Pelvic obliquity (PO) is an orthopaedic condition, it is the misalignment of the pelvis, typically one hip is higher than the other. Or in more medical terms it is defined by a spinopelvic asymmetry in the frontal plane, the Anterior Superior Iliac Spine (ASIS) are not horizontally levelled. In a survey under a Dutch group of wheelchair users the self-reported prevalence of PO is 58%, the PO ranges from 2-4cm (4.5-9.1°).
There are three different causes of PO:
- Suprapelvic obliquity as a consequence of spinal pathology, such as scoliosis;
- Intrapelvic obliquity as a consequence of architectural bony defects inherent in the hemipelvis;
- Infrapelvic obliquity as a consequence of abduction or adduction hip contractures or limb length
PO can be categorized as functional/flexible, this means that the PO can be corrected, or as structural/fixed. A structural PO cannot be corrected, only accommodated. But in real life it is often a combination of both, partly functional & partly structural. Scoliosis, which is a sideways curve of the spine, can be either a cause or a consequence of PO. Other consequences of pelvic obliquity are pain, lack of postural stability and pressure injuries. Therefore it’s important to recognise PO and correct or accommodate PO with a suitable wheelchair cushion or other wheelchair set-ups.
Bolin et al. identified the wheelchair cushion as a factor in the development of PO, and advised the use of foam cushions for stability, but they did not investigate Vicair cushions.1 Inhouse research of Vicair found that the Vicair Adjuster O2 is highly suitable for accommodating a wide range of pelvic obliquity (4.5-9.1°) without the need to adjust the filling grade and without creating high pressure area’s.
There needs to be a balance between stability and pressure redistribution. By applying a compartmented air cell cushion, both stability and pressure redistribution can be optimized so pelvic obliquity can be prevented, corrected or accommodated.