The Nature of the Relationship Between Smoking and Ulnar Neuropathy at the Elbow

Multiple Compression Syndromes of the Same Upper Extremity: Prevalence, Risk Factors, and Treatment Outcomes of Concomitant Treatment

PURPOSE

Multiple nerve compression syndromes can co-occur. Little is known about this coexistence, especially about risk factors and surgical outcomes. Therefore, this study aimed to describe the prevalence of multiple nerve compression syndromes in the same arm in a surgical cohort and determine risk factors. Additionally, the surgical outcomes of concomitant treatment were studied.

METHODS

The prevalence of surgically treated multiple nerve compression syndromes within one year was assessed using a review of patients' electronic records. Patient characteristics, comorbidities, and baseline scores of the Boston Carpal Tunnel Questionnaire were considered as risk factors. To determine the treatment outcomes of simultaneous treatment, patients who underwent concomitant carpal tunnel release (CTR) and cubital tunnel release (CubTR) were selected. The treatment outcomes were Boston Carpal Tunnel Questionnaire scores at intake and at 3 and 6 months after the surgery, satisfaction 6 months after the surgery, and return to work within the first year.

RESULTS

A total of 7,867 patients underwent at least one nerve decompression between 2011 and 2021. Of these patients, 2.9% underwent multiple decompressions for the same upper extremity within one year. The risk factors for this were severe symptoms, younger age, and smoking. Furthermore, the treatment outcomes of concomitant CTR and CubTR did not differ from those of CubTR alone. The median time to return to work after concomitant treatment was 6 weeks. Patients who underwent CTR or CubTR alone returned to work after 4 weeks.

CONCLUSIONS

Approximately 3% of the patients who underwent surgical treatment for nerve compression syndrome underwent decompression for another nerve within 1 year. Patients who report severe symptoms at intake, are younger, or smoke are at a greater risk. Patients with carpal and cubital tunnel syndrome may benefit from simultaneous decompression. The time to return to work may be less than if they underwent decompressions in separate procedures, whereas their surgical outcomes are comparable with those of CubTR alone.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Association of Acute Postoperative Pain and Cigarette Smoking With Cerebrospinal Fluid Levels of Beta-Endorphin and Substance P

Objectives: Cigarette smoking is associated with postoperative pain perception, which might be mediated by beta-endorphin and substance P. These effects on postoperative pain perception have never been investigated in human cerebrospinal fluid (CSF), which reflects biochemical alterations in the brain. Therefore, we investigated the associations among cigarette smoking, postoperative pain, and levels of beta-endorphin and substance P in human CSF.

Methods: We recruited 160 Chinese men (80 active smokers and 80 nonsmokers) who underwent lumbar puncture before anterior cruciate ligament reconstruction, and 5-ml CSF samples were collected. Pain visual analog scale (VAS) scores, post-anesthetic recovery duration (PARD), and smoking variables were obtained. CSF levels of beta-endorphin and substance P were measured.

Results: Compared to non-smokers, active smokers had significantly higher pain VAS (2.40 ± 0.67 vs. 1.70 ± 0.86, p < 0.001) and PARD scores (9.13 ± 2.11 vs. 7.27 ± 1.35, p = 0.001), lower CSF beta-endorphin (33.76 ± 1.77 vs. 35.66 ± 2.20, p = 0.001) and higher CSF substance P (2,124.46 ± 217.34 vs. 1,817.65 ± 302.14, p < 0.001) levels. Pain VAS scores correlated with PARD in active smokers (r = 0.443, p = 0.001).

Conclusions: Cigarette smoking is associated with increased postoperative pain intensity, shown by delayed pain perception, higher pain VAS scores, and lower beta-endorphin and higher substance P levels in the CSF of active smokers. The more extended postoperative pain perception is delayed, the more pain intensity increases.

Risk factors of asymptomatic reduction of motor conduction velocity of the ulnar nerve across the elbow

INTRODUCTION

The aim of the study was to check the risk factors for subjects with motor conduction velocity (MCV) reduction of the ulnar nerve across the elbow without symptoms/signs of ulnar neuropathy at the elbow (UNE) using a database of a previous multicenter case-control study on UNE patients.

METHODS

From the previous database, we extracted all asymptomatic UNE (A-UNE) and matched for age and sex with a control and UNE groups with a ratio of 1:2. Anthropometric factors were measured and all participants filled in a questionnaire on demographic, lifestyle factors, and medical history. One-sample proportion test and univariate and multivariate logistic regression analyses were performed.

RESULTS

We enrolled 64 A-UNE, 124 UNE, and 124 controls (mean age 53 years). There were more males with A-UNE than females (74.2%). The predominantly or exclusively concerned side of A-UNE was the right. Logistic regression showed that A-UNE was associated with diabetes (OR = 2.99, 95% CI = 1.21-7.39) and width of cubital groove (CGW) (OR = 0.89, 95%  CI = 0.81-0.97).

DISCUSSION

Risk factors for A-UNE are different from UNE. The prevalence of right side in A-UNE was not due to particular elbow postures. Diabetes is a risk factor, probably because MCV reduction of the ulnar nerve across the elbow was an early manifestation of asymptomatic polyneuropathy in diabetes. A-UNE is associated with narrow CGW as already demonstrated in UNE, even if the OR was higher in UNE than in A-UNE. Only future longitudinal studies will be able to check whether the A-UNE subjects develop symptoms and signs of true mononeuropathy with time.

Work-related risk factors for ulnar nerve entrapment in the Northern Finland Birth Cohort of 1966

Ulnar nerve entrapment (UNE) is the second most common entrapment neuropathy in the upper extremity. The aetiology of UNE is multifactorial and is still not fully understood. The aim of the study was to identify occupational risk factors for UNE and to determine whether smoking modifies the effects of work-related factors on UNE. The study population consisted of the Northern Finland Birth Cohort of 1966 (NFBC1966). In total, 6325 individuals active in working life participated at baseline in 1997. Occupational risk factors were evaluated by a questionnaire at baseline. The data on hospitalizations due to UNE were obtained from the Care Register for Health Care between 1997 and 2018. The incidence rate of hospitalization due to UNE was 47.6 cases per 100,000 person-years. After adjusting for confounders, entrepreneurs (Hazard ratio (HR) = 3.68, 95% CI 1.20–11.27), smokers (HR = 2.51, 95% CI 1.43–4.41), workers exposed to temperature changes (HR = 1.72, 95% CI 1.00–2.93), workers with physically demanding jobs (HR = 3.02, 95% CI 1.39–6.58), and workers exposed to hand vibration (HR = 1.94, 95% CI 1.00–3.77) were at an increased risk of hospitalization for UNE. Exposure to work requiring arm elevation increased the risk of hospitalization due to UNE among smokers (HR = 2.62, 95% CI 1.13–6.07), but not among non-smokers. Work-related exposure to vibration and temperature changes, and physically demanding work increase the risk of hospitalization for UNE. Smoking may potentiate the adverse effects of work-related factors on UNE.

Comorbidities, anthropometric, demographic, and lifestyle risk factors for ulnar neuropathy at the elbow: A case control study

We performed a prospective multicenter case-control study to explore the association between ulnar neuropathy at elbow (UNE) and body and elbow anthropometric measures, demographic and lifestyle factors, and comorbidities. Cases and controls were consecutively enrolled among subjects admitted to four electromyography labs. UNE diagnosis was made on clinical and neurographic findings. The control group included all other subjects without signs/symptoms of ulnar neuropathy and with normal ulnar nerve neurography. Anthropometric measurements included weight, height, waist, hip circumferences, and external measures of elbow using a caliper. The participants filled in a self-administered questionnaire on personal characteristics, lifestyle factors, and medical history. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) by fitting unconditional logistic regression models adjusted by center and education level. We enrolled 220 cases (males 61.8%; mean age 51.7 years) and 460 controls (47.4% males; mean age 47.8 years). At multivariable analysis, UNE was associated to male gender (OR = 2.4, 95%CI = 1.6-3.7), smoking habits (>25 pack-years (OR = 2.3, 95%CI = 1.3-4.1), body mass index (OR = 1.05, 95%CI 1.01-1.10), polyneuropathies (OR = 4.1, 95%CI 1.5-11.5), and leaning with flexed elbow on a table/desk (OR = 1.5, 95%CI 1.0-2.2). Cubital groove width (CGW) turned out to be negatively associated with UNE (OR = 0.80, 95%CI = 0.74-0.85). Our study suggests that some personal factors especially anthropometric measures of the elbow may play a role in UNE pathogenesis as the measures of wrist in CTS. We demonstrated that for each millimeter of smaller CGW the risk of idiopathic UNE increases of 25%.

The external elbow measure as surrogate of the anatomical width of cubital groove and possible risk factor of ulnar neuropathy at the elbow

Introduction: There are no studies on elbow anthropometry in ulnar neuropathy at the elbow (UNE). We aimed to test the interrater agreement of external elbow measurements with caliper, the matching of external width of cubital groove (WCG) measures with those obtained through conventional radiography (XR) and ultrasonography (US). The final aim was to evaluate the differences of anthropometric elbow and body measures between UNE cases and controls with multicenter prospective study.Materials and methods: After common training of five observers for external elbow and body anthropometric measurements, we assessed the interrater agreement of measures in a single blind measurement session in 16 healthy volunteers. Then we verified if external WCG measures in eight and four of the above 16 subjects matched with those obtained with US and XR. Finally, we enrolled 40 consecutive idiopathic UNE cases in four electromyographic labs matched for sex and age with 40 controls to evaluate the differences of anthropometric measures.Results: There was high interrater agreement of all anthropometric body and elbow measures (Kendal's and interclass correlation coefficients between 0.84 and >0.9). We found high relations between WCG caliper measures and those obtained with US and XR (r > 0.9). WCG was smaller in cases than in controls (13.2 vs.15.7 mm, p < 0.001). There were no differences in body anthropometric measures (BMI and waist-to-hip ratio).Conclusion: The external measurement of WCG is reliable and reproducible and may be risk factor of UNE. Future studies should be performed in lager samples evaluating the relations with lifestyle and occupational factors.

Laterality and risk factors for ulnar neuropathy at the elbow

BACKGROUND

Ulnar neuropathy at the elbow (UNE) is the second commonest entrapment neuropathy after carpal tunnel syndrome (CTS) and yet the laterality is not well delineated. Our aim was to establish the laterality of UNE in a large cohort of patients.

METHODS

All new patients with clinical and electrodiagnostic (EDX) confirmed UNE over a 13-year period were included. We used multivariate analysis to examine potential predictors of laterality, and unilateral vs bilateral UNE.

RESULTS

Of 880 cases, 61% were left-sided and 39% right-sided. These proportions did not change regardless of the handedness of the patient. Patients with bilateral UNE were much more likely to be older male and have a variety of comorbidities.

CONCLUSIONS

UNE appears to be present on the left 50% more often than on the right, regardless of the patient's handedness.

Clinical Findings and Electrodiagnostic Testing in Ulnar Neuropathy at the Elbow and Differences According to Site and Type of Nerve Damage

OBJECTIVE

The aim of the study was to evaluate the clinical and electrodiagnostic testing in ulnar neuropathy at the elbow and differences according to site (humeroulnar arcade vs. retroepicondylar groove) and injury physiopathology (axonal vs. demyelinating), through prospective multicenter case-control study.

DESIGN

Cases and controls were matched by age and sex. Ulnar neuropathy at the elbow diagnosis was made on symptoms. Statistical analysis was performed using Mann-Whitney, χ, and analysis of variance tests.

RESULTS

One hundred forty-four cases and 144 controls were enrolled. Sensory loss in the fifth finger had the highest sensitivity (70.8%) compared with clinical findings. Motor conduction velocity across elbow reached the highest sensitivity (84.7%) in localizing ulnar neuropathy at the elbow recording from at least one of the two hand muscles (first dorsal interosseous and abductor digiti minimi). Abnormal sensory action potential amplitude from the fifth finger occurred more frequently in axonal than in demyelinating forms. Differences between retroepicondylar groove and humeroulnar arcade regarded conduction block and job type.

CONCLUSIONS

Clinical findings have less usefulness than electrodiagnostic testing in ulnar neuropathy at the elbow diagnosis. Motor conduction velocity across elbow recorded from both abductor digiti minimi and first dorsal interosseous increases diagnostic accuracy. Axonal forms have greater clinical and electrodiagnostic testing severity than demyelinating forms, which are more frequent in retroepicondylar groove. Manual workers prevailed in humeroulnar arcade. These findings may be helpful in prognostic and therapeutic approaches.

Smoking is associated with ulnar nerve entrapment: a birth cohort study

Ulnar nerve entrapment is the second most common compression neuropathy of the upper extremity. It has been associated with smoking in cross-sectional studies. Our aim was to study whether smoking is associated with ulnar nerve entrapment. The study population consisted of the Northern Finland Birth Cohort 1966 participants, who attended the 31-year follow-up in 1997 (N = 8,716). Information on smoking, body mass index (BMI), long-term illnesses, and socio-economic status were recorded at baseline in 1997. Data on hospitalizations due to ulnar nerve entrapment neuropathies was obtained from the Care Register for Health Care, 1997-2016. Hazard ratios (HR) with 95% confidence intervals (CI) and population attributable risk (PAR) were calculated adjusted for gender, BMI and socio-economic status. 66 patients were diagnosed with ulnar nerve entrapment in the follow-up 1997-2016. Before the age of 31 years, smoking ≤10 pack years associated with more than doubled (HR = 2.57, 95% CI = 1.29-5.15) and smoking >10 pack years with more than five-folded (HR = 5.61, 95% CI = 2.80-11.23) risk for ulnar nerve entrapment compared to non-smokers in the adjusted analyses. Adjusted PAR for smoking (reference of no smoking) was 53.6%. In our study, smoking associated with increased risk for ulnar nerve entrapment, accounting for considerable proportion of increased risk.

Tobacco use predicts poorer clinical outcomes and higher post-operative complication rates after open elbow arthrolysis

INTRODUCTION

Tobacco use is a worldwide public health problem, and has been found to be a predisposing factor for adverse functional outcomes and increased postoperative complication rates after various orthopedic operations. The purpose of this study was to determine the potential impact of tobacco use on open arthrolysis for post-traumatic elbow stiffness.

MATERIALS AND METHODS

A database search identified 145 patients with open arthrolysis performed for post-traumatic elbow stiffness; these were divided into three groups: current tobacco users (37), former users (28), and nonusers (80). All surgeries were performed using the same technique by the same doctor. General patient data, functional performance, and complications were documented and analyzed.

RESULTS

Demographic data and disease characteristics were comparable at baseline. Postoperatively, significant differences were found among the three groups in terms of range of motion (P < 0.001), Mayo Elbow Performance Score (P = 0.006), visual analog scale score for pain (P = 0.015), Dellon classification for ulnar nerve symptoms (P = 0.013), and total complication rates (P < 0.001). The current tobacco users group had the poorest clinical outcomes and highest complication rates, while no significant differences were found between former users and nonusers.

CONCLUSIONS

Current tobacco users reported increased risk of poorer clinical outcomes and higher postoperative complication rates after open arthrolysis. Former users were found to have outcomes similar to those of nonusers. This study underlines the importance of discontinuing tobacco use for patients with post-traumatic elbow stiffness who are considering open arthrolysis.

LEVEL OF EVIDENCE

Level III; Retrospective Cohort Design; Therapeutic Study.

Relationship between Smoking and Outcomes after Cubital Tunnel Release

Purpose

Several studies have drawn a connection between cigarette smoking and cubital tunnel syndrome. One comparison article demonstrated worse outcomes in smokers treated with transmuscular transposition of the ulnar nerve. However, very little is known about the effect that smoking might have on patients who undergo ulnar nerve decompression at the elbow. The purpose of this study is to evaluate the effect of smoking preoperatively on outcomes in patients treated with ulnar nerve decompression.

Materials and Methods

This study used a survey developed from the comparison article with additional questions based on outcome measures from supportive literature. Postoperative improvement was probed, including sensation, strength, and pain scores. A thorough smoking history was obtained. The study spanned a 10-year period.

Results

A total of 1,366 surveys were mailed to former patients, and 247 surveys with adequate information were returned. No significant difference was seen in demographics or comorbidities. Patients who smoked preoperatively were found to more likely relate symptoms of pain. Postoperatively, nonsmoking patients generally reported more favorable improvement, though these findings were not statistically significant.

Conclusion

This study finds no statistically significant effect of smoking on outcomes after ulnar nerve decompression. Finally, among smokers, there were no differences in outcomes between simple decompression and transposition.

Ulna Nerve Decompression at the Elbow in Patients with Normal Nerve Conduction Tests

BACKGROUND

Ulna nerve compression at the elbow is the second most common neuropathy of the upper limb. It has been suggested that nerve conduction tests are required to correctly make the diagnosis. The aim of this study was to assess whether patients with normal nerve conduction testing benefitted from surgical release of the ulna nerve.

METHODS

56 patients with symptoms of ulna nerve compression at the elbow were evaluated prospectively. All patients underwent electrophysiology testing followed by ulna nerve decompression irrespective of the results of the electrophysiology testing. Functional scores using the QuickDASH and PEM score were collected up to 12 months post-surgery.

RESULTS

No difference was found between the group with normal and the group with abnormal electrophysiology studies.

CONCLUSIONS

We conclude that patients who clinically have ulna nerve compression still benefit from ulna nerve decompression despite normal nerve conduction tests.