Introduction

Management of pilonidal sinus disease (PSD) is important as any prolongation of treatment process results in delay in return to daily life [1]. Because of longer return to daily life and high recurrence rates seen after conventional PSD surgeries, the search for new treatment modalities continues. In fact, as a result of the disadvantages of excisional methods including longer recovery period and higher postoperative complications and recurrence rates, attention has been directed towards minimally invasive modalities [2, 3].

Accordingly, efforts are being made to develop better minimally invasive methods with the aim to improve postoperative comfort and minimize recurrences. In this regard, some procedures such as phenol, laser, fibrin glue use, platelet-enriched plasma application, pit picking, and sinusectomy have gained popularity in clinical practice [2, 3]. Yet, not all of these procedures are suitable for every patient and therefore selection of the best technique in each case is still regarded as of paramount importance. Factors like the extent of disease, the patient’s daily living conditions, and age are essential for the selection process [4].

In this study, we aimed to analyze short- and mid-term results of laser treatment for PSD and investigate the role of endoscopic camera use in the laser technique.

Methods

A total of 106 patients who were treated for PSD with laser between November 2017 and September 2021 were included in this study. Informed consent was obtained from all patients. The study protocol was approved by the Ethics Committee of Acibadem Mehmet Ali Aydinlar University (ID number 2022-20/01).

Data were collected from patients themselves and electronic medical records, and analyzed retrospectively. Additionally, in September 2022, 98 (92%) patients were contacted either by phone calls or through outpatient office visits and further data on clinical outcomes and recurrence were obtained. The remaining eight patients could not be reached, thus only the data on postoperative short-term outcomes were analyzed, and these patients were not included in the analyses of mid-term outcomes. The follow-up period was determined as a minimum of 1 year. The mean follow-up period was 30.9 ± 13.8 months in this study.

Since no certain indications for laser procedure exist in the PSD guidelines, we implemented the laser treatment according to the suggestions obtained from the current literature [5,6,7]. In addition, physical examination findings played an important role in patient selection in our clinical practice. Regardless of the number of sinuses, pits or recurrence(s), patients with a sinus diameter of less than 1 cm with preserved skin and tissue integrity were deemed suitable for laser treatment. In accordance with current literature, advantages as well as possible complications and recurrence risks of the laser method were explained to the patients. Laser treatment was not offered to patients who had an abscess, a sinus diameter of more than 1 cm, or disintegrated skin.

The primary aim of this study was to evaluate the short- and mid-term outcomes of laser treatment for PSD. The outcomes included operative time, postoperative pain, postoperative complications, hospital stay, return to daily life, complete recovery time, patient satisfaction, and recurrence. The secondary aims were to assess the role of endoscopic camera use in postoperative outcomes and analyze the effect of previous procedures for PSD on the outcomes of laser treatment.

Age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) score, history of smoking, alcohol use, previous abscess drainage, operative characteristics including operative time, endoscopic camera use, postoperative 24-h pain score, hospital stay, complications and readmissions within 30 days, return to daily life, time to complete recovery, recurrence, patient satisfaction, and total follow-up period were recorded. Pain severity during postoperative 24 h was evaluated with a numerical rating scale (NRS; 0, no pain; 10, very serious pain) [8]. Pain severity of 1–4 was considered as mild, 5–7 as medium, and 8–10 as severe pain. A modified Likert scale (1, not satisfied; 10, very satisfied) was used to evaluate patient satisfaction 1 year after the operation [9].

Time to complete healing was defined as complete closure of the wound(s) and epithelialization of skin. Recovery over 2 months was defined as late recovery. Seroma, bleeding, and purulent discharge were considered as complications. Non-epithelialization of the wound 3 months after operation, continuation of discharge, reoccurrence of discharge after epithelialization or formation of abscess, pit or sinus formation were defined as recurrence [10, 11]. Although follow-up period was determined as a minimum of 1 year, patients with a postoperative follow-up period of less than 1 year but who developed recurrence within the first year were included in the recurrence analyses.

As a secondary aim, the effect of camera use on the aforementioned outcome parameters was analyzed. Endoscopic camera was used in 73 (69%) of the patients to confirm the absence of hair and debris depending on surgeons’ preference. In addition, patients were analyzed in two groups for recurrence and complete recovery: one group with a history of previous PSD operation undergoing laser treatment and the other group undergoing laser treatment as primary procedure.

Surgical procedure

Preoperatively, one dose of 1 g cephazolin was administered for antibiotic prophylaxis. Under general anesthesia, patients were positioned prone, gluteal area was shaved, and asepsis was provided with povidione-iodine solution.

In the non-camera group, following cannulation of all sinuses and pits with a fistula probe (Fig. 1a), the most proximal and distal areas were excised with a suitable size (3, 4, 6, or 10 mm) punch biopsy scalpel, leaving a 1-mm skin border around pits or sinuses. Hair and/or debris in sinus tracts was cleaned with a surgical clamp and brush, and the tunnel was washed with isotonic solution. Then, the tract cavity was ablated with a 1470-nm diode laser probe, Ceralas® or Leonardo Dual 45® (Biolitec Biomedical Technology GmbH, Jena, Germany) with 13 W power for 6 s (Fig. 1b). The laser pulses were applied approximately for each 1-cm area with 78 J of energy. The laser probe was advanced back during the process and the walls of the tract were ablated equally. We modified the frequency of laser shots depending on the size of cavity. After the first ablation session, the necrotic tissue was cleaned again with a surgical clamp and brush. Finally, the same laser ablation was repeated for the second time and the cavity was totally sealed in the same session.

Fig. 1
figure 1

Cannulation of sinuses with a fistula probe (a) and ablation of the tract cavity with a laser probe (b)

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In the camera group, after the sinus tracts were cleaned, the cavity was filled with saline solution and the presence of hair or debris was checked with a videoendoscopic system harbouring a 4-mm endoscopic camera (Fig. 2a). Any hair or debris was cleaned. The cavity was checked once again with the videoendoscope to confirm the absence of hair or necrotic tissue (Fig. 2b). Then, laser treatment was performed in two series to ablate the cavity, as described for the non-camera group.

Fig. 2
figure 2

Following laser ablation, checking the cavity with a 4-mm endoscopic camera (a) and confirmation of the absence of hair or necrotic tissue (b)

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At the end of the procedure, an ice pack was applied for 5 min to cool off the operative area in all the patients. The external openings were not closed. Gauze dressing was applied to the operative area.

Because of the use of general anesthesia, patients were advised to stay one night at hospital. However, those patients who wished to be discharged on the same day as the operation were not prohibited from doing so. Patients were routinely prescribed nonsteroidal anti-inflammatory drugs and a proton pump inhibitor at discharge, and were allowed to take a shower any time after surgery.

Statistical analysis

Categorical variables were expressed as absolute and relative frequencies and chi-squared or Fisher’s exact tests were used for comparisons as appropriate. Continuous variables were expressed as mean ± SD and analyzed by unpaired Student’s t test or Mann–Whitney U test. Differences between the groups were statistically significant when p < 0.05. SPSS software (ver. 25.0 for Windows; IBM Corp., Armonk, NY, USA) was used for statistical analysis.

Results

Of the 106 patients, there were 80 (75%) men and 26 women with a median age of 26 (range 13–50) years. The mean BMI was 26.1 ± 4.3 kg/m2. The mean number of pits or sinuses was 2.5 ± 1.9. There was a history of abscess in 31 (29%) patients. Thirty-two (30%) patients had undergone previous surgery for PSD. Demographics and preoperative clinical data are provided in Table 1.

Table 1 Patient demographics and clinical characteristics
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Overall, the mean operative time was 15.2 ± 4.9 min. The mean length of hospital stay was 0.9 ± 0.4 days, 16 patients were discharged on the same day of operation while 90 patients (84.9%) stayed one night. The mean interval time to return to daily life was 4.5 ± 5.5 (median 2, range 1–30) days, respectively. The mean NRS value was 2.6 ± 2.5 out of 10. On the first postoperative day, 26 (26.5%) patients did not describe any pain while 42 (42.8%) patients reported low-grade pain and only four (4%) had severe pain (Fig. 3). Postoperative complications occurred in 11 (10.4%) patients: purulent discharge in seven patients, seroma formation in three, and bleeding in one patient. Since there were no other signs of infection in the skin and subcutaneous tissue in these patients, the presence of purulent discharge only was not considered as wound infection. The mean recovery time was 27.4 ± 15.9 (median 25, range 7–75) days. Two (1.9%) patients were readmitted because of pain. Complete recovery was delayed in three patients. As eight patients who were excluded from the analysis due to dropping out during the follow-up period, 86 (87.8%) patients had complete healing. The mean satisfaction score was 9.5 ± 1.0 out of 10. Sixty-seven patients (63.2%) were very satisfied, 31 (29.2%) patients were satisfied, and one patient (0.9%) was moderately satisfied. Taking into account the excluded patients, overall patient satisfaction reached 99.0% (Table 2) (Fig. 4).

Fig. 3
figure 3

Postoperative 24-h pain scores (NRS numerical rating scale)

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Table 2 Early and late clinical outcomes of PSD laser ablation treatment
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Fig. 4
figure 4

Likert scale for patient satisfaction

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During the follow-up period of 30.9 months, recurrence occurred in 12 (11.0%) patients. Among these, six patients had recurrence in the first year (1, 1, 2, 3, 4, and 7 months), three in second year (13, 15, and 18 months), and the remaining three in the third year (28, 31, and 35 months). In those considered as recurrences, there was no improvement in two patients (primary failure) whereas ten patients showed recovery initially but pits were reopened later in the follow-up period (secondary failure). Recurrence developed in two of 31 (6.5%) patients with a history of previous abscess. Among the patients with complicateds, two (12.5%) patients had recurrence. History of previous surgery, abscess formation at least 6 weeks before laser procedure, or postoperative complications were found to have no impact on recurrence (Table 3). Additionally, recurrence was not observed in patients who had late recovery (p > 0.05) (Table 3).

Table 3 Comparison of recurrence rates with respect to previous PSD operation, abscess, or postoperative complications
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Perioperative characteristics are compared between camera versus non-camera groups in Tables 4 and 5. There were statistically no significant differences between the two groups in terms of demographics and preoperative clinical characteristics except BMI was higher in the camera group (26.8 ± 4.07 vs 24.6 ± 4.45 kg/m2, p = 0.02). The operative time increased at least 1.5-fold in the camera group and this was statistically significant (17.3 ± 4.3 vs 10.7 ± 2.9 min, p = 0.001). The mean length of hospital stay was higher in the camera group (0.9 ± 0.3 vs 0.7 ± 0.5 days, p = 0.02). The rate of same-day discharge was higher in the non-camera group (30.3% vs 8.2%, p = 0.007). There were no significant differences between two groups with respect to postoperative pain, complications, readmissions, recurrences, complete recovery time, and patient satisfaction.

Table 4 Comparison of clinical characteristics between the camera and no-camera groups
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Table 5 Comparison of perioperative characteristics between the camera and no-camera groups
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In our cohort, 74 patients had laser treatment as primary procedure and 32 patients had a history of previous procedure for PSD. The complete recovery and recurrence rates did not differ between these two subgroups (90.0% vs 82.1% and 10% vs 18%, p > 0.05) (Table 3). The patient flowchart is given in Fig. 5.

Fig. 5
figure 5

Flowchart of patients with or without a previous procedure for pilonidal sinus disease undergoing laser treatment

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Discussion

In this study, we evaluated the short- and mid-term outcomes of laser ablation treatment as a minimally invasive technique in 106 patients with PSD. Our preliminary results with this technique show short operative time, low postoperative pain, rapid return to daily life, high patient satisfaction scores, and relatively low recurrence rate. These results confirm the accumulating data that laser treatment can be considered a safe and efficient procedure in PSD management. Considering the relevant studies reported in the literature, a unique aspect of this study is that we employed an endoscopic camera to confirm the absence of disease before terminating the procedure in the majority of patients (69%). However, we found no additional benefit of using the endoscopic camera in terms of postoperative outcomes in our patient cohort.

Use of minimally invasive techniques in PSD dates back to the 1960s [12]. Especially in the late 1980s following the introduction of Bascom’s technique [13], these techniques have gained a wide interest in surgeons’ clinical practice. Considering conventional excisional methods, although early complete recovery is crucial, there is still no 100% chance of success. It has been shown that there is a recurrence rate of 0.4% and 1.6% in the Limberg flap and 0.2% and 0.6% in the Karydakis procedure in 1- and 2-year follow-up periods [14]. In fact, 5-year recurrence rate of invasive techniques varies between 10% and 30% and complication rates are still relatively high. In a study on microsinusectomy as a minimally invasive technique including 1358 patients, Gips et al. [15] report the recurrence rate of 16.2% in a 7-year follow-up period. Laser surgery which was originally used in benign anorectal diseases in the early 2000s is now being studied frequently as an alternative method in PSD treatment [16, 17]. The main purpose of these developments in the minimally invasive techniques is to provide faster recovery with less pain and to decrease complication and recurrence rates. Considering all these, recent data supports the use of laser technique in suitable patients [10, 14, 18]. In a study by Algazar et al. [19] in which Limberg flap and laser surgery are compared, it is shown that laser treatment is comparable to flap methods in terms of recovery time and recurrence rates. We believe that Limberg flap, although it is still a commonly used technique in clinical practice, would be overtreatment for many and offering this major surgery would not be appropriate to all patients who could well be served by laser or other non-excisional methods. In another study, recurrence rates after laser treatment are reported to be 1.9% and 5.1% after 1 and 2 years, respectively [14]. This ratio reaches 36% in 5-year follow-ups [11, 14]. Nevertheless, available data on laser use are still inadequate and there are still no large cohort studies in the literature. Because of lasting concerns and intention to improve the recovery from PSD, we have been providing laser treatment as an alternative option to our patients in recent years.

We emphasize that nearly 90% of patients benefited from laser treatment with early return to daily life and favorable outcomes. We observed the advantages of this technique such as safer surgery, minimal morbidity, aesthetic satisfaction, and earlier return to daily life without restriction of movement. Studies show that over 95% recovery occurs within 2–3 weeks and full recovery is achieved after 1 month [11, 17, 20]. Although the average recovery period was 1 month, patient satisfaction reached 99% because healing continues along with patients’ daily life and this rate was concurrent with literature (98%) [1, 17, 20]. The duration of complete recovery was 27.4 days. Recurrence occurred at an acceptable rate of 11%. Unexpectedly, eight patients with recurrence reported full satisfaction. The possible reason for high satisfaction even in these patients would be the detailed information given preoperatively and comfortable postoperative period with early return to daily life. Several studies have shown that there is a risk of recurrence especially in first 5 years; however, this tendency decreases afterwards [2, 14, 21].

As an alternative minimally invasive approach, endoscopic pilonidal sinus treatment (E.P.Si.T.), which was first described by Meinero et al. in 2012, has taken its place among other treatment options as an effective, safe, and less invasive method [22, 23]. Laser treatment can also be performed with an endoscopic camera to visualize sinus tracts more clearly, to clean the cavity more effectively, destroy the granulation tissue, and evaluate hemostasis adequacy [24, 25]. In a study by Gulcu and Ozturk [26], laser with E.P.Si.T. and E.P.Si.T. alone were compared and it was shown that laser treatment was superior to Meinero’s standardized E.P.Si.T. in terms of postoperative comfort, faster wound healing, and rapid return to work [22]. A distinctive difference from these previous studies is that we evaluated the role of the camera in the efficiency of laser treatment with the presumable additional advantage of this combined treatment modality. Interestingly, we found that camera use did not make any difference on postoperative outcomes such as pain severity, complete recovery, complications, readmissions, recurrences, and patient satisfaction. Besides, it was associated with longer operative time and hospital stay. Of note, the longer hospital stay in the camera group with a mean statistical difference of 0.2 days should not be considered clinically significant since all patients were discharged within the first postoperative day. Future prospective studies with a higher number of patients may better evaluate the role of endoscopic camera use in this procedure.

PSD may present with an acute abscess. In this case, curative surgery is generally recommended 2–6 weeks after abscess drainage [1, 4, 26]. Therefore, similar to most studies, laser treatment was not performed in patients with an acute abscess in our study. Twenty-nine percent of patients with an abscess underwent laser treatment after awaiting the appropriate time. These cases can also be considered as complex cases since patients generally present later in the course of disease and therefore have a larger cavity, a larger granulation tissue, and hair content inside sinuses. However, only two such patients developed recurrence, and postoperative antibiotic therapy was preferred in these cases. Although there are contradictory data in the literature, current guidelines recommend antibiotherapy on a patient-specific basis with moderate-quality evidence [3, 27].

Considering patients undergoing laser therapy, number of pits or sinuses treated with laser is usually limited in order to increase the chance of success [4]. Excision and flap methods are preferred in patients with more pits or sinuses [4, 28]. In our study, laser was applied regardless of the number of pits or sinuses with suitable skin integrity. The mean number of sinuses was 2.5 ± 1.9. In fact, laser treatment was also applied to a patient with 10 pits and sinuses, and no recurrence occurred in this case after a follow-up period of 33 months. Albeit rare, this case demonstrates that regardless of the number of pits or sinuses, complete recovery can still be possible with the correct indication and intervention with laser. The complication rate of laser surgery is reported to range from 3.3% to 25% and includes abscess, hematoma, seroma, wound infection, ischemia, and wound discharge [2]. In this study, complications developed in 10.4% of patients. Wound infection did not develop in any patient. Furthermore, complications seem to have no impact on the development of recurrence. It was also observed that camera use did not affect the complication rate. Despite all possible complications, it is important to keep in mind that surgical excision methods can still be performed in patients who develop recurrence even after laser treatment since this treatment modality does not involve excision.

Although laser is more costly than more invasive excisional and flap methods, it can still be regarded as cost-effective overall since patients can be discharged within first postoperative day and return to daily life is faster. Minimal postoperative pain is one of the important advantages of laser therapy [2, 19, 29]. In our study, rate of postoperative pain was very low, supporting current literature. Altogether, these unique advantages of laser treatment may contribute to its cost-effectiveness.

The retrospective nature and relatively small number of patients are important limitations of this study. Also, having no guideline or consensus on laser treatment for PSD precludes a standardized approach. Taking these limitations into account, favorable results may have been masked especially when laser procedure was implemented with an endoscopic camera. Considering that there is no data regarding the role of endoscopic camera use in laser procedure, this combined treatment modality still increases the value of this study and may provide insight to further evaluate its role.

Conclusion

Laser therapy for PSD is a minimally invasive and safe procedure with advantages of less pain, low complication rate, short hospitalization and rapid recovery, high patient satisfaction, and acceptable recurrence rates. The use of a camera in laser treatment does not seem to add a significant benefit. Therefore, further studies with a large number of patients are required to investigate laser treatment and special attention should be directed to the role of endoscopic camera use.