Sacrococcygeal pilonidal sinus disease is a chronic recurrent subcutaneous tissue inflammation in the natal cleft and, in general, affects young men with a prevalence of approximately 9% among soldiers.1 The disease usually presents as a chronically discharging sinus tract or an abscess. Regardless of the mode of presentation, the disease causes significant morbidity by disturbing the quality of life. However, the treatment of pilonidal disease has been the subject of debate for many years.2 The ideal remedy would be a quick cure that allowed patients to return rapidly to normal activity, with minimal morbidity and low risk of complications.
To date, the treatment modalities for pilonidal disease are variable, argumentative, and problematic. These therapy options may sometimes be responsible for significant morbidity and thereby loss of productive hours and cost to health insurance systems.3,4 Thus, the final decision on the treatment of choice is sometimes complicated for both the patient and the surgeon. For these reasons, much interest and effort have been focused on exploring and identifying an ideal method. Surgical treatments are focused on mainly excision with open healing or excision with midline or off-midline closure procedures. Still, surgical treatments have some disadvantages such as long healing times and high recurrence levels. Phenolization is an alternative treatment modality.5 This method can be performed under local anesthesia in outpatient conditions. Many case series using the application of phenol have been published with a success rate varying between 60% and 100%.5,6 However, there has been no randomized, prospective study that includes long-term results comparing surgical and phenol treatment. The aim of the study is to compare phenol injection vs an excision with open healing technique in a prospective randomized trial.
This was a prospective randomized study conducted at the Departments of Surgery, Ankara University Medical School and Ufuk University Medical School, Ankara, Turkey. The study protocol was approved by the Ethics Committee of Ankara University Medical School (Ethics Committee no: 09-283-12), and written informed consent was obtained from the participants. This study protocol was constructed according to the CONSORT guidelines.7
The trial was registered at www.anzctr.org.au (ACTRN12612000868886).
Participants and Eligibility Criteria
Patients aged 18 years and older who were diagnosed with primary or recurrent chronic pilonidal sinus disease between April 2011 and September 2015 were considered eligible. Patients who had chronic symptoms of sacrococcygeal pilonidal sinus disease were included. Patients were excluded from the study if they: 1) had acute pilonidal sinus abscess or induration, 2) had abscess drainage within 2 months, 3) had immunosuppressive and/or coagulation disorders, 4) were pregnant or lactating, or 5) had other acute surgical diseases.
The sample size required for the study was calculated based on the primary outcome variable, that is, complete wound healing time. Group sample sizes of 68 and 68 achieve 80% power to detect a difference of 5 days between the 2 groups with standard deviations of 10 and 10 with a significance level of 0.05 using a 2-sided Mann-Whitney U test. We enrolled 147 patients (more than the required sample size) to cover any patients lost to follow-up.
Patients who were eligible and willing to participate in the study were randomly assigned to receive either phenol treatment or surgical treatment. We used block randomization to ensure an equal number of patients in each group. A medical resident from each center, who was blinded to the research protocol and was not otherwise involved in the trial, operated the random number program and assigned treatments.
Medical and Demographic History
For each patient participating in the study, a detailed history was taken, and a physical examination was conducted. The following demographic and clinical data were recorded: age, sex, body mass index, education level, employment status, smoking, alcohol usage, family history of pilonidal disease, duration of symptoms, concurrent disease (diabetes mellitus, hypertension, atherosclerosis, renal failure, chronic obstructive lung disease, autoimmune disorders), previous surgery (other than pilonidal sinus surgery), drug usage for chronic illness, duration of the operation, hygienic behaviors and working conditions. Daily standing and sitting time were evaluated during the work period as hours per day. If the patient either sat or stood less than 30 minutes during the working period, then it was recorded as 0 hours per day. In addition, the number of sinuses, direction of the sinuses, and the widest diameter of the sinus were recorded.
The phenol application was performed following local anesthesia with Lidocain (Jetokain, Adeka İlaç Sanayii, İstanbul, Turkey). If the sinus opening was less than 3 mm in diameter, then the opening was enlarged by use of a mosquito clamp (BH-109 Aesculap, Aescuplap Werke AG, Tutlingen, Germany). If at least one of the sinus openings was 3 mm or more in diameter, we did not perform this enlargement. Following determination of the direction of the sinus, the hair was removed with use of the same clamp. If the sinus abscess had been drained previously, then the drainage opening was usually large enough to remove the hair. After removal of the hair, a swab or large piece of cotton wool was used to protect the anus, while the rest of the area was liberally coated with nitrofurantoin ointment (Furacin Soluble Dressing Pomad, Eczacibaşi İlaç San ve Tic A.Ş., İstanbul, Turkey) to protect the skin against possible contact with phenol. The crystallized phenol was put into the sinus with the aid of the same clamp. The crystallized phenol melted quickly at body temperature and filled the sinus. The phenol was left in situ for approximately 2 minutes and then expressed by pressure. The excess was mopped away with the debris. This maneuver was repeated 2 or 3 times, depending on the width of the sinus. Finally, the wound was closed with a gauze pack. All procedures were performed with the patient in a prone position. Necrotic debris was removed from the cavity after 24 hours. Afterward, there was no longer need for regular dressings, and ordinary sanitary napkins over the wound were enough to prevent soiling the clothes. If the patient’s wound had no leakage at the follow-up periods, then no further procedure was done. If wound leakage was observed, then the same method described above was repeated.
Although phenol is a toxic substance, careful local application is safe, and no major morbidity has been reported since its first clinical local application to sacrococcygeal pilonidal disease in 1964.8 However, strict precautions were necessary throughout the procedure, especially in the handling of the phenol. Because it is a necrotizing material and causes burns on mucosa and skin, we were careful to avoid contact with the skin or eyes.9–12 Moreover, inhalation and swallowing may cause serious life-threatening conditions.13
Excision With Open Healing Surgery
The surgical procedure was performed under spinal anesthesia. Patients were positioned in the prone jackknife position, and the buttocks were drawn to the side by an adhesive tape. Methylene blue was injected to define the exact borders of the disease, if required. An elliptical incision of the skin was made around the pilonidal sinus. Surgical diathermy was used for further complete excision of the sinus or cyst, if necessary, up to the level of the fasia. Following the excision, the open healing technique was performed with marsupialization, where appropriate. After hemostasis, the wound was covered with sterile gauze.
Patients who had phenol treatment were discharged after the procedure, whereas patients in the surgery group were discharged 24 hours after the operation.
After both interventions, patients were informed to be careful in keeping the area clean and free from hair. Personal hygiene of the area was encouraged by frequent bathing and by not rubbing toward the wound after bowel movements. All patients used depilation cream from the waist to midthigh posteriorly and kept this area clean without hair during the treatment period.
The primary end point of the study was the time to complete wound healing. Secondary end points were the visual analog scale score for pain, painkiller intake, time to resume daily activities, and the recurrence rate.
Patients were reviewed at 12, 24, and 48 hours after the procedure. The procedure time, length of hospital stay, pain-free mobilization time (self-defined), pain-free defecation time (self-defined), dressing time, healing time, and postoperative complications were recorded. The visual analog scale was used to score the pain levels (1-10) of patients at 12, 24, and 48 hours after the procedure. Painkiller intake was also recorded at the same times. All patients used the same painkiller (Diclofenac sodium-Voltaren, Novartis Sağlik, Gida ve Tarim Ürünleri San. Tic. A.Ş., Turkey), and it was given when requested by the patient, provided that it was within the safe dose limits.
The first follow-up at 3 weeks postoperation was done by interview and clinical examination using a standardized form. The second follow-up was done at 6 weeks, and subsequent follow-ups were done at the 3rd, 6th, 12th, 24th, 36th, and 48th postoperative months. In addition, patients were asked to contact the research resident at any time during follow-up if they were concerned about their wound. Follow-up examinations within the first 12 months were done at the outpatient clinic. Beyond 12 months, long-term follow-up was monitored either by direct review at the outpatient clinic or by phone calls every year to check for recurrences.
Dressing time was defined when the wound did not need to be covered by gauze by the patient’s preference. Healing time was recorded when the wound was completely closed with epitheliazation and without any discharge or symptoms such as pain, swelling, or cellulitis. Recurrence of disease was defined as detection of new orifices or discharge from the wound after complete healing.
The Short Form-36 Health Survey (SF-36) was used to evaluate the quality of life for every patient before and 3 weeks after the procedure.14 The Nottingham Health Profile (NHP) questionnaire was used to provide a brief indication of a patient’s perceived emotional, social, and physical health problems before and 3 weeks after the procedure.15
The Shapiro-Wilk test was used to assess normality assumption for continuous variables. The difference between 2 groups for continuous variables was evaluated by the Student t test. The Mann-Whitney U test was used to test the difference between 2 groups in terms of ordinal or nonnormally distributed continuous variables. The differences between groups in terms of categorical variables were compared by using the χ2 test or Fisher exact test, where appropriate. The Wilcoxon signed rank test was used to evaluate the difference between pre- and postoperation measurements. The recurrence-free estimations were performed by using the Kaplan-Meier algorithm, and the comparison between groups was evaluated with the log-rank test. A p value less than 0.05 was considered significant.
Between April 2011 and September 2015, 183 patients were evaluated for eligibility at the Departments of Surgery, Ankara & Ufuk University, and 36 were excluded. A total of 147 gave their informed consent and were recruited for the study. Patients were randomly assigned to the 2 groups: phenol treatment (n = 74) or surgical treatment (n = 73). The number of patients lost to follow-up was 3 in each group. One patient in the phenol group was excluded from the analysis because of recurrence at the 18th month, and he withdrew. Thus, the number of patients that could be analyzed included 140 patients; each group had 70 patients. An overview of the study methodology is shown in the CONSORT diagram in Figure 1.
Demographic and Clinical Characteristics
Both groups were comparable regarding baseline data except that daily sitting time was significantly higher in the phenol group, whereas daily standing time was significantly higher in the surgery group (Table 1). The duration of symptoms, number of sinus orifices, the widest diameter of sinus orifice, and the direction of sinuses was also comparable; however, previous abscess drainage was significantly higher in the surgery group (p = 0.007; Table 2).
The short-term results are shown in Table 3. Compared with the surgery group, the phenol group had significantly lower procedure time, length of hospital stay, pain-free mobilization time, pain-free defecation time, visual analog scale pain scores at 12, 24, and 48 hours, as well as the amount of pain killer intake at 24 and 48 hours and at the first week postoperatively (p ≤ 0.008, for each).
The long-term follow-up revealed significant differences in favor of phenol treatment as shown in Table 4. The length of surgical dressing time and the healing time were significantly shorter in the phenol treatment group (p < 0.001, for each).
The overall complication rate was comparable. Four patients had abscesses in the first week following phenol application, which were treated by oral and topical antibiotics. During the follow-up, 2 of these 4 patients had recurrences.
In addition, 2 patients in the phenol group had intergluteal maceration, which was treated conservatively. Eight patients underwent another phenol application because of ongoing drainage at the third week, 4 of whom had recurrences. In the surgery group, 3 patients had headache, nausea, and vomiting because of the spinal anesthesia and were treated with symptomatic therapy. One additional patient in the surgery group had bleeding, which was managed without reoperation.
The proportion of patients healed at 3 weeks, 6 weeks, and 3 months is shown in Table 5. At 6 weeks after surgery, all patients had healed in the phenol group, whereas 78.6% had healed in the surgery group.
In our study, 85% of cases had a follow-up of more than 24 months. In addition, the mean recurrence-free time was 45.8 ± 1.6 months for the phenol group and 47.8 ± 1.4 months for the surgery group. The cumulative recurrence-free proportions for the first, second, third, and fourth years were 92.9%, 91.3%, 80.7%, and 77.2% in the phenol group, and 97.1%, 91.2%, 89.6%, and 85.7% in the surgery group (p = 0.28) (Figure 2). Recurrence was identified in 13 patients (18.6%) for the phenol group and 9 patients (12.9%) for the surgery group (p = 0.35) (Table 4). History of previous abscess drainage was documented in 18 patients in the surgery group, 2 of whom had recurrences, and 6 patients in the phenol group, 3 of whom had recurrences (p = 0.08). Also, there was no significant difference between groups in recurrence proportions in patients without abscess history (p = 0.797). In the phenol group, the recurrence rate in patients with less than or equal to 3 sinus orifices was 15.0%, whereas it was 40.0% for >3 (p = 0.08). In the surgery group, the recurrence rate was 13.1% and 11.1% (p = 1.00). A single phenol application had a success rate of 85.7%. Only 8 patients required second phenol injection at the third week, 4 of whom had recurrences during the long-term follow-up.
Within-group and between-groups comparisons for SF-36 and NHP are shown in Tables 6 and 7. Both measurements were better in the phenol application group. In particular, improvements in the NHP scores for pain, physical mobility, sleep, and social isolation were significantly better in the phenol group (Table 7).
Surgical treatment of pilonidal sinus sometimes may be responsible for significant morbidity in an otherwise young healthy population, resulting in an important socioeconomic burden. Therefore, its management has increasingly become less invasive and less aggressive. The best method should be simple, cause minimal pain, require a short or no hospital stay and minimal wound care, allow rapid return to work and normal activity, not significantly alter the quality of life, have a low recurrence rate, and be cost-effective.16 So far, the ideal method of treatment is still missing; nevertheless, surgeons prefer minimally invasive therapies more often where appropriate. Phenol injection almost covers each theme for an ideal treatment option.
The present study compared crystallized phenol injection versus an excision with open healing technique in a prospective trial in the surgical management of sacrococcygeal pilonidal sinus disease. Thus far, no randomized controlled trial has been conducted to investigate the effectiveness of crystallized phenol, especially including long-term results. Although the recurrence rate is low in off-midline in comparison with midline closure techniques,17 excision and open healing is routinely used in our practice. Moreover, open healing of pilonidal sinus is associated with a 58% lower risk of recurrence than primary midline closure in a meta-analysis.17 Therefore, we decided to compare phenol injection with the open healing technique. The primary end point of this study was time to complete wound healing after surgery, and that was significantly less in the phenol injection group. Our result of 16.2 ± 8.7 days for wound healing following phenol application is slightly less than 20 ± 14 days in the literature (results of 831 patients in previous publications5), and significantly less than the excision with open healing method (40.1 ± 9.7 days in our study and between 41 and 91 days in previous randomized controlled trials18–22). Moreover, the present study also documented significantly improved outcomes following phenol application regarding the operation time, visual analog scale scores for pain, the amount of painkiller intake, time to resume daily activities, the length of hospital stay, the duration of the need for surgical dressing, and the generic health status as measured by NHP. In addition, quality-of-life assessment by SF-36 revealed better but not significant results as well. Similarly, a recent randomized trial revealed a significant difference in quality of life in favor of the phenol treatment in comparison with primary closure.23
The promising results of this study may be taken as a treatment recommendation for this common disabling condition. There have been many case series about phenol application in the literature since 1964 with a success rate (ie, no recurrence) between 60% and 100% with a follow-up between 8 months and 8 years.5,6,8,9 Note that our definition of healing is complete skin epithelialization together with symptomatic relief. In our study, cumulative recurrence-free proportions for the first, second, third, and fourth year revealed no difference between phenol application and surgery. Recurrences are generally reported in the first year of the phenol treatment.5,6,9 However, the mean time period to detect recurrence was 21.5 ± 12.1 months in our study. This is important when reviewing trials in the literature with short follow-up periods, because the follow-up may not be long enough to capture true recurrence rates.
Previous randomized trials reveal a recurrence rate between 0% and 13% following excision with open healing, and it was 12.8% in the present study.18–22 It has previously been shown that the recurrence rates increase with the number of sinus orifices.10 Kaymakcioglu et al10 reported a 4.7% recurrence rate in less than 3 sinus orifices compared with 37.5% in more than 4 sinus orifices in a 24-month follow-up period following phenol application. Similarly, healing times are reported to be shorter if there are fewer than 3 orifices.24 The mean number of sinus orifices was similar between the groups in the present study. However, the recurrence rate was 15% if there were ≤3 orifices, whereas it was 40% for >3 orifices in the phenol group, suggesting that surgery might be a better option for the latter group of patients.
Better results are achieved when crystallized phenol is used compared with 80% liquid phenol.25 Silver nitrate and 80% to 90% alcohol are alternative agents for nonoperative management as well. These may also be used as sclerosing agents, but little information is available regarding their outcomes in the literature. Interestingly, the success rates for phenol application are similar to the various surgical management options.
Local complications were documented in both groups in our study. Four patients had abscesses in the first week following the phenol application, and all were treated conservatively. Abscess and cellulitis are the most common postoperative complications documented following phenol treatment, occurring in about 8.7% cases.5 The main reason for this might be the leakage of phenol into the adjacent tissues, opening up a false route during the initial probing or blockage of the sinus tract with debris.9–12 In addition, we recorded 2 patients with superficial skin maceration due to phenol destruction. Another disadvantage of phenol treatment is its requirement for repetitive applications. Repeat applications have been required for about 35.5% of patients, some at 1 week afterward and some at 3 weeks.26 Nevertheless, a single application of crystalized phenol has a success rate between 56% and 83% in the literature, and it was 85.7% in our study.5,27,28 This treatment option may still be better than surgical alternatives. Reapplication of phenol was necessary in 8 patients in our study because of the ongoing drainage at the third week, and unfortunately 4 of them had recurrences. On the other hand, 3 patients in the surgery group had morbidity due to spinal anesthesia and were treated with symptomatic therapy. One patient had a bleeding problem postoperatively, which was managed without reoperation. Other studies have found bleeding in up to 2.8% of the cases after surgery.29–31
The current study has some limitations. First, the study could not be blinded to both patients and the surgeon. Only the research assistant was blind for the outcome variables. Moreover, 3 patients in each group were lost to follow-up. Second, there was significantly higher number of patients in the surgery group with history of abscess drainage compared with the phenol group despite randomization. However, this did not affect the recurrence rates in both groups. Third, some of the patients were unable to attend the clinic visit, and the long-term follow-up phone calls might have missed or overdiagnosed some recurrences. However, the patients were asked to contact the research resident at any time during follow-up if they were concerned about their wound. Nevertheless, it is the first randomized study on this topic.
Our prospective, randomized study assessed the effects of phenol injection in the surgical management of sacrococcygeal pilonidal sinus disease. Based on the results, we conclude that phenol injection is as effective as the excision with open healing technique.
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Keywords:© 2017 The American Society of Colon and Rectal Surgeons
Crystallized phenol injection; Excision; Open healing; Pilonidal sinus; Quality of life