Research Review By Dr. Jeff Muir©

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Date Posted:

April 2020

Study Title:

SHADES of grey – The challenge of ‘grumbling’ cauda equina symptoms in older adults with lumbar spinal stenosis

Authors:

Comer C, Finucane L, Mercer C & Greenhalgh S

Author's Affiliations:

Leeds Community Healthcare NHS Trust, UK; Sussex MSK Partnership, UK; Western Sussex Hospitals NHS Foundation Trust, UK; Bolton Foundation Trust, UK

Publication Information:

Musculoskeletal Science and Practice 2020; 45: 102049. doi: 10.1016/j.msksp.2019.102049.

Background Information:

Cauda equina syndrome (CES), a medical emergency when presenting in a younger population, is also a potentially significant consequence of lumbar spinal stenosis (LSS) in older patients. Recent estimates suggest that up to 60% of adults older than 65 years of age may display MRI evidence of LSS, with or without corresponding symptomatology (2). It is reasonable therefore, that as the population ages, the prevalence of CES secondary to LSS will also increase (1). Regardless of onset, the symptoms of LSS present classically as neurogenic claudication, encompassing a range of symptoms such as aching, cramping, tingling and heaviness which are worsened with walking and lessened with sitting (3). These symptoms are generally attributed to transient ischemia of the lumbosacral/cauda equina nerve roots due to a combination of mechanical compression, nerve root edema and/or venous congestion – resulting from stenosis in the lumbosacral spinal canal (4).

The most concerning symptoms of cauda equina nerve root compression include urinary and/or fecal incontinence, loss of function of the legs, sexual dysfunction and sensory loss in the saddle and/or lower legs (5-7). These symptoms, while commonly screened for in younger patients, are rarely reported in the literature relating to patients suffering from LSS and can present as complications of age-related conditions in the older population, confounding the diagnosis of CES in this cohort. Recognition of these symptoms in an older population remains challenging and can have devastating consequences for the patient if not properly identified.

These authors summarized the evidence to identify the challenges and gaps in the literature regarding CES in older adults with LSS.

Summary:

Acute or Slow Onset:
In patients under age 50, cauda equina syndrome (CES) presents classically as acute onset, severe back pain and sciatica with bladder/bowel dysfunction, reduced sensation in the saddle, or sexual dysfunction, caused most often by compression of the cauda equina nerve roots (L2-S5) by a herniated disc (8). This presentation represents a medical emergency which, if not managed properly, can lead to catastrophic consequences for patients and significant medicolegal consequences for clinicians. Urgent, same-day surgical treatment generally resolves symptoms and can prevent permanent disability and incontinence.

In older patients with LSS, chronic CES may present as a more gradual onset characterized by recurrent and increasing low back pain with insidious onset of unilateral or bilateral lower limb sensory disturbance and/or motor weakness. As opposed to the potentially acute pathophysiology of lumbar disc herniation associated with CES in a younger population, in the older cohort, it is the gradual compromise of the spinal canal associated with LSS that results in a mechanical compression of the affected nerve roots, causing symptom onset. Clinicians must be aware that in the older patients with LSS, the symptoms of CES may present in a non-traditional manner, making diagnosis more difficult.

Complexity of Clinical Symptoms:
Diagnosis of chronic CES in an older population is made more difficult due to the fact that the presentation of CES may mimic symptoms commonly associated with other age-related conditions. Bladder and bowel dysfunction, saddle anaesthesia and sexual dysfunction are all associated with CES, BUT can also be associated with neurological, anatomic and biochemical age-related changes in bladder and lower urinary tract function. Infection, post-surgical complications and pelvic organ diseases also represent causes of CES-like symptoms. In post-menopausal women, estrogen deprivation can also be a contributory factor (9).

In males, lower urinary tract symptoms are also commonly accompanied by erectile dysfunction, a common symptom of CES. Similarly, saddle sensory changes may be caused by lesions associated with neurodegenerative pathologies, neoplasms and tumours (10). The presence of symptoms indicative of chronic CES may easily mimic symptoms associated with typical age-related conditions. As such, clinicians need to be keenly aware of the possible differential diagnoses.

Diagnosis and Management:
In general, MRI imaging is the gold standard when chronic CES is suspected. However, with no standardized system for interpreting and reporting on LSS on MRI (11), the specificity of MRI for diagnosing LSS may be low (12, 13). Further, the correlation between imaging findings and symptoms/disability is poor (14, 15), with stenosis often noted on imaging when no symptoms are present (13). Further, the degree of stenosis is only weakly correlated to the presence of bladder dysfunction, with no consensus on what degree of stenosis may cause this issue.

Management of chronic, “grumbling” CES symptoms remains unclear. Some have suggested that the slow onset symptoms do not require emergency treatment, but should instead be monitored for progression (15). Others suggest that early surgery to decompress the cauda equina and prevent long-term bladder damage should be undertaken (16), even though such surgery is successful in only 40% of patients (5).

In general, symptoms indicative of CES that present rapidly (i.e. over hours or days) should be addressed with immediate/emergency imaging. Slow-developing symptoms (i.e. over the course of weeks) should be imaged urgently (as soon as possible, but not an emergency), while routine imaging is sufficient for symptoms that have developed over the course many months.

Clinical Application & Conclusions:

As the prevalence of LSS grows in the aging population, clinicians must remain aware of the potentially serious consequences of symptoms related to bladder, bowel or lower limb dysfunction that could be indicative of a non-acute presentation of CES, while maintaining awareness of the potential age-related morbidities that could result in presentation of similar symptoms. The authors recommend a “safety first” approach, with the clinician taking a reasoned and careful approach to interpretation of symptoms. In a chiropractic practice setting, the threshold for referral should remain appropriately low to serve the best interest of the patient and the clinician.

Study Methods:

The authors present a narrative review, discussing the relevant pathological and treatment considerations regarding chronic onset CES.

Study Strengths / Weaknesses:

Strengths:
  • This is a clinically relevant and important topic.
  • The authors offered a comprehensive discussion and detailed information regarding differential diagnoses.
Weaknesses:
  • This was a narrative review that did not provide data or pooled data analysis.
  • Some citations may be considered out of date. More relevant citations would be helpful in future updates.

Additional References:

  1. Ishimoto Y et al. Prevalence of symptomatic lumbar spinal stenosis and its association with physical performance in a population-based cohort in Japan: the wakayama spine study. Osteoarthritis Cartilage 2012; 20(10): 1103–1108.
  2. Haig AJ et al. Spinal Stenosis, Back Pain, or No Symptoms at All? A Masked Study Comparing Radiologic and Electrodiagnostic Diagnoses to the Clinical Impression. Arch Phys Med Rehabil 2006; 87(7): 897–903.
  3. Genevay S, Atlas SJ. Lumbar spinal stenosis. Best Pract Res Clin Rheumatol 2010; 24(2): 253–265.
  4. Rydevik B. Neurophysiology of cauda equina compression. Acta Orthop Scand 1993; 64(Suppl 251), 52–55.
  5. Deen HG et al. Assessment of bladder function after lumbar decompressive laminectomy for spinal stenosis: a prospective study. J Neurosurg 1994; 80(6): 971–974.
  6. Kawaguchi Y et al. Clinical symptoms and surgical outcome in lumbar spinal stenosis patients with neuropathic bladder. J Spinal Disord 2001; 14 (5): 404–410.
  7. Konno S et al. A diagnostic support tool for lumbar spinal stenosis: a self-administered, self-reported history questionnaire. BMC Muscoskelet Disord 2007; 8: 102.
  8. Fraser S, Roberts L, Murphy E. Cauda equina syndrome: a literature review of its definition and clinical presentation. Arch Phys Med Rehabil 2009; 90(11): 1964–1968.
  9. Rosier P et al. Is Detrusor Instability in Elderly Males Related to the Grade of Obstruction? Neurourol Urodyn 1995; 14(6): 625–633.
  10. Deboo A. Numbness and paresthesias in the elderly. J Geriatr Aging 2003; 6(6): 11.
  11. Schroeder GD, Kurd MF, Vaccaro AR. Lumbar spinal stenosis: how is it classified? J Am Acad Orthop Surg 2016; 24(12): 843–852.
  12. Wassenaar M et al. Magnetic resonance imaging for diagnosing lumbar spinal pathology in adult patients with low back pain or sciatica: a diagnostic systematic review. Eur Spine J 2012; 21(2): 220–227.
  13. Lurie J, Tomkins-Lane C. Management of lumbar spinal stenosis. BMJ 2016; 352: h6234.
  14. Kalichman L et al. Spinal stenosis prevalence and association with symptoms: the framingham study. Spine J 2009; 9(7): 545–550.
  15. Gleave JR, Macfarlane R. Cauda equina syndrome: what is the relationship between timing of surgery and outcome? Br J Neurosurg 2002; 16(4): 325–328.
  16. Gandhi J et al. Neuro-urological sequelae of lumbar spinal stenosis. Int J Neurosci 2018; 128(6): 554–562.