Reviewing the prognostic factors in myelomeningocele

OBJECTIVE

The goal of this study was to analyze the factors that have an impact on morbidity and mortality in patients with myelomeningocele (MMC).

METHODS

A retrospective cohort study was conducted to analyze factors associated with MMC that influence the morbidity and mortality of the disease. Data were collected from medical records of children who underwent the primary repair of MMC at the Fernandes Figueira Institute-Oswaldo Cruz Foundation (IFF-Fiocruz) between January 1995 and January 2015, with a minimum follow-up of 1 year. The following variables were analyzed: demographic characteristics (gestational age, sex, and birth weight); clinical features (head circumference at birth, anatomical and functional levels of MMC, hydrocephalus, symptomatic Chiari malformation type II, neurogenic bladder, and urinary tract infection [UTI]); and surgical details such as timing of repair of MMC, age at first shunt placement, shunt surgery modality (elective or emergency), concurrent surgery (correction of MMC and shunt insertion in the same surgical procedure), incidence and cause of shunt dysfunction, use of external ventricular drain, transfontanelle puncture, surgical wound complications prior to shunting, and endoscopic treatment of hydrocephalus.

RESULTS

A total of 231 patients with MMC were included in the analysis. Patients were followed for periods ranging from 1 to 20 years, with a mean of 6.9 years. The frequency of shunt placement was observed mainly among patients with MMC at the highest spinal levels (p < 0.01). The main causes of morbidity and mortality in patients with MMC were shunt failures, diagnosed in 91 of 193 cases (47.2%) of hydrocephalus, and repeated UTIs, in 129 of 231 cases (55.8%) of MMC; these were the main causes of hospitalization and death. Head circumference ≥ 38 cm at birth was found to be a significant risk factor for shunt revision (p < 0.001; 95% CI 1.092-1.354). Also, the lumbar functional level of MMC was associated with less revision than upper levels (p < 0.014; 95% CI 0.143-0.805). There was a significant association between recurrent UTI and thoracic functional level.

CONCLUSIONS

Macrocephaly at birth and higher levels of the defect have an impact on worse outcome and, therefore, are a challenge to the daily practice of pediatric neurosurgery.

Prenatal counseling for myelomeningocele in the era of fetal surgery: a shared decision-making approach

OBJECTIVE

The Management of Myelomeningocele Study demonstrated that fetal surgery, as compared to postnatal repair, decreases the rate of hydrocephalus and improves expected motor function. However, fetal surgery is associated with significant maternal and neonatal risks including uterine wall dehiscence, prematurity, and fetal or neonatal death. The goal of this study was to provide information about counseling expectant mothers regarding myelomeningocele in the era of fetal surgery.

METHODS

The authors conducted an extensive review of topics pertinent to counseling in the setting of myelomeningocele and introduce a new model for shared decision-making to aid practitioners during counseling.

RESULTS

Expectant mothers must decide in a timely manner among several potential options, namely termination of pregnancy, postnatal surgery, or fetal surgery. Multiple factors influence the decision, including maternal health, fetal heath, financial resources, social support, risk aversion, access to care, family planning, and values. In many cases, it is a difficult decision that benefits from the guidance of a pediatric neurosurgeon.

CONCLUSIONS

The authors review critical issues of prenatal counseling for myelomeningocele and discuss the process of shared decision-making as a framework to aid expectant mothers in choosing the treatment option best for them.

Fetal surgery for spina bifida

The two-hit hypothesis of neural injury in the wake of open neural tube defects suggests an opportunity for preservation of function and potential reversibility of early morphological changes in the fetus diagnosed with myelomeningocele. The Management of Myelomeningocele Study (MOMS) demonstrated reduced need for shunting and improved neurological function in patients treated in utero relative to postnatally, thereby offering level 1 evidence supporting fetal repair. Subsequent studies have offered additional information about urological, orthopedic, radiological, and maternal factors surrounding fetal repair. The quest for robust long-term neurocognitive and motor function data is underway and poised to shape the future of fetal repair. In addition, technical innovations such as fetoscopic surgery aim to minimize maternal morbidity while conferring the beneficial effects observed with open intrauterine intervention.

Twenty years' experience with myelomeningocele management at a single institution: lessons learned

OBJECTIVE

The authors reviewed 20 years' experience with the surgical management of open myelomeningocele in a well-defined retrospective cohort from a single large academic medical center. Their goal was to define the characteristics of a modern cohort of children with myelomeningocele to allow for evidence-based decision-making for the treatment of these patients.

METHODS

After IRB approval was obtained, the authors queried an operative database maintained by the Department of Neurological Surgery at Children's Hospital of Pittsburgh for patients who underwent closure of a myelomeningocele between 1995 and 2015. They identified 153 infants, and a retrospective chart review was performed.

RESULTS

Eighty-eight percent of the patients required placement of a ventriculoperitoneal shunt, and 15% of these patients acquired shunt-related infections. Eighteen percent of patients underwent Chiari malformation type II (CM-II) decompression. Sixteen percent of patients underwent a tethered cord release. Three percent of patients died within the 1st year of life. Predictors of an early demise included poor Apgar scores, large head circumference, and need for early CM-II decompression. Functional motor outcome was slightly better than predicted by anatomical level of defect.

CONCLUSIONS

Myelomeningoceles represent a severe birth defect with life-threatening complications. The authors provide long-term follow-up data and insight into factors that contribute to early death.

Syringobulbia in pediatric patients with Chiari malformation type I

OBJECTIVE Syringobulbia (SB) is a rare entity, with few cases associated with Chiari malformation type I (CM-I) in the pediatric population. The authors reviewed all pediatric cases of CM-I-associated SB managed at their institution in order to better understand the presentation, treatment, and surgical outcomes of this condition. METHODS A prospectively maintained institutional database of craniovertebral junction abnormalities was analyzed to identify all cases of CM-I and SB from the MRI era (i.e., after 1984). The authors recorded presenting symptoms, physical examination findings, radiological findings, surgical treatment strategy, intraoperative findings, and outcomes. SB cases associated with tumors, infections, or type II Chiari malformations were excluded. RESULTS The authors identified 326 pediatric patients with CM-I who were surgically treated. SB was identified in 13 (4%) of these 326 patients. Headache and neck pain were noted in all 13 cases. Cranial nerve abnormalities were common: vagus and glossopharyngeal nerve dysfunction was the most frequent observation. Other cranial nerves affected included the trigeminal, abducens, and hypoglossal nerves. Several patients exhibited multiple cranial nerve palsies at presentation. Central sleep apnea was present in 6 patients. Syringomyelia (SM) was present in all 13 patients. SB involved the medulla in all cases, and extended rostrally into the pons and midbrain in 2 patients; in 1 of these 2 cases the cavity extended further rostrally to the cerebrum (syringocephaly). SB communicated with the fourth ventricle in 7 of the 13 cases. All 13 patients were treated with posterior fossa decompression with intradural exploration to ensure CSF egress out of the fourth ventricle and through the foramen magnum. The foramen of Magendie was found to be occluded by an arachnoid veil in 9 cases. Follow-up evaluation revealed that SB improved before SM. Cranial nerve palsies regressed in 11 of the 13 patients, and SB improved in all 13. CONCLUSIONS The incidence of SB in our surgical series of pediatric patients with CM-I was 4%, and all of these patients had accompanying SM. The SB cavity involved the medulla in all cases and was found to communicate with the fourth ventricle in 54% of cases. Posterior fossa decompression with intradural exploration and duraplasty is an effective treatment for these patients.

Predictors of mortality in children with myelomeningocele and symptomatic Chiari type II malformation

OBJECTIVE Chiari malformation type II (CM-II) in myelomeningocele is associated with a significant rate of mortality and poor outcome. Death is frequently heralded by the onset or progression of neurological symptoms. The authors sought to identify predictors of poor outcome and mortality within the myelomeningocele population at Children's Hospital of Pittsburgh. METHODS A retrospective chart and radiology review was performed on all infants who underwent primary closure of a myelomeningocele defect at Children's Hospital of Pittsburgh between the years of 1995 and 2015. Preoperative symptoms and signs leading to CM-II decompression, as well as operative details and postoperative changes in these symptoms and signs, were investigated in detail and correlated to outcome. Poor outcome was defined as death, stridor, or ventilator dependence. Deceased patients were separately assessed within this subgroup. RESULTS Thirty-two (21%) of 153 patients were found to have symptomatic CM-II. Of the 32 patients meeting inclusion criteria, 12 (38%) had poor outcomes. Eight patients (25%) died since initial presentation; 5 of these patients (16% of the overall cohort) died within the 1st year of life and 3 (9%) died during adolescence. Seven (88%) of the 8 patients who died had central apnea on presentation (p = 0.001) and 7 (44%) of the 16 patients who developed symptoms in the first 3 months of life died, compared with 1 (6.3%) of 16 who developed symptoms later in childhood (p = 0.04). The median Apgar score at 1 minute was 4.5 for patients who died and 8 for surviving patients (p = 0.006). The median diameter of the myelomeningocele defect was 5.75 cm for patients who died and 5 for those who survived (p = 0.01). The anatomical level of defect trended toward higher levels in patients who died, with 4 patients in that group having an anatomical level at L-2 or higher compared with 5 of the surviving patients (p = 0.001). The median initial head circumference for the 5 patients dying in the 1st year of life was 41.5 cm, versus 34 cm for all other patients (p = 0.01). CONCLUSIONS CM-II in spina bifida is associated with a significant mortality rate even when surgical intervention is performed. Death is more frequent in symptomatic patients presenting prior to 1 year of age. Late deaths are associated with symptom progression despite aggressive surgical and medical intervention. In this patient cohort, death was more likely in patients with symptomatic presentation during the first 3 months of life, low Apgar scores, large myelomeningocele defects, early central apnea, and large head circumference at birth.