Pilonidal sinus is an infection of the skin and subcutaneous tissue near the upper part of the natal cleft. It is caused by hair penetrating and becoming trapped in the skin. Surgical excision is often required for chronic cases. Primary closure has faster healing but higher recurrence, while delayed closure has slower healing but lower recurrence. Off-midline primary closure has better outcomes than midline with respect to time to heal, infections, and recurrence rates. Lateral advancement flaps like Karydakis have shown slightly better results than Limberg flaps for off-midline closure. Antibiotics generally only have a role if cellulitis is present.

1. Pilonidal sinus
Dr. Zeeshan

2.  Definition: Infection of the skin and subcutaneous tissue
at or near the upper part of the natal cleft of the
buttocks.
NOT a true cyst

3. History
 1833- hair containing cyst located just below the coccyx
Mayo
 1880- Hodge coined the term “pilonidal”
Nest of hair
 In 19th
and 20th
century – considered to be congenital

4.  In WW II
 Patey and Scarf – hypothesised origin of pilonidal sinus
acquired by penetration of hair into subcutaneous tissue.

5. What causes pilonidal sinus???
 Midline holes – Hair follicles that have enlarged
Pulling forces between sacrum and skin
 Force concentrate on 1mm2 area where the narrow
gluteal crease comes in close contact with the sharp
angle of sacrum

6.  Weakest point of skin gives way first– Skin at the bottom
of the follicle.
 Primary cause – “Pit”
 Secondary casue – “ Hair follicles”

7. Cause of pilonidal sinus
 (1) Invader hair
 (2) Force causing hair penetration
 (3) Vulnerability of skin

8. Anatomy
 Intergluteal cleft: A groove between the buttocks that
extends from just below the sacrum to the perineum.
Anchoring of the deep layers of skin overlying the coccyx
to the anococcygeal raphe

9. Epidemiology
 Incidence : 26 per 100,000
 Mean age: 19 years for women and 21 years for men
 Sex: M/F ratio – 2:1 to 4:1
 Equal incidence of acute:chronic

10. Risk factors
 Overweight/ obesity
 Local trauma or irritation
 Sedentary lifestyle/prolonged sitting
 Deep natal cleft
 Family history

11. Theory
 Acquired vs Congenital
 Tendency to recur following complete excision.
 Tendency to occur in places other than natal cleft.

12. Pathogenesis
 Hair and inflammation – inciting factors
 On sitting/bending natal cleft stretches- breakage of
follicles- opening of a pore/pit- collection of debris
- pilonidal sinus - abscess
 Proof??
 Pilonidal tract extends cephalad.
 Cavity contains hair, debris or granulation tissue.

13. Clinical manifestations
 Patient presentation:
- Acute onset mild to severe pain (sitting/bending)
- Intermittent mucoid/purulent/bloody discharge
- Recurrent / persisting pain
- Fever / malaise

14. Physical examination
 One/more pits in the natal cleft +/- painless sinus opening
cephalad and lateral to cleft
 Tender mass or sinus draining mucoid/bloody or purulent
fluid

15. Diagnosis
 Clinical
- Finding a pore/sinus in the natal cleft
- No imaging required

16. Differential diagnosis
 Perianal abscess/ fistula
 Hidradenitis suppurativa
 Perianal complications of Crohn’s disease
 Skin abscess/ furuncle/ carbuncle
 Folliculitis

17. Surgical treatment
 Drainage with/ without excision
 Marsupialisation
 Excision with primary closure
 Excision with grafting
 Sinus extraction
 Sclerosing injections

18. ACUTE ABSCESS
-- Incision is performed lateral to
midline midline over area of maximum
fluctuance
- Packing of the wound
- Marsupialisation

20. Problems
 Recurrence rates are from 20 – 55 %
 During a 3 year period, 73 patients treated with I & D for
first episode of pilonidal abscess
 Healed : 42 patients (58%; 95% CI) within 10 weeks
 Recurrence : 9 patients (21%;95% CI)
 Follow up period : median of 60 months
 Constant cure rate : 76% (CI 95%) after 18 months
Prognosis after simple incision and drainage for a first-episode acute pilonidal abscess.
 Jensen SL, Harling H
 Br J Surg. 1988;75(1):60.

21. Chronic pilonidal sinus
Surgical approaches:
- Excision
- Wound closure
(1)Primary closure in midline/ off midline
> Z plasty
> V-Y advancement flap
> Rhomboid flap (limberg)
(2) Reconstruction using flaps

22. Karydakis surgery
 Karydakis believed that hair insertion is the cause for
pilonidal sinus
 Low recurrence rates due to:
- Wound placed away from midline
- Resulting new natal cleft was shallower
 Problems
- Sutured taken over the presacral fascia causing pain
- Patients requiring GA
- Prolonged hospital stay

24. Modified Karydakis/Basscom II/Cleft
lip
 Use of shallow cleft
 Under LA
 Causes less pain as presacral fascia not included

25. Z- plasty

26. Z-plasty for pilonidal sinus

27. 
 V-Y Plasty

28. Limberg flap

30. Primary versus delayed closure
 Time to wound healing:
- Total of 13 trials done (n= 1421) included data for time
for wound healing (not aggregrated due to high
heterogeneity)
- 9 trials reported a faster time to wound healing following
primary closure.
- Largest trial (n=380) found that patients undergoing
primary repair had a significant faster wound healing rate
compared to open wounds(14.5 versus 60 days)
- Excision with or without primary closure for pilonidal sinus disease.
- Al-Salamah SM, Hussain MI, Mirza SM; J Pak Med Assoc. 2007 Aug;57(8):388-91.

31.  Time to return to work:
- A total of 11 trials done (n=1729)
- 9 studies reported a faster return to work following
primary closure
- The largest study (n=144) found that patients had a faster
return to work following primary repair compared to
delayed closure.(11.9 versus 17.5 days)
Comparison of outcomes in Z-plasty and delayed healing by secondary intention of
the wound after excision of the sacral pilonidal sinus: results of a randomized,
clinical trial.
Fazeli MS, Adel MG, Lebaschi AH
Dis Colon Rectum. 2006 Dec;49(12):1831-6.

32.  Recurrence rates:
- Based on 16 trials including 1666 patients , the overall
recurrence rate was 6.9%.
- Primary wound closure was associated with a HIGHER
recurrence rate compared to delayed wound closure.
(8.7 versus 5.3 percent, relative risk RR [1.5] CI1.08-2.17

33.  Rate of surgical site infection:
- Based on 10 trials including 1231 patients
NO SIGNIFICANT DIFFERENCE between primary and
delayed wound closure and risk of SSI
(8 versus 10% , RR 0.76, CI 0.54-1.08)

34. Off midline versus midline primary
sutured closures
 Sutured off midline wounds – less time to heal (n=100 ,
mean difference 5.4 days, 95% CI 2.3-8.5)
 Risk of SSI was significantly lower for off midline wounds
(n=541, RR 0.27, CI 0.13-0.54)
 Risk of recurrence LOWER for off midline wounds
(n=574, RR=0.22, CI 0.11-0.43)
 The overall complication rate was LOWER for off
midline wounds (n=461, RR=0.23, CI0.08-0.66)

35. Types of off-midline closure
 While an off midline approach is superior , optimal off
midline approach has not been identified.
 Two trials were perfomed to determine recurrence and
complications rates between lateral advancement flaps
( modified Karydakis) and modified Limberg’s flap

36. N = 120 Karydakis lateral
advancment flap
Limberg’s
flap
Wound disruption 0 patients 9 patients
Rate of
complications
23 % 40 %
Wound infection 3% 5%
Subcutaneous fluid
collection
5% 0%
Hypoaesthesia 10% 23%
Recurrence rates 3% 2%
Comparison of short-term results between the modified Karydakis flap and the modified Limberg flap in the
management of pilonidal sinus disease: a randomized controlled study.
Bessa SS
Dis Colon Rectum. 2013;56(4):491.

37. N=295 Karydakis flap Limberg
Seroma formation 19.8% 7.4%
Wound dehiscence 15.4% 3.7%
Flap maceration 11% 3.7%
Which flap method should be preferred for the treatment of pilonidal sinus? A prospective randomized study.
Arslan K, Said Kokcam S, Koksal H, Turan E, Atay A, Dogru O
Tech Coloproctol. 2013 Feb;

38. In summary
 Patients with acute pilonidal sinus – I & D
 For patients with chronic pilonidal sinus – An excision of
the sinus and all tracts
 A primary closure is associated with faster wound healing
– however a delayed closure is associated with less
recurrence
 For patients undergoing primary wound closure – off
midline closure recommended

39. Role of Abx
 Generally limited to clinical setting of cellulitis
 Indications:
- Immunosuppresion
- High risk for Endocarditis
- MRSA
- Concurrent systemic illness