Association Between Chiropractic Spinal Manipulation and Cauda Equina Syndrome in Adults with Low Back Pain: Retrospective Cohort Study of US Academic Health Centers

Association Between Chiropractic Spinal Manipulation and Cauda Equina Syndrome in Adults with Low Back Pain: Retrospective Cohort Study of US Academic Health Centers

PLOS (Pubic Library of Science) ONE
March 11, 2024; Vol. 19; No. 3; Article e0299159

Robert J. Trager, Anthony N. Baumann, Jaime A. Perez, Jeffery A. Dusek, Romeo-Paolo T. Perfecto, Christine M. Goertz; from University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine (Cleveland, Ohio), Duke University School of Medicine, Northeast Ohio Medical University. This study cites 68 references.

“The study hypothesis was that there would be no increase in the risk of CES [cauda equina syndrome] in adults with LBP following CSM [chiropractic spinal manipulation] compared to a propensity-matched cohort following physical therapy (PT) evaluation without spinal manipulation over a three-month follow-up period.”

“The present study was conducted because prior case reports and medicolegal cases described an onset of CES following CSM, yet there was no adequately powered and designed study to examine this potential association.”

The study used 67,220 patients in each cohort (DC and PT), for a total of 134,440 subjects, with a mean age of 51 years.

KEY POINTS FROM THIS ARTICLE:

1) “The cauda equina is a bundle of nerve roots arising from the spinal cord at the upper lumbar spine.”

2) “Compression of these nerve roots, typically by a disc herniation, can cause cauda equina syndrome (CES).”

3) “Signs and symptoms of CES include one or more of the following:”

• Bladder/bowel dysfunction
• Reduced saddle area sensation
• Sexual dysfunction
• Potential low back pain (LBP) or lower extremity symptoms

4) “CES with neurological deficits is a medical emergency and surgical intervention is recommended within 48 hours to prevent permanent damage.”

5) “Cauda equina syndrome (CES) is a lumbosacral surgical emergency that has been associated with chiropractic spinal manipulation (CSM) in case reports.”

• “However, identifying if there is a potential causal effect is complicated by the heightened incidence of CES among those with low back pain (LBP).”
• CES is rare among asymptomatic individuals (0.6 cases /100,000 / year).
• CES is more common among those with LBP, affecting 270 per 100,000 (0.27%) per year.

6) “CES has given rise to a substantial number of medicolegal cases within both the chiropractic and physical therapy (PT) professions, perhaps because these clinicians commonly manage LBP.”

• “It is thought that some of these cases occur because clinicians fail to recognize evolving CES features and refer appropriately, leading to a delay in diagnosis and surgery.” [Important]
• “The degree to which the clinician was negligent is unclear as early identification of CES is compounded by potentially mild or gradually-developing symptoms.”
  • “A broad review of medicolegal CES cases found that only 27% of patients initially presented with loss of bowel or bladder function.”

7) “Concerns have been raised regarding documented cases of CES that occurred following chiropractic spinal manipulation (CSM).”

• It has been hypothesized that CSM may worsen pre-existing disc injuries that can lead to CES.
• However, CSM is not likely a meaningful risk factor for CES due to its rarity following CSM when compared to the millions of CSM treatments administered annually.
  • “A retrospective study including 54,846 patients of all ages and with various chief complaints found no instances of CES following 960,140 sessions of CSM.” [Article Review 25-23: A Retrospective Analysis of the Incidence of Severe Adverse Events Among Recipients of Chiropractic Spinal Manipulative Therapy]

8) “Chiropractors are increasingly sought by patients in the US for the treatment of LBP.”

• “Chiropractors are among the most commonly visited healthcare providers for new episodes of LBP, ranking second only to primary care physicians (25.2% of episodes with primary care versus 24.8% with a chiropractor).”
• “Chiropractors use spinal manipulation more frequently than any other type of clinician.”
• “Half of chiropractic patients have LBP, with a subset of these patients having lumbar disc herniation.”

9) “Although CES is a rare event, lumbar disc herniation is its most common cause and is also frequently present among those with LBP.”

10) “Chiropractors may encounter patients who have a heightened risk of developing CES, as these clinicians treat those with LBP and disc disorders.”

11) “Mild adverse events related to CSM, such as transient soreness, are accepted to be common and occur in 23–83% of patients.”

12) The existing literature on CES from CSM “is mostly derived from individual case reports.”

• “In a retrospective study of 7,221 patients presenting to chiropractors for new-onset LBP, no patients met the criteria for CES.”
• “Only a handful of case reports have described chiropractors identifying CES.”

13) “The chiropractic scope of practice is legally regulated, and each US state requires continuing education credits.” [Important]

14) The authors are unaware of any cases of CES following CSM in pediatric patients.

15) While CES typically arises from the lumbosacral region, medicolegal reports have documented CES occurring after thoracic CSM.

16) CES has the potential for a delayed diagnosis.

• The median time to CES diagnosis was 11 days, with a maximum of 90 days.
• In a review of medicolegal cases of CES after CSM, CES was immediate in only one case.
• “These present findings contradict the conclusions of prior studies which suggested that an onset of CES after CSM indicated that CSM was causal.”
  • “However, these prior conclusions were based on case reports, which often highlight atypical situations.”
• “Case reports lack a comparator group or a means to account for confounding variables.”

17) “A self-controlled case series found that patients who underwent emergency surgery for acute lumbar disc herniation had a similar increase in likelihood of visiting either primary care providers or chiropractors prior to the surgery, suggesting that CSM was not a risk factor for lumbar disc herniation.” [Article Review 12-19: Chiropractic Care and Risk for Acute Lumbar Disc Herniation]

18) “Another study found that patients with radicular LBP who underwent CSM were less likely to require disc surgery over the subsequent two years compared to matched controls receiving usual medical care.” [Article Review 10-23: Association Between Chiropractic Spinal Manipulation and Lumbar Discectomy in Adults with Lumbar Disc Herniation and Radiculopathy

• “These consistent findings support the notion that CSM is not a meaningful risk factor for disc herniation or CES.”
• “There are multiple reasons why one may suspect that CSM would not contribute to CES.”
• “Biomechanically, the lumbar facet joints limit axial rotation during manipulation, thereby protecting the lumbar intervertebral discs.” [Key]

19) Findings:

• CES incidence was 0.07% in the CSM cohort compared to 0.11% in the PT cohort.
• “Both cohorts showed a higher rate of CES during the first two weeks of follow-up.”
• “The incidence of CES over three months’ follow-up from the index date of inclusion was lower in the CSM cohort compared to the PT evaluation cohort.”
• “Our findings are consistent with the hypothesis that patients who develop CES after CSM may have evolving symptoms of CES prior to treatment and/or an already-existing disc herniation.” [Important]
• “The present findings show that CES may also arise soon after PT evaluation without manipulation for LBP, suggesting that patients seeking care for LBP are already at a heightened risk of CES and CSM may not be directly causative.”
• “The present study involving over 130,000 propensity-matched patients found that CSM is not a risk factor for CES.” [Key Point]

20) “Patients with LBP have an inherently higher risk of CES compared to asymptomatic individuals.”

• “This reinforces that clinicians should be vigilant to detect and urgently refer patients with CES symptoms for surgical attention.”

21) Conclusions:

• “Findings suggest that CSM is not a risk factor for CES.” [Key Point]
• “Patients with LBP may have an elevated risk of CES independent of treatment.”
• “The present study results support the hypothesis that there is no increased risk of CES following CSM in adults compared to matched controls receiving PT evaluation without spinal manipulation.” [Key Point]
• “The similarity of CES incidence to a prior epidemiologic estimate, and similar incidence between cohorts, suggest that neither CSM nor PT evaluation influenced the incidence of CES.”

22) “These findings pertain to spinal manipulation administered by trained chiropractors rather than other practitioners or laypersons, considering cases of severe adverse events including spinal fracture and CES have been reported following spinal manipulation by untrained individuals.”

23) “These findings underscore the increased CES incidence within the first two weeks after either CSM or PT evaluation, emphasizing the need for clinicians’ vigilance in identifying and emergently referring patients with CES for surgical evaluation.”

24) “Clinicians should be vigilant to identify LBP patients with CES and promptly refer them for surgical evaluation.”

This is the section in our Informed Consent:

Cauda Equina Syndrome: Cauda Equina Syndrome occurs when a low back disc problem puts pressure on the nerves that control bowel, bladder, and sexual function. Representative symptoms include leaky bladder, or leaky bowels, or loss of sensation (numbness) around the pelvic sexual organs (the saddle area), or the inability to start/stop urination or to start/stop a bowel movement. Cauda Equina Syndrome is a medical emergency because the nerves that control these functions can permanently die, and those functions may be lost or compromised forever. The standard approach is to surgically decompress the nerves, and the window to do so may be as short as 12-72 hours, depending. If you have any of these symptoms, tell us immediately, and if we can’t be reached, go to the emergency department immediately.