Endoscopic procedures for resection of arteriovenous malformations

Cerebral Arteriovenous Malformation Treatment by Full Transcranial Neuroendoscopic Approaches

BACKGROUND

Traditionally, cerebral arteriovenous malformations (cAVMs) are surgically treated with microscopy, and no cases receive full neuroendoscopy. We operated on two small cAVMs with hematoma under a neuroendoscope, and the two patients obtained excellent results.

OBJECTIVE

To explore the feasibility of treating cAVMs with a full transcranial neuroendoscopic approach.

METHODS

The clinical data and operative techniques were collected and described for two patients who were diagnosed with cAVMs with hematoma and treated via a full transcranial neuroendoscopic approach.

RESULTS

In the two patients, the hematomas were successfully evacuated, and the AVMs were removed simultaneously; both patients had achieved excellent recoveries at discharge.

CONCLUSION

To our knowledge, this is the first report in the literature to successfully treat cAVMs with hematoma with a full transcranial neuroendoscopic approach, showing that this approach is feasible and may be an alternative for small ruptured cAVMs. However, while the feasibility of attempting this approach was demonstrated, it was difficult to certify its obvious advantage. Nevertheless, we believe that this approach might be difficult for middle and large AVMs due to the shortcomings of neuroendoscopy. More cases and practice are needed to confirm the merits and limitations of this new approach for AVMs.

Anesthesia for Minimally Invasive Cranial and Spinal Surgery

The field of minimally invasive neurosurgery has evolved rapidly in its indications and applications over the last few years. New, less invasive techniques with low morbidity and virtually no mortality are replacing conventional neurosurgical procedures. Providing anesthesia for these procedures differs in many ways from conventional neurosurgical operations. Anesthesiologists are faced with the perioperative requirements and risks of newly developed procedures. This review calls attention to the anesthetic issues in various minimally invasive neurosurgical procedures for cranial and spinal indications. Among the procedures specifically discussed are endoscopic third ventriculostomy, endoscopic transsphenoidal hypophysectomy, endoscopic strip craniectomy, deep brain stimulation, video-assisted thorascopic surgery, vertebroplasty and kyphoplasty, cervical discectomy and foraminectomy, and laparoscopically assisted lumbar spine surgery.

Concept of arteriovenous malformation compartments and surgical management

Cerebral AVMs are known to be a source of intracranial hemorrhages and epileptic seizures. Their natural history indicates approximately 15% mortality and 35% morbidity over a 15-year period. This significant mortality and morbidity mandates a need for satisfactory treatment of this entity, ideally by elimination of AVMs. Microsurgical resection, endovascular embolization and radiosurgery (irradiation) are the three effective modes of treatment currently available. However, no objective criteria have been established for which mode(s) of treatment should be selected for individual patients with AVMs. Considering the complexity of AVMs and variable conditions of individual patients, neurosurgeons, intravascular interventionalists and radiosurgeons must make their own decisions on how to treat each patient based on their experience. In practice, treatment of small AVMs in non-functional areas is favored equally by each of these specialists, while they tend to avoid treatment of large AVMs, particularly those in functional areas of the brain. The authors report the surgical intervention of large AVMs, including those located in functional areas of the hemisphere by special techniques. One can demonstrate AVM compartments by using angiography and with the aid of color Doppler ultrasonography, each compartment can be outlined and dissected individually until all the compartments are isolated without causing any damage to the surrounding brain and the entire AVM is rendered shrunken and then removed. The concept of compartmental treatment of AVMs may be applied in the future to radiosurgery and intravascular embolization of large AVMs.

Pericapillary arteriovenous malformations angiographically manifested as cerebral venous malformations

Cerebral venous malformations have been diagnosed by angiographic features and are considered to be a benign anomaly. However, ample evidence indicates that stroke or similar symptomatology occurs in patients harboring a cerebral vascular malformation that was diagnosed angiographically as a venous malformation. The purpose of the study is to confirm the presence of a pericapillary arteriovenous malformation in these patients by analyzing the clinical history and surgical findings and correlating them with histological features. Thirteen patients were included in this study. Each patient fulfilled four criteria: 1. the patient was neurologically symptomatic; 2. the angiographic diagnosis was a venous malformation; 3. at operation, shunting arterioles (50-100 microns) were found to contribute to the malformation; and 4. histologically, a mixture of venous channels and arterioles with arterioles directly connected to venules was found. Based on the above findings, the malformation present in the 13 patients can be termed a 'pericapillary arteriovenous malformation'. Its angiographic distinction from the cerebral venous malformation requires technological advancement in the capability of magnifying images of arterioles and venules, along with improvement in image resolution.

Pediatric neuroanesthesia. Arteriovenous malformations

Intracranial arteriovenous malformations can occur singly, multiply, and in conjunction with aneurysms and denovo, family, or in conjunction with connective-tissue disorders. Intracranial hemorrhage is the most common presentation, occurring in 20% to 50% of cases. In children, seizures are the second most common presentation occurring in 15% to 20% of cases. The modalities available treatment of arteriovenous malformations are microsurgery, embolization, and stereotactic radiosurgery with heavy particles, alpha knife, or linear accelerator. Induction, maintenance, and emergence from anesthesia are designed to prevent rupture of arteriovenous malformation and aneurysm and to improve intracranial compliance in the presence of an intracranial hematoma, during both diagnostic (CT, MR scanning) and therapeutic procedures.

New concepts in adult brain arteriovenous malformations

Brain arteriovenous malformations are currently attracting increasing attention among clinicians as modern brain imaging techniques facilitate both diagnostic and follow-up evaluation. Their frequent presentation in young individuals, at times with flagrant clinical effects caused by cerebral hemorrhages or seizure disorders, keeps clinicians alert to any improvement in treatment strategies. Recent technical advances in surgical, endovascular, and radiation therapy add to the constantly accumulating data on clinical features, natural course, and treatment outcome in adult arteriovenous malformation patients. This review focuses on new concepts in arteriovenous malformation etiology, classification, treatment, and study approaches.