Spinal problems are increasing rapidly nowadays, mainly due to our sedentary lifestyle and other postural and physical habits. Most of the spinal problems can be treated by non-surgical procedures, but sometimes surgery is the only option that includes the use of specially designed spinal implants.
Conditions requiring spinal implants:
These implants can correct deformities, reduces pain, neurological defect and helps to stabilize the spine. Conditions requiring spinal implants include disc slip, degenerated disc, spinal tumor, spondylosis, fracture of the vertebrae, posterior rami syndrome and spinal instability such as scoliosis and kyphosis. In the cervical spine, most common problems are compressed nerve root or herniated disc while in lumbar spine kyphosis and scoliosis are the main problems. All these issues can be corrected by spinal implants.
The spinal implants are made from titanium, alloy or steel which is stainless, and some from non-metals (plastics). They are especially designed in various shapes and sizes so that they may fit in different patients of various ages and sizes.
Research is being done in this field to further refine the implants that work more accurately. With the invention of screw, rods and hooks, surgeons are able to treat deformed spine in all the three dimensions. The specific type of plates and small sized implants are being designed for spinal fusion and for children respectively.
Types of Spinal Implants:
1) Fusion implants:
Fusion implants are used with bone grafts and it includes; rods, screws, plates, hooks and cages.
Rods have been used since the advent of the implants. The purpose of these rods is to make the affected segments of the spine non-mobile for the accurate alignment of the spine. Rods are made up of titanium or stainless steel, but it is flexible, which allows the surgeon to fit the rod according to the contour of the spine.
These are called pedicle screws because they are fixed in the pedicles of the vertebra. They are used for the lumbar segments, but because of the ongoing progress in this field, it is also being used for thoracic spine. Rods should be fixed according to the contour of the spine and for that purpose screws are used as they provide anchorage points for rods. In this way, it promotes fusion and removes deformities.
Hooks are used with rods; they help in anchoring them and other implants to the vertebrae.
Plates are used with screws so that it may be held in place in a vertebra. Plates are adjusted according to the size of the patient and for that purpose, contouring tool may be used.
Cages are used mostly for collapsed disc and nerve root impingement. These are small devices. These are placed between vertebrae and a bone graft may be packed between them to promote the growth of the affected vertebral column.
2) Non-fusion implants:
These are not combined with bone grafts. Examples are; Growth-sparing devices and artificial discs. These growth sparing devices are used in children who have the growing skeleton.
It is better to use low-volume and low-profile implants so that they are not visible through the skin and there is no post-operative pain. Titanium is better as it is light and can be seen on MRI. Progress is being made in this field so that better results can be obtained.