Eur Surg (2011) 43/4: 236–243 Printed in Austria DOI 10.1007/s10353-011-0615-9 © Springer-Verlag 2011 Does gentamycin affect long term recurrence rate in pilonidal sinus surgery? D. Doll 1–3 , T. Evers 3 , E. Matevossian 2 , S. Hoffmann 1 , B. Krapohl 4 , D. Bartsch 1 1 Department of Visceral, Thoracic and Vascular Surgery, Philipps-University of Marburg, Marburg, Germany 2 Department of Surgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany 3 Department of Surgery, Military Hospital Berlin, Teaching Hospital of the Charité University Berlin, Berlin, Germany 4 Department of Plastic & Reconstructive Surgery, Military Hospital Berlin, Teaching Hospital of the Charité University Berlin, Berlin, Germany Received November 18, 2010; accepted after revision March 21, 2011; published online August 3, 2011 Summary. Background: The influence of topical intrao- perative gentamycin on long term recurrence rate in primary pilonidal sinus surgery has not yet been investigated. Methods: One hundred and eight-seven patients following excision of primary pilonidal sinus disease (PSD) and primary symmetrical midline closure were analysed regarding the use (group 1) or non-use (group 2) of topical application of an intraoperative gentamycin sponge after a median follow-up of 16 years by a specific questionnaire. Results: The actuarial 15-year-recurrence rate in group 1 was 31% (34/111) compared to 26% (20/76) in group 2, which was statistically not different (p ¼ 0.99). Recurrences occurred with a median 2.7 (range 0.1–20.1) years after primary surgery, so time to recurrence did not differ between both groups (4.3 ± 0.8 years group 1 vs. 6.8 ± 1.5 years group 2; p ¼ 0.99). Conclusions: The suggested positive effects of topi- cal gentamycin application on long term recurrence rate could not be confirmed. Astonishingly though, surgical infection does not seem to alter long term recurrence rate. Keywords: Pilonidal sinus, gentamycin, gentamicin, wound dehiscence, wound infection, long term recur- rence rate, epidemiology. Introduction Every pilonidal sinus, even though it may present ever clinically asymptomatic, is accompanied by acute, chron- ic or mixed acute-chronic soft tissue infection [1]. The soft tissue infection around the tracts is due to broken hair entering preexisting dimples or initially penetrating the skin, creating new sinus [2–10]. This mechanism takes place mostly during the vulnerable phase of sinus forma- tion [11] initiating a foreign body reaction. Tract forma- tion is further fuelled by the bacterial content present in the hair clefts and the inability of the immune system to digest and thus remove the intruding hair by phagocyto- sis. Infection may theoretically reside indefinitely even if the hair has left the lanceted tracts as soon as a surround- ing scar tract wall has been established. Hair leaving the tracts backwards has been shown to occur very unlikely due to its’ anatomical unidirectional barbs structure [9]. Thus, hair will generally move into the subcutaneous space more deeply and will form a pilo-nidus (lat. for hair nest), if more hair join in. Karydakis has suggested that hair may exit through the skin forming a new tract [4]. Early partial tract epithelialisation [12] is followed by scarring, reduced local perfusion and bacterial colonisa- tion. The mixed flora known to be present in pilonidal sinus consists of aerob and anaerob bacteria [13] which have been suspected to hamper wound healing, especial- ly in the presence of four or more species [14]. Chronic infection modulates tissue architecture in the way that more scarring and fibrin deposits will occur, with less tissue perfusion. In these areas systemic antibiosis may achieve only relative low local plasma levels as compared to virgin soft tissue. Topical antibiosis has been suggested to aid wound healing, which is known to be problematic in primary closed pilonidal sinus wounds. Wound break- down rates of 7% to more than 50% have been reported, with most of the dehiscence and abscesses arising within the first 2 weeks following surgery [15, 16]. Application of methylene blue into the sinus tracts at the time of surgery has been shown to remarkably reduce long term recurrence rate by 50% [17], while leaving wound dehiscence rates virtually unchanged. Correspondence: Dietrich Doll, M.D., Department of Visceral, Tho- racic and Vascular Surgery, Philipps-University of Marburg, Baldingerstraße, 35043 Marburg, Germany. Fax: þþ49-6421-58 62543 E-mail: ddoll@gmx.de 236 Eur Surg 4/2011 © Springer-Verlag Does gentamycin affect long term recurrence rate in pilonidal sinus surgery? Original Scientific Paper