Chitosan Pad, Cellulose Membrane, or Gelatin Sponge for Peridural Bleeding: An Efficacy Study on a Lumbar Laminectomized Rat Model

Study DesignExperimental study in an animal model.PurposeThis study aims to evaluate the hemostatic properties of four common hemostatic materials including the chitosan clot pad, absorbable gelatin sponge, cellulose membrane, and gauze on peridural bleeding using a rat model.Overview of LiteratureIntraoperative bleeding during spinal surgery can lead to morbidities. Hemostatic materials have been developed, but the efficacy of these materials on peridural bleeding remains unclear.MethodsForty 8-week-old Sprague-Dawley rats were used in this study. Under adequate anesthesia, each rat was posteriorly dissected to their L5 and L6 spinous processes. Bleeding from muscles and soft tissue dissections was stopped before lumbar bone cutting. Immediately after the L5–L6 laminae were cut and removed, the rats were randomly allocated to receive one of the abovementioned hemostatic materials. All hemostatic materials were placed over the raw surface of cut bone and dura and changed every 60 seconds. The procedure was stopped when there was no further bleeding. Time to staunching and amount of bleeding were recorded for statistical analysis.ResultsThe respective mean±standard deviation hemorrhage volume and time for the cellulose membrane, gelatin sponge, chitosan pad, and gauze were 1.19±0.44, 1.03±0.72, 0.96±0.57, and 1.98±0.62 mL, respectively, and 2.9±0.6, 2.1±0.6, 1.7±0.5, and 2.9±1.0 minutes, respectively. The overall bleeding volumes for the cellulose membrane, gelatin sponge, and chitosan pad were significantly lower than the overall bleeding volume for gauze.ConclusionsChitosan clot pads, gelatin sponges, and cellulose membranes have better hemostatic properties than gauze. The chitosan pad had the lowest average bleeding volume, followed by gelatin sponge and cellulose membrane

Interrater Reliability of the Postoperative Epidural Fibrosis Classification: A Histopathologic Study in the Rat Model

Study DesignAgreement study.PurposeTo validate the interrater reliability of the histopathological classification of the post-laminectomy epidural fibrosis in an animal model.Overview of LiteratureEpidural fibrosis is a common cause of failed back surgery syndrome. Many animal experiments have been developed to investigate the prevention of epidural fibrosis. One of the common outcome measurements is the epidural fibrous adherence grading, but the classification has not yet been validated.MethodsFive identical sets of histopathological digital files of L5-L6 laminectomized adult Sprague-Dawley rats, representing various degrees of postoperative epidural fibrous adherence were randomized and evaluated by five independent assessors masked to the study processes. Epidural fibrosis was rated as grade 0 (no fibrosis), grade 1 (thin fibrous band), grade 2 (continuous fibrous adherence for less than two-thirds of the laminectomy area), or grade 3 (large fibrotic tissue for more than two-thirds of the laminectomy area). A statistical analysis was performed.ResultsFour hundred slides were independently evaluated by each assessor. The percent agreement and intraclass correlation coefficient (ICC) between each pair of assessors varied from 73.5% to 81.3% and from 0.81 to 0.86, respectively. The overall ICC was 0.83 (95% confidence interval, 0.81-0.86).ConclusionsThe postoperative epidural fibrosis classification showed almost perfect agreement among the assessors. This classification can be used in research involving the histopathology of postoperative epidural fibrosis; for example, for the development of preventions of postoperative epidural fibrosis or treatment in an animal model