Carpal tunnel syndromeBMJ 2014; 349 doi: https://doi.org/10.1136/bmj.g6437 (Published 06 November 2014) Cite this as: BMJ 2014;349:g6437
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We agree with Middleton and Anakwe that carpal tunnel syndrome (CTS) is usually idiopathic in aetiology . There are several other causes and associations including pregnancy, trauma, obesity, hypothyroidism, renal failure, diabetes and inflammatory arthritis. Treatment of the underlying condition particularly in the case of inflammatory arthritis is the most appropriate course of action. We wish to note the importance of CTS as an occupational disease. It can be specifically related to the use of vibrating power tools, frequently used in factory based assembly work, building, forestry and mining industries. This is separate entity from hand-arm vibration syndrome (HAVS). Rapid repetitive flexion and extension of the wrist (which increases pressure in the Carpal Tunnel) in the workplace has also been associated with CTS. The Industrial Injuries Advisory Council has concluded that vibration and repetitive flexion and extension can cause CTS and is an occupational cause for CTS and recommended it as a prescribable disease .
The evidence that vibratory tools can be a causative mechanism in the development of CTS has been available for some 17 years  and a further review discussed identification and prevention . A systematic review by Palmer et al commissioned by the UK Industrial Injuries Advisory Council found reasonable evidence that both the use of hand held vibratory tools and occupations requiring prolonged repetitious flexion and extension at the wrist increased the risk of CTS around two fold . This was further supported by a meta-analysis published in 2012 which included 37 studies. Using the US National Institute for Occupational Heath and Safety Criteria, a significant association between CTS and use of vibratory tools was found (12 studies, OR 2.73, 95% CI 1.90, 3.92; P<0.001) , between CTS and repetitive movements of the wrist (25 studies, OR 2.30, 95% CI 1.75, 3.01) and between CTS and hand force (13 studies, OR 2.18, 95% CI 1.47, 3.25) .
It is therefore important to take an occupational history in a patient with carpal tunnel syndrome and consider workplace interventions to reduce the risk to employees and aid recovery.
Similarly, it is important to remember that treating the underlying cause of carpal tunnel syndrome (for example by treating inflammatory arthritis, improving glycaemic control in a diabetic, encouraging weight loss or providing thyroid hormone replacement) may lead to a resolution of the problem and avoid invasive treatments such as injections or surgery.
Elizabeth Curtis MRCP Specialist Registrar
Richard Hull FRCP Consultant Rheumatologist
Queen Alexandra Hospital, Portsmouth UK
1. Middleton SD, Anakwe RE: Carpal Tunnel Syndrome. BMJ; 349:g6437,(2014). (8th November)
2. Industrial Injuries Advisory Council: Work Related Upper Limb Disorders. Department for Work and Pensions, (2006).
3. Tanaka S, Wild DK, Cameron LL, Freund E: Association of occupational and non-occupational risk factors with the prevalence of self-reported carpal tunnel syndrome in a national survey of the working population. Am J Ind Med 32(5), 550-556 (1997).
4. Macfarlane GJ: Identification and prevention of work-related carpal-tunnel syndrome. Lancet 357(9263), 1146-1147 (2001).
5. Palmer KT, Harris EC, Coggon D: Carpal tunnel syndrome and its relation to occupation: a systematic literature review. Occup Med 57(1), 57-66 (2007).
6. Barcenilla A, March LM, Chen JS, Sambrook PN: Carpal tunnel syndrome and its relationship to occupation: a meta-analysis. Rheumatology 51(2), 250-261 (2012).
Competing interests: No competing interests
As Dr Bland has remarked, this article and the rapid responses are providing interesting, meaningful and much needed debate: for the good of all our patients.
Firstly, we must commend and recommend http://www.carpal-tunnel.net/ to carpal tunnel patients and their doctors and we ourselves have spent many an hour reading the updated information and patient perspectives therein, We read Dr Bland's further comments and opinions on the diagnosis of the condition with interest, and obviously defer to his expertise on the neurophysiology.
Our colleague from the USA makes interesting points about 'EDX'; but we would suggest that the true 'gold standard' is exploration of the nerve. Philosophically and economically, we suggest, that gold remains the standard whether or not it is utilized or respected nowadays! For the avoidance of doubt, and to ease any concern of Dr Bland - we are not at all advocating routine exploration of any peripheral nerve but on occasion the discussion of a 'diagnostic decompression' may be required at informed consent(1). In the fifteen years of our practice we can count on one hand the number of times that this approach has been utilized for any of our peripheral nerve entrapment patients - less than 0.5%...
This brings us on to the potential advantages of 'Wide Awake Hand Surgery' (WAHS) in the wider context which we will attempt to cover succinctly in the next few paragraphs. We hope the readership and editor would see that a border perspective on WAHS and peripheral nerve entrapment may be useful here. Firstly, on the importance and specifics of careful clinical assessment of peripheral nerve entrapment; and further, the utility of the scratch collapse (2) and biro (3) tests in peripheral nerve entrapment, not least CTS... When combined with the standard tests described in the article, and bearing in mind of course Dr Bland's correction of the technique for Phalen's testing: we have found the newer tests to be important adjuncts.
We note Dr Bland's comments about Wide Awake Carpal Tunnel Surgery - and would respectfully make a couple of points here from a worldwide hand surgery perspective. Firstly, WAHS without tourniquet and using adrenaline is the next evolution in complex hand surgery. It is routine in Canada, thanks to the work of Prof Lalonde and others, and most UK surgeons are transitioning to the technique. It is true that operating with a tourniquet on the wide awake carpal tunnel patient is entirely possible but there are negatives to this approach; (4,5) and tourniquet pain means that complex/lengthy hand surgery cannot be performed in this way. WAHS has been pioneered by plastic and orthopaedic surgeons from Australia, North America And Europe over the last 10-15 years.
Wide Awake Hand Surgeon Dr E Hager (6,7) has demonstrated how the management proximal median nerve entrapment, and upper limb peripheral nerve entrapment more widely, can be advanced through focussed and specific clinical examination plus a wide awake approach. Our own experience with ulnar tunnel syndrome masquerading as cubital tunnel syndrome in upto 10% of cases (8) is analogous to occult proximal median nerve entrapment, which we have also seen in our own practice.
Finally, in terms of one stop carpal tunnel care we would make the following points:
1. We have used the Southard and Kamath questionnaire as a screening tool for proactive patients who wish to screen themselves via the web, and would not at all advocate this in isolation. The questionnaire is simple, can be integrated into an app or short video easily.
2. One Stop Carpal Tunnel care should not be seen as a 'conveyor belt' approach to carpal tunnel surgery, and Dr Bland's concerns are entirely valid. In our own clinic patients who request one stop carpal tunnel care are assessed regarding their suitability for the approach by the Wide Awake Hand Surgeon and it is made clear throughout that they can defer to multistep treatment at any point. Moreover, a one stop carpal tunnel clinic does not necessarily result in surgery: and we suggest that such a clinic must provide a multidisciplinary approach. In our own clinic this means that a musculoskeletal and exercise medicine doctor is always present and can advise on ergonomics, splinting and nerve mobilization/tendon gliding exercises. This indeed may be all that is required. In addition, access to investigations are always available.
3. In this age of challenging healthcare economic the cost savings of a one stop wide awake approach to carpal tunnel care should not be underestimated - and a cost saving of 50% of tariff is easily achievable.(9).
We commend the authors of the article and all of the rapid responders for highlighting the challenge of delivering best practice carpal tunnel care and suggest that all clinicians must consider:
1. web resources and screening such as at http://www.carpal-tunnel.net/
2. the integration of the full complement of validated clinical tests into the patient pathway
3. A patient-centric 21st Century approach to carpal tunnel care,: presenting all of the evidence-based management options; and facilitating the patient to navigate through all of the diagnostic and therapeutic options which they (and we) may at first find perplexing! (10)
What we do not doubt is that the common objective of providing best practice carpal tunnel care can only be achieved through a multidisciplinary patient-centric approach, and the debate occurring here is absolutely vital in that regard.
1. Bismil QMK, Bismil MSK. Cubital tunnel syndrome with false-negative nerve conduction studies treated with wide awake ulnar nerve decompression via the OSWA pathway. OA Case Reports 2013 Oct 21;2(12):113.
2.Blok RD, Becker SJ, Ring DC. Diagnosis of carpal tunnel syndrome: interobserver reliability of the blinded scratch-collapse test.
J Hand Microsurg. 2014 Jun;6(1):5-7. doi: 10.1007/s12593-013-0105-3. Epub 2013 Sep 22.
3. Kumar A, Bismil Q, Morgan B, Ashbrooke A, Davies S, Solan M. The "biro test" for autonomic dysfunction in carpal tunnel syndrome.
J Hand Surg Eur Vol. 2008 Jun;33(3):355-7. doi: 10.1177/1753193408087231.
4. Wakai A, Winter DC, Street JT, Redmond PH. Pneumatic tourniquets in extremity surgery. J Am Acad Orthop Surg. 2001 Sep-Oct;9(5):345-51.
5. Crews JC, Hilgenhurst G, Leavitt B, Denson DD, Bridenbaugh PO, Stuebing RC. Tourniquet pain: the response to the maintenance of tourniquet inflation on the upper extremity of volunteers. Reg Anesth. 1991 Nov-Dec;16(6):314-7.
6.. Hagert E. Clinical diagnosis and wide-awake surgical treatment of proximal median nerve entrapment at the elbow: a prospective study.
Hand (N Y). 2013 Mar;8(1):41-6. doi: 10.1007/s11552-012-9483-4.
7. Hagert E, Hagert CG. Upper extremity nerve entrapments: the axillary and radial nerves--clinical diagnosis and surgical treatment. Plast Reconstr Surg. 2014 Jul;134(1):71-80. doi: 10.1097/PRS.0000000000000259.
8. Bismil QMK, Lowe S, Viner L, Bismil MSK. The wide-awake approach to ulnar nerve entrapment: results of an integrated one-stop wide-awake surgical pathway. OA Case Reports 2013 Jun 21;2(5):44.
9. Bismil MSK, Bismil QMK, Harding D, Harris P, Lamyman E, Sansby L Transition to total one-stop wide-awake hand surgery service-audit: a retrospective review. J R Soc Med Sh Rep April 2012;3:23 doi: 10.1258/shorts.2012.012019
10. Phaneuf M. [The patient-centered approach, a humanistic pathway for care]. Rev Infirm. 2014 May;201:36-8.
Competing interests: No competing interests
Middleton and Anakwe – Rapid response three
It is good to see that at least this review is stimulating debate and it may be fair to say that the rapid responses so far are in some ways more interesting than the original article. Prof. Descatha clearly agrees with me about the current state of evidence regarding occupational causation and the use of ultrasound imaging but his first paragraph relating to symptoms illustrates an interesting issue regarding how we make the ‘clinical diagnosis’ of CTS.
Essentially this is a diagnosis which should be made by listening to the description of symptoms given by the patient. I originally made this point 14 years ago in a study of which features of the history correlated with the finding of NCS results supporting a diagnosis of CTS,1 and we have pursued this theme through several studies since. Notwithstanding the fact that most diagnoses in ordinary clinical practice are made on the history rather than the examination finding or test results, there is much more literature relating to the utility of clinical signs such as Phalen’s test or to investigations such as NCS than there is studying the individual features in the history which allow us to make the diagnosis. There are some examination findings which are fairly reliable indicators of CTS, notably selective thenar wasting and weakness (though beware thoracic outlet syndrome as pointed out by Drs Alimehmeti and Dashi), and objective sensory loss in a clearly median nerve distribution sparing the palm of the hand. These physical signs however are late features indicating advanced CTS and are strongly correlated with the presence of severe nerve conduction abnormalities and with a poorer surgical prognosis. It is worth looking at the work of Jeffrey Katz who found that impaired function pre-operatively was one of the strongest predictive factors of surgical outcome, and incidentally that Phalen and Tinel signs had no predictive value.2 Our aim should therefore be to detect CTS and treat it before such signs develop and this makes it imperative that we learn how to make the most of the clinical history as a diagnostic tool. Unfortunately, human beings are remarkably inventive in reporting symptoms and although the features highlighted by Prof Descatha are good pointers, we have so far found no single element of the history which is a reliable guide to the diagnosis.
Several attempts have been made to improve the evaluation of the clinical history by non-experts by providing scoring systems for features or questionnaires and it is interesting that Mr Bismil recommends that of Kamath and Stothard.3 This simple questionnaire was originally devised by taking successful surgical outcome as the reference standard for a diagnosis of CTS and I am not aware that it has been independently validated as a diagnostic tool since the publication of the original small, unblinded study of 74 patients, 16 of whom were lost to follow up. We did however test its performance in a large series of patients while devising a newer version of our own history evaluation tool and when using NCS results as the comparator it was clearly inferior. Assessed using the area under a receiver operating characteristic curve as an overall measure of diagnostic performance the latest version of our questionnaire scores 0.79, the original version from 2000 scores 0.73, and the Kamath questionnaire 0.63.4 Although the evaluation of our much longer questionnaire is mathematically complex compared to the simple Kamath scoring, we have made the questionnaire available on the web at www.carpal-tunnel.net so that patients can be left to complete the questionnaire in their own time in a web browser and the site will then provide a quantitative estimate of the probability of CTS. We have recently validated this in its web based form5 and I am now engaged in evaluating whether my own attempts to interpret the patient history as represented by the questionnaire are any better than those of our statistical and neural network algorithms – so far the results are a dead heat.
As well as advocating the use of a demonstrably inferior diagnostic tool Mr Bismil is keen to promote the advantages of ‘wide awake’ surgery and ‘one-stop’ carpal tunnel care. I would like to take issue with both. I think it is fair to say that the vast majority of carpal tunnel surgery in the UK is done with the patient ‘wide awake’ – very few procedures requiring even mild sedation, let alone general anaesthesia, and in fact the only element of the description of his surgical method which is somewhat unusual is the substitution of low dose adrenaline for the use of a tourniquet as a way of reducing bleeding at the operation site. The use of a tourniquet alone does not in any way preclude carrying out carpal tunnel surgery on an out-patient basis and the majority of our patients, who are operated in primary care, are in and out of the practice in an hour on the day of surgery despite the routine use of a tourniquet. I do not think that the method being described by Mr Bismil really warrants a new name as being some radically different form of surgery – this is just standard open carpal tunnel decompression without a tourniquet.
The matter of ‘one stop’ care is more serious. When this phrase is used by surgeons it usually means that the patient is referred from primary care and attends a clinic at which a clinical history and examination is performed, some form of investigation ranging from nothing through to comprehensive ultrasound and nerve conduction studies are performed, and then patients who are thought to have CTS are offered immediate surgery and it is carried out on the spot. Such clinics are, I believe, predicated on the mistaken surgical belief, promulgated earlier in this discussion by Drs Ring and Menendez, that all patients with CTS need surgery. One stop clinics run the risk of precipitate surgery in patients who may not actually need it.
Could I please ask Dr Coebergh to give us a little credit as neurophysiologists for not overstating the meaning of our tests. I too regularly hear in my own clinic the comment from patients, “the tests showed I haven’t got CTS” – when I know perfectly well that when we saw the patient previously we went to some lengths to try and explain the concept of false negative results to the patient. The problem here is not usually one with the neurophysiology report – I and my colleagues mostly take care to express our conclusions in such a way that they do not read as ‘ruling out’ the diagnosis, though I cannot speak for some of the nerve conduction studies provided by people unqualified in clinical neurophysiology. As Dr Ashworth points out, we expect anyone trained in medicine to be fully aware of the concepts of false positive and false negative test results and to treat lab reports accordingly.
1. Bland JDP. The value of the history in the diagnosis of carpal tunnel syndrome. J Hand Surgery 2000;25B(5):445-50.
2. Katz JN, Losina E, Amik BCI, et al. Predictors of outcomes of carpal tunnel release. Arthritis Rheum 2001;44:1184-93.
3. Kamath V, Stothard J. A clinical questionnaire for the diagnosis of carpal tunnel syndrome. J Hand Surgery 2003;28B(5):455-59.
4. Bland JD, Weller P, Rudolfer S. Questionnaire tools for the diagnosis of carpal tunnel syndrome from the patient history. Muscle Nerve 2011;44(5):757-62.
5. Bland JD, Rudolfer S, Weller P. Prospective analysis of the accuracy of diagnosis of carpal tunnel syndrome using a web-based questionnaire. BMJ open 2014;4(8):e005141.
Competing interests: No competing interests
Writing a review of any kind is hard work and clearly Middleton and Anakwe have put considerable effort into this narrative review of carpal tunnel syndrome (CTS) for which I thank them. CTS is a surprisingly complex condition where almost every aspect of the condition is hotly debated from its etiology and pathophysiology, its demographics and clinical diagnosis through to treatment and management. What we do know is that is it very common, it is often distressing and painful to patients, it does cause significant disability and work loss, and there is a very wide variety of opinions in the medical and non-medical fields about how to management this condition (Google 'CTS treatment' for some indication - 7.5 million hits as of now). It is unfortunate then that I feel the BMJ has missed an opportunity here to provide a more balanced and evidence based review that might have provided a bit more clarity.
Many excellent points have already been made in the rapid responses but I'll make three points on electrodiagnostic (EDX) testing that haven't been touched upon yet. Firstly I'd be grateful if anyone could please explain to me why there seems to be so much resistance to ordering EDX tests on patients with numb hands? My surgical colleagues in North America seem extremely keen on having their patients accurately diagnosed by what is still one of the best available tests for peripheral nerve disorders particularly before they operate1. Perhaps some of them can still remember the situation prior to the 1960's before the advent of EDX testing when we were led to believe that patients presenting as Middleton and Anakwe outlined in their review in fact had brachial plexus lesions, commonly known as thoracic outlet syndrome 2. Countless patients would have undergone needless scalenectomies and first rib removal prior to EDX testing pinpointing that the problem was in the wrist in the median nerve and not in the brachial plexus in the neck 3. Even to this day we still see almost a fanatical defense of what we now know is an extremely rare condition and it seems that Alimehmeti and Dashi (rapid responses) would have us once again roll back the clock.
Secondly there is without doubt a 'false negative' rate with EDX testing......i.e. patients that probably have CTS but in whom the EDX studies are normal. That is the inevitable result of having to decide on a cut off for a 'normal' range of values and every single diagnostic test in medicine and surgery will have a false positive and false negative rate. To claim that a test is in some way faulty because it has some patients who falsely test negative shows an lack of understanding of the metrics of diagnostic testing.
Finally there is a considerable misunderstanding around the term 'gold standard' when applied to a diagnostic test. A gold standard test is not a definitive test that establishes a diagnosis in absolute terms beyond all doubt, a gold standard is simply the best available test that we have at that time (gold standard tests are typically replaced by better ones over time) and in that place (certain tests might not be available in that particular health system) 4. The 'Gold standard' itself (borrowed from economics) was abandoned by President Nixon in 1971 implying that even gold itself was not absolute!
I would argue that EDX testing is the gold standard test for CTS. It will tell us which nerve(s) is(are) affected, where along the nerve, how bad and what type of damage, rule out other differential disorders, prognosticate, determine treatment effectiveness, and provide an objective means to follow patients. It takes 20min to perform, is extremely well tolerated by patients, and is considerably cheaper than many other tests that don't provide a fraction of the information that EDX testing does. I would suggest that when available it should be obtained on all patients who fail to respond to initial conservative management (such as wrist splints) after a month or so, and especially on all patients who are contemplating surgery or who are participants in any clinical trial.
1. Keith MW, Masear V, Chung KC, et al. American Academy of Orthopaedic Surgeons Clinical Practice Guideline on diagnosis of carpal tunnel syndrome. The Journal of bone and joint surgery. American volume. Oct 2009;91(10):2478-2479.
2. Pfeffer GB, Gelberman RH, Boyes JH, Rydevik B. The history of carpal tunnel syndrome. J Hand Surg Br. Feb 1988;13(1):28-34.
3. Simpson JA. Electrical signs in the diagnosis of carpal tunnel and related syndromes. Journal of neurology, neurosurgery, and psychiatry. Nov 1956;19(4):275-280.
4. Claassen JAHR. The gold standard: not a golden standard. Vol 3302005.
Competing interests: I use neurophysiological testing and ultrasound to diagnose patients with peripheral nerve disorders and other neuromuscular diseases
This review limits itself unnecessarily in its audience. It omits to mention that the patients commonly present (and outside the UK are even managed) to neurologists, neurosurgeons, neurophysiologists and also commonly to rheumatologists.
I fully support the comments of Dr Bland below but as a neurologist would like to stress one point that might help patients in the UK. From the selection bias as a neurologist I very frequently encounter patients who say 'I do not have carpal tunnel since the EMG was normal'. I have argued for a health warning on the neurophysiology report: EMG can be negative for carpal tunnel syndrome and predicts chances of successful surgery. Carpal tunnel syndrome is a clinical diagnosis with neurophysiological (or ultrasound) support.
This would enable general practitioners, orthopaedic surgeons and other that request EMG but are not trained in its interpretation to help serve patients better. I can highly recommended www.carpal-tunnel.net as a resource.
Dr Jan Adriaan Coebergh
Competing interests: No competing interests
In our practice we see carpal tunnel patients with paresthesia predominant to the third and fourth fingers accompanied with hypotrophy of the thenar eminence.
In such cases we suggest a more accurate physical examination to search for elements of thoracic outlet syndrome. We have seen cases of double crash syndrome of simultaneous carpal tunnel and thoracic outlet syndromes as well.
In such cases the patients are sent for a careful neurophysiological examination to possibly distinguish elements of both suspected syndromes.
In very rare cases where thoracic outlet syndrome was predominant, we did a supraclavicular decompression of middle and lower trunks that were discovered to be under repeated pulsatile compression of subclavian artery. The long term follow-up did not reveal any carpal tunnel complaints to reappear.1
In a clinical review of carpal tunnel syndrome we suggest that thoracic outlet syndrome should be included in the differential diagnosis.
1) R.Alimehmeti, F. Dashi, M. Demneri, M. Petrela. Surgical treatment of thoracic outlet syndrome. Letter to the editor. Medical Journal of Dr D.Y. Patil University, July-September 2013, Vol.6(3):346-7. Doi 10.4103/0975-2870.114666. ISSN: 0975-2870.
Competing interests: No competing interests
Whilst presenting an informative updated review article on CTS, as other responders have noted, there are some notable omissions including: the role of ultrasound imaging; the steady emergence of one stop clinics for CTS; the utility of the Stothard and Kamath scoring system (1), especially to facilitate one stop care; but most significantly, we believe, the evolution of hand surgeons worldwide to wide awake carpal tunnel surgery (2).
Wide Awake Hand Surgery requires the hand surgeon to 'delete' (in the words of wide awake hand surgery pioneer Prof Don Lalonde) the tourniquet and her or his anaesthetist (with the help of low dose adrenaline as a vasopressor)! Further, wide awake carpal tunnel release is performed without general anaesthesia, regional anaesthesia, tourniquets or sedation. We realise that the emphasis of the review is not upon carpal tunnel surgery techniques per se, however, it is important for the readership to be aware that wide awake carpal tunnel release is steadily becoming the standard surgical procedure worldwide. In the UK this has important implications for all hand surgery patients (and their doctors) because of the substantial cost savings a (one stop) wide awake approach can enable:(3) facilitating a streamlined patient pathway(3); which may enable CCGs to continue to offer carpal tunnel care solely based on clinical need rather than according to budgetary constraint.
For an individual patient, the wide awake advantage of the moving sensate hand (as well as the avoidance of tourniquet pain and complications and the uncommon but potentially significant complications of general/ regional anaesthesia and sedation) means that the surgeon can fine tune the carpal tunnel release intra-operatively.
In terms of a one stop wide awake carpal tunnel pathway, we have found ultrasound performed by an expert musculoskeletal radiologist to be an invaluable adjunct to the Kamath and Stothard scoring system (delivered remotely via web video or apps) , focussed clinical examination and robust informed consent. For the wide awake hand surgeon: the anatomical information that ultrasound provides, plus the potential ease of integrating this modality into a one stop pathway, can be extremely valuable.
The clinical features remain the key for the diagnosis this clinical syndrome. False positives and false negatives are an issue with all investigations for what is, primarily a clinical diagnosis: but what ultrasound will always provide is patient specific anatomical information.
Any doctor, patient or healthcare practitioner who requires more information on wide awake hand surgery is invited to contact the Worldwide Awake Hand Surgery Group
or alternatively to search Pubmed for the many publications on wide awake hand surgery by Lalonde et al.(4,5)
1. Kamath V, Stothard J. A clinical questionnaire for the diagnosis of carpal tunnel syndrome. J Hand Surg Br. 2003 Oct;28(5):455-9. Erratum in: J Hand Surg [Br]. 2004 Feb;29(1):95.
2. Löw S, Herold D, Eingartner C. Handchir Mikrochir Plast Chir. [The "wide-awake approach" - efficiency and patient safety in carpal tunnel releases. 2013 Oct;45(5):271-4. doi: 10.1055/s-0033-1355333. Epub 2013 Oct 2.
3. Bismil M, Bismil Q, Harding D, Harris P, Lamyman E, Sansby L.Transition to total one-stop wide-awake hand surgery service-audit: a retrospective review. JRSM Short Rep. 2012 Apr;3(4):23. doi: 10.1258/shorts.2012.012019. Epub 2012 Apr 16.
4. Davison PG, Cobb T, Lalonde DH.The patient's perspective on carpal tunnel surgery related to the type of anesthesia: a prospective cohort study. Hand (N Y). 2013 Mar;8(1):47-53. doi: 10.1007/s11552-012-9474-5.
5. Lalonde D. How the wide awake approach is changing hand surgery and hand therapy: inaugural AAHS sponsored lecture at the ASHT meeting, San Diego, 2012. J Hand Ther. 2013 Apr-Jun;26(2):175-8. doi: 10.1016/j.jht.2012.12.002. Epub 2013 Jan 5.
Competing interests: No competing interests
I read with a particular interest the review by Drs Middleton and Anakwe about carpal tunnel syndrome (CTS). Unfortunately, such as other colleagues before (including Dr Bland who wrote the previous review (1)), different aspects on diagnosis, etiology and subsequent treatment are missing and must be added.
For diagnosis, description of possible symptoms is interesting of the box 1, but patients are rarely able to clearly describe the precise distribution of the symptoms and the typical description is rare.(2) However, sensory disturbances from the palm to the fingertips (including the middle finger), with fluctuating level of symptoms with exacerbation at night
and/or partial relief of symptoms by changing hand posture or shaking the hand, and radiating to the elbow, are highly suggestive.(3) In contrast, isolated hand pain confined to the ulnar or dorsal aspect of the hand is unlikely to correspond to CTS.(4)
Imaging is not generally performed to establish the diagnosis of CTS, although MRI and X-ray can be useful in the differential diagnosis of hand pain. Ultrasound is however, now well established and can detect subtle changes in the width of the median nerve as it passes underneath the flexor retinaculum and, although these signs are not pathognomonic, they can add weight to the diagnosis in doubtful cases.(5)
Work exposure is also a significant risk factor among manual workers. Blue-collar workers involved in manufacturing, construction, meat- and fish-processing industry, and in forestry work with chain saws are mostly likely to develop CTS, together with lower-grade white-collar women working in personal service industries.(6) Forceful hand exertion and combination of high strain (high levels of hand-arm vibration, prolonged work with a flexed or extended wrist, high requirements for hand force, high repetitiveness), were consistently associated with incident CTS,(7–9) whereas keyboard and computer use are not.(10) This is important because in cases with high physical exposure tasks should be discussed with the workers (e.g. mix work patterns, change tools and postures).(11) Subjects with highly probable work-related hand pain or for whom working conditions cannot be adjusted, should be referred to an occupational health specialist.(12)
1 Bland JDP. Carpal tunnel syndrome. BMJ 2007;335:343–6.
2 Burke FD, Ellis J, McKenna H, et al. Primary care management of carpal tunnel syndrome. Postgrad Med J 2003;79:433–7.
3 Calfee RP, Dale AM, Ryan D, et al. Performance of simplified scoring systems for hand diagrams in carpal tunnel syndrome screening. J Hand Surg Am 2012;37:10–7.
4 Graham B, Regehr G, Naglie G, et al. Development and Validation ofDiagnostic CriteriaforCarpal Tunnel Syndrome. JHand Surg(USA) 2006;31:919.
5 Descatha A, Huard L, Aubert F, et al. Meta-analysis on the performance of sonography for the diagnosis of carpal tunnel syndrome. Semin Arthritis Rheum 2012;41:914–22.
6 Palmer KT, Harris EC, Coggon D. Carpal tunnel syndrome and its relation to occupation: a systematic literature review. Occup Med (Lond) 2007;57:57–66.
7 Van Rijn RM, Huisstede BM, Koes BW, et al. Associations between work-related factors and the carpal tunnel syndrome--a systematic review. ScandJ Work EnvironHealth 2009;35:19–36.
8 Spahn G, Wollny J, Hartmann B, et al. [Metaanalysis for the Evaluation of Risk Factors for Carpal Tunnel Syndrome (CTS) Part II. Occupational Risk Factors]. Z Orthop Unfall 2012;150:516–24.
9 Harris-Adamson C, Eisen EA, Kapellusch J, et al. Biomechanical risk factors for carpal tunnel syndrome: a pooled study of 2474 workers. Occup Environ Med Published Online First: 16 October 2014. doi:10.1136/oemed-2014-102378
10 Mediouni Z, de Roquemaurel A, Dumontier C, et al. Is carpal tunnel syndrome related to computer exposure at work? A review and meta-analysis. J Occup Environ Med 2014;56:204–8.
11 Palmer KT. Carpal tunnel syndrome: the role of occupational factors. Best Pract Res Clin Rheumatol 2011;25:15–29.
12 Saint-Lary O, Rébois A, Descatha A. Carpal Tunnel Syndrome in Workers. submitted
Competing interests: Editor in chief of Archives of occupational and environamental disorders (http://www.journals.elsevier.com/archives-des-maladies-professionnelles-et-de-lenvironnement/)
I would also like to make one or two points in response to issues raised by the early rapid responses.
Amyloidosis. – The cardiologists are correct that amyloidosis is a known cause of CTS and a potentially serious disease which can be missed. However the hereditary amyloidoses are rare disorders and senile and light chain amyloidosis are comparatively rare compared to CTS. The fact that an uncommon disorder is frequently complicated by a common one does not mean that screening of all cases of the common disorder for the rare one is warranted. We do not check all CTS patients for acromegaly and the vast majority of carpal tunnel decompressions are done without taking tissue samples for histology so doing this to stain for amyloid would be a significant use of resources.
Small tunnels. – Menendez and Ring castigate Middelton and Anakwe for failing to reference evidence for spontaneous remission of CTS whereas they did in fact quote the study of untreated CTS by Padua et al. They themselves assert that the main cause of CTS is a congenitally narrow carpal tunnel and therefore by their thinking the condition demands surgical management to correct this inherited deformity. They block quote 10 references to support this statement, including, curiously, my own study of the population prevalence of CTS in East Kent. These references cover a wide range of topics but so far as I can see none of them conclusively demonstrate that a congenitally narrow canal is the primary cause of CTS and my own reading of the literature on this subject suggests that a variety of CT, MRI and ultrasound imaging studies have failed to reach any definite consensus that CTS patients have smaller tunnels, or perhaps more important, a different ratio of tunnel size to tunnel contents. Women do have smaller wrists than men, and smaller carpal tunnels, but if the contents of the tunnel are smaller in proportion this may not matter. I would appreciate it if Menendez and Ring could reveal exactly which evidence they are quoting.
1. Padua L, Padua R, Aprile I, et al. Multiperspective follow-up of untreated carpal tunnel syndrome: A multicenter study. Neurology 2001;56(11):1459-66.
2. Bland JDP, Rudolfer SM. Clinical surveillance of carpal tunnel syndrome in two areas of the United Kingdom, 1991-2001. J Neurol Neurosurg Psychiatry 2003;74:1674-79.
Competing interests: No competing interests
Middleton and Anakwe have given us a lengthy overview of the investigation and treatment of carpal tunnel syndrome. This topic has been covered in a similar way twice before in the last few years[1 2] and it is interesting to see what is new in the current article. It would appear from the majority of this article that the answer is “not very much” as very little of the advice given has changed. Carpal tunnel syndrome is still described as a clinical diagnosis; physical provocative “tests” (Phalen, Tinel, Durkan) are given considerable prominence as aids to diagnosis and comprehensively illustrated, encouraging non-experts to use them; the usual lists of differential diagnoses and possible aetiological factors are given; nerve conduction studies are described as not necessary for initial diagnosis in primary care; steroid injection is portrayed as a generally temporary measure to be used once only; and surgery is broadly described as successful, with even the 7% incidence of scar pain and 18% incidence of pillar pain being qualified by a statement – may persist for up to two years – which tends to imply that even these problems will go away eventually if the patient waits long enough. The rapid responses so far raise some interesting issues though.
It is true that there is not a lot of change in our view of CTS since 2007 but there are some interesting new findings. A few of them are mentioned in this review but the way in which they impact on everyday management of CTS is rather underplayed. Furthermore, some of the components of the thumbnail image of CTS summarised above should now be challenged.
Aetiology and occupation. – 7 years ago it was common to find CTS described as an occupational illness and there remains a substantial industry in some parts of the world based around industrial compensation claims for CTS and workplace modification to try and prevent or treat it. Middleton and Anakwe correctly point out that evidence has been accumulating for some time to suggest that hand use plays a smaller part in the aetiology of CTS than previously thought. However, this evidence takes two forms. Firstly several studies have shown that the popular press image of CTS as related to keyboard use is demonstrably wrong.[3-5] On the other hand several systematic reviews of the literature have concluded that high-force, repetitive work, especially with vibrating tools, does carry a small increase in the risk of CTS.[6-8] It is therefore now possible to do rather better than simply saying that “evidence for occupation as a causative factor for carpal tunnel syndrome is weak” – we can much more definitively say that strenuous, repetitive manual occupations with vibration exposure carry a modestly increased risk of CTS, whereas keyboard use is irrelevant. This represents a change from 2007 when I wrote that the role of occupational and recreational hand use in conversation remains controversial.
Phalen’s test. – The illustration in figure 4 is not Phalen’s test. Phalen illustrated his wrist flexion test in his summary paper in 1966  and described the manoeuvre in the text as “allowing the wrists to drop into complete flexion”. Middleton and Ankawe in contrast have illustrated forced flexion of the wrist which will increase the false positive rate.
Steroid injection. – In 2007 the available evidence for steroid injection clearly demonstrated superiority to placebo only up to one month post injection. This Cochrane review is currently being revised and it is perhaps a pity that Middleton and Anakwe did not wait for the revision. They have however mentioned the most important trial of steroid injection to appear in the interim. Unfortunately they do not present its conclusions in full. It is true that 75% of the patients had surgery within a year of randomization and that there was no difference in subjective severity of symptoms between the steroid and placebo groups at 1 year. However, this analysis was carried out on an intention to treat basis and the lack of difference in subjective symptom scores between the groups at one year only reflects the fact that the majority of each group had had surgery by that point. The more interesting result of this study lies in the incidence of surgery in the three groups. By one year, 92% of the placebo group, 81% of the 40mg methylprednisolone group, and 73% of the 80mg methylprednisolone group had opted for surgery. These rates of surgery in the steroid treated groups were significantly lower than that in the placebo group. It should be remembered that the patients entered into this trial were relatively young (mean age 48 years), had already failed an 8 week trial of splinting, and had been referred to a renowned Swedish surgical clinic. This cohort of patients were essentially destined for surgery and had they been treated by Menendez and Ring (rapid responses) they would undoubtedly all have been operated. Seen in this context the fact that a quarter of the patients given the very inexpensive, very safe, very convenient intervention of 80mg Methyprednisolone had not in fact required surgery after a year suggests that there may be more of a case to be made for injection as a treatment than it would appear from this review.
Repeat injection. – We are told that the use of second (or subsequent) injections is not supported by good evidence. It is true that there are no high quality placebo controlled randomized trials of a second injection. However, repeat injection is widely practiced anyway in primary care and rheumatology and we have recently published an observational study which suggests that second injections are just as effective overall as the first one. There are other observational studies which are beginning to suggest that a policy of repeated steroid injection may be a viable treatment choice for some patients. A recent study in Scotland of 824 patients who, in contrast to the Swedish steroid trial, had not been preselected as likely surgical candidates and who had steroid injection as a primary treatment found that only 33% of these had resorted to surgery after 5 years of follow-up. 372 of these patients had a second injection during the follow up period with 308 (83%) of them obtaining satisfactory relief of symptoms, very similar to the generally reported rate of response to a first steroid injection. (See also commentary by McEachan) In yet another study, 38% of a group of 120 patients, some with quite severe CTS, were successfully treated with one, two or three injections over a period of one year. It is now true to say, I think, that there is enough evidence of the efficacy of repeat injection to justify a serious comparison of a policy of long-term management with steroid injection compared to surgery. Whatever figures one believes for the complication rates of surgery and injection it is quite clear that injection is the safer, cheaper, and more convenient option and deserves more serious consideration than it is given by writers such as Menendez and Ring (rapid responses) who repeat the old scare story about conservatively treated patients presenting later with irreversible nerve damage. In our recent study the severity of CTS at re-presentation with relapse after the first injection was no worse than prior to the first injection.
Ultrasound. – All of the above are at least mentioned by Middleton and Anakwe. The review however makes no mention whatever of the revolution in median nerve imaging over the last 20 years. High resolution ultrasound imaging has similar diagnostic capabilities for confirming or refuting a diagnosis of CTS to nerve conduction studies,[16-19] can demonstrate structural abnormalities of aetiological relevance in some cases, and is invaluable in the assessment of failed carpal tunnel surgery. It is also inexpensive and painless but despite these advantages there remain good reasons for carrying out nerve conduction studies. Each investigation can provide information which the other cannot.
Electrophysiology. – The role of nerve conduction studies is indeed still argued over but the guidelines from the BSSH referred to have now been withdrawn pending revision and the joint guidance to commissioners issued by the BSSH, RCS and BOA reference only an eclectic set of papers, none of which are concerned with analyzing the utility of electrophysiology in CTS. Middleton and Anakwe do not appear to make a firm recommendation for when NCS should be carried out. I would suggest that they should always be done before surgery and preferably before injection where readily available. Pre-operative NCS should be done within the 6 months preceding the operation – results from 5 years previously are useless. One of the important reasons for doing them is to aid in the assessment of patients who do not get the expected benefit from surgery. As pointed out by Menendez and Ring, NCS mostly remain abnormal after surgery. That does not mean that they do not change, and successful surgical decompression is strongly correlated with an improvement of two Canterbury grades in the NCS when compared with the pre-operative studies. Failure to demonstrate such an improvement is strongly suggestive of incomplete decompression or some other surgical failing but it is impossible to assess whether there has been a change without the pre-operative tests.
1. Bland JDP. Carpal tunnel syndrome. Brit Med J 2007;335:343-46.
2. Aroori S, Spence RAJ. Carpal Tunnel Syndrome. Ulster Med J 2008;77(1):6-17.
3. Stevens JC, Witt JC, Smith BE, et al. The frequency of carpal tunnel syndrome in computer users at a medical facility. Neurology 2001;56:1568-70.
4. Atroshi I, Gummesson C, Ornstein E, et al. Carpal tunnel syndrome and keyboard use at work. Arthritis Rheum 2007;56(11):3620-25.
5. Thomsen JF, Gerr F, Atroshi I. Carpal tunnel syndrome and the use of computer mouse and keyboard: A systematic review. BMC Musculoskeletal Disorders 2008;9:134.
6. Barcenilla A, March LM, Chen JS, et al. Carpal tunnel syndrome and its relationship to occupation: a meta-analysis. Rheumatology (Oxford) 2012;51(2):250-61.
7. van Rijn RM, Huisstede BM, Koes BW, et al. Associations between work-related factors and the carpaltunnel syndrome--a systematic review. Scand J Work Environ Health 2009;35:19-36.
8. Palmer KT, Harris EC, Coggon D. Carpal tunnel syndrome and its relation to occupation: a systematic literature review. Occup Med (Lond) 2007;57:57-66.
9. Phalen GS. The carpal-tunnel syndrome: seventeen years' experience in diagnosis and treatment of six hundred and fifty-four hands. J Bone Joint Surg 1966;48A:211-28.
10. Marshall S, Tardif G, Ashworth N. Local corticosteroid injection for carpal tunnel syndrome. Cochrane Database Syst Rev 2002(4).
11. Atroshi I, Flondell M, Hofer M, et al. Methyprednisolone Injections for the Carpal Tunnel Syndrome: A randomized Placebo-Controlled Trial. Ann Int Med 2013;159:309-17.
12. Ashworth NL, Bland JDP. Effectiveness of second corticosteroid injections for carpal tunnel syndrome. Muscle Nerve 2013;48(1):122-26.
13. Jenkins PJ, Duckworth AD, Watts AC, et al. Corticosteroid injection for carpal tunnel syndrome: a 5-year survivorship analysis. Hand 2012;7:151-56.
14. McEachan JE. Commentary on Berger et al. The long-term follow-up of treatment with corticosteroid injections in patients with carpal tunnel syndrome. When are multiple injections indicated? J Hand Surgery 2013;38E:640-41.
15. Berger M, Vermeulen M, Koelman JHTM, et al. The long-term follow-up of treatment with corticosteroid injections in patients with carpal tunnel syndrome. When are multiple injections indicated? J Hand Surgery 2013;38:634-40.
16. Fowler JR, Gaughan JP, Ilyas AM. The sensitivity and specificity of ultrasound for the diagnosis of carpal tunnel syndrome: a meta-analysis. Clin Orthop Relat Res 2011;469(4):1089-94.
17. Roll SC, Case-Smith J, Evans KD. Diagnostic Accuracy of Ultrasonography VS. Electromyography in Carpal Tunnel Syndrome: A Systematic Review of Literature Review Article. Ultrasound in Medicine & Biology 2011;37(10):1539-53.
18. Descatha A, Huard L, Aubert F, et al. Meta-Analysis on the Performance of Sonography for the Diagnosis of Carpal Tunnel Syndrome. Seminars in arthritis and rheumatism 2012.
19. Tai TW, Wu CY, Su FC, et al. Ultrasonography for diagnosing carpal tunnel syndrome: a meta-analysis of diagnostic test accuracy. Ultrasound Med Biol 2012;38(7):1121-8.
20. Bland JDP. A neurophysiological grading scale for carpal tunnel syndrome. Muscle Nerve 2000;23:1280-83.
Competing interests: No competing interests