What Is Adult Scoliosis / Spinal Deformity?
Adult spinal deformity (ASD) is a three-dimensional deformity of the spine in people whose skeletal growth is complete. Its components include sideways curvature (scoliosis, a Cobb angle greater than 10 degrees), forward stooping (kyphosis) and flattening of the lumbar lordosis with forward leaning of the trunk (sagittal imbalance). The most common type is 'de novo' (primary degenerative) deformity: loss of disc height, facet arthrosis, asymmetric degeneration and osteoporotic fractures lead over time to a progressive curve; the typical patient is an older woman with osteoporosis. Other causes include progression in adulthood of childhood scoliosis and deformity following previous surgery.
Why Does 'Sagittal Balance' Matter?
In adult deformity the most important factor determining the functional outcome is 'sagittal balance' rather than appearance — that is, the ability of the trunk to stand upright in side profile. When this balance is disturbed, the patient compensates by bending the hips and knees to stay upright; this causes rapid fatigue and, in advanced cases, a forward-leaning, ground-facing posture. In surgical planning, spino-pelvic measurements such as pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and the distance of the C7 vertical line to the sacrum (SVA) are used; as the SVA increases, functional limitation, pain and fall risk increase. The treatment decision is therefore based not on the degree of the curve but on the patient's balance and complaints.
Symptoms
The most frequent complaint is low-back and upper-back pain that worsens with standing and walking and partly eases with rest. With sagittal imbalance the patient constantly exerts effort to stand upright and tires quickly. With accompanying canal stenosis, leg-radiating pain and leg complaints that worsen with walking (neurogenic claudication) appear, and radiculopathy with nerve-root compression. Appearance-related complaints (a hump, trunk asymmetry, height loss) and reduced quality of life often accompany. An important point: the degree of scoliosis alone does not require surgery; the decision is based on pain, balance and function.
When Conservative, When Surgery?
In mild-to-moderate symptomatic cases without marked imbalance, a conservative approach is taken: exercise and physiotherapy, core strengthening, pain management, osteoporosis treatment and, in selected cases, injections. Surgery is considered for progressive deformity, marked sagittal imbalance, resistant pain and neurological deficit. The goal is restoration of balance and lumbar lordosis together with adequate nerve decompression. Techniques include posterior fusion and instrumentation, interbody fusion and, when needed, osteotomies (PSO, VCR), with minimally invasive approaches in suitable cases. This surgery is a major undertaking; the decision requires careful patient selection and detailed planning.
Complications and Realistic Expectations
Adult deformity surgery is among the largest undertakings in spine surgery, and complication and revision rates can be higher than for other spinal operations: proximal junctional kyphosis (PJK), non-union of the fusion (pseudarthrosis), infection, blood loss and implant failure can occur; the risk rises especially in older and osteoporotic patients. To reduce these risks, osteoporosis optimization, measures to reduce blood loss and appropriate fusion strategies are applied. As for results, the honest picture: in appropriately selected patients, restoration of balance provides marked improvement in pain and function, but recovery is long and the risk is real. We do not promise a guaranteed outcome; all these possibilities are discussed openly before surgery.