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Jennifer L. Quon, Ryan A. Grant and Michael L. DiLuna

OBJECT

Extradural decompression is a minimally invasive technique for treating Chiari malformation Type I (CM-I) that avoids the complications of dural opening. While there is no agreement on which surgical method is optimal, mounting evidence demonstrates that extradural decompression effectively treats clinical symptoms, with a minimal reoperation rate. Neurological symptoms such as headache may be related to obstructed flow of CSF, and one aspect of successful extradural decompression is improved CSF dynamics. In this series, the authors report on their use of phase-contrast cine flow MRI to assess CSF flow as well as satisfactory decompression.

METHODS

The authors describe their first surgical series of 18 patients with CM-I undergoing extradural decompression and correlate clinical improvement with radiological changes. Patients were categorized as having complete, partial, or no resolution of their symptoms. Posterior fossa area, cisterna magna area, and tonsillar herniation were assessed on T2-weighted MRI, whereas improvement of CSF flow was evaluated with phase-contrast cine flow MRI. All patients received standard pre- and postoperative MRI studies; 8 (44.4%) patients had pre- and postoperative phase-contrast cine, while the rest underwent cine studies only postoperatively.

RESULTS

All 18 patients presented with symptomatic CM-I, with imaging studies demonstrating tonsillar herniation ≥ 5 mm, and 2 patients had associated syringomelia. All patients underwent suboccipital decompression and C-1 laminectomy with splitting of the dura. Patients with complete resolution of their symptoms had a greater relative increase in cisterna magna area compared with those with only partial improvement (p = 0.022). In addition, in those with complete improvement the preoperative cisterna magna area was smaller than in those who had either partial (0.020) or no (0.025) improvement. Ten (91%) of the 11 patients with improved flow also had improvement in their symptoms. There was 1 postoperative complication of dysphagia and dysphonia. None of the patients have required a second operation.

CONCLUSIONS

Extradural decompression has the potential to be the first-line treatment for CM-I but has been lacking an objective measure by which to assess surgical success as well as the need for reoperation. An increase in the CSF spaces and improved CSF dynamics may be associated with resolution of clinical symptoms. Including cine imaging as part of routine pre- and postoperative evaluation can help identify which patients are most likely to benefit from surgery.

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Brian J. McHugh, Ryan A. Grant, Alyssa B. Zupon and Michael L. DiLuna

The etiology of os odontoideum has been debated in the literature since the condition was initially described. The authors present the case of a 4-year-old girl who was found to have an os odontoideum with atlantoaxial instability after a motor vehicle collision. Imaging performed 3 years earlier demonstrated an incompletely ossified, cartilaginous, orthotopic os separated from the body of the odontoid process at the level of the secondary ossification center with a short odontoid process. This case presents the earliest imaging demonstration of the presence of a congenital orthotopic os odontoideum at the secondary ossification center. The authors review the pertinent literature and propose that the etiology of os odontoideum is multifactorial and related to the embryology and vascular supply to the odontoid process.

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William R. Copeland, Grant W. Mallory, Brian A. Neff, Colin L. W. Driscoll and Michael J. Link

OBJECT

The following study was conducted to identify risk factors for a postoperative CSF leak after vestibular schwannoma (VS) surgery.

METHODS

The authors reviewed a prospectively maintained database of all patients who had undergone resection of a VS at the Mayo Clinic between September 1999 and May 2013. Patients who developed a postoperative CSF leak within 30 days of surgery were compared with those who did not. Data collected included patient age, sex, body mass index (BMI), tumor size, tumor side, history of prior tumor treatment, operative time, surgical approach, and extent of resection. Both univariate and multivariate regression analyses were performed to evaluate all variables as risk factors of a postoperative CSF leak.

RESULTS

A total of 457 patients were included in the study, with 45 patients (9.8%) developing a postoperative CSF leak. A significant association existed between increasing BMI and a CSF leak, with those classified as overweight (BMI 25–29.9), obese (BMI 30–39.9), or morbidly obese (BMI ≥ 40) having a 2.5-, 3-, and 6-fold increased risk, respectively. Patients undergoing a translabyrinthine (TL) approach experienced a higher rate of CSF leaks (OR 2.5, 95% CI 1.3–4.6; p = 0.005), as did those who had longer operative times (OR 1.04, 95% CI 1.02–1.07; p = 0.0006). The BMI, a TL approach, and operative time remained independent risk factors on multivariate modeling.

CONCLUSIONS

Elevated BMI is a risk factor for the development of a postoperative CSF leak following VS surgery. Recognizing this preoperatively can allow surgeons to better counsel patients regarding the risks of surgery as well as perhaps to alter perioperative management in an attempt to decrease the likelihood of a leak. Patients undergoing a TL approach or having longer operative times are also at increased risk of developing a postoperative CSF leak.

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Derek Yecies, Paul Graham Fisher, Samuel Cheshier, Michael Edwards and Gerald Grant

OBJECTIVE

Primarily metastatic juvenile pilocytic astrocytoma (JPA) is rare, likely representing 2%–3% of all cases of JPA. Due to the rarity of primarily metastatic JPA, there is currently no standard treatment paradigm and the long-term outcomes are not fully known. The goal of this case series was to add to the current understanding of this disease process.

METHODS

The authors searched a comprehensive database of pediatric patients with brain and spinal cord tumors treated at Lucile Packard Children’s Hospital from 1997 to 2016 and identified 5 patients with primarily metastatic JPA. A retrospective chart review was performed and details of the patients’ treatment and clinical course were recorded for further analysis.

RESULTS

For the 5 patients with primarily metastatic JPA, the mean follow-up period was 12.3 years. All patients in our series had biopsies or subtotal resections and upfront treatment. Three patients were treated with chemotherapy alone, one was treated with chemotherapy and radiotherapy, and one was treated with radiotherapy alone. Four patients had stable disease after initial treatment, and one patient had multiple episodes of progressive disease but underwent successful salvage therapy and has had stable disease for 19 years. One patient died of an intracerebral hemorrhage 10 years following initial radiation treatment believed to be secondary to radiation vasculopathy.

CONCLUSIONS

Evaluation of the entire neuraxis should be performed in all instances of initial JPA diagnosis to properly assess for primarily metastatic disease. Many patients with primarily metastatic JPA will have stable disease after upfront treatment, although the higher rate of stable disease found in this series relative to other reports is likely secondary to the small sample size.

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Eric Zimmerman, John Grant, W. Michael Vise, David Yashon and William E. Hunt

✓ Two patients with bursting fractures of the atlas vertebra are presented. The use of a halo apparatus as an effective alternative to bedrest and cervical traction in these patients is discussed. Polytomography was helpful in establishing an accurate diagnosis.

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Michael R. Fearnside and John M. F. Grant

✓ An acute necrotizing encephalitis due to herpes simplex virus may complicate craniotomy and cause death. Two such cases are reported and the subject reviewed. Early diagnosis is essential so that idoxuridine can be given and external surgical decompression contemplated.

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Srinivasan Mukundan, Herbert Fuchs, Michael J. Alexander and Gerald A. Grant

✓The authors report the first clinical use of 3-tesla dynamic contrast-enhanced magnetic resonance (MR) angiography for the diagnosis of a vascular malformation in a pediatric patient. The supply and drainage of an arteriovenous malformation were accurately demonstrated on MR angiography, which was performed without sedating the patient. This lesion was confirmed on catheter angiography, and definitive treatment via embolization was undertaken in a single session. The patient's therapeutic response will be followed with surveillance dynamic MR imaging.

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Abdullah H. Feroze, Graham G. Walmsley, Omar Choudhri, H. Peter Lorenz, Gerald A. Grant and Michael S. B. Edwards

Cranial bone repair is one of the oldest neurosurgical practices. Reconstructing the natural contours of the skull has challenged the ingenuity of surgeons from antiquity to the present day. Given the continuous improvement of neurosurgical and emergency care over the past century, more patients survive such head injuries, thus necessitating more than ever before a simple, safe, and durable means of correcting skull defects. In response, numerous techniques and materials have been devised as the art of cranioplasty has progressed. Although the goals of cranioplasty remain the same, the evolution of techniques and diversity of materials used serves as testimony to the complexity of this task. This paper highlights the evolution of these materials and techniques, with a particular focus on the implications for managing pediatric calvarial repair and emerging trends within the field.

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Chester J. Donnally III, Johnathon R. McCormick, Deborah J. Li, James A. Maguire Jr., Grant P. Barker, Augustus J. Rush III and Michael Y. Wang

OBJECTIVE

The purpose of this study was to assess the impact of certain demographics, social media usage, and physician review website variables for spine surgeons across Healthgrades.com (Healthgrades), Vitals.com (Vitals), and Google.com (Google).

METHODS

Through a directory of registered North American Spine Society (NASS) physicians, we identified spine surgeons practicing in Texas (107 neurosurgery trained, 192 orthopedic trained). Three physician rating websites (Healthgrades, Vitals, Google) were accessed to obtain surgeon demographics, training history, practice setting, number of ratings/reviews, and overall score (January 2, 2018–January 16, 2018). Using only the first 10 search results from Google.com, we then identified whether the surgeon had a website presence or an accessible social media account on Facebook, Twitter, and/or Instagram.

RESULTS

Physicians with either a personal or institutional website had a higher overall rating on Healthgrades compared to those who did not have a website (p < 0.01). Nearly all spine surgeons had a personal or institutional website (90.3%), and at least 1 accessible social media account was recorded for 43.5% of the spine surgeons in our study cohort (39.5% Facebook, 10.4% Twitter, 2.7% Instagram). Social media presence was not significantly associated with overall ratings across all 3 sites, but it did significantly correlate with more comments on Healthgrades. In multivariable analysis, increasing surgeon age was significantly associated with a lower overall rating across all 3 review sites (p < 0.05). Neurosurgeons had higher overall ratings on Vitals (p = 0.04). Longer wait times were significantly associated with a lower overall rating on Healthgrades (p < 0.0001). Overall ratings from all 3 websites correlated significantly with each other, indicating agreement between physician ratings across different platforms.

CONCLUSIONS

Longer wait times, increasing physician age, and the absence of a website are indicative of lower online review scores for spine surgeons. Neurosurgery training correlated with a higher overall review score on Vitals. Having an accessible social media account does not appear to influence scores, but it is correlated with increased patient feedback on Healthgrades. Identification of ways to optimize patients’ perception of care are important in the future of performance-based medicine.

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Kathleen J. Helton, Michael Edwards, R. Grant Steen, Thomas E. Merchant, Mark V. Sapp, Frederick A. Boop and James Langston

Object. After the resection of brain tumors in pediatric patients, it can be difficult to differentiate recurrent tumor from treatment effects. Although late-delayed reactions are thought to be permanent, in this study the authors sought to characterize transient brain lesions (TBLs) in the late-delayed period that completely resolved without imaging or neurological sequelae.

Methods. In a retrospective review of an institutional neuroimaging brain tumor database, 11 patients were identified who met the imaging criteria (transient T2-weighted hyperintense enhancing lesions outside of the tumor bed, which occurred after radiation and/or chemotherapy) and had undergone three-dimensional dosimetry; their radiographic, clinical, and radiation-dosimetry results were analyzed. In the 11 patients who had been treated with multiple protocols 17 loci of abnormality, including 43 discrete, asymptomatic TBLs, were detected. The median TBL diameter was 1 cm or smaller, without mass effect or necrosis, and occurred 10 months after radiation therapy, 11 months after chemotherapy, resolved by 3 months, and occurred within the high-dose radiation treatment volume (median 55.8 Gy). The findings from extended follow up revealed the development of additional permanent complications of radiation therapy within the radiation port in five of the 11 patients.

Conclusions. A benign form of treatment-induced brain injury in children, TBLs should be treated using short-interval follow up. When these lesions are identified as a result of their characteristic imaging features, location, and temporal course, TBLs may be clearly distinguished from recurrent tumor or radiation necrosis and do not require biopsy. Further studies are needed to determine whether patients with TBLs are at an increased risk of developing more severe treatment-related brain injury.