Minimally Invasive Approaches Suitable For Ruptured Aneurysms Of Cerebral Anterior Circulation: A Prospective Study At A Single Institute – Nguyen Huu Hung

Journal of military pharmaco-medicine n o 4-2019 139 MINIMALLY INVASIVE APPROACHES SUITABLE FOR RUPTURED ANEURYSMS OF CEREBRAL ANTERIOR CIRCULATION: A PROSPECTIVE STUDY AT A SINGLE INSTITUTE Nguyen Huu Hung1; Nguyen The Hao2 Nguyen Tho Lo3; Vu Van Hoe3; Nguyen Van Hung3 SUMMARY Objectives: A prospective study was underway to evaluate the outcome of minimally invasive approaches for ruptured anterior circulation aneurysms. Subjects and methods: From September 2015 to September 2018, 72 patients with ruptured cerebral anterior circulation aneurysms: aneurysms anterior communicating artery and aneurysms middle cerebral artery, aneurysms posterior communicating artery, aneurysms anterior choroidial artery, and aneurysms carotid terminus (bifurcation) were operated by an experienced neurosurgical team through minipterional and supraorbital craniotomies. The clinical data were analyzed. Results: Patients with clinical grade 1 (66.67%), grade 2 (23.61%), grade 3 (9.72%) and subarachnoid hemorrhage grade 1 (8.33%), grade 2 (19.44%), grade 3 (72.22%) were selected for minimally invasive approaches. All aneurysms were small size. The rate of intra-operative rupture was 8.33% and all ruptures were safely controlled. Of all, 67 patients (93.06%) achieved favorable outcomes versus 3 patients (4.17%) with hemiparaplegia and 2 patients (2.78%) with cerebrospinal fluid leakage. Conclusions: Minimally invasive approaches for cerebral anterior circulation aneurysm clipping give good surgical results, high proportion of aneurysmal occlusion, low rate of post-operative complications, which are suitable for ruptured cases with good clinical grade from 1 - 3 and cases of no severe subarachnoid hemorrhage. It should not be indicated for cases with high score of subarachnoid hemorrhage, important vasospasm, cerebral herniation. * Keywords: Anterior circulation aneurysms; Subarachnoid hemorrhage; Minimally invasive approaches. INTRODUCTION The concept of the minimally invasive keyhole approaches in neurosurgery have been increasingly applied in the past 25 years. For anterior circulation aneurysms, the most commonly-used keyhole approaches are minipterional and supraorbital keyhole craniotomies [1, 2, 4, 5, 9], which are different from standard pterional approach [3], because of smaller craniotomies, shorter operation time and excellent cosmetic results. Regarding ruptured aneurysms, however, an unexpected intra-operative rupture or cerebral swelling might be difficult to control, since the dissection of basal cisterns and extent of decompression are limited with minimally invasive approaches. 1. 17 Military Hospital 2. Bachmai Hospital 3. 103 Military Hospital Corresponding author: Nguyen Huu Hung (hungvanc17@gmail.com) Date received: 22/01/2019 Date accepted: 25/04/2019 Journal of military pharmaco-medicine n o 4-2019 140 This study was conducted prospectively aiming: Analyzing the outcomes in patients receiving minimally invasive approaches for ruptured cerebral anterior circulation aneurysms: aneurysms anterior communicating artery and aneurysms middle cerebral artery, aneurysms posterior communicating artery, aneurysms anterior choroidial artery, and aneurysms carotid terminus (bifurcation). SUBJECTS AND METHODS 1. Subjects. From September 2015 to September 2018, a total of 72 patients under 80 years old who had ruptured aneurysms of cerebral anterior circulation with World Federal of Neurological Surgeons (WFNS) score 1 - 3, Fisher grade 1 - 3, and good general health were operated through minimally invasive approaches in Department of Neurosurgery, Bachmai Hospital, Hanoi. The ruptured aneurysms were affirmed by CT angiogram (CTA) or DSA. We excluded the patients with WNFS score 4 - 5, unruptured aneurysms, giant aneurysms and paraclinoid aneurysms. 2. Methods. Mini-pterional and supraorbital keyhole craniotomies were selected case-by-case, based on the preoperative CT scan and CTA evaluations by our experienced neurosurgical team. In particular: - Mini-pterional craniotomies: Using for aneurysms of the proximal segment or bifurcation of middle cerebral artery. - Supraorbital keyhole craniotomies: Using for other aneurysms: such as aneurysms anterior communicating artery, aneurysms posterior communicating artery, aneurysms anterior choroidial artery, and aneurysms carotid terminus (bifurcation). The clinical and imaging findings include: age, sex, clinical signs, Fischer grade, aneurysm locations, intraoperative advantages and disvantages, post-operative complications, surgical results were evaluated after 03 months since hospital discharge according to Modified Rankin Scale (mRS): good (score 0 - 2), average (score 3 - 4), bad (score 4 - 5). CTA or DSA were followed up to evaluate the residual aneurysms and arterial infarction. * Supraorbital keyhole approach: The skin incision was made laterally two thirds of the eyebrow. The medial border of the incision was the supraorbital notch. A small craniotomy no larger than 30 mm was formed. A dural flap was created in a curvilinear fashion. With gentle retraction of the orbital gyri, the prechiasmatic, internal carotid, and dissection of the Sylvian fissure was performed directly with microsurgical instruments, to expose the ICA, A1, PcomA, ipsilateral optic nerve, and optic chiasm. The aneurysm neck was visualized and clipped. Hemostasis was verified, and the dura was closed and made watertight. The bone flap was replaced and fixed with a titanium plate. The skin and muscles were closed in layers. Journal of military pharmaco-medicine n o 4-2019 141 Image 1: Patient was operated by supraorbital keyhole approach. * Mini-pterional keyhole approach: The skin incision was started 1.0 cm above the base of the zygomatic arch, extended posteriorly parallel to the hairline border, and then gradually curved superiorly toward a point crossing the ipsilateral midpupillary line. Dissection of the temporalis muscle and fascia and protection of the frontalis branch of the facial nerve were performed as they were in the classical pterional approach. The muscular flap was retracted posteriorly and caudally to expose the Sylvian point. A burr hole was placed just above the front-ozygomatic suture. A small craniotomy no larger than 30 mm was formed. The dural sac was opened in a semilunar fashion and the Sylvian fissure was visualized at the center of the surgical field. Dissection of the Sylvian fissure was performed directly with microsurgical instruments to expose the M2, M1, ICA, A1, PcomA, ipsilateral optic nerve and optic chiasm. The aneurysm neck was visualized and clipped. Hemostasis was verified, and the dura was closed and made watertight. The bone flap was replaced and fixed with a titanium plate. The skin and muscles were closed in layers. Image 2: Patient was operated by minipterional keyhole approach. Journal of military pharmaco-medicine n o 4-2019 142 RESULTS There were 37 males (51.39%) and 35 females (48.61%). The average age was 55.98 ± 8.96 years with a range from 35 to 77 years. There were 55.56% of patients earlier operated on the 4 first days, 33.33% of patients underwent the surgery from day 4th to 10th after ruptured aneurysm. The mean size of aneurysm in our series was 4.91 ± 2.27 mm x 4.45 ± 1.31 mm. The average size of the incisions was 5.30 ± 0.46 cm. The average time of operations was 92.01 ± 23.46 minutes. 47.22% of patients were operated by supraorbital keyhole approach and 52.78% of those were operated by minipterional keyhole approach. 66.67% of patients who had clinical grade 1, 23.61% in grade 2 and 9.72% in grade 3. 8.33% of patients had subarachnoid hemorrhage in grade 1, 19.44% of whom in grade 2 and 72.22% in grade 3. 100% of patients were examined by CTA scan before operation: the location of aneurysm including aneurysms anterior communicating artery (48.61%) and aneurysms middle cerebral artery (16.67%), aneurysms posterior communicating artery (29.17%), aneurysms anterior choroidial artery (4.17%), and aneurysms carotid terminus (bifurcation) (1.39%). Table 1: Characteristics and general outcomes of ruptured anterior circulation aneurysms. Patients Percentage (%) Gender Female 35 48.61 Male 37 51.39 Average age 55.98 ± 8.96 Clinical grade (WFNS) Grade 1 48 66.67 Grade 2 17 23.61 Grade 3 7 9.72 Subarachnoid hemorrhage Grade 1 6 8.33 Grade 2 14 19.44 Grade 3 52 72.22 Surgical timing 1 - 4 days 40 55.56 5 - 10 days 24 33.33 > 10 days 8 11.11 Approaches Supraorbital 34 47.22 Minipterional 38 52.78 Journal of military pharmaco-medicine n o 4-2019 143 Mean size of aneurysm (mm) 4.91 ± 2.27 x 3.45 ± 1.31 Location of aneurysm Aneurysms anterior communicating artery (AcomA) 35 48.61 Aneurysms middle cerebral artery (MCA) 12 16.67 Aneurysms posterior communicating artery (PcomA) 21 29.17 Aneurysms anterior choroidial artery (AChoA) 3 4.17 Aneurysms carotid terminus 1 1.39 Average size of the incision (cm) 5.30 ± 0.46 Rate of intraoperative aneurysmal rupture 6 8.33 Average time of operation (minute) 92.01 ± 23.46 Average post-operative intensive care unit staying (hour) 20.34 ± 9.84 Average hospital stay postoperative (day) 9.20 ± 5.15 Postoperative complications Cerebrospinal fluid leakage 2 2.77 Paralysis 3 4.17 Postoperative CTA results Residual aneurysm 2 2.78 Arterial infarction 1 1.39 Cerebral vasospasm 1 1.39 Complete occlusion of aneurysms 70 97.22 Good clinical outcome (mRankin 0 - 2) 67 93.06 At early stage, we had ever faced with transient swollen brain, however, we were finally able to get access to the aneurysm after releasing the cerebrospinal fluid gradually. In 6 cases (8.33%), we had to face with intraoperative rebleeding during peri-aneurysmal dissection. With temporary occlusion of parent artery and prompt clipping of aneurysm neck, none of cases died or suffered from severe morbidity. All patients enjoyed good cosmetic results. Sixty seven patients (93.06%) achieved favorable outcomes (mRankin 0 - 2), with complete occlusion of aneurysms in 70 cases (97.22%). There were 3 patients with hemiparaplegia and 2 patients with cerebrospinal fluid leakage in our series. Journal of military pharmaco-medicine n o 4-2019 144 DISCUSSION 1. Surgical indications. We chose minimal invasive approaches for the patients with clinical grades from 1 - 3 (World Federal of Neurological Surgeon Committee score) and Fisher grades 1 - 3. Yamahata H et al concluded that the minimal invasive approach should not be indicated for the severe cases with Hunt-Hess grade more than 4 and Fisher 4 because cerebral edema and intra- operative rupture will be big challenges for surgeon while using minimally invasive approach [10]. Patient selection plays a very important role, according to the authors: Pham Quynh Trang, Fischer G et al, Nguyen The Hao et al, who created a HBM score in which total clinical score and Fisher less than 5, the minimal invasive approaches were indicated in these cases [1, 2, 5]. Minimally invasive approaches selection also depends on aneurysmal locations and size. We excluded the paraclinoidal aneurysms because the anterior clinoidectomy requires bigger space that minimal invasive approaches cannot provide. The mean size of aneurysm in our study was 4.91 ± 2.27 mm x 3.45 ± 1.31 mm. We did not use minimally invasive approaches for big and giant aneurysms because they usually have wide neck, multilobe so it is difficult for surgeon during dissection and clipping when manipulating in a narrow space. In the literature, the previous authors agreed that keyhole approaches should only be used for small aneurysms. 2. Surgical timing. Surgical time depends on patients‟ admission time but we operated as soon as possible to avoid re-bleeding complication and vasospasm treatment could be done soon after surgery. In our series, 55.56% of patients were operated on the 4 first days, 33.33% of the patients from day 4 to day 10. After Lan Q et al, minimally invasive approaches can be realized in every moment when there is no intracranial high pressure and no evident of severe vasospasm [7]. Intracranial high pressure can be handled by medical treatment with manitol, furocemid or cerebrospinal fluid suction from cranial base or ventricular drainage. 27.78% of our patients had cerebral edema, in which we had to open the cranial base subarachnoid space (76.39%) or ventricular drain (1 case). In Lan Q‟s series, there were 3 patients with Hunt Hess 4 in which minimally invasive approaches were indicated and these patients underwent the second decompressive craniectomy due to post- operative cerebral edema [7]. 3. Surgical results. Application of minimally invasive approaches in aneurysmal clipping was started 25 years ago and in Vietnam in 2012 [1]. In our study, we evaluated the surgical result when the patient was discharged from hospital. The mortality was 0%, 2 patients (2.77%) had cerebrospinal fluid leaks, 3 patients (4.17%) had a hemiparaplegia in which 1 had a anterior choroidal artery infarction complication. In 3 month follow-up, there were 93.6% with mRankin 0 - 2. Michell P Journal of military pharmaco-medicine n o 4-2019 145 et al had a similar result with good mRankin in 85.1% [8]. Ficher G et al reported several deaths but all due to general medical diseases [5]. Follow-up CTA or DSA showed 2 cases of residual aneurysms. Total occlusion was 97.22%, one patient had artery occlusion. Chen L et al reported 92% of total occlusion [4]. Ficher G et al had 2% residual out of 1,297 cases [5]. Nguyen The Hao, Chalouhi N et al, Mitchell P et al had 100% of total occlusion [1, 3, 8]. Mean operation time and post-operative intensive care unit staying 92.01 ± 23.46 minitues and 20.34 ± 9.84 hours. In Chalouhi‟s study, most of patients with minimally invasive approach, post-operative intensive care unit length of stay was less than 24 hours, there was a difference compared to clinical approaches (p = 0.02). Our average post-operative hospitalization was 9.2 ± 5.15 hours, longer than in Mitchell P‟s study with average 5 days [8], Pham Quynh Trang 4.3 days [2]. It was probably due to 5 patients with long hospitalization because of post-operative complications. The other patients had an average of 7 days post-operation. 4. The surgical difficulties. Surgeon‟s manipulations meets more challenges than with classical surgery because of narrow surgical fields, weak alumination and difficult orientation, especially when there were intra-operative rerupture. We had 6 cases (8.33%) of intraoperative aneurysmal rupture in which one case happened in early phase, so that the surgeon had difficulty in clipping parental arteries. The surgeon had to enlarge the craniotomy due to acute brain swelling. In other series, intra-operative rebleeding happened mostly in the first days. Some authors suppose that the temporary clipping should be done intentionally [1, 5, 7]. In recent years, the introduction of endovascular treatment for aneurysms seems to be highly promising, and the ISAT trial found significantly better outcomes (survival free of disability) with coiling than with clipping [6]. The excellent outcome (93.06%) in our series with minimally invasive microsurgery proved to be comparable to that with endovascular approach; furthermore, the former leads to a cure while the latter packs the aneurysm only. In spite of the questions whether minimally invasive approaches are safe enough, our results suggested that good surgical outcomes depend not only on the selected approach, but the individual patient specifically selected, surgeon‟s concept and experience as well. In our experience, surgeon may decide between minimally invasive and standard approaches according to the clinical grade, subarachnoid hemorrhage in grade, the location of aneurysm, the size and complexity of aneurysm, as well as the preference and experience of the neurosurgical team. CONCLUSIONS Keyhole approaches for cerebral anterior circulation aneurysm clipping give good surgical results, high proportion of aneurysmal occlusion, low rate of post- operative complications, which are suitable Journal of military pharmaco-medicine n o 4-2019 146 for ruptured cases with good clinical grade from 1 - 3 and no severe subarachnoid hemorrhage. It should not be indicated for cases with high score of subarachnoid hemorrhage, important vasospasm, cerebral herniation. REFERENCES 1. Nguyễn Thế Hào, Phạm Quỳnh Trang, Trần Trung Kiên. Nghiên cứu hiệu quả và tính oan toàn của phẫu thuật ít xâm lấn trong điều trị túi phình động mạch não vỡ. Y học Thành Phố Hồ Chí Minh. 2017, tập 21, phụ bản số 6, tr.137-141. 2. Phạm Quỳnh Trang. Kết quả điều trị vi phẫu thuật túi phình động mạch thông trước bằng đường mở sọ lỗ khóa trên ổ mắt. Luận văn Thạc sỹ Y học. Trường Đại học Y Hà Nội. 2014. 3. Chalouhi N, Jabbour P, Ibrahim I et al. Surgical treatment of ruptured anterior circulation aneurysms: Comparison of pterional and supraorbital keyhole approaches. 2013. 4. Chen L, Tian X, Zhang J. Is eyebrow approach suitable for ruptured anterior circulation aneurysms on early stage: A prospective study at a single institute. Acta Neurochirurgica. 2009, 151, pp.781-784. 5. Fischer G, Stadie A, Reisch R et al. The keyhole concept in aneurysm surgery: Results of the past 20 years. Operative Neurosurgery 1. 2011, 68, pp.45-51. 6. ISAT Collaborative Group. International subarachnoid aneurysm trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2,143 patients with ruptured intracranial aneurysms: A randomised comparison of effects on survival, dependency, seizures, rebleeding, subgroups, and aneurysm occlusion. Lancet. 2005, 366, pp.809-817. 7. Lan Q, Gong Z, Kang D et al. Microsurgical experience with keyhole operations on intracranial aneurysms. Surg Neurol. 2006, 66 (S1), pp.2-9. 8. Mitchell P, Vindlacheruvu R, Mahmood K. Supraorbital eyebrow minicraniotomy for anterior circulation aneurysms. Surgical Neurology. 2005, 63, pp.47-51. 9. Wong J. H.Y, Tymianski R, Radovanovic I et al. Minimally invasive microsurgery for cerebral aneurysms. Stroke. 2015, p.46. 10. Yamahata H, Tokimura H, Tajitsu K et al. Efficacy and safety of the pterional keyhole approach for the treatment of anterior circulation aneurysms. Neurosurg Rev. 2014, 37, pp.629-636.