Ingrown toenails are one of the most common presenting pedal foot maladies with an estimated 20 percent of those who present seeking foot care for this problem.1,2 Chemical matrixectomy is one of the most common surgical procedures podiatrists perform. Although the technique for the matrixectomy procedure is fairly simple and straightforward, there are many modifications to the procedure and there are controversial issues including the use of adjunctive antibiotics and postoperative care. In order to understand the evolution of the procedure, one must start with the initial description of this procedure in the literature. In 1945, Otto Boll was the first to discuss the use of phenol in treating ingrown toenails. He described removing the nail edge and swabbing the root with pure phenol for 30 seconds, and subsequently pouring alcohol on the wound. In 1953, Gottlieb described removing the entire nail plate and applying phenol for 30 seconds. In 1956, Nyman reported using two small cotton-tipped applicators to apply phenol for 30 to 40 seconds each. Suppan and Ritchlin described applying phenol for two minutes and following it with a three-minute application of alcohol. In 1965, Cooper reported that alcohol lavage was painful and the length of phenol application made no significant difference regarding healing. As we know, the phenol matrixectomy procedure has been referred to as a phenol and alcohol matrixectomy. The recommendation for using alcohol comes from the fact that phenol is soluble in alcohol and alcohol will accordingly lavage the excess phenol from the nail groove. The initial belief was that alcohol would minimize the chemical burn that is created by applying phenol. However, Greene believed that using alcohol can create more postoperative drainage and inflammation, leading to prolonged healing time. In reviewing the history of the phenol matrixectomy, there is no scientific evidence to suggest that using alcohol after phenol application will decrease the healing time. At this time, using alcohol to wash out the phenol is purely anecdotal. Furthermore, the decision to use two or three applications of phenol for 30 or more seconds is purely based on the practitioner’s experience.
Pertinent Treatment Tips
That said, let us take a closer look at the technique we teach in the Department of Medicine at the California School of Podiatric Medicine. Anesthetize the hallux with local infiltration of 1% plain xylocaine in a standard ring block fashion. Then swab the nail with isopropyl alcohol. One would exsanguinate the digit with a 1/2 inch Penrose drain wrapping from the apex to the base of the toe in a winding, overlapping fashion. Secure it at the base of the toe with a hemostat. Free the offending nail border from its soft tissue attachments with an elevator and cut it with an English anvil nail splitter and a #62 or #64 blade. Proceed to remove the nail plate with a hemostat. Excise any exuberant granulation tissue present along the periungual area. Using narrow cotton swabs, proceed to apply three applications of 89% phenol to the nail matrix for approximately 30 seconds each. Take care to hold the swabs at a 45-degree angle to the skin in order to avoid exposure of the nail bed to the phenol. Release the tourniquet. Then dress the nail groove with plain 2 X 2 inch gauze and a self-adherent bandage. In regard to the follow-up visit, the patient should return four to seven days later. The patient removes the dressing two to three days after the procedure at home. Instruct patients to cleanse the nail bed in the shower or bath per their normal routine and to apply a band-aid over the toe. The postoperative care will vary from one clinician to another. In my experience, obtaining 100 percent hemostasis is one of the most important steps of the phenol matrixectomy procedure when it comes to reducing ingrown nail recurrence. When one removes the cotton swab from the nail matrix/nail groove, it should be as white as it was when it was first dipped in phenol. In other words, if the cotton swab is dark or black, the hemostasis was suboptimal and it may increase the rate of recurrence.
Should You Use Adjunctive Oral Antibiotics?
The use of oral antibiotics as an adjunct to treating ingrown toenails is a widespread practice and clinicians often use these antibiotics as an essential component in the treatment course.3,4 However, the necessity of oral antibiotics remains controversial. Some physicians feel that instituting oral antibiotics before performing a phenol matrixectomy or at the time of the procedure reduces the risk of developing further infection.5 However, other investigators have indicated that once the clinician removes the offending nail, the localized infection will resolve without the need for antimicrobial agents.6,7 Some practitioners typically ask the question: If it cannot hurt to utilize an oral antibiotic, why not prescribe it? The answer to this question is very simple. We are now faced with a very serious problem of antibiotic resistance. We are dealing with the development of life-threatening microorganisms which, in part, are the direct result of indiscriminate and prolonged use of antibiotics. As practitioners, we should adhere to strict indications for antibiotic use. With this in mind, a prospective study evaluated the use of oral cephalexin as adjunctive therapy in treating a paronychia secondary to an ingrown toenail. The purpose of this study was to determine prospectively whether oral antibiotic therapy is beneficial in the treatment of infected ingrown toenails by phenol matrixectomy.8 During a one-year period, we enrolled 154 patients who ranged between the ages of 10 to 60. All subjects presented with a locally infected, ingrown hallux nail. We defined infected, ingrown toenails as those with nail borders exhibiting paronychia, granulation tissue, edema and exudates. For the purposes of the study, we excluded patients with immunocompromised states (chronic steroid use, diabetes mellitus, collagen vascular disease or HIV), those with peripheral vascular disease and patients who had cellulitis proximal to the hallux interphalangeal joint. Each patient was randomly assigned to one of three groups. Group one patients (53 patients) received a one-week course of oral antibiotics (cephalexin) and a simultaneous phenol matrixectomy at the initial presentation. Group two patients (51 patients) received a one-week course of oral antibiotics (cephalexin) at the initial presentation and underwent a phenol matrixectomy one week later. Group three patients (50 patients) received a phenol matrixectomy at the initial presentation without antibiotic therapy. We chose to use 500 mg of cephalexin four times daily for this study based on its efficacy against coagulase negative staphylococcal species, specifically Staphylococcus epidermidis, the most commonly cultured pathogen found in infected, ingrown toenails.9 All groups were age matched with an overall mean age of 20.67 + 8.6 years (mean + SD). Two patients in group three developed post-procedure infections. However, there was not a significant difference in the prevalence of post-procedure infections between groups. Both patients received oral antibiotics and healed uneventfully within two weeks. There were no post-procedure infections in groups one and two. The results of this study suggested that oral antibiotics do not reduce postoperative infection rates in the treatment of ingrown toenails. In fact, the group that did not receive cephalexin did not have a statistically significant higher rate of infection than groups one and two, which received oral cephalexin. The study results support the notion that oral antibiotics are not indicated in treating paronychias secondary to an ingrown toenail unless cellulitis proximal to the interphalangeal joint is present. One of the questions this study does not address is the recurrence rate. The recurrence rate after phenol matrixectomy ranges from 2 to 50 percent in the literature. We recently finished a follow-up retrospective study that evaluated the recurrence rate after matrixectomies. This study evaluated 100 patients who underwent phenol matrixectomies for paronychias secondary to an ingrown toenail one year after the procedure. None of the patients received oral antibiotics. The recurrence rate after phenol matrixectomy was less than 3 percent. None of the patients developed a post-op infection. These results further support the safety and efficacy of performing phenol matrixectomy on patients with locally infected (paronychia), ingrown toenails without using adjunctive oral antibiotics. This study is being submitted for publication. Many podiatric physicians currently prescribe oral antibiotics for locally infected ingrown nails on the basis of their own opinions. While it is appropriate to base this decision on one’s own clinical experience, it is considered a lower level of evidence based care when compared to treatment guidelines obtained from the results of a prospective study.
Should You Perform Matrixectomies On Patients With Diabetes?
The above studies focused on phenol matrixectomies in non-diabetic patients. One question that has been circulating in podiatric practices is whether it is safe to perform phenol matrixectomies in patients with diabetes. The scare has revolved around phenol causing a chemical burn that will overwhelm the healing ability of a patient with diabetes and lead to non-healing and gangrene. For those of us who are uncomfortable performing phenol matrixectomy in patients with diabetes, there is now scientific evidence. Giacalone reviewed 57 patients with diabetes who underwent phenol matrixectomies. The results of his study showed no complications and a 5 percent regrowth rate. The decision of whether to perform the phenol matrixectomy should be based solely on the amount of arterial perfusion to the toe. Diabetes is not a direct risk factor for non-healing in patients undergoing phenol matrixectomy. It is the arterial disease that will determine whether the patient has the potential to heal.
Post-Op Care: Should Patients Soak The Foot?
When it comes to postoperative care after a phenol matrixectomy, I have found that clinicians commonly tell patients to soak the foot in water with or without Epsom salt. This area of postoperative care may have the most variability among practitioners. There are many topical modalities one may employ for postoperative care. These include but are not limited to wound healing gels, calcium alginates and topical antibiotics. When I was a student, I learned that soaking was the way to go. During my residency, one of my attending physicians instructed me not to have the patient soak the toe. This variation in postoperative care made me question the necessity of soaking. Why do we tell our patients to soak? Perhaps this stems from the basic notion that wounds heal best in a moist environment. Soaking the toe in warm water with or without Epsom salt or other substances may be beneficial in keeping the wound moist and promoting drainage. Podiatrists typically ask the patient to soak once or twice a day for one to two weeks. For the past seven years in my practice, I have been instructing my patients not to soak their toe. In fact, I instruct my patients to keep the dressing dry for two to three days before they take it off and apply a band-aid. I have found that keeping the dressing dry allows the matrixectomy site to heal and dry faster when compared to soaking. The proponents of soaking state that keeping the dressing dry and in place for two to three days increases the chance of infection as opposed to soaking the toe, which allows the patient to inspect the matrixectomy site on daily basis. We addressed the issue of infection in our prospective study in which we looked at three groups and the use of oral antibiotics. We found no statistically significant evidence of infection in our post-matrixectomy patients who did not receive oral antibtiotcs. A 1998 study by Van Gils, et. al., compared a collagen-alginate wound dressing with daily soaks.10 The results demonstrated that the collagen-alginate dressing was superior to soaking in terms of the healing time. Summarizing the post-op care of a phenol matrixectomy, it is obvious there are many available dressing options including soaking. It is important for the practitioner to know that soaking is not the only option and that there is no evidence based study to support that soaking in any way prevents an infection. In fact, the aforementioned studies have shown that by drying the matrixectomy site, there may be decreased healing time.
While phenol matrixectomy is one of the most common procedures podiatrists perform, there is very little scientific evidence in the literature to support some of the current techniques, indications and postoperative care for phenol matrixectomies. However, in the last several years, there have been several published studies that now provide the practitioner with evidence based guidance. Dr. Reyzelman is the Chairman of the Department of Medicine at the California College of Podiatric Medicine at Samuel Merritt College. He practices privately in San Francisco.
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