Improvement after treatment of hydrocephalus in aneurysmal subarachnoid haemorrhage: implications for grading and prognosis

Summary Two patients with aneurysmal subarachnoid haemorrhage and hydrocephalus are presented. On admission they scored E1M4V1 and E1M3Vtube on the Glasgow Coma Scale. The first patient recovered to E3M5Vtube after treatment of hydrocpehalus by extraventricular drainage. The second recovered to E2M5Vtube and later E4M6V4 after treatment of hydrocephalus with lumbar drainage. Based on the literature it is argued that these cases are no exception as to the improvement after treatment of hydrocephalus. The prognosis of patients with hydrocephalus after a subarachnoid haemorrhage, improves in parallel with the Glasgow Coma Scale after treatment of hydrocephalus. Therefore decision making on whether or not to treat a patient with a subarachnoid haemorrhage should be postponed until after treatment of hydrocephalus, if present.     

Preoperative ventriculostomy and rebleeding after aneurysmal subarachnoid hemorrhage

OBJECT: Despite the widespread use of ventriculostomy in the treatment of acute hydrocephalus after aneurysmal subarachnoid hemorrhage (SAH), there is no consensus regarding the risk of rebleeding associated with ventriculostomy before aneurysm repair. This present study was conducted to assess the risk of rebleeding after preoperative ventriculostomy in patients with aneurysmal SAH. METHODS: The authors reviewed the records of all patients with acute SAH who were treated at a single institution between 1990 and 1997. Thus, the records of 304 consecutive patients in whom an aneurysmal SAH source was documented on angiographic studies and who had presented to the authors' institution within 7 days of ictus were analyzed. Re-bleeding was confirmed by evidence of recurrent hemorrhage on computerized tomography scans in all cases. Forty-five patients underwent ventriculostomy for acute hydrocephalus after aneurysmal SAH at least 24 hours before aneurysm repair. Ventriculostomy was performed within 24 hours of SAH in 38 patients, within 24 to 48 hours in three patients, and more than 48 hours after SAH in four patients. The mean time interval between SAH and surgery in patients who did not undergo ventriculostomy was no different from the mean interval between ventriculostomy and surgery in patients who underwent preoperative ventriculostomy (3.6 compared with 3.8 days, p = 0.81). Fourteen (5.4%) of the 259 patients who did not undergo ventriculostomy suffered preoperative aneurysm rebleeding, whereas two (4.4%) of the 45 patients who underwent preoperative ventriculostomy had aneurysm rebleeding. CONCLUSIONS: No evidence was found that preoperative ventriculostomy performed after aneurysmal SAH is associated with an increased risk of aneurysm rebleeding when early aneurysm surgery is performed.     

Cerebrospinal fluid production in subarachnoid haemorrhage

Eight patients with subarachnoid and/or intraventricular haemorrhage underwent continuous extraventricular drainage and cerebrospinal fluid production was estimated by modified open drainage. The patients were in Hunt & Hess grades 2-5 on admission. Drainage was instituted within 24 h after the last bleeding episode in seven patients and the duration of drainage was 3-37 days. The median amount of CSF that was drained in 24 h was 210 ml. CSF production rate was 0.10-0.55 ml/min (median 0.28 ml/min) and there was a great variation within as well as between patients. Thus there was a trend towards a reduction in CSF production compared to reported normal values for CSF production. Three of six surviving patients required a shunt. The possible role of reduction in CSF production rate in the modification of intracranial hypertension and hydrocephalus after subarachnoid haemorrhage is discussed.     

Effect of recombinant tissue plasminogen activator on clot lysis and ventricular dilatation in the treatment of severe intraventricular haemorrhage

Summary Twelve patients with severe intraventricular haemorrhage (IVH) underwent intraventricular thrombolysis with recombinant tissue plasminogen activator (rtPA). External ventricular drainage was performed in all patients within 24 hours of haemorrhage. Fibrinolytic therapy was started within 24 hours from the onset of symptoms in ten cases, and in two further cases after 48 hours and 5 days, respectively. Two to 5 mg of rtPA were injected via the ventricular catheter into one or both lateral ventricles. The injection was repeated at intervals ranging from 6 to 24 hours until CT scans demonstrated a substantial reduction of intraventricular blood. The total rtPA doses per patient ranged from 3 to 31 mg.CT scans showed a marked reduction of intraventricular blood and normalization of ventricular size within 24 to 48 hours from the beginning of the flbrinolytic therapy. Rapid reduction of elevated intracranial pressure by continuous diversion of cerebrospinal fluid could be achieved in all patients, because the ventricular catheters never became obstructed by clotted blood during the fibrinolytic therapy. During the period of treatment, the level of consciousness, as classified according to the Glasgow Coma Scale, improved from a mean value of 7 to 12. One fatal case of meningitis most probably due to the ventriculostomy was the only complication related to the treatment.This method of treatment might improve the prognosis in patients in whom a large intraventricular haematoma volume, ventricular dilatation, and impaired cerebrospinal fluid circulation are major determinants for the outcome.     

Perimesencephalic and nonperimesencephalic subarachnoid haemorrhages with negative angiograms

SummaryBackground van Gijn and co-workers identified Perimesencephalic haemorrhage (PM) as distinct, benign, non-aneurysmal subarachnoid haemorrhage. However, there is only one retrospective series of this entity outside the Netherlands.Purpose to confirm (or not) the benign nature of perimesencephalic subarachnoid haemorrhage by evaluating its clinical course and long-term follow-up in a consecutive series of patients admitted to a University Hospital.Methods Patients with subarachnoid haemorrhage and negative cerebral angiography admitted between January 1985 and April 1992 were classified according to the distribution of blood on a CT scan performed within 72 hours after onset, in perimesencephalic and non-perimesencephalic haemorrhages. Demographic and clinical data (collected consecutively), complications and long-term follow-up (obtained by chart review and follow-up by mail) were compared in the two groups.Results Seventy one cases, 36 perimesencephalic and 35 nonperimesencephalic were included. Sex and age distribution were similar in the two groups. A normal examination on admission was the rule in the perimesencephalic group. Only one patient with perimesencephalic haemorrhage had a complication — transient neurological signs during angiography — and there were no deaths or morbidity during follow-up. In the non-perimesencephalic group three patients rebleed, four developed hydrocephalus and two had delayed cerebral ischaemia. Mean duration of follow-up was 27,6 months for the perimesencephalic and 30,8 months for the non-perimesencephalic group. After discharge there was a fatal rebleed in the latter group. Fifteen percent of the subjects (11% of the perimesencephalic group and 20% of the non-perimesencephalic group) retired from work during the follow-up period. Headaches and depression were found in similar percentages (22–25%) in both groups.Conclusions This study confirms that perimesencepahlic haemorrhage is a distinct entity within the larger group of subarachnoid haemorrhage with negative angiograms, with a good short term and long-term prognosis, and no need for repeated angiographic investigation.     

Urokinase infusion for severe intraventricular haemorrhage

Summary The purpose of this study was to explore in patients with intraventricular haematomas the effectiveness and complication rate of a treatment protocol including standard ventriculostomy and application of urokinase via the catheter.Our series includes 16 patients with severe CT-diagnosed intraparenchymal and predominantly intraventricular haemorrhages. In all cases, ventricular drainage was performed. Urokinase treatment was started immediately with intraventricular infusions of 10,000 U urokinase in 5 ml sterile physiological saline every 12 hours. Twelve patients had an excellent outcome, three good and one poor. There were no complications related to urokinase therapy. Side efects of the infusion volume were profuse sweating and headache which were present at 10 ml total infusion volume, but disappeared after reduction to 5 ml. A group of five patients with comparable lesions treated only with ventriculostomy served as controls. Two of them had a good outcome, two a poor one and one died. The late results in the urokinase-treated group were also favourable. Only one of the patients developed hydrocephalus and was shunted. In the control group, two patients required shunting for delayed hydrocephalus.We conclude that this protocol for urokinase treatment is safe and effective and can be used in almost all patients with intracerebroventricular haemorrhage.     

Factors affecting outcome after surgery for intracranial aneurysm in Glasgow.

Two-hundred and ninety-five patients with angiographically demonstrated intracranial aneurysms presented to the Institute of Neurological Sciences, Glasgow over a 3-year period (1986-88). We have reviewed this group to assess the effect of changing patterns of management upon outcome. The overall mortality rate was 9.4%, and the surgical mortality rate was 4% in this selected series. Factors significantly associated with a poor outcome were: WFNS grades III-V on admission, presence of a haematoma on the first CT scan, delayed ischaemic deficit, and development of a post-operative haematoma. Seventy-six per cent of the patients who developed a delayed ischaemic deficit (nearly a third of those with recent subarachnoid haemorrhage) made a good recovery, in contrast to previous studies, and over two-thirds of those accepted in grades IV and V (28 patients) made a good recovery after surgery. Active management of patients in grades IV and V, and those with delayed ischaemia, together with prophylactic Nimodipine therapy and selective early surgery, offers the best prospect for further improvement in outcome after aneurysmal subarachnoid haemorrhage.     

动脉瘤性蛛网膜下腔出血后持续腰大池引流的时机对分流依赖性脑积水的影响

目的分析发生动脉瘤性蛛网膜下腔出血后行持续腰大池置管引流术距出血发生间隔的长短对患者发生分流依赖性脑积水的影响。方法回顾性分析2015年9月至2017年9收治的178例动脉瘤性蛛网膜下腔出血患者,依据患者行腰大池置管引流术距出血的时间分为24小时以内(A组56例)、24~72小时(B组79例)、超出72小时(C组43例)三组,分析行腰大池置管引流距出血时间的长短对分流依赖性脑积水发生的影响。结果三组中发生分流依赖性脑积水为:A组5例(8.9%)、B组8例(10.1%)、C组12例(27.9%)。三组间分流依赖性脑积水的发生率有明显差异(P0.05)。结论动脉瘤性蛛网膜下腔出血后许越早行持续腰大池引流于预防分流依赖性脑积水的效果越好。     

Rebleeding from ruptured intracranial aneurysms

Fifty-three of 236 consecutive patients (22.5%) who suffered a proved aneurysmal subarachnoid hemorrhage and who were admitted within 72 hours after subarachnoid hemorrhage to a primary emergency hospital had at least one rebleed within 6 months after the primary bleed. Two patients later had a rebleed within a mean of 3 years follow-up. Rebleeding was recorded if there was a sudden loss of consciousness and a verification by computed tomography, autopsy, lumbar puncture, or angiography. The peak incidence of rebleeding was within the first 24 hours and at the end of the first week after subarachnoid hemorrhage. The rebleed mortality rate was 74%, and only 19% of patients with a rebleed had a good outcome. The grade on admission, age, and sex do not affect the incidence nor the time of rebleeding.     

Management of poor-grade patients with aneurysmal subarachnoid hemorrhage in the acute stage: Importance of close monitoring for neurological grade changes

BACKGROUND: The optimal management of poor-grade patients with aneurysmal subarachnoid hemorrhage (SAH) remains controversial. We evaluated therapeutic outcomes to identify appropriate treatments for SAH patients admitted with a poor grade. METHODS: We retrospectively studied 136 patients admitted within 6 hours after SAH onset with a poor Hunt & Kosnik Grade (IV and V). RESULTS: Of 136 poor-grade patients, 20 with massive intracerebral or subdural hematoma underwent urgent hematoma evacuation and aneurysmal neck clipping. Seven of these achieved a favorable outcome (good recovery or moderate disability). Another 7 patients with prominent hydrocephalus or massive intraventricular hematoma underwent urgent continuous ventricular drainage. Of these, 4 manifested spontaneous grade improvement and underwent neck clipping; the other 3 died resulting from rebleeding. The remaining 109 patients whose poor grade was primarily because of SAH were observed without immediate surgery. In 43 patients of 109, the grade improved within 24 hours after hospitalization and within 38 hours in the other 4 patients. Aneurysmal neck clipping was performed in these 47 patients and a favorable outcome was achieved in 25 patients. The remaining 62 patients did not improve and the outcome was unfavorable. CONCLUSIONS: Poor-grade SAH patients should be treated according to the pathogenesis underlying their poor grade. Close monitoring for a grade change over the first 24 hours after hospitalization is mandatory in patients whose poor grade is primarily because of the SAH and helps to determine the appropriateness of surgery.     

The Risk of Haemorrhage Associated with Early Postoperative Heparin Administration After Intracranial Surgery

Summary  Background. To analyse the rate of postoperative haemorrhage during a 4-year period of early postoperative administration (<24 hours) of fractionated heparin plus compression stockings in a large cohort of patients undergoing intracranial surgery.  Method. A total of 1564 patients who underwent intracranial surgery at our institution were included in our study. 1197 of the 1564 patients (77%) had major intracranial surgery (group 1). Group 2 was made up of 367 patients in whom ventriculoperitoneal shunting or external ventriculostomy was performed (minor intracranial procedures). All patients were investigated retrospectively for the occurrence of major postoperative haemorrhage confirmed by CT scanning and requiring surgical evacuation. The protocol for prophylaxis of thrombo-embolic events included early (<24 hours) postoperative fractionated low-dose heparin (3×5000 IE subcutaneously) until discharge plus intra- and postoperative compression stockings.  Findings. Major postoperative haemorrhages were observed in 31 of the 1564 patients (2.0%). In three patients, the haemorrhage occurred on the day of surgery before the administration of heparin. The haemorrhage rate of patients receiving heparin was 1.8% (28/1564). All haemorrhages occurred in patients undergoing major intracranial procedures (group 1; 31/1197; 2.6%). There was no haemorrhage in minor intracranial procedures (group 2; 0/367; 0%).  Interpretation. Although retrospective, this is to date the largest study supporting the concept of postoperative pharmacological thrombo-embolic propylaxis in patients undergoing intracranial surgery. The question as to whether pharmacological prophylaxis is beneficial for a given patient can only be answered by weighing the risk reduction of thrombo-embolic events against the risk increase of postoperative haemorrhage associated with different surgical procedures and heparin protocols.     

Disturbed cerebrospinal fluid circulation after subarachnoid hemorrhage and acute aneurysm surgery

In 138 patients with ruptured cerebral aneurysms operated on within 48 to 72 hours after subarachnoid hemorrhage, an external ventricular drainage catheter was inserted before craniotomy and was used intermittently during the first week after surgery. In 51 patients, intracranial pressure (ICP) was measured intraoperatively. The majority of patients showed increased ICP intraoperatively irrespective of the preoperative Hunt and Hess grade and the amount of subarachnoid blood accumulation or intraventricular blood clot. Intraoperative drainage of cerebrospinal fluid allowed easy access for aneurysm dissection by making the brain slack in more than 90% of patients. Postoperative ICP measurements revealed that significant brain swelling did not occur in the majority of patients. In 7 patients, persistently elevated ICP (greater than 20 mm Hg) was recorded. Nine patients (8%) developed shunt-dependent hydrocephalus; all of these patients had suffered an intraventricular hemorrhage. Measurements of the volumes of cerebrospinal fluid drained did not allow prediction of shunt-dependent hydrocephalus.     

Endoscopic third ventriculostomy for chronic hydrocephalus after tuberculous meningitis

BACKGROUND: Cerebrospinal fluid diversion procedures are indicated in patients with hydrocephalus after tuberculous meningitis (TBM). We present 2 patients with hydrocephalus after TBM who were successfully treated with endoscopic third ventriculostomy (ETV). METHODS: Two patients had been diagnosed with hydrocephalus after TBM and had undergone ventriculoperitoneal shunt surgery for the same. They presented with multiple episodes of shunt dysfunction. Endoscopic third ventriculostomy was performed (twice for one patient), and the patients were evaluated clinically and radiologically after the procedure. RESULTS: On long-term clinical follow-up (3 and 2 years, respectively), both patients were asymptomatic after the ETV. The first patient was radiologically evaluated 7 months after the procedure and the second patient 2 years after the procedure. The first patient showed a decrease in ventricular size. The second patient did not show any significant change in the ventricular size. CONCLUSION: Endoscopic third ventriculostomy can be considered as a safe and long-lasting solution for hydrocephalus after chronic TBM.     

Dose escalation trial of a novel calcium antagonist,AT877, in patients with aneurysmal subarachnoid haemorrhage

Summary The initial dose-escalating clinical trial of a novel calcium antagonist, AT877, in patients with aneurysmal subarachnoid haemorrhage is reported. AT877 is characterized by its strong spasmolytic activity, its inhibition of intracellular calcium ion activity, and the inhibiton of several protein kinases.A total of 113 patients (Hunt and Hess grades I to IV) who had undergone surgery within 3 days of aneurysmal rupture entered the study. Patients were divided into 5 groups according to the total daily dose of AT877: I: 20 mg; II: 40 mg; III: 60 mg; IV: 90 mg; and V: 120–180 mg. AT877 was given by intravenous infusion over 30 min two or three times a day for 14 days after surgery.Although AT877 did not completely abolish angiographic vasospasm, severe vasospasm was seen less frequently in patients given higher doses. Vasospasm was the cause of a poor clinical outcome (Glasgow outcome scale rating 3 or greater) in 19%, 7%, 9%, 8%, and 6% of the patients in groups I to V, respectively. The results indicated a favourable clinical effect of AT877 at doses above 40 mg per day. Only mild hypotension was seen, even when 60 mg of AT877 was infused over 30 min.AT877 appears to be effective in patients with subarachnoid haemorrhage. Part of its effect may be attributable to protection of the brain from ischaemic insults due to chronic cerebral vasospasm. However, the drug still needs to be evaluated in a placebo-controlled double-blind trial (which is currently being carried out).     

Current pattern of in-hospital aneurysmal rebleeds

Summary The management of aneurysmal subarachnoid haemorrhage has recently changed considerably. Emergency admission to specialized centres and early surgery have become common practice. In addition, the use of nimodipine has gained widespread acceptance. Little data are available concerning the frequency and temporal profile of reruptures under the current policies.The case histories of 387 patients treated for aneurysmal subarachnoid haemorrhage between January 1984 and March 1992 were reviewed with regard to the incidence of in-hospital reruptures. All patients were managed according to the same protocol including a policy of individually timed early surgery and intravenous nimodipine. A total of 44 first in-hospital rebleeds were observed during the waiting period. Two percent of the patients admitted on the day of haemorrhage had a rebleed on the same day after admission to the hospital. No rebleeds were observed on the day after subarachnoid haemorrhage. Rebleed rates on day 2 and 3 were also low with 0.6 and 0.8% of the population with an undipped aneurysm. For the following 10 days, the daily rate of rerupture increased. A further peak was observed during the 4th week. Using life-table methods, the cumulative rate of rebleeds was calculated as 23% within 2 weeks and 42% within 4 weeks. Although patients suffering rebleeds differed in several respects from patients without rebleeds, most of the differences could be identified to be a consequence of a selection bias resulting in a longer period of exposure to the risk of rerupture for certain subgroups. Only patients suffering a loss of consciousness after the initial subarachnoid haemorrhage were definitively exposed to a higher daily risk of rerupture.Comparison with other series suggests that nimodipine treatment may add to the protective effect of bedrest, control of blood pressure and stress deprivation during the first days after subarachnoid haemorrhage. However, it cannot be excluded that withdrawal of nimodipine together with the general precautions in patients with unclipped aneurysms is responsible for the late peak of rebleeds. With regard to the timing of surgery, the low rebleed rates between days 1 and 3 justify semi-elective timing within this interval. On the other hand, in patients in whom aneurysm elimination has been deferred because of bad neurological condition or concomittant medical problems, surgery should be performed prior to the 4th week, unless the prognosis is considered hopeless at this time.     

Rebleeding of ruptured intracranial aneurysms in the acute stage

We analyzed early aneurysmal rebleeding in 150 consecutive patients who suffered an aneurysmal subarachnoid hemorrhage (SAH) and who were admitted within 6 hours of the initial SAH. Of these patients, 33 patients rebled. The first rebleed occurred within 24 hours in 29 patients, among whom 23 cases rebled within 6 hours. The rebleeding rate within 6 hours after the initial SAH was not related to age or sex of the patient; blood pressure on admission; size, shape, or site of aneurysm; or presence or absence of intracerebral hematoma or intraventricular hemorrhage on computed tomography (CT) scan. The patients' clinical condition and SAH on CT scan were graded I-V. Evaluation of rebleeding of those patients with grade V was difficult. In examining the rebleeding rate in grades I-IV, the higher the grade, the greater the rebleeding. Rebleeding developed during angiography conducted within 6 hours from the initial SAH in four cases. This is approximately twofold higher than the rebleeding rate within 6 hours for the total series. It is concluded that rebleeding in the acute stage is predominant within 6 hours from the initial SAH and that this rebleeding rate is higher the more severe the initial SAH is.     

Fatal subarachnoid hemorrhage after endoscopic third ventriculostomy. Case report.

In recent years, endoscopic third ventriculostomy has become a well-established procedure for the treatment of various forms of noncommunicating hydrocephalus. Endoscopic third ventriculostomy is considered to be an easy and safe procedure. Complications have rarely been reported in the literature. The authors present a case in which the patient suffered a fatal subarachnoid hemorrhage (SAH) after endoscopic third ventriculostomy. This 63-year-old man presented with confusion and drowsiness and was admitted in to the hospital in poor general condition. Computerized tomography scanning revealed an obstructive hydrocephalus caused by a tumor located in the cerebellopontine angle. An endoscopic third ventriculostomy was performed with the aid of a Fogarty balloon catheter. Some hours postoperatively, the patient became comatose. Computerized tomography scanning revealed a severe perimesencephalic-peripontine SAH and progressive hydrocephalus. Despite emergency external ventricular drainage, the patient died a few hours later. Although endoscopic third ventriculostomy is considered to be a simple and safe procedure, one should be aware that severe and sometimes fatal complications may occur. To avoid vascular injury, perforation of the floor of the third ventricle should be performed in the midline, halfway between the infundibular recess and the mammillary bodies, just behind the dorsum sellae.     

Surgical management of ruptured aneurysms in the eighth and ninth decades

Summary ?Background. The surgical management of elderly patients with aneurysmal subarachnoid haemorrhage (SAH) is controversial. The present study was performed to more clearly define issues facing elderly SAH patients undergoing surgical repair of their aneurysms. Method. Between 1990 and 2000, 100 patients, aged 70 years or older, were managed consecutively with aneurysmal surgical repair at Verona City Hospital. Ninety-seven of these were analysed with regard to age, clinical grade on admission, radiological features, and specific management components (3 patients were excluded from further analysis because of inadequate follow up data). Surviving patients were followed up for a minimum of 6 months and clinical outcome was assessed. Findings. Hydrocephalus requiring permanent CSF diversion occurred in 44% of cases surviving beyond 10 days from their SAH. The development of hydrocephalus requiring shunting was delayed more than 6 weeks in 7% of these cases. Medical complications occurred in 22% of cases. Clinical grade of haemorrhage (p<0.001), early hydrocephalus requiring ventriculostomy (p=0.003) and the development of medical complications (p=0.03) were significantly associated with poor outcome. Clinical vasospasm was not a major determinant of outcome in this group. The need for permanent CSF diversion was significantly associated with increasing age (p=0.03), intraventricular haemorrhage (p<0.001), early hydrocephalus requiring ventriculostomy (p=0.003) and the development of medical complications (p=0.05). Interpretation. Elderly patients experience a different range of complications following aneurysmal subarachnoid haemorrhage than their younger counterparts. Clinicians should remain alert to the development of hydrocephalus, especially of delayed onset. Published online June 11, 2003     

Dissecting aneurysm confined to the anterior cerebral artery

Dissecting aneurysm confined to the anterior cerebral artery (ACA) is extremely rare. Four patients presented with dissecting aneurysms confined to the ACA, two with cerebral infarctions in the territories of the ACA and two with subarachnoid haemorrhages. The two patients with infarction were treated by conservative therapy with anti-platelet therapy and the two patients with subarachnoid haemorrhage were treated by wrapping surgery in the early period after the ictus. Conservative treatment for patients with infarction and early wrapping surgery for patients with subarachnoid haemorrhage are recommended.     

Duration of cerebrospinal fluid drainage in patients with aneurysmal subarachnoid hemorrhage for prevention of symptomatic vasospasm and late hydrocephalus

The optimal duration of cerebrospinal fluid (CSF) drainage after acute aneurysm surgery is unclear. The association between the occurrence of symptomatic vasospasm or late hydrocephalus and the duration of CSF drainage was investigated using multiple logistic analysis in 95 consecutive patients with aneurysmal subarachnoid hemorrhage who underwent surgery within 72 hours after onset. The duration of drainage was significantly related to the occurrence of symptomatic vasospasm and late hydrocephalus. The cut-off values of the duration of drainage for preventing symptomatic vasospasm and late hydrocephalus were 11 days (adjusted odds ratio 0.347, 95% confidence interval 0.135-0.889, p = 0.0274) and 6 days (adjusted odds ratio 4.86, 95% confidence interval 1.46-16.2, p = 0.0099), respectively. Prevention of both symptomatic vasospasm and late hydrocephalus is not possible without additional procedures such as cisternal irrigation using fibrinolytic agents.