For posterior spinal decompression surgery to aggravate Spondylolysis or Spondylolisthesis, signs/symptoms of Spondylolysis or Spondylolisthesis should occur within 10 years of the surgery.
For posterior spinal decompression surgery to cause Spondylolysis or Spondylolisthesis, the surgery may occur any time before clinical onset of either condition.
The most commonly used grading system for spondylolisthesis is the one proposed by Meyerding in 1947. The degree of slippage is measured as the percentage of distance the anteriorly translated vertebral body has moved forward relative to the superior end plate of the vertebra below. Classifications use the following grading system:
Several theories on the causes of pain in patients with spondylolytic spondylolisthesis have been proposed. These include isthmic defect, the intervertebral disc, adjacent facet joint and stenotic changes which have been implicated in the causation of back and sciatica syndrome. Histological studies have demonstrated the presence of nociceptive fibres in the pars defect. Communication between the facet capsule and the isthmic defect which appear to occur because of capsular tears. Kirkaldy-Willis has drawn attention to the lateral recess and foraminal stenosis with entrapment of the exiting nerve by the pars interarticularis. Fibrosis around the exiting nerve following laminectomy and fusions in patients with spondylolisthesis provides another source of pain.
Clinical decision involving a radiographic series of the spine is based on medical necessity, as per criteria for radiographic exam. Diagnosis of spondylolisthesis does not, in and of itself, require radiographic evaluation. Determination of the need for ordering or exposing radiographs requires prior assessment of the patient’s history, subjective findings, objective findings, and review of other available diagnostic testing results.
In Spondylolisthesis with a significant slip, a step-off at the lumbosacral junction is palpable, motion of the lumbar spine is restricted, and hamstring tightness is evident on straight leg raising. As the vertebral body displaces anteriorly, the individual assumes a lordotic posture above the level of the slip to compensate for the displacement. Adults may have objective signs of nerve root compression, such as motor weakness, reflex change, or sensory deficit. These signs are seldom seen in children.
There are multiple classification of lumbar and lumbo-sacral spondylolisthesis. As such clinically, in the adults the distinction between isthmic and congenital spondylolisthesis is considered to be theoretical and anatomic (Ref). We have used the term lytic spondylolisthesis in adults who have presented with lytic defect in the pars to distinguish them from patients with attenuated pars interarticularis and patients with degenerative, post surgical, post traumatic, pathological spondylolisthesis and that occurring in patients with widespread or localised bone.
In Spondylolysis, symptoms are often absent. Defects are then discovered only incidentally on x-ray made for other purposes. In Spondylolisthesis, injury may aggravate (permanently worsen) any symptoms, but rarely does a single injury cause symptoms in a person who previously had none. Symptoms generally begin insidiously during the second or third decade as an intermittent dull ache in the lower back, present with increasing frequency during walking and standing. Later, pain may develop in the buttocks and thighs, and still later unilateral sciatica may develop.
Spondylolysis and Spondylolisthesis usually cause no symptoms in children; however, many seek medical evaluation because of a postural deformity or gait abnormality. Pain most often occurs during the adolescent growth spurt and is predominantly backache, with only occasional leg pain. Symptoms are exacerbated by high activity levels or competitive sports and are diminished by activity restriction and rest. The back pain probably results from instability of the affected segment, and the leg pain is usually related to irritation of the L5 nerve root.
There may be no objective signs in Spondylolysis, or in first or second degree Spondylolisthesis. The finding of Spondylolysis on x-ray in an adult is likely to be incidental, and not the cause of back pain if that pain did not commence in childhood or adolescence. Tightened hamstrings are present in the majority of those who are symptomatic. Tenderness and spasms of the paravertebral muscles may be present at the level of the vertebral defect and surrounding segments. Pain may be induced and increased by certain movements.
Although this subtype has a strong hereditary tendency, it makes up only half of the dysplastic group. The elongated pars (subtype b) is believed to result from micro fractures that heal with an elongated pars rather than from a lytic lesion. Acute pars fractures (subtype c) always result from significant trauma; these are rare and most frequently occur with Spondylolysis rather than with Spondylolisthesis.
The lytic (subtype a) results from the separation or dissolution of the pars. The incidence of this type of Spondylolisthesis increases from less than 1 percent in children 5 years of age to 4.5 percent in children 7 years of age. The remaining 0.8 to 1 percent increase occurs between the ages of 11 to 16 years, presumably because of stress fractures caused by athletic activity. Extension movements of the spine, with lateral flexion, can increase the shearing stress at the pars interarticularis and result in Spondylolysis.