Excision of Nailbed Remnant following Finger Amputation

Procedure: This video depicts the excision of a nail remnant from the stump of an amputated left thumb in a 17-year-old male. Introduction: Fingernail remnants following distal fingertip partial amputations cause pain and are a common reason for amputation revisions. Removal of these nail remnants is a straightforward procedure that can be performed by the plastic surgeon to significantly improve the patient’s quality of life and function. Indications/Contraindications: Excision of the nail matrix and nail bed is indicated for patients with painful nail remnants following surgery, or if the remaining nail matrix after amputation is too small to grow a functional nail. There are no absolute contraindications to this specific procedure, aside from contraindications for elective hand surgery in general, including active infection, and uncontrolled diabetes. Materials and Methods: An incision was made at the most distal aspect of the amputated thumb in order to avoid the extensor tendon. The nail remnant was and the bone underlying it was probed with a rongeur to ensure that it was completely removed. Results: The incision edges were approximated and closed primarily with simple interrupted sutures. The patient was pain-free and was discharged home from outpatient surgery. Conclusion: This report demonstrates how to perform an important and useful revision that is often indicated following digital partial amputations.

Purpose of technique: The fingernail is a plate of hardened keratinized epithelial cells attached to a nail plate. Its function is to act as a counterforce to the fingertip pad, which increases its sensitivity and two-point discrimination. It also aids in grasping and lifting small objects. Fingertip injuries account for over 4.8 million emergency department visits per year, with pediatric patients making up over two thirds of these cases. Crush injury to the fingertip is common among pediatric patients, and often results in damage to the nail bed and its matrix1. Proper patient/case selection (indications): In a case study including 125 distal phalanx amputations, 91 were complicated by postoperative nail remnant. This nail remnant can irritate the overlying dorsal skin flap and cause pain3. Fingertip amputations that damage but do not completely ablate the germinal matrix often result in either painful nail remnants or hook nail deformities3. Amputations proximal to the lunula (which typically spare at least some of the germinal matrix) have the highest likelihood for needing secondary surgery to remove nail remnants or correct hook nails3. This may be even more important in pediatric patients, in whom nail growth is accelerated twofold1. For patients who have pain from a remnant fingernail following distal finger amputation, and for patients with less than 5mm of sterile matrix remaining (i.e. not enough to produce a functional nail)5, amputation revision with nail excision is an indicated surgery3,4. Contraindications (absolute and relative): There are no absolute contraindications to surgical excision of the nail remnant in these patients, and the only relative contraindications are those that apply to all surgery on the fingernail, specifically peripheral vascular disease, diabetes mellitus, collagen vascular disease, disorders of hemostasis, or active infection of the nailbed6. Advantages and disadvantages over alternative techniques: There is some ambiguity in the literature about whether or not ablation of the nail matrix should be done primarily or as part of an amputation revision. Because of its important function in augmenting the sensitivity of the finger pad, preservation of the nail matrix is recommended because it preserves the possibility of a functional nail. In the event the nail matrix survives, the new nail will have a severe hook deformity, which will require surgical correction in the future3. The decision to excise or leave the nail bed at the primary closure of an amputation should be made with the patient preference in mind. Complications and risks: Excision of the nail remnant carries relatively few complications outside of the typical risks of hand surgery, and it eliminates the future potential for having a functional nail in the future. Additionally, excision of the nail matrix carries a very low risk of damage to the extensor tendon if it is still intact.

Instrumentation: Surgical instruments should include an 11 or 15-blade scalpel, periosteal elevators, assorted retractors, and a rongeur. Setup: This procedure can be performed under local anesthesia with monitored anesthesia care (MAC) with a proximal digital block using 1% lidocaine with epinephrine. Digital block should target the radial and ulnar digital nerves of the thumb, as well as field block of the dorsal and volar aspects of the thumb (0:04). A bloodless surgical field was maintained with an elastic finger tourniquet (0:22). Preoperative workup: Preoperative workup is not different than what is required for routine hand surgery. Smoking cessation should be encouraged before performing this surgery, as should good blood glucose control. Anatomy and landmarks with figures as needed: The germinal matrix (Figure 0:11) is responsible for 90% of nail production, and extends deep to the eponychium and terminates just distal to the extensor tendon insertion7. The sterile matrix, which underlies the nail plate distal to the germinal matrix, is responsible for the other 10% of nail production, and is primarily responsible for nail adherence and normal nail form7. The nail plate (Figure 0:20) is bordered proximally by eponychium, and distally by the hyponychium, with the paronychium on either side. The white arc distal to the eponychium is the lunula, which gets its color from the nail cell nuclei in the germinal matrix deep to it. Detailed steps to procedure: The nail remnant is identified on the dorsal aspect of the amputation stump of the left thumb, distal to the distal skin fold. The incision should be planned as distal as possible in order to avoid the extensor pollicis longus tendon inserting on the base of the distal phalanx (0:41). A 1-cm-wide elliptical incision is made around the nail remnant at the distal tip of the thumb. The tip of the 11-blade should probe deeply to the remaining bone of the distal phalanx, in order to ensure full excision of the nail remnant (0:50). The nail remnant is excised sharply with a scalpel (1:25). The skin edges of the incision should be retracted to allow full visibility of the nail matrix, periosteum, and bone, and the remaining nail matrix should be excised by probing the dorsal aspect of the incision with a rongeur (2:25). If there is not enough skin laxity to close the incision, local skin flaps may be raised by undermining the wound edges. The incision should then be closed primarily with simple interrupted 4-0 chromic gut sutures (2:34).

A positive outcome from nail remnant excision should leave the patient pain free from the irritating nail remnant, and with no functional deficit in flexion, extension, or sensation compared with the pre-operative exam. Post-operatively, the patient should be pain free in the left thumb with no change in their range of motion or neurovascular exam from pre-operatively. There should be no tenderness to palpation anywhere on the thumb stump. A poor outcome of this surgery would include damage to the adjacent digital nerves or arteries, as well as recurrence of the nail remnant, which would require additional surgery.

Critical steps of the procedure: The critical step of this procedure is removal of the most proximal portion of the germinal matrix sharply with a rongeur (3:09). Failure to perform this step adequately will result in recurrence of the nail remnant, which will cause pain and require further surgery. Common modifications: While local anesthesia with proximal digital block is usually sufficient for nail remnant excision in most cases, there may be patients (particularly children) who might not tolerate this and require a higher level of sedation. Depending on the extent of the initial amputation and the size of the nail remnant remaining, a larger incision may be required to fully excise all of the germinal matrix. In larger cases this may require surgical exposure and identification of the extensor tendon. Common pitfalls: The most common pitfall of this surgery is failure to fully excise the germinal matrix. The final step of dorsal excision with a small rongeur is critical to ensure that the entire germinal matrix is ablated. Failure to do so can result in recurrence of the nail remnant, pain, and need for future surgery, which needlessly increases cost to the patient and health system. Troubleshooting of the technique(s): This elliptical incision for removal of the nail remnant is an easy operation that provides clear improvement in the patient’s quality of life, by reducing their pain and maintaining extensor function of the finger stump. Limitations of the technique: This technique is limited to excision of nail remnants following partial fingertip amputation, but does not restore any function to the hand or finger. Potential further applications of the technique(s): This technique can be applied to any painful nail remnant on any partially amputated digit, though nailbed excisions on toes may not be amenable to a digital tourniquet and may require more proximal compression for a bloodless field. Knowledge of how to perform this procedure is very useful to any hand surgeon as removal of painful nail remnants is a very common surgery that is required after crush injuries or partial amputations of the fingertip.

The authors of this manuscript have no conflicts of interest to disclose.

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