The Association Between Concomitant Ulnar Nerve Compression at the Elbow and Carpal Tunnel Syndrome

Abstract

Background: Many patients treated for ulnar nerve compression at the elbow (UNE) are concomitantly treated for carpal tunnel syndrome (CTS). We sought to investigate the association between the conditions. Methods: The Statewide Planning and Research Cooperative System (SPARCS) database was used to determine the number of patients with UNE concomitantly treated for CTS in New York State from 2003 to 2014. We then retrospectively reviewed each patient who received surgical treatment for UNE (n = 222 patients) or CTS (n = 1063 patients) at our tertiary care institution in 2014 and 2015 to assess concomitant treatment. Results: In the SPARCS database, the percentage of patients surgically treated for concomitant UNE and CTS steadily increased from 23% in 2003 to 45% in 2014. At our institution, 50 of 222 patients (23%) surgically treated for UNE underwent concomitant carpal tunnel releases. For concomitantly treated patients, 94% had examinations consistent with UNE and CTS, 87% of patients had median nerve compression on electrodiagnostic tests, and 72% of patients had UNE on electrodiagnostic tests. Conclusions: Most patients concomitantly treated for UNE and CTS have objective findings of both conditions. At least one-fourth of patients indicated for operative ulnar nerve release also require a carpal tunnel release—far beyond the prevalence of CTS in the general population. A diagnosis of UNE merits a comprehensive workup by the treating surgeon and a high suspicion for concomitant median nerve compression.

Introduction

Carpal tunnel syndrome (CTS) and ulnar neuropathy at the elbow (UNE) are the 2 most commonly diagnosed compressive neuropathies, with a reported prevalence of 2.7% to 6.8% and 1.8% to 5.9% in the general population, respectively.^1,2 Despite being such common diagnoses, little is known about the treatment of these conditions in tandem. Anecdotal observations in our own practice revealed a remarkably high rate of patients with UNE concomitantly treated for CTS. Several authors have previously hinted at a link between UNE and CTS. Using data from other studies, Cross and Matullo reported a 20% to 25% rate of UNE patients with concomitant CTS symptoms.³ Day et al.⁴ in a study of demographic factors leading to surgical treatment of UNE and CTS found that 19 (37%) of the 51 patients in their cohort with UNE had concomitant CTS. The converse was not true, as only 19 of 240 patients (8%) with CTS had concomitant UNE.⁴ However, they did not expand upon these findings.⁴ Zhang et al⁵ recently published an article looking at the demographics of patients who develop carpal and cubital tunnel syndromes. Twenty-two percent of patients in their cohort who underwent cubital tunnel release also underwent carpal tunnel release.⁵ Chimenti et al⁶ in a recent study of symptom resolution after cubital and carpal tunnel releases noted that in their clinical experience, “the two diagnoses may frequently occur together.” Our initial aim of this study was to see whether our own anecdotal findings and those previously suggested in the literature were true on a large scale.

Our primary hypothesis was that patients requiring cubital tunnel release underwent carpal tunnel release at a greater rate than the general population. If true, this begged the further question of whether objective findings such as electrodiagnostic tests aligned with the performed procedures. Our second hypothesis was that preoperative testing would not align with the performed surgeries and that surgeon overtreatment potentially contributed to the high rate of concomitance. An et al,² in a recent 1001 subject cross-sectional population survey published in the Journal of Bone and Joint Surgery (JBJS), found that 69% of respondents who identified as having symptoms of peripheral neuropathy met criteria for both UNE and CTS.² While this would support a relationship between UNE and CTS, these data were based on voluntary responses to questionnaires and neither addressed the incidence of surgical treatment nor included electrodiagnostic studies.² Furthermore, upper extremity literature is rife with examples of overtreatment, from pediatric distal forearm injuries to wrist sprains to clavicle fractures.^7,8,9,10 The purpose of this study was 2-fold: first, to determine the incidence of concomitantly treated CTS and UNE, and, second, to investigate to what extent the degree of preoperative examinations and tests was predictive of surgical treatment.

Materials and Methods

Our initial analysis sought to examine the rate of concomitant surgery for UNE and CTS in large cohorts. We used the Statewide Planning and Research Cooperative System (SPARCS) to search for every patient who underwent operative treatment for UNE or CTS from 2003 to 2014 (84 829 patients). Patients were searched by Current Procedural Terminology (CPT) codes for open carpal tunnel release (CPT 64721), endoscopic carpal tunnel release (CPT 29848), and neuroplasty and/or transposition of ulnar nerve at elbow (CPT 64718). We then analyzed these data to determine how many individual patients with UNE were also treated for CTS per year. The same cohort of concomitantly treated patients was used to determine the percentage of patients with UNE treated for CTS and the percentage of patients with CTS treated for UNE. For example, if 100 patients were treated for CTS, 50 patients were treated for UNE and 5 patients were treated for both conditions; 5% of patients with CTS would have been concomitantly treated for UNE and 10% of patients with UNE would have been concomitantly treated for CTS. The initial complaint (symptoms of CTS, UNE, or both) was not determinable from the SPARCS database, nor was it considered pertinent. The purpose of this analysis was to determine the rate of concomitant surgical treatment of CTS and UNE on a large scale, regardless of treatment indications.

The second portion of our analysis was an internal review of patients treated at our tertiary care institution. This was conducted to corroborate the rate of surgery for CTS, UNE, and concomitant disease and to determine whether the subjective complaints and objective measures were consistent with the conditions for which those patients were surgically treated. We used our electronic medical record system (EPIC Systems Corporation, Verona, Wisconsin) to identify every patient who had a procedure using the above 3 CPT codes in 2014 and 2015 (as no surgeon at our institution performs endoscopic cubital tunnel releases, no patient received this surgery). Demographic information was collected (Table 1). The incidence of concomitantly performed ipsilateral carpal tunnel and cubital tunnel releases was calculated. Whether symptoms of UNE or CTS appeared first in concomitantly treated patients was not considered pertinent, as by default patients in this group received a surgical treatment for both conditions. We then conducted a retrospective review of the clinical examination and nerve conduction findings for patients treated for CTS, UNE, and concomitant CTS and UNE. Clinical and electrophysiological data were collected for every identified patient treated for UNE or concomitant UNE/CTS. Because so many patients treated for CTS were identified, clinical and electrophysiological data were collected on 50 consecutive patients treated for CTS. The number of patients enrolled in each group was based on a power analysis indicating it was necessary to enroll 111 total patients, or 37 in each group. As 50 patients with concomitant UNE and CTS were identified over the 2-year period, we matched this number when analyzing data for patients with CTS. The threshold significance of our power analysis was based on pilot study of patients in our cohort that included an examination of the mean differences in nerve conduction study parameters between those with isolated CTS or UNE. To standardize the electrophysiological data between different electrophysiologists and testing facilities, nerve compression was determined based on the neurologist impression for median nerve compression at the wrist and UNE. In all patients, conservative management (local steroid injection and/or bracing) was attempted prior to surgery unless there was evidence of motor weakness or muscle atrophy.

Table 1.

Demographics.

	CuTR	CuTR/CTR	p
Total patients	222	50	n/a
% Women	42	40	.944
% Diabetes mellitus	6.4	15.4	.043
% Cervical radiculopathy	11.1	19.2	.127

Note. CuTR = cubital tunnel release; CTR = carpal tunnel release.

Statistical analyses were conducted to determine the percentage of patients treated for each condition that had clinical and electrophysiological findings of median nerve compression at the wrist and/or UNE. Mann-Whitney U tests were conducted to assess differences in treatment rates based on positive clinical and nerve conduction findings. Subgroup analyses were conducted to determine whether the comorbid conditions of diabetes mellitus and cervical radiculopathy had an effect on which patients with UNE underwent concomitant carpal tunnel release. Comorbidity data were extracted from the existing medical record. For ease of designation in this article, “cubital tunnel release” encompasses all forms of ulnar nerve decompression at the elbow, with or without transposition.

Results

In New York State from 2003 to 2014, the percentage of patients treated for UNE who were concomitantly treated for CTS increased over time from 23% in 2003 to 45% in 2014 (Figure 1). The number of patients treated for CTS who were concomitantly treated for UNE increased from 3.4% in 2003 to 6.0% in 2014 (Figure 1).

Figure 1.

Percentage of concomitant cases in New York State.

Note. Statewide Planning and Research Cooperative System Database Analysis. CTR = carpal tunnel release; CuTR = cubital tunnel release.

At our institution, 50 of 222 patients (22.5%) underwent concomitant carpal tunnel release at the time of their cubital tunnel surgery, yet only 50 of 1063 patients (4.7%) treated for CTS underwent concomitant treatment for UNE (Figure 2). Clinical examination results, including specific examination tests, can be seen in Table 2. For patients treated for CTS alone, 100% had median nerve dysfunction symptoms and 6% had ulnar nerve dysfunction symptoms. For patients treated for UNE alone, 100% had ulnar nerve dysfunction symptoms and 18% had median nerve dysfunction symptoms. For concomitantly treated patients, 100% of patients had an abnormal examination, 94% had symptoms of median nerve dysfunction, and 94% had symptoms of ulnar nerve dysfunction. Conservative management was trialed prior to surgery in 72% of patients treated for CTS, 68% of patients treated for UNE, and 45% of patients treated concomitantly for both conditions. Some evidence of motor weakness was noted in all cases where conservative management was not trialed.

Figure 2.

Percentage of concomitantly treated patients by year.

Note. Institutional data. CTR = carpal tunnel release; CuTR = cubital tunnel release.

Table 2.

Percentage of Patients With Positive Electrodiagnostic and Clinical Findings, by Treatment Group.

	CuTR	CTR	CuTR/CTR
Median nerve compression at wrista	13.5	100.0	87.5
Ulnar nerve compression at elbowa	81.6	6.1	72.4
Numbness (median distribution)	13	100	58
Numbness (ulnar distribution)	100	6	70
+ Tinels at wrist (median)	10	74	87
+ Tinels at elbow (ulnar)	76	0	74
Thenar wasting/weakness	5	26	32
Intrinsic wasting/weakness	34	0	16
Any clinical sign of carpal tunnel syndrome	18	100	94
Any clinical sign of ulnar nerve compression at the elbow	100	6	94

Note. CuTR = cubital tunnel release; CTR = carpal tunnel release.

^aBased on neurologist impression of electrodiagnostic study.

For patients treated for concomitant CTS and UNE, 87% had electrodiagnostic findings consistent with median nerve compression at the wrist, and 72% had electrodiagnostic findings consistent with UNE (Table 2). For patients who underwent only cubital tunnel release, 81.6% had electrodiagnostic findings consistent with UNE, and 13.5% had electrodiagnostic findings consistent with median nerve compression at the carpal tunnel. For patients who underwent only carpal tunnel release, 100% had electrodiagnostic findings consistent with CTS, and 6.1% had electrodiagnostic findings consistent with UNE. In all, 6.4% of patients who underwent cubital tunnel release and 15.4% of concomitantly treated patients had diabetes mellitus (P = .043), and 11.1% of patients who underwent cubital tunnel release and 19.2% of concomitantly treated patients had cervical radiculopathy (P = .127).

Discussion

In our initial analysis of patients treated in New York State, we found that the percentage of patients undergoing cubital tunnel release who underwent concomitant carpal tunnel release was extremely high (22%-45%) and rapidly increased from 2003 to 2014 (Figure 1). These data could be concerning for physician overtreatment (surgical treatment in the absence of positive clinical or electrodiagnostic findings), as one would not expect a 2-fold increase in the rate of true concomitance over 12 years. It is also possible that older nerve conduction studies did not routinely test for both CTS and UNE, and thus, fewer concomitant cases were diagnosed. Previous institutional systems, surgical protocols, and financial incentives may have also led providers to treat these conditions in separate anesthesia events that may have preceded our data collection.

In our institutional data for 2014 and 2015, 23% of patients undergoing cubital tunnel release had an ipsilateral carpal tunnel release. Our finding of 4.7% of patients with CTS undergoing concomitant cubital tunnel release is roughly on par with the incidence of surgically treated UNE in the general population as reported by An et al² and Osei et al. However, our finding of 23% of patients with UNE undergoing concomitant carpal tunnel release is substantially higher than the 2.7% to 6.8% prevalence of CTS in the general population. This suggests that for patients with UNE, the development of CTS may not be due to random chance. The clinical and nerve conduction studies in our internal data further supported these assumptions by showing that the gross majority of patients concomitantly treated for UNE and CTS did in fact have objective findings of both conditions. These findings lead us to believe that UNE, when accompanied by CTS, is a manifestation of a multinerve compressive neuropathy and not 2 different compressive neuropathies occurring concurrently yet independently of one another.

While identifying UNE as part of a global compressive neuropathy has not been previously described, there are multiple examples in the literature alluding to multinerve compressive neuropathies of the upper extremity. Chimenti et al⁶ published a prospective study of 20 patients with combined cubital and carpal tunnel syndromes who underwent simultaneous release and noted that in their experience the 2 syndromes “frequently occur together.”⁶ They found that 70% of their cohort reported at least one preoperative “extra-anatomic” nerve compression symptom outside of their median or ulnar nerve distributions, and of these patients, 80% had resolution of their extra-anatomic symptoms after combined carpal and cubital tunnel releases.⁶ Cross and Matullo described 17 patients who underwent 19 ipsilateral endoscopic carpal and cubital tunnel releases by a single surgeon over an 8-month period.³ They noted that intraoperatively all patients had evidence of median nerve compression at the carpal tunnel and the ulnar nerve compression under Osborne’s ligament, and 88% of patients had resolution in numbness in both distributions.³ Citisli et al¹¹ published a case of a healthy 38-year-old man with left carpal and cubital tunnel syndrome as well as right cubital tunnel syndrome. Vimercati et al¹² described a case of a healthy 22-year-old male chef who demonstrated symptoms of bilateral cubital and carpal tunnel syndromes.

The pathophysiology of these findings is not clear at this time. Diabetes mellitus has been shown to be a risk factor for both UNE and CTS. Naran et al¹³ in a study of 74 patients with UNE found that 23% of patients in their cohort were diabetic. Zhang et al⁵ did not find a statistically significant difference in rates of diabetes in patients surgically treated for CTS, UNE, or both conditions. In our study, there were significantly more patients with diabetes in the concomitantly treated group than the UNE alone group. However, patients with diabetes still accounted for only 15% of the patients treated for both UNE and CTS, and thus, we do not feel that the high rate of concomitance can be primarily or even largely attributed to diabetes.

This study had several limitations. Both our review of the SPARCS database and our internal review of our institutional medical record were retrospective in nature. Our data also exclude patients who did not have simultaneous ipsilateral median and ulnar nerve releases but had both procedures performed within a short period. It is possible that the incidence of concomitant surgery would be even greater if patients who underwent both procedures in a staged manner were included. For concomitantly treated patients, we did not discern which condition was “more” symptomatic or the “primary complaint,” as this study’s goal was to establish whether concomitantly treated patients had objective findings of both conditions. To standardize the results of electrodiagnostic studies performed at different locations, we relied on the neurologists’ impression. While this is not a fully objective measure, we believe that this is the most straightforward measure available in determining the presence or absence of the relevant compressive neuropathy. The retrospective nature of the data also does not allow us to quantify the severity of the symptoms. Therefore, while we can determine the presence of clinical signs and symptoms of CTS and/or UNE, we cannot reliably discern the degree of clinical severity.

Most patients treated for concomitant UNE and CTS at our institution did have objective findings of both conditions. While CTS appears to be a relatively isolated disorder, at least one-quarter of the patients treated for UNE require a concomitant carpal tunnel release—far beyond the prevalence of CTS in the general population. In these cases, UNE and CTS may not be independent diagnoses but rather a manifestation of a global compressive neuropathy and/or as a result of different pathophysiology. The cause of the increase in concomitantly treated cases over time seen in the New York State data is not clear at this time, but does clearly corroborate a high rate of concomitantly treated UNE and CTS at all time points. Based on these data, we believe that any diagnosis of UNE merits a comprehensive workup by the treating surgeon and a high suspicion for concomitant median nerve compression. However, despite the apparent link between UNE and CTS, strict clinical and electrophysiological criteria should be adhered to when indicating a patient for surgery to avoid overtreatment.