The spine naturally has two moderate front-to-back curves. The cervical Lordosis, the thoracic spine(middle), has an outward curve medically termed as Kyphosis and the lower back (lumbar spine) with an inward curve medically called Lordosis. These spinal curves usually work in harmony to maintain your body’s centre of gravity aligned over your hip and pelvis. The main objective is to maintain equilibrium in the sagittal plane, and the coronal plane joined from the middle of cranial mass, femoral heads, and other lower extremities. This is called the sagittal balance.
The constant sagittal balance of the spine is a physical alignment of the spine in the most efficient manner by muscular forces. During walking, this balance is disturbed continuously with single-foot support. As a result of this sagittal balance, when looking at a normal person from above, we can notice that the head’s projection will be the same as that of the pelvis.
However, if any of the curves become too curvy or too flat, your spine will lose balance back-to-front. This is a sagittal imbalance, and it is of two major types, Flatback Syndrome, and Kyphosis. Overall spinal balance relies on the connection between the pelvic factors and the Lumbar Lordosis.
You can observe sagittal imbalance through symptoms such as lower back pain, difficulty to walk, and inability to look constantly straight ahead when upright.
What Disturbs Sagittal Balance Of Spine?
Spinal deformity in the sagittal plane is nowadays one of the significant reasons for back pain and disability among many patients. Normal sagittal balance is associated with the mutual connection of the pelvis and the spine in the sagittal plane. Sagittal spinal imbalance of the spine is associated with many spinal pathologies affecting your spine .These also can happen when a surgery is not
Sagittal malalignment is not restricted to adult spinal deformity; it extends through other spinal disorders. Some causes that alter the sagittal balance are mentioned below:
- Ankylosing spondylitis, a rare type of arthritis
- Excessive forward curvature of the spine called Kyphosis
- Degenerative spinal conditions like disc disease, wear and tear of the discs cushions in the spine
- Trauma or injuries to the spine
- Birth defects or congenital disabilities
- Osteoporosis – multiple osteoporotic fractures lead to dowagers hump and kyphosis
- Old healed tuberculosis or neglected spinal deformities also results in a sagittal imbalance
A previously performed spinal fusion not restoring the balance might also disrupt the sagittal balance. For instance, sagittal imbalance may develop in patients who have undergone rods’ implantations to correct the spinal curvature of scoliosis.
Distraction instrumentation of lumbar spine without restoring lordosis and these are known as a flat back syndrome.
Sagittal Balance and Spine Surgery
The causes of sagittal imbalance are different from patient to patient. Similarly, the way of sagittal balance management also varies. However, the overall goal of the operations is the same, i.e., to restore the sagittal balance of the spine. Generally, the problem is due to spinal deformities, i.e., either there is not enough Lordosis or too much Kyphosis, surgery is usually intended to add Lordosis or decrease Kyphosis, or both.
Correcting spinal disorders can restore the sagittal balance. Below are the treatment options to fix spinal problems.
Correcting the spinal deformity: The initial treatment options include soft tissue releases, facetectomies and other procedures. Osteotomy is only the last resort and in case of rigid deformities osteotomy is the only treatment option. During this process, a piece of bone from the spine is removed to create space for movement. The extent and area of bone removed depends upon various factors, like location and the type of spinal deformity.
Spinal fixation: After the correction of a spinal deformity, the spine needs to be stabilized with rods and screws and plates attaching to the spine.
Spinal fusion: The surgeon will implant bone graft material(pieces of bone) to fill the gaps between discs. The bones fuse together and grow further. It helps to make the spine stable and also restores sagittal balance. The long-term success of sagittal balance is achieved with good bone fusion surgery.
Note: Certain lifestyle factors, which include smoking and obesity, can manipulate bone fusion.
Several compensatory mechanisms are used in an attempt to maintain balance in a sagittally misaligned patient. However, if you are suffering from any spinal disorder, consult Dr Surya Prakash, the best spine surgeon in Hyderabad. He has handled thousands of sagittal imbalance cases in his 20+ years of experience. He can treat any spinal problem from congenital spinal deformities to adult spinal disorders.