Written by: Vihan DeSilva with Dr. Nabil Ebraheim
Spinal stenosis is a diagnosis mainly made through history and CT/MRI imaging as physical exam findings can be normal namely in lumbar spinal stenoses. A common finding along with painful extension of the spine and decreased lumbar lordosis is narrowing of the spinal foramina, but diagnosis is made when patients present with neurogenic claudication and/or cervical myelopathy. The cause may be congenital or acquired through, for example, endocrinopathies, calcium metabolism disorders, inflammatory diseases, and infectious diseases.1,2 There are other diseases that produce similar symptoms that should be considered in the differential diagnosis of spinal stenosis including metastatic disease, hip disease, peripheral neuropathy, disc herniation, and vascular disease/ vascular claudication.2 The rest of this article will be a discussion on how to differentiate spinal stenosis from these other conditions.
Patients’ pain may be metastatic if it is constant and worse at night or is unresolved even after previous attempts at treatment. Metastatic origin of pain should also be considered in patients who have a cancer/ cancer treatment history or experience fatigue, malaise, unintentional weight loss, or nonspecific symptoms.2,3
Distinguishing hip disease (ie. osteoarthritis) pain from lumbar stenosis pain can be challenging because the two ailments can coexist in a condition known as hip-spine syndrome. The location of the pain can be helpful in identifying the primary pain generator: hip pain can be felt in the groin, lateral hip, posterior hip, or near the spine and SI joint. Internal rotation of the hip can also be compromised in hip disease.2,4 Another way to isolate the pain generator is to inject the hip with steroid and observe. Worsening symptoms could indicate pain coming from lumbar stenosis. However, increased activity of the patient may also cause pain in related structures after the initial injection if it was successful in treating pain from underlying hip osteoarthritis.2
Peripheral neuropathy can also coexist with lumbar stenosis and may further complicate the differential diagnosis of spinal stenosis. EMG studies could aid in discerning stenosis from peripheral neuropathy and motor neuron disease.5 Certain clinical findings may also be useful. Bilateral burning foot pain at night is a distinguishing feature of peripheral neuropathy whereas unilateral leg pain with activity that is relieved by sitting is characteristic of lumbar stenosis/ radiculopathy. Additionally, sensory testing that demonstrates a dermatomal pattern indicates a problem in the spinal root whereas a glove and stock pattern would hint towards peripheral neuropathy.1,2
Disc herniation should also be considered against spinal stenosis as a possible source of pain. Location of pain can once again help in identifying the correct source. According to one comparative study, herniations tend to produce leg pain in the anterior thigh, anterior knee, and shin whereas posterior knee pain was common with stenosis.6 Furthermore, characteristics of stenosis include bilateral, nonspecific leg pain that is generally above the knee and rarely produces a positive straight-leg test. In contrast, herniation causes unilateral pain along the dermatome of the affected nerve root along with a positive straight-leg test.2
Vascular disease should be ruled out as well when considering a spinal stenosis diagnosis. One main distinguishing principle is that vascular disease produces vascular claudication whereas spinal stenosis produces neurogenic claudication. These two different types of claudication have different clinical sequelae. For instance, the distance a patient can walk before feeling symptoms is more variable with neurogenic claudication than with vascular claudication and uphill walking is better tolerated only with neurogenic claudication. Sitting attenuates neurogenic claudication symptoms whereas both sitting and standing still may ease vascular claudication symptoms.7 Vascular pain travels from distal sites to proximal ones whereas neurogenic pain goes from proximal to distal. Unlike vascular claudication, bilateral pedal pulses are normal with neurogenic claudication. Unlike spinal stenosis, vascular disease may produce lower extremity ulcers, hair loss, edema, and skin changes.2 Lastly, postural adjustments, such as flexion of the spine, ease stenosis claudication symptoms due to relief of pressure on the nerve roots. This is not true in vascular disease. This is also why a bicycle test relieves stenosis pain while making vascular pain worse.8
Other rarer considerations include spinal arteriovenous malformations, tumors of the cauda equina, and differential diagnosis of myelopathy (ALS, multiple sclerosis, or subacute combined degeneration).1 Once a spinal stenosis diagnosis is made, the condition can be managed non-surgically with drugs, physiotherapy, and injections or surgically through decompression, spinal fusion, or interspinous spacer devices.9 Evidence is still being gathered on effectiveness and outcomes for all these non-surgical and surgical treatment options though.
References
1. Melancia JL, Francisco AF, Antunes JL. Spinal stenosis. Handb Clin Neurol. 2014;119:541-9.
2. Ebraheim N. Differential Diagnosis of Spinal Stenosis [Internet]. Toledo (OH): University of Toledo Medical Center, Department of Orthopedic Surgery; 2021 Jun 25. Available from: https://www.youtube.com/watch?v=eYxPmrnfjfA&ab_channel=nabilebraheim.
3. Dodwad SM, Savage J, Scharschmidt TJ, Patel A. Evaluation and treatment of spinal metastatic disease. Cancer Treat Res. 2014 Jul 29;162:131-50.
4. Brown MD, Gomez-Marin O, Brookfield KF, Li PS. Differential diagnosis of hip disease versus spine disease. Clin Orthop Relat Res. 2004 Feb;419:280-4.
5. Plastaras CT. Electrodiagnostic challenges in the evaluation of lumbar spinal stenosis. Phys Med Rehabil Clin N Am. 2003 Feb;14(1):57-69.
6. Rainville J, Lopez E. Comparison of radicular symptoms caused by lumbar disc herniation and lumbar spinal stenosis in the elderly. Spine (Phila Pa 1976). 2013 Jul 1;38(15):1282-7.
7. Genevay S, Atlas SJ. Lumbar spinal stenosis. Best Pract Res Clin Rheumatol. 2010 Apr;24(2):253-65.
8. Binder DK, Schmidt MH, Weinstein PR. Lumbar spinal stenosis. Semin Neurol. 2002 Jun;22(2):157-66.
9. Lurie J, Tomkins-Lane C. Management of lumbar spinal stenosis. BMJ. 2016 Jan 4;352:h6234.
