Comparison between different isoelectric points of biodegradable gelatin sponges incorporating ß-tricalcium phosphate and recombinant human fibroblast growth factor-2 for ridge augmentation: A preclinical study of saddle-type defects in dogs.

BACKGROUND AND OBJECTIVE: It is well known that recombinant human fibroblast growth factor-2 (rhFGF-2) signaling plays an important role in tissue repair and regeneration. rhFGF-2 strongly binds to acidic gelatin via ionic linkages and is gradually released upon gelatin decomposition. On the other hand, the linkage between rhFGF-2 and basic gelatin is so weak that most rhFGF-2 is rapidly released from basic gelatin by simple desorption. Gelatin/ß-tricalcium phosphate (ß-TCP) sponges, which comprise 50 wt% gelatin and 50 wt% ß-TCP in a cross-linked structure, can release rhFGF-2 gradually owing to their electrical features. In a previous study, we reported that new bone height in the test group using rhFGF-2 with acidic gelatin/ß-TCP sponges was significantly greater than that in the control group using acidic gelatin/ß-TCP sponges alone in a ridge augmentation model in dogs. However, whether these results depend on controlled release by the gelatin/ß-TCP sponges remains controversial. In this study, we evaluated the effects of controlled release by comparing acidic and basic gelatin/ß-TCP sponges with different isoelectric points (IEP) on ridge augmentation in dogs. MATERIALS AND METHODS: Twelve weeks after extraction of the maxillary second and third incisors of six dogs, critically sized saddle-type defects (8 mm length × 4 mm depth) were surgically created bilaterally 2 mm from the mesial side of the canine. Acidic gelatin/ß-TCP sponges (IEP 5.0) soaked with 0.3% rhFGF-2 were applied to the defect in the acidic group, whereas basic gelatin/ß-TCP sponges (IEP 9.0) soaked with 0.3% rhFGF-2 were applied to the defect in the basic group. Twelve weeks after surgery, biopsy specimens were obtained and subjected to microcomputed tomography (micro-CT) and histological analyses. RESULTS: New bone area detected by micro-CT analysis was significantly smaller in the basic group than in the acidic group. New bone height calculated by histologic sections was significantly lower in the basic group than in the acidic group. The total tissue height was lower in the basic group than in the acidic group. However, the differences between both sites were not significant. CONCLUSIONS: These findings suggest that in ridge augmentation of saddle-type defects, controlled release of rhFGF-2 induces notably more alveolar bone formation than does short-term application of rhFGF-2.

Evaluation of the safety and efficacy of a new hemostatic powder using a quantitative surface bleeding severity scale.

AIMS OF THE STUDY: The safety and efficacy of a hemostatic powder (HP) versus a control agent, absorbable gelatin sponge and thrombin (G + T), were assessed, using a validated, quantitative bleeding severity scale. METHODS: Subjects were randomized to receive HP (256 subjects) or G + T (132 subjects) for treatment of minimal, mild, or moderate bleeding at 20 investigational sites. The primary efficacy endpoint was non-inferiority of HP relative to G + T for success at achieving hemostasis within 6 minutes. Secondary endpoints in rank order included: superiority of HP relative to G + T in mean preparation time; non-inferiority of HP relative to G + T for achieving hemostasis within 3 min; superiority of HP relative to G + T for achieving hemostasis within 6 min; and superiority of HP relative to G + T for success for achieving hemostasis within 3 min. RESULTS: A total of 388 subjects were included in the primary efficacy analysis. At 6 min, hemostasis was achieved in 93.0% (238/256) of the HP group compared to 77.3% (102/132) of the G + T group (non-inferiority P < 0.0001, superiority P < 0.0001). All secondary endpoints were met. Complications were comparable between treatment groups. CONCLUSIONS: HP had superior rates of hemostasis, shorter preparation time, and a similar safety profile compared to G + T in this prospective, randomized trial using quantitative bleeding severity criteria.

In vitro analysis of growth patterns of invasive fungal species on commonly used endonasal hemostatic agents.

OBJECTIVE: Previous studies have not examined the potential role of endonasal hemostatic agents in facilitating growth of fungal species. We aim to determine the possibility of these to serve as a nutrient source for fungal growth. METHODS: Cultures of Aspergillus, Fusarium, and Mucor were harvested and placed in solution in sterile saline at standardized high and low concentrations. Thrombin gelatin matrix, carboxyl methylcelluose, and potato starch derivative agents were prepared following manufacturer instructions and applied to two separate Petri dishes per agent. Each substrate was then inoculated with either high or low concentrations of fungal species. Negative and positive control plates with each organism were included. Dishes were sealed, incubated, and examined daily for fourteen days for microscopic and macroscopic growth. RESULTS: Thrombin gelatin matrix was relatively resilient to growth, although Fusarium growth was noted on all packing material by day three. Carboxyl methylcellulose also supported growth of high-concentration Mucor appreciated on day five. The potato starch derivative supported fulminant growth of all fungal species. CONCLUSIONS: Endonasal hemostatic agents may be nutrient sources that facilitate growth of fungal species. This may be a consideration in a surgeon's decision to use a hemostatic agent. Prompt initial post-operative debridement may be warranted in select patients. Our findings serve as a model for further testing of fungal growth on other hemostatic materials. Future studies are needed to confirm the clinical significance of these findings in vivo.

The effects of different packing materials on healing and hearing after trauma to middle ear mucosa, an experimental study in rats.

PURPOSE: To compare the performance of Spongostan, Otopore, Spongostan soaked with dexamethasone and Spongostan soaked with Hyaluronic acid (HA) as middle ear packing material after mucosal trauma. METHODS: Twenty rats were divided into 4 groups. In control group (group 1), the middle ear cavities of animals were bilaterally packed with Spongostan; in group 2, with Otopore; in group 3, with Spongostan soaked with dexamethasone; and in group 4, with Spongostan soaked with HA. Auditory brainstem responses (ABRs) were performed preoperatively and 1 and 6 weeks postoperatively. Histological analyses were performed to evaluate the inflammatory reaction and wound healing in the middle ear cavity. RESULTS: ABR recordings demonstrate that threshold level changes from baseline were minor in Otopore and Spongostan soaked with dexamethasone packed ears. Threshold levels were higher in the Spongostan and Spongostan soaked with HA packed ears compared with both Otopore and Spongostan soaked with dexamethasone packed ears. Histological analyses showed that Spongostan caused inflammation more intense than Otopore and Spongostan soaked with dexamethasone. Residual material at postoperative week 6, new bone formation and adhesion were common in the Spongostan group compared with other groups. Fibrosis was more common in Spongostan group compared with other groups but the difference was not significant. CONCLUSION: Otopore appears to be safe and effective for use in otologic surgery. The inflammation, adhesion and new bone formation decreased when Spongostan was used with steroid or HA, when compared to Spongostan alone.

Comparing Gelfoam vs fat as a sealing material in stapedotomy: A prospective double-blind randomised clinical trial.

OBJECTIVES: One research aspect of stapes surgery is various materials that are used to seal the oval window. Several materials are used to seal the oval window, for example adipose tissue, perichondrium, vein graft, gelatin sponge (Gelfoam), blood clot and soft connective tissue. Up to now, there has been no randomised clinical trial that has evaluated the effects of different types of sealing material on hearing outcomes after stapedotomy. Hence, the present study aimed to find out which of these materials; fat or Gelfoam was associated with better hearing outcome, when used as a sealing material. DESIGN: This prospective, double-blind, randomised clinical trial was carried out on ears that had undergone stapedotomy. SETTING: Dastgheib Hospital affiliated to Shiraz University of Medical Sciences, a referral otology centre in southern Iran. PARTICIPANTS: A total of 176 primary stapedotomies were analysed. Fat harvested from the ear lobule was used in 86 ears and Gelfoam in 90 ears. MAIN OUTCOME MEASURES: Preoperative and postoperative pure tone audiometric data and incidence of sensorineural hearing loss were evaluated. RESULTS: Total of 90.7% of all ears in the fat group and 87.8% of ears in Gelfoam group achieved postoperative air-bone gap (ABG) within 20 dB, and this difference was not significant. There was no case of sensorineural hearing loss (defined as 10 dB or more reduction in BC threshold) in both groups in mean frequencies of 0.5-3 kHz. There were 9 cases of sensorineural hearing loss at 4 kHz in the fat group vs 4 in the Gelfoam group. The occurrence of sensorineural hearing loss in different frequencies was not significant between the two groups (P > 0.05). In addition, there was no case of dead ear in either group. CONCLUSIONS: We found similarity between hearing outcome in the Gelfoam and fat as sealing materials in stapedotomy. We believe that the first limitation of this study was the short-term follow-up in stapedotomy. The other issue is that one has to be cautious when using our result, which might not be applicable in larger fenestra stapedectomy.

The Effect of PRP-enriched Gelfoam on Chronic Tympanic Membrane Perforation: A Double-blind Randomized Clinical Trial.

OBJECTIVE: To evaluate the effect of PRP-enriched gelfoam on the healing of chronic TM perforation in comparison with gelfoam alone. METHODS: In this double-blind randomized clinical trial Patients with chronic tympanic membrane were randomly allocated to two groups; intervention group underwent tympanoplasty with platelet rich plasma (PRP)- enriched gel foams and control group underwent operation with conventional gel foams alone. Patients information was recorded 4 and 12 months after surgery. RESULTS: Eventually 24 patients (12 males and 12 females) with a mean age of 43.33 ± 12.34 years in intervention and 41.33 ± 10.02 years in control group underwent analysis (p = 0.667). Complete TM healing was seen in 8 (66.67%) patients in intervention group and 3 (25%) patients in control group three months after intervention (p = 0.031, OR = 5.98). CONCLUSION: Addition of PRP to conventional gelfoams used in TM perforation repair increases the complete healing rate of TM perforation with less morbidity and complications.

Safety and Efficacy of Chitosan-Dextran Hydrogel in the Middle Ear in an Animal Model.

OBJECTIVES: To investigate the efficacy of chitosan-dextran hydrogel (CDH) in preventing postoperative adhesions between the tympanic membrane (TM) and intratympanic structures, and to evaluate its ototoxicity in an animal study. METHODS: In the first step, ototoxicity was evaluated with 7 male albino guinea pigs (GPs) via auditory brainstem responses (ABR) before and 4 weeks after unilateral intratympanic injection of CDH and saline solution contralaterally. In the second step, 12 GPs underwent bilateral ear surgery. The middle ear (ME) mucosa was abraded, and the cavity was filled with CDH on one side and packed with Gelfoam on the contralateral side. A control group of 6 GPs underwent the same procedure except that no material was applied in the ME. The animals were euthanized at the end of the 7th week, and otomicroscopic findings were noted and the temporal bones harvested for the histologic examination. The findings were scored and compared. RESULTS: There was no statistically significant difference between the pre- and postoperative ABR thresholds. In the otomicroscopic findings, the most prominent difference between the two groups was the presence of retraction of the TM in the Gelfoam group. The histopathologic findings revealed a higher degree of inflammation in the Gelfoam group compared with the CDH group. CONCLUSION: This study demonstrated that CDH has no ototoxic effects in GPs. Its use as an ME packing material revealed significantly less TM retraction and inflammatory reaction compared with Gelfoam.

Improved bleeding scores using Gelfoam(®) Powder with incremental concentrations of bovine thrombin in a swine liver lesion model.

Topical hemostatic agents are used intra-operatively to prevent uncontrolled bleeding. Gelfoam(®) Powder contains a hemostatic agent prepared from purified pork skin gelatin, the efficacy of which is increased when combined with thrombin. However, the effect of increasing concentrations of thrombin on resultant hemostasis is not known. This study sought to evaluate the ability of various concentrations of thrombin in combination with Gelfoam Powder to control bleeding using a swine liver lesion model. Ten pigs underwent a midline laparotomy. Circular lesions were created in the left medial, right medial, and left lateral lobes; six lesions per lobe. Gelfoam Powder was hydrated with Thrombin-JMI(®) diluted to 250, 375, and 770 IU/mL. Each concentration was applied to two lesion sites per lobe. Bleeding scores were measured at 3, 6, 9, and 12 min using a 6-point system; comparison of bleeding scores was performed using ANOVA with the post hoc Tukey test. The bleeding scores with thrombin concentrations at 770 IU/mL were significantly lower than at 250 and 375 IU/mL at all four time points. The percentage of biopsies with a clinically acceptable bleeding score rose from 37.9, 46.6, and 71.2 % at 3 min to 55.2, 69.0, and 88.1 % at 12 min in the 250, 375, and 770 IU/mL thrombin groups, respectively. The study showed that the hemostatic response to thrombin was dose-related: using higher concentrations of thrombin with Gelfoam Powder yielded improved hemostasis, as determined by lower bleeding scores.

Biocompatibility and efficacy of collagen/gelatin sponge scaffold with sustained release of basic fibroblast growth factor on vocal fold fibroblasts in 3-dimensional culture.

OBJECTIVE: Treatment of vocal fold scarring remains challenging. We have previously reported the therapeutic effects of local injection of basic fibroblast growth factor (bFGF) in animal models and humans. A novel collagen/gelatin sponge (CGS) is capable of sustained release of bFGF, which compensates for its quick absorption in vivo, avoiding multiple injections. This study aimed to evaluate the biocompatibility and efficacy of the CGS in rat vocal fold fibroblasts prior to human trials. METHODS: Fibroblasts extracted from Sprague-Dawley rat vocal folds were seeded onto a CGS and then cultivated with bFGF at concentrations of 0, 10, and 100 ng/mL. Vocal fold fibroblast morphology, adhesion, proliferation, and gene expression were measured under these 3-dimensional conditions. RESULTS: Cells adhered to the CGS from day 1. Although no significant differences in cell morphology were detected, cell proliferation was accelerated by bFGF administration. Expression of endogenous bFGF and hepatocyte growth factor was significantly up-regulated at 10 ng/mL bFGF. The expression of procollagen I and procollagen III was significantly suppressed, whereas HAS-1 and HAS-2 were up-regulated at 10 and 100 ng/mL bFGF. CONCLUSION: The collagen/gelatin sponge is biocompatible with vocal fold fibroblasts and may be useful as a bFGF drug delivery system for the treatment of scarred vocal folds.

[Influence of the gelatin-alginate matrixes with calcium lactate in plasma coagulation system after implantation in soft tissues]. / Wplyw matryc zelatynowo-alginianowych z mleczanem wapnia na osoczowy uklad krzepniecia po implantacji w tkanki miekkie.

BACKGROUND: Bioresorbable porous substrates from copolymers have their application in tissue engineering to culture tissues in vitro. The advantage of polymers is the production of thermoplastic elements and their ability to biodegrade in a living body. Gelatin, collagen, alginates are part of dressings used for topical administration of the drug. Research was undertaken to achieve a porous gelatin-alginate matrix which could be used in therapy as among others, a carrier for a drug. OBJECTIVES: Evaluation of the impact of modified gelatin-alginate matrix on activation of plasma coagulation in vivo. MATERIAL AND METHODS: Gelatin-alginate matrix cross-linked with calcium ions was implanted in the muscle tissue of a rat. The control group constituted animals not implanted with material, but they passed the operating procedure. Blood samples of plasma coagulation test and control group were collected after 1, 2, 3, 5, 7, 10, 14 days of the procedure. RESULTS: Prolongation of APTT and shortening of PT and TT with the unchanged values of fibrinogen and the count of platelet cells was observed till the 5th day on the basis of the obtained results. Prolongation of APTT with the unchanged values of the remaining parameters of the coagulation system was observed after 7, 10 and 14 days with unchanged values of PT and TT coagulation. CONCLUSIONS: The matrix gelatin-alginate with calcium ions in the biological environment undergoes biodegradation in soft tissues. This process in the initial period influences the activation of the coagulation within the intrinsic and extrinsic system. From the 5th to 14th day the activation of coagulation was observed only in the intrinsic system.

[Influence of gelatin-alginian matrixes on morphological and functional changes of blood leukocytes]. / Wplyw matryc zelatynowo-alginianowych na zmiany morfologiczne i czynnosciowe leukocytów krwi.

BACKGROUND: Knowledge of the relation of biomaterials and living tissues constitutes necessary information which should be used when composing a set of optimal carriers, e.g. for drugs or preparations supporting blood clotting. OBJECTIVES: This paper presents an assessment of the influence of contact of gelatin-alginian matrixes with blood on leukocyte reactivity: the ability of mononuclear cells (lymphocytes and monocytes) to create a radial segmentation of nuclei--RS (the morphological change), and the ability of leukocytes to phagocytosis of yeast Saccharomyces cerevisiae cells and to produce active oxygen derivatives (functional changes). MATERIAL AND METHODS: After having contact with the matrixes, the test of induced and spontaneous RS, the phagocytic test and nitroblue tetrazolium reduction test for blood leukocytes were performed. RESULTS: The obtained results showed a decrease in the ability of mononuclear cells to form RS and in the ability of granulocytes to reduce nitroblue tetrazolium--NBT, but an increase in their phagocytic activity. CONCLUSIONS: Temporary contact of gelatin-alginian matrixes with blood did not cause any morphological changes in the leukocytes. However, changes of their reactivity were observed.

Autologous mesenchymal stem cells loaded in Gelfoam(®) for structural bone allograft healing in rabbits.

This study was designed to evaluate the effect of autologous bone marrow mesenchymal stem cells (MSCs) seeded into Gelfoam® on structural bone allograft healing. Thirty New Zealand white rabbits were divided into two groups. Segmental bone defect was created on diaphysis of the femur, and the defect was reconstructed with structural bone allograft. In experimental group, structural allograft was wrapped around by Gelfoam® containing autologous MSCs, whereas cells were not included in control group. At 4, 8, 12 weeks, the femur of rabbits underwent radiographic and histologic evaluation for bony union. Bone morphogenic protein-2 (BMP-2), BMP-4, BMP-7, vascular endothelial growth factor (VEGF), and receptor activator of nuclear factor-kappa B ligand (RANKL) were measured within the grafted periosteal tissue. Bony union was not achieved in both groups at 4 and 8 weeks. At 12 weeks, three out of five femurs in experimental group were united, but one out of five in control group was united. Mean Taira scores were significantly different between two groups. The expression of BMP-2 was significantly higher at 4, 8 weeks, the expressions of BMP-4 and BMP-7 were significantly higher at 8 and 12 weeks, and the expression of VEGF and RANKL were significantly higher at all time points in experimental group. Incorporation of the structural bone allograft could be enhanced if allograft is covered with Gelfoam® containing autologous MSCs. MSCs have influence on not only bone formation, but neo-angiogenesis, and bone resorption.

A Universal Gelfoam 3-D Histoculture Method to Establish Patient-derived Cancer Cells (3D-PDCC) Without Fibroblasts from Patient-derived Xenografts.

BACKGROUND/AIM: The direct placement of patient tumors in 2-D culture on plastic or glass surfaces has inhibited the establishment of patient-derived cancer cells (PDCCs). The aim of the present study was to develop universal and efficient methods to prepare PDCCs. MATERIALS AND METHODS: Fragments of patient-derived xenograft (PDX) tumors established form colon cancer liver metastasis (1 mm3) were placed on Gelfoam and cultured in DMEM. RESULTS: PDX tumor fragments were cultured on Gelfoam. Cancer cells migrated from the explant and formed distinct 3-D structures in the Gelfoam. Each of the three PDCCs showed a distinct morphology. The cultures were essentially all cancer cells without fibroblasts, the opposite of what usually occurs in 2-D culture on plastic or glass. Gelfoam cultures could be readily passaged from one Gelfoam cube to anothers suggesting indefinite culture potential. CONCLUSION: A potentially universal method to establish PDCC using PDX tumors and 3-D Gelfoam histoculture was developed.

Acute in-vivo evaluation of bleeding with Gelfoam plus saline and Gelfoam plus human thrombin using a liver square lesion model in swine.

BACKGROUND: Management of post-operative bleeding has historically used topical bovine thrombin. However, possible harm through activation of coagulation inhibitors has encouraged investigation with other hemostatic agents. This study utilized a novel ordinal bleeding model to test whether a Gelfoam + human thrombin solution is superior at controlling bleeding when compared to Gelfoam + saline solution at different time intervals. STUDY DESIGN: Four swine underwent open laparotomy after receiving unfractionated heparin. Twenty open liver biopsies were performed in each swine; ten biopsies treated with Gelfoam + human thrombin solution and 10 biopsies treated with Gelfoam + saline solution. Three, 6 min, and 12 min after the procedure, bleeding was objectively graded by a four-point model. RESULTS: There was a significant (P < 0.017), treatment effect on each success/failure outcome (success = bleeding score 1) at 3 (P < 0.001), 6 (P < 0.001), and 12 (P = 0.003) min, based on a 2 x 2 Fisher's exact test. Similarly, there was a significant treatment effect on each success/failure outcome and four-point bleeding score based on a multiple logistic regression analysis controlling for pig, lesion weight, and initial bleeding taking into consideration repeated measures at three time points. CONCLUSIONS: The results demonstrate a superior treatment effect for control of bleeding using human thrombin compared to a saline solution. Future studies should compare bovine thrombin versus human thrombins ability to control bleeding as well as the hazard of each in activating coagulation inhibitors.

Histologic analysis of the effects of three different support materials within rat middle ear.

OBJECTIVE: To investigate histologic changes in the mucosa of rat middle ear after implantation of three different support materials. STUDY DESIGN: A prospective, controlled animal study. SUBJECTS AND METHODS: Three types of absorbable materials were implanted into the middle ear cavity of rats: (1) Gelfoam (purified gelatin) (Pharmacia & Upjohn Company, New York, NY), (2) Sepragel (viscoelastic gel composed of cross-linked polymers of hyaluronan) (GENZYME Corp, Ridgefield, NJ), and (3) Nasopore (a biodegradable/fragmentable, synthetic polyurethane foam) (Polyganics, Groningen, The Netherlands). Rats were sacrificed after 3 and 20 days to ascertain early and late histologic changes. The bulla of each rat was excised and prepared for microscopic examination. The histologic changes were evaluated by observation of the middle ear cavity and mucosa in terms of polymorphonuclear leucocytes (PMNL), macrophages, giant cells, fibroblasts and other cells, fibrosis, and remnant materials. RESULTS: The histologic appearance of gelfoam-treated middle ears was characterized by more severe acute inflammation in the short-term and prominent fibrosis in the long-term in comparison with sepragel- and nasopore-treated groups. Nasopore appeared to be prone to remnant formation and reorganization by means of fibroblastic activity. CONCLUSION: Compared with gelfoam, both sepragel and nasopore caused less histologic alterations.

The role of FloSeal in reducing epidural fibrosis in a rat laminectomy model.

BACKGROUND AND PURPOSE: An increased amount of fibrosis formed after lumbar surgery may be the underlying cause of the failed back surgery syndrome in most cases. Various materials have been used to prevent epidural fibrosis, but only limited success has been achieved. In this study, the authors investigated the effect of FloSeal (a gelatine-containing thrombin-based haemostatic agent) on spinal epidural fibrosis in a rat laminectomy model. MATERIAL AND METHODS: Sixteen Wistar rats underwent laminectomy at L4 and L5 levels. In 8 rats, 0.5 mL of FloSeal was locally applied to the laminectomy site. The laminectomy site was irrigated with saline in the control group of 8 other rats. The rats were sacrificed four weeks later. Each specimen was examined for density of fibrosis, and both fibroblast and inflammatory cell density. RESULTS: Epidural fibrosis density differed significantly between the FloSeal group and the control group. Evaluation of the fibroblast density and the inflammatory cell density showed a statistically significant difference between the FloSeal group and the control group. CONCLUSION: Application of FloSeal at a laminectomy site may be useful to decrease adhesion at the interface between the dura mater and epidural fibrosis.

[The study and clinical application of absorbable hemostatic agent].

This paper reviews the mechanisms and properties of different absorbable hemostatic agents. The development tendency of absorbable hemostatic agent is forecasted. Its' qualities of being useful to surgeons are introduced and are embodied in surgeon's comprehending of the hemostatic characteristic of absorbable hemostatic agents as well as in their clinical use of such agents accurately. At the same time, the researchers in pursuit of the medical materials can work with reference to the data herein presented.

Polydopamine reinforced hemostasis of a graphene oxide sponge via enhanced platelet stimulation.

Graphene oxide (GO) is a promising hemostatic material because of its platelet stimulatory activity. However, our previous studies on cross-linked graphene sponges demonstrated that those sponges lost the GO function of platelet stimulation due to the pristine GO was reduced under the harsh reaction conditions. Accordingly, a mild cross-linking strategy is expected to preserve the oxygen-containing groups to further increase the hemostatic performance of the sponges. Here, we present a polydopamine (PDA) cross-linked GO sponge (DCGO) by using mild and facile wet chemistry. The obtained DCGO possessed a high surface charge (-31.3 ± 0.3 mV) and showed strong platelet stimulation. Moreover, this method strengthened the mechanical properties of the DCGO, which supported 350 times its own weight without deformation, thus ensuring its absorbability. For the synergy of platelet stimulation and physical absorption, DCGO achieved outstanding hemostatic performance. Bleeding stopped within 105 ± 15 s, which was 165 s faster than that of the un-cross-linked GO aerogel and 96 s faster than that of the cross-linked graphene sponge (CGS). The DCGO combines the advantages of both PDA and GO, thus supplying a new material and method for the field of trauma hemostasis.

The effect of anti-adhesive packing agents in the middle ear of guinea pig.

BACKGROUND & OBJECTIVE: The presence of adhesions after middle ear surgery is not uncommon. Fibrosis can cause conductive hearing loss and it contributes to retraction of the tympanic membrane in the post-surgery patient. The purpose of this study was to evaluate the anti-adhesive effect of Seprafilm and MeroGel in the abraded mucosa of a guinea pig's middle ear. MATERIALS AND METHODS: Fifteen pathogen-free adult male albino guinea pigs weighing 250-300g each were used. Under an aseptic condition, the middle ear mucosa was abraded using a pick through a myringotomy incision. Seprafilm, MeroGel and Gelfoam, respectively, were then packed into guinea pigs' middle ear cavities. Auditory brainstem responses (ABRs) were assessed preoperatively and 3 weeks after operation. RESULTS: The ABR results at postoperative week 3 showed no statistically significant difference for the myringotomy and postpacking, except for the MeroGel packing. However, there was no significant threshold on the 6 weeks' postoperative ABR. The Gelfoam group demonstrated extensive fibrosis and adhesion within the bulla cavity. The Seprafilm and MeroGel groups showed no adhesion in the middle ear cleft after abrasion of the mucosa. CONCLUSION: From these results, we suggest the use of Seprafilm and MeroGel to improve the results of otosurgery.

Effects of Meropack in the middle meatus after functional endoscopic sinus surgery in children with chronic sinusitis.

OBJECTIVES: The aim of the study was to evaluate the effects and morbidities of Meropack, an absorbable hyaluronic acid packing material, placed in the middle meatus after endoscopic sinus surgery in children with chronic sinusitis. METHODS: Sixty consecutive children with similar degrees of bilateral chronic sinusitis were enrolled in the study. Meropack was randomly inserted into one side of the middle meatus, while the opposite sinus was not packed after functional endoscopic sinus surgery. Patients were investigated 3, 8, and 12 weeks after surgery. The effects and morbidities of nasal dressings in the middle meatus were evaluated with respect to six distinct parameters: blood loss during surgery, postoperative hemorrhage, synechiae, granulation tissue, infection, and patency of the maxillary sinus ostia. RESULTS: Mean blood loss of packed and unpacked sinuses did not significantly differ (p > 0.05). Twenty-nine (15 packed, 14 unpacked) of the 120 sinuses underwent resection of the lateral wall of concha bullosa. Four of 14 unpacked sinuses had postoperative hemorrhaging, while the 15 packed sinuses did not (p < 0.05). The mean synechiae scores at the first follow-up visit for the Meropack filled and unpacked sinuses differed significantly (p < 0.05). For the 8- and 12-week follow-up visits, severity of adhesions, granulation tissue formation, infection rate, and patency of the maxillary sinus ostia did not differ significantly between the Meropack filled sinuses and the unpacked sinuses (p > 0.05 for all). CONCLUSION: Meropack dressings effectively prevented postoperative hemorrhage, but did not significantly reduced synechiae after endoscopic sinus surgery. Therefore, we recommend that Meropack packing is not necessary for routine use following pediatric functional endoscopic sinus surgery (FESS). However, it should be reserved for children who are predisposed to develop postoperative hemorrhages or adhesions, such as resection of the concha bullosa, traumatic surgery with the creation of large raw surfaces on the middle turbinate, and revision surgery with preexisting adhesions.