Acknowledgment:
I would like to acknowledge the contributions of Dean S. Louis, Mark Bagg, Brian T. Carlsen, and, in particular, Peter J. L. Jebson.
The most common cause of an amputated finger or thumb is accidental traumatic injury. In other cases, digital amputation may be necessary because of congenital deformity or acquired pathologic conditions (e.g., malignant tumors or chronic infection). Other indications may arise as sequelae of trauma, such as stiffness or debilitating pain, or revision surgery may be needed to improve the fit of a prosthesis. Amputations may occasionally be self-inflicted because of a psychological disturbance or in an attempt to defraud an insurance company. Return of function is the primary consideration after an amputation; for this reason, the surgeon should be aware of the patient’s occupation and vocations. The surgeon should express empathy and gauge the patient’s emotional response following the amputation. Failure to appreciate the patient’s attitude and ability to adjust to the injury may compromise an otherwise successful operative procedure.
As surgeons, we tend to be much influenced by the experience of mentors early in our careers, and later, our own expanding experience is helpful. We hold fast to methods that prove satisfactory in our hands and quickly seek alternatives to procedures that yield unsatisfactory outcomes. The numerous articles referenced in this chapter attest to the reasoned contributions of many authors who treat seemingly similar amputation situations by widely disparate methods. For some surgeons, the more technically demanding procedures have great appeal. Others prefer the simplest yet most effective procedure, such as shortening of bone followed by primary closure, or healing by secondary intention. There is clearly no gold standard technique for every clinical scenario.
The goals of amputation surgery in the upper extremity should be (1) preservation of functional length, (2) provision of durable skin coverage, (3) preservation of useful sensibility, (4) avoidance of symptomatic neuromas, (5) prevention of adjacent joint contractures, (6) prevention of morbidity, so that the patient has the fewest complications possible, (7) allowance of early prosthetic fitting when applicable, and (8) allowance of early return to work, play, and activities of daily living.
Any amputation in a child, whose ultimate role in life is yet undefined, should be approached with a conservative attitude. Late reconstruction is generally preferable to any early radical ablative procedure. Adults with well-defined functional roles may be better served by a more definitive approach that will accelerate their functional rehabilitation.
At times, deciding whether to perform limb salvage or amputation may be difficult. Consultation with an experienced and knowledgeable colleague is helpful and should always be documented in the patient’s medical record. It will reassure the patient and family and will be helpful should medicolegal matters ensue. Photographs of the injured extremity before amputation are useful to document the severity of the injury. Although replantation or attempted salvage of a severely traumatized limb is an option at times, it may be more of a technical triumph than a procedure done in the patient’s best interests. The enthusiasm for the successful technical accomplishment of replanting an amputated finger part versus closure and early rehabilitation has been dampened by poor patient outcomes at a greater financial cost, including lost wages and the cost of hospitalization and therapy. Cold intolerance can be a substantial problem for patients following an amputation, but the symptoms tend to improve over time.
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Maintain length
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Restore sensation
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Provide stable soft tissue coverage
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Prevent symptomatic neuromas
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Prevent adjacent joint contractures
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Allow early prosthetic fitting when applicable
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Allow early return to activities of daily living
Digital Tip Amputations
An amputation of the fingertip is the most common type of amputation seen in the upper extremity and at the same time provokes the greatest controversy because of the multitude of treatment options. Multiple techniques have been developed to advance local skin or transfer soft tissue to ensure coverage of an area where bone is exposed. The surgeon, in consultation with each patient, must choose the type of coverage that appears to be most appropriate for that individual’s needs and within the technical abilities of the surgeon. Regardless of choice of treatment, the goals of preserving functional length and restoring adequate sensibility remain constant. When one is comparing the various treatment options available or looking for guidance, the injury zone classification systems of Hirase, Allen, and Tamai provide a useful frame of reference ( Figure 49.1 ).
Digital Tip Amputations With Skin or Pulp Loss Only
When the digital tip is amputated, the geometry of the defect dictates the various treatment possibilities. The loss may be transverse or oblique, with more volar skin loss than dorsal skin loss, or the reverse may be true. Some slicing amputations may result in skin loss primarily from the ulnar or radial side of the digit and may spare the distal tip.
Nonmicrosurgical Reattachment or Composite Graft
If the amputated part is available and not highly contaminated, it may be cleansed and reattached as a “biologic cover.” This is an effective approach in children with injuries distal to the distal interphalangeal (DIP) joint in which the tip is defatted and repaired to the stump without microsurgery. If there is bony involvement, stability may be afforded by repair of the amputated tip with absorbable sutures, Kirschner wires, or an 18-gauge needle. The nail plate is removed and the nail plate repaired. Timing of repair is crucial. Moiemen and Elliot noted that those repaired within 5 hours after injury had a 61% survival rate compared with none after this time point. The tip may become necrotic but should be left in situ as long as there is no developing infection because the tissue acts as a biologic dressing. Similar success has not been noted within adults. Heistein and Cook reported on 53 patients who underwent composite tissue grafting of injuries distal to the DIP joint. The success rate was 43% for injuries between the DIP joint and the eponychium and 58% for injuries distal to the eponychium. Factors linked to suboptimal results were smoking, age older than 18 years, alcohol use, presence of diabetes, and crush injury. In an effort to improve survival, Chen and colleagues reported on a technique whereby the distal amputated tip was defatted and deepithelialized and the bone excised in patients who sustained either a crush or sharp transection injury. The survival rate was higher than 93% with an average two-point discrimination of 6.3 mm after 6 months. Over 90% of patients were happy with the cosmetic appearance and 86% were able to use the finger normally at work.
Dressing Changes and Healing by Secondary Intention
Healing by secondary intention with dressing changes is one of the best options for a tip amputation without exposed bone. This technique is especially applicable when the amputated part is unavailable or cannot be used. This technique is simple, inexpensive, and effective, regardless of patient age ( Figure 49.2 ). Healing by secondary intention is most applicable for wounds with skin loss of 1.5 cm or less; healing will occur by reepithelialization over 3 to 4 weeks with return of normal sensation and two-point discrimination. Indeed, recovery of sensation tends to be better than with other forms of surgical reconstruction. Dressing changes can also be used to treat wounds where there is additional loss of subcutaneous tissue of similar size, but it may take 1 to 2 months to heal by secondary intention. The patient performs daily dressing changes and local wound care. Protective splinting may be used to protect the healing wound. Patients can be referred to hand therapists within the first few days after injury to use modalities such as MIST ultrasound therapy (Celleration, Inc., Eden Prairie, MN) to encourage granulation tissue formation. Ultrasound works by reducing the bacterial load and promoting tissue regeneration by increasing angiogenesis, release of growth factors, and collagen deposition. Patients are encouraged to work on the range of motion to avoid joint stiffness and/or contractures.
Bojsen-Moller and colleagues reviewed a series of 134 digital tip injuries in 110 patients who were treated by dressing changes, shortening of the digit, or skin grafting. They observed that nonoperative treatment was almost always uncomplicated, whereas in some of the surgical cases, there were complications such as infection or graft failure that actually prolonged treatment. In addition, there was no significant difference in time off work between the treatment groups. The authors concluded that management of an amputation by shortening and primary closure was inferior to skin grafting or dressing changes. Allen reported on 46 patients with 49 fingertip injuries from the lunula and distal phalanx. If the distal phalanx was exposed it was trimmed back to allow soft tissue to cover it. Forty-five patients thought their results were very good or good, 3 thought they were acceptable, and 1 deemed the result as poor. Four of the 49 injuries required secondary surgery, 3 for nail growth problems and 1 because of lack of soft tissue coverage. The average two-point discrimination was 6 mm, and the average time off work ranged from 18 to 26 days. None of the patients had any joint stiffness, although 50% did experience cold intolerance, which was marked in 10%. Weichman and colleagues compared the outcomes of patients with fingertip injuries treated nonoperatively with those treated operatively (nail removal, revision amputation, or grafting with full-thickness grafts or local flaps, such as the “V-Y” advancement, cross-finger, thenar, or first dorsal metacarpal flap). Those who had surgery had larger wounds (3.3 cm versus 1.75 cm), volar oblique lacerations (50% versus 9%), exposed bone (81% versus 35%), and a distal phalanx fracture (81% versus 47%). The authors found that patients requiring operative treatments had more time off work (4.3 weeks compared with 2.9 weeks), which is likely related to the extent of injury.
Primary Closure
Primary closure may be performed if the repair is without tension at the wound edges. Often this can be difficult because there tends to be a lack of sufficient mobile dermis for a tension-free primary repair. Primary closure, when possible, was shown in the series by Holm and Zachariae to give results equivalent to conservative healing by secondary intention. However, in the series reported by Sturman and Duran, 51% of the patients complained of tenderness and had some disability. Shortening of the bone may allow primary closure; however, the surgeon needs to perform traction neurectomies to prevent a symptomatic neuroma. A nail bed ablation is performed if the injury is at or through the lunula. The entire germinal and sterile matrix is excised, which requires scraping the dorsal cortex of the distal phalanx with a curette and excising the tissue on the undersurface of the proximal nail fold and in the paronychial folds. The patient needs to be informed of the potential risk of a neuroma and a nail horn at the time of closure because these entities can become symptomatic several months after the procedure.
Split-Thickness Grafting
Split-thickness skin grafting has been a popular method for coverage of the exposed pulp when there is a well-vascularized recipient bed. Split-thickness grafts contract more than full-thickness grafts and are limited by the fact they cannot be placed directly onto bone or tendon devoid of its paratenon. In a study by Holm and Zachariae, only 56% of the patients who had undergone skin grafting considered their results to be good after 5 years of follow-up, compared with 90% of patients treated conservatively with a wound that was permitted to heal by secondary intention. The most important complaints after skin grafting were induration and fissuring of the skin and reduced sensibility in the area of the graft, as well as complaints about the donor site. Cold sensitivity was present in 39% of the patients treated conservatively and in 33% of those who received a split-thickness skin graft. Hypoesthesia was present in 26% of those treated conservatively and in 67% of those who were treated with a skin graft. The authors concluded that split-thickness skin grafting offered no advantages for fingertip coverage.
Sturman and Duran monitored 235 patients with a fingertip amputation for a minimum of 1 year and reported their late outcomes. Of the patients who had split-thickness skin grafts, 70% reported tenderness in the area of the graft, and in 41%, the tenderness was considered to be marked. Cold sensitivity was present in 49% of the patients who had split-thickness skin grafts, including 27 of the 53 who had thumb or index tip amputations. Fifty-nine percent of the latter group avoided the injured digit when the pickup test was administered. Thirty-two percent of them noted diminished touch sensibility. The average two-point discrimination measured was 5 mm, considerably greater than the normal 2 mm.
Digital Tip Amputations With Exposed Bone
When bone is exposed, the question becomes whether length should be preserved (necessitating coverage of the site) or whether sacrifice of length is justifiable. An important variable is the extent of nail matrix injury. The development of a hooked nail is avoided by careful attention to wound closure and avoidance of the loss of bony support for the nail bed. Closure of a fingertip amputation by pulling the nail bed over the distal phalanx should be avoided. If a satisfactory amount of distal phalanx is absent, the nail bed must be trimmed back to the same level at the end of the bone so that it does not curve over the end of the bone and subsequently lead to the development of a hooked nail. A nail bed ablation is performed if the injury is at or through the lunula. Given that the primary aim is to restore function to the injured individual, some wounds with minimal exposed bone may be converted to wounds with no bone exposed by rongeuring followed by closure. My preference for closure is to use absorbable 3-0 suture to avoid the need for suture removal because often sutures may be covered with thick eschar and painful to remove. Alternatively, the wound may be left to heal by secondary intention, ensuring that the nail bed is supported by underlying bone. Antibiotics are not routinely prescribed if there has been adequate wound débridement without gross contamination. Patients are seen after 1 to 2 weeks and are sent to occupational therapy to work on edema control and range of motion. Tip desensitization is started once the wound is healed and stable. Many of these injuries are work related, and most manual workers are able to return to duty without restrictions by 6 to 8 weeks after injury.
If there is no possibility of direct closure of the wound, bony coverage may be accomplished by one of several described techniques, each with its own merits and limitations.
Semiocclusive Dressings
Studies have demonstrated successful treatment with the use of an occlusive dressing. The dressing should be applied within a few days of the injury. Self-adhesive OpSite or Flexifix film (Smith and Nephew, London, UK) is used. The dressing is changed weekly until epithelialization has been completed. Hoigne and associates reported on a series of 17 patients with an exposed distal phalanx; patient satisfaction was good with regeneration of approximately 90% of the original soft tissue volume with an average two-point discrimination of 4 mm. The average duration of dressing use was 6.5 weeks. There were no cases of bone regeneration or infection. Complications included a single case of a nail horn and posttraumatic neuroma.
Bilayer Matrix Wound Dressing
The Integra Bilayer Matrix Wound Dressing (BMWD) (Integra Life Sciences, Plainsboro, NJ) is an acceptable alternative to flap coverage. The graft consists of an acellular dermal matrix composed of bovine collagen covered by a silicone layer. It is designed to act as a skin regeneration scaffold that allows the host’s cells to grow into the dermal template. They can be placed directly onto bone or tendon once the wound bed is clean and devoid of contamination. It can be sutured in place and its “take” encouraged with bolster or negative pressure dressings. The graft is normally applied as part of a two-stage procedure in which autologous skin graft is applied 3 to 4 weeks after matrix application. Taras and coworkers used two-stage grafting in digital injuries with exposed bone, joint, tendon, or hardware in 21 digits. The area of Integra application ranged from 1 to 12 cm 2 . Twenty of 21 digits demonstrated complete incorporation of the dermal matrix, and following skin grafting, 16 of 20 digits demonstrated complete incorporation. Single-stage use avoids the morbidity of skin grafting and is the same as healing by secondary intention because the healing process relies on both wound contraction and reepithelialization. In a series of nine patients with an average defect of 2.3 cm 2 (range, 1 to 3.2 cm 2 ), Jacoby and colleagues demonstrated high patient satisfaction, with a mean static two-point discrimination of 9.6 mm (4.6 mm for the opposite unaffected finger). One patient developed an early infection, followed by a hook nail deformity 18 months after treatment. There were no other complications. The Integra BMWD is more expensive than a semiocclusive dressing or healing by secondary intention. However, the graft may be placed directly on bone, preserving critical length and obviating the need for flap coverage with the associated inconvenience and morbidity ( Figure 49.3 ).
Atasoy-Kleinert Volar “V-Y” Flap
In 1970, Atasoy and associates described a triangular volar “V-Y” advancement flap ( Figure 49.4 ) for reconstruction of the distal pad with preservation of length when bone is exposed. It is indicated for dorsal oblique or transverse distal fingertip amputations beyond the midpart of the nail. The flap is contraindicated in injuries in which there is an oblique amputation with more palmar skin loss than dorsal skin loss and in situations in which there is extensive skin loss as a result of the injury.
Digital anesthesia is administered before preparation of the wound. After surgical preparation of the hand, a Tourni-Cot (Mar-Med, Grand Rapids, MI) is used to exsanguinate the digit and simultaneously provide tourniquet ischemia. Alternatively, the finger is elevated and a Penrose drain tied at the base of the digit. A pattern may be made to cover the dimensions of the defect and then transposed proximally to the cut edge of the skin that is to be advanced. The base of the triangle will be the distal cut edge, and an appropriate triangle of skin is made according to the pattern, with the apex of the triangle being at the DIP flexion crease. The two sides of the triangle should be at least 1.5 times the length of the desired advancement. Only the full thickness of the skin is cut. The digital nerves and blood vessels of the flap are preserved. Its blood supply is from the small arterial branches of the digital arteries distal to the trifurcation of the digital nerves. Separation between the flexor sheath and subcutaneous tissue is performed by dividing the fibrous septae that anchor the subcutaneous tissue to the bone, which facilitates advancement of the flap distally. The skin of the flap must be connected to the subcutaneous tissue to maintain its viability. The base of the triangle is carefully contoured and sutured to the nail bed or remaining nail, and the resulting “V” incision on the palmar aspect of the digit is closed, thus converting it to a “Y” (see Figure 49.4 ). The Tourni-Cot or Penrose drain is removed prior to flap insetting to ensure its viability. The flap can be adequately mobilized up to 1 cm and if necessary defatted to facilitate tension-free skin closure. Postoperative management consists of sterile dressings over the surgical sites that allow early motion of all adjacent joints. Active motion and digital usage are advanced as healing ensues over the next few weeks.
In their initial report, Atasoy and associates stated that 56 of 61 patients available for follow-up had normal sensation and motion. However, a follow-up study conducted by Frandsen found hypoesthesia or dysesthesia in 7 of 10 patients with triangular volar flaps. Four of the 10 patients had subjective complaints of cold intolerance, and 5 of the patients also had difficulty grasping objects. Conolly and Goulston had unsatisfying results in 4 of 7 patients treated by this technique. The results were deemed unsatisfactory because of persistent paresthesias or impaired sensibility. Tupper and Miller reported diminished sensibility in all 16 of their patients. Eight of their patients reported hypersensitivity, particularly cold intolerance.
Kutler Lateral “V-Y” Flaps
Kutler described the use of “V-Y” advancement flaps for digital tip injuries ( Figure 49.5 ). The technique involves advancing two triangular flaps from lateral positions to cover the tip of the digit.
Preparation of the digit is similar to that used in the Atasoy technique. The tip of the digit is débrided as necessary. Two triangular flaps are developed from the midlateral aspect of each side of the digit, and the incisions are made just down through the dermis. The subcutaneous tissue is similarly mobilized from the phalanx on a deep plane by dividing the fibrous septae. Both triangles are advanced to the midline distally and sutured together. The “V” apex of the triangle is closed in a “Y” fashion, and the surrounding edges and nail bed, or nail, are carefully sutured to the distal edges of the advanced flaps (see Figure 49.5 ). This flap can only be advanced up to 3 to 4 mm. Haddad reported on a series of 20 patients treated with this technique and stated that slight skin necrosis occurred at the edges if the flaps were too large. Subjective evaluation in a series of 22 patients was reported by Freiberg and Manktelow, who noted mild hypersensitivity and numbness in 7 of 22 patients. Frandsen reported a follow-up study of 14 patients who underwent Kutler’s technique and found subjective complaints of coldness in 8 patients (57%), tenderness on percussion in 10 (71%), difficulty in grasping small objects in 6 (43%), and slight hypoesthesia or dysesthesia in 10 (71%) when objectively measured. Patients also reported an average time off work of 61 days.
Shepard reported excellent results with a modification of Kutler’s technique in 28 traumatic amputations and 9 reconstructive procedures by dividing the dorsal pedicle and advancing the flap 10 to 14 mm. The nerves, vessels, and subcutaneous tissues are preserved under the palmar skin incision. The dorsal incision is made down to bone and the fibrous septa divided. On the palmar side, the skin is incised only and the flap advanced distally. He suggested that the Kutler technique is most applicable to oblique palmar and transversely oriented amputations.
Given the limited advancement of the Kutler lateral “V-Y” flaps, others have described modifications by either raising the triangular flap on its neurovascular pedicle or extending the flap to the proximal interphalangeal (PIP) joint crease to increase its size and ability to advance distally. The flap could be advanced up to 2 cm, although patients were at risk of cold intolerance (49%), numbness (78%), PIP joint flexion contractures (17%), and DIP joint flexion contractures (22%). These “V-Y” advancement flaps are at risk of necrosis if tension-free closure is not achieved. The tension placed on them at closure could cause a hook nail deformity because it pulls the nail bed palmarly and could also cause diminished sensation due to tension on the digital nerves and its branches. This may be overcome by allowing the proximal wounds to heal by secondary intention or treating them with bilayer matrix wound dressings, thereby avoiding tension of the wounds distally.
Volar Flap Advancement
Moberg is credited with the technique of volar flap advancement for coverage of thumb tip amputations. The flap is a bipedicled, axial-pattern, cutaneous advancement flap. Snow advocated the technique for fingertip amputations when length is to be maintained. Advancing volar skin on its neurovascular pedicle provides the dermis with sensibility without losing length. Arons has modified this with the addition of a terminal dermal graft for padding, and sometimes a skin graft may be added at the base of the digit to gain length.
Regional anesthesia is obtained, the limb is exsanguinated with an Esmarch bandage, and a pneumatic tourniquet is inflated. The distal tip is appropriately débrided, and midaxial incisions just dorsal to the flexion crease at each of the interphalangeal (IP) joints are made on both sides of the digit. The flap is completely separated from the underlying flexor tendon sheath, advanced to the distal tip, and sutured to the nail bed and the adjacent sides of the digit. The tip of the flap may need to be shaped to fit the distal defect. The lateral portions of the skin are sutured in place.
This method is more appropriate for the thumb ( Figure 49.6 ) than for the fingers because of the more mobile skin of the thumb and the decreased likelihood of subsequent flexion contracture. However, in both the thumb and fingers, flap advancement is limited to 1 cm. Reported complications are fixed flexion deformity of the IP joints and skin necrosis on the dorsum of the finger. The studies of Caplan and coworkers, Leffert and associates, and Armenta and Lehrman suggest that the blood supply to the flexor tendon apparatus must be compromised for this flap to be used. Although I do not know of any reports of tendon nutritional complications after the use of this technique, such complications could theoretically be a disadvantage of this method.
Cross-Finger Pedicle Flap
The cross-finger pedicle flap technique, first described by Gurdin and Pangman in 1950, has found acceptance when other techniques for local flap coverage are not possible and in those situations in which it is deemed important to maintain length. Examples of such circumstances are distal amputations of the index finger or thumb and situations in which multiple digits are injured and maintenance of length in the remaining injured tips is critical. The flap, however, is associated with stiffness postoperatively and is considered contraindicated in patients with preexisting arthritis or in patients over the age of 50 years. Paterson noted an increased incidence of stiffness in patients older than 41 years.
The flap provides coverage for an oblique volar defect of the pulp region or for extensive soft tissue loss on the volar fingertip with exposed bone and tendon. The example shown in Figure 49.7 in which the adjacent digit is used as a donor and the flap is laterally based is a common application of this technique. A piece of an Esmarch bandage is used to template the defect and to design the flap. It is important to make a template rather than estimate the flap size. I prefer to cut the template 2 mm larger around its three sides to ensure tension-free insetting of the flap.
Once the template has been made, the donor site is outlined with a marking pen. With careful tissue handling, the flap is reflected with preservation of its venous drainage at the base of the flap. The dissection is carried down to the plane between the paratenon of the extensor mechanism and the subcutaneous fat. Three of the four available margins of the flap are sutured in place on the recipient site. The fourth margin is sewn down at the time of flap detachment and closure. A full-thickness skin graft from the ipsilateral antecubital region or medial forearm is used to cover the defect on the extensor surface of the donor digit. Skin without hair is used because this can be a cosmetic concern, especially if the digits are hairless. To avoid undue tension on the vascular pedicle of the flap, the two fingers may be sewn together or a transdigital Kirschner wire placed. A bulky soft dressing may be reinforced with a plaster splint. At 3 weeks postoperatively, a Penrose drain is placed around the base of the donor digit to assess whether the flap is being perfused from the recipient finger. If so, the flap is detached and inset into the recipient site. Cohen and Cronin modified the technique to include a dorsal sensory branch of the digital nerve that is coapted to the recipient digital nerve at the time of flap division. They reported an average two-point discrimination of 4.8 mm in 88% of the patients in their series.
After detachment of the flap, motion of the digits is encouraged to mobilize all the adjacent joints. Follow-up studies by Sturman and Duran, Kleinert and associates, and Johnson and Iverson have indicated that the return of sensibility to cross-finger flaps as measured by two-point discrimination tests shows excellent reinnervation in the majority of these flaps with progressive improvement occurring with time. Lassner and colleagues reported an average sensibility of 3.6 mm and cold intolerance in 6 of their 15 patients with a bilaterally innervated sensory flap.
Thenar Flap
In 1926, Gatewood described the technique of a thenar flap for coverage of digital tip injuries with exposed bone. This was subsequently expanded on by Flatt in 1957 and modified by Smith and Albin with a technique that they describe as a thenar “H”-flap.
The indications for the random-pattern thenar flap are similar to those for a cross-finger flap, namely, when preservation of length is important and other techniques are not applicable. The flap has been advocated for use only in the index and long fingers and in younger patients without any preexisting arthritis or joint injury. The proposed advantages are (1) better skin color and texture match, (2) abundance of subcutaneous tissues, and (3) return of some sensibility. To avoid permanent joint stiffness or unsightly scarring in the donor area, one must keep in mind the three cardinal technical principles outlined by Melone and colleagues : (1) Design the flap near the metacarpophalangeal (MP) crease of the thumb and avoid the midpalmar area; (2) fully flex the MP joint with whatever amount of flexion is required in the IP joints of the recipient finger; and (3) detach the pedicle 10 to 14 days postoperatively and begin immediate active range-of-motion exercises.
Thenar “H”-Flap.
Figure 49.8 shows the thenar “H”-flap as described by Smith and Albin. The area of contact of the injured digital tip with the thenar eminence is outlined. An “H” is drawn on the skin approximately 20% wider than the defect. The transverse limb of the incision is made at the most distal contact point of the fingertip with the thenar eminence (see Figure 49.8, A ). Square proximal and distal flaps are elevated, including the subcutaneous tissue. The proximal flap is sutured to the fingertip, and the distal flap is sutured to the proximal margin of the defect on the volar side of the injured finger (see Figure 49.8, B ). The proximal flap is advanced distally and the distal flap advanced proximally to close the donor defect. A soft dressing is applied, and 2 weeks later the flap is detached. The fingertip is closed with the proximal flap, and the distal flap is advanced into the thenar defect (see Figure 49.8, C ). This closes the donor site primarily and avoids the potential problem of an unsightly scar in the thenar eminence.
An alternative technique is to elevate a proximally based flap and suture it to the injured tip in a fashion similar to that just described but to use a full-thickness or split-thickness skin graft or Limberg-type flap for the thenar defect when the flap is divided and inset.
Satisfactory outcomes with the thenar flap have been reported in several clinical series. Porter compared the results of 56 pedicle flaps with 44 free grafts. He found sensibility was better in cross-finger and thenar flaps and that these flaps resulted in excellent cosmesis. Porter also concluded that full-thickness grafts were superior to split-thickness skin grafts. In terms of subjective and objective sensibility evaluation, of the five methods evaluated in his study, the results were superior with the thenar and cross-finger flaps.
Island Flaps
A number of elegant and ingeniously conceived island flaps have been described for coverage of fingertip amputations. These consist of flaps raised on their neurovascular pedicle, and advantages include the avoidance of prolonged digital immobilization in an awkward position, single-stage reconstruction permitting early rehabilitation, introduction of an independent blood supply to provide a good soft tissue bed for nerve grafting or repair, satisfactory restoration of a well-padded sensate digital pulp, the potential for a composite tissue transfer, a wide selection of donor sites, and a greater arc of rotation for mobilization of the flap over longer distances. These include homodigital and heterodigital island flaps and can be anterogradely or retrogradely based. However, island flaps are more technically demanding and are associated with complications such as flap failure, joint contracture, and cold intolerance. In addition, they have not proved to be more advantageous than simpler methods of achieving coverage of a fingertip amputation. The use of an island flap may be beneficial in select cases, and the reader is referred to comprehensive review articles to become familiar with the indications and surgical techniques.
Free Flaps
With advances in microsurgery, free tissue transfer has been used to treat complex digital defects, including medial arm free flaps, anterolateral thigh flaps, wraparound toe flaps, and arterialized venous flaps. These can be complicated by their bulky appearance, necessitating revision surgery, donor site morbidity, and unpredictable survival rates. A fasciocutaneous free flap based on the superficial palmar branch of the radial artery has been reported for medium-to-large volar soft tissue defects, including the fingertip region. The use of a free thenar flap has also been reported by Kamei and Sassu and associates. Coverage of complex digital defects using a proximal first dorsal metacarpal artery free flap was recently described in 10 patients. The proximal first dorsal metacarpal artery flap is particularly applicable when the defect is large or when scars or injuries prevent the use of a pedicled homodigital or heterodigital flap. Ulnar artery free flaps have been described for managing complex digital defects because they are thin, have aesthetic and textural characteristics similar to those of the finger, and tend to be free of hair. Given that they require harvesting of a major artery, ulnar artery perforator free flaps have been developed to treat such defects. These can be either proximally or distally based. Zheng and colleagues described the use of a distal ulnar artery perforator bilobed free flap in the treatment of 15 patients with complex digital defects. Citing the advantages of having a cosmetic appearance similar to that of digital skin, the presence of the donor and recipient sites within the same surgical field, preservation of the main trunk of the ulnar artery, having a size similar to that of the proper digital artery, containing both the accompanying and superficial veins, and allowing sensation via the medial cutaneous nerve of the forearm or dorsal sensory branch of the ulnar nerve, the authors reported satisfactory outcomes in 14 of 15 patients (1 patient had partial flap necrosis) with good digit range of motion and two-point discrimination ranging from 6 to 11 mm.
Author’s Preferred Method of Treatment: Digital Tip Amputation
I prefer to treat all digital tip injuries without exposed bone nonoperatively, with dressing changes or ultrasonic MIST therapy to allow healing by secondary intention. Educating the patient and the family with photographs from previous cases has proven to be invaluable. The analogy that the injury looks “like a dog’s dinner” and that it will heal, with pictures from similar case examples, allows one to gain the trust of the patient and help the patient engage with therapy.
In single-digit injuries with a small protruding portion of the distal phalanx, I will trim the bone back and allow healing by secondary intention. For larger defects with more exposed bone, I prefer the “V-Y” advancement flap for dorsal oblique or transversely oriented fingertip amputations. For volar oblique wounds, I use bilayer matrix wound dressings followed by a skin graft when appropriate. I tend not to favor the thenar flap for concern of developing IP joint stiffness but may consider it in young patients with index or long fingertip amputations. If the defect is large, I use a cross-finger flap. If the defect also involves a large portion of the volar tissues, I use a neurovascular island flap, although I have become more and more impressed with the results obtained with bilayer matrix wound dressings and have been increasing their indications in my practice.
Amputations from the Distal Interphalangeal to the Metacarpophalangeal Joint (Excluding the Thumb)
Distal Interphalangeal Joint Disarticulation
My preferred method of management for an amputation through the DIP joint or just distal with loss of flexor digitorum profundus (FDP) function is skeletal shortening and primary closure. I preserve the FDP attachment when possible to maintain some length, IP joint flexion, and pinch stability ( Figure 49.9 ). If the insertion of the FDP is not salvageable, I pull the tendon as far distal as possible and transect it under tension. Whitaker and colleagues presented experimental and clinical data suggesting that there was less inflammation if the articular surface of the middle phalanx was preserved. However, I believe that the shape and contour of the amputation stump should be fashioned to resemble the normal distal phalangeal tuft. This is accomplished by rongeuring off the volar and lateral condylar prominences. The digital nerves should be dissected and cut under tension to allow them to retract away from the cutaneous scar into an area where the inevitable neuromas will not become symptomatic. The flexor and extensor tendons should be inspected and their cleanliness established; they should not be sutured to each other. This inevitably limits the excursion of both and compromise function of the remaining digits. Wang and associates reported on the outcomes of revision amputation at or distal to the DIP joint and noted that the average arc of motion of the PIP joint was 94 degrees; 24% of patients experienced cold intolerance; most patients had normal sensibility with a mean two-point discrimination of 5.6 mm; and the return to work averaged 7 weeks after surgery.
Complications of Digital Amputation: The Lumbrical-Plus Finger
Distal release of the FDP tendon to the index finger may lead to a “lumbrical-plus” deformity. As the independent FDP and its lumbrical move proximally, tension increases in the lumbrical tendon and its contribution to the intrinsic extensor of the PIP joint. As active flexion of the digit is attempted, further proximal migration of the lumbrical may put sufficient tension on this lateral band to cause paradoxic extension of the PIP joint. Sectioning the lumbrical tendon allows the superficialis to regain control of the PIP joint and may alleviate the problem. In my experience, this rarely occurs, and sectioning of the lumbrical is unnecessary at the time of the amputation.
Amputation Through the Middle Phalanx
If amputation has occurred proximal to the DIP joint of the index finger, most patients will transfer pinching and picking up of small objects to the tip of the long finger ( Figure 49.10 ). Therefore, efforts to preserve index finger length by flap coverage may be necessary. Preserving length in other digits may also be important in certain occupations such as a professional musician or one who uses a computer keyboard and mouse. For injuries in which preserving length is not feasible, the bone should be shortened sufficiently to allow primary coverage with available skin without tension ( Figure 49.11 ). The flexor digitorum superficialis (FDS) insertion should be preserved because the middle phalangeal segment will be able to participate effectively in grasping activities; PIP flexion is always limited, however, if the middle phalanx stump is short. If amputation has occurred proximal to the insertion of the superficialis or if the tendon has been transected, there will be no active flexion of the remaining middle phalanx; therefore, preservation of the middle phalanx is more of a cosmetic issue and less of a functional consideration ( Figure 49.12 ).
The amputation is designed as a “fish-mouth” incision with equal palmar and dorsal skin flaps ( Figure 49.13 ). Alternatively, the incision can be fashioned with a larger palmar skin flap to ensure that the thicker palmar skin covers the tip surface. Regional or digital anesthesia can be used for this procedure. Limb exsanguination is performed by arm elevation and compression of the brachial artery for cases of infection or tumor. Otherwise, the arm is elevated and exsanguinated using an Esmarch bandage. The skin is incised and the extensor tendon cut. On the palmar surface, the neurovascular bundles are identified and the digital vessels isolated and cauterized. The digital nerves are dissected proximally and cut under tension so they retract proximally. The FDP tendon is cut under tension. The insertion of the FDS tendon is protected as much as possible and the osteotomy of the middle phalanx planned a few millimeters proximal to the level of the skin incision to ensure tension-free closure. The phalanx is cut using a reciprocating saw and the ends are smoothed with a rasp. If a disarticulation is to be performed, the articular cartilage is left intact but the volar and lateral condyles are trimmed with a rongeur to decrease stump protuberance. The tourniquet is deflated, hemostasis is obtained, and the wounds are closed with a 4-0 nonabsorbable suture. A soft dressing is applied and range-of-motion exercises are encouraged. Sutures are removed at 2 weeks or once the wounds have healed. Edema control and desensitization exercises are initiated.
Amputations Through the Proximal Interphalangeal Joint
Amputations through the PIP joint should be carried out in a manner similar to those through the DIP joint, with denuding of articular cartilage, shaping of the condyles of the proximal phalanx, and coverage with local skin.
Amputation Through the Proximal Phalanx
If an amputation has occurred proximal to the PIP joint, the remaining proximal segment is under motor control of the intrinsic muscles and the extensor digitorum communis. This provides active MP joint flexion of approximately 45 degrees. The remaining segment will participate in gripping and help keep small objects in the palm. To improve flexion at the MP joint, tenodesis of the FDS tendon to the end of the proximal phalanx can be performed. Kirschner wire holes are made through the distal end of the proximal phalanx and the FDS tendon is sutured at its resting length to the phalanx, which provides almost 90 degrees of flexion with grasp ( Figures 49.14 and 49.15 ).
If the amputation has occurred near or at the MP joint level, particularly in the long and ring fingers, functional problems such as dropping small objects through the defect will result, and further consideration of prosthetic replacement or a proximal ray amputation should be contemplated. If the amputation involves the index finger, immediate ray amputation should be considered.
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Amputations through the DIP joint are managed by skeletal shortening and primary closure.
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If the FDP attachment and, thus, DIP joint flexion are intact, length should be maintained with flap coverage to preserve joint motion and stability.
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In amputations through the middle phalanx, bone should be shortened to allow primary coverage by available skin without tension. If possible, the amputation level should be distal to the FDS insertion.
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Amputations through the PIP joint are managed like those through the DIP joint.
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If amputation through the proximal phalanx is near the PIP joint, some useful gripping function is preserved and can be enhanced with FDS tenodesis.
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If amputation is near or at the MP joint, ray amputation should be considered.
Ray Amputations
A ray amputation involves excision of a digit from its metacarpal base. Indications include trauma, tumor resection, infection, failed replantation, debilitating Dupuytren disease, and macrodactyly. When considering a ray amputation, it is important to think about its effects on overall hand function because the amputation will affect the three functional units—namely, (1) an opposable thumb, (2) the index and long fingers for pinch, and (3) the ring and small fingers for grip. It can narrow the palm span by 10%, with a resultant decrease in grip strength. However, the narrower palm must be weighed against other impairments related to the space created by the missing digit, especially for the central digits, because small objects may fall through this area. Ray amputation may be indicated at the time of initial trauma, but in most instances, it is performed as an elective procedure secondary to functional impairment or unremitting pain. In most injuries, the principle of saving all viable tissue should be followed. Tissue that may appear at first glance to be of little functional benefit may serve as a good source of material for subsequent reconstruction (e.g., bone graft).
Peimer and colleagues conducted a retrospective review of 12 patients who underwent primary ray amputations (within 2 weeks) and 13 patients who had secondary ray amputations for either traumatic or oncologic reasons. They noted that patients who underwent primary ray resection had better strength and dexterity and had to take less time off work. On average, patients lost 28% of grip strength, 26% of opposition, and 13% of key pinch strength. The vast majority of patients, excluding those involved in workers compensation or litigation cases, were satisfied with the functional outcome, with most returning to the preinjury occupation. Melikyan and colleagues reported on 20 patients at an average of 32 months following surgery. Grip strength decreased by 27% and three-point pinch by 22%. Patients who had an amputation of border digits recovered better than those who had amputation of the central digits, with the latter group having impaired manual dexterity.
Index Finger Ray Amputation
Murray and colleagues reviewed 41 patients who underwent index finger transmetacarpal amputation (13 patients at the level of and 28 patients proximal to the metacarpal head). They reported a 20% reduction in power grip, key pinch, and supination strength. Pronation strength, which is a measure of grasp stability, decreased by 50% owing to the narrowing of the palm. With loss of the index finger, the pronosupination fulcrum is decreased by 25%, resulting in a loss of stability and a mechanical disadvantage for forearm rotation ( Figure 49.16 ). There was no significant difference in strength between those who had proximal or distal amputations. Patients noted that the overall hand function had improved, despite the loss in strength, because of the ability to maintain thumb prehension. Cold intolerance was the most common persistent symptom (35 of 41 patients). Fifty-nine percent of patients had suboptimal results owing to hyperesthesia in the thumb/long finger web space. This was secondary to excessive mobilization of the index finger radial digital nerve during the amputation process and interfered with hand function in 37% of patients. Fisher and Goldner reported a similar complication in five patients; it appeared 6 to 8 weeks after surgery. Although this problem may resolve with secondary surgery, the symptoms may recur over time. In the series of Murray and associates, 34 patients underwent elective ray amputations. Twenty-one complained of pain in the stump before the transmetacarpal amputation, and only 3 experienced complete relief after the procedure. This information is important when advising a patient preoperatively about the possibility of persistent postoperative neuroma-like symptoms . Ay and Akinci described a technique of primary transposition of the index finger digital nerves into the interossei to decrease neuroma formation. After amputation of the digit, the radial and ulnar digital nerves are mobilized in a proximal direction and inserted within the interossei of the long finger.
In an effort to restore strength to the long finger, several tendon transfers have been described, including transfer of the first dorsal interosseous muscle to the second dorsal interosseous tendon or extensor hood, the extensor indicis proprius to the long finger extensor, or the FDS to the proximal phalanx of the long finger. Of the more commonly performed transfers, Murray and associates found no differences in key pinch strength in patients who had or had not undergone transfer of the first to the second dorsal interosseous tendon. In 11 of 28 cases in which the second dorsal interosseous tendon was augmented by transfer of either the first dorsal interosseous tendon or one of the long flexor tendons of the index finger, there was an intrinsic-plus deformity evident on clinical examination. From these data it would appear that procedures designed to augment the second dorsal interosseous tendon are unnecessary and may lead to additional complications.
Germann and colleagues reported on 120 patients with ray amputations (42 of the index finger). The majority of patients noted minimal functional deficits in performing activities of daily living. There was no significant loss of strength compared with patients who had undergone an amputation through the middle phalanx with respect to tip, key, and palmar pinch and sustained grip. Unlike those who had undergone digital amputation, 90% of patients with a ray amputation were happy with the cosmetic appearance. Similar results were reported by Melikyan and associates in an evaluation of ray amputations. Eight of the 20 patients underwent index finger ray amputation. Grip strength was decreased by a mean of 19% compared with the contralateral hand. Interestingly, 6 of 8 patients learned to transfer manual dexterity precision skills (commonly performed between the thumb and index finger) to the long finger without difficulty, presumably because of the unrestricted first web space. Many cases of ray amputation are performed following trauma. Puhaindran and coworkers reported on the outcomes of single-ray amputation (7 of the index finger, 5 of the long finger, 6 of the ring finger, and 7 of the small finger) for tumors of the hand that included soft tissue malignant tumors, metastases, giant cell tumors of bone, and primary bone sarcomas. Ten patients underwent postoperative radiation treatment (2 for positive margins and 8 for close margins). None of the patients had local recurrences. Patients who received preoperative radiotherapy had a decrease in functional outcomes and grip strength that averaged 66% compared with the contralateral hand.
Author’s Preferred Method of Treatment: Index Finger Ray Amputation
For trauma cases, transmetacarpal amputation is not performed in the acute setting unless there is injury proximal to the MP joint. In cases of multiple-digit injuries, it is especially important to preserve as much finger length as possible. For ray amputation, regional anesthesia is preferred. For cases of infection or tumor, limb exsanguination is performed by arm elevation and compression of the brachial artery. Otherwise, the arm is elevated and exsanguinated using an Esmarch bandage. A proximally based “V” incision is fashioned on the volar surface at the midproximal phalangeal level of the index finger. Dorsally, this is joined by a “Y”-shaped incision with proximal extension over the index metacarpal ( Figure 49.17, A ). The longitudinal dorsal incision is made through the subcutaneous tissue, and the veins are ligated as necessary. If indicated, dorsal sensory branches of the superficial radial nerve should be divided under tension to allow proximal retraction. The extensor digitorum communis and extensor indicis proprius tendons are divided at the level of the second metacarpal base and reflected distally to expose the underlying periosteum. The dorsal periosteum is sharply incised, and a subperiosteal sleeve is raised. The index finger metacarpal is transected via a reciprocating saw distal to the insertion of the extensor carpi radialis longus tendon (maintaining wrist strength), with care taken to protect the underlying radial artery as it passes beneath the base of the metacarpal (see Figure 49.17, B ). A rasp is used to address any rough edges of the transected metacarpal base. Dissection is carried around the distal circular portion of the incision. The first dorsal interosseous tendon and lumbrical muscle to the radial side of the index finger are divided. One next proceeds around the palmar aspect of the finger, and the neurovascular bundles to the index finger are identified. Care must be taken to identify and protect the radial digital nerve to the long finger and its accompanying digital artery. The vessels to the index finger are ligated and the digital nerves dissected distally into the middle phalangeal segment and divided. The flexor tendons are transected under tension to promote retraction into the palm. The tendon of the first palmar interosseous tendon is also divided.
The volar plate, deep transverse intermetacarpal ligament (DTIL), and proximal portion of the flexor tendon sheath are sharply incised, permitting delivery of the amputated digit. The distal end of the digital nerves that have intentionally been transected in the finger are now carefully dissected proximally, with their connections with the palmar skin left undisturbed (see Figure 49.17, C ). The distal ends are transposed proximally into the interosseous space between the first and second dorsal interossei to provide protection from external compression (see Figure 49.17, D ). Alternatively, the nerves may be coapted. The tourniquet is deflated, hemostasis is obtained, and the periosteal sleeve is closed. The skin flaps are trimmed, inset, and closed with interrupted sutures. A well-padded soft dressing is applied, and early motion is encouraged. Strengthening is started at 6 weeks following operation. Patients should be followed to ensure an uneventful recovery because complications such as neuroma formation and carpal tunnel syndrome may occur. The latter may occur as a result of proximal migration of the transected flexor tendons into the carpal canal.
Long Finger Ray Amputation
Given its central location, the long finger plays an important role in hand function, especially in lateral pinch, chuck pinch, and power grip. Any loss of length distal to the PIP joint can lead to small objects falling between the gap of the index finger and ring finger ( Figure 49.18 ) and a loss of three-point chuck pinch. Angular deformity of the index finger can occur when the amputation is at the level of the MP joint. Key pinch strength is diminished because the origin of the adductor pollicis muscle is removed from the long finger metacarpal. One of the main complications following central ray deletion is scissoring of the adjacent index and ring fingers due to instability of the DTIL and altered intrinsic muscle function. Given this, two techniques of long finger ray amputation have been popularized, namely, repair or reconstruction of the DTIL and ray transposition.
Long Finger Ray Amputation Without Transposition
Melikyan and colleagues reported on the outcomes of patients who underwent central ray amputation compared with those who underwent border digit ray amputation. Amputations were performed through the base of the metacarpal, and the DTIL was closed for central deletion cases. Compared with patients who underwent border digit deletion, those who underwent long finger ray amputation had weaker three-point pinch, decreased manual dexterity, and weakness in torque power and work output of up to 38% compared with the contralateral hand. The authors did not find any cases of gapping or scissoring by primarily repairing the DTIL ( Figure 49.19 ). One of the concerns with imbrication of the DTIL when the metacarpal base of the long finger is left in situ is the scissoring that may develop as the metacarpal heads of the index finger and ring finger are drawn together. This was highlighted by Steichen and Idler, who stated that the procedure may be better suited for ring finger ray amputation because in the ring finger, the metacarpal is thinner and gap closure is more readily achieved due to the mobility of the fifth carpometacarpal (CMC) joint; in the long finger, the metacarpal is wider and the index finger CMC joint stiffer. Nonetheless, in their report of 13 patients (4 of whom had long finger surgery and 9 of whom had ring finger surgery), satisfactory functional and cosmetic results were noted in all but 1 patient, who complained of continued palmar tenderness and narrowing of the palm. For cases in which the DTIL is absent or deficient, Gong and coworkers described a technique of reconstructing the dorsal transverse intermetacarpal ligament using a free tendon graft. Following metacarpal base osteotomy, a free tendon graft (either a graft from the amputated digit or an autograft) is looped around the index and ring finger metacarpal necks and sutured to itself and to the adjacent periosteum ( Figure 49.20 ). An alternative method of fixation would be to use biotenodesis screws within the index finger and ring finger metacarpal necks.
To draw the index and ring fingers closer together, Iselin and Peze described a technique whereby a closing wedge osteotomy of the capitate (distally based wedge with apex proximal) is performed after long finger ray amputation. The operation was performed in 12 patients, and the authors reported satisfactory closure of the gap between the index finger and ring finger with soft tissue repair; patients were satisfied with the functional and aesthetic results. Alternatively, Lyall and Elliot described a technique whereby the entire middle finger ray is amputated at the CMC joint. Care must be taken to protect the underlying motor branch of the ulnar nerve. Subperiosteal dissection of the extensor carpi radialis brevis from the dorsal aspect of the long finger metacarpal base is necessary to preserve its function. Reconstruction of the hand involves closing the gap between the index finger and ring finger metacarpals while avoiding angulation and malrotation. From proximal to distal, sutures are placed between the periosteum/muscles of the index finger and ring finger metacarpals, followed by their respective sagittal bands and DTIL (having excised the palmar plate of the long finger MP joint, which can act as a barrier to preventing closure of the dead space). Dorsal skin excision or dermadesis helps to further support the reconstruction. A palmar “V” flap of excess skin is excised.
Author’s Preferred Method of Treatment: Long Finger Ray Amputation Without Ray Transposition
After satisfactory regional or general anesthesia, the limb is exsanguinated and a tourniquet is applied. A dorsal incision is made and extended along the shaft of the long finger ray ( Figure 49.21 ). The distal ends of the incision are carried over the proximal phalangeal skin to preserve sufficient skin for closure of the commissure between the index and ring fingers. This technical point is important when performing ray amputations of the middle two rays to preserve skin and prevent iatrogenic web contracture. Alternatively, a web-saving incision that avoids placing the scar in the new web space can be used ( Figure 49.22 ).
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