Chapter 87 Disorders of Nails and Skin
Anatomy
The normal nail complex consists of the nail plate, the nail bed, and the surrounding skin. The nail plate is the nail proper and consists of two components: the root, the portion of the nail plate that is beneath the skin, and the body, the exposed portion of the nail plate. The nail bed, has two components, the sterile matrix and the germinal matrix. In the skeletally mature foot, the germinal matrix extends from just distal to the lunula 5 to 8 mm proximally and deep to the eponychium or proximal nail fold. It is smoother and paler than the sterile matrix, unless the nail has recently been avulsed. The germinal matrix sends projections into the adjacent soft tissue that make complete nail ablation difficult. The germinal matrix contributes to longitudinal growth of the nail plate (Fig. 87-1A). The skin surrounding the nail plate includes the nail walls (labia ungues), the margins of skin that overhang the two lateral borders of the nail body; eponychium (proximal nail fold), the distal extension of the stratum corneum of skin that covers the nail root; and cuticle, the distal edge of the eponychium. It is doubtful that the eponychium, lateral nail folds, or nail bed (sterile matrix) contribute to longitudinal new growth of the nail plate, but this issue is not completely settled. Finally, the hyponychium is the horny thickening of the skin at the distal margin of the nail.
Ingrown Toenail (Onychocryptosis, Unguis Incarnatus)
Etiology
The term ingrown toenail is misleading. If used to designate a hook of nail caused by improper nail care growing into an overlapping nail fold that has obliterated the lateral nail groove, the term is acceptable (Fig. 87-1B). The most probable cause of the symptom complex is a combination of factors, however, only one of which may be an improperly trimmed nail. The condition is rare in people who do not wear shoes, and the most likely explanation is the absence of extrinsic pressure. Within the confines of the shoe toe box, the great toe is pushed toward the second toe, resulting in pressure against the lateral border of the nail, while the shoe itself exerts pressure on the medial side of the nail. This extrinsic pressure causes the nail fold to push into the sharp edge of an improperly cut nail, breaking the skin. The bacterial and fungal flora on the skin enter the open wound, albeit a small one, and inflammation results. A bottlenecked, poorly draining abscess follows, causing erythema, edema, hyperhidrosis, and tenderness. Finally, hypertrophic granulation tissue completes the clinical picture of the familiar infected ingrown toenail (Fig. 87-1C). The hypertrophic granulation tissue is slowly covered by epithelium, further inhibiting drainage and promoting edema. This process makes the nail even more vulnerable to injury by extrinsic pressure, and the cycle repeats itself.
Nonoperative Management
Stage I (Inflammatory Stage)
In stage I, the patient has mild erythema, swelling, and tenderness along the lateral nail fold. The treatment involves lifting the lateral edge of the nail plate from its embedded position in the dermis of the lateral nail fold. This is easier to perform if done after soaking the foot, which makes the nail softer and more pliable. Nonabsorbent cotton, wool, or acrylic mesh is passed beneath the corner of the nail (Fig. 87-1D). This is done gently because it is frequently painful. The patient may need a few days of intermittent warm soaks, a cutout shoe, and modification of activity before the local inflammation is reduced enough to allow this treatment. Once begun, however, the patient usually can introduce more material beneath the nail corner than can the physician. The patient repeats the treatment daily until the nail grows out and can then be trimmed properly. Proper trimming of the nail at right angles to the distal edge of the nail plate is shown in Figure 87-2, with the goal being a squared nail with corners protruding distal to the hyponychium. This treatment usually is successful in 2 to 3 weeks if as much material as is comfortable to the patient is placed beneath the nail edge each day.
Another conservative treatment option is nail splinting, which separates the nail plate from the soft tissue to provide a channel in which the nail can grow. A “gutter splint” that is affixed to the ingrown nail edge with adhesive tape or a formable acrylic resin such as cyanoacrylate can be fashioned from a sterilized vinyl intravenous drip infusion tube slit from top to bottom with one end cut diagonally for smooth insertion (Fig. 87-3). Gutter splints can be used with or without the application of an acrylic nail. The use of a resin splint also has been reported to be successful, although the duration of application was lengthy (9 months). Reported recurrence rates with various splinting techniques range from 8% to 48%.
A dynamic correction technique, orthonyxia, uses direct force to lift the nail from the nail fold and release the pressure exerted on the inflamed soft tissue. Generally, orthonyxia devices consist of two hooks placed on the sides of the nail and connected under tension by wire (Fig. 87-4), “super-elastic” wire, or shape-memory segments. Correction of the nail deformity has been reported to occur within 3 weeks in most patients. Cited advantages of splinting and orthonyxia techniques over operative treatment are less postoperative morbidity, shorter time to recovery, and better cosmetic results.
Total Nail Plate Removal
When the great toe has been anesthetized, pass a straight, thin hemostat or small, flat nasal elevator beneath the nail in the midline from the hyponychium several millimeters proximal to the nail fold adjacent to the lunula (Fig. 87-5).
Another choice to remove the last moorings of the nail is the use of a wide, flat, nasal elevator.
Postoperative Care
A nonadherent, single-layer dressing is applied to the nail bed followed by a gently wrapped compression bandage. The foot is elevated for 24 hours, and then the dressing is removed and warm soaks are begun. No constricting hosiery or shoes should be worn for 1 week. The nail takes 4 to 6 months to re-form completely, depending on the patient’s age. The patient must be informed of this before surgery and forewarned that an upward-turned deformity of the distal nail bed and pulp may develop. This deformity is more likely to occur if the patient has had multiple nail avulsions (Fig. 87-6).
Partial Nail Plate Removal
Partial nail plate removal differs little from total nail plate removal.
Lift the lateral fourth of the nail from its bed with a small, angled probe or one arm of a narrow, smooth, straight hemostat, and remove it. Do not lift too firmly to avoid detaching the nail from its bed in a lateral direction.
The nail must be incised to its proximal end beneath the eponychium (Fig. 87-7).
The recurrence rate is even higher after partial nail plate removal than after complete removal. In adolescents, however, this minor procedure, even if it must be repeated, is an attractive alternative to changing the appearance of the nail permanently. The patient, and especially the parents of an adolescent, must be told that the nail-forming matrix may be injured, and some permanent deformity, even if minor, may result (Fig. 87-8).
Removal of the Nail Edge and Ablation of the Nail Matrix
All personnel involved in the procedure should wear gloves to avoid direct contact with phenol, which is caustic.
Place a tourniquet (Tourni-cot; Mar-Med Company, Grand Rapids, MI), Penrose drain, or a gloved finger at the base of the great toe to ensure a relatively dry dissecting area after placement of local anesthesia. Elevate the lateral fourth to fifth of the nail edge longitudinally from distal to proximal, including the few millimeters of nail that are beneath the eponychium (Fig. 87-9A).
When the nail plate has been removed, place antibiotic gel around the nail fold to protect the skin from the effects of the phenol (Fig. 87-9B and C). Place a small piece of cotton pledget that has been dipped in 80% to 89% phenol solution into the nail groove, extending beneath the eponychium to ensure that the pocket of germinal matrix is exposed to the phenol (Fig. 87-9D).
FIGURE 87-9 Removal of the nail edge and ablation of the nail matrix. A, Nail edge is elevated longitudinally. B and C, Antibiotic gel is placed around the nail fold to protect the skin. D, Cotton pledget dipped in phenol solution is placed in the nail groove. E, Nail is covered with nonadherent gauze and toe dressing is applied. F, Appearance of nail after phenol ablation. SEE TECHNIQUE 87-3.
Postoperative Care
The nail edge is covered with nonadherent gauze and a toe dressing (Fig. 87-9E), followed by release of the tourniquet. The patient is placed in a postoperative shoe and instructed to elevate the foot. The patient should be warned about the charred appearance of the skin that is evident when they remove their dressing after 2 to 3 days. Warm Epsom salt soaks are started once the dressing is removed, until the tissues have healed. Nonconstricting shoes are worn until all tenderness and drainage have ceased (Fig. 87-9F).
Partial Nail Plate and Matrix Removal
Technique 87-4
FIGURE 87-10 Winograd technique. A, Incision through nail plate and root. B, Removal of nail plate with exposure of nail matrix. C, Nail plate and adjacent matrix are excised. SEE TECHNIQUE 87-4.
Beginning 5 to 8 mm proximal to the lunula, make a longitudinal incision in the eponychium extending distally (Fig. 87-11A), while scoring, but not penetrating, the nail plate until its distal edge is reached (Fig. 87-11B).
Incise this nail margin with a nail splitter (Fig. 87-11C) along the previously scored mark, being sure to reach the most proximal edge of the nail plate.
With its eponychial cover already reflected, and the undersurface of the nail plate lifted off its bed (Fig. 87-11D), gently remove this segment of nail, exposing the underlying matrix (Fig. 87-11E).
Remove the exposed matrix by sharp dissection using the scalpel.
Retract the lateral nail fold to expose the lateral margin of the matrix. Remove the entire matrix, the sterile and germinal portions; take special care to remove the proximal portion of the germinal matrix to reduce the likelihood of recurrent nail formation (Fig. 87-11F).
Even after great care, the patient occasionally develops a tiny nail remnant that may or may not be symptomatic. An attempt to bring the lateral margin of the nail fold to the remaining nail is optional; Heifetz recommended excision of part of the nail fold. The surgeon should be certain that the periosteum of the phalanx has been removed with the matrix (Fig. 87-11G) because this is the most certain means of matrix ablation.
Return the proximal eponychial flap to its original location. Sutures to hold it there are optional (Fig. 87-11H).
Apply a nonadherent dressing over the exposed phalanx, followed by a nonconstricting gauze wrap (Fig. 87-11I).
FIGURE 87-11 Winograd technique. A, Eponychium is incised. B, Nail plate is scored. C, Nail splitter is used to divide nail. D, Small elevator lifts plate atraumatically from underlying matrix. E, Entire portion of plate, which has been removed from body of nail, is removed using straight hemostat. F, Pearly colored matrix is exposed. Matrix curves on undersurfaces of paronychium and eponychium. This must be thoroughly removed. G, Germinal matrix folding on eponychium and paronychium must be removed by sharp dissection from around nail horns. Nail plate and matrix have been removed completely. H, Closing wound is optional, but convalescence is shortened. I, Dressing remains in place for 24 to 48 hours. SEE TECHNIQUE 87-4.
