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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

Sunderland grade III injury. Intraoperative image demonstrates shot gun fragment (small arrow) in the exposed swollen median nerve following epineurotomy. Notice intact nerve fascicles (long arrow)
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Figure 2: Sunderland grade III injury. Intraoperative image demonstrates shot gun fragment (small arrow) in the exposed swollen median nerve following epineurotomy. Notice intact nerve fascicles (long arrow)

Mentions: Sir Sydney Sunderland[7] described five degrees of peripheral nerve injury [Table 1]. The first degree corresponds to neurapraxia and the second degree to axonotmesis as described above. The third, fourth, and fifth degrees involve injury to endoneurial tubes, perineurium, and epineurium, respectively. In these injuries, since the connective tissue sheaths are disrupted, the regenerating axons are misdirected and may not be able to innervate the sensory endings or muscle end plates, and the pattern of recovery indicated by muscle unit potentials is mixed and, often, incomplete. More retrograde degeneration occurs in third-degree injury as compared to second-degree injury and the fascicular continuity is still maintained [Figure 2]. While recovery usually occurs in the third-degree injury over many months with conservative treatment, surgical intervention may be required to release the entrapment sites over the swollen nerve with or without limited neurolysis. In the fourth-degree injury, internal hemorrhage and fibrous tissue entangles the regenerating and growing nerve sprouts due to fascicular discontinuity, inhibiting the directed distal axonal growth, thereby resulting in the formation of neuroma-in-continuity. Fifth-degree injury leads to complete nerve discontinuity and formation of end-bulb neuroma [Figure 3]. In these two injuries, Tinel sign fails to advance beyond the level of injury and no muscle unit potentials are observed. Electrophysiology studies cannot differentiate fourth-degree injury from fifth-degree injury and not much functional recovery is expected without surgery. Since fibrosis may occur diffusely or focally within a neuroma-in-continuity, the involved segment may still conduct action potentials among preserved axons and produce minimal muscular contractions upon stimulation. Internal neurolysis with careful dissection may enhance nerve regeneration. However, this may also lead to further scarring. On the other hand, in case of absence of nerve conduction, neuroma resection and grafting across the nerve defect or damaged parts of the nerve offer acceptable chances of functional recovery. When excessive length of the nerve gap or timing of regeneration preclude grafting, nerve transfer may be employed to optimize recovery. In case of definite nerve gap, proximal and distal nerve stumps may be realigned using epineurial or perineurial sutures, with fibrin glue reinforcement. This technique is usually reserved for very distal repairs and coaptation under tension should be avoided by employing other methods of surgical repair.[16]


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)

Sunderland grade III injury. Intraoperative image demonstrates shot gun fragment (small arrow) in the exposed swollen median nerve following epineurotomy. Notice intact nerve fascicles (long arrow)
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Sunderland grade III injury. Intraoperative image demonstrates shot gun fragment (small arrow) in the exposed swollen median nerve following epineurotomy. Notice intact nerve fascicles (long arrow)
Mentions: Sir Sydney Sunderland[7] described five degrees of peripheral nerve injury [Table 1]. The first degree corresponds to neurapraxia and the second degree to axonotmesis as described above. The third, fourth, and fifth degrees involve injury to endoneurial tubes, perineurium, and epineurium, respectively. In these injuries, since the connective tissue sheaths are disrupted, the regenerating axons are misdirected and may not be able to innervate the sensory endings or muscle end plates, and the pattern of recovery indicated by muscle unit potentials is mixed and, often, incomplete. More retrograde degeneration occurs in third-degree injury as compared to second-degree injury and the fascicular continuity is still maintained [Figure 2]. While recovery usually occurs in the third-degree injury over many months with conservative treatment, surgical intervention may be required to release the entrapment sites over the swollen nerve with or without limited neurolysis. In the fourth-degree injury, internal hemorrhage and fibrous tissue entangles the regenerating and growing nerve sprouts due to fascicular discontinuity, inhibiting the directed distal axonal growth, thereby resulting in the formation of neuroma-in-continuity. Fifth-degree injury leads to complete nerve discontinuity and formation of end-bulb neuroma [Figure 3]. In these two injuries, Tinel sign fails to advance beyond the level of injury and no muscle unit potentials are observed. Electrophysiology studies cannot differentiate fourth-degree injury from fifth-degree injury and not much functional recovery is expected without surgery. Since fibrosis may occur diffusely or focally within a neuroma-in-continuity, the involved segment may still conduct action potentials among preserved axons and produce minimal muscular contractions upon stimulation. Internal neurolysis with careful dissection may enhance nerve regeneration. However, this may also lead to further scarring. On the other hand, in case of absence of nerve conduction, neuroma resection and grafting across the nerve defect or damaged parts of the nerve offer acceptable chances of functional recovery. When excessive length of the nerve gap or timing of regeneration preclude grafting, nerve transfer may be employed to optimize recovery. In case of definite nerve gap, proximal and distal nerve stumps may be realigned using epineurial or perineurial sutures, with fibrin glue reinforcement. This technique is usually reserved for very distal repairs and coaptation under tension should be avoided by employing other methods of surgical repair.[16]

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