Chiropractic and when to order an MRI

If medical practitioners won’t guess, why should the chiropractor regarding when to order an MRI?

Imaging has been one of the cornerstones in chiropractic academics and clinical practice for over a century. Regardless of political rhetoric in the profession regarding when to order an MRI, just look at the Council on Chiropractic Education’s requirements for being conferred a Doctor of Chiropractic. There are hundreds of hours of mandatory training in imaging because imaging is often critical to determining an accurate diagnosis, prognosis and treatment when confronted with pathologies within our scope of practice.

Although palpatory studies, static and motion have had mixed reviews on intra- and inter-rater reliability, we are now starting to see better reliability conclusions on motion palpation, where static palpation persists with poor outcomes.

Imaging and pain generators

Regardless of the finding or outcome, magnetic resonance imaging (MRI) is not about your clinical palpatory findings or immediate biomechanical pathology. It is about the cause of the pain generators.

Your history and clinical findings should be the arbiter of when an MRI should be considered. Before considering when to order an MRI, let’s review the anatomy of typical pain generators managed in chiropractic practice.

1. Spinal Cord: Spinothalamic tract cells innervating the thalamus are the predominant pain generators.
2. Nerve Roots: These include those that exit the spinal cord through the neural canal and the foramina and those in the cauda equina.
3. Facets Joints: You have nociceptors that are in the facets and innervate the lateral horns.
4. Joint Capsule: Pacinian corpuscles (crimp receptors), Ruffini corpuscles (stretch receptors), golgi tendon/ligament organs, and nociceptors. They all innervate the lateral horn and comprise your spinal mechanoreceptors.

Although the list is long, let’s examine the typical causes of those pain generators being triggered in chiropractic practice:

1. Patho-Neuro-Biomechanical Pathology (Vertebral Subluxation Complex): This typically causes immediate localized pain, triggers nociceptors in the facets, and innervates the lateral horn leading to central sensitization and pain in disparate spinal regions
2. Herniated Disc: Focal displacement of disc material beyond the limits of the intervertebral discspace:
   1. Protrusion-type Herniation: if the greatest distance between the edges of the disc material presenting outside the disc space is less than the distance between the edges of the base of that disc material extending outside the disc space. The base is wider than the apex.
   2. Extrusion (migrated or comminuted)-type Herniation: is present when, in at least one plane, any one distance between the edges of the disc material beyond the disc space is greater than the distance between the edges of the base of the disc material beyond the disc space.
   3. Extrusion (segmented or fragmented)-type Herniation: when no continuity exists between the disc material beyond the disc space and that within the disc space.
   4. Diffuse Bulged Disc (degeneration): no disc material extends beyond the periphery of the disc space, which must extend beyond 180 degrees.

Myelopathy

Another consideration of imaging as management of spinal issues is myelopathy. Myelopathy is defined as a compression of the spinal cord with ensuing neurological deficit distal to the level of the lesion. The management of a myelopathic clinical diagnosis is consistent in medicine and chiropractic. An immediate MRI with no contrast (with no prior surgical history) is indicated, and an immediate referral to a neurosurgeon is typically the first line of treatment.

Short of a myelopathic finding, a typical presentation will be either localized pain or radiating pain, with and without motor loss. For localized pain, medicine and chiropractic agree, no advanced imaging is warranted. If the pain persists for more than 45 days with no change in clinical presentations, while being treated conservatively (inclusive of chiropractic care) an MRI is then reasonable to ascertain why and conclude an accurate cause of the lingering pain.

MRIs: chiropractic vs. medicine

Here is where there is a dichotomy of management paths between chiropractic and medicine and an experienced/trained practitioner should not conflate the care paths between the two.

Medicine, as reflected in the American College of Radiology Appropriateness Criteria, does not consider MRI as an initial diagnostic modality with or without contrast with acute low-back pain with or without radiculopathy in the absence of red flags. Considering that medicine is proficient in diagnosing anatomical pathology (fracture, tumor, infection, herniation) I would agree this is reasonable in an office where management with a pharmacological solution or physical therapy is the primary focus of treatment as with medical primary care providers.

However, most diagnoses in medical offices for spinal-related pain are non-specific where the evidence in the literature concluded that chiropractic outcomes are 313% superior to physical therapy and 20% superior to medicine regarding disability.

In medicine, spinal practitioners also understand the necessity for immediate MRIs. Neurosurgeons and orthopedic spine surgeons will 100% of the time order an MRI if there are radiculopathic findings and appreciable associated motor loss. The reason, without seeing, you are guessing, and these highly trained sub-specialists do not guess. Why should the chiropractic profession?

Chiropractic has two issues that must be considered; the first is delivering a high velocity-low amplitude chiropractic spinal adjustment with a patient who has presented with significant radiculopathic findings or appreciable motor loss. The question that must be concluded before treatment is that of an accurate diagnosis. What is causing the radiculopathic finding? Are you delivering a high-velocity thrust into a region where there is no room between the space-occupying lesion and neural elements?

Remember, the disc is a very strong sac of gelatinous and viscous fluid that will expand upon an increase of thecal pressure. A chiropractic spinal adjustment increases intrathecal pressure. Does that give concern for chiropractic care? No, if you have an accurate diagnosis with enough cerebral spinal fluid space on any side of the cord or root. In the absence of space around the neural element, you either have an abutment or a compression of the spinal cord or nerve root.

When to order an MRI is clinically warranted

Choosing to manage the case conservatively with a chiropractic spinal adjustment, decompression, bed rest or a referral to a neurosurgeon or orthopedic spine surgeon is a clinical decision we all have to make. However, the decision when to order an MRI cannot be done blindly, and an immediate MRI is clinically warranted with the above clinical constructs.

These are care paths currently taught in chiropractic academia at the doctoral level and in medical academia at the post-doctoral level.

MARK STUDIN, DC, is an adjunct associate professor of chiropractic at the University of Bridgeport, College of Chiropractic; adjunct professor at Cleveland University – Kansas City, College of Chiropractic; and adjunct professor of Clinical Sciences at Texas Chiropractic College. He is the president of the Academy of Chiropractic, teaching doctors of chiropractic and interfacing with the medical and legal communities (DoctorsPIprogram.com). He can be reached at DrMark@AcademyOfChiropractic.com or at 631-786-4253.