Keywords
double myelomeningocele - myelomeningocele - hydrocephalus - ventriculoperitoneal
shunt - neural tube defect
Introduction
Neural tube defects (NTDs) are among the most common congenital anomalies affecting
the central nervous system, with myelomeningocele (MMC) being the most severe form.[1]
[2] The mean incidence of MMC is 1 in 1,000 live births and among the 3,000 pregnancies
affected by NTD in the United States, 1,500 to 2,000 children are born with open MMC.[3]
[4] Spina bifida, a prominent example of NTDs, mostly manifests in two primary forms:
spina bifida occulta and the more severe spina bifida aperta.[5] These conditions frequently present alongside complications such as hydrocephalus
and varying degrees of motor impairment.[6] MMC, the most severe form of spina bifida, arises from the incomplete closure of
the neural tube during early embryonic life.[7] While single-level MMCs are relatively well-documented, instances of multiple-level
MMC are rare, with limited literature available on this specific presentation. There
are only approximately 60 documented cases of multiple NTDs.[5] This report details the case of a 4-month-old boy presenting with double MMC, with
the aim to better contribute to the understanding and management of this uncommon
condition.
Case Report
A 4-month-old male infant presented in the neurosurgery clinic with two congenital
swellings on his back since birth. Born via cesarean section at 36 weeks' gestation
to a 30-year-old mother (gravida 5 para 5), his birth weight was 2.9 kg, head circumference
was 34 cm, and length was 40 cm. The family's socioeconomic status was lower-middle
class, and the mother denied any history of substance abuse and had not received folic
acid or iron supplementation in the course of her pregnancy. Additionally, she had
not had any ultrasound imaging done during pregnancy and the pregnancy was otherwise
uncomplicated, with no maternal medical concerns reported. While there was a family
history of diabetes and hypertension, the mother reported no comorbidities of her
own and there was no prior family history of congenital anomalies.
The patient was admitted to the neurosurgery floor in a vitally stable state. Upon
examination, he appeared malnourished with two swellings on his back identifiable
at the lower cervical and lower lumbar levels, both in the midline. The upper swelling
appeared to be oval, with a smooth surface and being significantly smaller than the
lower swelling. The lower swelling was more irregular and bulbous, with a larger size
and dome-like appearance. Both swellings had a semitransparent skin covering, revealing
a reddish-pink hue with some areas appearing slightly more purple, indicative of underlying
vascular tissues. Both swellings exhibited transillumination when light was shown
across them, suggesting the swellings were fluid-filled. There was no active leakage
noted from either swelling ([Fig. 1]).
Fig. 1 Preoperative image of patient showing the two myelomeningoceles.
Suspecting spina bifida aperta, a neurological examination was done to check for muscular
tone, reflexes, power, and range of motion and scoring was done according to spina
bifida neurological scale. Deep tendon reflexes were all present and muscle tone was
normal. Movements including flexion, extension, abduction, and adduction in the hip,
knee, ankle, and neck were normal for a 4-month-old baby; however, there were diminished
reflexes with weakness and decreased movements in the left lower limb. History was
unremarkable for any difficulty in passing urine or stool.
Magnetic resonance imaging (MRI) of the entire spine revealed MMCs at the C5-D1 and
D8-lower lumbar levels ([Fig. 2]). Herniation of cerebrospinal fluid (CSF) and neural contents was appreciated in
both the MMCs. The spinal cord was tethered anteriorly with widened posterior epidural
space. MRI of the brain showed hydrocephalus, significant herniation of brainstem
and cerebellar tonsils with syrinx formation, tectal beaking, and dilated lateral
ventricles; findings which were conclusive of Arnold–Chiari malformation.
Fig. 2 Sagittal and axial magnetic resonance imaging (MRI) scan showing double myelomeningoceles
and their contents.
A cerebral computed tomography (CT) scan was done, which also revealed dilated ventricles
and hydrocephalus ([Fig. 3]). Echocardiography was performed to check for congenital heart disease, atrial septum
defect, ventricular septum defect, or tetralogy of Fallot, often associated with NTDs,[8] but no such abnormality was noticed in the report. Laboratory investigations were
conducted, and they were within normal limits.
Fig. 3 Preoperative axial brain computed tomography (CT) scan of the patient showing hydrocephalus.
The patient developed pneumonia after admission. Given his malnourished state, a clinical
decision was made to manage the acute infection before embarking on the surgical correction
of the patient's neurological deformities. After 1 week of intravenous antibiotics
the patient recovered from the pneumonia but there was a delay in operation of further
3 weeks due to high patient influx in the government hospital setup. The surgical
procedure was then performed which included insertion of ventriculoperitoneal (VP)
shunt and double MMC repair.
The procedure started with the insertion of VP shunt in the supine position. A horseshoe-shaped
incision was given on the right keen's point, and after raising the scalp flap, a
single burr hole was made. The second incision was made two fingers-widths below the
right subcostal margin. Using a VP shunt passer, a pathway was established from the
abdominal incision to the cranial incision in the subcutaneous plane and after stabilization,
VP shunt was threaded along this path. Dura was incised and the upper end of the VP
shunt was carefully inserted into the ventricle at a 90-degree angle directed toward
the ipsilateral medial canthus. The shunt contacted the ventricle at 3-cm depth, where
a high flow of clear CSF was observed. A total of 8 cm segment of catheter was placed
inside and fixed through 2.0 silk sutures. The lower end of the shunt was then placed
inside the peritoneal cavity after opening layer by layer and then closing in the
same fashion. The abdominal skin and scalp were closed, and the patient was shifted
to a prone position for MMC repair. An elliptical incision was given around the lower
cervical MMC, and the subcutaneous plane was dissected. The exposed dura was found
to be torn, revealing nerve roots and meningeal layers extruding from the spinal canal.
The nerve roots were carefully separated and preserved. The tethered cord was identified
and detethering of the cord was done. All the contents were placed back into the canal
and the dura was closed in a watertight fashion with 3.0 Vicryl sutures. Hemostasis
was secured, and the muscles, fascia, and skin closure were done layer-by-layer. The
same procedure was performed for lower lumbar MMC.
The patient responded well to the surgery and no new postoperative deficits were noted.
He was shifted to the intensive care unit for a 2-day postoperative observation period
before being discharged. Postoperative CT scan was negative for hydrocephalus. The
nonabsorbable stitches were removed after 2 weeks and a follow-up was conducted 1
month postsurgery; the patient's neurological status was similar to that observed
before the procedure. Subsequent follow-ups showed improvement in power and lower
limb movements and the follow-up period is now more than 10 months. Currently, the
patient is showing good progress and is meeting all age-appropriate milestones including
crawling, with satisfactory healing of surgical scars ([Fig. 4]).
Fig. 4 Postoperative image of patient showing corrected spinal defect and healing wounds.
Discussion
MMC is the most common NTD and can have multiple etiologies such as folate deficiency.
Environmental factors including socioeconomic status, education, and culture are also
implicated in altering the likelihood of developing MMC.[5] This congenital malformation is associated with a spectrum of clinical manifestations
including motor and sensory deficits, bowel and bladder dysfunction, hydrocephalus,
and cognitive disabilities.[9] Double MMC has very rarely been reported in the literature, with only a few case
reports available from some parts of the world and none from Southeast Asia.[10]
Morphologically, the closure of the neural tube during development is explained by
the zipper model in which the neural folds in apposition close bidirectionally from
a single starting point toward the cranial and caudal ends in a zipper-like fashion.[11] However, closure from a single point fails to satisfy the possibilities of multiple
NTDs, leaving the exact pathophysiology of double MMCs uncertain. Instead, Van Allen's
hypothesis offers a better understanding of this phenomenon. He presented through
experiments that there exist about five or more distinct sites of closure, including
mid-cervical region, junction between prosencephalon and mesencephalon, stomodeum,
caudal end of rhombencephalon, and lastly, the most caudal end.[12] His multisite closure hypothesis, where two separate sites of closure can fail to
close fully, explains the formation of MMC at two separate locations.
While surgical repair remains the mainstay of treatment for MMCs, postoperative care
holds immense importance in ensuring the longevity of its desired outcomes.[6] Moreover, inadequate surgical technique increases the chances of needing redo surgery
to correct the defect and also increases the chances of worsening of complications
for MMC, including on occasions when redo surgeries were performed for tethered cord
following meningocele repair, complications such as dermoid and epidermoid cysts were
observed, often linked to inadequate excision of cutaneous elements and implantation
at the repair site. Additionally, hamartomatous lesions are a common feature of the
myelodysplastic sequence.[13] Other complications such as wound dehiscence, abscess formation, and infections
are one of the leading incidences of inadequate postop care.[2] Therefore, prolonged hospital admission and proper nursing care are important variables
for proper care and fast recovery postoperatively.
A significant majority of women in developing countries like Pakistan lack knowledge
about prenatal care, NTDs, and the importance of folic acid in reducing the risk of
NTDs. Therefore, there is a pressing need for awareness through comprehensive health
care campaigns to prevent such congenital anomalies.[14] On the other hand, surgical repair right after birth or during the first few weeks
leads to better prognosis, quick recovery, and better cognitive development.[15] However, in our case, the same results were achieved even though the repair was
done after 4 months, and no postoperative complication has been reported yet by the
patient's attendants.
Conclusion
MMC is caused by a combination of different factors of which folic acid deficiency
undoubtedly seems to be the most common and prevalent, especially in low socioeconomic
countries where the nutrient deficient diet among women needs to be supplemented with
folic acid.[16]
[17] In this case, folic acid supplementation was overlooked which may have contributed
to the development of MMC. Hence, it is crucial to raise awareness about the importance
of antenatal care and folic acid's role in decreasing NTDs in third world countries.[16] Similarly, early surgical intervention in such neurological deformities is also
essential for better prognosis.
