LETTER TO THE EDITOR
Junctional neural tube defect: a supporting case report
P. Daniel McNeely
Received: 17 April 2018 / Accepted: 27 May 2018
Springer-Verlag GmbH Germany, part of Springer Nature 2018
After reviewing the literature and reading the article:
BUnjoined primary and secondary neural tubes: junctional
neural tube defect, a new form of spinal dysraphism caused
by disturbance of junctional neurulation^ by Eibach et al. ,
we believe to have encountered a clinical case of spinal
dysraphism that would fit this description. With only five
cases reported in the literature [1–3], we describe a sixth case
of a male patient that had clinical follow-up but no neurosur-
A 28-year-old male was followed since birth at the spina
bifida clinic for occult spinal dysraphism. Investigations were
completed secondary to a dimple in the lumbosacral junction
with no other visible spinal deformity. On magnetic reso-
nance, sacral agenesis was reported with an abruptly ending
spinal cord at the T12 level. An unrecognizable structure in
the lower sacrum was also described (Fig. 1).
Over the years, physical examination showed bilateral
lower extremity shortening and atrophy, as well as a
planovalgus deformity of the feet. Hypersensitivity was
described over the dorsal aspect of the great toes. Light
touch was generally intact in the lower extremities. Pain
symptoms were reported originating at the right great toe
and extending to the posterolateral buttock, right flank,
and anterior thigh regions.
Motor testing showed normal ankle dorsiflexion strength;
yet, a bilateral weakness in plantarflexion was observed. The
patient ambulated with a Trendelenburg gait pattern, without
requiring assistive devices. The patient had episodes of
incontinence. Urodynamic studies were recommended, but
the patient declined. On ultrasound, there was no significant
post void residual identified, there was no hydronephrosis,
and the kidneys were both normal.
The concept of junctional neurulation was first described
by Dady et al. as an embryological phenomenon that occurs at
the end of primary neurulation and before secondary neurula-
tion: relating the two processes spatially and temporally .
Eibach et al. further defined the clinical spinal dysraphism,
that appears to arise from this process, a junctional neural tube
defect . These authors described three cases of an 8, 25, and
30 year old, where two separate spinal cord segments ap-
peared to be functionally disjointed and physically separated,
yet only connected by a non-neural band of tissue on MR
imaging . It was proposed that the developmental error
was embryologically linked to the planar cell polarity path-
way, Prickle-1 gene, and associated absence of cell adhesion
molecules . The fourth case report was described by
Schmidt et al. of a neonate born at 38 weeks of gestation
. Florea et al. reported a fifth case alongside a lipoma of
the filum terminale in a 5-year-old boy .
Our patient presents with sacral agenesis and the distinct
separation of what appears to be two spinal cord segments.
The first segment ends at the level of T12, and the second
neural structure resembling spinal cord at the L4–L5 level.
Our patient’s clinical presentation is consistent with sacral
agenesis; however, we believe that his MRI imaging is highly
suspicious for a separate spinal cord segment, which could
represent another example of junctional dysraphism.
* Malik Ali
Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia,
Division of Neurosurgery, Dalhousie University, Halifax, Nova
Child's Nervous System