An algorithmic proposal for the treatment of pilonidal disease based on outcomes over a 30 year period

Introduction

Pilonidal disease is a debilitating chronic infective and inflammatory condition that affects primarily young people after the age of puberty but before the age of 40 years. An incidence of 26 per 100,000 [1] is usually quoted, although more recent publications have doubled the figure at 48 per 100,000 [2], suggesting a rising incidence. For many this condition causes a significant disruption to their lives, both professionally and socially [3].

There are several treatments described for the treatment of pilonidal disease, which tends to suggest that none are entirely satisfactory from the point of view of curing the condition, with failure of the treatment and recurrence being a sequel to all treatments described. However, treatments are now being well-recognised that have 90% success in treating pilonidal disease with recurrence rates of 10% or less, and these should now be the standard to which treatments should aspire.

The PITSTOP study examined in detail the practice of pilonidal surgery at several centres in the UK and found that treatment failures and the burden of disease are high [4]. They concluded that better outcomes could be obtained by selection according to disease type to stratify the severity of the disease [5].

The severity of the disease makes it necessary to perform excisional procedures in many patients, and these are now known to have a better outcome if the closure is off the midline [6]. Midline excision and either suture or laying open should now be avoided. However, many patients have simple disease with a few midline pits and limited lateral discharging sinuses. These cases can be treated by non-excisional methods such as trephine operation [7], Bascom’s pit-picking procedure [8], endoscopic pilonidal sinus treatment (EPSiT) [9], laser treatment and fibrin glue [10], with satisfactory outcomes and minimal morbidity as has been clearly demonstrated in the PITSTOP study [4]. In spite of this however, all too often, in a one-size-fits-all policy, excisional procedures are done for such cases which, if they fail or recur, often end up with patients being in a worse condition than they were from their original disease, which is considered unacceptable by patients [11]. It is therefore unnecessary and unjustified to subject patients to an excisional procedure for pilonidal disease if it is not required.

Methods

A large cohort of patients treated at two hospitals (St Mark’s Hospital, London, and Queen Alexandra Hospital, Portsmouth) between 1991 and 2021 under the care of one clinician were operated on for pilonidal disease. Their data were collected prospectively after written consent was obtained. Demographic information – age, sex, duration of disease and previous treatment – was collected. The treatment given was recorded, and failure of treatment and recurrence over time were also recorded prospectively. Recurrence was defined as further pilonidal infections or formation of midline pits after initial healing of the wound, requiring further surgery.

Four techniques were offered for the management of pilonidal disease: trephine (Gips procedure), Bascoms pit-picking procedure, Bascom’s cleft closure (cleft lift) and simple laying open of disease. The non-excisional methods were done once only. Patients who developed recurrence after one attempt of a non-excisional procedure were offered a cleft closure as a more definitive intervention.

The Berlin classification proposed by Wysoski in 2017 [12] (and evaluated most recently by the PITSTOP study group [5]) was applied retrospectively to the database at one site and prospectively gathered at the second site by two clinicians. Type 1 had midline pits only, Type 2 had midline pits with secondary openings or abscess cavity, Type 3 had disease outside the navicular area and Type 4 had recurrence after previous surgery with curative intent. Diagrams of the operative findings and techniques for all patients were recorded, and therefore, an accurate application of the classification was possible retrospectively for all patients where it had not been collected at the time. Where contradiction or doubt were encountered over classification, discussions were held between the two clinicians until consensus was reached. This then allowed the stratification of the disease to be done for all patients.

Outcomes were analysed by operative interventions and have been presented elsewhere. Bascom’s operation has a 9.3% recurrence rate [13] and cleft closure (also known as cleft lift) 5.3% [14]. In this study the outcomes were analysed according to the classification, which in turn reflected the severity of the disease.

Continuous variables were expressed as a mean. Non-parametric data were expressed as median and interquartile range. The results were analysed by Chi-square comparing the outcomes from the four types of disease.

Results

An initial 1445 patients were seen during this time period presenting to clinic with pilonidal disease. A total of 1308 patients (1001 male) underwent surgery at the two sites and had documented follow-up. On retrospective review of this cohort, a further 44 patients did not have adequate information to provide a classification, and these were excluded. The mean age of the remaining cohort (n = 1264) was 28 years old with a range between 12 and 84 years old. The mean symptom of duration was 3.6 years (ranging from 2 weeks to 40 years). Almost a quarter (22.7%, n = 297) of the cohort had at least 1 attempted previous curative surgery. Median follow-up of the cohort was 8 months [interquartile range (IQR) 3–13 months]. All patients are asked to get in touch should they get a recurrence, even if they are treated elsewhere.

The operations recorded by classification are shown in Fig. 1. Four techniques were offered for the management of pilonidal disease: trephine (Gips procedure), Bascoms pit-picking procedure, Bascom’s cleft closure and simple laying open of disease. The majority of the patients who had disease classified as Type 1 and 2 had been treated by non-excisional methods (trephine and Bascom’s pit picking), and the majority of patients in Type 3 and 4 were treated by an excisional operation (cleft closure).

Fig. 1.

Operative techniques used for the different classifications

Of patients, 70.5% (n = 891) had disease classified as either Type 1 or Type 2. Of patients with Type 1 or 2 disease, 66% were offered simple non-excisional surgery. In 13% of Type 1 it was not possible to offer this (such as with many pits in the midline) and also in 43.5% of Type 2 (with a secondary opening too far from the pits or a midline pit too large to offer a pit-picking procedure). Of patients, 29.5% (n = 373) had disease classified as Type 3 or Type 4 disease, and the majority were offered cleft closure surgery (90.3%). A few patients in these groups were considered suitable for non-excisional methods (such as those with a single pit low down in the natal cleft).

In the Type 1 group, complications were highest in those undergoing cleft closure (13.9%) compared with 1.8% and 4.5% in patients undergoing trephine group and Bascom’s pit-picking technique. Similar findings were observed in Type 2, where complication rates of 11.1% were observed in those undergoing cleft closure compared with no complications seen in the trephine group and 7.4% in those undergoing Bascom’s pit picking. Of the cleft closure wounds, 60.7% healed primarily with the remainder having a minor breakdown that healed by secondary intention. Overall, procedures failed in 3% and required further surgery.

The recurrence rates, according to classification, are shown in Fig. 2. Overall, recurrence rates were similar across all four classifications and were 6.5% (18/276), 7.5% (46/615), 8.5% (5/59) and 7.0% (22/314) from Types 1–4 respectively. There was no significant difference between these recurrence rates.

Fig. 2.

Recurrence rate according to classification

The results of this analysis (Fig. 3) have allowed us to suggest a treatment algorithm (Fig. 4) for the management of pilonidal disease that is practical and has an acceptable recurrence for all types of disease.

Fig. 3.

Table demonstrating recurrence and complication rates in each classfication type

Fig. 4.

Table of complications recorded (in alphabetical order)

Discussion

Currently, there are a plethora of surgical and non-surgical interventions for pilonidal disease. The results of individual treatments can have good outcomes: Bascom’s pit picking 9% [13] and cleft closure 4% [14]. The PITSTOP study showed that a variety of interventions are used [4], but it is not clear whether clinicians alter their treatment options according to severity of disease or patient preference. A one-size-fits-all approach is used by many, with unnecessary morbidity and recurrence, and clinicians need to have a range of options available. The use of an algorithm can more accurately play a role in the management of a disease by providing a structured and standardised approach to help clinicians and patients in their decision-making. It can improve clinical outcomes by highlighting effective interventions for different types or class of disease. A number of treatment pathway algorithms currently exist in the management of other colorectal diseases [15, 16] and one for pilonidal disease would be of benefit. By following a structured approach, we aim to promote personalised treatment for patients presenting with varying severity of pilonidal disease. This treatment algorithm is based on clinical presentation having reviewed outcomes of hundreds of patients presenting with the disease over the last 30 years.

There have been a few classifications proposed for the stratification of pilonidal disease [5, 12, 14, 17, 18]. This classification has been evaluated in the PITSTOP study [5] and has been shown to be reproducible and reliable. This is the first algorithm offered on the basis of this classification.

We have demonstrated that it is possible to get excellent results from the treatment of pilonidal disease irrespective of the severity of the disease. The majority of patients with Type 1 and Type 2 pilonidal disease had acceptable outcomes with a low recurrence using non-excisional methods, but when excisional surgery was needed for patients with more extensive disease (such as a secondary sinus several centimetres away from the pits), good results were achieved. As seen in Fig. 2, excellent results can be achieved by treating patients appropriately by severity.

This supports the concept that treatment stratification in an algorithmic fashion is likely to result in excellent outcomes for all. The proposed algorithm in Fig. 5 allows patients to be streamlined into the appropriate treatment option for their particular presentation of the condition. These options would include Bascom’s pit picking, EPSiT, glue, laser and other non-excisional methods for Type 2 disease and off-midline closure such as cleft closure, Karydakis or simple flaps when excision is required.

Fig. 5.

Algorithm for the treatment of symptomatic pilonidal disease

It is of note that wide midline excision is not included in the algorithm, as we believe that this procedure, whether followed by laying open or closure of the wound, is never required in the treatment of pilonidal disease.

The PITSTOP study clearly demonstrated that patients preferred treatments that had a shorter recovery time and risk of persistence of disease [11]. Our results support the premise that, by applying this classification to the condition and treating it by severity, low recurrence rates can be achieved for all presentations. It is important that patients are not over-treated for pilonidal disease with the possibility that failure and recurrence will result in the patient being in a worse clinical condition than they were with their pilonidal disease before treatment. Using a stratification and algorithmic approach to the treatment of this condition can prevent this situation.

There are limitations to this study; this study illustrates the results of an experienced single surgeon with a specific interest in pilonidal and a vast breadth of experience. Nevertheless, we do not believe that this diminishes the underlying message of this study that, by stratifying patients according to disease presentation and tailoring offered treatments, patients may ultimately benefit. We also acknowledge that the follow-up period of our cohort may be considered short term; pilonidal disease is a benign condition affecting often the younger population, and in our experience we find it is often difficult to motivate patients to attend follow-up appointments, particularly if they are asymptomatic. Patients with good outcomes may be less motivated to return to further follow-up appointments, and vice-versa. Nevertheless, we encourage patients to get in touch should they have further symptoms even if they are treated elsewhere. We also offer an open-door policy whereby patients who develop any further symptoms after surgery can return for further assessment and intervention if required.

Conclusions

We believe that a “one procedure fits all” approach to pilonidal disease should be abandoned, and instead, surgeons offering treatment for pilonidal disease should have a range of treatments within their armamentarium to allow stratification by severity. This will allow better outcomes both in simple and more complex disease.

Author contribution

D.O. – design, data collection and processing, analysis and interpretation and writing manuscript. G.T. – data collection and processing, supervision, analysis and interpretation and critical review. A.S. – conceptualisation, design, supervision, data collection and processing, analysis and interpretation and writing manuscript.

Funding

All author(s) received no financial support for the research, authorship, and/or publication of this article.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Conflict of Interests

The authors declare no competing interests.

Ethics approval

Human ethics declaration not applicable.

Consent to participate

All patients had provided written consent to have their data analysed.