Tag: Microsurgery

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Recovery from oculomotor nerve palsy due to posterior communicating artery aneurysms: results after clipping versus coiling in a single-center series

Recovery from oculomotor nerve palsy due to posterior communicating artery aneurysms- results after clipping versus coiling in a single-center series

Acta Neurochir (2014) 156:879–884

Oculomotor nerve palsy (ONP) is a common clinical manifestation of ruptured or unruptured posterior communicating artery (PcomA) aneurysms. Although microsurgical clip ligation has been proven a safe and durable treatment, endovascular management is emerging as an increasingly popular alternative. The aim of our study is to compare the recovery rate from ONP and assess the safety and long-term durability of both techniques.

Methods We have reviewed the retrospective data concerning twenty-two patients treated at our institution between 2004 and 2012 for PcomA aneurysms with ONP. Seven patients were operated on via a standard pterional approach, and fourteen were treated by endovascular occlusion with coils. One patient was managed conservatively. Pre-treatment and post-treatment severity of ONP was recorded, as well as the duration of symptoms before admission and treatment-related complications.

Results All seven patients who underwent surgery improved, with six total recoveries and one partial recovery. Among the fourteen patients treated by embolization, thirteen initially recovered, but long-term follow-up revealed three cases of exacerbation of ONP after refilling of the aneurysms. Two of them were clipped, and one embolized. Also, one partially resolved patient underwent a second embolization. No severe complications occurred in either group.

Conclusions Despite the small number of patients, our study suggests that both surgical clipping and embolization are safe and effective methods in regards to functional recovery (complete ONP recovery in about 85 % of the cases). However, coiling may lead to delayed recurrence of third cranial nerve (CN) palsy at long-term follow-up, requiring additional treatment. Keywords

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Predictive value of intraoperative 5-aminolevulinic acid–induced fluorescence for detecting bone invasion in meningioma surgery

Predictive value of intraoperative 5-aminolevulinic

J Neurosurg 120:840–845, 2014

Bone invasion is a major concern in meningioma surgery, since it is predictive of the recurrence of cranial involvement, morbidity, and mortality. Bone invasion has been reported in 20%–68% of studies with histopathologically confirmed data. Unfortunately, radical resection of bone invasion remains challenging. The aim of this study was to assess the role of 5-aminolevulinic acid (5-ALA) fluorescence in guiding the resection of bone-invading meningiomas. To this purpose, the sensitivity, specificity, and positive and negative predictive values of 5-ALA in detecting meningioma bone invasion were evaluated.

Methods. Data from 12 patients affected by bone-invading meningiomas (7 with skull base and 5 with convexity meningiomas) who had undergone surgery with the assistance of 5-ALA fluorescence and neuronavigation between July 2012 and March 2013 at the Department of Neurosurgery of Padua were retrospectively analyzed. To evaluate the sensitivity and specificity of 5-ALA fluorescence in detecting meningioma tissue, a pathologist analyzed 98 surgical bone samples under blue light, according to different fluorescence patterns. Magnetic resonance images and CT scans were obtained pre- and postoperatively to determine the extent of bone invasion resection.

Results. The rate of 5-ALA–induced fluorescence of both tumor and bone invasion was 100%. Based on the pathological examination of bone specimens, 5-ALA presented a sensitivity of 89.06% (95% CI 81.41%–96.71%) and a specificity of 100% in detecting meningioma bone invasion, while the positive and negative predictive values were 100% and 82.93% (95% CI 71.41%–94.45%), respectively. At the postoperative stage, MRI did not detect cases of meningioma bone invasion, whereas CT scans revealed residual hyperostosis in 2 cases.

Conclusions. In summary, 5-ALA fluorescence represents a suitable and reliable technique for identifying and removing bone infiltration by meningiomas. However, further studies are needed to prove the clinical consequences of this promising technique in a larger population.

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Flexible Omnidirectional Carbon Dioxide Laser as an Effective Tool for Resection of Brainstem, Supratentorial, and Intramedullary Cavernous Malformations

Ponto-mesencephalic cavernoma

Operative Neurosurgery 10:34–45, 2014

Lasers have a long history in neurosurgery, yet bulky designs and difficult ergonomics limit their use. With its ease of manipulation and multiple applications, the OmniGuide CO2 laser has reintroduced laser technology to the microsurgical resection of brain and spine lesions. This laser, delivered through a hollow-core fiber lined with a unidirectional mirror, minimizes energy loss and allows precise targeting.

OBJECTIVE: To analyze resections performed by the senior author from April 2009 to March 2013 of 58 cavernous malformations (CMs) in the brain and spine with the use of the OmniGuide CO2 laser, to reflect on lessons learned from laser use in eloquent areas, and to share data on comparisons of laser power calibration and histopathology.

METHODS: Data were collected from electronic medical records, radiology reports, operative room records, OmniGuide CO2 laser case logs, and pathology records.

RESULTS: Of 58 CMs, approximately 50% were in the brainstem (30) and the rest were in supratentorial (26) and intramedullary spinal locations (2). Fifty-seven, ranging from 5 to 45 mm, were resected, with a subtotal resection in 1. Laser power ranged from 2 to 10 W. Pathology specimens showed minimal thermal damage compared with traditionally resected specimens with bipolar coagulation.

CONCLUSION: The OmniGuide CO2 laser is safe and has excellent precision for the resection of supratentorial, brainstem, and spinal intramedullary CMs. No laser-associated complications occurred, and very low energy was used to dissect malformations from their surrounding hemosiderin-stained parenchymas. The authors recommend its use for deep-seated and critically located CMs, along with traditional tools.

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Surgical complications after transsphenoidal microscopic and endoscopic surgery for pituitary adenoma: a consecutive series of 506 procedures

Treatment of acromegaly by endoscopic transsphenoidal surgery

Acta Neurochir (2014) 156:441–449

This single-institution, consecutive series of transsphenoidal procedures included all patients in a defined population of 2.6 million inhabitants who underwent surgery during a specific time period.

Objective We sought to determine the surgical complication rate and overall survival rate after transsphenoidal surgery for pituitary adenoma.

Methods All transsphenoidal procedures for histologically verified pituitary adenomas performed between September 2002 and February 2011 at our institution were included in this study. The data were obtained from a prospectively collected database and from reviewing medical records. No patients were lost to follow-up, and the median follow-up time was 28 months.

Results A total of 506 transsphenoidal procedures were performed on 446 patients. There were 268 microscopic and 238 endoscopic procedures involving 352 non-functioning and 154 hormone-secreting adenomas. A total of 73 % of the procedures were primary surgeries, and 27 % were repeat surgeries for tumor recurrence. The overall complication rate was 9.1 %. The three most frequent complications were cerebrospinal fluid (CSF) leakage (4.7 %), meningitis (2 %), and visual deterioration (2 %). Multivariate analyses showed that the overall risk for complications increased with older age, surgery for recurrent tumors, and surgery performed by a low-volume surgeon. There was no significant difference in the overall complication rate between the microsurgical and endoscopic techniques. The rate of surgical mortality was 0.6 %, and the overall survival rates at 1 and 5 years were 95 % and 90 %, respectively. The only negative predictor of survival was older age.

Conclusions Transsphenoidal surgery for pituitary adenomas has a low complication rate and a low rate of mortality. We did not find a significant difference in the complication rate between endoscopic and microscopic techniques.

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Microsurgical resection of extensive craniopharyngiomas using a frontolateral approach

Microsurgical resection of extensive craniopharyngiomas using a frontolateral approach

J Neurosurg 120:559–570, 2014

An extensive craniopharyngioma is a tumor that extends into multiple compartments (subarachnoid spaces) and attains a size larger than 4 cm. A wide spectrum of approaches and strategies has been used for resection of such craniopharyngiomas. In this report the authors focused on the feasibility and efficacy of microsurgical resection of extensive craniopharyngiomas using a frontolateral approach.

Methods. A retrospective analysis was performed on 16 patients with extensive craniopharyngiomas who underwent operations using a frontolateral approach at one institution. The preoperative and postoperative clinical and radiological data, as well as the operative videos, were reviewed. The main focus of the review was the extent of radical tumor removal, early postoperative outcome, and approach-related complications.

Results. Gross-total resection of craniopharyngioma was achieved in 14 (87.5%) of 16 cases. Early after surgery (within 3 months), 1 patient showed improvement in hormonal status, while in the remaining 15 patients it worsened. No major neurological morbidity was observed. Two patients experienced temporary psychotic disorders. Visual function improved in 6 patients and remained unchanged in 9. One patient experienced a new bitemporal hemianopsia. Three patients with features of short-term memory disturbances at presentation did show improvement after surgery. There were no deaths or significant approach-related morbidity in this patient series. Only 1 patient required revision surgery for a CSF leak.

Conclusions. The safe and simple frontolateral approach provides adequate access even to extensive craniopharyngiomas and enables their complete removal with a reasonable morbidity and approach-related complication rate.

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Focused opening of the sylvian fissure for microsurgical management of MCA aneurysms

Focused opening of the sylvian fissure for microsurgical management of MCA aneurysms

Acta Neurochir (2014) 156:17–25

A wide sylvian opening, with either a proximal or distal start, has been standard for microsurgical management of middle cerebral artery (MCA) aneurysms. However, extensive sylvian dissection is potentially associated with increased incidence of iatrogenic injury to the brain and neurovascular structures. The aim of the present study was to describe the technique of focused opening of the sylvian fissure for microsurgical management of MCA aneurysms with additional tips on handling difficulties which may be encountered with this technique.

Method A 3D image-based anatomic orientation, clipping field–focused surgical planning, slack brain, and high magnification are the basic requirements for this approach. A 10– 15 mm sylvian opening is placed so that it allows safe access and a good surgical view of the MCA aneurysm clipping field. Under proximal control of the MCA, the aneurysm neck can be dissected and clipped effectively and safely, in this small surgical field.

Results The presented technique has been developed and refined by the senior author during the surgery of 1,097 aneurysms over the last 13 years. It has proved to be safe, and effective for clipping of both ruptured and unruptured MCA aneurysms. Its greatest advantages are a shorter operative time and less brain and vessel manipulation compared to more extensive approaches.

Conclusion The focused sylvian opening is a less-invasive alternative to the classical wide sylvian opening for the microsurgical management of most MCA aneurysms.

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Deep Arteriovenous Malformations in the Basal Ganglia, Thalamus, and Insula: Microsurgical Management, Techniques, and Results

Surgery for Deep AVM-1

Neurosurgery 73:417–429, 2013

Arteriovenous malformations (AVMs) in the basal ganglia, thalamus, and insula are considered inoperable given their depth, eloquence, and limited surgical exposure. Although many neurosurgeons opt for radiosurgery or observation, others have challenged the belief that deep AVMs are inoperable. Further discussion of patient selection, technique, and multimodality management is needed.

OBJECTIVE: To describe and discuss the technical considerations of microsurgical resection for deep-seated AVMs.

METHODS: Patients with deep AVMs who underwent surgery during a 14-year period were reviewed through the use of a prospective AVM registry.

RESULTS: Microsurgery was performed in 48 patients with AVMs in the basal ganglia (n = 10), thalamus (n = 13), or insula (n = 25). The most common Spetzler-Martin grade was III2 (68%). Surgical approaches included transsylvian (67%), transcallosal (19%), and transcortical (15%). Complete resection was achieved in 34 patients (71%), and patients with incomplete resection were treated with radiosurgery. Forty-five patients (94%) were improved or unchanged (mean follow-up, 1.6 years).

CONCLUSION: This experience advances the notion that select deep AVMs may be operable lesions. Patients were highly selected for small size, hemorrhagic presentation, young age, and compactness—factors embodied in the Spetzler-Martin and Supplementary grading systems. Overall, 10 different approaches were used, exploiting direct, transcortical corridors created by hemorrhage or maximizing anatomic corridors through subarachnoid spaces and ventricles that minimize brain transgression. The same cautious attitude exercised in selecting patients for surgery was also exercised in deciding extent of resection, opting for incomplete resection and radiosurgery more than with other AVMs to prioritize neurological outcomes.

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Surgical management and outcomes of petroclival meningiomas: a single-center case series of 259 patients

Petroclival meningioma outcomes

Acta Neurochir (2013) 155:1367–1383

Surgical management of petroclival meningiomas is challenging. Various and inconsistent outcome and prognostic factors of the lesions have been evaluated previously. In the present study, the surgical outcome, philosophy, and experience of petroclival meningiomas are detailed based on a large patient series.

Methods A series of 259 patients with petroclival meningiomas (70 males and 189 females) were surgically treated. Clinical charts and radiographs were reviewed. Follow-up results were evaluated.

Results The preoperative Karnofsky Performance Scale (KPS) score was 74.2±10.5. The mean tumor size was 4.3±1.0 cm. The gross total resection (GTR) rate was 52.5 %. During a mean follow-up period of 55.3 months, recurrence/progression (R/P) occurred in 11 patients. The recent KPS score was 78.4±22.7, it improved in 139 (57.2 %) patients and stabilized in 53 (21.8 %) patients, and 201 (82.7 %) patients lived independently. The risk factors affecting the KPS score included (but were not limited to) age≥60, preoperative KPS≤60, and brainstem edema. The adverse factors contributing to R/P-free survival included (but were not limited to) non-total resection and the absence of the subarachnoid space. The R/P-free survival rate was 94.5 % at 5 years and 91.2 % at 9 years. The overall survival rate was 94.7 % at 5 years and 94.7 % at 9 years.

Conclusions Favorable outcomes from petroclival meningiomas could be achieved by microsurgery. Neurological function and quality of life were prioritized, and GTR was attempted. Risk factors should be considered in surgical schemes, and tumor recurrence should be aggressively monitored and treated.

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Surgical treatment of tentorial dural arteriovenous fistulae located around the tentorial incisura

Surgical treatment of tentorial dural arteriovenous fistulae

Neurosurg Rev (2013) 36:429–435

Tentorial dural arteriovenous fistulae (DAVF) are relatively uncommon and are the most dangerous type of DAVF. Because of a high incidence of hemorrhage and subsequent neurological deficits, treatment is mandatory.

A consecutive series of nine surgically treated patients with symptomatic tentorial DAVF were analyzed in this study. All lesions were located around the tentorial incisura and were treated microsurgically using a subtemporal approach in eight cases and a supracerebellar approach in one case. The dural bases of the lesions were located adjacent to the tentorial edge in six patients and the tentorial apex in three patients.

Complete obliteration was achieved in all treated tentorial DAVF. In one patient, the torcular fistula remained untreated without cortical venous reflux. Postoperative asymptomatic temporal lobe hemorrhage was diagnosed in one patient with a tentorial apex DAVF; however, no new neurological symptoms were present after surgical treatment.

The subtemporal approach for unilateral tentorial DAVF is a favorable and direct approach for the highly skilled surgeon. Perimesencephalic venous dilatation or varix is an important finding onMRI to help localize tentorial DAVF in the tentorial edge or apex.

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Foramen magnum meningiomas: To drill or not to drill the occipital condyle?

FMM

Surg Neurol Int 2013;4:73

Despite the development of microsurgery and cranial base techniques, the surgical management of Foramen Magnum Meningiomas (FMM) continues to be a technical challenge to neurosurgeons. Controversy concerning the utility of systematic condyle drilling for approaching FMM has been raised. Our aim was to describe the surgical technique, analyze its safety, and the postoperative outcome in 12 consecutive FMM patients.

Methods: From 1986 to 2011,12 patients with FMM underwent operations in the Department of Neurosurgery at Servidores do Estado Hospital and in a private clinic. All patients were operated using a standard suboccipital craniectomy, preserving the occipital condyle, opening of the Foramen Magnum, and ipsilateral removal of the posterior arch of C1.

Results: There was no operative mortality, nine patients achieved Glasgow Outcome Scale 4 or 5. Condylar resection was not deemed necessary in any case. Gross total resection was achieved in nine patients. After surgery, four patients developed lower cranial nerve weakness. There was no significant postoperative complication in the remaining patients. The average follow-up is 8.2 years.

Conclusion: The vast majority of FMM can be safely removed with a retrocondylar lateral suboccipital approach without condylar resection, using meticulous microsurgical techniques.

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Brainstem gangliogliomas: a retrospective series

Brainstem gangliogliomas- a retrospective series

J Neurosurg 118:884–888, 2013

The authors retrospectively analyzed data on brainstem gangliogliomas treated in their department and reviewed the pertinent literature to foster understanding of the preoperative characteristics, management, and clinical outcomes of this disease.

Methods. In 2006, the authors established a database of treated lesions of the posterior fossa. The epidemiology findings, clinical presentations, radiological investigations, pathological diagnoses, management, and prognosis for brainstem gangliogliomas were retrospectively analyzed.

Results. Between 2006 and 2012, 7 patients suffering from brainstem ganglioglioma were treated at the West China Hospital of Sichuan University. The mean age of the patients, mean duration of symptoms prior to diagnosis, and mean duration of follow-up were 28.6 years, 19.4 months, and 38.1 months, respectively. The main presentations were progressive cranial nerve deficits and cerebellar signs. Subtotal resection was achieved in 2 patients, and partial resection in 5. All tumors were pathologically diagnosed as WHO Grade I or II ganglioglioma. Radiotherapy and adjuvant chemotherapy were not administered. After 21–69 months of follow-up, patient symptoms were resolved or stable without aggravation, and MRI showed that the size of residual lesions was unchanged without progression or recurrence.

Conclusions. The diagnosis of brainstem ganglioglioma is of great importance given its favorable prognosis. The authors recommend the maximal safe resection followed by close observation without adjuvant therapy as the optimal treatment for this disease.

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Cavernous Malformation of Brainstem, Thalamus, and Basal Ganglia: A Series of 176 Patients

Cavernous_Malformation_of_Brainstem,_Thalamus,_and

Neurosurgery 72:573–589, 2013

Cavernous malformations (CMs) in deep locations account for 9% to 35% of brain malformations and are surgically challenging.

OBJECTIVE: To study the clinical features and outcomes following surgery for deep CMs and the complication of hypertrophic olivary degeneration (HOD).

METHODS: Clinical records, radiological findings, operative details, and complications of 176 patients with deep CMs were reviewed retrospectively.

RESULTS: Of 176 patients with 179 CMs, 136 CMs were in the brainstem, 27 in the basal ganglia, and 16 in the thalamus. Cranial nerve deficits (51.1%), hemiparesis (40.9%), numbness (34.7%), and cerebellar symptoms (38.6%) presented most commonly. Hemorrhage presented in 172 patients (70 single, 102 multiple). The annual retrospective hemorrhage rate was 5.1% (assuming CMs are congenital with uniform hemorrhage risk throughout life); the rebleed rate was 31.5%/patient per year. Surgical approach depended on the proximity of the CM to the pial or ependymal surface. Postoperatively, 121 patients (68.8%) had no new neurological deficits. Follow-up occurred in 170 patients. Delayed postoperative HOD developed in 9/134 (6.7%) patients with brainstem CMs. HOD occurred predominantly following surgery for pontine CMs (9/10 patients). Three patients with HOD had palatal myoclonus, nystagmus, and oscillopsia, whereas 1 patient each had limb tremor and hemiballismus. At follow-up, 105 patients (61.8%) improved, 44 (25.9%) were unchanged, and 19 (11.2%) worsened neurologically. Good preoperative modified Rankin Score (98.2% vs 54.5%, P = .001) and single hemorrhage (89% vs 77.3%, P , .05) were predictive of good longterm outcome.

CONCLUSION: Symptomatic deep CMs can be resected with acceptable morbidity and outcomes. Good preoperative modified Rankin Score and single hemorrhage are predictors of good long-term outcome.

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Merging machines with microsurgery: clinical experience with neuroArm

Merging machines with microsurgery- clinical experience with neuroArm

J Neurosurg 118:521–529, 2013

It has been over a decade since the introduction of the da Vinci Surgical System into surgery. Since then, technology has been advancing at an exponential rate, and newer surgical robots are becoming increasingly sophisticated, which could greatly impact the performance of surgery. NeuroArm is one such robotic system.

Methods. Clinical integration of neuroArm, an MR-compatible image-guided robot, into surgical procedure has been developed over a prospective series of 35 cases with varying pathology.

Results. Only 1 adverse event was encountered in the first 35 neuroArm cases, with no patient injury. The adverse event was uncontrolled motion of the left neuroArm manipulator, which was corrected through a rigorous safety review procedure. Surgeons used a graded approach to introducing neuroArm into surgery, with routine dissection of the tumor-brain interface occurring over the last 15 cases. The use of neuroArm for routine dissection shows that robotic technology can be successfully integrated into microsurgery. Karnofsky performance status scores were significantly improved postoperatively and at 12-week follow-up.

Conclusions. Surgical robots have the potential to improve surgical precision and accuracy through motion scaling and tremor filters, although human surgeons currently possess superior speed and dexterity. Additionally, neuroArm’s workstation has positive implications for technology management and surgical education. NeuroArm is a step toward a future in which a variety of machines are merged with medicine.

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Microsurgical Management of Jugular Foramen Schwannomas

Primary Jugular Foramen Meningioma- Imaging Appearance and Differentiating Features1

Neurosurgery 72:42–46, 2013

Jugular foramen schwannomas are uncommon and surgically challenging lesions.

OBJECTIVE: To determine the importance of surgical technique on morbidity and recurrence of jugular foramen schwannomas.

METHODS: A retrospective review and case-control analysis of a single-senior-surgeon series of 81 patients with surgically treated jugular foramen schwannomas was performed, focusing on operative technique. Patients undergoing an aggressive, total tumor resection (series 1) were compared with those undergoing more conservative resection focusing on preserving the pars nervosa (series 2).

RESULTS: There was a statistically significant (P = .04) decrease in permanent deficits of the cranial nerve 9/10 complex with a conservative technique. Recurrence was seen in 3 patients (5.7%) in series 1 and in 3 patients (10.7%) in series 2 (P = .36). Recurrence was treated with reoperation in 1 patient, radiation in 1 patient, and observation in the others.

CONCLUSION: Although radical gross total resection is desirable, it is not optimal for cranial nerve preservation in patients with jugular foramen schwannomas. A more conservative approach resulted in a statistically significant decrease in lower cranial nerve deficits. There was a nonstatistically significant trend toward increasing recurrence, which may be treated with multiple modality therapy in the modern era.

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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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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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Fusion of MRI/MRA images for navigation in AVM surgery

Neurosurg Focus 32 (5):E7, 2012. (http://thejns.org/doi/abs/10.3171/2012.1.FOCUS127)

Microsurgical resection of arteriovenous malformations (AVMs) is facilitated by real-time image guidance that demonstrates the precise size and location of the AVM nidus. Magnetic resonance images have routinely been used for intraoperative navigation, but there is no single MRI sequence that can provide all the details needed for characterization of the AVM. Additional information detailing the specific location of the feeding arteries and draining veins would be valuable during surgery, and this detail may be provided by fusing MR images and MR angiography (MRA) sequences.

The current study describes the use of a technique that fuses contrast-enhanced MR images and 3D time-of-flight MR angiograms for intraoperative navigation in AVM resection.

Methods. All patients undergoing microsurgical resection of AVMs at the Dartmouth Cerebrovascular Surgery Program were evaluated from the surgical database. Between 2009 and 2011, 15 patients underwent surgery in which this contrast-enhanced MRI and MRA fusion technique was used, and these patient form the population of the present study.

Results. Image fusion was successful in all 15 cases. The additional data manipulation required to fuse the image sets was performed on the morning of surgery with minimal added setup time. The navigation system accurately identified feeding arteries and draining veins during resection in all cases. There was minimal imaging-related artifact produced by embolic materials in AVMs that had been preoperatively embolized. Complete AVM obliteration was demonstrated on intraoperative angiography in all cases.

Conclusions. Precise anatomical localization, as well as the ability to differentiate between arteries and veins during AVM microsurgery, is feasible with the aforementioned MRI/MRA fusion technique. The technique provides important information that is beneficial to preoperative planning, intraoperative navigation, and successful AVM resection.

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Fusion of MRI/MRA images for navigation in AVM surgery

Neurosurg Focus 32 (5):E7, 2012. http://thejns.org/doi/abs/10.3171/2012.1.FOCUS127

Microsurgical resection of arteriovenous malformations (AVMs) is facilitated by real-time image guidance that demonstrates the precise size and location of the AVM nidus. Magnetic resonance images have routinely been used for intraoperative navigation, but there is no single MRI sequence that can provide all the details needed for characterization of the AVM. Additional information detailing the specific location of the feeding arteries and draining veins would be valuable during surgery, and this detail may be provided by fusing MR images and MR angiography (MRA) sequences. The current study describes the use of a technique that fuses contrast-enhanced MR images and 3D time-of-flight MR angiograms for intraoperative navigation in AVM resection.

Methods. All patients undergoing microsurgical resection of AVMs at the Dartmouth Cerebrovascular Surgery Program were evaluated from the surgical database. Between 2009 and 2011, 15 patients underwent surgery in which this contrast-enhanced MRI and MRA fusion technique was used, and these patient form the population of the present study.

Results. Image fusion was successful in all 15 cases. The additional data manipulation required to fuse the image sets was performed on the morning of surgery with minimal added setup time. The navigation system accurately identified feeding arteries and draining veins during resection in all cases. There was minimal imaging-related artifact produced by embolic materials in AVMs that had been preoperatively embolized. Complete AVM obliteration was demonstrated on intraoperative angiography in all cases.

Conclusions. Precise anatomical localization, as well as the ability to differentiate between arteries and veins during AVM microsurgery, is feasible with the aforementioned MRI/MRA fusion technique. The technique provides important information that is beneficial to preoperative planning, intraoperative navigation, and successful AVM resection.

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Intramedullary spinal cord cavernous malformations

J Neurosurg Spine 16:308–314, 2012. DOI: 10.3171/2011.11.SPINE11536

Intramedullary spinal cord cavernous malformations (CMs), once thought to be extremely rare, have been diagnosed more frequently since the advent of MR imaging. In the literature, however, only a few studies include more than 10 cases. The aim of this study was to discuss the clinical presentation of intramedullary spinal cord CMs and the outcome of microsurgery for these histologically benign but clinically progressive lesions.

Methods. The authors retrospectively reviewed the records of 20 patients who underwent microsurgery for intramedullary spinal cord CMs. All patients had undergone pre- and postoperative MR imaging, and they were all treated using microsurgical resection. The diagnosis of spinal cord CMs was based on pathological criteria. The pre- and postoperative neurological states of the patients were classified according to the McCormick scale and Frankel scale. The microsurgical outcomes are presented and discussed.

Results. In most cases, CMs can be diagnosed on the basis of MR imaging findings, since these lesions have certain characteristic imaging patterns. Patients with intramedullary spinal cord CMs may present with either a rapid, acute onset of symptoms or slow, progressive neurological decline. The CMs in 19 of 20 patients in this series were totally resected, and most patients neurologically improved postoperatively. As previously reported, the authors confirm that the treatment of choice for symptomatic intramedullary CMs is total removal of the lesion to avoid recurrence and the possibility of further hemorrhage.

Conclusions. This study has defined the clinical features of symptomatic intramedullary spinal cord CMs. Surgery is the mainstay treatment. Surgical outcome is associated with low mortality with a high probability of functional recovery, especially when symptoms are not severe and are of relatively recent onset.

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Trigeminal Schwannomas: Skull Base Approaches and Operative Results in 105 Patients

Neurosurgery 70[ONS Suppl 1]:ons132–ons144, 2012 DOI: 10.1227/NEU.0b013e31822efb21

Trigeminal schwannomas make up 0.8% to 8% of all intracranial schwannomas.

OBJECTIVE: To analyze our surgical experience with trigeminal schwannomas.

METHODS: We performed 107 operations on 105 patients harboring trigeminal schwannomas over the past 30 years. We classified the tumors as peripheral, ganglion cavernous, posterior fossa root, and dumbbell types according to the portion of the nerve that gave rise to the tumor.

RESULTS: Fourteen were peripheral-type tumors (13.1%), 39 (36.4%) were ganglion cavernous type, 22 (20.6%) were posterior fossa root type, and 32 (30.0%) were dumbbell type. Sixty-five tumors were solid, 35 were mixed, and only 7 were cystic. Among solid tumors, 14 were vascular, fibrous, and adherent to adjacent structures. Total or near-total removal was performed in 86 cases (81.9%), and subtotal removal was achieved in 18 (17.1%). The most common symptom was facial hypesthesia, occurring in 69 patients. This symptom improved in 11 patients, persisted in 50 patients, and worsened in 8 patients after surgery. New postoperative hypesthesia was observed in 8 patients. The second most common symptom was facial pain, observed in 24 patients. Facial pain subsided in 22 and persisted in 2 patients after surgery. Diplopia was observed in 21 patients. This symptom improved postoperatively in 14 patients, persisted in 6 patients, and worsened in 1 patient.

CONCLUSION: The present series demonstrates acceptable results using microsurgical treatment to remove trigeminal schwannomas. Pain and diplopia may be relieved after surgery; however, hypesthesia frequently remains or may be worsened by surgery.

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