Effects of pelvic tilt angles and forced vital capacity in healthy individuals

Effects of the posterior pelvic tilt sitting posture on thoracic morphology and respiratory function

[Purpose] We investigated how differences in pelvic angle in the posterior pelvic tilt sitting posture simultaneously affect the thoracic morphology and the respiratory function. [Participants and Methods] The participants were 18 healthy young males. We positioned the pelvis at 0°, 10°, 20°, and 30° of posterior tilt, following which the thoracic expansion volume ratio, thoracic spine tilt angle, and respiratory function were measured. We calculated the thoracic volume and thoracic spine tilt angle by measuring the amount of displacement of reflective markers attached to the thoracic area using the Vicon MX 3D-analysis system. Respiratory function was measured by spirometry. [Results] The expansion volume ratio decreased significantly in response to 10-30° posterior pelvic tilt sitting at the mid-thorax and 30° posterior pelvic tilt sitting at the lowest thorax. The upper thoracic spine level showed a change in anterior tilt at 10-30° posterior pelvic tilt sitting, whereas the lower thoracic spine level showed a change in posterior tilt at 30° posterior pelvic tilt sitting. Respiratory function was significantly lower at 30° posterior pelvic tilt sitting than at 0° posterior pelvic tilt sitting. A positive correlation between thoracic expansion volume ratio and respiratory function was found at 30° posterior pelvic tilt sitting. [Conclusion] Changes in thoracic spine tilt angle due to posterior pelvic tilt sitting may restrict the expansion of thoracic motion during respiration, thereby affecting respiratory function.

Posterior pelvic tilt is a risk factor for rectal prolapse: a propensity score matching analysis

BACKGROUND

There is little evidence about possible effects of pelvic anatomical characteristics on proctological complications. The aim of our study was to investigate the potential correlation between sagittal pelvic position and rectal prolapse.

METHODS

A study was conducted on a proctology patients and patients without any specific history of proctological disorders who were divided into two groups according to the presence or the absence of rectal prolapse. In all cases, the pelvic angle was measured with a pelvic goniometer and categorized as posterior (< 10°), neutral (10°-15°), and anterior (> 15°). To minimize effects of potential confounders in the analysis, 3:1 nearest neighbor propensity score matching (PSM) method was implemented using age, sex, and diagnose of rectal disorders as confounding variables.

RESULTS

Among the 143 screened patients, posterior tilt was more frequent in the 19 patients with rectal prolapse than in those without prolapse (42 vs. 18%; p = 0.027). This result was also confirmed in the post-PSM analysis (42 vs. 14%; p = 0.036) using 35 propensity score (PS)-matched controls compared with the rectal prolapse group. Posterior tilt was associated with an increased risk of prolapse in both the unmatched population (odds ratio = 3.37; p = 0.020) and PS-matched subset (odds ratio = 4.36; p = 0.028).

CONCLUSIONS

A posterior pelvic angle was more frequently associated with the diagnosis of rectal prolapse. In both the entire population and in the PS-matched subset, posterior tilt was a significant risk factor for rectal prolapse. The easy-to-do investigation of the pelvic angle can provide several benefits in terms of rectal prolapse prevention and more precise management of post-surgical prolapse recurrence.