Abstract
Background
Electrodiagnostic tests (EDx) can determine when symptoms and signs suggestive of idiopathic ulnar neuropathy at the elbow (cubital tunnel syndrome; CubTS) is due to measurable ulnar neuropathy at the elbow (UNE), cervical radiculopathy, or median neuropathy at the carpal tunnel, and when there is no measurable neuropathology associated with the symptoms. The role of EDx in management of CubTS is debated.
Questions
(1) What is the percentage of patients with CubTS (both including and excluding patients with a previous electrodiagnosis of idiopathic UNE) that have EDx results consistent with idiopathic UNE, other neuropathology, and no detectable neuropathology (2) What factors (e.g. age and gender); are independently associated with electrodiagnosis of UNE.
Methods
We retrospectively reviewed all medical records of 133 patients with a working diagnosis of CubTS sent for EDx over a 5-year period in one large urban medical center. We recorded data on patient demographics, comorbidities, non-specialist or specialist referring physician, and EDx results.
Results
Among 133 patients, 61% (N = 81) of EDx identified idiopathic UNE, 14% (N = 18) identified other neuropathology, and for 26% (N = 34) there was no measurable neuropathology. Among the 14 patients with a previous ipsilateral or contralateral electrodiagnosis of UNE, all 14 had electrodiagnosis of UNE. Older age and men were independently associated with an increased likelihood of UNE.
Conclusions
The observation that people diagnosed with CubTS often do not have UNE, particularly if they are relatively young, suggests that the diagnosis of CubTS may benefit from a more stringent clinical prediction rule.
Level of Evidence
Diagnostic; Retrospective cohort study; Level III.
Keywords: Cubital tunnel syndrome, Ulnar neuropathy, Electrodiagnosis, Elbow
1. Introduction
It is important to distinguish symptoms and signs suggestive of a pathophysiology and objectively verifiable pathophysiology. For instance, the diagnosis of cubital tunnel syndrome (CubTS) may not always correspond with idiopathic ulnar neuropathy at the elbow/cubital tunnel (UNE). UNE is the second most common peripheral mononeuropathy of the upper extremity after idiopathic median neuropathy at the carpal tunnel (MNCT).1, 2, 3, 4 The symptoms and signs suggestive of UNE (paresthesia in the small and ring finger, worse with sustained elbow flexion or pressure over the cubital tunnel, progressing to loss of sensibility, loss of dexterity, and weakness and atrophy of the first dorsal interosseous muscle) are referred to as cubital tunnel syndrome (CubTS). The estimated annual incidence of diagnosed CubTS is up to 1 in 3000.2,3,5 Given initial diagnosis of CubTS (at least with strict diagnostic criteria) tends to be associated with advanced UNE with weakness, loss of sensibility, and atrophy,1,6,7 it is possible that UNE is often undiagnosed and may be much more common.4,5 A population-based study of 1001 metropolitan United States residents identified a prevalence of CubTS between 1.8% (strict criteria) and 5.9% (inclusive criteria) using a survey of hand and upper extremity nerve compression symptoms and hand diagrams for numbness.8 In a study of 102 patients with end-stage renal disease receiving hemodialysis at one unit, 90 were eligible and were screened for signs and symptoms of CubTS.9 Among the 73 patients (81%) with at least 1 symptom or sign of CubTS, 37 (51%) had UNE on electrodiagnostic testing (EDx).9 What is not clear is the degree to which this very high prevalence of UNE is related to renal insufficiency (or perhaps diabetes) or if this is a manifestation of the relatively older age of these patients.
Similar to MNCT, to date, there is no consensus reference standard for the diagnosis of UNE. Some clinicians believe that UNE meriting operative treatment may not be detectable on EDx,10 while others consider this – at worst – very mild UNE and are concerned about potential misdiagnosis, and would not offer surgery.7
A study of patients referred for EDx with a working diagnosis of CubTS applied by both specialists and non-specialists in one medical center represents the spectrum of application of this diagnosis. The corresponding range of EDx test results can help determine when symptoms and signs suggestive of idiopathic UNE (CubTS) are due to measurable UNE, cervical radiculopathy, or MNCT, and when there is no measurable neuropathology to account for the symptoms. If there is a notable lack of correspondence between what clinicians guess is the cause of the symptoms and the electrophysiological evidence regarding what might be causing the symptoms, it would indicate a need for more stringent criteria for applying the diagnosis of CubTS. For instance, perhaps some people apply the diagnosis based on pain rather than paresthesia. Or perhaps provocative tests are not adequately accounted for. An understanding of the current percentages of accurate diagnosis, inaccurate diagnosis, and absence of measurable pathology might aid in more accurate diagnosis based on symptoms and signs (e.g. clinical prediction rules), more selective use of EDx, and more appropriate utilization of operative treatment. Identification of factors such as age, gender, and contralateral prior UNE independently associated with electrodiagnosis of UNE might further inform construction of a better clinical prediction rule.
2. Materials & methods
2.1. Study design
This retrospective study was approved by our institutional review board. The only inclusion criterion was referral to the EDx testing center with a working diagnosis of CubTS. We excluded patients who were pregnant at the time of the EDx, had a known injury of the ulnar nerve of the affected arm, had polyneuropathy, or who previously underwent ipsilateral cubital tunnel release (CubTR). All electronic medical records of patients who underwent EDx tests over a 5-year period were manually reviewed – by research assistants not involved in patient care – to establish whether the patient fulfilled the predefined eligibility criteria. After application of inclusion and exclusion criteria, we had a consecutive series of 180 eligible patients with a working diagnosis of CubTS who were sent to an EDx unit in an academic institution in a large urban area to confirm or rule out UNE.
2.2. Outcome measures
The following data was derived from medical records at the time point prior to EDx: age, sex, symptomatic side, diagnosis of UNE or MNCT on previous EDx (Table 1, Table 2), diabetes mellitus, thyroid disease, and chronic inflammatory disease like ulcerative colitis or Crohn's disease (Appendices A and B). Previous electrodiagnosis of UNE or MNCT was divided into the following categories: (1) no (not done or not electrodiagnostically confirmed); (2) ipsilateral; (3) contralateral to the symptomatic side; and (4) bilateral. Thyroid disease was divided into: (1) hypothyroidism; and (2) hyperthyroidism. We recorded if the referring physician was a specialist that treats CubTS (an orthopaedic surgeon, a plastic surgeon, a neurosurgeon, or a neurologist) or not (other specialty or non-specialist). Initial treatment given by the referring physician after EDx was also assessed and divided into: (1) unknown; (2) nonoperative; and (3) operative (Appendices A and B).
Table 1.
Patient and clinical characteristics per diagnostic group for the total cohort.
| Variables | Total cohort N = 133 |
|||
|---|---|---|---|---|
| No UNE N = 34 (26) | UNE N = 81 (61) | P value | Other neuropathology N = 18 (14) | |
| Age in years | 43 ± 13 (17–74) | 53 ± 13 (16–83) | <0.001 | 57 ± 12 (40–86) |
| Sex | ||||
| Women | 21 (62) | 30 (37) | 0.02 | 9 (50) |
| Men | 13 (38) | 51 (63) | 9 (50) | |
| Symptomatic side | ||||
| Unilateral | 28 (82) | 69 (85) | 0.78 | 12 (67) |
| Bilateral | 6 (18) | 12 (15) | 6 (33) | |
| Previous UNEa | ||||
| No | 33 (100) | 66 (83) | 0.10 | 18 (100) |
| Ipsilateral | 0 (0) | 3 (3.8) | 0 (0) | |
| Contralateral | 0 (0) | 7 (8.8) | 0 (0) | |
| Bilateral | 0 (0) | 4 (5.0) | 0 (0) | |
| Previous MNCTa | ||||
| No | 32 (97) | 73 (91) | 0.87 | 16 (89) |
| Ipsilateral | 1 (3.0) | 3 (3.8) | 2 (11) | |
| Contralateral | 0 (0) | 1 (1.3) | 0 (0) | |
| Bilateral | 0 (0) | 3 (3.8) | 0 (0) | |
Bold indicates statistically significant difference; Continuous variables as mean ± standard deviation (range); Discrete variables as number (percentage); UNE: Ulnar neuropathy at the elbow; MNCT: median neuropathy at the carpal tunnel; aData for 1 patient missing for the “No UNE” and the “UNE” groups.
Table 2.
Patient and clinical characteristics per diagnostic group looking at the cohorts with and without a previous UNE diagnosis.
| Variables | Without previous UNE N = 117 |
With previous UNE N = 14 |
|||||
|---|---|---|---|---|---|---|---|
| No UNE N = 33 (28) | UNE N = 66 (56) | P value | Other neuropathology N = 18 (15) | No UNE N = 0 | UNE N = 14 (100) | Other neuropathology N = 0 | |
| Age in years | 44 ± 13 (17–74) | 53 ± 13 (16–83) | 0.002 | 57 ± 12 (40–86) | – | 55 ± 14 (28–77) | – |
| Sex | |||||||
| Women | 20 (61) | 24 (36) | 0.03 | 9 (50) | 0 (0) | 5 (36) | 0 (0) |
| Men | 13 (39) | 42 (64) | 9 (50) | 0 (0) | 9 (64) | 0 (0) | |
| Symptomatic side | |||||||
| Unilateral | 27 (82) | 57 (86) | 0.56 | 12 (67) | 0 (0) | 11 (79) | 0 (0) |
| Bilateral | 6 (18) | 9 (14) | 6 (33) | 0 (0) | 3 (21) | 0 (0) | |
| Previous UNE | |||||||
| No | – | – | – | – | – | 0 (0) | – |
| Ipsilateral | – | – | – | – | 3 (21) | – | |
| Contralateral | – | – | – | – | 7 (50) | – | |
| Bilateral | – | – | – | – | 4 (29) | – | |
| Previous MNCT | |||||||
| No | 32 (97) | 64 (97) | 1.00 | 16 (89) | 0 (0) | 9 (64) | 0 (0) |
| Ipsilateral | 1 (3.0) | 1 (1.5) | 2 (11) | 0 (0) | 2 (14) | 0 (0) | |
| Contralateral | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (7.1) | 0 (0) | |
| Bilateral | 0 (0) | 1 (1.5) | 0 (0) | 0 (0) | 2 (14) | 0 (0) | |
Bold indicates statistically significant difference; Continuous variables as mean ± standard deviation (range); Discrete variables as number (percentage); UNE: Ulnar neuropathy at the elbow; MNCT: median neuropathy at the carpal tunnel.
The primary outcomes were electrodiagnosis of UNE, other neuropathology (e.g. MNCT, cervical radiculopathy, or brachial plexopathy), and no neuropathology.
2.3. Electrodiagnostic testing
In our hospital system, in line with AANEM guidelines,4,11 skin temperatures were monitored, the elbow was flexed between 70 and 90°, and the following electrodiagnostic criteria for UNE were used: (1) above elbow to below elbow (AE to BE) nerve conduction velocity (NCV) of <50 m/s (m/s); (2) AE to BE NCV of >10 m/s slower than BE to wrist NCV; (3) >20% decrease of compound motor action potential (CMAP) from BE to AE; and (4) change of CMAP waveforms between AE and BE. We then calculated the number of patients for all EDx criteria per diagnostic group (Table 3). According to AANEM guidelines, a diagnosis of UNE was made when at least two out of four criteria were met.4,11
Table 3.
Number of patients per electrodiagnostic criterion per diagnostic group.
| Variables | No UNE N = 34 | UNEa N = 79 | P value | Other neuropathology N = 18 | P value |
|---|---|---|---|---|---|
| AANEM #1: AE to BE NCV <50 m/s | |||||
| No | 32 (94) | 30 (38) | <0.001 | 12 (71) | <0.001 |
| Yes | 2 (5.9) | 49 (62) | 5 (29) | ||
| AANEM #2: AE to BE NCV >10 m/s slower than BE to wrist | |||||
| No | 31 (91) | 38 (48) | <0.001 | 17 (100) | <0.001 |
| Yes | 3 (8.8) | 41 (52) | 0 (0) | ||
| AANEM #3: BE to AE CMAP decrease waveforms >20% | |||||
| No | 33 (97) | 64 (81) | 0.04 | 16 (94) | 0.04 |
| Yes | 1 (2.9) | 15 (19) | 1 (5.9) | ||
| AANEM #4: Change of CMAP waveforms between AE to BE | Not assessed | ||||
Bold indicates statistically significant difference; Discrete variables as number (percentage); UNE: Ulnar neuropathy at the elbow; AANEM: American Association of Neuromuscular & Electrodiagnostic Medicine; AE: Above elbow; BE: Below elbow; NCV: Nerve conduction velocity; CMAP: Compound motor action potential; m/s: meter per second; aData for 2 patients missing.
2.4. Study population
Within our timeline, a total of 180 patients were referred to the EDx unit for assessment of possible UNE. Forty-seven (26%) tests were excluded (25 had an ipsilateral trauma or lesion of the ulnar nerve; 21 had an ipsilateral previous decompression or transposition of the ulnar nerve; and 1 had polyneuropathy), leaving 133 patients for analysis. Fifty-six percent were referred by a specialist and the remaining 44% were referrals from other physicians from within or out of the hospital health care system. Fourteen patients had previous electrodiagnosis of UNE including 3 ipsilateral, 7 contralateral, and 4 bilateral.
3. Calculation
The distributions of continuous variables and assumptions concerning normality were assessed using histogram plots and Shapiro–Wilk tests to determine the appropriateness of the statistical tests. Continuous variables are presented as mean ± standard deviation and discrete data as proportions. We used Pearson correlation tests for the relationships between continuous variables, one-way analysis of variance tests to assess mean differences between categorical variables, Student's t-tests to assess differences between continuous variables, and Fisher's exact tests for discrete variables.
For further analysis, only the diagnostic groups (1) with UNE and (2) without UNE were used, omitting the group with another neuropathology.
We created a multivariable logistic regression model to assess factors independently associated with electrodiagnostically confirmed UNE (Table 4). We included all variables with P < 0.10 on bivariate analysis in the final model (Table 1). An odds ratio demonstrates the odds of having electrodiagnosis of UNE in one group as compared with another (for categorical variables) or a per-unit increase for continuous variables. The C statistic is a measure of model fit and is the area under the receiver operating characteristics curve. We considered P < 0.05 significant.
Table 4.
Multivariable logistic regression analysis of factors associated with UNE.
| Retained variables | Odds ratio | 95% confidence interval | Standard error | P value | C statistica |
|---|---|---|---|---|---|
| Age in years | 1.1 | 1.0 to 1.1 | 0.02 | 0.003 | 0.72 |
| Men | 2.5 | 1.0 to 6.2 | 1.2 | 0.04 | |
| Previous UNEb | Omitted from model: perfect prediction | ||||
Bold indicates statistically significant difference; UNE: ulnar neuropathy at the elbow; aThe C statistic is a measure of model fit and is the area under the receiver operating characteristics curve; bEither ipsilateral, contralateral, bilateral.
We did not perform an a priori power analysis since we included all eligible patients in our given timeline.
4. Results
4.1. Electrodiagnosis of UNE, other neuropathology, and no neuropathology
For the entire cohort of patients referred for EDx with a working diagnosis if CubTS, 61% of EDx results (N = 81) were interpreted as UNE, 26% (N = 34) as no neuropathology, and 14% (N = 18) as another diagnosis (9 had MNCT; 6 had cervical radiculopathy; 2 had peripheral neuropathy; and 1 had brachial plexopathy; Table 1). Patients with UNE were, on average, 10 years older (53 vs. 43 years old) and more likely to be men (63% vs. 38%), compared with the non-UNE group (Table 1).
Among the 14 patients with a previous electrodiagnosis of UNE (21% [N = 3] ipsilateral, 50% (N = 7) contralateral, and 29% (N = 4) bilateral), all had electrodiagnosis of UNE (Table 2).
In the group without a previous UNE electrodiagnosis, 56% of EDx results (N = 66) were interpreted as UNE, 28% (N = 33) as normal, and 15% (N = 18) as another diagnosis (Table 2).
4.2. Factors associated with electrodiagnosis of UNE
Among the subgroup of people without a prior electrodiagnosis of UNE, older age (odds ratio [OR] 1.1; 95% confidence interval [CI] 1.0 to 1.1; P = 0.003) and men (OR 2.5; 95% CI 1.0 to 6.2; P = 0.04; C statistic full model = 0.72) were independently associated with an increased likelihood of electrodiagnosis of UNE (Table 4). Interpreting the model, a 1-year increase in age increases the chance of having an electrodiagnosis of UNE by 1.1 times and men were 2.5 times more likely to have UNE than women.
5. Discussion
Idiopathic UNE is the second most common peripheral mononeuropathy of the upper extremity.1, 2, 3, 4 We assessed discrepancies between the number of patients with a working diagnosis of CubTS sent for EDx and those with objectively verifiable pathophysiology (UNE). We found that 100% of patients with ipsilateral or contralateral UNE in the past had confirmed UNE, but among people with no prior diagnosis, just over half had UNE, nearly a third had normal tests, and 14% had another neuropathology and this was true for both specialists and non-specialists.
This study has some limitations. First, this is a retrospective study with no systematic collection of data on symptoms or examinations, and no protocol utilizing diagnostic scores, clinical prediction rules, or clinician pretest confidence in the diagnosis. For instance, we did not have data available for the presence of osteoarthritis or deformity of the elbow, which could aid in diagnosing CubTS and make clinicians more confident that EDx would be positive for UNE. On the other hand, we consider it a good representation of daily practice because it represents all the EDx performed at a large institution from multiple specialist and non-specialist referring physicians. The exact numbers might change in different settings, but the observation that a clinical diagnosis is often not supported by EDx results is unlikely to change. A more structured study would be able to better distinguish people sent for confirmation and people sent to exclude idiopathic UNE as a cause of the symptoms. Second, patients with suspected UNE that were sent for EDx in this large urban institution may not be representative of the population sent for testing in other areas, hospitals or practice settings, which might limit generalizability. Third, this sample represents all ordered tests by many different health care providers. However, 56% (N = 75) were referred by a specialist. The working diagnoses of CubTS, as currently made based on symptoms and signs, might be suboptimal for a substantial number of patients. We feel that this testing paradigm is representative of the typical paradigm in the United States. Finally – and maybe most importantly, there is no consensus reference standard for the diagnosis of UNE. The American Academy of Orthopaedic Surgeons has a clinical practice guideline for CTS, but not for CubTS.12 The American Association of Electrodiagnostic Medicine (AAEM) published practice guidelines with standards and recommendations for additional EDx studies for patients diagnosed with UNE in 19994,11 and many electrodiagnosticians use these standards.2,13, 14, 15, 16, 17 Based on a critical review of 13 out of 398 studies, the AANEM report sensitivities ranging from 37% to 86% and specificities of 95% or greater for the various nerve conduction measures, i.e. latencies and amplitudes.4 The lack of a reference standard for UNE and the broad range in sensitivities for EDx highlight room for improvement in electrodiagnosis of UNE. Therefore, the actual percentage of patients with UNE in this cohort might be higher or lower. Some may wonder about the absence of thoracic outlet syndrome. But thoracic outlet syndrome is variably diagnosed (in our hands it is rare and typically associated with other pathophysiology such as clavicle malunion, an anomalous rib, or subclavian vein thrombosis), typically diagnosed based on pain rather than paresthesia, and nearly always diagnosed in the absence of electrodiagnostic abnormality, which is a primary reason we do not find the diagnosis useful (not objectively verifiable and potentially socially constructed). No one in the cohort was diagnosed with thoracic outlet syndrome by the independent group of neurologists and physical medicine physicians that staff the electrodiagnostic lab, further supporting the relatively limited utility of the diagnosis in our opinion.
The observation that fewer than two out of three patients with a provisional diagnosis of CubTS received an electrodiagnosis of UNE and 14% had a different nerve problem (e.g. cervical radiculopathy) suggest the potential benefits of a more stringent set of symptoms and signs (clinical prediction rule) for CubTS. Another prior similar review of 283 patients found 58% had an electrodiagnosis of UNE, 35% had no measurable neuropathology, and 6.7% were uncertain.14 In a study of 350 worker compensation patients who had surgery for CubTS, 34% of EDx results were not consistent with AANEM guidelines, which raises the concern that overvaluing imprecise syndromes might increase the potential for unnecessary or unhelpful surgery.17
The finding that older age and men were more likely to develop UNE, is generally consistent with other studies2,3,5,6,14,16,17 and also supports the concept that this is an inherent, slowly progressive disease. The observation that UNE detected before did not resolve, combined with the fact that everyone tested who had known ulnar neuropathy on the other side had it on the newly tested contralateral side, is consistent with the concept that idiopathic mononeuropathy at the cubital tunnel is a structural, slowly progressive disease.
6. Conclusions
The high rate (39%) of patients with a working diagnosis of clinical CubTS that had no measurable neuropathology, with no difference between specialists and non-specialist referring physician, suggests a potential role for improved diagnostic criteria (clinical prediction rule). A test has better diagnostic performance characteristics when the pre-test likelihood of diagnosis is higher. Ordering a test because one is confused and uncertain often has more potential for harm than benefit. Therefore, ordering a test to confirm a likely diagnosis is preferred. If we can agree that mild UNE is best treated nonoperatively,13 then an improved clinical prediction rule with a higher probability of moderate to severe UNE could limit the role of EDx, and reduce the potential for unhelpful or unnecessary surgery. Said differently, there seems to be a need for comfort with less specific diagnoses in the absence of characteristic symptoms and signs. Applying a specific diagnosis such as CubTS might be associated with less appropriate and potentially harmful treatment strategies than a less specific diagnosis such as nonspecific arm pain or nonspecific paresthesia.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.
Ethical committee approval
This study received approval from the Institutional Review Board of the Massachusetts General Hospital using a continuing protocol for studies carried out using the Orthopaedic Hand Service Data Repository, Protocol # 2009P001019/MGH. This study has been performed in accordance with the ethical standards in the 1964 Declaration of Helsinki. This study has been carried out in accordance with relevant regulations of the US Health Insurance Portability and Accountability Act (HIPAA).
Statement of location
This study was performed at The Orthopaedic Hand and Upper Extremity Service of the Massachusetts General Hospital – Harvard Medical School and the Department of Surgery and Perioperative Care of the Dell Medical School – The University of Texas at Austin.
Author statement
Joost T.P. Kortlever, MD, Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Project administration; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; Writing - review & editing, Berdien Brandsema, MD, Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Project administration; Roles/Writing - original draft; Writing - review & editing, Gertraud Gradl-Dietsch, MD, Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Project administration; Roles/Writing - original draft; Writing - review & editing, Meijuan Zhao MD, Conceptualization; Investigation; Methodology; Project administration; Roles/Writing - original draft; Writing - review & editing, David Ring, MD, PhD, Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Project administration; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; Writing - review & editing.
Declaration of competing interest
No benefits in any form have been received or will be received related directly or indirectly to the subject of this article.
JK, BB, GGD, and MZ certify that they have no commercial associations (e.g. consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.
DR has or may receive payment or benefits from Skeletal Dynamics, Wright Medical for elbow implants, Deputy Editor for Clinical Orthopaedics and Related Research, Universities and Hospitals, Lawyers outside the submitted work.
Acknowledgments
None.
Contributor Information
Joost T.P. Kortlever, Email: kortlever.joost@gmail.com.
Berdien Brandsema, Email: b.saunier@hcdo.nl.
Gertraud Gradl-Dietsch, Email: gertraud.gradl-dietsch@lvr.de.
Meijuan Zhao, Email: mzhao@partners.org.
David Ring, Email: david.ring@austin.utexas.edu.
Appendix A. Additional patient and clinical characteristics per diagnostic group for the total cohort
| Variables | Total cohort N = 133 |
|||
|---|---|---|---|---|
| No UNE N = 34 (26) | UNE N = 81 (61) | P value | Other neuropathology N = 18 (14) | |
| Diabetes Mellitusa | ||||
| No | 31 (94) | 70 (88) | 0.50 | 16 (89) |
| Yes | 2 (6.1) | 10 (13) | 2 (11) | |
| Thyroid diseasea | ||||
| No | 29 (88) | 76 (95) | 0.26 | 17 (94) |
| Hypothyroidism | 3 (9.1) | 2 (2.5) | 1 (5.6) | |
| Hyperthyroidism | 1 (3.0) | 2 (2.5) | 0 (0) | |
| Chronic inflammatory diseasea | ||||
| No | 25 (76) | 61 (76) | 1.00 | 16 (89) |
| Yes | 8 (24) | 19 (24) | 2 (11) | |
| Treatment given | ||||
| Unknown | 15 (44) | 9 (11) | <0.001 | 7 (39) |
| Nonoperative | 19 (56) | 42 (52) | 11 (61) | |
| Operative | 0 (0) | 30 (37) | 0 (0) | |
Bold indicates statistically significant difference; Discrete variables as number (percentage); UNE: Ulnar neuropathy at the elbow; aData for 1 patient missing for the “No UNE” and the “UNE” groups.
Appendix B. Additional patient and clinical characteristics per diagnostic group looking at the cohorts with and without a previous UNE diagnosis
| Variables | Without previous UNE N = 117 |
With previous UNE N = 14 |
|||||
|---|---|---|---|---|---|---|---|
| No UNE N = 33 (28) | UNE N = 66 (56) | P value | Other neuropathology N = 18 (15) | No UNE N = 0 | UNE N = 14 (100) | Other neuropathology N = 0 | |
| Diabetes Mellitus | |||||||
| No | 31 (94) | 59 (89) | 0.71 | 16 (89) | 0 (0) | 11 (79) | 0 (0) |
| Yes | 2 (6.1) | 7 (11) | 2 (11) | 0 (0) | 3 (21) | 0 (0) | |
| Thyroid disease | |||||||
| No | 29 (88) | 62 (94) | 0.43 | 17 (94) | 0 (0) | 14 (100) | 0 (0) |
| Hypothyroidism | 3 (9.1) | 2 (3.0) | 1 (5.6) | 0 (0) | 0 (0) | 0 (0) | |
| Hyperthyroidism | 1 (3.0) | 2 (3.0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | |
| Chronic inflammatory disease | |||||||
| No | 25 (76) | 51 (77) | 1.00 | 16 (89) | 0 (0) | 10 (71) | 0 (0) |
| Yes | 8 (24) | 15 (23) | 2 (11) | 0 (0) | 4 (29) | 0 (0) | |
| Treatment given | |||||||
| Unknown | 14 (42) | 8 (12) | <0.001 | 7 (39) | 0 (0) | 1 (7.1) | 0 (0) |
| Nonoperative | 19 (58) | 34 (52) | 11 (61) | 0 (0) | 7 (50) | 0 (0) | |
| Operative | 0 (0) | 24 (36) | 0 (0) | 0 (0) | 6 (43) | 0 (0) | |
Bold indicates statistically significant difference; Discrete variables as number (percentage); UNE: Ulnar neuropathy at the elbow.
References
- 1.Palmer B.A., Hughes T.B. Cubital tunnel syndrome. J Hand Surg Am. 2010;35(1):153–163. doi: 10.1016/j.jhsa.2009.11.004. [DOI] [PubMed] [Google Scholar]
- 2.Mondelli M., Giannini F., Ballerini M., Ginanneschi F., Martorelli E. Incidence of ulnar neuropathy at the elbow in the province of Siena (Italy) J Neurol Sci. 2005;234(1-2):5–10. doi: 10.1016/j.jns.2005.02.010. [DOI] [PubMed] [Google Scholar]
- 3.Hulkkonen S., Lampainen K., Auvinen J., Miettunen J., Karppinen J., Ryhänen J. Incidence and operations of median, ulnar and radial entrapment neuropathies in Finland: a nationwide register study. J Hand Surg Eur. 2020;45(3):226–230. doi: 10.1177/1753193419886741. [DOI] [PubMed] [Google Scholar]
- 4.American Association of Electrodiagnostic Medicine, Campbell W. Guidelines in electrodiagnostic medicine. Practice parameter for electrodiagnostic studies in ulnar neuropathy at the elbow. Muscle Nerve Suppl. 1999;8:S171–S205. https://pubmed.ncbi.nlm.nih.gov/16921634/ Accessed. [PubMed] [Google Scholar]
- 5.Osei D.A., Groves A.P., Bommarito K., Ray W.Z. Cubital tunnel syndrome: incidence and demographics in a national administrative database. Neurosurgery. 2017;80(3):417–420. doi: 10.1093/neuros/nyw061. [DOI] [PubMed] [Google Scholar]
- 6.Naran S., Imbriglia J.E., Bilonick R.A., Taieb A., Wollstein R. A demographic analysis of cubital tunnel syndrome. Ann Plast Surg. 2010;64(2):177–179. doi: 10.1097/SAP.0b013e3181a2c63e. [DOI] [PubMed] [Google Scholar]
- 7.Mallette P., Zhao M., Zurakowski D., Ring D. Muscle atrophy at diagnosis of carpal and cubital tunnel syndrome. J Hand Surg Am. 2007;32(6):855–858. doi: 10.1016/j.jhsa.2007.03.009. [DOI] [PubMed] [Google Scholar]
- 8.An T.W., Evanoff B.A., Boyer M.I., Osei D.A. The prevalence of cubital tunnel syndrome: a cross-sectional study in a U.S. metropolitan cohort. J Bone Jt Surg - Am. 2017;99(5):408–416. doi: 10.2106/JBJS.15.01162. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Nardin R., Chapman K.M., Raynor E.M. Prevalence of ulnar neuropathy in patients receiving hemodialysis. Arch Neurol. 2005;62(2):271–275. doi: 10.1001/archneur.62.2.271. [DOI] [PubMed] [Google Scholar]
- 10.Dy C.J., Mackinnon S.E. Ulnar neuropathy: evaluation and management. Curr Rev Musculoskelet Med. 2016;9(2):178–184. doi: 10.1007/S12178-016-9327-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.American Association of Electrodiagnostic Medicine, American Academy of Neurology, American Academy of Physical Medicine and Rehabilitation Practice parameter for electrodiagnostic studies in ulnar neuropathy at the elbow: summary statement. Muscle Nerve. 1999;22(3):408–411. doi: 10.1002/(SICI)1097-4598. 199903)22:3<408::AID-MUS16>3.0.CO;2-7. [DOI] [PubMed] [Google Scholar]
- 12.American Academy of Orthopaedic Surgeons (AAOS) 2019. Clinical Practice Guidelines.https://www.aaos.org/quality/quality-programs/upper-extremity-programs/ [Google Scholar]
- 13.Yoon J.S., Walker F.O., Cartwright M.S. Ulnar neuropathy with normal electrodiagnosis and abnormal nerve ultrasound. Arch Phys Med Rehabil. 2010;91(2):318–320. doi: 10.1016/j.apmr.2009.10.010. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Shakir A., Micklesen P.J., Robinson L.R. Which motor nerve conduction study is best in ulnar neuropathy at the elbow? Muscle Nerve. 2004;29(4):585–590. doi: 10.1002/mus.10513. [DOI] [PubMed] [Google Scholar]
- 15.Kwon H.K., Lee H.J., Hwang M., Lee S.H. Amplitude ratio of ulnar sensory nerve action potentials in segmental conduction study: reference values in healthy subjects and diagnostic usefulness in patients with ulnar neuropathy at the elbow. Am J Phys Med Rehabil. 2008;87(8):642–646. doi: 10.1097/PHM.0b013e31816de327. [DOI] [PubMed] [Google Scholar]
- 16.Bartels R.H., Verbeek A.L. Risk factors for ulnar nerve compression at the elbow: a case control study. Acta Neurochir. 2007;149(7):669–674. doi: 10.1007/s00701-007-1166-5. ; discussion 674. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Thibault M.W., Robinson L.R., Franklin G., Fulton-Kehoe D. Use of the AAEM guidelines in electrodiagnosis of ulnar neuropathy at the elbow. Am J Phys Med Rehabil. 2005;84(4):267–273. doi: 10.1097/01.phm.0000156893.12433.c7. https://www.ncbi.nlm.nih.gov/pubmed/15785259 [DOI] [PubMed] [Google Scholar]