VISUAL VIGNETTE
Magnetic Resonance Imaging of a Fibrous Band Causing True Neurogenic Thoracic Outlet Syndrome Mustafa Turgut Yıldızgo¨ren, MD, Timur Ekiz, MD, Murat Kara, MD, Mehmet Yo¨ru¨bulut, MD, and Levent O¨zc¸akar, MD From the Department of Physical Medicine and Rehabilitation, Ankara Occupational Diseases Hospital (MTY); Department of Physical Medicine and Rehabilitation, Ankara Physical Medicine and Rehabilitation Training and Research Hospital (TE, MK); Department of Radiology, Primer Magnetic Resonance Imaging Center (MY); and Department of Physical Medicine and Rehabilitation, Hacettepe University Medical School (LO¨), Ankara, Turkey. Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article. 0894-9115/14/9308-0732 American Journal of Physical Medicine & Rehabilitation Copyright * 2014 by Lippincott Williams & Wilkins DOI: 10.1097/PHM.0000000000000090
A
17-yr-old girl was seen because of tingling, numbness, and weakness in her right upper limb (worse with head rotations) for the last 1 yr. The medical history was otherwise noncontributory. On physical examination, she had hypothenar atrophy on the right side. Motor examination was consistent with weakness of the right abductor digiti minimi muscle (4/5). Sensory examination revealed paresthesia at the right C8YT1 dermatome. Results of provocative tests for vascular compression were negative. Nerve conduction studies showed decreased median and ulnar nerve motor amplitudes and decreased sensory nerve conduction velocities of the right ulnar and medial antebrachial cutaneous nerves. Needle electromyography (abductor pollicis brevis, abductor digiti minimi, extensor indicis proprius muscles) yielded positive sharp waves and fibrillation potentials as spontaneous activity. Motor unit action potential analysis revealed decreased recruitment, increased amplitude/ duration, and polyphasia. Together with the normal electromyographic findings of C8YT1 paravertebral muscles, the patient was diagnosed with subacute, partial neuropathy of the lower-middle trunks of the brachial plexus. Results of cervical radiographs were normal. Magnetic resonance imaging demonstrated an aberrant fibrous band compressing the middle-lower trunks of the right brachial plexus (Fig. 1). Overall, the patient was diagnosed with true neurogenic
All correspondence and requests for reprints should be addressed to Mustafa Turgut YNldNzgo¨ren, MD, AtlNlar street No: 45, Kec¸io¨ren/Ankara 06280 Turkey.
732
FIGURE 1 Magnetic resonance neurography (A, B) showing pathologic thickening with increased signal intensity (neuritis-plexopathy) in the middle-lower trunks of the right brachial plexus. The fibrotic band (white arrow) is observed without a signal at the level of scalene muscles (B). On axial view (C), a longer transverse process of C7 (white arrowhead) is seen on the right side. Magnetic resonance angiography demonstrates normal arterial structures (D).
thoracic outlet syndrome (nTOS), and she was referred to thoracic surgery. She underwent surgical excision of the fibrous band, and her findings were significantly improved thereafter. Thoracic outlet syndrome is the constellation of findings as regards compression of the neurovascular structures in the cervicoaxillary region.1 Accordingly, it is usually classified as vascular, disputed nTOS, and true nTOS, the last one being very rare (1/1,000,000).2 True nTOS actually refers to the scenario in which the relevant symptoms are accompanied by overt neurologic findings (i.e., muscle weakness/atrophy) and distinct electrodiagnostic abnormalities, which do not exist in disputed nTOS.3 On the other hand, the spectrum of underlying causative factors (congenital or acquired) may be quite wide, and although the diagnosis is clinical, especially in patients who plan to undergo surgery, prompt imaging might be paramount. Likewise, in this report, the authors tried to underscore the role of magnetic resonance imaging for demonstration of the fibrous bands that are actually quite challenging.4 Although Roos has described several types of those congenital bands,4 the most common form is the Am. J. Phys. Med. Rehabil. & Vol. 93, No. 8, August 2014
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
one arising from a cervical rib and inserting onto the first rib.2,4 REFERENCES 1. O¨zc¸akar L, Inanici F, Kaymak B, et al: Quantification of the weakness and fatigue in thoracic outlet syndrome with isokinetic measurements. Br J Sports Med 2005;39:178Y81
www.ajpmr.com
2. Ferrante MA: The thoracic outlet syndromes. Muscle Nerve 2012;45:780Y95 3. Tsao BE, Ferrante MA, Wilbourn AJ, et al: The electrodiagnostic features of true neurogenic thoracic outlet syndrome. Muscle Nerve. 2013 doi: 10.1002/mus.24066 [Epub ahead of print] 4. Brantigan CO, Roos DB: Etiology of neurogenic thoracic outlet syndrome. Hand Clin 2004;20:17Y22
Visual Vignette Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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Magnetic Resonance Imaging of a Fibrous Band Causing True Neurogenic Thoracic Outlet Syndrome Mustafa Turgut Yıldızgo¨ren, MD, Timur Ekiz, MD, Murat Kara, MD, Mehmet Yo¨ru¨bulut, MD, and Levent O¨zc¸akar, MD From the Department of Physical Medicine and Rehabilitation, Ankara Occupational Diseases Hospital (MTY); Department of Physical Medicine and Rehabilitation, Ankara Physical Medicine and Rehabilitation Training and Research Hospital (TE, MK); Department of Radiology, Primer Magnetic Resonance Imaging Center (MY); and Department of Physical Medicine and Rehabilitation, Hacettepe University Medical School (LO¨), Ankara, Turkey. Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article. 0894-9115/14/9308-0732 American Journal of Physical Medicine & Rehabilitation Copyright * 2014 by Lippincott Williams & Wilkins DOI: 10.1097/PHM.0000000000000090
A
17-yr-old girl was seen because of tingling, numbness, and weakness in her right upper limb (worse with head rotations) for the last 1 yr. The medical history was otherwise noncontributory. On physical examination, she had hypothenar atrophy on the right side. Motor examination was consistent with weakness of the right abductor digiti minimi muscle (4/5). Sensory examination revealed paresthesia at the right C8YT1 dermatome. Results of provocative tests for vascular compression were negative. Nerve conduction studies showed decreased median and ulnar nerve motor amplitudes and decreased sensory nerve conduction velocities of the right ulnar and medial antebrachial cutaneous nerves. Needle electromyography (abductor pollicis brevis, abductor digiti minimi, extensor indicis proprius muscles) yielded positive sharp waves and fibrillation potentials as spontaneous activity. Motor unit action potential analysis revealed decreased recruitment, increased amplitude/ duration, and polyphasia. Together with the normal electromyographic findings of C8YT1 paravertebral muscles, the patient was diagnosed with subacute, partial neuropathy of the lower-middle trunks of the brachial plexus. Results of cervical radiographs were normal. Magnetic resonance imaging demonstrated an aberrant fibrous band compressing the middle-lower trunks of the right brachial plexus (Fig. 1). Overall, the patient was diagnosed with true neurogenic
All correspondence and requests for reprints should be addressed to Mustafa Turgut YNldNzgo¨ren, MD, AtlNlar street No: 45, Kec¸io¨ren/Ankara 06280 Turkey.
732
FIGURE 1 Magnetic resonance neurography (A, B) showing pathologic thickening with increased signal intensity (neuritis-plexopathy) in the middle-lower trunks of the right brachial plexus. The fibrotic band (white arrow) is observed without a signal at the level of scalene muscles (B). On axial view (C), a longer transverse process of C7 (white arrowhead) is seen on the right side. Magnetic resonance angiography demonstrates normal arterial structures (D).
thoracic outlet syndrome (nTOS), and she was referred to thoracic surgery. She underwent surgical excision of the fibrous band, and her findings were significantly improved thereafter. Thoracic outlet syndrome is the constellation of findings as regards compression of the neurovascular structures in the cervicoaxillary region.1 Accordingly, it is usually classified as vascular, disputed nTOS, and true nTOS, the last one being very rare (1/1,000,000).2 True nTOS actually refers to the scenario in which the relevant symptoms are accompanied by overt neurologic findings (i.e., muscle weakness/atrophy) and distinct electrodiagnostic abnormalities, which do not exist in disputed nTOS.3 On the other hand, the spectrum of underlying causative factors (congenital or acquired) may be quite wide, and although the diagnosis is clinical, especially in patients who plan to undergo surgery, prompt imaging might be paramount. Likewise, in this report, the authors tried to underscore the role of magnetic resonance imaging for demonstration of the fibrous bands that are actually quite challenging.4 Although Roos has described several types of those congenital bands,4 the most common form is the Am. J. Phys. Med. Rehabil. & Vol. 93, No. 8, August 2014
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
one arising from a cervical rib and inserting onto the first rib.2,4 REFERENCES 1. O¨zc¸akar L, Inanici F, Kaymak B, et al: Quantification of the weakness and fatigue in thoracic outlet syndrome with isokinetic measurements. Br J Sports Med 2005;39:178Y81
www.ajpmr.com
2. Ferrante MA: The thoracic outlet syndromes. Muscle Nerve 2012;45:780Y95 3. Tsao BE, Ferrante MA, Wilbourn AJ, et al: The electrodiagnostic features of true neurogenic thoracic outlet syndrome. Muscle Nerve. 2013 doi: 10.1002/mus.24066 [Epub ahead of print] 4. Brantigan CO, Roos DB: Etiology of neurogenic thoracic outlet syndrome. Hand Clin 2004;20:17Y22
Visual Vignette Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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