Given that podiatrists perform nail surgery procedures daily in the office, this author discusses pertinent and emerging insights about partial nail avulsions as well as nail biopsy techniques.
Whether it is a partial nail avulsion for an ingrown toenail or performing a shave biopsy of a pigmented lesion at the nail matrix, nail surgery procedures are among the more common procedures we perform as podiatrists.
Prior to performing any toenail procedure, it is imperative to examine and obtain the consent of the patient. Patients should present free of nail polish or other adornments on the affected foot. When it comes to ingrown toenails, note the level of pain as well as the presence of infection, erythema, edema, granulation tissue and drainage.
It is also helpful to note if there is an underlying biomechanical cause of the ingrown toenail as is often the case in the hallux nail of a patient with a bunion deformity. A thorough history detailing the patient’s previous treatment of an ingrown nail (whether by a physician or via “bathroom surgery”) and the outcome of said procedures should be part of the discussion. Of course, the patient’s medical history and vascular status (including any relevant history of Raynaud’s phenomenon and pernio) are imperative in determining if the patient can have nail surgery.
For suspected tumors, both benign and malignant, a personal and family history of skin cancer can be helpful in the surgeon’s differential diagnostic process. In these cases, one should note any destruction of the nail plate from the tumor, discoloration of the nail plate and periungual tissue, and the pain level.
Addressing Ingrown Toenails
Ingrown toenails can cause significant pain and disability to the patient.1 They can present as a painful onychocryptosis or incurvation of the lateral edge of the nail plate with or without lateral nail fold edema or redness. Ingrown toenails also can present as a paronychia with pain, focal erythema, swelling, drainage, granulation tissue and possible hypertrophy of the periungual tissue. There are multiple conservative methods such as the “slant back” procedure, gutter splinting, taping the lateral nail fold and massage of the nail fold. However, these methods require patience and time on the patient’s part.
For those patients in whom conservative therapy has failed or in whom the presentation is too severe for a non-surgical intervention, a partial nail avulsion of the affected side is indicated. The purpose of this procedure is to decrease the width of the nail plate of the offending nail border to relieve pain and pressure. This certainly can extend to include removal/destruction of the nail matrix either surgically or chemically in order to cause long-term narrowing of the nail plate.
What The Literature Reveals About Phenol And Partial Nail Avulsions
While there are many variations of performing a partial nail avulsion (originally described by Ross), let us take a closer look at adjunctive interventions with this procedure.2
Following a partial nail avulsion, one can perform a chemical matrixectomy utilizing either phenol or sodium hydroxide. In 1945, Boll was the first to describe the use of phenol following a partial nail avulsion.3 Phenol, a weak organic acid, is both lipophilic and hydrophilic. It is highly soluble in organic solvents like isopropyl alcohol, which ultimately is the best treatment for phenol burns. Many practitioners will follow the phenol application with a lavage of alcohol. However, irrigating the newly “phenolized” area with alcohol, a weak acid, to “neutralize” the phenol is under debate in the literature.
Recent studies have shown that the amount of phenol recovered (i.e., removal of phenol) when one irrigates the area with either polyhexanide (PHMB) (Prontosan, B Braun Medical) or sterile saline solution is greater than irrigation with alcohol.4,5 Ultimately, alcohol and the other solutions observed in these studies do not neutralize phenol. They simply serve to dilute it and aid in its removal.5
Researchers have described nail phenolization following a partial nail avulsion as the definitive method of decreasing the width of the nail plate with less recurrence in comparison to partial nail avulsion alone.6 In addition, there is no significant difference in recurrence when using phenol versus sodium hydroxide to perform a chemical matrixectomy following a partial nail avulsion.
The suggested time and amount of phenol varies from practitioner to practitioner depending on training and experience. Two studies focused on determining the amount of time and applications that will effectively destroy matrix cells. Boberg and colleagues utilized nail specimens obtained from patients who had ingrown toenails.3 Physicians applied an 89% phenol solution for 30 seconds, one minute, 90 seconds and two minutes to the nail matrix. After 30 seconds, the basal layer was intact, which would imply recurrence is likely. The one-minute application of 89% phenol showed complete destruction of the basal layer while the 90-second and two-minute applications not only showed basal layer ablation, but necrosis of the dermis as well.
However, when Becerro de Bengoa Vallejo and coworkers examined the application of phenol 88% to fresh cadaveric hallux nail samples, they found that a one-minute application left the basal layer of the epithelium intact.7 After studying up to six minutes of application, researchers determined that four minutes of application completely destroyed the nail matrix.
The Boberg study supports the wide podiatric use of the Phenol EZ Swab (Valeant Pharmaceuticals), which is 89% phenol intended for a single dose, one-minute application.3 Ultimately, further studies are needed not only to determine the amount of exposure required to destroy nail matrix cells but the rate of recurrence in the presence or absence of infection as well.
Phenolization of the nail matrix has side effects of postoperative drainage and pain. Two studies examined the use of sodium hydroxide and its potential side effects. Bostancı and colleagues described three patients who developed allodynia, nail dystrophy and hyperalgesia after having a 10% sodium hydroxide chemical matrixectomy.8 However, there are limited reports in the literature of postoperative complications from the use of sodium hydroxide so one can consider these complications rare until a larger study or case series demonstrates otherwise.
Recently, Grover and coworkers compared 88% phenol to 10% sodium hydroxide following partial nail avulsion.9 Due to phenol causing coagulation necrosis versus the liquefaction necrosis visible with the base amount of sodium hydroxide, the side effect profile with sodium hydroxide in theory should be of a lesser nature. The patients in this study had less recovery time than those in the Bostancı study.8 However, Grover and colleagues used a one-minute application time of sodium hydroxide in comparison to a three-minute application time, which could lessen side effects. Authors note the shorter application time reduced side effects.
What About Following A Partial Nail Avulsion With A Surgical Matrixectomy?
Partial nail avulsion followed by a surgical matrixectomy is certainly an option but researchers have described debulking of the periungual soft tissue when hypertrophy of the nail folds is contributing to the lateral nail pain.6
There are two techniques: the Howard-Dubois procedure and the super U procedure.1 One would utilize the Howard-Dubois procedure for mild to moderate cases while the super U procedure is indicated for severe presentations and involves more tissue removal. Both involve incisions encompassing the distal, lateral and medial aspects of the nail unit in order to debulk the soft tissue effectively.
When performing the Howard-Dubois procedure, one would make a fish-mouth incision parallel to the distal nail and running medial and lateral to the distal interphalangeal joint. A second incision creates a wedge that one will remove in order to remove excess soft tissue. This technique can also reduce the bulk for an embedded distal toenail edge, which will ultimately allow that nail to progress forward.
Both procedures will require appropriate postoperative care and some downtime, especially if one performs the super U procedure.
Keys To Performing Nail Plate Biopsies
Let us first distinguish between a nail plate biopsy for onychomycosis and a nail biopsy to diagnose a tumor.
A nail plate “biopsy” is a specimen one takes from the nail plate and subungual debris for periodic acid-Schiff (PAS) staining or KOH/nail culture. This technique does not require anesthesia (unless you are trying to diagnose proximal subungual onychomycosis) and simply requires an alcohol swab, a nail nipper and a curette. If you are sending a specimen for KOH/fungal culture to determine which species is causing distal subungual onychomycosis, first wipe the nail with an alcohol swab and then debride the distal tip of the nail plate. Discard that distal nail plate specimen you just debrided. That nail specimen has dry, desiccated hyphae that may not grow on culture medium.
Instead, use a small curette to remove the subungual debris under the nail plate as proximal as possible and send that debris for culture. The subungual debris will provide a more viable specimen for culture growth at the lab. For a PAS stain, I suggest sending the nail plate with some subungual debris.
When There Are Suspicious Pigmented Streaks Or Lesions At The Nail Unit
When it comes to a biopsy for longitudinal pigmented streaks or longitudinal melanonychia, clinicians can use a variety of methods. Longitudinal melanonychia can result from a variety of issues, notably nail unit melanoma, melanocyte activation, natural variation (seen in the skin of patients of color), medications and fungal infections. For pigmented streaks near the midline of the nail that are less than 3 mm wide and originate in the distal matrix, Jellinek recommends performing a 3 mm punch biopsy.10 One can perform the punch biopsy through the nail plate or avulse the nail plate and perform the punch biopsy in the nail bed. This is also the technique for sampling the nail plate for proximal subungual onychomycosis.
For similar lesions that are greater than 3 mm wide, one may do a matrix shave biopsy. For wider bands that are laterally oriented and give rise to suspicion of melanoma or squamous cell carcinoma, a longitudinal excision may provide the most adequate sample to pathology.
As Jellinek discussed, the shave biopsy of a pigmented lesion at the nail matrix involves two incisions at the proximal nail fold in order to reflect the nail fold back and expose the proximal nail plate and matrix.10 Using an English anvil nail splitter, make a window of the nail plate and reflect it laterally in order to expose the pigmented lesion underneath. Using a 15 blade and maintaining a 1 to 2 mm peri-lesion margin, make a shaving motion parallel to the tissue. As the specimen may curl, one may place it on a piece of paper in formalin for tissue processing. Jellinek recommends extending the window of the nail plate to facilitate tissue edema.10 One can then replace this window of nail as a biologic dressing and suture it to either the nail fold or the nail plate with subsequent suturing of the proximal nail plate.
When faced with a laterally oriented pigmented streak, making a lateral nail excision will allow you to sample the nail plate, nail bed and matrix. Using a 15 blade, make an elliptical or curvilinear type of incision, extending laterally to the nail plate, proximal and distal, involving not just the nail but the surrounding tissue. This allows total excision of the total nail unit to the level of the bone in this area in addition to the nail matrix. It is imperative that the physician determines that he or she has removed all of the nail matrix in order to prevent spicules and painful regrowth. Suture the proximal nail fold to the remaining lateral nail fold, suture the lateral nail fold to the remaining nail plate, and suture the nail plate to the hyponychium.
Nail surgery is a key office procedure for podiatric physicians to utilize for both relieving pain from ingrown nails and diagnosing nail unit tumors. Having the ability to perform these techniques in the office allows the physician to offer the patient a procedure with a local anesthetic and minimal downtime.
Dr. Vlahovic is an Associate Professor and J. Stanley and Pearl Landau Fellow at the Temple University School of Podiatric Medicine. She writes a monthly blog for Podiatry Today. Readers can access Dr. Vlahovic’s blog at http://tinyurl.com/qbe6s4w .
- Di Chiacchio N, Di Chiacchio NG. Best way to treat an ingrown toenail. Dermatol Clin. 2015; 33(2):277–282.
- Ross WR. Treatment of the ingrown toenail and a new anesthetic method. Surg Clin North Am. 1969;49(6):1499-504.
- Boberg JS, Frederiksen MS, Harton FM. Scientific analysis of phenol nail surgery. J Am Podiatr Med Assoc. 2002;92(10):575-9.
- Cordoba Diaz D, Becerro de Bengoa Vallejo R, Losa Iglesias ME, Cordoba Diaz M. Polihexanide solution is more efficient than alcohol to remove phenol in chemical matricectomy: an in vitro study. Dermatol Ther. 2014;27(6):369-72.
- Cordoba Diaz D, Losa Iglesias ME, Cordoba Diaz M, Becerro de Bengoa Vallejo R. Enhanced removal of phenol with saline solution over alcohol: an in vitro study. Dermatol Surg. 2012;38(8):1296-301.
- Eekhof JA, Van Wijk B, Knuistingh Neven A, et al. Interventions for ingrowing toenails. Cochrane Database Syst Rev. 2012;(4):CD001541
- Becerro de Bengoa Vallejo R, Cordoba Diaz D, Cordoba Diaz M, Losa Iglesias ME. Alcohol irrigation after phenol chemical matricectomy: an in vivo study. Eur J Dermatol. 2013;23(3):319-23.
- Bostancı S, Koçyiğit P, Güngör HK, Parlak N. Complications of sodium hydroxide chemical matrixectomy: nail dystrophy, allodynia, hyperalgesia. J Am Podiatr Med Assoc. 2014;104(6):649-51.
- Chander G, Ananta K, Bhattacharya SN, Sharma A. Controlled trial comparing the efficacy of 88% phenol versus 10% sodium hydroxide for chemical matricectomy in the management of ingrown toenail. Indian J Dermatol Venereol Leprol. 2015; 81(5):472-477.
- Jellinek N. Nail matrix biopsy of longitudinal melanonychia: Diagnostic algorithm including the matrix shave biopsy. J Am Acad Dermatol. 2007;56(5):803-10.
For further reading, see “When Should You Biopsy?” in the June 2013 issue of Podiatry Today or “Diagnosing And Treating Pigmented Nail Lesions” in the October 2014 issue.
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