Orthopedic management of myelomeningocele with a multidisciplinary approach: a systematic review of the literature

Background Myelomeningocele (MMC) is the most common and severe form of spina bifida and imposes a significant burden on patients and the healthcare system. Recently, the multidisciplinary management of MMC has become popular. Herein, we aimed to review the orthopedic management, outcomes, and complications of the of patients with MMC eyeing a multidisciplinary approach. Methods We searched PubMed and EMBASE to find relevant studies published before August 2020. All studies that included clinical management of MMC patients and published earlier than 2000 were considered for review on the condition that they reported at least one orthopedic intervention and the rate of complications. We excluded review articles, case reports, case series, letters, commentaries, editorials, and conference abstracts. The primary and secondary goals of our review were to report the outcomes and complication rates of multidisciplinary management for MMC patients. Results Twenty-six studies included data for the management of 229,791 patients with MMC and were selected. Sixteen studies reported multidisciplinary management in addition to orthopedic management. From those, 11 (42.31%) included urologic management, 13 (50%) neurosurgical management, 11 (42.31%) neurologic management, and 5 (19.23%) gastrointestinal management. All studies included postnatal operations and related management. No randomized clinical trial was found in our search. Conclusion Orthopedic approaches play a key role in MMC management by alleviating spinal deformities, particularly scoliosis, and hip, foot, and ankle complications. However, the most appropriate management, whether surgical or non-surgical, may vary for different patients, given disease severity and the age of patients. Graphical abstract


Background
Spina bifida (SB) represents a congenital cause of disability characterized by an opening in the vertebral column [1]. In 2004, this condition held the sixth place among various congenital birth defects resulting in hospital admission in the USA [2]. According to the registry of European Surveillance of Congenital Anomalies (EURO-CAT) in 2003-2007, the prevalence of SB was 0.51 per 1000 pregnancies, which makes it the most prevalent neural tube defect (NTD) [3]. Myelomeningocele (MMC), also known as open SB or SB aperta, is the most common and severe form of SB, inflicting a tremendous burden on patients and the healthcare system [4]. The responsible mechanism for this condition is the failure of neural tube closure during embryonic development, which results in a protruded spinal cord and meninges. This process leaves the underlying neural tissue vulnerable to damage [1,5]. MMC can be associated with other congenital disorders such as hydrocephalus and Chiari II malformation [5][6][7][8].
Orthopedic consequences may arise from MMC involving various parts of the body, including feet, spine, and hip [9,10]. Several orthopedic methods are used to manage these disabilities with variable success [11][12][13][14], and we will give a brief introduction regarding them in this "Background" section. Controversies regarding these methods are not addressed adequately and requires research and attention.
Foot consequences affect 80-95% of the patients and can present by clubfoot, valgus, equinus, calcaneus/calcaneovalgus, talus, etc. [15,16]. The Ponseti method of clubfoot, soft-tissue release, different types of osteotomy, and hemiepiphysiodesis for valgus are among the methods used to correct these abnormalities [16]. Skin complications, such as wound infection and pressure sores, osteomyelitis, delayed-union or non-union of the bones, loss of correction, avascular necrosis, and recurrence are among the complications that vary largely based on the condition and utilized technique [16][17][18][19].
Spinal surgery mostly involves correcting kyphosis, scoliosis, or lordosis. These consequences affect patients' appearance, ambulation, and quality of life by imposing consequences such as back pain and less social and personal acceptance [20,21]. Some of the surgical and nonsurgical management include spinal fusion, spinal orthoses, and sitting supports [13,22]. These treatments may cause several complications, including decreased ambulation, pressure sores and other infections, implant problems, neurologic consequences, and interference with other care such as self-catheterization [23][24][25].
Muscle paralysis and imbalance may result in hip deformities, such as dislocation, subluxation, or contracture [26]. Surgical reduction may benefit a small population of the patients based on their level of MMC, while preserving muscle strength and maintaining the pelvic level and motion may assist many others [27,28]. Surgical adverse effects include pathologic fractures and loss of ambulation [28,29].
Various other sequels may occur involving other organs depending on the level of MMC, including motor and sensory deficits, urological problems, and bowel incontinence [30][31][32][33][34]. Such complications may cause ambulation difficulties, diminished quality of life, and restriction of the patients' ability to attend school [34][35][36][37]. Managing these potentially unfavorable consequences require a multidisciplinary approach and highly specialized care.
In this systematic review, we summarize and compare the foremost treatment approaches proposed by researchers and specialists in the field of orthopedics, eyeing a multidisciplinary approach towards other fields.

Search strategy
This systematic review was conducted based on the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [38]. This review was registered (#CRD42021225916) in the International Prospective Register of Systematic Reviews (PROSPERO) and the review protocol can be accessed [39].
We included all studies that evaluated MMC patients' clinical management if they reported: (1) at least one type of orthopedic intervention, (2) the rates of complications, and (3) published earlier than 2000. We excluded review articles, case reports, case series, letters, commentaries, editorials, and conference abstracts.

Literature search and information sources
Before conducting this review, we searched PROSPERO and found no systematic review with a similar topic. To identify relevant publications, we searched PubMed and EMBASE databases in August 2020. Our search protocol was designed based on MeSH (MEDLINE) keywords and Emtree (EMBASE). The main search terms included MMC, spinal dysraphism, spina bifida, multidisciplinary management, and orthopedic management. The search was performed without time, country, or language limitations. The comprehensive search strategy is illustrated (Fig. 1).

Study selection and data collection
All resulting records were imported to EndNote (version X20, Thomson Reuters, Toronto, Ontario, Canada), and duplicates were removed. Two review authors (P.S. and A.K.) independently screened all titles and abstracts. Then, full texts of all potentially relevant publications were assessed for eligibility. To find additional records, we reviewed the reference lists of the included papers. Any discrepancies between the two reviewers were solved out via discussion and consensus. If the disagreement persisted, a third reviewer (S.M.) was consulted. The PRISMA study selection diagram is illustrated to show the study selection process (Fig. 2). Two authors (P.S. and A.K.) independently extracted data from the included studies. We designed a data extraction form which included the following items: (1) general information (name of the first author, publication year, location of study, and study title), (2) patients' characteristics (number of patients and controls, mean age, sex ratio, and location of MMC), (3) management methods, (4) rates of complications, and (5) outcome of interventions.

Outcome measures
In this review, the primary outcome was the result of orthopedic management for MMC patients. Besides, we summarized other accompanied managements (e.g., urologic, neurosurgical and neurological, gastrointestinal) to reach the purpose of conducting a multidisciplinary review. Additionally, we investigated the complications of these interventions.

Quality assessment
The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS) [40]. Based on this scale, each study can receive a score of 0-9 based on the quality of the sample selection (max 4 scores), comparability of cases and controls (max 2 scores), and assessment of the exposure/outcome (max 3 scores). In this quality assessment tool, a lower score indicates a greater risk of bias.
Moreover, all the studies included described postnatal operations and management. Table 1 presents the characteristics of the selected studies.

Quality assessment
We found no randomized clinical trial (RCT) regarding this topic. Therefore, the risk of bias was assessed with the NOS for non-randomized studies ( Table 2). We assessed the quality of 26 studies with a total of 234 items for the risk of bias. All studies received 3 or 4 points in the selection domain, except one study performed by Sponseller et al. [41]. The comparability was not adequately addressed in the majority of articles. Except for three studies [13,42,53], the exposure/outcome assessment was fully reported. Only two studies by Gerlach et al. and Wang et al. received a full score [46,50]. The lowest score was 5, which was attributed to Parsch et al. and Januschek et al. [13,53].

Orthopedic management
Patients often need diverse management approaches based on the affected part of the body, including the spine, foot, and hip [58].
Clubfoot Frischhut et al. [12] studied 91 patients with SB (182 feet). Clubfoot deformity was predominantly diagnosed in children with lumbar lesions (73 out of 182 feet). From the 37 feet corrected with surgery (via Cincinnati incision) before the age of 2 years, the recurrence of clubfoot deformity was observed in 29 feet by the age of 2, and 18 patients required a revision surgery by the age of 10. From the 73 cases associated with a lumbar lesion, bracing was used in 70 cases before the age of 2 and in 52 cases before the age of 10. At the last followup visit, at 24.5 years, only 2 cases needed revision surgery [12].
Valgus A valgus foot tends to be observed in mid and lower lumbar MMC, and hindfoot surgery is usually performed to correct this deformity [60]. Frischhut et al. reported 40 feet with calcaneo-valgus deformity (14 with L3-L4 lesions and 26 with L5-sacral lesions) at 10-year follow-up despite adequate treatment. Interestingly, this value increased to 48 (16 with L3-L4 lesions and 32 with L5-sacral lesions) at the last follow-up (24.5 years old on average) [12]. In the study of Torosian et al., postoperative outcomes showed that interventions had corrected the hindfoot alignment to approximately 5°of valgus. Also, the hindfoot alignment of feet varied from 0°to 10° [42].

Hip
Two studies attempted to manage hip instabilities surgically [14,26]. Erol [26]. Of the 16 patients with unilateral dislocation and functional problems, 14 experienced improvements in gait patterns, while the other did not show any improvement [26]. Yildirim et al. evaluated the periarticular release of contractures and bony procedures, with or without muscle transfer in two groups [14]. According to Reimer's radiographic index, the residual subluxation of the femoral head did not differ between the two groups. Despite the overall improvement of the pelvic obliquity, these two groups did not demonstrate any significant difference. The postoperative assessment showed that functional ambulatory remained similar to the preoperative status [26].

Urologic management
Moreover, they showed that urinary dysfunction and MMC level are not significantly correlated (p = 0.062). North et al. performed two 10-year cohorts and reported that 82% of patients in the first cohort and 94% of patients in the second cohort benefited from CIC to manage incontinency [55]. In the study from Ulsenheimer et al., seven patients required CIC based on the vesicourethral reflux or significant vesicle residues [44]. Anticholinergic medications was needed for seven patients. They also prescribed a combination of doxozym with oxybutynin for one patient and a combination of imypramine and oxybutynin for another one. Repeated urinary tract infections (UTI) episodes were reported in 10 patients. Also, they prescribed prophylactic antibiotics for all patients with neurogenic bladder [44].

Neurosurgical and neurological management
The follow-up assessments of kyphosis corrective surgery in the study of Ryabykh et al. showed improvement of modified Japanese Orthopedic Association (mJOA) neurologic scale by 0.6 points and the functional independence measure (FIM score) by 6.6 points, which represents average functional status [21]. None of the patients suffered from back pain (visual analog scale = 0). The requirement of ventriculoperitoneal (VP) shunt revision ranged from 30.5 to 86% in different studies [30,39,42,44]. In the study conducted by Ozerdemoglu et al., 16 out of the 26 MMC patients required a spinal fusion ultimately [43].

Gastrointestinal management
Bowel management in patients suffering from MMC consists of two main categories; enema and diapers. Two studies by Beuriat et al. [9,11] reported the rate of using enema as (34.78-24%) and diapers as (30.43-21%) published in 2018 and 2019, respectively. Applying suppositories, cecostomy tubes, digital sweeps, oral medication, diet control, and antegrade colonic enema (ACE) are other proposed management [55,57]. Spazzapan et al. used colostomy in 5.2% of patients to manage bowel incontinency [56].

Discussion
This review is the first to summarize outcomes and applications of various multidisciplinary orthopedic, urologic, neurologic, and gastrointestinal management of patients with MMC with an orthopedic focus. The orthopedic management of MMC tends to be based on musculoskeletal problems. MMC patients encounter congenital and acquired deformities, which can affect their quality of life. Congenital deformities include scoliosis, kyphosis, teratological hip dislocations, club feet, and flat feet with vertical talus. Collectively, for MMC patients with mild to moderate scoliosis (a flexible curve < 50°), non-operative treatment is suggested (e.g., sitting supports, spinal orthoses, and functional strengthening programs) to help them improve their independent functions [22,61]. However, for MMC patients with severe scoliosis, the treatment plan is based on whether they are ambulatory or not. Orthopedists mainly offer surgical treatment for nonambulatory patients who suffer from sitting or skin deformities due to spine curvature [25,62]. Regarding ambulatory patients, surgeons must decide case by case and consider the pros and cons of surgical intervention, mainly spinal fusion [25,62,63]. Possible complications are implant problems [64] (e.g., implant failure, dislocation, and pseudoarthrosis [25]) and wound infections [25].
Considering hip deformities, maintaining hip range of motion should be the orthopedist's treatment goal. Formerly, most hip surgical interventions were performed to reduce paralytic hip dislocations, but they were not successful in achieving the ability to ambulate, lessening the need for bracing, or relieving pain [27][28][29]65]. In contrast, currently, hip surgeries aim to release contractures. It is worth mentioning that treatment plan varies based on the level of myelomeningocele, whether sacral-level or thoracic and lumbar-level. Ultimately, surgeons should consider that maintaining a level pelvis and free motion of the hips rather than radiographic reduction of the hip are primary goals of the treatment plan [28]. Additionally, loss of motion and pathologic fractures are among surgical complications hindering ambulation [28,29].
As torsional abnormalities of the lower extremities often occur in MMC patients, it is essential to manage them if it interferes with their gait and ambulation. For non-ambulatory patients, orthopedic surgeon aims to minimize bracing requirements while achieving as normal a gait as possible. It is generally suggested to delay the surgery until the patient is 6 years old to decrease the risk of recurrence, and till then, orthotic management is helpful to maintain gait function [66]. Rotational osteotomy is the foremost choice of surgery in case of severity and difficulty with orthoses [67].
Regarding foot and ankle issues management, the orthopedist's treatment goal includes a plantigrade, flexible, braceable foot on which a shoe can be worn to allow ambulation. Conservative management with passive manipulation is mainly offered for MMC patients with equinus, calcaneus, and mild positional clubfoot.
For instance, severe clubfoot deformities may require surgical correction following the radical posteromediallateral release (PMLR) method, which leads to controversial outcomes due to the motor level of involvement [68]. Calcaneous feet treatment was reported following the anterior or anterolateral soft-tissue release with an 82% success rate [69]. Distal tibia valgus deformity could be corrected by 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 [18].
In children with MMC, orthoses are used to maintain alignment, prevent deformity, correct flexible deformities, facilitate independent mobility, and protect the insensate limb. Orthoses are used for upright weightbearing and mobility in thoracic and lumbar MMC patients. Due to absent hip extensors and abductors and ankle plantar-and dorsi-flexors, orthoses could help MMC patients with low lumbar and sacral level involvement s [70].
The majority of the included studies performed postnatal management and operations rather than prenatal. Although controversies exist between surgeons, postnatal repair is established as a worldwide standard for MMC patients [71]. Concurrently, the MOMS (the management of myelomeningocele study) has indicated that prenatal repair increased maternal and fetal complication risks. The outcomes were significantly better than postnatal repair in decreasing the need for VP shunt and hydrocephalus occurrence (40% vs. 82%), as well as functional improvement. The MOMS cohort assessed gait independence at the age of 30 months. As a result, more of the prenatal group had independent gait versus postnatal (40% vs. 21%) [72]. Prenatal repair of MMC is categorized as the neurosurgical management of MMC. We should consider the delivery method (cesarean section or vaginal delivery) to secure the neonate, neural tissues, and MMC sac [71]. However, Greene et al. reported no significant difference between the mode of delivery (cesarean and vaginal delivery) and patients' motor functions [73]. Regarding urological complications, MMC patients undergoing fetal (prenatal) surgery require neurogenic bladder management, similar to patients experiencing postnatal surgeries [74].
Ambulation status is one of the features taken into account for assessing the efficacy and effectiveness of the conducted procedures. The ambulation status is influenced by spasticity, contractures, syringohydromyelia, and musculoskeletal problems including, foot, knee, and hip deformities and scoliosis. Moreover, it has been suggested that the neurologic impairment level is a significant factor for ambulation. Although shunting is widely used as prenatal management, the history of shunt insertion or revision has a negative effect on ambulation status [75][76][77]. In the orthopedic field, surgeons correct spinal deformities to support muscle balance and sitting stability. Also, orthopedists can release hamstrings and treat knee flexion contractures in ambulatory patients. The valgus deformity can also affect ambulation due to muscle imbalance [78]. Although utilizing assistive devices may decrease the number of steps per day, it is a positive factor for predicting walking activity in MMC [79].
Shreds of evidence show that untethering the spinal cord prior to scoliosis surgery may be redundant in patients who do not characterize symptoms (e.g., pain, weakness, gait abnormality, lower extremity, hip and foot deformity, urological changes, and rapidly progressive scoliosis) [80].
Pediatric urologists' experience confirms that clean intermittent catheterization (CIC) may lessen renal deterioration risk. Moreover, in some cases, CIC might be influential on renal function improvement. The success rate of the CIC program hinges on several factors (e.g., physiological, developmental, motivational) [81].
The ultimate aim of management in MMC patients is to improve their quality of life. To assess the quality of life, there is a controversy regarding the person who should take the survey: the patients, their parents, or both. Studies measuring patients' health status with MMC have reported a lower health-related quality of life (HRQOL) than the general population [82][83][84][85]. On the other hand, exercise and fitness showed an essential impact on higher HRQOL [86]. Some studies have introduced predictors for HRQOL, including the need for support and an assistant to supervise them. In contrast, lesion level and social status had no significant effect on overall HRQOL [82]. Besides, managements like bladder augmentation increased patients' HRQOL by reducing the need for catheterization [87].
Despite all efforts for the management of MMC, it should be noted that lesser the time we waste, the better outcome we can achieve. Therefore, more equipped multidisciplinary centers should be established to give MMC patients the care and management they need and help them acquire a better quality of life. This approach brings together patients and specialists experienced in different disciplines. Moreover, the modern world has introduced robotic-assisted surgeries in the medical community, which could help surgeons accomplish better outcomes and reduce surgical complications. It is also suggested to conduct more studies on prenatal repair surgeries to compare their application, outcomes, and complications with postnatal repair surgeries.
This study encountered several limitations. We did not comprehensively review managements other than orthopedics due to the specific focus of our study. Included studies were mainly retrospective analyses rather than RCTs, which are critically needed to achieve more robust results. Another limitation of this study was that included studies did not have a homogeneous size of samples and surgery techniques. Further multivariate analyses are required to reveal each management's effects on MMC patients' HRQOL.

Conclusion
Timely and proper multidisciplinary management is critical for MMC given its high burden and psychosocial consequences. Orthopedic approaches play a key role in MMC management by alleviating spinal deformities, particularly scoliosis, and hip, foot, and ankle complications. However, the most appropriate management, whether surgical or non-surgical, may vary for different patients, given disease severity and the age of patients.