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Peripheral nerve injury grading simplified on MR neurography: As referenced to Seddon and Sunderland classifications.

Chhabra A, Ahlawat S, Belzberg A, Andreseik G - Indian J Radiol Imaging (2014)

Bottom Line: The Seddon and Sunderland classifications have been used by physicians for peripheral nerve injury grading and treatment.While Seddon classification is simpler to follow and more relevant to electrophysiologists, the Sunderland grading is more often used by surgeons to decide when and how to intervene.With increasing availability of high-resolution and high soft-tissue contrast imaging provided by MR neurography, the surgical treatment can be guided following the above-described grading systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Orthopaedic Surgery, University of Texas Southwestern Medical Center, Baltimore, MD, USA.

ABSTRACT
The Seddon and Sunderland classifications have been used by physicians for peripheral nerve injury grading and treatment. While Seddon classification is simpler to follow and more relevant to electrophysiologists, the Sunderland grading is more often used by surgeons to decide when and how to intervene. With increasing availability of high-resolution and high soft-tissue contrast imaging provided by MR neurography, the surgical treatment can be guided following the above-described grading systems. The article discusses peripheral nerve anatomy, pathophysiology of nerve injury, traditional grading systems for classifying the severity of nerve injury, and the role of MR neurography in this domain, with respective clinical and surgical correlations, as one follows the anatomic paths of various nerve injury grading systems.

No MeSH data available.


Related in: MedlinePlus

Nerve root lacerations/Sunderland grade V Injury. A 25 year old man, status post motor vehicle accident, suffered spine injury and multiple injuries to the right shoulder region including clavicle fracture which required internal fixation and trapezius muscle tear. The patient was noted to have right brachial plexus injury on clinical assessment, with flail right extremity and Horner's syndrome. EMG was performed 2 months after the initial injury which demonstrated lack of motor units in the right C5 through T1 nerve root distribution. Although not definitive on clinical exam or EMG, avulsion injury was suspected due to the presence of Horner's syndrome. MRN was performed 3 months after the initial injury. MIP reconstruction from coronal 3D STIR SPACE demonstrates complete discontinuity of the right brachial plexus (large arrow) with bundling of the lacerated nerve roots and trunks (medium arrow) in the right axilla. Intraoperative electrophysiology confirmed lack of conduction in the enlarged right C5 nerve root (double small arrows), lacerated distally
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Figure 9: Nerve root lacerations/Sunderland grade V Injury. A 25 year old man, status post motor vehicle accident, suffered spine injury and multiple injuries to the right shoulder region including clavicle fracture which required internal fixation and trapezius muscle tear. The patient was noted to have right brachial plexus injury on clinical assessment, with flail right extremity and Horner's syndrome. EMG was performed 2 months after the initial injury which demonstrated lack of motor units in the right C5 through T1 nerve root distribution. Although not definitive on clinical exam or EMG, avulsion injury was suspected due to the presence of Horner's syndrome. MRN was performed 3 months after the initial injury. MIP reconstruction from coronal 3D STIR SPACE demonstrates complete discontinuity of the right brachial plexus (large arrow) with bundling of the lacerated nerve roots and trunks (medium arrow) in the right axilla. Intraoperative electrophysiology confirmed lack of conduction in the enlarged right C5 nerve root (double small arrows), lacerated distally

Mentions: Type IV injury manifests as a neuroma-in-continuity, which is seen as focal fusiform nerve enlargement with or without underlying diffuse long segment enlargement. Fascicular discontinuity and focally enlarged nerve with heterogeneous signal is the key to differentiate grade IV injury from grade III injury, where the nerve is homogeneous with fascicular continuity. Grade III injury should be distinguished from grade IV and V injuries for timely surgical management of the latter injuries. Neuroma-in-continuity shows heterogeneous signal abnormality due to internal hemorrhage and fibrosis [Figure 7]. It usually shows no significant enhancement as compared to peripheral nerve sheath tumor, which shows classic imaging signs (target, fascicular) and commonly enhances with intravenous contrast.[10] In suspected neuroma-in-continuity on imaging with no clear history of trauma, one should perform contrast MRN to exclude a peripheral nerve sheath tumor or other mass lesion. 3D isotropic imaging is often very useful in demonstrating neuroma-in-continuity (grade IV injury) and neurotmesis (grade V injury) for the reader and the referring physicians alike. Nerve discontinuity in grade V injury shows a clear nerve gap or intervening hemorrhage and/or fibrosis [Figures 8 and 9]. The proximal nerve segments show end-bulb neuromas.[9] One of the key roles of imaging is to measure the gap between the proximal and distal discontinuous nerve fragments for the purpose of operative management. The radiologist can play an important role in accurately diagnosing Sunderland V injury in a functionally important nerve and inform the surgeon about the length of the gap so that appropriate dimension allograft or autograft can be prepared prior to nerve repair. Therefore, close interrogation with high-resolution imaging to correctly identify abnormalities is essential for treatment planning.[2930] Identification of pseudomeningocele does not always mean dorsal nerve root ganglion avulsion as the pre-ganglionic segments may be partially intact.[31] Therefore, it is important to look at 3D T2W TSE imaging to evaluate the integrity of preganglionic nerve segments and position of dorsal nerve root ganglions. Finally, chronic neuropathy results in atrophic nerve with decreased nerve caliber and relatively increased intra-epineurial fat deposition with atrophic appearance of the fascicles.[32]


Peripheral nerve injury grading simplified on MR neurography: As referenced to Seddon and Sunderland classifications.

Chhabra A, Ahlawat S, Belzberg A, Andreseik G - Indian J Radiol Imaging (2014)

Nerve root lacerations/Sunderland grade V Injury. A 25 year old man, status post motor vehicle accident, suffered spine injury and multiple injuries to the right shoulder region including clavicle fracture which required internal fixation and trapezius muscle tear. The patient was noted to have right brachial plexus injury on clinical assessment, with flail right extremity and Horner's syndrome. EMG was performed 2 months after the initial injury which demonstrated lack of motor units in the right C5 through T1 nerve root distribution. Although not definitive on clinical exam or EMG, avulsion injury was suspected due to the presence of Horner's syndrome. MRN was performed 3 months after the initial injury. MIP reconstruction from coronal 3D STIR SPACE demonstrates complete discontinuity of the right brachial plexus (large arrow) with bundling of the lacerated nerve roots and trunks (medium arrow) in the right axilla. Intraoperative electrophysiology confirmed lack of conduction in the enlarged right C5 nerve root (double small arrows), lacerated distally
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126136&req=5

Figure 9: Nerve root lacerations/Sunderland grade V Injury. A 25 year old man, status post motor vehicle accident, suffered spine injury and multiple injuries to the right shoulder region including clavicle fracture which required internal fixation and trapezius muscle tear. The patient was noted to have right brachial plexus injury on clinical assessment, with flail right extremity and Horner's syndrome. EMG was performed 2 months after the initial injury which demonstrated lack of motor units in the right C5 through T1 nerve root distribution. Although not definitive on clinical exam or EMG, avulsion injury was suspected due to the presence of Horner's syndrome. MRN was performed 3 months after the initial injury. MIP reconstruction from coronal 3D STIR SPACE demonstrates complete discontinuity of the right brachial plexus (large arrow) with bundling of the lacerated nerve roots and trunks (medium arrow) in the right axilla. Intraoperative electrophysiology confirmed lack of conduction in the enlarged right C5 nerve root (double small arrows), lacerated distally
Mentions: Type IV injury manifests as a neuroma-in-continuity, which is seen as focal fusiform nerve enlargement with or without underlying diffuse long segment enlargement. Fascicular discontinuity and focally enlarged nerve with heterogeneous signal is the key to differentiate grade IV injury from grade III injury, where the nerve is homogeneous with fascicular continuity. Grade III injury should be distinguished from grade IV and V injuries for timely surgical management of the latter injuries. Neuroma-in-continuity shows heterogeneous signal abnormality due to internal hemorrhage and fibrosis [Figure 7]. It usually shows no significant enhancement as compared to peripheral nerve sheath tumor, which shows classic imaging signs (target, fascicular) and commonly enhances with intravenous contrast.[10] In suspected neuroma-in-continuity on imaging with no clear history of trauma, one should perform contrast MRN to exclude a peripheral nerve sheath tumor or other mass lesion. 3D isotropic imaging is often very useful in demonstrating neuroma-in-continuity (grade IV injury) and neurotmesis (grade V injury) for the reader and the referring physicians alike. Nerve discontinuity in grade V injury shows a clear nerve gap or intervening hemorrhage and/or fibrosis [Figures 8 and 9]. The proximal nerve segments show end-bulb neuromas.[9] One of the key roles of imaging is to measure the gap between the proximal and distal discontinuous nerve fragments for the purpose of operative management. The radiologist can play an important role in accurately diagnosing Sunderland V injury in a functionally important nerve and inform the surgeon about the length of the gap so that appropriate dimension allograft or autograft can be prepared prior to nerve repair. Therefore, close interrogation with high-resolution imaging to correctly identify abnormalities is essential for treatment planning.[2930] Identification of pseudomeningocele does not always mean dorsal nerve root ganglion avulsion as the pre-ganglionic segments may be partially intact.[31] Therefore, it is important to look at 3D T2W TSE imaging to evaluate the integrity of preganglionic nerve segments and position of dorsal nerve root ganglions. Finally, chronic neuropathy results in atrophic nerve with decreased nerve caliber and relatively increased intra-epineurial fat deposition with atrophic appearance of the fascicles.[32]

Bottom Line: The Seddon and Sunderland classifications have been used by physicians for peripheral nerve injury grading and treatment.While Seddon classification is simpler to follow and more relevant to electrophysiologists, the Sunderland grading is more often used by surgeons to decide when and how to intervene.With increasing availability of high-resolution and high soft-tissue contrast imaging provided by MR neurography, the surgical treatment can be guided following the above-described grading systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Orthopaedic Surgery, University of Texas Southwestern Medical Center, Baltimore, MD, USA.

ABSTRACT
The Seddon and Sunderland classifications have been used by physicians for peripheral nerve injury grading and treatment. While Seddon classification is simpler to follow and more relevant to electrophysiologists, the Sunderland grading is more often used by surgeons to decide when and how to intervene. With increasing availability of high-resolution and high soft-tissue contrast imaging provided by MR neurography, the surgical treatment can be guided following the above-described grading systems. The article discusses peripheral nerve anatomy, pathophysiology of nerve injury, traditional grading systems for classifying the severity of nerve injury, and the role of MR neurography in this domain, with respective clinical and surgical correlations, as one follows the anatomic paths of various nerve injury grading systems.

No MeSH data available.


Related in: MedlinePlus