Invasion of the internal carotid artery by cavernous sinus meningiomas.

BACKGROUND: Meningiomas are the most common tumor involving the cavernous sinus. Although these tumors have been known to invade adjacent structures such as bone, soft tissue, and brain, invasion of the internal carotid artery (ICA) by meningiomas has only been recognized recently. The authors evaluate the extent of carotid wall involvement in nine patients with cavernous sinus meningiomas encasing the ICA who underwent en bloc resection of the cavernous sinus. METHODS: The en bloc tumor-ICA specimens were fixed in formalin, embedded in paraffin, and sectioned on a rotary microtome. Hematoxylin and eosin, EVG, and HVG stains were performed and evaluated by light microscopy. RESULTS: There were four males and five females with a mean age of 47 years. Eight patients had not undergone previous surgery, whereas one patient had been operated on before. In this latter case, however, the cavernous sinus was not entered during the first operation. In all patients, stenosis of the ICA was confirmed by preoperative angiography and/or magnetic resonance imaging (MRI). In seven cases, the tumors were excised en bloc along with the stenotic ICA segment. A petrous-to-supraclinoid ICA bypass was performed in these seven patients. In two cases, the tumor was excised with the stenotic artery, but no bypass was performed. The final pathological diagnosis was meningothelial meningioma. In all cases tumor cells were found in the adventitia of the cavernous carotid with stenosis of the arterial lumen. Compression and/or obliteration of the vasa vasorum within the adventia was noted in all specimens. In four cases, the tumor was found to have invaded the external elastic lamina. In two instances the external elastic lamina was disrupted and the tumor focally extended into the media. CONCLUSIONS: These findings suggest that in the case of cavernous sinus meningiomas with encasement and stenosis of the intracavernous ICA, invasion of the vessel wall has occurred. The effect of these findings on the management of cavernous sinus meningiomas and the involved ICA is discussed.

Craniofacial suture stenosis: morphologic effects.

Craniofacial anomalies, such as Apert's and Crouzon's syndromes, are presumed to be related to premature growth arrest of cranial base growth sites. However, premature growth arrest at cranial vault sutures in animals appears to play a causative role in the development of cranial deformities characteristic of single-suture, or simple, craniosynostosis in humans. To study the possible causative role of cranial vault and other (interface) suture stenoses on the development of craniofacial deformity, a vault suture and an interface suture between the cranial vault and facial skeleton were simultaneously immobilized. Thirty-one New Zealand White rabbits at 9 days of age underwent implantation of dental amalgam growth markers adjacent to cranial vault and facial sutures. In the experimental group (n = 15), methylcyanoacrylate adhesive was applied over the coronal (vault) and frontonasal (interface suture between vault and facial skeleton) sutures to immobilize them. The remaining 16 animals served as sham-treated controls. All animals underwent serial radiographic cephalometry to document growth effects in the cranial vault, cranial base, and facial skeleton. Application of adhesive resulted in statistically significant (p less than 0.05) reduction in growth at the coronal and frontonasal sutures. This was accompanied by an overall significant reduction in neurocranial vault length during the first 30 days of development.(ABSTRACT TRUNCATED AT 250 WORDS)

Skull base expansion: craniofacial effects.

In order to determine what effect the anterior cranial base has on the developing craniofacial skeleton, mechanical expansion of the growth of one segment of the anterior cranial base was performed. New Zealand white rabbits were used for this study. A sham-treated group (n = 16) underwent implantation of dental amalgam markers to either side of the frontonasal, coronal, and lambdoid sutures at 9 days of age to serve as markers of vault growth. The experimental group (n = 7) underwent the same marker placement at 9 days of age, but, in addition, at 30 days of age these animals underwent placement of a mechanical spring, unilaterally, at the frontosphenoid suture. A second control group (n = 8) underwent the same exposure of the frontosphenoid suture, but the spring was laid only on the surface of the bone. All animals were followed by radiographic cephalometry at 9, 30, 60, and 90 days of age. The experimental group demonstrated statistically significant expansion of the cranial base and ipsilateral coronal suture. The midface skeletal dimensions were unchanged by spring distraction of the cranial base. These findings indicate that cranial base sutural growth can be manipulated mechanically and that growth changes can be attained secondarily in the cranial vault skeleton.