Utilizing Surgeon-Performed Intraoperative Translaryngeal Ultrasound for Verifying Vocal Fold Function: A Troubleshooting Approach for Intraoperative Neuromonitoring in Neck Surgery.

INTRODUCTION: We investigated transcutaneous laryngeal ultrasonography (TLUS) for assessing vocal fold (VF) mobility during thyroid and parathyroid surgeries, emphasizing its precision and utility in signal loss scenarios. METHODS: Between October 2020 and January 2023, we performed TLUS, Doppler sonography, laryngeal twitch response (LTR) palpation, and electromyography (EMG) to monitor recurrent laryngeal nerve function during neck surgeries. Postoperatively, the VF activity was verified using fiberoptic video laryngoscopy (FL). Concordance with FL was categorized based on VF activity. RESULTS: Of the 443 VF evaluations, no instances of permanent bilateral paralysis were noted. Temporary unilateral palsy was found in 3.38% and permanent in 0.45%. TLUS displayed 97.8% agreement with EMG and was diagnostically superior (99.7% vs 98.2%) and more affordable ($68 vs $300) compared to analogous operative durations. CONCLUSION: TLUS rivals EMG in terms of intraoperative neuromonitoring accuracy and outperforms LTR. Being cost-effective, TLUS can effectively address signal loss situations, thereby averting additional surgeries.

Predicting coexisting thyroid cancer with primary hyperparathyroidism in an endemic region of multinodular goiter: evaluating the effectiveness of preoperative inflammatory markers.

Purpose: The aim is to examine the efficacy of inflammatory indicators to predict thyroid cancer in patients with primary hyperparathyroidism (PHPT) in an endemic region of nodular goiter. Methods: The prospective database was reviewed to identify patients operated on with the diagnosis of PHPT and thyroid disease between April 2015 and June 2021. Permanent pathologic reports were used as the gold standard for diagnosis. Detailed imaging data with peripheral blood inflammation indices were analyzed to assess their predictive values for concomitant PHPT with thyroid cancer. Postoperative complications and the duration of hospitalization were also reviewed. Results: Thyroid malignancy accompanying PHPT was found in 13 patients (26.0%) out of 50 who had concurrent surgery. The analysis regarding inflammatory indexes revealed nothing significant between thyroid cancer and preoperative blood biochemistry (P > 0.05). In the concurrent surgery group, recurrent laryngeal nerve injury was observed in 1 patient (2.0%) and the mean hospital stay was longer. Conclusion: In endemic regions of nodular thyroid disease, thyroid cancer might accompany PHPT. The value of inflammatory indexes to predict thyroid malignancy in PHPT is controversial and should not be employed in the surgical decision-making process.

The effects of ultrasound-guided serratus anterior plane block on intraoperative opioid consumption and hemodynamic stability during breast surgery: A randomized controlled study.

AIM: To determine effect of ultrasound-guided serratus anterior plane block (SAPB) on intraoperative opioid consumption in patients undergoing oncoplastic breast surgery under general anesthesia. METHODS: This study was conducted as a prospective, randomized controlled trial. Forty-four patients enrolled, aged 18 to 75 years with American Society of Anesthesiologists physical status I to III, undergoing elective oncoplastic breast surgery. Patients were randomly allocated to receive SAPB with 20 mL of 0.25% bupivacaine + general anesthesia (group SAPB) or only general anesthesia (group control). The primary outcome was assessing the effect of SAPB on intraoperative remifentanil consumption. Patients were assessed for emergence time, hemodynamic parameters, doses of rescue drugs used to control hemodynamic parameters, and duration of stay in the recovery room. RESULTS: Preoperative SAPB with 0.25% bupivacaine reduced intraoperative opioid consumption (851.2 ± 423.5 vs 1409.7 ± 756.1 µg, P = .019). Emergence time was significantly shorter in group SAPB (6.19 ± 1.90 minutes) compared to group control (9.50 ± 2.39 minutes; P < .001). There were no significant differences in the doses of rescue drugs used for systolic blood pressure and heart rate between the groups. CONCLUSIONS: Preoperative SAPB with bupivacaine reduced intraoperative opioid consumption and shortened emergence time and duration of stay in the recovery unit, and hemodynamic stability was maintained without block-related complications.

Management of endocrine surgical disorders during COVID-19 pandemic: expert opinion for non-surgical options.

PURPOSE: The COVID-19 pandemic brought unprecedented conditions for overall health care systems by restricting resources for non-COVID-19 patients. As the burden of the disease escalates, routine elective surgeries are being cancelled. The aim of this paper was to provide a guideline for management of endocrine surgical disorders during a pandemic. METHODS: We used Delphi method with a nine-scale Likert scale on two rounds of voting involving 64 experienced eminent surgeons and endocrinologists who had the necessary experience to provide insight on endocrine disorder management. All voting was done by email using a standard questionnaire. RESULTS: Overall, 37 recommendations were voted on. In two rounds, all recommendations reached an agreement and were either endorsed or rejected. Endorsed statements include dietary change in primary hyperparathyroidism, Cinacalcet treatment in secondary hyperparathyroidism, alpha-blocker administration for pheochromocytoma, methimazole ± ß-blocker combination for Graves' disease, and follow-up for fine-needle aspiration results of thyroid nodules indicated as Bethesda 3-4 cytological results and papillary microcarcinoma. CONCLUSION: This survey summarizes expert opinion for the management of endocrine surgical conditions during unprecedented times when access to surgical treatment is severely disrupted. The statements are not applicable in circumstances in which surgical treatment is possible.

Association of biochemical and clinical parameters with parathyroid adenoma weight. Turkish-Bulgarian endocrine and breast surgery study group, hyperparathyroidism registry study.

BACKGROUND: Primary hyperparathyroidism (pHPT) caused by a single benign parathyroid adenoma is a common endocrine disorder that is affected by regional differences. Living in different geographical regions reveals differences in the laboratory results and pathological findings, but studies on this subject are not sufficient. The article focuses on biochemical and pathological effects of geographical differences in parathyroid adenoma. In addition, the present study seeks to elaborate on treatment methods and effectiveness of screening in geographical area of Bulgaria and Turkey. METHOD: In this prospective study, 159 patients were included from 16 centres. Demographic characteristics, symptoms, biochemical markers and pathologic characteristics were analysed and compared between 8 different regions. RESULTS: Patients from Turkish Black Sea had the highest median serum calcium (Ca) level, whereas patients from Eastern Turkey had the lowest median serum phosphorus (P) level. On the other hand, there was no significant difference between Ca, parathormone (PTH) and P levels according to regions. Patients from Eastern Turkey had the highest adenoma weight, while patients from Bulgaria had the lowest adenoma weight. The weight of adenoma showed statistically significant differences between regions (p < 0.001). There was a correlation between adenoma weight and serum PTH level (p = 0.05) and Ca level (p = 0.035). CONCLUSION: This study has provided a deeper insight into the effect of the regional differences upon clinicopathological changing and biochemical values of pHTP patients with adenoma. Awareness of regional differences will assist in biochemical screening and treatment of this patient group.

Diagnostic Accuracy of Axillary Ultrasound for Prediction of Axillary Pathologic Response after Neoadjuvant Treatment in Breast Cancer.

Background: In the era of NAT, to accurately predict pathologic response is a great challenge, which might influence surgical approach for breast and axilla. Axillary staging via imaging methods as an adjunct have long been used with various reported accuracy rates. However, the role of preoperative axillary ultrasonography (AUS) in clinical N0 patients after NAT is still controversial. The primary goal of the present study was to evaluate the precision of preoperative AUS for identifying pathologic complete response (ypCR = ypT0, ypN0) after NAT. Methods: A single-institution, retrospective review of a prospectively maintained database was analyzed to identify breast cancer patients treated with NAT. Only those patients who underwent AUS and 18F-FDG-PET/CT before and after NAT with documentation of clinical and radiological response were incorporated for outcome analysis. Results: In 253 consecutive invasive breast cancer patients axillary ypN0 disease was achieved in 67.19%. In 11.23% ynon-pCR patients AUS failed to detect residual disease presence 80% of which were ITCs and micrometastases. Macrometastasis was present in 21.73% (55/253) of the cases 98.18% (54/55) of which was determined by AUS. Overall accuracy for axillary pCR was found to be 89.32% for AUS and 76.28 % for 18-FDG-PET/CT. The false negative rate (FNR) of AUS and 18-FDG-PET/CT was 12.04% and 15.59%, respectively. The PPV of AUS was higher in Luminal-like tumors (%87.69), whereas HER-2 positive (%100) and triple-negative (93.47%) subtypes had higher NPV. Conclusions: AUS is a beneficial tool with the potential of accurate prediction of pCR in more than 80% of patients following NAT. Nevertheless, in cases of residual ITCs and micrometastasis the accuracy of US should be interrogated cautiously.

Surgical Trends in Breast Cancer in Turkey: An Increase in Breast-Conserving Surgery.

PURPOSE: Breast cancer is the most frequent cancer in women, and there is a great variability in surgical practice for treating that cancer in different countries. The aims of this study were to analyze the effect of guidelines from the Turkish Federation of Breast Diseases Societies on academic institutions that have breast centers and to evaluate surgical practice in Turkey in 2018. PATIENTS AND METHODS: Between January and March 2019, a survey was sent to breast surgeons who were working in breast centers in academic institutions. The sampling frame included 24 academic institutions with breast centers in 18 cities in Turkey to evaluate interdisciplinary differences among breast centers and seven regions in Turkey regarding patients' choices, surgical approaches, and academic institutions. RESULTS: All surgeons responded to the survey, and all 4,381 patients were included. Most of the surgeons (73.9%) were working in a breast center. Multidisciplinary tumor boards were performed in 87% of the breast centers. The average time between clinical evaluation and initiation of treatment was 29 days; the longest time was in Southeast Anatolia (66 days). Only 6% of patients had ductal carcinoma in situ. Sentinel lymph node biopsy was available in every region across the country and was performed in 64.5% of the patients. In 2018, the overall breast-conserving surgery rate was 57.3% in Turkey, and it varied from 72.2% in the Black Sea region to 33.5% in Central Anatolia (P < .001). Oncoplastic breast surgery options were available at all breast centers. However, 25% of the breast centers from the Black Sea region and half the breast centers from Eastern Anatolia and the Mediterranean region did not perform this type of surgery. CONCLUSION: Increasing rates of nonpalpable breast cancer and decreasing rates of locoregional recurrences favored breast-conserving surgery, especially in developed countries. Guidelines from the Turkish Federation of Breast Diseases Societies resulted in more comprehensive breast centers and improved breast health in Turkey.

Focused parathyroidectomy without intra-operative parathormone monitoring: The value of PTH assay in preoperative ultrasound guided fine needle aspiration washout.

BACKGROUND: The accurate identification of hyperfunctioning parathyroid (HP) gland is the only issue for definitive surgical treatment in primary hyperparathyroidism (pHPT). Various imaging and operative techniques have been proposed to confirm the localization of the diseased gland. Nevertheless, none of these methods proved to be the gold standard. The presented study aimed to assess the value of parathyroid hormone assay in preoperative ultrasound guided fine needle aspiration (FNA)-PTH washout fluid to verify the correct localisation for focused parathyroidectomy without intra-operative PTH monitoring. MATERIAL AND METHODS: The retrospective analysis of 57 patients with pHPT who underwent FNA-PTH was conducted from a prospective database. Biochemical assessment together with radiological (ultrasonography) and nuclear (MIBI scan) imaging was reviewed. Associations between FNA-PTH washout values and localization technics were evaluated and compared in terms of operative findings. RESULTS: Focused parathyroidectomy without intraoperative PTH monitoring was performed to 45 patients with high FNA-PTH values. The median largest diameter of the target parathyroid lesion identified by ultrasonography was 13 mm (range, 6 to 36). The median serum PTH level was 190 pg/mL (range, 78 to 1709; reference range, 15 to 65) whereas the median washout PTH was 2500 pg/mL (range, 480 to 3389). According to operative findings high FNA-PTH levels correctly identified parathyroid adenoma in 40 cases (89% of sensitivity and 100% of specificity and positive predictive value) whereas MIBI scan localized the lesion in 36 of these cases (80% of sensitivity). CONCLUSIONS: The higher level of PTH in preoperative ultrasound guided FNA washout is a considerable data to predict the correct localization of HP, particularly in circumstances of greater values than the serum PTH level. However, although its specificity is high, in cases of coexisting nodular thyroid disease, associated additional HP might be missed at focused parathyroidectomy without PTH monitoring, leading to recurrent disease.

Effects of ozone oxidative preconditioning on liver regeneration after partial hepatectomy in rats.

AIM: Similar protective effect of ischemic and ozone oxidative preconditioning (OzoneOP) in hepatic ischemia-reperfusion (I/R) injury was demonstrated, providing evidences that both preconditioning settings shared similar biochemical mechanisms of protection. We investigated the effects of OzoneOP on liver regeneration after 70% partial hepatectomy (PHx) in rats. METHODS: Rats were divided into three groups: PHx, I/R + PHx, and OzoneOP + I/R + PHx groups. Ozone (intraperitoneal, 1.2 mg/kg) was given to rats subjected to I/R and 70% hepatectomy daily five times before operation. At 24 hr and 48 hr after resection, samples were collected for the measurement of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6). Moreover, liver regeneration rate, proliferating cell nuclear antigen (PCNA) labeling index, mitotic index, and histopathological examination were evaluated. RESULTS: OzoneOP reduced liver injury determined by liver histology and serum transaminases. There was a rise in serum TNF-α and IL-6 levels in the I/R + PHx group whereas OzoneOP significantly decreased the rise in the level of TNF-α but not IL-6 on the 24 hr and 48 hr of reperfusion. Moreover, liver regeneration in OzoneOP + PHx group, as assessed by the regenerated liver weight, mitotic, and PCNA-labeling index, was significantly improved when compared to I/R + PHx group. CONCLUSION: These results suggest that OzoneOP ameliorates the hepatic injury associated with I/R and has a stimulatory effect on liver cell regeneration that may make it valuable as a hepatoprotective modality.

Effect of erythropoietin on liver regeneration in an experimental model of partial hepatectomy.

BACKGROUND AND AIM: The liver shows remarkable regeneration ability after damage or resection. The main stimulant for hepatic regeneration is resection. Erythropoietin (EPO), which was initially used for anemia therapy, is today known as a general tissue protector owing to its anti-inflammatory, anti-oxidant, anti-apoptotic, and angiogenic properties. This study aims to investigate the effect of systemically administered EPO on liver regeneration after partial hepatectomy. METHODS: Forty-eight male Wistar albino rats were randomly split in two groups A and B consisting of 24 rats each. Standard 70% hepatectomy was performed on the rats in group A. The same surgical procedure was performed on the rats in group B, and they were additionally administered 3000 U/kg/subcutaneous EPO. The rats were sacrificed 24, 48, and 72 h after resection. The groups were compared in terms of biochemical, morphological, and histopathological parameters. RESULTS: The biochemical results showed that the administration of EPO decreased aspartate aminotransferase levels significantly (p < 0.05) at 24 h after hepatectomy. A comparison of the groups in terms of relative liver weight showed that EPO-treated groups exhibited a statistically significant increase (p < 0.05) for all three time periods. Histopathology results showed that in the EPO-treated groups, the mitosis index at 48 and 72 h, double nuclei cell number at 72 h, and proliferating cell nuclear antigen ratio at 48 h showed a significant increase (p < 0.05). CONCLUSION: Our study showed that systemically administering high-dose EPO increases regeneration by affecting the biochemical, morphological, and histopathological parameters after liver resection.

The effect of erythropoietin on anastomotic healing of irradiated rats.

AIM: The aim of the present study is to evaluate the possible protective effects of erythropoietin (EPO) on anastomotic wound healing after preoperative radiotherapy according to its pleiotropic mechanism of action. METHODS: Thirty-two male Wistar albino rats were randomized into four groups containing eight rats each: ANAS group, standard resection plus anastomosis; RT+ANAS group, radiation plus standard resection plus anastomosis; ANAS+EPO group, standard resection plus anastomosis plus EPO; RT+ANAS+EPO, radiation plus standard resection plus anastomosis plus EPO. All animals were sacrificed by cardiac puncture, and anastomotic healing was measured by bursting pressure, hydroxyproline (OHP) levels, myeloperoxidase (MPO) activity and histopathological evaluations. Malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), and matrix metalloproteinase-9 (MMP-9) were also measured in serum specimens. RESULTS: OHP levels in the RT+ANAS + EPO group were significantly increased compared with other groups (p < .05). In contrast, MPO activity in the RT+ANAS+EPO group was significantly decreased compared with other groups (p < .05). Serum MDA levels were found to be decreased in the ANAS+EPO and RT+ANAS+EPO groups (p < .05). Group comparisons demonstrated that bursting pressure was significantly higher in EPO treated rats (p < .05). The histopathology results revealed that EPO treatment improves anastomotic wound healing though decreased necrosis and inflammatory cell infiltration and increased fibroblast activity. CONCLUSION: The findings of the present study indicate that EPO contributes to wound healing and the strength of colon anastomosis following radiation due to its antioxidant and anti-inflammatory effects, but further studies are needed to explore the significance of these effects.

N-acetyl-cysteine improves anastomotic wound healing after radiotherapy in rats.

AIM: This study was designed to determine the effects of intraperitoneally or orally administered N-acetylcysteine (NAC) on anastomotic healing of irradiated rats. METHODS: Thirty-two male Wistar albino rats were randomized into four groups containing 8 rats each: I; standard resection plus anastomosis, II; radiation plus standard resection plus anastomosis, III; radiation plus standard resection plus anastomosis plus oral NAC, IV; radiation plus standard resection plus anastomosis plus intraperitoneal NAC. Four types of assessment were performed: bursting pressure, hydroxiproline (OHP) content, histopathology, and biochemical evaluation, including serum malondialdehyde (MDA), advanced oxidation protein products (AOPP), reduced glutathione (GSH) and superoxide dismutase (SOD) activities. RESULTS: Group comparisons demonstrated that bursting pressure was significantly higher in NAC treated rats. The mean tissue OHP concentration in the anastomotic tissue was significantly lower in irradiated rats (group II) than in the other groups. NAC treatment caused increased activity of SOD and GSH. In contrast, MDA levels were found to be decreased in groups III and IV. Histopathological analysis revealed that NAC administration, either orally or intraperitoneally, leads to a better anastomotic healing in terms of reepithelialization, perianastomotic fibrosis, ischemic necrosis, and muscle layer destruction. CONCLUSION: The present study supports the hypothesis that NAC administration alleviates the negative effects of radiotherapy on anastomotic healing. Nevertheless, the underlying mechanisms responsible for this protective effect is unknown today.

Bacterial translocation in experimental stroke: what happens to the gut barrier?

The reasons of post-stroke infections are still incompletely understood. Bacterial translocation (BT), the passage of viable microbes across an even anatomically intact intestinal barrier, has been described in many critical illnesses. To date, it has not been studied as a source of infection in an animal stroke model. To address this, a permanent left middle cerebral artery occlusion (MCAO) model in rats was used. After 24, 48, and 72 hours (h), sham and experimental groups were sacrificed and samples were taken for BT. Similarity between bacteria detected in tissues (blood, mesenteric lymph node, liver, spleen, and lung) and intestinal microflora was shown with phenotypic methods and antibiotyping. Possible ileum tissue injuries were shown by histopathologic examination (including morphometric analysis). Although there was no bacterial proliferation in the sham groups, 55.5%, 45.4%, and 30% bacterial proliferation was detected in MCAO groups at postoperative hour 24, 48, and 72, respectively. In MCAO groups the bacterial proliferation in tissues and ileum tissue injury scores were higher over time compared to sham groups (p < 0.05). Our findings support the view that stroke, itself leads to mucosal damage and bacterial translocation (Tab. 5, Fig. 2, Ref. 27).

Effect of 2-octyl-cyanoacrylate on ischemic anastomosis of the left colon.

INTRODUCTION: 2-octyl-cyanoacrylate may be a good alternative in ischemic colon anastomosis without impairment of tissue perfusion. METHODS: Forty male Wistar albino rats were randomized into four experimental groups (n = 10 in each group). In group 1 (control), a well-perfused left colonic segment was transected, and free ends were anastomosed by propylene sutures. In groups 2, 3, and 4, the animals underwent a standardized surgical procedure to induce ischemic left colon anastomosis. In group 2, an end-to-end anastomosis was created using six interrupted 6-0 polypropylene sutures between ischemic edges. In group 3, after approximating the mesenteric and antimesenteric edges of the anastomosis with two 6-0 polypropylene sutures, 2-octyl-cyanoacrylate was applied between the edges. In group 4, anastomosis was created by the same technique as described in group 2, and additionally 2-octyl-cyanoacrylate was applied on suture line. Rats were killed on day 4 following operation. Anastomotic integrity, intraperitoneal adhesion scores, anastomotic bursting pressures, and tissue hydroxyproline levels were recorded. Histopathological examination of the anastomosis was also performed. RESULTS: There were no statistically significant differences among groups with respect to anastomotic integrity (p =.142). The mean bursting pressure values were 81.1 +/- 23.83, 43.3 +/- 26.06, 15.8 +/- 11.3, and 17.6 +/- 18.02 in groups 1, 2, 3, and 4, respectively. There were no statistically significant differences among groups 2, 3, and 4 with respect to tissue hydroxyproline levels and bursting pressure levels. The highest adhesion scores were observed in groups 3 and 4. DISCUSSION: 2-octyl cyanoacrylate does not have additional advantages in the healing of experimental ischemic colon anastomosis.

Erythropoietin: a possible cytoprotective cytokine in acute necrotizing pancreatitis.

BACKGROUND/PURPOSE: Despite decades of research and clinical trials, a specific therapeutic treatment for acute pancreatitis (AP) has yet to be developed. The aim of the present study was to investigate the effects of erythropoietin on the severity of taurocolic acid-induced acute necrotizing pancreatitis. METHODS: Forty-seven male Wistar albino rats were randomized into seven experimental groups. In group I, animals were sham-operated (n = 5). In groups II, III, IV, IIepo, IIIepo, and IVepo, AP was induced by sodium taurodeoxycholate treatment (n = 7). In groups II, III, and IV, 1 ml normal saline and in groups IIepo, IIIepo, and IVepo, 1000 U/kg body weight erythropoietin (EPO) was administered intramuscularly immediately after the induction of AP. Animals were killed at 24, 48, and 72 h postoperatively. Histopathological and biochemical evaluations were performed. RESULTS: The serum levels of interleukin-6 (IL-6) and tissue levels of malondialdehyde were found to be significantly lower in EPO-administered groups when compared with the levels in groups without EPO treatment. The severity of pancreatic edema, acinar necrosis, inflammation, and perivascular infiltrate were reduced in all the EPO groups compared with the no-treatment groups. CONCLUSIONS: Our findings may reflect the possible cytoprotective effect of EPO in acute necrotizing pancreatitis.

Does sildenafil reverse the adverse effects of ischemia on ischemic colon anastomosis: yes, 'no'.

INTRODUCTION: Sildenafil may lead an improvement in anastomotic healing of ischemic left colon anastomosis. METHODS: Thirty-six male Wistar albino rats were randomized into four experimental groups (n=9 in each group). In group 1, a well-perfused left colonic segment was transected, and free ends were anatomosed. In groups 2, 3 and 4 animals underwent a standardized surgical procedure to induce ischemic left colon anastomosis. Group 2 animals received only tap water. In groups 3 and 4 animals received 10mg/kg/body-weight and 20mg/kg/body-weight sildenafil, single dose a day during 4 days, respectively. Rats were sacrificed on day 4 following operation. Anastomotic integrity, intra-peritoneal adhesion scores, anastomotic bursting pressures and tissue hydroxyproline levels were recorded. Histopathological examination of the anastomosis was also performed. RESULTS: There was no statistically significant difference among groups with respect to anastomotic integrity (p=0.142) but ischemia decreased the anastomotic bursting pressure. The mean bursting pressure values were 78.8+/-24.1, 43.3+/-26, 55.1+/-32.4, and 43.3+/-20.4 in groups 1, 2, 3, and 4, respectively. Group 1 had the highest values whereas; there was no statistically significant difference between groups 1 and 3. There was no statistically significant difference among groups 2, 3, and 4 with respect to tissue hydroxyproline levels, adhesion scores and the Chiu scores. The highest inflammatory cell presence in the granulation tissue was detected in group 2, whereas the lowest was detected in group 4 (p=0.0001). The highest fibroblast infiltration in the granulation tissue was detected in group 1 (p=0.045). DISCUSSION: Our results showed that 10mg/kg sildenafil decreased the adverse effects of ischemia on the healing of ischemic left colon anastomosis. Additional investigations are needed to confirm the effects of phosphodiesterase-5 inhibitors in ischemic colon anastomosis models.