Double entrapment neuropathy of the ulnar nerve at the elbow and the wrist : double crush syndrome?

BACKGROUND: Double crush syndrome refers to a nerve in the proximal region being compressed, affecting its proximal segment. Instances of this syndrome involving ulnar and cubital canals during ulnar neuropathy are rare. Diagnosis solely through clinical examination is challenging. Although electromyography (EMG) and nerve conduction studies (NCS) can confirm neuropathy, they do not incorporate inching tests at the wrist, hindering diagnosis confirmation. We recently encountered eight cases of suspected double compression of ulnar nerve, reporting these cases along with a literature review. METHODS: The study included 5 males and 2 females, averaging 45.6 years old. Among them, 4 had trauma history, and preoperative McGowan stages varied. Ulnar neuropathy was confirmed in 7 cases at both cubital and ulnar canal locations. Surgery was performed for 4 cases, while conservative treatment continued for 3 cases. RESULTS: In 4 cases with wrist involvement, 2 showed ulnar nerve compression by a fibrous band, and 1 had nodular hyperplasia. Another case displayed ulnar nerve swelling with muscle covering. Among the 4 surgery cases, 2 improved from preoperative McGowan stage IIB to postoperative stage 0, with significant improvement in subjective satisfaction. The remaining 2 cases improved from stage IIB to IIA, respectively, with moderate improvement in subjective satisfaction. In the 3 cases receiving conservative treatment, satisfaction was significant in 1 case and moderate in 2 cases. Overall, there was improvement in hand function across all 7 cases. CONCLUSION: Typical outpatient examinations make it difficult to clearly differentiate the two sites, and EMG tests may not confirm diagnosis. Therefore, if a surgeon lacks suspicion of this condition, diagnosis becomes even more challenging. In cases with less than expected postoperative improvement in clinical symptoms of cubital tunnel syndrome, consideration of double crush syndrome is warranted. Additional tests and detailed EMG tests, including inching tests at the wrist, may be necessary. We aim to raise awareness double crush syndrome with ulnar nerve, reporting a total of 7 cases to support this concept.

Patterns and parameters describing nerve thickening in compression and entrapment ulnar neuropathies at the elbow.

OBJECTIVE: To compare pattern and parameters describing nerve thickening in ulnar neuropathy at the elbow (UNE) due to external compression in the retrocondylar groove (RTC), and entrapment under the humeroulnar aponeurosis (HUA). METHODS: In a group of our previously reported UNE patients we ultrasonographically (US) measured ulnar nerve cross-sectional areas (CSA) on 6-8 standard locations in the elbow segment. We compared CSA patterns in both groups, and determined diagnostic utility of selected CSA based parameters. RESULTS: We studied 79 patients (81 arms) with UNE due to external compression, and 53 patients (55 arms) due to entrapment. Maximal ulnar nerve CSA (>16 mm2), maximal CSA change (>7 mm2/1-2 cm) and maximal/minimal CSA ratio (>2.6) were significantly larger in UNE due to entrapment. They also differentiated these arms from arms with compression with sensitivities of 78%, 87% and 80%, and specificities of 90%, 94%, and 85%, respectively. CONCLUSION: Maximal difference in CSA between points separated by 1-2 cm (>7 mm2/1-2 cm) very efficiently differentiated between UNE due to external compression and entrapment. SIGNIFICANCE: The proposed parameter will hopefully complement precise localization in determining underlying mechanism of UNE. This may help physicians to determine the most appropriate treatment for UNE and possibly other focal neuropathies of unknown cause; i.e., conservative treatment for external compression and surgery for entrapment.

Ulnar tunnel syndrome: pathoanatomy, clinical features and management.

Ulnar tunnel syndrome is compression of the ulnar nerve at the level of the wrist within Guyon's canal. It is most commonly caused by a ganglion cyst but may also be secondary to fractures, inflammatory conditions, neoplasm, vascular anomalies, aberrant musculature or a combination of these. Assessment should include a detailed history focusing on duration, site and progression of symptoms. The level of compression can be estimated clinically on examination by assessing motor and sensory changes in the hand. Investigations are used to confirm diagnosis or to clarify the underlying cause. X-rays and computed tomography can be used to exclude fractures. Ultrasound is used to diagnose ganglion cysts and vascular anomalies, and can localise the level of compression. Nerve conduction studies can be used to support the diagnosis and look for proximal compression. Mild symptoms can be managed non-operatively. Surgical exploration and decompression is the gold standard treatment for neuro-compressive causes with largely good outcomes.

An electrodiagnostic grading system for ulnar neuropathy at the elbow.

INTRODUCTION: Ulnar neuropathy at the elbow (UNE) is the second most common entrapment neuropathy. Our goal was to create and analyze a grading system for UNE electrodiagnostic severity. METHODS: We retrospectively analyzed EMG reports with UNE. We then classified 112 limbs as having mild, moderate, or severe grade UNE based on electrodiagnostic findings. The association between presenting symptoms and signs, EMG findings, treatment type, and electrodiagnostic grade was statistically analyzed. RESULTS: Seventeen limbs (15.2%) had mild, 80 (71.4%) had moderate, and 15 (13.4%) had severe UNE. Symptoms (P = .016), exam findings (P < .001), and treatment type (P = .043) were significantly associated with electrodiagnostic grade. DISCUSSION: Our UNE grading system was significantly related to symptoms, physical exam, and treatment selection and may be useful to measure electrodiagnostic severity.

Hypothenar Hammer Syndrome with Ulnar Nerve Neuropathy.

Hypothenar hammer syndrome is a rare medical condition that is usually associated with repetitive hand trauma. In this article, we delineate the importance of the nerve conduction velocity study to help determine objectively whether neuropathy is significant to the point that surgical means should be considered in absence of obvious ischemic change.

Efficacy of shortwave diathermy in ulnar nerve entrapment at the elbow: a double-blind randomized controlled clinical trial.

OBJECTIVE: To investigate the efficacy of shortwave diathermy in treatment of ulnar nerve entrapment at the elbow. DESIGN: The study was a double blind, randomized controlled clinical trial. SETTING, PARTICIPANTS: A total of 76 adult patients diagnosed with ulnar nerve entrapment at the elbow clinically and electrophysiologically, were randomly assigned into two groups. Patients were evaluated at baseline, after completing treatment and 1 and 3 months after treatment. Physical examination, quick-DASH (disabilities of arm, shoulder, hand) and SF-36 (short form) questionnaires for daily life activities, dynamometer for grip strength, and visual analog scale for pain were used. INTERVENTION: A total of 10 sessions of shortwave diathermy were applied to patients in treatment group as five sessions/week, 2 weeks. Control group was given placebo shortwave diathermy. Both groups were given elbow splints and informed to avoid symptom provoking activities. MAIN OUTCOME MEASURES: Visual analog scale, grip strength, SF-36, and quick-DASH results. RESULTS: Out of 76 patients, 61 of them completed the study where n = 31 for treatment group and n = 30 for control group. Mean age was 46.18 ± 13.45 years. There were 32 (52.5%) women and 29 (47.5%) men. The p values between groups 3 months after intervention for visual analog scale, quick-DASH, SF-36 questionnaire, and dynamometer were 0.669, 0.277, 0.604, and 0.126, respectively (p > 0.05). CONCLUSION: Application of shortwave diathermy to patients with ulnar nerve neuropathy at the elbow was not associated with any difference in outcome.

Unusual olecranon mass with ulnar nerve compressive neuropathy caused by a haemophilic pseudotumour.

A 55-year-old man with a history of haemophilia A and bilateral haemophilic arthropathy of the elbows presented with an enlarging left elbow mass and worsening paresthesias in the ulnar distribution of the left hand. The mass, originally thought to be olecranon bursitis and treated as such, was found to be due to a haemophilic pseudotumour. The patient underwent successful excision of the haemophilic pseudotumour with concomitant ulnar nerve decompression and had sustained resolution of the pseudotumour and symptoms at 10 years of follow-up. This case demonstrates the need for consideration of haemophilic pseudotumour in the differential diagnosis for olecranon masses and cubital tunnel compressive neuropathy in patients with haemophilia, and highlights the viability of surgical excision as a therapeutic option for the treatment of haemophilic pseudotumours in the elbow.

Performance and Return to Sport After Ulnar Nerve Decompression/Transposition Among Professional Baseball Players.

BACKGROUND: Isolated ulnar nerve decompression/transposition is an uncommon surgical procedure among professional baseball players. PURPOSE/HYPOTHESIS: To determine performance and rate of return to sport (RTS) among professional baseball players after isolated ulnar nerve decompression/transposition, including those who required decompression/transposition after ulnar collateral ligament reconstruction (UCLR), and to compare outcomes between cases and matched controls. The authors hypothesized a high rate of RTS among professional baseball players undergoing isolated ulnar nerve decompression/transposition with no difference in RTS rate or performance between cases and controls as related to earned run average, WHIP ([walks + hits]/innings pitched), wins above replacement, and on base + slugging percentage. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Utilizing the injury database of Major League Baseball, we identified all professional baseball players who underwent isolated ulnar nerve decompression/transposition between 2010 and 2016. De-identified demographic and performance data (before and after surgery) for each player were recorded from Major League Baseball records. Performance metrics were then compared between cases and matched controls. RESULTS: The study included 52 players; 83% were pitchers; and 14 underwent prior UCLR. Most surgical procedures (92%) were anterior subcutaneous transpositions. Overall, 62% of players were able to successfully RTS, and 56% returned to the same or higher level. There was no significant difference between cases and controls in the majority of pre- and postoperative performance metrics-specifically, earned run average, WHIP, wins above replacement, and on base + slugging percentage. When players who had UCLR before ulnar nerve decompression/transposition were compared with controls with a history of UCLR but no subsequent ulnar nerve decompression/transposition, the only performance difference of all the recorded metrics was that cases allowed more walks per 9 innings (4.4 vs 2.8, P = .011). CONCLUSION: Anterior subcutaneous transposition is the most common surgical procedure among professional baseball players to address ulnar neuropathy at the elbow. Players have a 62% rate of RTS, which is lower than expected for this nonreconstruction or repair procedure. For players who successfully RTS, performance metrics versus matched controls remained the same except for allowing significantly more walks per 9 innings. Postoperatively, pitchers with UCLR before ulnar nerve decompression/transposition who had a successful RTS performed the same as matched controls with prior UCLR without subsequent ulnar nerve decompression/transposition.

Patient Characteristics in Ulnar Nerve Compression at the Elbow at a Tertiary Referral Hospital and Predictive Factors for Outcomes of Simple Decompression versus Subcutaneous Transposition of the Ulnar Nerve.

Patient characteristics and predictive factors for outcomes were analysed in 202 cases undergoing simple decompression, primary subcutaneous transposition, or secondary subcutaneous transposition for ulnar nerve compression at the elbow at a tertiary referral hospital. Data from medical charts and a survey were evaluated. The mean patient age was 49 years with revision surgery cases being significantly younger. Sixty-one percent of cases were female, and 31% were smokers. The comorbidity was extensive, including other nerve compression lesions as well as neck and shoulder problems. Overall, 53% reported being pleased with the result of surgery and 57% of the cases rated function as better or completely recovered after surgery. The median postoperative DASH (Disabilities of the Arm, Shoulder and Hand) score was 26 (IQR 11-49), which is in accordance with unpublished national data. No significant differences in DASH scores were found between surgical groups, but a higher preoperative McGowan grade was significantly associated with a poorer postoperative DASH score. Women scored greater disability postoperatively than men. There was a significantly increased risk of complications, which was doubled for smokers, following primary and secondary transposition compared to simple decompression. Surgical cases with ulnar nerve compression treated at a tertiary referral hospital constitute a heterogeneous group with great comorbidity and frequent concomitant nerve compression lesions. We suggest simple decompression as the procedure of first choice. Transposition can be used in selected cases or when simple decompression fails. All patients should be strongly recommended to stop smoking considering the remarkably increased risk for complications among smokers.

Innervation of the anconeus epitrochlearis muscle: MRI and cadaveric studies.

Ulnar neuropathy at the cubital tunnel is common. However, a rare form of ulnar neuropathy here is due to compression from an accessory muscle, the anconeus epitrochlearis. Reports in the literature regarding the details of this muscle's innervation are vague, so the aim of the present study was to characterize this anatomy more clearly. This was a combined review of magnetic resonance imaging (MRI) from patients with an anconeus epitrochlearis and ulnar neuropathy and cadaveric dissections to characterize the innervation of this variant muscle. A review of 11 patients and three reports of ulnar neuropathy and an anconeus epitrochlearis in the literature revealed no MRI changes consistent with acute denervation of this muscle. However, in two cases, there were signs of chronic denervation of the muscle. Dissection of five cadavers revealed that the nerve supply to the anconeus epitrochlearis originated proximal to the medial epicondyle, traveled parallel to the ulnar nerve, terminated on the deep aspect of this muscle, and had a mean length of 60 mm. This clinicoanatomical study provides evidence that the innervation of the anconeus epitrochlearis is proximal to the muscle and on its deep aspect. Clin. Anat. 32:218-223, 2019. © 2018 Wiley Periodicals, Inc.

Development and validation of a new patient-reported outcome measure for peripheral nerve disorders of the hand, the I-HaND© Scale.

Following guidelines from the Patient-Centred Outcomes Research Institute and using a mixed methods study, a new patient-reported outcome measure (PROM) for both nerve trauma and compression affecting the hand, the Impact of a Hand Nerve Disorders (I-HaND) Scale, was developed. Face-to-face interviews with 14 patients and subsequent pilot-testing with 61 patients resulted in the development of the 32-item PROM. A longitudinal validation study with 82 patients assessed the psychometric properties of the I-HaND. Content and construct validity was confirmed by cognitive interviews with patients and through principal component analysis. The I-HaND has high internal consistency (α = 0.98) and excellent test-retest reliability (intraclass correlation coefficient = 0.97). Responsiveness statistics showed that the I-HaND can detect change over 3 months and discriminate between improvers and non-improvers. We conclude that the I-HaND can be used as a PROM for people with a range of hand nerve disorders.

Comparison of Ultrasonography and Short-Segment Nerve Conduction Study in Ulnar Neuropathy at the Elbow.

OBJECTIVE: To assess the correlation between ultrasonographic and electrodiagnostic findings to determine the localization of the ulnar trapping at the elbow. DESIGN: Cross-sectional and noninterventional trial. SETTING: Physical medicine and rehabilitation department of a teaching hospital. PARTICIPANTS: Patients (N=14) diagnosed with ulnar nerve entrapment using short-segment nerve conduction study. INTERVENTIONS: The elbow area was divided into 4 segments with 2-cm intervals. All patients underwent ultrasonographic and electrodiagnostic examinations. MAIN OUTCOME MEASURES: The nerve conduction velocity (NCV) of each segment was measured. The cross-sectional area (CSA) of the ulnar nerve was measured at 5 levels. The proximal CSA/distal CSA ratio (PDR) was calculated by proportioning the CSA values for each segment. The highest PDR was accepted as a trapping segment, whereas the segment with the lowest NCV was accepted electrophysiologically (provided it was <50m/s). RESULTS: A total of 80 PDR and NCV measurements were taken from 20 elbows. A statistically significant negative correlation (r=-.554; P<.001) was found between general PDR and NCV values. When we assumed that the NCV value <50m/s as the criterion standard for diagnosis, the cutoff value for the PDR was found to be 1.08, with a sensitivity of 70% and a specificity of 92.5%. The minimum NCV value and the maximum PDR value were mostly seen in the third segment compatible with the cubital tunnel. CONCLUSIONS: Ultrasonography seems to be advantageous because it is more comfortable for the patient and requires shorter time than does electroneuromyography. To our knowledge, this is the first study to detect ulnar nerve entrapment by using not only CSA but also PDR as a ratio method with ultrasound.

The cubital tunnel syndrome caused by the intraneural or extraneural ganglion cysts: Case report and review of the literature.

Cubital tunnel syndrome is the second most common nerve compression syndrome in peripheral nerve compression disease. Although potential ulnar nerve entrapment can occur at multiple points along its course, such as the arcade of struthers, the medial intermuscular septum, the medial epicondyle, the cubital tunnel, and the deep flexor pronator aponeurosis, the most common site of entrapment is the cubital tunnel. However, cubital tunnel syndrome could also be caused by the occupying masses along the course of ulnar nerve, such as intraneural or extraneural ganglia. The cubital tunnel syndrome caused by intraneural or extraneural ganglion cysts has been rarely reported. In our hospital, there were 184 patients with cubital tunnel syndrome who underwent surgical treatment from January 2010 to January 2014. Of these patients, 16 had extraneural cysts and 3 had intraneural ganglion cysts. The incidence rate of cysts in the cubital tunnel was 10.33%. Electromyography was used as routine examination. Ultrasound was used only in some patients in whom elbow mass was suspected. In the surgery of the cubital tunnel syndrome combined with cyst, if any other cysts were found, we should be remove completely the cyts and decompress the ulnar nerve thoroughly with the ulnar nerve being anterior transposition. These cysts were confirmed by histopathological examination. Finally, we compared the clinical features of patients who had a medial elbow ganglion with those of patients who had only cubital tunnel syndrome. B ultrasound can significantly improve the diagnosis. All patients were followed up for 4 months to 2 years, and the curative effect was good.

Is ulnar nerve entrapment at wrist frequent among patients with carpal tunnel syndrome occupationally exposed to monotype wrist movements?

OBJECTIVES: Association between carpal tunnel syndrome (CTS) and ulnar nerve entrapment at wrist remains controversial. The aim of the study has been to investigate the prevalence of Guyon's canal syndrome amongst patients diagnosed with the CTS, occupationally exposed to repetitive wrist movements. MATERIAL AND METHODS: The retrospective analysis of 310 patients (268 females, 42 males) representing the mean age of 52±7 years old hospitalized for the suspected occupational CTS was performed. RESULTS: In the analyzed cohort, 4 patients had undergone decompression of the Guyon's canal in the right limbs. Nerve conduction studies (NCS) in the ulnar nerves performed during the hospitalization of those patients did not show any abnormalities. Nerve conduction studies revealed signs of the ulnar neuropathy (UN) at the wrist affecting exclusively sensory fibers for 6 patients. Only those 4 patients who had undergone the operation suffered from clinical symptoms of the UN before the surgery. In the case of the remaining patients, despite the NCS changes, signs suggestive of the UN at the wrist were not detected. In the case of the patients with the occupational CTS, no signs of the ulnar nerve dysfunction were recorded. CONCLUSIONS: The frequency of ulnar nerve entrapment at the wrist among patients with the CTS is lower than that already reported. The low prevalence of ulnar involvement (3.2%) for the CTS patients in our study may be related to the relatively small number of the CTS hands with the severe changes in the NCS and/or other personal factor including anatomical variation of the Guyon's canal borders and its contents. Int J Occup Med Environ Health 2017;30(6):861-874.

Ultrasound biomechanical anatomy of the soft structures in relation to the ulnar nerve in the cubital tunnel of the elbow.

BACKGROUND: Chronic ulnar nerve entrapment worsened by elbow flexion is the most common injury, but rare painful conditions may also be related to ulnar nerve instability. The posterior bundle of the medial collateral ligament (pMCL) and the retinaculum, respectively form a soft floor and a ceiling for the cubital tunnel. The aim of our study was to dynamically assess these soft structures of the cubital tunnel focusing on those involved in the biomechanics of the ulnar nerve. METHODS: Forty healthy volunteers had a bilateral ultrasonography of the cubital tunnel. Elbows were scanned in full extension, 45° and 90°, and maximal passive flexion. Morphological changes of the nerve and related structures were dynamically assessed on transverse views. RESULTS: Both the pMCL and the retinaculum tightened with flexion. During elbow flexion, the tightening of the pMCL superficially moved the ulnar nerve remote from the osseous floor of the retroepicondylar groove. A retinaculum was visible in all 69 tunnels with stable nerves (86.3%), tightened in flexion, but absent in 11 tunnels with unstable nerves (13.7%). The retinaculum was fibrous in 60 elbows and muscular in nine, the nine muscular variants did not significantly influence the biomechanics of stable nerves. Stable nerves flattened in late flexion between the tightened pMCL and retinaculum, whereas unstable nerves transiently flattened when translating against the anterior osseous edge of the groove. CONCLUSION: The retinaculum and the pMCL are key structures in the biomechanics of the ulnar nerve in the cubital tunnel of the elbow.

Anconeus Epitrochlearis Muscle Causing Ulnar Neuropathy at the Elbow: Clinical and Neurophysiological Differential Diagnosis.

Ulnar neuropathy at the elbow is the second most frequent entrapment neuropathy and is considered idiopathic in most patients. However, several anatomic variations, including the anconeus epitrochlearis muscle, have been reported to cause ulnar nerve compression. The anconeus epitrochlearis muscle is a common anatomic variation, with a prevalence of up to 34%, but the clinical diagnosis of ulnar neuropathy of the elbow as a result of this variation is rare, with an unknown prevalence. It is a congenital accessory muscle between the medial humeral epicondyle and the olecranon that covers the posterior aspect of the cubital tunnel and is usually an operative finding, not a preoperative diagnosis. Ulnar neuropathy as a result of the anconeus epitrochlearis muscle usually has different characteristics than idiopathic disease, including younger age at onset, more rapid progression with a short duration of symptoms, distinct neurophysiology with velocity drop or conduction block of the ulnar nerve, and edema of the anconeus epitrochlearis muscle on magnetic resonance imaging. Neurophysiologic findings in anconeus epitrochlearis-associated ulnar neuropathy indicate subacute onset of symptoms rather than the chronic demyelinating process that is seen in idiopathic ulnar neuropathy. Medial elbow pain may be more exacerbated in these patients rather than the more common sensorial symptoms. This is probably the result of static compression of the nerve and increased cubital tunnel pressure, even when the elbow is in extension. This article describes a case of ulnar nerve entrapment of the elbow in a 28-year-old woman as a result of compression by the anconeus epitrochlearis muscle and includes magnetic resonance imaging findings, surgical correlations, and clinical and neurophysiologic findings. [Orthopedics. 2016; 39(5):e988-e991.].

Altered ulnar nerve kinematic behavior in a cadaver model of entrapment.

BACKGROUND: Ulnar nerve entrapment at the elbow is more than a compressive lesion of the nerve. The tensile biomechanical consequences of entrapment are currently marginally understood. OBJECTIVE: To evaluate the effects of tethering on the kinematics of the ulnar nerve as a model of entrapment neuropathy. METHODS: The ulnar nerve was exposed in 7 fresh cadaver arms, and markers were placed at 1-cm increments along the nerve, centered on the retrocondylar region. Baseline translation (pure sliding) and strain (stretch) were measured in response to progressively increasing tension produced by varying configurations of elbow flexion and wrist extension. Then the nerves were tethered by suturing to the cubital tunnel retinaculum and again exposed to progressively increasing tension from joint positioning. RESULTS: In the native condition, for all joint configurations, the articular segment of the ulnar nerve exhibited greater strain than segments proximal and distal to the elbow, with a maximum strain of 28 ± 1% and translation of 11.6 ± 1.8 mm distally. Tethering the ulnar nerve suppressed translation, and the distal segment experienced strains that were more than 50% greater than its maximum strain in an untethered state. CONCLUSION: This work provides a framework for evaluating regional nerve kinematics. Suppressed translation due to tethering shifted the location of high strain from articular to more distal regions of the ulnar nerve. The authors hypothesize that deformation is thus shifted to a region of the nerve less accustomed to high strains, thereby contributing to the development of ulnar neuropathy.

Ulnar nerve compression at the wrist: diagnostic role of palmar stimulation.

OBJECTIVE: Electrophysiological diagnosis of ulnar nerve entrapment at the wrist is sometimes difficult. The aim was to evaluate the diagnostic role of ulnar nerve stimulation above and below the Guyon channel in ulnar nerve entrapment at the wrist. METHODS: Supramaximal ulnar nerve stimulation at the wrist and palm, in addition to the standard nerve conduction studies, in 10 patients with ulnar nerve entrapment at the wrist and 40 controls. RESULTS: Motor latencies to the first dorsal interosseous muscle with wrist stimulation were prolonged unilaterally in six and bilaterally in four patients. Palmar stimulation showed partial conduction blocks on the more symptomatic side in all. In two bilateral cases, there were 28.8% and 44.3% amplitude loss on the less symptomatic side. Motor responses elicited with palm stimulation were also found to have prolonged latencies and decreased amplitudes. CONCLUSIONS: Stimulation of the deep branch of the ulnar nerve can expand the information about ulnar nerve entrapment at the wrist by providing evidence about its nature, prognosis, precise localization, and distal extent.

Velocity drop in anconeus epitrochlearis-associated cubital tunnel syndrome.

The anconeus epitrochlearis (AE) muscle is a common anatomical variation in the cubital tunnel retinaculum of the elbow with an incidence of up to 28%; it is one cause of compressive ulnar neuropathy. In this study, we report the significance of preoperative recognition of AE-associated cubital tunnel syndrome, based on the grade of velocity drop of the compressed ulnar nerve in electrophysiological studies. Twenty-two cases with idiopathic cubital tunnel compression (CTC) were retrospectively analyzed; AE was present in 6 cases. Velocity drop of the ulnar nerve was calculated by dividing the difference in velocity (m/s) by distance (cm); the results were classified into the following grades: + (0-2.99 m/s per cm) and ++ (< 3.00 m/s per cm). Categorical data were compared using Fisher's exact test; the Mann-Whitney U test was used to determine statistical significance of ordinal data. In patients with AE-associated CTC, 3 of the 6 (50%) cases had grade ++ velocity drop. In comparison, only 1 patient of the 16 non-AE cases (6%) had grade ++ velocity drop (P = .046). Preoperative nerve velocity conduction studies that show grade ++ velocity drop (< 3.00 m/s per cm) in ulnar nerve are highly suggestive of the presence of AE.