Recently I received the following e-mail:
"I came across your blog about fingertip injuries. When I was 4 years old I slammed a door on my pinky finger. The tip came off leaving me with what they call a hook nail. I have been trying to research any procedures that may improve the appearance of my finger. Do you have any suggestions or info on any procedures."
Secondary reconstruction is always less effective than "doing it right" at the time acute care is given to a nail bed injury. The appearance and shape of the nail improves during the first year after the injury so no attempts at reconstruction of the nail bed should be made until after the first year. You may want to refer back to my post on fingernail anatomy and fingertip injuries.
Typical nail deformities that require reconstruction include:
- Non-adherent nails -- is the most common deformity of the nail plate after injury. It occurs due to scar tissue in the sterile matrix which prevents attachment of the nail plate to the nail bed. The non-adherent nail "sits" upwardly deviated from the nail bed. The lack of nail plate adherence becomes more of a functional than a cosmetic problem when more than one third of the distal nail is non-adherent. This allows it to catch on clothing and other articles putting the nail bed at risk for further injury. Dirt and other debris gather underneath the non-adherent nail and cause further irritation. Nail adherence on more than two thirds of the nail bed rarely results in a functional impairment.
- Irregular contours -- The linear ridging deformity of the nail following a trauma is most often associated with an underlying bone or soft tissue abnormality. The ridging usually is more of a cosmetic problem more than a functional one.
- Hook nail -- is usually the result of a fingertip amputation, with partial or complete loss of the supporting tuft of the distal phalanx (bone) and a loss of the distal nail bed and fingertip soft tissue. The regenerating nail plate follows the contour of the repaired fingertip amputation, angling in a dorsal (top) to volar (palm) direction. The hook-nail deformity is more than a cosmetic disfigurement to the patient's finger. The tip of the finger is often tender and chronically irritated, and sensibility may be impaired. The patient may also have difficulty grasping fine objects. Occasionally, the nail may catch on clothing or other utensils and become a constant source of trauma.
- Pincer nail deformity -- represents a loss of the normal convex shape of the nail plate. The lateral edges of the nail plate have a marked convexity, turning acutely volarly (towards the palm) and taking on the characteristic shape of an omega sign when viewed head on at the distal phalanx. The exact etiology of this deformity is somewhat obscure, but a loss of the lateral integrity of the distal phalanx may occur, allowing this greater curvature of the nail plate. Paronychial infections may be more frequent with this type of nail irregularity.
- Loss of the eponychium with synechiae -- Burns are the most common cause of loss of the eponychium. Other causes include friction avulsions, crush injuries, and complex lacerations. The eponychium contributes to the epidermoid keratinization of the nail, providing the characteristic sheen on a dorsal nail plate. So loss of the eponychium can result in an unsightly nail or notched deformity which can be a source of tenderness for the patient.
- Treatment involves trimming the nail back to normal sterile matrix. The scar in the nail bed is then excised and the defect is closed primarily or with split matrix grafts. Primary closure may be obtained with minimal nail bed undermining if the defect is less than 1-2 mm. The nail plate should adhere to the graft.
- If the cause of non-adherence is due to hyperkeratosis of the nail bed, then the nail is removed. Then the hyperkeratosis is removed by scraping the sterile matrix with the edge of the scalpel blade down to the level of the normal nail bed. The nail either grows out completely or partially adheres to the nail bed. The procedure may be repeated if complete adherence is not achieved.
Split Nail Deformities
- Treatment is determined by the underlying problem.
- Longitudinal scars on the sterile matrix of the nail bed can usually be treated by excision and primary closure. Small Z-plasties (2 mm in length) can be used to alter the direction of the scar. Larger scars will require a split-thickness nail bed graft following excision. Loss of the central portion of the germinal matrix requires grafting with a full-thickness germinal matrix graft from the toe.
- Adhesions within the eponychial fold are treated by removing the nail plate and dividing the synechia transversely. Upward traction on the open portion of the nail fold should allow visualization to perform the transverse incision. Any scar tissue of the germinal matrix and dorsal roof of the eponychium must be excised. A germinal matrix graft is then applied. Simple excision of the germinal matrix scar with primary approximation is less effective.
- Reconstruction of the dorsal roof of the eponychium help restores the normal sheen to the regenerating nail. A silicone sheet (acts as a splint for the graft) should be placed in the nail fold to maintain the integrity of the eponychial fold until the grafts have "taken".
Linear Ridging Deformity
- As with the other deformities, the nail plate must be removed and the sterile matrix visualized. An incision is made over the ridge in a longitudinal fashion. The sterile nail bed is elevated from side to side (radially and ulnarly) to expose the underlying tissue. Scar tissue, foreign bodies, or bony exostosis must be removed. The nail bed is redraped and sutured with 7-0 chromic sutures. Any excessive scarring of the sterile matrix should be excised and replaced with a split-thickness nail bed graft. The nail plate or silicone sheeting is then placed over the repair and under the eponychial fold.
Hook Nail Deformity
- Can be somewhat difficult because of the loss of bony and soft tissue support. Secondary reconstruction is centered on recreating the initial defect, then restoring the bony and/or soft tissue support.
- Soft tissue support on the volar (palm-side) aspect of the finger can be accomplished with V-Y Atasoy/Kleinert flaps, lateral Kutler flaps, a cross-finger flap, or a thenar crease flap.
- Split nail bed grafts (distal edge) are applied directly to the volar flaps, and the proximal edge is sutured to the native nail bed.
- Restoring the bony support is less predictable. Distraction osteogenesis, bone grafting, and step cutting in the distal phalanx are likely to lead to a high rate of resorption.
- Microvascular composite flaps of nail bed, bone, and soft tissue from the toe have been described with excellent results. A high level of microsurgical expertise is essential and the patient must be willing to sacrifice a toe for this procedure. This may be hard to justify as the local flaps mentioned above are easily and more reliably performed.
- Revision amputation is an alternative to reconstructing a problematic hook-nail deformity.
Pincer Nail Deformity
- Is corrected by using dermal grafts to "build up" the sides of the nail bed. This is done by first removing the nail plate. Then an incision is made in an oblique fashion in the pulp of the distal fingertip just distal to the end of the lateral nail folds. The nail bed is elevated off the distal phalanx by passing a Freer periosteal elevator into the wound gently pushing proximally. This will create a tunnel that is 2-3 mm wide and extends the full distance of the nail bed, including the germinal matrix. Care must be taken not to damage or buttonhole the overlying nail bed.
- Nylon sutures (5-0) are then placed through the dorsal skin into the tunnel created between the distal phalanx and the lateral bed. The suture is carried out of the wound to capture the proximal end of a dermal graft. The suture is passed back through the tunnel and out the dorsal skin, exiting near the entrance of the previous suture. The dermal graft is advanced through the tunnel by pulling on the sutures. The suture is tied, securing the dermal graft in the tunnel. The excess length of the dermal graft is excised, and the wound is closed with a single nylon suture. Both sides (medial and lateral) of the nail plate are done in the same way.
- A silastic sheet (the old nail won't work here--wrong shape) is introduced into the eponychial fold. The sheeting is removed in approximately 10 days. The procedure has had excellent results in restoring the nature contours of the nail plate.
Loss of the eponychium with synechiae
- Entirely removing the nail plate is often necessary to see the remaining edges of the proximal nail fold. As with the other deformities, any scar tissue of the nail bed, matrix, etc must be removed.
- Composite grafts can be obtained from the large or second toe. These composite grafts include the dorsal roof of the eponychial fold as well as the dorsal skin.
- The composite graft is sutured in place with a 7-0 chromic and 6-0 nylon sutures, and the nail plate is replaced. The surgical site is then covered with sterile gauze and dressed as described previously.
- The survival of the grafts can be precarious. The postoperative immobilization must be meticulous.
- Occasionally enough skin is available on the dorsum (top) of the finger to rotate or transpose as local flaps to the eponychium. A split sterile matrix graft can then be sutured to the undersurface of the flap to restore the dorsal roof bed. The donor site of the flap is closed primarily or covered with a split-thickness skin graft.
COMPLICATIONS / OUTCOMES
The results of the initial repair are far better than reconstructive attempts.
Infections to the nail bed following repair are uncommon.
Split-thickness sterile matrix grafts are required for areas of nail bed loss. The excellent results obtained from split grafting the nail bed defects have made this procedure common practice for most hand surgeons. The donor site heals without difficulty with most authors reporting no residual deformities secondary to graft harvesting. Orientation of the split graft on the recipient bed does not affect adherence or nail plate morphology. Though most will have good results, some patients may have some nail plate irregularity with linear ridging or distal nonadherence (usually at the site of the initial avulsion and not at the site of donor harvesting).
Germinal matrix defects must be treated with a full-thickness germinal matrix graft. The type of material (silicone sheet, nail plate, sterile petroleum jelly-impregnated gauze) placed in the eponychial fold does not appear to influence the final outcome and appearance of the regenerating nail plate.
It can not be said enough:
Careful initial repair has a better outcome than secondary reconstructive surgery.
Nail Pathology; Michael Neumeister MD and Dimitrios Danikas MD; eMedicine Article, October 27, 2004
The Perionychium; Zook EG, Brown RE; In: Green DP, ed. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone; 1999.
Nailfold Reconstruction for Correction of Burn Fingernail Deformity; Plastic & Reconstructive Surgery, 117(7):2303-2308, June 2006; Donelan, Matthias B. M.D.; Garcia, Jesus A. M.D., Ph.D.
Nail Transfer: Evolution of the Reconstructive Procedure; Plastic & Reconstructive Surgery. 100(4) Supplement 1:907-913, September 1997; Endo, Takashi M.D.; Nakayama, Yoshio M.D.; Soeda, Shougo M.D.
Nail Lengthening and Fingertip Amputations; Plastic & Reconstructive Surgery. 112(5):1287-1294, October 2003; Adani, Roberto M.D.; Marcoccio, Ignazio M.D.; Tarallo, Luigi M.D.
Nail Regeneration by Elongation of the Partially Destroyed Nail Bed; Plastic & Reconstructive Surgery. 111(1):167-172, January 2003; Lemperle, Gottfried M.D., Ph.D.; Schwarz, Martin M.D.; Lemperle, Stefan M. M.D.
Nail Surgery; Neh Onumah MD and Richard Scher MD; eMedicine Article, September 18, 2006