The role of preoperative embolization for intracranial meningiomas: A review
Ashish H. Shah, Neal Patel, Daniel M. S. Raper, Amade Bregy, Ramsey Ashour, Mohamed Samy Elhammady, Mohammad Ali Aziz-Sultan , Jacques J. Morcos, Roberto C. Heros, Ricardo J. Komotar J Neurosurg. 2013 Aug;119(2):364-72. doi: 10.3171/2013.3.JNS121328
Context: Since the 1970s the use of preoperative embolisation of meningiomas has become more common, however strong evidence to support its effectiveness and conclusive data on the associated complications is lacking. Its use varies widely among units and individual surgeons. To clarify the role of preoperative embolisation in the management of meningiomas, the authors conducted a systematic review of case reports, case series and prospective studies.
Methods: The authors performed a literature search using PubMed. They included all English language papers with human beings as subjects between 1990 and 2011, and searched for the terms “Meningiomas”, “Preoperative embolisation” and “Embolisation, Therapeutic”. They only included articles where embolisation was prior to and use as an adjunct for surgery, and excluded commentaries, editorials, articles focusing on technique and those that did not report surgical outcome. Studies were separated into groups based upon embolic material and tumour location, and were analysed for embolisation induced complications. Complications were defined as major if they represented sustained new deficits, or minor if they were transient and resolved. No statistical tests were performed.
Results: 36 out of 212 articles found were included in the qualitative analysis including 9 retrospective studies, 7 prospective studies and 20 case reports. A total of 459 patients were include in the study, 66% of whom were female, 40.2% convexity lesions, 15% sphenoidal, 8.4% parasagittal, and 6.5% petroclival.
The average time until surgery after embolisation was 6.3 days (range 0-30). One study looked at delayed surgery finding that these cases had slightly less bleeding (337.5ml vs 475ml, p <0.01).
Complications were reported in 21 of the 459 patients (4.6%), 18 of which were minor, 1 major and 2 fatal. These included infection, hemiparesis, facial palsy, DIC, glaucoma, tumour swelling, transient SIADH, dysphagia and cranial nerve deficit. The major complication was permantent blindness as a result of embolisation in a 60 year old man. The two fatalities were due to a cerebral infarction in a 37-year-old and a CNS infection in a 45 year old, both a direct result of embolisation.
Conclusion: The significant advances made in endovascular techniques over the last decade have opened up its utilization for a wider variety of meningiomas. Embolisation has a number of potential benefits including decreased operative blood loss, shorter operative time, and increased tumour necrosis and tumour softening. It is not without complication including risk of stroke, haemorrhage oedema and infection. In their study the authors found that the most commonly reported benefits in the literature were tumour softening and reduced operative blood loss. They suggest that the reduced blood loss was particularly beneficial for highly vascular tumours and orbital lesions, and complex meningiomas associated with vascular lesions or aneurysms. They also found that preoperative embolisation was associated with a number of significant complications. They report an immediate complication rate of 4.6% but also report an average complication rate of 6.8% in 749 embolised tumours from articles that were excluded from their analysis. This suggests that for every 20 patients that undergoes preoperative embolisation 1 will suffer a direct consequence, either transient or sustained. They do not make any judgement on the added benefit of reduced surgical mortality to analyse this figure against as they do not compare surgical outcomes in an embolised and a non embolised group.
Timing of surgery after embolisation has only been investigated in two papers to date, both of which concluded that a delayed operative course of over 24h was effective in reducing intraoperative bleeding. The authors suggest that based on their review, delaying surgery after embolization may not significantly increase the risk, however based on anecdotal evidence of cases where embolization resulted in significant oedema and the need for emergency surgery it is important to monitor the patient closely between embolization and surgery to ensure a prompt diagnosis and management of any complication.
One reason why embolization is not more prevalent is that in large cranial vault meningiomas amenable to embolisation, the main blood supply tends to arise from the branches of the superficial temporal, occipital, middle meningeal or posterior meningeal arteries, which are all usually accessible early during surgical exposure. The authors suggest that the tumours with most to gain from preoperative embolisation are giant convexity meningiomas with complicated and multidirectional blood supply, and those associated with a vascular abnormality such as a concurrent aneurysm. Their review comprises class III evidence and is subject to the selection biases found in the original articles. Further study is required, however it is clearly important to factor the risks of embolisation when considering whether to utilise it prior to meningioma surgery.
Chris Mansi MB BS MA (Cantab) MRCS
Methods: The authors performed a literature search using PubMed. They included all English language papers with human beings as subjects between 1990 and 2011, and searched for the terms “Meningiomas”, “Preoperative embolisation” and “Embolisation, Therapeutic”. They only included articles where embolisation was prior to and use as an adjunct for surgery, and excluded commentaries, editorials, articles focusing on technique and those that did not report surgical outcome. Studies were separated into groups based upon embolic material and tumour location, and were analysed for embolisation induced complications. Complications were defined as major if they represented sustained new deficits, or minor if they were transient and resolved. No statistical tests were performed.
Results: 36 out of 212 articles found were included in the qualitative analysis including 9 retrospective studies, 7 prospective studies and 20 case reports. A total of 459 patients were include in the study, 66% of whom were female, 40.2% convexity lesions, 15% sphenoidal, 8.4% parasagittal, and 6.5% petroclival.
The average time until surgery after embolisation was 6.3 days (range 0-30). One study looked at delayed surgery finding that these cases had slightly less bleeding (337.5ml vs 475ml, p <0.01).
Complications were reported in 21 of the 459 patients (4.6%), 18 of which were minor, 1 major and 2 fatal. These included infection, hemiparesis, facial palsy, DIC, glaucoma, tumour swelling, transient SIADH, dysphagia and cranial nerve deficit. The major complication was permantent blindness as a result of embolisation in a 60 year old man. The two fatalities were due to a cerebral infarction in a 37-year-old and a CNS infection in a 45 year old, both a direct result of embolisation.
Conclusion: The significant advances made in endovascular techniques over the last decade have opened up its utilization for a wider variety of meningiomas. Embolisation has a number of potential benefits including decreased operative blood loss, shorter operative time, and increased tumour necrosis and tumour softening. It is not without complication including risk of stroke, haemorrhage oedema and infection. In their study the authors found that the most commonly reported benefits in the literature were tumour softening and reduced operative blood loss. They suggest that the reduced blood loss was particularly beneficial for highly vascular tumours and orbital lesions, and complex meningiomas associated with vascular lesions or aneurysms. They also found that preoperative embolisation was associated with a number of significant complications. They report an immediate complication rate of 4.6% but also report an average complication rate of 6.8% in 749 embolised tumours from articles that were excluded from their analysis. This suggests that for every 20 patients that undergoes preoperative embolisation 1 will suffer a direct consequence, either transient or sustained. They do not make any judgement on the added benefit of reduced surgical mortality to analyse this figure against as they do not compare surgical outcomes in an embolised and a non embolised group.
Timing of surgery after embolisation has only been investigated in two papers to date, both of which concluded that a delayed operative course of over 24h was effective in reducing intraoperative bleeding. The authors suggest that based on their review, delaying surgery after embolization may not significantly increase the risk, however based on anecdotal evidence of cases where embolization resulted in significant oedema and the need for emergency surgery it is important to monitor the patient closely between embolization and surgery to ensure a prompt diagnosis and management of any complication.
One reason why embolization is not more prevalent is that in large cranial vault meningiomas amenable to embolisation, the main blood supply tends to arise from the branches of the superficial temporal, occipital, middle meningeal or posterior meningeal arteries, which are all usually accessible early during surgical exposure. The authors suggest that the tumours with most to gain from preoperative embolisation are giant convexity meningiomas with complicated and multidirectional blood supply, and those associated with a vascular abnormality such as a concurrent aneurysm. Their review comprises class III evidence and is subject to the selection biases found in the original articles. Further study is required, however it is clearly important to factor the risks of embolisation when considering whether to utilise it prior to meningioma surgery.
Chris Mansi MB BS MA (Cantab) MRCS
Consultant comment
