Original Article
Brachial Plexus Injury: Diagnosis of Nerve Root Avulsion
Using Multislice CT Myelography
Ahmed Fathy Abdel Ghany1, Noha Mohamed Osman Rabie1, Ayman Abdel Raoof El-Shazly2
Departments of Radiodiagnosis1, Neurosurgery2, Ain Shams University; Egypt
ABSTRACT
Background: Recent advances in neurosurgical treatment of traumatic and birth-related brachial plexus injuries require
differentiation of pre-ganglionic nerve rootlet avulsion from postganglionic lesions. Objective: The purpose of this study was to
evaluate the efficacy of thin-section multisclice CT myelography for revealing cervicothoracic nerve rootlet avulsion in patients
with brachial plexus injuries before surgery. Methods: CT myelography for 11 patients suffering from brachial plexus injury
manifestations was performed by intrathecal injection of the lumbar subarachnoid space by water soluble contrast medium
followed by multi-slice axial CT scans then coronal, sagittal and oblique coronal reconstructions were created. The results of CT
myelography were evaluated and classified with presence of pseudo-meningocele, intradural ventral or dorsal nerve rootlets
injuries. Its diagnostic accuracy was correlated with surgical and clinical correlation in 20 cervical roots in these 11 patients
suffering from brachial plexus injury in which avulsion root injury was suspected. Results: Coronal and oblique coronal views
were superior to axial views in visualization of the nerve roots and orientation of its exact level. Sensitivity and specificity of CT
myelography for diagnosis of intradural ventral or dorsal nerve root injury with or without pseudo-meningocele in pre-ganglionic
avulsion were 95% and 95% respectively. Conclusion: The information provided by CT myelography enable to assess the roots
of the brachial plexus and added valuable data for helping to decide whether to proceed with exploration, nerve repair, and
primary reconstruction or not. [Egypt J Neurol Psychiat Neurosurg. 2011; 48(1): 63-69]
Key Words: CT myelography, brachial plexus injury, nerve root avulsion.
INTRODUCTION
Brachial plexus injury is caused by severe
traction force exerted on the upper limb, resulting in
complete or partial motor paralysis. An upper brachial
plexus lesion involves spinal nerves C5 and C6 that
leads to paralysis of the shoulder muscles and biceps.
When the damage extends to spinal nerve C7, some of
the wrist muscles are also impaired. A lower brachial
plexus lesion involves spinal nerves C8 and T1, it
involves paralysis of the forearm flexor and the
intrinsic muscles of the hand1. Injuries to the stellate
ganglion or cervical sympathetic trunk cause Horner's
syndrome. The most common cause of BPI is traffic
accidents, especially motor cycle accidents, with most
of the victims being young males. The other common
cause of BPI is birth palsy. The majority of obstetric
BPI involves the upper brachial plexus and is referred
to as Erb's or Duchenne's palsy. Lower type obstetric
BPI (Klumpke's palsy) is rare. Other traumatic causes
include accidents at work, sports injuries, incised
wounds, gunshot wounds, carrying heavy objects, and
patient mal-positioning during surgery2. Tumors,
Correspondence to Noha Mohamed Osman. 12 Mohamed Refaat
st. Heliopolis, Cairo, Egypt.
Tel.: +20101798342 Email: [email protected].
Irradiation, and congenital abnormalities such as
cervical ribs can be non-traumatic causes of brachial
plexopathy. BPI is classified into three categories: preganglionic lesions, post-ganglionic lesions, and a
combination of the two. A pre-ganglionic lesion
signifies avulsion of nerve roots, whereas a postganglionic lesion involves the nerve structure distal to
the sensory ganglion. Postganglionic lesions are further
classified into nerve ruptures and lesions in continuity
(Figure 1)3. The management of BPI depends on the
degree of damage; the site of injury; the type of
involved roots; the time interval between the injury and
the surgical procedure; and the patient’s age, sex, and
occupation. The degree of damage and the site of injury
are the most important factors4. Treatment of BPI is
either conservative or surgical. Representative surgical
procedures include neurolysis, nerve grafting, nerve
transfer, and other reconstructive procedures involving
the transplantation of various structures.
Pre-ganglionic injuries are not considered
amenable to repair; consequently, the functions of
some denervated muscles can be restored with nerve
transfers. In nerve transfer, donor nerves are attached
to the ruptured distal stumps, sacrificing the original
function of the nerve for more beneficial results in the
upper limb5. It is generally agreed that the top priority
of nerve repair is restoration of biceps muscle function
and the second goal is reanimation of shoulder
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Abdelghany, et al.: Brachial plexus injury
function6. Intercostal nerves are commonly used as the
donor nerves transferred to the musculocutaneous
nerve to regain elbow flexion. Functional recovery of
the shoulder is largely achieved with spinal accessory
nerve–suprascapular nerve transfer7. Reconstructive
surgery is indicated for infants with severe obstetric
BPI, but management details are controversial even
among professional peripheral nerve surgeons8.
Postganglionic lesions with disruption of the
nerve fiber are repaired with nerve grafting that is,
excision of the damaged segment and nerve autograft
between two nerve ends. In cases in which (a)
postganglionic lesions in continuity are non
degenerative or (b) fascicles are intact, spontaneous
recovery is usually expected with conservative
management. Lesions in continuity of degenerative type
with damaged fascicles are treated with nerve grafting.
Some surgeons doubt the benefit of neurolysis, although
this technique has been reported to be effective9.
Surgical nerve repair can provide a functional,
useful limb in most patients with BPI10. Nagano et al.7
reported that elbow flexion was restored in 82% of
patients who were under 40 years of age and underwent
intercostal nerve transfer within 6 months of injury. A
recent report demonstrated good or excellent results in
75% of suprascapular nerve reconstructions, 40% of
deltoid reconstructions, and 48% of biceps
reconstructions11. Some physicians still believe that
there is rarely a need for surgery. However, patients
with severe BPI should undergo an appropriate
reconstructive procedure before denervated muscles
become irreversibly atrophic and they are no longer
good candidates for primary nerve repair12.
The purpose of this study was to evaluate the
efficacy of thin-section multisclice CT myelography
for revealing cervicothoracic nerve rootlet avulsion in
patients with brachial plexus injuries before surgery.
Figure 1. Drawings showing the different possibilities of root avulsion (ventral or dorsal) after traction injury of the
brachial plexus. Upper left: single ventral rootlet avulsion. Upper right : single avulsion of dorsal rootlet. Lower left:
complete root avulsion. Lower right: complete root avulsion at the level of the inter-vertebral foramen (Quoted from
Carvalho et al., 1997).
PATIENTS AND METHODS
Between January 2009 and March 2010, 11
patients with brachial plexus injury were examined at
MRC CT unit. The group comprised 5 males and 6
females, ranging in age from 3 months to 50 years
(mean, 29 years). Three patients had a complete
brachial plexus palsy, three had lower brachial plexus
palsy, and five patients had upper brachial plexus
palsy. Intrathecal contrast administration was
performed by lumbar puncture employing watersoluble contrast medium using a concentration of 240
64
mg/ml Iotrolan (Isovist (R), Osaka, Japan], the dose
was 10 ml in adults and 2-3 mm in infants. Contrast
administration was successful in all patients. CT
myelography was performed within 10 minutes
afterwards. It was performed at a 16-slice helical CT
scanner (Bright Speed 16, General Electric Medical
Systems Co., Ltd., Milwaukee, USA) with the
following scanning protocol: Scanning parameters
consisted of 16 slices with 1mm x-ray beam
collimation, 0.75 sec of rotation time, and a
reconstruction interval of 0.5 mm. The patient was
positioned supine with some flexion of the cervical
spine. This position aligns lordotic curvature of the
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Abdelghany, et al.: Brachial plexus injury
cervical spine in a straight line, which is very
important to gain the good quality CT myelography in
coronal view. Helical images were transferred from
the scanner to a workstation, (Advantage Window 4.0;
GE Medical Systems, USA). The transverse (axial)
sequence was acquired to determine the status of the
ventral and dorsal roots. Coronal and sagittal views
were then reconstructed based on transverse slice.
Oblique coronal views were achieved by
reconstructions parallel to the neural foramen. The
best views for evaluating the dorsal root sleeves and
nerve roots were the 20° to 30° anterior oblique
projection. Reconstructions were
successfully
generated for all the patients. In good quality CT
myelogram on axial view, the ventral root and the
dorsal root were clearly demonstrated in a single
image (Figure 4d). The presence of the roots was
aided by comparison with the contralateral intact root.
We followed the diagnostic criteria of Yamazaki et al,
who classified CT myelographic diagnosis of root
avulsion based as follows: A(+); ventral root can be
recognized, A(-); ventral root cannot be recognized,
P(+); dorsal can be recognized, P(-); dorsal root
cannot be recognized, M(+); meningocele can be
recognized, M(-); meningocele cannot be recognized.
A nerve root was considered avulsed from the spinal
cord when either ventral or dorsal roots were
unrecognizable on axial view, while on coronal and
oblique coronal views, nerve roots were considered
avulsed when the number or size of rootlets was
decreased or the roots were absent13.
Data analysis
We compared the sensitivity, specificity, and
diagnostic accuracy between the axial CT images and
the coronal and oblique coronal CT images.
RESULTS
A hundred and ten nerve roots were examined
(10 in each patient), 20 roots proved to be avulsed by
surgical exploration and clinical tests, 16 (80%) out of
the 20 roots were identified on axial views. On coronal
and oblique coronal views, 19 (95%) roots were
diagnosed, some motion artifacts degraded image
quality in the remaining root, while 14 meningoceles
were equally seen in the axial as well as the coronal
views (Figure 2).
Nerve root avulsion was positive in 16 roots and
negative in 4 roots as identified at axial CT images.
Statistical analysis showed 80 % sensitivity, 80 %
specificity, and 80% diagnostic accuracy, with 16
true-positive findings, no true-negative findings, no
false-positive findings, and four false-negative
findings for diagnosing root avulsion.
Nerve root avulsion was positive in coronal and
oblique coronal views in 19 roots and negative in 1.
Statistical analysis showed 95 % sensitivity, 95 %
specificity, and 95 % diagnostic accuracy, with 19
true-positive findings, no true-negative findings, no
false-positive findings, and one false-negative findings
for diagnosing root avulsion.
Total number of identified nerve roots
20
18
16
Number of avulsed nerve roots
identified at axial views
14
12
10
8
6
4
Number of avulsed nerve roots
identified at coronal and oblique
coronal views
Number of meningeoceles
associated with avulsed nerve
roots
2
0
Figure 2. Avulsed nerve roots and meningeoceles identified in CT myelography.
Egypt J Neurol Psychiat Neurosurg. │Jan 2011 │ Vol 48 │ Issue 1
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Abdelghany, et al.: Brachial plexus injury
(a)
(b)
(c)
Figure 3. A one year old patient with right sided Klumpke's palsy, axial (a), coronal (b) and (c) CT myelogram
showed avulsed right C7 and C8 identified in sequential coronal scans as well as a small right C8 meningocele, the
diagnosis was confirmed intra-operatively.
(a)
(b)
(c)
Figure 4. 40 years patient with traumatic left sided brachial plexus injury, coronal (a), sagittal (b) and oblique (c) CT
myelogram showed avulsed left C5, C6 and C7 roots with left C5 and C7 meningoceles, diagnosis was confirmed by
surgery and managed by nerve transfer.
66
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Abdelghany, et al.: Brachial plexus injury
(a)
(b)
(c)
(d)
(e)
Figure 5. 40 years patient with traumatic right sided brachial plexus injury, coronal (a and b), sagittal (c) and axial (d
and e) CT myelogram showed avulsed right C6 and C7 roots with two small intra spinal meningoceles (note absence
of the nerve rootlets in the meningocele and their presence in the normal contra-lateral side), it was inoperable,
diagnosis was confirmed after conservative follow up.
DISCUSSION
Diagnostic imaging of brachial plexus injuries is
important to locate the level of the injury, as prognosis
and treatment planning depend on differentiating nerve
root avulsion from lesions distal to the sensory
ganglion. Preoperative imaging has previously been
performed
using
conventional
myelography,
computerized tomography (CT) myelography, and
magnetic resonance imaging (MRI). Doi et al reported
that overlapping coronal-oblique slices MRI technique,
which provide clear image of the rootlets and ganglia
had the same accuracy as that of CT myelography14.
MR imaging has recently been shown to be as sensitive
as CT myelography, MRI has many advantages without
considerable exposure to radiation, a possible adverse
reaction to contrast material, and the risk of lumbar
puncture. The most common findings with nerve root
avulsion are traumatic meningoceles. MRI is superior to
conventional myelography and CT myelography in
visualizing small meningoceles, which do not fill with
contrast medium in a presence of a dural scar. This MRI
technique, however, require special skill to obtain goodquality images and evaluate the images. Despite the
advent of MRI, which has replaced other imaging
techniques for evaluation of almost all disease of the
spine, conventional myelography and CT myelography
are still considered the first-choice examinations in the
evaluation of brachial plexus injury15.
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Abdelghany, et al.: Brachial plexus injury
In the 20 cases of nerve root avulsion seen in our
study, six (30%) had no associated deformity of the
subarachnoid space or pseudomeningocele. Other
studies have reported nerve root avulsion without
pseudomeningocele in 20% and only minimal
deformity of the subarachnoid space in 44% of cases 15.
The length of time required for pseudomeningocele
development is unknown and no patient in our study
was examined at two different times to determine
whether delayed pseudomeningocele formation
occurs.
CT myelography was able to show ventral and
dorsal roots exiting or entering the spinal cord at 95%
of the levels evaluated. In any evaluation of brachial
plexus injuries, all contributing cervicothoracic nerve
roots originating from C5 to T1 must be included.
Incomplete evaluation of all contributing levels limits
presurgical planning and may necessitate a more
extensive surgical exploration. We have found highresolution CT myelography with thin contiguous axial
sections to be highly useful for evaluating nerve roots
avulsions in brachial plexus birth palsies and posttraumatic brachial plexus injuries. We found a 95%
sensitivity and 95% specificity for complete nerve
rootlet avulsion with diagnostic accuracy of 95%.
Preoperative CT myelography allows more
complete injury evaluation for accurate prognosis and
surgical planning. In summary, we found highresolution CT myelography helpful when evaluating
brachial plexus injuries. We recommend the use of 1
mm contiguous axial images in infants and a 1.5 mm
slice thickness in adults with a 1 mm overlapping
interval followed by coronal, oblique and sagittal
reconstructed images. Imaging from the C3 vertebral
body to the superior aspect of T2 is required to include
all nerve roots contributions to the brachial plexus.
CT myelography is superior to conventional
myelography in visualizing the nerve roots. It is,
however, sometimes difficult to determine the exact
level of the root with axial imaging, because the roots
run obliquely16. It is difficult to detect the entire extent
of root injuries with single axial slice of the images.
CT myelography with axial view allowed
demonstration of the roots and also differentiation
between the ventral and dorsal roots (Figure 5). As the
spinal nerve roots run in oblique direction, the
continuity of some nerve roots from the cord to the
exit foramen can not be identified in axial views.
Coronal and oblique coronal views were superior to
conventional axial views in visualization of the
number and size of roots and their connection to the
cord, and in orientation of the exact level of the root
(Figures 3 and 4). Coronal views visualized the whole
image of the ventral roots, and oblique coronal views
visualized the dorsal roots17.
68
We believe that CT myelography is useful for
determining the status of the nerve roots and detecting
nerve root avulsion, although diagnostic utility was
not significantly different. In this study, we reviewed
twenty roots from C5 root down to D1 root.
Exploration of the all the roots was not routinely
performed, since the nerve graft is not effective in the
lower roots. Brachial plexus exploration cannot reveal
intraforaminal rootlet lesions unless laminectomy is
performed. Intraoperative nerve action potentials
obtained at the proximal cervical root attempt to
evaluate the intraspinal status of the roots
extraspinally.
Conclusion
CT myelography, in spite of its invasiveness, is
still indispensable for preoperative evaluation of
cervical nerve root avulsion of brachial plexus injury
because of its precise delineation of the nerve roots
integrity.
[Disclosure: Authors report no conflicts of interest]
REFERENCES
1.
2.
3.
4.
5.
6.
7.
8.
9.
Nagano A. Treatment of brachial plexus injury. J
Orthop Sci. 1998; 3: 71-80.
Nagano A, Ochiai N, Sugioka H, Hara T, Tsuyama
N. Usefulness of myelography in brachial plexus
injuries. J Hand Surg (Br). 1989; 14: 59-64.
Carvalho GA, Nikkhah G, Matthies C, Penkert G,
Samii M. Diagnosis of root avulsions in traumatic
brachial plexus injuries: value of computerized
tomography myelography and magnetic resonance
imaging. J Neurosurg. 1997; 86:69-76.
Kline DG. Surgical repair of brachial plexus injury.
J Neurosurg. 2004; 101: 361-64.
Belzberg AJ, Dorsi MJ, Storm PB, Moriarity JH.
Surgical repair of brachial plexus injury: a
multinational survey of experienced peripheral
nerve surgeons. J Neurosurg. 2004; 101:365–76.
Millesi H. Brachial plexus injuries. In: Jupiter JB,
editor. Flynn’s hand surgery. 4th ed. Baltimore,
Md: Williams & Wilkins; 1991, pp. 457-63.
Nagano A, Tsuyama N, Ochiai N, Hara Tand,
Takahashi M. Direct nerve crossing with the
intercostals nerve to treat avulsion injuries of the
brachial plexus. J Hand Surg (Am). 1989; 14: 980-5.
Gutowski KA, Orenstein HH. Restoration of elbow
flexion after brachial plexus injury: the role of
nerve and muscle transfers. Plast Reconstr Surg.
2000; 106: 1348-57.
Terzis JK, Vekris MD, Soucacos PN. Outcomes of
brachial plexus reconstruction in 204 patients with
devastating paralysis. Plast Reconstr Surg. 1999;
104: 1221-40.
Egypt J Neurol Psychiat Neurosurg. │Jan 2011 │ Vol 48 │ Issue 1
Abdelghany, et al.: Brachial plexus injury
10.
11.
12.
13.
14.
Rankine JJ. Adult traumatic brachial plexus injury.
Clin Radiol. 2004; 59: 767-74.
Malessy MJ, de Ruiter GC, de Boer KS, Thomeer
RT.
Evaluation
of
suprascapular
nerve
neurotization after nerve graft or transfer in the
treatment of brachial plexus traction lesions. J
Neurosurg. 2004; 101: 377-89.
Narakas A. Brachial plexus surgery. Orthop Clin
North Am. 1981; 12: 303-23.
Yamazaki H, Doi. K Hattori, K, Sakamoto S.
Computerized tomography myelography with
coronal and oblique coronal view for diagnosis of
nerve root avulsion in brachial plexus injury.
Journal of Brachial Plexus and Peripheral Nerve
Injury 2007, 2: 16-21.
Doi K, Otsuka K, Okamoto Y, Fujii H, Hattori Y,
Baliarsing AS. Cervical nerve root avulsion in
brachial plexus injuries: magnetic resonance
15.
16.
17.
imaging classification and comparison with
myelography and computerized tomography
myelography. J Neurosurg 2002, 96: 277-84.
Yoshikawa T, Hayashi N, Yamamoto S Tajiri Y,
Yoshioka N, Masumoto T, et al. Brachial Plexus
Injury: Clinical Manifestations, Conventional
Imaging Findings, and the Latest Imaging
Techniques. Radio Graphics. 2006; 26: S133-43.
Walker AT, Chaloupka JC, de Lotbiniere AC,
Wolfe SW, Goldman R, Kier EL. Detection of
nerve rootlet avulsion on CT myelography in
patients with birth palsy and brachial plexus injury
after trauma. AJR Am J Roentgenol. 1996; 167:
1283-7.
Tsuchiya K, Katase S, Aoki C, Hachiya J.
Application of multi-detector row helical scanning
to postmyelographic CT. Eur Radiol. 2003; 13:
1438-43.
‫الملخص العزبي‬
‫دور األشعت المقطعيت متعذدة المقاطع مع حقن صبغه فى السائل النخاعى‬
‫فى تشخيص انقطاع جذور األعصاب فى إعطاب أعصاب الذراعين‬
‫إن عمل أشعه مقطعيه مع حقن صبغه بالسائل النخاعى تساعد عمى توضيح مكان ومدى سالمة خذور االعصاب الخارجه من الحبل‬
.‫ ان الهدف من البحث هو دراسة الترابط بين نتائج هذا الفحص مع ما يكتشفه الجراح فى مكان االصابة عند التدخل الجراحى‬،‫الشوكى‬
‫ مرضى يعانون من اعطاب فى االعصاب المغذية لمذراعين ويحتاج الجراح لمعرفة هل االصابه كانت قطع فى‬11 ‫لقد أجرى البحث عمى‬
.‫جذوراالعصاب فى النخاع الشوكى او هى بعيدة عنه الختالف طرق العالج فى الحالتين‬
‫لقد تم عمل اشعه مقطعيه لممرضى بعد حقن الصبغه فى السائل النخاعى و اخذ مقاطع افقيه ثم اعادة تركيب المقاطع فى المحاور الطوليه‬
‫والرأسيه والمائ مه ثم التأكد من سالمة الجذور أو انقطاعها واذا تم تكوين كيس زاللى نخاعى أو ال ثم مقارنة النتأئج بما يكتشفه جراح االعصاب‬
.‫اثناء محاولة اصالح تمك االعطاب‬
‫لقد استنتج الباحثون ان تركيب الصور فى المحاور الطوليه و المائمه يعطى معمومات أدق عن جذور االعصاب وعالقتها بالحبل الشوكى‬
.‫ عند مقارنتها بنتائج الكشف الجراحى‬%59 ‫عن المقاطع االفقيه و ان تمك المعمومات دقيقه بنسبة‬
‫لقد أوضح البحث ان االشعة المقطعيه متعددة المقاطع مع حقن الصغه فى السائل النخاعى تعطى معمومات هامه ودقيقه عن حالة جذور‬
.‫االعصاب و هل يمكن لمجراح اصالح تمك االعطاب أو ال‬
Egypt J Neurol Psychiat Neurosurg. │Jan 2011 │ Vol 48 │ Issue 1
69