Given that most podiatrists commonly perform nail surgery for conditions such as ingrown toenails, this author surveys the current literature and offers insights and nuances from her clinical experience on local anesthesia, treatment options, matrixectomy agents and approaches to retronychia.
Nail surgery, specifically for ingrown toenails, is a mainstay among office procedures for the podiatric physician. As with any surgical procedure, there are various ways of approaching and achieving the desired result. Accordingly, let us take a closer look at multiple aspects of ingrown nail surgery and keys to clinical decision making.
An imperative part of nail surgery is delivering local anesthesia. Technique and anesthetic drug preference are unique to each surgeon. Many podiatric physicians perform a proximal digital block at the base of the digit whereas some dermatologic surgeons and emergency room physicians may perform a more distal “wing” block at the base of the nail. The proximal digital block provides excellent anesthesia and does not interfere with the nail structure.1 As an infiltrative technique that focuses on anesthetizing the distal digit, the wing block purportedly has a faster onset of action but may cause blanching of the digit, possibly obliterating visual landmarks. This is especially important if one is seeking to perform a biopsy on a pigmented nail streak.
Regarding local anesthesia types, a clinician may choose lidocaine, bupivacaine or ropivacaine as agents for nail surgery. Clinicians often choose ropivacaine due to its rapid onset, long duration (eight to 12 hours) and its vasoconstrictive effect, which may negate the use of an epinephrine-local anesthetic agent combination.
Ricardo and Lipner recently explored the myth of epinephrine use in nail surgery.2 According to the authors, epinephrine is safe but is not necessary for most nail procedures when using a tourniquet. Since the nail unit is highly vascular and procedures are usually in the outpatient setting, a bloodless field is desirable. This is often achievable with application of a digital tourniquet following local anesthesia injection. While the benefits of using epinephrine in a local anesthetic include hemostasis, prolonged anesthesia and reduced need for a tourniquet, there are controversies in the literature regarding digital use of epinephrine as a potential cause of ischemia and necrosis.2
In a prospective study of finger cases injected with lidocaine or bupivacaine and epinephrine (1:100,000), there was no skin necrosis or tissue loss.3 However, evidence does support avoidance of epinephrine in patients with a history of digital gangrene, Raynaud’s phenomenon or atherosclerosis.2 In a retrospective study of Mohs digital surgery cases utilizing lidocaine with epinephrine, patients with comorbidities such as hypertension, type 2 diabetes and those on anticoagulant therapy had no adverse events.4 As always, prudent clinical judgment is advisable on a per patient basis when choosing to use or avoid epinephrine for a digital block.
Essential Keys To The Diagnostic Workup
Ingrown nail surgery is the most common nail procedure clinicians perform in the office.5 Painful ingrown nails present as painful onychocryptosis or incurvation of the lateral edge of the nail plate with or without paronychia (lateral nail fold edema, redness or drainage). This condition is also more common in teenagers and young adults. It is commonly accepted that the nail border edge, often in the form of a spicule, invades the lateral nail fold and creates an inflammatory response.6 Ingrown toenails most often occur in the hallux and are usually due to a combination of poor nail trimming, shoe gear pressure, the presence of nail disease like onychomycosis and biomechanical considerations.6 When focal erythema, swelling, drainage, granulation tissue and/ or hypertrophy of the periungual tissue are present, the ingrown nail becomes a paronychia.
One theory with ingrown toenails is that the nail itself is the issue (as one would see with pincer nails) whereas another prevailing theory suggests the soft tissue surrounding the nail is the causative factor. Patients with diabetes tend to have a higher rate of ingrown nails in comparison with those who do not have diabetes.6 Ingrown nails are a possible adverse event of using medications such as indinavir (Crixivan, Merck), retinoids, docetaxel, cyclosporine, oral terbinafine and topical efinaconazole (Jublia, Ortho Dermatologics). Whatever the prevailing source, ingrown nails may cause significant quality of life issues due to the associated pain affecting gait and shoe wear, which can affect sports, school and work.
Before delving into conservative and surgical treatment options, it is important to determine if there is an underlying biomechanical cause for an ingrown nail 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 self-inflicted “bathroom surgery”) and the outcome of said procedures should also 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. Nails should be free of nail polish or other adornments on the affected foot. When it comes to ingrown toenails, the physician should note the level of pain as well as the presence of infection, erythema, edema, granulation tissue and drainage.
Differential diagnoses of an ingrown toenail, especially one with granulation tissue, include: pyogenic granuloma, amelanotic melanoma, basal cell carcinoma, squamous cell carcinoma and subungual exostosis. In cases in which a nail procedure with removal of granulation tissue occurs and “granulation tissue” is again present at a postoperative visit, one should consider a skin tumor diagnosis and perform biopsy of the tissue.
Conservative Therapy Pearls For Ingrown Nails
Conservative therapies may be useful in certain situations in which there is vascular compromise, issues surrounding an office-based surgical procedure, someone for whom a procedure is not advisable or as temporary solutions until one performs a surgical procedure.
Suggestion of a wider toe box or an open-toed shoe may be useful for some patients. Treatment of an underlying cause such as onychomycosis or hyperhidrosis is also important. One should educate patients on trimming of the nail straight across and not curving in the nail borders, which often perpetuates ingrown nails both iatrogenically and organically.6 A conservative option, the “slant back” procedure of trimming the nail edge as far proximally as possible, which podiatrists often do in the office, offers temporary pain relief but necessitates periodic visits to continue the brief respite it provides.
Other modalities include gutter splinting, taping the lateral nail fold and massaging of the nail fold. These methods require patience and time on the patient’s part. The gutter splint technique involves lengthwise splitting of a plastic intravenous tube and inserting it under local anesthesia as far proximally as possible, thus creating a barrier between the nail spicule and the lateral nail fold.6 Then one would secure the tubing and leave it on the nail for three to four weeks in order to allow the nail spicule to grow distally without injuring the surrounding skin. A similar method of inserting cotton wisps under the nail plate edge is an older approach but may be useful for those who cannot have nail surgery.
Taping of the skin surrounding the painful nail corner with a Band-Aid or another type of medical tape encourages the skin and nail to grow away from each other, relieves pressure and allows drainage if present. Placing tape at the corner of the offending nail and then pulling it proximally and plantarly on the affected digit often provides instant relief, but there are currently no randomized, controlled studies of this technique, which requires daily use for several months to have a long-term effect.
Examining The Role Of Partial Nail Avulsions
For those patients who have failed conservative therapy or have a presentation that is too severe for a non-surgical intervention, a partial nail avulsion of the affected nail edge is indicated.
The purpose of this procedure is to decrease the width of the nail plate at the offending border to relieve pain and pressure. One can certainly extend this procedure to include removal/destruction of the nail matrix, either surgically or chemically, to cause long-term narrowing of the nail plate. Prior to performing any toenail procedure, it is imperative to obtain patient consent and document risks, benefits and potential consequences of the planned procedure.
A partial nail avulsion is a temporary procedure as the nail matrix is not typically destroyed, thus leading to regrowth of the nail plate in the avulsed area. In regard to the general technique, one swabs the area with 70% alcohol and injects local anesthesia in either a digital block or wing block technique. The surgeon may or may not elect to use a digital tourniquet. If there is granulation tissue present, one may excise this to better visualize the nail plate, discarding or sending this tissue for pathology depending on the history and clinical presentation.
Some surgeons utilize a Freer elevator to lyse the nail plate from the nail bed, distal to proximal, to have a cleaner and easier removal of the nail plate border. This is an ancillary step based on the surgeon’s choice. Then, using an English anvil (nail splitter), small scissors or a nail nipper, one splits the nail plate border from the rest of the nail from the hyponychium to the nail matrix (under the proximal nail fold), being careful not to damage the nail bed or the proximal nail fold. The clinician subsequently employs a straight hemostat to remove the sliver of nail plate. One may use a curette to assess if any nail plate remains under the proximal nail fold and also clean the tissue of any debris.5
While there are many variations of performing a partial nail avulsion, originally described by Ross, adjunctive interventions are the mainstay to this day, based on surgeon preference and training.7
What The Literature Reveals About The Chemical Matrixectomy
Given that the recurrence rate for a simple partial nail avulsion is approximately 70 percent, one can perform a chemical matrixectomy after a partial nail avulsion, utilizing either phenol or sodium hydroxide in the area of the nail matrix at the removed offending nail border.6 In 1945, Boll was the first to describe the use of phenol following a partial nail avulsion.8 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 show that the amount of phenol recovered (i.e. removal of phenol) when one irrigates the area with either polyhexanide biguanide (PHMB) or sterile saline solution is greater than the amount of phenol recovered after irrigation with alcohol.9,10 Ultimately, alcohol and the other solutions utilized in these studies do not neutralize phenol. They simply serve to dilute it and aid in its removal.10
Researchers describe 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.11 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.11
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 number of applications that will effectively destroy matrix cells. Boberg and team utilized nail specimens obtained from patients who had ingrown toenails.8 In this study, 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 remained intact, which would imply that recurrence is likely to occur. 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.8
However, when Becerro de Bengoa Vallejo and coworkers examined the application of 88% phenol to fresh cadaveric hallux nail samples, they found that a one-minute application left the basal layer of the epithelium intact.12 After studying up to six minutes of application, researchers determined that four minutes of application destroyed the nail matrix.
The study by Boberg and colleagues supports the wide podiatric use of prepackaged, phenol-soaked cotton tip applicators (containing 89% phenol) that are intended for a single dose, one-minute application.8 Ultimately, further studies not only need to determine the amount of exposure required to destroy nail matrix cells but should elucidate the overall rate of recurrence and recurrence in the presence of infection as well.
Comparing Phenol Matrixectomy To Sodium Hydroxide: What You Should Know
In my clinical experience, phenolization of the nail matrix has side effects including post-operative drainage for days to weeks and pain. Two studies have examined the use of sodium hydroxide and its potential side effects. Bostanci and colleagues described a case study of three patients who developed allodynia, nail dystrophy and hyperalgesia after having a 10% sodium hydroxide chemical matrixectomy.13 There are limited reports in the literature of post-operative complications from the use of sodium hydroxide. However, one should not consider these complications to be rare until a larger study or case series demonstrates otherwise.
Recently, Chander and team compared 88% phenol to 10% sodium hydroxide following partial nail avulsion.14 Due to phenol causing coagulation necrosis versus the liquefactive 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 a shorter recovery time than those in the study by Bostanci and coworkers.13,14 However, Chander and colleagues used a one-minute application time of sodium hydroxide in comparison to a three-minute application time, which could lessen side effects.14
Regarding specific patient populations, chemical matrixectomies are still indicated for patients with well-controlled diabetes and patients on anticoagulant therapy.15 Any patient undergoing a partial nail avulsion with a chemical matrixectomy should receive education on home care of the wound since phenol may cause a burn to the surrounding skin. Various topical medications and dressings are available for the physician to utilize in office, and recommend to the patient for home care.
When There Is Inflammation At The Proximal Nail Fold: A Closer Look At Retronychia
If you encounter a patient with edema, erythema, granulation tissue, pain and/or drainage at the proximal nail fold who has failed oral antibiotic therapy, you may be dealing with retronychia. A clinical diagnosis, retronychia is the ingrowing of the
base of the nail plate into the ventral aspect of the proximal nail fold.16 Clinicians often misdiagnose retronychia as a fungal infection or a paronychia warranting anti-infective therapy. Neither antifungal agents nor antibiotics will resolve this nail issue.
Patients may complain their nail is swollen at the base of the nail or has not grown, and they deny occult trauma. Although the pathogenesis is not entirely known, the prevailing thought is that repeated microtrauma causes disruption of the longitudinal nail growth and forces the new nail plate to grow under the older nail plate, and become adhered to one another. Often affecting the great toenail, retronychia does not allow the nail to proceed distally, which results in swelling and pain at the proximal nail fold. This condition warrants a total nail avulsion, which is curative. Following this procedure, recurrence of retronychia is rare.
Ingrown nail surgery is an incredibly common office-based procedure. After assessing if the nail or the skin folds are the basic source, it is important for the physician to look at other causative factors such as hyperhidrosis, biomechanics or medications prior to performing the procedure. Conservative care may be useful for mild presentations. However, for many patients, an office-based surgical procedure to remove the offending nail border is necessary. One can follow this with a chemical matrixectomy, which has a lower recurrence rate than a simple partial nail avulsion alone and, in certain situations, a surgical matrixectomy. For a patient presenting with an “ingrown” nail border at the proximal nail fold, the clinician must consider a diagnosis of retronychia, which one can alleviate with a total nail avulsion.
Dr. Vlahovic is a Clinical Professor in the Department of Podiatric Medicine at the Temple University School of Podiatric Medicine in Philadelphia.
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