Neural tube defects are the most common congenital anomaly of the central nervous system . Meningomyelocele is the most common anomaly among NTD defects. While the incidence of meningomyelocele in developed countries is gradually decreasing, it is still an important health problem in developing countries. Postnatal management of MMC is discussed with parents of patients who have antenatal diagnosis in developed countries and 60-70% of them decide to terminate pregnancy . Only 22% of our patients had antenatal diagnosis. None of the families diagnosed with antenatal diagnosis approved the decision of termination of pregnancy, due to anti-abortion socio-cultural and religious reasons.
The current approach to the timing of MMC surgical repair is in favor of early surgery [14,15]. However, it is necessary to have an appropriate time interval to obtain comprehensive information about the patient's clinical condition and to plan surgical reconstruction adequately. Prenatal diagnosis, detailed examination and delivery of MMC patients in centers where early surgery can be performed is ideal. Approximately one quarter of our patients (10 patients) were born in an external center and were referred to our hospital.
Cases with hydrocephalus constitute approximately 85-90% of patients with MMC [16,17] . In our study, the number of MM patients who had accompanying hydrocephalus was 24 (58.5%). In 15% of cases accompanied by hydrocephalus at birth, signs of increased intracranial pressure (vomiting, dehiscence, sun-setting eyes, stretched fontanel) or brain stem dysfunction (apnea, sucking-swallowing disorder) may be observed . Chiari II malformation is common, especially in patients with brain stem dysfunction and urgent treatment is required. In patients with NTD, VPS (ventriculoperitoneal shunt) is needed to prevent neurocognitive and motor dysfunction caused by the accompanying Chiari II malformation and hydrocephalus . Therefore, at least 80% of patients with NTD require VPS . The timing of treatment of hydrocephalus accompanying MMC is still controversial due to factors such as infection, intellectual development and shunt dysfunction. Early shunt placement has been reported to improve rapid intracranial pressure in the presence of severe hydrocephalus and to improve wound healing faster in the MMC repaired area, also shortening hospital stay, preventing CSF leakage and protecting the brain from progressive ventricular dilatation 16,20]. It is contemplated that shunt placement time may affect the rate of shunt infection, and that shunt placement reverses the flow of cerebrospinal fluid and allows fluid from the lumbar region to travel to the ventricles to facilitate infection. Therefore, infective complications were observed more frequently in patients with simultaneous shunt placement with MMC repair than those with late shunt placement . Oktem et al. reported that VP shunt placement after MMC repair reduces wound infection, CSF leakage, and shunt infection in patients, in their study comparing VP shunt placement in the same and different sessions with MMC repair . The approach to treating hydrocephalus days or weeks after MMC surgical repair is more often preferred. The number of patients requiring VPS placement in our study was 22 (53.7%). According to the literature, our hydrocephalus rate was lower. In our study, 13 (31.7%) patients had simultaneous VPS and 9 (21.9%) patients had late VPS; there was no statistical difference between the groups in terms of the number of patients requiring VPS. Early VPS placement was performed in patients with symptoms of symptomatic hydrocephalus and brain stem dysfunction (sucking swallowing disorder, apnea).
In our study, of the patients who developed surgical complications, 8 (44.4%) patients were in the early surgery group and 7 (30.4%) patients were in the late surgery group. CNS infections (ventriculitis and meningitis) were observed in 3 (7.3%) patients. In the literature, ventriculitis and meningitis independent of shunt infection have been reported as 4-12.5% in MMC patients [23,24,25]. Ventriculitis and meningitis complications were observed in 7.3% of our patients.
The most common site of MMC is lumbar with 60-70% [25,26]. In our study, 26.8% of the localizations where MMC was seen were in the lumbar region, and together with the lumbosacral region, it made up 60.9% of the cases.
The debate about the optimal time for MMC repair has gained a new dimension with the increasing experience of intrauterine surgery. Since 1997, experimental procedures for prenatal repair of MMC have begun to increase the experience of fetal surgery [28 . Approximately 80% of NTDs require VPS in the postnatal period in order to prevent the destruction of hydrocephalus on brain tissue and to prevent deterioration of neurocognitive development . Prenatal surgery provides significant improvement in hindbrain herniation and reduces the risk of Chiari II malformation. In initial studies, prenatal surgery was shown to reduce the need for VPS by 50% in the first year . Tulipan et al. showed that they reduced the risk of hydrocephalus significantly (85.7% control vs. 54.8% study group) with prenatal surgery performed at 25 weeks of gestation or less, when compared to the traditional method . The safety and efficacy of intrauterine surgery were evaluated in a randomized controlled MOMS (Management of Myelomeningocele Study) study comparing prenatal and postnatal surgery. In this large multicenter study, intrauterine surgery reduced shunt requirement and improved motor outcomes at 30 months but was associated with maternal and fetal risks like preterm delivery and uterine dehiscence at delivery . Intrauterine MMC surgery continues to be performed in experienced centers. Postnatal traditional surgery is widely performed all over the world.
Early aggressive treatment approach in postnatal MMC surgery reduces early morbidity and mortality rates . Oncel et al. demonstrated that early surgery (<5 days) shortened hospital stay and antibiotic treatment time and reduced complication rates . In the long term, it is reported that cognitive functions are better, need for long-term care and incidence of urinary incontinence are reduced and it positively affects neurogenic bladder prognosis and thus urinary tract function [33,34,35]. Preoperative rupture of MMC, postoperative dehiscence, and incidence of neurodevelopmental retardation 1 year after delivery showed improved outcome after immediate surgical intervention after birth (mean time of surgery after birth 1 h 30 min) . In our study, although there was a shorter duration of hospital stay and antibiotic treatment in the early surgery group, there was no statistical difference. The number of prenatally diagnosed patients in the early surgery group was higher than those in the late surgery group. There were no significant differences between the groups in terms of the number of patients who developed surgical complications and total complications. In our study, we believe the fact that all patients who developed preop MMC sac rupture being in the early surgery group (<3 days) was important in terms of not showing significant difference between the early and late surgery groups. In addition, low hydrocephalus rate in our cases is one of the factors that cause no difference in prognosis. The fact that the number of patients who were reoperated except for VPS placement after primary surgery is low in both groups is the reason that there is no difference in prognosis.
Our study had many limitations. Most importantly, the number of patients included in the study was limited, it was retrospective, and a single-center study. The inclusion of a single center in the study was an advantage as perioperative interventions and treatments were standard. In our study, we were able to evaluate short-term results. One of the major limitations of the study was the lack of evaluation of the long-term outcome of a clinical condition, especially for MMC which is a major cause of lifelong morbidity.
In conclusion, surgical timing of MMC remains important considering the morbidity risks. National policy on prenatal follow-up of pregnancy and folic acid supplementation should be formulated and implemented to prevent NTD development. In countries where MMC is frequently observed, intrauterine surgery is not yet widespread. We believe that in addition to postnatal surgery timing, preoperative sac rupture, VPS placement time and accompanying anomalies (such as hydrocephalus) are the predictors of MMC prognosis.