The "hierarchical" Scratch Collapse Test for identifying multilevel ulnar nerve compression

Optimizing Outcomes in Revision Peripheral Nerve Surgery of the Upper Extremity

Peripheral nerve surgeries for compressive neuropathy in the upper extremity are generally successful. However, cases that either fail or have complications requiring revision surgery are challenging. During revision consideration, surgeons should perform a comprehensive preoperative workup to understand the etiology of the patient's symptoms and categorize symptoms as persistent, recurrent, or new in relation to the index procedure. Revision surgery often requires an open, extensile approach with additional procedures to optimize outcomes. Even with proper workup and treatment, clinical outcomes of revision surgeries are inferior compared to primary surgeries and patients should be well informed prior to undergoing such procedures.

The role of the exhaustion test in lacertus syndrome

BACKGROUND

Lacertus syndrome involves dynamic median nerve compression by the lacertus fibrosus, leading to sensory symptoms and loss of strength. Prevalence in the general population is unclear.

OBJECTIVE

This study aimed to determine the prevalence of lacertus syndrome in the Belgian population and to evaluate the effectiveness of the exhaustion test combined with the scratch collapse test.

METHODS

In a cross-sectional study from May 2023 to February 2024, 362 healthy individuals, aged 18 to 86 years underwent clinical examinations, including the scratch-collapse test and exhaustion test, to assess signs of lacertus syndrome.

RESULTS

11.3% of participants (95% CI: 8.2-15.1%) reported discomfort on lacertus fibrosus palpation. The scratch-collapse test at the lacertus fibrosus was positive in 7.2% of cases (95% CI: 4.8-10.4%), increasing to 25.7% (95% CI: 21.3-30.5%, p < 0.001) following the exhaustion test. There were no significant differences in gender, occupation, or hand dominance (all p > 0.05). Hagert's clinical triad and positive scratch-collapse test over the lacertus fibrosus were found in 2.21% (95% CI: 1.0-4.2%) of this general population after the exhaustion test.

CONCLUSION

The prevalence of lacertus syndrome was 2.21% after the exhaustion test, and 0.83% before. The exhaustion test led to significant conversion of negative to positive scratch-collapse test from 7.2% to 25.7%. The exhaustion test enhanced the scratch-collapse test's diagnostic accuracy, revealing a spectrum of lacertus syndrome symptoms, from unnoticed mild cases to severe manifestations, and confirmed the importance of Hagert's clinical triad in diagnosing lacertus syndrome.

Updates to the Physiologic Mechanism, Anatomical Sites, and Diagnostic Utility of the Scratch Collapse Test: A Systematic Review

Background

The scratch collapse test (SCT) has gained popularity as a physical examination technique for diagnosing compression neuropathy. This systematic review aims to assess the reliability of the SCT as a diagnostic tool for compression neuropathy, as well as to propose the underlying physiological mechanisms involved. Specific criteria was developed to broaden the potential anatomical applications of the SCT.

Methods

A literature search was conducted using PubMed, Embase, Scopus, and Google Scholar. Eleven articles meeting predefined inclusion/exclusion criteria were selected for numerical analysis, which yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy values.

Results

In total, 890 patients with carpal tunnel syndrome were reported in 10 studies. The mean (±SD) sensitivity, specificity, PPV, NPV, and accuracy were 0.442 ± 0.272, 0.788 ± 0.163, 0.834 ± 0.143, 0.433 ± 0.297, and 48.8% (range, 31%-82%), respectively. Of the studies that provided interrater reliability (κ), the mean was 0.544 ± 0.441, indicating moderate agreement. A total of 121 patients with cubital tunnel syndrome were reported in three studies, with a mean (±SD) sensitivity and specificity of 0.635 ± 0.367 and 0.945 ± 0.06, respectively. Twenty-four patients with peroneal nerve compression, reported in one study, had sensitivity, specificity, PPV, NPV, and accuracy of 0.77, 0.99, 0.95, 0.92, and 93%, respectively.

Conclusions

Current literature indicates that the SCT can serve as a provocative test to assist in diagnosing compression neuropathy. Nevertheless, the heterogeneity of reported values underscores the necessity for further investigation aimed at enhancing the objectivity of SCT, thus improving interrater reliability and minimizing potential bias.

Posterior Interosseous Nerve Compression in the Forearm, AKA Radial Tunnel Syndrome: A Clinical Diagnosis

BACKGROUND

Posterior interosseous nerve (PIN) compression in the forearm without motor paralysis is a challenging clinical diagnosis. This retrospective study evaluated the clinical assessment, diagnostic studies, and outcomes following surgical decompression of the PIN in the forearm.

METHODS

This study reviewed 182 patients' medical charts following PIN decompression between 2000 and 2020 by a single surgeon. After exclusion of combined nerve entrapments, polyneuropathy, motor palsy, or lateral epicondylitis, the study included 14 patients. Data collected included: clinical presentation and pain drawings, provocative testing, functional outcomes, and Disabilities of the Arm, Shoulder, and Hand (DASH) scores.

RESULTS

There were 15 PIN decompressions (14 patients, mean follow-up = 11.9 months). Clinical presentation included pain (n = 14) (proximal dorsal forearm, n = 14; distal forearm over radial sensory nerve, n = 3) and positive clinical tests (sensory collapse test over the radial tunnel, n = 8; pain with forearm pronation and compression over the radial tunnel, n = 10; Tinel sign, n = 5). Postoperatively, there were significant improvements in Visual Analog Scale pain scores (6.7 to 3.3, P = .0006), quality-of-life scores (74.7 to 32.7, P = .0001), and DASH scores (46.3 to 33.6, P = .02).

CONCLUSIONS

The PIN compression in the forearm without motor paralysis is a clinical diagnosis supported by pain drawings, pain quality, and provocative tests. Patients with persistent, therapy-resistant dorsal forearm pain should be evaluated for PIN compression. Surgical decompression provides statistically significant quantifiable improvement in pain and quality of life.

Compression of the Ulnar Nerve by the Arcade of Struthers: Look and You Shall Find

BACKGROUND

The arcade of Struthers was first proposed by Kane et al in 1973. Clinical investigations of this structure have been limited to small case series, focusing on the arcade as an isolated cause of compressive ulnar neuropathy. The purpose of our study was to investigate the incidence of this structure in patients undergoing ulnar nerve transposition.

METHODS

A retrospective chart review of prospectively maintained data in a single surgeon's practice was performed. Records of patients undergoing surgery for compressive ulnar neuropathy at the cubital tunnel were evaluated for documentation of a compressive arcade of Struthers. In addition, a scoping review of the literature was undertaken to better characterize current understanding of this structure and its recognition in clinical practice.

RESULTS

A total of 197 patients underwent ulnar nerve transposition. The overall incidence of a compressive arcade of Struthers was noted to be 67 out of 197 (34%). All patients with a compressive arcade were noted to have an internal brachial ligament running below the nerve. Patients undergoing revision surgery were found to have a compressive arcade 51% of the time (20/39), whereas 30% of patients undergoing primary surgery were found to have a compressive arcade (47/158). Only 12 clinical studies examining the arcade of Struthers have been published in the last 20 years, the majority being single case reports.

CONCLUSIONS

Compression of the ulnar nerve by the arcade of Struthers is a common finding and can contribute to compressive ulnar neuropathy at the elbow both in primary and revision cases.

A positive scratch collapse test in anterior cutaneous nerve entrapment syndrome indicates its neuropathic character

OBJECTIVES

Chronic abdominal pain is occasionally caused by an abdominal wall entity such as anterior cutaneous nerve entrapment syndrome (ACNES). This syndrome is thought to occur due to intercostal nerve branches (T7-12) that are entrapped in the rectus abdominis muscles. The diagnosis is largely based on subjective clues in patient history and physical examination. A test referred to as the scratch collapse test (SCT) is used as an additional diagnostic tool in peripheral nerve entrapment syndromes such as the carpal tunnel syndrome. The aim of the present study is to investigate whether an SCT was positive in patients with suspected ACNES. If so, this finding may support its hypothesized neuropathic character.

METHODS

A prospective, case-control study was performed among patients with ACNES (n = 20) and two control groups without ACNES (acute intra-abdominal pathology n = 20; healthy n = 20), all were consecutively included. ACNES was diagnosed based on previously published criteria. The SCT test was executed at the painful abdominal area in both patient groups and at a corresponding area in healthy controls. Predictive values, sensitivity, and specificity were calculated. Videos of tests were evaluated by blinded observers.

RESULTS

SCT was judged positive in 19 of 20 ACNES patients but not in any of the 40 controls. A 95% sensitivity (confidence interval [CI]: 75-99) and optimal specificity (100%; CI: 83-100) were calculated.

CONCLUSIONS

The positive SCT supports the hypothesis that ACNES is an entrapment neuropathy. A positive SCT should be considered a major diagnostic criterion for ACNES.

The prevalence of double- and multiple crush syndromes in patients surgically treated for peripheral nerve compression in the upper limb

OBJECTIVE

The double crush syndrome describes a condition characterized by multifocal entrapment of a nerve. In the upper limb, the high prevalence of carpal tunnel syndrome makes it a common diagnosis of assumption in the setting of median neuropathy. More proximal compressions may tend to be overlooked, under-diagnosed and under-treated in the population. This study aims to map the prevalence of peripheral upper limb nerve compressions among patients undergoing peripheral nerve decompression.

METHODS

A prospective case series was conducted on 183 patients undergoing peripheral nerve decompression in a private hand surgery clinic. Level(s) of nerve compression in the median, ulnar and radial nerves were determined by history and physical examination. The prevalence of each nerve compression syndrome or combination of syndromes was analyzed.

RESULTS

A total of 320 upper limbs in 183 patients were analyzed. A double crush of the median nerve at the levels of the lacertus fibrosus and carpal tunnel was identified in 78% of upper limbs with median neuropathy, whereas isolated lacertus syndrome and carpal tunnel syndrome were present in only 5% and 17% of affected limbs respectively. Cubital tunnel syndrome affected 12.5% of upper limbs, and 80% of these had concomitant lacertus and carpal tunnel syndromes, compared to only 7.5% with isolated cubital tunnel syndrome.

CONCLUSION

A high prevalence should prompt clinicians towards more routine assessment for double crush syndrome to avoid misdiagnosis, inadequate treatment, recurrence, and revision surgeries.

The Scratch Collapse Test in patients diagnosed with Anterior Cutaneous Nerve Entrapment Syndrome (ACNES): A report of three cases

INTRODUCTION AND IMPORTANCE

The Scratch Collapse Test (SCT) is currently used as a supportive tool diagnosing peripheral nerve neuropathies including carpal tunnel syndrome or peroneal nerve entrapment. Some patients with chronic abdominal pain suffer from entrapment of terminal branches of intercostal nerves (anterior cutaneous nerve entrapment syndrome, ACNES). ACNES is characterized by a severe disabling pain at a predictable area of the anterior abdomen. Clinical examination shows altered skin sensation and painful pinching at the area of pain. However, these findings may be subjective.

CASE PRESENTATION

In three female patients aged 71, 33, and 43 years with suspected ACNES, the SCT was positive when scratching over the skin of the affected nerve-ending at the abdominal wall. The diagnosis ACNES was confirmed with a local abdominal wall infiltration at the tenderpoint in all three patients. In case three, the SCT turned negative after lidocaine infiltration.

CLINICAL DISCUSSION

ACNES was hitherto a clinical diagnosis just based on clues in medical history and physical examination. Performing a SCT in patients possibly having ACNES may additionally contribute to the diagnosis.

CONCLUSION

The SCT may serve as an additional tool for diagnosing patients with possible ACNES. A positive SCT in patients with ACNES supports the hypothesis that ACNES is indeed a peripheral neuropathy of terminal branches of the lower thoracic intercostal nerves. Controlled research is necessary to confirm the role of a SCT in ACNES.

Current Concepts in the Management of Neurogenic Thoracic Outlet Syndrome: A Review

Thoracic outlet syndrome is a constellation of signs and symptoms due to compression of the neurovascular bundle of the upper limb. In particular, neurogenic thoracic outlet syndrome can present with a wide constellation of clinical manifestations ranging from pain to paresthesia of the upper extremity, resulting in a challenge to correctly diagnose this syndrome. Treatment options range from nonoperative treatment, such as rehabilitation and physical therapy, to surgical correction, such as decompression of the neurovascular bundle.

Methods

Following a systematic review of the literature, we describe the need for a thorough patient history, physical examination, and radiologic images which have been reported to correctly diagnose neurogenic thoracic outlet syndrome. Additionally, we review the various surgical techniques recommended to treat this syndrome.

Results

Postoperative functional outcomes have been shown to be more favorable in arterial and venous thoracic outlet syndrome (TOS) patients when compared with neurogenic TOS patients, likely due to the ability to completely remove the site of compression in cases of vascular TOS as compared with incomplete decompression in neurogenic TOS.

Conclusions

In this review article, we provide an overview of the anatomy, etiology, diagnostic modalities, and current treatment options of correcting neurogenic TOS. Additionally, we offer a detailed step-by-step technique of the supraclavicular approach to the brachial plexus, a preferred approach for decompressing neurogenic TOS.

Validity of Using the Scratch Collapse Test in the Lower Extremities

BACKGROUND

The scratch collapse test is a provocative test that has been successfully used for peripheral neuropathies. The elbow is the main testing site, but there may be times when use of the upper extremities is contraindicated. This study sought to determine the sensitivity of using the scratch collapse test on the lower extremity for upper extremity neuropathies.

METHODS

One hundred patients with an electromyographically confirmed diagnosis of carpal tunnel or cubital tunnel syndrome were prospectively enrolled. As a control, the scratch collapse test was conducted normally using the elbow as a testing site. After a baseline was established, the test was repeated using eversion of the foot and ankle against an inversion force.

RESULTS

Of the 100 study patients, 89 had a positive scratch collapse test on the upper extremity and 84 had a positive test on the lower extremity. In the 51 patients with carpal tunnel syndrome, 45 had a positive test on the upper extremity (sensitivity, 88.2 percent; 95 percent CI, 76.13 to 95.56 percent), and 42 had a positive test of the lower extremity (sensitivity, 82.35 percent; 95 percent CI, 69.13 to 91.60 percent). In the 49 patients with cubital tunnel syndrome, 44 had a positive test on the upper extremity (sensitivity, 89.8 percent; 95 percent CI, 77.77 to 96.6 percent), and 42 had a positive test on the lower extremity (sensitivity, 85.7 percent; 95 percent CI, 72.76 to 94.06 percent).

CONCLUSION

There were no statistically significant differences in the sensitivities of the scratch collapse test on the upper or lower extremities, suggesting that the lower extremity could serve as an alternative site for the scratch collapse test.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, II.

Accuracy of the Scratch Collapse Test for Carpal Tunnel Syndrome in Comparison With Electrodiagnostic Studies

Background: The scratch collapse test (SCT) is a clinical examination maneuver that has been previously reported as a reliable and reproducible test to diagnose carpal tunnel syndrome (CTS). The initial study by Cheng et al in 2008 showed a simple test with high sensitivity. However, subsequent attempts to reproduce those findings have resulted in lower accuracy. Our goal was to evaluate the use of the SCT for patients presenting with symptoms of pain, numbness, or weakness in an upper extremity. Methods: Forty patients were referred to the electrodiagnostic (EDX) lab for evaluation of an upper extremity. One blinded examiner who was familiar with the maneuver performed the SCT on all 40 patients. Another physician or technician performed the nerve conduction study and electromyography. Patient history and accompanying physical examination findings were not revealed to the SCT examiner. Results: The relationship between the SCT performed by a blinded examiner and the EDX performed by blinded examiners was nonsignificant (P = .676) and showed a sensitivity of 0.48, specificity of 0.59, positive predictive value of 0.61, and negative predictive value of 0.45. Conclusion: Based on this study and previous findings by other authors, we would advise against the use of the SCT in CTS for important patient-care decisions, such as surgical decision-making, until future research is done. It is possible that the SCT, in combination with other physical examination maneuvers, could increase diagnostic accuracy and enhance patient management.

Revision of Carpal Tunnel Surgery

Carpal tunnel release is one of the most commonly performed upper extremity procedures. The majority of patients experience significant improvement or resolution of their symptoms. However, a small but important subset of patients will experience the failure of their initial surgery. These patients can be grouped into persistent, recurrent, and new symptom categories. The approach to these patients starts with a thorough clinical examination and is supplemented with electrodiagnostic studies. The step-wise surgical management of revision carpal tunnel surgery consists of the proximal exploration of the median nerve, Guyon’s release with neurolysis, the rerelease of the transverse retinaculum, evaluation of the nerve injury, treatment of secondary sites of compression, and potential ancillary procedures. The approach and management of failed carpal tunnel release are reviewed in this article.

Median Nerve Compression in the Forearm: A Clinical Diagnosis

Background: Median nerve entrapment in the forearm (MNEF) without motor paralysis is a challenging diagnosis. This retrospective study evaluated the clinical presentation, diagnostic studies, and outcomes following surgical decompression of MNEF. Methods: The study reviewed 147 patient medical charts following MNEF surgical decompression. With exclusion of patients with combined nerve entrapments (radial and ulnar), polyneuropathy, neurotmetic nerve injury, or median nerve motor palsy, the study sample included 27 patients. Data collected include: clinical presentation and pain, strength, provocative testing, functional outcomes, and Disabilities of the Arm, Shoulder and Hand (DASH) scores. Results: The study included 27 patients (mean follow-up = 7 months), and 13 patients had previous carpal tunnel release (CTR). Clinical presentation included pain (n = 27) (forearm, n = 22; median nerve innervated digits, n = 21; and palm, n = 21) and positive clinical tests (forearm scratch collapse test, n = 27; pain with compression over the flexor digitorum superficialis arch/pronator, n = 24; Tinel sign, n = 11). Positive electrodiagnostic studies were found for MNEF (n = 2) and carpal tunnel syndrome (n = 11). Primary CTR was performed in 10 patients and revision CTR in 7 patients. Postoperatively, there were significant (P < .05) improvements in strength, pain, quality of life, and DASH scores. Conclusions: The MNEF without motor paralysis is a clinical diagnosis supported by pain drawings, pain quality, and provocative tests. Patients with persistent forearm pain and median nerve symptoms (especially after CTR) should be evaluated for MNEF. Surgical decompression provides satisfactory outcomes.

Ultrasonographic prevalence of ulnar nerve displacement at the elbow in young baseball players

BACKGROUND

Overhead-throwing athletes are at risk of elbow injury because of valgus stress, leading to unstable ulnar nerves and neuropathy. Studies regarding ulnar nerve damage/displacement have been performed primarily in adults.

OBJECTIVE

To determine the prevalence and related factors associated with ulnar nerve displacement at the elbow in young baseball players.

DESIGN

Cross-sectional study.

PARTICIPANTS

Youth baseball players ages 10-12 years were eligible to participate. Exclusion criteria were history of neuropathic pain, trauma, or prior surgery of the upper limb. Fifty-seven participants were eligible for inclusion in the study.

MAIN OUTCOME MEASUREMENTS

Demographic data and ultrasonography findings of ulnar nerve dynamics at the cubital tunnel were analyzed in a total of 114 elbows. Elbows were grouped into nondislocation and displacement (subluxation or dislocation) groups according to ultrasound findings. Logistic generalized estimating equations were used to identify factors associated with ulnar nerve displacement.

RESULTS

Thirty-six (31.6%) elbows demonstrated sonographic findings of ulnar nerve displacement, with 13 (11.4%) subluxations and 23 (20.2%) dislocations. Fourteen (24.6%) participants experienced nerve displacement in the dominant elbow only, whereas nerve displacement in both elbows occurred in 11 (19.3%) participants. Nerve displacement in the nondominant elbow only was not observed. Hand dominance and tenderness of the arcade of Struthers' were factors associated with ulnar nerve displacement (odds ratio, 2.81, and 9.73; 95% confidence interval, 1.34-5.91 and 2.45-38.68; p = .006 and .001, respectively).

CONCLUSION

One-third of the young baseball players evaluated had ultrasonographic findings compatible with ulnar nerve displacement at the elbow. Hand dominance and tenderness of Struthers arcade were the only factors associated with ulnar nerve displacement. Ultrasound may help identify patients with ulnar nerve displacement and contribute to the understanding of its pathophysiology in young baseball players.

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.

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.

Identifying Common Peroneal Neuropathy before Foot Drop

BACKGROUND

Common peroneal neuropathy shares the same pathophysiology as carpal tunnel syndrome. However, management is often delayed because of the traditional misconception of recognizing foot drop as the defining symptom for diagnosis. The authors believe recognizing common peroneal neuropathy before foot drop can relieve pain and help improve quality of life.

METHODS

One hundred eighty-five patients who underwent surgical common peroneal neuropathy decompression between 2011 and 2017 were included. The mean follow-up time was 249 ± 28 days. Patients were classified into two stages of severity based on clinical presentation: pre-foot drop and overt foot drop. Demographics, presenting symptoms, clinical signs, electrodiagnostic studies and response to surgery were compared between these two groups. Multivariate regression analysis was used to identify variables that predicted outcome following surgery.

RESULTS

Overt foot drop patients presented with significantly lower preoperative motor function (percentage of patients with Medical Research Council grade ≤ 1: overt foot drop, 90 percent; pre-foot drop, 0 percent; p < 0.001). Pre-foot drop patients presented with a significantly higher preoperative pain visual analogue scale score (pre-foot drop, 6.2 ± 0.2; overt foot drop, 4.6 ± 0.3; p < 0.001) and normal electrodiagnostic studies (pre-foot drop, 31.4 percent; overt foot drop, 0.1 percent). Postoperatively, both groups of patients showed significant improvement in quality-of-life score (pre-foot drop, 2.6 ± 0.3; overt foot drop, 2.7 ± 0.3). Patients with obesity or a traumatic cause for common peroneal neuropathy were less likely to have improvements in quality of life after surgical decompression.

CONCLUSION

Increased recognition of common peroneal neuropathy can aid early management, relieve pain, and improve quality of life.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

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.

Pain and Function Following Revision Cubital Tunnel Surgery

BACKGROUND

The purpose of this study was to determine pain and functional outcomes following revision cubital tunnel surgery and to identify predictors of poor postoperative outcome.

METHODS

A retrospective cohort study was conducted of all patients undergoing revision cubital tunnel surgery over a 5-year period at a high-volume peripheral nerve center. Intraoperative findings, demographic and injury factors, and outcomes were reviewed. Average pain, worst pain, and impact of pain on self-perceived quality of life were each measured using a 10-cm visual analog scale (VAS). Function was evaluated using pinch and grip strength, as well as the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. Differences in preoperative and postoperative pain, strength, and DASH were analyzed using nonparametric tests. Predictors of postoperative average pain were evaluated using odds ratios and linear regression analyses.

RESULTS

The final cohort consisted of 50 patients (mean age: 46.3 ± 12.5 years; 29 [68%] male) undergoing 52 revision ulnar nerve transpositions (UNTs). Pain VAS scores decreased significantly following revision UNT. Strength and DASH scores demonstrated nonsignificant improvements postoperatively. Worse preoperative pain and greater than 1 prior cubital tunnel procedure were significant predictors of worse postoperative average pain VAS scores.

CONCLUSIONS

Patients can and do improve following revision cubital tunnel surgery, particularly as it relates to pain. Intraoperative findings during the revision procedure suggest that adherence to specific principles in the primary operation is key to prevention of secondary cubital tunnel syndrome.

The Role of the Peripheral Nerve Surgeon in the Treatment of Pain

Pain is a frequent cause of physician visits. Many physicians find these patients challenging because they often have complicated histories, emotional comorbidities, confusing examinations, difficult problems to fix, and the possibility of factitious complaints for attention or narcotic pain medications. As a result, many patients are lumped into the category of chronic, centralized pain and relegated to pain management. However, recent literature suggests that surgical management of carefully diagnosed generators of pain can greatly reduce patients' pain and narcotic requirements. This article reviews recent literature on surgical management of pain and four specific sources of chronic pain amenable to surgical treatment: painful neuroma, nerve compression, myofascial/musculoskeletal pain, and complex regional pain syndrome type II.

The scratch collapse test: A systematic review

The diagnosis of nerve compression relies on collecting diagnostic clues from the history, physical examination, imaging and diagnostic testing. There are several provocative tests to aid in the diagnosis of nerve compression. The 'Scratch Collapse Test' (SCT) has emerged as a new provocative test to assist in the localisation of peripheral nerve compression. This study aims to perform a systematic review of literature to assess the data on the reliability of the SCT as a diagnostic test for entrapment neuropathy. Ten articles were reviewed. Five articles had sufficient numerical data for analysis, and in these five articles, the positive predictive values and specificity were high, i.e. between 0.71 and 0.99 and 0.6 and 0.99, respectively, whereas other values were very variable, i.e. individual negative predictive values ranged from 0.15 to 0.92 and the sensitivity values ranged from 0.24 to 0.77. Another main finding was the versatility of the test in that it can be used for various nerve entrapments and to localise the exact level of compression. Literature suggests that SCT has potential to be used as a clinical diagnostic tool for entrapment neuropathy. However, wide variations in early literature suggest that SCT should not be used as a sole diagnostic tool but as an adjunct to a surgeon's diagnostic repertoire.

Surgical and Clinical Decision Making in Isolated Long Thoracic Nerve Palsy

BACKGROUND

Isolated long thoracic nerve palsy results in scapular winging and destabilization. In this study, we review the surgical management of isolated long thoracic nerve palsy and suggest a surgical technique and treatment algorithm to simplify management.

METHODS

In total, 19 patients who required surgery for an isolated long thoracic nerve palsy were reviewed retrospectively. Preoperative demographics, electromyography (EMG), and physical examinations were reviewed. Intraoperative nerve stimulation, surgical decision making, and postoperative outcomes were reviewed.

RESULTS

In total, 19 patients with an average age of 32 were included in the study. All patients had an isolated long thoracic nerve palsy caused by either an injury (58%), Parsonage-Turner syndrome (32%), or shoulder surgery (10%); 18 patients (95%) underwent preoperative EMG; 10 with evidence of denervation (56%); and 13 patients had motor unit potentials in the serratus anterior (72%). The preoperative EMG did not correlate with intraoperative nerve stimulation in 13 patients (72%) and did correlate in 5 patients (28%); 3 patients had a nerve transfer (3 thoracodorsal to long thoracic at lateral chest, 1 pec to long thoracic at supraclavicular incision). In the 3 patients who had a nerve transfer, there was return of full forward flexion of the shoulder at an average of 2.5 months.

CONCLUSIONS

A treatment algorithm based on intraoperative nerve stimulation will help guide surgeons in their clinical decision making in patients with isolated long thoracic nerve palsy. Intraoperative nerve stimulation is the gold standard in the management of isolated long thoracic nerve palsy.

Scratch Collapse Test for Carpal Tunnel Syndrome: A Systematic Review and Meta-analysis

Background:

Despite the fact that carpal tunnel syndrome (CTS) is the most common entrapment neuropathy, the diagnostic accuracy of clinical screening examinations for CTS is controversial. The scratch collapse test (SCT) is a novel test that may be of diagnostic advantage. The purpose of our study was to determine the diagnostic accuracy of the SCT for CTS.

Methods:

A literature search was performed using PubMed (1966 to April 2018); Ovid MEDLINE (1966 to April 2018); EMBASE (1988 to April 2018); and Cochrane Central Register of Controlled Trials (The Cochrane Library, to April 2018). We examined the studies for the pooled sensitivity, specificity, and likelihood ratios of the SCT. This review has been registered with PROSPERO (CRD42018077115).

Results:

The literature search generated 13 unique articles. Seven articles were included for full text screening and 3 articles met our inclusion criteria, all of which were level II evidence with low risk of bias (165 patients). Pooled sensitivities, specificities, positive likelihood ratio, and negative likelihood ratios were 0.32 [95% CI (0.24–0.41)], 0.62 [95% CI (0.45–0.78)], 0.75 [95% CI (0.33–1.67)], and 1.03 [95% CI (0.61–1.74)], respectively. The calculated area under the summary receiver operating characteristic (AUSROC) curve was 0.25, indicating a low diagnostic accuracy.

Conclusion:

The SCT has poor sensitivity; however, it is moderately specific. Based on the current literature and their variable quality of the evidence, we conclude that the SCT is not an adequate screening test for detecting CTS.

Osborne's Ligament: A Review of its History, Anatomy, and Surgical Importance

When discussing the pathophysiology of ulnar neuropathy, Geoffrey Vaughan Osborne described a fibrous band that can be responsible for the symptoms seen in this disorder. In this paper, we take a glimpse at the life of Osborne and review the anatomy and surgical significance of Osborne’s ligament. This band of tissue connects the two heads of the flexor carpi ulnaris and thus forms the roof of the cubital tunnel. To our knowledge, no prior publication has reviewed the history of this ligament, and very few authors have studied its anatomy in any detail. Therefore, the aim of the present paper is to elucidate this structure that is often implicated and surgically transected to decompress the ulnar nerve at the elbow.

Multifocal Neuropathy: Expanding the Scope of Double Crush Syndrome

Double crush syndrome (DCS), as it is classically defined, is a clinical condition composed of neurological dysfunction due to compressive pathology at multiple sites along a single peripheral nerve. The traditional definition of DCS is narrow in scope because many systemic pathologic processes, such as diabetes mellitus, drug-induced neuropathy, vascular disease and autoimmune neuronal damage, can have deleterious effects on nerve function. Multifocal neuropathy is a more appropriate term describing the multiple etiologies (including compressive lesions) that may synergistically contribute to nerve dysfunction and clinical symptoms. This paper examines the history of DCS and multifocal neuropathy, including the epidemiology and pathophysiology in addition to principles of evaluation and management.

Ulnar neuropathy: evaluation and management

Ulnar neuropathy is commonly encountered, both acutely after elbow trauma and in the setting of chronic compression neuropathy. Careful clinical evaluation and discerning evaluation of electrodiagnostic studies are helpful in determining the prognosis of recovery with nonoperative and operative management. Appreciation of the subtleties in clinical presentation and thoughtful consideration of the timing and type of surgical intervention are critical to optimizing outcomes after treatment of ulnar neuropathy. The potential need for decompression at both the cubital tunnel and Guyon's canal must be appreciated. Supplementation of decompression with supercharged end-to-side nerve transfer can expedite motor recovery of the ulnar intrinsic muscles in the appropriately selected patient. The emergence of nerve transfer techniques has also changed the management of acute ulnar nerve injuries.

Donor Distal, Recipient Proximal and Other Personal Perspectives on Nerve Transfers

This article presents a personal overview of nerve transfers and emphasizes the various factors that contribute to outcome following these surgeries. There is no "one result" for all nerve transfers. The results will vary depending on factors relating to the donor nerve and the recipient nerve, the degree of the surgical difficulty of the specific procedure, and issues relating to preoperative and postoperative rehabilitation. The general issues that influence all nerve injury and recovery, such as age of the patient, comorbidities, and time since injury, pertain to nerve transfers as well.