Sonographic evaluation of peripheral nerve pathology in the emergency setting

The role of preoperative ultrasound in the management of peripheral nerve injuries

BACKGROUND

Peripheral nerve injury refers to any damage or trauma to the nerves located outside the central nervous system. Ultrasonography is a reliable, cheap, and minimally invasive method in clinical practice to give physicians useful information about nerve injury.

OBJECTIVES

to assess the power of ultrasound in determining the presence, localization, and extent of neural damage in patients with clinical evidence of peripheral nerve lesions before surgery.

METHODS

This cross-sectional study was conducted on 78 patients (56 females and 22 males, aged from 9 to 52 years) who had different pathologies including entrapment, tumoral, post-traumatic, and post-surgical nerve injuries at the Neurosurgery and Physical Medicine, Rheumatology, and Rehabilitation Departments, Tanta University Hospitals. All studied patients had preoperative evaluation; neurological examination, electrodiagnostic studies, and sonographic examinations with linear array transducers (frequencies ranging from 7.5 to 16 MHz).

RESULTS

The most common pathological condition was entrapment neuropathy (39 patients) (50%). Ultrasound complemented the electrodiagnostic studies by determining the site of entrapment manifested by increased mean maximum cross-sectional area of the nerve proximal to the site of entrapment and nerve hypoechogenicity. In post-traumatic and iatrogenic neuropathies (35 patients) (44.9%), the ultrasound finding revealed neuroma in continuity in nine cases (11.5%), complete neurotmesis with stump neuroma in eighteen patients (23.1%), and eight cases (10.3%) showed perineural adhesion. In all cases, the nerve was hypoechoic at the site of injury. The presence of hyperechoic fibrous tissue could indicate perineural adhesion and the necessity for neurolysis. This study also included three (3.8%) cases had schwannoma, and one case (1.3%) had neurofibroma. Ultrasound was used to confirm the diagnosis by determining the tumor's size and vascular supply.

CONCLUSIONS

Ultrasonography is a diagnostic and surgical planning tool that is becoming more and more useful for the management of peripheral nerve injuries. Its high resolution and real-time capability provide safe and cost-effective scans that aid in determining the extent of injuries. For patients with peripheral nerve injuries, ultrasound is advised to be added to the routine clinical and neurophysiological evaluation. It is also advised to use ultrasound as a first-line imaging modality for tumors thought to be of nerve origin.

Value of ultrasound assessment for traumatic nerve injury of the upper limb

Aim of work

The type of traumatic peripheral nerve injury is a key factor for determining optimal treatment. Proper assessment of peripheral nerve injury facilitates appropriate treatment, significantly affects prognosis, and reduces disabilities. This study evaluated ultrasonography (US) to assess upper limb traumatic nerve injuries and compared the US with electrodiagnostic studies as the gold standard.

Materials and Methods

Participants were 69 adults (57 [83%] men, 12 [17%] women; mean age 36.3 ± 13.5 years) with a total of 96 peripheral nerve injuries (duration of 1 month–3 years). High-frequency US examinations and electro-physiologic studies confirmed upper limb peripheral nerve injury.

Results

Nerve discontinuation was diagnosed in 15 (15.6%) nerves; the cross-sectional area was increased in 33 (34.4%) nerves. Of 96 injuries, 54 (56.3%) were median, 24 (25%) were ulnar, and 18 (18.8%) were radial nerves. No statistically significant difference was found between US and electro-physiologic studies for nerve injury diagnosis (p = 0.054).

Conclusion

No significant differences were found between US and electro-physiologic studies for diagnosis of nerve injuries; however, US was valuable to assess surrounding tissue and supplied muscles. The capabilities to detect nerve injury and associated distal muscular, vascular, and other regional structures position the US as a complementary diagnostic tool.

The accuracy of routine knee MR imaging in detection of acute neurovascular injury following multiligamentous knee injury

OBJECTIVE

To assess the accuracy of routine knee MRI in detecting acute popliteal artery and/or common peroneal nerve (CPN) dysfunction following multiligamentous knee injury (MLKI), with correlation of MRI findings to clinical outcome.

MATERIALS AND METHODS

Routine MRI knee examinations in 115 MLKI patients (54/115 with acute neurovascular injury, 61/115 without neurovascular injury) were retrospectively reviewed. Cases were classified by injury mechanism and ligamentous injuries sustained. MRI examinations were reviewed by two readers for vascular (arterial flow void, arterial calibre, intimal flap, perivascular hematoma) and CPN (intraneural T2-hyperintensity, calibre, discontinuity, perineural hematoma) injuries. Accuracy of routine knee MRI in the diagnosis of acute neurovascular injury and correlation of MRI findings to clinical outcome were evaluated.

RESULTS

Patients included 86/115 males, mean age 33 years. The accuracy of MRI in diagnosis of acute CPN injury was 80.6%, 83.6% (readers 1 and 2): sensitivity (78%, 79.7%), specificity (80%, 86.7%), PPV (78%, 82.5%), and NPV (82.7%, 84.4%). Increased intraneural T2 signal showed a significant correlation to acute CPN dysfunction (p < 0.05). MRI was 75%, 69.8% (readers 1 and 2) accurate in detecting acute vascular injury: sensitivity (73.3%, 86.7%), specificity (75.2%, 67.3%), PPV (30.5%, 36.1%), and NPV (95%, 97.1%). No MRI features of vascular injury showed a statistical correlation with clinical outcome. Neurovascular complications were more common in ultra-low-energy injuries and KD-V3L pattern of ligament disruption.

CONCLUSION

Routine MRI is of limited accuracy in assessing vascular complication, but higher accuracy in assessing CPN injury following MLKI. Increased intraneural T2 signal on conventional knee MR imaging shows statistically significant association with clinically documented acute CPN dysfunction following MLKI.

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part I: Extraarticular Pathologies

The first part of the guidelines and recommendations for musculoskeletal ultrasound, produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), provides information about the use of musculoskeletal ultrasound for assessing extraarticular structures (muscles, tendons, entheses, ligaments, bones, bursae, fasciae, nerves, skin, subcutaneous tissues, and nails) and their pathologies. Clinical applications, practical points, limitations, and artifacts are described and discussed for every structure. After an extensive literature review, the recommendations have been developed according to the Oxford Centre for Evidence-based Medicine and GRADE criteria and the consensus level was established through a Delphi process. The document is intended to guide clinical users in their daily practice.

Intraosseous Type 2 Median Nerve Entrapment After Posterior Elbow Dislocation Diagnosed on Ultrasound With MRI and Surgical Correlation

Median nerve entrapment is a rare complication of posterior elbow dislocation and medial epicondyle fracture. In the event of delayed diagnosis, this injury pattern may result in significant and sometimes irreversible nerve damage. As such, a high degree of clinical suspicion and early imaging is indicated in patients with persistent nerve deficits following reduction of elbow dislocation.

Here, a case of intraosseous type 2 median nerve entrapment that was diagnosed on ultrasound in an eight-year-old patient following ulnohumeral dislocation is discussed. This article reviews the key imaging findings of median nerve entrapment and discusses the subsequent MRI and surgical findings of this rare condition.

Traumatic Injuries to the Spinal Cord and Peripheral Nervous System

Both blunt and penetrating trauma can cause injuries to the peripheral and central nervous systems. Emergency providers must maintain a high index of suspicion, especially in the setting of polytrauma. There are 2 major classifications of peripheral nerve injuries (PNIs). Some PNIs are classically associated with certain traumatic mechanisms. Most closed PNIs are managed conservatively, whereas sharp nerve transections require specialist consultation for urgent repair. Spinal cord injuries almost universally require computed tomography imaging; some require emergent magnetic resonance imaging. Providers should work to minimize secondary injury. Surgical specialists are needed for closed reduction, surgical decompression, or stabilization.

Role of nerve ultrasound versus electrophysiological studies in the evaluation of nerve injuries

Background

High-resolution ultrasonography (US) is a non-invasive, readily applicable imaging modality capable of depicting real-time static and dynamic information concerning the peripheral nerves and their surrounding tissues. Although electrophysiological studies are the gold standard in the evaluation of nerve injuries, US can be used also to evaluate the morphological changes of nerve injuries.

Objectives

To evaluate the role of the high-resolution US in the assessment of nerve injuries and to compare it to the role of electrodiagnostic studies.

Subjects and methods

A total of 30 nerves from 22 consecutive patients with clinically definite nerve injury were considered. Two independent and blinded clinicians perform electrodiagnosis and US. The clinical, neurophysiological, and US findings were collected, and the contribution of US was then classified as “ contributive” or “non-contributive”, according to whether US confirmed the clinical and neurophysiological diagnosis or not.

Results

US was “contributive” (confirming the electrophysiological diagnosis) in 66.67% of cases (n = 20), providing information about continuity of the nerve, morphological changes after injury as swelling, scar tissue formation, or neuroma formation with sensitivity of 75% compared to the electrodiagnostic studies and accuracy of 66.67%.

Conclusion

Ultrasound can be used, when available, as a complementary tool for electrodiagnostic studies to provide anatomical information about the injured nerves in case of complete axonal lesion.

The progress of biomaterials in peripheral nerve repair and regeneration

Repair and regeneration of the injured peripheral nerve (PN) is a challenging issue in clinics. Although the regeneration outcome of large PN defects is currently unsatisfactory, recently, the study of PN repair has considerably progressed. In particular, biomaterials for repairing PNs, such as nerve guidance conduits and nerve repair membranes, have been well developed. Herein, we summarize the anatomy of the PN, the pathophysiological features of the nerve injury, and the repair process post injury. Then, we highlight the progress in the development of natural and synthetic biomaterials and summarize the applications, advantages, and disadvantages of these materials. These materials can be used as nerve repair membranes and nerve conduits in the field of PN repair. Finally, we discuss the challenges encountered and development strategies for PN repair in the future.

A rare case of type 2 entrapment of the median nerve after posterior elbow dislocation with MRI and ultrasound correlation

A 9-year-old boy sustained an ulnohumeral dislocation with a medial epicondyle fracture and experienced incomplete post-traumatic median nerve palsy in addition to post-traumatic stiffness following closed reduction and cast immobilization. When his motor palsy and stiffness did not improve, MRI and ultrasound were obtained, which demonstrated entrapment of the median nerve in an osseous tunnel at the fracture site, compatible with type 2 median nerve entrapment. Subsequently, the patient underwent surgery to mobilize the medial epicondyle and free the median nerve, resulting in improved range of motion, near complete restoration of motor function, and complete restoration of sensory function in the median nerve distribution within 6 months of surgery. Median nerve entrapment, particularly intraosseous, is a rare complication of posterior elbow dislocation and medial epicondyle fracture that may result in significant, sometimes irreversible, nerve damage if there is a delay in diagnosis and treatment. A high degree of clinical suspicion with early imaging is indicated in patients with persistent stiffness or nerve deficits following reduction of an elbow dislocation. Intra-articular entrapment diagnosed on ultrasound has been reported and intraosseous entrapment diagnosed clinically and on MR neurography have been reported; however, to our knowledge, this is the first reported case of intraosseous (type 2) median nerve entrapment clearly visualized and diagnosed on traditional MRI and ultrasound. The use of ultrasound for diagnosing median nerve entrapment is an accurate, accessible, and non-invasive imaging option for patients presenting with suspected nerve entrapment following elbow dislocation.