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

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.

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.

Evaluation of PROMIS Outcomes for Surgical Treatment of Cubital Tunnel Syndrome With and Without Carpal Tunnel Syndrome

BACKGROUND

Assessment of outcomes for cubital tunnel syndrome (CuTS) surgeries has been difficult due to heterogeneity in outcome reporting. Our objective was to evaluate the outcomes for 2 cohorts treated surgically for isolated CuTS and for combined CuTS and carpal tunnel syndrome (CTS) using Patient Reported Outcomes Measurement Information System (PROMIS).

METHODS

There were 29 patients in the isolated CuTS cohort and 30 patients in the combined CuTS and CTS cohort. PROMIS Physical Function (PF), Pain Interference (PI), Depression, and Upper Extremity (UE) were completed preoperatively and 1-week, 6-weeks, and 3-months postoperatively. Responsiveness was evaluated by standardized response means (SRM).

RESULTS

Significant improvements from the 1-week to 6-week postoperative period are shown in the isolated CuTS cohort for PROMIS PF (P = .002), PI (P = .0002), and UE (P = .02), but scores plateau after 6-weeks postoperatively. A similar pattern for the same time points was seen for the combined CuTS and CTS group for PROMIS PF (P = .001), PI (P = .02), and UE (P = .04), with a plateau of scores beyond 6 weeks postoperatively. PROMIS UE was more responsive (SRM range: 0.11-1.03) than the PF (SRM range: 0.02-0.52) and PI (SRM range: 0.11-0.40), which were both mildly responsive for both cohorts.

CONCLUSIONS

PROMIS lacks the sensitivity to show improvement beyond 6-weeks postoperatively for both isolated CuTS and combined CuTS and CTS. Patients with combined nerve compressions follow similar trajectories in the postoperative period as those with isolated CuTS.

LEVEL OF EVIDENCE

Level IV.

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.

Outcome of Simple Decompression of Primary Cubital Tunnel Syndrome Based on Patient-Reported Outcome Measurements

PURPOSE

To evaluate the patient-reported outcome measures of patients with primary cubital tunnel syndrome and to assess whether they are affected by preoperative symptom severity.

METHODS

Patients who underwent simple decompression for primary cubital tunnel syndrome were selected from a prospectively maintained database. Outcome measurements consisted of the Boston Carpal Tunnel Questionnaire at intake and at 3 and 6 months after surgery. Also, 6 months after surgery, the patients received a question about their satisfaction with the treatment result. To determine a possible influence of preoperative symptom severity on postoperative outcomes, the sample was divided into quartiles based on symptom severity at intake.

RESULTS

One hundred and forty-five patients were included in the final analysis. On average, all patients improved on the Boston Carpal Tunnel Questionnaire. The subgroup of patients with the mildest symptoms at intake did not improve significantly on symptom severity but did improve significantly on their functional status. In addition, the patients with the most severe symptoms at intake did improve on both aspects. Moreover, no difference in satisfaction with treatment result between the severity of symptoms at intake was found.

CONCLUSIONS

The patients with the mildest symptoms at intake may not improve on symptom severity, but they do improve on functional status after simple decompression for cubital tunnel syndrome. In addition, patients with the most severe symptoms at intake do improve on both symptom severity and functional status. Moreover, all patients reported to be equally satisfied with the treatment result, which suggests that satisfaction is not dependent on the symptom severity at intake. Even those patients with both the mildest symptoms before surgery and the least improvement still seem to benefit from simple decompression.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Ulnar nerve decompression and transposition with versus without supercharged end-to-side motor nerve transfer for advanced cubital tunnel syndrome: a randomized comparison study

OBJECTIVE

The objective of this prospective randomized study was to compare ulnar nerve decompression and anterior subfascial transposition with versus without supercharged end-to-side anterior interosseous nerve-to-ulnar motor nerve transfer for advanced cubital tunnel syndrome, to describe performing the nerve transfer through a small incision, and to investigate predictive factors for poor recovery following the procedure.

METHODS

Between January 2013 and October 2016, 93 patients were randomly allocated to a study group (n = 45) and a control group (n = 48). Patients in the study group were treated with supercharged motor nerve transfer via a 5-cm incision following decompression and anterior subfascial transposition. Patients in the control group were treated with decompression and anterior subfascial transposition alone. Postoperative pinch strength and compound muscle action potential amplitude (CMAPa) were assessed. Function of the limb was assessed based on the Gabel/Amadio scale. Between-group data were compared, and significance was set at p < 0.05. Potential risk factors were collected from demographic data and disease severity indicators.

RESULTS

At the final follow-up at 2 years, the results of the study group were superior to those of the control group with regard to postoperative pinch strength (75.13% ± 7.65% vs 62.11% ± 6.97%, p < 0.05); CMAPa of the first dorsal interossei (17.17 ± 5.84 mV vs 12.20 ± 4.09 mV, p < 0.01); CMAPa of abductor digiti minimi (11.57 ± 4.04 mV vs 8.43 ± 6.11 mV, p < 0.01); and excellent to good results (0.67 for the study group vs 0.35 for the control group, p < 0.05). Multivariate analysis showed that the advanced age (OR 2.98, 95% CI 2.25-4.10; p = 0.003) in the study group was related to unsatisfactory outcome in the patients.

CONCLUSIONS

In the treatment of advanced cubital tunnel syndrome, additional supercharged end-to-side anterior interosseous nerve-to-ulnar motor nerve transfer may produce a better function of the hand. The authors also found that cases in the elderly were related to unsatisfactory postoperative results for these patients and that they could be informed of the possibility of worsening surgery results.

Evidence-Based Approach to Timing of Nerve Surgery: A Review

ABSTRACT

Events causing acute stress to the health care system, such as the COVID-19 pandemic, place clinical decisions under increased scrutiny. The priority and timing of surgical procedures are critically evaluated under these conditions, yet the optimal timing of procedures is a key consideration in any clinical setting. There is currently no single article consolidating a large body of current evidence on timing of nerve surgery. MEDLINE and EMBASE databases were systematically reviewed for clinical data on nerve repair and reconstruction to define the current understanding of timing and other factors affecting outcomes. Special attention was given to sensory, mixed/motor, nerve compression syndromes, and nerve pain. The data presented in this review may assist surgeons in making sound, evidence-based clinical decisions regarding timing of nerve surgery.

Ulnar Nerve Entrapment in Diabetes: Patient-reported Outcome after Surgery in National Quality Registries

BACKGROUND

Ulnar nerve entrapment at the elbow (UNE) is overrepresented in patients with diabetes, but the outcome of surgery is unknown. We aimed to evaluate patient-reported outcome in patients with and without diabetes, and to assess potential sex differences and compare surgical treatment methods.

METHODS

Data on patients operated for UNE (2010-2016, n = 1354) from the Swedish National Registry for Hand Surgery were linked to the Swedish National Diabetes Register. Symptoms were assessed preoperatively (n = 389), and 3 (n = 283), and at 12 months postoperatively (n = 267) by QuickDASH and HQ-8 (specific hand surgery questionnaire-8 questions). Only simple decompressions were included when comparing groups.

RESULTS

Men with diabetes reported higher postoperative QuickDASH scores than men without diabetes. Women scored their disability higher than men on all time-points in QuickDASH, but showed larger improvement between preoperative and 12 months postoperative values. Patients operated with transposition scored 10.8 points higher on QuickDASH than patients who had simple decompression at 12 months (95% confidence interval 1.98-19.6).

CONCLUSIONS

Women with diabetes benefit from simple decompression for UNE to the same extent as women without diabetes. Men with diabetes risk not to benefit from simple decompression as much as women do. Ulnar nerve transposition had a higher risk of residual symptoms compared to simple decompression.

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.