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ORIGINAL PAPER
Neurosurgical management of occult spinal dysraphism
associated with OEIS complex
Takato Morioka & Kimiaki Hashiguchi &
Fumiaki Yoshida & Kenichi Matsumoto &
Yasushi Miyagi & Shinji Nagata & Takashi Yoshiura &
Kouji Masumoto & Tomoaki Taguchi & Tomio Sasaki
Received: 7 August 2007 / Published online: 26 October 2007
#
Springer-Verlag 2007
Abstract
Introduction OEIS complex has been described as a
combination of defects consisting of omphalocele (O),
exstrophy of the cloaca (E), imperforate anus (I), and spinal
defects (S). As the first three defects are life-threatening and
treated on a priority basis, neurosurgical intervention for
spinal defects is deferred until recuperation from abdomi-
nogenital repair. However, the best timing for neurosurgical
operation has not been precisely descri bed.
Materials and methods We reviewed our neurosurgical
management of three cases (case 1: myelomeningocele;
cases 2 and 3: terminal myelocystocele). At 2–6 (3.6 on
average) months after birth, neurosurgical procedures,
including reduction of the size of the lumbosacral cystic
lesion and untethering of the spinal cord, were perfor med.
Results During this period, the patients’ weights increased
from 1,911 to 3,368 g on average, and the lumbosacr al
cystic lesion was markedly enlarged. In all cases, no
neurological deterioration was seen, and ventriculoperito-
neal shunt was not indicated.
Conclusion Thus, neurosurgical procedures can be per-
formed in patients weighing 3–4 kg and/or at an age of
3 months, after confirming recuperated conditions from
abdominogenital repair. Care ful observation should be
made of the size of the lumbosacr al cystic lesion and
neurological deterioration.
Keywords OEIS complex
.
Terminal myelocystocele
.
Occult spinal dysraphism
Introduction
OEIS complex was described by Carey et al. [3]asa
combination of defects consisting of omphalocele (O),
exstrophy of the cloaca (E), imperforate anus (I), and spinal
defects (S). The incidence is not known, as many affected
pregnancies are terminated [1, 12]. Omphalocele, exstrophy
of the cloaca, and imperforate anus are life-threatening and
are treated by pediatric surgeons on a priority basis. By
contrast, the most common pathol ogical condition of spinal
deformity associated with OEIS complex is occult spinal
dysraphism, such as terminal myelocystocele, a deformity
that is covered with normal skin, and neurosurgical
intervention is deferred until recuperation from abdomino-
genital repair [4, 5, 13, 16]. However, the best timing for
neurosurgical operation has not been precisely described.
Thus, we reviewed the clinical and neuroradiological
findings of three cases with OEIS complex from a neu-
rosurgical point of view.
Childs Nerv Syst (2008) 24:723–729
DOI 10.1007/s00381-007-0519-y
T. Morioka (*)
:
K. Hashiguchi
:
F. Yoshida
:
K. Matsumoto
:
Y. Miyagi
:
S. Nagata
:
T. Sasaki
Department of Neurosurgery,
Graduate School of Medical Sciences, Kyushu University,
3-1-1 Maidashi, Higashi-ku,
Fukuoka 812-8582, Japan
e-mail: takato@ns.med.kyushu-u.ac.jp
T. Yoshiura
Department of Clinical Radiology,
Graduate School of Medical Sciences, Kyushu University,
Fukuoka 812-8582, Japan
K. Masumoto
:
T. Taguchi
Department of Pediatric Surgery,
Graduate School of Medical Sciences, Kyushu University,
Fukuoka 812-8582, Japan
Y. Miyagi
Division of Digital Patient, Digital Medicine Initiative,
Kyushu University,
Fukuoka 812-8582, Japan
Materials and methods
From 1995 to 2006, three patients with OEIS complex were
treated at our university hospital. All patients were female.
Clinical, neuroradiological, and operative findings, as well
as long-term outcomes, were reviewed retrospectively.
Results
All patients were diagnosed as having abdominal-wall
defects with omphalocele and spinal dysraphism by trans-
abdominal ultrasound (US) examination at 27–31 weeks of
gestation (Table 1). Case 3 also underwent prenatal
magnetic resonance imag ing (MRI) at 30 weeks and 3 days
of pregnancy, as described previously [6, 14], revealing an
abdominal-wall defect with omphalocele (Fig. 1a) and a
meningocele sac (Fig. 1b). Furthermore, prenatal MRI clearly
demonstrated that neither Chiari malformation nor hydro-
cephalus was present (Fig. 1b).Cases2and3underwent
perinatal management at the perinatal and maternity care unit
of our hospital, and case 1 received care at a related hospital.
In all cases, elective cesarean (C-) section was sched-
uled; however, emergency C-section was performed at
37 weeks 1 day, 33 weeks 4 days, and 36 weeks owing to
the pelvic position of the fetus, fetal distress, and premature
rupture of the membrane in cases 1, 2, and 3, respectively.
Body weight at birth was 1,900, 1,520, and 2,314 g in cases
1, 2, and 3, respectively (1,911 g on average). Apgar scores
were 7/8, 2/9, and 6/8 in cases 1, 2, and 3, respectively. At
birth, typical findings of omphalocele (Fig. 1c), exstrophy
of the cloaca (Fig. 1c), and imperforate anus (Fig. 1d) were
obtained. Small subcutaneous masses (5–6×3×3 cm in
length, wi dth, and thickness) covered with normal skin
were noted in the lumbosacral region (Fig. 1d). Positive
neurological findings of all cases were paraparesis with
deformity of legs. On 5 days after birth in case 1 and 0 day
in cases 2 and 3, primary or gradual closure of the abdominal
wall, closure of the urinary bladder, and ileostomy were
performed by pediatric surgeons.
Neurosurgical operations were performed at 2 months,
3 months, and 6 months (3.6 months on average) after birth,
respectively. Body weights at the time of neurosurgical
operation were 3,100, 2,505, and 4,500 g (3,368 g on
average) in cases 1, 2, and 3, respectively. During the
period before neurosurgery, the lumbosacral masses of all
patients gradually and markedly increased in size (to 16–
23×7–17×9 cm; Fig. 2a–c). However, no neurological
deterioration was present.
In case 1, preoperative MRI revealed a low-lying cord
and cystic dilatation of the terminal spinal cord, which was
surrounded by a huge subarachnoid space (Fig. 2d). At
surgery, opening of the small second cyst revealed a neural
placode anchoring the inner wall of the cyst (Fig. 2c).
Operative diagnosis was myelomeningocele instead of
terminal myelocystocele. The neural placode was unteth-
ered from the cyst wall (Fig. 2j).
In case 2, preoperative MRI also revealed a low-set
conus medullaris with a distal cystic dilatation, which was
surrounded by a huge subarachnoid space (Fig. 2e). Opening
Table 1 Clinical profile of the patients with OEIS complex
Case 1 Case 2 Case 3
At birth
Gestation 37 weeks 1 day 33 weeks 4 days 36 weeks
Delivery Emergency C-section
(pelvic position)
Emergency C-section
(fetal distress)
Emergency C-section
(PROM)
Body weight 1,900 g 1,520 g 2,314 g
Apgar score 7/8 2/9 6/8
Lumbosacral mass size
(length×width×thickness)
5×3×3 cm 6×3×3 cm 5×3×3 cm
Pediatric surgery 5 days 0 day 0 day
At neurosurgery
Age 2 months 3 months 6 months
Body weight 3,100 g 2,505 g 4,500 g
Lumbosacral mass size 16×7×9 cm 23×17×9 cm 16×7×9 cm
Diagnosis Myelomeningocele Terminal myelocystocele Terminal myelocytocele
At present
Age 12 years 8 years 1 year
Neurology Paraparesis Paraparesis Paraparesis
Chiari malformation + −−
VP shunt −− −
C-section Caesarean section; PROM premature rupture of membrane
724 Childs Nerv Syst (2008) 24:723–729
of the small second cyst revealed a dilated terminal central
canal that communicated with the rostral central canal, a
typical finding in cases of terminal myelocystocele (Fig. 2h).
A neural placode was untethered from the wall of the cyst
(Fig. 2k), and the central canal was opened to the sub-
arachnoid space.
In case 3, preoperative MRI also revealed cystic
dilatation of the terminal spinal cord, which communicated
with the rostral hydromyelia (Fig. 2f). The lumbosacral
mass had two cystic components. Three-dimensional (3-D)
constructive interference in steady-state (CISS) imaging
was performed, as described previously [8, 9, 15, 18].
Serial sections of a thin-sliced reconstructed sagittal view of
3-D CISS images clearly showed the terminal myelocysto-
cele forming a caudal (main) cyst and rostal hydrom yelia
forming a rostral cyst (Fig. 3a). The two cystic lesions were
divided by a soft-tissue band. Although coronal CISS images
failed to reveal t his complicated pathology (Fig. 3b),
Fig. 1 Case 3. a, b Sagi ttal
view of a heavily T2-weighted
image (T2WI) with half-Fourier
acquisition single-shot turbo spin-
echo (HASTE) sequences at
30 weeks and 3 days of gestation
showing the abdominal-wall de-
fect with omphalocele (a, arrows)
and occult spinal dysraphism (b,
arrows). Neither Chiari malfor-
mation nor hydrocephalus is
noted. c, d Photograph at birth.
Typical findings of omphalocele
(c, white arrows), exstrophy of
the cloaca (c, black arrows) and
imperforate anus (d, white ar-
row) are seen. A small mass
covered with normal skin is
noted at the lumbosacral region
(d, black arrow)
Childs Nerv Syst (2008) 24:723–729 725
curvilinear reconstruction of CISS sequences, reconstructed
according to the curved planes of the spinal cord, clearly
showed the topographical relationship between the two
cysts (two com ponents of the syringocele; Fig. 3c).
Opening of the cyst revealed an open central canal that
communicated with the rostral central canal (Fig. 2i). The
neural placode was untethered from the wall of the cyst,
and the central canal was opened to the subarachnoid space
(Fig. 2l). A fibromuscular band divided the two compo-
nents of the cyst.
Fig. 2 a, b, c Photograph of case 1 at 2 months, case 2 at 3 months,
and case 3 at 6 months, respectively. Note the giant lumbosacral mass,
which markedly increased in size (compare Fig. 2c with Fig. 1d). d, e, f
Preoperative sagittal view of conventional T2WI of cases 1, 2, and 3,
respectively. In cases 1 and 2, MRI reveals a low-lying spinal cord and a
cystic dilatation of the terminal cord, which is surrounded by a huge
subarachnoid space (d, e). In case 3, MRI also demonstrates a low-set
conus medullaris with cystic dilatation of the terminal cord, which is
connected to rostral hydromyelia (f). g, h, i Intraoperative photograph
after opening of the cystic lesions of cases 1, 2, and 3, respectively.
(Rostral to the viewer’stop) j, k, l Intraoperative photograph after
untethering of the spinal cord of cases 1, 2 and 3, respectively. In case 1,
opening of the small cyst reveals a neural placode (g, white arrows)
anchoring the inner wall of the cyst, and myelomeningocele instead of
terminal myelocystocele is diagnosed. The neural placode is untethered
(j). In case 2, opening of the cyst reveals a dilated central canal that
communicates with the rostral central canal (h, white arrow). The neural
placode is untethered from the wall of the cyst, and the central canal is
opened to the subarachnoid space (k). In case 3, opening of the cyst
reveals a dilated central canal that communicates with the rostral central
canal (i). The neural placode is untethered from the wall of the cyst, and
the central canal i s opened to the subarachnoid space (l). A
fibromuscular band, which divides the two components of the cyst, is
observed
726 Childs Nerv Syst (2008) 24:723–729
As there was no ventricular enlargement in all cases, a
ventriculoperitoneal (VP) shunt was not indicated. Postop-
erative MRI confirmed the successful untethering of the
spinal cord. Syringomyelia was absent. Only case 1 had
Chiari malformation. At the 1–12 year follow-up, intellec-
tual development was shown to be normal in these patients;
however, there was no improvement in paraparesis. Cases 1
and 2 go to an ordinary junior high school and elementary
school, respectively, with the use of wheelchairs, and their
school marks are close to average.
Discussion
The striking coexistence of occult spinal dysraphism, such
as terminal myelocystocele, with cloacal exstrophy, as seen
in OEIS complex, is well known [2, 5 ]. Cohen [5] suggests
that the entire spectrum of abnormalities in both cloacal
exstrophy and occult spinal dysraphism can be explained
by a single defect in the developing embryonic tail. The
coexistence of these de fects can be explained by the
proximity of the neural tube to the cloaca in the developing
embryo. A single insult to the primitive streak after closure
of the posterior neuropo re during the second month of
development can explain the pathogenesis of both cloacal
exstrophy and spinal dysraphism [5, 12]. Another notable
complex, which is complicated with occult spinal dysra-
phism, is VATER syndrome (for the nonrandom association
of vertebral abnormality, anal imperforation, tracheoeso-
phageal fistula, and renal-radial abnormalities) [4, 16]. We
have not experienced cases of VATER syndrome.
Terminal myelocystoceles are the most common spinal
dysraphism in patients with OEIS complex, although they
can occur independently of cloacal exstrophy [7, 10]. Choi
and McComb [4] reported a large series of cases of terminal
myelocystocele, in which seven out of nine cases had OEIS
complex. In Pang’s[16] series, three of the four cases of
OEIS complex had a spinal cord ending in a terminal
myelocystocele, and the fourth case had a spinal lipoma of
transitional type. In the present study, two cases (cases 2
and 3) had terminal myelocystocele, and one had myelo-
meningocele.
To detect OEIS complex prenatally, fetal US examina-
tion remains the most noninvasive and best tool [1]. The
main prenatal US findings are ventral-wall defects with
omphalocele, skin-covered lumbosacral neural tube defects,
Fig. 3 Case 3. a Serial sections
of a thin-sliced reconstructed
sagittal view of three-dimensional
constructive interference in
steady-state (CISS) images
clearly demonstrate the terminal
myelocystocele and rostal
hydromyelia forming a rostral
cystic lesion. The two cystic
lesions are divided by a soft
tissue band. b Coronal CISS
images fail to reveal the com-
plicated pathology. c Curvilinear
reconstruction of CISS se-
quence, reconstructed according
to the curved planes of the
spinal cord, clearly demonstrates
the topographical relationship
between two cystic lesions
(syringoceles)
Childs Nerv Syst (2008) 24:723–729 727
and nonvisualized bladder; however, prenatal US examina-
tion fails to demonstrate the abdominal genitalia, bladder
exstrophy, and anal atresia [1]. With detailed US examina-
tion, prenatal diagnosis can be made as early as 16 weeks of
gestation [1]. In this study, all patients were diagnosed as
having omphalocele and spina bifida by routine trans-
abdominal US examination at 27–31 weeks of gestation.
In addition to US, information provided by prenatal MRI
permits a better understanding of the m orphological
abnormalities of the fetus [6, 14]. In particular, the half-
Fourier acquisition single-shot turbo spin-echo (HASTE)
sequence, in which high-resolution heavily T2-weighted
images can be obtained in a reasonable time [19], provides
diagnostic images of the fetus [6, 14]. However, as far as
we know, there is no previous report regarding MRI in
fetuses with OEIS complex. In our case 3, HASTE MRI at
30 weeks and 3 days of gestation clearly demonstrated a
ventral-wall defect with omphalocele and a skin-covered
lumbosacral neural tube defect. Neither Chiari malforma-
tion nor hydrocephalus was present. However, it is difficult
to demonstrate abdominal genitalia, bladder exstrophy, and
anal atresia, as it is by US examination. Furthermore, the
type of spinal dysraphism could not be elucidated.
After birth, conventional MRI has been the inves tigation
of choice for the diagnosis of occult spina dysraphism, and
terminal myelocystocele typically shows a dilated ventric-
ulus terminalis with a trumpet-like flare [ 2, 7, 17]. In the
present study, preoperative diagnosis with conventional
MRI of all our patients was terminal myelocytocele;
however, operative findings reveale d that c ase 1 ha d
myelomeningocele instead of terminal myelocystocele. A
possible main reason for this misdiagnosis is that conven-
tional MRI provides sections that are 2–5 mm thick, a
thickness that is insufficient for detailed imaging of the
neural placode or nerves in neonates and infants [8, 9, 15].
In our previous studies, we reported on the usefulness of
3-D CISS sequence for diagnosing spinal dysraphism
[8, 9, 15]. It is possible to reconstruct 3-D CISS images
with a minimum slice thickness of 0.2–0.3 mm in any
specified linear or curved plane [8, 9, 15 ,18].
Case 3 had two cystic components in the lumbosacr al
mass, and serial sagittal sections and curvilinear reformat of
3-D CIS S clearly demonstrated that both cystic components
were serial syringoceles, which were divided by a fibro-
muscular band. Although conventional MRI is an excellent
screening test for spinal dysraphism associated with OEIS
complex, the details of spinal dysraphism can be further
delineated by 3-D CISS ima ges, which can also serve as a
surgical road map.
The main goal of neurosurgical intervention is to reduce
the size of the mass and to untether the spinal cord,
although these patients have no chance of bowel or bladder
control [4, 7]. In our cases, successful untethering of the
spinal cord was performed, and neurological deterioration
was not seen during long-term follow-up. Once the placode
is untethered, previous authors [4, 7] have stated that the
conus should be reconstructed with interrupted pia-arachnoidal
sutures to reduce the surface area available for scarring and
subsequent retethering. However , it is postulated that the
caudal part of the central canal should be opened to the
subarachnoid space (terminal ventriculostomy), as the terminal
myelocystocele is hydromyelic caudal spinal cord. To close the
central canal may cause subsequent hydromyelia in the rostral
spinal cord.
It is clear that neurosurgical treatment for occult spinal
dysraphism should usually be undertaken after the infant
recovers from the initial series of major abdominopelvic
procedures, as omphalocele, exstrophy of the cloaca, and
imperforate anus are life-threatening [5, 16]. However,
there are no established guidelines regarding the optimal
timing of neurosurgery. Although Choi and McComb [ 4 ]
documented that neurosurgical correction of the myelocys-
tocele in seven patients associated with OEIS complex was
undertaken between the ages of 1 and 19 months, with a
mean of 5 months, there was no theoretical basis regarding
the timing of neurosurgery.
One of the possible reasons why the neurosurgical
procedure would be deferred is low body weight of the
baby with serious anomalies. Although there is no precise
description of the body weight at birth of babies with OEIS
complex, the body weight of our babies was as low as
1,911 g on average. At our institute, when lumbosacral
lipoma with intact or subtle neurologic al findings is
diagnosed at birth, surgery is postponed until a baby
reaches a weight of 5 kg and/or an age of 3 months [15].
Another reason for delaying neurosurgery is that a VP
shunt may be necessary after the resection of the myelo-
meningocele or myelocystocele sac. As seen in our series, a
previous study revealed that pati ents with occult spinal
dysraphism have a low incidence of intracranial abnormal-
ities associated with opened spinal dysraphism, such as
Chiari malformation and hydrocephalus [11]. However,
Choi and McComb [4] demonstrated that one out of seven
patients with OEIS complex required a VP shunt for
progressive hydrocephalus. Gupta and Mahapatra [7] also
stated that hydrocephalus was seen in one case with
associated aqueductal stenosis out of 17 cases with terminal
myelocystocele (not associated with OEIS complex). As the
necessity of a VP shunt can not be completely excluded,
neurosurgical procedures are deferred until complete
recovery from abdominogenital problems is achieved.
However, all patients presented with progressively
increasing lumbosacral cystic masses [4, 7]. In all our
patients, the lumbosacral cystic lesion also slowly and
markedly grew from 5–6×3×3 cm to 16–23×7–17×9 cm in
length, width, and thickness, during the postnatal 2–6months.
728 Childs Nerv Syst (2008) 24:723–729
It is postulated that increased body weight (averaged 1,457 g)
is mostly attributed to increased cerebrospinal fluid in the
cyst, as it is hard for patients with intestinal problems, such as
ileostomy, to gain weight. A more important indication of
neurosurgery is neurological deterioration [4], as the clinical
manifestation of occult spinal dysraphism is probably due to
worsening of the tethering effect [16]. Case 2 of McLone and
Naidich’s[13] series underwent repair of terminal myelo-
cystocele at 15 weeks of age because of deterioration of
paraparesis. However, in our patients, no neurological
deterioration was seen. Thus, neurosurgical procedures can
be performed in patients weighing 3–4kgand/oratanage
of 3 months, after confirming recuperated conditions from
abdominogenital repair. Careful observation should be made
of the size of the lumbosacral cystic lesion and neurological
deterioration.
Acknowledgment We thank Mikiko Hidaka for her valuable
assistance in preparing the manuscript.
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