Treatment for ulnar neuropathy at the elbow
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
The objectives of this systematic review are to determine the effectiveness and safety of conservative and surgical treatment in UNE. We intend to test the following hypotheses:
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Whether surgical treatment is effective in reducing symptoms and increasing nerve function;
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Whether conservative treatment is effective in reducing symptoms and increasing nerve function;
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Whether it is possible to identify the best treatment on the basis of clinical neurophysiological or nerve imaging.
Background
Ulnar neuropathy at the elbow (UNE) is the second commonest entrapment neuropathy after carpal tunnel syndrome, its mean annual crude incidence is 24.7 cases per 100,000 person‐years (Mondelli 2005). The clinical picture is typically characterised by nocturnal paresthesias involving the 4th and 5th finger, pain at the elbow, and sensory symptoms related with prolonged flexion of the elbow and in severe cases motor deficit of the hand ulnar innervated muscles (Dellon 1989). Diagnosis is based on signs, symptoms, clinical tests and electrodiagnostic studies. Now imaging, particularly ultrasound (Beekman 2004) and MRI (Bordalo 2004), is gaining more attention as a sensitive diagnostic tool. The Tinel sign (light percussion over the nerve at elbow) and the elbow flexion test are both useful tests for diagnosing cubital tunnel syndrome (Gelberman 1998), electrodiagnostic examination is necessary to confirm the diagnosis, to quantify the severity and to identify the exact site of ulnar nerve compression (AAEM 1999; Padua 2001). The treatment of UNE may be conservative (splint device, physical therapy, rehabilitation) or surgical (Bartels 2005a; Bartels 2005b; Biggs 2006). The goal of conservative treatment is to eliminate (Dellon 1993) or reduce the frequency of external compression on the nerve. Regarding surgical therapy, many procedures are employed for the treatment of cubital tunnel syndrome, including simple decompression, anterior transposition (subcutaneous, submuscular and intramuscular), and medial epicondylectomy (Eaton 1980; Kleinman 1989; Kuschner 1996; Tsai 1999). The basis for choosing a surgical technique must relate to the pathophysiology of the compression of the ulnar nerve at the elbow, an understanding of the aetiology of the ulnar nerve compression in the patient's particular case, and the potential drawbacks of the various operative procedures. Despite different opportunities in treating UNE, optimal management remains controversial.
Objectives
The objectives of this systematic review are to determine the effectiveness and safety of conservative and surgical treatment in UNE. We intend to test the following hypotheses:
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Whether surgical treatment is effective in reducing symptoms and increasing nerve function;
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Whether conservative treatment is effective in reducing symptoms and increasing nerve function;
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Whether it is possible to identify the best treatment on the basis of clinical neurophysiological or nerve imaging.
Methods
Criteria for considering studies for this review
Types of studies
The review will include controlled clinical trials using truly random or quasi‐random allocation of treatment. Prospective consecutive series of more than 10 patients where outcomes were collected by an observer other than the operating surgeon will be considered in the discussion. We will not consider single case reports.
Types of participants
People with clinical symptoms suggesting the presence of UNE with or without neurophysiological evidence of entrapment.
Types of interventions
Trials evaluating all forms of surgical and conservative treatments will be included in the review. Studies regarding therapy of UNE with or without neurophysiological evidence of entrapment.
Types of outcome measures
Primary outcomes
The primary outcome measure is defined as clinically relevant improvement in function compared to baseline. Function will be assessed with whatever scale was used by the authors with a preference for validated scales such as the Levine questionnaire for Carpal Tunnel Syndrome (Levine 1993), Disability of the Arm, Shoulder and Hand questionnaire (Hudak 1996), UNE questionnaire (Mondelli 2006). When self‐administered scales are used, we will evaluate if statistically significant changes are reported regarding the main scores of the questionnaires. The primary outcome measure will be dichotomised into improvement or no improvement, regardless of the differences between the tools used. If a study evaluates more than one functional outcome measure, a better score on at least one of the functional outcome measures will be enough to be considered as an improvement.
Secondary outcomes
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Change in neurological impairment measured by: (a) The strength of ulnar nerve innervated muscles with the MRC Sum Scale (BMRC 1976) (b) The presence and extent of sensory deficit measured with whatever instrument was used by the authors, but with a preference for cotton wool or Semmes‐Weinstein filaments (Bell‐Krotoski 1987).
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Change from the baseline of the motor nerve conduction velocity across the elbow.
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Change from baseline in the nerve diameter at the elbow evaluated by ultrasound or MRI.
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Change in quality of life.
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Adverse events.
Primary and secondary outcomes will be evaluated at a short follow‐up (one to six months) and at a long follow‐up (more than six months up to two years).
Search methods for identification of studies
Electronic searches
We will search the Cochrane Neuromuscular Disease Group Trials Register for randomised trials using ("cubital tunnel syndrome" OR "ulnar neuropathies"). In addition, we will adapt this stategy to search the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2007), MEDLINE (1950 to present), EMBASE (1980 to present), CINAHL (1982 to present), Allied and Complementary Medicine AMED (1985 to present), LILACS (1982 to present) and the Physiotherapy Evidence Database (PEDro). The search strategies are displayed in Appendix 1; Appendix 2; Appendix 3; Appendix 4 and Appendix 5.
Searching other resources
We will also search the references of relevant trials identified by the strategy. Where possible, we will contact authors of identified papers to determine whether other published or unpublished trials are available.
Data collection and analysis
Selection of studies
Two authors will independently review titles and abstracts of references retrieved from the searches and will select all potentially relevant studies. We will compare the results of our literature search to the review articles found using the previously mentioned databases. Furthermore, when data from one paper are re‐published by the same author in a larger investigation or written in English, only the most recent article will be considered. Copies of these articles will be obtained, and reviewed independently by the same authors against the inclusion criteria of the study. The authors will then extract data from included trials and assess trial quality independently with a specifically designed data extraction form.
Data extraction and management
The following data will be extracted:
(1) Study methods
(a) Design (e.g. randomised or quasi‐randomised, cohort study, case‐control study)
(b) Randomisation method (including list generation)
(c) Method of allocation concealment
(d) Blinding method
(e) Stratification factors
(2) Participants
(a) Inclusion/exclusion criteria
(b) Number (total/per group)
(c) Age distribution
(d) Associated morbidities
(e) Treatments
(f) Pre‐treatment quality of life and functional status, as measured by validated scales
(3) Intervention and control
(a) Type of therapy
(b) Type of control
(d) Details of control treatment including duration of non‐operative treatment
(4) Follow‐up data
(a) Duration of follow‐up
(b) Loss to follow‐up
(5) Outcome data
(a) BMRC scale
(b) Presence of sensory deficits (evaluated with cotton wool or Semmes‐Weinstein filaments)
(c) Self‐administered scales including questionnaires assessing regional function and symptoms (as Levine questionnaire for Carpal Tunnel Syndrome, Disability of the Arm, Shoulder and Hand questionnaire, UNE questionnaire, Visual Analogue Scale (VAS) (Sriwatanakul 1983) and quality of life measures (as SF‐36) (Ware 1992).
(d) Neurophysiology
(e) Ultrasound
(f) MRI
BMRC scale, presence of sensory deficits and regional self‐administered questionnaire will be considered the main outcome measures.
(6) Analysis data
(a) Methods of analysis (intention‐to‐treat/per‐protocol analysis)
(b) Comparability of groups at baseline (age, gender, clinical impairment, neurophysiological impairment, associated diseases)
(c) Statistical techniques
Data will be double entered into Review Manager (RevMan) independently by the first and second author.
Assessment of risk of bias in included studies
We will evaluate the validity of the trials by the following criteria:
(1) Selection bias
(a) Was allocation of patients to treatment and control groups randomised?
(b) Was randomisation concealed?
(2) Performance bias
(a) Were patients in the comparison groups treated differently apart from the study treatments?
(3) Attrition bias
(a) Were there systematic differences between the comparison groups in the loss of participants from the study?
(b) Were analyses by intention‐to‐treat?
(4) Detection bias
(a) Were those assessing outcomes of the intervention blinded to the assigned intervention?
We will summarise the quality of a trial into one of the three categories:
A. Adequate: there is a low risk of bias, since almost all (more than 75%) the validity criteria are met.
B. Unclear: there is a moderate risk of bias, since more than 25% validity criteria are not met.
C. Inadequate: there is a high risk of bias, since most criteria are not met.
Measures of treatment effect
Relative risk (RR) estimations with 95% confidence intervals (CI) will be used for binary outcomes.
Weighted mean difference estimations with 95% CI will be used for continuous outcomes. All analyses will include all participants in the treatment groups to which they were allocated.
If we collect data from case‐control studies, odds ratios (OR) and 95% CI will be considered.
Dealing with missing data
In the first instance, authors will be contacted to supply data missing from included studies. Missing data and drop‐outs or attrition will be assessed for each included study, and the extent to which the results or conclusions of the review could be altered by the missing data will be assessed and discussed. If less than 70% of participants allocated to the treatments are not reported on at the end of the trial, for a particular outcome, those data will not be used as they will be considered to be too prone to bias.
Assessment of heterogeneity
Clinical heterogeneity will be assessed by comparing the distribution of important participant factors between trials (age, gender, clinical impairment, neurophysiological impairment, associated diseases), and trial factors (randomisation concealment, blinding of outcome assessment, losses to follow‐up, treatment type, co‐interventions). Statistical heterogeneity will be assessed by examining I2, a quantity which describes approximately the proportion of variation in point estimates that is due to heterogeneity rather than sampling error. In addition, a chi squared test of homogeneity will be employed to determine the strength of evidence that heterogeneity is genuine.
Assessment of reporting biases
In order to detect potential publication bias, RRs and 95% CIs will be plotted against standard errors in each study (Funnel plots). Asymmetry can be due to publication bias, but can also be due to a relationship between trial size and effect size. In the event that a relationship is found, clinical diversity of the studies will be examined (Egger 1997).
Data synthesis
Where the interventions are the same or similar enough, we will carry out a meta‐analysis (DerSimonian 1986). Statistical analysis will be undertaken using the RevMan 4.2 program. We plan to synthesize results in a meta‐analysis.
Subgroup analysis and investigation of heterogeneity
We will conduct sub‐group analyses for:
(1) Two age groups: (≤ 45 yrs old, > 45 yrs old).
(2) Two clinical groups:
(a) Participants with only pathological motor conduction velocity across the elbow and no other neurophysiological abnormality.
(b) Participants with concomitant pathological motor conduction velocity across the elbow and one of the following criteria: i) denervation signs in the ulnar innervated muscle of the hand; ii) reduction of amplitude of sensory response in the 5th digit‐wrist segment.
Sensitivity analysis
Sensitivity analyses will be conducted to assess the impact of study quality. These will include analyses of randomised and quasi‐randomised controlled trials separately.
Adverse events
Since adverse events are rarely adequately dealt with by randomised studies alone because the numbers are small and follow‐up too short, adverse events (infections, worsening of symptoms) will be discussed taking into account the non‐randomised literature.
Cost‐benefit Analyses
Cost‐effectiveness of interventions will be considered where relevant data is available in the discussion.
