Patients with posterior fusion defects such as spina bifida and meningomyelocele are known to have a high incidence of perianal and sacrococcygeal cutaneous problems, especially pilonidal sinus disease. Therefore, we aimed to investigate the prevalence of spina bifida and lower vertebral deformities in patients with pilonidal sinus disease.

In this study, we retrospectively reviewed conventional lumbosacral X-rays and lumbar CT scans of 25 patients treated surgically for pilonidal sinus disease at our hospital between 2005 and 2012. There were 19 male (76.0%) and six female (24.0%) patients. The mean age was 29.0 ± 6.9 (14–42) for the male patients and 27.0 ± 8.3 for the female patients. Lumbosacral X-rays and CT scans were re-evaluated by both radiologists and orthopedic surgeons, and patients diagnosed with occult spina bifida (OSB) were recorded.

A total of three patients (12.0%) with OSB were found. Two of these patients had a single-level posterior fusion defect at L5 or S1, while defects at both the L5 and S1 levels were detected in the third patient.

As a result, the OSB prevalence was found to be 12.0% when pilonidal sinus disease patients were retrospectively reviewed, which is considered to be a relatively high ratio. This finding may be due to both diseases having common genetic factors in their etiopathogenesis. In the light of these findings, we suggest that patients with pilonidal sinus disease should be screened with lumbosacral X-rays prior to surgery, to prevent possible further problems.

Keywords: Pilonidal sinus, spinal dysraphism, occult spina bifida, prevalence