Anatomy of the splanchnic circulation

Postoperative transverse colon necrosis due to mesenteric injury during laparoscopic surgery for endometrial carcinoma

Hemorrhage and organ injury have been frequently reported as complications associated with trocar puncture in laparoscopic surgery. This report presents a case of delayed intestinal necrosis due to mesenteric injury. A 76-year-old woman who had a history of distal gastrectomy and adrenal insufficiency was diagnosed with stage IA endometrial cancer. We performed laparoscopic total hysterectomy and bilateral salpingo-oophorectomy. The upper abdominal wall and mesentery were adhered, and bleeding from the mesentery was noted during the first trocar puncture of the umbilical region, resulting in ligation and hemostasis. Abdominal pain and fever developed on the third postoperative day, and contrast-enhanced computed tomography demonstrated transverse colon perforation. Emergency laparotomy showed necrosis in the proximal transverse colon and a defect in the marginal artery. Mesenteric injury can lead to delayed intestinal necrosis without intraoperative macroscopic findings. In laparoscopic cases where adhesion is expected, trocar placement should be carefully considered.

Computed-tomography angiography in arterial acute intestinal ischemia: prognostic interest of vascular semiology

PURPOSE

To investigate vascular features on abdominal Computed-Tomography Angiography (CTA) correlated with 48-h mortality in patients who underwent arterial acute intestinal ischemia (AAII) surgery. The secondary objective was to create a prognostic score on the 48-h mortality after surgery, based on the most relevant signs.

METHOD

We included 104 patients who underwent surgery for acute mesenteric ischemia. 2 radiologists retrospectively blind reviewed the preoperative CTA scans. They used a standardized analysis grid for the arterial and venous vascular signs described in angiography. When signs were present, the affected abdominal quadrant was specified in coronal reconstruction. Each sign was analyzed for 48-h mortality on CTA. A score based on signs correlated with early mortality was developed and evaluated by ROC curve analysis.

RESULTS

22 patients died within 48 h. The number of superior mesenteric artery (SMA) branches was significantly reduced in deceased patients (p = 0.006). Other prognostic factors associated with 48-h mortality were decreased venous return in area number 1 corresponding to right colic flexure, proximal half of the transverse colon, proximal ileum (p = 0.04) and decreased venous return in more than 2 zones (p = 0.01). The weighted AAII48 score included 1 protective clinical item and 5 radiological items. The area under the ROC curve was 0.784 with, for a 6-point threshold value, a sensitivity of 68% and a specificity of 77%. The intraclass correlation coefficient for interobserver reproducibility of the score was 0.81 [95% CI 0.73; 0.87].

CONCLUSION

Three vascular signs on CTA were found to be prognostic factors for early mortality: SMA branches number ≤ 5 (p = 0.006), decreased venous return in area 1 (p = 0.04), and > 2 areas of decreased venous return (p = 0.01). They were incorporated into the AAII48 score. This score could help to identify patients at risk and to adapt subsequent management.

Hyperspectral Imaging (HSI)-A New Tool to Estimate the Perfusion of Upper Abdominal Organs during Pancreatoduodenectomy

Simple Summary

Novel intraoperative imaging systems may have a critical impact on intraoperative decision-making. Hyperspectral imaging (HSI) is one of the leading new imaging systems, providing color pictures of tissue characterization, such as oxygen saturation (StO₂) and Near-Infrared Perfusion Index (NIR-PI). Several surgical disciplines have already used HSI in detecting tissue perfusion with a proven record of success. To the best of our knowledge, HSI has not been used in the field of pancreatic surgery yet.

Abstract

Hyperspectral imaging (HSI) in abdominal surgery is a new non-invasive tool for the assessment of the perfusion and oxygenation of various tissues and organs. Its benefit in pancreatic surgery is still unknown. The aim of this study was to evaluate the key impact of using HSI during pancreatoduodenectomy (PD). In total, 20 consecutive patients were included. HSI was recorded during surgery as part of a pilot study approved by the local Ethics Committee. Data were collected prospectively with the TIVITA^® Tissue System. Intraoperative HS images were recorded before and after gastroduodenal artery (GDA) clamping. We detected four patients with celiac artery stenosis (CAS) caused by a median arcuate ligament (MAL). In two of these patients, a reduction in liver oxygenation (StO₂) was discovered 15 and 30 min after GDA clamping. The MAL was divided in these patients. HSI showed an improvement of liver StO₂ after MAL division (from 61% to 73%) in one of these two patients. There was no obvious decrease in liver StO₂ in the other two patients with CAS. HSI, as a non-invasive procedure, could be helpful in evaluating liver and gastric perfusion during PD, which might assist surgeons in choosing the best surgical approach and in improving patients’ outcomes.

The radiologist's guide to duplex ultrasound assessment of chronic mesenteric ischemia

OBJECTIVE

This article reviews the relevant anatomy and physiology of the mesenteric vasculature, familiarizes the radiologist with the accepted diagnostic criteria for mesenteric artery stenosis and its role in the diagnosis of chronic mesenteric ischemia, describes Doppler imaging techniques, and provides protocols for the assessment and surveillance of the mesenteric vasculature before and after revascularization. It also discusses expected changes following revascularization and reviews common post-procedural complications.

RESULTS

Duplex sonography plays an important role in the diagnosis and management of chronic mesenteric ischemia (CMI). Establishing a successful diagnosis is dependent upon knowledge of mesenteric arterial anatomy and physiology as well as sufficient expertise in image optimization and scanning techniques. Although there has been a trend toward utilization of other noninvasive [computed tomographic angiography (CTA), magnetic resonance angiography (MRA), and invasive (digital subtraction angiography (DSA)] imaging modalities for assessment of the mesenteric vasculature, a new era of "imaging wisely" raises legitimate concerns about the effects of ionizing radiation as well as potential effects of CT and MR contrast agents. These concerns are obviated by the use of ultrasound, and recently developed techniques, such as contrast-enhanced ultrasound and vascular applications focused on the evaluation of slow flow, have revealed the vast potential of vascular ultrasound in the evaluation of chronic mesenteric ischemia.

CONCLUSION

Duplex sonography is a cost-effective and powerful tool that can be utilized for the accurate assessment of mesenteric vascular pathology, specifically mesenteric arterial stenosis, and for the evaluation of mesenteric arterial system post revascularization.

Celiac axis stenosis due to median arcuate ligament compression in a patient who underwent pancreatoduodenectomy; intraoperative assessment of hepatic arterial flow using Doppler ultrasonography: a case report

Background

Celiac axis stenosis due to compression by the median arcuate ligament has been reported in patients undergoing pancreaticoduodenectomy; it leads to the development of major collateral pathways that feed the hepatic artery. Dividing these important collaterals during pancreaticoduodenectomy can cause ischemic complications which may lead to a high mortality rate. To prevent these complications, it is necessary to assess intrahepatic arterial flow.

Case presentation

A 71-year-old Japanese man with anorexia was referred to us for the treatment of alcoholic chronic pancreatitis. Computed tomography revealed a pancreatic head tumor with a calculus, associated with the dilatation of the main pancreatic duct and intrahepatic bile duct. Three-dimensional imaging demonstrated focal narrowing in the proximal celiac axis due to median arcuate ligament compression and a prominent gastroduodenal artery that fed the common hepatic artery. The preoperative diagnosis was alcoholic chronic pancreatitis with common bile duct obstruction and celiac axis stenosis due to median arcuate ligament compression. Pancreaticoduodenectomy with median arcuate ligament release was scheduled. Before the division of the median arcuate ligament, the peak flow velocity and resistive index of his intrahepatic artery measured with Doppler ultrasonography decreased from 37.7 cm/second and 0.510, respectively, to 20.6 cm/second and 0.508 respectively, when his gastroduodenal artery was clamped. However, these values returned to baseline levels after the division of the median arcuate ligament. These findings suggested that pancreaticoduodenectomy could be performed safely. Our patient was discharged on postoperative day 17 without significant complications.

Conclusion

The intraoperative quantitative evaluation of intrahepatic arterial blood flow using Doppler ultrasonography was useful in a patient who underwent pancreaticoduodenectomy, who had celiac axis stenosis due to compression by the median arcuate ligament.

Black Anal Canal: Acute Necrosis

Acute ischemia of the rectum or anal canal resulting in necrosis is extremely uncommon because both the rectum and the anal canal have excellent blood supplies. We present a case with spontaneous necrosis of the anal canal without rectal involvement. Surgical debridement was accomplished, and the recovery was uneventful. The patient was elderly, with probable atherosclerotic arterial disease, and presented with hypotension. Due to the lack of other precipitating factors, the hypoperfusion hypothesis seems to be the most suitable in this case. To the best of our knowledge, no similar cases have been reported in the literature on this subject.

Laparoscopic Complete Mesocolic Excision for Stage II/III Left-Sided Colon Cancers: A Prospective Study and Comparison with D3 Lymph Node Dissection

BACKGROUND

To investigate the similarities and differences of laparoscopic complete mesocolic excision (CME) to a colon resection with a D3 lymphadenectomy for the stage II/III left-sided colon carcinoma.

METHODS

Patients between July 2011 and August 2014 were randomized into D3 and CME groups. Mesenteric area, log odds of positive lymph nodes (LODDS), and other operative parameters were collected and assessed.

RESULTS

The average specimen sizes were 5730 ± 828 mm(2) in superior rectal artery (SRA)-preserving D3, 8145 ± 1022 mm(2) in SRA-nonpreserving D3, and 8745 ± 1039 mm(2) in the CME group; the differences were significant (P < .0001). The number of lymph nodes collected from CME specimens was larger, but the CME specimens did not contain an elevated value of LODDS or positive nodes or lymph node ratio (LNR). There were also no significant differences between recovery times of bowel function. Although it took more operation time in D3 approach, especially in SRA-preserving D3 operation, the difference was not significant. Concerning the leakage rate (P = .34) and vessel-related complications (P = .64), there were no significant differences either.

CONCLUSIONS

Both standard D3 resection and CME could achieve a high quality of mesocolic plane grade for stage II/III colon cancer. The LODDS and LNR were comparable, and those were not relevant to mesenteric size.

Update on Colon Ischemia: Recent Insights and Advances

Colon ischemia (CI) is the most common manifestation of ischemic injury to the gastrointestinal (GI) tract. This usually self-limited disease is being diagnosed more frequently, and the list of known causes is increasing. Local hypoperfusion and reperfusion injury are both thought to contribute to the disease process, which manifests with a wide spectrum of injury including reversible colopathy (subepithelial hemorrhage and edema), transient colitis, chronic colitis, stricture, gangrene, and fulminant universal colitis. The distribution is usually segmental with left-sided disease (e.g., inferior mesenteric artery distribution) being more frequently observed than right-sided involvement (e.g., superior mesenteric artery distribution). Any portion of the colon can be affected, but the anatomic distribution of CI recently has been shown to be associated with outcome. Patients with isolated-right colon ischemia (IRCI) have a different presentation and worse outcomes than other distributions of disease. Although somewhat variable depending on disease location, CI presents with cramping abdominal pains over the segment of colon involved followed by a short course of bloody diarrhea. Diagnosis is usually made clinically and is supported with serologic, radiologic, and colonoscopic findings. Colonoscopy is the most accurate diagnostic study. Most patients respond to conservative supportive therapy although some with more severe disease require antimicrobials and/or surgical intervention.

Mesenteric stenosis, collaterals, and compensatory blood flow

BACKGROUND

The mesenteric circulation has an extensive collateral network. Therefore, stenosis in one or more mesenteric arteries does not necessarily lead to symptoms. The objective of this study was to determine the effect of collateral flow on celiac artery (CA) and superior mesenteric artery (SMA) duplex parameters.

METHODS

Between 1999 and 2007, a cohort of 228 patients analyzed for suspected chronic mesenteric syndrome was studied. Stenosis of the mesenteric vessels and collateral flow patterns were identified on angiography and categorized. The effect of stenosis in one mesenteric vessel and the presence of collaterals from the other unaffected vessel was examined in both the CA and SMA.

RESULTS

Stenosis of the CA resulted in a significantly higher peak systolic velocity (PSV) and end-diastolic velocity in the normal SMA without stenosis. This was also found for the CA without stenosis in the presence of a stenosis of the SMA. An incremental effect of the severity of the CA stenosis was found with a mean SMA PSV of 158 cm/s when normal and 259 cm/s when occluded. The presence of collaterals had a clear effect on duplex parameters of the angiographically normal SMA. In the presence of collaterals and a 70% CA stenosis, the PSV in the normal SMA was significantly higher (P = .025).

CONCLUSIONS

This study shows that stenosis in either the CA or SMA increases flow velocities in the other unaffected mesenteric artery. This increase was correlated with the presence of collaterals. Collaterals and stenoses in one of the mesenteric arteries may lead to mimicking or overgrading of stenosis in the other mesenteric artery.

Acute gallbladder necrosis in a patient with acute type B aortic dissection

Although vascular complications induced by acute aortic dissection are varied and common, gallbladder necrosis induced by acute aortic dissection is rare. We experienced the case of a 42-year-old woman who suffered from acute gallbladder necrosis that occurred the following day after the onset of acute type B aortic dissection. Contrasted computed tomography, which showed the thickened wall of the gallbladder and the pericholecystic fluid, as well as the occluded celiac artery, was an effective diagnostic procedure. We performed cholecystectomy and revascularization of the celiac artery using autologous saphenous vein. Her postoperative course was uneventful, and she was discharged after 20 postoperative days.

Acute ischemic gangrene of the rectum: Report of 3 cases and review of literature

INTRODUCTION

Acute ischemia of the rectum resulting in full thickness necrosis is extremely uncommon because of its excellent blood supply.

PRESENTATION OF CASE

We present 3 cases with spontaneous ischemic gangrene of the rectum. All three patients were elderly with atherosclerotic arterial disease and presented with hypotensive shock but in none of these patients we encountered a precipitating factor such as preceding vascular surgery or shock state.

DISCUSSION

A high index of suspicion should be maintained in elderly patients with atherosclerotic disease who present with lower GI symptoms with hypotensive shock and an inflamed rectum on CT scan. Immediate beside proctoscopy should be offered to these patients and if the diagnosis is confirmed these patients should be taken to the operating room immediately. If the entire rectum is found to be gangrenous then an emergency APR should be performed and the perineal wound left open. If the rectum is partially gangrenous then a low anterior resection with Hartman's procedure for diversion is appropriate.

CONCLUSION

Prompt diagnosis and resuscitation followed by immediate surgical intervention is necessary to save these elderly patients.

A review of ischemic colitis: is our clinical recognition and management adequate?

Ischemic colitis is a common cause of hospital admissions; however it is frequently confused intellectually with mesenteric ischemia and often misdiagnosed as infectious diarrhea or Clostridium difficile colitis. Ischemic colitis is caused by non-occlusive insult to the small vessels supplying the colon without a clear precipitating factor. It is more common in females and in patients above 60 years of age. The classic presentation includes sudden onset of lower abdominal pain followed by the urge to defecate and bloody diarrhea. Focal right-sided ischemic colitis has more pain and a worse prognosis. Choosing the correct diagnostic studies is challenging and requires proficient knowledge of the disease. Management is usually conservative, however around 10-20% of the patients will require surgery. Acute ischemic colitis usually resolves; nevertheless some patients may develop chronic segmental colitis or a stricture. One ischemic colitis caveat is that it may be the first sign of undiagnosed cardiac disease. A firm grasp on this common yet little discussed condition is valuable to a gastrointestinal consultant and hospitalist alike.

An extremely uncommon variant of left hepatic artery arising from the superior mesenteric artery

We report a new variation of the left hepatic artery arising from the superior mesenteric artery. The variant was discovered during radiological examinations in a patient presenting with ruptured hepatocellular carcinoma of the left liver lobe. Anatomical description was based on CT-scan and angiographic analysis. When present the left hepatic artery originates from the left gastric artery, with an incidence of 12-34 %. Knowledge of left hepatic artery anatomy is mandatory to optimize surgical and radiological management in complex clinical situations.

Anatomic variations in head and neck reconstruction

Head and neck reconstruction is a technically challenging procedure. Variations encountered in the recipient vessels and commonly used flaps add to the complexity of surgery. This article reviews the commonly encountered variations in the recipient vessels in the neck with emphasis on alternatives and techniques to circumvent these variations. Flaps commonly used in head and neck reconstruction are also reviewed in detail. Furthermore, safety, potential pitfalls, and technical pearls are highlighted.

A case of unresectable rectal necrosis

Introduction. Necrosis of the rectum is an uncommon finding due to abundant collateral vasculature. Its management remains challenging, without clear consensus in the literature. Case Report. We describe a case of a 53-year-old woman with multiple medical comorbidities that presented in septic shock and hematochezia. Colonoscopy revealed ischemic colitis. Conservative management was instituted. At two weeks, she presented evidence of peritonitis. Exploratory laparotomy revealed extensive necrosis of the left colon and rectum. Due to dense inflammation, resection was deemed unsafe. Therefore, a transverse ostomy with mucosal fistula was preformed. Multiple drains were left in place. The patient healed uneventfully. Conclusion. This case illustrates that, if extensive dissection of the distal colon and rectum is unsafe due to the patient's critical condition or technical feasibility, then a diverting ostomy of the proximal viable bowel along with a mucus fistula and good drainage of the abdomen represents an acceptable alternative.

Colon ischemia: recent insights and advances

Ischemic colitis is the most common manifestation of ischemic injury to the gastrointestinal tract, and the variety of defined causes is increasing. Local hypoperfusion and reperfusion injury are both thought to contribute to the disease process, which manifests with a wide spectrum of injury including reversible colopathy (subepithelial hemorrhage and edema), transient colitis, chronic colitis, stricture, gangrene, and fulminant universal colitis. The distribution is typically segmental. Older studies showed that any portion of the colon can be involved; recently, it was established that the site of involvement and prognosis can be correlated. In particular, isolated involvement of the right side of the colon was shown to have a different presentation and worse outcome than ischemic colitis involving other segments. Diagnosis is usually made clinically and supported by radiologic imaging and colonoscopic evaluation. Most patients respond to conservative supportive therapy, although some with severe disease require surgical intervention.

Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: a study of 313 cases supported by histology

OBJECTIVES

Previous reports on the anatomic portions of colon involved in cases of supposed ischemic colitis (IC) have been limited by the absence of confirmation of the true nature of the disease. This is the first anatomic study to define the patterns of colon involvement in which only cases with biopsy-proven or -compatible IC and in which the entire colon had been visualized at surgery or at colonoscopy were included. The aims of this study were to re-examine patterns of colonic involvement in IC using only cases in which the diagnosis was biopsy proven or compatible, and to examine the clinical features and outcomes with regard to the segments of colon involved.

METHODS

A retrospective study was undertaken of patients with IC who were hospitalized at Montefiore Medical Center from 1998 to 2009. Patients were identified using computerized searches of ICD-9 (International Classification of Diseases, ninth revision) codes for colon ischemia, and patterns of colon involvement were then tabulated and categorized into five major groups: right colon, transverse colon, left colon, distal colon, and pancolon involvement. Patterns were classified based on the most proximal location of injury. Major anatomic patterns were then subcategorized into more specific segments of involvement. Only biopsy-proven or -compatible cases of IC in which the entire colon had been visualized at surgery or at colonoscopy were used in this study.

RESULTS

A total of 313 cases of biopsy-proven or -compatible IC were identified. Patterns and frequencies of involvement were: right colon, 25.2%; transverse colon, 10.2%; left colon, 32.6%; distal colon, 24.6%; and pancolon, 7.3%. Compared with all other patterns of IC, the right colon pattern was more likely to be associated with coronary artery disease (39.2 vs. 21.4%) or end-stage kidney disease requiring dialysis (20.3 vs. 7.7%), a longer hospitalization (median stay, 10 vs. 6 days), a greater need for surgery (44.3 vs. 11.5%), and the highest mortality rate (20.3 vs. 9%). Patients with a left colon pattern were less likely to be operated upon, and had a shorter length of stay than any other pattern of IC. Hyperthyroidism, stroke, and chronic obstructive pulmonary disease (COPD) were statistically significant independent predictors of mortality.

CONCLUSIONS

IC is typically a segmental disease, flanked by normal colon on either side of the affected area. Comorbid disease associations and severity of disease as reflected by length of hospitalization, need for surgery, and mortality vary with the segment involved. IC isolated to the right side of the colon is a more severe disease than IC affecting any other segment of colon.

Vascular anomalies encountered during pancreatoduodenectomy: do they influence outcomes?

BACKGROUND

Because of the potential risk of hemorrhage or ischemia, the presence of vascular anomalies adds to the surgical challenge in pancreatoduodenectomy (PD).

OBJECTIVE

To analyze the literature concerning the influence of aberrant peripancreatic arterial anatomy on outcomes of PD.

MATERIALS AND METHODS

A systematic search using Medline and Embase for the years 1950-2008.

RESULTS

The most common aberration in hepatic arterial anatomy is the replaced right hepatic artery. Other vascular abnormalities such as replaced common hepatic artery with a hepatomesenteric trunk and celiomesenteric trunk and arcuate ligament syndrome leading to celiac artery stenosis are also associated with post-PD complications. Damage to the biliary branches of the hepatic arteries increases the risk of postoperative biliary anastomotic leak.

CONCLUSION

The most common abnormalities of the hepatic vasculature include a replaced RHA, replaced LHA, and accessory RHA or LHA. Celiac artery stenosis secondary to median arcuate ligament compression may also be encountered. Every attempt should be made to preserve the aberrant vessel unless their resection is oncologically indicated. Routine preoperative computerized tomography angiography helps to identify the hepatic vascular anatomy and thereby prepares the surgeon to better deal with the vascular anomalies intraoperatively. Increased awareness of the vascular anatomy would decrease the chances of intraoperative vascular injury and consequent postoperative complications such as biliary anastomotic leaks as well as the chances of postoperative hemorrhage.

Anatomic variations of the hepatic arteries in 250 patients studied with 64-row CT angiography

The aim of our study was to determine the frequency of different hepatic arterial variants identified on abdominal CT angiography (CTA) with a 64-row CT system and a high resolution protocol. A total of 250 consecutive abdominal CTAs performed on a 64-row CT system were evaluated. Two radiologists in consensus analyzed arterial phase images; the anatomical findings were grouped according to Michels' classification. An anomalous arterial pattern was observed in 34% of the cases. The most common anomaly was Michels type III (9.2%), followed by types II and V (5.2%), type VI (4.0%), types IV, VII, and IX (2.0%), and type VIII (0.6%). No cases of type X were detected. Unclassified variations were observed in 3.3% of the cases. The new generation of 64-row MDCT allows optimal visualization of splanchnic vascular anomalies with a minimally invasive examination. This visualization is extended to those vessels with a small caliber and slow flow resulting in difficult recognition by classic angiographic studies. The knowledge of anomalous arterial patterns could be very useful in the preoperative planning of surgical and interventional liver procedures.

Laparoscopic D3 lymph node dissection with preservation of the superior rectal artery for the treatment of proximal sigmoid and descending colon cancer

In this paper we report a technique for laparoscopic lymph node (LN) dissection for descending and proximal sigmoid colon cancer with the preservation of the superior rectal artery (SRA) to maintain the blood supply to the distal sigmoid colon. Five (5) cases were included from November 2004 to March 2005. For D3 LN dissection, the root of inferior mesenteric artery was exposed with ultrasonic cutting and coagulating surgical device to avoid bleeding. The arterial wall was then exposed with a spatula-type electric cautery down to the left colic artery (LCA). The LCA was then clipped and cut while preserving the SRA. The inferior mesenteric vein was divided at the caudal side of the LCA and prior to joining to the splenic vein. All cases underwent a LN dissection laparoscopically. There were no cases of complications originating from the LN dissection. Although long-term outcomes should be investigated, our results indicate that this is a safe, applicable method.

Anatomical variations of the coeliac trunk and the mesenteric arteries evaluated with 64-row CT angiography

PURPOSE

This study was undertaken to evaluate the accuracy of 64-row computed tomography angiography (CTA) in the study of vascular anatomy by assessing the incidence of anatomical variations of the origin of the coeliac trunk, mesenteric arteries and collateral branches.

MATERIALS AND METHODS

Sixty patients were evaluated with 64-row CTA (VCT, General Electric Healthcare, Milwaukee, WI, USA) with a collimation of 0.625 mm after the injection of iodinated nonionic contrast material (4 ml/s). Exclusion criteria were the presence of any pathological condition likely to affect normal vascular anatomy.

RESULTS

The coeliac trunk had a normal trifurcation in 56.7% of cases. The common hepatic artery was normal in 60% of patients. The inferior pancreaticoduodenal arteries were either absent or not assessable in 8.3% of cases and there was a double trunk in 5%, a common trunk in 83.3% and a single vessel in 3.3%. The number of jejunal and ileal arteries ranged from a minimum of six to a maximum of 13 (mean value 8.7+/-1.34). The Riolan arcade was assessable in 31.7% and developed in 68.4% of these.

CONCLUSIONS

The 64-row CTA enables visualisation of small vessels and accessory arteries that are difficult to identify with other techniques. The technique's high sensitivity allowed us to observe that the prevalence of vascular abnormalities is higher than that reported in the literature.

Applied vascular anatomy of the colon and rectum: clinical implications for the surgical oncologist

Surgery remains the most radical method of treatment of many solid tumors, including colorectal cancer; in these tumors, surgery is the only method that can offer the chance of cure. To avoid early postoperative morbidity (mainly, anastomotic leak) and to achieve good long-term results (low incidence of tumor recurrence, long overall and disease-free survival, and optimal quality of life), the surgeon should have an in-depth knowledge of vascular anatomy of the colon and rectum. This essential requirement is based on the fact that the actual course followed by lymph fluid drainage from any part of the colon/rectum is determined by its blood supply; therefore, the extent of resection for colorectal cancer follows the principles of blood supply and lymphatic drainage. Knowledge of the colorectal vascular anatomy and its variations is of vital importance in the planning of radical surgical treatment and in appropriately performing colorectal resections, particularly in the patient who underwent in the past colectomy or aortic surgery that has changed the usual pattern of collateral blood supply to the colon. This review summarizes currently available data regarding vascular anatomy of the colon and rectum, from a surgical perspective.

Ischemic Proctitis: Case Series and Literature Review

Ischemic injury to the rectum is rare owing to its rich vascular supply, and is seldom seen in clinical practice. Risk factors include major vascular occlusive disease, disruption of collateral circulation, and low flow state. It is of paramount importance to diagnose this entity early in its course. Although CT scan can suggest the diagnosis and identify other causes of clinical deterioration, colonoscopy remains the key test in diagnosing and determining the extent of ischemic change. Endoscopic findings and the overall clinical picture determine patient management. Treatment is nonoperative for nongangrenous ischemic proctocolitis, whereas surgery is necessary for gangrenous, transmural rectal ischemia. Over a 20-year period, a retrospective review of cases of acute rectal ischemia were analyzed. Aortoiliac occlusive disease accounted for nearly one-half the cases (7/15), and 40 per cent (6/15) was secondary to a low flow state. In our series, two-thirds of the cases involved transmural necrosis of the rectal wall (40% mortality) and the remaining one-third presented with patchy ischemic changes (20% mortality).

Preoperative assessment of vascular anatomy of inferior mesenteric artery by volume-rendered 3D-CT for laparoscopic lymph node dissection with left colic artery preservation in lower sigmoid and rectal cancer

AIM: To determine the distance between the branching point of the left colic artery (LCA) and the inferior mesenteric artery (IMA) by computed tomography (CT) scanning, for preoperative evaluation before laparoscopic colorectal operation.

METHODS: From February 2004 to May 2005, 100 patients (63 men, 37 women) underwent angiography performed with a 16-scanner multi-detector row CT unit (Toshiba, Aquilion 16). All images were analyzed on a workstation (AZE Ltd, Virtual Place Advance 300). The distance from the root of the IMA to the bifurcation of the LCA was measured by curved multi-planar reconstruction on a workstation.

RESULTS: The IMA could be visualized in all the cases, but the LCA was missing in two patients. The mean distance from the root of the IMA to the root of the LCA was 42.0 mm (range, 23.2-75.0 mm). There were no differences in gender, arterial branching types, body weight, height, and body mass index.

CONCLUSION: Volume-rendered 3D-CT is helpful to assess the vascular branching anatomy for laparoscopic surgery.

Laparoscopic lymph node dissection around the inferior mesenteric artery for cancer in the lower sigmoid colon and rectum: is D3 lymph node dissection with preservation of the left colic artery feasible?

BACKGROUND

When we perform laparoscopic lymph node dissection around the inferior mesenteric artery (IMA), we preserve the left colic artery (LCA) to maintain the blood supply to the proximal sigmoid colon. In this study, we present our laparoscopic D2 and D3 lymph node (LN) dissection technique and evaluate its applicability and safety.

METHODS

We performed LN dissection on 23 rectal and lower sigmoid colon cancer cases from April 2002 to December 2004. For D3 LN dissection, the incision to the mesosigmoid extends to just before the root of the IMA, which is exposed with an ultrasonic cutting and coagulating surgical device to avoid bleeding. Then, the arterial wall is exposed with a dissecting electrocautery spatula down to the LCA, at least 2 cm of which is exposed. Adipose tissue surrounding the IMA and inferior mesenteric vein is dissected. For D2 LN dissection, we partially expose the IMA to confirm the location of the LCA.

RESULTS

The mean times taken for D2 and D3 LN dissections were 36.2 and 68.2 min, respectively. Both procedures took longer in male patients. There was a trend for the procedure overall to take less time in female patients. However, D2 dissection took significantly longer in male than female patients (p < 0.05). In women, D3 dissection took significantly longer than D2 (p < 0.05), but this trend was not seen in men. Increased experience among surgeons with this procedure was associated with significantly faster LN dissections in men (p < 0.05), but not in women (p = 0.493). Pearson product moment analysis identified a relationship between body mass index (BMI) and the time taken for D2 LN dissection (r = 0.765), but not D3 LN dissection (r = 0.158). There was no treatment-related morbidity with this technique.

CONCLUSIONS

This method was safe and feasible for all patients in this series, but takes longer to perform in male patients.

Review article: diagnosis and management of mesenteric ischaemia with an emphasis on pharmacotherapy

Mesenteric ischaemia results from decreased blood flow to the bowel, causing cellular injury from lack of oxygen and nutrients. Acute mesenteric ischaemia (AMI) is an uncommon disorder with high morbidity and mortality, but outcomes are improved with prompt recognition and aggressive treatment. Five subgroups of AMI have been identified, with superior mesenteric artery embolism (SMAE) the most common. Older age and cardiovascular disease are common risk factors for AMI, excepting acute mesenteric venous thrombosis (AMVT), which affects younger patients with hypercoaguable states. AMI is characterized by sudden onset of abdominal pain; a benign abdominal exam may be observed prior to bowel infarction. Conventional angiography and more recently, computed tomography angiography, are the cornerstones of diagnosis. Correction of predisposing conditions, volume resuscitation and antibiotic treatment are standard treatments for AMI, and surgery is mandated in the setting of peritoneal signs. Intra-arterial vasodilators are used routinely in the treatment of non-occlusive mesenteric ischaemia (NOMI) and also are advocated in the treatment of occlusive AMI to decrease associated vasospasm. Thrombolytics have been used on a limited basis to treat occlusive AMI. A variety of agents have been studied in animal models to treat reperfusion injury, which sometimes can be more harmful than ischaemic injury. Chronic mesenteric ischaemia (CMI) usually is caused by severe obstructive atherosclerotic disease of two or more splanchnic vessels, presents with post-prandial pain and weight loss, and is treated by either surgical revascularization or percutaneous angioplasty and stenting.

Multislice CT angiography of mesenteric vessels

Due to several distinct advantages over conventional angiography (including minimal invasiveness, lower cost, and lower ionizing radiation exposure for patients and staff), computed tomography (CT) angiography has replaced diagnostic conventional angiography in several clinical situations. The recent introduction of multislice CT (MSCT) scanners has significantly improved CT angiographic applications, especially in the evaluation of the mesenteric vasculature. Thin-slice collimation protocols associated with powerful postprocessing procedures allow the display of mesenteric circulation with excellent detail. The purposes of this presentation are (a) to illustrate the imaging technique that can be used to obtain state-of-the-art MSCT angiographic images of the mesenteric vasculature, (b) to review the normal anatomy and anatomic variants of mesenteric vessels, and (c) to illustrate some of the potential clinical applications of MSCT angiography of the mesenteric vessels.

Intestinal ischemia

Ischemic injury to the gastrointestinal tract can threaten bowel viability with potential catastrophic consequences, including intestinal necrosis and gangrene. The presenting symptoms and signs are relatively nonspecific and diagnosis requires a high index of clinical suspicion. AMI often results from an embolus or thrombus within the SMA, although a low-flow state through an area of profound atherosclerosis may also induce severe ischemia. Because most laboratory and radiologic studies are nonspecific in early ischemia an aggressive approach to diagnosis with imaging of the splanchnic vasculature by mesenteric angiography is advocated. Various therapeutic approaches, including the infusion of vasodilators and thrombolytics, may then be used. Proper diagnosis and management of patients with AMI requires vigilance and a readiness to pursue an aggressive course of action.

Collateral pathways in patients with celiac axis stenosis: angiographic-spiral CT correlation

Although celiac axis stenosis is a frequently encountered occlusive vascular disease, clinically significant ischemic bowel disease caused by celiac axis stenosis is rarely reported due to rich collateral circulation from the superior mesenteric artery (SMA). The most important and frequently encountered collateral vessels from the SMA in patients with celiac axis stenosis are the pancreaticoduodenal arcades and the dorsal pancreatic artery. Subtypes of collateral pathways via the dorsal pancreatic artery include a longitudinal pathway between the celiac branches and the SMA or its branches and a transverse pathway to either the splenic or gastroduodenal artery. A communicating channel between the right hepatic artery and the SMA can be a route for collateral circulation. Hepatic artery variants cause the development of unique collateral pathways that have different characteristics depending on the type of variant. These collateral pathways include intrahepatic interlobar collateral vessels, right gastric to left gastric arterial anastomoses, left hepatic to left gastric arterial anastomoses, and peribiliary arterial plexuses. Major collateral pathways in patients with celiac axis stenosis can be identified with spiral CT, and knowledge concerning this collateral circulation may be important for certain medical procedures such as interventional procedures for the management of hepatic tumors, pancreaticobiliary surgery, and liver transplantation.

Volume-rendered 3D CT of the mesenteric vasculature: normal anatomy, anatomic variants, and pathologic conditions

Multi-detector row computed tomography (CT) offers important advantages over more conventional imaging methods in the evaluation of the mesenteric vasculature. It allows faster scanning, which practically eliminates motion and breathing artifacts, as well as thinner collimation. These advances, coupled with rapid intravenous administration of contrast material, allow excellent opacification of the mesenteric arteries and veins. This improves the quality of the three-dimensional (3D) data sets, which in turn leads to improved 3D vascular maps and more accurate assessment of various conditions such as arterial or venous encasement in patients with pancreatic cancer, mesenteric ischemia, or inflammatory bowel disease. Three-dimensional multi-detector row CT also allows better visualization of arterial and venous branching, thereby improving detection of more distal vascular involvement. In addition, 3D multi-detector row CT may help detect hemodynamic changes in patients with active inflammation and hyperemia of a bowel segment because it can be used to measure bowel wall enhancement over time. Carcinoid tumors that have infiltrated the mesentery have a characteristic CT appearance, and other conditions such as lymphoma or sclerosing mesenteritis can also manifest as an infiltrating mass that envelops mesenteric vessels. Three-dimensional multi-detector row CT represents a significant advance in CT technology and can help ensure prompt, accurate evaluation of the mesenteric vasculature.

Chronic splanchnic ischaemia

Chronic splanchnic ischaemia is a relatively unusual clinical entity consisting of pain and/or weight loss and caused by chronic splanchnic disease (i.e. stenosis and/or occlusion of the coeliac and superior mesenteric artery). The occlusive disease is usually caused by atherosclerosis and is in itself not rare in older individuals. Extensive collateral circulation can develop between the three splanchnic arteries and may compensate for the decreased splanchnic perfusion over time. The pathophysiology of chronic splanchnic ischaemia has still not been completely elucidated.A reliable diagnosis of chronic splanchnic ischaemia, based on a proven causal relationship between the occlusive disease and the symptoms, can be very difficult. Traditionally, tests for evaluating the haemodynamic consequences of the vascular stenoses were not available. Important improvements in establishing a more reliable diagnosis have been achieved with duplex ultrasound and magnetic resonance evaluation of the splanchnic circulation. Tonometry is another promising functional test that may prove useful not only for gaining greater insight into the pathophysiology of chronic splanchnic ischaemia but also for the clinical evaluation of this syndrome. The natural history of chronic splanchnic disease suggests that progressive disease may result in acute mesenteric ischaemia. Surgical reconstruction of the coeliac and/or the superior mesenteric artery is the therapeutic standard with excellent short and long-term results. Satisfactory early results using angioplasty with or without stent suggest that this type of intervention may relieve symptoms in selected patients with a higher surgical risk.

Vascular anatomy of the gastrointestinal tract

The blood supply of the gastrointestinal system has intramural and extramural components. The intramural vascular distribution is generally well developed with plexuses in the different layers of the bowel wall and with specializations in the liver, small intestine and gastroesophageal junction, adapted to the function of these organs. The extramural arterial supply for the oesophagus is derived from the thoracic aorta or its major branches. Blood supply to the abdominal organs is provided by three major unpaired vessels arising from the abdominal aorta, namely the coeliac trunk and the superior and inferior mesenteric arteries. The branches of these vessels form anastomotic systems that provide a rich blood supply to the adjoining organs. In many areas the systems overlap while in other regions linkages are limited. Interrelations and weak points are of significant clinical importance. As well as this, there is a great individual variability in the anatomy of the gastrointestinal vasculature.

Embryology, anatomy, and surgical exposure of the great abdominal vessels

This article describes the embryology of the abdominal aorta and the anatomic features of its major visceral branches, including the celiac, superior mesenteric, and inferior mesenteric arteries. The common anatomic variants of these visceral vessels also are reviewed. Various operative techniques to gain surgical exposure to these vessels are described.

Mesenteric, coeliac and splanchnic blood flow in humans during exercise

1. Exercise reduces splanchnic blood flow, but the mesenteric contribution to this response is uncertain. 2. In nineteen humans, superior mesenteric and coeliac artery flows were determined by duplex ultrasonography during fasting and postprandial submaximal cycling and compared with the splanchnic blood flow as assessed by the Indocyanine Green dye-elimination technique. 3. Cycling increased arterial pressure, heart rate and cardiac output, while it reduced total vascular resistance. These responses were not altered in the postprandial state. During fasting, cycling increased mesenteric, coeliac and splanchnic resistances by 76, 165 and 126 %, respectively, and it reduced corresponding blood flows by 32, 50 and 43 % (by 0.18 +/- 0.04, 0.42 +/- 0.03 and 0.60 +/- 0.04 l min-1). Postprandially, mesenteric and splanchnic vascular resistances decreased, thereby elevating regional blood flow, while the coeliac circulation was not influenced. Postprandial cycling did not influence the mesenteric resistance significantly, but its blood flow decreased by 22 % (0.46 +/- 0.28 l min-1). Coeliac and splanchnic resistance increased by 150 and 63 %, respectively, and the corresponding regional blood flow decreased by 51 and 31 % (0.49 +/- 0.07 and 0.96 +/- 0.28 l min-1). Splanchnic blood flow values assessed by duplex ultrasound and by dye-elimination techniques were correlated (r = 0.70; P < 0.01). 4. During submaximal exercise in humans, splanchnic resistance increases and blood flow is reduced following a 50 % reduction in the hepato-splenic and a 25 % reduction in the mesenteric blood flow.

Intestinal (mesenteric) vasculopathy. I. Acute superior mesenteric arteriopathy and venopathy

Intestinal vasculopathy is not rare, comprising about 1 per 1000 hospital admissions. Primary mesenteric vasculopathy causes cardiovascular disease, whereas secondary mesenteric ischemia causes extrinsic vascular compression or vascular trauma. Acute superior mesenteric arteriopathy is caused by a mesenteric embolus, thrombus, or vasospasm (i.e., nonocclusive vasculopathy). Acute superior mesenteric venopathy is caused by a thrombus, which is often associated with a hypercoagulopathy. The clinical presentation of both diseases is often subtle and nonspecific at an early stage and becomes overt and specific only when advanced and severe, when ischemia progresses to necrosis. The mortality of acute superior mesenteric arteriopathy is still very high, whereas superior mesenteric venopathy is less rapidly progressive and has a lower, but still significant, mortality. Early diagnosis and aggressive therapy significantly reduces the mortality of these life-threatening diseases.

The mesenteric circulation. Anatomy and physiology

The purpose of this article is to review the angiographic appearance of the major visceral arteries, the more common variants, their embryologic origins, and some of the most common sources of collateral flow. A brief review of the physiology of the mesenteric circulation is also provided, including a discussion of the intrinsic and extrinsic mechanisms of splanchnic blood flow control.

History of mesenteric ischemia. The evolution of a diagnosis and management

This article has traced the evolution of our knowledge of mesenteric ischemia from the initial stage of recognition of the condition and its manifestations, through the phase of treatment after the fact-resection of gangrenous intestine, to our present-day attempts to diagnose and treat the ischemic episode before death of the bowel and patient occurs. It is history from the authors' perspective, and because of limitations of space it is, perforce, highly selective. Hundreds of valuable contributions could not be included, and their omission in no way detracts from their importance. A number of surgeons, including Williams and Bergen in this country, Marston in England, Saegesser in Switzerland, and Kieny in France, have made mesenteric ischemia a major focus of their careers and have published extensively on it. The first book devoted to all aspects of mesenteric ischemia, Vascular Disorders of the Intestines edited by Boley, Schwartz, and Williams, was published in 1971. Since that time a number of books and monographs have chronicled progress in the field. Together these references make a good foundation for newly interested investigators in the subject. The results of diagnosis and management of mesenteric ischemia have improved significantly over the past 100 years but remain poor. The best part of the history of mesenteric ischemia remains to be written.

Right colonic arterial anatomy. Implications for laparoscopic surgery

PURPOSE

Hemorrhagic complications can be a major cause of conversion and/or morbidity during laparoscopic intestinal surgery. The limited exposure currently provided in laparoscopic intestinal resection demands a precise knowledge of mesenteric vascular anatomy to avoid such complications and to expedite the procedure. Most surgical texts depict a "normal pattern" of arterial supply to the right colon consisting of three arterial branches (ileocolic artery, right colic artery, and middle colic artery) arising independently from the superior mesenteric artery (SMA). Based on previous reports and clinical observations, we hypothesized that the right colic artery arises infrequently from the SMA, and most commonly, there are only two colonic arteries arising independently from the SMA.

METHODS

We performed detailed dissections of the SMA in 56 human cadavers.

RESULTS

We found the ileocolic artery in all of our cases and the middle colic artery in 55 of 56 cadavers but only six cases of a right colic artery emanating directly from SMA.

CONCLUSIONS

Our data, combined with review of published anatomic studies, lead us to conclude that in the vast majority of cases there are only two independent branches arising from SMA that supply the large intestine, the ileocolic and the middle colic arteries. The right colic artery directly arising from SMA is unusual (10.7 percent). This knowledge may help lower the risk of vascular complications during laparoscopic intestinal surgery.

Colorectal carcinoma metastases to the liver. Does primary tumor location affect its lobar distribution?

BACKGROUND

There is considerable evidence that blood returning from different abdominal organs does not mix completely but maintains streamline flow in the portal vein. This study tested the hypothesis that the location of primary colorectal carcinoma affects the intrahepatic distribution of liver metastases according to streamline flow in the portal vein.

METHODS

Eighty-five patients with histologically verified liver metastases from colorectal carcinoma underwent potentially curative hepatectomy. Primary tumor location was the right-sided colon in 18 patients and the left-sided colon in 67. The liver was divided into two lobes by Cantlie's line.

RESULTS

A total of 195 metastatic deposits were resected: 135 in the right lobe and 60 in the left. In the right-sided colon carcinoma group, 29 deposits were in the right lobe and 3 in the left. In the left-sided colon carcinoma group, 106 deposits were in the right lobe and 57 in the left. The pattern of lobar distribution was significantly different in the two groups (P = 0.003).

CONCLUSIONS

Right-sided colon cancers selectively involve the right lobe, while left-sided tumors involve the entire liver, considering the ratio of weights of the right to left lobe is 2:1. This difference suggests that primary tumor location affects the pattern of lobar distribution of colorectal carcinoma liver metastases according to streamline flow in the portal vein.

Ischemic colitis

Ischemic colitis represents the most common form of gastrointestinal ischemia. The presumed etiologies are numerous; however, it typically develops "spontaneously," in the absence of major vasculature occlusion, and in the presence of viable intestine elsewhere. It is most usefully classified into gangrenous and nongangrenous forms, the latter of which may be subdivided into transient and chronic types. Ischemic colitis may develop in people who are otherwise healthy, although a variety of clinical settings, such as shock, predispose to its occurrence. It usually presents as an acute abdominal illness with bloody diarrhea. Diagnosis is confirmed by colonoscopy. Therapy and outcome are dependent on the severity of disease. Nongangrenous colonic ischemia usually requires only medical management and is associated with a good prognosis. The chronic subtype may lead to the sequelae of persistent segmental colitis or colonic strictures, occasionally requiring surgery. Urgent operative intervention and a high morbidity and mortality are the hallmarks of gangrenous colonic ischemia. Special considerations must be given to those patients in whom ischemic colitis develops in the context of colon carcinoma or obstructing colon lesions, after abdominal aortic surgery, and following cardiopulmonary bypass. This review will discuss the clinical spectrum of ischemic colitis.

Mesenteric ischemia. Acute arterial syndromes

Acute mesenteric ischemia represents one to two percent of all gastrointestinal illnesses. There are three possible causes of acute arterial mesenteric ischemia: embolism, thrombosis, and nonocclusive mesenteric insufficiency. The key to early diagnosis is a high index of suspicion. The classic clinical picture of obvious cardiac disease, sudden onset of severe abdominal pain and gastrointestinal emptying, is not always present. Serum markers and plain films are often nondiagnostic but may suggest acute arterial mesenteric ischemia. Angiography establishes the diagnosis and allows for planning of aortomesenteric bypass, if indicated. Papaverine is immediately instilled to decrease splanchnic vasoconstriction. Embolic and thrombotic disease is treated by laparotomy with re-establishment of visceral perfusion. Only after blood flow is restored is nonviable bowel resected. Clinical methods of assessing intestinal viability include Doppler scanning, intravascular dyes, and tissue oximetry. The decision to perform a second-look laparotomy is made prior to closure of the abdomen. Pharmacologic treatment is the mainstay of nonocclusive ischemia. Surgery is reserved for clinical deterioration. Survival is dependent on the cause and extent of occlusion as well as the rapidity of diagnosis and therapy. Bowel necrosis results in mortality rates between 80 percent and 95 percent.