Developmental Deformitiesof the Spine in Children With Myelomeningocele Abstract The treatment of spinal deformities in children with myelomenin-gocele poses a formidable task.. The two
Trang 1Developmental Deformities
of the Spine in Children With Myelomeningocele
Abstract
The treatment of spinal deformities in children with myelomenin-gocele poses a formidable task Multiple medical comorbidities, such as insensate skin and chronic urinary tract infection, make care of the spine difficult A thorough understanding of the natural history of these deformities is mandatory for appropriate treatment
to be rendered A team approach that includes physicians from multiple specialties provides the best care for these patients The two most challenging problems are paralytic scoliosis and rigid lumbar kyphosis The precise indications for surgical intervention are multifactorial, and the proposed benefits must be weighed against the potential risks Newer spinal constructs now allow for fixation of the spine in areas previously difficult to instrument Complications appear to be decreasing with improved understand-ing of the pathophysiology associated with myelomenunderstand-ingocele
Scoliosis and kyphosis with sec-ondary adaptive changes are common in the patient with myelo-meningocele Developmental defor-mities are acquired and are related to the level of paralysis; congenital de-formities result from malforma-tions, such as hemivertebrae Both forms may exist concurrently
From 1983 to 1990, the preva-lence of neural tube defects (ie, my-elomeningocele) in the United States was 4.6 per 10,000.1However, with the increased awareness of the im-portance of folic acid consumption during pregnancy, there has been a decrease of between 72% and 100%
in the number of overall new neural tube defects.1 Nearly every patient with myelomeningocele will de-velop hydrocephalus, and approxi-mately 50% of all patients will have
some degree of mental retardation The clinical experience of the au-thors has shown that most of these patients have motor levels at the lumbosacral or sacral level As the motor level ascends the spine, the prevalence of scoliosis and associ-ated musculoskeletal anomalies in-creases
Prevalence of Spinal Deformity
Multiple studies document the so-called incidence of the various types of spine problems in children with myelomeningocele at different ages.2-7Whether these numbers rep-resent an actual incidence or a prev-alence is unknown Cobb measure-ments also have been used to define developmental scoliosis, the
preva-James T Guille, MD
John F Sarwark, MD
Henry H Sherk, MD
S Jay Kumar, MD
Dr Guille is Orthopaedic Surgeon,
Shriners Hospital for Children,
Philadelphia, PA Dr Sarwark is
Chairman, Department of Orthopaedic
Surgery, The Children’s Memorial
Hospital, Chicago, IL, and Professor of
Orthopaedic Surgery, Northwestern
University Feinberg School of Medicine,
Chicago Dr Sherk is Professor,
Department of Orthopaedic Surgery,
Drexel University College of Medicine,
Philadelphia Dr Kumar is Director,
Spinal Dysfunction Clinic, Alfred I.
duPont Hospital for Children,
Wilmington, DE, and Clinical Professor
of Orthopaedic Surgery, Jefferson
Medical College of Thomas Jefferson
University, Philadelphia.
None of the following authors or the
departments with which they are
affiliated has received anything of value
from or owns stock in a commercial
company or institution related directly or
indirectly to the subject of this article:
Dr Guille, Dr Sarwark, Dr Sherk, and
Dr Kumar.
Reprint requests: Dr Guille, Shriners
Hospital for Children, 3551 North Broad
Street, Philadelphia, PA 19140.
J Am Acad Orthop Surg
2006;14:294-302
Copyright 2006 by the American
Academy of Orthopaedic Surgeons.
Trang 2lence of which ranges from 52% to
89% in this population The
preva-lence of congenital scoliosis ranges
from 7% to 20% More than 80% of
patients aged >10 years will have
scoliosis Using rigid criteria,
Trive-di et al2 recently defined
develop-mental scoliosis in this patient
pop-ulation as a Cobb magnitude >20°
This figure was chosen because
curves of less than this magnitude
often were observed to improve or
even to resolve The authors
con-cluded that when a scoliosis did not
develop by age 15 years, the child
would not develop a curve later in
life
Associated Health
Issues
The global health concerns in these
children are numerous and may
dra-matically influence the care of the
spinal deformity Common issues
include central nervous system
in-volvement, such as mental
retarda-tion, hydrocephalus requiring
shunt-ing, and tethering problems of the
brain and spinal cord Insensate skin,
latex allergy, renal anomalies,
bacte-rial colonization of the urinary tract,
bowel and bladder incontinence, and
lower extremity malalignment are
other factors that often require
eval-uation and treatment Ongoing care
and assessment are most effectively
done by a team approach In addition
to the orthopaedic surgeon,
mem-bers of the team should include a
pe-diatrician, neurosurgeon, urologist,
physiatrist, orthotist, physical
ther-apist, and social worker
Renal anomalies occur in 4% to
17% of patients with
myelomenin-gocele, with a higher association in
those with congenital vertebral
anomalies.8Aplasia or dysgenesis of
the kidneys is associated with
tho-racic and upper lumbar level defects;
anomalies of the ureters, especially
duplication, are associated with
low-er lumbar and sacral level defects
Secondary changes, such as scarring,
may occur in the urinary tract as a
result of chronic or recurrent infec-tion Therefore, renal dysfunction is common and requires routine mon-itoring
Latex allergy occurs in 18% to 40% of patients with myelomenin-gocele and may be life-threatening.9 The allergy is a type I immunoglob-ulin E (IgE)-mediated response to natural plant antigens in the latex and is not an actual allergy to the la-tex itself Repeated exposure to lala-tex products (from urinary catheteriza-tions, hospitalizacatheteriza-tions, or surgical procedures) ultimately may sensi-tize these patients to these antigens
The value of an allergen-specific IgE antibody test in detecting indi-viduals with latex allergy is ques-tionable; therefore, a latex-free pro-tocol should be used for every patient at all times
Musculoskeletal Evaluation
A complete history and baseline physical examination by the
special-ty team should be done in every child Serial examinations are rec-ommended every 4 to 6 months to document changes in neurologic and functional status The extremities are examined for range of motion, muscle strength, and the presence of skin ulcers or breakdown Truncal and sitting alignment are evaluated, with decompensation and rotational prominences noted Wheelchair and prosthetic modifications are made as needed in consultation with the ap-propriate skilled vendor and thera-pists
Baseline radiographs should be done of the entire spine in the an-teroposterior and lateral planes, with notation made as to whether the ra-diographs were made in the supine, sitting, or standing position Except
in low lumbar and sacral level pa-tients who can stand independently, radiographs preferably are done in the sitting position Evidence of deformity, associated congenital anomalies, and the level of the
spi-nal dysraphism should be recorded Serial radiographs should be per-formed every 6 months to document curve stability or progression A magnetic resonance imaging (MRI) study of the brain and spinal canal should be done within the first
2 years of life for baseline purposes; studies should be repeated when clinically indicated Myelography is reserved for patients in whom the spinal deformity is sufficiently se-vere to preclude adequate interpreta-tion of MRI scans, in patients with metal implants, and as part of the evaluation of a child with a tethered cord.10
Anomalies of the central nervous system include hydrocephalus, cere-bellar malformations, hydromyelia, syringomyelia, spinal cord anoma-lies, and tethered cord After birth but before discharge, >90% of chil-dren with myelomeningocele
devel-op hydrocephalus and a Chiari II malformation following spinal/skin closure Hydromyelia and syringo-myelia have been reported in ap-proximately 50% of patients.5,10 At-rophy of the spinal cord is seen in 15% of patients, lipomas and der-moids in 11% to 38%, and diastem-atomyelia in 2% to 7%; any of these anomalies may cause neurologic de-terioration Scoliosis associated with hydromyelia or syringomyelia is typ-ically an S-shaped curve in the tho-racic or thoracolumbar region No good guidelines exist as to when and how a syringomyelia becomes symp-tomatic and when it should be drained; evaluation of a syringomy-elia requires the consultation of a neurosurgeon MRI is a mainstay in detecting and monitoring these con-ditions
Signs of a tethered cord in the pa-tient with myelomeningocele can include deterioration in gait, increas-ing spasticity, weakness, limb defor-mities, back pain, changes in conti-nence, and rapid increase in the curve magnitude of scoliosis.11,12 The curve, when present, is usually
in the thoracolumbar or lumbar
Trang 3re-gion and is associated with increased
lumbar lordosis Some authors now
think that the signs of a tethered
spi-nal cord are a result of pressure on
the cord from repeated flexion and
extension of the spine at the site
causing focal flattening, rather than
from an actual tethering effect on
the ascent of the spinal cord.11
Sar-wark et al12 found that in a select
group of children with L3 motor
lev-el or lower and no hydromylev-elia,
re-lease of a tethered cord resulted in a
58% chance of stabilization or
im-provement of curve magnitude
Equivocal results also were seen in
patients with spasticity Pierz et
al11found no improvement in curve
magnitude following detethering in
patients who presented with
thorac-ic neurologthorac-ic levels or a curve >40°
Developmental
Scoliosis
Frequently seen in young children,
developmental scoliosis primarily
re-sulting from paralysis typically is a
long, sweeping, C-shaped curve with
or without pelvic obliquity The
con-vexity of the curve often is opposite
the side of the elevated pelvis A
dis-location of the hip alone does not
ap-pear to be the cause of the scoliosis;
the curve develops from muscle
im-balance secondary to paralysis and is
commonly associated with kyphosis,
not lordosis Often upper extremity
function is diverted because the
hands are used to support the trunk
Many factors correlate with the
occurrence of developmental
scolio-sis Clinical motor level is an
impor-tant predictor.2,6Trivedi et al2found
the prevalence of scoliosis to be
93%, 72%, 43%, and <1%,
respec-tively, in patients with thoracic,
up-per lumbar, lower lumbar, and sacral
motor levels The level of the last
in-tact laminar arch (LILA) is another
important predictive factor in the
development of scoliosis.4,7Trivedi
et al2found the prevalence of
scolio-sis to be 89%, 44%, 12%, and 0%,
respectively, in patients with
thorac-ic, upper lumbar, lower lumbar, and sacral LILAs The LILA is not always synonymous with the motor level
Overall, it appears that the three most important factors in predicting the development of scoliosis are the motor level, ambulatory status, and LILA To a lesser degree, hip dislocation/subluxation and lower extremity spasticity also are predic-tive factors
Muller et al13studied the progres-sion of scoliosis in 64 patients The fastest progression was seen during the early teenage years, although it may occur earlier; the scoliosis typ-ically stopped with the cessation of growth Progression was found to be related to the size of the curve:
curves <20° progressed slowly, whereas those >40° progressed more quickly (approximately 13° per year)
Nonambulatory patients had a
great-er progression rate; howevgreat-er, no cor-relation was made between the
lev-el of spinal defect and progression
The authors concluded that all curves should be observed closely and treated before a magnitude of 40° is reached Marchesi et al14also found that scoliosis is a progres-sive condition, especially in
young-er children, and that thyoung-ere was less chance for progression when the curve was detected after age
10 years
In a child with a scoliosis <20°, observation with radiographs every
4 to 6 months is suggested When the curve is >20°, use of a brace should be considered Because the role of bracing in these patients is controversial, its use is left to the choice of the surgeon and his or her experience Although most agree that bracing does not stop curve pro-gression or completely eliminate the need for spinal fusion, bracing may slow the progression of a curve and allow for further trunk growth be-fore eventual spinal fusion
Muller and Nordwall15 reported
on the use of the Boston brace in the management of scoliosis and found that when treatment was instituted
early and before the curve reached 45°, the brace could arrest progres-sion of the curve These results, however, have not been reported by others The brace we have recom-mended is custom-molded and does not interfere with pulmonary function, lower extremity bracing, self-catheterization, or sitting—a challenge in some patients Obesity may be a relative contraindication The brace aids in sitting balance and frees the hands for function Patients who use a brace need to have their skin checked daily for areas of pres-sure and breakdown, although a custom-fitted brace usually avoids these problems
Surgical Indications and Principles
Listing the absolute indications for surgical intervention is difficult because the long-term natural
histo-ry of untreated spinal deformity in this population is relatively un-known Most agree, however, that progressive scoliosis >50° that
caus-es sitting imbalance is an important indication McMaster16thought that loss of function as an indication was more important than the degree of curvature Ideally, spinal reconstruc-tion would be done after most adult sitting height is attained; however, the surgeon is infrequently afforded this optimal scenario
Because it is common for sur-geons to want to procrastinate in treating these curves surgically, a di-lemma arises when a younger child presents with a large progressive curve and sitting imbalance The ideal solution to this problem has yet to be found The use of a growing rod system in these patients has been reported Medical comorbidi-ties, such as shunt function, pulmo-nary function, skin condition, and urinary tract infection, require eval-uation and treatment before surgery When poor tissue coverage is a con-cern, consultation with a plastic sur-geon is advised to consider the use of preoperative tissue expanders
Trang 4Combined anterior and posterior
arthrodesis and instrumentation
provide the best chance to achieve a
durable fusion.16-20Anterior
diskec-tomy improves the
preinstrumenta-tion flexibility and correctability of
the curve, and anterior interbody
fu-sion increases the strength of the
en-tire fusion mass The addition of
al-lograft bone may be necessary in
patients who have had prior bone
graft harvesting, in those with small
ilia, and in those requiring long
fu-sions Bone graft substitutes and
growth factors may play an
impor-tant role in the future
Anterior fusion and
instrumenta-tion alone is again being considered
for selected curves Sponseller et
al21revisited this technique and had
good results with anterior fusion
alone only when the thoracolumbar
curve was <75°; when there were no
syrinx, no increased kyphosis, and
no compensatory curve >40°; and
when there was independent sitting
balance Parsch et al19recommended
instrumented anterior and posterior
fusions, especially in patients with
thoracic level paralysis, to decrease
the rate of implantation failure and
to prevent postoperative loss of
cor-rection In the series of Stella et al,22
the best corrections were obtained in
patients who had instrumented
an-terior and posan-terior fusions
The fusion should extend from
the upper thoracic vertebrae to the
sacrum in nonambulators and
should include all curves Careful
consideration should be given to the
type of posterior incision and
surgi-cal approach Although either a
transverse or triradiate incision
of-fers better exposure laterally, the
triradiate incision is associated with
a 40% rate of skin necrosis;18
there-fore, a single longitudinal straight
in-cision generally is preferred Wide
flaps should be developed laterally to
aid in wound closure
Instrumentation without spinal
fusion is not recommended in this
patient population; neither is fusion
without instrumentation, except for
congenital anomalies requiring in situ fusions Segmental posterior in-strumentation provides a means of curve correction and all but elimi-nates postoperative immobilization
Posterior spinal fusion with instru-mentation alone has unacceptably high rates of failure.20,23 Instrumen-tation of the dysraphic spine is diffi-cult, and the surgeon must use skill and experience in determining surgical strategies and in choosing the vertebral elements to the im-plant When laminae are present, sublaminar wires or cables are passed in the standard caudocepha-lad fashion; when laminae are ab-sent, drill holes may be made in the vertebral bodies for anchor sites
Pedicle screw fixation offers many solutions; in this population, how-ever, the pedicles often are small, dysplastic, and maloriented Rodgers
et al24have shown that pedicle screw instrumentation allowed preserva-tion and correcpreserva-tion of lumbar lordo-sis and that the anterior approach possibly could be avoided This tech-nique also may allow the surgeon to end the fusion above the sacrum, which may be beneficial in select ambulatory patients Multihook sys-tems are effective in the thoracic spine in which the anatomy is more nearly normal Consideration should
be given to the use of titanium im-plants if MRI studies of the region will be needed later Sacral and pel-vic fixation generally is thought to be mandatory in patients with fixed pel-vic obliquity However, Wild et al25 reported spontaneous correction of the pelvic obliquity following ante-rior and posteante-rior spinal fusion
Use of the Galveston technique may be challenging secondary to small, dysplastic, osteoporotic ilia
The Dunn-McCarthy or Warner-Fackler techniques of sacral fixation may be preferred in these pa-tients.26-29 Postoperatively, the pa-tient should be mobilized as soon as possible When stable, rigid fixation
is achieved, postoperative immobi-lization with a cast or brace is
op-tional and left to the surgeon’s dis-cretion Prolonged postoperative immobilization is associated with skin problems as well as fractures from disuse osteoporosis
Complications
Spinal surgery in this challenging patient population is associated with higher rates of complication.18,23 Wound infection may occur in up to half of these patients, as well as inci-sional necrosis (commonly seen when a triradiate incision is used) However, Ward et al18found no long-term disability from incisional skin necrosis in their patients Infection rates have approached 43% and are highest when surgery is performed with concurrent urinary tract infec-tion.18Preoperative urinary cultures are mandatory, as is treatment with antibiotics preoperatively and post-operatively
Foley catheters should be re-moved as soon as the patient is med-ically stable Intravenous antibiotics should be continued postoperatively until discharge The rate of neuro-logic deficit is low but can be perma-nent.18,30 Cerebrospinal fluid leaks may occur as a result of the surgical dissection or tethering of the spinal cord Progression of the curve may occur above and below the fusion mass when selection of the fus-ion levels is inappropriately short Pseudarthrosis occurs in up to 76%
of patients and is related to the sur-gical approach, type and presence of instrumentation, or use of a
posteri-or approach alone.20,22The pseudar-throsis rate is 0% to 50% with an isolated anterior arthrodesis, 26% to 76% with an isolated posterior ar-throdesis, and 5% to 23% with a combined anterior and posterior ar-throdesis (Figure 1) Pseudarthrosis secondary to implant failure has oc-curred in up to 65% of cases.16,18,30 Fractures of the extremities second-ary to disuse osteoporosis from im-mobilization are common Shunt malfunction may occur following acute correction of large curves.23
Trang 5In more than half of patients
in some series, reduced walking
ability in preoperative ambulators
af-ter surgery has been reported.30,31
There may occasionally be an
im-provement in activities of daily
liv-ing (eg, sittliv-ing balance), but hip
flex-ion contractures may increase A
greater potential for ambulation
ex-ists when the scoliosis is <40° and
pelvic obliquity is <25° The
eval-uation of postoperative patient
activ-ity (and function) is multifactorial
and can be affected by older age,
obe-sity, neurologic level, central axis
le-sions, and motivation of the patient
Improved pulmonary function has
been reported after anterior and
pos-terior spine fusion procedures.32
Pa-tients may have problems with self-catheterization after spinal surgery;
however, in these situations, modal-ities such as mirrors with central holes can be used by the patient As
an alternative, urologic bladder di-version procedures may be per-formed Skin sores may develop when changes in sitting balance re-distribute pressure on the skin
Congenital Scoliosis
Congenital scoliosis in the patient with myelomeningocele should be treated using the same principles as those used in otherwise normal chil-dren The natural history of this anomaly is similar in children both
with and without a myelomeningo-cele In both clinical settings, a strong association between the pres-ence of congenitally dysplastic ver-tebrae and renal anomalies exists
Rigid Lumbar and Thoracolumbar Kyphosis
Banta and Hamada33found that 46 of
457 patients had developmental ky-phosis, rigid congenital kyky-phosis, or kyphoscoliosis that progressed an average of 8°, 8.3°, and 6.8° per year, respectively.34The prevalence of
rig-id kyphosis of the lumbar spine
rang-es from 8% to 15%, depending on the series.35-38The curve may be ini-tially large at birth, and progression can range from 4° to 12° per year.39 Mintz et al35 reviewed 51 children who had a rigid kyphosis at birth;
40 of these patients had a thoracic level paralysis, and 9 of the remain-ing 11 patients had grade 3 motor strength in the quadriceps Progres-sion becomes more rapid after the first year of life, when the child be-gins to sit The fixed compensatory thoracic lordosis, so commonly seen
in older patients, is not present at birth and progresses by
approximate-ly 2.5° per year.36 Children with rigid lumbar ky-phosis have a characteristic clinical appearance: they sit on the posterior aspect of the sacrum with a protu-berant abdomen and kyphotic gib-bus Occasionally, an extension de-formity of the cervical spine may develop to balance the trunk The legs appear to be long because of the flexed position of the pelvis, and the lower ribs are splayed later-ally These children usually are more severely neurologically in-volved, have a higher prevalence of hydrocephalus, and have a poorer quality of life Thoracolumbar ky-phosis is characterized by a collaps-ing C-shaped curve with its apex found in the lower thoracic or lum-bar region; it is supple early but can become rigid
Figure 1
Postoperative images of a patient with myelomeningocele scoliosis A,
Anteropos-terior radiograph following anAnteropos-terior fusion with placement of interbody cages and
posterior fusion/instrumentation to the sacropelvis Note restoration of coronal
bal-ance B, Lateral radiograph demonstrating restoration of sagittal balbal-ance.
Trang 6Atrophic or absent erector spinae
muscles allow the quadratus
lumbo-rum muscle to become a flexor of
the spine.37The erector spinae
mus-cles, when present and functioning,
act as flexors of the spine in their
po-sition anterior to the pedicles
Hy-pertrophic psoas muscles also may
act as flexors of the spine, along with
the crura of the diaphragm The
dys-plastic laminae and pedicles are
di-rected laterally, and the
interverte-bral articulations are absent or
rudimentary With the development
of sitting, the increased moment
arm and physiologic load lead to a
progressive kyphotic deformity,
which continues until the vertebral
bodies become wedge-shaped
ante-riorly and the rib cage rests on the
pelvis
The rationale for surgical
treat-ment of rigid lumbar kyphosis is
based on many functional factors,
but the absolute criteria remain
ill-defined The deformity is
progres-sive in all cases and is recalcitrant to
nonsurgical treatment The
abnor-mal sitting posture often forces the
child to rely on the hands for
sup-port, thus diverting their use from
functional activities Repeated
epi-sodes of skin breakdown occurring
over the apex of the kyphosis are
dif-ficult to prevent and create risk for
the patient These two clinical
sce-narios—abnormal sitting and skin
breakdown—are perhaps the most
compelling reasons for surgical
in-tervention Compression of the
ab-dominal contents from the kyphotic
deformity also has been suggested as
a theoretic concern, yet no study has
documented functional benefits
re-lated to this parameter following
kyphectomy Families often worry
about shortened trunk height;
how-ever, performing multilevel
corpec-tomies and osteocorpec-tomies may
exacer-bate this problem Respiratory
compromise in untreated deformity
also is a concern However, most of
these patients have low aerobic
de-mand, and adaptive changes (eg,
flared ribs, barrel-shaped chests) may
partially compensate Martin et al38 showed that, with wheelchair mod-ifications, these children can do well and may complain only of the cos-metic deformity
The most appropriate timing and the optimal type of surgery are areas
of controversy Bracing can be used early to slow the progression of de-formity, but a surgical intervention
is nearly always required As the child ages, the deformity becomes more rigid, and a compensatory fixed thoracic lordosis develops Initial at-tempts at correction involve resec-tion or osteotomy of the apical ver-tebrae, with little attention directed
to the proximal thoracic lordosis
Proponents of neonatal kyphectomy
at the time of closure of the my-elomeningocele report that the pro-cedure is safe and provides good initial correction.40Even though re-currence of the kyphosis was com-mon, the new deformity was less
rig-id and easier to address.40 More extensive fusion and instrumenta-tion are required in the older child, and complication rates are higher.41 These children also require an ex-tensive preoperative evaluation An area of interest has been determining the course of the abdominal aorta42
as well as the method of most effec-tive evaluation (ie, aortography, MRI, ultrasound, computed tomog-raphy) All published studies noted here have shown that the abdominal aorta does not follow the path of the kyphosis and is at little risk during kyphectomy Preoperative shunt function should be tested When cor-dotomy is to be performed, the pro-cedure should not be done at the same level of the dura This will al-low the cerebrospinal fluid to circu-late and avoids an increase in intra-cranial pressure Lalonde and Jarvis43 showed that cordotomy al-lows for better correction,
potential-ly decreasing spasticity and poten-tially positively affecting bladder function However, undertaking a cordotomy increases surgical time and the degree of blood loss
For thoracolumbar kyphosis, Lindseth and Stelzer39described re-moval of the cancellous bone from the vertebra above and the one be-low the apical vertebra, which can
be performed at any age The poste-rior elements are removed, and an eggshell-type procedure is performed without violating the end plates The apical vertebra is then pushed forward, thus correcting the kypho-sis Fusion is done posteriorly only
so that continued anterior growth may provide further correction of the kyphosis Fixation is with tension-band wiring around the pedicles in younger children and with sublaminar wires, pedicle screws, and rods in older children For rigid lumbar kyphosis, the pro-cedures include kyphectomy as de-scribed by Lindseth and Stelzer.39 This entails resection or osteotomy
of the proximal portion of the apical vertebra of the gibbus and of the dis-tal segments of the adjacent lordosis, with limited fusion and wire fixa-tion.44In 39 patients (average
follow-up, 11.1 years), Lintner and Lind-seth44reported that 34 had a partial loss of correction, but only 2 patients settled into a position worse than their preoperative deformity The three remaining patients maintained their correction In the younger child, the kyphectomy is followed by a lim-ited fusion to preserve growth of the adjacent vertebrae In the older child, kyphectomy should be accompanied
by more extensive fusion and instru-mentation to the pelvis or sacrum (Figure 2) The optimal instrumenta-tion and distal fixainstrumenta-tion technique have yet to be determined.45-48 Sarwark49 reported on the sub-traction osteotomy of multiple ver-tebral bodies at the apex, which cre-ates lordosing osteotomies at each level.50 The vertebral body can be entered and subtracted via the pedi-cles with a curette, distal to proxi-mal A closing osteotomy is then done posteriorly to obtain correc-tion This procedure is done in chil-dren younger than age 5 years and is
Trang 7supplemented with full sagittal
in-strumentation from the
midtho-racic level to the sacrum Excellent
correction and restoration of the
sagittal alignment can be obtained,
but long-term results after
comple-tion of growth are needed to observe
all related losses of correction
(Fig-ure 3) Reported advantages include
less blood loss, decreased morbidity,
no need for cordotomy, and
contin-ued growth because the end plates are not violated
Summary
Care of the child with myelomenin-gocele who has a spinal deformity, such as paralytic scoliosis or rigid lumbar kyphosis, is challenging be-cause of the presence of medical co-morbidities, such as central nervous
system involvement, renal anoma-lies, and potential latex allergy Eval-uation and management of these children requires a team approach with physicians from multiple spe-cialties Preoperative discussions with the patient and family must ad-dress their perceived as well as the actual benefits of treatment.51Early treatment, which may include com-bined anterior and posterior
arthro-Figure 2
Rigid lumbar kyphosis in a 13-year-old
boy A, Preoperative lateral radiograph showing a 119° curve B,
Antero-posterior radiograph showing minimal deformity in the coronal plane
C,Clinical photograph of the deformity Eighteen months postoperatively, there
is excellent correction in the
antero-posterior (D) and lateral (E) planes
following resection of the first and second lumbar vertebrae and instrumentation with Dunn-McCarthy rods (Case courtesy of B Stephens Richards, MD, Dallas, TX.)
Trang 8desis and instrumentation, anterior
diskectomy, anterior interbody
fu-sion, or the addition of allograft
bone, is required to avoid the
pro-gression of curves to severe
deformi-ty that later may require extensive
measures Besides using skill and
ex-perience during surgical procedures
of the spine, the surgeon must be
fa-miliar with and be prepared to use
different kinds of implants
Al-though the surgical treatment of
these patients remains difficult and
is associated with higher
complica-tion rates, new implant designs,
careful attention to detail, and
pre-operative planning can yield
suc-cessful results with minimal
associ-ated problems and complications
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Citation numbers printed in bold
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