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Daily bibliographic review of the Neurosurgery Department. La Fe University Hospital. Valencia, Spain

Which Cerebral Cavernous Malformations are Most Difficult to Dissect From Surrounding Eloquent Brain Tissue?

Neurosurgery 81:498–503, 2017

Cerebral cavernous malformations (CCM) may lead to repetitive intracerebral hemorrhage. In selected cases, a surgical resection is indicated.

OBJECTIVE: To identify magnetic resonance imaging (MRI) features of CCM that correlate with the difficulty of dissection and postoperative outcome.

METHODS: This study prospectively analyzed pre- and postoperative MRI features, intraoperative findings (surgical questionnaire), and postoperative outcome of 41 patients with eloquent CCM. Based on the results of the surgeon’s questionnaire and postoperative MRI findings, all surgical procedureswere dichotomized in a “difficult”(groupA) or “not difficult” (group B) lesion dissection. Based on the correlation of preoperative MRI features with groups A and B, a 3-tiered classification was established and tested for sensitivity and specificity.

RESULTS: In 22 patients, dissection of the lesion was rated difficult. This was significantly correlated with amount of postoperative diffusion restriction on MRI (P=.001) and postoperative outcome(P=.05). Various preoperative MRI featureswere tested for correlation and combined in a 3-tiered classification. Receiver operating characteristics revealed excellent and good results for predicting difficulty of dissection for the different classification types.

CONCLUSION: We provide a meticulous analysis and new classification of preoperative MRI features that seem to be involved in the microsurgical resection of CCM.

The Superior Cerebellar Artery Aneurysm: A Posterior Circulation Aneurysm with Favorable Microsurgical Outcomes

Neurosurgery 80:908–916, 2017

Superior cerebellar artery (SCA) aneurysms are usually grouped with aneurysms that arise from the upper basilar artery or more broadly, the posterior circulation. However, the SCA aneurysm has distinctive anatomy that facilitates safe surgical management, notably few associated perforating arteries, and excellent exposure in the carotid-oculomotor triangle.

OBJECTIVE: To demonstrate the outcomes of patients treated with microsurgery in a continuous surgical series.

METHODS: Sixty-two patients harboring 63 SCA aneurysmswere retrospectively reviewed from a prospectively maintained database, focusing on clinical characteristics, surgical techniques, and clinical outcomes.

RESULTS: Of 31 patients (49%) presenting with subarachnoid hemorrhage, the SCA aneurysm was the source in 16 (25%). Thirty-three aneurysms were complex (52%) and 43 patients (59%) had multiple aneurysms. Fifty-seven SCA aneurysms (90.5%) were clipped and 5 were bypassed/trapped or wrapped. Complete angiographic occlusion was achieved in 91.7%. Permanent neurological morbidity occurred in 3 patients and 3 patients that presented in coma after subarachnoid hemorrhage died. All patients with “simple” aneurysms and without subarachnoid hemorrhage had improved or unchangedmodified Rankin scale scores. Overall, outcomes were stable or improved in 82.5% of patients.

CONCLUSION: SCA aneurysms are favorable for microsurgical clipping with low rates of permanent morbidity and mortality. Microsurgery should be considered alongside endovascular techniques as a treatment option in many patients.

Cystic Craniopharyngiomas: Microsurgical or Stereotactic Treatment?

Neurosurgery (2017) 80 (5): 733-743

Prognosis and treatment of cystic craniopharyngiomas are poorly defined.

OBJECTIVE: To analyze progression-free survival (PFS) and safety profile of cystic craniopharyngiomas undergoing resection or minimally invasive drainage procedures. We compared further outcome measurements for cystic and solid tumors undergoing resection to elucidate the impact of the initial tumor composition on both PFS and the toxicity profile.

METHODS: All patients with craniopharyngiomas consecutively treated between 1999 and 2014 were included. A treatment decision in favor of microsurgery or stereotactic treatment was made interdisciplinarily. For stereotactic drainage, a catheter was implanted, allowing both permanent upstream (into ventricular spaces) and downstream (into prepontine cistern) drainage. Study endpoints were tumor progression, functional outcome, and treatment toxicity. Functional endocrinological and visual outcome analyses referred to data obtained preoperatively and 6 weeks after treatment. The Kaplan-Meier method was used for survival analysis. Prognostic factors were obtained from proportional hazard models.

RESULTS: Seventy-nine patients were included. The distribution of clinical and tumor-related data was well balanced among patients with solid (n = 35) and cystic (n = 44) tumors and those undergoing microsurgical or stereotactic treatment. Cystic tumors had shorter PFS (5-year PFS: 53.6% vs 66.8%, P= .10) and needed significantly more therapeutic interventions, which was independent of the initial treatment mode. The endocrinological deterioration rate was high for both solid and cystic tumors after microsurgery (59.4% and 85.7%, respectively), whereas it was significantly lower for cystic tumors undergoing stereotactic treatment (23.1%, P < .001).

CONCLUSION: Stereotactic bidirectional drainage of cystic craniopharyngiomas is effective and provides a better endocrinological outcome than conventional microsurgery.

Microsurgery for cerebral arteriovenous malformations: subgroup outcomes in a consecutive series of 288 cases

J Neurosurg 126:1056–1063, 2017

The objective of this study was to review the outcomes after microsurgical resection of cerebral arteriovenous malformations (AVMs) from a consecutive single-surgeon series. Clinical and imaging data were analyzed to address the following questions concerning AVM treatment in the post-ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations) era. 1) Are the patients who present with unruptured or ruptured AVMs doing better at long-term follow-up? 2) Is the differentiation between Ponce Class A (Spetzler-Martin Grade I and II) patients versus Ponce Class B and C patients (Spetzler-Martin Grade III and IV) meaningful and applicable to surgical practice? 3) How did the ARUBA-eligible patients of this surgical series compare with the results reported in ARUBA?

METHODS Two hundred eighty-eight patients with cerebral AVMs underwent microsurgical resection between 1983 and 2012 performed by the same surgeon (J.S.). This is a prospective case collection study that represents a consecutive series. The results are based on prospectively collected, early-outcome data that were supplemented by retrospectively collected, follow-up data for 94% of those cases. The analyzed data included the initial presentation, Spetzler-Martin grade, obliteration rates, surgical and neurological complications, and frequency of pretreatment with embolization or radiosurgery. The total cohort was compared using “small-AVM,” Spetzler-Martin Grade I and II, and ARUBA-eligible AVM subgroups.

RESULTS The initial presentation was hemorrhage in 50.0% and seizures in 43.1% of patients. The series included 53 Spetzler-Martin Grade I (18.4%), 114 Spetzler-Martin Grade II (39.6%), 90 Spetzler-Martin Grade III (31.3%), 28 Spetzler- Martin Grade IV (9.7%), and 3 Spetzler-Martin Grade V (1.0%) AVMs. There were 144 unruptured and 104 ARUBAeligible cases. Preembolization was used in 39 cases (13.5%). The occlusion rates for the total series and small AVM subgroup were 99% and 98.7%, respectively. The mean follow-up duration was 64 months. Early neurological deterioration was seen in 39.2% of patients, of which 12.2% had permanent and 5.6% had permanent significant deficits, and the mortality rate was 1.7% (n = 5). Outcome was better for patients with AVMs smaller than 3 cm (permanent deficit in 7.8% and permanent significant deficit in 3.2% of patients) and Ponce Class A status (permanent deficit in 7.8% and significant deficit in 3.2% of patients). Unruptured AVMs showed slightly higher new deficit rates (but 0 instances of mortality) among all cases, and in the small AVM and Ponce Class A subgroups. Unruptured Spetzler-Martin Grade I and II lesions had the best outcome (1.8% permanent significant deficit), and ARUBA-eligible Spetzler-Martin Grade I and II lesions had a slightly higher rate of permanent significant deficits (3.2%).

CONCLUSIONS Microsurgery has a very high cure rate. Focusing microsurgical AVM resection on unruptured lesions smaller than 3 cm or on Spetzler-Martin Grade I and II lesions is a good strategy for minimizing long-term morbidity. Well-selected microsurgical cases lead to better outcomes than with multimodal interventions, as in the ARUBA treatment arm, or conservative treatment alone. Long-term prospective data collection is valuable.

Microsurgery for cerebral arteriovenous malformations: subgroup outcomes in a consecutive series of 288 cases

J Neurosurg 126:1056–1063, 2017

The objective of this study was to review the outcomes after microsurgical resection of cerebral arteriovenous malformations (AVMs) from a consecutive single-surgeon series. Clinical and imaging data were analyzed to address the following questions concerning AVM treatment in the post-ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations) era. 1) Are the patients who present with unruptured or ruptured AVMs doing better at long-term follow-up? 2) Is the differentiation between Ponce Class A (Spetzler-Martin Grade I and II) patients versus Ponce Class B and C patients (Spetzler-Martin Grade III and IV) meaningful and applicable to surgical practice? 3) How did the ARUBA-eligible patients of this surgical series compare with the results reported in ARUBA?

METHODS Two hundred eighty-eight patients with cerebral AVMs underwent microsurgical resection between 1983 and 2012 performed by the same surgeon (J.S.). This is a prospective case collection study that represents a consecutive series. The results are based on prospectively collected, early-outcome data that were supplemented by retrospectively collected, follow-up data for 94% of those cases. The analyzed data included the initial presentation, Spetzler-Mar-tin grade, obliteration rates, surgical and neurological complications, and frequency of pretreatment with embolization or radiosurgery. The total cohort was compared using “small-AVM,” Spetzler-Martin Grade I and II, and ARUBA-eligible AVM subgroups.

RESULTS The initial presentation was hemorrhage in 50.0% and seizures in 43.1% of patients. The series included 53 Spetzler-Martin Grade I (18.4%), 114 Spetzler-Martin Grade II (39.6%), 90 Spetzler-Martin Grade III (31.3%), 28 Spetzler-Martin Grade IV (9.7%), and 3 Spetzler-Martin Grade V (1.0%) AVMs. There were 144 unruptured and 104 ARUBA-eligible cases. Preembolization was used in 39 cases (13.5%). The occlusion rates for the total series and small AVM subgroup were 99% and 98.7%, respectively. The mean follow-up duration was 64 months. Early neurological deterioration was seen in 39.2% of patients, of which 12.2% had permanent and 5.6% had permanent significant deficits, and the mortality rate was 1.7% (n = 5). Outcome was better for patients with AVMs smaller than 3 cm (permanent deficit in 7.8% and permanent significant deficit in 3.2% of patients) and Ponce Class A status (permanent deficit in 7.8% and significant deficit in 3.2% of patients). Unruptured AVMs showed slightly higher new deficit rates (but 0 instances of mortality) among all cases, and in the small AVM and Ponce Class A subgroups. Unruptured Spetzler-Martin Grade I and II lesions had the best outcome (1.8% permanent significant deficit), and ARUBA-eligible Spetzler-Martin Grade I and II lesions had a slightly higher rate of permanent significant deficits (3.2%).

CONCLUSIONS Microsurgery has a very high cure rate. Focusing microsurgical AVM resection on unruptured lesions smaller than 3 cm or on Spetzler-Martin Grade I and II lesions is a good strategy for minimizing long-term morbidity. Well-selected microsurgical cases lead to better outcomes than with multimodal interventions, as in the ARUBA treatment arm, or conservative treatment alone. Long-term prospective data collection is valuable.

Transulcal parafascicular minimally invasive approach to deep and subcortical cavernomas

J Neurosurg 125:1360–1366, 2016

Cavernomas comprise 8%–15% of intracranial vascular lesions, usually supratentorial in location and superficial. Cavernomas in the thalamus or subcortical white matter represent a unique challenge for surgeons in trying to identify and then use a safe corridor to access and resect the pathology.

Previous authors have described specific open microsurgical corridors based on pathology location, often with technical difficulty and morbidity.

This series presents 2 cavernomas that were resected using a minimally invasive approach that is less technically demanding and has a good safety profile. The authors report 2 cases of cavernoma: one in the thalamus and brainstem with multiple hemorrhages and the other in eloquent subcortical white matter. These lesions were resected through a transulcal parafascicular approach with a port-based minimally invasive technique.

In this series there was complete resection with no neurological complications. The transulcal parafascicular minimally invasive approach relies on image interpretation and trajectory planning, intraoperative navigation, cortical cannulation and subcortical space access, high-quality optics, and resection as key elements to minimize exposure and retraction and maximize tissue preservation. The authors applied this technique to 2 patients with cavernomas in eloquent locations with excellent outcomes.

 

Cotton-clipping and cotton-augmentation for aneurysms

cotton-clipping-and-cotton-augmentation-for-aneurysms

J Neurosurg 125:720–729, 2016

To address the challenges of microsurgically treating broad-based, frail, and otherwise complex aneurysms that are not amenable to direct clipping, alternative techniques have been developed. One such technique is to use cotton to augment clipping (“cotton-clipping” technique), which is also used to manage intraoperative aneurysm neck rupture, and another is to reinforce unclippable segments or remnants of aneurysm necks with cotton (“cottonaugmentation” technique). This study reviews the natural history of patients with aneurysms treated with cotton-clipping and cotton-augmentation techniques.

Methods The authors queried a database consisting of all patients with aneurysms treated at Barrow Neurological Institute in Phoenix, Arizona, between January 1, 2004, and December 31, 2014, to identify cases in which cotton-clipping or cotton-augmentation strategies had been used. Management was categorized as the cotton-clipping technique if cotton was used within the blades of the aneurysm clip and as the cotton-clipping technique if cotton was used to reinforce aneurysms or portions of the aneurysm that were unclippable due to the presence of perforators, atherosclerosis, or residual aneurysms. Data were reviewed to assess patient outcomes and annual rates of aneurysm recurrence or hemorrhage after the initial procedures were performed.

Results The authors identified 60 aneurysms treated with these techniques in 57 patients (18 patients with ruptured aneurysms and 39 patients with unruptured aneurysms) whose mean age was 53.1 years (median 55 years; range 24–72 years). Twenty-three aneurysms (11 cases of subarachnoid hemorrhage) were treated using cotton-clipping and 37 with cotton-augmentation techniques (7 cases of subarachnoid hemorrhage). In total, 18 patients presented with subarachnoid hemorrhage. The mean Glasgow Outcome Scale (GOS) score at the time of discharge was 4.4. At a mean follow-up of 60.9 ± 35.6 months (median 70 months; range 10–126 months), the mean GOS score at last follow-up was 4.8. The total number of patient follow-up years was 289.4. During the follow-up period, none of the cotton-clipped aneurysms increased in size, changed in configuration, or rebled. None of the patients experienced early rebleeding. The annual hemorrhage rate for aneurysms treated with cotton-augmentation was 0.52% and the recurrence rate was 1.03% per year. For all patients in the study, the overall risk of hemorrhage was 0.35% per year and the annual recurrence rate was 0.69%.

Conclusions Cotton-clipping is an effective and durable treatment strategy for intraoperative aneurysm rupture and for management of broad-based aneurysms. Cotton-augmentation can be safely used to manage unclippable or partially clipped intracranial aneurysms and affords protection from early aneurysm re-rupture and a relatively low rate of late rehemorrhage.

Optic nerve mobilization to enhance the exposure of the pituitary stalk during craniopharyngioma resection

optic-nerve-mobilization-to-enhance-the-exposure-of-the-pituitary-stalk-during-craniopharyngioma-resection

J Neurosurg 125:683–688, 2016

Preservation of the pituitary stalk and its vasculature is a key step in good postoperative endocrinological outcome in patients with craniopharyngiomas. In this article, the authors describe the surgical technique of medial optic nerve mobilization for better inspection and preservation of the pituitary stalk.

Methods This operative technique has been applied in 3 patients. Following tumor exposure via a frontolateral approach, the pituitary stalk could be seen partially hidden under the optic nerve and the optic chiasm. The subchiasmatic and opticocarotid spaces were narrow, and tumor dissection from the pituitary stalk under direct vision was not possible. The optic canal was therefore unroofed, the falciform ligament was incised, and the lateral part of the tuberculum sellae was drilled medial to the optic nerve. The optic nerve could be mobilized medially to widen the opticocarotid triangle, which enhanced visualization of and access to the pituitary stalk.

Results By using the optic nerve mobilization technique, the tumor could be removed completely, and the pituitary stalk and its vasculature were preserved in all patients. In 2 patients, vision improved after surgery, while in 1 patient it remained normal, as it was before surgery. The hormonal status remained normal after surgery in 2 patients. In the patient with preoperative hormonal deficiencies, improvement occurred early after surgery and hormonal levels were normal after 3 months. No approach-related complications occurred.

Conclusions This early experience shows that this technique is safe and could be used as a complementary step during microsurgery of craniopharyngiomas. It allows for tumor dissection from the pituitary stalk under direct vision. The pituitary stalk can thus be preserved without jeopardizing the optic nerve.

Clinical experience with navigated 3D ultrasound angiography (power Doppler) in microsurgical treatment of brain arteriovenous malformations

Clinical experience with navigated 3D ultrasound angiography (power Doppler) in microsurgical treatment of brain arteriovenous malformations

Acta Neurochir (2016) 158:875–883

We have previously described a method that has the potential to improve surgery of arteriovenous malformations (AVMs). In the present paper, we present our clinical results.

Materials and methods Of 78 patients referred for AVMs to our University Hospital from our geographical catchment region from 2005 through 2013, 31 patients were operated on with microsurgical technique. 3D MR angiography (MRA) with neuronavigation was used for planning. Navigated 3D ultrasound angiography (USA) was used to identify and clip feeders in the initial phase of the operation. None of our patients was embolized preoperatively as part of the surgical procedure. The niduses were extirpated based on the 3D USA. After extirpation, controls were done with 3D USA to verify that the AVMs were completely removed. The Spetzler three-tier classification of the patients was: A: 21, B: 6, C: 4.

Results Sixty-eight feeders were identified on preoperative MRA and DSA and 67 feeders were identified and clipped by guidance of intraoperative 3D USA. Six feeders identified preoperatively were missed by 3D USA, while five preoperatively unknown feeders were found and clipped. The overall average bleeding was 440 ml. There was a significant reduction in average bleeding in the last 15 operations compared to the first 16 (340 vs. 559 ml, p = 0.019). We had no serious morbidity (GOS 3 or less). New deficits due to surgery were two patients with quadrantanopia (one class B and one class C), the latter (C) also acquired epilepsy. One patient (class A) acquired a hardly noticeable paresis in two fingers. One hundred percent angiographic cure was achieved in all patients, as evaluated by postoperative DSA.

Conclusions Navigated intraoperative 3D USA is a useful tool to identify and clip AVM feeders. Microsurgical extirpation assisted by navigated 3D USA is an effective and safe method for removing AVMs.

Analysis of superiorly projecting anterior communicating artery aneurysms

Analysis of superiorly projecting anterior communicating artery aneurysms

Neurosurg Rev (2016) 39:225–235

Superiorly projecting (SP) anterior communicating artery (AComA) aneurysms are typically described as a homogenous group. Clinically and microsurgically, these aneurysms vary in multiple important characteristics.

We propose a microsurgical classification system for these complex aneurysms and review its implications regarding presentation, microsurgical techniques, and outcome.

This retrospective analysis reviews patients undergoing clipping of SP AComA aneurysms (2005–2013). The classification system is based on the virtual plane created by the A2 segments and its relationship to the aneurysm. Aneurysm type was assessed by intraoperative images and videos. Type 1 is defined by bisection of the dome by the virtual plane. Type 2 is defined by dome projection posterior to this plane. Sagittal rotation of the plane defines type 3. We analyzed clinical presentation, morphology, angiographic characteristics, operative technique, and outcome relative to the classification types.

There were 44 SP AComA aneurysms. 3D angiographic images predicted classification type in 83 %. Type 1 presented more often with SAH (95.5 %, p=0.0046). There was no statistically significant difference between the types regarding patient demographics or aneurysm characteristics. In type 2, fenestrated clips were used frequently (87.5 % p=0.0016), and there was higher rate of intraoperative rupture (37.5 %). Although there was no statistically significant difference between the types in respect to HH grade upon presentation, patients with type 2 aneurysms experienced higher rates of poor GOS (50 %).

The proposed classification system for SP AComA aneurysms has implications regarding surgical planning, micro-dissection, clipping, and outcome. Type 2 aneurysms carry significant surgical risk.

Ideal clipping methods for unruptured middle cerebral artery bifurcation aneurysms based on aneurysmal neck classification

MCAb aneurysms clipping

Neurosurg Rev (2016) 39:215–224

Endovascular coiling is widely used for many cerebral aneurysms; however, in cases of middle cerebral artery bifurcation (MCBIF) aneurysms, it is associated with a higher incidence of unfavorable outcomes compared to microsurgical clippings. In this retrospective study, we aimed to investigate the outcomes of microsurgical clipping for unruptured MCBIF aneurysms and determine the ideal clipping methods for different aneurysm subtypes.

From January 2011 to December 2013, 203 aneurysms with saccular shape (<25 mm) were treated by an experienced neurosurgeon. Depending on the involvement of the aneurysmal thin wall, the aneurysm neck was classified as follows: subtype I, limited bifurcation; subtype II, progressed to M1 trunk; subtype III, progressed to M2 trunk; subtype IV, progressed to M1 and one M2 trunk; and subtype V, progressed to M1 and two M2 trunks. The clipping methods included simple, sliding, interlocking, or mixed approaches.

Aneurysm clippings were accomplished without any morbidity in all cases, and seven cases had a minimal neck remnant. The following clipping methods were predominantly used: subtype I, simple (90.2 %) and sliding (8.8 %) (mean = 1.2 clips); subtype II, interlocking (51.4 %), sliding (30.0 %), mixed (15.7 %), and simple (2.9 %) (2.4 clips); subtype III, simple (57.5 %) and sliding (42.5 %) (1.5 clips); subtype IV, interlocking (64.3 %) (2.1 clips), simple (10.7 %), sliding (14.3 %), and mixed (10.7 %); and subtype V, interlocking (50.0 %), sliding (35.7 %), and mixed (14.3 %) methods with multiple clips (2.8 clips).

If an appropriate clipping method is selected according to the neck classification, satisfactory surgical obliteration can be achieved for unruptured MCBIF aneurysms without morbidity.

Surgical management of medium and large petroclival meningiomas: a single institution’s experience of 199 cases with long-term follow-up

Surgical management of medium and large petroclival meningiomas

Acta Neurochir (2016) 158:409–425

Petroclival meningiomas (PCMs) were once regarded as ‘inoperable’ due to their complex anatomy and limited surgical exposure. This study aimed to evaluate the long-term outcomes of surgically treated PCMs larger than 2 cm.

Methods A series of 199 consecutive patients (137 females, 68.8 %) with PCMs larger than 2 cm from between 1993 and 2003 were included. The clinical charts, radiographs, and follow-ups were evaluated.

Results Gross total resection (GTR) was achieved in 111 (55.8 %) patients, subtotal resection (STR) in 65, and partial resection (PR) in 23. Cranial nerve dysfunctions were the most common complications and occurred in 133 (66.8 %) cases. The surgical mortality was 2.0 %. The Karnofsky Performance Scale (KPS) scores significantly decreased 1 month after the operations (preoperative KPS=76.8 and postoperative KPS = 64.8; p = 0.011, Paired-samples t test). Long-term follow-ups were obtained in 142 patients, the follow-up duration was 171.6 months, and the most recent KPS was 83.2. Permanent morbidities remained in 24 patients (18.9 %). Multivariate analysis revealed that brainstem edema and tumors larger than 4 cm in diameter were independent risk factors in terms of outcomes (KPS < 80). The recurrence/ progression rates were 14.5, 31.8, and 53.3 % for the GTR, STR, and PR cases, respectively (p =0.002, Pearson χ2 test). Gamma Knife radiosurgery for the remnants exhibited good tumor control.

Conclusions Favorable outcomes and low mortality were achieved with the microsurgical management of medium and large PCMs; however, the rates of cranial nerves dysfunction remained high. Radically aggressive resection might not be judicious in terms of postoperative morbidity. The preoperative evaluations and intraoperative findings were informative regarding the outcomes. The low follow-up rate likely compromised our findings, and additional consecutive studies were required.

Treatment strategies for dissecting aneurysms of the posterior cerebral artery

Treatment strategies for dissecting aneurysms of the posterior cerebral arteryActa Neurochir (2015) 157:1623–1632

We conducted a systematic review of the literature to evaluate the safety and efficacy of surgical treatment of previously coiled aneurysms.

Methods A comprehensive review of the literature for studies on surgical treatment of previously coiled aneurysms was conducted. For each study, the following data were extracted: patient demographics, initial clinical status, location and size of aneurysms, time interval between initial/last endovascular procedure and surgery, surgical indications, and microsurgical technique.We performed subgroup analyses to compare direct clipping versus coil removal and clipping versus parent vessel occlusion, early (<4 weeks post-coiling) versus late surgery and anterior versus posterior circulation.

Results Twenty-six studies with 466 patients and 471 intracranial aneurysms were included. All of the studies were retrospective and non-comparative case-series. Patients undergoing direct clipping had lower perioperative morbidity (5.0 %, 95%CI=2.6–7.4 %) when compared to those undergoing coil removal and clipping (11.1 %, 95 % CI=5.3–17.0 %) or parent vessel occlusion (13.1 %, 95%CI=4.6–21.6 %) (p=0.05). Patients receiving early surgery (<4 weeks post-coiling) had significantly lower rates of good neurological outcome (77.1 %, 95 % CI=69.3–84.8 %) when compared to those undergoing late surgery (92.1 %, 95 % CI=89.0–95.2 %) (p<0.01). There were higher rates of long-term neurological morbidity in the posterior circulation group (23.1 vs. 4.7 %, p<0.01) as well as long-term neurological mortality (4.4 vs. 2.8 %, p<0.01).

Conclusions Our meta-analysis suggests that surgical treatment is safe and effective. Our data indicate that aneurysms that are amenable to direct clipping have superior outcomes. Late surgery was also associated with better clinical outcomes. Surgery of recurrent posterior circulation aneurysms was associated with high rates of morbidity and mortality. Given the characteristics of the included studies, the quality of evidence of this meta-analysis is limited.

Safety and efficacy of microsurgical treatment of previously coiled aneurysms: a systematic review and meta-analysis

coiledaneurysm

Acta Neurochir (2015) 157:1623–1632

We conducted a systematic review of the literature to evaluate the safety and efficacy of surgical treatment of previously coiled aneurysms.

Methods A comprehensive review of the literature for studies on surgical treatment of previously coiled aneurysms was conducted. For each study, the following data were extracted: patient demographics, initial clinical status, location and size of aneurysms, time interval between initial/last endovascular procedure and surgery, surgical indications, and microsurgical technique. We performed subgroup analyses to compare direct clipping versus coil removal and clipping versus parent vessel occlusion, early (<4 weeks post-coiling) versus late surgery and anterior versus posterior circulation.

Results Twenty-six studies with 466 patients and 471 intracranial aneurysms were included. All of the studies were retrospective and non-comparative case-series. Patients undergoing direct clipping had lower perioperative morbidity (5.0 %, 95%CI=2.6–7.4 %) when compared to those undergoing coil removal and clipping (11.1 %, 95 % CI=5.3–17.0 %) or parent vessel occlusion (13.1 %, 95%CI=4.6–21.6 %) (p=0.05). Patients receiving early surgery (<4 weeks post-coiling) had significantly lower rates of good neurological outcome (77.1 %, 95 % CI=69.3–84.8 %) when compared to those undergoing late surgery (92.1 %, 95 % CI=89.0–95.2 %) (p<0.01). There were higher rates of long-term neurological morbidity in the posterior circulation group (23.1 vs. 4.7 %, p<0.01) as well as long-term neurological mortality (4.4 vs. 2.8 %, p<0.01).

Conclusions Our meta-analysis suggests that surgical treatment is safe and effective. Our data indicate that aneurysms that are amenable to direct clipping have superior outcomes. Late surgery was also associated with better clinical outcomes. Surgery of recurrent posterior circulation aneurysms was associated with high rates of morbidity and mortality. Given the characteristics of the included studies, the quality of evidence of this meta-analysis is limited.

Intraoperative Flow Measurement by Microflow Probe During Surgery for Brain Arteriovenous Malformations

Intraoperative Flow Measurement by Microflow Probe During Surgery for Brain Arteriovenous Malformations

Operative Neurosurgery 11:268–273, 2015

Intraoperative quantitative flow measurement by a microvascular ultrasonic flow probe is an established methodology in aneurysm surgery.

OBJECTIVE: To test the present flow measurement procedure in brain arteriovenous malformation (AVM) surgery.

METHODS: Data from 25 patients with brain AVMs who consecutively underwent microsurgical resection with the assistance of flow measurement by a microflow probe were retrospectively analyzed. Flowmetry was performed on arterial feeders, potentially transit arteries, and venous drainage of AVM in different phases of resection.

RESULTS: A quantitative flow measurement was performed 203 times on 92 vessels. Flowmetry was able to define the flow direction of AVM vessels in all cases, thereby discriminating between arterial feeders and venous drainages, both superficially and deeply located. During AVM dissection, flowmetry identified a transit artery in 12% of cases by detecting a flow drop between 2 points of the same vessel. At the final stage of resection, a residual nidus, potentially missed at surgical dissection, was detected when the flow value of venous drainage was greater than 4 mL/min (20% of patients). Preresection microflow probe measurements were concordant with indocyanine green videoangiography data on AVM angioarchitecture in all cases. No microflow probe– induced AVM vessel injury was reported. Complete AVM resection was achieved in all cases with a low morbidity (modified Rankin Scale score #1).

CONCLUSION: Multistage intraoperative quantitative flow measurement proved to be a feasible, safe, repeatable, and reliable methodology to assist surgery in different phases of AVM resection. Further studies are needed to assess the impact of this approach on AVM patient outcomes.

Validation of the Supplemented Spetzler-Martin Grading System for Brain Arteriovenous Malformations in a Multicenter Cohort of 1009 Surgical Patients

AVM

Neurosurgery 76:25–33, 2015

The supplementary grading system for brain arteriovenous malformations (AVMs) was introduced in 2010 as a tool for improving preoperative risk prediction and selecting surgical patients.

OBJECTIVE: To demonstrate in this multicenter validation study that supplemented Spetzler-Martin (SM-Supp) grades have greater predictive accuracy than Spetzler-Martin (SM) grades alone.

METHODS: Data collected from 1009 AVM patients who underwent AVM resection were used to compare the predictive powers of SM and SM-Supp grades. Patients included the original 300 University of California, San Francisco patients plus those treated thereafter (n = 117) and an additional 592 patients from 3 other centers.

RESULTS: In the combined cohort, the SM-Supp system performed better than SM system alone: area under the receiver-operating characteristics curve (AUROC) = 0.75 (95% confidence interval, 0.71-0.78) for SM-Supp and AUROC = 0.69 (95% confidence interval, 0.65-0.73) for SM (P , .001). Stratified analysis fitting models within 3 different follow-up groupings (,6 months, 6 months-2 years, and .2 years) demonstrated that the SM-Supp system performed better than SM system for both medium (AUROC = 0.71 vs 0.62; P = .003) and long (AUROC = 0.69 vs 0.58; P = .001) follow-up. Patients with SMSupp grades #6 had acceptably low surgical risks (0%-24%), with a significant increase in risk for grades .6 (39%-63%).

CONCLUSION: This study validates the predictive accuracy of the SM-Supp system in a multicenter cohort. An SM-Supp grade of 6 is a cutoff or boundary for AVM operability. Supplemented grading is currently the best method of estimating neurological outcomes after AVM surgery, and we recommend it as a starting point in the evaluation of AVM operability.

Microsurgery for cerebral arteriovenous malformations: postoperative outcomes and predictors of complications in 264 cases

AVM PF

Neurosurg Focus 37 (3):E10, 2014

The authors conducted a study to assess the safety and efficacy of microsurgical resection of arteriovenous malformations (AVMs) and determine predictors of complications.

Methods. A total of 264 patients with cerebral AVMs were treated with microsurgical resection between 1994 and 2010 at the Jefferson Hospital for Neuroscience. A review of patient data was performed, including initial hemorrhage, clinical presentation, Spetzler-Martin (SM) grade, treatment modalities, clinical outcomes, and obliteration rates. Univariate and multivariate analyses were used to determine predictors of operative complications.

Results. Of the 264 patients treated with microsurgery, 120 (45%) patients initially presented with hemorrhage. There were 27 SM Grade I lesions (10.2%), 101 Grade II lesions (38.3%), 96 Grade III lesions (36.4%), 31 Grade IV lesions (11.7%), and 9 Grade V lesions (3.4%). Among these patients, 102 (38.6%) had undergone prior endovascular embolization. In all patients, resection resulted in complete obliteration of the AVM. Complications occurred in 19 (7.2%) patients and resulted in permanent neurological deficits in 5 (1.9%). In multivariate analysis, predictors of complications were increasing AVM size (OR 3.2, 95% CI 1.5–6.6; p = 0.001), increasing number of embolizations (OR 1.6, 95% CI 1.1–2.2; p = 0.01), and unruptured AVMs (OR 2.7, 95% CI 1–7.2; p = 0.05).

Conclusions. Microsurgical resection of AVMs is highly efficient and can be undertaken with low rates of morbidity at high-volume neurovascular centers. Unruptured and larger AVMs were associated with higher complication rates.

Retrosigmoid removal of small acoustic neuroma: curative tumor removal with preservation of function

Retrosigmoid removal of small acoustic neuroma

J Neurosurg 121:554–563, 2014

Management of small acoustic neuromas (ANs) consists of 3 options: observation with imaging followup, radiosurgery, and/or tumor removal. The authors report the long-term outcomes and preservation of function after retrosigmoid tumor removal in 44 patients and clarify the management paradigm for small ANs.

Methods. A total of 44 consecutively enrolled patients with small ANs and preserved hearing underwent retrosigmoid tumor removal in an attempt to preserve hearing and facial function by use of intraoperative auditory monitoring of auditory brainstem responses (ABRs) and cochlear nerve compound action potentials (CNAPs). All patients were younger than 70 years of age, had a small AN (purely intracanalicular/cerebellopontine angle tumor ≤ 15 mm), and had serviceable hearing preoperatively. According to the guidelines of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology–Head and Neck Surgery Foundation, preoperative hearing levels of the 44 patients were as follows: Class A, 19 patients; Class B, 17; and Class C, 8. The surgical technique for curative tumor removal with preservation of hearing and facial function included sharp dissection and debulking of the tumor, reconstruction of the internal auditory canal, and wide removal of internal auditory canal dura.

Results. For all patients, tumors were totally removed without incidence of facial palsy, death, or other complications. Total tumor removal was confirmed by the first postoperative Gd-enhanced MRI performed 12 months after surgery. Postoperative hearing levels were Class A, 5 patients; Class B, 21; Class C, 11; and Class D, 7. Postoperatively, serviceable (Class A, B, or C) and useful (Class A or B) levels of hearing were preserved for 84% and 72% of patients, respectively. Better preoperative hearing resulted in higher rates of postoperative hearing preservation (p = 0.01); preservation rates were 95% among patients with preoperative Class A hearing, 88% among Class B, and 50% among Class C. Reliable monitoring was more frequently provided by CNAPs than by ABRs (66% vs 32%, p < 0.01), and consistently reliable auditory monitoring was significantly associated with better rates of preservation of useful hearing. Long-term follow-up by MRI with Gd administration (81 ± 43 months [range 5–181 months]; median 7 years) showed no tumor recurrence, and although the preserved hearing declined minimally over the long-term postoperative follow-up period (from 39 ± 15 dB to 45 ± 11 dB in 5.1 ± 3.1 years), 80% of useful hearing and 100% of serviceable hearing remained at the same level.

Conclusions. As a result of a surgical technique that involved sharp dissection and internal auditory canal reconstruction with intraoperative auditory monitoring, retrosigmoid removal of small ANs can lead to successful curative tumor removal without long-term recurrence and with excellent functional outcome. Thus, the authors suggest that tumor removal should be the first-line management strategy for younger patients with small ANs and preserved hearing.

Hearing preservation surgery for vestibular schwannomas via the retrosigmoid transmeatal approach

Hearing preservation surgery in VS-1

Neurosurg Rev (2014) 37:431–444

Maximum tumor extirpation with preservation of the facial and cochlear nerve function is the goal of surgery for vestibular schwannoma. To preserve cochlear nerve function, the surgeon must employ a detailed knowledge of microanatomy, precise microsurgical techniques, and persistence. This paper describes the “pearls” of surgical techniques based on the anatomical study inside the mastoid from the view of the retrosigmoid transmeatal approach.

A total of 592 consecutive patients underwent surgical removal of unilateral vestibular schwannoma (VS) between January 1994 and December 2009. The hearing preservation rate was 53.7 % for large vestibular schwannomas (>20 mm in diameter) and 74.1 % for tumors of all sizes.

The key procedures for hearing preservation surgery are as follows: bloodless microdissection, sufficient coring-debulking, capsular elevation to locate the facial and cochlear nerves both electrophysiologically and by visual observation, sharp dissection of the facial and cochlear nerves, and avoidance of heat and mechanical injury to the nerves, the internal auditory artery, and the brain stem. Besides these techniques, appropriate instruments are essential to preserve hearing.

The function of the facial and cochlear nerves should be the foremost concern. Meticulous techniques and the knowledge of microsurgical anatomy lead to hearing preservation with maximum tumor removal.

 

Operative management of trigeminal neuromas

trigeminal neuroma

Acta Neurochir (2014) 156:1105–1114

The trigeminal schwannoma is the second most common intracranial schwannoma. Their proximity to the critical skull base neural and vascular structures increases the complexity of surgical treatment. The aim of this study was to better understand the surgical approaches and the prognosis, as well as to assess the optimum therapeutic schedule.

Methods This was a retrospective study of 55 patients with trigeminal schwannomas who visited our department between Jan 2007 and Jan 2012. We analyzed the clinical and radiological presentation, tumor characteristics, surgical approaches, the prognosis.

Results The patients were 30 women and 25 men of mean age 36 years (range, 6–66 years) who received postoperative neurological and neuroradiological follow-up. The tumor was located in the middle fossa (type A) in 13 cases, in the posterior fossa (type B) in ten cases, in the middle and posterior fossae (type C) in 21 cases, and in the branches of the trigeminal nerve (type D) in 11 cases. The most common symptom was facial hypesthesia or numbness in 36 patients (65%) . Total and nearly total tumor resection was achieved in 51 cases (93 %). Three patients (5 %) had worsening of preexisting deficits and there was no perioperative mortality. With an average follow-up period of 35 months, facial hypesthesia persisted in 26 patients (72 %),and improved in ten patients (28 %). Facial pain was relieved in 11 patients (100 %). There has been a recurrence in one case (2%) and all patients resumed independent and social reintegration.

Conclusion This study demonstrates radical surgery with excellent neurological outcomes is the primary treatment of trigeminal schwannomas. Appropriate selection of surgical approach according to tumor types is highly important and necessary. The preoperative facial pain could be relieved, hypesthesia frequently remains or could even be worsened after surgery.

Neurosurgery Department. “La Fe” University Hospital. Valencia, Spain

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