Primary Care Corner with Geoffrey Modest MD: Carpal Tunnel Mega-Guidelines

By Dr. Geoffrey Modest

The Am Academy of Orthopedic Surgeons just released their evidence-based guidelines on the management of carpal tunnel syndrome (see www.aaos.org/guidelines). These are the most extensive guidelines I have seen (982 pages!!), with remarkably extensive documentation (reviewing and critiquing probably every article on carpal tunnel syndrome since the advent of papyrus), though the conclusions do not really affect much of what is current practice.

Details:

• Thenar atrophy is strongly associated with carpal tunnel syndrome (CTS), though lack of atrophy does not rule-out CTS (strong evidence) [my guess is that we in primary care see earlier cases of CTS than orthopods do, and in my experience it is somewhat unusual to see thenar atrophy at the time of diagnosis]
• Don’t use Phalen test, Tinel sign, or flick sign [the flick sign is when the patient flicks their wrist (snapping the hand in a rotational motion in response to the question of what the patient does to relieve the pain/numbness)]  (strong evidence)
• Other not useful tests include reverse Phalen test, 2-point discrimination, carpal compression test (moderate evidence)
• Not useful to use any of the following alone in ruing-in or out CTS: sex, ethnicity, bilateral symptoms, diabetes, worsening symptoms at night, patient localization of symptoms, age, BMI (moderate evidence) [my experience is that patients will often feel that their finger numbness/pain involves all 5 fingers, which I think is just that it is really easy to assume/generalize that all of the fingers are involved], though there is moderate evidence that diagnostic questionnaires are helpful in the diagnosis
• Hand-held nerve conduction studies might be useful (limited evidence)
• MRI: do not use routinely (moderate evidence)
• Ultrasound: do not use routinely (limited evidence)
• Risk factors for CTS include (moderate to strong evidence): BMI, high hand/wrist repetition rate, peri-menopause, rheumatoid arthritis, psychosocial factors (?/ not defined), distal upper extremity tendinopathies and tendinitis, assembly line work, computer work, vibration, dialysis, fibromyalgia, distal radius fracture
• Risk factors not associated with CTS: oral contraceptives, female hormone replacement therapy (moderate evidence)
• Risk factors with conflicting results: diabetes, smoking, age, sex
• Treatments:
  • Ones that work:
    • Immobilization (strong evidence)
    • Steroid injection(strong evidence)
    • Oral steroids(moderate evidence)
    • Ketoprofen phonophoresis gel (moderate evidence)
    • Therapeutic ultrasound and laser therapy work (but limited evidence)
    • Surgery works and tends to be longer lasting (at 6-12 months) than splinting, NSAIDs, or a single steroid injection
  • And, ones that don’t work:
    • ​NSAIDs, diuretics, gabapentin, pyridoxine (moderate evidence).
    • Magnet therapy (strong evidence)

So, a few observations:

• This huge compendium, I assume, reflects the state of the art for CTS, in terms of actual studies done
• But, there are several issues not in these guidelines (probably reflecting lack of studies) which seem to me to be important:
  • In terms of presentation, I have seen several patients with pain from CTS which radiates proximally to the elbow region and one patient where it went almost to the shoulder. This is certainly reported in the literature. And these patients responded to CTS injections (though I would be more inclined to get nerve conduction studies — NCS — in these cases, see below, to differentiate from C6-7 nerve impingement and cervical radiculopathy)
  • They do not include pregnancy or hypothyroidism in the list of causes/associations of CTS
  • They do not mention other factors that can lead to compression in the carpal tunnel, albeit uncommon, such as acromegaly or any infiltrative disorders (I have seen/heard of cases of sarcoidosis, leukemia, TB, or hemotomas causing CTS)
  • ​One pretty common presentation, I have found, is that when I ask patients to describe their symptoms, they spontaneously do the “flick sign” (sort of like the Levine’s sign of a clenched fist over the chest as a sign of anginal pain). Not everyone does that, but when they do, I have found very high specificity (this sign is dismissed in the guidelines, but on reviewing the individual studies, some showed high specificity, though the majority did not. So my experience is no doubt anecdotal, but pretty consistent)
  • Although the sensitivity and specificity of the individual signs for CTS (Phelan’s, Tinel’s) are middle-ground (in the 70% range), perhaps also anecdotally, a combination of them being present improves diagnosis
  • ​So what is the role of nerve conduction studies (not addressed in the guidelines)?? Does everyone need them? Although they may be reasonable in most cases prior to doing surgery (though some surgeons do not require them), are they necessary prior to other interventions? [When I get a consistent history, physical and perhaps some positive hand maneuvers, I feel pretty certain about the diagnosis and do go directly to injections if conservative measures are insufficient (e.g. using braces). And in cases where I feel that there is a reasonably strong possibility the symptoms reflect CTS, I have used injections as both a diagnostic and therapeutic trial]. And, in terms of NCS, mild CTS may not have any abnormalities in nerve conduction (i.e., not sure what the gold standard for CTS is. The studies cited in the guidelines most often used NCS, though some relied on neurologists, etc. And the guidelines do not even discuss what they consider to be the gold standard)
  • My experience with CTS injections (I’m sure I’ve done a couple of dozen over the years) has been that they are almost always successful (and the vast majority have been without NCS confirmation). These are really pretty easy injections, and I have used the combo of an intra-articular steroid (e.g. triamcinolone) with 1% lidocaine (1 cc of each). And, in most cases these are done only once or twice, with very long-lasting effects (i.e., I do not hear a further complaint, even years later). If the symptoms recur after 2 injections, I suggest a referral for the more definitive surgery for carpal tunnel release.