Spondylolisthesis

One vertebra has slipped forward relative to the one below, most commonly at the lowest lumbar level. It is graded by how far the slip has gone, from grade I through grade IV.

The grade correlates poorly with symptoms. Many people with a grade I or II slip have no pain at all, and some with small slips have significant symptoms. Treatment follows the symptoms and function rather than the X-ray.

Isthmic spondylolisthesis follows a stress fracture in a part of the vertebra, often developing in adolescence in sports involving repeated back extension — gymnastics, cricket bowling, diving.

Degenerative spondylolisthesis develops later in life from facet joint and disc wear, most often at L4-L5, and is more likely to be associated with spinal stenosis and leg symptoms.

Progressive strengthening of the trunk and hip muscles, aimed at better control of the slipped segment. The trials behind it are small: in one, 44 people with chronic back pain and spondylolysis or spondylolisthesis had less pain and disability after a 10-week programme of specific deep trunk-muscle exercises, with the benefit maintained at 30 months, while the comparison group showed no significant change 4. Movement retraining for the tasks that provoke symptoms. Activity modification rather than avoidance of activity.

Loaded extension and repeated end-range extension are usually avoided, particularly in isthmic cases, because they load the defect directly.

Progressive neurological deficit. Significant leg symptoms from associated stenosis that have not responded to a proper conservative programme. Progression of the slip on serial imaging in a young patient.

In adults, the evidence on fusion for pain alone is mixed. In a randomised trial of adults with isthmic spondylolisthesis, at least a year of pain and severely restricted function, fusion improved pain and function more than an exercise programme at two years 5. After an average of nine years, the groups differed only in how patients rated their overall result 6. A properly delivered exercise programme should be tried first.

Many people have a slip visible on imaging and no symptoms at all: in a community study of 188 adults aged 40 to 80 who had CT scans, having a slip was not associated with low back pain 2. The grade also correlates poorly with how much pain someone has. In adults a slip can progress slowly, but this does not track symptoms: over 10 to 18 years, 34% of 145 people with the degenerative type showed progression, with no correlation between progression and changes in symptoms 3.

What tends to produce symptoms is the instability and the muscular fatigue around it, which is why trunk and hip strengthening changes pain even though it cannot change the slip.

Usually, yes. A systematic review of 14 studies of athletes with spondylolysis, the stress fracture behind the isthmic type, found that 92% of those treated conservatively with bracing, sport modification and physiotherapy returned to sport, and 89% returned at their previous level, after an average of 4.6 months 7.

Athletes treated surgically, usually after conservative care had not worked, returned to sport in 88% of cases and to their previous level in 81%, on average at 6.8 months 7. The studies behind these figures are case series, so they are encouraging rather than precise 7. Return is usually staged, with pain-free daily activity first and repeated back-arching movements such as bowling, tumbling or diving reintroduced last, and a young athlete who is still growing is monitored for any increase in the slip.