Cerebral arteriovenous malformations: Pathogenesis Update

 

The pathogenesis of cerebral arteriovenous malformations (cAVMs) is still not well understood. Generally, cAVMs are thought to be congenital lesions originating prenatally.

AVMs are usually congenital and belong to the RASopathies. The genetic transmission patterns of AVM, if any, are unknown. AVM is not generally thought to be an inherited disorder, unless in the context of a specific hereditary syndrome.

A long-held dogma in neurosurgery is that parenchymal arteriovenous malformations (AVMs) are congenital. However, there is no strong evidence supporting this theory. An increasing number of documented cases of de novo formation of parenchymal AVMs cast doubt on their congenital nature and suggest that indeed the majority may form after birth. Further evidence suggesting the postnatal development of parenchymal AVMs comes from the exceedingly rare diagnosis of these lesions in utero despite the widespread availability of high-resolution imaging modalities such as ultrasound and fetal MRI. The exact mechanism of AVM formation has yet to be elucidated, but most likely involves genetic susceptibility and environmental triggering factors 1).

Molecular and cellular biology

A PubMed search was performed using the key words “genetic,” “molecular,” “brain,” “cerebral,” “arteriovenous,” “malformation,” “rupture,” “management,” “embolization,” and “radiosurgery.” Only English-language papers were considered. The reference lists of all papers selected for full-text assessment were reviewed.

Current concepts in genetic polymorphisms, growth factors, angiopoietins, apoptosis, endothelial cells, pathophysiology, clinical syndromes, medical treatment (including tetracycline and microRNA-18a), radiation therapy, endovascular embolization, and surgical treatment as they apply to AVMs are discussed.

Understanding the complex cellular biology, physiology, hemodynamics, and flow-related phenomena of AVMs is critical for defining and predicting their behavior, developing novel drug treatments, and improving endovascular and surgical therapies 2).

1) Morales-Valero SF, Bortolotti C, Sturiale CL, Lanzino G. Are parenchymal AVMs congenital lesions? Neurosurg Focus. 2014 Sep;37(3):E2. doi:10.3171/2014.6.FOCUS14234. PubMed PMID: 25175439.
2) Rangel-Castilla L, Russin JJ, Martinez-Del-Campo E, Soriano-Baron H, Spetzler RF, Nakaji P. Molecular and cellular biology of cerebral arteriovenous malformations: a review of current concepts and future trends in treatment. Neurosurg Focus. 2014 Sep;37(3):E1. doi: 10.3171/2014.7.FOCUS14214. PubMed PMID: 25175428.

Obsessive compulsive disorder (OCD) : Evidence Update

It is estimated that 40% to 60% of patients with obsessive-compulsive disorder (OCD) continue to experience symptoms despite adequate medical treatment.

For treatment-refractory patients, promising results have been reported with the use of deep brain stimulation (DBS).

Based on the data published in the literature, the following recommendations can be made:

(1) There is Level of evidence 1, based on a single class 1 study, for the use of bilateral subthalamic deep brain stimulation for the treatment of medically refractory OCD.

(2) There is Level of evidence 2, based on a single class 2 study, for the use of bilateral nucleus accumbens DBS for the treatment of medically refractory OCD.

(3) There is insufficient evidence to make a recommendation for the use of unilateral DBS for the treatment of medically refractory OCD 1).

1) Hamani C, Pilitsis J, Rughani AI, Rosenow JM, Patil PG, Slavin KS, Abosch A, Eskandar E, Mitchell LS, Kalkanis S. Deep Brain Stimulation for Obsessive-Compulsive Disorder: Systematic Review and Evidence-Based Guideline Sponsored by the American Society for Stereotactic and Functional Neurosurgery and the Congress of Neurological Surgeons (CNS) and Endorsed by the CNS and American Association of Neurological Surgeons. Neurosurgery. 2014 Oct;75(4):327-333. PubMed PMID: 25050579.

New proposed classification for lumbar and thoracolumbar deformity

Lumbar and thoracolumbar deformity in the adult is a condition with impairment of health status that can need surgical treatment.

Classification

In contrast with adolescent spinal deformity, where magnitude of the spinal curvature plays a significant role in surgical indication, the aspects relevant in adult spinal deformity are pain and dysfunction that correlate with segment degeneration and imbalance. Previous classifications of adult deformity have been of little use for surgical planning.

Berjano and Lamartina from the IVth Spine Surgery Division, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy, presented a chart review and classification of radiographic and clinical findings.

A classification of degenerative disc disease based on distribution of diseased segments and balance status of the spine is presented.

Four main categories are presented:

Type I (limited nonapical segment disease)

Type II (limited apical segment disease)

Type III (extended segment disease-apical and non apical)

Type IV (imbalanced spine: IVa, sagittally imbalanced; IVb, sagittally and coronally imbalanced).

Types I and II can be treated by fusion of a selective area of the curve.

Type III needs fusion of all the extension of the coronal curve.

Type IV usually needs aggressive corrective procedures, frequently including posterior tricolumnar spine osteotomy. This classification permits interpreting the extension, magnitude and can help establish a surgical plan regarding selective fusion and methods of sagittal correction. Future research is needed to validate the classification 1).

1) Berjano P, Lamartina C. Classification of degenerative segment disease in adults with deformity of the lumbar or thoracolumbar spine. Eur Spine J. 2014 Sep;23(9):1815-24. doi: 10.1007/s00586-014-3219-9. Epub 2014 Feb 23. PubMed PMID: 24563272.

Today: 2014 Congress of the European Society of Stereotactic and Functional Neurosurgery (“Implementing Research in Clinical Applications”)

2014 Congress of the European Society of Stereotactic and Functional Neurosurgery (“Implementing Research in Clinical
Applications”)

SEPTEMBER 17-20, 2014

Maastricht,
The Netherlands

WEB SITE: www.essfn2014.org

Program

European Society of Stereotactic and Functional Neurosurgery