Once a patient has been convinced that his or her spine harbors vertebral subluxations that can cause disease or affect general health, any one of dozens of chiropractic adjustive techniques might be used to correct and prevent recurrence of such subluxations. One of the most bizarre methods of adjusting the spine uses a handheld instrument with a spring-loaded or electrically powered mallet or stylus to tap on selected vertebrae. A dubious leg-length check might be used to determine if correct alignment has been restored, a procedure so implausible that it is the subject of many of the letters I have received from chiropractic patients.
Some computerized adjusting instruments use a piezoelectric sensor that will allegedly locate and correct a vertebral subluxation by analyzing the echo of an oscillating force applied to a vertebra. Such an instrument has proved to be an effective way to sell chiropractic care and is often advertised as “advanced chiropractic technology.” While some chiropractors genuinely believe that the vertebral subluxation theory is valid, subluxation-based “chiropractic technologies” have more to do with marketing than with health care.