eMedicine Specialties > Neurology > Neuromuscular Diseases
Traumatic Peripheral Nerve Lesions: Multimedia
Updated: Oct 11, 2006
Multimedia
 | Media file 1: A 58-year-old woman with a tender right neck mass had paraesthesias radiating to her distal right arm, with preoperative electrodiagnostic test results interpreted as consistent with severe axonal loss (Case study 1). Postoperative right arm pain and weakness did not improve with time, and the patient was taken back to the operating room. Large-amplitude compound muscle action potential (CMAP) response was recorded from the right biceps muscle after intraoperative direct bipolar stimulation of the proximal right musculocutaneous nerve at low stimulus intensities (3.9 mA). The time base shown is 10 milliseconds/div and the gain is 50 mcV/div. |
 | Media file 2: A 55-year-old man experienced pain and numbness in his right hand after prolonged laparotomy (Case study 2). Electrodiagnostic testing 1 day after the injury revealed the following: (Left) Right ulnar motor conduction study showed a normal distal amplitude with conduction block across the elbow segment (gain = 2 mV/div, time base = 2 milliseconds [ms]/div). (Second from left) Right ulnar sensory response was normal (gain = 20 mcV/div, time base = 2 ms/div). (Third from left) Right ulnar F-wave responses were absent. (Right) Needle electromyographic (EMG) examination of right abductor digiti minimi was quiet at rest but showed a single fast firing unit on attempted contraction (gain = 200 mcV/div, time base = 10 ms/div). |
 | Media file 3: A 55-year-old man experienced pain and numbness in his right hand after prolonged laparotomy (Case study 2). Electrodiagnostic testing 3 days after the injury revealed the following: (Left) Right distal ulnar motor response is of lower amplitude than on day 1, approximately 50% of baseline (gain = 2 mV/div, time base = 5 milliseconds [ms]/div) with persistent conduction block across the elbow. (Right) Right ulnar sensory response is still normal (gain = 20 mcV/div, time base =2 ms/div). |
 | Media file 4: A 55-year-old man experienced pain and numbness in his right hand after prolonged laparotomy (Case study 2). Electrodiagnostic testing 6 days after the injury revealed the following: (Left) Right distal ulnar motor response is less than 10% of baseline (gain = 2 mV/div, time base = 5 milliseconds [ms]/div) with persistent conduction block across the elbow. (Right) Right ulnar sensory response amplitude still is relatively preserved at 50% of baseline (gain = 20 mcV/div, time base = 1 ms/div). |
 | Media file 5: A 55-year-old man experienced pain and numbness in his right hand after prolonged laparotomy (Case study 2). Electrodiagnostic testing 10 days after the injury revealed the following: Right ulnar motor (middle) and sensory (right) responses are absent. Needle electromyography (EMG) of first dorsal interosseus shows sparse denervation potentials with 1 fast firing unit on attempted volitional activity. |
 | Media file 6: A 64-year-old man sustained multiple neurovascular injuries affecting the left arm in a motor vehicle accident (Case study 3). Although he had considerable improvement in muscle strength in the 18 months after surgery, he had residual left biceps weakness and underwent reoperation. Intraoperative nerve action potentials recorded from the lateral cord (point R) with successive stimulation (at points 1, 2, 3, 4, and 5) along the course of the musculocutaneous nerve (gain = 100 mcV/div, time base = 0.5 milliseconds [ms]/div). Normal responses are recorded from stimulation at points 1 and 2. A slight increase in latency and drop in amplitude are noted on stimulation at point 3 close to the nerve injury. Stimulation at points 4 and 5 (distal to the injury) fail to evoke a recordable response. |
 | Media file 7: A 25-year-old man had a "flail" right arm after injury in a motorcycle accident (Case study 4). Left panel: Somatosensory evoked potentials (SEPs) recorded at the scalp from stimulation of the (healthy) middle trunk (gain = 0.2 mcV/div, time base = 10 milliseconds [ms]/div). Middle panel: SEPs recorded at the scalp from stimulation of the lower trunk—no reproducible responses present (gain = 0.2 mcV/div, time base = 10 ms/div). Right panel: "Super normal" nerve action potentials recorded at the lower trunk from stimulation of the medial cord (time base = 1.5 ms/div, gain = 20 mcV/div). |
More on Traumatic Peripheral Nerve Lesions |
| Overview: Traumatic Peripheral Nerve Lesions |
| Differential Diagnoses & Workup: Traumatic Peripheral Nerve Lesions |
| Treatment & Medication: Traumatic Peripheral Nerve Lesions |
| Follow-up: Traumatic Peripheral Nerve Lesions |
 Multimedia: Traumatic Peripheral Nerve Lesions |
| References |
| « Previous Page |
References
Brown WF, Veitch J. AAEM minimonograph #42: intraoperative monitoring of peripheral and cranial nerves. Muscle Nerve. Apr 1994;17(4):371-7. [Medline].
Byrne P, Hilinski J, Hilger P. Facial Nerve Repair. eMedicine Journal [serial online]. 2003. Available at: http://www.emedicine.com/ent/topic408.htm. [Full Text].
Chaput C, Probe R. Brachial Plexus Injuries, Traumatic. eMedicine Journal [serial online]. 2003. Available at: http://www.emedicine.com/orthoped/topic26.htm. [Full Text].
Chaudhry V, Cornblath DR. Wallerian degeneration in human nerves: serial electrophysiological studies. Muscle Nerve. Jun 1992;15(6):687-93. [Medline].
Kline DG, Hudson AR. Nerve Injuries: Operative Results for Major Nerve Injuries. Philadelphia, Pa: WB;1995.
Kliot M, Slimp J. Techniques for assessment of peripheral nerve function at surgery. In: Loftus CM, Traynelis VC, eds. Intraoperative Monitoring Techniques in Neurosurgery. New York: McGraw-Hill Inc;. 1994:275-85.
Landi A, Copeland SA, Parry CB, Jones SJ. The role of somatosensory evoked potentials and nerve conduction studies in the surgical management of brachial plexus injuries. J Bone Joint Surg [Br]. Nov 1980;62-B(4):492-6. [Medline].
Stewart JD. Focal Peripheral Neuropathies. New York: Raven Press;1993.
Tiel RL, Happel LT Jr, Kline DG. Nerve action potential recording method and equipment. Neurosurgery. Jul 1996;39(1):103-8; discussion 108-9. [Medline].
Wilbourn AJ. Assessment of the brachial plexus and the phrenic nerve. In: Johnson EW, Pease WS, eds. Practical Electromyography. Baltimore: Williams & Wilkins;1997:273-310.
Further Reading
Keywords
peripheral nerve injuries, complete nerve injury, incomplete nerve injury, segmental demyelination, neurapraxia, axonal injury, wallerian degeneration, axonal regeneration, focal remyelination, myelin sheath, evaluation of peripheral nerve injury, management of peripheral nerve injury, treatment of peripheral nerve injury
