Tandem spinal stenosis
Tandem spinal stenosis (TSS) is an underdiagnosed and poorly recognized condition characterized by narrowing of the spinal canal in at least two regions, most commonly the cervical and lumbar spine, with thoracic involvement often overlooked.
The prevalence of TSS varies widely, ranging from 7.6% to 60%, with higher rates observed in older male patients and those with degenerative spinal changes.
Tandem spinal stenosis has four subtypes—cervico-lumbar, cervico-thoracic, thoraco-lumbar, and cervico-thoraco-lumbar—each varying in prevalence and clinical presentation, underscoring the need for tailored diagnostic approaches.
Common causes include ossification of the posterior longitudinal ligament, ligamentum flavum, and degenerative changes of the spine. Tandem spinal stenosis can manifest as an asymptomatic radiographic finding or progress to severe myelopathy mixed with lower motor neuron signs. The most common is cervico-lumbar, followed by thoraco-cervical, with the other two subtypes being more rare.
The goal of this blog post is not only to inform clinicians on the problem of tandem spinal stenosis but also to give some useful tools on when to suspect its presence. In the next few paragraphs, we will break down some common symptoms that arise from stenosis at each distinct level. Some things will be similar, but some will only appear in that distinct level. The last sentence of each paragraph is going to be the key takeaway.
Cervical myelopathy, associated with cervical spinal stenosis, is characterized by both upper and lower motor neuron involvement. Upper extremity symptoms include difficulties with fine motor skills such as handwriting, buttoning, or typing, as well as intrinsic hand muscle wasting. Patients may exhibit signs such as a positive Hoffman sign, hyperreflexia, and an inverted radial reflex. Sensory findings may include neck pain, radicular pain, and a positive Lhermitte sign. Gait instability is a hallmark of cervical myelopathy and is observed in over 80% of cases. Lower extremity symptoms include hyperreflexia, clonus (defined as more than three beats), weakness (notably in the iliopsoas and quadriceps), and a positive Babinski sign.
Key takeaway: Gait instability and changes to the lower limb reflex or pathological reflexes are also common for thoracic myelopathy, but neck pain, difficulty with fine motor skills, and changes in upper extremity reflexes are only present in cervical stenosis.
Thoracic myelopathy, though less common, is often overlooked due to its symptoms resembling those of lumbar stenosis or even those of cervical stenosis. Patients with thoracic involvement typically present with unsteady gait, hyperreflexia of the lower limbs, and pathological reflexes, often without significant back pain. Missed diagnoses of thoracic myelopathy can result in irreversible spinal cord damage.
Key takeaway: The most common cause of thoracic spinal stenosis is ossification of the posterior longitudinal ligament or ligamentum flavum. If you have a patient with ligament ossification on their lumbar imaging, always refer them for a whole spine MRI.
Lumbar spinal stenosis primarily presents with neurogenic claudication, characterized by pain, weakness, or numbness in the lower extremities that worsens with walking or standing and improves with sitting or bending forward. Additional symptoms include lower back pain radiating to the legs, lower extremity weakness, and hyporeflexia, with muscle atrophy in advanced cases. While lumbar spinal stenosis is often straightforward to diagnose, concurrent thoracic or cervical involvement should be considered in atypical presentations.
Key takeaway: Look for gait disturbances, hyperreflexia, pathological reflexes or difficulty with fine motor skills. Those are not normal signs for lumbar spinal stenosis.
In summary, tandem spinal stenosis is a multifaceted condition that often affects the cervical, thoracic, and lumbar regions. Risk factors for tandem stenosis are a present stenosis at one level and ossification of the posterior longitudinal ligament or ligamentum flavum. My advice is to always do a quick neurological screen with all your lumbar stenosis patients. If they present with ossifications of the spinal ligaments, refer them for a whole spine MRI.
Bai Q, Wang Y, Zhai J, Wu J, Zhang Y, Zhao Y. Current understanding of tandem spinal stenosis: epidemiology, diagnosis, and surgical strategy. EFORT Open Rev. 2022
Peter Mraz, is a physiotherapist working in a private clinic in Slovenia. He focuses on treating and examining patients with musculoskeletal problems, with a particular interest in spinal and knee pathologies. As a strength and conditioning coach and a former European champion in powerlifting, I bring a unique approach to rehabilitation, blending performance optimization with evidence-based care.
