Accepted Manuscript Atypical thoracic outlet syndrome and reverse flow thromboembolism Robert D. Bains, FRCS(Plast) Jennica Platt, MD Daune MacGregor, MD, FRCP(C) Gregory H. Borschel, MD, FACS, FAAP PII:
S0887-8994(14)00264-1
DOI:
10.1016/j.pediatrneurol.2014.04.022
Reference:
PNU 8347
To appear in:
Pediatric Neurology
Received Date: 26 February 2014 Revised Date:
17 April 2014
Accepted Date: 20 April 2014
Please cite this article as: Bains RD, Platt J, MacGregor D, Borschel GH, Atypical thoracic outlet syndrome and reverse flow thromboembolism, Pediatric Neurology (2014), doi: 10.1016/ j.pediatrneurol.2014.04.022. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Atypical thoracic outlet syndrome and reverse flow thromboembolism Robert D Bains, FRCS(Plast)1,, Jennica Platt1, MD, Daune MacGregor, MD, FRCP(C), Gregory
RI PT
H. Borschel1, MD, FACS, FAAP Divisions of Plastic and Reconstructive Surgery1 and Neurology2 Hospital for Sick Children,
This is to certify that:
M AN U
The article has not been presented at a meeting.
SC
University of Toronto, Toronto, Ontario, Canada.
The authors did not receive any financial support from any public or private sources. The authors have no financial or proprietary interest in a product, method, or material
Corresponding author
TE D
described herein.
Gregory H. Borschel, MD, FACS, FAAP
555 University Avenue
M5G1X8 Canada
AC C
Toronto, ON
EP
The Hospital for Sick Children
Tel: +1 (416) 8137654 ext 228196 Fax: +1 (416) 813 8569
Email: [email protected]
Manuscript word count = 2660
ACCEPTED MANUSCRIPT
Abstract BACKGROUND. Thoracic outlet syndrome is rare in children but may have serious consequences.
RI PT
Compression of the neurovascular structures at the thoracic outlet by anomalous soft tissues or cervical ribs may cause neurological deficits in the upper limb as well as venous or arterial insufficiency.
PATIENTS. The symptoms and signs of this pathology are well documented but we describe two cases in
diagnosis resulted in cerebrovascular catastrophe.
SC
which the presentations were atypical. We review similar, previously published cases where delay in
M AN U
RESULTS. Two patients presented with relatively non-specific central nervous system symptoms and were found to have thoracic outlet compression. Both were treated by surgical decompression of the thoracic outlet and the symptoms completely resolved with no long lasting neurological consequences. CONCLUSIONS. We highlight the importance of these rare cases due to the risk of stroke and discuss
TE D
the theory behind the pathological process.
AC C
EP
Key words. Thoracic outlet syndrome, thromboembolism, stroke, migraine
ACCEPTED MANUSCRIPT
Introduction Thoracic outlet syndrome (TOS) in children is a rare but important condition. TOS may present
RI PT
with obstruction or compression of the structures passing through the thoracic outlet region. There are three sites of potential compression of the subclavian artery, vein or the brachial plexus in the thoracic outlet region: the interscalene, costoclavicular or subpectoral minor space 1. TOS can manifest with either neurological or vascular symptomatology usually affecting the upper
SC
limbs, and thus can be classified into neurogenic, venous or arterial subtypes based on clinical
M AN U
symptoms, findings on exam and diagnostic imaging. Compression of the subclavian vessels or brachial plexus at the thoracic outlet region is well documented, and the etiology can include abnormal soft tissue, abnormal first ribs, or cervical ribs. Often a combination of these factors is noted at surgical exploration. Venous TOS is uncommon in adults, comprising < 10% of cases; arterial TOS is rare, comprising < 1% of cases 2, and neurogenic TOS is the most common,
TE D
comprising over 90% of cases. In contrast, vascular TOS subtypes are more common in the pediatric population, comprising up to 74% in pediatric case series, however arterial TOS remains least common subtype
3,4
. Neurogenic symptoms with or without vascular involvement
EP
are only seen in around 50% of pediatric cases5. Venous TOS often presents with arm swelling
AC C
with or without subclavian vein thrombosis and arterial TOS is characterized by symptoms of acute or chronic limb ischemia; chronic compression of the vessel can result in damage to the artery with stenosis, post stenotic dilatation or post-stenotic aneurysm. Neurogenic TOS is the most common subtype in adults, where brachial plexus nerve roots are compressed between the scalene muscles and their insertion on the first rib causing complaints of pain, weakness, paresthesias and a cool extremity. Symptoms are usually exacerbated with the arms abducted and
ACCEPTED MANUSCRIPT
with repetitive motions
2-4
. The symptoms of vascular and neurologic compression can coexist
and a spectrum of symptoms and presenting features has been reported 6.
RI PT
Diagnosing thoracic outlet syndrome can be difficult due to the variation in presenting symptoms and overlap with other differential diagnoses. Compounding these factors is the fact that the clinical signs and tests can be unreliable in confirming the diagnosis 1. For example, Adson’s sign (loss of the radial pulse in the arm on the involved side with head rotation and the neck in
SC
extension after deep inspiration) is no longer considered to be of value1. X-ray, MRI and
M AN U
angiography can all add valuable clues regarding abnormal anatomy and resultant vascular compression or secondary pathology. We present two cases to highlight cerebrovascular insufficiency as an uncommon presentation of TOS in adolescents, where permanent and devastating central neurologic sequelae were potentially avoided through surgical treatment. This is an extremely rare presentation associated with cervical rib and TOS that has been reported in
TE D
only a few case reports previously7-9. We present a brief review of the literature and suggest implications for practice regarding the management of children and adolescents that develop
Case 1
AC C
Case reports
EP
TOS from a mechanical obstruction at the thoracic outlet.
A twelve-year-old boy was referred to our department with a history of chest pain and bilateral cyanosis of the hands on exertion. This particularly occurred after hockey games and at rest with the arms abducted and externally rotated. Examination did not reveal any motor or sensory deficits in the upper limbs but Roos test was positive (i.e., on abduction of the shoulders he had paresthesias radiating down both limbs).
ACCEPTED MANUSCRIPT
Magnetic resonance imaging showed small bilateral ribs, which were either hypoplastic first ribs or cervical ribs. Dynamic ultrasound showed significant compression of the upper limb vessels bilaterally. The right subclavian artery narrowed from 8 to 3 mm on shoulder abduction and the
RI PT
subclavian vein narrowed from 4 to 1 mm (Figures 1 and 2). On the left side the subclavian artery narrowed from 8 to 1.5 mm and the vein narrowed from 11 to 0.5mm. Surgery for
SC
decompression of the thoracic outlet was then planned.
In the interim the patient experienced two episodes of loss of consciousness and following these
M AN U
was noted to have slurred speech, vertigo and lightheadedness. At this time his symptoms progressed and he complained of headaches, vertigo, lightheadedness, slurred speech and partial visual loss whenever he elevated his arms or carried out any physical exercise.
On physical examination, there was restriction in external rotation and movement of the
TE D
shoulders bilaterally. In repose, there was reddish – blue discoloration of the hands and feet. There was mild bilateral pes planus and a hammertoe of the second toe of the right foot. He was not dysmorphic. Formal neurological examination showed the cranial nerves to be normal. There
EP
was a slight tremulousness with the right arm held in extension at the elbow. There was no drift
AC C
of either outstretched arm. Rapid finger tapping was normal. There was an awkward heel and toe – walking movement. Balance testing with stork standing showed considerable swaying to either side – right sightly more than left. The deep tendon reflexes were graded at 2+/4 bilaterally with down-going plantar responses. Sensory examination was normal. Cerebellar testing with finger – nose – finger assessment was normal but rapid alternating movements were mildly poor quality for age. Walking gait was normal. There was a very abnormal tandem gait with a tendency to sway more for the right.
ACCEPTED MANUSCRIPT
Conventional angiography (Figure 1) revealed the previously noted subclavian compression but no abnormality or compression of either vertebral artery was seen. Subsequent magnetic resonance imaging of the brain revealed a small linear focus of restricted diffusion in the superior
RI PT
left cerebellum. The area was hypointense on T1 and hyperintense on T2WI, consistent with acute
SC
ischemic changes.
At surgical exploration of the left thoracic outlet dense adhesions were noted between anterior
M AN U
and posterior scalene muscles. These were divided and the first rib was excised. The vertebral artery was explored and no abnormality or compression of the artery was seen. Intraoperative Doppler revealed good flow in the vessel. The left thoracic outlet was decompressed first and the same procedure was carried out on the right side six months later.
TE D
Following surgery the patient recovered uneventfully and all symptoms in the limbs completely resolved. The posterior fossa symptoms were alleviated completely following the procedure on the left side. Clinical neurological assessment six months after the second surgical procedure
EP
showed improved tandem gait and mild appendicular dyscoordination. The only symptoms at that time consisted of subjective numbness of the lateral aspect of the left-hand and "shakiness"
AC C
when drinking from a glass. Follow-up at one year indicated no neurological symptomatology however the child complained of decreased heat sensitivity in both hands. Formal neurological examination was unremarkable Case 2 A 15-year-old girl was referred for symptoms of worsening numbness and weakness in the left hand, accompanied by occasional radicular pain originating from the left side of the neck.
ACCEPTED MANUSCRIPT
Symptoms were exacerbated with neck movement and left arm abduction. She also had symptoms of headache and visual disturbance occurring with increasing frequency of up to six times per month during the preceding months. The majority of the visual symptoms consisted of
RI PT
fleeting black spots but one episode resulted in loss of the lower visual field in the left eye and this persisted for four weeks. These symptoms had been attributed to migraine and were frequently associated with syncopal episodes. Some of the syncopal episodes occurred after a
SC
period of headache and visual disturbance but at other times they occurred without warning and were associated with confusion afterwards. This had resulted in the patient missing three months
M AN U
of school in the year prior to referral. Examination revealed left-sided hypoesthesia in the median, ulnar and radial nerve distribution distal to the elbow with a positive Tinel sign between the anterior and middle scalene and diminished grip strength. Roos test could not be performed due to severe pain on abduction of the left shoulder. Central nervous examination was normal.
TE D
Because of the syncopal episodes and headaches she underwent magnetic resonance scan of the brain, which was nondiagnostic.
At surgery, a sharp band on the posterior surface of the anterior scalene was divided, and a
EP
cervical rib was resected. The patient noted complete resolution of left-sided numbness,
AC C
paresthesia and motor impairment by the second post-operative month, with full shoulder range of motion. Additionally, the headaches, visual disturbance and syncope resolved after surgical release of the obstruction to the thoracic outlet.
Discussion
We present two adolescents with TOS presenting with upper limb and central neurological symptoms. In both cases the neurological symptoms in isolation could have been attributed to a
ACCEPTED MANUSCRIPT
range of other causes such as migraine. In both cases, however, all of these symptoms resolved following decompression of the thoracic outlet. It is our belief therefore that the central nervous symptoms, as well as the upper limb symptoms arose in association with thoracic outlet
RI PT
compression and resultant transient ischemic episodes from thromboembolism. Our first case presented with cerebellar symptoms and subsequent MRI demonstrated evidence of ischemia in the central cerebellar region. The majority of the symptoms in the second patient could have
SC
been explained by migraine but her syncopal episodes were not typical and she experienced an episode of visual field loss, which only resolved after four weeks. We feel therefore that this is
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more likely to represent an embolic episode. Unfortunately she did not present during this time for imaging and her MRI brain prior to this was normal. In both cases there was dramatic resolution of symptoms following thoracic outlet decompression and in the second case all anti migraine medication was stopped.
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Thoracic outlet syndrome usually occurs in adults, and neurologic symptoms predominate in this population. These may be categorized into typical specific or non-specific subtypes. The latter exhibits no focal neurological findings and pain may be the main presenting feature9. Usually
EP
neurological consequences of thoracic outlet syndrome are concerned with direct peripheral
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nerve compression in the interscalene triangle. The lower roots of the brachial plexus are affected producing weakness of the intrinsic muscles of the hand and pain and paresthesia affecting the ulnar side of the hand and forearm. It is possible also for the patient with thoracic outlet syndrome to exhibit central neurological deficits secondary to vascular compression and subsequent thromboembolism. Cerebrovascular insufficiency and stroke has been reported in association with TOS in adolescents and young adults8,9 with devastating results. The majority of these cases have
ACCEPTED MANUSCRIPT
involved the anterior (carotid) circulation but the vertebrobasilar system can also be affected12. While presentation with central neurological symptoms is extremely rare, it is one with which the surgeon, neurologist and pediatrician should be familiar, given the difficulty with diagnosis
RI PT
and profound implications if left unrecognized.
Several authors have described the condition in younger age groups and there is increasing
SC
evidence that adolescent thoracic outlet syndrome not only exists as an entity but may differ from the adult presentation. Some authors have suggested that bony abnormalities may be more
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of a feature in the adolescent group and this may result in more frequent vascular compromise in younger age groups. Several studies have shown proportionately more vascular compression in the younger age groups. Venous and neurogenic thoracic outlet symptoms are also common in adolescent groups but arterial compromise has been described in up to 38% of cases 3.
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Neurological TOS can result in chronic loss of neurological function and venous TOS can result in venous insufficiency secondary to damage from thrombus. It is the arterial group however that may experience the most devastating consequences of compression of the thoracic outlet with
EP
limb ischemia and thromboembolism resulting from chronic arterial injury. Repeated compression of the subclavian artery causes intimal damage, which can result in atheroma
AC C
formation and scarring. With progression of the condition stenosis of the artery can occur and in the most severe cases post stenotic aneurysm and distal vascular occlusion can result. This may be ameliorated to some extent by dilatation of collateral vessels but despite collateralization, ischemic sequalae are commonly found in the presence of such significant vessel injury. Many authors describe chronic or acute upper limb ischemia in the presence of cervical rib and secondary subclavian artery injury. Cases have been described where the acute arm ischemia following thomboembolism is the presenting feature of the thoracic outlet syndrome4.
ACCEPTED MANUSCRIPT
A rare but potentially more devastating consequence of subclavian damage is that of central nervous ischemia secondary to thromboembolism. The site of damage to the subclavian vessel is distal to the origin of the carotid and the vertebral artery on the right and distal to the vertebral
RI PT
origin on the left. The left carotid arises directly from the aortic arch and is therefore even more remote. Despite this anatomical arrangement thromboembolism from a damaged subclavian artery to the brain is possible. There are cases described in the literature of right-sided middle
SC
cerebral infarction associated with cervical rib and aneurysmal/occluded subclavian artery9,13,14. Prior et al described five cases of thromboembolism where the thrombus travelled in a retrograde
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fashion, against the direction of arterial flow to result in stroke. In three of these cases the diagnosis was thoracic outlet syndrome secondary to cervical rib7. Interestingly, two of the cases did not exhibit occlusion or aneurysm of the subclavian artery. These authors also demonstrated reverse flow on Doppler ultrasound in a normal subject in the subclavian artery at different
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stages of systole. These findings may explain the potential for retrograde thromboembolism in cases of thoracic outlet syndrome. Gooneratne described a case of a 21 year old who suffered a pontine thromboembolic stroke in the context of right sided thoracic outlet syndrome. In this
EP
case retrograde thromboembolism was thought to have occurred and retrograde flow was demonstrated in the subclavian vessels. In this case the vascular damage was proven to be at an
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advanced stage with stenosis and post stenotic dilatation of the subclavian artery15. Many of the cases of stroke in the literature resulting from thoracic outlet syndrome occur from right sided compression of the subclavian artery and result in right middle cerebral, anterior circulation stroke
7-9
. The anatomy of the right subclavian tributaries would also allow for the
potential for posterior circulation stroke but perhaps the emboli preferentially flow into the larger carotid vessel. The vascular anatomy of the left subclavian artery differs in that the carotid artery
ACCEPTED MANUSCRIPT
originates directly from the aortic arch so a vertebrobasilar embolus is far more likely 8. It may be that case 3 from Prior’s series experienced this as the pathology was left sided and the symptoms consisted of vertigo and lightheadedness, which may be associated with
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vertebrobasilar ischemia 7.
Both of our cases experienced transient symptomatology consistent with posterior fossa ischemia
SC
and both improved following left sided thoracic outlet decompression. Neither case had radiologically evident vascular or central nervous damage, but it may be that the changes were
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still in their early stages. Some authors suggest that vascular damage may be underestimated in these cases11. Criado et al demonstrated that 24 of 27 patients with symptoms of chronic neurogenic TOS had subclavian artery stenosis, post-stenotic dilatation or both11. Symptoms of posterior fossa ischemia may be nonspecific in their early stages and may be attributed to other causes. Intermittent vertigo, lightheadedness and poor concentration are more commonly
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associated with diagnoses such as migraine, partial forms of epileptic seizures, sleep apnea, inner ear pathology, cardiac arrhythmias and depression. TOS is, however, an extremely important diagnosis to consider, as the results of stroke can be devastating. It is particularly important to
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recognize the potential association of these neurological symptoms in the setting of left sided
AC C
thoracic outlet syndrome.
The two patients in our report were fortunate in that their thoracic outlet syndrome was recognized early. Despite that fact that the condition had caused secondary neurological effects, no permanent injury ensued and they both responded well to decompression of the thoracic outlet.
SC
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References
Atasoy E. A hand surgeon's further experience with thoracic outlet compression syndrome. Journal of Hand Surgery - American Volume. 2010;35(9):1528-1538.
2.
Sanders RJ, Hammond SL, Rao NM. Diagnosis of thoracic outlet syndrome. Journal of Vascular Surgery. 2007;46:601 - 604.
3.
Chang K, Graf E, Davis K, Demos J, Roethle T, Freischlag JA. Spectrum of thoracic outlet syndrome presentation in adolescents. Archives of Surgery. 2011;146(12):13831387.
4.
Maru S, Dosluoglu H, Dryjski M, Cherr G, Curl GR, Harris LM. Thoracic outlet syndrome in children and young adults. European Journal of Vascular & Endovascular Surgery. 2009;38(5):560-564.
5.
Vu AT, Patel PA, Elhadi H, Schwentker AR, Yakuboff KP. Thoracic outlet syndrome in the pediatric population: case series. J Hand Surg Am. 2014 Mar;39(3):484-487.e2.
6.
Gruss JD. Thoracic outlet syndrome (TOS). International Angiology. 2009;28(3):167169.
7.
Prior AL, Wilson LA, Gosling RG, Yates AK, Ross Russell RW. Retrograde cerebral embolism. Lancet. Nov 17 1979;2(8151):1044-1047.
8.
Kataria R, Sharma A, Srivastava T, Bagaria H, Sharma A. Cervical rib, a rare cause of recurrent stroke in the young: Case Report. The neurologist. 2012;18:321-323.
9.
Lee TS, Hines GL. Cerebral embolic stroke and arm ischemia in a teenager with arterial thoracic outlet syndrome: a case report. Vascular and endovascular surgery. Jun-Jul 2007;41(3):254-257.
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EP
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1.
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Huang JH, Zager EL. Thoracic outlet syndrome. Neurosurgery. 2004 Oct;55(4):897-902; discussion 902-3.
11.
Criado E, Berguer R, Greenfield L. The spectrum of arterial compression at the thoracic outlet. Journal of Vascular Surgery. 2010;52(2):406-411.
12.
Yamaguchi R, Kohga H, Kurosaki M, et al. Acute basilar artery occlusion in a patient with left subclavian artery occlusion due to first rib anomaly: case report. Neurol Med Chir (Tokyo). 2008 Aug;48(8):355-8.
13.
al-Hassan HK, Abdul Sattar M, Eklof B. Embolic brain infarction: a rare complication of thoracic outlet syndrome. A report of two cases. J Cardiovasc Surg (Torino). 1988 MayJun;29(3):322-5.
14.
Davis JM, Golinger D. Cervical rib, subclavian artery aneurysm, axillary and cerebral emboli. Proc R Soc Med. 1966 Oct;59(10):1002-4
15.
Gooneratne IK, Gamage R, Gunarathne KS. Pearls & oy-sters: distal subclavian artery: a source of cerebral embolism. Neurology. 2009 Jul 14;73(2):e11-2.
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10.
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Figures
Figure 1: Left subclavian artery with arm neutral. Subclavian artery is of normal caliber
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SC
throughout.
Figure 2: Left subclavian artery with arm abducted. Stenosis can be seen as the artery crosses the
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first rib (arrow).
This is to certify that:
EP
The article has not been presented at a meeting.
The authors did not receive any financial support from any public or private sources.
AC C
The authors have no financial or proprietary interest in a product, method, or material described herein.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
S0887-8994(14)00264-1
DOI:
10.1016/j.pediatrneurol.2014.04.022
Reference:
PNU 8347
To appear in:
Pediatric Neurology
Received Date: 26 February 2014 Revised Date:
17 April 2014
Accepted Date: 20 April 2014
Please cite this article as: Bains RD, Platt J, MacGregor D, Borschel GH, Atypical thoracic outlet syndrome and reverse flow thromboembolism, Pediatric Neurology (2014), doi: 10.1016/ j.pediatrneurol.2014.04.022. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Atypical thoracic outlet syndrome and reverse flow thromboembolism Robert D Bains, FRCS(Plast)1,, Jennica Platt1, MD, Daune MacGregor, MD, FRCP(C), Gregory
RI PT
H. Borschel1, MD, FACS, FAAP Divisions of Plastic and Reconstructive Surgery1 and Neurology2 Hospital for Sick Children,
This is to certify that:
M AN U
The article has not been presented at a meeting.
SC
University of Toronto, Toronto, Ontario, Canada.
The authors did not receive any financial support from any public or private sources. The authors have no financial or proprietary interest in a product, method, or material
Corresponding author
TE D
described herein.
Gregory H. Borschel, MD, FACS, FAAP
555 University Avenue
M5G1X8 Canada
AC C
Toronto, ON
EP
The Hospital for Sick Children
Tel: +1 (416) 8137654 ext 228196 Fax: +1 (416) 813 8569
Email: [email protected]
Manuscript word count = 2660
ACCEPTED MANUSCRIPT
Abstract BACKGROUND. Thoracic outlet syndrome is rare in children but may have serious consequences.
RI PT
Compression of the neurovascular structures at the thoracic outlet by anomalous soft tissues or cervical ribs may cause neurological deficits in the upper limb as well as venous or arterial insufficiency.
PATIENTS. The symptoms and signs of this pathology are well documented but we describe two cases in
diagnosis resulted in cerebrovascular catastrophe.
SC
which the presentations were atypical. We review similar, previously published cases where delay in
M AN U
RESULTS. Two patients presented with relatively non-specific central nervous system symptoms and were found to have thoracic outlet compression. Both were treated by surgical decompression of the thoracic outlet and the symptoms completely resolved with no long lasting neurological consequences. CONCLUSIONS. We highlight the importance of these rare cases due to the risk of stroke and discuss
TE D
the theory behind the pathological process.
AC C
EP
Key words. Thoracic outlet syndrome, thromboembolism, stroke, migraine
ACCEPTED MANUSCRIPT
Introduction Thoracic outlet syndrome (TOS) in children is a rare but important condition. TOS may present
RI PT
with obstruction or compression of the structures passing through the thoracic outlet region. There are three sites of potential compression of the subclavian artery, vein or the brachial plexus in the thoracic outlet region: the interscalene, costoclavicular or subpectoral minor space 1. TOS can manifest with either neurological or vascular symptomatology usually affecting the upper
SC
limbs, and thus can be classified into neurogenic, venous or arterial subtypes based on clinical
M AN U
symptoms, findings on exam and diagnostic imaging. Compression of the subclavian vessels or brachial plexus at the thoracic outlet region is well documented, and the etiology can include abnormal soft tissue, abnormal first ribs, or cervical ribs. Often a combination of these factors is noted at surgical exploration. Venous TOS is uncommon in adults, comprising < 10% of cases; arterial TOS is rare, comprising < 1% of cases 2, and neurogenic TOS is the most common,
TE D
comprising over 90% of cases. In contrast, vascular TOS subtypes are more common in the pediatric population, comprising up to 74% in pediatric case series, however arterial TOS remains least common subtype
3,4
. Neurogenic symptoms with or without vascular involvement
EP
are only seen in around 50% of pediatric cases5. Venous TOS often presents with arm swelling
AC C
with or without subclavian vein thrombosis and arterial TOS is characterized by symptoms of acute or chronic limb ischemia; chronic compression of the vessel can result in damage to the artery with stenosis, post stenotic dilatation or post-stenotic aneurysm. Neurogenic TOS is the most common subtype in adults, where brachial plexus nerve roots are compressed between the scalene muscles and their insertion on the first rib causing complaints of pain, weakness, paresthesias and a cool extremity. Symptoms are usually exacerbated with the arms abducted and
ACCEPTED MANUSCRIPT
with repetitive motions
2-4
. The symptoms of vascular and neurologic compression can coexist
and a spectrum of symptoms and presenting features has been reported 6.
RI PT
Diagnosing thoracic outlet syndrome can be difficult due to the variation in presenting symptoms and overlap with other differential diagnoses. Compounding these factors is the fact that the clinical signs and tests can be unreliable in confirming the diagnosis 1. For example, Adson’s sign (loss of the radial pulse in the arm on the involved side with head rotation and the neck in
SC
extension after deep inspiration) is no longer considered to be of value1. X-ray, MRI and
M AN U
angiography can all add valuable clues regarding abnormal anatomy and resultant vascular compression or secondary pathology. We present two cases to highlight cerebrovascular insufficiency as an uncommon presentation of TOS in adolescents, where permanent and devastating central neurologic sequelae were potentially avoided through surgical treatment. This is an extremely rare presentation associated with cervical rib and TOS that has been reported in
TE D
only a few case reports previously7-9. We present a brief review of the literature and suggest implications for practice regarding the management of children and adolescents that develop
Case 1
AC C
Case reports
EP
TOS from a mechanical obstruction at the thoracic outlet.
A twelve-year-old boy was referred to our department with a history of chest pain and bilateral cyanosis of the hands on exertion. This particularly occurred after hockey games and at rest with the arms abducted and externally rotated. Examination did not reveal any motor or sensory deficits in the upper limbs but Roos test was positive (i.e., on abduction of the shoulders he had paresthesias radiating down both limbs).
ACCEPTED MANUSCRIPT
Magnetic resonance imaging showed small bilateral ribs, which were either hypoplastic first ribs or cervical ribs. Dynamic ultrasound showed significant compression of the upper limb vessels bilaterally. The right subclavian artery narrowed from 8 to 3 mm on shoulder abduction and the
RI PT
subclavian vein narrowed from 4 to 1 mm (Figures 1 and 2). On the left side the subclavian artery narrowed from 8 to 1.5 mm and the vein narrowed from 11 to 0.5mm. Surgery for
SC
decompression of the thoracic outlet was then planned.
In the interim the patient experienced two episodes of loss of consciousness and following these
M AN U
was noted to have slurred speech, vertigo and lightheadedness. At this time his symptoms progressed and he complained of headaches, vertigo, lightheadedness, slurred speech and partial visual loss whenever he elevated his arms or carried out any physical exercise.
On physical examination, there was restriction in external rotation and movement of the
TE D
shoulders bilaterally. In repose, there was reddish – blue discoloration of the hands and feet. There was mild bilateral pes planus and a hammertoe of the second toe of the right foot. He was not dysmorphic. Formal neurological examination showed the cranial nerves to be normal. There
EP
was a slight tremulousness with the right arm held in extension at the elbow. There was no drift
AC C
of either outstretched arm. Rapid finger tapping was normal. There was an awkward heel and toe – walking movement. Balance testing with stork standing showed considerable swaying to either side – right sightly more than left. The deep tendon reflexes were graded at 2+/4 bilaterally with down-going plantar responses. Sensory examination was normal. Cerebellar testing with finger – nose – finger assessment was normal but rapid alternating movements were mildly poor quality for age. Walking gait was normal. There was a very abnormal tandem gait with a tendency to sway more for the right.
ACCEPTED MANUSCRIPT
Conventional angiography (Figure 1) revealed the previously noted subclavian compression but no abnormality or compression of either vertebral artery was seen. Subsequent magnetic resonance imaging of the brain revealed a small linear focus of restricted diffusion in the superior
RI PT
left cerebellum. The area was hypointense on T1 and hyperintense on T2WI, consistent with acute
SC
ischemic changes.
At surgical exploration of the left thoracic outlet dense adhesions were noted between anterior
M AN U
and posterior scalene muscles. These were divided and the first rib was excised. The vertebral artery was explored and no abnormality or compression of the artery was seen. Intraoperative Doppler revealed good flow in the vessel. The left thoracic outlet was decompressed first and the same procedure was carried out on the right side six months later.
TE D
Following surgery the patient recovered uneventfully and all symptoms in the limbs completely resolved. The posterior fossa symptoms were alleviated completely following the procedure on the left side. Clinical neurological assessment six months after the second surgical procedure
EP
showed improved tandem gait and mild appendicular dyscoordination. The only symptoms at that time consisted of subjective numbness of the lateral aspect of the left-hand and "shakiness"
AC C
when drinking from a glass. Follow-up at one year indicated no neurological symptomatology however the child complained of decreased heat sensitivity in both hands. Formal neurological examination was unremarkable Case 2 A 15-year-old girl was referred for symptoms of worsening numbness and weakness in the left hand, accompanied by occasional radicular pain originating from the left side of the neck.
ACCEPTED MANUSCRIPT
Symptoms were exacerbated with neck movement and left arm abduction. She also had symptoms of headache and visual disturbance occurring with increasing frequency of up to six times per month during the preceding months. The majority of the visual symptoms consisted of
RI PT
fleeting black spots but one episode resulted in loss of the lower visual field in the left eye and this persisted for four weeks. These symptoms had been attributed to migraine and were frequently associated with syncopal episodes. Some of the syncopal episodes occurred after a
SC
period of headache and visual disturbance but at other times they occurred without warning and were associated with confusion afterwards. This had resulted in the patient missing three months
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of school in the year prior to referral. Examination revealed left-sided hypoesthesia in the median, ulnar and radial nerve distribution distal to the elbow with a positive Tinel sign between the anterior and middle scalene and diminished grip strength. Roos test could not be performed due to severe pain on abduction of the left shoulder. Central nervous examination was normal.
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Because of the syncopal episodes and headaches she underwent magnetic resonance scan of the brain, which was nondiagnostic.
At surgery, a sharp band on the posterior surface of the anterior scalene was divided, and a
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cervical rib was resected. The patient noted complete resolution of left-sided numbness,
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paresthesia and motor impairment by the second post-operative month, with full shoulder range of motion. Additionally, the headaches, visual disturbance and syncope resolved after surgical release of the obstruction to the thoracic outlet.
Discussion
We present two adolescents with TOS presenting with upper limb and central neurological symptoms. In both cases the neurological symptoms in isolation could have been attributed to a
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range of other causes such as migraine. In both cases, however, all of these symptoms resolved following decompression of the thoracic outlet. It is our belief therefore that the central nervous symptoms, as well as the upper limb symptoms arose in association with thoracic outlet
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compression and resultant transient ischemic episodes from thromboembolism. Our first case presented with cerebellar symptoms and subsequent MRI demonstrated evidence of ischemia in the central cerebellar region. The majority of the symptoms in the second patient could have
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been explained by migraine but her syncopal episodes were not typical and she experienced an episode of visual field loss, which only resolved after four weeks. We feel therefore that this is
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more likely to represent an embolic episode. Unfortunately she did not present during this time for imaging and her MRI brain prior to this was normal. In both cases there was dramatic resolution of symptoms following thoracic outlet decompression and in the second case all anti migraine medication was stopped.
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Thoracic outlet syndrome usually occurs in adults, and neurologic symptoms predominate in this population. These may be categorized into typical specific or non-specific subtypes. The latter exhibits no focal neurological findings and pain may be the main presenting feature9. Usually
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neurological consequences of thoracic outlet syndrome are concerned with direct peripheral
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nerve compression in the interscalene triangle. The lower roots of the brachial plexus are affected producing weakness of the intrinsic muscles of the hand and pain and paresthesia affecting the ulnar side of the hand and forearm. It is possible also for the patient with thoracic outlet syndrome to exhibit central neurological deficits secondary to vascular compression and subsequent thromboembolism. Cerebrovascular insufficiency and stroke has been reported in association with TOS in adolescents and young adults8,9 with devastating results. The majority of these cases have
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involved the anterior (carotid) circulation but the vertebrobasilar system can also be affected12. While presentation with central neurological symptoms is extremely rare, it is one with which the surgeon, neurologist and pediatrician should be familiar, given the difficulty with diagnosis
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and profound implications if left unrecognized.
Several authors have described the condition in younger age groups and there is increasing
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evidence that adolescent thoracic outlet syndrome not only exists as an entity but may differ from the adult presentation. Some authors have suggested that bony abnormalities may be more
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of a feature in the adolescent group and this may result in more frequent vascular compromise in younger age groups. Several studies have shown proportionately more vascular compression in the younger age groups. Venous and neurogenic thoracic outlet symptoms are also common in adolescent groups but arterial compromise has been described in up to 38% of cases 3.
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Neurological TOS can result in chronic loss of neurological function and venous TOS can result in venous insufficiency secondary to damage from thrombus. It is the arterial group however that may experience the most devastating consequences of compression of the thoracic outlet with
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limb ischemia and thromboembolism resulting from chronic arterial injury. Repeated compression of the subclavian artery causes intimal damage, which can result in atheroma
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formation and scarring. With progression of the condition stenosis of the artery can occur and in the most severe cases post stenotic aneurysm and distal vascular occlusion can result. This may be ameliorated to some extent by dilatation of collateral vessels but despite collateralization, ischemic sequalae are commonly found in the presence of such significant vessel injury. Many authors describe chronic or acute upper limb ischemia in the presence of cervical rib and secondary subclavian artery injury. Cases have been described where the acute arm ischemia following thomboembolism is the presenting feature of the thoracic outlet syndrome4.
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A rare but potentially more devastating consequence of subclavian damage is that of central nervous ischemia secondary to thromboembolism. The site of damage to the subclavian vessel is distal to the origin of the carotid and the vertebral artery on the right and distal to the vertebral
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origin on the left. The left carotid arises directly from the aortic arch and is therefore even more remote. Despite this anatomical arrangement thromboembolism from a damaged subclavian artery to the brain is possible. There are cases described in the literature of right-sided middle
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cerebral infarction associated with cervical rib and aneurysmal/occluded subclavian artery9,13,14. Prior et al described five cases of thromboembolism where the thrombus travelled in a retrograde
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fashion, against the direction of arterial flow to result in stroke. In three of these cases the diagnosis was thoracic outlet syndrome secondary to cervical rib7. Interestingly, two of the cases did not exhibit occlusion or aneurysm of the subclavian artery. These authors also demonstrated reverse flow on Doppler ultrasound in a normal subject in the subclavian artery at different
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stages of systole. These findings may explain the potential for retrograde thromboembolism in cases of thoracic outlet syndrome. Gooneratne described a case of a 21 year old who suffered a pontine thromboembolic stroke in the context of right sided thoracic outlet syndrome. In this
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case retrograde thromboembolism was thought to have occurred and retrograde flow was demonstrated in the subclavian vessels. In this case the vascular damage was proven to be at an
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advanced stage with stenosis and post stenotic dilatation of the subclavian artery15. Many of the cases of stroke in the literature resulting from thoracic outlet syndrome occur from right sided compression of the subclavian artery and result in right middle cerebral, anterior circulation stroke
7-9
. The anatomy of the right subclavian tributaries would also allow for the
potential for posterior circulation stroke but perhaps the emboli preferentially flow into the larger carotid vessel. The vascular anatomy of the left subclavian artery differs in that the carotid artery
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originates directly from the aortic arch so a vertebrobasilar embolus is far more likely 8. It may be that case 3 from Prior’s series experienced this as the pathology was left sided and the symptoms consisted of vertigo and lightheadedness, which may be associated with
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vertebrobasilar ischemia 7.
Both of our cases experienced transient symptomatology consistent with posterior fossa ischemia
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and both improved following left sided thoracic outlet decompression. Neither case had radiologically evident vascular or central nervous damage, but it may be that the changes were
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still in their early stages. Some authors suggest that vascular damage may be underestimated in these cases11. Criado et al demonstrated that 24 of 27 patients with symptoms of chronic neurogenic TOS had subclavian artery stenosis, post-stenotic dilatation or both11. Symptoms of posterior fossa ischemia may be nonspecific in their early stages and may be attributed to other causes. Intermittent vertigo, lightheadedness and poor concentration are more commonly
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associated with diagnoses such as migraine, partial forms of epileptic seizures, sleep apnea, inner ear pathology, cardiac arrhythmias and depression. TOS is, however, an extremely important diagnosis to consider, as the results of stroke can be devastating. It is particularly important to
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recognize the potential association of these neurological symptoms in the setting of left sided
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thoracic outlet syndrome.
The two patients in our report were fortunate in that their thoracic outlet syndrome was recognized early. Despite that fact that the condition had caused secondary neurological effects, no permanent injury ensued and they both responded well to decompression of the thoracic outlet.
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References
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Figures
Figure 1: Left subclavian artery with arm neutral. Subclavian artery is of normal caliber
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throughout.
Figure 2: Left subclavian artery with arm abducted. Stenosis can be seen as the artery crosses the
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first rib (arrow).
This is to certify that:
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The article has not been presented at a meeting.
The authors did not receive any financial support from any public or private sources.
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The authors have no financial or proprietary interest in a product, method, or material described herein.
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