American Journal of Physical Medicine and Rehabilitation
2010 April; 89 (4): S33.
Patrick M. Foye, M.D., Todd P. Stitik, M.D.,
Tailbone Pain Center, UMDNJ-New Jersey Medical School, Physical Medicine and Rehabilitation, 90 Bergen Street, DOC-3100, Newark, NJ, United States, 07103. Phone: (973)972-2802. Fax: (973)972-2825. tailbonedoctor.com/.
Case presentation: A 34 year-old female fell onto her coccyx while going down stairs, causing new-onset tailbone pain. She had no significant past medical history. When she presented to an outpatient musculoskeletal/pain practice one week later, musculoskeletal and neurologic physical exam was essentially normal except for focal, exquisite tenderness to palpation at the region of the sacrococcygeal junction.
Diagnostic ultrasound: In-office diagnostic ultrasound revealed a notable posterior coccygeal listhesis, compared with the more superior segment.
Diagnostic x-rays: Radiographs confirmed a 50% retrolisthesis of the first coccygeal segment (C1) relative to the lowest sacral segment (S5). The x-rays also revealed an avulsion fracture at the anterior aspect of the proximal C1 segment. Thus, the diagnostic ultrasound had detected the sacrococcygeal listhesis, but the ultrasound had failed to detect the fracture (perhaps due to its location being anterior and thus less superficial).
Conclusions: Regarding the diagnostic work-up for patients with coccyx injury and/or tailbone pain, this case it indicates that in-office diagnostic ultrasound may have some usefulness, but also may have some limitations.