Extradural decompression versus duraplasty in Chiari malformation type I with syrinx: outcomes on scoliosis from the Park-Reeves Syringomyelia Research Consortium.

OBJECTIVE: Scoliosis is common in patients with Chiari malformation type I (CM-I)-associated syringomyelia. While it is known that treatment with posterior fossa decompression (PFD) may reduce the progression of scoliosis, it is unknown if decompression with duraplasty is superior to extradural decompression. METHODS: A large multicenter retrospective and prospective registry of 1257 pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for patients with scoliosis who underwent PFD with or without duraplasty. RESULTS: In total, 422 patients who underwent PFD had a clinical diagnosis of scoliosis. Of these patients, 346 underwent duraplasty, 51 received extradural decompression alone, and 25 were excluded because no data were available on the type of PFD. The mean clinical follow-up was 2.6 years. Overall, there was no difference in subsequent occurrence of fusion or proportion of patients with curve progression between those with and those without a duraplasty. However, after controlling for age, sex, preoperative curve magnitude, syrinx length, syrinx width, and holocord syrinx, extradural decompression was associated with curve progression > 10°, but not increased occurrence of fusion. Older age at PFD and larger preoperative curve magnitude were independently associated with subsequent occurrence of fusion. Greater syrinx reduction after PFD of either type was associated with decreased occurrence of fusion. CONCLUSIONS: In patients with CM-I, syrinx, and scoliosis undergoing PFD, there was no difference in subsequent occurrence of surgical correction of scoliosis between those receiving a duraplasty and those with an extradural decompression. However, after controlling for preoperative factors including age, syrinx characteristics, and curve magnitude, patients treated with duraplasty were less likely to have curve progression than patients treated with extradural decompression. Further study is needed to evaluate the role of duraplasty in curve stabilization after PFD.

Dural augmentation approaches and complication rates after posterior fossa decompression for Chiari I malformation and syringomyelia: a Park-Reeves Syringomyelia Research Consortium study.

OBJECTIVE: Posterior fossa decompression with duraplasty (PFDD) is commonly performed for Chiari I malformation (CM-I) with syringomyelia (SM). However, complication rates associated with various dural graft types are not well established. The objective of this study was to elucidate complication rates within 6 months of surgery among autograft and commonly used nonautologous grafts for pediatric patients who underwent PFDD for CM-I/SM. METHODS: The Park-Reeves Syringomyelia Research Consortium database was queried for pediatric patients who had undergone PFDD for CM-I with SM. All patients had tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and ≥ 6 months of postoperative follow-up after PFDD. Complications (e.g., pseudomeningocele, CSF leak, meningitis, and hydrocephalus) and postoperative changes in syrinx size, headaches, and neck pain were compared for autograft versus nonautologous graft. RESULTS: A total of 781 PFDD cases were analyzed (359 autograft, 422 nonautologous graft). Nonautologous grafts included bovine pericardium (n = 63), bovine collagen (n = 225), synthetic (n = 99), and human cadaveric allograft (n = 35). Autograft (103/359, 28.7%) had a similar overall complication rate compared to nonautologous graft (143/422, 33.9%) (p = 0.12). However, nonautologous graft was associated with significantly higher rates of pseudomeningocele (p = 0.04) and meningitis (p < 0.001). The higher rate of meningitis was influenced particularly by the higher rate of chemical meningitis (p = 0.002) versus infectious meningitis (p = 0.132). Among 4 types of nonautologous grafts, there were differences in complication rates (p = 0.02), including chemical meningitis (p = 0.01) and postoperative nausea/vomiting (p = 0.03). Allograft demonstrated the lowest complication rates overall (14.3%) and yielded significantly fewer complications compared to bovine collagen (p = 0.02) and synthetic (p = 0.003) grafts. Synthetic graft yielded higher complication rates than autograft (p = 0.01). Autograft and nonautologous graft resulted in equal improvements in syrinx size (p < 0.0001). No differences were found for postoperative changes in headaches or neck pain. CONCLUSIONS: In the largest multicenter cohort to date, complication rates for dural autograft and nonautologous graft are similar after PFDD for CM-I/SM, although nonautologous graft results in higher rates of pseudomeningocele and meningitis. Rates of meningitis differ among nonautologous graft types. Autograft and nonautologous graft are equivalent for reducing syrinx size, headaches, and neck pain.

Occipital-Cervical Fusion and Ventral Decompression in the Surgical Management of Chiari-1 Malformation and Syringomyelia: Analysis of Data From the Park-Reeves Syringomyelia Research Consortium.

BACKGROUND: Occipital-cervical fusion (OCF) and ventral decompression (VD) may be used in the treatment of pediatric Chiari-1 malformation (CM-1) with syringomyelia (SM) as adjuncts to posterior fossa decompression (PFD) for complex craniovertebral junction pathology. OBJECTIVE: To examine factors influencing the use of OCF and OCF/VD in a multicenter cohort of pediatric CM-1 and SM subjects treated with PFD. METHODS: The Park-Reeves Syringomyelia Research Consortium registry was used to examine 637 subjects with cerebellar tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and at least 1 yr of follow-up after their index PFD. Comparisons were made between subjects who received PFD alone and those with PFD + OCF or PFD + OCF/VD. RESULTS: All 637 patients underwent PFD, 505 (79.2%) with and 132 (20.8%) without duraplasty. A total of 12 subjects went on to have OCF at some point in their management (PFD + OCF), whereas 4 had OCF and VD (PFD + OCF/VD). Of those with complete data, a history of platybasia (3/10, P = .011), Klippel-Feil (2/10, P = .015), and basilar invagination (3/12, P < .001) were increased within the OCF group, whereas only basilar invagination (1/4, P < .001) was increased in the OCF/VD group. Clivo-axial angle (CXA) was significantly lower for both OCF (128.8 ± 15.3°, P = .008) and OCF/VD (115.0 ± 11.6°, P = .025) groups when compared to PFD-only group (145.3 ± 12.7°). pB-C2 did not differ among groups. CONCLUSION: Although PFD alone is adequate for treating the vast majority of CM-1/SM patients, OCF or OCF/VD may be occasionally utilized. Cranial base and spine pathologies and CXA may provide insight into the need for OCF and/or OCF/VD.

Factors associated with syrinx size in pediatric patients treated for Chiari malformation type I and syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium.

OBJECTIVE: Factors associated with syrinx size in pediatric patients undergoing posterior fossa decompression (PFD) or PFD with duraplasty (PFDD) for Chiari malformation type I (CM-I) with syringomyelia (SM; CM-I+SM) are not well established. METHODS: Using the Park-Reeves Syringomyelia Research Consortium registry, the authors analyzed variables associated with syrinx radiological outcomes in patients (< 20 years old at the time of surgery) with CM-I+SM undergoing PFD or PFDD. Syrinx resolution was defined as an anteroposterior (AP) diameter of ≤ 2 mm or ≤ 3 mm or a reduction in AP diameter of ≥ 50%. Syrinx regression or progression was defined using 1) change in syrinx AP diameter (≥ 1 mm), or 2) change in syrinx length (craniocaudal, ≥ 1 vertebral level). Syrinx stability was defined as a < 1-mm change in syrinx AP diameter and no change in syrinx length. RESULTS: The authors identified 380 patients with CM-I+SM who underwent PFD or PFDD. Cox proportional hazards modeling revealed younger age at surgery and PFDD as being independently associated with syrinx resolution, defined as a ≤ 2-mm or ≤ 3-mm AP diameter or ≥ 50% reduction in AP diameter. Radiological syrinx resolution was associated with improvement in headache (p < 0.005) and neck pain (p < 0.011) after PFD or PFDD. Next, PFDD (p = 0.005), scoliosis (p = 0.007), and syrinx location across multiple spinal segments (p = 0.001) were associated with syrinx diameter regression, whereas increased preoperative frontal-occipital horn ratio (FOHR; p = 0.007) and syrinx location spanning multiple spinal segments (p = 0.04) were associated with syrinx length regression. Scoliosis (HR 0.38 [95% CI 0.16-0.91], p = 0.03) and smaller syrinx diameter (5.82 ± 3.38 vs 7.86 ± 3.05 mm; HR 0.60 [95% CI 0.34-1.03], p = 0.002) were associated with syrinx diameter stability, whereas shorter preoperative syrinx length (5.75 ± 4.01 vs 9.65 ± 4.31 levels; HR 0.21 [95% CI 0.12-0.38], p = 0.0001) and smaller pB-C2 distance (6.86 ± 1.27 vs 7.18 ± 1.38 mm; HR 1.44 [95% CI 1.02-2.05], p = 0.04) were associated with syrinx length stability. Finally, younger age at surgery (8.19 ± 5.02 vs 10.29 ± 4.25 years; HR 1.89 [95% CI 1.31-3.04], p = 0.01) was associated with syrinx diameter progression, whereas increased postoperative syrinx diameter (6.73 ± 3.64 vs 3.97 ± 3.07 mm; HR 3.10 [95% CI 1.67-5.76], p = 0.003), was associated with syrinx length progression. PFD versus PFDD was not associated with syrinx progression or reoperation rate. CONCLUSIONS: These data suggest that PFDD and age are independently associated with radiological syrinx improvement, although forthcoming results from the PFDD versus PFD randomized controlled trial (NCT02669836, clinicaltrials.gov) will best answer this question.

Heritable spina bifida in sheep: A potential model for fetal repair of myelomeningocele.

BACKGROUND/PURPOSE: In 2004, a heritable occurrence of spina bifida was reported in sheep on a farm in the United States. We maintained and characterized the spina bifida phenotype in this flock to assess its potential as an alternative surgical model. METHODS: A breeding strategy was developed in which the sheep were crossed to maintain or increase the occurrence of spina bifida. Measurements and observations were recorded regarding lesion size, birthweight, ambulatory capacity, or urological function, and necropsies were performed on spina bifida afflicted lambs in conjunction with magnetic resonance imaging to determine the character of the spina bifida defects and assess the presence of Chiari-like malformations or hydrocephalus. RESULTS: The defects were observed to be more prevalent in ram lambs, and the rate of spina bifida per litter could be increased through backcrossing or by selection of a productive ewe breed. The lambs displayed a range of ambulatory and urological deficits which could be used to evaluate new fetal repair methodologies. Finally, affected lambs were shown to demonstrate severe Chiari malformations and hydrocephalus. CONCLUSIONS: We have determined that use of these sheep as a natural source for spina bifida fetuses is feasible and could supplement the deficits of current sheep models for myelomeningocele repair. LEVEL OF EVIDENCE: Level IV.

Outcomes in children undergoing posterior fossa decompression and duraplasty with and without tonsillar reduction for Chiari malformation type I and syringomyelia: a pilot prospective multicenter cohort study.

OBJECTIVE: Despite significant advances in diagnostic and surgical techniques, the surgical management of Chiari malformation type I (CM-I) with associated syringomyelia remains controversial, and the type of surgery performed is surgeon dependent. This study's goal was to determine the feasibility of a prospective, multicenter, cohort study for CM-I/syringomyelia patients and to provide pilot data that compare posterior fossa decompression and duraplasty (PFDD) with and without tonsillar reduction. METHODS: Participating centers prospectively enrolled children suffering from both CM-I and syringomyelia who were scheduled to undergo surgical decompression. Clinical data were entered into a database preoperatively and at 1-2 weeks, 3-6 months, and 1 year postoperatively. MR images were evaluated by 3 independent, blinded teams of neurosurgeons and neuroradiologists. The primary endpoint was improvement or resolution of the syrinx. RESULTS: Eight clinical sites were chosen based on the results of a published questionnaire intended to remove geographic and surgeon bias. Data from 68 patients were analyzed after exclusions, and complete clinical and imaging records were obtained for 55 and 58 individuals, respectively. There was strong agreement among the 3 radiology teams, and there was no difference in patient demographics among sites, surgeons, or surgery types. Tonsillar reduction was not associated with > 50% syrinx improvement (RR = 1.22, p = 0.39) or any syrinx improvement (RR = 1.00, p = 0.99). There were no surgical complications. CONCLUSIONS: This study demonstrated the feasibility of a prospective, multicenter surgical trial in CM-I/syringomyelia and provides pilot data indicating no discernible difference in 1-year outcomes between PFDD with and without tonsillar reduction, with power calculations for larger future studies. In addition, the study revealed important technical factors to consider when setting up future trials. The long-term sequelae of tonsillar reduction have not been addressed and would be an important consideration in future investigations.

Concepts in the neurosurgical care of patients with spinal neural tube defects: An embryologic approach.

BACKGROUND: The neural tube defects (NTDs) are a heterogeneous group of structural birth defects that arise from a complex array of multiple genetic and environmental factors and adversely affect the structure and function of the brain and spinal cord. Spinal NTDs are clinically more common than cranial NTDs. There remains a significant gap in linking the multiple NTD phenotypes to current genomic understanding. METHODS: This article summarizes the neurosurgical clinical approach to spinal NTDs by correlating each step of embryonic development of the human nervous system with key management concepts for defects that arise at that step. RESULTS: The NTDs are broadly classified as open or closed. Open defects include myelomeningocele (MMC), encephalocele, and anencephaly. Closed defects are also known as occult spinal dysraphism and are characterized by intact skin over the spinal defect. They are more common and often cause neurologic decline from tethered cord syndrome. Failure of primary neurulation gives rise to open myelomeningocele (MMC). Surgical closure of an open MMC focuses on realigning the tissue layers that failed to separate during neurulation. In utero closure is a promising recent technique. Chronic neurosurgical management largely focuses treating hydrocephalus. The Chiari II malformation is uniformly present in MMC patients and may cause brainstem dysfunction. Tethered spinal cord may progressively impair normal neurologic function but typically responds well to surgical untethering. CONCLUSIONS: Surgical closure of MMC centers on approximated realignment of embryologically disordered neural tissue. Clinical surgical management decisions in the spinal NTDs remains challenging but standardized principles have emerged.

Overview on neural tube defects: From development to physical characteristics.

Neural tube defects (NTDs) are the second most common congenital malformations in humans affecting the development of the central nervous system. Although NTD pathogenesis has not yet been fully elucidated, many risk factors, both genetic and environmental, have been extensively reported. Classically divided in two main sub-groups (open and closed defects) NTDs present extremely variable prognosis mainly depending on the site of the lesion. Herein, we review the literature on the histological and pathological features, epidemiology, prenatal diagnosis, and prognosis, based on the type of defect, with the aim of providing important information based on NTDs classification for clinicians and scientists.

Utility of a child abuse screening guideline in an urban pediatric emergency department.

BACKGROUND: Previous studies have found racial and socioeconomic status bias in the way clinicians screen for and detect child abuse in patients presenting to the emergency department. We hypothesized that implementing a guideline for screening would attenuate this bias. METHODS: An algorithm for child abuse screening in patients younger than 1 year presenting with fractures was developed for a pediatric trauma center emergency department. Data were collected 1.5 years before and after implementation of the algorithm to investigate implementation success. Data were compared before and after the implementation of the algorithm using χ and univariate logistic regression analysis. RESULTS: The characteristics of patients with fractures were similar before and after the algorithm implementation. Implementation of the algorithm was related to a significant increase in algorithm required screenings: skeletal survey (p < 0.001), urinalysis (p < 0.001), and transaminase levels (p < 0.001). The racial composition of those screened did not change after the implementation of the protocol. Children with government-subsidized or no insurance were more likely to be screened for child abuse via skeletal survey before the algorithm implementation compared with those with private insurance (odds ratio, 2.7; 95% confidence interval, 1.2-6.0; p = 0.017). This relationship did not exist after the algorithm implementation (odds ratio, 1.2; 95% confidence interval, 0.56-2.46; p = 0.66). Final determination of child abuse was related to insurance status both before and after the algorithm implementation. CONCLUSION: A child abuse screening algorithm was successfully implemented in an urban trauma center. After implementation, screening was no longer associated with socioeconomic status of the patient's family, although final determination of child abuse still was. Additional research is needed to determine utility of unbiased screening on patient outcomes. LEVEL OF EVIDENCE: Therapeutic study, level IV.

Treatment of cephalocranial disproportion in shunt-induced slit ventricle syndrome with cranial vault distraction osteogenesis.

BACKGROUND: Slit ventricle syndrome (SVS) is a known late complication of shunting procedures. Some patients develop cephalocranial disproportion (CCD) that will require surgical treatment to increase craniocerebral compliance. METHODS: We performed cranial vault distraction osteogenesis to treat 2 teenage patients who presented with SVS, increased intracranial pressure and CCD. Bilateral temporo-parieto-occipital craniotomies were performed. RESULTS: Both patients successfully completed distraction and consolidated without the need for bone grafting. Postoperatively, both patients showed an increase in intracranial and intraventricular volume, as well as decreased shunt revisions. One patient had improvement of her headaches, while the other continues to have chronic headaches. CONCLUSION: Distraction osteogenesis is an option to expand the cranial vault in older children with SVS and CCD, in which the traditional cranial vault expansion would be a challenge and may or may not provide adequate expansion.

Resorption of PDLLA plates as a nidus for recurrent langerhans cell histiocytosis.

Resorbable plating systems have been adapted into routine use for craniofacial reconstruction in children. After implantation in some patients, the area around the plates can develop palpable and visible fibrous capsules, with underlying bone resorption and a significant foreign-body giant cell reaction. The reaction is usually self-limited. We report a case in which Langerhans cell histiocytosis was resected, and then recurred at the sites of resorbing plate and screw placement in association with a foreign-body giant cell reaction.

Antiepileptic drugs and pregnancy outcomes.

The treatment of epilepsy in women of reproductive age remains a clinical challenge. While most women with epilepsy (WWE) require anticonvulsant drugs for adequate control of their seizures, the teratogenicity associated with some antiepileptic drugs (AEDs) is a risk that needs to be carefully addressed. Antiepileptic medications are also used to treat an ever broadening range of medical conditions such as bipolar disorder, migraine prophylaxis, cancer, and neuropathic pain. Despite the fact that the majority of pregnancies of WWE who are receiving pharmacological treatment are normal, studies have demonstrated that the risk of having a pregnancy complicated by a major congenital malformation is doubled when comparing the risk of untreated pregnancies. Furthermore, when AEDs are used in polytherapy regimens, the risk is tripled, especially when valproic acid (VPA) is included. However, it should be noted that the risks are specific for each anticonvulsant drug. Some investigations have suggested that the risk of teratogenicity is increased in a dose-dependent manner. More recent studies have reported that in utero exposure to AEDs can have detrimental effects on the cognitive functions and language skills in later stages of life. In fact, the FDA just issued a safety announcement on the impact of VPA on cognition (Safety Announcement 6-30-2011). The purpose of this document is to review the most commonly used compounds in the treatment of WWE, and to provide information on the latest experimental and human epidemiological studies of the effects of AEDs in the exposed embryos.

The reliability and advantages of the sentinel vein as a microsurgical recipient vessel.

Free flaps to the scalp, calvaria, and anterior and middle cranial fossae are typically transferred to the superficial temporal artery and vein. Occasionally the superficial temporal vein is unsuitable for microvascular anastomosis. In such cases, we have had success using the sentinel vein, a perforating vein located in the anterior aspect of the deep temporal fat pad. This article describes the pertinent anatomy, our clinical experience, and the advantages of the sentinel vein as a microsurgical recipient vessel.

Treatment practices for Chiari malformation type I with syringomyelia: results of a survey of the American Society of Pediatric Neurosurgeons.

OBJECT: The purpose of this study was to report the results of a survey of the American Society of Pediatric Neurosurgeons (ASPN) on treatment of Chiari malformation Type I (CM-I) with syringomyelia. METHODS: A questionnaire was circulated during the 2006 meeting of the ASPN, in which surgeons were surveyed on their management of patients with CM-I and syringomyelia. The survey consisted of questions about 4 clinical scenarios, common causes of surgical failures, and complications. RESULTS: There were 72 respondents, representing more than 90% of attendees at the 2006 ASPN meeting and approximately half of the society's members. The majority of respondents (85%) reported that they perform posterior fossa decompression as first-line treatment for CM-I with syringomyelia. Seven percent perform bony decompression alone, 36% open the dura, and 27% shrink the tonsils. Very few respondents indicated that they offer syrinx drainage as first-line therapy (< 3%). Although all respondents reported that they treat symptomatic CM-I/syringomyelia patients surgically, 15% of respondents indicated that they do not operate on asymptomatic patients. Finally, respondents stated that their most common complications are pseudomeningocele and chemical meningitis. CONCLUSIONS: This survey, given to a representative group of experienced North American pediatric neurosurgeons, confirms that posterior fossa decompression is still the preferred treatment modality in children with CM-I and syringomyelia, regardless of symptoms. Although most surgeons open the dura, preferred techniques for decompression vary. In contrast to the results of past surveys, conservative follow-up is now only used by a minority of respondents and only in the asymptomatic patient, and primary syrinx drainage seems to have lost popularity. A multicenter trial of surgical outcomes has been designed based on the information from this survey.

Genetic basis of susceptibility to teratogen induced birth defects.

Birth defects remain the leading cause of infant death in US. The field of teratology has been focused on the causes and underlying mechanisms of birth defects for decades, yet our understanding of these critical issues remain unacceptably vague. Conclusions from years of animal and human studies made it clear that the vast majority of birth defects have multifactorial origins, with contributions from environmental and genetic factors. The environment comprises not only of the physical, biological, and chemical external environment surrounding the pregnant woman, but it also includes the internal environment of the woman's body that interact with the developing embryo in a complex fashion. The importance of maternal and embryonic genetic factors consisting of countless genetic variants/mutations that exist within every individual contribute to birth defect susceptibility is only now being more fully appreciated. This great complexity of the genome and its diversity within individuals and populations seems to be the principal reason why the same teratogenic exposure can induce severe malformation in one embryo, while fail to do so to other exposed embryos. As the interaction between genetic and environmental factors has long been recognized as the first "Principle of Teratology" by Wilson and Warkany [1965. Teratology: Principles and techniques. Chicago: University of Chicago Press], it is only recently that the appropriate investigative tools have been developed with which to fully investigate this fundamental principle. The introduction of high throughput technologies like whole genome sequencing or genome-wide association studies are promising to deliver an enormous amount of new data that will shed light on the genomic factors that contribute susceptibility to environmental teratogens. In this review, we attempt to summarize the epidemiological and experimental literature concerning birth defects whose phenotypic expression can be clearly related to the interactions between several select environmental factors and those genetic pathways in which they are most likely to have significant modifying effects. © 2011 Wiley-Liss, Inc.

Defining the signs and symptoms of Chiari malformation type I with and without syringomyelia.

OBJECTIVE: There is a lack of correlation between how Chiari malformations are defined and the plethora of signs and symptoms attributed to these malformations. The purpose of this review is to understand the signs and symptoms of Chiari malformations in relation to the newer descriptions that define these malformations. METHODS: We reviewed the literature to determine what are the pertinent signs and symptoms related to Chiari malformations, with special attention to Chiari type I malformations. RESULTS: There were several strategies identified in the literature regarding how to define the morphology of Chiari malformations based on modern imaging and pathogenetic theories. The signs and symptoms were organized based on the type and location along the neuraxis. Although suggestive, it appears that symptoms have not been clearly correlated to anatomic variations of Chiari type I malformation. In addition, we discuss how magnetic resonance imaging has found a significant number of patients that lack or have a paucity of symptoms. CONCLUSIONS: Current understanding of the signs and symptoms for Chiari malformations has been based on a dated standard definition of these malformations. There is a need to redefine these malformations in order to uncover the natural history of the disease and how symptoms relate to this disorder.

Hearing evaluation in pediatric patients treated at the hospital following head injury.

The purpose of this study was to assess the results of a hearing evaluation protocol among 130 pediatric patients with a head injury. Sixteen of these patients failed an audiology evaluation. Ten were thought to have failed based on congestion/middle ear dysfunction, while 6 patients had temporary or permanent hearing loss thought to be related to their injury. The majority who failed because of their injury had temporal bone fractures and abnormal visual ear examination results. More research on trauma-related hearing loss following various types of head injuries and skull fractures in pediatric patients of varying ages is needed.