finger tip model to: (a) simulate the responses of the fingertip to repeated loading, where the contact plate was assumed to be fixed, and the bone within the fingertip was subjected to a prescribed sinusoidal displacement in vertical direction; (b) simulate the force response of the fingertip in a single keystroke, where the keyboard was composed of a hard plastic keycap, a rigid support block, and a nonlinear spring. The time-dependent behavior of the fingertip under dynamic loading was derived. The model predictions of the time-histories of force response of the fingertip and the phenomenon of fingertip separation from the contacting plate during cyclic loading agree well with the reported experimental observations.     

Adjacent and spontaneous neurotization after distal digital replantation in children

In an exclusively pediatric population, this retrospective study examined the functional and aesthetic results after distal replantation without nerve suture. The aim was to demonstrate, in the child, the presence of spontaneous nervous regeneration resulting in a fingertip pulp with discriminatory sensation. Eight amputations in eight children with a mean age of 9 years and 2 months on the day of the accident were reviewed. The cases were managed by a single surgeon over a period of 8 years and were collected from two different hand centers. The patients were then examined by a different surgeon, and the data were collected. Sensibility was evaluated using the Weber, Semmes-Weinstein, and wrinkle tests. The results were excellent, with mean values of 4.6 mm for the Weber test, 3.3 for the Semmes-Weinstein test, and a positive wrinkle test in all subjects. All patients thus recovered discriminatory sensation with minimal aesthetic sequelae. The usual factors adversely affecting the results of the replantation (ischemic time, level and mechanism of the amputation, and quality of the venous return) were examined, but no statistical analysis was performed because of the small sample size. This study demonstrates the presence of the clinical phenomenon of adjacent neurotization in the absence of nerve repair. It thus confirms that children are excellent candidates for replantation of the distal extremities, even when nerve suture is not performed.     

Finger length and distal finger extent patterns in humans

The fingers in the adult human hand differ in length and in distal extent. The literature agrees that in the clear majority of males, the distal extent of the ring finger tends to be relatively greater (using the middle finger as standard) than the index finger. However, the results for females vary considerably, with some studies reporting that females show a similar pattern to that of males, while others suggest that the prevalence of a longer index finger is relatively or absolutely more common in females. We provide a review of the literature, and a set of data for both finger length and distal fingertip extent of the finger for a contemporary cohort of young adult females and males (n = 502). Finger length measures favor the ring finger of both sexes, with smaller between-finger differences for females than for males. However, while the distal fingertip extent favors the ring finger of both hands in males, in females the left hand shows no significant differences, and the right hand shows a small index finger advantage. Thus, the sexual dimorphism in finger measures is more strongly expressed in the distal extent of fingertips than in the length of fingers. The sex differences in distal fingertip extent derive from the index finger only, with a lesser distal extent of the index finger, relative to the middle finger, in males than in females.     

A New Surgical Technique for Polysyndactyly of the Toes without Skin Graft

Reconstruction for polysyndactyly of the toes aims at cosmetic improvement. A previous method that uses a skin graft has inherent disadvantages of mismatched pigmentation between the graft and the surrounding skin and scar formation at the donor site. The authors' new improved surgical technique for the treatment of polysyndactyly of the toes does not require a skin graft and therefore avoids these problems. The authors designed a subcutaneous flap from the distal portion of a rectangular flap of skin from the dorsal side of the interdigital webbing and moved the former flap to the sidewall of the base of a toe. Both flaps are the same size; therefore, an interdigital space had to be of sufficient size to accommodate both of them. To ensure an adequate blood supply to the flap, careful handling of the subcutaneous flap is essential for success. This procedure can apply to polysyndactyly of the fourth, fifth, and sixth toes when the fourth and fifth toes adhere over the distal side of the distal interphalangeal joint and when the skin on the dorsal side of the fifth toe, regarded as the excessive one, is at lease twice the size of the dorsal rectangular flap. Ten patients with polysyndactyly of the toe were treated with this method. Aesthetically good results were obtained.     

Distally based dorsal forearm fasciosubcutaneous flap

Use of a local flap is often required for the reconstruction of a skin defect on the dorsum of the hand. For this purpose, a distally based dorsal forearm fasciosubcutaneous flap based on the perforators of the posterior interosseous artery was developed. From 1997 until 2002, this flap was used to reconstruct skin defects on the dorsum of the hand in nine patients at Chonnam National University Medical School. The sizes of these flaps ranged from 10 to 14 cm in length and from 5 to 7 cm in width. The flaps survived in all patients. Marginal loss over the distal edge of the flap was noted in one patient. Three flaps that developed minimal skin-graft loss were treated successfully with a subsequent split-thickness skin graft. The long-term follow-up showed good flap durability and elasticity. The distally based dorsal forearm fasciosubcutaneous flap is a convenient and reliable alternative for reconstructing skin defects of the dorsum of the hand involving vital structure exposure. It obviates the need for more complicated and time-consuming procedures.