Study of Pain Perception Between Males and Females Following Laparoscopic Cholecystectomy
Condition: Cholecystitis, Acute; Cholecystitis, Chronic
MeSH terms: Cholecystitis; Acalculous Cholecystitis; Cholecystitis, Acute
Study type: Observational

Summary: 
      This study looks at the differences in inflammatory mediators in gallbladder tissue between
      males and females and the possibility that these differences contribute to a higher
      perception of post-operative pain in females following laparoscopic cholecystectomy.
    

Detailed description: 
      A patient's gender is a strong and significant predictor for substantial differences in
      clinical outcomes such as postoperative pain, analgesic use, and surgical complications
      (gangrenous gallbladder, empyema of the gallbladder, gallbladder perforation, and conversion
      to open surgery) following laparoscopic cholecystectomy (Bingener et al., 2002; Bingener et
      al., 2003; Uchiyama et al., 2006). Although females present for laparoscopic cholecystectomy
      more frequently (76% of the cases); the prevalence of surgical complications during
      cholecystectomy is higher in men, most frequently because of inflammation or deterioration of
      the gallbladder (Bingener et al., 2002; Bingener et al., 2003; Stefanidis et al., 2006).
      Post-operatively, however, females report significantly greater pain scores and require
      larger amounts of analgesics (Uchiyama et al., 2006), suggesting that although surgeries are
      completed with fewer problems, females still report more post-operative pain. Sex-related
      differences in pain thresholds and tolerance to thermal, pressure, and electrical stimuli in
      experimental pain models indicate that pain differences are not solely due to psychosocial
      distinctions between the sexes (Riley et al., 1998).

      There are multiple physiological differences between males and females; however, considerable
      evidence implicates estrogenic sex hormones as critical factors in sex-dependent differences
      in pain (see review by Fillingim and Ness, 2000). It is possible that estrogens alter
      inflammatory mediator profiles in the gallbladder, which subsequently increase sensitization
      of visceral neurons innervating the gallbladder, resulting in increased pain in females. The
      first portion of this study will extend the association of patient sex with clinical outcomes
      to determine whether circulating and/or local estrogen levels correlate with differences in
      peri-operative morbidity, including intra-operative complications, conversion to open
      cholecystectomy, postoperative pain, inadequate wound healing, intra-abdominal infection,
      disability and mortality.

      Previous studies have demonstrated that the cytokines TNFalpha and IL-1beta alter the
      sensitivity of sensory neurons and increase nociception (Opree and Kress, 2000). To determine
      whether estrogen levels alter the profile of inflammatory mediators within the gallbladder
      and result in an increase in nociceptive thresholds in females, we will correlate circulating
      and/or local levels of estrogens with the amount of inflammatory mediators present within
      laparoscopically excised gallbladder biopsies. Patients who meet the inclusion criteria will
      be recruited from University Hospital in San Antonio. Inflammatory mediators, including the
      cytokines IL-1beta, TNFalpha, IL-8, IL-6, IL-10, and IL-12p70 will be assayed from
      interstitial fluid of biopsies from the fundus and infundibulum of the gallbladder. Biopsies
      will be classified according to clinical assessment prior to surgery to control for expected
      differences in inflammatory mediators in acute versus chronic cholecystitis.

      The immediate effects of this research will be to clearly delineate whether estrogens are
      predictive of improved clinical outcomes following surgery and to determine whether these sex
      hormones correlate with altered production of inflammatory mediators in the gallbladder.
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Outpatient General Surgery patients indicated for Laparoscopic Cholecystectomy
      
Biospecimen description: 
      1 cm biopsies of the body and fundus of the excised gallbladder. Two 4ml blood samples
      collected for DNA analysis with future studies.
    
Keywords: Pain, Cholecystectomy, Cytokines, Sex Differences