Final answer:
A major risk factor for complications after posterior spinal fusion is the presence of developmental anomalies and pathological changes, along with obesity. These conditions may increase spinal curvature, which in turn heightens the shearing forces on the vertebrae, leading to possible hardware failure, pseudarthrosis, or nerve damage. It is critical to consider these risk factors during preoperative planning and patient counseling.
Step-by-step explanation:
A major risk factor for the development of complications after posterior spinal fusion, a surgery commonly performed for the correction of spinal alignments such as kyphosis, lordosis, and scoliosis, is the presence of developmental anomalies of the spinal column. These anomalies, along with pathological changes and obesity, can lead to excessive or abnormal curvatures that compromise the integrity of the spinal structure and function.
During the process of spinal fusion, increased curvature can intensify shearing forces on the vertebrae, particularly on the lower segments of the spine. This, in turn, can exacerbate the risk associated with the surgery and lead to various complications such as hardware failure, pseudarthrosis (failure of the bone segments to fuse properly), or nerve damage resulting from the spinal realignment. Moreover, conditions like osteoporosis that weaken vertebral structures can result in a more fragile surgical site and a heightened possibility of postoperative deformity or instability.
Overall, the spine's ability to withstand shear over compressional forces is crucial. Those with an increased spinal curvature and higher shearing forces may face a greater risk of back injury and complications post-surgery, including ruptured discs and persistent pain. This risk is particularly significant in the lumbosacral disc due to its positioning and role in bearing the weight and motions of the body.