We appreciate Dr. Kohlhardt’s letter. Our article focused on the prevalence of and possible risk factors associated with CTS among dentists tested at the annual ADA Health Screening Program.
As a result of this testing venue, time limitations restricted our ability to include other diagnostic regimens. Furthermore, the article was not meant to be a review of diagnostic testing related to establishing the diagnosis of CTS, which, as Dr. Kohlhardt noted, is a complex issue.
Dr. Kohlhardt does bring up several important points. The main issue is related to the "double crush" theory that an injury to the nerve at the root level may make the nerve more susceptible to injury distally. This was first suggested by Upton and McComas1 in 1973 but is still a controversial hypothesis.
A recent study by Richardson and colleagues2 looked at the relationship between the occurrence of CTS and cervical radiculopathy and did not find evidence to support this hypothesis. Our clinical experience is in agreement with Richardson and colleagues’ findings. CTS and cervical radiculopathy can occur in the same individual, but we do not feel that the presence of neck and shoulder symptoms (and specifically cervical radiculopathy) places the individual at greater risk for an entrapment at the wrist.
We did find that dentists had a variety of symptoms in the upper arm, shoulder and neck. These complaints are most likely muscular in origin and not related to a pinched nerve in the neck. The musculoskeletal problems in the neck, shoulder and upper arm are not related to the development of CTS, and the few dentists who have a true cervical radiculopathy are probably at no greater risk for CTS.
Standard electrodiagnostic evaluation for CTS usually does include evaluation of the muscles in the upper arm and neck to exclude the possibility of a cervical radiculopathy or other proximal nerve entrapment.
Again, due to time constraints, we did not perform the needle portion of the electromyography in our screening of dentists. However, we do not feel that it would significantly add to our understanding of CTS among these screened dentists.
Hopefully, the increased focus on occupational ergonomic issues and continued screening opportunities will raise awareness of symptoms and risk factors, as well as improve the opportunity for prevention and success of early intervention. Regardless of the diagnosis given, 28 percent of screened dentists reported symptoms of hand pain and numbness.
We agree with Dr. Kohlhardt that additional research would bring a better understanding of the source of this pain, as well as remediation strategies that would most benefit dental professionals.
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