Carpal Tunnel

Carpal tunnel syndrome is a form of neuropathic pain relates to the criteria of the International  Association for the Study of Pain (IASP) which defines it as  initiated or caused by a primary lesion or dysfunction of the nervous system.  Neuropathic pain is based on the symptoms (spontaneous or evoked pain, paraesthesia) and signs ( mechanical allodynia, thermal hyperalgesia) which  may relate more closely to mechanisms and therefore be more helpful in identifying appropriate treatment. Patients with neuropathic pain typically describe pain of two types: (i) Constant burning pain (ii) intermittent shooting or electric pain. In addition positive symptoms of paraesthesia, numbness and dysasthesia such as itching, crawling and tingling are highly suggestive of neuropathic pain. Results of neurological examination indicate negative signs of sensory, motor and reflex testing. The pain typically occurs adjacent to a region of sensory disturbance and may begin in weeks, months or years following initial insult to the nervous system (1)..
carpal-tunnel-syndrome

Carpal tunnel syndrome (CTS) is a common peripheral neuropathy, our aim is to review the current literature on carpal tunnel syndrome, its signs and symptoms, diagnosis, differential diagnosis and treatment options, in this case the presentation to our clinic and the outcome of Chiropractic therapy.

In addressing the symptoms and history of the condition of CTS, as clinicians we need to address the age, sex and period of onset. Also needing to clarify the duration and intensity of the condition of which we use the Numerical Rating Scale (NRS) (2). The patient is asked to describe and show where their symptoms are felt. Other setbacks / characteristics would be to assess the ability to hold objects, also would they develop numbness in the hand whilst holding objects.

Other symptoms as does the condition interrupt their sleep pattern (3) would they wake and need to “shake” their hand in attempt to alleviate their  symptoms, this would be disrupting their sleep pattern, leading  to feeling fatigued during the day. As chronic pain is frequently associated with depression and sleep disturbance (4). Do these symptoms occur on a daily basis, does this affect their quality of life.  Do they live at home alone, being in a capacity to look after themselves. Have they used splinting / immobilisation techniques, what are their outcomes, should all be documented.

Noting also of previous assessments / treatment consisting  of consultation with a hand surgeon, confirmation of the condition by way of nerve conduction and electromyography, showing any neurophysiological evidence of median neuropathy.

Surgery has the following results / outcomes (5):
i) Surgical release of the carpal tunnel
ii) Would need up to 6 weeks of incapacity with the use of the hand, with a 90-93% success rate.
iii) Given the choice of a less invasive procedure of cortisone injection into the sheath of the wrist.
iv) Given 7-10% outcome of not being cured, with possible detrimental injury to the median nerve and associated flexor tendons
v) There is a 1/100 chance of suffering an infection.
vi) A 1/500 chance of abnormal reaction to surgery which may cause pain swelling and stiffness in the whole arm
and last 6 months or more and sometimes leave permanent effects

Previous and current medical history is important as conditions such as diabetes can cause patients to succumb to peripheral neuropathies such as CTS as well as previous trauma such as fractures of the hand / wrist. Are they a social drinker or smoker, as this can be detrimental to tissue healing. Their main interests of recreation, sport, hobbies does the condition prevent them from pursuing these activities. General well being and presentation assessing whether they are anxious, depressed, are they co-operative with history taking and want help with her condition. Assessing status of their family relationships or if it is a compensation case / litigation all need to be considered as this can be a hindrance to positive outcomes. Consideration of the type of employment can have some impact, for example if their work is physical this could affect treatment outcomes.

In forming a  pain formulation of the case (6) a barrier to recovery is accepting what procedures are available and their outcomes, having current underlying conditions such as cardiac, are elderly or pregnant can make them a non-candidate for any interventional procedures. Feelings of  helplessness in terms of what to do with their condition, prolonging a positive outcome, further perpetuating  the existing condition leading to fatigue and feelings of depression.

It is important to explain to the patient the treatment offered at our clinic and what procedures are involved to make it effective so that  the patient has a shared understanding of our procedures, that it being non-invasive. Giving a specified time-frame, for two reasons (i) it gives the patient an idea of how Chiropractic treatment works (ii) If the desired outcome is not achieved then treatment would cease, so expectations are met. However the response would be slower and they would have to be patient and allow the programme of treatment to progress as prescribed, consisting of two sessions per week for four weeks which needed to be followed, this would gain their confidence and hence to participate as the aim is to improve the condition and subsequently their quality of life, this would be assessed by:
i) Pain levels, are they lessening, as the treatment is progressing, currently using NRS.
ii) Functional improvement, sleep without being woken up in numbness and pain.
iii) Holding objects pain free and confidently, for example holding the phone without developing numbness and being able to do their hobbies and recreational activities.
iv) Treatment is meeting the financial cost, cost-benefit efficacy as compared to surgery which involves the use of theatre, surgeon, anaesthetist, nursing staff which is a more expensive option.

Sleep is our main objective as this can make the patient feel fatigued and having feelings of depression, as chronic pain is frequently associated with depression, disturbed sleep and concentration difficulties (4). It is important to explain to the patient the activities such as gardening would have to cease to prevent aggravating the condition. The goals of treatment are clarified with the patient, so signs and symptoms would diminish, a specific timeframe is shown and the patient accepting these formulations and meeting their opinion of not wanting surgical intervention if possible.

The prevalence of CTS is 3.8% of the population, women are 3 to 4 times more likely than men to develop the condition and it effects both wrists in 50 % of cases (7). Although uncommon in children or adolescents, the disorder could be caused by an autosomal dominant hereditary factor and mucopolysacharidoses in children.  It is most prevalent between 40-60 years of age. Risk factors are trauma to the wrist, obesity, diabetes, pregnancy-fluid retention, which can result in compression of the median nerve, hormonal disorders related to-hypothyroidism, postmenopausal patients, ovierectomy and hysterectomy (3).

Mechanisms and contributors entails understanding the functional anatomy of the median nerve, (8) it arises by two roots, one from the lateral cord C5-C6-C7, and the other from the medial  cord C8-T1 of the brachial plexus, the roots embrace the third part of the axillary artery uniting either in front or on the lateral side of the artery. The median nerve descends into the arm. The nerve usually enters the forearm between the two heads of the pronator teres. At the wrist the nerve passes deep to the flexor retinaculum to gain to the palm of the hand. Just proximal to the flexor retinaculum the nerve is lateral to the tendons of the flexor digitorum superficialis, but dorsal to the retinaculum it lies immediately deep to the latter and on the anterior aspect of the tendons, in the limited space of the carpal tunnel. The flexor retinaculum (9) is a strong fibrous band that crosses the front of the carpus and converts its anterior concavity into the carpal tunnel through which passes the flexor tendons of the digits and the median nerve. The retinaculum is relatively short measuring 2.5 cm -3cm with a similar breadth. A muscular branch is a short stout nerve that arises from the lateral side of the median nerve , giving a branch to  the flexor pollicus brevis, it gives a branch to the (8) abductor pollicus brevis, further supplying  the opponens pollicus . Further the median nerve then divides into four to five digital branches to the thumb and the radial side of the index finger, and a medial branch which supplies the digital branches to the adjacent sides of the index, middle and ring fingers.  In the digits the branches of the nerve gives off several branches to the skin many which end in lamellated corpuscles and   of the aforementioned digits, and branches to the metacarpalphalangeal and interphalangeal joints of the aforementioned digits.

Branches are also supplied to the fibrous sheaths of the long flexor tendons, to the digital arteries (vasomotor) and to the sweat glands (secretomotor) (8).

Hence from understanding the functional anatomy mechanisms and contributors of CTS involve the median nerve being trapped in the carpal tunnel as a result of oedema, inflammation of the synovial sheaths, changes in the shape of the tunnel (8). Also there are a number of differential diagnosis such as neuropathy of the ulnar nerve, brachial plexus
defects / injury, spinal nerve root defects, neurovascular compression syndromes in the shoulder, multiple sclerosis and processes in the spinal cord (3).  In cases of CTS the symptoms generally consist of unilateral nocturnal paraesthesia in the dermatome of the median nerve (digits I-III including ½ of digit IV). In addition there maybe pain in the hand, wrist and forearm.  CTS is mainly unilateral but it maybe bi-lateral, as the condition progresses symptoms may occur during the day with subjective loss of strength (8). Injury to a peripheral nerve results in a number of changes that may contribute to pain (1) : i) Release of peptides such as substance P and calcitonin gene-related peptide from the distal end of damaged primary afferent nerves. Release of inflammatory mediators and cytokines which may also sensitise nerve terminals. This will lead to peripheral sensitisation of adjacent primary afferents and increase inputs from these fibres.  ii) Alterations in the expression of neutrophins that regulate the structure and function of the nerve. These changes can therefore alter the way that the damaged nerve responds to stimuli and communicates with other nerves. The nerve may even undergo phenotypic switch and large fibres may begin to express peptides found in nociceptive afferents.  iii) Expression of alpha adrenoreceptors at the site of damage and in the dorsal root ganglion may contribute to the development of autonomic features that are a component of CTS, this may result in pathological coupling of sympathetic and primary afferent nerve activity. Receptors on the damaged nerve are responsive to circulating catecholamines and therefore increase in sympathetic activity may result in enhanced activity in primary afferent fibres.

Diagnosis is aided by nerve conduction tests of the median nerve of both hands of the patient are to be considered and is the best predictor of symptom severity and functional status.  When structural defects in the wrist are suspected, a radiograph of the wrist, magnetic resonance imaging scan or ultrasound scan maybe considered (7).

Our physical examination aims at assessing and revealing the following:
i) Cervical range of motion, noting decreased painful movements as well as any referred / radiculopathy.
ii) Palpation of the cervical vertebral segments, as any restriction of the C5-T1 segements can afffect the neurobiology of the origin of the median nerve as explained.
iii) Tinel’s sign is it positive of the median nerve, complaining of paraesthesia?
iv) Deep Tendon Reflex (DTR) testing revealing abnormalities.
v) Sensory testing is it decreased (negative signs) at the distal ends of the 1st, 2nd & 3rd  digits of the hand.
vi) Motor testing neurological levels / nerve roots C5-T1 and their results.

Based on the IASP criteria and physical examination findings CTS can be confirmed.

The efficacy of treatment and management options as indicated by the mechanisms and contributors as well as the pain formulation for this case warrants Chiropractic therapy. More specifically Activator Methods Chiropractic Technique which initiate passive joint movements, resulting in mechanoreceptive stimulation creating pre-synaptic inhibition of nociceptive afferent activity thus diminishing or abolishing pain. Normal joint function can help normalise mechanoreceptive and nociceptive input (10). Activator Methods Chiropractic Technique  was applied  to the appropriate cervical vertebrae / facet joints, carpal bones and to the metacarpophalangeal, proximal interphalangeal and distal interphalangeal  joints of the first 3 digits. In addition ultrasound is be applied to the flexor retinaculum / median nerve, the purpose of ultra sound is reduce inflammation of these tissues / micro-adhesions , tendon syndromes (11).


Efficacy of treatment would aim at showing an overall improvement of the following compared to the original presenting complaints / symptoms such as NRS scores compared initially to current status at the end of the treatment programme. Not waking at night because of numbness, and being able to do physical activities such as gardening other activities. Not dropping objects and holding objects without developing numbness. Re assessing the following:
i) Cervical range of motion, results.
ii) Palpation of the cervical vertebral segments assessing functional status from C5-T1.
iii) Tinel’s sign results.
iv) Deep Tendon Reflex (DTR) testing revealing an abnormalities.
v) Sensory testing  at the distal ends of the 1st, 2nd & 3rd  digits of the hand.
vi) Motor testing neurological levels / nerve roots C5-T1 and their results. .

In a majority of CTS patients the recommended management options are (8) conservative treatment which  include behaviour modifications, medications, including anti-inflammatory drugs and analgesics, immobilisation via splinting or bracing, physical and occupational therapy, oral corticosteroids and ultrasound.  There are indications that local injections with corticosteroids are less effective in the long term than surgical interventions. The surgical option, open or endoscopic carpal tunnel surgery entails greater risks of complications.

Pharmacological treatment of neuropathic pain has relied more on the use of so called adjuvant medications. These include tricyclics antidepressants-amitryptyline, imipramine, nortriptyline, anticonvulsant-gabapentin -neurontins, local anaesthetics-lignocaine patch, NMDA antagonists-ketamine, and alpha-adrenergic agonists-clonidine. Controlled studies demonstrate the best of these drugs will only produce  appositive respons in 50 % of relief of pain. Neural blockade  injection of local anaesthetic and steroid around peripheral nerves/nerve roots. Apart from medications other approaches such as stimulation techniques, spinal drug administration, and ablative techniques (1).

References:
1) Siddall, P. (2008). Module 4: Neuropathic Pain. Graduate Studies in Pain Management. (pp.2-8).
2) Melzack, R. & Katz, J. (2001). The McGill Pain Questionnaire: Appraisal and Current status. In D.C. Turk and R. Melzack (Eds.). Handbook of Pain Assessment (pp.36). Guilford
3)Patjin, J. et. Al. (2011). Evidence-Based Medicine. 11(3). (pp.297-301).
4) Craig, K.D. (1999). Emotions and Psychobiology. In P.D. Wall and R. Melzack (Eds.). Textbook of
(pp. 37-339). Churchill Livingstone:U.K.
5) Hardas, G.M. (2011). Clinical notes. St George Private Hospital.
6) Linton, S.J., Nicholas, M. K. (2008). After assessment, then what? Integrating findings for successful case formulation and treatment tailoring. (pp.95-102).
7) Scanlon, A., Maffei, J. (2009). Carpal Tunnel Syndrome. 41(3). (pp.140-147).
8)Williams, P.L. & Warwick, R. (1986). GRAY’S ANATOMY. Neurology. (pp.1098-1099). Churchill Livigstone.
9) Williams, P.L. & Warwick, R. (1986). GRAY’S ANATOMY. Myology. (pp.583). Churchill Livigstone.
10) Colloca, C. J. (1997). Articular neurology, altered biomechanics and subluxation pathology. In A.W. Fuhr, C.J. Colloca, J.R. Green and T.S. Keller. Activator Methods Chiropractic Technique. (pp.42). Mosby.
11) Ebenbichler, G. (2009). Evidence-based medicine and therapeutic ultrasound of the musculoskeletal system. 68. (pp.543-548).

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