Heather Smith, AmiLyn Taplin, Sohail Syed and Matthew A. Adamo
Malignant disease of the CNS is the primary etiology for deaths resulting from cancer in the pediatric population. It has been well documented that outcomes of pediatric neurosurgery rely on the extent of tumor resection. Therefore, techniques that improve surgical results have significant clinical implications. Intraoperative ultrasound (IOUS) offers real-time surgical guidance and a more accurate means for detecting residual tumor that is inconspicuous to the naked eye. The objective of this study was to evaluate the correlation of extent of resection between IOUS and postoperative MRI. The authors measured the correlation of extent of resection, negative predictive value, and sensitivity of IOUS and compared them with those of MRI.
This study consisted of a retrospective review of the medical charts of all pediatric patients who underwent neurosurgical treatment of a tumor between August 2009 and July 2015 at Albany Medical Center. Included were patients who were aged ≤ 21 years, who underwent brain or spinal tumor resection, for whom IOUS was used during the tumor resection, and for whom postoperative MRI (with and without contrast) was performed within 1 week of surgery.
Sixty-two patients met inclusion criteria for the study (33 males, mean age 10.0 years). The IOUS results very significantly correlated with postoperative MRI results (φ = 0.726; p = 0.000000011; negative predictive value 86.3% [95% CI 73.7%–94.3%]). These results exemplify a 71% overall gross-total resection rate and 80% intended gross-total resection rate with the use of IOUS (i.e., excluding cases performed only for debulking purposes).
The use of IOUS may play an important role in achieving a greater extent of resection by providing real-time information on tumor volume and location in the setting of brain shift throughout the course of an operation. The authors support the use of IOUS in pediatric CNS tumor surgery to improve clinical outcomes at low cost with minimal additional operating-room time and no identified additional risk.
Jared F. Sweeney, Heather Smith, AmiLyn Taplin, Eric Perloff and Matthew A. Adamo
Intraoperative ultrasonography (IOUS) is a widely accessible imaging modality that provides real-time surgical guidance with minimal identified risk or additional operative time. A recent study by the authors found a strong correlation between IOUS and postoperative MRI findings when evaluating the extent of tumor resection, suggesting that IOUS might have significant clinical implications. The objective of this study was to expand on results from the previous study in order to provide more evidence on the usage of IOUS in the determination of gross-total resection (GTR) in both adult and pediatric patients with brain tumors.
This study consisted of a retrospective review of adult and pediatric neurosurgical patients who were treated at Albany Medical Center between August 2009 and March 2016 for a tumor of the brain. All patients were treated with IOUS and then underwent postoperative MRI (with and without contrast) within 1 week of surgery.
A total of 260 patients (55% of whom were males) met inclusion criteria for the study (age range 3 months to 84 years). IOUS results showed a strong association with postoperative MRI results (φ = 0.693, p < 0.001) and an 81% intended GTR rate. In cases in which GTR was pursued, 19% had false-negative results. IOUS was able to accurately identify residual tumor in 100% of subtotal resection cases where resection was stopped due to invasion of tumor into eloquent locations. Cases involving gliomas had a 75% intended GTR rate and a 25% false-negative rate. Cases involving metastatic tumors had an 87% intended GTR rate and a 13% false-negative rate. The sensitivity, specificity, negative predictive value, and positive predictive value are reported for IOUS in all included tumor pathologies, glioma cases, and metastatic tumor cases, respectively.
The use of IOUS may allow for a reliable imaging modality to achieve a more successful GTR of brain tumors in both adult and pediatric neurosurgical patients. When attempting GTR, the authors demonstrated an 81% GTR rate. The authors also report false-negative IOUS results in 19% of attempted GTR cases. The authors support the use of IOUS in both adult and pediatric CNS tumor surgery to improve surgical outcomes. However, further studies are warranted to address existing limitations with its use to further improve its efficacy and better define its role as an intraoperative imaging tool.