The scratch collapse test: A systematic review

The Scratch-Collapse Test: Are Electrodiagnostic Changes Measurable?

INTRODUCTION

Carpal tunnel syndrome is commonly managed by hand and upper extremity surgeons. Though electrodiagnostics are considered the gold standard diagnosis, the scratch collapse test (SCT) was introduced to address uncertainty, despite remains controversial. To address this, we sought to identify if the SCT can correlate with EDS studies if the SCT can identify actual changes in measures of nerves.

METHODS

We reviewed patients who underwent electrodiagnostic studies (EDX) and SCT for carpal tunnel syndrome (CTS). Demographic data as well as sensorimotor amplitudes, latencies, and velocities on nerve conduction and electromyography were collected. Analogous values based on SCT findings were analyzed for statistical significance.

RESULTS

Three hundred fifty patients with CTS were included. Sensory and motor velocities and amplitudes were significantly lower in patients with a positive SCT. Motor values were independent of age, though younger patients had larger measured changes. Obese patients did not show any motor EDX changes with the scratch collapse test, though thinner patients did. All changes were seen in nerve conduction only.

CONCLUSIONS

Carpal tunnel can be a difficult problem to diagnose as one study does not singularly determine the condition. The SCT was introduced to facilitate easier diagnosis. We demonstrate that the SCT correlates with changes on nerve conduction studies, especially in relation to decreased amplitudes and velocities, suggesting that it does identify changes in nerve with compression, specifically axonal, and myelin damage. These findings support the use of the SCT maneuver to evaluate and diagnose in appropriate patients.

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.

A case report: Pain in the hand and tingling of the upper limb may be a symptom of a schwannoma in the supraclavicular region

INTRODUCTION

Schwannomas, or neurilemmomas, are rare benign nerve sheath tumors primarily originating from peripheral nerves. Brachial plexus schwannomas, constituting approximately 5 % of cases, present a diagnostic and surgical challenge due to their rarity and the complex anatomy of the brachial plexus.

CASE PRESENTATION

We present the case of a 51-year-old man who visited our physiotherapy clinic with a two-year history of intermittent pain and tingling in the fourth and fifth metacarpals of his non-dominant hand (Numeric Pain Rating Scale 2/10). The pain was nocturnal and resistant to various treatments. Physical examination did not reveal "red flag" symptoms. Considering the persistent and atypical nature of the symptoms, further diagnostic investigations, including an ultrasound of the supraclavicular region, were recommended.

CLINICAL DISCUSSION

Our case report emphasizes the importance of considering brachial plexus schwannomas in patients with prolonged and unconventional symptoms in the fourth and fifth digits, accompanied by supraclavicular swelling and a positive Tinel's sign. Comprehensive diagnostic evaluation is crucial to confirm or rule out a schwannoma in the supraclavicular area. The rarity of such tumors and the intricate brachial plexus anatomy require meticulous diagnostic and surgical approaches.

CONCLUSIONS

This case adds to the growing understanding of brachial plexus schwannomas and their diagnostic complexities. Our report underscores the significance of recognizing these tumors in patients with distinct symptomatology and highlights the need for detailed diagnostic assessments and surgical planning.

Sensitivity and Specificity of Examination Maneuvers for Carpal Tunnel Syndrome: A Meta-Analysis

Our purpose was to assess the diagnostic validity (sensitivity (Sn) and specificity (Sp)) of physical examination maneuvers for carpal tunnel syndrome (CTS). This meta-analysis utilized the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. Studies assessing exam maneuvers (including components of the CTS-6) for CTS were identified in MEDLINE (Medical Literature Analysis and Retrieval System Online) and Embase (Excerpta Medica Database) databases. Assessed maneuvers assessed included: Phalen's test, Tinel's sign, Durkan test, scratch-collapse test, Semmes-Weinstein monofilament (SWM), and static 2-point discrimination (2PD) test. Data extracted included: article name, total number of subjects/hands, type of exam, and exam Sn/Sp. Forest plots were presented to display the estimated Sn/Sp and boxplots were used to demonstrate the locality, spread, and skewness of the Sn/Sp through the quartiles. After screening 570 articles, 67 articles involving 8924 hands were included. Forty-eight articles assessed Phalen's test, 45 assessed Tinel's sign, 21 assessed the Durkan test, seven assessed the scratch-collapse test, 11 assessed SWM, and six assessed the static 2PD test. Phalen's test demonstrated the greatest median Sn (0.70, (Q1, Q3): (0.51, 0.85)), followed by the Durkan test (0.67, (Q1, Q3): (0.46, 0.82)). 2PD demonstrated the highest median Sp (0.90, (Q1, Q3): (0.88, 0.90)), followed by SWM (0.85, (Q1, Q3): (0.51, 0.89)). There is considerable variability with respect to the validity of physical exam tests used in the diagnosis of CTS. Upper-extremity surgeons should be aware of inherent limitations for individual exam maneuvers. In the absence of a uniformly accepted diagnostic gold standard, a combination of exams, along with pertinent patient history, should guide the diagnosis of CTS.

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.

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.

“Idiopathic” Shoulder Pain and Dysfunction from Carpal Tunnel Syndrome and Cubital Tunnel Syndrome

As a referral center for chronic pain, we see many patients with “idiopathic” shoulder pain and limited range of motion. The combination of mild or subclinical carpal tunnel syndrome and cubital tunnel syndrome may be an underrecognized etiology of symptoms in such patients. Here, we report our treatment algorithm and results for such patients.