Evan D. Bander, Samuel H. Jones, Ilhami Kovanlikaya and Theodore H. Schwartz
Brain retraction systems are frequently required to achieve surgical exposure of deep-seated brain lesions. Spatula-based systems can be associated with injury to the cortex and deep white matter, particularly adjacent to the sharp edges, which can result in uneven pressure on the parenchyma over the course of a long operation. The use of tubular retractor systems has been proposed as a method to overcome these limitations. There have been no studies assessing the degree of brain injury associated with the use of tubular retractors.
Twenty patients were retrospectively identified at Weill Cornell Medical College who underwent resection of deep-seated brain lesions between 2005 and 2014 with the aid of a METRx tubular retractor system. Using the Brainlab software, pre- and postoperative images were analyzed to assess volume, depth, extent of resection, and change in postoperative MR FLAIR hyperintensity and restricted diffusion on diffusion-weighted imaging (DWI).
The mean preoperative tumor volume was 16.25 ± 17.6 cm3. Gross-total resection was achieved in 75%, near-total resection in 10%, and subtotal resection in 15% of patients. There was a small but not statistically significant increase in average FLAIR hyperintensity volume by 3.25 ± 10.51 cm3 (p = 0.16). The average postoperative volume of DWI high signal area with restricted diffusion on apparent diffusion coefficient maps was 8.35 ± 3.05 cm3. Assuming that the volume of restricted diffusion on DWI around tumor was 0 preoperatively, this represented a statistically significant increase on DWI (p < 0.001).
Although tubular retractors do not appear to significantly increase FLAIR signal in the brain, DWI intensity around the retractors can be identified. These data indicate that although tubular retractors may minimize damage to surrounding tissues, they still cause cytotoxic edema and cellular damage. Objective comparison against other retraction methods, as compared by 3D volumetric analysis or similar methods, will be important in determining the true advantage of tubular retractor systems.
A. Gabriella Wernicke, Menachem Z. Yondorf, Luke Peng, Samuel Trichter, Lucy Nedialkova, Albert Sabbas, Fridon Kulidzhanov, Bhupesh Parashar, Dattatreyudu Nori, K. S. Clifford Chao, Paul Christos, Ilhami Kovanlikaya, Susan Pannullo, John A. Boockvar, Philip E. Stieg and Theodore H. Schwartz
Resected brain metastases have a high rate of local recurrence without adjuvant therapy. Adjuvant whole-brain radiotherapy (WBRT) remains the standard of care with a local control rate > 90%. However, WBRT is delivered over 10–15 days, which can delay other therapy and is associated with acute and long-term toxicities. Permanent cesium-131 (131Cs) implants can be used at the time of metastatic resection, thereby avoiding the need for any additional therapy. The authors evaluated the safety, feasibility, and efficacy of a novel therapeutic approach with permanent 131Cs brachytherapy at the resection for brain metastases.
After institutional review board approval was obtained, 24 patients with a newly diagnosed metastasis to the brain were accrued to a prospective protocol between 2010 and 2012. There were 10 frontal, 7 parietal, 4 cerebellar, 2 occipital, and 1 temporal metastases. Histology included lung cancer (16), breast cancer (2), kidney cancer (2), melanoma (2), colon cancer (1), and cervical cancer (1). Stranded 131Cs seeds were placed as permanent volume implants. The prescription dose was 80 Gy at a 5-mm depth from the resection cavity surface. Distant metastases were treated with stereotactic radiosurgery (SRS) or WBRT, depending on the number of lesions. The primary end point was local (resection cavity) freedom from progression (FFP). Secondary end points included regional FFP, distant FFP, median survival, overall survival (OS), and toxicity.
The median follow-up was 19.3 months (range 12.89–29.57 months). The median age was 65 years (range 45–84 years). The median size of resected tumor was 2.7 cm (range 1.5–5.5 cm), and the median volume of resected tumor was 10.31 cm3 (range 1.77–87.11 cm3). The median number of seeds used was 12 (range 4–35), with a median activity of 3.82 mCi per seed (range 3.31–4.83 mCi) and total activity of 46.91 mCi (range 15.31–130.70 mCi). Local FFP was 100%. There was 1 adjacent leptomeningeal recurrence, resulting in a 1-year regional FFP of 93.8% (95% CI 63.2%–99.1%). One-year distant FFP was 48.4% (95% CI 26.3%–67.4%). Median OS was 9.9 months (95% CI 4.8 months, upper limit not estimated) and 1-year OS was 50.0% (95% CI 29.1%–67.8%). Complications included CSF leak (1), seizure (1), and infection (1). There was no radiation necrosis.
The use of postresection permanent 131Cs brachytherapy implants resulted in no local recurrences and no radiation necrosis. This treatment was safe, well tolerated, and convenient for patients, resulting in a short radiation treatment course, high response rate, and minimal toxicity. These findings merit further study with a multicenter trial.
John A. Boockvar, Apostolos J. Tsiouris, Christoph P. Hofstetter, Ilhami Kovanlikaya, Sherese Fralin, Kartik Kesavabhotla, Stephen M. Seedial, Susan C. Pannullo, Theodore H. Schwartz, Philip Stieg, Robert D. Zimmerman, Jared Knopman, Ronald J. Scheff, Paul Christos, Shankar Vallabhajosula and Howard A. Riina
The authors assessed the safety and maximum tolerated dose of superselective intraarterial cerebral infusion (SIACI) of bevacizumab after osmotic disruption of the blood-brain barrier (BBB) with mannitol in patients with recurrent malignant glioma.
A total of 30 patients with recurrent malignant glioma were included in the current study.
The authors report no dose-limiting toxicity from a single dose of SIACI of bevacizumab up to 15 mg/kg after osmotic BBB disruption with mannitol. Two groups of patients were studied; those without prior bevacizumab exposure (naïve patients; Group I) and those who had received previous intravenous bevacizumab (exposed patients; Group II). Radiographic changes demonstrated on MR imaging were assessed at 1 month postprocedure. In Group I patients, MR imaging at 1 month showed a median reduction in the area of tumor enhancement of 34.7%, a median reduction in the volume of tumor enhancement of 46.9%, a median MR perfusion (MRP) reduction of 32.14%, and a T2-weighted/FLAIR signal decrease in 9 (47.4%) of 19 patients. In Group II patients, MR imaging at 1 month showed a median reduction in the area of tumor enhancement of 15.2%, a median volume reduction of 8.3%, a median MRP reduction of 25.5%, and a T2-weighted FLAIR decrease in 0 (0%) of 11 patients.
The authors conclude that SIACI of mannitol followed by bevacizumab (up to 15 mg/kg) for recurrent malignant glioma is safe and well tolerated. Magnetic resonance imaging shows that SIACI treatment with bevacizumab can lead to reduction in tumor area, volume, perfusion, and T2-weighted/FLAIR signal.