| 제목 |
A CASE OF TRUE NEUROGENIC THORACIC OULET SYNDROME ACCOMPANIED BY AN ELONGATED C7 TRANSVERSE PROCESS |
| 소속 |
Korea University College of Medicine, Department of Physical Medicine & Rehabilitation1, Korea University College of Medicine, Department of Radiology2 |
| 저자 |
Hong Beom Park1*, Ki Hoon Kim1, Baek Hyun Kim1, Dong Hwee Kim1† |
OBJECTIVE AND BACKGROUND
True neurogenic thoracic outlet syndrome (TOS) is an unusual disease and hard to diagnose. Enlarged C7 transverse process is one of leading causes of TOS. We present a case of true neurogenic TOS correlated with enlarged C7 transverse process which was diagnosed by radiologic studies including magnetic resonance images (MRI) and computed tomography (CT).
CASE PRESENTATION
A 61-year-old man complained of progressive tingling sensation on the right medial forearm, and 4th and 5th fingers with shoulder pain for 4 years. On physical examination, sensation to touch was decreased in the right medial forearm and 4th and 5th finger. Muscle strength (Medical Research Council grade) of the right upper extremity demonstrated that abductor pollicis brevis (APB), abductor digiti minimi (ADM) and first dorsal interosseous (FDI) muscles were grade 3, but elbow flexor, wrist and finger extensor, grade 5. Compound muscle action potential (CMAP) of the right median nerve was decreased. Sensory nerve action potential (SNAP) of the right medial antebrachial cutaneous nerve was not evoked, and SNAPs of the right ulnar sensory nerve, dorsal ulnar cutaneous nerve, and median sensory nerve with third digit were decreased. But the right median sensory response with the first digit recording was normal. On needle electromyographic examination, abnormal spontaneous activities and/or large amplitude and long duration motor unit action potentials with reduced recruitment patterns were demonstrated the median and ulnar-innervated muscles originated from medial cord of the right brachial plexus. MRI of the right brachial plexus showed that the distal portion of lower trunk was compressed between subclavian artery and tip of transverse process (FIGURE A). CT demonstrated that enlarged and downward C7 transverse process and subclavian artery narrows outlet of lower trunk (FIGURE B). Plain X-ray of cervical spine showed bilateral elongated C7 transverse process, especially more elongated and downward transverse process on the right side. He refused surgical treatment. Conservative treatment including steroid therapy for 2 months, symptoms were relieved.
CONCLUSION
The enlarged, downward transverse process is a rare cause of true neurogenic TOS and should be considered in the differential diagnosis in a patient with a suspected TOS.
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MRI of the right brachial plexus showed compression of the distal portion of lower trunk between subclavian artery and C7 transverse process tip: thin arrow, subclavian artery; thick arrow, lower trunk; asterisk, tip of elongated C7 transverse process.
CT showed that the lower trunk of right brachial plexus was compressed between the subclavian artery and the tip of C7 transverse process (T) (a) as compared to the left side (b): A, subclavian artery; T, tip of elongated transverse process.
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