Intraoperative ultrasound (IoUS) guided resection of Gliomas: A Meta-analysis and review of the literature

Abstract Introduction Image guided surgery has become standard practice during surgical resection, using preoperative MRI. Intraoperative-ultrasound has attracted interest, because of its perceived safety, portability, and real-time imaging. This is a meta-analysis of intraoperative-ultrasound in gliomas. Methods Critical literature review and meta-analyses, using MEDLINE/PubMed service. The list of references in each article was double-checked for any missing references. We included all studies that reported the use of ultrasound to guide glioma-surgery. The meta-analyses were conducted according to statistical heterogeneity between the studies using Open MetaAnalyst Software. If there was no heterogeneity, fixed effects model was used for meta-analysis; otherwise, a random effect model was used. Statistical heterogeneity was explored by χ2 and inconsistency (I2 ) statistics; an I2 value of 50 percent or more represented substantial heterogeneity. Results Casting a wide-net search caught 19,109 studies that might be relevant, of which 4,819 were ultrasound in neurosurgery. 756 used ultrasound in cranial surgery, of which 24 studies used intraoperative ultrasound to guide surgical resection and 74 to guide biopsy. Fifteen studies fulfilled our stringent inclusion criteria, giving a total of 739 patients. The estimated average gross total resection rate was 77%. Furthermore, the relationship between extent of surgical resection and study population was not linear. GTR was more likely under IoUS when the lesion was solitary, subcortical, and no past history of surgery or radiotherapy. IoUS image quality, sensitivity, and specificity, positive & negative predictive values deteriorated as surgical resection proceeded. Conclusion IoUS guided surgical resection of gliomas is a useful tool for guiding the resection and of value in improving the extent of resection. IoUS can be used in conjunction with other complementary technologies that can improve anatomical orientation during surgery. Real-time imaging, improved image quality, small probe sizes, repeatability, portability, and relatively low cost made IoUS a realistic cost effective tool that complements any existing tools in any neurosurgical operating environment.