Complications following pediatric cranioplasty after decompressive craniectomy: a multicenter retrospective study.

OBJECTIVE In children, the repair of skull defects arising from decompressive craniectomy presents a unique set of challenges. Single-center studies have identified different risk factors for the common complications of cranioplasty resorption and infection. The goal of the present study was to determine the risk factors for bone resorption and infection after pediatric cranioplasty. METHODS The authors conducted a multicenter retrospective case study that included all patients who underwent cranioplasty to correct a skull defect arising from a decompressive craniectomy at 13 centers between 2000 and 2011 and were less than 19 years old at the time of cranioplasty. Prior systematic review of the literature along with expert opinion guided the selection of variables to be collected. These included: indication for craniectomy; history of abusive head trauma; method of bone storage; method of bone fixation; use of drains; size of bone graft; presence of other implants, including ventriculoperitoneal (VP) shunt; presence of fluid collections; age at craniectomy; and time between craniectomy and cranioplasty. RESULTS A total of 359 patients met the inclusion criteria. The patients' mean age was 8.4 years, and 51.5% were female. Thirty-eight cases (10.5%) were complicated by infection. In multivariate analysis, presence of a cranial implant (primarily VP shunt) (OR 2.41, 95% CI 1.17-4.98), presence of gastrostomy (OR 2.44, 95% CI 1.03-5.79), and ventilator dependence (OR 8.45, 95% CI 1.10-65.08) were significant risk factors for cranioplasty infection. No other variable was associated with infection. Of the 240 patients who underwent a cranioplasty with bone graft, 21.7% showed bone resorption significant enough to warrant repeat surgical intervention. The most important predictor of cranioplasty bone resorption was age at the time of cranioplasty. For every month of increased age the risk of bone flap resorption decreased by 1% (OR 0.99, 95% CI 0.98-0.99, p < 0.001). Other risk factors for resorption in multivariate models were the use of external ventricular drains and lumbar shunts. CONCLUSIONS This is the largest study of pediatric cranioplasty outcomes performed to date. Analysis included variables found to be significant in previous retrospective reports. Presence of a cranial implant such as VP shunt is the most significant risk factor for cranioplasty infection, whereas younger age at cranioplasty is the dominant risk factor for bone resorption.

Growth and alignment of the pediatric subaxial cervical spine following rigid instrumentation and fusion: a multicenter study of the Pediatric Craniocervical Society.

OBJECTIVE The long-term effects of surgical fusion on the growing subaxial cervical spine are largely unknown. Recent cross-sectional studies have demonstrated that there is continued growth of the cervical spine through the teenage years. The purpose of this multicenter study was to determine the effects of rigid instrumentation and fusion on the growing subaxial cervical spine by investigating vertical growth, cervical alignment, cervical curvature, and adjacent-segment instability over time. METHODS A total of 15 centers participated in this multi-institutional retrospective study. Cases involving children less than 16 years of age who underwent rigid instrumentation and fusion of the subaxial cervical spine (C-2 and T-1 inclusive) with at least 1 year of clinical and radiographic follow-up were investigated. Charts were reviewed for clinical data. Postoperative and most recent radiographs, CT, and MR images were used to measure vertical growth and assess alignment and stability. RESULTS Eighty-one patients were included in the study, with a mean follow-up of 33 months. Ninety-five percent of patients had complete clinical resolution or significant improvement in symptoms. Postoperative cervical kyphosis was seen in only 4 patients (5%), and none developed a swan-neck deformity, unintended adjacent-level fusion, or instability. Of patients with at least 2 years of follow-up, 62% demonstrated growth across the fusion construct. On average, vertical growth was 79% (4-level constructs), 83% (3-level constructs), or 100% (2-level constructs) of expected growth. When comparing the group with continued vertical growth to the one without growth, there were no statistically significant differences in terms of age, sex, underlying etiology, surgical approach, or number of levels fused. CONCLUSIONS Continued vertical growth of the subaxial spine occurs in nearly two-thirds of children after rigid instrumentation and fusion of the subaxial spine. Failure of continued vertical growth is not associated with the patient's age, sex, underlying etiology, number of levels fused, or surgical approach. Further studies are needed to understand this dichotomy and determine the long-term biomechanical effects of surgery on the growing pediatric cervical spine.

Pediatric Pituitary Adenoma: Case Series, Review of the Literature, and a Skull Base Treatment Paradigm.

Background Pediatric pituitary adenoma is a rare skull base neoplasm, accounting for 3% of all intracranial neoplasms in children and 5% of pituitary adenomas. Compared with pituitary tumors in adults, secreting tumors predominate and longer disease trajectories are expected due to the patient age resulting in a natural history and treatment paradigm that is complex and controversial. Objectives The aims of this study were to describe a large, single-institution series of pediatric pituitary adenomas with extensive long-term follow-up and to conduct a systematic review examining outcomes after pituitary adenoma surgery in the pediatric population. Methods The study cohort was compiled by searching institutional pathology and operative reports using diagnosis and site codes for pituitary and sellar pathology, from 1956 to 2016. Systematic review of the English language literature since 1970 was conducted using PubMed, MEDLINE, Embase, and Google Scholar. Results Thirty-nine surgically managed pediatric pituitary adenomas were identified, including 15 prolactinomas, 14 corticotrophs, 7 somatotrophs, and 4 non-secreting adenomas. All patients underwent transsphenoidal resection (TSR) as the initial surgical treatment. Surgical cure was achieved in 18 (46%); 21 experienced recurrent/persistent disease, with secondary treatments including repeat surgery in 10, radiation in 14, adjuvant pharmacotherapy in 11, and bilateral adrenalectomy in 3. At the last follow-up (median 87 months, range 3-581), nine remained with recurrent/persistent disease (23%). Thirty-seven publications reporting surgical series of pediatric pituitary adenomas were included, containing 1,284 patients. Adrenocorticotropic hormone (ACTH)-secreting tumors were most prevalent (43%), followed by prolactin (PRL)-secreting (37%), growth hormone (GH)-secreting (12%), and nonsecreting (7%). Surgical cure was reported in 65%. Complications included pituitary insufficiency (23%), permanent visual dysfunction (6%), chronic diabetes insipidus (DI) (3%), and postoperative cerebrospinal fluid (CSF) leak (4%). Mean follow-up was 63 months (range 0-240), with recurrent/persistent disease reported in 18% at the time of last follow-up. Conclusion Pediatric pituitary adenomas are diverse and challenging tumors with complexities far beyond those encountered in the management of routine adult pituitary disease, including nuanced decision-making, a technically demanding operative environment, high propensity for recurrence, and the potentially serious consequences of hypopituitarism with respect to fertility and growth potential in a pediatric population. Optimal treatment requires a high degree of individualization, and patients are most likely to benefit from consolidated, multidisciplinary care in highly experienced centers.

Clinical and surgical management of a congenital Type II split cord malformation presenting with progressive cranial neuropathies: case report.

Split cord malformation (SCM) is a rare abnormality of notochord development. The majority of cases occur in the thoracolumbar region, with more than 30 cases of cervical SCM reported. The clinical impact of SCMs involving the cervical cord is therefore largely unknown. In addition, the concomitant finding of brainstem involvement is presumably incompatible with life in the majority of patients, resulting in a paucity of data regarding this clinical scenario. In this paper the authors present the first case, to their knowledge, of an incomplete cervical SCM involving the brainstem and discuss its clinical impact, diagnosis, and management.

Accuracy of Pedicle Screw Placement in Children 10 Years or Younger Using Navigation and Intraoperative CT.

STUDY DESIGN: A consecutive case series. OBJECTIVE: To determine the revision rate for pedicle screws placed using intraoperative CT and image-guided navigation in children 10 years or younger. SUMMARY OF BACKGROUND DATA: Screws are frequently used for spinal instrumentation in young children, although this is only by physician-directed use. This is a multicenter retrospective study of patients aged 10 years or younger, who underwent spinal screw instrumentation with image-guided navigation. We hypothesized that intraoperative navigation would result in a high rate of accuracy for screw placement. METHODS: Between 2007 and 2013, 130 pedicle and 7 lateral mass screws were placed in 16 consecutive patients undergoing a total of 17 surgeries at 2 institutions. Mean age at surgery was 6.9 years (range, 0.8-10.9 y). Screws were placed using an open technique with intraoperative CT (O-arm) and image-guided navigation (Stealth). Procedures included: growing spine device (3), hemivertebrae excision (4), posterior fusion (7), cervical fusion (2), and vertebral column resection (1). Congenital deformity was the most common diagnosis. Primary outcome measures were need for intraoperative screw revision or complication associated with screw placement. RESULTS: Mean number of screws used per procedure was 8.1 (range, 2-17). Screws were placed from C1 to L5. Of the 137 screws, 3 required revision to shorter screws for an overall accuracy rate of 97.8%. In 1 case, a right T3 screw was revised due to anterior penetration. In another case, left-sided T1 and T2 pedicle screws were shortened 5 mm because they had penetrated the anterior aspect of their respective vertebral bodies. There were no screw-related complications. CONCLUSIONS: In this series, image-guided navigation resulted in accurate placement of screws in patients aged 10 years or younger with no associated intraoperative complications. The navigated accuracy rate (97.8%) is significantly higher (P=0.01) than the reported 90.9% pedicle screw accuracy rate without navigation in the same age group by Baghdadi and colleagues. Intraoperative CT and image guidance were useful in our practice for placement of screws in skeletally immature patients.

Current Selection Criteria and Perioperative Therapy Used for Fetal Myelomeningocele Surgery.

OBJECTIVE: To determine the current maternal and fetal selection criteria and operative approaches used at centers performing fetal myelomeningocele surgery. METHODS: The 17 principal investigators participating in the Fetal Myelomeningocele Consortium were asked to participate in an anonymous online survey regarding the current practice of maternal-fetal surgery for neural tube defect repair and results were tabulated. The 35-question survey related to diagnostic testing, inclusion and exclusion criteria, and clinical management. RESULTS: Sixty-five percent (11/17) of principal investigators responded to the survey and not all centers responded to all 35 questions. All centers continue to use magnetic resonance imaging in their preoperative evaluation. Diagnostic testing from amniocentesis is varied: 5 of 11 (45%) require amniotic fluid α-fetoprotein, 4 of 10 (40%) amniotic fluid acetylcholinesterase, and 8 of 11 (73%) DNA microarray. There is also variation from the Management of Myelomeningocele Study with regard to body mass index (BMI) (1/11; 9% would offer surgery with BMIs higher than 35), maternal medical risk factors (surgery would be offered for controlled pregestational diabetes [3/10 (30%)]), hepatitis C with negative viral load (4/11 [36%]), and human immunodeficiency virus with an undetectable viral load (1/10 [10%] or an obstetric history [3/11 (27%)] would offer surgery with a history of preterm delivery on progesterone). Ten of 11 (91%) centers did not consider ventriculomegaly of 18 mm and 9 of 11 (82%) centers did not consider lack of leg movement as an exclusion criteria. Nuances in the perioperative and intraoperative management were also reported, including 5 of 11 (45%) use intraoperative echocardiography and alterations in postoperative tocolytics. CONCLUSION: Variation in practice patterns for offering and performing maternal-fetal surgery for myelomeningocele repair exists among centers. Ongoing evaluation of inclusion and exclusion criteria as well as operative techniques is warranted to ensure continued safety, effectiveness, and beneficence.

Penetrating head injuries in children due to BB and pellet guns: a poorly recognized public health risk.

OBJECT Nonpowder guns, defined as spring- or gas-powered BB or pellet guns, can be dangerous weapons that are often marketed to children. In recent decades, advances in compressed-gas technology have led to a significant increase in the power and muzzle velocity of these weapons. The risk of intracranial injury in children due to nonpowder weapons is poorly documented. METHODS A retrospective review was conducted at 3 institutions studying children 16 years or younger who had intracranial injuries secondary to nonpowder guns. RESULTS The authors reviewed 14 cases of intracranial injury in children from 3 institutions. Eleven (79%) of the 14 children were injured by BB guns, while 3 (21%) were injured by pellet guns. In 10 (71%) children, the injury was accidental. There was 1 recognized assault, but there were no suicide attempts; in the remaining 3 patients, the intention was indeterminate. There were no mortalities among the patients in this series. Ten (71%) of the children required operative intervention, and 6 (43%) were left with permanent neurological injuries, including epilepsy, cognitive deficits, hydrocephalus, diplopia, visual field cut, and blindness. CONCLUSIONS Nonpowder guns are weapons with the ability to penetrate a child's skull and brain. Awareness should be raised among parents, children, and policy makers as to the risk posed by these weapons.

Superficial siderosis of the central nervous system associated with incomplete dural closure following posterior fossa surgery: report of 3 cases.

This report reviews a series of 3 patients who developed superficial siderosis following posterior fossa operations in which dural closure was incomplete. In all 3 patients, revision surgery and complete duraplasty was performed to halt the progression of superficial siderosis. Following surgery, 2 patients experienced resolution of their CSF xanthochromia while 1 patient had reduced CSF xanthochromia. In this paper the authors also review the etiology, pathophysiology, diagnosis, and treatment of this condition. The authors suggest that posterior fossa dural patency and pseudomeningocele are risk factors for the latent development of superficial siderosis and recommend that revision duraplasty be performed in patients with posterior fossa pseudomeningoceles and superficial siderosis to prevent progression of the disease.

Repeat resective surgery in complex pediatric refractory epilepsy: lessons learned.

OBJECT Resection can sometimes offer the best chance of meaningful seizure reduction in children with medically intractable epilepsy. However, when surgery fails to achieve the desired outcome, reoperation may be an option. The authors sought to investigate outcomes following resective reoperation in pediatric patients with refractory epilepsy, excluding tumoral epilepsies. Differences in preoperative workup between surgeries are analyzed to identify factors influencing outcomes and complications in this complex group. METHODS Medical records were reviewed for all pediatric patients undergoing a repeat resective surgery for refractory epilepsy at the authors' institution between 2005 and 2012. Tumor and vascular etiologies were excluded. Preoperative evaluation and outcomes were analyzed for each surgery and compared. RESULTS Ten patients met all inclusion criteria. The median age at seizure onset was 4.5 months. Preoperative MRI revealed no lesion in 30%. Nonspecific gliosis and cortical dysplasia were the most common pathologies. The majority of preoperative workups included MRI, video-electroencephalography (EEG), and SISCOM. Intracranial EEG was performed for 60% for the first presurgical evaluation and 70% for the second evaluation. The goal of surgery was palliative in 4 patients with widespread cortical dysplasia. The final Engel outcome was Class I in 50%. The rate of favorable outcome (Engel Class I-II) was 70%. The complication rate for the initial surgery was 10%. However, the rate increased to 50% with the second surgery, and 3 of these 5 complications were pseudomeningoceles requiring shunt placement (2 of the 3 patients underwent hemispherotomy). CONCLUSIONS Resective reoperation for pediatric refractory epilepsy has a high rate of favorable outcome and should be considered in appropriate candidates, even as a palliative measure. Intracranial EEG monitoring should be considered on initial workup in cases where the results of imaging or EEG studies are ambiguous or conflicting. Epilepsy secondary to cortical dysplasia, especially if the dysplasia is not seen clearly on MRI, can be difficult to cure surgically. Therefore, in these cases, as large a resection as can be safely accomplished should be done, particularly when the goal is palliative. The rate of complications, particularly pseudomeningocele ultimately requiring shunt placement, is much higher following reoperation, and patients should be counseled accordingly.

Factors contributing to the yield of asymmetric bilateral implantation of intracranial electrodes.

OBJECTIVE: To determine the outcome of implanting fewer electrodes over the hemisphere with less supporting presurgical localizing data. METHODS: We retrospectively reviewed our epilepsy surgery database at Mayo Clinic, Rochester, Minnesota, between January 1, 1999, and December 31, 2011, to identify patients who had an asymmetric number of electrode contacts implanted in each hemisphere for seizure localization. We scored each presurgical noninvasive data point (0, 0.5, or 1) to predict the likelihood of identifying seizure onset in the hemisphere with fewer intracranial electrode contacts (HFEC). An aggregate score was obtained for each patient. RESULTS: Thirteen (37%) of 35 patients had HFEC-onset seizures on intracranial electroencephalography (iEEG). The following factors predicted HFEC-onset seizures: (1) temporal lobe epilepsy (p = 0.02); (2) interictal scalp electroencephalographic discharges at the HFEC (p = 0.04); and (3) both interictal and ictal scalp EEG discharges at the HFEC (p = 0.01). The median (range) aggregate score was 2 (1-3) for patients with HFEC-onset seizures recorded on iEEG and 1 (0-3) for patients without HFEC-onset seizures (p = 0.001). Using this scoring model, the odds ratio of identifying HFEC-onset seizures on iEEG was 6.4 for each one-point increment in the aggregate score. The area under the receiver operating characteristic curve for this model was 0.84, suggesting excellent ability of the aggregate score to discriminate between patients with and without HFEC-onset seizures on iEEG. SIGNIFICANCE: Implanting electrodes on the basis of limited supporting presurgical data may be useful in selected patients, especially those with temporal lobe epilepsy, interictal scalp discharges involving the HFEC, or both interictal and ictal scalp discharges involving the HFEC. In addition, our proposed scoring system may be helpful in selecting patients with complicated epilepsy for implantation of an asymmetric number of intracranial electrodes in the hemispheres.

Clinical outcomes of children and adults with central nervous system primitive neuroectodermal tumor.

Central nervous system primitive neuroectodermal tumors (CNS PNETs) predominantly occur in children and rarely in adults. Because of the rarity of this tumor, its outcomes and prognostic variables are not well characterized. The purpose of this study was to evaluate clinical outcomes and prognostic factors for children and adults with CNS PNET. The records of 26 patients (11 children and 15 adults) with CNS PNET from 1991 to 2011 were reviewed retrospectively. Disease-free survival (DFS) and overall survival (OS) were estimated with the Kaplan-Meier method, and relevant prognostic factors were analyzed. For the cohort, both the 5-year DFS and the OS were 46 %. For pediatric patients, the 5-year DFS was 78 %; for adult patients, it was 22 % (P = 0.004). Five-year OS for the pediatric and adult patients was 67 and 33 %, respectively (P = 0.07). With bivariate analysis including chemotherapy regimen (high dose vs. standard vs. nonstandard) or risk stratification (standard vs. high) and age, the increased risk of disease recurrence in adults persisted. A nonsignificant tendency toward poorer OS in adult patients relative to pediatric patients also persisted. High-dose chemotherapy with stem cell rescue was associated with a statistically significant improvement in OS and a tendency toward improved DFS, although the findings were mitigated when the effect of age was considered. Local recurrence was the primary pattern of treatment failure in both adults and children. Our results suggest that adult patients with CNS PNETs have inferior outcomes relative to the pediatric cohort. Further research is needed to improve outcomes for CNS PNET in populations of all ages.

Diagnostic outcome of surgical revision of intracranial electrode placements for seizure localization.

PURPOSE: We aimed to determine the yield of revising intracranially implanted electrodes and the factors contributing to the yield. METHODS: Patients were identified from the Mayo Clinic Epilepsy Surgery Database between 1997 and 2010. Twenty patients had revision of intracranial electrode placements because initial implantation did not localize seizure onset adequately. RESULTS: Seizures were captured in 18 of 20 patients who underwent intracranial electrode revision, of which 10 (55.6%) showed localized seizure onset that led to a surgical resection. Seizures were improved in 9 of 10 patients who underwent resection; of these, five were seizure free. The only factors found to be statistically significant in localizing ictal onset zone after revised implantation were prior focal scalp interictal discharges and an initial intracranial EEG showing ictal onset at the edge of the electrode grid. No permanent complication was associated with revised implantation, but one patient had transient apraxia of the right foot. CONCLUSIONS: Revised implantation could be useful in selected patients with inadequate seizure localization on initial intracranial EEG. Resective surgery was performed in 50% of patients who underwent revision of intracranial electrodes with the majority of these patients experiencing an improvement in seizure control.

Chronic subthreshold subdural cortical stimulation for the treatment of focal epilepsy originating from eloquent cortex.

Medically refractory epilepsy remains a major medical problem worldwide. Although some patients are eligible for surgical resection of seizure foci, a proportion of patients are ineligible for a variety of reasons. One such reason is that the foci reside in eloquent cortex of the brain and therefore resection would result in significant morbidity. This retrospective study reports our experience with a novel neurostimulation technique for the treatment of these patients. We identified three patients who were ineligible for surgical resection of the intracranially identified seizure focus because it resided in eloquent cortex, who underwent therapeutic trial of focal cortical stimulation delivered through the subdural monitoring grid. All three patients had a significant reduction in seizures, and two went on to permanent implantation, which resulted in long-term reduction in seizure frequency. In conclusion, this small case report provides some evidence of proof of concept of the role of targeted continuous neocortical neurostimulation in the treatment of medically refractory focal epilepsy, and provides support for ongoing investigations into this treatment modality.

Histologically proven, low-grade brainstem gliomas in children: 30-year experience with long-term follow-up at Mayo Clinic.

INTRODUCTION: To evaluate long-term overall survival (OS), progression-free survival (PFS), and outcomes in pathologically proven brainstem low-grade gliomas (BS-LGG) in children. METHODS: The Mayo Clinic tumor registry identified 48 consecutive children (≤20 y, 52% female) with biopsy-proven BS-LGG treated at Mayo Clinic between January 1971 and December 2004. Medical records were retrospectively reviewed. For analysis, patients were censored at the time of recurrence, death, or last follow-up. RESULTS: The median age at diagnosis was 12 years with a median follow-up of 6.0 years. The majority of tumors were grade I (69%) and pathology was consistent with an astrocytoma in the majority of patients (98%). Gross total resection was obtained in 4, subtotal in 17, and 27 patients were biopsied only. Postoperative radiotherapy (RT) was used in 29 patients. Median OS for the entire group was 14.8 years with a 1-, 5-, and 10-year OS of 85%, 67% and 59%, respectively. Median PFS for the entire group was 7.3 years. Improved survival was associated with undergoing resection versus biopsy-only with 5-year OS rates of 85% and 50% (P=0.002), respectively. A high proportion of patients (42%) had diffuse tumors and 13 patients (27%) had diffuse pontine gliomas (DPGs). DPGs had an OS of 1.8 years with a worse median PFS than non-DPGs (1.8 vs. 11.1 y; P=0.009). RT was used preferentially in patients with poor prognosis such as those who had a biopsy-only procedure (19/27) and DPGs (9/13). CONCLUSIONS: OS in this single institution retrospective study in pathologically proven BS-LGG with extensive follow-up displayed favorable long-term outcomes. Improved outcomes were associated with nondiffuse classification.

Seizure outcomes after corpus callosotomy for drop attacks.

BACKGROUND: Medically intractable epilepsy involving drop attacks can be difficult to manage and negatively affect quality of life. Most studies investigating the effect of corpus callosotomy (CC) on seizures have been limited, focusing on the pediatric population or drop seizures alone, with little attention to other factors influencing seizure outcome. OBJECTIVE: To assess seizure outcomes after CC in adults and children. METHODS: Retrospective analysis was performed on all patients who underwent CC (anterior two thirds, 1- or 2-stage complete) at our institution between 1990 and 2011. Change in frequency after CC was assessed for drop seizures and other seizure types. Multiple factors were evaluated for impact on seizure outcome. RESULTS: Fifty patients met inclusion criteria. The median age was 1.5 years at seizure onset and 17 years at time of surgery. Anterior two-thirds CC was performed in 28 patients, 1-stage complete in 17, and 2-stage complete in 5. All 3 groups experienced a significant decrease in drop seizures (P < .001, P < .001, and P = .020, respectively), with 40% experiencing complete resolution, and 64% dropping at least 1 frequency category. Other seizure types significantly decreased in anterior two-thirds CC and 1-stage complete (P = .0035, P = .001, respectively). Younger age at surgery correlated with better seizure outcomes (P = .043). CONCLUSION: CC for medically refractory generalizing epilepsy is effective for both drop seizures and other seizure types. CC should be considered soon after a patient has been deemed medically refractory because earlier age at surgery results in lower risk and better outcome.

The role of nocturnal polysomnography in assessing children with Chiari type I malformation.

OBJECTIVE: To evaluate nocturnal polysomnogram findings in children with suspected symptomatic Chiari type I malformation, correlate them with clinical and magnetic resonance imaging data and to determine if this information has value in clinical decision making process. METHODS: A retrospective review identified 24 children with type I Chiari malformation, presumed symptomatic who had undergone neurological assessment, cranial magnetic resonance imaging and nocturnal polysomnography. Perimedullary subarachnoid space effacement on the magnetic resonance studies and the magnitude of cerebellar tonsillar descent in relation to the McRae line were correlated with frequency of obstructive or central sleep apnea, number of cortical arousals and evidence of impaired vocal mobility on laryngoscopy. The Wilcoxon rank sum test was applied for continuous variables and the Fisher exact test for categorical variables. RESULTS: The median age of the subjects was 6 years. The findings from 16/24 subjects with perimedullary subarachnoid space effacement (effaced group) were compared with those of 8/24 in the non-effaced group. The central apnea index [1.5 (IQR 1-3.5) versus 0.5 (IQR 0-1.5)] and cortical arousal index [12 (IQR 10-19) versus 8 (IQR 6.5-9)] were significantly higher in the effaced group than in the non-effaced group (p=0.0376 and 0.0036 respectively). Greater descent of tonsils as measured by distance from the McRae line to the tonsil tip was associated with significantly higher central apnea index, total arousal index and respiratory event related arousals. Measurements of clivus-canal angle, Klauss index and pB-C2 line did not correlate with abnormalities on polysomnography. CONCLUSION: The central apnea and arousal indices derived from the nocturnal polysomnogram correlate well with magnetic resonance imaging findings of subarachnoid space effacement and degree of tonsillar herniation. In children with Chiari type I malformation, the nocturnal polysomnogram findings provides important information that aids in the decision making process about proceeding with surgical decompression.

Prognostic factors and survival patterns in pediatric low-grade gliomas over 4 decades.

BACKGROUND: This study reports changes in long-term survival after the introduction of modern imaging in pediatric patients with low-grade gliomas (LGGs). METHODS: Records from 351 consecutive pediatric patients diagnosed with LGG between 1970 and 2009 at Mayo Clinic Rochester were reviewed and divided into diagnosis before (group I: 1970 to 1989) and after (group II: 1990 to 2009) postoperative magnetic resonance imaging became regularly used in pediatric LGG. RESULTS: Median progression-free survival (PFS) and overall survival (OS) were not reached. Overall, 10-year PFS was 62% and OS was 90%. On multivariate analysis, improved PFS was associated with gross total resection (GTR; P<0.0001) and postoperative radiation therapy (RT; P<0.0001). In those undergoing less than GTR, PFS was improved with RT, nearing rates of patients receiving GTR (P=0.12). On multivariate analysis, higher OS was associated with GTR (P<0.0001) and pilocytic histology (P=0.03). Group II had fewer headaches, fewer sensory/motor symptoms, less postoperative RT, and more GTRs. OS and PFS were not different between the groups. CONCLUSIONS: This large series of pediatric LGG patients with long-term follow-up found no significant changes in OS or PFS over time. Overall, GTR was associated with improved OS and PFS. RT was associated with an improvement in PFS, with the greatest benefit seen in patients undergoing less than GTR.

Spinal stenosis frequent in children with multiple hereditary exostoses.

PURPOSE: Children with multiple hereditary exostoses (MHE) have numerous osteochondromas, with the most prominent lesions typically over the appendicular skeleton. A recent report noted a high rate of intracanal lesions in this patient population and recommended preventative spinal screening with magnetic resonance imaging (MRI) or computed tomography (CT). We sought to evaluate the prevalence of spinal stenosis from intracanal osteochondromas at our pediatric orthopedic center in order to evaluate if routine screening is warranted. METHODS: All pediatric patients treated for MHE were retrospectively identified. Records were reviewed to determine demographics, previous orthopedic surgery, and indication and results of axial spine imaging (CT or MRI). Imaging studies were reviewed to evaluate the presence of intracanal and compressive spinal lesions. RESULTS: Between 1990 and 2011, axial imaging was performed in nine patients with MHE due to concerns of pain, weakness, and/or dizziness. These patients had moderate disease involvement, with a mean of 4.9 previous orthopedic surgeries to address skeletal osteochondromas. Two patients with MHE had cervical spinal stenosis secondary to intracanal osteochondromas. Both children successfully underwent spinal decompression. Thus, of our MHE population undergoing axial imaging, 22 % were noted to have intracanal lesions. CONCLUSIONS: Our experience reveals a >20 % rate of compressive intracanal osteochondromas in MHE patients undergoing spinal imaging. These two patients represent 5 % of the MHE patients treated at our center. These lesions may be slow growing, and significant consequences can occur if not identified promptly. Thus, we confer that routine axial screening of the spinal canal may be warranted in these children.

Complications necessitating a return to the operating room following intradural spine surgery.

OBJECTIVE: To determine the incidence of and risk factors for cerebrospinal fluid (CSF), wound, and hematoma-related complications following intradural spine surgery. BACKGROUND: Complications of intradural spinal surgery requiring a return to the operating room lengthen hospital stay and increase cost as well as patient risk. Here we present our experience with complications in intradural spinal surgery. METHODS: Between 1993 and 2010, a total of 528 pediatric and adult patients who underwent biopsy and/or resection of intramedullary or extramedullary spinal lesions at Mayo Clinic-Rochester were evaluated. RESULTS: The overall complication rate in this series was 4.9%. Complications, such as neurologic worsening due to an etiology not able to be treated surgically, or medical complications, such as deep venous thrombosis, were not included in this study. The overall complication rates that were CSF-related, wound-related, hematoma-related, and miscellaneous were 3.0%, 1.1%, 0.6%, and 0.2% respectively. Complication rates decreased with age from 15.4% in 0- to 10-year-olds to 4.1% in 61- to 90-year-olds. Tumors represented the majority of pathology at 90.5%. The complication rate for patients who had prior treatment was higher at 6.9% compared with 4.7% in those who had no prior treatment (P = 0.5). Intramedullary tumors had a complication rate of 7.1% vs. 3.6% for extramedullary tumors (P = 0.14). Some patients (5.7%) had coexisting intracranial tumors at the time of their surgery but none had complications with intradural spine surgery. CONCLUSIONS: Complications of intradural spine surgery are most commonly CSF related, may decrease with increasing age of the patient, and are higher with intramedullary tumors.