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Roukoz B. Chamoun, Claudia S. Robertson and Shankar P. Gopinath

Object

A Glasgow Coma Scale (GCS) score of 3 on presentation in patients with severe traumatic brain injury due to blunt trauma has been recognized as a bad prognostic factor. The reported mortality rate in these patients is very high, even approaching 100% in the presence of fixed and dilated pupils in some series. Consequently, there is often a tendency to treat these patients less aggressively because of the low expectations for a good recovery. In this paper, the authors' purpose is to report their experience in the management of this patient population, analyzing the mortality rate, prognostic factors, and functional outcome of survivors.

Methods

The authors performed a retrospective review of patients who presented between 1997 and 2007 with blunt head trauma and a GCS score of 3. Demographics, mechanism of injury, examination, blood alcohol level, associated injury, intracranial pressure (ICP), surgical procedures, and outcome were all recorded.

Results

A total of 189 patients met the inclusion criteria and were included in this study. The overall mortality rate was 49.2%. At the 6-month follow-up, 13.2% of the entire series achieved a good functional outcome (Glasgow Outcome Scale [GOS] score of 1 or 2).

The patient population was then divided into 2 groups: Group 1 (patients who survived [96]) and Group 2 (patients who died [93]). Patients in Group 1 were younger (mean 33.3 ± 12.8 vs 40.3 ± 16.97 years; p = 0.002) and had lower ICP on admission (mean 16.3 ± 11.1 vs 25.7 ± 12.7 mm Hg; p < 0.001) than those in Group 2. The difference between the 2 groups regarding sex, mechanism of injury, hypotension on admission, alcohol, surgery, and associated injuries was not statistically significant.

The presence of bilateral fixed, dilated pupils was found to be associated with the highest mortality rate (79.7%). Although not statistically significant because of the sample size, pupil status was also a good predictor of the functional outcome at the 6-month follow-up; a good functional outcome (GOS Score 1 or 2) was achieved in 25.5% of patients presenting with bilateral reactive pupils, and 27.6% of patients presenting with a unilateral fixed, dilated pupil, compared with 7.5% for those presenting with bilateral fixed, nondilated pupils, and 1.4% for patients with bilateral fixed, dilated pupils.

Conclusions

Overall, 50.8% of patients survived their injury and 13.2% achieved a good functional outcome after at 6 months of follow-up (GOS Score 1 or 2). Age, ICP on admission, and pupil status were found to be significant predictive factors of outcome. In particular, pupil size and reactivity appeared to be the most important prognostic factor since the mortality rate was 23.5% in the presence of bilateral reactive pupils and 79.7% in the case of bilateral fixed, dilated pupils. The authors believe that patients having suffered traumatic brain injury and present with a GCS score of 3 should still be treated aggressively initially since a good functional outcome can be obtained in some cases.

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Hassan H. Amhaz, Roukoz B. Chamoun, Steven G. Waguespack, Komal Shah and Ian E. McCutcheon

Rathke cleft cysts (RCCs) are benign cystic lesions of the sella that arise from the remnants of Rathke pouch. Although most are asymptomatic, symptoms can result from mass effect and commonly include headache, endocrinopathy, or visual field disturbance. Although asymptomatic patients undergo conservative treatment, patients with symptoms are typically treated surgically. The authors report 9 patients with symptomatic cystic sellar lesions and imaging characteristics consistent with an RCC; in all cases there was spontaneous involution of the lesions, and in 5 of 7 patients presenting with headache the symptom resolved. Spontaneous involution of an RCC may be more common than the paucity of prior reports would suggest, especially because the natural history of both symptomatic and asymptomatic RCCs is poorly understood. The potential for spontaneous involution, together with the clinical course of the patients reported here, supports a conservative approach for patients with symptomatic RCCs presenting solely with headache.

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Kyle A. Smith, John D. Leever, Phillip D. Hylton, Paul J. Camarata and Roukoz B. Chamoun

OBJECTIVE

Meningioma consistency, firmness or softness as it relates to resectability, affects the difficulty of surgery and, to some degree, the extent of resection. Preoperative knowledge of tumor consistency would affect preoperative planning and instrumentation. Several methods of prediction have been proposed, but the majority lack objectivity and reproducibility or generalizability to other surgeons. In a previous pilot study of 20 patients the authors proposed a new method of prediction based on tumor/cerebellar peduncle T2-weighted imaging intensity (TCTI) ratios in comparison with objective intraoperative findings. In the present study they sought validation of this method.

METHODS

Magnetic resonance images from 100 consecutive patients undergoing craniotomy for meningioma resection were evaluated preoperatively. During surgery a consistency grade was prospectively applied to lesions by the operating surgeon, as determined by suction and/or cavitron ultrasonic surgical aspirator (CUSA) intensity. Consistency grades were A, soft; B, intermediate; and C, fibrous. Using T2-weighted MRI sequences, TCTI ratios were calculated. Analysis of the TCTI ratios and intraoperative tumor consistency was completed with ANOVA and receiver operating characteristic curves.

RESULTS

Of the 100 tumors evaluated, 50 were classified as soft, 29 as intermediate, and 21 as firm. The median TCTI ratio for firm tumors was 0.88; for intermediate tumors, 1.5; and for soft tumors, 1.84. One-way ANOVA comparing TCTI ratios for these groups was statistically significant (p < 0.0001). A single cutoff TCTI value of 1.41 for soft versus firm tumors was found to be 81.9% sensitive and 84.8% specific.

CONCLUSIONS

The authors propose this T2-based method of tumor consistency prediction with correlation to objective intraoperative consistency. This method is quantifiable and reproducible, which expands its usability. Additionally, it places tumor consistency on a graded continuum in a clinically meaningful way that could affect preoperative surgical planning.

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Roukoz Chamoun, Dima Suki, Shankar P. Gopinath, J. Clay Goodman and Claudia Robertson

Object

Authors of several studies have implied a key role of glutamate, an excitatory amino acid, in the pathophysiology of traumatic brain injury (TBI). However, the place of glutamate measurement in clinical practice and its impact on the management of TBI has yet to be elucidated. The authors' objective in the present study was to evaluate glutamate levels in TBI, analyzing the factors affecting them and determining their prognostic value.

Methods

A prospective study of patients with severe TBI was conducted with an inclusion criterion of a Glasgow Coma Scale score ≤ 8 within 48 hours of injury. Invasive monitoring included intracranial pressure measurements, brain tissue PO2, jugular venous O2 saturation, and cerebral microdialysis. Patients received standard care including mass evacuation when indicated and treatment of elevated intracranial pressure values. Demographic data, CT findings, and outcome at 6 months of follow-up were recorded.

Results

One hundred sixty-five patients were included in the study. Initially high glutamate values were predictive of a poor outcome. The mortality rate was 30.3% among patients with glutamate levels > 20 μmol/L, compared with 18% among those with levels ≤ 20 μmol/L.

Two general patterns were recognized: Pattern 1, glutamate levels tended to normalize over the monitoring period (120 hours); and Pattern 2, glutamate levels tended to increase with time or remain abnormally elevated. Patients showing Pattern 1 had a lower mortality rate (17.1 vs 39.6%) and a better 6-month functional outcome among survivors (41.2 vs 20.7%).

Conclusions

Glutamate levels measured by microdialysis appear to have an important role in TBI. Data in this study suggest that glutamate levels are correlated with the mortality rate and 6-month functional outcome.

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Roukoz B. Chamoun, William E. Whitehead, Daniel J. Curry, Thomas G. Luerssen and Andrew Jea

Object

The use of C-1 lateral mass screws provides an alternative to C1–2 transarticular screws in the pediatric population. However, the confined space of the local anatomy and unfamiliarity with the technique may make the placement of a C-1 lateral mass screw more challenging, especially in the juvenile or growing spine.

Methods

A CT morphometric analysis was performed in 76 pediatric atlases imaged at Texas Children's Hospital from October 1, 2007 until April 30, 2008. Critical measurements were determined for potential screw entry points, trajectories, and lengths, with the goal of replicating the operative technique described by Harms and Melcher for adult patients.

Results

The mean height and width for screw entry on the posterior surface of the lateral mass were 2.6 and 8.5 mm, respectively. The mean medially angled screw trajectory from an idealized entry point on the lateral mass was 16° (range 4 to 27°). The mean maximal screw depth from this same ideal entry point was 20.3 mm. The overhang of the posterior arch averaged 6.3 mm (range 2.1–12.4 mm). The measurement between the left- and right-side lateral masses was significantly different for the maximum medially angled screw trajectory (p = 0.003) and the maximum inferiorly directed angle (p = 0.045). Those measurements in children < 8 years of age were statistically significant for the entry point height (p = 0.038) and maximum laterally angled screw trajectory (p = 0.025) compared with older children. The differences between boys and girls were statistically significant for the minimum screw length (p = 0.04) and the anterior lateral mass height (p < 0.001).

Conclusions

A significant variation in the morphological features of C-1 exists, especially between the left and right sides and in younger children. The differences between boys and girls are clinically insignificant. The critical measurement of whether the C-1 lateral mass in a child could accommodate a 3.5-mm-diameter screw is the width of the lateral mass and its proximity to the vertebral artery. Only 1 of 152 lateral masses studied would not have been able to accommodate a lateral mass screw. This study reemphasizes the importance of a preoperative CT scan of the upper cervical spine to assure safe and effective placement of the instrumentation at this level.

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Roukoz B. Chamoun, Michel E. Mawad, William E. Whitehead, Thomas G. Luerssen and Andrew Jea

Object

Currently, no diagnostic or treatment standards exist for extracranial carotid artery dissection (CAD) in children after trauma. The purpose of this study was to review and describe the characteristics, diagnosis, and treatment of this rather uncommon sequelae of pediatric trauma.

Methods

A systematic review of the literature was performed to examine the pertinent studies of traumatic extracranial carotid artery (CA) injuries in children.

Results

No randomized trials were identified; however, 19 case reports or small case series consisting of 34 pediatric patients were found in the literature. The diagnosis of CAD was made in 33 of 34 patients only after the onset of ischemic symptomatology. Twenty-four of 34 patients underwent cerebral angiography to confirm diagnosis; MR angiography affirmed the diagnosis in 6 of 34 patients. There was little published experience with CA ultrasonography or CT angiography for diagnosis. Thirty of 34 patients were treated with medical therapy or observation; 2 of 4 patients treated with observation alone died. There was little experience with open surgical treatment of CAD in the pediatric population, and there were no studies on the endovascular treatment of traumatic CAD in children. The literature does not support anticoagulation therapy over antiplatelet therapy.

Conclusions

As a result of this review of the literature, the authors propose the algorithms for the evaluation and treatment of traumatic extracranial CADs in children. These recommendations include utilizing MR angiography as a screening tool in cases in which the clinical suspicion of CAD is high, using conventional cerebral angiography to confirm the diagnosis, implementing antiplatelet therapy as initial medical management, and reserving endovascular stenting in cases of failed medical treatment.

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Anthony M. Alvarado, Kyle A. Smith and Roukoz B. Chamoun

Glioependymal cysts are rare congenital lesions of the central nervous system. Reported surgical treatments of these lesions have varied and yielded mixed results, and the optimal surgical strategy is still controversial. The authors here report the clinical and surgical outcomes for three adult patients successfully treated with neuroendoscopic fenestration into the ventricular system. The patients had presented with symptomatic glioependymal cysts in the period from 2013 to 2016 at the authors’ institution. All underwent minimally invasive neuroendoscopic fenestration of the glioependymal cyst into the lateral ventricle via a stereotactically guided burr hole. Presenting clinical and radiological findings, operative courses, and postintervention outcomes were evaluated.

All three patients initially presented with symptoms related to regional mass effect of the underlying glioependymal cyst, including headaches, visual disturbances, and hemiparesis. All patients were successfully treated with endoscopic fenestration of the cyst wall into the lateral ventricle, where the wall was thinnest. Postoperatively, all patients reported improvement in their presenting symptoms, and neuroimaging demonstrated decompression of the cyst. Clinical follow-up ranged from 4 months to 5 years without evidence of reexpansion of the cyst or shunt requirement.

Compared to open resection and shunting of the cyst contents, minimally invasive endoscopic fenestration of a glioependymal cyst into the ventricular system is a safe and effective surgical option. This approach is practical, is less invasive than open resection, and appears to provide a long-term solution.

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Roukoz B. Chamoun, Vikram V. Nayar and Daniel Yoshor

Accurate localization of the epileptogenic zone is of paramount importance in epilepsy surgery. Despite the availability of noninvasive structural and functional neuroimaging techniques, invasive monitoring with subdural electrodes is still often indicated in the management of intractable epilepsy. Neuronavigation is widely used to enhance the accuracy of subdural grid placement. It allows accurate implantation of the subdural electrodes based on hypotheses formed as a result of the presurgical workup, and can serve as a helpful tool for resection of the epileptic focus at the time of grid explantation. The authors describe 2 additional simple and practical techniques that extend the usefulness of neuronavigation in patients with epilepsy undergoing monitoring with subdural electrodes. One technique involves using the neuronavigation workstation to merge preimplantation MR images with a postimplantation CT scan to create useful images for accurate localization of electrode locations after implantation. A second technique involves 4 holes drilled at the margins of the craniotomy at the time of grid implantation; these are used as fiducial markers to realign the navigation system to the original registration and allow navigation with the merged image sets at the time of reoperation for grid removal and resection of the epileptic focus. These techniques use widely available commercial navigation systems and do not require additional devices, software, or computer skills. The pitfalls and advantages of these techniques compared to alternatives are discussed.

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Robert H. Rosenwasser

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Roukoz Chamoun and William T. Couldwell

Purely intraventricular craniopharyngiomas are rare and pose particular surgical challenges. The two main surgical approaches to these lesions based in the anterior third ventricle are the frontal transventricular approach (through a transcortical or transcallosal approach) and the trans–lamina terminalis approach. The authors note that the pituitary stalk in many of these cases is located in a normal position, which suggests that the third ventricular floor is intact. In such cases, the senior author chooses an approach to avoid disruption of the floor of the third ventricle. Specifically, a traditional frontotemporal approach is not used; we have found that in such cases, a frontal transventricular approach through the usually dilated foramen of Monro provides an optimal visualization of the tumor while minimizing the risks of injury to the hypothalamus and pituitary stalk. The endoscope can be very helpful in exploring blind angles, hidden from the microscopic view. Recognition of this rare location variant of craniopharyngioma is helpful in preoperative planning in an effort to reduce hypothalamic pituitary axis damage. Two patients presenting with craniopharyngiomas that were entirely intraventricular are shown in the video. The patients underwent removal of their tumors without incurring new long-term endocrine deficits.

The video can be found here: http://youtu.be/VFlhm_lsrGY.