Thrombin hemostatic matrix leading to acute cerebral edema and sterile fluid collection formation post-tumor resection: two cases

Gelatin–thrombin Hemostatic Matrix-related Cyst Formation after Cerebral Hematoma Evacuation: A Report of Two Cases

The gelatin–thrombin matrix, Floseal, is an excellent novel hemostatic agent that is used in various surgical fields. Thrombin is a serine protease, and the conversion of prothrombin to thrombin is an essential step in the coagulation cascade. However, thrombin can induce blood–brain barrier (BBB) disruption and vasogenic brain edema. This report describes two cases of gelatin–thrombin matrix-related cyst formation after cerebral hematoma evacuation. An 82-year-old man with a gelatin–thrombin matrix-related cyst was treated by cyst drainage and fenestration to the lateral ventricle. Histological evaluation of the cyst wall showed a gelatin–thrombin matrix reserve, marked infiltration of inflammatory cells, and foam cell accumulation. In addition, an 85-year-old woman with a gelatin–thrombin matrix-related cyst was treated with steroids and responded well. In both cases, the post-treatment course was uneventful. Cyst shrinkage and no recurrence were observed. The gelatin–thrombin matrix can cause cyst formation with brain edema. This is the first report demonstrating the cyst wall pathology and the steroid responsivity on cyst shrinkage. The mechanism of cyst formation is thought to be thrombin-induced BBB disruption. Excess gelatin–thrombin matrix should be carefully removed from the surgical beds, particularly those having a blinded space from the neurosurgical microscope.

An anti-inflammatory gelatin hemostatic agent with biodegradable polyurethane nanoparticles for vulnerable brain tissue

Hemostasis plays a fundamental and critical role in all surgical procedures. However, the currently used topical hemostatic agents may at times undesirably induce inflammation, infection, and foreign body reaction and hamper the healing process. This may be serious in the central nervous system (CNS), especially for some neurosurgical diseases which have ongoing inflammation causing secondary brain injury. This study was aimed to develop a hemostatic agent with anti-inflammatory property by incorporating carboxyl-functionalized biodegradable polyurethane nanoparticles (PU NPs) and to evaluate its functionality using a rat neurosurgical model. PU NPs are specially-designed anti-inflammatory nanoparticles and absorbed by a commercially available hemostatic gelatin powder (Spongostan™). Then, the gelatin was implanted to the injured rat cortex and released anti-inflammatory PU NPs. The time to hemostasis, the cerebral edema formation, and the brain's immune responses were examined. The outcomes showed that PU NP-contained gelatin attenuated the brain edema, suppressed the gene expression levels of pro-inflammatory M1 biomarkers (e.g., IL-1β level to be about 25%), elevated the gene expression levels of anti-inflammatory M2 biomarkers (e.g., IL-10 level to be about 220%), and reduced the activation of inflammatory cells in the implanted site, compared with the conventional gelatin. Moreover, PU NP-contained gelatin increased the gene expression level of neurotrophic factor BDNF by nearly 3-folds. We concluded that the PU NP-contained hemostatic agents are anti-inflammatory with neuroprotective potential in vivo. This new hemostatic agent will be useful for surgery involving vulnerable tissue or organ (e.g., CNS) and also for diseases such as stroke, traumatic brain injury, and neurodegenerative diseases.