Evaluation of the Effectiveness of Peritoneal Adhesion Prevention Devices in a Rat Model.

BACKGROUND: Abdominal operations are followed by adhesions, a prevalent cause of abdominal pain, and the most frequent cause for bowel obstruction and secondary female infertility. This rat study addresses adhesion prevention capability of Adept(®), Interceed(®), Seprafilm(®), and a novel device, 4DryField(®) PH which is provided as powder and generates its effect as gel. METHODS: Sixty-eight male Lewis rats had cecal abrasion and creation of an equally sized abdominal wall defect, and were grouped randomly: A control group without treatment (n=10); two groups treated with 4DryField(®) PH using premixed gel (n=15) or in-situ gel technique (n=16); one group each was treated with Seprafilm(®) (n=8), Interceed(®) (n=9), or Adept(®) (n=10). Sacrifice was on day 7 to evaluate incidence, quality, and quantity of adhesions, as expressed via adhesion reduction rate (AR). Histologic specimens were evaluated. Statistical analyses used ANOVA and unpaired t-tests. RESULTS: 4DryField(®) PH significantly reduced incidence and severity of adhesions both as premixed gel (AR: 85.2%) and as in-situ made gel (AR: 100%), a comparison between these two application techniques showed no differences in efficacy. Seprafilm(®) did not reduce incidence but severity of adhesions significantly (AR: 53.5%). With Interceed(®) (AR: 3.7%) and Adept(®) (AR: 16.1%) no significant adhesion-reduction was achieved. Except for inflammatory response with Interceed(®), histopathology showed good tissue compatibility of all other devices. CONCLUSION: 4DryField(®) PH and Seprafilm(®) showed significant adhesion prevention capabilities. 4DryField(®) PH achieved the highest adhesion prevention effectiveness without restrictions concerning mode of application and compatibility and, thus, is a promising strategy to prevent abdominal adhesions.

Impairment of the Peritoneal Surface as a Decisive Factor for Intestinal Adhesions in Intraperitoneal Onlay Mesh Surgery - Introducing a New Rat Model.

BACKGROUND: Meshes implanted intraperitoneally are known to cause adhesions potentially resulting in complications such as chronic pain, enterocutaneous fistula, or mesh infection. This study introduces a model for investigation of intestine-to-mesh adhesions and evaluates as to whether missing of visceral peritoneum is causative. METHODS: In 18 rats, rectangular 1.5 x 2 cm patches of an uncoated polypropylene mesh (Ultrapro(®)) were sewn to the inner abdominal wall next to the cecum. Additionally, a meso-suture ensured contact between cecum and mesh. Rats were assigned to 2 groups: in 8 rats the peritoneum was left intact, in 10 the cecum was depleted from peritoneum with abrasion. Sacrifice was on day 7. Macroscopic evaluation used two adhesion scores. Specimens were evaluated microscopically, statistical analyses employed student's t-test. RESULTS: On day 7, rats with mesh implantation combined with locally de-peritonealization by cecal abrasion mostly showed severe cecum-to-mesh agglutination (mean Lauder score 92%, mean total Hoffmann score 90%), whereas meshes of most animals without cecal abrasion only had some coverage with intraabdominal fat (33%, 24%; p = 0.0002). Histological work-up showed adequate wall ingrowth of mesh in all rats. In animals with cecal abrasion, meshes were mostly adhesive with cecal wall. However, when the peritoneum of cecum was unimpaired, abdominal wall above the mesh as well as cecum usually revealed sub-peritoneal tissue and a mono-layer cell coverage as seen in normal peritoneum. CONCLUSION: This study introduces a model mimicking a clinical situation of e.g. hernia repair by intraperitoneally implanted meshes when mesh has contact with normal and with de-peritonealized intestine. The model might be useful for testing mesh types and coatings as well as other devices for their efficacy in adhesion prevention. The high adhesion scores of rats with local de-peritonealization compared with the low scores of animals with intact peritoneum indicate that the integrity of intestinal peritoneum is a decisive factor for adhesion formation.

Childhood adversities: Social support, premorbid functioning and social outcome in first-episode psychosis and a matched case-control group.

OBJECTIVE: The establishment of childhood adversities as risk factors for non-affective psychosis has derived a need to consider alternative interpretations of several psychosis-related factors. This paper sought to examine premorbid adjustment trajectories and social outcome factors in relation to childhood adversities. Perceived support has been found to decrease the risk of post-traumatic stress disorder, and we wished to compare perceived support in people with first-episode psychosis to non-clinical control persons and explore its relation to childhood adversities. METHOD: Every individual presenting with a non-affective first-episode psychosis (F20-29, except F21) in Region Zealand over a 2-year period was approached for participation and the 101 consenting participants were matched to 101 people with no psychiatric disorders. Comprehensive demographic data were collected. Assessment instruments included the Premorbid Assessment Scale, the Global Assessment of Functioning scale and the Childhood Trauma Questionnaire. The latter represented the childhood adversities in addition to parental separation and institutionalization. RESULTS: There were no associations between number of childhood adversities and different social or academic premorbid trajectories. Those with more adversities had lower global functioning the year prior to treatment start and reported lower rates of perceived support during childhood along with less current face-to-face contact with family members. Lack of peer support remained a significant predictor of psychosis when adversities were adjusted for; peer support diminished the risk of psychosis caused by childhood adversities by 10%. CONCLUSION: Childhood adversities may not predict specific premorbid trajectories, but have an effect on global functioning when the psychosis has begun. Perceived support, especially from peers, may be important in the development of psychosis, and those with more adversities may represent a vulnerable subgroup who need more assistance to increase and maintain supportive networks.