Enhancement of the subtemporal approach by partial posterosuperior petrosectomy with hearing preservation

BACKGROUND

The microsurgical management of aneurysms in the interpeduncular and ambient cisterns remains challenging. The classic subtemporal approach has several limitations.

OBJECTIVE

To present a modification of this approach that allows for broader exposure with hearing preservation.

METHODS

We retrospectively reviewed our clinical database between August 2007 and February 2012 for all patients who underwent a modified subtemporal partial posterosuperior petrosectomy. Clinical data, complications, and postoperative head computed tomography (CT) scans were analyzed. Improvement in the angle of view acquired by the new approach was measured using the OsiriX 3-D rendering software and was compared with that obtained from the subtemporal approach. Similar methods were used to study improvement in the angle of view in head CT scans of randomly selected control patients.

RESULTS

Five patients underwent a modified subtemporal approach for posterior circulation aneurysm clipping. All patients were women with a mean age of 49.8 years. Mean aneurysm size was 5.75 mm. Mean improvement in the angle of view was 17.52° in the study group (n = 5) and 11.7° in the control group (n = 10). Hearing was completely preserved in 3 patients. One patient had a subclinical conductive hearing loss, and 1 patient was not assessed formally at follow-up, but had no hearing concerns. No neurological sequelae were recorded.

CONCLUSION

Our modified subtemporal approach appears to be safe and provides an increased angle of view with minimal additional operative time and with low risk to hearing. This approach may expand this surgical corridor and reduce the need for temporal lobe retraction.

De novo large fusiform posterior circulation intracranial aneurysm presenting with subarachnoid hemorrhage 7 years after therapeutic internal carotid artery occlusion: case report and review of the literature

BACKGROUND AND IMPORTANCE

Although the use of proximal artery occlusion, or hunterian ligation, for the treatment of intracranial aneurysms has decreased greatly over the past decades, this approach still finds use for certain giant and complex aneurysms. The main risks of artery sacrifice are ischemic complications but also, although rare, de novo aneurysm formation. We present here a case of de novo formation of a large fusiform basilar artery aneurysm 7 years after internal carotid artery occlusion.

CLINICAL PRESENTATION

A 17-year-old male patient with a history of a giant right cavernous aneurysm treated 7 years earlier with right-sided endovascular internal carotid artery occlusion presented to our institution with a thunderclap headache. At the time of initial evaluation, the patient was neurologically intact and imaging revealed a 22 × 10-mm fusiform aneurysm of the distal basilar artery with mass effect on the adjacent pons as well as a small amount of subarachnoid and intraventricular blood. Complete occlusion of the right internal carotid artery was demonstrated with retrograde filling of the right middle cerebral artery from the enlarged right posterior communicating artery. The patient was subsequently treated with hunterian occlusion of the basilar artery below anterior inferior cerebellar arteries. A superficial temporal artery to middle cerebral artery bypass was performed on the right side before this occlusion.

CONCLUSION

Further studies on the epidemiology of de novo aneurysms after carotid artery occlusion are warranted. Patients at higher risk of the development of intracranial aneurysms should be followed aggressively after hunterian ligation, and the possibility of an extracranial-intracranial bypass should be discussed.

Comparison of Intraoperative Portable CT Scanners in Skull Base and Endoscopic Sinus Surgery: Single Center Case Series

Precise and safe management of complex skull base lesions can be enhanced by intraoperative computed tomography (CT) scanning. Surgery in these areas requires real-time feedback of anatomic landmarks. Several portable CT scanners are currently available. We present a comparison of our clinical experience with three portable scanners in skull base and craniofacial surgery. We present clinical case series and the participants were from the Northwestern Memorial Hospital. Three scanners are studied: one conventional multidetector CT (MDCT), two digital flat panel cone-beam CT (CBCT) devices. Technical considerations, ease of use, image characteristics, and integration with image guidance are presented for each device. All three scanners provide good quality images. Intraoperative scanning can be used to update the image guidance system in real time. The conventional MDCT is unique in its ability to resolve soft tissue. The flat panel CBCT scanners generally emit lower levels of radiation and have less metal artifact effect. In this series, intraoperative CT scanning was technically feasible and deemed useful in surgical decision-making in 75% of patients. Intraoperative portable CT scanning has significant utility in complex skull base surgery. This technology informs the surgeon of the precise extent of dissection and updates intraoperative stereotactic navigation.

Ruptured spinal artery aneurysm associated with coarctation of the aorta

BACKGROUND

Spinal artery aneurysms associated with aortic coarctation are exceptionally rare, with only eight cases reported in the literature that we are aware of, and treatment of the aneurysm described only in one of them. Aortic coarctation often results in an aberrant collateral circulation with hyperdynamic flow and potential spinal artery aneurysm formation, growth, and rupture. Microsurgical, interventional, and medical management of these lesions can be challenging and has rarely been reported. Complication avoidance requires thorough knowledge of the clinical presentation of the disease, the hemodynamic factors involved, and the therapeutic tools available.

CASE DESCRIPTION

A 59-year-old woman with a previously undiagnosed isthmic coarctation of the aorta presented with subarachnoid hemorrhage. A 7-mm wide-necked, saccular spinal artery aneurysm was identified as the source of the hemorrhage and was subsequently successfully coiled through a transbrachial access route. After rehabilitation, the patient returned to her asymptomatic neurologic baseline, and underwent successful surgical repair of the aortic coarctation with placement of an interposition graft.

CONCLUSIONS

Spinal artery aneurysms induced by aortic coarctation are rare and complex entities. They pose unique surgical and medical challenges. Securing the aneurysm should be prioritized specifically in cases of subarachnoid hemorrhage. Blood pressure should be closely monitored and balanced to reduce the risk of rehemorrhage and at the same time allow for sufficient end-organ perfusion.

Aspirin use or reduced platelet activity predicts craniotomy after intracerebral hemorrhage

BACKGROUND

Craniotomy is potentially life-saving in selected patients with intracerebral hemorrhage (ICH). Aside from specific scenarios (cerebellar hemorrhage with hydrocephalus, midline shift from an accessible lesion, etc.) the indications for surgical decompression are controversial. Based on the earlier work that aspirin and reduced platelet activity are associated with larger hemorrhage size and hemorrhage growth, we tested the hypothesis that aspirin or reduced platelet activity would be associated with increased odds of craniotomy, likely through hemorrhage growth.

METHODS

We prospectively identified patients with spontaneous ICH and routinely measured platelet activity on admission. Patients were prospectively tracked, and outcomes were obtained with the modified Rankin Scale (mRS).

RESULTS

There were 187 patients in the sample. Craniotomy (N = 32, 17%) was associated with a higher initial ICH volume (37.9 [20-63] vs. 12 [5-24] ml, P < 0.001) and location (P = 0.005). In multivariate logistic regression, after controlling for ICH volume and location, any known aspirin use (OR 3.4, 95% CI 1.1-10.4, P = 0.03), platelet activity ≤550 aspirin reaction units (OR 3.1, 95% CI 1.05-9.3, P = 0.04), or an elevated PFA-EPI closure time (OR 3.2, 95% CI 1.02-10.3, P = 0.04) were associated with increased odds of craniotomy. Craniotomy was not associated with mRS at 14 days, 28 days, or 3 months.

CONCLUSIONS

After correction for ICH volume and location, aspirin use or reduced platelet activity was associated with similar increased odds for craniotomy.

Moyamoya disease: functional and neurocognitive outcomes in the pediatric and adult populations

OBJECT

Moyamoya disease is an occlusive cerebrovascular disorder commonly resulting in neurocognitive impairment. The cognitive outcome parameters commonly affected are intelligence, memory, executive function, and quality of life. In this paper, the authors review the existing literature on cognitive and clinical outcomes in adult and pediatric moyamoya populations separately.

METHODS

A systematic review of the cognitive and clinical outcome literature was performed using the PubMed/MEDLINE database. Outcomes data were contrasted between adult and pediatric populations.

RESULTS

Intelligence is the main cognitive outcome parameter affected in pediatric patients with moyamoya disease, whereas adults most commonly suffer from executive function impairment. Memory has not been studied sufficiently in pediatric patients, and its dysfunction in the adult population remains controversial. Quality of life has not been studied appropriately in either population. Surgical revascularization is the only beneficial treatment option, and a combination of direct and indirect bypass techniques has shown benefit, but the impact on the above-mentioned parameters has not been sufficiently elucidated.

CONCLUSIONS

Moyamoya disease affects the cognition and daily function in pediatric patients to a greater extent than in adult patients. Due to the rarity of the disease, there is a distinct lack of high-level evidence regarding cognitive and clinical outcomes.

Early platelet transfusion improves platelet activity and may improve outcomes after intracerebral hemorrhage

BACKGROUND

In patients with acute intracerebral hemorrhage (ICH), reduced platelet activity on admission predicts hemorrhage growth and poor outcomes. We tested the hypotheses that platelet transfusion improves measured platelet activity. Further, we hypothesized that earlier treatment in patients at high risk for hemorrhage growth and poor outcome would reduce follow-up hemorrhage size and poor clinical outcomes.

METHODS

We prospectively identified consecutive patients with ICH who had reduced platelet activity on admission and received a platelet transfusion. We defined high-risk patients as per a previous publication, reduced platelet activity, or known anti-platelet therapy (APT) and the diagnostic CT within 12 h of symptom onset. Platelet activity was measured with the VerifyNow-ASA (Accumetrics, CA), ICH volumes on CT with computerized quantitative techniques, and functional outcomes with the modified Rankin Scale (mRS) at 3 months.

RESULTS

Forty-five patients received a platelet transfusion with an increase in platelet activity from 472 ± 50 (consistent with an aspirin effect) to 561 ± 92 aspirin reaction units (consistent with no aspirin effect, P < 0.001). For high-risk patients, platelet transfusion within 12 h of symptom onset, as opposed to >12 h, was associated with smaller follow-up hemorrhage size (8.4 [3-17.4] vs. 13.8 [12.3-62.5] ml, P = 0.04) and increased odds of independence (mRS < 4) at 3 months (11 of 20 vs. 0 of 7, P = 0.01). There were similar results for patients with known APT.

CONCLUSIONS

In patients at high risk for hemorrhage growth and poor outcome, early platelet transfusion improved platelet activity assay results and was associated with smaller final hemorrhage size and more independence at 3 months.

The effect of call on neurosurgery residents' skills: implications for policy regarding resident call periods

Object

Although fatigue and its effects on surgical proficiency have been an actively researched area, previous studies have not examined the effect of fatigue on neurosurgery residents specifically. This study aims to quantify the effect of fatigue on the psychomotor and cognitive skills of neurosurgery residents.

Methods

Seven neurosurgery residents performed a minimum of 3 and a maximum of 4 sessions of 6 surgical exercises precall and postcall. The simulation exercises were designed to measure a surgeon's cognitive abilities, such as memory and attention, while performing simulated surgical tasks and exercises that have been previously validated in several studies, including studies measuring the impact of fatigue on general surgery residents. Each exercise measured tool-movement smoothness, time elapsed, and cognitive errors. The change in surgical skills in precall and postcall conditions was assessed by means of an ANOVA, with p < 0.05 considered statistically significant.

Results

The neurosurgery residents did not show a statistically significant difference in their surgical skills between the pre- and postcall states (p < 0.3, p < 0.4, and p < 0.2 for movement smoothness, time elapsed, and cognitive errors, respectively). The mean decrement for all residents in the postcall condition was 13.1%.

Conclusions

Postcall fatigue is associated with a marginal decrease in proficiency during simulated surgery in neurosurgery residents. In a similar study, general surgery residents showed a statistically significant decrement of 27.3% in the postcall condition. The impact of fatigue on different specialties should be further investigated prior to implementation of a national physician work-hour policy.

Magnetization spoiling in radial FLASH contrast-enhanced MR digital subtraction angiography

PURPOSE

To increase the in-plane spatial resolution and image update rates of 2D magnetic resonance (MR) digital subtraction angiography (DSA) pulse sequences to 0.57 × 0.57 mm and 6 frames/sec, respectively, for intracranial vascular disease applications by developing a radial FLASH protocol and to characterize a new artifact, not previously described in the literature, which arises in the presence of such pulse sequences.

MATERIALS AND METHODS

The pulse sequence was optimized and artifacts were characterized using simulation and phantom studies. With Institutional Review Board (IRB) approval, the pulse sequence was used to acquire time-resolved images from healthy human volunteers and patients with x-ray DSA-confirmed intracranial vascular disease.

RESULTS

Artifacts were shown to derive from inhomogeneous spoiling due to the nature of radial waveforms. Gradient spoiling strategies were proposed to eliminate the observed artifact by balancing gradient moments across TR intervals. The resulting radial 2D MR DSA sequence (2.6 sec temporal footprint, 6 frames/sec with sliding window factor 16, 0.57 × 0.57 mm in-plane) demonstrated small vessel detail and corroborated x-ray DSA findings in intracranial vascular imaging studies.

CONCLUSION

Appropriate gradient spoiling in radial 2D MR DSA pulse sequences improves intracranial vascular depiction by eliminating circular banding artifacts. The proposed pulse sequence may provide a useful addition to clinically applied 2D MR DSA scans.

Combined surgical and endovascular access of the superficial middle cerebral vein to occlude a high-grade cavernous dural arteriovenous fistula: case report

BACKGROUND AND IMPORTANCE

High-grade cavernous sinus (CS) dural arteriovenous fistulae with cortical venous drainage often have a malignant presentation requiring urgent treatment. In the absence of a venous access to the lesion, transarterial embolization can potentially cure these lesions; however, the high concentration of eloquent arterial territories adjacent to the fistula creates a precarious risk of arterial-arterial reflux. In such cases, a combined surgical and endovascular approach may provide the least invasive option.

CLINICAL PRESENTATION

We describe a patient presenting with a venous hemorrhagic infarct caused by a high-grade CS dural arteriovenous fistula (Barrow type D caroticocavernous fistula) with isolated drainage via the superficial middle cerebral vein into engorged perisylvian cortical veins. No transfemoral or ophthalmic strategy was angiographically apparent, and the posterior location of the involved CS compartment mitigated a direct puncture. The patient underwent direct puncture of the superficial middle cerebral vein via an orbitozygomatic craniotomy and the CS was catheterized under fluoroscopic guidance. The CS was coil-embolized back into the distal superficial middle cerebral vein with complete obliteration of the fistula. The patient did well with no new deficits and made an uneventful recovery.

CONCLUSION

This novel combined open surgical and endovascular approach enables obliteration of a CS dural arteriovenous fistula with isolated cortical venous drainage and avoids the additional manipulation with direct dissection and puncture of the CS itself.