Understanding Cauda Equina Syndrome

Safety, Concerns, Chiropractic Care

 A primary care provider (PCP) is a health care provider who provides the first contact for a person with a new health concern. Historically, the primary care provider is a medical doctor (MD), an osteopathic doctor (DO), a physician assistant, certified (PA-C), or an advanced registered nurse practitioner (ARNP). The provider has the education and experience to propose a likely diagnosis for the new health concern. This education and experience are commonly based upon good knowledge as well on symptoms, history, examination findings, laboratory results, imaging, electrodiagnostic testing, etc.

Once the working diagnosis is proposed, the primary care provider also has the education and experience to initiate appropriate treatment or to refer the patient to a specialist if such a referral is in the patient’s best interest.

Despite the highest standards, intelligence, logic, education, and training, diagnostic errors are commonplace. A study published earlier this year (2024) in the BMJ [British Medical Journal] Quality & Safety was titled (1):

Burden of Serious Harms from Diagnostic Error in the USA

This study was the first national estimate of permanent morbidity and mortality resulting from diagnostic errors across all clinical settings, including both hospital-based and clinic-based care each year in the USA. The goal of this research was to estimate the total number of serious misdiagnosis-related harms (i.e., permanent disability or death) occurring annually in the USA across all care settings (ambulatory clinic, emergency department, and inpatient). The authors are from Johns Hopkins School of Medicine and Harvard Medical School. The authors note:

“An estimated 795,000 Americans become permanently disabled or die annually across care settings because dangerous diseases are misdiagnosed.”

“This manuscript provides the first robust, national annual US estimate for serious misdiagnosis-related harms (nearly 800,000 combined deaths (~371,000) or permanent disabilities (~424,000)) across care settings (ambulatory clinic, emergency department, and inpatient).”

“Across clinical settings (ambulatory clinics, emergency department, and inpatient), we estimate that nearly 800,000 Americans die or are permanently disabled by diagnostic error each year, making it the single largest source of serious harms from medical mistakes.”

 “Total annual diagnostic errors in the USA likely number in the tens of millions.”

Primary care providers are aware of these concerns, and as such they constantly monitor, reassess, and follow the response to initial treatment in their patients. The complexity of human genetics, epigenetics, and physiology, and the immense range of potential illnesses, are overwhelming.

Doctors of chiropractic (DC) are not considered to be primary care providers. Rather, chiropractors are portal of entry providers (POE).

A POE provider is any healthcare provider to whom a patient has direct access, and a referral is not necessary. This means a person can directly call, consult, and receive care from a chiropractor without a referral.

Other portal of entry providers includes dentists, podiatrists, and optometrists.

Primary care providers are educated and trained to provide comprehensive diagnosis and treatment of medical diseases. In contrast, chiropractors are not meant to provide treatment for medical diseases. Chiropractors are primarily trained and educated on the diagnosis and treatment of neuromusculoskeletal problems and to address them primarily from a mechanical perspective (the chiropractic spinal adjustment). Yet, chiropractors are educated and trained to be able to assess if a patient’s condition is a neuromusculoskeletal problem or if there might be some other explanation. As such, chiropractors work closely with their patient’s primary care provider and other involved specialists.

Chiropractors are licensed portal of entry providers in all 50 U.S. states. All U.S. chiropractors are graduates of fully accredited chiropractic colleges (2). Chiropractic care is reimbursed by Medicare, Medicaid (Medical), Worker’s Compensation insurance, automobile collision insurance, and most private health insurers.

Although all of chiropractic education is accredited nationally (indirectly through the U.S. Department of Education, via the Council on Chiropractic Education (2)), the licensing for chiropractors is done by the individual states. All states establish oversight boards for professionals to help protect its citizens. Examples include medical boards, insurance boards, contractors boards, etc. Similarly, all states have an oversight licensing board for the chiropractic profession. Although the name of the board will vary somewhat state to state, generally it is known as the “Board of Chiropractic Examiners.”

Each state’s licensing board will create a set of rules and regulations for its licensed chiropractors. These rules and regulations will vary somewhat state to state, but as a central theme most of them are fairly similar. A common topic is the details of using Informed Consent.

Informed Consent

Every type of health care is associated with some risks of potential problems. This includes chiropractic health care. Informing patients about potential problems associated with chiropractic health care is known as Informed Consent.

Typically, Informed Consent would include a description of the type of treatment, as follows:

Chiropractic adjustments are the moving of bones with the doctor’s hands or with the use of a mechanical device or machine (drop table). Frequently, adjustments create a “pop” or “click” sound/sensation in the area being treated.

The risks of potential problems associated with chiropractic health care are classically those associated with mechanical-based care. These might include:

• Neck Artery Dissection
• Stroke secondary to neck artery dissection
• Disc Injuries
• Nerve Injury; this would include spinal cord, nerve root, and/or the peripheral nerve
• Soft tissue injury to ligament, tendon, muscle, or fascia
• Soreness
• Fracture

More details about each of these would be explained to the patient by their chiropractor. Other risks unique to the chiropractor’s procedures or equipment would also be included. All discussions are often done both in writing and orally. As with all other health care providers, the patient is asked to sign and date their understanding of these issues.

Chiropractic meetings and lectures often advise about another potential problem that might be related to mechanically based treatment (adjustments): Cauda Equina Syndrome. An Informed Consent discussion pertaining to Cauda Equina Syndrome might include something like this:

Cauda Equina Syndrome occurs when a low back disc problem puts pressure on the nerves that control bowel, bladder, and/or sexual function.

Representative symptoms of Cauda Equina Syndrome 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 medical approach for Cauda Equina Syndrome 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 before seeing us, during an appointment with us, or after an appointment with us, tell us immediately, and if we can’t be reached, go to the emergency department immediately.

The spinal cord terminates at the upper part of the low back, say at about the level of the first lumbar vertebrae (L1). The long nerve roots that leave the upper part of the low back to exit from the lowest portion of the low back create an appearance of a horse’s tail, hence the terminology cauda equine. Cauda Equina Syndrome occurs when a central or midline disc herniation puts pressure on the central part of the cauda equina.

Chiropractic’s Impressive Safety Record

People become healthcare providers because they want to help others with their health. Most healthcare providers are horrified at the thought that anything they did or failed to do could end up harming a patient. Yet, medical care is complex and often invasive. Medical care routinely uses drugs and surgery. As such, for decades, top universities and top medical journals have been documenting medical errors (1, 3, 4, 5, 6, 7, 8, 9, 10).

In contrast, chiropractors do not use drugs or surgery. Chiropractic care is mechanically based care. At its core is the chiropractic adjustment (specific line-of-drive manipulation). It is also quite common for chiropractors to employ adjunct mechanical interventions, such as tissue work and/or exercise.

Chiropractic’s record of safety and low risk of injury is very impressive. Two recent (2022, 2023) very large studies have confirmed the incredible safety of spinal manipulation and chiropractic spinal adjusting (11, 12). These studies are reviewed here:

In 2022, a study was published in the journal Healthcare, titled (11):

Safety of Chuna Manipulation Therapy
in 289,953 Patients with Musculoskeletal Disorders

This study was from medical facilities in South Korea. It involved a form of high-velocity low amplitude spinal adjustment (specific line-of-drive manipulation). This type of traditional joint manipulation is similar to that in chiropractic. This type of manual therapy has been incorporated into the Korean health care system and is administered in 16.4% of inpatients and 83.6% of outpatients with musculoskeletal disorders in Korean medicine hospitals specializing in spine and joint diseases. The authors note:

“Manual therapy is performed in various forms by chiropractors, osteopaths, and physical therapists across the world, including the United States, Europe, and Australia.”

“The use of spinal manipulation has increased in recent decades in Western countries, as has the popularity of chiropractic therapy among American adults.”

“The UK National Institute for Health and Clinical Excellence guidelines now recommend manual therapy for treating persistent or subacute lower back pain.”

This study was very robust. The authors assessed 2,682,258 manipulation procedures that were performed on 289,953 patients from 14 different facilities. The authors state:

“In this study, 289,953 patients and more than 2.5 million cases of [manipulations] were reviewed, making it a rare, very wide-ranging, and reliable investigation of severe adverse events.”

“Our analysis of 289,953 patients and 2,682,258 cases of [manipulation] indicates that both mild–moderate and severe adverse events are rare after [manipulation].”

“Adverse events of any level of severity were very rare after [manipulation].”

“There were no instances of carotid artery dissection or spinal cord injury.”

In this study, no life-threatening or fatal events were identified. There were no cases of artery dissection or cauda equina syndrome. Eleven rib fractures were identified, and all were on elderly patients with known osteoporosis. All rib fractures healed and all patients recovered without residuals. There were no permanent injuries found in any of the study subjects.

••••

In 2023, a study was published in the journal Scientific Reports, titled (12):

A Retrospective Analysis of the Incidence of Severe Adverse Events
Among Recipients of Chiropractic Spinal Manipulative Therapy

This study examined the incidence and severity of adverse events (AEs) in 54,846 patients who received 960,140 chiropractic spinal manipulations. The data originated from 30 chiropractic clinics using 38 different chiropractors. All patients received spinal manipulative therapy (SMT) administered via manual thrust (i.e., a hands-on impulse applied to the spinal joints). The authors concluded:

“In this study, severe spinal manipulative therapy-related adverse events were reassuringly very rare.”

“There were no adverse events related to stroke or cauda equina syndrome.” 

“There were no cases of stroke, transient ischemic attack, vertebral or carotid artery dissection, cauda equina syndrome, or spinal fracture.”

“No adverse events were identified that were life-threatening or resulted in death.”

“No adverse events were reported to be permanent.”

Likewise, in this study, there were no life-threatening or fatal events. There were no cases of artery dissection, stroke, or cauda equina syndrome.

There were two rib fractures, both occurring in elderly patients with a history of osteoporosis. Both patients recovered without residuals. There were no permanent injuries found in any of the study subjects.

It is noteworthy that in this study the authors specifically commented on the incidence of cauda equina syndrome; there were none.

••••

Earlier this year (2024), an article was published in the journal PLOS (Pubic Library of Science) ONE; titled (13):

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

The authors note that the relationship, if any, between spinal manipulation and cauda equina syndrome, has been poorly explored in the literature. The existing literature on CES from spinal manipulation “is mostly derived from individual case reports.” They specifically state:

“...there was no adequately powered and designed study to examine this potential association.”

Therefore, to clarify any potential relationship, the authors conducted this robust study. They used a cohort of 134,440 low back pain (LBP) patients with a mean age of 51 years:

• Half of the patients (n = 67,220) were treated chiropractically with spinal manipulation.
• Half of the patients (n = 67,220) were treated with physical therapy and received no spinal manipulation.

“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 authors do not believe that spinal manipulation is a meaningful risk factor for CES due to its rarity following manipulation when compared to the millions of manipulation treatments administered annually.

The authors remind the reader that the cauda equina is a bundle of nerve roots arising from the spinal cord at the upper lumbar spine. Compression of these nerve roots, typically by a midline/central disc herniation, can cause cauda equina syndrome (CES), which includes combinations of:

• Low back pain and/or lower extremity symptoms
• Bladder/bowel dysfunction
• Reduced saddle area sensation
• Sexual dysfunction

The authors also note:

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

The authors note that 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 are increasingly sought by patients in the US for the treatment of LBP. Approximately half of chiropractic patients have low back pain.

Lumbar disc herniation is a frequent cause of low back pain and it is the most frequent cause of CES. Chiropractors use spinal manipulation more frequently than any other type of clinician.

Findings from this study include:

“The incidence of CES over three months’ follow-up from the index date of inclusion was lower in the [manipulation] cohort compared to the [physical therapy] evaluation cohort.”

The authors made these conclusions:

“Our findings are consistent with the hypothesis that patients who develop CES after [manipulation] may have evolving symptoms of CES prior to treatment and/or an already-existing disc herniation.”

“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 [manipulation] may not be directly causative.”

“The present study involving over 130,000 propensity-matched patients found that [manipulation] is not a risk factor for CES.”

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

“Findings suggest that [manipulation] is not a risk factor for CES.”

“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 [manipulation] in adults compared to matched controls receiving PT evaluation without spinal manipulation.”

••••

Summary

The work presented here indicates that chiropractic spinal

manipulation is not causative of cauda equina syndrome. The largest assessments of adverse events following spinal manipulation (344,799 patients receiving 3,642,398 manipulations) found no incidence of cauda equina syndrome. In the management of patients with low back pain, the incidence of cauda equina syndrome is lower in those being managed by chiropractors who manipulate as compared to those being managed by physical therapy without spinal manipulation.

Although spinal manipulation is not causing cauda equina syndrome, several points should be emphasized:

• Chiropractors treat low back pain
• Low back disc herniations cause low back pain
• Low back disc herniations cause cauda equina syndrome
• Chiropractors are portal of entry providers

With every low back pain patient, a suspicion of a developing cauda equina syndrome should be ever present. Chiropractors should question patients regularly about bowel, bladder, sexual, and saddle problems. Chiropractors should educate their patients as to the signs and symptoms of a developing cauda equina syndrome. Failure to timely identify patients with a developing cauda equina syndrome and to make an appropriate referral for advanced imaging and/or a surgical consultation can have serious, and potentially life-long, adverse consequences.

This last study (13) makes these ending comments:

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

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

REFERENCES:

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10. Makary MA; Medical Error: The Third Leading Cause of Death in the United States; British Medical Journal (BMJ); May 3, 2016; Vol. 353; Article i2139.
11. Kim S, Kim G, Kim H, Park J, Lee J, and nine more; Safety of Chuna Manipulation Therapy in 289,953 Patients with Musculoskeletal Disorders: A Retrospective Study; Healthcare; February 2, 2022; Vol. 10; No. 2; Article 294.
12. Chu E, Trager RJ, Lee L, Niazi IK; A Retrospective Analysis of the Incidence of Severe Adverse Events Among Recipients of Chiropractic Spinal Manipulative Therapy; Scientific Reports; January 23, 2023; Vol. 13; No. 1; Article 1254.
13. Trager RJ, Baumann AN, Perez JA, Dusek JA, Perfecto RT, Goertz CM; 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

“Authored by Dan Murphy, D.C.. Published by ChiroTrust^® – This publication is not meant to offer treatment advice or protocols. Cited material is not necessarily the opinion of the author or publisher.”