Predictors of Functional Outcome Change 18 Months After Anterior Ulnar Nerve Transposition

Anterior Interosseus to Ulnar Motor Nerve Transfers: A Canadian Perspective

BACKGROUND

The anterior interosseus nerve (AIN) to ulnar motor nerve transfer has been popularized as an adjunct to surgical decompression in patients with severe cubital tunnel syndrome (CuTS) and high ulnar nerve injuries. The factors influencing its implementation in Canada have yet to be described.

METHODS

An electronic survey was distributed to all members of the Canadian Society of Plastic Surgery (CSPS) using REDCap software. The survey examined 4 themes: previous training/experience, practice volume of nerve pathologies, experience with nerve transfers, and approach to the treatment of CuTS and high ulnar nerve injuries.

RESULTS

A total of 49 responses were collected (12% response rate). Of all, 62% of surgeons would use an AIN to ulnar motor supercharge end-to-side (SETS) transfer for a high ulnar nerve injury. For patients with CuTS and signs of intrinsic atrophy, 75% of surgeons would add an AIN-SETS transfer to a cubital tunnel decompression. Sixty-five percent would also release Guyon's canal, and the majority (56%) use a perineurial window for their end-to-side repair. Eighteen percent of surgeons did not believe the transfer would improve outcomes, 3% cited lack of training, and 3% would preferentially use tendon transfers. Surgeons with hand fellowship training and those less than 30 years in practice were more likely to use nerve transfers in the treatment of CuTS (P < .05).

CONCLUSIONS

Most CSPS members would use an AIN-SETS transfer in the treatment of both a high ulnar nerve injury and severe CuTS with intrinsic atrophy.

Electrodiagnostic severity does not predict short- to midterm outcomes of cubital tunnel release surgery

HYPOTHESIS

This study aimed to explore the prognostic value of electrodiagnostic studies (EDS) to clarify their utility in clinical practice prior to cubital tunnel release surgery and to identify patient factors associated with patient-reported functional improvement after surgery. Our hypothesis was that patients with severe preoperative findings on EDS will tend to experience less functional improvement after surgery given the extent of ulnar nerve compressive injury.

METHODS

Patients with cubital tunnel syndrome and preoperative electrodiagnostic data treated from 2012 to 2022 with cubital tunnel release were assessed regarding demographic information, preoperative physical examination findings, EDS findings, postoperative complications, and patient-reported outcomes. Short- to midterm quick Disabilities of the Arm, Shoulder, and Hand questionnaire (qDASH) scores were collected for all patients for further evaluation of preoperative EDS data. Patients were grouped into those who had met the minimal clinically important difference (MCID) in delta qDASH at short- to midterm follow-up and those who did not. EDS data included sensory nerve onset latency, peak latency, amplitude, conduction velocity, as well as motor nerve latency, velocity, and amplitude. Electromyographic (EMG) studies were also reviewed, which included data pertaining to fibrillations, presence of abnormal fasciculation, positive sharp waves, variation in insertional activity, motor unit activity, duration of activity, and presence of increasing polymorphisms.

RESULTS

Of the 257 patients included, 160 (62.0%) were found to meet the MCID for short- to midterm qDASH scores. There were no significant differences between patients who did or did not meet the MCID regarding baseline demographics, comorbidities, preoperative examination findings, and operative technique. Patients who met MCID tended to have lower complication (3.80% vs. 7.20%, P = .248) and revision (0.60% vs. 4.10%, P = .069) rates, but these findings were not statistically significant. The cubital tunnel severity as determined by the EDS was similar between cohorts (14.1% vs. 14.3%, P = .498). Analysis of EMG testing showed there were no significant differences in preoperative, short- to midterm qDASH, or delta short- to midterm qDASH scores for patients with or without abnormal EMG findings. Multivariate regression suggested that only age (P = .003) was associated with larger delta qDASH scores.

CONCLUSION

Patient-reported preoperative disease severity may predict the expected postoperative change in ulnar nerve functional improvement, and EDS may not have prognostic value for patients undergoing cubital tunnel decompression. Therefore, physicians may suggest surgical treatment without positive EDS findings and still expect postoperative improvement in functional outcomes.

The Unpredictable Ulnar Nerve-Ulnar Nerve Entrapment from Anatomical, Pathophysiological, and Biopsychosocial Aspects

Peripheral nerves consist of delicate structures, including a rich microvascular system, that protect and nourish axons and associated Schwann cells. Nerves are sensitive to internal and external trauma, such as compression and stretching. Ulnar nerve entrapment, the second most prevalent nerve entrapment disorder after carpal tunnel syndrome, appears frequently at the elbow. Although often idiopathic, known risk factors, including obesity, smoking, diabetes, and vibration exposure, occur. It exists in all adult ages (mean age 40-50 years), but seldom affects individuals in their adolescence or younger. The patient population is heterogeneous with great co-morbidity, including other nerve entrapment disorders. Typical early symptoms are paresthesia and numbness in the ulnar fingers, followed by decreased sensory function and muscle weakness. Pre- and postoperative neuropathic pain is relatively common, independent of other symptom severity, with a risk for serious consequences. A multimodal treatment strategy is necessary. Mild to moderate symptoms are usually treated conservatively, while surgery is an option when conservative treatment fails or in severe cases. The decision to perform surgery might be difficult, and the outcome is unpredictable with the risk of complications. There is no consensus on the choice of surgical method, but simple decompression is relatively effective with a lower complication rate than transposition.

Preoperative electrodiagnostic studies and postoperative outcomes for ulnar mononeuropathy at the elbow: A systematic review

OBJECTIVE

To analyze the association between preoperative electrodiagnostic (EDX) studies and postoperative pain and functional outcomes following ulnar nerve decompression and/or transposition for ulnar neuropathy at the elbow (UNE).

LITERATURE SURVEY

Protocol was submitted and database search was conducted by an experienced librarian of all available studies in the English language from 1990 to June 8, 2022. Databases included Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, and Scopus.

METHODOLOGY

Inclusion criteria consisted of randomized controlled trials, prospective and retrospective longitudinal studies, and studies involving adults ≥18 years of age who underwent ulnar nerve decompression and/or transposition for UNE. Study quality and risk of bias were assessed using the National Heart, Lung, and Blood Institute (NHLBI) Study Quality of Assessment Tool. Certainty in evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. A meta-analysis was not performed.

SYNTHESIS

A total of 289 studies were screened, and 8 retrospective cohort studies met inclusion criteria comprising 762 patients. A decreased or absent preoperative sensory nerve action potential amplitude (SNAP) showed significance with worse postoperative outcomes. The presence of preoperative conduction block showed significance in higher quality studies. There was limited evidence for slow preoperative motor conduction velocities or preoperative electromyography (EMG) abnormalities and postoperative outcomes. Overall quality assessment demonstrated that two studies had "good," four "fair," and two "poor" quality of evidence. Certainty in evidence was "low" due to risk of bias.

CONCLUSIONS

A decreased or absent preoperative ulnar SNAP may predict worse postoperative outcomes. Per higher quality studies, preoperative conduction block at the elbow may also predict worse postoperative outcomes. Careful interpretation is required with a full understanding of the limited evidence, risk of bias, and low certainty in evidence to support the use of preoperative EDX to predict postoperative outcomes in UNE.

Sex differences in neuromuscular disorders

The prevalence, onset, pathophysiology, and clinical course of many neuromuscular disorders (NMDs) may significantly differ between males and females. Some NMDs are more frequently observed in females, and characterized to show a higher grade of severity during or after the pregnancy. Meanwhile, others tend to have an earlier onset in males and exhibit a more variable progression. Prevalently, sex differences in NMDs have a familiar character given from genetic inheritance. However, they may also influence clinical presentation and disease severity of acquired NMD forms, and are represented by both hormonal and genetic factors. Consequently, to shed light on the distinctive role of biological factors in the different clinical phenotypes, we summarize in this review the sex related differences and their distinctive biological roles emerging from the current literature in both acquired and inherited NMDs.

Quality of life and satisfaction in patients surgically treated for cubital tunnel syndrome

OBJECTIVE

Cubital tunnel syndrome (CuTS) results from compression of the ulnar nerve at the elbow, resulting in pain, weakness, and numbness of the hand and forearm. This work describes the Quality of Life (QoL) and satisfaction after CuTS surgery and identifies the factors associated with those outcomes.

METHODS

This cross-sectional study included patients surgically treated for CuTS from January 2011 to September 2021 at the Neurosurgery Clinic of the Clinic Center in Serbia. The questionnaires applied were the Short Form 36 (SF-36), EuroQol instrument (EQ-5D-5 L), Bishop's score and Patient-Rated Ulnar Nerve Evaluation (PRUNE).

RESULTS

Sixty-two patients met the inclusion criteria. Bishop's score: The median score was 10 (7.75-11), 54.8% of the cases presented excellent results. PRUNE: The median score for symptoms was 19 (6-38.5); for functional, was 14 (0.75-38); and the total was 18.25 (5.87-34.12). SF-36: The subscale with the best result was social functioning (84.68 ± 22.79). The scale with the worst value was emotional well-being (49.35 ± 7.87). EQ-5D-5L: Over 50% patients did not present problems with mobility, self-care, activity, and anxiety. The average EQ-VAS was 72.77 ± 18.70; and 0.72 ± 0.21 of the EQ-index, revealing a good QoL. Models for QoL and satisfaction: Ten models showed statistical significance. The variables with major involvement were body mass index and time evolution of the symptoms.

CONCLUSION

Surgical decompression has proved to diminish the symptoms, improving QoL and satisfaction. Many fixed and changeable factors can affect the satisfaction levels after surgery.

Electrodiagnostic Predictors of Outcomes After In Situ Decompression of the Ulnar Nerve

PURPOSE

Patients with severe ulnar neuropathy at the elbow frequently experience suboptimal surgical outcomes. Clinical symptoms alone may not accurately represent the severity of underlying nerve injury, calling for objective assessment tools, such as electrodiagnostic studies. The goal of our study was to determine whether specific electrodiagnostic parameters can be used to predict the outcomes after in situ decompression of the ulnar nerve.

METHODS

This prospective study enrolled consecutive patients aged ≥18 years diagnosed with ulnar neuropathy at the elbow. Patients completed a baseline battery of motor, sensory, functional, and electrodiagnostic tests before undergoing in situ decompression of the ulnar nerve. They were reassessed at 6 weeks, 3 months, 6 months, and 12 months after surgery. Forty-two patients completed at least 2 follow-up assessments and were included in the study.

RESULTS

When controlling for other electrodiagnostic measurements and demographic factors, none of the electrodiagnostic parameters were predictive of outcomes at 12 months after surgery. Patients with decreased compound muscle action potential amplitudes demonstrated slower trends of recovery in grip strength, pinch strength, and overall scores on the Michigan Hand Outcomes Questionnaire as well as its function, work, and activities of daily living subscales, Disabilities of the Arm, Shoulder, and Hand questionnaire, and the Carpal Tunnel Questionnaire. Decreased motor nerve conduction velocity was predictive of slower recovery of 2-point discrimination and pinch strength.

CONCLUSIONS

Compound muscle action potential amplitude, but not other conventional electrodiagnostic parameters, was predictive of functional outcomes after in situ decompression of the ulnar nerve. This parameter should play a role in determining the timing and prognosis of treatment for ulnar neuropathy at the elbow.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Socioeconomic Differences between Sexes in Surgically Treated Carpal Tunnel Syndrome and Ulnar Nerve Entrapment

We aimed to investigate socioeconomic differences between sexes and the influence on outcome following surgery for carpal tunnel syndrome (CTS) or ulnar nerve entrapment (UNE) at the elbow. Patients with CTS (n = 9000) or UNE (n = 1266) registered in the Swedish National Register for Hand Surgery (HAKIR) 2010-2016 were included and evaluated using QuickDASH 12 months postoperatively. Statistics Sweden (SCB) provided socioeconomic data. In women with CTS, being born outside Sweden, having received social assistance, and more sick leave days predicted worse outcomes. Higher earnings and the highest level of education predicted better outcomes. In men with CTS, more sick leave days and having received social assistance predicted worse outcomes. Higher earnings predicted better outcomes. For women with UNE, higher earnings predicted better outcomes. In men with UNE, only sick leave days predicted worse outcomes. In long-term follow up, socioeconomic status affects outcomes differently in women and men with CTS or UNE.

Reliability and validity of the modified McGowan grade in patients with cubital tunnel syndrome

INTRODUCTION

This study aimed to assess the reliability and validity of the modified McGowan grading system and to determine its ability to distinguish the severity of cubital tunnel syndrome (CuTS) between the different grades.

MATERIALS AND METHODS

We prospectively enrolled 39 consecutive patients with CuTS from March 2018 to December 2020. Inter- and intra-observer reliability was assessed by two orthopaedic surgeons with a minimum 2-week interval using Cohen kappa coefficients. Validity was assessed by Spearman's correlation with objective clinical outcomes (grip strength, Semmes-Weinstein monofilament test [SWMT], static two-point discrimination [2PD], and motor conduction velocity [MCV]). In addition, the relationship between the grading system and patient-reported outcomes (Disabilities of the Arm, Shoulder and Hand score and Boston Questionnaire) was evaluated using Spearman's correlation. The ability to distinguish the severity between the different grades was assessed using the Kruskal-Wallis analysis.

RESULTS

The inter-observer kappa value was 0.54 and intra-observer kappa value was 0.59, which imply a moderate reliability. The modified McGowan grade had a moderate correlation with objective clinical outcomes (grip strength [r = - 0.350, p = 0.029], SWMT [r = 0.552, p < 0.001], 2PD [r = 0.456, p = 0.004], and MCV [r = - 0.394, p = 0.021]). However, patient-reported outcomes did not correlate with this grading system. Kruskal-Wallis analysis revealed significant differences between grades in terms of SWMT, 2PD, grip strength, and Boston Questionnaire functional score (p = 0.006, 0.025, 0.014, and 0.043, respectively); however, these differences were statistically significant only for a limited number of parts.

CONCLUSIONS

The modified McGowan grade has a moderate inter- and intra-observer reliability. This grading system moderately correlates with objective sensory-motor functions and MCV of patients with CuTS. However, the modified McGowan grade does not reflect the patient's perceived disabilities and has a weakness in distinguishing the severity of patients' conditions among the different grades.

Submuscular transposition of the ulnar nerve for persistent or recurrent cubital tunnel syndrome: Results of a prospective case series

BACKGROUND

Submuscular transposition (SMT) of the ulnar nerve is frequently performed as secondary procedure in patients with persistent or recurrent cubital tunnel syndrome (CuTS) despite previous surgery. Good results have been reported for this surgical strategy, but mainly in small retrospective case series. The goal of the present study is therefore to analyze the results prospectively using a patient-reported outcome measure (PROM): patient-rated ulnar nerve evaluation (PRUNE).

METHODS

SMT of the ulnar nerve was performed in 30 consecutive patients who were referred because of persistent or recurrent CuTS despite previous surgery. Objective outcome was measured in the outpatient clinic using the Likert scale. The PRUNE questionnaire was obtained pre-operatively, 6 weeks, 3 months, 6 months, and 12 months after the surgery. Simultaneously, 20 patients with primary surgery for CuTS, that underwent simple decompression, were followed.

RESULTS

Good outcome (Likert 1 or 2) was obtained in 67% after SMT for persistent/recurrent CuTS and 85% after decompression as primary surgical treatment. PRUNE scores were significantly decreased in both groups at all follow-up moments after surgery compared with pre-operative for the total questionnaire and subscales "pain," "sensory/motor symptoms," and "specific activities." In both groups, PRUNE score remained stable until 12 months of follow-up.

CONCLUSION

This prospective study confirms previous results from retrospective studies showing that SMT is an effective surgical option for persistent or recurrent CuTS. Prospective (randomized controlled) trials are needed to compare the effectiveness of SMT to the surgical alternative of subcutaneous transposition of the ulnar nerve.

Preoperative Electrophysiology in Patients With Ulnar Nerve Entrapment at the Elbow-Prediction of Surgical Outcome and Influence of Age, Sex and Diabetes

The impact of preoperative electrophysiology on outcome of surgical treatment in ulnar nerve entrapment at the elbow (UNE) is not clarified. Our aim was to evaluate influence of preoperative electrophysiologic grading on outcome and analyse how age, sex, and in particular diabetes affect such grading. Electrophysiologic protocols for 406 UNE cases, surgically treated at two hand surgery units reporting to the Swedish National Quality Register for Hand Surgery (HAKIR; 2010-2016), were retrospectively assessed, and graded as normal, reduced conduction velocity, conduction block or axonal degeneration. Outcome of surgery after primary and revision surgery was evaluated using QuickDASH and a doctor reported outcome measure (DROM) grading. No differences in QuickDASH or DROM were found between the four groups with different electrophysiologic grading preoperatively, or at three and 12 months or at follow up, respectively. When dichotomizing the electrophysiologic grading into normal and pathologic electrophysiology, cases with normal electrophysiology had worse QuickDASH than cases with pathologic electrophysiology preoperatively (p=0.046). Presence of a conduction block or axonal degeneration indicated a worse outcome by DROM grading (p=0.011). Primary surgeries had electrophysiologic more pronounced nerve pathology compared to revision surgeries (p=0.017). Cases of older age, men, and those with diabetes had more severe electrophysiologic nerve affection (p&lt;0.0001). In the linear regression analysis, increasing age (unstandardized B=0.03, 95% CI 0.02-0.04; p&lt;0.0001) and presence of diabetes (unstandardized B=0.60, 95% CI 0.25-0.95; p=0.001) were associated with a higher risk of a worse electrophysiologic classification. Female sex was associated with a better electrophysiologic grading (unstandardized B=-0.51, 95% CI -0.75- -0.27; p&lt;0.0001). We conclude that older age, male sex, and concomitant diabetes are associated with more severe preoperative electrophysiologic nerve affection. Preoperative electrophysiologic grade of ulnar nerve affection may influence surgical outcome.

Cubital tunnel syndrome

Cubital tunnel syndrome (CuTS) is the second most common compression neuropathy of the upper limb, presenting with disturbance of ulnar nerve sensory and motor function.The ulnar nerve may be dynamically compressed during movement, statically compressed due to reduction in tunnel volume or compliance, and tension forces may cause ischaemia or render the nerve susceptible to subluxation, further causing local swelling, compression inflammation and fibrosis.Superiority of one surgical technique for the management of CuTS has not been demonstrated. Different techniques are selected for different clinical situations with simple decompression being the most common procedure due to its efficacy and low complication rate.Adjunctive distal nerve transfer for denervated muscles using an expendable motor nerve to restore the axon population in the distal nerve is in its infancy but may provide a solution for severe intrinsic weakness or paralysis. Cite this article: EFORT Open Rev 2021;6:743-750. DOI: 10.1302/2058-5241.6.200129.

MRI of the ulnar nerve pre- and post-transposition: imaging features and rater agreement

OBJECTIVE

Determine the rater agreement of MRI features of the ulnar nerve pre- and post-transposition and association with recurrent symptoms.

MATERIALS AND METHODS

This IRB-approved retrospective cohort analysis examined 23 subjects who underwent elbow MRI pre- and post-ulnar nerve transposition from 1999 to 2018, 10 of whom developed recurrent symptoms. Pre- and post-transposition MRIs were evaluated by two blinded radiologists for ulnar nerve cross-sectional area, signal intensity, fascicular architecture, caliber change, and perineural scar. Inter-rater agreement was estimated using intraclass correlation coefficients (ICCs) for continuous variables and Gwet's agreement coefficient (AC) for categorical variables. Binary logistic regression modeling probed associations between imaging markers and symptom recurrence.

RESULTS

The ulnar nerve, post-operatively, demonstrated statistically significant increases in size (p < 0.001), signal intensity (p = 0.021), and abrupt caliber change (p = 0.024). None of the imaging features, except for higher signal intensity of the nerve pre-transposition as demonstrated by one rater, were predictive of symptom recurrence. Inter-rater agreement for cross-sectional area measurements of the ulnar nerve at the cubital tunnel was excellent (ICCs of 0.91 and 0.83). Substantial-to-excellent inter-rater agreement was observed pre-operatively for nerve signal intensity, caliber change, and fascicular architecture. Post-operatively, agreement on nerve signal intensity and perineural scar was excellent (ACs of 0.90 and 0.88), but only slight for caliber change (0.15).

CONCLUSION

Inter-rater agreement for qualitative and quantitative assessment of the ulnar nerve was generally robust. Post-transposition, the ulnar nerve was generally larger and more T2-hyperintense, but MRI features were not predictive of recurrent ulnar neuropathy, except for perhaps the signal intensity of the nerve pre-transposition.

Supercharge End-to-Side Anterior Interosseous-to-Ulnar Motor Nerve Transfer Restores Intrinsic Function in Cubital Tunnel Syndrome

BACKGROUND

The supercharge end-to-side anterior interosseous nerve-to-ulnar motor nerve transfer offers a viable option to enhance recovery of intrinsic function following ulnar nerve injury. However, in the setting of chronic ulnar nerve compression where the timing of onset of axonal loss is unclear, there is a deficit in the literature on outcomes after supercharge end-to-side anterior interosseous nerve-to-ulnar motor nerve transfer.

METHODS

A retrospective study of patients who underwent supercharge end-to-side anterior interosseous nerve-to-ulnar motor nerve transfer for severe cubital tunnel syndrome over a 5-year period was performed. The primary outcomes were improvement in first dorsal interosseous Medical Research Council grade at final follow-up and time to reinnervation. Change in key pinch strength; grip strength; and Disabilities of the Arm, Shoulder and Hand questionnaire scores were also evaluated using paired t tests and Wilcoxon signed rank tests.

RESULTS

Forty-two patients with severe cubital tunnel syndrome were included in this study. Other than age, there were no significant clinical or diagnostic variables that were predictive of failure. There was no threshold of compound muscle action potential amplitude below which supercharge end-to-side anterior interosseous nerve-to-ulnar motor nerve transfer was unsuccessful.

CONCLUSIONS

This study provides the first cohort of outcomes following supercharge end-to-side anterior interosseous nerve-to-ulnar motor nerve transfer in chronic ulnar compression neuropathy alone and underscores the importance of appropriate patient selection. Prospective cohort studies and randomized controlled trials with standardized outcome measures are required.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Reverse End-to-Side Anterior Interosseous Nerve-to-Ulnar Motor Transfer for Severe Ulnar Neuropathy

BACKGROUND

Reverse end-to-side anterior interosseous nerve transfer has been reported to enhance treatment of severe, proximal ulnar neuropathy. The authors report on patients with severe neuropathy treated with ulnar nerve transposition and distal reverse end-to-side anterior interosseous nerve transfer.

METHODS

Thirty patients with severe ulnar neuropathy at the elbow were reviewed. Clinical parameters included preoperative and postoperative Medical Research Council muscle strength, clawing, and degree of wasting. Electrodiagnostic data included compound motor action potential and sensory nerve action potential amplitudes. Summary statistics were used for demographic and clinical data. The t test and Wilcoxon signed rank test were used where appropriate.

RESULTS

Average follow-up was 18.6 months. Preoperatively, 20 patients had Medical Research Council less than or equal to grade 1 in hand intrinsics, small finger sensory nerve action potentials were absent in all patients except for three, and average compound motor action potentials were severely reduced (absent in nearly 40 percent) confirming severity. All groups had a statistically significant increase in strength. More than three-quarters of patients noted partial or complete resolution of clawing and intrinsic muscle wasting. Seventy-three percent of patients regained Medical Research Council greater than or equal to grade 3 and 47 percent achieved Medical Research Council greater than or equal to grade 4. Mean time to observation of nascent units was 8.5 months, and 77 percent of patients demonstrated an augmentation of motor unit numbers with forearm pronation on needle electromyography CONCLUSION:: Proximal subcutaneous ulnar nerve transposition when combined with reverse end-to-side anterior interosseous nerve-to-ulnar nerve transfer demonstrates significant clinical and electrodiagnostic improvement of intrinsic muscle function.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Reporting Outcomes and Outcome Measures in Cubital Tunnel Syndrome: A Systematic Review

PURPOSE

Comparison between studies assessing outcomes after surgical treatment of cubital tunnel syndrome (CuTS) has proven to be difficult owing to variations in outcome reporting. This study aimed to identify outcomes and outcome measures used to evaluate postoperative results for CuTS.

METHODS

We performed computerized database searches of MEDLINE and EMBASE. Studies with 20 or more patients aged 18 and older who were undergoing medial epicondylectomy, endoscopic decompression, open simple decompression, or decompression with subcutaneous, submuscular, or intramuscular transposition for ulnar neuropathy at the elbow were included. Outcomes and outcome measures were extracted and tabulated.

RESULTS

Of the 101 studies included, 45 unique outcomes and 31 postoperative outcome measures were identified. These included 7 condition-specific, clinician-reported instruments; 4 condition-specific, clinician-reported instruments; 8 patient-reported, generic instruments; 11 clinician-generated instruments; and one utility measure. Outcome measures were divided into 6 unique domains. Overall, 60% of studies used condition-specific outcome measures. The frequency of any condition-specific outcome measure ranged from 1% to 37% of included studies.

CONCLUSIONS

There is marked heterogeneity in outcomes and outcome measures used to assess CuTS. A standardized core outcome set is needed to compare results of various techniques of cubital tunnel decompression.

CLINICAL RELEVANCE

This study builds on the existing literature to support the notion that there is marked heterogeneity in outcomes and outcome measures used to assess CuTS. The authors believe that a future standardized set of core outcomes is needed to limit heterogeneity among studies assessing postoperative outcomes in CuTS to compare these interventions more easily and pool results in the form of systematic reviews and meta-analyses.

Associations Between Insurance Type and the Presentation of Cubital Tunnel Syndrome

PURPOSE

In the setting of cubital tunnel syndrome (CuTS), delays in diagnosis can have permanent effects including sensory loss, muscle weakness, and atrophy of intrinsic hand muscles. This study sought to evaluate the association of insurance type on the severity of CuTS. We hypothesized that publicly insured patients will have delayed presentation to the orthopedics office and more significant condition severity.

METHODS

A retrospective chart review was conducted for all patients evaluated for CuTS between December 2013 and January 2018 by a fellowship-trained orthopedic hand and upper extremity surgeon at our tertiary referral center. Insurance type, demographics, and measures of CuTS severity were compared.

RESULTS

Patients presenting with CuTS of severity greater than or equal to McGowan stage 2A had 4.4-fold greater odds of being publicly insured than privately. Motor and sensory velocities across the elbow were diminished at 42.2 ± 13.9m/s and 33.0 ± 20.8m/s in publicly insured patients compared with 47.5 ± 11.3 m/s and 47.0 ± 16.4m/s for privately insured patients. The same trend was present for motor and sensory amplitudes at 6.6 ± 3.8 μV and 16.9 ± 17.8 μV in publicly insured patients compared with 8.5 ± 3.2 μV and 26.0 ± 18.9 μV in privately insured patients. Patients with public insurance were symptomatic for longer prior to their initial visit, on average 82.8 ± 86.5 weeks, compared with 42.4 ± 58.9 weeks for patients with private insurance.

CONCLUSIONS

Publicly insured patients were significantly delayed in seeing an orthopedic surgeon for evaluation and treatment of CuTS and presented with more severe clinical and electrodiagnostic findings compared with privately insured patients. These findings suggest that insurance type, among other socioeconomic factors, may be a barrier to CuTS care.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prevalence IV.

Compound Muscle Action Potential Amplitude Predicts the Severity of Cubital Tunnel Syndrome

BACKGROUND

Cubital tunnel syndrome has a spectrum of presentations ranging from mild paresthesias to debilitating numbness and intrinsic atrophy. Commonly, the classification of severity relies on clinical symptoms and slowing of conduction velocity across the elbow. However, changes in compound muscle action potential (CMAP) amplitude more accurately reflect axonal loss. We hypothesized that CMAP amplitude would better predict functional impairment than conduction velocity alone.

METHODS

A retrospective cohort of patients who underwent a surgical procedure for cubital tunnel syndrome over a 5-year period were included in the study. All patients had electrodiagnostic testing performed at our institution. Clinical and electrodiagnostic variables were recorded. The primary outcome was preoperative functional impairment, defined by grip and key pinch strength ratios. Multivariable regression identified which clinical and electrodiagnostic variables predicted preoperative functional impairment.

RESULTS

Eighty-three patients with a mean age of 57 years (75% male) were included in the study. The majority of patients (88%) had abnormal electrodiagnostic studies. Fifty-four percent had reduced CMAP amplitude, and 79% had slowing of conduction velocity across the elbow (recorded from the first dorsal interosseous). On bivariate analysis, older age and longer symptom duration were significantly associated (p < 0.05) with reduced CMAP amplitude and slowing of conduction velocity across the elbow, whereas body mass index (BMI), laterality, a primary surgical procedure compared with revision surgical procedure, Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire scores, and visual analog scale (VAS) scores for pain were not. Multivariable regression analysis demonstrated that reduced first dorsal interosseous CMAP amplitude independently predicted the loss of preoperative grip and key pinch strength and that slowed conduction velocity across the elbow did not.

CONCLUSIONS

Reduced first dorsal interosseous amplitude predicted preoperative weakness in grip and key pinch strength, and isolated slowing of conduction velocity across the elbow did not. CMAP amplitude is a sensitive indicator of axonal loss and an important marker of the severity of cubital tunnel syndrome. It should be considered when counseling patients with regard to their prognosis and determining the necessity and timing of operative intervention.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Comparison of Surgical Encounter Direct Costs for Three Methods of Cubital Tunnel Decompression

BACKGROUND

In situ decompression, subcutaneous transposition, and submuscular transposition for cubital tunnel syndrome have historically yielded similar outcomes. The authors' null hypothesis is that no differences exist in surgical encounter total direct costs for in situ decompression, subcutaneous transposition, and submuscular transposition.

METHODS

Adult patients treated surgically for cubital tunnel syndrome by four fellowship-trained hand surgeons between August of 2011 and December of 2016 were identified by CPT code (64718) at their tertiary academic institution. Patients with prior elbow surgery or fracture/dislocation and those undergoing revision or additional simultaneous procedures were excluded. Using their institution's information technology value tools, the authors extracted prospectively collected surgical encounter total direct costs data for each surgical encounter. Costs were compared between groups and modeled using univariate and multivariable gamma regression.

RESULTS

In situ decompression, subcutaneous transposition, and submuscular transposition were performed on 45, 62, and 14 unique surgical encounters, respectively, with mean surgical times of 28.0, 46.5, and 50.0 minutes, respectively. Costs differed significantly between surgical methods. Surgical method and provider significantly affected surgical encounter total direct costs in the univariate model. Multivariable modeling demonstrated that subcutaneous transposition was 1.18-fold more costly than in situ decompression and submuscular transposition was 1.55-fold more costly than in situ decompression while controlling for age, sex, and provider.

CONCLUSIONS

Surgical costs differed significantly between in situ decompression, subcutaneous transposition, and submuscular transposition. Given historically similar outcomes reported for these techniques, cost differences should be considered in addition to clinical factors to inform surgical decision-making for cubital tunnel syndrome patients.

A Novel Diagnostic and Prognostic Tool for Simple Decompression of Ulnar Nerve in Cubital Tunnel Syndrome

BACKGROUND

Surgical decompression of the ulnar nerve (UN) is effective for treating cubital tunnel syndrome (CubTS). Nevertheless, the outcome is not always satisfying. Different surgical, clinical, and imaging findings have been claimed as outcome predictors, but there is no consensus in the literature. We analyzed the outcome-predicting role of ultrasonography (US) of the UN in patients with CubTS and its possible role for diagnosis and follow-up.

METHODS

Patients with CubTS treated by simple UN decompression underwent US and electrodiagnotic (ED) studies of the UN at the elbow before and after surgery. Outcome was evaluated through the Bishop scale. A correlation analysis between pre- and postoperative clinical, US, and ED findings was performed.

RESULTS

Thirty-six patients were enrolled. Preoperatively, we observed a negative correlation between the motor conduction velocity (MCV) and the transverse (TD) and anteroposterior diameters and cross-sectional area (CSA) of the UN at the precubital (P = 0.001, P = 0.001, P = 0.005) and cubital level (P = 0.02, P = 0.002, P = 0.001). Preoperative precubital TD and CSA were associated with outcome (P = 0.01, P = 0.006) and postoperative MCV (P = 0.004, P = 0.008). The cut-off values TD >6 mm and CSA >23.91 mm² were predictors of poor outcome. Finally, postoperative cubital TD and CSA values were inversely correlated with outcome (P = 0.0002, P = 0.0007) and postoperative MCV (P = 0.0002, P = 0.0004).

CONCLUSIONS

The US examination of the UN is useful for the management of patients with CubTS as an adjunct to clinical and ED evaluations. US measurements are correlated with pre- and postoperative ED findings and thus are useful for diagnosis and follow-up. Interestingly, specific precubital US measurements are good predictors of outcome.

Comparative Morbidity of Cubital Tunnel Surgeries: A Prospective Cohort Study

PURPOSE

Randomized controlled trials have not identified a superior surgical approach to cubital tunnel syndrome surgery. This study evaluates the early morbidity of open in situ decompression and transposition.

METHODS

This prospective cohort study enrolled 125 adult patients indicated for cubital tunnel surgery at a tertiary institution. Exclusion criteria included preoperative use of narcotics and concurrent elbow procedures. In situ decompressions (n = 47) and ulnar nerve transpositions (n = 78) were performed. Data were collected by independent clinicians at 3 postoperative intervals: 1 to 3 weeks, 4 to 8 weeks, and longer than 8 weeks. Postoperative data quantified surgical morbidity: visual analog scale (0-10) surgical site pain, narcotic consumption, patient-reported disability (Levine-Katz, Patient-Reported Elbow Evaluation [PREE] scores). Olecranon paresthesia and wound complications (hematoma, drainage, infection) were recorded.

RESULTS

No preoperative differences in age, sex, or the presence of pain existed between the surgical groups. Surgical site pain was not significantly different at any time. Following transposition, a significantly greater percentage of patients were using narcotics at 4 to 8 weeks after surgery and the average total morphine equivalents consumed per patient was significantly greater. Both Levine-Katz and PREE scores indicated greater disability at 1 to 3 and 4 to 8 weeks after transposition, but this significant difference resolved by final follow-up. Olecranon paresthesias occurred after both procedures but were significantly less frequent at 4 to 8 weeks and longer than 8 weeks after decompression. Twelve hematomas occurred following transposition (15%) with 1 requiring operative debridement and 5 hematomas resolved with nonsurgical treatment after in situ decompression (11%).

CONCLUSIONS

Ulnar nerve transposition imparts greater surgical morbidity than decompression with greater narcotic consumption, more patient-reported disability up to 8 weeks after surgery, and more persistent olecranon paresthesia. However, most differences in surgical morbidity are transient with resolution after 8 weeks following surgery.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

Predictors of postoperative outcomes of cubital tunnel syndrome treatments using multiple logistic regression analysis

BACKGROUND

This retrospective study was designed to investigate prognostic factors for postoperative outcomes for cubital tunnel syndrome (CubTS) using multiple logistic regression analysis with a large number of patients.

METHODS

Eighty-three patients with CubTS who underwent surgeries were enrolled. The following potential prognostic factors for disease severity were selected according to previous reports: sex, age, type of surgery, disease duration, body mass index, cervical lesion, presence of diabetes mellitus, Workers' Compensation status, preoperative severity, and preoperative electrodiagnostic testing. Postoperative severity of disease was assessed 2 years after surgery by Messina's criteria which is an outcome measure specifically for CubTS. Bivariate analysis was performed to select candidate prognostic factors for multiple linear regression analyses. Multiple logistic regression analysis was conducted to identify the association between postoperative severity and selected prognostic factors.

RESULTS

Both bivariate and multiple linear regression analysis revealed only preoperative severity as an independent risk factor for poor prognosis, while other factors did not show any significant association.

CONCLUSIONS

Although conflicting results exist regarding prognosis of CubTS, this study supports evidence from previous studies and concludes early surgical intervention portends the most favorable prognosis.

Postoperative improvement in DASH score, clinical findings, and nerve conduction velocity in patients with cubital tunnel syndrome

We investigated a recovery pattern in subjective and objective measures among 52 patients with cubital tunnel syndrome after anterior subcutaneous transposition of the ulnar nerve. Disabilities of the Arm, Shoulder and Hand (DASH) score (primary outcome), numbness score, grip and pinch strength, Semmes-Weinstein (SW) score, static 2-point discrimination (2PD) score, and motor conduction velocity (MCV) stage were examined preoperatively and 1, 3, 6, 12, and ≥24 months postoperatively. Statistical analyses were conducted to evaluate how each variable improved after surgery. A linear mixed-effects model was used for continuous variables (DASH score, numbness, grip and pinch strength), and a proportional odds model was used for categorical variables (SW and 2PD tests and MCV stages). DASH score significantly improved by 6 months. Significant recovery in numbness and SW test scores occurred at 1 month. Grip and pinch strength, 2PD test scores, and MCV stage improved by 3 months. DASH scores and numbness recovered regardless of age, sex, or disease severity. It was still unclear if both subjective and objective measures improved beyond 1-year postoperatively. These data are helpful for predicting postoperative recovery patterns and tend to be most important for patients prior to surgery.

The relationship between the Patient-rated Ulnar Nerve Evaluation and the common impairment measures of grip strength, pinch strength, and sensation

STUDY DESIGN

Prospective cohort study.

INTRODUCTION

Grip strength, pinch strength, and sensory threshold are common evaluations used on a daily basis. Identifying how these variables relate to function for patients allows these assessments to be used for screening to identify who may benefit from surgical intervention, and provides valuable information about what impairments patients think are important with respect to functional use of their upper extremity. Therapists can use this information to focus rehabilitation programs on the most important impairments.

PURPOSE

To evaluate the relationship between the Patient-rated Ulnar Nerve Evaluation (PRUNE) and impairment measures of grip strength, pinch strength, and one-point sensory threshold.

METHODS

Data was prospectively collected from 77 patients before surgery and during regular time points for 2 years following surgery. Patients completed the PRUNE, grip and pinch strength measures, and a one-point sensory threshold evaluation. Correlations between these variables were calculated at baseline, 2 years after surgery, and for change scores during the 2-year follow up. A multiple regression analysis was used to determine the contribution of the impairment variables for determining functional change.

RESULTS

Grip strength showed moderate, statistically significant correlation with PRUNE scores at both baseline (r = -0.38) and at two years (r = -0.29). There was also a statistically significant correlation between one point sensory threshold for the small finger at two years (r = 0.36), but not at baseline. Change in grip strength (r = -0.28) and pinch strength (r = -0.30) both demonstrated significant correlations with PRUNE change scores. Overall, changes in grip strength, pinch strength, and sensation accounted for 20% of the variance in PRUNE changes.

CONCLUSION

Since grip strength was most highly correlated with PRUNE scores at baseline and at two years, rehabilitation programs that target grip strengthening is supported. While neither grip nor pinch strength were significant contributors to the regression when used together, each showed significant contributions to PRUNE variability when used in the model independently. Therefore, a combination of grip and pinch strengthening may be important during rehabilitation for improving functional results in patients that undergo surgical intervention for cubital tunnel syndrome.

LEVEL OF EVIDENCE

2b.

The Supercharge End-to-Side Anterior Interosseous-to-Ulnar Motor Nerve Transfer for Restoring Intrinsic Function: Clinical Experience

BACKGROUND

The authors reviewed their initial clinical experience with the supercharge end-to-side anterior interosseous-to-ulnar motor nerve transfer and refined their indications for this technique.

METHODS

A retrospective cohort study was performed of all patients undergoing the supercharge end-to-side procedure from 2009 to 2012. Preoperative and intraoperative data were reviewed. Function was evaluated using manual muscle testing; pinch/grip strength; and Disabilities of the Arm, Shoulder and Hand questionnaire scores. Differences in preoperative and postoperative function were evaluated using paired t tests and Wilcoxon signed rank tests. Predictors of poor outcome and changes in outcome over time were also analyzed.

RESULTS

Fifty-five patients (69 percent men; mean age, 50.0 ± 15.5 years) were included. Diagnoses were varied, but all patients demonstrated clinically significant ulnar intrinsic weakness and electrodiagnostic evidence of denervation of the first dorsal interosseous muscle. Postoperative first dorsal interosseous strength; key pinch strength; grip strength; and Disabilities of the Arm, Shoulder and Hand questionnaire scores improved significantly from baseline at a mean follow-up of 8.0 ± 5.7 months. No patients demonstrated weakness of pronation postoperatively. Absent preoperative compound muscle action potentials in the ulnar nerve significantly predicted poor intrinsic muscle recovery. The degree of intrinsic recovery attributable to the supercharge end-to-side transfer was difficult to determine.

CONCLUSIONS

The supercharge end-to-side anterior interosseous-to-ulnar nerve transfer may be a useful technique for augmenting intrinsic muscle function for severe, in-continuity lesions of the ulnar nerve where limited surgical options exist. Future research is required to determine the proportion of intrinsic recovery attributable to this transfer.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Predictors of functional outcomes after simple decompression for ulnar neuropathy at the elbow: a multicenter study by the SUN study group

OBJECTIVE

To identify predictors of surgical outcome for ulnar neuropathy at the elbow (UNE).

DESIGN

Prospective cohort followed for 1 year.

SETTING

Clinics.

PARTICIPANTS

Patients diagnosed with UNE (N=55).

INTERVENTION

All subjects had simple decompression surgery.

MAIN OUTCOME MEASURES

The primary outcome measure was patient-reported outcomes, such as overall hand function through the Michigan Hand Outcomes Questionnaire (MHQ). Predictors included age, duration of symptoms, disease severity, and motor conduction velocity across the elbow.

RESULTS

Multiple regression models with change in the overall MHQ score as the dependent variable showed that at 3 months postoperative time, patients with <3 months duration of symptoms showed 12 points (95% confidence interval [CI], 0.9-23.5) greater improvement in MHQ scores than those with ≥3 months symptom duration. Less than 3 months of symptoms was again associated with 13 points (95% CI, 2.9-24) greater improvement in MHQ scores at 6 months postoperative, but it was no longer associated with better outcomes at 12 months. A worse baseline MHQ score was associated with significant improvement in MHQ scores at 3 months (coefficient, -0.38; 95% CI, -.67 to -.09), and baseline MHQ score was the only significant predictor of 12 month MHQ scores (coefficient, -.40; 95% CI, -.79 to -.01).

CONCLUSIONS

Subjects with <3 months of symptoms and worse baseline MHQ scores showed significantly greater improvement in functional outcomes as reported by the MHQ. However, duration of symptoms was only predictive at 3 or 6 months because most patients recovered within 3 to 6 months after surgery.