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Lateral canthal advancement of the supraorbital margin

A new corrective technique in the treatment of coronal synostosis

Harold J. Hoffman and Gerard Mohr

✓ In coronal synostosis, in addition to fusion of the coronal suture, the frontosphenoidal and frontoethmoidal sutures are usually closed. A linear craniectomy along the coronal sutures does not affect the synostotic process at the base of the skull. The facility with which the supraorbital margin could be mobilized in Tessier's method of craniofacial repair suggested to us that we could easily modify our approach to coronal synostosis and advance the supraorbital margin, creating an artificial suture at the base of the skull and allowing for proper correction of this disorder. During the past 3 years, we have treated 15 patients with coronal synostosis by this technique, which we have termed lateral canthal advancement. The method of this form of surgical management and its results are discussed.

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Burak Sade, Gérard Mohr and Jean-Jacques Dufour

Object

Vascular complications of the surgery for vestibular schwannomas (VSs) can have devastating consequences; however, there is scant literature on the systematic analysis of the different types of complications. In this context, the authors of this study analyzed these complications, with particular interest in the role of surgical approach in their occurrence.

Methods

The charts of 391 patients who had undergone 413 procedures for VS during a 24-year period were reviewed retrospectively. A suboccipital retrosigmoid (RS) approach was used in 338 procedures, and the translabyrinthine (TL) route in 75. Postoperative hemorrhage or infarction was identified and stratified according to the complication type and surgical approach.

Postoperative vascular complications were encountered in 11 procedures (2.7%), and their incidence was the same for both the RS and TL approaches. Of these complications, eight were hemorrhagic (two cerebellopontine angle, one intracerebellar, and five epidural hematomas) and three were ischemic in nature. Five patients (45.4%) had a complete recovery, and four patients (36.4%) a partial recovery; two patients (18.2%) died. The overall procedure-related mortality rate was 0.5% (two of 413 procedures): 0.3% (one of 338 procedures) for the RS approach and 1.3% (one of 75 procedures) for the TL approach (p > 0.05).

Conclusions

In this study, the overall incidences of vascular complications in VS surgery were similar for the RS and TL approaches. Regardless of the preferred surgical route, this group of complications carries a significant risk of morbidity and therefore warrants special consideration in the management of VSs.

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Intraventricular hemorrhage from ruptured aneurysm

Retrospective analysis of 91 cases

Gerard Mohr, Gary Ferguson, Moe Khan, David Malloy, Reginald Watts, Brien Benoit and Bryce Weir

✓ Intraventricular hemorrhage (IVH) from aneurysm rupture is generally considered to be of grave prognostic significance. Ninety-one cases have been studied retrospectively from seven medical centers. The overall mortality rate was 64%. The dramatically poor condition of these patients leads to their rapid admission to the hospital. Eighty-seven percent were admitted on Day 0 or 1, and more than half were classified neurologically as Grade 4 or 5. A multiple regression analysis explained 56% of the variance in survival, using the variables of ventriculocranial ratio (VCR), day of admission, diastolic blood pressure, location of aneurysm, associated intracerebral hematoma, age, grade on admission, sex, and systolic blood pressure. No patient with a VCR of more than 0.25, as calculated from the initial computerized tomography (CT) scan, survived. No patient whose smallest VCR was 0.23 or more survived. This ratio can be simply measured with a millimeter ruler from the CT scan. Patients with IVH usually had enlarged ventricles, even initially. The overall results suggest that early management of intracranial hypertension should be more generally considered, although even when this was done the prognosis was still guarded. The timing of surgery was not an important determinant of outcome, although a significant number of patients died awaiting surgery.

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Burak Sade, Gérard Mohr, Donatella Tampieri and Arthur Rizzo

✓ An aneurysm completely included within a pituitary adenoma that lies inside the sella turcica is rare and challenging from both a diagnostic and treatment viewpoint. A 39-year-old woman presented with symptoms and signs of acromegaly. Magnetic resonance imaging revealed a pituitary macroadenoma, which was associated with an intrasellar aneurysm. Digital subtraction angiography confirmed the presence of the cavernous carotid artery aneurysm. Complete endovascular obliteration of the aneurysm was achieved using Guglielmi Detachable Coils and the patency of the internal carotid artery was maintained. The pituitary adenoma was resected subtotally via a transsphenoidal microsurgical approach 8 months later. Preoperative detection of a coexisting intrasellar aneurysm in a patient with a pituitary adenoma is mandatory to avoid life-threatening hemorrhagic complications. Endovascular coil placement is an effective treatment option when performed before the transsphenoidal removal of the adenoma.

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Zhong-Ping Chen, Daniel Yarosh, Yesenia Garcia, Donatella Tampieri, Gérard Mohr, Adrian Langleben and Lawrence C. Panasci

Adjuvant nitrosourea chemotherapy fails to prolong patient survival significantly as many tumors demonstrate resistance to these drugs. It has been documented in cell lines that O6-methylguanine-DNA methyltransferase (MGMT) plays an important role in chloroethylnitrosourea (CENU) drug resistance.

The authors evaluated MGMT expression in 22 glioma specimens by using an immunofluorescence assay and compared the results with clinical response of the patients to CENU-based chemotherapy.

The patients were treated with CENU after evidence of progressive disease following surgery and radiotherapy. Eight tumor samples had no detectable MGMT, whereas other samples had from 9989 to 982,401 molecules/nucleus. In one group (12 patients), the tumor decreased in size or was stable (effective group), whereas in the other group (10 patients), the tumor demonstrated continuous growth during chemotherapy (progressive group). The median time to progression (TTP) was 6.7 months with a median survival of 13 months. The Mer patients (MGMT < 60,000 molecules/nucleus) appeared to have more chance of stable disease or response to CENU therapy than the Mer+ patients (MGMT > 60,000 molecules/nucleus) (chi-square = 4.791, p = 0.0286). In patients with glioblastomas multiforme (GBMs), the TTP of Mer+ patients was shorter than that of Mer patients (t = 2.04, p = 0.049). As a corollary, the MGMT levels were significantly higher in GBM tumors from the progressive group than those from the effective group (t = -2.26, p = 0.029). The TTP and survival time in the effective GBM group were also longer than those in the progressive GBM group. However, there was no significant correlation between MGMT levels and either the survival time (r = 0.04, p = 0.8595) or TTP (r = 0.107, p = 0.6444).

Results from this study suggested that MGMT positivity is indicative of more aggressive disease that progresses more rapidly when exposed to CENU therapy. However, MGMT-negative tumors are not always sensitive to CENU agents, suggesting that other factors may also be important.

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Maria S. Li, Sandra Miller Portman, Akram Rahal, Gérard Mohr and Vijayabalan Balasingam

Object

Concerns about extreme peritumoral edema and its ensuing surgical and perioperative complications led the authors to use the bilateral fronto-orbito-nasal approach to remove midline anterior skull base meningiomas that were larger than 4 cm. The authors hypothesize that extreme vasogenic edema exemplified by finger-like hyperintensities extending into the bifrontal white matter and external capsule and/or the extreme capsule, coined the lion's mane sign (LMS), would help identify patients with a challenging postoperative course. They hypothesize that the LMS would better predict symptomatic postoperative cerebral edema than the edema index (EI).

Methods

This is an observational case series of 9 patients. The authors noted the grade, pathology, tumor volume, EI, and the presence or absence of the LMS in all tumors. They used the intensive unit care (ICU) length of stay as a nonspecific measure reflecting postoperative symptomatic cerebral edema. Comparisons of edema-related postoperative complications and the EI were made between patients with and without an LMS.

Results

Bifrontal hyperintensities, extending into at least three-eighths of the length of the external capsules on T2-weighted MRI, seen in 4 of 9 patients, portended a longer postoperative ICU stay. The presence of an LMS better predicted postoperative complications related to cerebral edema than tumor grade, pathology, volume, or EI.

Conclusions

The LMS predicts an increased duration of stay in the ICU after a bilateral fronto-orbito-nasal approach for resection of large and giant anterior skull base meningiomas. Furthermore, the LMS better predicted increased length of stay in the ICU than did the EI.

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Gérard Mohr, Burak Sade, Jean-Jacques Dufour and Jamie M. Rappaport

Object. Preservation of hearing has become a standard goal in selected patients undergoing surgery for a vestibular schwannoma (VS). This study was aimed at analyzing the role played by filling of the internal auditory canal (IAC) as well as those played by preoperative hearing quality, and tumor size in the postoperative preservation of serviceable hearing (SH).

Methods. Three hundred eighty-six patients with VS were treated. Hearing preservation was attempted in 128 cases (33.2%) by using intraoperative monitoring and following a retrosigmoid approach. The maximal extrameatal size of the tumor, its extension within the IAC, and pre- and postoperative hearing quality, according to the Gardner—Robertson classification, were evaluated. Preservation of SH was achieved in 24.2% of the 128 patients. With respect to tumor size, SH was preserved in 39% of 77 patients harboring a tumor 15 mm wide or smaller and in 2% of 51 patients with lesions 16 mm wide or larger (p < 0.001). With regard to filling of the IAC, among 63 patients harboring a tumor 15 mm or smaller, in whom magnetic resonance images were available, SH was preserved in 52.8% of 36 patients with partial filling and in 25.9% of 27 patients with complete filling (p = 0.032). Concerning preoperative hearing quality, in the patients with tumors 15 mm or smaller, SH was preserved in 46.5% of 43 patients with Gardner—Robertson Class I hearing and 29.4% of 34 patients with Class II hearing (p = 0.126). Both tumor size and the extent of IAC filling proved statistically significant in a multivariable analysis (p < 0.001 and p = 0.026, respectively).

Conclusions. Incomplete filling of the IAC and a tumor size of 15 mm or smaller are independent favorable factors in SH preservation. Excellent preoperative hearing appears to have a positive impact but does not have statistical significance. Intraoperative monitoring is useful in guiding the dissection; however, the surgeon's knowledge of topographical landmarks and meticulous surgical technique remain the essential factors of success.

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Brian Wheelock, Bryce Weir, Reginald Watts, Gerard Mohr, Moe Khan, Michael Hunter, Derek Fewer, Gary Ferguson, Felix Durity, Douglas Cochrane and Brien Benoit

✓ Intracerebral hematomas (ICH) from aneurysm rupture are not rare and can now be diagnosed easily and accurately by computerized tomography. The authors have collected 132 such cases from 11 medical centers. Of these patients, 38% died prior to discharge from the hospital. Seventy-eight percent of cases were admitted to the neurosurgical services on Day 0 or 1 after rupture of the aneurysm; of these patients, 15% died without surgery, 28% had surgery and died postoperatively, and 57% were operated on and survived. Mortality rates were increased in patients who were hypertensive, had poor neurological grades, showed evidence of brain herniation, or had larger clots. If the patient lived beyond the first few days and did not have brain herniation, the timing of surgery was not of great consequence, although there was a tendency toward lower morbidity in earlier surgery. This was true despite the fact that earlier operations were carried out on an initially sicker group of patients. Ischemic deterioration attributed to vasospasm occurred in 26% of cases; even when deaths at the acute stage were excluded, it was no more common in patients with early than in those with late surgery. Morbidity and mortality rates were prohibitively high in operations consisting solely of evacuation of ICH without clipping of the aneurysm. Parietal hematomas were particularly dangerous, while those in the temporal lobe were associated with the best outcome. Since it is impossible to predict survival with a high degree of reliability, even when the prognostic indicators are known, the authors recommend that patients with a significant ICH have it removed as soon as possible and that their ruptured aneurysm be clipped at the same time.

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Richard Leblanc, Jane L. Tyler, Gérard Mohr, Ernst Meyer, Mirko Diksic, Lucas Yamamoto, Laughlin Taylor, Serge Gauthier and Antoine Hakim

✓ Pre- and postoperative positron emission tomography (PET) was performed in six patients undergoing extracranial to intracranial bypass procedures for the treatment of symptomatic extracranial carotid occlusion. The six patients were all men, aged 52 to 68 years. Their symptoms included transient ischemic attacks (five cases), amaurosis fugax (two cases), and completed stroke with good recovery (one case). Positron emission tomography was performed within 4 weeks prior to surgery and between 3 to 6 months postoperatively, using oxygen-15-labeled CO, O2, and CO2 and fluorine-18-labeled fluorodeoxyglucose. Cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rates for oxygen and glucose (CMRO2 and CMRGlu), and the oxygen extraction fraction (OEF) were measured in both hemispheres. Preoperatively, compared to five elderly control subjects, patients had increased CBV, a decreased CBF/CBV ratio, and decreased CMRO2, indicating reduced cerebral perfusion pressure and depressed oxygen metabolism. The CBF was decreased in only one patient who had bilateral carotid occlusions; the OEF, CMRGlu, and CMRO2/CMRGlu and CMRGlu/CBF ratios were not significantly different from control measurements.

All bypasses were patent and all patients were asymptomatic following surgery. Postoperative PET revealed decreased CBV and an increased CBF/CBV ratio, indicating improved hemodynamic function. This was associated with increased CMRO2 in two patients in whom the postoperative OEF was also increased. The CMRGlu and CMRGlu/CBF ratio were increased in five patients. Changes in CBF and the CMRO2/CMRGlu ratio were variable. One patient with preoperative progressive mental deterioration, documented by serial neuropsychological testing and decreasing CBF and CMRO2, had improved postoperative CBF, CBV, and CMRO2 concomitant with improved neuropsychological functioning and oxygen hypometabolism. It is concluded that symptomatic carotid occlusion is associated with altered hemodynamic function. Cerebral revascularization results in decreased CBV, indicating improved hemodynamic reserve, but does not consistently improve oxygen metabolism.

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Nimodipine treatment in poor-grade aneurysm patients

Results of a multicenter double-blind placebo-controlled trial

Kenneth C. Petruk, Michael West, Gerard Mohr, Bryce K. A. Weir, Brien G. Benoit, Fred Gentili, Lew B. Disney, Moe I. Khan, Michael Grace, Renn O. Holness, Melinda S. Karwon, Robert M. Ford, G. Stuart Cameron, William S. Tucker, G. Barrie Purves, Jack D. R. Miller, K. Michael Hunter, Michael T. Richard, Felix A. Durity, Richard Chan, Lawrence J. Clein, Falah B. Maroun and Alain Godon

✓ A multicenter, randomized placebo-controlled double-blind trial of nimodipine in poor-grade aneurysm patients was carried out in 17 Canadian hospitals. Of 188 patients enrolled in the trial, 32 were excluded for protocol violations and two were excluded due to statistical considerations, leaving 154 patients for valid outcome analysis. Nimodipine treatment was associated with a significantly better outcome (p < 0.001): 21 (29.2%) of 72 nimodipine-treated patients had a good outcome at 3 months after subarachnoid hemorrhage (SAH) compared to eight (9.8%) of 82 placebo-treated patients. Delayed ischemic deficits from vasospasm alone were significantly less frequent in the nimodipine group (p < 0.05) with permanent deficits occurring in five nimodipine-treated patients (6.9%) and in 22 placebo-treated patients (26.8%). Improvement in the good outcome rate and reduction in delayed ischemic deficits from vasospasm alone occurred in both Grade 3 and 4 patients, with no difference between nimodipine- and placebo-treated patients being found in Grade 5 patients.

Repeat angiography after Day 4 was carried out in 124 patients. There was no significant difference in the incidence of moderate or severe diffuse spasm, which was seen in 64.3% of nimodipine-treated patients and 66.2% of placebo-treated patients. The authors conclude that nimodipine treatment in poor-grade patients with SAH results in an increase in the number of good outcomes and a reduction in the incidence of delayed neurological deterioration due to vasospasm. This effect occurs by a mechanism other than prevention of large-vessel spasm as visualized on angiography.