Standardization of surgeon-controlled variables: impact on outcome in patients with acute cholecystitis.

OBJECTIVE: To examine the effect of standardization of surgeon-controlled variables on patient outcome after cholecystectomy for two cohorts of patients with acute cholecystitis (AC). SUMMARY BACKGROUND DATA: Laparoscopic cholecystectomy (LC), when performed efficiently and safely, offers patients with AC a more rapid recovery and decreases the length of stay, thus reducing the health care utilization. Numerous studies have focused on the characteristics of patients with AC that may predict the conversion of LC to open cholecystectomy. However, analysis of these factors offers little insight for improving the outcome of patients with AC, because patient-controlled variables are difficult to influence. In the present study, treatment variables that were under the surgeon's control were standardized and the effects of these changes on the outcome of patients with AC were quantified. METHODS: Beginning in August 1997, a standardized treatment protocol was initiated for patients with suspected AC. LC was initiated as early as practical from the time of admission. All operations were performed in a specially equipped and staffed laparoscopic surgery suite, and all patients were supervised by one of two attending surgeons with a special interest in laparoscopic interventions. Two cohorts of patients with AC were retrospectively analyzed: 39 patients from the 12 months before initiation of this protocol (period 1) and 49 patients from the 12 months after its inception (period 2). Medical records were reviewed for demographic, perioperative, and outcome data. Surgical reports were reviewed to ascertain the reason for conversion and whether laparoscopic technical modifications were used. RESULTS: No significant difference was noted between the groups with regard to patient demographics, clinical presentation, or radiologic or laboratory parameters. After protocol initiation, patients received definitive treatment closer to the time of admission and had a greater percentage of laparoscopically completed cholecystectomies. Furthermore, the patients in period 2 had a significantly decreased postoperative length of stay and hospital charges than the earlier ones. Complications were infrequent and not significantly different between the groups. Two or more laparoscopic technical modifications were used in 95% of the successful LCs during period 2 versus 33.3% during period 1. CONCLUSIONS: By controlling when, where, and by whom LC for AC was performed, the authors have significantly improved the percentage of cholecystectomies that were completed laparoscopically. This has led to improved outcomes and lower hospital charges for patients with AC at this municipal hospital.

Preoperative abdominal ultrasound may be misleading in risk stratification for presence of common bile duct abnormalities.

BACKGROUND: Following the advent of laparoscopic cholecystectomy (LC), the preoperative predictors of common bile duct (CBD) abnormalities became more important in perioperative decision making. Preoperative transabdominal ultrasound (US) is used to assess the preoperative risks associated with CBD abnormalities. This study attempts to determine the sensitivity and specificity of US in determining CBD abnormalities in patients prior to LC. METHODS: US measurements of the CBD diameter and presence of stones were ascertained from radiology reports in 100 patients who had LC with a routine intraoperative cholangiogram (IOC). The same information was obtained from the patients' IOC. A supraduodenal CBD diameter of >8 mm was considered dilated. RESULTS: US demonstrated a sensitivity of 25% and a specificity of 70% for the detection of CBD dilatation compared to IOC. The sensitivity of US for predicting CBD dilatation was 55% when the IOC-derived diameter was >10 mm and 100% when it was >15 mm. The overall sensitivity of US for detection of stones was 10%; it improved to 17% in patients with a dilated CBD on US. CONCLUSIONS: Preoperative ultrasound is neither sensitive nor specific for detecting CBD dilatation or presence of stones. A negative preoperative US report may be misleading in risk stratification for the presence of these CBD abnormalities. In order to avoid missing any CBD pathology, we recommend the routine use of intraoperative cholangiography.

Studies in cranial suture biology: Part I. Increased immunoreactivity for TGF-beta isoforms (beta 1, beta 2, and beta 3) during rat cranial suture fusion.

The mechanisms involved in normal cranial suture development and fusion as well as the pathophysiology of craniosynostosis, a premature fusion of the cranial sutures, are not well understood. Transforming growth factor-beta isoforms (TGF-beta 1, beta 2, and beta 3) are abundant in bone and stimulate calvarial bone formation when injected locally in vivo. To gain insight into the role of these factors in normal growth and development of cranial sutures and the possible etiology of premature cranial suture fusion, we examined the temporal and spatial expression of TGF-beta isoforms during normal cranial suture development in the rat. In the Sprague-Dawley rat, only the posterior frontal cranial suture undergoes fusion between 12 and 22 days of age, while all other cranial sutures remain patent. Therefore, immunohistochemical analysis of the fusing posterior frontal suture was compared with the patent sagittal suture at multiple time points from the fetus through adult. Whereas the intensity of immunostaining was the same in the posterior frontal and sagittal sutures in the fetal rat, there was increased immunoreactivity for TGF-beta isoforms in the actively fusing posterior frontal suture compared with the patent sagittal suture starting 2 days after birth and continuing until approximately 20 days. There were intensely immunoreactive osteoblasts present during fusion of the posterior frontal suture. In contrast, the patent sagittal suture was only slightly immunoreactive. A differential immunostaining pattern was observed among the TGF-beta isoforms; TGF-beta 2 was the most immunoreactive isoform and was also most strongly associated with osteoblasts adjacent to the dura and the margin of the fusing suture. Since the increased expression of TGF-beta 2 during suture fusion suggested a possible regulatory role, recombinant TGF-beta 2 was added directly to the posterior frontal and sagittal sutures in vivo to determine if suture fusion could be initiated. Exogenously added TGF-beta 2 stimulated fusion of the ectocranial surface of the posterior frontal suture. These data provide evidence for a regulatory role for these growth factors in cranial suture development and fusion. Additionally, the intense immunostaining for TGF-beta 2 in the dura mater underlying the fusing suture supports a role for the dura mater in suture fusion. It is possible that premature or excessive expression of these factors may be involved in the etiopathogenesis of craniosynostosis and that modulation of the growth factor profile at the suture site may have potential therapeutic value.

Studies in cranial suture biology: part II. Role of the dura in cranial suture fusion.

The biology underlying normal and premature cranial suture fusion remains unknown. The purpose of this study was to investigate the role of the dura mater in cranial suture fusion. In the Sprague Dawley rat model, the posterior frontal cranial suture fuses between 10 and 20 days of postnatal life. The effect of separating the posterior frontal cranial suture from its underlying dura mater with an intervening silastic sheet was studied. Sixty rat pups, age 8 days, were divided into four groups of 15. Group A served as unoperated controls. Group B, the experimental group, underwent craniotomy, dural elevation, and insertion of a silicone sheet between the posterior frontal cranial suture and the underlying dura. Two operative sham groups were included. Group C underwent craniotomy and dural deflection only. Group D underwent craniotomy alone without dural deflection. The rats were sacrificed at 15, 22, and 30 days of age. The results showed that the unoperated animals (group A) demonstrated normal initiation of suture fusion at 15 days and complete fusion by 22 days. Group B animals, with silicone sheet barriers placed, showed persistent patency of sutures at 22 days. Initiation of suture fusion was delayed until 30 days. Sham group C, animals with craniotomy and dural deflection, showed that initiation of fusion was delayed until 22 days with complete fusion by 30 days of age. Sham group D, craniotomy alone, had the same normal temporal sequence of suture fusion as the unoperated control group A. These data indicate that normal cranial suture fusion is delayed when the suture-dural interaction is interrupted by a surgically place barrier or by simple dural deflection. Furthermore, interaction between the dura and the overlying suture appears to direct suture fusion.

The use of a spectrophotometric assay to study the interaction of S-adenosylmethionine synthetase with methionine analogues.

We have developed a continuous spectrophotometric assay for S-adenosylmethionine synthetase and, using this assay, have examined the interaction of five potential inhibitors with the E. coli enzyme. S-Vinylhomocysteine and S-allylhomocysteine were found to be substrates, while S-(methanethio)cysteine and S-(methanethio)homocysteine were found to be competitive inhibitors. S-Cyanohomocysteine is neither a substrate nor an inhibitor.