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Year : 2015  |  Volume : 52  |  Issue : 3  |  Page : 183-187

Carpal tunnel syndrome among other referral diagnoses in the Egyptian Clinical Neurophysiology Unit

Clinical Neurophysiology Unit, Cairo University, Cairo, Egypt

Date of Submission28-Mar-2015
Date of Acceptance25-Apr-2015
Date of Web Publication13-Aug-2015

Correspondence Address:
Ann A Abdel Kader
Professor & Head of Clinical Neurophysiology Unit, Cairo University, Kasr Aini Hospital, International Child Neurology Association Member (ICNA), Board of African Child Neurology Association (ACNA), 4 Mohamed Mazloum Street, Downtown, Cairo, 11513
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1110-1083.162035

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Nerve conduction (NC) studies and electromyography (EMG) are invaluable tools in the diagnosis of neuromuscular disorders. Databases with plenty of observations are useful in better assessment and safe and effective decision making.
The aim of this study was to analyze data provided by the EMG and NC records and to correlate referral diagnoses, especially carpal tunnel syndrome, with the final electrodiagnostic ones. This will offer strategic clues to minimize time, cost, and human errors.
The study was carried out in the Clinical Neurophysiology Unit, Faculty of Medicine, Cairo University. Tabulation of EMG/NC details for the cases examined during the study period (first half of the year 2014), followed by extensive analysis of the data provided, was carried out.
Most of the referral clinical diagnoses were of carpal tunnel syndrome (44%) and the least were of ulnar entrapment (1.3%). Concordance between referrals and final diagnoses was found only in 59.2% of patients. The most concordant referral was facial palsy and the most nonconcordant referral diagnosis was anal dysfunction.
Because of the occurrence of the referral diagnoses and the percentage of concordance between provisional and electrodiagnostic diagnoses, the unit is launching a local project for standardized guidelines for every provisional diagnosis.

Keywords: carpal tunnel, carpal tunnel syndrome guidelines, electromyography, final diagnosis, nerve conduction, referral diagnoses

How to cite this article:
Abdel Kader AA, Basheer MA, Maher EA, Elkholy SH. Carpal tunnel syndrome among other referral diagnoses in the Egyptian Clinical Neurophysiology Unit. Egypt J Neurol Psychiatry Neurosurg 2015;52:183-7

How to cite this URL:
Abdel Kader AA, Basheer MA, Maher EA, Elkholy SH. Carpal tunnel syndrome among other referral diagnoses in the Egyptian Clinical Neurophysiology Unit. Egypt J Neurol Psychiatry Neurosurg [serial online] 2015 [cited 2023 Oct 1];52:183-7. Available from: http://www.ejnpn.eg.net/text.asp?2015/52/3/183/162035

  Introduction Top

Nerve conduction studies (NCS) and electromyography (EMG) are invaluable electrodiagnostic (EDX) tools in the diagnosis of neuromuscular disorders. Unfortunately, both procedures involve subjecting the patient to physical discomfort, including electric shocks and needle punctures. Previously identified predictors of testing-related pain influenced patients' aversion for one test or the other. These included the absolute number of nerves and muscles tested, the inclusion of specific nerves or muscles in the test, as well as the referral and/or confirmed diagnosis (e.g. neuropathy) [1].

According to Berger and colleagues, 'Routinely collected and electronically stored information on healthcare utilization in everyday clinical practice has proliferated over the past several decades. Large computerized databases with millions of observations on the use of drugs, biologics, devices, and procedures along with health outcomes may be useful in assessing which treatments are most effective and safe in routine care without long delays' [2]. Applying this statement to electrodiagnosis suggests the usefulness of databases in assessing which testing procedure is most effective and safe in routine sessions without long examinations.

As being the only specialized Clinical Neurophysiology Unit in Egypt since 1987 in one of the oldest and largest university hospitals in the Middle East (http://neurology.kasralainy.edu.eg/), we consider ourselves as a site of reference. Analysis of the referrals of our patients and comparison with the final diagnosis reached, as well as identification of the most required muscles and nerves for testing, could serve to improve our teaching programs. This will help us to put our own touches to our working guideline for different cases. Because of its provisional abundance as referral diagnosis, we chose to start by the unit's guidelines to EDX protocol of carpal tunnel syndrome (CTS).

  Aim of work Top

The aim of this study was to analyze data provided by the EMG and nerve conduction records carried out during 1-month duration and correlate referral diagnoses, especially CTS, with the final EDX ones to offer clues about the concordance between referrals and final diagnoses, in an attempt to minimize time, cost, and human errors.

  Patients and methods Top

This prospective study was carried out in the Clinical Neurophysiology Unit, Cairo University. An analysis was carried out on the flow of patients into our unit during the first 6 months of year 2014. The number of patients and the tests requested for them were noted. Moreover, sites of referral (whether inpatients or outpatients) were analyzed, which is of immense help, together with the detailed records, in providing better quality of services.

As a sample to fulfill the study aim, the records of patients who attended the clinic during March 2014 were included in the extensive analysis part of the study. We tabulated the following data for each examined patient: the referral diagnoses of the clinicians, examined muscles during EMG session, examined nerves (sensory and/or motor), and the final electrophysiologic diagnosis.

Diagnoses were classified into 11 items as follows: CTS, ulnar entrapment, facial palsy, nerve injury, peripheral neuropathy (PN), radiculopathy (RD), motor neuron disease, neuromuscular junction disorders, myopathy, brachial plexopathy, anal dysfunction, or 'others'. The item 'others' referred to other diagnoses not mentioned above, or any vague referrals such as weakness, numbness, and tingling.

The nerves were classified on the basis of the results into three groups as follows: normal, evidence of axonal affection, or evidence of demyelination. Finally, the muscles examined were also classified on the basis of the results as follows: normal, neurogenic, or myopathic motor unit potentials (MUPs).

The data were coded and entered using the statistical package SPSS, version 15 (SPSS Inc., Chicago, Illinois, USA). The data were summarized using descriptive statistics: minimal, maximum, mean and percentage values for quantitative variables, and number.

  Results Top

The number of EDX tests carried out at the unit during the first 6 months of 2014 was 2477 tests, distributed per month as shown in [Table 1].
Table 1: Number of patients attending the Clinical Neurophysiology Unit, Kasr Al-Ainy, Cairo University from January to June 2014

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The average number of patients per day undergoing EMG, NCS (visual-evoked potential studies or flash electroretinorgaphy) and electroencephalography tests was 8:5:3.

Detailed analysis of March 2014 EMG and NC records showed the following: the preliminary sample size - recorded at the front desk - was 235 records, whereas the number of cases tabulated by residents was 230, 129 female and 101 male patients, with five missed cases. The percentage of successful medical recording was 97.9%.

The maximum number of examined muscles per patient was eight and the minimum was one, with an average of 1.7 (exclusive NCS were not included). The biceps brachii and the first dorsal interosseus muscles were the most examined muscles in the upper limb (10.13 and 7.8%, respectively), whereas the most commonly examined muscles in the lower limb were the tibialis anterior and vastus medialis muscles (14.75 and 12.4%, respectively). The most commonly examined axial muscle was the orbicularis oris muscle (five times, 2.3%). The least commonly examined muscles in the upper limbs were the flexor pollicis longus and flexor digitorum sublimis (once each). The iliopsoas, the adductor halluces, and the dorsal and lumbosacral paraspinal muscles were not examined at all.

Muscles were reported as being normal in 99 out of the 217 needle pricks (45.62%). The first dorsal interosseus and biceps brachii muscles had the highest normalcy rates (58.8 and 54.54%, respectively), followed by the deltoid and the gastrocnemius muscle (50% each). The affected muscles on examination were 118/217 (54.38%). The orbicularis oculi had the highest abnormality rate (4/4, 100%), followed by the orbicularis oris and the extensor digitorum brevis muscle (4/5; 80% each), followed by the extensor indices (4/6; 33.3%). The more common pattern of affection was neurogenic affection (neurogenic/myogenic; 89/29).

The total number of examined motor nerves was 285 nerves. The maximum number of examined nerves in motor conduction studies per patient was four nerves, whereas the minimum was one, with an average of 1.2. The most commonly examined nerve was the median nerve (38.95%), followed by the ulnar (18.2%) and then the peroneal nerve (15.79%). The axillary, musculoskeletal, and femoral nerves were not examined for any patient. Motor nerves were diagnosed as normal in 179/285 (62.81%). The ulnar nerve had the highest normalcy rate (52/71; 73.2%), followed by the tibial nerve (27/42, 64.3%). The number of affected nerves was 106/285 (37.19%). Although the facial nerve was examined only five times, it showed the highest rate of abnormalities (4/5, 80%), followed by the radial nerve (6/9, 66.7%). The more common pattern of affection was the axonal pattern (axonal/demyelination; 71/35).

The total number of examined sensory nerves was 257 nerves. The maximum number of examined nerves in sensory conduction studies per patient was three, whereas the minimum was one, with an average of 1.1. The ratio of upper to lower limb nerves examined was 8:5. The most commonly examined nerve was the median nerve (44.36%), whereas the least commonly examined nerve was the medial plantar nerve (3/257; 3.11%). The total number of normal sensory nerves was 167/257 (64.98%). The superficial peroneal nerve had the highest normalcy rate (6/6, 100%), followed by the ulnar nerve (86/104; 82.7%). The total number of affected sensory nerves was 90/257 (35.02%). The median nerve (59/114, 51.75%) and the sural nerve (7/16, 43.75%) had the highest rate of abnormality. The more common pattern of affection was the demyelinating pattern (demyelination/axonal; 51/35). The sensory response was absent in two cases.

Most of the referral clinical diagnoses were of CTS (100 cases, 44%). 'Others' represented the second common referral (12.2%), whereas ulnar entrapment, brachial plexopathy, and anal dysfunction (three cases each, 1.3%) were the least common referrals.

There were 25 cases of nerve injuries: six radial, five median, four ulnar, and one sciatic. Four of them were reported to have normal EMG and NCS. Upper limb injuries were 15-times more frequent compared with lower limb injuries; the radial nerve was the most frequently injured nerve.

There were 20 cases of PN as referral diagnosis in which the ulnar nerve (motor and sensory) and the peroneal (motor only) were mostly affected (50% of cases). The median and tibial nerves were affected only in 10% of cases.

Myopathic motor units were recorded in eight cases, most frequently from the deltoid biceps in the upper limbs (30% of cases) and the vastus medialis in the lower limbs (30% of cases). The triceps and gastrocnemius were least affected (10%).

Repetitive 3 Hz supramaximal stimulation showed positive decremental response in 7/9 (77.8%) cases referred with neuromuscular junction disorder as a provisional diagnosis.

Four patients provisionally diagnosed with motor neuron disease (4/9, 44.4%) showed the typical pictures of an active ongoing denervation, together with chronic neurogenic MUPs in three regions (upper limb, lower limb, and cranial). Of 28 'others' referral diagnosis, 12 had normal final diagnosis and six had CTS.

Concordance between referrals and final diagnoses was found in 59.2% of cases. The most concordant (100%) referral diagnosis was facial palsy and the most nonconcordant referral diagnosis was anal dysfunction. Of the 94 nonconcordant cases, 69 patients had 'no abnormalities' [Table 2].
Table 2: Concordance between final diagnoses and referral diagnoses

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  Discussion Top

When data are inaccessible, such as when on paper or in systems that cannot be mined for information, its value drops to zero. Data management brings life to data and thus enables us to unlock the value of what we hold. In this study, EDX data held in low accessibility sources were transformed to data stores that can be analyzed in correlation with clinical data. This helps us to optimize the examination procedure and time and consequently figure out how to maximize the number of patients per day. Limited working hours, educational activities held in our laboratory, and the multiple referring sources results in a long waiting list, which is usually disabling to the patients and postpones their treatment, thus extending their suffering. Moreover, patients may seek other places for earlier examination dates, other than home facility, which will result in dropouts.

An analysis on the number of patients attending our laboratory shows that there is a steady flow of EMG/NCS examinations. As expected, provisionally, the diagnosis of CTS had a percentage of 44% from all total referrals. Such non minor percentage, of having carpal tunnel as a referral diagnosis, strongly invited the unit to offer guidelines and recommendations for CTS examination [3],[4] [Table 3] such that junior staff, with the most working hours demanded, may be able to perfectly examine them alone with no senior supervision unless of course the case was not straightforward. All unit members were consulted before its approval. This will help so much in extending the outcome of our working hours. The CTS guideline was just a start and we recommend that according to frequency of referrals other guidelines should be agreed upon soon.
Table 3: CTS guidelines at CNPU, Kasr Al-Aini, Cairo University

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No abnormalities were detected in 30% of cases provisionally diagnosed with CTS. Moreover, in CTS patients, NCS might be normal even in proper clinical data, which might add to the conflict of evaluation. Knowing that comparative NCS techniques are routinely performed in our laboratory to suspected CTS patients, and that these techniques increase the sensitivity of detecting CTS up to 98% [5], we can deduce that clinicians overdiagnose CTS. This should not be underestimated, as the patients spend unnecessary time and money, as well as some discomfort, during NCS examination.

Surprisingly, the second most common group of provisional diagnoses was 'others'. On analyzing those referrals, we found that, they are mostly symptoms and not diagnoses, such as lower or upper limb weakness, numbness, and brachialgia. This requires too much time, as we have to comprehensively, instead of concisely, examine the patient before electrodiagnosis. Sometimes we ask to recontact the referring physician to clarify his provisional diagnosis. This raises a question about the clarity of EDX examination and its limitations among referring sources.

For PN cases, launching the NC session with the most likely affected nerves - the ulnar and peroneal - will minimize the patient's discomfort and allows collection of important and relevant data early before the potential patient's decision of not continuing the session. As regards muscle diseases, launching the EMG session with the most likely affected muscles - the biceps and vastus medialis - will be more successful, thus allowing us to promptly detect EMG abnormalities.

Patients referred with a provisional diagnosis of RD showed a high percentage of no abnormality. Combining EMG with imaging techniques is necessary before excluding RD [6].

In facial palsy (lower motor type), sensitivity of orbicularis oris and occuli were the same in detecting neurogenic MUPs; thus, unless evaluation of specific branches is requested, it would be enough to examine either of them.

Our final electrophysiological diagnosis was correlated with the provisional clinical diagnosis. In 11% of cases, EDX studies revealed a different diagnosis than that referred. The triad of CTS, PN, and RD showed the highest missreferrals such as PN or RD turn out to be just CTS or vice versa. This should always be taken into consideration by the clinical neurophysiologists. They must not dismiss the patients with tingling or numbness until they exclude (or prove) the existence of any of those three above-mentioned conditions. In 30% of cases, no detectable abnormality was found, which might redirect the referring physician to other investigations. Finally, 59% of the provisional diagnoses were confirmed.


Continuous implementation of this study methodology for every modality in the unit, as well as sharing the study outcome with all the referring physicians, is recommended.


The authors thank Aya Salah, Sara Diab and Yousra Abdallah for their effort spent in fulfilling the master table.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Jerath NU, Strader SB, Reddy CG, Swenson A, Kimura J, Aul E. Factors influencing aversion to specific electrodiagnostic studies. Brain Behav 2014; 4 :698-702.  Back to cited text no. 1
Berger ML, Mamdani M, Atkins D, Johnson ML. Good research practices for comparative effectiveness research: defining, reporting and interpreting nonrandomized studies of treatment effects using secondary data sources: the ISPOR Good Research Practices for Retrospective Database Analysis Task Force Report - part I. Value Health 2009; 12 :1044-1052.  Back to cited text no. 2
Gazioglu S, Boz C, Cakmak VA. Electrodiagnosis of carpal tunnel syndrome in patients with diabetic polyneuropathy. Clin Neurophysiol 2011; 122 :1463-1469.  Back to cited text no. 3
Werner RA, Andary M. Electrodiagnostic evaluation of carpal tunnel syndrome. Muscle Nerve 2011; 44 :597-607.  Back to cited text no. 4
Lee WJ, Liao YC, Wei SJ, Tsai CW, Chang MH. How to make electrodiagnosis of carpal tunnel syndrome with normal distal conductions? J Clin Neurophysiol 2011; 28 :45-50.  Back to cited text no. 5
Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations (Expert Consult-Online) 2012. United Kingdom: Elsevier Health Sciences.  Back to cited text no. 6


  [Table 1], [Table 2], [Table 3]

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