Spondylolisthesis
Vertebral slippage — Isthmic & degenerative forms
What is spondylolisthesis?
Spondylolisthesis refers to the slippage of one vertebra relative to the one below. Imagine two bricks stacked on top of each other: the upper brick slides slightly forward, creating a step-off. This displacement can narrow the spinal canal, compress the nerves and cause pain.
The slip most commonly occurs at L4-L5 or L5-S1, where the lumbar spine bears the body's weight and undergoes the greatest mechanical stresses. It may remain stable and well tolerated for years, or progress and become symptomatic.
Types & mechanisms
Several forms of spondylolisthesis exist, each with its own mechanism:
• Isthmic (pars defect): a stress fracture of the pars interarticularis (the bony "hinge" that holds the vertebra in place), common in young athletes and often discovered incidentally
• Degenerative: the most common form after 50, caused by disc and joint wear that can no longer "hold" the vertebra in position
• Traumatic: following a vertebral fracture
• Meyerding classification: the slip is graded from I to IV, from minimal (grade I: less than 25%) to severe (grade IV: more than 75%)
Symptoms & Clinical signs
The clinical picture depends on the degree of slippage and associated nerve compression:
• Mechanical low back pain: pain in the lower back, worsened by prolonged standing and physical effort, relieved by rest
• Lumbar stiffness: a feeling of the back being "locked", difficulty straightening up after bending
• Radicular pain: sciatica or cruralgia if the nerves are compressed by the slip
• Neurogenic claudication: difficulty with prolonged walking (as in spinal stenosis) if stenosis is associated
• Asymptomatic forms: many grade I slips are discovered incidentally on X-ray, without any pain
Diagnosis
• Lateral X-rays: the basic investigation that reveals the slip and allows it to be measured (Meyerding classification)
• Dynamic X-rays (flexion-extension): essential to assess whether the slip is "mobile" (unstable) or fixed
• Lumbar MRI: visualises the condition of the discs, nerves and presence of compression
• CT scan: shows a pars defect with great precision and helps plan any surgery
Treatment
The majority of spondylolisthesis cases, especially grade I, are treated without surgery:
Conservative treatment
• Strengthening the "core" muscles: the muscles become the "natural corset" that stabilises the vertebra
• Targeted physiotherapy: proprioception work, core strengthening, hamstring stretching
• Anti-inflammatory drugs and painkillers for acute flare-ups
• Injections: epidural or facet joint, depending on the pain component
Surgical treatment (spinal fusion)
• Indications: disabling pain resistant to medical treatment, persistent nerve compression, or documented progressive slippage
• Technique: fusion involves "locking" the two vertebrae together using screws and an interbody cage, thereby eliminating the abnormal movement
• Outcome: fusion rate above 90%; significant improvement in pain and function
Key figures
5–6%
Of the population has a pars defect, often discovered incidentally
80–90%
Of grade I and II slips respond favourably to conservative treatment
L4-L5 / L5-S1
Most commonly affected levels
Recovery after surgery
After lumbar fusion for spondylolisthesis, patients are encouraged to stand and walk the day after surgery. The hospital stay averages 3 to 5 days. A soft lumbar brace may be prescribed for 4 to 6 weeks to support healing, depending on the initial grade of slippage and bone quality.
Chronic low back pain caused by the slippage typically improves rapidly in the first few weeks. Radicular pain, when present, usually resolves within the first few postoperative days. Daily walking is encouraged from the outset. Driving is generally possible from week 4. A rehabilitation programme begins around week 6, focusing on deep core strengthening and flexibility. Return to work occurs between 2 and 4 months depending on the type of job — earlier for desk-based roles, later for physically demanding occupations. The bone fusion rate exceeds 90% at one year, ensuring permanent stabilisation of the operated segment.
Consultation with Dr Dimitriu
Dr Christian Dimitriu, a neurosurgeon specialising in spine surgery, manages spondylolisthesis in all its forms — isthmic, degenerative or traumatic. During the consultation, he performs a thorough clinical examination (walking test, neurological assessment, segmental instability testing) and reviews all imaging studies. Dynamic X-rays in flexion-extension are routinely requested to evaluate the mobility of the slip.
Dr Dimitriu always favours conservative treatment first: targeted physiotherapy, core muscle strengthening and injections when necessary. Surgery is only considered after prolonged failure of medical management, persistent neurological compression, or documented progressive slippage. If fusion is indicated, he explains the technique, expected benefits and postoperative course in detail, so the patient can make a fully informed decision. Postoperative follow-up is personalised, with regular consultations and radiographic monitoring of fusion progress.
Prevention and lifestyle
Although spondylolisthesis often has a structural component (pars defect or disc degeneration), several measures can limit progression of the slip and prevent painful episodes. Regular strengthening of the deep trunk muscles — transversus abdominis, lumbar multifidus — creates an effective "muscle corset" that stabilises the vertebra. Core exercises, proprioception training and hamstring stretching are particularly beneficial.
Maintaining a healthy weight reduces the mechanical load on the lumbar spine. Repeated hyperextension movements and heavy lifting without proper technique (bending the knees, keeping the back straight) should be avoided. Patients with an incidentally discovered pars defect should have periodic radiographic follow-up to monitor any progression of the slip, even in the absence of symptoms.
Consultations in Île-de-France
Dr Dimitriu practises at 4 facilities in the Paris region (Île-de-France), easily accessible from central Paris: Clinique de l'Yvette (Longjumeau), Hôpital Privé d'Antony, Clinique du Mont-Louis (Les Lilas) and Hôpital Privé de l'Ouest Parisien (Saint-Cloud). See addresses and book an appointment.
Frequently asked questions
Yes, in most cases. Low-impact sports such as swimming, cycling and walking are recommended. Core strengthening exercises are actually beneficial for stabilising the vertebra. However, sports involving hyperextension (gymnastics, diving) or heavy axial loading should be avoided without prior medical advice.
The loss of mobility is very slight because fusion typically involves only one vertebral level. The adjacent segments compensate well. Most patients notice no restriction in everyday activities and enjoy a significantly improved quality of life thanks to the relief of pain.
An urgent consultation is needed if you experience leg weakness, urinary problems (difficulty urinating or incontinence), numbness in the perineal area (cauda equina syndrome) or a sudden severe worsening of pain. Although rare, these signs indicate severe nerve compression requiring prompt treatment.
Yes, the vast majority of patients lead a completely normal life. Many grade I slips are asymptomatic and only require monitoring. A tailored muscle-strengthening programme, good postural habits and regular follow-up are usually sufficient to keep symptoms under control.
Sources: SFCR · Spine (Kalichman et al., 2009) · European Spine Journal.