The Incidence of Double Crush Syndrome in Surgically Treated Patients

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

Cervical radiculopathy and peripheral entrapment neuropathies often have overlapping symptoms that are difficult to distinguish on physical examination. Small-scale studies have attempted to report the incidence of this phenomenon, often called double crush syndrome (DCS), with varying results. The present study aims to determine the incidence of concomitant cervical radiculopathy and peripheral nerve compression and to determine if the DCS hypothesis, which states that compression of a nerve at one site leaves it more susceptible to compression at another, is valid.

METHODS

The PearlDiver database was queried from 2010 to 2020. The incidence of peripheral neuropathy in cervical radiculopathy was assessed. Propensity score matching was used to determine if patients with cervical radiculopathy were more likely to have peripheral nerve compression compared to controls, and vice versa, to test the DCS hypothesis.

RESULTS

The database contains records of 90,772 632 patients. The incidence of carpal tunnel syndrome (CTS) or peripheral ulnar nerve compression (PUnC) in cervical radiculopathy was 9.98% and 3.15%, respectively. The incidence of both carpal tunnel syndrome and PUnC in cervical radiculopathy was 1.84%. Patients with cervical radiculopathy were more likely than matched controls to have both CTS (P < .001) and PUnC (P < .001). Patients with CTS (P < .001) and with PUnC (P < .001) were more likely to have cervical radiculopathy than the control cohort.

CONCLUSIONS

The incidence of DCS is reported. Patients with cervical radiculopathy are more likely than matched controls to have peripheral nerve compression, and vice versa, in support of the DCS hypothesis.

Patients With and Without Double Crush Syndrome Achieve Similar Rates of Clinical Improvement Following Carpal Tunnel Release

BACKGROUND

The purpose of this study is to compare outcomes of carpal tunnel release (CTR) in patients with and without double crush syndrome (DCS), defined as concurrent carpal tunnel syndrome (CTS) and cervical radiculopathy at C5-T1 on preoperative nerve conduction studies.

METHODS

Patients with preoperative nerve conduction studies who underwent unilateral, isolated CTR were retrospectively identified. All patients completed preoperative and 3-month postoperative Patient-Reported Outcomes Measurement Information System (PROMIS) upper extremity (UE) and pain interference (PI), and Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaires, and responded to the anchor question: "Since your treatment, how would you rate your overall function?" (much worse, worse, slightly worse, no change, slightly improved, improved, much improved). Preoperative, postoperative, and changes in scores for UE, PI, and QuickDASH were compared, as were the anchor question responses and rates of achieving the minimal clinically important difference (MCID).

RESULTS

Sixty-three patients with DCS and 115 patients with CTS only were included. At 3- to 4-month follow-up, absolute and change in UE, PI, and QuickDASH scores were not statistically different between patients with DCS and CTS. Rates of anchor question response and MCID achievement were comparable for patients with CTS only and DCS on each questionnaire. The MCID achievement ranged from 48.4% to 68.8% in the unmatched cohort and 48.4% to 60% in the matched group.

CONCLUSIONS

At 3 to 4 months, patients with DCS experience similar patient-reported symptomatic and functional improvement, and achieve MCID of outcome measures at comparable rates to patients with CTS only. For patients with nerve compression at the carpal tunnel and cervical spine, CTR is a reasonable first step prior to proceeding with cervical spine decompression.

Postoperative Functional Analysis of Double Crush Versus Single Peripheral Nerve Decompression: A Retrospective Study

BACKGROUND

Double crush (DC) syndrome patients presenting with C6-7 radiculopathy and median nerve compression in the carpal tunnel report greater nerve irritability and weakness postdecompression than isolated peripheral nerve decompression. We hypothesize that patient-reported outcome is inferior following release at both cervical spine and wrist versus a single site of decompression.

METHODS

Patients that underwent either anterior cervical decompression and fusion (ACDF) for C6-C7 radiculopathy, carpal tunnel release (CTR), or both within 5 years (DC) were identified. A total of 477 patients were analyzed (157 DC, 203 CTR, and 117 ACDF). Post-operative outcome Disabilities of the Arm, Shoulder, and Hand (QuickDASH), Neck Disability Index, and visual analog scale (VAS) scores were collected at an average of 2 years postoperatively.

RESULTS

QuickDASH scores were higher in the DC group versus CTR group (36 vs 22, P < .0002). Postoperative disability in the ACDF group was significantly higher than the DC group (50 vs 36, P < .017). There were no differences between ACDF and DC groups in arm pain intensity, but the CTR group demonstrated significantly greater arm pain intensity than the DC group (5.7 vs 3.6, 10-point scale, P < .01).

CONCLUSIONS

Patients undergoing ACDF and CTR have greater postoperative disability than those undergoing CTR alone, but less postoperative functional disability and pain than ACDF alone, indicating cervical radiculopathy may contribute a greater proportion of long-term disability postoperatively. Additionally, CTR had greater postoperative arm pain than DC patients, potentially indicating high rates of undiagnosed cervical radiculopathy or other sources of arm pain in these patients.

Characteristics of carpal tunnel syndrome in patients with cervical radiculopathy: A cross-sectional study

Background and Aims

Cervical radiculopathy (CR) is a group of signs and symptoms caused by cervical root dysfunction. Patients with this condition may also have carpal tunnel syndrome (CTS), which is caused by compression of the median nerve in the carpal tunnel. This coexistent condition is referred to as double crush syndrome (DCS) which is explained by proximal disruption in axoplasmic flow that may result in nerve dysfunction. Yet, the accuracy of this hypothesis remains controversial.

Materials and Methods

Patients with confirmed CR according to electromyography were included in this retrospective study. However, we omitted patients with overt diabetic neuropathy, prior spinal or hand surgery and/or fractures, and rheumatoid arthritis. Patients underwent electrodiagnostic studies, and the results were used to determine CTS severity. We used Pearson's χ 2 test to assess the correlation between the severity of CTS and CR. Descriptive analysis was used to report patient characteristics and the prevalence of CTS in CR patients.

Results

We included 291 participants, 59% of whom were women. Although insignificant, DCS was observed more in women (n = 110) compared to men (n = 71). However, we found that patients with DCS (54.81 ± 13.3) were older than non-DCS patients (43.71 ± 12.94) which was statistically significant (p < 0.05). There was statistically no correlation between the severity of CR and CTS, ipsilaterlly (p > 0.05). In total, CTS was observed in 62.2% (n = 181) patients.

Conclusion

In summary, we found a relatively high prevalence of DCS in the present study. In patients with and without DCS, gender did not seem to play a role but the growing age seemed to contribute to DCS. The severity of CTS was not related to CR severity at any cervical level, which negates a causal relation between the pre-existing CR and newly diagnosed CTS.

Double Crush Syndrome of the Lower Limb in L5 Radiculopathy and Peroneal Neuropathy: A Case Report

Double crush syndrome (DCS) is a clinical condition involving impingement of the spinal and peripheral nerves. DCS of the lower limbs has been recognized; however, no detailed reports have been published. Herein, we report a rare case of the coexistence of L5 radiculopathy and peroneal nerve entrapment neuropathy. The patient suffered from pain in the left lower leg and left foot combined with muscle weakness in the left leg without a Tinel-like sign in the peroneal tunnel area. MRI showed a deficit in the left L5 nerve root sleeve, and X-ray imaging revealed L5 spondylolysis. Lumbar fusion surgery was performed at L5-S1. Subsequently, the patient’s symptoms were partially improved, but the pain and toe and ankle motor weakness persisted. In addition, a Tinel-like sign appeared at the entrapment point of the peroneal nerve. The entrapped peroneal nerve was decompressed, and the patient’s symptoms improved. The patient had L5 radiculopathy owing to the improvement in his symptoms in the upper leg before and after lumbar surgery. It is unclear why no Tinel-like sign was detected before the first surgery, but we hypothesized that L5 nerve disorder may mask the symptoms triggered by compression of the peroneal nerve due to the complex pathology of DCS and dynamic factors. Distinguishing between radiculopathy and relative peripheral neuropathy should always be a consideration. DCS may mask characteristic symptoms, and it is important to carefully follow up the patient to detect changes in his or her condition.

The Myth of Median Nerve in Forearm and Its Role in Double Crush Syndrome: A Cadaveric Study

Purpose: This study aims to histologically compare the median nerve in the arm, forearm, and wrist, to help understand how cervical radiculopathy in a double crush phenomenon causes distal nerve dysfunction at the carpal tunnel and median nerve with concurrent absence of symptoms at the forearm.

Methods: The study was performed on 12 fresh cadaveric upper limbs free from any injury or operation. Male cadavers in the age range of 35–40 years were used. The dissection of the median nerve and the histological examination of the specimens from the arm, forearm, and wrist were conducted to evaluate variations in the epineurium thickness (μm), perineurium thickness (μm), number of fascicles per nerve trunk, area percent of myelin covering, and area percent of neurolemmal sheath.

Results: Morphometric and statistical results of the cadaveric median nerve trunk revealed that the mean epineurium and perineurium thickness measured in H&E-stained sections in the forearm were significantly greater than those in the arm and wrist specimens. Further, the mean percent area of the myelin covering in the forearm was significantly lower than that in the arm and wrist specimens in the sections stained with osmium oxide (p < 0.001). There were, however, no significant differences in the neurolemmal sheath among the arm, forearm, and wrist specimens in the silver-stained sections.

Conclusion: The histological differences explained the high concomitant occurrence of carpal tunnel syndrome (CTS) and cervical radiculopathy and the concurrent absence of symptoms at the forearm. Hence, we suggest cautious evaluation of patients with upper limb symptoms, since the management of these conditions requires a different approach.

Possible Double Crush Syndrome Caused by Iatrogenic Acquired Lumbosacral Epidermoid Tumor and Concomitant Sacral Tarlov Cyst

We describe a rare case of 42-year-old female who had possible double crush syndrome caused by iatrogenic spinal epidermoid tumor (ET) associated with lumbar puncture as well as concomitant sacral Tarlov cyst in close proximity. She presented with progressive left-sided perianal pain. She had a history of a Caesarean section with lumbar spinal anesthesia. Magnetic resonance imaging (MRI) demonstrated a relatively small intradural extramedullary solid lesion at L5/S1 level and cystic lesion at S2 level. We considered there were two different lesions, such as a tumor and Tarlov cyst; however, we could not rule out the possibility of a single lesion with two different components. Furthermore, there was a distinct compression at more than one locations along the course of the left S2 nerve root and we suspected possible double crush syndrome. We conducted tumor removal and the lesion turned out to be two different pathologies, such as an ET and Tarlov cyst. Both lesions were intraopertively pinching the left S2 nerve root at different sites as expected. The tumor was successfully removed and the cyst wall was imbricated and sutured. We need to take the possibility of ET into consideration if the patient underwent invasive spinal procedure previously. We also have to pay attention to the possibility of double crush syndrome if the nerve root possibly holding the responsibility for symptoms is compressed at two or more sites. This is the first report of possible double crush syndrome caused by acquired spinal tumor and congenital Tarlov cyst.

Role of fasciae around the median nerve in pathogenesis of carpal tunnel syndrome: microscopic and ultrasound study

This study investigated the connections between the median nerve paraneural sheath and myofascial structures near it, from both macroscopic and microscopic points of view. Four samples of median nerve and surrounding tissues were excised from nine non-embalmed upper limbs for microscopic analysis. Ultrasound images were analysed in 21 healthy subjects and 16 carpal tunnel syndrome patients to evaluate median nerve transversal displacement during finger motion at carpal tunnel and forearm levels. An anatomical continuity between epimysium and paraneural sheath and a reduction of paraneural fat tissue from proximal to distal was found in all samples. Median nerve displacements at both levels were significantly reduced in carpal tunnel syndrome subjects (P < 0.001). It was observed that the median nerve is not an isolated structure but is entirely connected to myofascial structures. Therefore, unbalanced tension of epimysial fasciae can affect the paraneural sheath, limiting nerve displacement, and consequently this must be included in carpal tunnel syndrome pathogenesis.

Nerve ultrasound identifies abnormalities in the posterior interosseous nerve in patients with proximal radial neuropathies

INTRODUCTION

The radial nerve and posterior interosseous nerve (PIN) are prone to injury at multiple sites. Electrodiagnostic (EDx) studies may only identify the most proximal lesion. Nerve ultrasound could augment EDx by visualizing additional pathology.

METHODS

This investigation was a retrospective examination of ultrasound and EDx from 26 patients evaluated for posterior cord/radial/PIN lesions.

RESULTS

Eighteen of 26 patients had abnormalities on EDx (15 radial, 2 PIN, 1 posterior cord). Ultrasound identified 15 of 18 (83%) of the EDx abnormalities and provided additional diagnostic information. In 6 of 15 (40%) patients with EDx evidence of radial neuropathy, ultrasound identified both radial nerve enlargement and additional, unsuspected PIN enlargement (53% to 339% enlarged vs. unaffected side). Ultrasound also identified: nerve (dis)continuity at the trauma site (n = 8); and nerve tumor (n = 2; 1 with normal EDx).

CONCLUSION

In radial neuropathy, ultrasound often augments EDx studies and identifies a second lesion in the PIN. Further studies are required to determine the etiology and significance of this additional distal pathology.

Florid Suprascapular Neuropathy after Primary Rotator Cuff Repair Attributed to Suprascapular Notch Constriction in the Setting of Double Crush Syndrome

This report describes a patient who had an open repair of a small supraspinatus tendon tear performed 6 months after an arthroscopic acromioplasty with debridement had failed to provide pain relief. Three months prior to the tendon repair, he had a two-level cervical spine discectomy and fusion (C4-5, C5-6) that improved his neck pain. Florid suprascapular neuropathy was detected 10 weeks after the open rotator cuff repair. Evidence of some nerve recovery resulted in a long period of observation. But unsatisfactory improvement warranted decompression of the suprascapular notch, which was found to be very stenotic. At surgery, there was no evidence of neuroma, cyst, or other compressing lesion or tissue. Therefore, it was ultimately hypothesized that there was an exacerbation of a preexisting, but clinically unrecognized, entrapment of the suprascapular nerve in the suprascapular notch in the setting of cervical radiculopathy (primarily C5). Retrospectively it was also concluded that had this compressive etiology been recognized, it would have favored prompt decompression rather than the long observation period. Three years was required to achieve a good result following suprascapular notch decompression. The underlying C5 radiculopathy may have created a "double crush syndrome" that contributed to the propensity for injury and the prolonged recovery. There should be heightened awareness of this problem in patients who do not have satisfactory improvement in shoulder pain from previous shoulder and neck surgery.

Spectrum of suprascapular nerve lesions: normal and abnormal neuromuscular imaging appearances on 3-T MR neurography. AJR Am J Roentgenol. 2015;204:589-601. [PMID: 25714290 DOI: 10.2214/ajr.14.12974]

OBJECTIVE. In this article, we will review the normal anatomy and imaging features of various neuromuscular abnormalities related to suprascapular neuropathy. CONCLUSION. Suprascapular neuropathy can be difficult to distinguish from rotator cuff pathology, plexopathy, and radiculopathy. Electrodiagnostic studies are considered the reference standard for diagnosis; however, high-resolution 3-T MR neurography (MRN) can play an important role. MRN enables direct visualization of the nerve and simultaneous assessment of the cervical spine, brachial plexus, and rotator cuff.

Spectrum of suprascapular nerve lesions: normal and abnormal neuromuscular imaging appearances on 3-T MR neurography

OBJECTIVE. In this article, we will review the normal anatomy and imaging features of various neuromuscular abnormalities related to suprascapular neuropathy. CONCLUSION. Suprascapular neuropathy can be difficult to distinguish from rotator cuff pathology, plexopathy, and radiculopathy. Electrodiagnostic studies are considered the reference standard for diagnosis; however, high-resolution 3-T MR neurography (MRN) can play an important role. MRN enables direct visualization of the nerve and simultaneous assessment of the cervical spine, brachial plexus, and rotator cuff.

Double crush syndrome due to plating of humeral shaft fracture

Median nerve injury is rarely associated with the humeral shaft fracture. A Sixty two year old woman with a displaced humeral shaft fracture, developed a symptomatic carpal tunnel syndrome after plating with a screw protruding medially. 16 months later, the implants were removed and the symptoms gradually improved without carpal tunnel release surgery. A double crush syndrome resulted due to the proximal compression by the medially protruding screw and the distal compression by carpal tunnel. The proximal decompression produced by removal of the screw led to relief of the symptoms.

Case report: Myofascial pain syndrome: a double crush-like appearance

OBJECTIVE

To discuss the case of a patient with myofascial pain syndrome that appeared similar to double crush syndrome.

CLINICAL FEATURES

This is a case report of a 45-year old female who presents to the private practice clinic with the same signs and symptoms of carpal tunnel syndrome, 1 year post-carpaltunnel surgery. The history is consistent with injuries that result in double crush syndrome and thoracic outlet syndrome. The patient history includes a motor vehicle accident (MVA) in 1963 that resulted in a prolonged hospital stay and fracture of a cervical vertebral (C4) body. She fractured the olecranon process of the right elbow during a fall in 1970's. She has smoked approximately 1 pack a day for 20 years. Her job involves long periods of sitting at a keyboard and in a car. All of these portions of the patient history are possible factors in the clinical signs and symptoms of double crush syndrome.

INTERVENTION AND OUTCOME

Treatment involved chiropractic manipulation and physical therapy modalities for the elimination of pain and returning the patient's full range of motion in the wrist, elbow, shoulder and cervical spine. After range of motion was restored, a home exercise program was initiated. The home exercise program included a return to past sporting activity and active, resistive (Theraciser band) activities for the elbow and cervical spine. Also a reduction in smoking was initiated as part of the patient's treatment plan.

CONCLUSION

It is our contention that patients who have electromyographic (EMG) demonstrable carpal tunnel syndrome need a cervical spine workup and a period of conservative care to include skilled manipulation, physical therapy and home exercises before surgery is recommended.