When surgery involves the nail matrix, there are three primary approaches, including (1) a reduction in its width or (2) its length for removal of tumors, for instance, by using a cold steel procedure or (3) a 2-to 3-mm punch biopsy. In contrast to these three procedures, complete matricectomy, that is, ablation of the nail-forming tissue, is rarely performed because the nail is permanently lost (eFig. 245-12.1).
Matricectomy. A. Area of excision.B. Remaining defect.
After reduction of the nail matrix width, one is left with a narrower nail and after reduction of the length, with a diminution in the thickness of the nail. Reduction of the matrix width is a useful and/or necessary procedure in the following major circumstances:
- Need for lateral-longitudinal biopsy
- Lateral nail splitting
- Benign or malignant tumor in the lateral third of the nail apparatus
- Longitudinal melanonychia in a lateral location
- Ingrown nail
- Racquet nail
Reduction of the matrix length is necessary only in limited cases: to obtain a transverse elliptical biopsy specimen, to treat tumors that are 3 mm wide or larger, and to thin thick nails in patients with dystrophic congenital and/or hereditary disorders.2
Biopsy of the nail matrix is performed to determine the histopathologic features of a lesion or to clarify an uncertain clinical diagnosis.
A 3-mm punch biopsy may be performed through the nail plate into the matrix. Three millimeters is the maximum size that does not produce serious dystrophy, although even biopsies of this size can cause such effects if carried out in the most proximal portion of the nail matrix. When a punch biopsy is used to sample longitudinal melanonychia of less than 3 mm in width, the circumferential incision is made around the origin of the band, through the nail plate (Fig. 245-7A). This area may be distal enough to be reached by pushing back the cuticle (Fig. 245-7B), but if it is more proximal, the proximal nail fold may have to be reflected using a posterolateral incision. The next step is to remove the proximal third of the nail plate (see Fig. 245-7B and C), while leaving the cylinder of tissue containing the origin of the longitudinal melanonychia still in place. This technique allows the surgeon to inspect the surrounding nail matrix and bed with a magnifying lens to determine whether pigment extends around the punch incision (see Fig. 245-7C and D) and facilitates the removal of the cylinder of biopsy tissue with a Gradle scissors.
A. Punch biopsy of longitudinal melanonychia of less 3 mm in width. B–D. Removal of the base of the nail plate (B) to allow easy removal of the biopsied cylinder of matrix tissue (C) and pigment left distally (D).
For lateral longitudinal biopsy (Fig. 245-8), an elliptical incision may be made on either side of the nail plate and proximal nail fold. For the most part, the incisions parallel the lateral edge of the nail plate. Beginning in the lateral nail groove, the incisions should include a 3- to 4-mm nail segment reaching to the bone. This ensures that a full-thickness fragment of the matrix with its lateral horn is obtained. Slightly curved iris scissors are useful for separating the tissue from the bone. Starting at the tip of the digit, one proceeds proximally while maintaining contact with the bony phalanx. Lateral longitudinal biopsy is the advised procedure when longitudinal melanonychia3 is located in the lateral part of the nail plate.
Lateral longitudinal biopsy of longitudinal melanonychia located within the lateral third of the nail plate.
For transverse biopsy (Fig. 245-9), two small oblique incisions are made on each side of the proximal nail fold. The fold is then reflected to expose the matrix area. The proximal third of the nail plate is avulsed. Then, the lesion is removed by excising an elliptical or crescent-shaped wedge of tissue with the convex portion of the crescent paralleling the anterior border of the lunula. When longitudinal melanonychia lies within the midportion of the nail plate, the potential for postoperative dystrophy is great, and selection of the optimal biopsy method is difficult (eFig. 245-10.1) (Haneke's releasing flap technique derived from Schernberg's releasing flat method). It is important to establish the matrix origin (proximal or distal) of longitudinal melanonychia preoperatively, because the more proximal the origin, the greater the risk of nail dystrophy.3 The origin of pigmentation may be determined by microscopic examination of Fontana-Masson–stained clippings from the free edge of the nail.
Transverse biopsy of the nail matrix.
Haneke's releasing flap technique for longitudinal melanonychia within the midportion of the nail plate.
Tangential matrix biopsy (Fig. 245-10) for longitudinal melanonychia is a new technique devised by E. Haneke. Cutting, then reclining the proximal portion of the nail plate (1), after reflecting the proximal nail fold (2), the pigmented lesion is exposed. An incision is made around the lesion, followed by its tangential removal. Finally the proximal nail plate is replaced and the oblique incisions of the proximal nail fold are maintained by micropore. This technique is claimed to give the best cosmetic results.
Reflected proximal nail fold and removal of the proximal portion of the nail plate exposing the pigmented lesion. Around the latter is made an incision followed by its tangential removal Haneke's matrix tangential biopsy technique.
The common causes of split-nail deformity include trauma, surgery, lichen planus, and tumors. Split-nail deformity may occur in either the lateral or the medial region. The appropriate surgical technique varies accordingly.
If the split is located within the lateral third of either portion of the nail, especially when it is close to the lateral margin, the best method is the technique recommended for lateral longitudinal nail biopsy, that is, the removal of the lateral portion of the nail with the defect. If the split is located in the middle region of the nail and involves its whole length, the proximal nail fold is carefully freed from the underlying nail plate, obliquely incised at both sides, and reflected to expose the whole matrix area (Fig. 245-11). The nail plate bordering the split is cautiously cut as a rectangular block approximately 1 mm wider than the scar that has to be excised. The nail bed and matrix of the defective tissue are dissected from the bone to allow an exact approximation of the remaining bed and matrix, which are sutured with 6-0 monofilament absorbable sutures. To prevent the sutures from tearing the tissue, 3-0 sutures are put through the nail plate. When these threads are knotted firmly, the matrix and nail bed are further approximated, which relaxes the 6-0 sutures.
Treatment of split nail in the middle region of the nail plate.
If the scar is too wide to allow primary closure of the defect, relaxing longitudinal incisions along the lateral nail grooves down to the bone usually permit suturing. An alternative approach is the formation of a Schernberg nail bed–matrix flap with an L-shaped incision of the lateral aspect of the finger (eFig. 245-11.1).
Schernberg's releasing flap method.
Nail Ablation and Isolated Matricectomy
Nail ablation (eFig. 245-12.1A) is the definitive removal of the entire nail organ and matricectomy (eFig. 245-12.1B), the complete extirpation of the nail matrix, which results in permanent nail loss. The principle of nail ablation is the complete removal of the nail unit with hyponychium, nail bed, matrix, and lateral and proximal nail folds. Except for treatment of malignant tumors of the nail apparatus, nail ablation is rarely indicated. It may be necessary in the case of an excessively painful nail treated several times without success, but this should be an exception. Scalpel excision is strongly advocated whenever the surgical specimen needs histopathologic examination. If periungual pigmentation is associated with longitudinal melanonychia or if the latter is wider than 6 mm or the full thickness of the nail is pigmented, a large portion of the matrix would necessarily be involved. Under these circumstances, the underlying disease process is unlikely to be benign. The entire portion of the involved nail apparatus has to be excised en bloc.
The defect from nail ablation (see Fig. 245-12B) may be covered with a free graft (split-thickness, full-thickness, reversed dermal graft), which usually takes on the bone in this particular location. A cross-finger flap is a very useful alternative to a free graft. The use of the skin from the intermediate phalanx of a neighboring finger is more convenient for the patient than skin from the thenar area of the palm.
Nail ablation. A. Area of excision. B. Remaining defect.
If only permanent nail matrix removal is necessary, the procedure is less extensive.
In cases in which pathologic examination of the removed tissue is unnecessary, phenol cautery, rather than scalpel excision, is the preferred technique for matricectomy. Most patients return to normal ambulation and activity as early as 1 day after the operation.
Nail-bed surgery is performed for biopsy, removal of tumors, and treatment of nail dystrophies such as onychogryphosis.
Biopsy (Fig. 245-13) may be useful in any pathologic condition involving the nail bed.
Nail bed biopsy. A. Punch biopsy. B. Fusiform biopsy.
Punch biopsy is done with a 3- or 4-mm diameter punch, which is driven perpendicularly into the nail plate in a circular motion down to the bone. However, it is not always easy to extract the cylinder cut with an area this small. One useful technique is to perforate the nail plate with a 6-mm punch without injuring the underlying tissue (see Fig. 245-13A). The covering nail is then detached by using the tip of the scalpel to remove the disk of nail, and the biopsy is performed easily by using the 4-mm punch to the bone. The tissue can then be released from its tether with fine scissors. It is advisable to replace the 6-mm disk of nail keratin, after cleaning with 10% hydrogen peroxide, to cover the hole. If the nail plate is thick, rotating grinders can be used to thin it down and facilitate the transungual biopsy.
If a larger nail bed fragment is needed, fusiform biopsy with a major longitudinal axis can be performed after partial avulsion of the lateral half of the nail (see Fig. 245-13B) or after total avulsion if the fragment is central. After excision, the nail bed is undermined to facilitate reapproximation of both sides. The suture needle is used generously on these fragile subungual tissues. The wound is stitched with 6-0 resorbable thread. It is sometimes useful to make relaxing incisions at the most lateral margins of the nail bed.
In cases of subungual hematoma, acute trauma with severe pain is always remembered by the patient. Depending on the site and intensity of the injury, the hematoma may be visible almost immediately or it may grow out from under the proximal nail fold within a few weeks.
When the hematoma is partial (less than 25% of the visible portion of the nail), it should be drained with a pointed scalpel or by hot paperclip cautery over the center of the dark spot (Fig. 245-14). This will produce relief from pain. Sometimes the nail sloughs as the new nail regenerates beneath the old one.
Treatment of partial hematoma.
Small hematomas may be included in the nail, but they cannot be degraded to hemosiderin and results of the Prussian blue test will be negative. Therefore, to demonstrate the nature of the blackish pigment, scrapings are boiled in a small test tube with Hemostix, which gives a positive benzidine result.
A hematoma involving more than 25% of the visible portion of the nail is a sign of significant nail bed injury. A radiograph is mandatory, because the phalanx may be fractured. The nail plate is carefully removed and the hematoma evacuated. Traumatic nail bed laceration or wounds need a surgical approach to avoid delayed complications.
Nail bed lacerations can be sutured after thorough cleaning with antiseptics, using 6-0 resorbable monofilament material. The avulsed nail plate should be put back to cover the wound and then kept in place by suturing to the lateral nail folds or the fingertip.
Nail bed defects larger than 4 mm can be repaired using a split-thickness graft taken either from the nail bed of the same digit or from the nail bed of a great toe.
The torn nail bed should be sutured with 6-0 resorbable thread, and large bites of tissue should be taken so that the suture material does not pull through when it is tied. The nail plate is cleaned, shortened, and slightly narrowed, and then replaced with sutures into the lateral nail folds. The stitches are left in for 2 weeks.
Chronic hematomas are usually painless and are caused mainly by repeated microtrauma from either ill-fitting footwear or sporting activities. A notch is made with a scalpel blade at the distal and proximal border of the pigmented spot. Observation over a 3-week period will demonstrate whether the nail grows independently of the pigmentation or with it. However, chronic hematoma may resemble subungual melanoma and pose a distressing problem, and nonmigrating hematoma should be ruled out.
A 2- to 3-mm punch may be used for biopsy of a tumor. A blister may be completely removed by shave biopsy using half a razor blade (see eFig. 245-14.1). Excision of a 3-mm crescent-shaped tissue segment in the proximal region of the lateral nail folds may be helpful in the evaluation of collagen disease.
Proximal nail-fold shave biopsy.
Recalcitrant Chronic Paronychia
Presence of a foreign body (e.g., hair) under the proximal nail fold is the main cause of recalcitrant chronic paronychia. The disorder manifests as a red swelling that is painless except when pressed, with secondary retraction of the paronychial tissue whose cuticle has disappeared and with recurrent episodes of acute paronychial inflammation.
For crescentic excision, a Freer septum elevator is inserted under the proximal nail fold to protect the matrix and extensor tendon. A No. 15 Bard-Parker blade is used to excise, en bloc, a crescent-shaped full-thickness skin segment, 4 mm at its greatest width, that extends from one lateral nail fold to the other. Use of a beveled incision prevents accidental damage to the proximal nail matrix and the most proximal portion of the proximal nail fold, which is responsible for the normal shine of the nail plate (see eFig. 245-14.2).
Crescentic excision of the proximal nail fold.
In patients who experience repeated acute flares associated with chronic paronychia, additional removal of the base of the nail is useful.
Tumors of the Proximal Nail Fold
Different techniques can be used to treat tumors of the proximal nail fold, depending on the nature of the tumor, its location, and the length of its long axis.
Crescentic excision is useful for small distal tumors. The crescent should not exceed 4 mm at its greatest width.
Tumors of the proximal nail fold that are situated in a median position and have a longitudinal axis longer than 4–5 mm can be excised with a wedge of proximal nail fold whose base is located at the free margin and whose apex points proximally (Fig. 245-15A). Two relaxing lateral incisions are then made in the proximal nail fold to allow suturing of the wedge-shaped defect after the undersurface of the proximal nail fold has been released from the nail plate (see Fig. 245-15B).
A. Tumor of the proximal nail fold situated in a median position. B. Suturing of the defect after relaxing lateral incisions are made and the proximal nail fold has been released from the nail plate.
The resulting symmetric narrow defects on both sides heal rapidly by secondary intention.
A small tumor on the lateral part of the proximal nail fold may be treated using a wedge-shaped excision (see eFig. 245-15.1). Only one lateral relaxing incision is made at the opposite region of the proximal nail fold. To obtain better healing of the secondary defect, which is wider than in the procedure using two relaxing incisions, the surgery may be supplemented by making a relaxing crescent-shaped incision in the proximal nail fold.
A. Irregular shape of the distal border of the proximal nail fold. B. Crescenting wedge-shaped excision of the proximal nailfold. C. Two months after healing.
A dorsal flap can be raised from the proximal nail fold by using two dorsolateral incisions and a horizontal one proximal to the cuticle. This gives complete exposure of subcutaneous tumors.
Reconstruction of the Proximal Nail Fold
Reconstruction of the proximal nail fold may be necessary after any injury (accident, burn, avulsion caused by rapidly rotating belts and sanders, etc.). If the irregular tissue is excised, it is sometimes possible to recreate the distal curve of the proximal nail fold, which may produce a nearly perfect restoration. The proximal nail fold may also be restored by using two long, narrow, V-shaped transposition flaps from the lateral aspects of the terminal phalanx.
A 2- to 4-mm punch can remove a tumor of the lateral nail fold (see eFig. 245-15.2). Benign tumors may be removed by taking an elliptical wedge of tissue from the lateral nail fold and lateral nail wall. Malignant tumors, such as in Bowen disease, are treated by excision of the whole lateral nail fold or by Mohs micrographic surgery followed by healing by second intention.
Biopsy techniques involving the lateral nail fold.
Ingrown nail is a condition that occurs mainly in the great toe. It is created by impingement of the nail plate into the dermal tissue distally or into the distolateral nail groove. Irrespective of the initial cause, the condition finally presents with a nail bed that is too narrow for its nail plate. Logical treatment is therefore aimed at correcting this disparity.
Surgical avulsion or the loss of the toenail from trauma, such as tennis toe, may initiate the pathology. The distal subungual tissues released from the physiologic counterpressure of the nail plate become hypertrophic, and the newly formed nail plate abuts this distal wall. To treat the condition, a crescentic wedge-shaped excision is made around the distal phalanx (see eFig. 245-15.3). The wedge should be 4 mm at its greatest width and must be dissected from the bone. The defect is closed with 5-0 monofilament sutures, which should be removed after 12–14 days.
Surgical treatment for distal nail embedding.
Retronychia represents proximal regrowth of the nail that occurs when the nail embeds backwards into the proximal nail fold. Sonography is a useful tool to diagnose easily this condition. Nail-plate avulsion with supplementary medical management is curative.
Juvenile (Subcutaneous) Ingrown Nails
Juvenile or subcutaneous embedded nail is the most common type of ingrown nail. The nail is usually embedded medially, but both sides are often affected. In an effort to relieve the pain, the patient often tries to cut off the offending corner under the inflamed and swollen soft tissue. The remaining portion gives rise to a nail spicule piercing the epithelium of the lateral nail groove, which produces secondary infection and excessive granulation tissue.
Treatment at the early stage must be conservative but demands a high degree of patient compliance. The foot is soaked in warm water with povidone-iodine soap; then, under local anesthesia, the nail spicule is removed and a wisp of cotton wool is placed between the nail and the lateral nail groove. It should be moistened repeatedly with a disinfectant.
For definitive cure, surgical excision or, better, chemical suppression of the lateral horn of the nail matrix permanently narrows the nail. The lateral fifth of the nail plate is freed with a nail elevator from the proximal nail fold and the subungual tissues. It is then cut longitudinally with an English nail splitter or nail-splitting scissors and extracted using a sturdy hemostat. The lateral matrix horn is cauterized with a freshly made solution of liquefied phenol (88% solution) (see eFig. 245-15.4). Above all, a bloodless field is needed, because blood inactivates phenol. Hemostasis is therefore accomplished with a tourniquet, and the blood is carefully cleaned from the space under the proximal nail fold using sterile gauze. The surrounding skin is protected with petroleum jelly. The phenol is rubbed onto the matrix epithelium for 3 minutes with a cotton-tipped swab that is changed two or three times. Postoperative pain is minimal because phenol has a local anesthetic action and is antiseptic. The matrix epithelium is sloughed off, and oozing is usual for 2–6 weeks. Daily warm foot baths with povidone-iodine soap accelerate healing.
A. Juvenile ingrown nail with excessive granulation tissue. B. Phenolization of the lateral matrix horn.
Besides phenol and sodium hydroxide, 100% trichloracetic acid has been performed for partial matricectomy. The wound almost always heals within 2 weeks without prolonged exsudative discharge. Pain is mild and transient.
Overcurvature of the nails may affect the great toe alone or all the digits. This condition may be so painful that even contact with a bedsheet becomes unbearable.
When the condition is mild, the nail brace technique aims at correcting the inward distortion of the nail by maintaining continuous tension on the nail plate. A stainless steel wire brace is fitted to the nail plate. A series of adjustments adapted to the gradual decrease of curvature is made over a period of 6 months and results in a painless correction of the pincer nail. Because the underlying bone pathology remains untreated, however, relapse is usual. Therefore, the definitive cure—the use of phenol cautery on the lateral matrix horns—is undoubtedly the simplest effective treatment modality.
Hypertrophy of the Lateral Nail Fold
Hypertrophic lateral nail folds are usually the result of long-standing ingrown nails. Inflammation may range from the subclinical to the severe. For treatment, approximately one-fifth of the nail digging into the lateral nail fold is removed. Then an elliptical wedge of tissue is taken from the lateral nail wall of the toe, down to the bone (see eFig. 245-15.5). Suturing of the defect pulls the lateral nail fold away from the offending lateral nail edge. In severe cases, this procedure may be combined with phenol cautery of the lateral horn of the matrix. In contrast to adult-acquired hypertrophy of the lateral nail fold, congenital lateral hypertrophic lips disappear progressively and spontaneously within 12 months.
Surgical treatment of hypertrophy of adult lateral nail fold.
Congenital Malalignment of the Great Toenail8
In congenital malalignment of the nail of the great toe, typically the nail is malaligned laterally, with transverse furrows on a thick brownish or greenish nail. In 50% of cases, this condition corrects itself without therapy before the age of 10. If the appearance is extreme, surgery diminishes the risk of permanent dystrophy.
Treatment requires rotation of a bulky nail unit flap, including the entire nail, nail bed, and matrix (see eFig. 245-15.6). This demands creation of an external Burow's triangle. An eccentric crescent-shaped excision is made to undermine the nail unit, with the maximum width located on the internal side of the foot, corresponding to the side to which the nail needs to be redirected. This crescent ends on each side 3–4 mm behind the most proximal part of the proximal nail fold. The nail bed and the matrix are then undermined and lifted until the fibers of the extensor tendon are visible on its bony insertion, and the dorsal expansion of the lateral ligament of the distal interphalangeal joint is cut.
Surgical treatment of congenital malalignment of the nail of the great toe.
Suturing the edges of the excised triangle together reduces the loss of cutaneous substance. The nail unit is rotated inwardly, because the maximum cutaneous resection is mostly distal and medial.