For the past 2 decades, clinical and basic science researchers have gained significant insights into the molecular and genetic pathways associated with common forms of craniosynostosis. This has led to invaluable information for families and physicians in their attempts to understand the heterogeneity of craniosynostosis. Genetic mutations have been identified in the fibroblast growth factor receptors (FGFRs) as well as in other targets, including TWIST1, BMP, and RUNX2. Greater understanding of these and other pathways has led to the development of innovative approaches for applying medical therapies to the treatment of craniosynostosis, in particular by maintaining suture patency. In this article, the authors discuss the molecular pathophysiological mechanisms underlying various forms of craniosynostosis. They also highlight recent developments in the field of molecular craniosynostosis research with the hope of identifying targets for medical therapies that might augment the results of surgical intervention.
Jennifer Kosty and Timothy W. Vogel
Timothy W. Vogel, Sunil Manjila and Alan R. Cohen
Giant occipitoparietal encephaloceles are rare forms of neurodevelopmental defects whose etiologies remain uncertain. Their occurrence can lead to variable neurological outcomes depending on the extent of cerebral cortex involved and the ability to repair the defect. In addition, encephaloceles may be associated with various genetic syndromes and familial inheritance. Here, the authors describe a unique constellation of malformations associated with the case of a giant occipitoparietal meningoencephalocele with herniation of cortical tissue and continuity with the ventricular system. The patient had a cleft lip and palate, hemivertebrae of the thoracic spine, a patent ductus arteriosus, a ventricular septal defect, and coarctation of the aorta. To identify the genetic underpinnings of these malformations, fluorescence in situ hybridization and microarray analysis were performed and revealed an 80.65-kb gain within chromosome band 2p11.2. Duplications of this region involving RMND5A, whose product contains a C-terminal to lis homology (LisH) domain, have not previously been associated with a defined phenotype but may present insight into encephalocele formation. Surgical repair and follow-up for the neurological malformations are also discussed.
Timothy W. Vogel, Brian J. Dlouhy and Matthew A. Howard III
The object of this study was to evaluate the causes of plunging events associated with automatic-releasing cranial perforators at the authors' institution.
The authors analyzed a consecutive series of 1652 cranial procedures involving one type of automaticreleasing cranial perforator over a 2-year period. Plunging occurrences were recorded for 2 drill speeds: 1000 rpm in the 1st year and 800 rpm during the 2nd year. Intraoperative observations, neuroimaging studies, and clinical data were evaluated for each plunging event.
The authors identified 9 plunging events for an overall incidence of 0.54%. In the 1st year, they identified 2 plunging events at a speed of 1000 rpm for an incidence of 0.19%. In an effort to reduce this occurrence, the speed of the drill was lowered to 800 rpm. There were 7 additional events, for a significantly increased incidence of 1.16% (p = 0.014, Fisher exact test) after the change was implemented. These cases spanned a number of procedures in adults and pediatric patients, including ventriculostomy placement, craniotomies for tumor resection, tumor biopsy, and endoscopic third ventriculostomy. Despite plunging, no immediate postoperative complications were noted on clinical examination.
While technology continues to improve cranial perforator performance, the use of such a device is still associated with a risk of complications causing dural lacerations and injury to the underlying cortex. Decreasing the drill speed may not decrease the incidence of plunging.
Timothy W. Vogel, Brian J. Dlouhy and Matthew A. Howard III
Spontaneous intracranial hypotension (SIH) is a syndrome with serious neurological sequelae. As demonstrated by the following report, recurrent episodes of SIH can be difficult to diagnose when associated with other neurosurgical procedures, such as craniectomies. In this paper, the authors demonstrate SIH presenting as a subdural hematoma with recurrence of CSF leaks. Spontaneous intracranial hypotension was further complicated by paradoxical herniation following a craniectomy. Treatment of SIH necessitated multiple epidural blood patches for CSF leaks at different spinal levels and at different times. The efficacy of each epidural blood patch was confirmed with radionuclide imaging. Confirmation of effective blood patch placement may be useful for identifying patients at risk for a failed epidural blood patch or for patients whose neurological examination results have not fully improved.
Timothy W. Vogel, Biji Bahuleyan, Shenandoah Robinson and Alan R. Cohen
Hydrocephalus remains a major public health problem. Conventional treatment has relied on extracranial shunting of CSF to another systemic site, but this approach is associated with a high rate of complications. Endoscopic third ventriculostomy (ETV) is a novel treatment for select forms of hydrocephalus that can eliminate the need for implantation of a lifelong ventricular shunt system. However, the indications for ETV are contested and its long-term effectiveness is not well established.
The authors selected 100 consecutive patients who underwent ETV for hydrocephalus beginning in 1994. Patients were enrolled and treated at a single institution by a single surgeon. The primary outcome was success of ETV, with success defined as no need for subsequent surgery for hydrocephalus.
Ninety-five patients satisfied the inclusion criteria. The mean follow-up period was 5.1 years (median 4.7 years) with follow-up data available for as long as 17 years. Patients commonly presented with headache (85%), ataxia (34%), emesis (29%), and changes in vision (27%). The success rate for ETV was 75%. Twenty-one patients (22%) in the series had malfunctioning shunts preoperatively and 13 (62%) were successfully treated with ETV. Preoperative inferior bowing of the third ventricle floor on MRI was significantly associated with ETV success (p < 0.05).
Endoscopic third ventriculostomy is an effective and durable treatment for select patients with hydrocephalus. When successful, the procedure eliminates the lifelong complications associated with implanted ventricular shunts.
Alan R. Cohen, Timothy W. Vogel and Hart G. W. Lidov
The authors describe an 8-year-old girl who underwent emergency posterior fossa surgery for resection of a large cerebellar astrocytoma in November 1939. The surgery was carried out by Franc D. Ingraham at Boston Children's Hospital a decade after he established the first pediatric neurosurgical service in the world at the same institution. Four years later the tumor recurred and the patient underwent repeat resection followed by external-beam radiation therapy. The pathological diagnosis by Sidney Farber was fibrillary astrocytoma.
The young girl is currently a healthy, functional 82-year-old woman. The authors believe that this 74-year follow-up represents one of the longest in history, if not the longest, of a patient undergoing resection of a brain tumor. A recent MRI study shows postoperative changes with no evidence of residual or recurrent tumor. The original block tissue specimen had been preserved. It was restained and examined, revealing the pathological diagnosis to be juvenile pilocytic astrocytoma.
The case is analyzed in the context of Ingraham's powerful and lasting impact on the field of pediatric neurosurgery.
Timothy W. Vogel, Calvin S. Carter, Kingsley Abode-Iyamah, Qihong Zhang and Shenandoah Robinson
Neural tube defects (NTDs) are a set of disorders that occur from perturbation of normal neural development. They occur in open or closed forms anywhere along the craniospinal axis and often result from a complex interaction between environmental and genetic factors. One burgeoning area of genetics research is the effect of cilia signaling on the developing neural tube and how the disruption of primary cilia leads to the development of NTDs. Recent progress has implicated the hedgehog (Hh), wingless-type integration site family (Wnt), and planar cell polarity (PCP) pathways in primary cilia as involved in normal neural tube patterning. A set of disorders involving cilia function, known as ciliopathies, offers insight into abnormal neural development. In this article, the authors discuss the common ciliopathies, such as Meckel-Gruber and Joubert syndromes, that are associated with NTDs, and review cilia-related signaling cascades responsible for mammalian neural tube development. Understanding the contribution of cilia in the formation of NTDs may provide greater insight into this common set of pediatric neurological disorders.
Sunil Manjila, Timothy W. Vogel, Yunwei Chen, Mark S. Rodgers and Alan R. Cohen
Hypothalamic hamartomas (HHs) are rare developmental lesions arising from the inferior hypothalamus that may cause gelastic seizures and central precocious puberty. Cystic changes in HHs are rare, usually occurring in giant lesions. The authors describe an unusual case of cystic HH masquerading as a suprasellar arachnoid cyst in an 18-month-old girl presenting with precocious puberty. Microsurgical removal of the lesion led to complete resolution of the precocious puberty on long-term follow-up. This case is the first reported HH with pathological demonstration of corticotropin-releasing hormone immunostaining in the solid tumor and glial cells in the cyst wall of the lesion. The clinical and radiological characteristics of HHs are reviewed, along with the unique surgical strategies used to manage cystic lesions in the suprasellar region.
Libby Kosnik-Infinger, Craig Gendron, Christopher B. Gordon, Brian S. Pan, John A. van Aalst and Timothy W. Vogel
Hypophosphatasia (HPP) is a rare inherited disorder of bone metabolism that results in the loss of function of the gene coding for tissue-nonspecific alkaline phosphatase (TNSALP). Patients with HPP have defective bone mineralization as well as craniosynostosis that can be seen in the infantile and childhood forms of this disease. Traditionally, HPP has had a poor prognosis, with few children surviving to exhibit the phenotype of clinical craniosynostosis that requires surgical intervention. Here, the authors report on new advancements in enzyme replacement therapy (ERT) for children affected by HPP, allowing these patients to survive and undergo surgery to address complex craniosynostosis. The authors discuss their case series of 4 HPP patients treated at their institution with ERT who have undergone successful surgical intervention for craniosynostosis. These children had no complications related to their surgeries and exhibited decreased neurological symptoms following cranial vault remodeling. This study reveals that ERT administered either pre- or post- operatively paired with cranial vault remodeling strategies can yield improved neurological outcomes in children affected by HPP.
Ammar H. Hawasli, Thomas L. Beaumont, Timothy W. Vogel, Albert S. Woo and Jeffrey R. Leonard
Acalvaria is a rare congenital malformation characterized by an absence of skin and skull. The authors describe a newborn at an estimated 38 weeks gestational age who was delivered via cesarean section from a 32-year-old mother. Upon delivery, the child was noted to have a frontal encephalocele and an absence of calvaria including skull and skin overlying the brain. A thin membrane representing dura mater was overlying the cortical tissue. After multiple craniofacial operations, including repair of the encephalocele and application of cultured keratinocytes over the rostral defect, the patient demonstrated significant closure of the calvarial defect and was alive at an age of more than 17 months with near-average development.