Blas Flor

Efficacy and Cost-Effectiveness of the UltraCision® Harmonic Scalpel in Thyroid Surgery: An Analysis of 200 Cases in a Randomized Trial

BACKGROUND Thyroid surgery technique has undergone very few changes in the last century. The UltraCision harmonic scalpel (UHS) (Smithfield, RI) has been widely used in laparoscopic surgery and is documented to be safe and fast for cutting and coagulating tissue. We studied whether the use of the UHS could have advantages in thyroid surgery in terms of operative time, length of hospitalization, morbidity, and general costs. METHOD Our study was a prospective randomized trial of thyroidectomies and lobectomies performed for benign thyroid diseases in an endocrine surgery unit between February 2001 and July 2002. Patients were randomized in two groups: group A (n=100) underwent thyroidectomy using UHS and group B (n=100) with the conventional clamp-and-tie technique. Main outcome measures were demographics, operating time, length of hospitalization, intra- and postoperative complications, sequelae, and general costs. We used the unpaired 2-tailed Students t test and the chi2 test to compare the series. RESULTS The two groups were similar in age and sex. Mean +/- SD operative time was shorter in the UHS group compared with the conventional technique group for both lobectomy (61 +/- 06 vs. 78 +/- 10 minutes) and total thyroidectomy (86 +/- 20 vs. 101 +/- 16 minutes). Length of hospitalization was similar in both groups (1.07 vs. 1.15 days). We did not find statistical differences between the two techniques regarding transient postoperative complications. There were no deaths, no blood transfusions, no intraoperative complications, and no postoperative definitive sequelae. The global charges for every patient were significantly less in the UHS group (985.77 +/- 107.08 euro vs. 1148.40 +/- 153.25 euro). CONCLUSION The use of ultrasonically activated shears resulted in a reduction of 15-20% in operative time and was cost-effective compared to the conventional technique group.

Outcome of Esophageal Function and 24-hour Esophageal pH Monitoring after Vertical Banded Gastroplasty and Roux-en-Y Gastric Bypass

Background: One of the co-morbidities frequently associated with morbid obesity is gastro-esophageal reflux disease (GERD), present in >50 % of morbidly obese individuals. We compared the anti-reflux effect of vertical banded gastroplasty (VBG) and Roux-en-Y gastric bypass (RYGBP), and their effect on esophageal function. Methods: 10 patients underwent VBG and 40 patients underwent RYGBP. Anthropometric parameters, symptomatology of GERD, esophageal manometry (EM), isotopic esophageal emptying (IEE) and 24hr esophageal pH monitoring were recorded in all patients preoperatively, and at 3 months and 1 year postoperatively. Results: Preoperatively, there was a high prevalence of GERD, symptomatic and pH-metric in both groups (57% and 80% respectively). The preoperative values of EM and IEE parameters were within the normal range in most patients. After surgery, there was an improvement at 3 months postoperatively in both groups. 1 year after surgery, the VBG group presented symptomatic GERD in 30% and pH-metric reflux in 60% of patients while the RYGBP group presented symptomatic GERD and pH-metric reflux in 12.5% and 15% of patients, respectively. There was an increase in postoperative sensation of dysphagia in both groups (70% VBG, 30% RYGBP) one year after operation. After surgery, differences in all EM parameters were minimal, and never reached statistical significance for any group (VBG and RYGBP). The IEE showed a significantly higher percentage of esophageal retention after surgery, but this retention was always within the normal range. Both groups had an improvement in anthropometric parameters, but 1 year after surgery the results were significantly better in RYGBP patients (70% excess weight loss) than in VBG patients (46% excess weight loss). Conclusion: >50% of morbidly obese individuals suffer from GERD. We did not find changes in esophageal function of morbidly obese patients to explain their gastroesophageal reflux preoperatively and postoperatively. EM and IEE studies are not indicated as standard preoperative tests, except in patients with significant symptoms of gastroesophageal reflux. RYGBP is significantly better than VBG as an anti-reflux procedure, and had better weight loss.

Early Prediction of Anastomotic Leak in Colorectal Cancer Surgery by Intramucosal pH

PurposeAdequate oxygenation is necessary for anastomotic healing, and ischemia has been found to be one of the most important factors in anastomotic leakage. This study was designed to assess the value of early postoperative intramucosal pH measurements for the prediction of anastomotic leakage in patients with colorectal anastomosis.MethodsA prospective study of 90 patients with rectal or sigmoid cancer with primary anastomosis was conducted. In all patients intramucosal pH was determined by using tonometry at the anastomotic and gastric levels during the first 24 and 48 hours postoperatively. Seven other variables also were tested by univariate and multivariate analysis for any association with anastomotic leakage.ResultsThe rate of clinical anastomotic leakage was 6.6 percent. Multivariate analysis showed that only the intramucosal pH at the anastomosis was an independent factor for the development of anastomotic leakage. The risk of leakage was 22 times higher in patients with an anastomotic intramucosal pH < 7.28 in the first 24 hours after surgery.ConclusionsMeasurement of anastomotic intramucosal pH in the early postoperative period can more accurately predict the risk of anastomotic leakage and benefit those patients who would need additional measures to improve the viability of the anastomosis.

Relaxation of human isolated mesenteric arteries by vasopressin and desmopressin

1 The effects of vasopressin and deamino‐8‐D‐arginine vasopressin (DDAVP, desmopressin) were studied in artery rings (0.8‐1 mm in external diameter) obtained from portions of human omentum during the course of abdominal operations (27 patients). 2 In arterial rings under resting tension, vasopressin produced concentration‐dependent, endothelium‐independent contractions with an EC50 of 0.59 ± 0.12 nm. The V1 antagonist d(CH2)5Tyr(Me)AVP (1 μ) and the mixed V1‐V2 antagonist desGly‐d(CH2)5D‐Tyr(Et)ValAVP (0.01 μm) displaced the control curve to vasopressin to the right in a parallel manner without differences in the maximal responses. In the presence of indomethacin (1 μm) the contractile response to vasopressin was significantly increased (P < 0.01). 3 In precontracted arterial rings, previously treated with the V1 antagonist, d(CH2)5Tyr(Me)AVP (1 μm), vasopressin produced endothelium‐dependent relaxation. This relaxation was reduced significantly (P < 0.05) by indomethacin (1 μm) and unaffected by the V1‐V2 receptor antagonist desGly‐d(CH2)5D‐Tyr(Et)ValAVP (1 μm) or by NG‐nitro‐L‐arginine methyl ester (L‐NAME, O.1 μm). 4 The selective V2 receptor agonist, DDAVP, caused endothelium‐independent, concentration‐dependent relaxations in precontracted arterial rings that were inhibited by the mixed V1‐V2 receptor antagonist, but not by the V1 receptor antagonist or by pretreatment with indomethacin or L‐NAME. 5 Results from this study suggest that vasopressin is primarily a constrictor of human mesenteric arteries by V1 receptor stimulation; vasopressin causes dilatation only during V, receptor blockade. The relaxation appears to be mediated by the release of vasodilator prostaglandins from the endothelial cell layer and is independent of V2 receptor stimulation or release of nitric oxide. In contrast, the relaxation induced by DDAVP is largely dependent on stimulation of V2 receptors.

Macroscopic Assessment of Mesorectal Excision in Rectal Cancer: A Useful Tool for Improving Quality Control in a Multidisciplinary Team

High quality of surgical technique and the use of descriptive measures to assess and report surgical proficiency have been shown to influence locoregional tumor control in patients with rectal cancer. In this study, the authors have aimed to audit the implementation of a macroscopic assessment of mesorectal excision (MAME) and to investigate factors that influenced surgical quality and disease recurrence.

Endothelium-dependent component in the contractile responses of human omental arteries to adrenergic stimulation

The present study was designed to investigate the influence of endothelium-derived nitric oxide on the contractile responses of isolated human omental arteries to electrical field stimulation and noradrenaline. We measured isometric tension in artery rings obtained from portions of human omentum during the course of abdominal operations (32 patients). Electrical field stimulation induced frequency-dependent contractions which were abolished by tetrodotoxin (10(-6) M) and prazosin (10(-6) M), thus indicating that this effect was due to noradrenaline released from adrenergic nerves acting on alpha 1-adrenoceptors. The increases in tension induced by electrical field stimulation were of greater magnitude in arteries denuded of endothelium. NG-Nitro-L-arginine (L-NAME, 10(-4) M) potentiated the contractile response to electrical field stimulation in artery rings with endothelium but did not influence the contractile responses of endothelium-denuded arteries. The potentiation induced by L-NAME was completely reversed by L-arginine (10(-4) M), but not by D-arginine (10(-4) M). Contractile responses to noradrenaline were similar in arteries with and without endothelium. L-NAME (10(-4) M) had no significant effect on the contractile responses to noradrenaline. Our results suggest that electrical field stimulation releases endothelium-derived nitric oxide which inhibits the contractile responses of human omental arteries. The constrictor responses to noradrenaline are not modulated by the endothelium.

Vertical Banded Gastroplasty Converted to Roux-en-Y Gastric Bypass: Little Impact on Nutritional Status after 5-Year Follow-up

Background: Conversion to a Roux-en-Y gastric bypass (RYGBP) has been advocated after the failure of vertical banded gastroplasty (VBG). The aim of this study was to analyze the differences in anthropometric and nutritional parameters between patients with VBG and those converted to RYGBP. Methods: 45 patients initially underwent VBG. 22 of these patients have maintained this operation for more than 5 years (Group A) and 23 have been converted to RYGBP (Group B), after 2 years of follow-up. We analyzed anthropometric and nutritional parameters (macronutrients,micronutrients and lipid profile), and postoperative morbidity after both procedures. Data were recorded before the first operation and at 6 months, 1, 2 and 5 years follow-up. Results: VBG failure rate was 51%. The 23 patients converted to RYGBP have maintained an excess weight loss (EWL) of 70% 3 years after the revision, and all the complications related to VBG disappeared. Anthropometric parameters were significantly better after RYGBP. We found no significant differences in nutritional status between both groups except for levels of iron, vitamin B12 and transferrin saturation index, which significantly decreased in converted patients. The redo procedure had a low morbidity rate, with no mortality. Conclusion: More than 50% of VBGs failed after 2-year follow-up. Patients converted to RYGBP maintained mean EWL 73% at 5 years. The only significant nutritional deficiencies were iron and vitamin B12, in patients converted to RYGBP.

Contractile Response of Human Omental Arteries to Endothelin

Abstract— The effects of endothelin have been studied in isolated arterial segments (0·8–1 mm in external diam.) of human omental arteries obtained during the course of abdominal operations (15 patients, 7 men and 8 women). Paired segments, one normal and the other de‐endothelized, were mounted for isometric recording of tension in organ baths. Endothelin produced concentration‐dependent contractions with an EC50 value of 5·4 × 10−9 m. Removal of endothelium did not affect significantly endothelin‐induced contractions (EC50, 6·7 × 10−9 m). Removal of extracellular calcium or addition of the calcium channel blocker nicardipine (10−6 m) diminished but did not abolish responses to endothelin. These results indicate that endothelin exerts powerful contractile effects on human isolated omental arteries which are independent of the presence of an intact endothelial cell layer; this contraction cannot be explained solely by voltage‐dependent calcium channels.

Effects of aspirin, nimesulide, and SC-560 on vasopressin-induced contraction of human gastroepiploic artery and saphenous vein.

Objective:The present experiments were designed to evaluate differences in the effects of cyclooxygenase (COX)-1 and COX-2 inhibition on contractile responses of human gastroepiploic artery and saphenous vein elicited by vasopressin. Design:Laboratory investigation. Setting:University laboratory. Subjects:Rings of human gastroepiploic artery were obtained from 32 patients undergoing gastrectomy, and rings of saphenous vein were obtained from 30 patients undergoing coronary artery bypass surgery. Interventions:The rings were suspended in organ baths for isometric recording of tension. We studied the responses to vasopressin in the absence and in the presence of either the vasopressin V1-receptor antagonist d(CH2)5Tyr(Me)AVP or the COX inhibitors aspirin, nimesulide, or SC-560. Measurements and Main Results:Vasopressin (10−11–10−6 mol/L) produced concentration-dependent contractions with an EC50 value of 4.3 × 10−10 mol/L for gastroepiploic artery and 3.4 × 10−8 mol/L for saphenous vein. The vasopressin V1-receptor antagonist d(CH2)5Tyr(Me)AVP (10−7 mol/L) induced significant shifts (p < .001) of the control curves to the right. The COX-1 and COX-2 inhibitor aspirin (10−6–10−5 mol/L) and the COX-2 inhibitor nimesulide (10−6 mol/L) induced leftward shifts of the concentration-response curve for vasopressin in gastroepiploic artery. Lower concentrations of aspirin or the COX-1 inhibitor SC-560 (10−8 mol/L) did not affect the responses of gastroepiploic artery. COX-1 or COX-2 inhibition did not modify the contraction of saphenous vein to vasopressin. Conclusion:The results provide functional evidence that aspirin at high concentrations and the COX-2 selective inhibitor nimesulide potentiate the contractile response of gastroepiploic artery to vasopressin, thus suggesting the release of relaxant prostaglandins by the peptide. However, contractions of human saphenous vein were unaffected by COX inhibition, indicating that vasopressin does not stimulate the release of prostanoids. The amplifying effect of aspirin on vasopressin-induced contraction may contribute to early graft failure when the gastroepiploic artery is used as a coronary artery bypass graft.

Influence of nitric oxide on neurogenic contraction and relaxation of the human gastroepiploic artery

BACKGROUND The objective of this study was to characterize the neurogenic contraction and relaxation of the human gastroepiploic artery and to determine whether the responses are mediated by nitric oxide (NO) from neural or endothelial origin. METHODS Rings of human gastroepiploic artery were obtained from 18 patients (12 men, 6 women) undergoing gastrectomy. The rings were suspended in organ baths for isometric recording of tension. We studied the contractile and relaxant responses to electrical field stimulation. RESULTS In arteries under resting conditions, electrical field stimulation (2 to 8 Hz) caused frequency-dependent contractions that were of greater magnitude in arteries denuded of endothelium and blocked by tetrodotoxin (10(-6) mol/L). The inhibitor of NO synthesis N(G)-monomethyl-L-arginine (L-NMMA, 10(-4) mol/L) increased contractile responses only in arteries with endothelium. In preparations contracted with norepinephrine in the presence of guanethidine (10(-6) mol/L) and atropine (10(-6) mol/L), electrical stimulation induced frequency-dependent relaxations. This neurogenic relaxation was prevented by L-NMMA (10(-4) mol/L) and tetrodotoxin (10(-6) mol/L), but was unaffected by removal of the endothelium. CONCLUSIONS The results provide functional evidence that NO is released by autonomic nerves of the human gastroepiploic artery. We hypothesize that the release of NO from both endothelial and neurogenic origin may modulate resistance of the human gastroepiploic artery. Dysfunction in any of these sources of NO should be considered in some form of vasospasm.