REIDER PART 2
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Charter 9_Lumbar Spine 339

Figurę 9-4. Lateral aspcct of the lumbar spinc. A, Normal alignmcnt. B, Hyperlordosis. C, Fiat back deformity. (C, From Rothman RH, Simeone FA. The Spine, 3rd ed. Philadelphia, WB Saunders, 1992, p 905.)

known as swayback, results in increased prominence of the buttocks. It is usually associated with tlexion contrac-ture of the hips, as described in Chapter 5, Pelvis, Hip, and Thigh.

Decreased Lumbar Lordosis. Decreased lumbar lordo-sis is often a temporary, reversible deformity related to pain and associated muscle spasm. Conditions in which pain is exacerbated by extension of the lumbar spine, such as spondylolysis, may be associated with a reflexive decrease in lumbar lordosis. Ankylosing spondylitis may produce a morę rigid decrease in lumbar lordosis.

Lumbar flatback syndromc dcscribes a rigid lumbar spinc in which the normal lordosis has been complctely lost (see Fig. 9-4C). Compression fractures that result in anterior wedging of the lumbar vertebral bodies can produce lumbar flatback syndromc. Advanced degeneration of the lumbar intervertcbral disks may also result in this same deformity. Lumbar flatback syndrome may also occur following a long thoracolumbar spinał fusion for correction of scoliosis. Older surgical instrumentation Systems tended to allow for only coronal piane deformity correction and straightened the spine in the sagittal piane, leading to a flatback deformity.

Gibbus. A gibbus is a sharp, angular kyphotic deformity often noticed by the protruding spinous process at the apex of the deformity. Gibbus is classically associated with tuberculosis of the spine. In this case, the infection destroys the anterior aspect of a vertebral body and the adjacent disk space, resulting in a localized collapsc of the anterior portion of the vertebral column. Vertebral body collapse due to tumors, other infections, or fractures may also produce a gibbus.

Gait

Although gait evaluation is not always considered an inte-gral part of a lumbar spine examination, pain or deformity associated with certain conditions of the lumbar spine may produce characteristic gait abnormalities. A classic example is the gait abnormality that may be associated with sciatica. Sciatica is most commonly caused by a herniated disk at the L5-S1 or the L4-L5 interspace compressing a nerve root that feeds into the sciatic ncrve. Because knee extension and hip flexion place further ten-sion on the painful sciatic nerve, the patient with sciatica may attempt to walk with the hip morę extended and the knee morę flexed than normal. In addition, the patient may display an antalgic gait, putting as little weight as possible on the affected side and then ąuickly tran sfer ring the weight to the unaffected side.

The ability to toe walk and heel walk may also be used to screen for lumbar radiculopathy. These tests allow the examiner to quickly screen for radiculopathy related to the most common lumbar disk herniations. This method also allows the involved muscles to be tested with considerably higher loads than are exerted during manuał testing of the same muscle groups.