SHORT REPORTS
MITOCHONDRIAL RESPIRATORY CHAIN AND CREATINE KINASE
ACTIVITIES IN mdx MOUSE BRAIN
LISIANE TUON, PhD,1 CLARISSA M. COMIM, MSc,1 DAINE B. FRAGA, BSc,2 GISELLI SCAINI, BSc,2
GISLAINE T. REZIN, MSc,2 BRUNA R. BAPTISTA, BSc,2 EMILIO L. STRECK, PhD,2 MARIZ VAINZOF, PhD,3
and JOÃO QUEVEDO, MD, PhD1
1
Laboratório de Neurociências and Instituto Nacional de Ciência e Tecnologia Translacional em Medicina,
Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul
Catarinense, 88806-000 Criciúma, SC, Brazil
2
Laboratório de Fisiopatologia Experimental and Instituto Nacional de Ciência e Tecnologia Translacional em Medicina,
Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul
Catarinense, Criciúma, SC, Brazil
3
Human Genome Research Center, Biosciences Institute, University of São Paulo, SP, Brazil
Accepted 26 August 2009
ABSTRACT: In this study we investigated energy metabolism
in the mdx mouse brain. To this end, prefrontal cortex, cerebellum, hippocampus, striatum, and cortex were analyzed. There
was a decrease in Complex I but not in Complex II activity in all
structures. There was an increase in Complex III activity in
striatum and a decrease in Complex IV activity in prefrontal cortex and striatum. Mitochondrial creatine kinase activity was
increased in hippocampus, prefrontal cortex, cortex, and striatum. Our results indicate that there is energy metabolism dysfunction in the mdx mouse brain.
Muscle Nerve 41: 257–260, 2010
The dystrophin-deficient mdx mouse is an established animal model of Duchenne muscular dystrophy (DMD), a human neurodegenerative disease.
This protein is located in the inner side of the cell
membrane in muscle and brain cells.1 Brain dystrophin is enriched in the postsynaptic densities of
pyramidal neurons. These are specialized regions
of the subsynaptic cytoskeletal network that are
critical for synaptic transmission and plasticity.2
The lack of dystrophin in the brain has been correlated with impaired cognitive function3; however,
the nature, magnitude, and biological basis of the
cognitive deficits still remain unclear.
The impairment in energy production caused
by mitochondrial dysfunction has been found in
some neurodegenerative diseases such as dementia, Alzheimer’s, and Parkinson’s diseases, all culminating in some level of cognitive impairment.4
The mitochondrial respiratory chain is responsible
for oxidative phosphorylation for production of
adenosine triphosphate (ATP). Tissues with high
energy demands, such as the brain, contain a large
number of mitochondria and are therefore more
susceptible to the effects of reduced of aerobic
Abbreviations: ADP, adenosine diphosphate; ATP, adenosine triphosphate; BDNF, brain-derived neuronal factor; mi-CK, mitochondrial creatine
kinase
Key words: mdx mouse; mitochondrial respiratory chain; creatine kinase;
brain
Correspondence to: J. Quevedo; e-mail: [email protected]
C 2010 Wiley Periodicals, Inc.
V
Published online 15 January 2010 in Wiley
interscience.wiley.com). DOI 10.1002/mus.21559
Metabolism in mdx Mouse Brain
InterScience
(www.
energy metabolism.4 Alteration in mitochondrial
function could decrease ATP production and elevate mitochondrial creatine kinase (mi-CK) activity,
which works as an effective buffering system of cellular ATP levels.5
The role of energy metabolism in the mdx
mouse brain still remains unclear. In this study we
investigated the mitochondrial respiratory chain
complexes (I, II, III, and IV) and mi-CK activities
in the mdx mouse brain.
MATERIALS AND METHODS
Animals. We used male dystrophic
(mdx) and normal C57BL10 mice (3 months: wildtype n ¼ 5, mdx
n ¼ 5) from the Human Genome Research Center,
Biosciences Institute, University of São Paulo, Brazil. The mice were killed by decapitation, and prefrontal cortex, cerebellum, hippocampus, striatum,
and cortex were removed and stored for analyses
of mitochondrial respiratory chain and mi-CK
activities.
All experimental procedures involving animals
were performed in accordance with the NIH Guide
for the Care and Use of Laboratory Animals and were
approved by the Animal Care and Experimentation
Committee of UNESC, Brazil.
Mitochondrial Respiratory Chain Enzyme Activities.
Brain structures were homogenized in SETH
buffer for determination of mitochondrial respiratory chain enzyme activities (Complexes I, II, II–
III, and IV). NADH dehydrogenase (Complex I)
was evaluated by the rate of NADH-dependent ferricyanide reduction at 420 nm. Complex II activity
was measured by following the decrease in absorbance due to the reduction of 2,6-dichloroindophenol (DCIP) at 600 nm. Complex II–III activity was
measured by cytochrome c reduction from succinate. The activity of cytochrome c oxidase (Complex IV) was assayed by following the decrease in
absorbance due to the oxidation of previously
reduced cytochrome c at 550 nm. The activities of
MUSCLE & NERVE
February 2010
257
Table 1. Mitochondrial respiratory chain activity in mdx mouse brain.
Groups
Hippocampus
Wt
mdx
Prefrontal Cortex
Wt
mdx
Cortex
Wt
mdx
Striatum
Wt
mdx
Cerebellum
Wt
mdx
Complex I
[nmol/min.mg
protein]
Complex II
[nmol/min.mg
protein]
Complex III
[nmol/min.mg
protein]
Complex IV
[nmol/min.mg
protein]
Creatina Kinase activity
[units/mg protein]
171.36 6 27.93
34.36 6 5.06*
1.72 6 0.34
1.99 6 0.41
0.77 6 0.098
1.82 6 0.54
55.62 6 12.01
75.11 6 9.35
2.85 6 0.15
4.82 6 0.21*
170.15 6 22.98
40.09 6 4.09*
1.37 6 0.13
1.96 6 0.44
0.57 6 0.075
1.05 6 0.19
273.13 6 62.97
59.73 6 13.89*
3.51 6 0.28
7.37 6 0.34*
131.07 6 20.6
43.1 6 7.36*
1.77 6 0.41
3.52 6 0.72
0.68 6 0.096
2.22 6 0.8
78.27 6 18.64
98.93 6 30.93
2.24 6 0.055
5.14 6 0.47*
148.68 6 23.07
40.93 6 6.25*
1.83 6 0.34
2.2 6 0.33
0.46 6 0.14
1.52 6 0.27*
325.36 6 102.99
69.9 6 5.76*
1.92 6 0.33
4.43 6 0.37*
128.8 6 20.01
30.97 6 3.78*
2.25 6 0.48
2.41 6 0.47
0.58 6 0.13
1.27 6 0.37
141.19 6 78.63
62.54 6 24.3
3.53 6 0.16
4.36 6 0.81
Decreased Complex I activity is shown in all structures. In Complex II there was no alteration of its activity in all structures. Complex III increased its activity
only in striatum and Complex IV decreased its activity in prefrontal cortex and striatum. In mi-CK activity there was increased CK activity in hippocampus,
prefrontal cortex, cortex, and striatum compared with wildtype mouse Bars represent means 6 SD of 5 mice.
*P < 0.05 vs. wildtype according to Student’s t-test.
the mitochondrial respiratory chain complexes are
expressed as nmol/min mg protein.8
Creatine Kinase Activity. Creatine kinase activity
was measured in brain homogenates pretreated with
lauryl maltoside. The reaction mixture consisted of
Tris-HCl, pH 7.5, containing phosphocreatine,
MgSO4, and protein in a final volume of 100 ml.
The reaction was started by the addition of adenosine diphosphate (ADP) and reduced glutathione.
The reaction was stopped after 10 min by the addition of p-hydroxymercuribenzoic acid. The creatine
formed was estimated according to the colorimetric
method. The color was developed by the addition of
a-naphthol and diacetyl in a final volume of 1 ml
and read spectrophotometrically at 540 nm. The
results are expressed as units/min mg protein.8
Statistical Analysis. All data are presented as
mean 6 SD. Differences among experimental groups
were determined by Student’s t-test. P values less
than 0.05 were considered statistically significant.
RESULTS
The table shows mitochondrial respiratory chain
(Complex I, II, III, and IV) activity in mdx mouse
brain. Complex I (Fig. 1A) decreased its activity in
hippocampus (t ¼ 4.825; df ¼ 4.263; P ¼ 0.007),
prefrontal cortex (t ¼ 5.570; df ¼ 5; P ¼ 0.004),
cortex (t ¼ 4.507; df ¼ 4.585; P ¼ 0.010), striatum
(t ¼ 4.507; df ¼ 4.585; P ¼ 0.008), and cerebellum
(t ¼ 4.803; df ¼ 4.286; P ¼ 0.007). Complex II activity (Fig. 1B) remained unaltered in all brain
structures. In Complex III (Fig. 1C) there was an
increase of activity only in striatum (t ¼ 3.439; df
¼ 6.010; P ¼ 0.014). Complex IV (Fig. 1D)
258
Metabolism in mdx Mouse Brain
decreased its activity in prefrontal cortex (t ¼
3.309; df ¼ 4.389; P ¼ 0.026) and striatum (t ¼
2.476; df ¼ 8; P ¼ 0.038). All results were compared with wildtype mice. In mi-CK activity (Fig.
1E) there was an increase in hippocampus (t ¼
7.266; df ¼ 8; P ¼ 0.0001), prefrontal cortex (t ¼
8.608; df ¼ 8; P ¼ 0.0001), cortex (t ¼ 4.983; df
¼ 8; P ¼ 0.0001), and striatum (t ¼ 4.983; df ¼
8; P ¼ 0.001) compared with the wildtype mouse.
DISCUSSION
In mdx mouse skeletal muscle, studies indicate dysfunction in mitochondria and changes in mitochondrial protein composition. Enzymatic analysis
of skeletal muscle showed an 50% decrease in
the activity of all respiratory chain-linked enzymes
in quadriceps muscle.9 Mdx mouse muscle mitochondria had only 60% of maximal respiratory activity and contained only 60% of hemoproteins
of the mitochondrial inner membrane.9 Similar
findings were observed in a skeletal muscle biopsy
of a DMD patient.10 The data demonstrated above
suggest that a specific decrease in the amount of
all mitochondrial inner membrane enzymes, most
probably as a result of Ca2þ overload of muscle
fibers, is the reason for the bioenergetic deficits in
dystrophin-deficient skeletal muscle.9 Other studies
demonstrated that in isolated mitochondria from
quadriceps muscle of the mdx mouse there was elevated calcium content and decreased respiratory
control ratios with the NAD-linked substrates pyruvate/malate.6 In addition, DMD patients and the
mdx mouse model appear to have impaired intracellular calcium homeostasis in the central nervous
system (CNS), with disrupted multiple protein–
MUSCLE & NERVE
February 2010
protein interactions that normally promote information transfer and signal integration from the
extracellular environment to the nucleus within
regulated microdomains.11 The bioenergetic
abnormalities reported in DMD brain have also
been documented in the mdx mouse, with an
increased inorganic phosphate-to-phosphocreatine
ratio, increased intracellular brain pH, alteration in
metabolism of glucose, and abnormally clustered
GABAA receptors.11 Lack of dystrophin affects neuronal excitability, long-term synaptic plasticity,15
and metabolic and physiological insults15 cause
neuronal death16 and decreased striatum brainderived neuronal factor (BDNF) protein levels.19
In this regard, a number of neurological diseases are associated with neurodegeneration and
neuronal death, associated with cognitive impairment17 caused primarily by abnormal brain energy
metabolism and mitochondrial dysfunction.18 We
demonstrated mitochondrial dysfunction in the
mdx mouse brain. Alterations in mitochondrial
function could decrease ATP production.5 We
demonstrated an increase in mi-CK activity in hippocampus, cortex, striatum, and prefrontal cortex
in mdx mouse brain. These areas are involved in
memory processing, and the lack of dystrophin in
brain structures such as hippocampus and cortex
has been associated with impaired cognitive functioning, because brain dystrophin is abundant
principally in the hippocampus.3 At the cellular
level, the absence of dystrophin in the mdx mouse
causes altered calcium homeostasis that may be
associated with a decrease in the amount of all
mitochondrial inner membrane enzymes as well as
skeletal muscle.9 Furthermore, creatine kinase
plays a central role in the metabolism of highenergy-consuming tissues such as brain. It catalyzes
the reversible transfer of the phosphoryl group
from phosphocreatine to ADP, regenerating
ATP.20 Therefore, the increased ATP-regenerating
capacity via the mi-CK reaction might be related to
a delay in ATP depletion and, thereby protect the
brain from damage.20 The decrease in mi-CK activity is associated with a neurodegenerative pathway
that results in neuronal loss.21,22 Another study
showed that, in skeletal muscle, the absence of dystrophin is associated with rearrangement of the
intracellular energy and feedback signal transfer
systems between mitochondria and ATPases.7
Recently, we observed (1) reduced lipid peroxidation in striatum and protein peroxidation in cerebellum and prefrontal cortex; (2) increased superoxide dismutase activity in cerebellum, prefrontal
cortex, hippocampus, and striatum; and (3)
reduced catalase activity in striatum.23 These findings may be involved in the alteration of energy
metabolism in the mdx mouse brain.
Metabolism in mdx Mouse Brain
In conclusion, we present evidence for dysfunction in mitochondrial respiratory chain activity and increased mi-CK activity in the brain of
the mdx mouse. This increase in CK activity could
be causing a protective effect against cellular damage, since it functions as a buffering system for
cellular ATP levels. One important limiting factor
in this study was the number of animals that, in a
few structures, demonstrated a statistical tendency. However, even with the limited number of
animals, this report is a pioneer in showing
energy impairment in the brain of the mdx
mouse. Further studies are needed to better elucidate neurobiological alterations in the mdx mouse
brain.
This research was supported by grants from CNPq, FAPESC, Instituto Cérebro e Mente, and UNESC (to J.Q. and E.L.S.), all from
Brazil. J.Q., E.L.S., and M.V. are CNPq Research Fellows. C.M.C. is
holder of a CNPq Studentship. L.T. and C.M.C. conceived of this
study, participated in the design of the study, and drafted the article, collaborating in equal proportions; D.B.F., D.S., G.T.R., and
B.R.B. participated in the design of the study and performed
experimental analyses; E.L.S., M.V., and J.Q. participated in the
design of the study and drafted the article.
REFERENCES
1. Blake DJ, Kröger S. The neurobiology of Duchenne muscular dystrophy: learning lessons from muscle? Trends Neurosci 2000;23:
92–99.
2. Lidov HG, Byers TJ, Watkins SC, Kunkel LM. Localization of dystrophin to postsynaptic regions of central nervous system cortical neurons. Nature 1990;348:725–728.
3. Anderson JL, Head SI, Rae C, Morley JW. Brain function in Duchenne muscular dystrophy. Brain 2002;125:4–13.
4. Heales SJ, Bolaños JP, Stewart VC, Brookes PS, Land JM, Clark JB.
Nitric oxide, mitochondria and neurological disease. Biochim Biophys Acta 1999;1410:215–228.
5. Wyss M, Kaddurah-Daouk R. Creatine and creatinine metabolism.
Physiol Rev 2000;3:1108–1182.
6. Glesby MJ, Rosenmann E, Nylen EG, Wrogemann K. Serum CK, calcium, magnesium, and oxidative phosphorylation in mdx mouse
muscular dystrophy. Muscle Nerve 1988;11:852–856.
7. Braun U, Paju K, Eimre M, Seppet E, Orlova E, Kadaja L, et al. Lack
of dystrophin is associated with altered integration of the mitochondria and ATPases in slow-twitch muscle cells of mdx mice. Biochim
Biophys Acta 2001;1505:258–270.
8. Comim CM, Rezin GT, Scaini G, Di-Pietro PB, Cardoso MR, Petronilho FC, et al. Mitochondrial respiratory chain and creatine kinase
activities in rat brain after sepsis induced by cecal ligation and perforation. Mitochondrion 2008;8:313–318.
9. Kuznetsov AV, Winkler K, Wiedemann FR, von Bossanyi P, Dietzmann K, Kunz WS. Impaired mitochondrial oxidative phosphorylation in skeletal muscle of the dystrophin-deficient mdx mouse. Mol
Cell Biochem 1998;183:87–96.
10. Scholte HR, Luyt-Houwen IE, Busch HF, Jennekens FG. Muscle mitochondria from patients with Duchenne muscular dystrophy have a
normal beta oxidation, but an impaired oxidative phosphorylation.
Neurology 1985;35:1396–1397.
11. Rae C, Blair DH, Griffin JL, Bothwell JHF, Bubb Wa, Maitland A,
et al. Brain biochemical abnormalities associated with lack of dystrophin; studies in the mdx mouse. Neuromuscul Disord 2002;12:
121–129.
12. Sogos V, Curto M, Reali C, Gremo F. Developmentally regulated
expression and localization of dystrophin and utrophin in the
human fetal brain. Mech Ageing Dev 1992;123:455–462.
13. Mehler MF, Haas KZ, Kessler JA, Stanton PK. Enhanced sensitivity of
hippocampal pyramidal neurons from mdx mouse to hypoxiainduced loss of synaptic transmission. Proc Natl Acad Sci U S A
1992;89:2461–2465.
14. Haenggi T, Fritschy JM. Role of dystrophin and utrophin for assembly and function of the dystrophin glycoprotein complex in nonmuscle tissue. Cell Mol Life Sci 2006;63:1614–1631.
15. Culligan K, Ohlendieck K. Diversity of the brain dystrophin-glycoprotein complex. J Biomed Biotechnol 2002;2:31–36.
MUSCLE & NERVE
February 2010
259
16. Jagadha V, Becker LE. Brain morphology in Duchenne muscular dystrophy: a Golgi study. Pediatr Neurol 1988;4:87–92.
17. Mancuso C, Scapagini G, Curro D, Giuffrida Stella AM, De Marco C,
Butterfield DA, et al. Mitochondrial dysfunction, free radical generation and cellular stress response in neurodegenerative disorders.
Front Biosci 2007;12:1107–1123.
18. Navarro A, Boveris A. The mitochondrial energy transduction system and the aging process. Am J Physiol Cell Physiol 2007;292:
C670–C686.
19. Comim CM, Tuon L, Stertz L, Vainzof M, Kapczinski F, Quevedo J.
Striatum brain-derived neurotrophic factor levels are decreased in
dystrophin-deficient mice. Neurosci Lett 2009;459:66–68.
20. Lipton P, Whittingham TS. Reduced ATP concentration as a basis
for synaptic transmission failure during hypoxia in the in vitro
guinea-pig hippocampus. J Physiol 1982;325:51–65.
21. Green DE, Fry M. On reagents that convert cytochrome oxidase
from an inactive to an active coupling state. Proc Natl Acad Sci U S
A 1980;77:1951–1955.
22. Brustovetsky N, Brustovetsky T, Dubinsky JM. On the mechanisms of
neuroprotection by creatine and phosphocreatine. J Neurochem
2001;76:425–434.
23. Comim CM, Cassol OJ Jr, Constantino LC, Constantino CS, Petronilho
F, Tuon L, et al. Oxidative variables and antioxidant enzymes activities
in the mdx mouse brain. Neurochem Int 2009 [Epub ahead of print].
THE ILLUSION OF SEVERE CARPAL TUNNEL SYNDROME (CTS)
LUDWIG GUTMANN, MD and CHRISTOPHER NANCE, MD
Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506-9180, USA
Accepted 12 August 2009
ABSTRACT: Thenar atrophy occurs in patients with severe
carpal tunnel syndrome (CTS) of long-standing duration. In this
report we present a young woman with mild bilateral CTS,
based on electrophysiological studies, in whom marked thenar
atrophy was on a congenital basis related to the VATER association (vertebral anomalies, anal atresia, tracheoesophageal fistula, and radial or renal abnormalities).
Muscle Nerve 41: 260–261, 2010
Carpal tunnel syndrome (CTS) is a common compressive distal median neuropathy that is easily
diagnosed on the basis of clinical and electrophysiological features. Most patients present with intermittent paresthesias of the hands precipitated by
sleeping and activities involving the use of the
hands. Physical findings are usually limited, and
thenar atrophy is a late occurrence of the disorder
that reflects its severity. We present a young woman
who appeared to have severe CTS in whom the thenar atrophy was related to another disorder.
CASE REPORT
A 26-year-old hospital unit clerk had tingling in
both hands for the previous 6 months. The symptoms were intermittent and associated with severe
pain in the thumb. The tingling involved only the
first 3 fingers of both hands. It would awaken her
at night and was precipitated by driving her car.
Prominent thenar atrophy, first noted by the referring neurologist, was present bilaterally. The
symptoms interfered with her ability to use her
Abbreviations: APB, abductor pollicis brevis; CHARGE, coloboma of the
eye/central nervous system anomalies, heart defects, atresia of the nasal
choanae, retardation of growth and/or development, genital and/or urinary
defects (hypogonadism), and ear anomalies and/or deafness; CTS, carpal
tunnel syndrome; EMG, electromyography; MRI, magnetic resonance
imaging; VATER, vertebral anomalies, anal atresia, tracheoesophageal
fistula, and radial or renal abnormalities; VACTERL, vertebral and cardiac
anomalies, anal atresia, tracheoesophageal fistula, and radial/renal/limb
abnormalities
Key words: carpal tunnel syndrome; thenar atrophy; VATER association;
VACTERL association; tracheoesophageal fistula; anal atresia
Correspondence to: L. Gutmann; e-mail: [email protected]
Disclosure: The authors report no conflicts of interest.
C 2009 Wiley Periodicals, Inc.
V
Published online 13 November 2009 in Wiley InterScience (www.
interscience.wiley.com). DOI 10.1002/mus.21547
260
Illusion of a Severe CTS
hands, and she was worried that she might not
be able to unlock her door.
The symptoms occurred on a background of a
great deal of anxiety and asthma. She was born
prematurely with an imperforate anus and a tracheoesophageal fistula that required reconstructive
surgery. Her mother did not have diabetes mellitus. She also had subsequent surgery for endometriosis and an appendectomy.
On examination, she was neat and anxious with
severe thenar weakness and atrophy bilaterally
(Fig. 1A). She has a lifelong inability to flex her
left thumb. The Tinel sign was present bilaterally
while the Phalen sign was present only on the left.
The remainder of the neurological examination
was within normal limits.
Palmar sensory latencies of the median nerves
(stimulating at the mid-palm and recording 8 cm
proximally at the wrist) were 2.25 ms on the right
and 3.05 ms on the left (normal < 2.2 ms), while
their amplitudes were normal at 83 lV and 68 lV,
respectively (normal > 50 lV). A negative potential could not be recorded from the abductor pollicis brevis (APB) when stimulating the motor axons
of the median nerves. Small compound muscle
action potentials with amplitudes of 0.7 and 0.4
mV (normal > 4.2 mV), respectively, were
recorded from the flexor pollicis brevis muscles
bilaterally. Distal motor latencies were 4.85 ms on
the right and 4.50 ms on the left (normal < 4.2
ms). Ulnar nerve conduction studies were normal.
Needle electromyography (EMG) of both ABP
muscles showed no fibrillation potentials or motor
unit potentials. Needle examination of ulnar innervated muscles was normal.
Magnetic resonance imaging (MRI) of the
hands showed the absence of most of the thenar
muscles (Fig. 1B) and hypoplasia of several tendons. X-rays of the hands and wrists (data not
shown) demonstrated hypoplasia of the scaphoid
bones (more prominent on the left) and mildly
small thumbs.
MUSCLE & NERVE
February 2010
FIGURE 1. Severe thenar atrophy is shown in both hands of the patient (A) and on the MRI (B) of 1 hand (arrow).
DISCUSSION
The patient’s history and findings suggested the presence of a prominent CTS. The electrophysiological
changes of mild prolongation of distal motor and palmar sensory latencies in both median nerves were not
consistent with the pronounced thenar muscle atrophy and small thenar compound muscle action potentials. The patient had a second disorder, the VATER
association (vertebral anomalies, anal atresia, tracheoesophageal fistula, and radial or renal abnormalities),
which was responsible for the abnormalities of the thenar muscles. This created the illusion that her distal
median neuropathies were severe rather than mild.
Needle EMG of the ABP muscles, showing no
fibrillation potentials or motor unit potentials, was
consistent with a congenital absence of these
muscles. MRI of the hands showed loss of the
thenar muscles and hypoplasia of several tendons.
X-rays of the hands and wrists demonstrated bony
hypoplasia consistent with radial limb anomalies.
The VATER association refers to a series of
congenital anomalies that include: (1) vertebral
anomalies, (2) anal atresia, (3) tracheoesophageal
fistula, and (4) radial or renal abnormalities. It has
been expanded to the VACTERL association to
include cardiac and limb abnormalities.
In a study of 46 patients with the VATER association, the most common defects were tracheoesophageal malformations (67.4%) and congenital
heart defects (78.3%). Additional common abnormalities were vertebral anomalies (58.7%), imperforate anus (56.5%), and renal dysplasia or agenesis (60.9%). Radial dysplasias were less frequent
(15.2%). Infants with forearm anomalies include
radial dysplasia or agenesis with absent, malformed, or extra thumbs.1,2 Additional reports
describe absent scaphoid, hypoplastic thumb and
thenar muscles, and absent flexor pollicis longus,3
and shortened first metacarpal bone.1
Our patient had many of the features of
VATER association, the most notable of which
were a history of imperforate anus and tracheoIllusion of a Severe CTS
esophageal fistula and radial abnormalities, including hypoplastic tendons and bony abnormalities of
the thumbs and scaphoid bones. She declined spinal X-rays and renal ultrasound. The bilateral thenar atrophy was likely on the same congenital basis
and was only noted by the patient when it was
pointed out to her.
The VATER/VACTERL association is a rare disorder that occurs sporadically and shows a wide
spectrum of congenital abnormalities. Its origin is
not known. Although McMullen et al.4 described a
mildly increased risk to relatives of patients with
tracheoesophageal fistulae for other VACTERL
malformations, other epidemiological studies of
families and twins have not implicated a major
role of genetic factors in most cases.5,6
In contrast, there are several syndromes that
resemble the VATER/VACTERL association that
are caused by single-gene disorders. They include
Feingold syndrome, CHARGE syndrome (coloboma of the eye/central nervous system anomalies,
heart defects, atresia of the nasal choanae, retardation of growth and/or development, genital and/
or urinary defects [hypogonadism], and ear
anomalies and/or deafness), 22q11 deletion syndrome, Fanconi anemia with VACTERL association, Townes-Brocks syndrome, and Pallister-Hall
syndrome. Each has some clinical features in common with the VATER/VACTERL association and
each has a single-gene abnormality.5,6
REFERENCES
1. Quan L, Smith DW. The VATER association. J Pediatr 1973;82:104–107.
2. Weaver DD, Mapstone CL, Yu P. The VATER association. Am J Dis
Child 1986;140:225–229.
3. Swaminathan R, Lapsia S, Scrinibasan M. Congenital absence of scaphoid and flexor pollicis longus. A case report. Ortop Traumatol
Rehabil 2003;5:527–529.
4. McMullen KP, Karnes PS, Moir CR, Michels VV. Familial occurrence
of tracheoesophageal fistula and associated malformations. Am J
Med Genet 1996;63:525–528.
5. Genevieve D, Pontual L, Amiel J, Sarnacki S, Lyonnet S. An overview of
isolated and syndromic oesophageal atresia. Clin Genet 2007;71:392–399.
6. Shaw-Smith C. Oesophageal atresia, tracheo-oesophageal fistula, and
VACTERL association: review of genetics and epidemiology. J Med
Genet 2006;43:545–554.
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261
SOMATOSENSORY EVOKED POTENTIAL MONITORING OF THE
BRACHIAL PLEXUS DURING A WOODWARD PROCEDURE FOR
CORRECTION OF SPRENGEL’S DEFORMITY
KEVIN G. SHEA, MD,1 PETER J. APEL, MD,2 LARRY D. SHOWALTER, MD,1 and WILLIAM L. BELL, MD3
1
Intermountain Orthopaedics, Boise, Idaho, USA
Department of Orthopaedic Surgery, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem,
North Carolina 27157, USA
3
Department of Neurology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
2
Accepted 12 August 2009
ABSTRACT: Sprengel’s deformity is the most common congenital deformity of the shoulder. A known complication of correcting this deformity is brachial plexus palsy. In this study we
used somatosensory evoked potential (SSEP) monitoring during
correction of a Sprengel’s deformity and identified an early iatrogenic brachial plexus injury. The operation was modified, and
permanent nerve injury was avoided. We recommend that
SSEP monitoring be considered in procedures to correct Sprengel’s deformity.
Muscle Nerve 41: 262–264, 2010
Sprengel’s deformity is a rare congenital deformity of the shoulder.1 Children with Sprengel’s deformity have a noticeable elevation of the affected
shoulder and a hypoplastic and medially rotated
scapula. Although functional impairment may be
present, an unsightly appearance is usually the presenting complaint.2
Due to hypoplasia of the scapula, the goal of
surgical correction is to achieve equal height of
the scapular spine, rather than equal height of the
inferior angle. A known complication of caudalization of the scapula is brachial plexus palsy.3–6 Clavicular osteotomy and/or morselization has been
recommended to avoid this complication.7,8
Somatosensory evoked potential (SSEP) monitoring provides real-time data on neuropraxia and
is a useful indicator of intraoperative brachial
plexus injury. SSEP and other intraoperative
neuromonitoring techniques have been used
extensively to detect and prevent nerve injury during various surgical procedures.9,10 Although SSEP
has been used for other upper extremity procedures,11 to our knowledge, the use of SSEP during
surgical correction of Sprengel’s deformity has not
been reported.
CASE REPORT
A 4-year-old boy with isolated Sprengel’s deformity
underwent left clavicular osteotomy and morselization followed by a left-sided Woodward procedure.
SSEP monitoring of the brachial plexus was performed with a Nicolet Viking NT v5.2q electrophysAbbreviation: SSEP, somatosensory evoked potential
Key words: brachial plexus; Sprengel’s deformity; SSEP; Woodward
procedure; intraoperative monitoring
Correspondence to: P.J. Apel; e-mail: [email protected]
C 2010 Wiley Periodicals, Inc.
V
Published online 15 January 2010 in Wiley
interscience.wiley.com). DOI 10.1002/mus.21545
262
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InterScience
(www.
iology unit. The left and right ulnar nerves were
individually stimulated at the wrist with a square
wave of 200-ls duration at a rate of 4.7 per second
and stimulation intensity of 15–20 lV. Multiple
cortical and subcortical measurements were
obtained using the following recording parameters:
(1) 30-ms windows, with high-frequency filter of
1000 HZ and low-frequency filter of 30 HZ; and (2)
cortical (Cp4–Cp3), cervical (Cs2–Fpz), cervical
(Cs5–Fpz), and axillary (Axp–Axd) derivations for
left ulnar stimulation, and cortical (Cp3–Cp4), cervical (Cs2–Fpz), cervical (Cs5–Fpz), and axillary
(Axp–Axd) derivations for right ulnar stimulation.
Baseline measurements were obtained after the
patient was placed under anesthesia. The patient
was anesthetized with general endotracheal anesthesia using isoflurane. No neuromuscular blockade was used, and measurements were obtained
every 2–3 minutes.
The distal third of the left clavicle was exposed
and morselized, preserving the periosteum. Posteriorly, an incision was made in the skin and trapezius in order to expose the superomedial border
of the left scapula. The trapezius and rhomboid
muscles were then dissected from their origins on
the spine, and an omovertebral bone arising from
the middle aspect of the medial border of the
scapula was removed. The superomedial border of
the scapula was excised in order to allow better
mobilization. The left scapula was translated caudally until the level of the spine of the scapula was
approximately equal to that of the contralateral
side. This was conformed by intraoperative radiographs. During this part of the procedure, the
SSEP monitoring of the brachial plexus remained
normal. Sutures were used to anchor the inferior
angle of the scapula to the nearest rib.
During closure of the soft tissues, approximately 10 minutes after anchoring of the scapula,
acute changes in amplitude and latency of the
somatosensory evoked potentials in the Cs2–Fpz
and Cs5–Fpz derivations from left ulnar stimulation were observed (Fig. 1). The latency in the
Cs2–Fpz derivations increased from 5.1 ms to 5.7
ms, and the amplitude decreased from 2.41 lV to
1.09 lV. In the Cs5–Fpz derivations, the latency
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February 2010
FIGURE 1. SSEP tracings. Stimulation was at the left or right ulnar nerve, and subcortical potentials were recorded. (A) SSEP tracings
at baseline, before manipulation of the deformity. (B) SSEP tracings immediately after correction of the deformity. (C) SSEP tracing 7
minutes after anchoring the deformity correction. There has been an interval decrease in the amplitude in the left Cs2–Fpz and Cs5–
Fpz signal. (D) SSEP tracing at 90 seconds after releasing the previous correction. Note the immediate return to baseline.
increased from 5.46 ms to 5.70 ms, and amplitude
decreased from 2.42 lV to 1.14 lV. There were no
changes in the somatosensory evoked potentials
from stimulation of the contralateral (right) side.
The patient’s temperature and blood pressure
remained stable throughout the procedure, and
blood loss to this point was estimated to be 50 ml.
These changes were observed for several minutes,
but there was no change in the somatosensory
evoked potentials. Thus, the left scapula was
released and allowed to move to the original, more
rostral position. The derivations from left ulnar
stimulation began to change within 30 seconds
and, by 90 seconds after release, the amplitude
and latency of the Cs2–Fpz and Cs5–Fpz derivations returned to baseline values.
Short Reports
The scapula was again moved caudally, although
to a lesser extent, and the spine of the scapula was
allowed to remain in a more rostral position compared with the contralateral (normal) side. Intraoperative radiographs demonstrated an improved
location of the scapula compared with the preoperative position, although the scapular spine was still
more rostral than the normal side (for radiographs,
see Supplementary Material). SSEP monitoring was
unremarkable throughout the remainder of the
procedure. Immediately postoperatively, the patient
had normal brachial plexus function.
At 2-year follow-up, the parents and patient
were pleased with the cosmetic result, brachial
plexus function was normal, cosmetic appearance
had improved, and shoulder mobility was
MUSCLE & NERVE
February 2010
263
increased. The patient was able to actively flex to
130 and passively to 160 . The patient was able to
actively abduct to 130 , passively to 160 . His external rotation was 70 on the affected shoulder, 75
on the contralateral. Internal rotation was to the
T6 level and symmetric bilaterally. Biceps, triceps,
forward flexion, and abduction were symmetric
and 5/5 in strength. Radiographs showed that the
correction of the deformity was stable.
DISCUSSION
Sprengel’s deformity is a rare congenital anomaly
of the shoulder girdle. Although the exact incidence is unknown, most major referral centers
treat only 1 or 2 cases per year.6,12 Correction of
Sprengel’s deformity is indicated for functional
and cosmetic reasons. A known complication of
caudalization of the scapula is brachial plexopathy
due to compression of the brachial plexus and subclavian artery between the clavicle and the first
rib.3–6 Clavicular osteotomy and/or morselization
may help to avoid this complication.7,8
SSEP monitoring is widely used for monitoring
spinal cord function during spine surgery and,
recently, it has been used to monitor brachial
plexus function. In this case, we used SSEP to
monitor brachial plexus function during a Woodward procedure. We were able to identify brachial
plexopathy during the procedure and were able to
appropriately modify the position of the scapula
and clavicle. There was no postoperative neurological injury, and the functional and cosmetic outcomes were excellent.
This case demonstrates the following: (1) even
with clavicular osteotomy and/or morselization,
brachial plexus injury is possible; (2) SSEP can be
successfully used to identify neuropraxia during the
Woodward procedure; and (3) changes in amplitude
and latency may occur in a delayed manner. In our
case, SSEP changes were not observed for nearly 40
minutes after initial manipulation of the deformity
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and 10 minutes after anchoring the correction.
Because of the ability to identify probable brachial
plexus injury, we recommend that SSEP be considered in procedures to correct Sprengel’s deformity,
including those with clavicular osteotomy or morselization. In this case report, limited monitoring via ulnar SSEPs was able to detect an impending brachial
plexus injury. For similar cases in the future, additional neuromonitoring, including EMG for neurotonic discharges, may also be considered. This may
provide earlier indication of nerve injury. In addition
to monitoring via the ulnar nerve, monitoring via the
median nerve should be considered, as this will provide feedback on more of the brachial plexus, any
part of which has the potential to be injured during a
Woodward procedure for Sprengel’s deformity.
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