Carpal tunnel syndrome and the "double crush" hypothesis: a review and implications for chiropractic

Upton and McComas claimed that most patients with carpal tunnel syndrome not only have compressive lesions at the wrist, but also show evidence of damage to cervical nerve roots. This "double crush" hypothesis has gained some popularity among chiropractors because it seems to provide a rationale for adjusting the cervical spine in treating carpal tunnel syndrome. Here I examine use of the concept by chiropractors, summarize findings from the literature, and critique several studies aimed at supporting or refuting the hypothesis. Although the hypothesis also has been applied to nerve compressions other than those leading to carpal tunnel syndrome, this discussion mainly examines the original application – "double crush" involving both cervical spinal nerve roots and the carpal tunnel. I consider several categories: experiments to create double crush syndrome in animals, case reports, literature reviews, and alternatives to the original hypothesis. A significant percentage of patients with carpal tunnel syndrome also have neck pain or cervical nerve root compression, but the relationship has not been definitively explained. The original hypothesis remains controversial and is probably not valid, at least for sensory disturbances, in carpal tunnel syndrome. However, even if the original hypothesis is importantly flawed, evaluation of multiple sites still may be valuable. The chiropractic profession should develop theoretical models to relate cervical dysfunction to carpal tunnel syndrome, and might incorporate some alternatives to the original hypothesis. I intend this review as a starting point for practitioners, educators, and students wishing to advance chiropractic concepts in this area

Carpal Tunnel Syndrome: A Review of the Recent Literature

Carpal Tunnel Syndrome (CTS) remains a puzzling and disabling condition present in 3.8% of the general population. CTS is the most well-known and frequent form of median nerve entrapment, and accounts for 90% of all entrapment neuropathies. This review aims to provide an overview of this common condition, with an emphasis on the pathophysiology involved in CTS. The clinical presentation and risk factors associated with CTS are discussed in this paper. Also, the various methods of diagnosis are explored; including nerve conduction studies, ultrasound, and magnetic resonance imaging

Is there Light at the End of the Tunnel? Controversies in the Diagnosis and Management of Carpal Tunnel Syndrome

Carpal tunnel syndrome is a common disorder responsible for considerable patient suffering and cost to health services. Despite extensive research, controversies still exist with regards to best practice in diagnosis, treatment, and service provision. Current best practise would support the use of history, examination and electro-diagnostic studies. The role for ultrasound scanning in diagnosis of carpal tunnel syndrome is yet to be proven. It appears magnetic resonance image scanning has a role where a rare cause for carpal tunnel syndrome may be suspected and also in the detailed reconstruction of the anatomy to aid endoscopic procedures. Treatment options can be surgical or non-surgical and patient choice will dictate the decision. For non-surgical interventions many options have been trialled but until now only steroid use, acupuncture, and splinting have shown discernable benefits. Open surgical decompression of the carpal tunnel appears to be more simple and cost-effective than minimally invasive interventions. For those patients who reject surgery, splinting, acupuncture, and steroid injection can play a role. Recent work looking at different service delivery options has shown some positive results in terms of decreasing patient waiting time for definitive treatment. However, no formal cost-effectiveness analysis has been published and concerns exist about the impact of a stream-lined service on surgical training. In this review, we look at the different diagnostic and treatment options for managing carpal tunnel syndrome. We then consider the different service delivery options and finally the cost-effectiveness evidence

Substitution of phenylephrine for pseudoephedrine as a nasal decongeststant. An illogical way to control methamphetamine abuse

The aim of this review was to investigate the rationale for replacing the nasal decongestant pseudoephedrine (PDE) with phenylephrine (PE) as a means of controlling the illicit production of methamphetamine. A literature search was conducted in electronic databases and use of textbooks. Restrictions have been placed on the sale of PDE in the USA in an attempt to control the illicit production of methamphetamine. This has caused a switch from PDE to PE in many common cold and cough medicines. PE is a poor substitute for PDE as an orally administered decongestant as it is extensively metabolized in the gut and its efficacy as a decongestant is unproven. Both PDE and PE have a good safety record, but the efficacy of PDE as a nasal decongestant is supported by clinical trials. Studies in the USA indicate that restricting the sale of PDE to the public as a medicine has had little impact on the morbidity and number of arrests associated with methamphetamine abuse. Restricting the sale of PDE in order to control the illicit production of methamphetamine will deprive the public of a safe and effective nasal decongestant and force the pharmaceutical industry to replace PDE with PE, which may be an ineffective decongestant. Restrictions on sales of PDE to the public may not reduce the problems associated with methamphetamine abuse

Impact of an Evidence-Based Medicine Curriculum Based on Adult Learning Theory

OBJECTIVE: To develop and implement an evidence-based medicine (EBM) curriculum and determine its effectiveness in improving residents' EBM behaviors and skills. DESIGN: Description of the curriculum and a multifaceted evaluation, including a pretest-posttest controlled trial. SETTING: University-based primary care internal medicine residency program. PARTICIPANTS: Second- and third-year internal medicine residents (N =34). INTERVENTIONS: A 7-week EBM curriculum in which residents work through the steps of evidence-based decisions for their own patients. Based on adult learning theory, the educational strategy included a resident-directed tutorial format, use of real clinical encounters, and specific EBM facilitating techniques for faculty. MEASUREMENTS AND MAIN RESULTS: Behaviors and self-assessed competencies in EBM were measured with questionnaires. Evidence-based medicine skills were assessed with a 17-point test, which required free text responses to questions based on a clinical vignette and a test article. After the intervention, residents participating in the curriculum (case subjects) increased their use of original studies to answer clinical questions, their examination of methods and results sections of articles, and their self-assessed EBM competence in three of five domains of EBM, while the control subjects did not. The case subjects significantly improved their scores on the EBM skills test (8.5 to 11.0, p =.001), while the control subjects did not (8.5 to 7.1, p =.09). The difference in the posttest scores of the two groups was 3.9 points (p =.001, 95% confidence interval 1.9, 5.9). CONCLUSIONS: An EBM curriculum based on adult learning theory improves residents' EBM skills and certain EBM behaviors. The description and multifaceted evaluation can guide medical educators involved in EBM training