Minimally Invasive Surgery

General Overview

Scoliosis refers to a curvature of the spine to the side. True scoliosis is also associated with a twisting or rotation of the spine. Scoliosis is generally not painful. When a person is viewed from the front or from behind, the spine is normally straight. The shoulders and pelvis are normally level and parallel to the ground when standing. When a person bends forward, the ribs appear level and symmetric.

With scoliosis, alterations in this normal anatomy occur. The shoulders may be uneven (asymetric) with one shoulder being higher than the other. The pelvis may also be uneven, resulting in skin creases on one flank and uneveness in the hem-line or belt line. With rotation, one rib protrudes further from the body than the other. Curvature of the spine may develop as a single curve to a side (shaped like the letter C) or as two curves, side to side, (shaped like the letter S).


Scoliosis can occur in the mid (thoracic) spine, the low (lumbar) spine, or both areas at the same time. The severity of the scoliosis is measured in degrees by comparing the curves to “normal” angles. Curves can range in size from as little as 10 degrees to severe cases of more than 100 degrees. The amount of curve in the spine helps your doctor decide what treatment to suggest.

Adolescent Idiopathic Scoliosis:
While scoliosis can be diagnosed in infants and young children, most cases of scoliosis are first discovered and treated in older children and adolescents (ages 10-15), particularly during puberty when the curvature becomes more noticeable. When an adolescent has scoliosis with no known cause, doctors call the condition adolescent idiopathic scoliosis. This form of scoliosis can affect a child who is healthy and not having nerve, muscle, or other spine problems. It is the most common form of spinal deformity doctors see, affecting about three percent of the general population.

Adult Scoliosis:
Scoliosis that occurs (or is discovered) after puberty is called “adult scoliosis.” Adult scoliosis can be the result of untreated or unrecognized childhood scoliosis, or it can arise during adulthood. The most common cause of adult scoliosis is usually degeneration.

Degenerative Scoliosis:
Degenerative adult scoliosis occurs when the combination of age and deterioration of the spine leads to the development of a scoliosis curve in the spine. Degenerative scoliosis usually starts after the age of 40. In older patients, particularly women, it is also often related to osteoporosis (loss of bone mass). The osteoporosis weakens the bone, making it more likely to deteriorate. The combination of these changes causes the spine to lose its ability to maintain a normal shape. The spine begins to “sag” and as the condition progresses, a scoliotic curve can slowly develop.

Minimally spine surgery procedures approach the spine from the front (anterior), back (posterior), side (lateral), or back and side (posterolateral). Procedures such as those listed below share the same surgical goals:

The interbody device, such as a Titanium cage or PolyEtherEther Ketone (PEEK) spacer, is implanted into the disc space. Bone graft is packed into and around the device to stimulate spinal fusion.

  • ALIF provides access to the spine through the abdomen. This procedure is often combined with posterior fusion and instrumentation for better spinal fixation.
  • DLIF / XLIF provides access to the spine through the side of the body. This procedure involves a transpsoas approach, which means the surgeon accesses the spine through the psoas muscle; a long muscle on either side of the lumbar spine.
  • TLIF provides access to both sides of the disc through the intervertebral foramina, small passageways through which nerves exit the spinal canal. An interbody device, such as a cage or spacer is implanted into the disc space from one side of the spine. Pedicle screws and rods, with additional bone graft, secure the back (posterior) section of the spine. TLIF fuses the front and back sections of the spine.

    Above: Patient has minimal scarring after DLIF procedure

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            Minimal Scarring After Surgery                                          MIS for scoliosis; before and after x-rays