MAMC Journal of Medical Sciences

: 2016  |  Volume : 2  |  Issue : 2  |  Page : 76--80

Embolization of skull base tumors: Institutional experience

Vikas Kumar1, Hukum Singh1, Anita Jagetia1, Daljit Singh1, Monica S Tandon2, Pragati Ganjoo2, JC Passey3, Achal Gulati3,  
1 Department of Neurosurgery, G. B. Pant Institute of Postgraduate Medical Education and Research, New Delhi, India
2 Department of Anaesthesiology, G. B. Pant Institute of Postgraduate Medical Education and Research, New Delhi, India
3 Department of Otorhinolaryngology, Maulana Azad Medical College, New Delhi, India

Correspondence Address:
Daljit Singh
Room No. 529, Department of Neurosurgery, G. B. Pant Institute of Postgraduate Medical Education and Research, 1, J. L. N. Marg, New Delhi - 110 002


Introduction: The bleeding during surgery for tumors located at skull base can be torrential. The preoperative embolisation can minimize the blood loss and can create a comfortable environment for surgeon to operate these highly vascular tumors. Materials and Methods: The patients of various skull base tumors were divided into two groups. Group I included 45 patients not embolised prior to surgery and Group II included 37 patients who were embolised prior to surgery. Surgery was performed within 72 hours of the embolisaton. Patients in the two groups were compared for amount of blood loss, time during surgery, extent of tumor removal, complications, hospital stay and mortality. Comfort to surgeon during surgery was assessed by Pant Surgeons Satisfaction Score (PS3). Results: Amount of blood loss in Group I was more than 500 ml in majority as compared to Group II (P < 0.001).Operation room timings were more than 3 hours in Group I (P < 0.001). Similarly extent of surgery was better with lesser complications and mortality in Group II (P < 0.001).The hospital stay was less than 8 days in Group II (P < 0.001). Interestingly the operating surgeons were more comfortable and happy with their surgery if the patients were previously embolised i.e. PS3 of 3 or 4 (P< 0.001). Conclusion: Skull based tumors can be embolized in the preoperative period safely with the endovascular techniques to reduce the complications associated with surgical intervention.

How to cite this article:
Kumar V, Singh H, Jagetia A, Singh D, Tandon MS, Ganjoo P, Passey J C, Gulati A. Embolization of skull base tumors: Institutional experience.MAMC J Med Sci 2016;2:76-80

How to cite this URL:
Kumar V, Singh H, Jagetia A, Singh D, Tandon MS, Ganjoo P, Passey J C, Gulati A. Embolization of skull base tumors: Institutional experience. MAMC J Med Sci [serial online] 2016 [cited 2019 Oct 18 ];2:76-80
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Full Text


Surgery for skull base tumor is known for excessive bleeding. Most of the tumors are highly vascular and are deterrent to adequate removal. Bleeding during surgery can result in severe hemodynamic alterations and can even be fatal despite adequate replacement of blood.

The surgeons over the years have adopted various methods to control bleeding by ligating external carotid artery (ECA) or its branches. Accidental ligation of common carotid artery or internal carotid artery (ICA) is possible. Moreover, ligation results in permanent occlusion of the artery which can be of some utility at later stage of life particularly for (superficial temporal artery-middle cerebral artery anastomosis) certain illnesses of the brain. The excessive bleeding during surgery may result in suboptimal removal of tumors,[1] leading to increased morbidity, hospital stay, and mortality.

A novel method to control bleeding during surgery is preoperative embolization of tumor leading to devascularization so that tumor can be resected with ease.[2],[3] Most of the studies projecting the merits of embolization are from western literature. Most of the surgeons who refer their cases for embolization are happy; however, there are no objective criteria for that.

The aims of this study were to analyze the merits of embolization in terms of completeness of tumor removal, blood loss, and comfort to the surgeon during surgery and associated morbidity in Indian conditions.

 Materials and Methods

Patients were adequately hydrated before the procedure. The informed consent was obtained in all cases. The procedure was adequately explained to the patients or attendant. The case suitable for embolization was based on the experience of senior faculty in that case. It was essentially based on the contrast-enhancing pattern of the lesion and its size.

The embolization was performed under local anesthesia using retrograde transfemoral route (Seldinger's technique). A check flow of 5–6 F was introduced in the femoral artery. A long catheter of straight or angulated tip was advanced into feeding artery via arch of the aorta. Angiogram was performed using 4–5 F catheter. Selective catheterization was achieved in the ECA or ICA depending on the feeder to the tumors [Figure 1]. Super selective catheterization was performed using microcatheter 1.5–3 F into the branch of ECA or ICA or vertebral artery (VA) feeding the tumor [Figure 2]. The microcatheter was positioned as close to the tumor bed as possible so that no or minimal contrast was seen in the feeding artery.The microcatheter was repositioned if the contrast was seen flowing back into the feeding artery. All these procedures were performed using C-arm fluoroscopy with road map facility.{Figure 1}{Figure 2}

Angiogram was analyzed for size, number of feeding arteries, venous drainage, and aberrant connections between ECA and ICA or VA. Embolization was performed using PVA particles of 50–700 microns. A few cases were embolized with additional N-butyl cyanoacrylate. End point of embolization included near complete disappearance of tumor blush as seen in preembolized angiogram. Detachable coils were used in four cases to occlude the parent feeding artery [Figure 3],[Figure 4],[Figure 5].{Figure 3}{Figure 4}{Figure 5}

Intraoperative challenge tests, for example balloon occlusions and lignocaine challenge test, were performed whenever there was a likely risk of occlusion of carotid artery during surgery or impending damage to cranial nerves in the vicinity of tumor. As such most procedures were simple, and were performed by the experienced team. However, some difficulties during the procedure were encountered. These included local hematoma formation at femoral puncture site, feeling hot, flushing, or some pain at face during procedure. Selective and super selective catheterization added to more time and exposure to radiation. Patients were given intraoperative antibiotics only. Patients were subjected to definitive surgery within 72 h of embolization.

The analysis of various factors during surgery included amount of blood loss, extent of tumor removal, intraoperative complications, and time taken for surgery. Other analysis included length of hospital stay, comfort to surgeon during surgery (Pant Surgeon Satisfaction Score, PS3) [Table 1], and postoperative mortality.{Table 1}

Statistical analysis was performed using SPSS software (IBM), and a P < 0.001 was considered statistically significant.


The study was conducted at G. B. Pant Institute of Postgraduate Medical Education and Research from 2000 to 2008. The total number of patients included in this study was 82. There were 58 (70.7%) males and 24 (29.3%) females. The age of the patients was between 9 and 65 years.

The patients were divided into two groups. The Group I patients who were not embolized preoperatively and Group II were embolized. There were 45 patients in Group I and 37 in Group II. The various distribution of cases in two groups have been illustrated in [Table 2].{Table 2}

Both groups had inclusion of most cases having common pathology. The angiofibroma and esthesioneuroblastoma patients were operated by otorhinolaryngologists whereas meningiomas, metastasis, and glomus tumors were operated by neurosurgeons.

The various parameters that were compared in two groups are summarized in [Table 3].{Table 3}

Blood loss

The intraoperative blood loss was more than 500 ml in 12% of patients in Group II as compared to 87.5% in Group I (P < 0.001). The amount of blood loss was significantly controlled in angiofibroma and meningioma.

Timing of surgery

Operation room timing was more than 3 h in nearly 70% patients in Group I as compared to 18% in Group II (P < 0.001). The time taken for the surgery was significantly less in Group II.

Extent of surgery

Surgery was considered total or near total if the postoperative magnetic resonance imaging or contrast enhanced computed tomography revealed that tumor removal was > 90%. Any surgery < 90% was grouped together as subtotal. In two patients, only biopsy could be taken and both belonged to Group I. Near total removal was achieved in 88% of Group II patients whereas 67% patients in Group I had subtotal removal (P < 0.001).

PS3 surgeon comfort score

A subjective score after the name of Pant Hospital was evolved. Pant surgeons satisfaction score (PS3) was based on the feedback of surgeon, both from otorhinolaryngologists and neurosurgeons. After the definitive surgery, a subjective feeling of surgeons comfort was documented as the PS3 score. Surgeons were asked to share the experience of comfort and difficulties during surgery. The experience of surgery was based on amount of blood loss, extent of removal, intraoperative events, complications, and time taken for surgery. Nearly, 76% surgeons in Group I opted for score 1–2. Whereas in Group II 68% surgeons opted for higher score of 3–4 which was statistically significant (P < 0.001).

Duration of stay

Duration of stay was more in Group I as compared to Group II. Nearly, 80% patient had stay of < 8 days in Group II as compared with longer stay in Group I (P < 0.001). The stay of shorter duration in Group II was attributed to lesser complications during and after surgery in this group.


Various intraoperative complications included changes in hemodynamics, including fall in blood pressure and postoperative neurological or cranial nerve deficits. The complications were 20% in Group I as compared to 9% in Group II (P < 0.001). The complications related to embolization included pain during injection of embolisate, which was noticed in nearly 40% cases. Postembolization fever was observed in 10%. Contrast related events were observed in 5%. One patient had carotid dissection leading to transient hemiparesis which improved later.


In all, there were 11 deaths. Nine patients died in Group I whereas there were only two deaths in Group II (P < 0.001). The common causes of death were massive blood loss in Group I. Two patients in Group I had postoperative meningitis. The cause of death in Group II included myocardial infarction in one and pulmonary embolism in another.


Surgical resection of hypervascular central nervous system tumors can be a daunting task and is associated with staggering blood loss. To mitigate blood loss, several advances have been made in neuroendovascular techniques. The first descriptions of preoperative embolization of meningioma were performed by Manelfe et al.[4] Transcranial catheterization was later added to reduce blood loss and produce tumor necrosis resulting in reduced surgical time [5],[6] and recurrence.[7]

The several authors have reported a decline in blood loss following embolization to <500 ml and others have reported a reduction in blood loss from 2.5 L to 800 ml by embolization.[8],[9]

The technique of embolization has changed significantly over the years. Whereas carotid artery puncture was in practice earlier, femoral artery route is preferred now. Super selective catheterization has improved efficacy and safety. A careful assessment of angiography is necessary before planning a case for embolization. The presence of ECA-ICA anastomosis and shared arterial supply between tumor and surrounding nerves need to be assessed before embolization to prevent major complications.[10]

Beside branches from ECA, pial and dural branches from ICA contribute to vascularity. Pial vessels are best dealt with intraoperative direct puncture into the tumor.[10] There has been report of paradoxical migration of embolic agents from left to right heart in case of patent foramen ovale leading to stroke or pulmonary embolism.[11] Some of the important feeders to these tumor include ascending pharyngeal artery, recurrent meningeal artery, branches from maxillary artery, vidian artery, and others.[10] Branches from ICA contribute significantly to several tumor supply and can be dealt with balloon occlusions and liquid embolizing agents.[12]

Optimal timing for embolization is still controversial. Whereas some interventionists advocate early intervention within 5 days, others advocate later surgery at 1–2 weeks. There is always a risk of recanalization if surgery is delayed by more than 1 week. There is evidence of recanalization within 72 h as well.[13],[14] Hence, the best-suited timings are to be decided by the surgeon depending on the availability of operation theater, the goal of surgery and self-confidence.

Intraoperative pain is one of the most common complaints. Transient neurological deficit,[15] scalp necrosis [16] and hemorrhage [16],[17] have been reported by several authors. There are reports of change in histological features of the tumor following embolization.[18]

Some authors advocate embolization only if tumor size is more than 3 cm [19],[20] however such observations may not be universally adhered. Care is needed in embolizing patients with glomus tumor. These patient should be pretreated with alpha and beta blockers before embolization.[21],[22]

There is however no study which describes the benefits of surgery in relation to benefits other than blood loss. There are several other advantages of embolization besides minimizing blood loss. It allows the surgeon to perform wider resection, minimizes intraoperative complications and reduces hospital stay. Moreover, the operating surgeon is more comfortable as he can do better resections because the blood loss is less and operation field is cleaner; hence, they are more satisfied.


Embolization of the skull base tumor is a useful adjunct in its treatment. It should be performed whenever the surgeon expects torrential blood loss. The optimizing time for surgery is 72 h following embolization. Embolization significantly reduces the blood loss, reduces complications and helps surgeons to perform adequate surgery with comfort and ease.

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Conflicts of interest

There are no conflicts of interest.


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