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Original Article
Surgical Correction of Spinopelvic
Instability in Children With Caudal
Regression Syndrome
Sergei Vissarionov, MD
1,*
, Josh E. Schroder, MD
2,*
, Dmitrii Kokushin, MD
1
,
Vladislav Murashko, MD
1
, Sergei Belianchikov, MD, PhD
1
, and Leon Kaplan, MD
2
Abstract
Study Design: Retrospective cohort.
Objective: To analyze the outcome of surgical correction of children with caudal regression syndrome.
Methods: The study included 12 patients aged 1.5 to 9 years with caudal regression syndrome. In order determine the type of
caudal regression, the Renshaw Classification was used. The surgery included correction and stabilization of the kyphotic
deformity at the unstable lumbosacral region, with reconstruction of the sagittal balance using a bony block constructed from
allograft. Short- and long-term outcomes were evaluated. The study was approved by the local institutional review board.
Results: Children with types III and IV caudal regression syndrome underwent spinal-pelvic fusion, with 100% fusion rate, which
allows sufficient stabilization of the lumbopelvic segment permitting patient mobilization and standing in type III patients. There
were 5 complications needing additional care.
Conclusion: Multilevel pedicular screw fixation in combination with spinopelvic fusion with cortical allografts allows recon-
struction of the sagittal alignment with solid bony fusion improving the quality of life for these patients.
Keywords
caudal regression syndrome, sacral agenesis, lumbosacral agenesis, spinopelvic instability, surgical treatment, children
Introduction
Caudal regression syndrome is a rare congenital malforma-
tion of the spine and caudal spinal cord combined with a
pathology of the visceral organs and lower extremities.
According to the clinical and neuroradiological classification
of Tortori-Donati et al,
1
caudal regression syndrome pertains
to a group of closed forms of spinal dysraphism without
subcutaneous mass. In the context of embryogenesis, this
defect is a result of a failure of notochord formation occur-
ring at the stage of gastrulation.
2,3
Renshaw et al
4
divide the condition into 4 groups (Figure 1):
type I is defined as a partial or total unilateral sacral agenesis.
Type II has a partial sacral agenesis with a bilateral symme-
trical defect, a normal or hypoplastic sacral vertebra, and an
articulation between the ilia and the first sacral vertebra. In type
III, there is a variable lumbar and total sacral agenesis, with the
ilia articulating with the sides of the lowest vertebra present;
and in type IV, a variable lumbar and total sacral agenesis exist,
with the caudal endplate of the lowest vertebra resting above
either fused ilia or an iliac amphiarthrosis.
Recently, a number of studies focusing on the surgical
treatment of children with caudal regression syndrome were
presented.
5,6
The existing literature on the treatment of
patients with this pathology considers the results of the
surgical treatment of individual cases with short-duration
follow-up.
5-15
1
The Turner Research Institute for Children’s Orthopedics, St. Petersburg,
Russia
2
Hadassah Hebrew University Medical Center, Jerusalem, Israel
* These authors contributed equally to this work.
Corresponding Author:
Vissarionov Sergei, The Turner Scientific and Research Institute for Children’s
Orthopedics, Parkovaya St, 64-68, Pushkin, Saint Petersburg 196603, Russia.
Email: VissarionovS@gmail.com
Global Spine Journal
1-6
ªThe Author(s) 2018
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The objective of this article is to analyze the long-term
results of surgical treatment of spinopelvic instability in chil-
dren with caudal regression syndrome.
Materials and Methods
Twelve patients (8 boys and 4 girls) with caudal regression
syndrome were surgically corrected and retrospectively
reviewed in the study (Table 1). Surgeries were performed
between 2008 and 2014 at a single referral center.
Clinical and radiological examinations (spine and pelvis X-
rays, computed tomography [CT] scans, and magnetic reso-
nance imaging (MRI) examinations of the cervical, thoracic,
and lumbar spine) were reviewed.
Patient pathology was described according to the Renshaw
Classification (Figure 1), which divides patients’ pathology
according to the level of spinopelvic segment instability and
aims to assist in treatment planning between conservative and
surgical treatment of patients with this pathology.
4
Neurological examination of the patients is aimed to detect
any motor and sensory disorders that may vary from deformity
to deformity. The pediatric physical examination evaluates the
nature of pathological changes in visceral organs associated
with the deformity of spinopelvic segment and concurrent
conditions.
16
Spine and pelvis X-rays are performed in 2 standard projec-
tions in the supine position. Kyphosis was measured through
the Cobb angle formed by the intersection of 2 lines: one pass-
ing through the posterior surface of the lowest remaining ver-
tebrae and other through the anterior surface of the pelvis ilium
(Figure 2).
Anatomical and anthropometric features of bony struc-
tures of the deformed vertebrae and pelvic complex were
assessed according to CT findings. The type of caudal
regression, size and shape of caudal vertebral bodies, and
spatial position of the pelvis were specified, and preopera-
tive planning was done with the choice of optimal instru-
mentation design and the number and sizes of anchoring
elements (Figure 3).
Intracanal pathology and the condition of the spinal cord and
its components were identified on the spine MRI scans, which
Figure 1. Renshaw sacral agenesis classification. (A) type I; (B) type II; (C) type III; (D) type IV.
Table 1. Vertebral Level of the Caudal Regression.
Renshaw
Type of
Regression T9 T10 T11 T12 L1 L2 L3 L4 L5 S1 S2 Total
Type III — — — — — — — 4 1 — — 5
Type IV 1 — 1 1 1 1 1 1 — — — 7
2Global Spine Journal
allowed assessing the location and nature of changes in the
spinal cord and detecting the level of medullary regression.
Based on the results of spine CT and MRI, the affected
vertebral and conus medullaris levels were determined in
patients with caudal regression syndrome (Tables 1 and 2).
Children were examined before surgery, immediately after
surgery, and at 6, 12, and 18 months after surgical treatment,
and thereafter once a year. Postoperative follow-up period ran-
ged from 2 to 7 years (see Figure 4).
Surgical Approach (Figure 5)
Surgical approach in all patients included a corrective osteot-
omy of the kyphotic deformity of the spine combined with an S
fixation in order to eliminate the instability. This was per-
formed with a posterior based spinopelvic fusion restoring the
physiological sagittal profile. The newly generated support for
the spine is based on the rods with the placement of split cor-
tical allografts along the spinal implants allowing solid bony
fusion (Figure 5C). Pedicle screws or laminar hooks were
inserted into vertebral bodies of the caudal segments of the
spine and the pelvis. The selection of the instrumentation
inserted into the caudal spine segments was dependent on the
anatomical features of vertebral bodies. The instrumentation
used to stabilize the pelvis was based on the thickness of cor-
tical plates and iliac spongy tissue as determined by CT
measurement.
Figure 2. Method for measuring the magnitude of kyphotic deformity of spinopelvic segment in children with caudal regression syndrome.
Figure 3. Admission spine and pelvis computed tomography scans in patients with caudal regression syndrome on admission: (a) Patient E, 2-
year-old child with type III caudal regression syndrome; (b) Patient S, 1.5-year-old child with type IV caudal regression syndrome.
Table 2. Medullary Level of the Caudal Regression.
Renshaw Type
of Regression T8 T9 T10 T11 T12 T13 L1 L2 Total
Type III — — 1 — 2 1 — 1 5
Type IV 1 3 1 1 1 — — — 7
Vissarionov et al 3
Patients with type III caudal regression were mobilized at
the 3rd to 10th days after surgery into a rigid brace. Patients
with type IV were protected with custom-made rigid braces
with a pantaloon extension allowing sitting. Patients were dis-
charged after surgery to outpatient treatment at the 17th to 21st
days after surgery.
The postoperative rehabilitation program included respira-
tory exercises, massage of lower and upper extremities, and
restoration exercises such as balanced sitting, standing, and
ambulation with the braces.
Results
Twelve children were included in the study. The age of chil-
dren operated ranged between 1.5 and 3 years, and only one
child was 9 years old.
Clinical and Neurological Status
Clinical presentation of the disease included kyphosis at the
level of the spinopelvic segment in all patients. The thorax was
barrel-shaped. No scoliosis was present. Five of the 7 children
having Renshaw type IV caudal regression suffered from skin
thinning with hyperemia over the apex of kyphosis due to the
pressure caused by caudal part of the spine. All patients had
shallow intergluteal cleft and hypoplasia of the sacrum and
gluteal region.
Concerning the associated pathology in the lower extremi-
ties, 4 patients with type III caudal regression had bilateral hip
dislocations. Bilateral paralytic clubfeet and leg muscle hypo-
trophy was observed in all cases of type III lumbosacral agen-
esis. Patients with this type of caudal regression retained the
ability to stay upright with a support but could not move
independently.
Figure 4. Long-term follow-up spine and pelvis computed tomography scans in patients with caudal regression syndrome: (a) Patient E, 6-year-
old child with type III caudal regression syndrome, 4 years after surgery; (b) Patient S, 5-year-old child with type IV caudal regression syndrome,
3.5 years after surgery.
Figure 5. Clinical pictures of a sacral agenesis case: (A) top and (B) side views prior to fixation. (C) After implant placement and bone graft
placement.
4Global Spine Journal
Patients with type IV caudal regression had flexion-
abduction contractures of the hip, flexion contractures of the
knee with severe skin pterygia of popliteal areas, and equinus
foot deformity. These patients had muscle hypotrophy of the
proximal and distal parts of lower extremities. Active move-
ments in the lower extremities was completely absent, and the
passive range of motion remained within 5to10at all joints.
Neurological status of patients with type III caudal regres-
sion included peripheral lower extremity paraparesis, mainly in
the distal lower extremities. Pain and thermal senses were pre-
served. Examination revealed bowel and bladder dysfunction.
Neurologic deficit in type IV caudal regression was manifested
by lower extremity paraplegia, absence of pain and thermal
sense in lower extremities, and bowel and bladder dysfunction.
Imaging
According to findings of X-ray examination, the mean preo-
perative kyphotic angle of spinopelvic segment as defined by
the above-mentioned method was 60(range ¼45to 73)in
patients with type III caudal regression and 75(range ¼45to
100) in patients with type IV caudal regression.
Tables 1 and 2 show that patients with type III lumbosacral
agenesis had greater number of intact segments of the spine and
spinal cord as compared with those with type IV.
Surgical Results
The performed surgical treatment corrected abnormal kyphosis
and prevented spinopelvic instability. Three patients with type
III caudal regression showed an improvement in motor func-
tion manifesting as the ability to ambulate independently.
These children also improved the bowel and bladder function
in the form of independent urge and control of urination and
defecation.
Postoperative X-rays showed mean angle of spinopelvic
segment to be 29.7(range ¼28to 32) in patients with type
III lumbosacral agenesis and 33.2(range ¼14to 55)in
patients with type IV lumbosacral agenesis. According to the
CT scans, a solid bone fusion was formed in the area of surgical
intervention between the caudal segment of the spine and pel-
vis in all patients at 2 to 2.5 years after surgery, providing
stability at this level (Figure 4). None of the patients underwent
the removal of spinal implant after surgery.
Five patients had complications after surgery. Delayed
wound healing was observed in 3 patients in the early post-
operative period (25%), leading to healing by secondary heal-
ing with the use of special wound dressings. In 2 patients
(16.6%), loosening of the pelvic implants was observed. These
patients underwent revision surgery to improve pelvic ancho-
rage. At latest follow-up all fixations were stable without loss
of correction. Neurological status that was gained in surgery
was not lost and the children remained ambulators. None of the
complications affected the long-term outcome of the patients.
Discussion
Caudal regression syndrome is a grave congenital defect, and
the absence of surgical care and correction of the deformity and
stabilization of the spine has a significant impact on the func-
tion of the visceral organs and shortens the life expectancy of
the patients.
4
The surgical treatment in caudal regression syn-
drome is difficult with a high complication rate.
4
Surgery needs
to reduce kyphosis and allow a balance of sitting and standing
positions with balanced sagittal profile. In this series, all
patients presented showed elimination of pathological kypho-
sis, restoration of support ability of spinopelvic segment, and
creation of functionally favorable conditions for the growth and
development of the spine and visceral organs.
The improvement of motor activity and bowel and bladder
function in patients with type III caudal regression was, in our
opinion, due to elimination of the kyphotic component of
deformity and instability at the level of the spinopelvic seg-
ment. This enabled the verticalization of patients, more favor-
able biomechanics of the spine, and physiological arrangement
of visceral organs.
In patients with type IV caudal regression, the performed
correction of deformity of spinopelvic segment combined with
bone grafting created the conditions for support ability of the
spine and provided an opportunity for physiological sitting and
further social rehabilitation.
It should be noted that the exact numerical measurement of
the kyphosis of spinopelvic segment is challenging since this
congenital malformation of the spine and spinal cord implies
the absence of sacrococcygeal joint and/or lumbar spine, and in
some cases of the lower thoracic spine. To reliably assess the
spatial position of the spine and pelvis and objectify the results
of surgical treatment, the method for measuring kyphosis of the
spinopelvic segment in children with caudal regression syn-
drome was developed by the authors and used here.
There is little data regarding the optimal correction of this
rare condition. Older techniques did not use modern instrumen-
tation
17
and lacked full correction of the deformity. Freland
et al
17
described a case series of 6 patients that used vascular
rib grafts with complete correction of the deformity. This tech-
nique requires harvesting of the ribs and additional surgery is
not needed in the technique described here. Fusion rates in both
series are high; however, the complication rate was higher in
their series, reaching 7 revision procedures in 4 patients (66%
complication rate) versus 5 complications in the series pre-
sented here (41.6%complication rate).
Complications that occurred in the early postoperative
period in the form of delayed healing of surgical wounds can
be attributed to severe impaired trophism of soft tissues caused
by the initial neurological deficit in patients with caudal regres-
sion syndrome. Destabilization of the implant was observed in
the first patient under our supervision, and in a child aged 9
years. In the first case, the complication was explained by the
learning curve needed with inferior selection of appropriate
anchoring elements and methods of deformity correction and
maintaining the achieved results. In the second case, a
Vissarionov et al 5
complication was associated with severe rigid deformity of the
spine due to the patient’s age and with challenges in its correc-
tion. Anchoring elements in both cases were hooks inserted
into pelvic bones.
The limitations of the study are its retrospective nature and
small number of patients; however, it is one of the largest series
on this pathology documented.
Conclusion
Patients with types III and IV caudal regression syndrome are
characterized by the presence of kyphosis and instability at the
level of spinopelvic segment. In our view, such patients should
undergo surgical treatment early in life.
Surgical treatment is aimed at eliminating abnormal kypho-
sis and instability at the level of spinopelvic segment. Appli-
cation of metal implant with multiple anchoring elements in
combination with spinopelvic fusion with cortical allografts
allows not only to solve the problem described above but also
to form the sagittal profile of the spine, create its support abil-
ity, achieve a bone block in the area of intervention, and main-
tain the achieved result in the late postoperative period. All this
enables the improvement of motor activity and verticalization
of patients, development of the spine in the process of growth,
and social adaptation of the children.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to
the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, author-
ship, and/or publication of this article.
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6Global Spine Journal
