The diagnosis of a tailbone fistula is an eye diagnosis. This means that the visible and palpable changes of the pilonidal disease are so typical that experienced examiners can usually make the diagnosis without major technical effort.
The pits or fistula openings in the gluteal fold are relatively easy to find and can be recognised by small, funnel-shaped retractions of the skin, possibly with sprouting hairs. If a chronic pilonidal cyst is present, depending on its size, it is already visible by a slight protrusion in the immediate vicinity of the gluteal fold; smaller ones are usually palpable as a circumscribed hardening under the skin. Depending on the inflammatory state of the cystic sinus, bloody-purulent secretion empties from the pits when pressure is applied to it.
Simple X-ray examination does not play a role in imaging procedures. Computed tomography and magnetic resonance imaging are generally dispensable, but can occasionally be helpful for surgical planning in complex plastic surgery.
A fast and uncomplicated, radiation-free imaging for the representation of the pilonidal cyst is possible with an ultrasound examination. The localisation and extent of a pilonidal cyst can be easily visualised with it, usually also the connection to the pits under the skin in the subcutaneous fatty tissue.
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| Pilonidal cyst in ultrasound image (c) MVZ St. Marien Cologne, Germany |
Literature sources:
Taylor SA, Halligan S, Bartram CI. Pilonidal sinus disease: MR imaging distinction from fistula in ano. Radiology. 2003;226 (3): 662-7
Mentes O, Oysul A, Harlak A et-al. Ultrasonography accurately evaluates the dimension and shape of the pilonidal sinus. Clinics (Sao Paulo). 2010;64 (3): 189-92
Imanishi H, Tsuruta D, Nomura N et-al. Clinical usefulness of ultrasonography in interdigital pilonidal sinus. J Cutan Med Surg. 2012;16 (3): 194-6
Adams CI, Petrie PW, Hooper G. Interdigital pilonidal sinus in the hand. J Hand Surg Br. 2001;26 (1): 53-5
