Coccigodínias: diagnóstico por imagem / Coccygodynia: diagnostic imaging

Coccigodínia é uma síndrome dolorosa de difícil abordagem diagnóstica e terapêutica, ainda mal compreendida por clínicos, ortopedistas e radiologistas. No intuito de entender e diferenciar as anormalidades clínico-radiológicas encontradas nas coccigodínias, revisamos a anatomia normal do sacro-cóccix e das demais estruturas pélvicas, suas variações e alterações anatômicas, além doselementos biomecânicos e fisiopatológicos implicados na etiologia da dor. O estudo radiológico funcional do cóccix consiste na obtenção de incidências de perfil nas posições ortostática e sentada, que permite a determinação da mobilidade coccígea. Este método pode demonstrar lesãocausal em 70% dos casos de coccigodínia. A classificação radiológica segundo as alterações da dinâmica do cóccix pode orientar tratamentos e comparar respostas terapêuticas por subgrupos.

Coccygodynia is a painful syndrome still misunderstood by physicians. To understand the radiological abnormalities that may accompanythis syndrome we have revised sacro-coccygeal normal anatomy and its variants and biomechanical elements that may produce pain. Functional radiologic studies of the coccyx consistin lateral projection in upright and sitted positions. Such projections provide clues for the evaluation of coccygeal mobility and may disclose the causal lesion producing coccygodynia in about 70%of the patients. Radiologic classification of the dynamic dysfunctions of coccygeal mobility may orient treatments and compare outcomes in subgroups.

Clinical and radiological differences between traumatic and idiopathic coccygodynia

Several reports of coccygodynia have been confined to the causes, the methods of treatment, and the methods of radiological examination. As far as we know, there has been no previous study about the objective measurement of the coccyx. The purpose of this study was to find the possible cause of idiopathic coccygodynia by comparing the clinical and radiological differences between traumatic and idiopathic coccygodynia by innovative objective clinical and radiological measurements. Thirty-two patients with coccygodynia were evaluated retrospectively. We divided the patients into two groups. Group 1 consisted of 19 patients with traumatic coccygodynia and group 2 consisted of 13 patients with idiopathic coccygodynia. We reviewed medical records and checked age, sex distribution, symptoms, and treatment outcome in each group. We also reviewed coccyx AP and lateral views of plain radiological film and measured the number of coccyx segments and the intercoccygeal angle in each group. The intercoccygeal angle devised by the authors was defined as the angle between the first and last segment of the coccyx. We also checked the intercoccygeal angle in a normal control group, which consisted of 18 women and 2 men, to observe the reference value of the intercoccygeal angle. The outcome of treatment was assessed by a visual analogue scale based on the pain score. Statistical analysis was done with Mann-Whitney U test and Chi-square test. Group 1 consisted of 1 male and 18 female patients, while group 2 consisted of 2 male and 11 female patients. There were no statistically significant differences between the traumatic and idiopathic coccygodynia groups in terms of age (38.7 years versus 36.5 years), male/female sex ratio (1/18 versus 2/11), and the number of coccyx segments (2.9 versus 2.7). There were significant differences between the traumatic and idiopathic coccygodynia groups in terms of the pain score (pain on sitting: 82 versus 47, pain on defecation: 39 versus 87), the intercoccygeal angle (47.9 degree versus 72.2 degrees), and the satisfactory outcome of conservative treatment (47.4% versus 92.3%). The reference value of the intercoccygeal angle in the normal control group was 52.3 degrees, which was significantly different from that of the idiopathic group. In conclusion, the intercoccygeal angle of the idiopathic coccygodynia group was greater than that of the traumatic group and normal control group. Based on the results of this study, the increased intercoccygeal angle can be considered a possible cause of idiopathic coccygodynia. The intercoccygeal angle was a useful radiological measurement to evaluate the forward angulation deformity of the coccyx.