Chiropractic Manipulation

Chiropractic manipulation refers to a chiropractor applying manipulation to the vertebrae that have abnormal movement patterns or fail to function normally. Chiropractic manipulation (also known as chiropractic adjustment or spinal manipulation), is a common therapeutic treatment for low back pain.¹⁹

The objective of this chiropractic treatment is to reduce the subluxation, which results in an increased range of motion, reduced nerve irritability and improved function.

How a Chiropractic Adjustment Works

Chiropractic manipulation typically involves:

• A high velocity, short lever arm thrust applied to a vertebra
• An accompanying, audible release of gas (joint cavitation) that is caused by the release of oxygen, nitrogen, and carbon dioxide, which releases joint pressure (cavitation)²⁰

• A relieving sensation most of the time, although minor discomfort has been reported (that usually lasts for only a short time duration) if the surrounding muscles are in spasm or the patient tenses up during this chiropractic care.

It should be known that joint cavitation or cracking does not occur at times, typically as a result of significant muscle splinting or the patient not being adequately relaxed during the chiropractic manipulation.

At times like this, it is sometimes best for the chiropractor to apply ice, have the patient rest, or do electrical stimulation and massage prior to attempting the chiropractic adjustment.

Effects of Chiropractic Manipulation

Objective effects of a chiropractic adjustment have been investigated and reported. More specifically, a single chiropractic adjustment produces both sensory and motor effects as well as sympathetic nervous system effects.

The sensory and motor effects of a chiropractic manipulation include:

• Increased joint ROM in all 3 planes and reduction of pain^{21, 22}
• Increased skin pain tolerance level²³
• Increased paraspinal muscle pressure pain tolerance²⁴
• Reduced muscle electrical activity and tension²⁵

Sympathetic nervous system effects of a chiropractic manipulation include:

• Increased blood flow and distal skin temperature (fingertips)²⁶
• Blood pressure reduction^{27, 28}
• Differences in distal skin temperature in the fingertips. Blood flow in the fingertips may rise or fall with specific chiropractic adjustments to the spine. For example, the distal skin temperature has been shown to rise (signifying increased blood flow) following a chiropractic adjustment to C1-C7 and/or L4-L5 while the temperature fell (less blood flow) when the chiropractic adjustment was made to the area between T1-L3.²⁹

Blood chemistry changes after a chiropractic manipulation include:

• Increased secretion of melatonin. Secreted by the pineal gland in the brain, melatonin helps regulate other hormones and maintain circadian rhythm (the 24-hour cycle that determines when people fall asleep and wake up).³⁰
• Increased plasma beta endorphin levels. Endorphins are the body’s natural pain killers; when increased, they help humans manage pain.³¹
• Elevation of Substance P and enhanced neutrophil respiratory burst. Referring to the rapid release of oxygen species, respiratory burst is an important reaction in the degradation of internalized cells and bacteria.³²
• Pupillary diameter changes. Changes in diameter of the pupil (which range from 2-8mm) are often associated with different levels of fatigue and mental workload.³³

Chiropractic Manipulation Techniques

There are many different manipulative techniques that can be utilized in chiropractic, and there is a certain skill level and "art" involved with high velocity, low amplitude adjustment or manipulation. It is perhaps more important for the chiropractor to determine when not to apply the adjustment, which is the reason for the extensive academic load placed on the chiropractic student (4 years of college plus 4 years at a chiropractic college).

The number of chiropractic treatments required for the particular patient varies significantly due to the degree of the injury, the biovariability between patients, and co-morbid risk factors of chronicity (anxiety, depression, poor coping strategies, financial distress, low educational attainment, and others). For example, the chiropractic treatment plan of a grade 1, lumbar sprain/strain rarely demands greater than 4-6 weeks to manage in an uncomplicated case with no co-morbid factors.

References

Complete Listing of References

• Article written By:
• Steven G. Yeomans, DC

October 7, 2009

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