Neurosurgery 72:428–436, 2013
Giant middle cerebral artery (MCA) aneurysms pose management challenges.
OBJECTIVE: To review the outcomes of patients with giant MCA aneurysms not amenable to clipping or vessel reconstruction treated with extracranial-intracranial (EC-IC) bypass and vessel sacrifice.
METHODS: We retrospectively reviewed a database of aneurysms treated at our institution between 1983 and 2011.
RESULTS: Sixteen patients (11 males, 5 females) were identified. There were 10 saccular, 4 fusiform, and 2 serpentine aneurysms. The aneurysms predominantly involved the M1 segment in 5 cases, M2 in 9 cases, and both M1 and M2 in 2 cases. The EC-IC bypasses performed included 13 superficial temporal artery-MCA, 1 saphenous vein graft-MCA, and 2 radial artery grafts-MCA. The postoperative bypass patency rate was 93.8% (15/16). There were 3 cerebrovascular accidents (18.8%), but no perioperative deaths (0% mortality). The mean follow-up was 58.4 months (range, 1-265; median, 23.5 months). In 75% (12/16) of cases the aneurysms were occluded successfully. A small residual was noted in 3 cases with the use of this treatment strategy, and they were re-treated. In a fourth case treated with partial distal occlusion, reduced flow through the aneurysm was noted postoperatively, but the patient did not undergo further treatment. The mean modified Rankin scale and mean Glasgow Outcome Scale scores at last follow-up were 1.6 (range, 1-4; median, 1) and 4.8 (range, 3-5; median, 5), respectively.
CONCLUSION: Giant MCA aneurysms are challenging lesions. EC-IC bypass with parent vessel occlusion can provide a durable form of treatment with acceptable rates of morbidity and mortality.
Neurosurgery 72:437–442, 2013
Recent advancements in microsurgical techniques and instrumentation have allowed the development of the keyhole approach in aneurysm surgery.
OBJECTIVE: To compare the safety, efficacy, and 1-year clinical outcome of supraorbital keyhole and standard pterional approaches for ruptured anterior circulation aneurysms.
METHODS: A total of 87 patients underwent surgical clipping, 40 through the pterional and 47 through the supraorbital keyhole approach. Baseline demographics, operative time, procedural complications, and 1-year patient outcome were retrospectively compared.
RESULTS: The 2 groups were comparable with respect to baseline characteristics, with the exception of a higher proportion of small aneurysms (,7 mm) in the supraorbital group (70.2% vs 37.5%, P = .002). Total operative time was significantly shorter in the supraorbital group (205 minutes, P , .001) compared with the pterional group (256 minutes). The rate of procedural complications was lower in patients treated through the pterional (17.5%) vs the supraorbital approach (23.4%, P = .4). Intraoperative aneurysm ruptures occurred more frequently in the supraorbital group (10.6% vs 2.5%). No patient experienced early or late rebleeding in either group. One year after treatment, 75% (30/40) of patients achieved a favorable outcome (Glasgow Outcome Scale IV or V) in the pterional group vs 76.6% (36/47) in the supraorbital group (P = .8).
CONCLUSION: The rate of procedural complications may be higher with the supraorbital keyhole approach, but overall patient outcomes appear to be comparable. The pterional approach is a simple, reliable, and efficient procedure. The keyhole approach may be an acceptable alternative for neurosurgeons who have gained sufficient experience with the technique, especially for small noncomplex aneurysms.
Acta Neurochir (2013) 155:217–222
Fenestrations of intracranial arteries are variants resulting from incomplete fusion of vessels during development with unknown clinical significance. They are best visualised with 3D rotational angiography (3DRA).
Objective In a prospective consecutive series of patients with suspected aneurysms, 3DRA was performed to identify not only the potential bleeding source but also to assess the frequency and location of any fenestrations of intracranial arteries.
Methods In 287 consecutive patients with possible intracranial aneurysms (accidental discovery or previous history of SAH), 3DRAs were prospectively performed, and the location of subarachnoid haemorrhage was assessed by CT.
Results Of 174 patients presenting with SAH, 153 had saccular aneurysms, and in 21 cases (12.1 %), no source of bleeding was found. In 20 of these 21 patients with “unexplained SAH” (95.2 %) an arterial fenestration was detected in the neighbourhood of the clot. The incidence of fenestration in the 153 aneurysmal SAH patients was 22.9 %, and it was 23.3 % in 266 patients with intracranial aneurysms (113 accidental and 153 ruptured).
Conclusions Arterial fenestration was detected in 22.9 % of ruptured cerebral aneurysms, in contrast with 95.2 % in patients with unexplained SAH, the difference being statisctically significant (p<0.01). Fenestration is a developmental defect, a structural wall weakness possibly making the vessel prone to rupture. Its incidence of nearly 100 % may suggest a connection with idiopathic SAH. The presented data indicate that arterial fenestrations are generally overlooked, and they can be considered as one of the candidates for the source of idiopathic SAH.
J Neurosurg 118:58–62, 2013
A small percentage of patients will develop a completely new or de novo aneurysm after discovery of an initial aneurysm. The natural history of these lesions is unknown. The authors undertook this statistical evaluation a large cohort of patients with both ruptured and unruptured de novo aneurysms with the aim of analyzing risk factors for rupture and estimating a risk of subarachnoid hemorrhage (SAH).
Methods. A review of a prospectively maintained database of all aneurysm patients treated by the vascular neurosurgery service of Goodman Campbell Brain and Spine from 1976–2010 was performed. Of the 4718 patients, 611 (13%) had longterm follow-up imaging. The authors identified 27 patients (4.4%) with a total of 32 unruptured de novo aneurysms from routine surveillance imaging. They identified another 10 patients who presented with a new SAH from a de novo aneurysm after treatment of their original aneurysm. The total study group was thus 37 patients with a total of 42 de novo aneurysms. The authors then compared the 27 patients with incidentally discovered aneurysms with the 10 patients with SAH. A statistical analysis was performed, comparing the 2 groups with respect to patient and aneurysm characteristics and risk factors.
Results. Thirty-seven patients were identified as having true de novo aneurysms. This group had a female predominance and a high percentage of smokers. These 37 patients had a total of 42 de novo aneurysms. Ten of these 42 aneurysms hemorrhaged. De novo aneurysms in both the SAH and non-SAH group were anatomically small (< 10 mm). The estimated risk of hemorrhage over 5 years was 14.5%, higher than the expected SAH risk of small, unruptured aneurysms reported in the ISUIA (International Study of Unruptured Intracranial Aneurysms) trial. There was no statistically significant correlation between hemorrhage and any of the following risk factors: hypertension, diabetes, tobacco and alcohol use, polycystic kidney disease, or previous SAH. There was a statistically significant between-groups difference with respect to patient age, with the mean patient age being significantly older in the SAH aneurysm group than in the non-SAH group (p = 0.047). This is likely reflective of longer follow-up and discovery time, as the mean length of time between initial treatment and discovery of the de novo aneurysm was longer in the SAH group (p = 0.011).
Conclusions. While rare, de novo aneurysms may have a risk for SAH that is comparatively higher than the risk associated with similarly sized, small, initially discovered unruptured saccular aneurysms. The authors therefore recommend longterm follow-up for all patients with aneurysms, and they consider a more aggressive treatment strategy for de novo aneurysms than for incidentally discovered initial aneurysms.
Neurosurgery 72:65–69, 2013
Microsurgical clip obliteration remains a time-honored and viable option for the treatment of select aneurysms with very low rates of recurrence.
OBJECTIVE: We studied previously clipped aneurysms that were found to have recurrences to better understand the patterns and configurations of these rare entities.
METHODS: A retrospective review was performed of 2 prospectively maintained databases of aneurysm treatments from 2 institutions spanning 14 years to identify patients with recurrence of previously clipped intracranial aneurysms.
RESULTS: Twenty-six aneurysm recurrences were identified. Three types of recurrence were identified: type I, proximal to the clip tines; type II, distal; and type III, lateral. The most common type of recurrence was that arising distal to the clip tines (46.1%), and the least frequently encountered recurrence was that arising proximal to the tines (19.2%). Laterally located recurrences were found in 34.6% of cases.
CONCLUSION: We describe 3 different patterns of aneurysm recurrence with respect to clip application: those occurring proximal, distal, or lateral to the clip tines.
Neurosurgery 71:1162–1169, 2012
In an era of indocyanine angiography, the routine use of intraoperative angiography (IOA) in the surgical treatment of aneurysms and vascular malformations is controversial.
OBJECTIVE: To retrospectively assess the safety and efficacy of IOA and to determine predictors of surgical revision.
METHODS: Between 2003 and 2011, IOA was performed during surgical treatment of 976 aneurysms, 101 arteriovenous malformations (AVMs), and 16 arteriovenous fistulas.
RESULTS: In 80 of 976 aneurysms (8.2%), IOA prompted clip repositioning. The reason for readjustment was residual aneurysm in 54.7%, parent vessel occlusion in 42.9%, and both in 2.4% of cases. In multivariate analysis, increasing aneurysm size (P,.001), ruptured aneurysm (P,.001), and increasing number of vessels injected (P,.001) were strong predictors of clip readjustment. There was a strong trend for posterior circulation aneurysm location to predict clip repositioning (P = .06). IOA revealed residual nidus/ fistula requiring further intervention in 9 of 101 AVMs (8.9%) and 3 of 16 arteriovenous fistulas (18.8%). Of 9 AVMs requiring a surgical revision, 2 (22.2%) were Spetzler-Martin grade II, 5 (55.6%) were grade III, and 2 (22.2%) were grade IV. Mean Spetzler-Martin grade was 3.0 in AVMs requiring surgical revision compared with 2.3 in those not requiring revision (P = .05). IOA-related complications were all transient or minor and occurred in 0.99% of patients; none resulted in permanent morbidity.
CONCLUSION: IOA remains a valuable tool in the surgical treatment of brain vascular abnormalities, guiding surgical re-exploration in >8% of cases. Easy access to an angiographer and routine use of IOA are important factors contributing to procedural safety and efficacy.
J Neurosurg 117:913–919, 2012
Management of unruptured intracranial aneurysms remains controversial in neurosurgery. The contribution of morphological parameters has not been included in the treatment paradigm in a systematic manner or for any particular aneurysm location. The authors present a large sample of middle cerebral artery (MCA) aneurysms that were assessed using morphological variables to determine the parameters associated with aneurysm rupture.
Methods. Preoperative CT angiography (CTA) studies were evaluated using Slicer software to generate 3D models of the aneurysms and their surrounding vascular architecture. Morphological parameters examined in each model included 5 variables already defined in the literature (aneurysm size, aspect ratio, aneurysm angle, vessel angle, and size ratio) and 3 novel variables (flow angle, distance to the genu, and parent-daughter angle). Univariate and multivariate statistical analyses were performed to determine statistical significance.
Results. Between 2005 and 2008, 132 MCA aneurysms were treated at a single institution, and CTA studies of 79 aneurysms (40 ruptured and 39 unruptured) were analyzed. Fifty-three aneurysms were excluded because of reoperation (4), associated AVM (2), or lack of preoperative CTA studies (47). Ruptured aneurysms were associated with larger size, greater aspect ratio, larger aneurysm and flow angles, and smaller parent-daughter angle. Multivariate logistic regression revealed that aspect ratio, flow angle, and parent-daughter angle were the strongest factors associated with ruptured aneurysms.
Conclusions. Aspect ratio, flow angle, and parent-daughter angle are more strongly associated with ruptured MCA aneurysms than size. The association of parameters independent of aneurysm morphology with ruptured aneurysms suggests that these parameters may be associated with an increased risk of aneurysm rupture. These factors are readily applied in clinical practice and should be considered in addition to aneurysm size when assessing the risk of aneurysm rupture specific to the MCA location.
Neurosurg Rev (2012) 35:497–504
Aneurysms located at the distal portion of the anterior inferior cerebellar artery (AICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of nine distal AICA aneurysms in nine patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals.
Our series includes seven women and two men. Of their nine aneurysms, eight were ruptured and one was unruptured; six were saccular and three were dissecting aneurysms. The most prevalent location was the meatal loop (n=5) followed by the postmeatal (n=3) and premeatal segment (n=1) of the AICA, suggesting hemodynamic stress as an etiology of these distal AICA aneurysms. Of the nine patients, five presented with angiographic features suggestive of increased hemodynamic stress to the AICA and the common trunk of the posterior inferior cerebellar artery, with vertebral artery stenosis, marked laterality, and a primitive hypoglossal artery.
We addressed eight aneurysms (eight patients) surgically; one aneurysm in one patient disappeared in the course of 3 months without surgical treatment. Of the eight surgically treated aneurysms, seven were ruptured and one was unruptured, five were clipped via lateral suboccipital craniotomy, two were trapped via lateral suboccipital craniotomy, and one was embolized. Good outcomes were obtained in six of the eight patients who underwent operation (75 %).
We consider increased hemodynamic stress attributable to anatomic variations in the AICA and related posterior circulation to be the predominant contributor to the development of distal AICA aneurysms. Direct clipping and trapping yielded favorable outcomes in our series.
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.
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.
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.
J Neurosurg 116:764–772, 2012. http://thejns.org/doi/abs/10.3171/2011.12.JNS111256
The aim of this study was to describe the surgical anatomy of the mediobasal aspect of the temporal lobe and the supracerebellar transtentorial (SCTT) approach performed not with an opening, but with the resection of the tentorium, as an alternative route for the neurosurgical management of vascular and tumoral lesions arising from this region.
Methods. Cadaveric specimens were used to illustrate the surgical anatomy of the mediobasal region of the temporal lobe. Demographic aspects, characteristics of lesions, clinical presentation, surgical results, follow-up findings, and outcomes were retrospectively reviewed for patients referred to receive the SCTT approach with tentorial resection.
Results. Ten patients (83%) were female and 2 (17%) were male. Their ages ranged from 6 to 59 years (mean 34.5 ± 15.8 years). All lesions (3 posterior cerebral artery aneurysms, 3 arteriovenous malformations, 3 cavernous malformations, and 3 tumors) were completely excluded or resected. After a mean follow-up period of 143 months (range 10–240 months), the mean postoperative Glasgow Outcome Scale score was 4.9.
Conclusions. Knowledge of the surgical anatomy provides improvement for microsurgical approaches. The evolution from a small opening to a resection of the tentorium absolutely changed the exposure of the mediobasal aspect of the temporal lobe. The SCTT approach with tentorial resection is an excellent alternative route to the posterior part of mediobasal aspect of the temporal lobe, and it was enough to achieve the best neurosurgical management of tumoral and vascular lesions located in this area.
Neurosurgery 70:49–55, 2012 DOI: 10.1227/NEU.0b013e31822cb979
The excimer laser–assisted nonocclusive anastomosis (ELANA) technique enables large-caliber bypass revascularization without temporary occlusion of the parent artery.
OBJECTIVE: To present the surgical experience of 2 bypass centers using ELANA in the treatment of complex intracranial lesions.
METHODS: Between July 2002 and December 2007, 64 consecutive patients (37 in Germany and 27 in Finland) were selected for high-flow bypass surgery with ELANA. Modified Rankin Scale, a bypass success rate, and the success rate of the laser arteriotomy were assessed.
RESULTS: In 66 surgeries for 64 intent-to-treat patients, 58 ELANA procedures were completed successfully. A favorable outcome (postoperative modified Rankin Scale score less than or equal to preoperative modified Rankin Scale) at 3 months was achieved in 43 of 56 patients (77%) with anterior circulation lesions (37 of the 43 patients had aneurysms, 4 had ischemia, and 2 received a bypass before tumor removal) and only in 2 of 8 patients (25%) with posterior circulation aneurysms. Perioperative (, 7 days) mortality for anterior and posterior circulation aneurysms was 6% and 50%, respectively. At the 3-month follow-up, 12% and 63% of patients with anterior and posterior circulation aneurysms, respectively, were dead. The success rate of the laser arteriotomy was 70%. Another 14% were retrieved manually after a nearly complete laser arteriotomy.
CONCLUSION: The ELANA procedure requires a meticulous and careful operative technique. Morbidity and especially mortality rates, usually unrelated to ELANA, are comparable to those of contemporary series of conventional high-flow revascularization operations. This underscores the overall complexity of treating neurovascular pathologies by high-flow bypasses.
Journal of Neurosurgery Oct 2011 / Vol. 115 / No. 4 / Pages 700-706
For oculomotor nerve palsy (ONP) induced by unruptured posterior communicating artery (PCoA) aneurysms, the authors performed surgical clipping via a superciliary keyhole approach as an optimal treatment modality with high efficiency and low invasiveness. In this study, they then evaluated the technical feasibility, safety, clinical outcomes, including recovery from ONP as well as cosmetic results, and durability of the procedure.
METHODS Thirteen patients presenting with complete (7 patients) or incomplete (6 patients) ONP underwent surgery via a superciliary approach. The operative video record was used to evaluate the technical feasibility, neurological examinations and CT were performed to analyze the safety of the treatment, and neuroophthalmological examinations and 3D CT angiography were undertaken to determine the effectiveness and durability of the treatment.
RESULTS In all cases, the aneurysms were successfully clipped using a 3.5-cm eyebrow incision and supraorbital minicraniotomy. The mean operative time was 108 ± 24 minutes. Twelve (92.3%) of the 13 patients showed complete resolution of the ONP. All 6 patients (100%) with incomplete ONP recovered completely within 1–2 months after surgery, whereas 6 (85.7%) of the 7 patients with complete ONP recovered completely within 1–6 months after surgery. Cosmetic results for the operative wounds were excellent without frontalis palsy. The durability of the treatment was ascertained based on 3D CT angiograms obtained 1 year after surgery.
CONCLUSIONS Surgical clipping via a superciliary keyhole approach can be an optimal treatment modality for PCoA aneurysms inducing ONP because it is effective, safe, and durable.
Neurosurgery 69:344–348, 2011 DOI: 10.1227/NEU.0b013e31821819a0
Recent advances in skull base and microsurgical techniques minimize the need for brain retraction.
OBJECTIVE: We studied the impact of such techniques in 36 patients (51 aneurysms) using magnetic resonance imaging (MRI).
METHODS: Preoperative and 24 hours postoperative MR imaging was performed in patients undergoing microsurgical clipping of intracranial aneurysms. Images were evaluated for parenchymal signal changes. During surgery, use and time of brain retraction were recorded. The degree of cortical injury was quantified using a 0 to 3 scale (grade 0 = normal surface; 1 = pial/arachnoidal damage; 2 = gray matter injury; 3 = contusion/necrosis).
RESULTS: Brain retraction by use of a brain spatula was used in all patients. Retraction times ranged from 14 to 290 minutes (mean, 84.1). Cortical surface changes were grade 0 in 86% and grade 1 in 14%; none showed grade 2 or 3 changes. In the postoperative MRI, 4 patients presented with parenchymal alterations, 4 with edema (11.1%), and 1 patient had additional contusion (2.8%). All lesions were confined to the temporal pole. The grade of cortical surface changes was not related to lesions found on MR imaging. No patients showed retraction-related neurological deficits.
CONCLUSION: The incidence of evident mechanical parenchymal injury (infarction or contusion) is very low when appropriate microsurgical and skull base techniques are used. Minor pia-arachnoid injury should nevertheless continue to be attended through future advances.
Neurosurgery 68[ONS Suppl 2]:ons294–ons299, 2011 DOI: 10.1227/NEU.0b013e31821343c6
Intraoperative rupture of an intracranial aneurysm is a potentially devastating but avoidable and manageable complication of aneurysm surgery.
OBJECTIVE: To describe a surgical technique that the authors have used successfully to repair a tear at the neck of an intracranial aneurysm, as well as alternative options for managing this intraoperative complication.
METHODS: The tear on the neck of the aneurysm is covered with a small piece of free cotton and held in place with a suction device to clear the field of blood. The cotton is then clipped onto the tear with an aneurysm clip, using the cotton as a bolster to obliterate the tear. The cotton increases the surface area, allowing the clip to be placed more distally on the neck to preserve patency of the parent artery. Case examples are used to illustrate the technique.
RESULTS: Both authors independently have used this technique on several occasions to successfully repair tears at the neck of an aneurysm.
CONCLUSION: Intraoperative rupture of an intracranial aneurysm is a potentially devastating complication, particularly if a tear occurs at the neck. This simple yet effective method has been very useful in repairing a partial avulsion or tear of the neck of an aneurysm.
Neurosurgery 68[ONS Suppl 2]:ons310–ons316, 2011 DOI: 10.1227/NEU.0b013e3182117063
The anterior communicating artery (AcoA) aneurysm is one of the most challenging aneurysms. As endovascular techniques evolve, a remaining challenge is the reduction of complications related to the surgical approach. Although the endonasal approach is widely used for pituitary adenomas and is increasingly popular for suprasellar tumors, only 2 aneurysm cases have been reported.
OBJECTIVE: To the best of our knowledge, we are reporting the first case of successful endoscopic endonasal clipping of an unruptured ACoA aneurysm.
METHODS: An ACoA aneurysm was discovered in a 55-year-old man before he was to undergo an endoscopic biopsy of an orbital lesion. Because of the operative corridor formed during this first operation and ideal conformation of the aneurysm for this line of sight, we formulated an endoscopic route for this ACoA aneurysm.
RESULTS: An endoscopic endonasal transplanum-transtuberculum approach was performed. Proximal and distal control was obtained, and the AcoA aneurysm was successfully clipped. The postoperative course was uneventful with a rapid recovery.
CONCLUSION: On the road of innovation in the treatment of intracranial aneurysms, the endoscopic approach provided another option whose value must be weighed in terms not only of feasibility but in the patient’s best interest. We caution extreme prudence if considering this procedure as an alternative to well-established techniques. Yet its upward route offers limited retraction for deep-seated lesions. Rapid progress of endoscopic techniques may prove promising for well-selected cases of ACoA aneurysms.
J Neurosurg 114:1088–1094, 2011. DOI: 10.3171/2010.8.JNS10759
Surgical routes to posterior inferior cerebellar artery (PICA) aneurysms are opened between the vagus (cranial nerve [CN] X), accessory (CN XI), and hypoglossal (CN XII) nerves for safe clipping, but these routes have not been systematically defined. The authors describe 3 anatomical triangles and their relationships with PICA aneurysms, routes for surgical clipping, outcomes, and angiographically demonstrated anatomy.
Methods. The vagoaccesory triangle is defined by CN X superiorly, CN XI laterally, and the medulla medially. It is divided by CN XII into the suprahypoglossal triangle (above CN XII) and the infrahypoglossal triangle (below CN XII). From a consecutive surgical series of 71 PICA aneurysms in 70 patients, 51 aneurysms were analyzed using intraoperative photographs.
Results. Forty-three PICA aneurysms were located inside the vagoaccessory triangle and 8 were outside. Of the aneurysms inside the vagoaccessory triangle, 22 (51%) were exposed through the suprahypoglossal triangle and 19 (44%) through the infrahypoglossal triangle; 2 were between triangles. The lesions were evenly distributed between the anterior medullary (16 aneurysms), lateral medullary (19 aneurysms), and tonsillomedullary zones (16 aneurysms). Neurological and CN morbidity linked to aneurysms in the suprahypoglossal triangle was similar to that associated with aneurysms in the infrahypoglossal triangle, but no morbidity was associated with PICA aneurysms outside the vagoaccessory triangle. A distal PICA origin on angiography localized the aneurysm to the suprahypoglossal triangle in 71% of patients, and distal PICA aneurysms were localized to the infrahypoglossal triangle or outside the vagoaccessory triangle in 78% of patients.
Conclusions. The anatomical triangles and zones clarify the borders of operative corridors to PICA aneurysms and define the depth of dissection through the CNs. Deep dissection to aneurysms in the anterior medullary zone traverses CNs X, XI, and XII, whereas shallow dissection to aneurysms in the lateral medullary zone traverses CNs X and XI. Posterior inferior cerebellar artery aneurysms outside the vagoaccessory triangle are frequently distal and superficial to the lower CNs, and associated surgical morbidity is minimal. Angiography may preoperatively localize a PICA aneurysm’s triangular anatomy based on the distal PICA origin or distal aneurysm location.
Neurosurgery 68:310–318, 2011 DOI: 10.1227/NEU.0b013e3182010ed0
Slow or stagnant flow is a hemodynamic feature that has been linked to the risk of aneurysm rupture.
OBJECTIVE: To assess the potential value of the ratio of the volume of an aneurysm to the area of its ostium (VOR) as an indicator of intra-aneurysmal slow flow and, thus, in turn, the risk of rupture.
METHODS: Using a sample defined from internal databases, a retrospective analysis of aneurysm size, aspect ratio (AR), and VOR was performed on a series of 155 consecutive aneurysms having undergone 3-dimensional digital subtraction angiography as a part of their evaluation. Measurements were obtained from 3-dimensional digital subtraction angiography studies using commercial software. Aneurysm size, AR, and VOR were correlated with rupture status (ruptured or unruptured). A multiple logistic regression model that best correlated with rupture status was generated to evaluate which of these parameters was the most useful to discriminate rupture status. This model was validated using an independent database of 62 consecutive aneurysms acquired outside the retrospective study interval.
RESULTS: VOR showed better discrimination for rupture status than did size and AR. The best logistic regression model, which included VOR rather than size or AR, determined rupture status correctly in 80.6% of subjects. The reproducibility calculating AR and VOR was excellent.
CONCLUSION: Determination of VOR was easily done and reproducible using widely available commercial equipment. It may be a more robust parameter to discriminate rupture status than AR.
Neurosurgery 67[ONS Suppl 2]:ons333–ons341, 2010 DOI: 10.1227/NEU.0b013e3181f7451b
Large and giant lesions often have thicker, atheromatous walls as well as intra-aneurysmal thrombus that combine to prevent traditional clips from closing properly in some cases.
OBJECTIVE: To report the development and use of a novel clip design specifically tailored to treat atheromatous, thrombotic, or previously coiled aneurysms.
METHODS: We retrospectively reviewed the records of 6 patients with complex aneurysms not amenable to simple neck clipping and not considered appropriate for endovascular therapy who were treated using a novel ‘‘compression’’ clip design. We describe the development and use of a novel aneurysm clip design with blades that are not opposed at rest to allow direct clipping of atheromatous, thrombotic, and previously coiled aneurysms.
RESULTS: Four patients had recurrent, previously coiled aneurysms; one of these also had a large thrombotic component. Two patients had complex lesions with heavy atheroma involving a portion of their aneurysms. There were no complications related to the use of the clip, and all patients did well without neurological complications. In every case, the clip allowed straightforward obliteration of the aneurysm without the need for temporary vascular occlusion, aneurysmorrhaphy, or removal of an intra-aneurysmal coil mass. All patients underwent intraoperative angiography to confirm obliteration of the aneurysm with preservation of the normal vasculature.
CONCLUSION: Atheromatous, thrombotic, and previously coiled aneurysms may not be treatable with simple neck clipping and may not be curable with endovascular therapy. For such cases, we designed a novel ‘‘compression’’ clip that has been used safely and successfully in our experience with good short-term follow-up.