What is Spondylolisthesis?
A condition in which one vertebra slips forward compared to the bone below. The amount of slip ranges from a few millimetres often asymptomatic to a more significant shift that narrows the foramen where the nerve sits. Graded I–V by the percentage of slip treatment is based on the symptoms rather than the degree of the slip.
Causes
Isthmic — a stress fracture or defect of the pars interarticularis, common in adolescent athletes gymnastics, dance, fast bowling, weightlifting, usually L5–S1 or less commonly L4-L5. Degenerative — age-related wear of the discs and facet joints, typically L4–L5 in adults over 50. Less commonly congenital dysplastic, traumatic, pathologic osteoporosis, Pagets disease, infection, tumour, or post-surgical…
Symptoms
Many are asymptomatic. When symptoms occur mechanical low back pain worse with extension-loading sports and prolonged standing, eased by rest radicular nerve pain into the buttock, leg or foot, often L5 distribution claudicant leg pain with walking that eases on leaning forward tight hamstrings particularly in adolescents reduced lumbar range and a stiff lower back a palpable step in higher-grade slips.
Diagnosis
History onset, sport, family history, bowel/bladder, examination of standing posture, gait, lumbar range of motion, hamstring tightness, neurological function and provocative tests such as single-leg extension often painful in active spondylolysis.
Imaging
Standing X-rays of the lumbar spine are the cornerstone — flexion-extension views also show whether the slip changes with movement to indicate that it is unstable. MRI to assess discs, nerves and any canal compression. CT for bony detail when a pars defect is unclear. CT SPECT bone scan in selected patients to determine if a pars stress reaction is active and likely to benefit from a period of rest and bracing.
Treatment
The great majority are managed without surgery. Activity modification particularly for adolescents with an active pars stress reaction, structured physiotherapy core, gluteal and hip strengthening, hamstring stretching, postural retraining, graded return to sport, medications, and CT-guided steroid injections for radiculopathy. A rigid lumbar brace can settle a hot pars stress reaction in adolescents. Surgery is considered for severe persistent symptoms, progression of the slip, significant nerve compression, or selected high-grade and adolescent slips.