Pediatrics.

Abstract

The specialty of pediatric neurosurgery requires an intimate knowledge of embryology, genetics, physiology, and nervous system development. Physical examination and surgical techniques vary with patient's age, and additional attention is given to social circumstances because the patients are without autonomy. Congenital disorders that are present at birth, ie, myelomeningocele and hydrocephalus, may present with distinct diagnostic challenges as the body matures. Operations such as spinal fusion, when it is done in toddlerhood vs teenage years, require different preparations and postoperative follow-ups. It is for these reasons, among others, that an additional year of fellowship training is required upon completion of neurosurgical residency to practice pediatric neurosurgery in the United States. The topics covered in this section are not meant to be comprehensive. The treatment of hydrocephalus, either with cerebrospinal fluid (CSF) shunts or other diversion methods, are practiced by adult and pediatric neurosurgeons alike. These operations typically made up 20% to 40% of case volumes in a pediatric neurosurgical service. Operations for craniosynostosis, encephalocele, and myelomeningocele are done almost exclusively in children. They are good examples of how neurosurgical treatments have evolved over time with technological advancements and a deeper understanding of disease pathophysiology. In the subsection on skull fracture, a by and large nonoperative entity, readers’ attention is directed to issues that are nonetheless neurosurgical: concussion management, discernment of child abuse, and the need for longer term follow-up compared to that offered to an adult patient population. For a comprehensive coverage of these topics and others, the medical students may refer Principles and Practice of Pediatric Neurosurgery or other textbooks. CHAPTER 1: COMMUNICATING AND NONCOMMUNICATING HYDROCEPHALUS Case Presentation A 16-yr-old female with no previous past medical history presents with 2 wk of progressive headaches, nausea, and vomiting. Her exam is significant for moderate papilledema. Imaging demonstrated ventriculomegaly of the lateral and third ventricles with transependymal flow and convexity sulcal effacement. Sagittal imaging demonstrated a web in the cerebral aqueduct (Figure 1).FIGURE 1.: Axial and sagittal T2-weighted MRI demonstrating obstructive hydrocephalus from a web in the cerebral aqueduct and the associated typical MRI findings.Questions What are the most common presenting symptoms of hydrocephalus in infants and children? Infant: Headache; Children: Restricted Upgaze Infant: Increasing head circumference; Children: Restricted Upgaze Infant: Bulging fontanelle; Children: Irritability Infant: Increasing head circumference; Children: Irritability Infant: Bulging fontanelle; Children: Nausea/Vomiting What is the leading cause of hydrocephalus in infants in the United States? Spina bifida Aqueductal stenosis Hemorrhage Infection Trauma What is the most common complication of ventriculoperitoneal (VP) shunting? Infection Seizure Symptomatic hemorrhage Shunt failure Short-term memory loss What is the most common complication of endoscopic third ventriculostomy (ETV)? Basilar artery injury Short-term memory loss Failure of ETV Endocrine abnormality Infection Which patient below carries the highest likelihood for third ventriculostomy success? 1-mo-old posthemorrhagic 1-yr-old postinfectious 1-yr-old myelomeningocele 10-yr-old post-traumatic 10-yr-old tectal glioma Introduction Hydrocephalus is derived from the Greek words “hudro” meaning water and “kephale” meaning head. In the most basic understanding, hydrocephalus is an increase in CSF within the central nervous system (CNS) resulting in increased intracranial pressure (ICP) from (1) an obstruction of CSF flow or (2) either increased production or impaired absorption. While a number of different classification systems are used, communicating versus noncommunicating are the terms most commonly discussed in clinical practice. “Noncommunicating” hydrocephalus implies that CSF flow out of the ventricular system to the subarachnoid space is impaired or obstructed. The term communicating denotes impaired absorption at a point after CSF reaches the subarachnoid space. Additional terms include hydrocephalus ex vacuo describing enlargement of CSF fluid spaces due to brain atrophy without an increase in ICP, and normal pressure hydrocephalus, a condition with enlarged CSF spaces but normal ICP on testing. Epidemiology and Causes Pediatric hydrocephalus is the most common treated neurosurgical problem in infants and children; however, recent studies demonstrate an overall declining incidence. The current estimated incidence ranges from 1 in every 500 to 1000 children. The decreasing incidence is likely related to a number of factors including: improved prenatal care and education, a decline in the incidence of spina bifida and preterm infants, and improved perinatal and prematurity care. Common causes of infantile and pediatric hydrocephalus include congenital and genetic hydrocephalus, myelomeningocele associated hydrocephalus, posthemorrhagic hydrocephalus, postinfection hydrocephalus, noncommunicating hydrocephalus secondary to mass lesions, and post-traumatic hydrocephalus. Currently, intraventricular hemorrhage (IVH) is the leading cause of infantile hydrocephalus. Clinical Presentation The majority of children with hydrocephalus present at birth or shortly thereafter, but in pediatrics symptoms vary by age due the presence of open cranial sutures. The Monro-Kellie doctrine describes the relationship between ICP and the volume of intracranial components. After the cranial sutures and fontanelle are closed, patients’ symptoms are more closely related to elevated ICP. However, at birth when the cranial sutures are still open, infants more commonly present with increasing head circumference. Table 1 summarizes the most common presenting symptoms of hydrocephalus for infants and children. TABLE 1. - Clinical Presentation of Hydrocephalus Infants Children Increasing head circumference: 81% Irritability: 27% Bulging fontanelle: 71% Delayed milestones: 20% Delayed milestones: 21% Nausea/vomiting: 19% Loss of upward gaze: 16% Headache: 18% Lethargy: 13% Lethargy: 18% Focal neurological deficits: 12% New seizures/change in seizure pattern: 7% Treatment Options Pediatric hydrocephalus treatment options vary based on the cause and acuity of presentation. For premature infants, many cases require surgical temporizing methods while the patient awaits a more definitive and permanent treatment. Temporizing methods include lumbar punctures, fontanelle taps, external ventricular drains (EVDs), ventricular access devices, and ventricular to subgaleal shunts (VSGS). VSGS shunts may reduce the need for permanent shunt placement in some patients, and they do not require frequent access for CSF aspiration. Ventricular access devices do require percutaneous access for CSF aspiration but are reported to have a lower morbidity and mortality than EVDs and similar outcomes to VSGS. Generally, each temporizing method may play a role in the treatment of hydrocephalus depending on the clinical setting and surgeons experience with the technique. Permanent surgical solutions to hydrocephalus include CSF shunting and ETV without and with choroid plexus coagulation (CPC). A shunt is a permanent CSF diversion device with 3 components: a ventricular catheter, a valve, and a distal catheter. In 1949, Nulsen and Spitz implanted the first shunt system. Since that time there have been many advances in shunt components including the development of programmable valves. Currently, there is insufficient evidence to suggest superiority of 1 system over another; both programmable valves and fixed (nonprogrammable) systems have demonstrated efficacy in selected patients. Advances in materials for catheters include silicone elastomer, plus the addition of antibiotic impregnation, which has demonstrated a lower shunt infection rates. The preferred method of shunting remains VP shunting, but other common distal locations include pleural and atrial. Alternatives to shunting include ETV and ETV with choroid plexus cauterization. ETV success is higher in cases of noncommunicative hydrocephalus. This procedure is performed with the assistance of an endoscope. The lateral ventricle is entered and the endoscope is driven into the third ventricle through the foramen of Monro. Then an opening is made through the tuber cinereum in the floor of the third ventricle creating an alternative pathway for CSF flow (Figures 2 and 3). A score for determining the percentage of success of ETV based on the age, etiology, and the presence of a previous shunt has been developed and validated (Table 2). The addition of CPC to ETV has been reported to improve the success of the ETV in preventing the need for a shunt. The reported efficacy at this time, however, appears to be lower in developed nations suggesting the need for additional long-term prospective trials in comparison with shunting to optimize patient outcomes.FIGURE 2.: Demonstration of endoscopic view of the lateral ventricle. Note the relationship of the choroid plexus medial to the thalamostriate vein. The third ventricle is entered through the Foramen of Monro.FIGURE 3.: Demonstration of the floor of the third ventricle: (1) marks the tuber cinereum anterior to the mammillary body (2); (3) marks the infundibular recess/pituitary stalk. TABLE 2. - ETV Success Score—Sum of Points = Percentage Probability of ETV Success at 6 mo Postoperative Score Age Etiology Previous Shunt 0 <1 mo Postinfectious Previous shunt 10 1- 6 mo No previous shunt 20 Myelomeningocele IVH Nontectal brain tumor 30 6 mo to 1 yr Aqueductal stenosis Tectal tumor/lesion 40 1-10 yr 50 >/=10 yr Both treatment options (CSF shunt and ETV) carry risks and complications, which are summarized in Table 3. The biggest risk for both procedures is failure or occlusion, with both surgeries having similar failure rates for noncommunicating hydrocephalus. Both treatment options (CSF shunt and ETV) carry risks and complications, which are summarized in Table 3. The biggest risk for both procedures is failure or occlusion, with both surgeries having similar failure rates for noncommunicating hydrocephalus. ETV has a more favorable adverse event profile and a much lower rate of CSF infection. Most pediatric neurosurgeons are eager to use therapies that avoid the need for placement of a shunt. TABLE 3. - Reported Complications of CSF Shunting and ETV Shunt Complications Rate/Comment ETV Complications Rate/Comment Blockage/Failure 38%/1 yr Blockage/Failure 30%/1 yr 50%/2 yr 40%/2 yr (5%/yr after) (3%/yr after) Infection Overall 10% Infection Overall ∼1%-2% 20% preterm infant Breakage, disconnection ∼ 5% Increases with age of shunt Bleeding/hemorrhage Overall—2%-4% Basilar injury <0.5% Abdominal cyst, pleural effusion, Atrial thrombus Distal complications ∼30%-40% Neurological injury/memory loss <2% Slit ventricle Syndrome Symptomatic < 10% Enocrinologic irregularities <1% Case Discussion This patient presented with noncommunicating (obstructive) hydrocephalus with the blockage of CSF flow at the level of the cerebral aqueduct. Permanent treatment of hydrocephalus was accomplished with an ETV. Figure 4 demonstrates the postoperative magnetic resonance imaging (MRI) findings.FIGURE 4.: Axial and sagittal T2-weighted MRI demonstrating mildly decreased ventricle size and significantly improved CSF sulcal pattern following ETV. There is also flow turbulence (arrow) through the ostomy in the tuber cinereum. Frequently, the ventricles do not dramatically decrease in size following a successful ETV, particularly in cases of long-standing hydrocephalus.Answers D. Prior to the fusion of cranial sutures, infants most commonly present subacutely with increasing head circumference. Children typically become irritable before progressing to vomiting or restricted upgaze. C. Posthemorrhagic hydrocephalus associated with prematurity is the most common underlying etiology for shunting in US. D. Shunt blockage may occur up to 30% to 40% within the first year after shunt insertion. Infection occurs in about 8% of shunt procedures. Hemorrhage occurs in approximately 4% but is rarely symptomatic. Seizure and memory loss occur in <1%. C. The failure rate of ETV is similar to a VPS for the first year, then is less likely to fail subsequently. Occurrences of serious complications with ETV are possible, but infrequent. Basilar artery injury occurs in approximately 1%. E. Please refer to the ETV success score table. Pearls ✓ Hydrocephalus is one of the most common disorders that adult and pediatric neurosurgeons treat ✓ Many types of hydrocephalus can be successfully treated without inserting a VP shunt ✓ Despite advances in shunt hardware including antibiotic-impregnated tubing, shunt infection remains an extraordinarily common morbid and costly complication SUGGESTED READING Bouras T, Sgouros S. Complications of endoscopic third ventriculostomy. J Neurosurg Pediatr. 2011;7(6):643-649. Drake JM, Kestle JR, Milner R, et al. Randomized trial of cerebrospinal fluid shunt valve design in pediatric hydrocephalus. Neurosurgery. 1998;43(2):294-303; discussion 303-305. Govender ST, Nathoo N, van Dellen JR. Evaluation of an antibiotic-impregnated shunt system for the treatment of hydrocephalus. J Neurosurg. 2003;99(5):831-839. Kulkarni AV, Drake JM, Kestle JR, et al. Predicting who will benefit from endoscopic third ventriculostomy compared with shunt insertion in childhood hydrocephalus using the ETV Success Score. J Neurosurg Pediatr2010;6(4):310-315. Stone SS, Warf BC. Combined endoscopic third ventriculostomy and choroid plexus cauterization as primary treatment for infant hydrocephalus: a prospective North American series. J Neurosurg Pediatr. 2014;14(5):439-446. Whitehead WE, Riva-Cambrin J, Kulkarni AV, et al. Ventricular catheter entry site and not catheter tip location predicts shunt survival: a secondary analysis of 3 large pediatric hydrocephalus studies. J Neurosurg Pediatr. 2017;19(2):157-167. Abou-Hamden A, Drake JM. Hydrocephalus. In: Principles of Pediatric Neurosurgery. 3rd ed. New York, NY: Thieme;2015. CHAPTER 2: MYELOMENINGOCELE Case Presentation A 36-yr-old pregnant woman was referred for prenatal neurosurgical consultation after a routine 20-wk screening ultrasound identified a “lemon sign,” “banana sign,” (Figure 5), as well as a possible neural tube defect (NTD). She has 2 healthy children born at full term via normal spontaneous vaginal delivery without perinatal complication, and there is no family history of congenital anomalies. The same day, prior to consultation, she underwent a fetal MRI (Figure 6). This demonstrates severe ventriculomegaly with an atrial diameter (AD) of 15 mm bilaterally, Chiari 2 malformation, and an open NTD consistent with myelomeningocele beginning at L3.FIGURE 5.: Axial 20-wk ultrasound of the fetal head. Note the convex appearance of the frontal bones (“lemon sign”), and the “banana sign” of the posterior fossa due to Chiari 2 malformation (arrows).FIGURE 6.: Fetal MRI. A, Sagittal T2 image demonstrating the myelomeningocele at L3 and Chiari 2 malformation (arrows). B, Axial T2 weighted image of the brain demonstrating ventriculomegaly with an AD of 15 mm (line). C, Axial T2 weighted image through the lumbar spine demonstrating the open spinal canal (arrow).Questions What is the approximate prevalence of open NTDs in the US? 1/500 live births 1/1000 live births 1/5000 live births 1/20 000 live births Open NTDs occur at what stage of embryonic development? gastrulation primary neurulation secondary neurulation any of the above What treatment options are available to the family? postnatal closure fetal surgery termination all of the above With an L3 motor level, what is the last intact motor group and the likelihood of long-term community ambulation? knee extension; 20% foot dorsiflexion; 70% hip abduction; 40% extensor hallucis longus; 80% If the patient and family elect fetal surgery, what is the likelihood of hydrocephalus given an AD of 15 mm? 20% 45% 79% 88% Epidemiology Myelomeningocele is the most common open NTD, and the most common congenital anomaly of the CNS. It is associated with a high rate of neurogenic bladder and bowel, lower extremity weakness, sensory loss, and deformity that varies depending on the spinal level, brainstem dysfunction due to Chiari 2 malformation, and a high rate of hydrocephalus. Worldwide, the prevalence of open NTDs range between 1 and 10 out of every 10 000 live births. In the United States, the prevalence is approximately 2/10 000 live births. It is widely known that diet supplementation with folic acid in women of child bearing age can reduce the prevalence of myelomeningocele. A clinical trial published in 1992 randomized 4753 women with no history of previous pregnancy complicated by NTD to receive either 12 vitamins including 0.8 mg of folic acid daily, or trace elements. There was a significant reduction in both NTD (0 vs 6) and overall congenital anomalies in children born to women in the treatment group. Supplementation with folic acid reduces the risk of NTD by 70%, and folic acid combined with vitamin B12 may reduce the risk by 90%. In 1998, all cereal grain products in the US were fortified with folic acid, adding 0.1 mg to the average diet. This was associated with a 26% reduction in the prevalence of NTD. Embryology Myelomeningocele is a disorder of primary neurulation, one of the earliest steps in embryogenesis. Primary neurulation occurs immediately following gastrulation, or the formation of a 3-layer embryo. During gastrulation, epiblast cells migrate toward the primitive streak to form the mesoderm and endoderm. Migrating epiblast cells closest to Hensen's node form the notochord. Sixteen days after ovulation, these cells induce the overlying neuroectoderm to become a pseudostratified epithelium that forms the neural plate, the first step of primary neurulation. The neural plate is continuous laterally with the squamous epithelium that forms the cutaneous ectoderm. By 19 d, the neural plate develops dorsolateral and medial hinge points and becomes the neural groove. By 21 d, the neural groove deepens, and the neural folds elevate. Finally, the neural tube is formed as the cutaneous ectoderm fuses over the developing neural tube. The neuroepithelium then fuses and dysjunction from the cutaneous ectoderm occurs, separating the CNS from the skin. The posterior neuropore typically closes around the 28th day postovulation. Failure of fusion and dysjunction (ie, nondysjunction) of the posterior neuropore of the neural tube leads to myelomeningocele. Surgical Treatment Although many obstetricians opt for delivery via cesarean section for infants with myelomeningocele, limited evidence has failed to demonstrate a difference in neurological outcome between cesarean and vaginal delivery. Traditionally, surgical closure of myelomeningocele is performed in the first 72 h of life to decrease the risk of meningitis (Figure 7; Video). While there is considerable variation in surgical technique, the surgical principles include dissection of the transitional arachnoid from the skin the release the neural placode, dissection of the epidural plane containing fat from the skin, primary closure of the dura and skin. Before dural closure, the neural placode may be imbricated into a closed neural tube to bring pial edges together. Often, a myofascial flap is dissected and closed over the dura. Larger defects may require plastic surgery to perform rotational flaps to achieve closure without tension. {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video.","caption":"Step-by-step guide for closure of lumber myelomeningocele. This video can be accessed in the HTML version of the article. Please visit www.operativeneurosurgery-online.com to view this article in HTML and play the video.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_xoa0q1zi"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} FIGURE 7.: Typical appearance of myelomeningocele at birth prior to surgical repair. A, Infant head is to the left; CSF can be seen leaking from the open defect. B, High-magnification view demonstrating the neural placode (open neural tube), transitional zone (arachnoid membrane adherent to the skin), and dysplastic epithelium.Fetal surgery for myelomeningocele (Figure 8) was conceptualized based on the 2-hit hypothesis advanced by Dr Heffez in 1990. This suggested that while some degree of neurological dysfunction was due to the anomaly itself, mechanical trauma from movement of the fetus and chemical injury from amniotic fluid compound neurological dysfunction. Experiments in sheep models demonstrated the Chiari 2 malformation, hind limb weakness, and incontinence could be rescued with prenatal closure. Published in 2011, the MOMS trial was a multicenter randomized controlled trial comparing fetal surgery between 19 and 25 and 6/7 wk gestation to postnatal surgery for myelomeningocele associated with Chiari 2 malformation. The primary outcome measures were a composite of death and need for CSF shunt placement at 12 mo of age, and independent ambulation at 30 mo of age. The trial was stopped early after interim analysis demonstrated a clear benefit to fetal surgery for both primary outcomes. At 12 mo of life, 65% of patients randomized to fetal surgery met criteria for a CSF shunt, compared to 92% of patients randomized to postnatal surgery. Similarly, 42% of patients treated with fetal surgery were walking independently at 30 mo, compared to 21% of patients treated with postnatal closure.FIGURE 8.: Fetal surgery for myelomeningocele repair at 24 wk. A, Exposure of the fetal defect after open hysterotomy. B, Dissection and primary closure.The results of the MOMS trial have led to an increase in fetal surgery for closure of myelomeningocele. However, this is not without risk: a significantly higher rate of prematurity and related complications occurred in the fetal surgery group of the MOMS trial. In addition, wound dehiscence of the hysterotomy site was common, with as-yet unknown long-term effects on future pregnancies. There are many maternal and fetal exclusion criteria specified in the MOMS trial, and the NIH recommends all centers performing fetal surgery continue to adhere to these criteria. Finally, fetal surgery is not a cure. While there was a 27% absolute risk reduction in meeting criteria for hydrocephalus and CSF shunt placement, 65% of fetal surgery patients still met criteria. The same is true of ambulation: although twice as many children treated with fetal surgery were walking at 30 mo without assistance, 58% of children in the fetal surgery group still required assistance. Previous long-term studies of patients with myelomeningocele have demonstrated that lesions below L3 are associated with an 80% long-term ambulation rate, whereas only 20% of patients with lesions at L3 and above ambulate outside the home. So, a patient with an L3 level may benefit from fetal surgery by crossing this important functional threshold. Conversely, a patient with an L1 lesion is still unlikely to achieve ambulation with fetal surgery, and a patient with an S1 lesion would be expected to ambulate regardless of the timing of surgery. Recently, the entire cohort of patients enrolled in the MOMS trial was analyzed for the need for CSF diversion according to ventricle size (AD) on the screening fetal MRI. For patients without ventriculomegaly at the time of screening (AD < 10 mm), the risk of hydrocephalus was 20% with fetal surgery compared to 79.4% with postnatal closure. For patients with mild ventriculomegaly (AD 10-14 mm), the risk was 45.2% with fetal surgery versus 86% with postnatal surgery. Among patients who already had severe ventriculomegaly (AD ≥ 15 mm) at the time of screening, hydrocephalus complicated 79% of children with fetal surgery vs 87.5% with postnatal repair. Therefore, lesion level and ventricular size are critical to determining the likely benefit of fetal surgery and patient-specific counseling. Long-Term Management A critical component of the ongoing care of children with myelomeningocele is participation in a multidisciplinary spina bifida clinic. These clinics provide routine surveillance for important neurosurgical issues including hydrocephalus, CSF shunt failure, brainstem dysfunction due to Chiari 2 malformation, tethered cord syndrome, and neuromuscular scoliosis. Brainstem dysfunction due to a symptomatic Chiari malformation may lead to central sleep apnea, respiratory stridor, dysphagia and aspiration, and dysconjugate gaze. These symptoms are often ameliorated with a working CSF shunt. Tethered cord syndrome often affects children during periods of accelerated growth. This occurs because the neural placode is “tethered” to scar tissue formed after closure, and the distal cord is placed under tension as the axial skeleton grows rapidly. This leads to ischemia and progressive loss of function including worsening bladder function, increased muscle tone and orthopedic deformities in the lower extremities, as well as loss of endurance, back and leg pain, and progressive scoliosis. Children with myelomeningocele also require long-term management in spina bifida clinic by pediatric urologists for neurogenic bladder, pediatric orthopedic surgeons for musculoskeletal deformities, and other specialists including physical and occupational therapists, dieticians and social workers. Answers C. Folic acid supplementation dramatically decreases the prevalence of NTD. B. Secondary neurulation is involved in the formation of the filum terminale, not the spinal cord. D. Termination, postnatal surgery, and fetal surgery (for those who qualify) are all reasonable options. A. To be able to ambulate in the community, patients often require intensive physical therapy and orthotic devices. C. The likelihood of fetal surgery rescuing hydrocephalus is inversely correlated with ventricular size at the time of screening. Pearls ✓ Myelomeningocele, the most common congenital anomaly of the CNS, occurs due to failure of primary neurulation, the embryologic folding and closure of the neural tube and separation from cutaneous ectoderm. ✓ Folic acid and B12 supplementation before conception and during pregnancy can reduce the risk of myelomeningocele by 70% to 90%. ✓ The MOMS trial demonstrated that fetal surgery significantly decreases hydrocephalus requiring CSF diversion in patients with myelomeningocele, and significantly improves independent ambulation. Further refinement of the MOMS trial results has shown fetal surgery does not rescue the hydrocephalus phenotype in patients with severe ventriculomegaly (AD ≥ 15 mm) at the time of screening. ✓ Fetal surgery presents significant risk to both the mother and fetus; therefore, detailed, patient-specific prenatal counseling is critical. ✓ Long-term surveillance is essential to identify and manage problems including hydrocephalus and shunt failure, brainstem dysfunction, tethered cord syndrome, neuromuscular scoliosis, and neurogenic bladder. This is best coordinated through a multidisciplinary spina bifida clinic. SUGGESTED READING Czeizel AE, Dudás I. Prevention of the first occurrence of Neural-Tube defects by periconceptional vitamin supplementation. N Engl J Med. 1992;327(26):1832-1835. Bowman RM, McLone DG, Grant JA, Tomita T, Ito JA. Spina bifida outcome: A 25-Year prospective. Pediatr Neurosurg. 2001;34(3):114-120. Bowman RM, Mohan A, Ito J, Seibly JM, McLone DG. Tethered cord release: a long-term study in 114 patients. PED. 2001;3(3):181-187. Adzick NS, Thom EA, Spong CY, et al. A randomized trial of prenatal versus postnatal repair of myelomeningocele. N Engl J Med. 2011;364(11):993-1004. Tulipan N, Wellons JC 3rd, Thom EA, et al. Prenatal surgery for myelomeningocele and the need for cerebrospinal fluid shunt placement. J Neurosurg Pediatr. 2015;16(6):613-620. CHAPTER 3: CRANIOSYNOSTOSIS Case Presentation A 3-mo-old otherwise healthy male presented with flattening of the right occiput. His parents were concerned about the shape but even more concerned about effects on brain development. On exam, when viewed from above, the ear and forehead on the side of the flattening were displaced anteriorly. When viewed from behind, the ears were at an equal level. There were no other skull anomalies, and the child's exam was otherwise normal. Questions A head shape that is long in the antero-posterior dimension and narrow in the transverse dimension with a prominent forehead and occiput is characteristic of which of the following types of craniosynostosis: Metopic Coronal Sagittal Lambdoid A head shape notable for a triangular forehead when viewed from above with close set eyes is characteristic of which of the following types of craniosynostosis: Metopic Coronal Sagittal Lambdoid A midline prominence extending from the anterior fontanel to the frontonasal junction with an otherwise normal forehead contour would be best described as: Positional Plagiocephaly Metopic Craniosynostosis Metopic Ridging Coronal Craniosynostosis In contrast to lambdoid craniosynostosis, positional plagiocephaly often results in a head shape similar to a: Trapezoid Rectangle Circle Parallelogram Epidemiology Craniosynostosis is the premature fusion of one or mor