Efficacy Study of Local Steroid Injection and Wrist Splinting for Carpal Tunnel Syndrome
Efficacy Study of Local Steroid Injection and Wrist Splinting for Carpal Tunnel Syndrome
Carpal tunnel syndrome is caused by the compression of median nerve at the wrist where it
 passes through a narrow space called carpal tunnel formed by the wrist bones, ligaments and
 tendons. The common symptoms include numbness and pain over the areas supplied by the median
 nerve namely the thumb, the index finger, the middle finger and the outer part of the ring
 finger. There can be loss of sensation, weakness or muscle atrophy in severe cases. The
 functions of the affected hands may be greatly impaired.

 Carpal tunnel syndrome is very common. It can lead to significant economic impact both to the
 affected individual and the society either by the direct treatment cost and indirectly from
 the working ability loss. Despite the vast burden, there is no consensus regarding its
 treatment so far. Surgery is generally effective and often reserved for severe cases. There
 are many nonsurgical treatment options. Local steroid injection and wrist splinting are among
 the commonest and with more evidence. Local steroid injection into the carpal tunnel can
 reduce the inflammation and swelling. Wrist splinting can maintain the wrist at its neutral
 position where the pressure at the carpal tunnel is the least. However, there are only very
 few studies comparing these two treatments directly.

 Patients complaining of finger numbness who have been confirmed to have carpal tunnel
 syndrome by nerve conduction test are invited to participate in the study. The patients who
 agreed to be recruited are asked about their basic informations and the details of the carpal
 tunnel syndrome symptoms. Their hands will be examined. They are asked to fill in a
 questionnaire specific for assessing the symptom severity and the functional status of
 patients with carpal tunnel syndrome. They will then be assigned to one of the two treatment
 groups randomly and receive the respective treatment. They need to come back for follow-up at
 one month and to fill in the questionnaire again.

 The study hypothesis is local steroid injection is more effective than wrist splinting in
 treating carpal tunnel syndrome.
Carpal tunnel syndrome (CTS) is caused by the pressure and consequent compression on the
 median nerve within a confined anatomical area at the wrist referred to as the carpal tunnel.
 It is very common and has an important socio-economic impact. The prevalence of CTS in the UK
 is 7-16%. Its incidence has been estimated at 88-125 per 100,000 in USA. Economic
 consequences include the direct financial implications of treatment and the indirect cost of
 absenteeism from the workplace. The median number of days away from work for CTS is among the
 highest at 27 days. In the US in 1995, between 400,000 and 500,000 patients underwent
 surgical decompression. This equates to an economic cost of in excess of $2 billion. CTS and
 hearing loss was found to account for more morbidity, measured by cases and working days
 lost, than any other illness in the US working population. CTS may also occur as a work-
 related disorder leading to compensation claims.

 Despite the vast burden of the disease, there is no consensus regarding its best management.
 Surgical treatment is generally preferred in severe cases of CTS. A Cochrane review
 investigating surgical treatment of CTS showed surgical treatment relieves symptoms
 significantly better than splinting, but no conclusion could be drawn in people with mild
 symptoms and if surgical treatment is better than steroid injection. On the other hand,
 surgical treatment is relatively costly and carries risks of significant complications that
 may last several months and give rise to further work absence. In addition, the waiting time
 for surgery is usually long.

 For non-surgical interventions many modalities have been trialed but only a few have shown
 discernable benefits. Local steroid injection and wrist splinting are among the most popular
 options. They are commonly employed in mild to moderate cases of CTS. For severe cases, they
 can also offer relief of complaints during the waiting period for surgery or when there are
 contra-indications for surgery. Systematic reviews of randomized controlled trials have
 concluded that local steroid injection provides greater clinical improvement at one month
 compared with placebo and that there is weak evidence that a splint worn at night is more
 effective than no treatment in the short term. However, the number of studies that compare
 the two methods is limited, and they are mostly either retrospective in design or prospective
 but non-randomized. Two randomized controlled trials comparing local steroid injection and
 splinting found respectively that local steroid injection does not significantly improve
 clinical outcome compared to anti-inflammatory drugs and splinting and that injections of
 steroids are ineffective. However, the conclusions of these two studies are limited either by
 a small sample size or the lack of a validated outcome measure.

 We would like to conduct a prospective randomized clinical trial comparing the efficacy of
 local steroid injection and splinting in patients with CTS using the Boston Carpal Tunnel
 Questionnaire as outcome measure with a 4-week follow-up.

 Patients attending the medical clinic of a local hospital (Kwong Wah Hospital) complaining of
 finger or hand numbness are referred to the electro-neuro-diagnostic unit for nerve
 conduction test. Consecutive patients with clinical and electrophysiological features of CTS
 are invited to participate in the study. Clinical features are pain, paresthesia or weakness
 in the median nerve distribution for at least 3 months. The neurodiagnostic criteria are
 based on the American Academy of Neurology summary statement, which further classifies the
 abnormalities as follows: (1) mild abnormality, i.e., abnormal comparative tests or prolonged
 median distal sensory latency (DSL > 3.5 ms) but normal median distal motor latency (DML);
 (2) moderate abnormality, i.e., prolonged median DSL and DML (⩾4.2 ms); and (3) severe
 abnormality, i.e., absence of median sensory nerve action potential and prolonged median DML
 or absent compound muscle action potentials.

 Patients are excluded if they have any recognized causes of CTS including inflammatory
 arthritis, diabetes mellitus, hypothyroidism, renal failure, polyneuropathy and history of
 significant local trauma. Other exclusion criteria include age younger than 18 years,
 previous treatment of CTS and pregnancy. Patients with motor impairment or thenar muscle
 atrophy are also excluded and they will be referred to the Orthopedic unit for assessment of
 surgery.

 All potential participants are informed of the objectives and procedures of this study, as
 well as the possible complications. The patients who have given informed consent are
 interviewed by a single investigator within 4 weeks of the NCV. Their demographical data
 including age, gender and body mass index (BMI) are recorded. The duration of the symptoms,
 medical comorbidities and employment status are documented. Examination of the hand is
 performed by the same investigator focusing on the sensory loss at the tips of digits 1, 2,
 3, or the medial side of digit 4, and weakness or atrophy of the abductor pollicis brevis or
 opponens pollicis. Sensation is assessed using pinpricks. Sensory and motor function is
 recorded to be either normal or impaired. In patients with bilateral CTS, the most
 symptomatic hand will be included. In case both hands are equally symptomatic, the dominant
 hand will be included. Recruited patients are asked to complete the Boston Carpal Tunnel
 Questionnaire (BCTQ). They will then be allocated to one of the two treatment arms according
 to the randomization procedure.

 Patients are randomly assigned to one of the two treatment groups using sequentially numbered
 opaque sealed envelopes (SNOSE). Allocation concealment is maintained before the
 randomization procedure.

 The local injection of steroid is performed by the same investigator after the randomization.
 Using a sterile technique, 20mg depomedrol premixed with lidnocaine is injected using a
 25-gauge x 5/8" needle. The needle is inserted medially to the palmaris longus tendon at the
 distal palmar crease in the wrist at an angle of 45-degree to the forearm. The steroid is
 injected at approximately 1cm below the skin. The needle will be repositioned if there is any
 resistance to injection, or any pain or paraesthesia in the median nerve territory.

 Minor complications of steroid injection include local pain, bleeding, skin depigmentation,
 skin atrophy and digital ischemia. Concerns that nerve or tendon injury may result from
 steroid injection appear to be unfounded. In 28 studies of local steroid injection treatment
 involving 1981 hands in total there have been no reported instances of such injury,
 suggesting that the risk is very low. There is a small risk of infection.

 After randomization, the hands of the patients in the splinting group are splinted in neutral
 position with standard cotton-polyester splint. Patients are encouraged to use the splints
 during nighttime whenever possible for 1 months.

 The potential side effects of splinting include discomfort due to the local pressure and
 allergic response to the splint material.

 The primary outcome measure is clinical improvement at one month. The Boston Carpal Tunnel
 Questionnaire (BCTQ) is used as the measure assessing clinical response. It is a
 self-administered disease-specific questionnaire for assessing severity of symptoms and
 functional status based on two scales. The symptom severity scale (SSS) is comprised of 11
 questions, and the functional status scale (FSS) is comprised of 8 questions. The assessment
 of each question is on a scale of 1-5 points, in which 1 indicates no symptom, and 5
 indicates severe symptoms. Each scale generates a final score (sum of individual scores
 divided by number of items) which ranges from 1 to 5. The evidence base of the psychometric
 properties indicates that the BCTQ is a valid, reliable, responsive and acceptable instrument
 and should be included as a primary outcome measures in CTS intervention trials. The
 questionnaire has Chinese validity.

 Patients are interviewed at one month after randomization. They are asked to complete the
 BCTQ and rate the satisfaction of treatment each time. Duration of sick leave for employed
 patients, concomitant use of analgesics, and adverse effects are recorded.

 As all participants have symptoms of CTS and will receive valid active treatments, they
 should be motivated and compliant to the protocol. They are encouraged to report to the PI
 should there be any problems occurred regarding the splints or any adverse effects developed
 in both treatment groups. Appropriate actions will be taken or advices given by the PI. The
 subjects in the splinting group are instructed to mark each night that they have worn the
 splints on a calendar. Subjects who missed the scheduled follow-up will be contacted and
 encouraged to attend the re-scheduled follow-up as soon as possible.

 Based on previous studies, the minimum clinically important difference is 0.74 for the BCTQ.
 With 90% statistical power, 5% significance level, and two-sided statistical tests, and
 assuming a standard deviation of 0.8 for the BCTQ score the study can detect a true
 difference of at least 0.74 point on the BCTQ between the two intervention groups when 50
 patients are randomized. Version 20.0 of the SPSS statistical package is used. Descriptive
 statistics are presented as frequencies, means with standard deviation or medians with ranges
 as appropriate. Baseline parameters of patient between two treatment groups are compared by
 chi-square test for categorical variables, Student's t test for continuous variables with
 normal distribution or Mann-Whitney U test for nonparametric continuous variables. BCTQ
 scores before treatment and at the one, four and twelve weeks after treatment are compared
 with paired samples t test. Differences of the BCTQ scores between the two treatment groups
 were investigated with independent samples t test. For multi-variate analysis, multiple
 linear regression is used to compute the differences of outcome measures between the two
 treatment groups, and within the groups before and after the respective treatments with
 adjustment for baseline variables. Results are considered statistically significant if the P
 value is less than 0.05.

 This trial has been approved by the local ethics committee (Kowloon West Cluster Ethical
 Committee). The trial will be conducted in full compliance with the Helsinki Declaration and
 the Guideline for Good Clinical Practice of the International Conference on Harmonisation of
 Technical Requirements for Registration of Pharmaceuticals for Human Use.
Inclusion Criteria:

 -  patients attending the medical clinic of Kwong Wah Hospital with clinical and
 electrophysiological features of CTS

 Exclusion Criteria:

 -  any recognized causes of CTS including inflammatory arthritis, diabetes mellitus,
 hypothyroidism, renal failure, polyneuropathy and history of significant local trauma

 -  previous treatment of CTS

 -  pregnancy

 -  patients with motor impairment or thenar muscle atrophy