Introduction
Nails have many functions. First, it serves as protection for the fingers. Apart from being a mechanical tool, it adds aesthetic value to our fingers. A loss of nails can cause significant impairment in daily activities. Therefore, nail replacement and reconstruction are done to correct various nail conditions.
What Is Nail Replacement Surgery?
A nail consists of hard and soft tissue structures. The nail plate is a hard tissue composed of keratin. Underneath the nail plate is the nail bed, which comprises a nail matrix. The skin on the sides is called nail folds. Therefore, a thorough knowledge of these structures is necessary to perform a successful nail replacement surgery.
What Are the Indications for Nail Replacement Surgery?
Following are the indications.
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Congenital Conditions: Complete and partial absence of the nail is called anonychia congenita, and hyponychia congenita, respectively. These might cause aesthetic concerns in a patient.
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Trauma: Nail bed defects occur due to nail or fingertip injuries. Sometimes, pincer nail deformity arises after nail trauma. It denotes excessive curving and deformity of the nail plate. Nail bed reconstruction is done in such cases. The most common indications of nail reconstruction are simple lacerations, severe crush injuries, and nail avulsion. Another condition is a subungual hematoma (the blood collection under the nail plate following an injury). It leads to discoloration, pain, and swelling under the nails.
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Infections: Fungal infection of the nails is called onychomycosis. The nails can be surgically removed and replaced in recurrent onychomycosis.
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Tumors: Malignant melanoma, squamous cell carcinoma, and papilloma can affect nails. They are found under the nail plate. The tumors must be excised, and nail replacement can be done.
What Are the Different Types of Nail Replacement Surgeries?
Nail replacement surgery has a prerequisite. The reconstructed nail must simulate the original nail characteristics. Therefore, the surgery is difficult. Before surgery, a diagnosis of the condition is obtained. Different techniques for nail reconstruction are composite grafts, local flaps, dermal grafts, nail bed grafts from the big toe (the preferred technique), and microvascular nail transfer. A two-stage operation that comprises flap placement followed by nail bed grafting is mostly done in bone exposure or bone defect cases. A biopsy is sometimes performed to diagnose tumors. Local or regional anesthesia is used.
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Nail Bed Graft From Big Toe: After proper anesthesia, the hand and foot are prepared and draped. Under magnification, irregular edges are trimmed, and necrotic tissue is carefully removed. Then, after placing a tourniquet, an elevator is used to lift the nail plate to expose the nail bed. Surgeons should do this step cautiously to avoid any injury to the nail bed. Next, a split-thickness nail bed graft is taken from the toe. The graft is sutured into the defect using absorbable sutures. The raised toenail is sutured back into the original location. The grafted site is covered with a silicone sheet to simulate the nail plate shape. Finally, an antibiotic ointment is given as a dressing.
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Artificial Dermis: Sugamata et al., in 2012, reported using artificial skin (dermis) in 22 patients for nail regeneration. Artificial skin comprises polymers such as collagen, gelatin, or fibrin. Regeneration and elongation of nails were achieved in all patients resulting in their satisfaction. In 2022, Deng et al. performed nail reconstruction using double-layer artificial dermis (DLAD) on a male patient with a pincer toenail. DLAD is a novel material used in dermatology and surgery. It provides a scaffold for new tissue growth. Before applying, it is treated with saline for a few minutes to remove the superficial silicone layer. The remaining DLAD matrix consists of collagen and chondroitin sulfate complex. It is used to fill the nail bed tissue. The nail plate in the study was fully grown in all patients one year after the procedure.
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Composite Grafts: Composite grafts are also used in nail reconstruction. They contain two or more layers of soft tissue (mostly skin and cartilage). For example, Koh et al., in 2022, employed the two-stage surgical procedure with subcutaneous flap and composite graft for nail bed reconstruction in ten patients with crush injuries. Firstly, the flap surgery was performed. Then, three weeks later, a composite graft consisting of a nail bed and palm skin was done. The outcome was positive.
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Microvascular Nail Transfer: This procedure needs microsurgery. The indications in nail reconstruction are uncommon. However, it is used for partial or full nail cosmetic defects. The big toe is used as the most suitable donor nail.
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Local Flaps: After exposing the nail bed defect, a flap from the adjacent finger is taken. Further, the flap is transferred to the defect site and sutured. Yang et al. performed this technique along with a split-thickness toenail bed graft in 2017 on six patients. The results were favorable.
The complications include skin necrosis, decreased blood supply to the operated site, infection, and delayed wound healing. Sometimes, nail replacement is done with acrylic resin technology. About 15 % of the natural nail is required for the procedure. However, it should be noted that this procedure is purely cosmetic. It is not intended for disease improvement.
What Are the Contraindications of Nail Replacement Surgery?
There are no absolute contraindications for the surgery. However, a list of relative contraindications is given below.
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Peripheral Vascular Disease (PVD): A circulatory disorder where blood flow to the extremities is reduced.
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Acute Inflammation: Patients with acute inflammation of the nails are relative contraindications. Surgery must be postponed until the acute event has subsided.
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Diabetes Mellitus (DM): Patients with DM are prone to bacterial and fungal infections of the nails. Further, DM patients lose nerve sensation in the extremities (neuropathy).
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Bleeding and Clotting Disorders: Thrombocytopenia, hemophilia, and other bleeding and clotting disorders must be considered.
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Epinephrine Administration: Careful administration of epinephrine is required. Epinephrine is a blood vessel constrictor. Hence, in PVD patients, it might aggravate tissue death (necrosis) and poor wound healing. Furthermore, using a tourniquet for more than 15 minutes during surgery is not advised. It may lead to the blocking of the blood supply.
Conclusion
The outcome of the nail reconstruction depends on the patient's age, defect size, bone involvement, and timing of surgery. Nail replacement is a challenging procedure. Surgeons should accurately reproduce the results to ensure adequate functional and aesthetic results.
