Myelomeningocele (spina bifida): Orthopedic issues

INTRODUCTION — Myelomeningocele, also known as spina bifida, leads to bowel, bladder, motor, and sensory paralysis below the level of the spinal lesion. Patients with myelomeningocele can have other lesions of the spinal cord (eg, diastematomyelia or hydromyelia) or structural abnormalities of the brain (eg, hydrocephalus), which can also compromise neurologic function. (See "Myelomeningocele (spina bifida): Anatomy, clinical manifestations, and complications".)

Orthopedic abnormalities in patients with myelomeningocele are caused by unbalanced muscle action around joints, paralysis, and decreased sensation in the lower extremities [1]. Some of these problems are chronic or slowly progressive, and others may arise acutely because of progressive neurologic dysfunction, which might be caused by tethered cord or shunt malfunction.

The main goal of orthopedic care of a patient with myelomeningocele is to correct deformities that may interfere with function. For some patients, functional goals may include ambulation using orthoses [2]. In addition, the orthopedic surgeon must monitor spinal balance and deformity. Because acute changes in orthopedic problems can be caused by acute neurologic events, the orthopedic examination also helps to monitor the neurologic status of the patient.

Orthopedic care of the child with myelomeningocele is made challenging by the presence of multiple medical comorbidities that must be considered in any treatment plan. These comorbidities include central nervous system involvement (eg, hydrocephalus), spinal cord complications (eg, syringomyelia and tethering), urinary tract complications (eg, bladder incontinence and renal dysfunction), bowel incontinence, insensate skin, and latex allergy [3]. For this reason, whenever possible, orthopedic care should be rendered as part of a multi-disciplinary team, working together with neurosurgery, urology, and physiatry.

The evaluation and treatment of the common orthopedic problems that affect patients with myelomeningocele are discussed here. The management of their neurologic and urinary tract problems is discussed in separate topic reviews. (See "Myelomeningocele (spina bifida): Management and outcome" and "Myelomeningocele (spina bifida): Urinary tract complications".)

THE ORTHOPEDIC EXAMINATION

Overview — The initial evaluation in the newborn or older child with myelomeningocele should include identification of the level of paralysis for each extremity by a manual muscle test performed by a skilled physical therapist, and should identify associated pathology, such as clubfoot or hip or knee contractures.

The follow-up periodic orthopedic examination should include assessment of motor and sensory function, range of motion of the hip, knee, and ankle, spinal deformity, foot deformity, and integrity of skin. Changes should alert the clinician to the possibility of tethered cord. In addition, mobility and bracing needs should be addressed to ensure orthoses are appropriate, in good shape, and not causing any pressure points on the skin.

Special considerations — The clinician should be vigilant for several complications that are more common in patients with myelomeningocele as compared with typically developing patients:

●Latex allergy – Latex-free materials should be used for all patients to reduce the risk of developing latex allergy. Latex-free surgery is mandatory.

●Skin breakdown – Patients are at risk for skin breakdown because of decreased skin sensation and orthoses, so the skin should be inspected carefully and pressure points avoided.

●Pseudoarthrosis – Patients with myelomeningocele are at increased risk for pseudoarthroses (nonosseous union or "false joint") after attempted spinal fusion. (See 'Spine' below.)

●Pathologic fractures – Patients are at risk for pathologic fractures because of joint contracture, lack of protective sensation, and decreased bone density (due to paralysis and/or postsurgical immobilization, especially spica casting). Pathologic fractures are particularly prevalent in patients with a higher spinal cord level of neurologic involvement [1]. Fractures in children with myelomeningocele can present with marked swelling and redness and may be mistaken for cellulitis or osteomyelitis. Physeal fractures in children with myelomeningocele can compromise bone growth. In a patient with myelomeningocele, a warm, red, swollen extremity should be considered a fracture until proven otherwise.

●Delayed union – Patients with myelomeningocele have higher risk for delayed union (ie, prolonged or incomplete bone healing) after surgical procedures. Rigid internal fixation and meticulous surgical technique are used to decrease this risk.

Ambulation — Ambulation is an important goal for many children with myelomeningocele because it can provide physiologic and psychological benefits, even if the child will later become nonambulatory. Therefore, one of the main tasks of the orthopedic surgeon is to evaluate and correct hip, knee, and foot deformities to maximize the patient's ability to ambulate with the aid of orthoses.

Predictors of ambulation — Multiple factors affect the potential for ambulation in a given patient with myelomeningocele, including:

●Neurologic level of involvement

●Presence of hip or knee contracture

●Degree of scoliosis

●Presence of foot and ankle deformities

●Spasticity

●Age

●Obesity

One study of 98 patients at an average age of 14 years found that 20 of 21 patients with L5 or sacral level of involvement were able to ambulate moderate distances ("community ambulators") [4]. In the same study, most patients with spinal involvement at L4 were also community ambulators, but patients with spinal involvement at L3 or above were mostly unable to ambulate except for very short distances within the home (nonfunctional ambulators).

Another predictor for maintaining ambulation into adulthood is the strength of the quadriceps and hamstring muscles (of the anterior and posterior thigh, respectively), gluteus muscle (involved in hip abduction), and iliopsoas muscles (involved in hip flexion) [2-5]. In addition, one study found that achieving sitting balance was an important predictor of ambulatory potential in patients with higher spinal levels of neurologic involvement [6].

Functional classification — The patient's functional classification level predicts most clinical features. The Myelomeningocele Functional Classification (MMFC) (table 1) [7], which was revised and updated in 2021, has been shown to correlate well with walking activity [8] and is useful in assisting with management decisions. The MMFC consists of four groups:

●MMFC1 (approximately 30 percent of patients) – MMFC1 includes most patients with thoracic and high lumbar-level lesions (L1-L3). It is defined by lack of functional quadriceps activity.

During childhood, patients in this group require bracing to the level of the pelvis as well as an assistive device for ambulation. Due to the high energy cost required for ambulation with these orthoses, the majority of patients in this group use a wheelchair for all mobility in adulthood.

●MMFC2 (approximately 30 percent of patients) – MMFC2 includes patients with low lumbar-level lesions (L3-L5). It is defined by functional activity in the quadriceps and medial hamstrings and lack of functional activity of the gluteus medius and gastrocnemius-soleus.

During childhood, patients in this group ambulate with ankle-foot orthotics (AFOs) and a walker or forearm crutches. The majority of patients in this group retain the ability for community ambulation in adulthood but may use a wheelchair for long-distance mobility. Because of this potential to maintain community ambulation in adulthood, this group has the most benefit from proper orthopedic care of musculoskeletal deformities.

●MMFC3 (approximately 30 percent of patients) – MMFC3 includes patients with high sacral-level lesions. It is defined by functional activity in the quadriceps and gluteus medius and lack of functional gastrocnemius-soleus.

Most patients in this group ambulate independently with AFOs and do not require assistive devices. They have a gluteus lurch with excessive pelvic obliquity and rotation during gait.

●MMFC4 (approximately 10 percent of patients) – MMFC4 includes patients with low sacral-level lesions. It is defined by functional activity of the gastrocnemius-soleus, quadriceps, and gluteus medius.

Patients in this group ambulate without orthotics or assistive devices with a nearly normal gait pattern.

Functional mobility scale — The Functional Mobility Scale (FMS) is a quick, clinically practical tool for distinguishing between groups of children with varying levels of disabilities, and provides a means for standardized communication between health professionals (figure 1) [9]. It was originally developed as a tool to describe functional mobility in children with cerebral palsy [9], and was subsequently applied to children with myelomeningocele [10]. The score reflects the level of support needed (ranging from using a wheelchair or stroller to independent ambulation without walking aids) for mobility in each of three distances (5, 50, or 500 meters or yards, representing mobility in the home, at school, and in the community).

Gait analysis — Where available, computerized gait analysis is a valuable component of the comprehensive orthopedic evaluation of patients with low lumbar or sacral level myelomeningocele (MMFC levels 2 through 4 (table 1)). It has been used as part of the evaluation of many manifestations of myelomeningocele, including hip subluxation/dislocation, lower extremity contractures, and rotational abnormalities [11-14]. Gait analysis is especially useful in preoperative planning and in quantitatively assessing surgical results. One study of 43 ambulatory children with myelomeningocele found that gait analysis data improved the recognition of excessive hip flexion and abnormal femur rotation and that it changed surgical recommendations in 44 percent of patients [15].

Clinical evaluation of patients with myelomeningocele is complex and involves multiple interrelated levels of deformity. Often, a patient's true functional status is different from the function that would be predicted based on the static clinical examination [13]. This was demonstrated in a study examining crouched gait in patients with myelomeningocele [13]. In these patients, computerized gait analysis revealed significantly greater amount of dynamic knee flexion during ambulation as compared with that measured on clinical examination.

Orthopedic outcomes of fetal surgery — In some centers, fetal surgery is performed to achieve intrauterine closure of the myelomeningocele defect, with the aim of preventing progressive neural tissue destruction and improving neurologic outcomes.

The Management of Myelomeningocele Study (MOMS) was a multicenter randomized trial evaluating the safety and efficacy of fetal myelomeningocele surgery [16]. The participants of MOMS are being followed into childhood to evaluate the long-term effect of fetal intervention on motor function and other important outcomes. In a report of the 30-month outcomes for the full cohort, patients who underwent fetal surgery were more likely to have achieved independent ambulation compared with those who underwent postnatal repair (45 versus 24 percent, respectively) [17]. Other observational studies also suggest that fetal surgery may be associated with improved motor function compared with that predicted by prenatal anatomic level of the lesion [18,19]. Additional studies with longer follow-up are needed to more definitively answer the question as to whether fetal surgery improves motor function in the long term.

Fetal myelomeningocele surgery is discussed in greater detail separately. (See "Myelomeningocele (spina bifida): Management and outcome", section on 'Fetal surgery'.)

SPINE — Spinal deformity is the most frequently occurring orthopedic abnormality in patients with myelomeningocele [1]. Spinal deformity may be congenital or acquired and can manifest as kyphosis, scoliosis, or lordosis. These deformities can cause back pain due to muscle fatigue or costo-pelvic impingement, or difficulty with ambulation and transfers due to the loss of trunk balance. They may also affect appearance, with adverse effects on self-image and social interactions [20].

Kyphosis — Children with myelomeningocele are at risk for developing progressive kyphosis, either lumbar or thoracic. Lumbar kyphosis may be present at birth, and commonly increases once the child begins to sit. Children with lumbar kyphosis tend to have more severe neurologic involvement, a higher prevalence of hydrocephalus, and a poorer quality of life as compared with children without lumbar kyphosis [3]. Older patients with lumbar kyphosis often develop compensatory thoracic lordosis; this is not seen at birth and is also progressive.

Scoliosis — Progressive scoliosis in myelomeningocele can result from congenital vertebral malformations, muscular imbalance, and certain neurologic conditions (eg, syrinx or tethered cord). Scoliosis may develop gradually, in response to chronic neuromuscular dysfunction and skeletal growth, or rapidly, as a consequence of acute neurologic changes (such as tethered cord). (See "Closed spinal dysraphism: Pathogenesis and types", section on 'Syringohydromyelia' and "Closed spinal dysraphism: Pathogenesis and types", section on 'Tethered cord syndrome'.)

The prevalence of scoliosis in patients with myelomeningocele correlates with the level of the spinal cord neurologic deficit. Rates vary from 5 percent in patients with sacral level deficits, to 70 percent in patients with L3 level deficits, to over 90 percent in patients with deficits at L1 or above [20]. Thus, the clinician should be particularly vigilant for the development of scoliosis in patients with a high level of neurologic involvement.

Management — The indications for spinal fusion in children with myelomeningocele are controversial and in most cases decisions regarding surgery need to be individualized.

General considerations — When making decisions regarding surgical or nonoperative management, the provider, patient, and caregivers should recognize the following limitations of surgery:

●Although spinal fusion can reliably reduce curve magnitude, it has not been shown to improve walking ability in ambulatory patients, and may, in fact, result in decreased ambulatory function [21-24]. Studies have failed to show improvements in functional outcomes, such as ambulation, motor skills, and activities of daily living following spinal fusion [21,22,24,25].

●Patients with myelomeningocele have increased risks for implant failure, pressure sores, wound infections, and pseudoarthrosis compared with patients without myelomeningocele. (See 'Surgical complications' below.)

●A fused spine may interfere with bending for perineal care and self-catheterization, particularly for females. Most children with myelomeningocele have their spinal fusions extended to the pelvis. This loss of motion may increase the risk of pressure sores.

Mild to moderate curvature — In patients with spinal curves that are flexible and relatively mild (generally <50°), nonoperative intervention is preferred over surgery. Treatment consists of sitting supports, spinal orthoses, and functional strengthening programs designed to improve sitting balance and functional independence [20].

The goal of using an orthosis is to support the trunk in a functional position and to control the curve during growth, possibly delaying or avoiding the need for surgical stabilization [26]. It is not used to correct the deformity. When an orthosis is prescribed for a patient with myelomeningocele, it is imperative to ensure proper fitting and to monitor regularly for skin complications.

Kyphotic deformities do not respond well to nonsurgical intervention.

Severe curvature — For patients with severe scoliosis, the decision to offer surgical treatment depends in part upon whether the patient is ambulatory:

Nonambulatory patients — Surgical treatment can improve sitting balance [3,24]. Therefore, in our practice, we offer surgical intervention to nonambulatory patients who have difficulty with sitting or problems with skin breakdown that are attributable to the spinal deformity.

Ambulatory patients — In patients who are ambulatory, several studies suggest that spinal fusion may adversely impact the ability to ambulate, particularly if the fusion extends down to the sacrum [3,21,24]. Therefore, surgical decisions in ambulatory patients should be made on a case-by-case basis, after reviewing with the caregivers the potential benefits, risks, and uncertainties. Fusion to the sacrum should be avoided. (See 'General considerations' above.)

In patients with severe kyphosis, criteria are not well defined regarding indications for surgery, including type of procedure and timing of intervention [3]. In our practice, as we do for nonambulatory patients, we offer surgical intervention to those who have difficulty sitting or problems with skin breakdown that are attributable to the spinal deformity.

Surgical complications — Patients with myelomeningocele have increased risks for postoperative complications after scoliosis or kyphosis surgery, as compared with patients without myelomeningocele who undergo spine surgery. (See 'Special considerations' above.)

Commonly encountered complications include implant problems (such as implant failure, dislocation, and pseudoarthrosis), infections, problems with anesthesia, and neurologic complications. In a series of 77 patients with spina bifida treated with spine surgery, implant problems developed in 29 percent [27]. Pseudoarthrosis rates as high as 76 percent have been reported, depending upon the surgical approach [3]. Wound infections occur in up to one-half of patients [3]; the risk is increased by a concurrent urinary tract infection, which is common in this population.

HIP — Hip deformity in patients with myelomeningocele results from muscle imbalance and paralysis around the hip joint [1]. Hip deformity may present as contracture, subluxation, or dislocation. If not treated properly, contractures can lead to pelvic obliquity and compensatory scoliosis [1].

Treatment goals — Treatment goals should focus on maintaining hip range of motion. In the contemporary era, surgery is usually performed only to release contractures that negatively impact gait function. In the past, surgical treatment focused on reducing paralytic hip dislocations. However, subsequent studies suggested that this type of surgical intervention did not result in improved ability to ambulate, less need for bracing, or reduced pain [12,25,28-30]. Moreover, surgical complications (including loss of motion and pathologic fractures) occurred commonly, which further compromised ambulation [29,30].

The most important factor in determining ability to walk is level of neural involvement and not the status of the hip [12,28-31]. In a study involving 31 adults with myelomeningocele (thoracic-level in 8, lumbar-level in 9, and sacral-level in 14), patients with bilaterally located hips reported better lower extremity function and also more pain compared with patients with subluxed or dislocated hips [32]. However, these differences were no longer statistically significant after controlling for the neurologic level of the myelomeningocele.

Thoracic and lumbar-level myelomeningocele — Operative reduction of hip dislocation is generally not warranted in patients with Myelomeningocele Functional Classification (MMFC) level 1 or 2 (table 1). Management of hip subluxation or dislocation emphasizes preservation of muscle strength, specifically of the iliopsoas and the quadriceps. Treatment goals should include maintaining a level pelvis and free motion of the hips rather than radiographic reduction of the hip [29]. The treating surgeon must counsel patients and their caregivers appropriately so that the goals of surgery are clearly understood. In our practice, surgical treatment for hip dislocations is performed only for contracture release [12,29].

Sacral-level myelomeningocele — In patients with sacral-level myelomeningocele who walk without support (MMFC level 3 or 4 (table 1)) hip dislocation may cause an increased lurch due to the loss of a fulcrum from the dislocated hip. This patient population (which represents a small minority of patients with myelomeningocele) may therefore benefit from surgical reduction, though outcomes of surgery in this specific subgroup have not been described. In our center we treat hip instability in these patients with bilateral femoral osteotomy combined with pelvic osteotomy on the side of the instability.

ROTATIONAL ABNORMALITIES — Both ambulatory and nonambulatory patients with myelomeningocele frequently develop torsional deformities of the lower extremities.

Torsion is defined as twisting or rotation of a bone about its long axis. Normal healthy infants have some degree of femoral torsion at birth, and this usually decreases gradually as the child grows. However, in patients with myelomeningocele, the torsion often fails to decrease normally with growth because of abnormal gait and activity levels [1]. In patients with myelomeningocele, tibial torsion is even more common than femoral torsion. Tibial torsion can be either external, which is caused by muscle imbalance, or internal, which is congenital.

Nonambulatory patients — For nonambulatory patients, torsional deformities do not interfere with function, and intervention is not usually indicated.

Ambulatory patients — For ambulatory patients, torsional deformities often interfere with ambulatory function, and should be addressed.

Initially, most of these patients can be treated conservatively with orthoses, typically ankle-foot orthotics with attached twister cables, to improve gait function. The role of the orthopedic surgeon is to minimize bracing requirements while achieving as normal a gait as possible [33]. Often, surgical intervention is delayed until six years of age or older to decrease the risk of recurrence. Orthotic management is useful to maintain gait function until an appropriate surgical age is reached.

In patients who develop severe labored gait despite treatment with orthoses or those with difficulty with orthotic fitting (resulting in skin ulceration) and/or pain, we suggest surgical management with rotational osteotomy [11]. In this case, the treating surgeon should carefully assess the patient's gait to determine the extent of deformity correction needed before planning surgery, using computerized gait analysis, if available [2]. (See 'Gait analysis' above.)

In addition, it is essential to examine the patient's entire lower extremity, paying particular attention to the hindfoot because patients with external tibial torsion often have associated hindfoot valgus. Often, both deformities require treatment to achieve a successful result. (See 'Foot and ankle' below.)

Among patients treated with lower extremity osteotomies, 80 to 90 percent have good functional outcomes, as measured by gait parameters and range of motion [33,34]. Derotation osteotomy may also delay or prevent degenerative changes that may occur in patients with excessive external tibial torsion [11]. As an example, one study found increased valgus knee stress in each of eight patients with external tibial torsion, and this improved after derotational osteotomy [11].

Recurrence is not uncommon following surgery. In a case series of 82 children (129 limbs) who underwent tibial derotational osteotomy, the recurrence rate (requiring reoperation) was 16 percent [35]. Notably all of the limbs that required reoperation were initially treated for external torsion.

The potential benefits of surgery must be balanced with the risks for surgical complications. Patients with myelomeningocele have increased risks for delayed union (especially in tibial osteotomies), and wound infection [34]. (See 'Special considerations' above.)

FOOT AND ANKLE — Foot deformities are present in 80 to 95 percent of patients affected by myelomeningocele [1]. The spectrum of foot deformities includes clubfoot, calcaneus, equinus, varus, valgus, and vertical talus [36]. Intrauterine paralysis is a major contributing cause of congenital foot deformity and is exacerbated by increased intrauterine pressure and malposition [1].

Foot deformities can interfere with effective bracing that may be needed for ambulation. The deformities can also cause pressure sores, difficulty with shoe wear, and can be a cosmetic problem. The goal of orthopedic treatment is a plantigrade, flexible, braceable foot on which a shoe can be worn to allow ambulation.

The treatment principles for foot deformities can be stratified by severity and type of deformity. Deformities more likely to respond favorably to passive manipulation include equinus and mild positional clubfoot. Infants with these and other foot deformities should undergo a trial of gentle passive manipulation, taking great care to avoid skin complications [2]. The orthopedic surgeon must communicate to the caregivers that even if early correction is possible, recurrence is common, and future need for surgery is still a possibility. Surgery is typically performed around one year of age to facilitate brace wear, standing, and ambulation.

Virtually all children with myelomeningocele have absent or limited sensation on the plantar aspect of their feet. The caregivers should be counseled to not let their child go barefoot. Walking in a swimming pool without foot protection is a common cause of sores.

Clubfoot — Clubfoot (talipes equinovarus) is present in approximately 32 percent of patients with myelomeningocele and nearly always requires surgical correction (picture 1) [1]. Mild positional clubfoot in an infant may be addressed with passive manipulation, as described above.

The clubfoot deformity is often rigid, requires extensive surgery to correct, and has a propensity to recur. Postoperative casting must be carried out judiciously with regular inspection of the skin to prevent wound problems and pressure sores. After casting, bracing is required indefinitely.

The Ponseti method of clubfoot treatment with serial manipulation and casting has been attempted in patients with myelomeningocele. No long-term outcome data are available. However, one study reports successful initial reduction in 96 percent of patients [37]. Sixty-eight percent of these experienced relapse and required retreatment, but most of these were successfully treated without needing extensive soft-tissue release surgery. Risk of recurrence has been shown to be influenced by the type of Achilles tendon surgery performed. One study found that all patients who underwent percutaneous tenotomy (12 of 12) experienced recurrence, whereas only 18 percent of patients who underwent open excision of the Achilles tendon (2 of 11) had recurrences [38]. While the Ponseti method may be useful to prevent extensive soft-tissue release, caregivers should be counseled regarding the high risk of recurrence, potential need for further treatment, and risk of skin breakdown.

Surgical treatment consists of radical posteromedial-lateral release (PMLR). Good results have been reported in 61 to 83 percent of patients. Outcome varies with motor level of involvement. One study reported worse outcome following PMLR in patients with thoracic and high lumbar level myelomeningocele compared with those with low lumbar and sacral lesions (poor results occurred in 50 versus 11 percent, respectively) [39].

Calcaneus — Calcaneus is seen in approximately 35 percent of patients with myelomeningocele and is particularly common in those with L4 to L5 level involvement (picture 2) [1]. It results from muscle imbalance between the active dorsiflexors and paralyzed plantar flexors of the ankle, and causes difficulty with bracing and shoe wear.

One study reported a good result in 82 percent of calcaneus feet treated with anterior or anterolateral soft-tissue release [40].

Talus — Vertical talus (rocker bottom foot) is present in approximately 10 percent of patients with myelomeningocele, and usually requires surgical correction (picture 3) [1]. Promising initial results have been reported using a staged, minimally invasive approach that is similar to the Ponseti method for clubfoot, consisting of serial manipulation and casting followed by open pinning of the talonavicular joint and lengthening of the Achilles tendon. In a report of 15 consecutive children treated with this technique, initial correction was achieved in all patients and recurrence occurred in 5 out of 25 feet [41]. However, long-term outcomes with this procedure are not known.

When extensive soft-tissue release is necessary, good results have been reported with single-stage correction addressing both the hindfoot and the forefoot (PMLR) [42].

Cavovarus — Another pattern of foot deformity seen in patients with myelomeningocele is cavovarus (picture 4). This deformity is characterized by an elevated longitudinal arch (cavus). An inverted heel (varus) then results from the muscle imbalance between the posterior tibialis and the peroneal muscles. When the cavovarus is rigid, it often causes skin breakdown, difficulty with bracing, and problems with ambulation. Rapid development of progressive cavovarus can be caused by a tethered cord and should prompt a thorough neurologic evaluation. (See "Closed spinal dysraphism: Pathogenesis and types", section on 'Tethered cord syndrome' and "Closed spinal dysraphism: Clinical manifestations, diagnosis, and management", section on 'Evaluation and diagnosis'.)

A surgical technique combining joint-sparing osteotomies with appropriate soft-tissue releases has shown promise in patients with myelomeningocele and cavovarus deformities [43]. Fusions should be avoided whenever possible in this patient population that does not have protective sensation.

Valgus — Ankle valgus is another problem commonly seen in ambulatory patients with spina bifida (picture 5). This can lead to skin irritation and breakdown over the medial malleolus due to excessive pressure against the orthosis [2].

Surgical treatment for valgus ankle varies depending on the precise anatomical location of the deformity, which can arise from the distal tibia, subtalar joint, or both. Treatment options for distal tibia valgus include medial hemiepiphysiodesis of the distal tibia or, in severe cases, distal tibia osteotomy. For hindfoot valgus, treatment consists of a medial displacement osteotomy of the calcaneus.

ORTHOSES — In children with myelomeningocele, orthoses are used to maintain alignment, prevent deformity, correct flexible deformities, facilitate independent mobility, and protect the insensate limb.

In children with Myelomeningocele Functional Classification (MMFC) level 1 involvement (table 1), orthoses are used for upright weight bearing and mobility. Often these children have functional hip flexors and adductors, but poor quadriceps function. Hence, the orthoses need to cross and control the hip to maintain the trunk over the pelvis and lower limbs. Examples are hip-knee-ankle-foot orthoses or reciprocating-gait orthoses (picture 6).

Children with MMFC 2 or 3 level of involvement (table 1) often require orthoses due to absent hip extensors and abductors, as well as ankle plantar- and dorsi-flexors. Often they require a knee-ankle-foot orthosis or an ankle-foot orthosis (picture 7) to maximize gait efficiency and control the position of the foot.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Congenital malformations of the central nervous system".)

SUMMARY AND RECOMMENDATIONS

●Orthopedic abnormalities in patients with myelomeningocele are caused by unbalanced muscle action around joints, paralysis, and decreased sensation in the lower extremities. Deformities of the spine, hip, legs, ankle, and foot may contribute to functional problems with ambulation or other activities of daily living. The main goals of orthopedic care in children with myelomeningocele are to maximize function and mobility and minimize deformity and pain. (See 'Introduction' above.)

●Rapid development of an orthopedic problem such as scoliosis or foot deformity may be caused by an acute neurologic problem (eg, tethered cord or shunt malfunction) and should prompt a thorough neurologic evaluation. (See "Myelomeningocele (spina bifida): Management and outcome", section on 'Neurologic complications'.)

●Common orthopedic problems affecting patients with myelomeningocele include:

•Scoliosis – Spinal deformity is the most frequently occurring orthopedic abnormality in patients with myelomeningocele. Spinal deformity may be congenital or acquired and can manifest as kyphosis, scoliosis, or lordosis. These deformities can cause back pain due to muscle fatigue or costo-pelvic impingement, or difficulty with ambulation and transfers due to the loss of trunk balance. Treatment depends on the severity of the curvature (see 'Spine' above):

-For patients with mild to moderate scoliosis (a flexible curve <50°), treatment is nonoperative and may include sitting supports, spinal orthoses, and functional strengthening programs designed to improve sitting balance and functional independence. (See 'Mild to moderate curvature' above.)

-For nonambulatory patients with severe scoliosis, we offer surgical intervention if there are difficulties with sitting or problems with skin breakdown that are attributable to the spinal deformity. (See 'Nonambulatory patients' above.)

-For ambulatory patients with severe scoliosis, the role of surgery is controversial. Although spinal fusion can reliably reduce curve magnitude, it has not been shown to improve walking ability, motor skills, or activities of daily living in ambulatory patients and, in some cases, can result in decreased ambulatory ability. Thus, surgical decisions should be made on a case-by-case basis, after review of the potential benefits, risks, and uncertainties with the patient and caregiver. (See 'Severe curvature' above and 'General considerations' above.)

•Hip deformity – Hip deformity in patients with myelomeningocele results from muscle imbalance and paralysis around the hip joint and may present as contracture, subluxation, or dislocation. Treatment goals focus on maintaining hip range of motion (see 'Hip' above):

-For patients with thoracic or lumbar-level myelomeningocele (ie, patients who are unable to ambulate without an assistive device), operative reduction of hip dislocation is generally not warranted. In such patients, surgery to reduce the dislocation does not result in improved ability to ambulate, less need for bracing, or reduced pain. These patients may benefit from surgical release of contractures as needed to maintain a level pelvis and free motion of the hips. (See 'Thoracic and lumbar-level myelomeningocele' above.)

-In patients with sacral-level myelomeningocele who walk without support, hip dislocation may cause an increased lurch due to the loss of a fulcrum from the dislocated hip, and, therefore, operative reduction may be warranted in this subset of patients. (See 'Sacral-level myelomeningocele' above.)

•Femoral and tibial torsion – Both ambulatory and nonambulatory patients with myelomeningocele frequently develop torsional deformities of the lower extremities (see 'Rotational abnormalities' above):

-Most ambulatory patients with femoral or tibial torsion can be managed initially with orthoses. In patients who develop severe labored gait despite treatment with orthoses and those who have difficulty with orthotic fitting, resulting in skin ulceration and/or pain, we offer surgical intervention with rotational osteotomy. (See 'Ambulatory patients' above.)

-For nonambulatory patients, torsional deformities do not interfere with function and intervention is usually not warranted. (See 'Nonambulatory patients' above.)

•Foot deformities – The spectrum of foot deformities in patients with myelomeningocele includes clubfoot, calcaneus, equinus, varus, valgus, and vertical talus. Intrauterine paralysis is a major contributing cause of congenital foot deformity. Foot deformities can interfere with effective bracing that may be needed for ambulation. They can also cause pressure sores, difficulty with shoe wear, and can be a cosmetic problem. The goal of orthopedic treatment is a plantigrade, flexible, braceable foot on which a shoe can be worn to allow ambulation. Equinus, calcaneus, and mild positional clubfoot may respond to conservative management with passive manipulation. Surgical intervention may be warranted for more severe deformities (see 'Foot and ankle' above):

-Clubfoot deformities (picture 1) are often rigid, and most require surgical correction. Recurrence after surgery is common. (See 'Clubfoot' above.)

-Calcaneus is particularly common in patients with L4 to L5 level involvement (picture 2). It causes difficulty with bracing and shoe wear. It can be treated surgically with anterior or anterolateral soft-tissue release. (See 'Calcaneus' above.)

-Vertical talus (rocker bottom foot) (picture 3) usually requires surgical correction. (See 'Talus' above.)

-Cavovarus is characterized by an elevated longitudinal arch (cavus) and inverted heel (varus) (picture 4). When the cavovarus is rigid, it often causes skin breakdown, difficulty with bracing, and problems with ambulation. Surgery for cavovarus involves joint-sparing osteotomies with appropriate soft-tissue releases. Fusions should be avoided whenever possible.

-Ankle valgus (picture 5) can lead to skin irritation and breakdown over the medial malleolus due to excessive pressure against the orthosis. Surgical treatment depends on the anatomical location of the deformity. Treatment options for distal tibia valgus include medial hemiepiphysiodesis or, in severe cases, distal tibia osteotomy. For hindfoot valgus, treatment consists of a medial displacement osteotomy of the calcaneus. (See 'Valgus' above.)

●Patients with myelomeningocele have increased risks for wound infections, pathologic fractures, nonunion after orthopedic surgery, as well as latex allergy and skin breakdown. These considerations should inform surgical decision-making and routine care. (See 'Special considerations' above.)