Category: Vascular

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Removal of an ICH through an eyebrow incision

J Neurosurg 117:767–773, 2012

Surgical evacuation of spontaneous intracerebral hemorrhage (sICH) remains a subject of controversy. Minimally invasive techniques for hematoma evacuation have shown a trend toward improved outcomes. The aim of the present study is to describe a minimally invasive alternative for the evacuation of sICH and evaluate its feasibility.
Methods
The authors reviewed records of all patients who underwent endoscopic evacuation of an sICH at the UCLA Medical Center between March 2002 and March 2011. All patients in whom the described technique was used for evacuation of an sICH were included in this series. In this approach an incision is made at the superior margin of the eyebrow, and a bur hole is made in the supraorbital bone lateral to the frontal sinus. Using stereotactic guidance, the surgeon advanced the endoscopic sheath along the long axis of the hematoma and fixed it in place at two specific depths where suction was then applied until 75%–85% of the preoperatively determined hematoma volume was removed. An endoscope’s camera, then introduced through the sheath, was used to assist in hemostasis. Preoperative and postoperative hematoma volumes and reduction in midline shift were calculated and recorded. Admission Glasgow Coma Scale and modified Rankin Scale (mRS) scores were compared with postoperative scores.
Results
Six patients underwent evacuation of an sICH using the eyebrow/bur hole technique. The mean preoperative hematoma volume was 68.9 ml (range 30.2–153.9 ml), whereas the mean postoperative residual hematoma volume was 11.9 ml (range 5.1–24.1 ml) (p = 0.02). The mean percentage of hematoma evacuated was 79.2% (range 49%–92.7%). The mean reduction in midline shift was 57.8% (p < 0.01). The Glasgow Coma Scale score improved in each patient between admission and discharge examination. In 5 of the 6 patients the mRS score improved from admission exam to last follow-up. None of the patients experienced rebleeding.
Conclusions
This minimally invasive technique is a feasible alternative to other means of evacuating sICHs. It is intended for anterior basal ganglia hematomas, which usually have an elongated, ovoid shape. The approach allows for an optimal trajectory to the long axis of the hematoma, making it possible to evacuate the vast majority of the clot with only one pass of the endoscopic sheath, theoretically minimizing the amount of damage to normal brain.

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Near-infrared indocyanine green videoangiography (ICGVA) and intraoperative computed tomography (iCT): are they complementary or competitive imaging techniques in aneurysm surgery?

Acta Neurochir (2012) 154:1861–1868

In this pilot study we compared advantages and drawbacks of near-infrared indocyanine green videoangiography (ICGVA) and intraoperative computed tomography (iCT) to investigate if these are complementary or competitive methods to acquire immediate information about blood vessels and potential critical impairment of brain perfusion during vascular neurosurgery.
Methods
A small subset of patients (n = 10) were prospectively enrolled in this feasibility study and received ICGVA immediately after placement of the aneurysm clips. An intraoperative cranial CT angiography (iCTA) was followed by dynamic perfusion CT scan (iCTP) using a 40-slice, sliding-gantry, CT scanner. The vascular patency of major (aneurysm bearing) arteries, visualisation of arising perforating arteries and brain perfusion after clip application were analysed with both techniques.
Results
The ICGVA was able to visualise blood flow and vascular patency of all major vessels and perforating arteries within the visual field of the microscope, but failed to display vessels located within deeper areas of the surgical field. Even small coverage with brain parenchyma impaired detection of vessels. With iCTA high image quality could be obtained in 7/10 cases of clipped aneurysms. Intraoperative CTA was not sufficiently evaluable in one PICA aneurysm and one case of a previously coiled recurrent aneurysm, due to extensive coil artefacts. Small, perforating arteries could not be detected with iCTA. Intraoperative CTP allowed the assessment of global blood flow and brain perfusion in sufficient quality in 5/10 cases, and enabled adequate intraoperative decision making.
Conclusion
A combination of ICGVA and iCT is feasible, with very good diagnostic imaging quality associated with short acquisition time and little interference with the surgical workflow. Both techniques are complementary rather than competing analysing tools and help to assess information about local (ICGVA/iCTA) as well as regional (iCTA/iCTP) blood flow and cerebral perfusion immediately after clipping of intracranial aneurysms.

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A Simple and Quantitative Method to Predict Symptomatic Vasospasm After Subarachnoid Hemorrhage Based on Computed Tomography: Beyond the Fisher Scale

Neurosurgery 71:869–876, 2012

Although the Fisher scale is commonly used to grade vasospasm risk in aneurysmal subarachnoid hemorrhage (aSAH) patients, it fails to account for increasing subarachnoid hemorrhage (SAH) thickness.

OBJECTIVE: We developed a simple quantitative scale based on maximal SAH thickness and compared its reproducibility and ability to predict symptomatic vasospasm against the Fisher scale.

METHODS: The incidence of radiographic and symptomatic vasospasm among 250 aSAH patients treated at our institution was investigated. Admission head computed tomography scans were graded according to the Fisher scale and the proposed scale, which assigns a score from 1 to 5 based on a single measurement of maximum SAH thickness. We calculated vasospasm risk per grade for the Fisher scale and the proposed scale, and compared inter- and intraobserver variability for both scales.

RESULTS: Forty-five patients (20.6%) developed symptomatic vasospasm. On the proposed scale, grade 5 patients were at highest risk, with an odds ratio for symptomatic vasospasm of 11 (95% confidence interval [CI] 2.27-53.37). Odds ratios for proposed grades 4 and 3 were 4.63 (95% CI 1.10-19.59) and 3.04 (95% CI 0.85-10.90), respectively. The odds ratio for Fisher grade 3 was 3.3 (0.96-11.30). Mean inter- and intraobserver agreement was greater for the proposed scale in comparison with the Fisher scale (k0.65 and k0.81 vs k0.51 and k0.35, respectively).

CONCLUSION: The new scale accounted for increasing SAH thickness and was superior to the Fisher scale in inter- and intraobserver agreement and in predicting symptomatic vasospasm, particularly among the highest-risk patients.

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Microsurgical clipping of true posterior communicating artery aneurysms

Acta Neurochir (2012) 154:1707–1710

“True” posterior communicating artery (PCOM) aneurysms are rare variants in which the aneurysm arises solely from the PCOM rather than the junction of the internal carotid artery and the PCOM.

Methods It is critical to note that for true PCOM aneurysms, the neck arises distal to the origin of the PCOM and therefore lies in what is traditionally an intra-operative blind spot. The PCOM must be followed posteriorly to visualise the aneurysm neck for microsurgical clipping.

Conclusions A thorough pre-operative understanding of this unique anatomy is essential in minimising morbidity associated with microsurgical clipping of this aneurysm configuration.

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Independent predictors for recurrence of chronic subdural hematoma

Acta Neurochir (2012) 154:1541–1548 DOI 10.1007/s00701-012-1399-9

Chronic subdural hematoma is characterized by blood in the subdural space that evokes an inflammatory reaction. Numerous factors potentially associated with recurrence of chronic subdural hematoma have been reported, but these factors have not been sufficiently investigated. In this study, we evaluated the independent risk factors of recurrence.

Methods We analyzed data for 420 patients with chronic subdural hematoma treated by the standard surgical procedure for hematoma evacuation at our institution.

Results Ninety-two (21.9 %) patients experienced at least one recurrence of chronic subdural hematoma during the study period. We did not identify any significant differences between chronic subdural hematoma recurrence and current antiplatelet therapy. The recurrence rate was 7 % for the homogeneous type, 21 % for the laminar type, 38 % for the separated type, and 0 % for the trabecular type. The rate of recurrence was significantly lower in the homogeneous and trabecular type than in the laminar and separated type. We performed a multivariate logistic regression analysis and found that postoperative midline shifting (OR, 3.6; 95 % CI, 1.618-7.885; p00.001), diabetes mellitus (OR, 2.2; 95 % CI, 1.196-3.856; p=0.010), history of seizure (OR, 2.6; 95 % CI, 1.210-5.430; p=0.014), width of hematoma (OR, 2.1; 95 % CI, 1.287-3.538; p=0.003), and anticoagulant therapy (OR, 2.7; 95 % CI, 1.424-6.960; p=0.005) were independent risk factors for the recurrence of chronic subdural hematoma.

Conclusions We have shown that postoperative midline shifting (≥5 mm), diabetes mellitus, preoperative seizure, preoperative width of hematoma (≥20 mm), and anticoagulant therapy were independent predictors of the recurrence of chronic subdural hematoma. According to internal architecture of hematoma, the rate of recurrence was significantly lower in the homogeneous and the trabecular type than the laminar and separated type.

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Long-term Outcomes After Staged-Volume Stereotactic Radiosurgery for Large Arteriovenous Malformations

Neurosurgery 71:632–644, 2012 DOI: 10.1227/NEU.0b013e31825fd247

Stereotactic radiosurgery is an effective treatment modality for small arteriovenous malformations (AVMs) of the brain. For larger AVMs, the treatment dose is often lowered to reduce potential complications, but this decreases the likelihood of cure. One strategy is to divide large AVMs into smaller anatomic volumes and treat each volume separately.

OBJECTIVE: To prospectively assess the long-term efficacy and complications associated with staged-volume radiosurgical treatment of large, symptomatic AVMs.

METHODS: Eighteen patients with AVMs larger than 15 mL underwent prospective staged-volume radiosurgery over a 13-year period. The median AVM volume was 22.9 mL (range, 15.7-50 mL). Separate anatomic volumes were irradiated at 3- to 9-month intervals (median volume, 10.9 mL; range, 5.3-13.4 mL; median marginal dose, 15 Gy; range, 15-17 Gy). The AVM was divided into 2 volumes in 10 patients, 3 volumes in 5 patients, and 4 volumes in 3 patients. Seven patients underwent retreatment for residual disease.

RESULTS: Actuarial rates of complete angiographic occlusion were 29% and 89% at 5 and 10 years. Five patients (27.8%) had a hemorrhage after radiosurgery. Kaplan-Meier analysis of cumulative hemorrhage rates after treatment were 12%, 18%, 31%, and 31% at 2, 3, 5, and 10 years, respectively. One patient died after a hemorrhage (5.6%).

CONCLUSION: Staged-volume radiosurgery for AVMs larger than 15 mL is a viable treatment strategy. The long-term occlusion rate is high, whereas the radiation-related complication rate is low. Hemorrhage during the lag period remains the greatest source of morbidity and mortality.

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The Contralateral Transcingulate Approach

Neurosurgery 71[ONS Suppl 1]:ons4–ons14, 2012

The contralateral transcingulate approach is a variation of the contralateral transcallosal approach for lesions located in the cingulate gyrus and deep white matter of the medial frontal lobe.

OBJECTIVE: To more thoroughly describe the contralateral transcingulate approach by reporting our operative technique and results.

METHODS: This approach positions the head with the midline horizontally, lesion on the upside, allowing gravity retraction of the dependent frontal lobe. Bifrontal craniotomy and splitting of the interhemispheric fissure create a crossing trajectory from the contralateral fissure to the ipsilateral cingulate gyrus that maximizes lateral exposure.

RESULTS: Eleven patients with vascular lesions were treated with the contralateral transcingulate approach (9 patients with cavernous malformations and 2 patients with arteriovenous malformations). Eight lesions were located on the left side, 5 in the cingulate gyrus, and 6 in the deep frontal lobe. The falx was cut in 5 patients to extend the crossing trajectory. All lesions were removed completely, with neurological morbidity in 1 patient caused by venous infarction.

CONCLUSION: Although similar to the contralateral transcallosal approach, the contralateral transcingulate approach accesses lesions outside the ventricle and has a steeper crossing trajectory. This approach requires no disruption of brain tissue with lesions on the cingulate surface and only a small incision in cingulate gyrus with lesions in the deep frontal lobe. The ipsilateral pericallosal and callosomarginal arteries provide dependable landmarks for transcingulate dissection. The contralateral transcingulate approach offers an alternative medial approach to lesions near language and motor areas and avoids lateral transcortical approaches, awake speech mapping, and risk to eloquent cortex in the dominant hemisphere.

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Natural history of DAVFs without cortical venous drainage

J Neurosurg 117:539–545, 2012

The goal of this study was to determine the clinical course of Borden-Shucart Type I cranial dural arteriovenous fistulas (DAVFs) and to calculate the annual rate of conversion of these lesions to more aggressive fistulas that have cortical venous drainage (CVD).

Methods. A retrospective chart review was conducted of all patients harboring DAVFs who were seen at the authors’ institution between 1997 and 2009. Twenty-three patients with Type I DAVFs who had available clinical follow-up were identified. Angiographic and clinical data from these patients were reviewed. Neurological outcome and status of presenting symptoms were assessed during long-term follow-up.

Results. Of the 23 patients, 13 underwent endovascular treatment for intolerable tinnitus or ophthalmological symptoms, and 10 did not undergo treatment. Three untreated patients died of unrelated causes. In those who were treated, complete DAVF obliteration was achieved in 4 patients, and palliative reduction in DAVF flow was achieved in 9 patients. Of the 19 patients without radiographic cure, no patient developed intracranial hemorrhage or nonhemorrhagic neurological deficits (NHNDs), and no patient died of DAVF-related causes over a mean follow-up of 5.6 years. One patient experienced a spontaneous, asymptomatic obliteration of a partially treated DAVF in late follow-up, and 2 patients experienced a symptomatic conversion of their DAVF to a higher-grade fistula with CVD in late follow-up. The annual rate of conversion to a higher-grade DAVF based on Kaplan-Meier cumulative event-free survival analysis was 1.0%. The annual rate of intracranial hemorrhage, NHND, and DAVF-related death was 0.0%.

Conclusions. A small number of Type I DAVFs will convert to more aggressive DAVFs with CVD over time. This conversion to a higher-grade DAVF is typically heralded by a change in patient symptoms. Follow-up vascular imaging is important, particularly in the setting of recurrent or new symptoms.

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A randomized study of urgent computed tomography–based hematoma puncture and aspiration in the emergency department and subsequent evacuation using craniectomy versus craniectomy only

J Neurosurg 117:566–573, 2012

When treating patients with a spontaneous supratentorial massive (≥ 70 ml) intracerebral hemorrhage (ICH), the results of surgery are gloomy. A worsening pupil response has been observed in patients preoperatively, despite blood pressure control and diuretic administration. Because open surgery needs time for decompression to occur, the authors conducted a prospective randomized study to determine whether patients who have suffered a massive ICH can benefit from a more urgently performed decompressive procedure.

Methods. Overall, 36 eligible patients admitted 6 or fewer hours post-ictus were enrolled in the study. In Group A, 12 patients underwent CT-based hematoma puncture and partial aspiration in the emergency department (ED) and subsequent evacuation via a craniectomy; in Group B, 24 patients underwent hematoma evacuation via a craniectomy only. Pupil responses were categorized into 5 grades (Grade 0, bilaterally fixed; Grade 1, unilaterally fixed with the fixed pupil > 7 mm; Grade 2, unilaterally fixed with the fixed pupil ≤ 7 mm; Grade 3, a unilaterally sluggish response; and Grade 4, a bilaterally brisk response). Grades were obtained on admission, at surgical decompression (defined as the point at which liquid hematoma began to flow out in Group A and at dural opening in Group B), and at completion of craniectomy. The Barthel Scale was used to assess survivors’ functional outcome at 12 months. Comparisons were made between Groups A and B. Logistic regression analysis was used to evaluate the positive likelihood ratio of all variables for survival and function (Barthel Scale score of ≥ 35 at 12 months).

Results. Decompressive surgery was undertaken approximately 60 minutes earlier in Group A than B. A worsening pupil reflex before decompression was observed in no Group A patient and in 9 Group B patients. At the time of decompression pupil response was better in Group A than B (p < 0.05). Although only approximately one-third of the hematoma volume documented on initial CT scanning had been drained before the craniectomy in Group A, when partial aspiration was followed by craniectomy, better pupil-response results were obtained in Group A at the completion of craniectomy, and survival rate and 12-month Barthel Scale score were better as well (p < 0.05). Logistic regression analysis revealed that one variable, a minimum pupil grade of 3 at the time of decompression, had the highest predictive value for survival at 12 months (8.0, 95% CI 2.0–32.0), and a pupil grade of 4 at the same time was the most valuable predictor of a Barthel Scale score of 35 or greater at 12 months (15.0, 95% CI 1.9–120.9).

Conclusions. Patients with massive spontaneous supratentorial ICHs may benefit from more urgent surgical decompression. The results of logistic regression analysis implied that, to improve long-term functional outcome, decompression should be performed in patients before herniation occurs. Due to the fact that most of these patients have signs of herniation when presenting to the ED and because conventional surgical decompression requires time to take effect, this combination of surgical treatment provides a feasible and effective surgical option.

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Surgical Management of Giant Posterior Communicating Artery Aneurysms

Neurosurgery 71[ONS Suppl 1]:ons43–ons51, 2012

Giant posterior communicating artery (PCoA) aneurysms (> 25 mm) are rare lesions associated with a poor prognosis and high rates of morbidity and mortality.

OBJECTIVE: To review the clinical results of giant PCoA aneurysms surgically treated at our institution, focusing on operative nuances.

METHODS: All cases of giant PCoA aneurysms treated surgically at our institution were identified from a prospectively maintained patient database. Patient demographic factors, medical comorbidities, rupture status, neurological presentation, clinical outcomes, and surgical records were critically reviewed.

RESULTS: From 1989 to 2010, 11 patients (10 women) underwent surgical clipping of giant PCoA aneurysms. Presenting signs and symptoms included cranial nerve palsies, diminished mental status, headache, visual changes, and seizures. Five aneurysms were ruptured on admission. All aneurysms were clipped primarily except 1, which was treated by parent artery sacrifice and extracranial-to-intracranial bypass after intraoperative aneurysm rupture. Perioperative morbidity and mortality rates were 36% (4 of 11) and 18.3% (2 of 11), respectively. Excellent or good clinical outcomes, defined as modified Rankin Scale scores ≤ 2, were achieved in 86% (5 of 6) of patients available for long-term clinical follow-up (mean, 12.5 ± 13.6 months).

CONCLUSION: Giant PCoA aneurysms are rare vascular lesions that may present with a variety of neurological signs and symptoms. These lesions can be successfully managed surgically with satisfactory morbidity and mortality rates. To the best of our knowledge, this is the largest surgical series of giant PCoA aneurysms published to date.

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The use of intraoperative near-infrared indocyanine green videoangiography in the microscopic resection of hemangioblastomas

Acta Neurochir (2012) 154:1407–1412 

The authors assessed the usefulness of intraoperative near-infrared indocyanine green videoangiography (ICG-VA) in the microscopic resection of hemangioblastomas.

Methods From January 2009 to February 2012, nine consecutive patients (seven men, two women) who underwent surgery for hemangioblastomas using intraoperative ICGVA were included in this study. Surgery was performed on four cystic cerebellar lesions with mural nodules, two solid tumors (one in the cerebellar hemisphere and one in the medulla oblongata), one spinal tumor and multiple tumors in two patients with von Hippel-Lindau disease. Of the nine patients, three were treated for recurrent tumor. The ICGinduced fluorescence images of hemangioblastomas with variable presentation were evaluated.

Results All tumors could be completely removed en bloc. Blood flow in the tumor and tumor-related vessels at the brain surface were clearly detected by ICG-VA in all cases, except one recurrent tumor where postoperative adhesive scar tissue obstructed ICG-induced fluorescence resulting in poor delineation of the blood flow patterns and tumor margins. ICG-VAwas also helpful for detecting the multiple small mural nodules within the cyst or the tumors buried under thin gliotic neural tissue despite reduced fluorescence.

Conclusion Intraoperative ICG-VA is a safe and easy modality for confirming the vascular flow patterns in hemangioblastomas. In addition, ICG-VA provided useful information for intracystic small lesions or lesions concealed under thin brain tissue in order to accomplish total resection of these tumors.

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Hemorrhage From Arteriovenous Malformations During Pregnancy

Neurosurgery 71:349–356, 2012 DOI: 10.1227/NEU.0b013e318256c34b

Previous hemorrhage, deep venous drainage, and deep location are established risk factors for arteriovenous malformation (AVM) hemorrhage. Although pregnancy is an assumed risk factor, there is a relative paucity of data to support this neurosurgical tenet.

OBJECTIVE: To elucidate the hemorrhage rate of AVMs during pregnancy.

METHODS: We reviewed the records of 54 women with an angiographic diagnosis of an AVM at our institution. Annual hemorrhage rates were calculated as the ratio of the number of bleeds to total number of patient-years of follow-up. Patient-years of followup were tallied assuming lesion presence from birth until AVM obliteration. The Cox proportional hazards model for hemorrhage with pregnancy as the time-dependent variable was used to calculate the hazard ratio.

RESULTS: Five hemorrhages in 4 patients occurred over 62 pregnancies, yielding a hemorrhage rate of 8.1% per pregnancy or 10.8% per year. Over the remaining 2461.3 patient-years of follow-up, only 28 hemorrhages occurred, yielding an annual hemorrhage rate of 1.1%. The hazard ratio for hemorrhage during pregnancy was 7.91 (P = 2.23 x 10-4), increasing to 18.12 (P = 7.31 x 10-5) when limiting the analysis to patient follow-up up to age 40.

CONCLUSION: Because of the increased risk of hemorrhage from AVMs during pregnancy, we recommend intervention in women who desire to bear children, particularly if the AVM has bled. If the AVM is discovered during pregnancy, we recommend early intervention if it has ruptured; if it is unruptured, we recommend comprehensive counseling, weighing risks of intervention against continuation of pregnancy without intervention.

 

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Stereotactic radiosurgery after embolization for AVMs

J Neurosurg 117:265–275, 2012

In this paper the authors’ goal was to define the long-term benefits and risks of stereotactic radiosurgery (SRS) for patients with arteriovenous malformations (AVMs) who underwent prior embolization.

Methods. Between 1987 and 2006, the authors performed Gamma Knife surgery in 996 patients with brain AVMs; 120 patients underwent embolization followed by SRS. In this series, 64 patients (53%) had at least one prior hemorrhage. The median number of embolizations varied from 1 to 5. The median target volume was 6.6 cm3 (range 0.2–26.3 cm3). The median margin dose was 18 Gy (range 13.5–25 Gy).

Results. After embolization, 25 patients (21%) developed symptomatic neurological deficits. The overall rates of total obliteration documented by either angiography or MRI were 35%, 53%, 55%, and 59% at 3, 4, 5, and 10 years, respectively. Factors associated with a higher rate of AVM obliteration were smaller target volume, smaller maximum diameter, higher margin dose, timing of embolization during the most recent 10-year period (1997–2006), and lower Pollock-Flickinger score. Nine patients (8%) had a hemorrhage during the latency period, and 7 patients died of hemorrhage. The actuarial rates of AVM hemorrhage after SRS were 0.8%, 3.5%, 5.4%, 7.7%, and 7.7% at 1, 2, 3, 5, and 10 years, respectively. The overall annual hemorrhage rate was 2.7%. Factors associated with a higher risk of hemorrhage after SRS were a larger target volume and a larger number of prior hemorrhages. Permanent neurological deficits due to adverse radiation effects (AREs) developed in 3 patients (2.5%) after SRS, and 1 patient had delayed cyst formation 210 months after SRS. No patient died of AREs. A larger 12-Gy volume was associated with higher risk of symptomatic AREs. Using a case-control matched approach, the authors found that patients who underwent embolization prior to SRS had a lower rate of total obliteration (p = 0.028) than patients who had not undergone embolization.

Conclusions. In this 20-year experience, the authors found that prior embolization reduced the rate of total obliteration after SRS, and that the risks of hemorrhage during the latency period were not affected by prior embolization. For patients who underwent embolization to volumes smaller than 8 cm3, success was significantly improved. A margin dose of 18 Gy or more also improved success. In the future, the role of embolization after SRS should be explored.

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Long-term visual outcome after microsurgical removal of occipital lobe cavernomas

J Neurosurg 117:295–301, 2012

Cavernomas in the occipital lobe are relatively rare. Because of the proximity to the visual cortex and incoming subcortical tracts, microsurgical removal of occipital cavernomas may be associated with a risk of visual field defects. The goal of the study was to analyze long-term outcome after operative treatment of occipital cavernomas with special emphasis on visual outcome.

Methods. Of the 390 consecutive patients with cavernomas who were treated at Helsinki University Central Hospital between 1980 and 2011, 19 (5%) had occipital cavernomas. Sixteen patients (4%) were surgically treated and are included in this study. The median age was 39 years (range 3–59 years). Seven patients (56%) suffered from hemorrhage preoperatively, 5 (31%) presented with visual field deficits, 11 (69%) suffered from seizures, and 4 (25%) had multiple cavernomas. Surgery was indicated for progressive neurological deterioration. The median follow-up after surgery was 5.25 years (range 0.5–14 years).

Results. All patients underwent thorough neuroophthalmological assessment to determine visual outcome after surgery. Visual fields were classified as normal, mild homonymous visual field loss (not disturbing the patient, driving allowed), moderate homonymous visual field loss (disturbing the patient, driving prohibited), and severe visual field loss (total homonymous hemianopia or total homonymous quadrantanopia). At the last follow-up, 4 patients (25%) had normal visual fields, 6 (38%) had a mild visual field deficit, 1 (6%) complained of moderate visual field impairment, and 5 (31%) had severe homonymous visual field loss. Cavernomas seated deeper than 2 cm from the pial surface carried a 4.4-fold risk of postoperative visual field deficit relative to superficial ones (p = 0.034). Six (55%) of the 11 patients presenting with seizures were seizure-free postoperatively. Eleven (69%) of 16 patients had no disability during the long-term follow-up.

Conclusions. Surgical removal of occipital cavernomas may carry a significant risk of postoperative visual field deficit, and the risk is even higher for deeper lesions. Seizure outcome after removal of these cavernomas appeared to be worse than that after removal in other supratentorial locations. This should be taken into account during preoperative planning.

 

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Yield of CTA in catheter angiography–negative SAH

J Neurosurg 117:309–315, 2012

The yield of CT angiography (CTA) and MR angiography (MRA) in patients with subarachnoid hemorrhage (SAH) who have a negative initial catheter angiogram is currently not well understood. This study aims to determine the yield of CTA and MRA in a prospective cohort of patients with SAH and a negative initial catheter angiogram.

Methods. From January 1, 2005, until September 1, 2010, the authors instituted a prospective protocol in which patients with SAH—as documented by noncontrast CT or CSF xanthochromia and a negative initial catheter angiogram— were evaluated using CTA and MRA to assess for causative cerebral aneurysms. Two neuroradiologists independently evaluated the noncontrast CT scans to determine the SAH pattern (perimesencephalic or not) and the CT and MR angiograms to assess for causative cerebral aneurysms.

Results. Seventy-seven patients were included, with a mean age of 52.8 years (median 54 years, range 19–88 years). Fifty patients were female (64.9%) and 27 male (35.1%). Forty-three patients had nonperimesencephalic SAH (55.8%), 29 patients had perimesencephalic SAH (37.7%), and 5 patients had CSF xanthochromia (6.5%). Computed tomography angiography demonstrated a causative cerebral aneurysm in 4 patients (5.2% yield), all of whom had nonperimesencephalic SAH (9.3% yield). Mean aneurysm size was 2.6 mm (range 2.1–3.3 mm). Magnetic resonance angiography demonstrated only 1 of these aneurysms. No causative cerebral aneurysms were found in patients with perimesencephalic SAH or CSF xanthochromia.

Conclusions. Computed tomography angiography is a valuable adjunct in the evaluation of patients with nonperimesencephalic SAH who have a negative initial catheter angiogram, demonstrating a causative cerebral aneurysm in 9.3% of patients.

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Petrosal approaches to brainstem cavernous malformations

Neurosurg Focus 33 (2):E10, 2012

Although they provide excellent ventral and lateral exposure of the brainstem, petrosal approaches to brainstem cavernous malformations (CMs) are infrequently reported.

Methods. The authors reviewed their experience with petrosal approaches to brainstem CMs in combination with a comprehensive review of the literature to elucidate resection rates, complication rates, and outcomes.

Results. Including their own results, the authors found 65 cases in 20 reports of brainstem CMs treated with petrosal approaches. The specific approaches were posterior petrosal in 37 cases (57%), anterior petrosal in 17 (26%), extended posterior petrosal in 10 (15%), and a combined petrosal approach in 1 case (2%). For 50 cases in 16 reports with detailed outcome information, the overall complete resection rate was 90%, with early postoperative morbidity reported in 30% of cases and permanent morbidity in 14%. The rate of CSF leakage was 6%.

Conclusions. The versatile petrosal approaches to brainstem CMs are associated with good outcomes and an acceptable morbidity rate. More expansive lesions can be approached using a combination of the standard anterior and posterior petrosal approach, preserving hearing and avoiding the greater complication rates associated with extended posterior petrosal approaches.

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Endoscopic indocyanine green video angiography in aneurysm surgery

J Neurosurg 117:302–308, 2012

Recently, intraoperative fluorescence video angiography using indocyanine green (ICG) has been widely used in aneurysm surgery. This is a simple and useful method to confirm complete occlusion of the aneurysm lumen and preservation of blood flow in the arteries around the aneurysm. However, the observation field of ICG video angiography is limited under a microscope, making it difficult to confirm the flow in the arteries behind the parent arteries or aneurysm.

The authors developed a new technique of intraoperative endoscopic ICG video angiography to assess the blood flow in perforating arteries hidden by the parent arteries or aneurysm. The endoscope emits excitation light with a wavelength of approximately 800 nm, and video images were obtained through a cut filter.

The authors used this ICG fluorescence endoscope in treating 3 patients with unruptured cerebral aneurysms. During clip placement, the endoscope was inserted to confirm aneurysm occlusion. Then, ICG was intravenously administered, and the fluorescence in the vessels was observed via the endoscope as well as under the microscope. The blood flow in the perforating arteries was clearly identified, and no procedural complication occurred.

The authors conclude that the technique is very useful and facilitates intraoperative real-time assessment of the patency of perforating arteries behind parent arteries or aneurysms.

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Microsurgical Clipping of Posterior Communicating Artery Aneurysms in the Endovascular Era

Neurosurgery 71:285–295, 2012 DOI: 10.1227/NEU.0b013e318256c3eb

Many neurosurgeons feel competent clipping posterior communicating artery (PCoA) aneurysms and include this lesion in their practice. However, endovascular therapy removes simple aneurysms that would have been easiest to clip with the best results. What remains are aneurysms with complex anatomy and technical challenges that are not well described.

OBJECTIVE: A contemporary surgical series with PCoA aneurysms is reviewed to define the patients, microsurgical techniques, and outcomes in current practice. METHODS: A total of 218 patients had 218 PCoA aneurysms that were treated microsurgically during an 11-year period. Complexities influencing aneurysm management included (1) large/giant size; (2) fetal posterior cerebral artery; (3) previous coiling; (4) anterior clinoidectomy; (5) adherence of the anterior choroidal artery (AChA); (6) intraoperative aneurysm rupture; (7) complex clipping; and (8) atherosclerotic calcification.

RESULTS: Simple PCoA aneurysms were encountered in 113 patients (51.8%) and complex aneurysms in 105 (48.2%). Adherent AChA (13.8%) and intraoperative rupture (11.5%) were the most common complexities. Simple aneurysms had favorable outcomes in 86.6% of patients, whereas aneurysms with 1 or multiple complexities had favorable outcomes in 78.2% and 75.0%, respectively. Intraoperative rupture (P , .01), large/giant size (P = .04), and complex clipping (P = .05) were associated with increased neurological worsening.

CONCLUSION: Because endovascular therapy alters the surgical population, neurosurgeons should recalibrate their expectations with this once straightforward aneurysm. The current mix of PCoA aneurysms requires advanced techniques including clinoidectomy, AChA microdissection, complex clipping, and facility with intraoperative rupture. Microsurgery is recommended for recurrent aneurysms after coiling, complex branches, aneurysms causing oculomotor nerve palsy, multiple aneurysms, and patients with hematomas.

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Long-term Results of Enterprise Stent-Assisted Coiling of Cerebral Aneurysms

Neurosurgery 71:239–244, 2012 DOI: 10.1227/NEU.0b013e3182571953

The Enterprise Vascular Reconstruction Device and Delivery System (Cordis; the Enterprise stent) was approved for use in conjunction with coiling of wide-necked aneurysms in 2007. No published long-term aneurysm occlusion or complication data exist for the Enterprise system.

OBJECTIVE: We compiled data on consecutive patients treated with Enterprise stent-assisted coiling of aneurysms from 9 high-volume neurointerventional centers.

METHODS: A 9 center registry was created to evaluate large volume data on the delayed safety and efficacy of the Enterprise stent system. Pooled data were compiled for consecutive patients undergoing Enterprise stent-assisted coiling at each institution prior to May 2009.

RESULTS: Two-hundred twenty-nine patients with 229 aneurysms, 32 of which were ruptured aneurysms, were included in the study. Mean clinical and angiographic follow-up was 619.6 ± 26.4 days and 655.7 ± 25.2 days, respectively. Mean aneurysm size was 9.2 ± 0.4 mm. Fifty-nine percent of patients demonstrated 100% coil obliteration and 81% had 90% or higher occlusion at last follow-up angiography. A total of 19 patients (8.3%) underwent retreatment of their aneurysms during the follow-up period. Angiographic in-stent stenosis was seen in 3.4% and thromboembolic events occurred in 4.4%. Overall, 90% of patients who underwent Enterprise-assisted coiling had a modified Rankin Scale score of 2 or less at last follow-up. A poor modified Rankin Scale score was strongly associated with rupture status (P < .001).

CONCLUSION: Although this study is limited by its retrospective nature, the Enterprise stent system appears to be an effective, safe, and durable treatment for intracranial aneurysms when used in conjunction with coiling.

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Early recurrent hemorrhage after coil embolization in ruptured intracranial aneurysms

Neuroradiology (2012) 54:719–726 DOI 10.1007/s00234-011-0950-3

The authors present a series of patients in whom early rebleeding occurred after coiling for ruptured aneurysms. We investigated the incidence and possible mechanisms of early rebleeding.

Methods This study consisted of 1,167 consecutive patients who underwent coiling for a ruptured saccular aneurysm. Clinical and radiological data were collected retrospectively from three institutions. Early rebleeding was defined as occurrence of further bleeding within 30 days after coiling with worsening of the patient’s condition. We divided early rebleeding into hyperacute, subacute, and delay groups depending on the timing of rebleeding after coil embolization.

Results Incidence of early rebleeding after coiling of a ruptured saccular aneurysm was 1.1% (13 of 1,167), and mortality was 31% (4 of 13) in our series. Out of ten patients in hyperacute group, three (30%) had incomplete occlusion result and six patients (60%) underwent intraarterial (IA) infusion of abciximab or tirofiban during the procedures. Seven patients (70%) had an intracerebral hemorrhage (ICH) on initial computed tomography. Four patients died, another four sustained severe disabilities, and the others had good recovery. All three patients in subacute and delay group showed recanalization on post-rebleeding angiography and made an excellent recovery.

Conclusion Early rebleeding was associated with high mortality and morbidity. IA abciximab infusion or thrombolytic interventions during the procedure, maintenance of anticoagulation after the procedure, incomplete treatment of the aneurysms, and presence of ICH seemed to be related to hyperacute early rebleeding after coiling. Increased aneurysmal size and coil compaction could induce subacute and delayed early rebleeding.

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