Spondylolisthesis

Young athlete (isthmic): insidious activity-related low back pain, worse on lumbar extension; history of repetitive extension-loading sport (gymnastics, cricket fast bowling, rugby front row, ballet, weightlifting, throwing); marked hamstring tightness; pain on single-leg hyperextension (stork test); palpable step-off in higher-grade slips. Radicular features are typically minimal in low-grade disease.

Older adult (degenerative): mechanical low back pain with neurogenic claudication - bilateral leg heaviness, paraesthesia, or pain on standing or walking, relieved by flexion (sitting, leaning on a trolley). Radicular leg pain is common, classically L5 distribution at L4-L5. Walking-induced symptoms relieved by sitting is the classic story. Lumbar extension may be reduced and posture flexed in advanced cases.

Examination: document L4, L5, and S1 myotomes, dermatomes, and reflexes. L5 radiculopathy is common with L4-L5 degenerative disease; S1 symptoms occur with L5-S1 isthmic disease. Assess perineal sensation and anal tone when cauda equina is a concern.

Differentials: spondylolysis without slip; lumbar disc prolapse (dermatomal symptoms, positive SLR); lumbar spinal stenosis without slip; facet OA (extension- and rotation-driven); SIJ pain; inflammatory back pain (morning stiffness, alternating buttock pain, axial spondyloarthritis per NICE NG65); vertebral fracture (acute pain, focal tenderness, osteoporosis or trauma history).

Per NICE NG59, do not routinely image non-specific low back pain. Image when red flags are present, when serious pathology is suspected, when symptoms persist despite conservative management, or when imaging will change management.

Plain radiographs: standing weight-bearing AP and lateral lumbar spine. The lateral view confirms the slip and allows Meyerding grading by the percentage of vertebral body translation - Grade I (under 25%), II (25-50%), III (50-75%), IV (75-100%), V (spondyloptosis, over 100%). Flexion-extension laterals assess dynamic instability when surgery is being considered. The oblique Scotty dog with a collar (pars defect) sign is a recognised exam trope but is not routinely used in modern UK practice because MRI and CT serve the same purpose without ionising radiation.

MRI is the investigation of choice for nerve root compression, central canal and lateral recess stenosis, and disc disease, and is mandatory before surgical decompression or fusion. MRI with bone marrow oedema (STIR) sequences is the first-line modern investigation for suspected active pars stress reactions in adolescents because it identifies metabolically active healable lesions and avoids ionising radiation (RCR iRefer guidance in young patients).

CT characterises bony detail of established cortical pars defects, articular processes, and any associated traumatic injury better than MRI. Most useful for chronic non-united defects and surgical planning rather than first-line in the active stress phase.

Management is driven by age group, slip grade, slip stability, neurological status, and symptom burden.

First-line conservative management (low-grade Meyerding I-II without significant neurology, the majority of cases):

• •Activity modification: stop the offending extension-loading sport in adolescents until pain settles
• •Physiotherapy: core stability, neutral-spine motor control, gluteal and hamstring conditioning, hip flexor flexibility. Lumbar flexion-biased programmes are often well tolerated. NICE NG59 supports group exercise within a package of care
• •Analgesia per NICE NG59: paracetamol monotherapy is NOT recommended. NSAIDs at the lowest effective dose for the shortest time with GI, renal, and cardiovascular risk assessment. Avoid gabapentinoids, antiepileptics, oral corticosteroids, and benzodiazepines for sciatica. Avoid opioids for chronic sciatica
• •Bracing: in symptomatic adolescents with active pars stress injury or low-grade isthmic slip, an anti-lordotic lumbosacral brace may be considered selectively under specialist supervision. NICE NG59 advises against belts or corsets for adult LBP

Most low-grade adolescent isthmic and adult degenerative slips can be managed conservatively with structured rehabilitation over 3-6 months.

Injections:

• •Epidural local anaesthetic and steroid (NG59): consider for acute severe sciatica. NG59 advises AGAINST epidural for neurogenic claudication from central canal stenosis - so not a treatment in the typical older adult degenerative spondylolisthesis with claudication
• •Fluoroscopically guided pars injection: occasionally used in elite athlete pathways diagnostically and therapeutically. Specialist use only

Surgical referral indications:

• •Cauda equina syndrome: emergency referral with same-day MRI
• •Progressive motor deficit
• •High-grade slip (Meyerding III-V), particularly in adolescents
• •Documented progression on serial imaging
• •Persistent disabling leg-dominant symptoms (radiculopathy or neurogenic claudication) despite 3-6 months of structured conservative management with imaging-confirmed correlation
• •Severe neurogenic claudication limiting walking distance in degenerative disease

Surgical principles:

• •Surgery primarily relieves leg-dominant symptoms by decompressing nerves; back pain relief is less reliable. NG59 cautions against fusion for isolated low back pain
• •Decompression alone (laminectomy, foraminotomy) for selected stable degenerative cases without instability
• •Decompression with instrumented fusion (posterolateral, PLIF, TLIF) where there is instability, deformity, foraminal stenosis, high-grade slip, or where the decompression itself would create instability
• •High-grade adolescent slip: fusion in situ is often preferred over aggressive reduction because of the risk of iatrogenic L5 nerve root stretch injury
• •Smoking cessation before fusion improves union rates. VTE assessment per NICE NG89 for post-operative immobilisation

Conservative pathway:

• •Phase 1 (0-6 weeks): symptom control, activity modification, gentle pain-relieving mobility, neutral-spine awareness
• •Phase 2 (6-12 weeks): progressive core stability (transversus abdominis, multifidus), gluteal and hamstring conditioning, hip flexor mobility, lumbar flexion-biased exercise where tolerated
• •Phase 3 (3 months onwards): progressive load, sport-specific reconditioning, technique modification (avoiding extreme lumbar hyperextension), graded return to sport

Return to running typically 8-12 weeks for low-grade slips; return to extension-loading sport often 3-6 months and only when pain-free with full functional capacity.

Post-operative pathway (after fusion):

• •Early mobilisation per surgeon
• •Avoid heavy lifting, twisting, and impact for typically 3-6 months
• •Progressive core and global strengthening from around 6 weeks
• •Return to running often 4-6 months; return to contact or extension-loading sport often 9-12 months, dependent on imaging confirmation of fusion

Address contributors throughout: training load, technique, weight, bone health, smoking cessation.

• •Wiltse-Newman classification (1976): six aetiological types (dysplastic, isthmic, degenerative, traumatic, pathological, iatrogenic) - the standard UK and international framework.
• •Meyerding classification (1932): slip percentage I-V on standing lateral radiograph; drives surgical referral thresholds and prognosis.
• •NICE NG59 (2016, updated 2020): UK red flag, imaging, and management framework for back pain and sciatica in over-16s. Specifies what NOT to prescribe and that fusion is not indicated for isolated low back pain.
• •BASS (British Association of Spine Surgeons) UK guidance: surgical decompression and fusion thresholds for degenerative spondylolisthesis and high-grade adolescent slips.
• •RCR iRefer: imaging guidance recommending MRI first-line in young patients with suspected spondylolysis or spondylolisthesis to avoid ionising radiation.
• •NICE NG65 Spondyloarthritis: referral pathway when inflammatory back pain features are present.

• •Spondylolisthesis is anterior vertebral translation. Isthmic in young athletes (commonly L5-S1, pars defect); degenerative in older adults (classically L4-L5, female predominance).
• •Wiltse-Newman six types: dysplastic, isthmic, degenerative, traumatic, pathological, iatrogenic. Meyerding I-V grades the slip percentage on standing lateral X-ray. Grades III-V usually warrant surgical opinion.
• •Classic young athlete: extension-related back pain, marked hamstring tightness, positive stork test (suspicion-raising, not diagnostic - imaging needed). Classic older adult: neurogenic claudication relieved by flexion or sitting.
• •Imaging: standing lateral X-ray for slip and grading; MRI with STIR is first-line in adolescents for active pars lesions (avoids radiation per RCR iRefer); CT for chronic bony detail and surgical planning. The oblique Scotty dog with collar is a classic exam trope but no longer routine UK practice.
• •NICE NG59 do-not-prescribe list is heavily tested: no paracetamol alone, no gabapentinoids or antiepileptics for sciatica, no oral steroids or benzodiazepines for sciatica, no belts or corsets for adult LBP, and fusion is NOT for isolated low back pain. Epidural for sciatica only - not for stenosis-related claudication.
• •High-grade adolescent slip: in situ fusion is often preferred over aggressive reduction because of the risk of iatrogenic L5 nerve root stretch. Cauda equina is a same-day surgical emergency.