How do chiropractors know where to adjust?
In this blog, we’ll examine (pun intended) the characteristics of a person who is likely to respond well to an adjustment.
Then, we’ll look at the techniques chiropractors typically use to determine the best place to deliver an adjustment.
Not every patient responds the same to chiropractic adjustments or high velocity, low-amplitude (HVLA) spinal manipulation (SMT). That is obvious.
However, some evidence-based patient characteristics can predict who will respond better than others.
Utilizing the research evidence on responsiveness characteristics to SMT can help us make better prognoses to our care.
Spinal Segmental Stiffness
Researchers have found that patients with at least one hypomobile vertebral segment or spinal segmental stiffness beyond normal respond better to HVLA thrust manipulation.
Further, the thrust SMT improved pre-SMT spinal segmental stiffness, while non-thrust manipulation did not.
Interestingly, this included both global stiffness (stiffness of the underlying tissues throughout the measurement) and terminal stiffness (stiffness at the measurement endpoint).
Decreased activation and recruitment of the multifidi muscles is a common feature in spinal segmental dysfunction.
Those patients with increased multifidus thickness and activation sustained over a one-week follow-up period after SMT are good responders.
SMT activates the multifidus muscle with lasting effects in good responders.
The multifidus is distinctive for the unusually high number of muscle spindles it contains.
Muscle spindles are sensory receptors in muscles that detect changes in the muscle’s length and report this information back to the central nervous system.
The central nervous system uses the information to calculate the body’s current position.
Atrophy of the multifidus muscle was found in patients with back pain and lumbar radiculopathy; lumbar degenerative kyphosis increased fat infiltration to the multifidus muscle in those patients with lumbar radiculopathy or lumbar degenerative kyphosis.
Minimal Facet Joint Degeneration
In lumbar spine back pain patients, SMT responders tended to have a lower prevalence of severely degenerated facets than non-responders, according to a 2019 study.
MR imaging studies also found that SMT responders were also characterized by significant increases in post-SMT apparent diffusion coefficient (ADC) values at discs associated with painful segments identified by palpation.
Curiously, there was no significant difference in other spinal degenerative features found on MR imaging, such as Modic changes.
More Localized Symptoms
Patients with lumbar pain and no symptoms extending distal to the knee are better responders to SMT.
Find Signals in All the Noise
Shorter Duration of Symptoms
Spinal pain symptom duration of fewer than 30 days for cervical and 16 days for lumbar spine pain conditions have a better immediate response to SMT.
Early Symptomatic Response to SMT
Acute neck pain patients (<4 weeks symptoms) that reported improvement in 1 week have shown a 3X greater improvement at three months than those unimproved at one week.
For patients with chronic pain (>12 weeks symptoms), those reporting improvements in 1 month had a 6X greater improvement at three months compared to unimproved at one week.
Acute low back pain patients respond better than chronic low back pain patients.
Low back pain patients respond better if at least one hip has more than 35 degrees of internal rotation.
Predictors of improvement in Thoracic spine pain were a more significant decrease in both pain intensity and tenderness.
Poor Responder Characteristics
Patients who respond poorly to SMT most often have one or more factors as the reason:
- Inappropriate technique
- Poorly executed technique
- The unsuitable patient selected
- The condition was not appropriate for the technique or treatment
How Do Chiropractors Know Where to Adjust?
Since the beginning of our education, chiropractors have been taught many methods to locate where to adjust.
Sometimes it seems that if you get ten chiropractors together, you get ten different ways of finding where to apply an adjustment.
The methods often contradict each other.
Several researchers have looked at the research evidence for various chiropractic analysis methods and have rated their reliability.
Those that showed good evidence of reliability were designated as favorable, and those that did not have adequate evidence were rated as unfavorable.
The following methods were found favorable:
- Pain provocation
- Posture: antalgia, kyphosis, lordosis, scoliosis
- Stiffness as determined by instrument
- Static palpation for major anatomical landmarks
- Motion palpation with pain
- Manual muscle testing for strength
- Range of motion
- Skin rolling surface EMG for flexion-relaxation phenomenon in the lumbar region
- Motion palpation to localize the site of care
- Stiffness by joint springing or overpressure testing
The following methods were found unfavorable:
- Manual muscle testing for non-pathologic altered function
- Para-spinal skin temperature to locate the site of care
- Surface EMG for the site of care
- Radiographic imaging for localizing the site of care
For daily visits, most chiropractors use some functional examination protocols.
These include postural analysis, segmental alignment or position, range of motion, reactive muscle testing, kinetic palpation, and provocative testing.
The chart below shows a summary of each, along with their strengths and weaknesses.
Functional Joint Examination Methods
(Order of Least to Most Invasive)
Positional and Postural
Rationale: Misalignment creates joint and connective tissue stress.
- Assesses muscle imbalance and tightness
- Positional dyskinesia demonstrated
- Difficult to assess anomalies
- Alignment doesn’t correlate with kinetic disturbance
- Doesn’t identify unstable joints
Rationale: Altered instantaneous axis of rotation.
- Easy to implement
- Quick screen
- Demonstrative to patient
- Assesses quantity but not quality of motion
- Global, not-specific
Reactive Muscle Testing
(Active MMT, Passive Reflex Testing)
Rationale: Mechanoreceptor dysfunction.
- Neurological indicator of joint stress
- Indicates neurological dysfunction
- Very demonstrative to patient
- Secondary indicator
- Validity and reliability
- Can’t gauge prognosis
- Highly skill dependent with questionable accuracy and reliability
(Joint Play Testing)
Rationale: Connective, muscular, and articular tissue restrictions prevent normal arthokinematics.
- Primary indicator
- Can assess quality of motion
- Can differentiate between acute and chronic conditions
- Can identify unstable joints
- Can monitor progress
- Can offer prognosis information
- Labor intensive
- Highly skill dependent requiring extensive practice
- Modest to good intra-examiner reliability; fair to moderate inter-examiner reliability
- Best used in combination with other exam methods rather than as a stand-alone
Rationale: Pain on testing indicates articular tissue irritation or inflammation.
- Most literature evidence support
- Demonstrative to patient
- Can be integrated with orthopedic exam (overpressure) and joint play end feel analysis
- Narrow scope of assessment (pain only)
The practice of locating where to adjust currently remains as much or more art than science.
Deliberate practice in any chosen method is necessary to become proficient. With more research, we can get even better.