Modern Treatment of Cubital Tunnel Syndrome: Evidence and Controversy

Cubital tunnel syndrome is the second most common peripheral mononeuropathy in the upper extremity. However, the diagnosis and treatment of cubital tunnel syndrome remains controversial without a standard algorithm. Although diagnosis can often be made from the patient's history and physical examination alone, electrodiagnostic studies, ultrasound, computed tomography (CT), and magnetic resonance image (MRI) can also be useful in diagnosing the disease and selecting the most appropriate treatment option. Treatment options include conservative nonoperative techniques as well as various surgical options, including in situ decompression with or without transposition, medial epicondylectomy, and nerve transfer in advanced disease. The purpose of this review is to summarize the most up-to-date literature regarding cubital tunnel syndrome and propose a treatment algorithm to provide clarity about the challenges of treating this complex patient population.

Features of the Ulnar Nerve Predicting Postoperative Prognosis in Idiopathic Cubital Tunnel Syndrome: Three Distinct Features of the Ulnar Nerve

PURPOSE

This retrospective case-control study was performed to determine the relationships between features of the ulnar nerve and postoperative outcomes following in situ decompression in idiopathic cubital tunnel syndrome (CuTS).

METHODS

The study population consisted of 86 patients who had undergone surgery for CuTS. We evaluated demographic factors, hand dominance, symptom onset time, time from diagnosis to surgery, findings of electrodiagnosis (nerve conduction velocity/electromyography), and preoperative clinical status. Intraoperatively, the ulnar nerve was defined as a definitively compressed, abnormally enlarged, or inflammatory lesion. Clinical improvements were evaluated at least 2 years after surgery.

RESULTS

Fifty-four patients showed improvement after surgery in terms of the modified McGowan grade and were designated as group 1. Meanwhile, 32 patients with unchanged or aggravated status were classified as group 2. Preoperative status, as determined by the modified McGowan grade, Boston Symptom Severity Scale score, severity of electrodiagnosis, and predominant symptoms were similar between the groups (all, P > 0.05). On regression analysis, only the classification of nerve lesions and the time from diagnosis to surgery had an impact on postoperative outcome (all, P < 0.05). Especially, enlarged ulnar lesion predicted poor prognosis (P = 0.003).

CONCLUSIONS

Ulnar nerve enlargement, grossly detected intraoperatively, and long interval between diagnosis and surgery were independently associated with poor prognosis of CuTS. Among the anatomic structures involved in the generation of CuTS, the medial epicondyle showed a strong association with enlarged nerve lesions.

Predictors of surgical outcomes after in situ ulnar nerve decompression for cubital tunnel syndrome

Background

In the treatment of cubital tunnel syndrome (CuTS), in situ ulnar nerve decompression is commonly used. This study aims to investigate predictive factors for poor recovery and ulnar nerve instability following this procedure.

Methods

We enrolled 235 patients who underwent in situ ulnar nerve decompression for the treatment of CuTS from January 2010 to December 2014. All patients underwent >2 years' follow-up. The primary outcome was postoperative recovery, which was assessed by Messina's criteria, and the secondary outcome was postoperative ulnar nerve instability. Potential risk factors were collected from demographic data and electrodiagnostic test, which included age, gender, body mass index, history of tobacco or alcohol use, history of major medical comorbidities, disease duration, preoperative severity, motor conduction velocity, and sensory conduction velocity.

Results

A total of 208 patients (88.5%) had satisfactory outcomes, while the other 27 patients (11.5%) had not. There were 25 patients (10.6%) showing postoperative ulnar nerve instability during follow-up. The multivariate analysis showed that only severe preoperative symptom (odds ratio [OR], 3.06; 95% confidence interval [CI], 2.16-4.32) was associated with unsatisfactory postoperative outcomes in patients with CuTS (P<0.001). In the model investigating independent factors associated with postoperative ulnar nerve instability, we found that young age (OR, 2.41; 95% CI, 1.63-3.58) was associated with the incidence of postoperative ulnar nerve instability (P<0.001).

Conclusion

We found that severe preoperative symptom was associated with unsatisfactory postoperative outcomes, and young age was a risk factor for the incidence of postoperative ulnar nerve instability. Patients with these risk factors should be informed of the possibility of worse surgical outcomes.

A minimally invasive approach for cubital tunnel release and ulnar nerve transposition

OBJECTIVES

The aim of the study is to introduce a new minimally invasive technique for ulnar nerve release and transposition.

METHODS

From January 2010 to May 2011, 51 patients with cubital tunnel syndrome were treated through a 1.5 to 2 cm incision. Limb functional recovery, scar esthetics, sensitivity of scar, numbness of the operating area, and patient satisfaction were assessed.

RESULTS

No wound hematoma nor infection was observed in the group. The time of operation was 36 ± 17.2 minutes. At the final follow-up of 63 ± 7.3 months, 2-point discrimination of the small finger was improved from 6.3 ± 2.2 mm to 5.2 ± 2.4 mm. Grip and pinch strength of the hand were improved from 14.2 ± 7.7 kg and 3.7 ± 2.4 kg to 35.2 ± 12.7 kg and 4.1 ± 2.8 kg, respectively. The motor nerve conduction velocity was improved from 36.5 ± 11.2 to 44.6 ± 6.7 (m/sec). The Disabilities of the Shoulder, Arm, and Hand questionnaire score was improved from 37.2 ± 23.8 to 10.5 ± 9.6. No patients reported scar pain, sensitivity of scar, or numbness of the operating area. No revision surgery was needed. Michigan Hand Outcome score for aesthetics was 94.6%±5.1 and satisfaction was 92 ± 8, respectively. We obtained 33 excellent, 12 good, 5 fair, and 1 poor result.

CONCLUSION

Ulnar nerve decompression with anterior transposition can be safely and effectively accomplished through the small incision. It can be an alternative technique producing good appearance.

Cross-sectional area of the ulnar nerve after decompression at the cubital tunnel

A total of 48 patients undergoing surgical decompression of the ulnar nerve at the cubital tunnel between February 2010 and May 2013 were retrospectively studied to determine changes in the cross-sectional area of the nerve by the technique of neurosonography. The mean follow-up was 46 months. Post-operative follow-up examination of the cross-sectional area of the ulnar nerve showed a slight reduction in the mean value from 13.8 mm(2) (pre-operative) to 12.9 mm(2) (post-operative). Of the 48 patients, 36 showed a reduction in the cross-sectional area. No correlation was detected between the clinical and sonographic outcomes. Ultrasound seems to be of limited value in the post-operative assessment of patients with entrapment neuropathy of the ulnar nerve.

LEVEL OF EVIDENCE

IV.

Predicting Revision Following In Situ Ulnar Nerve Decompression for Patients With Idiopathic Cubital Tunnel Syndrome

PURPOSE

To determine the incidence of revision and potential risk factors for needing revision surgery following in situ ulnar nerve decompression for patients with idiopathic cubital tunnel syndrome (CTS).

METHODS

We conducted a retrospective chart review of all patients treated at 1 specialty hand center with an open in situ ulnar nerve decompression for idiopathic CTS from January 2006 through December 2010. Revision incidence was determined by identifying patients who underwent additional surgeries for recurrent or persistent ulnar nerve symptoms. Bivariate analysis was performed to determine which variables had a significant influence on the need for revision surgery.

RESULTS

Revision surgery was required in 3.2% (7 of 216) of all cases. Age younger than 50 years at the time of index decompression was the lone significant predictor of need for revision surgery. Other patient factors, including gender, diabetes, smoking history, and workers' compensation status were not predictive of the need for revision surgery. Disease-specific variables including nerve conduction velocities, McGowan grading, and predominant symptom type were also not predictive of revision.

CONCLUSIONS

For patients with idiopathic CTS, the risk of revision surgery following in situ ulnar nerve decompression is low. However, this risk was increased in patients who were younger than 50 years at the time of the index procedure. The findings of this study suggest that, in the absence of underlying elbow arthritis or prior elbow trauma, in situ ulnar nerve decompression is an effective, minimal-risk option for the initial surgical treatment of CTS.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic III.