A tale of two twists: mesentero-axial and organo-axial sigmoid volvulus.

INTRODUCTION: Sigmoid volvulus is a potentially devastating and life-threatening condition associated with sigmoid colon redundancy. Many of the classical radiological signs are considered to represent the two adjacent loops of bowel in a mesentero-axial volvulus. However, limited case reports and series have reported on an organo-axial subtype of sigmoid volvulus. This clinical entity is not widely understood. In this study, we assess the radiological and clinical features of mesentero-axial and organo-axial sigmoid volvulus. METHODS: After institutional board approval (CH62/6/2016-228), all computed tomography (CT) studies from 2011 to 2017 reported as sigmoid volvulus at a single institution were reviewed. The cases were reviewed by three radiologists retrospectively and the course of the bowel followed with a focus on assessing its rotational axis. In each case, the sigmoid volvulus was independently subclassified as mesentero-axial or organo-axial volvulus based on the axis of rotation of the volvulus. In addition, X-ray signs including disproportionate sigmoid dilatation, distended inverted 'U' in sigmoid, coffee bean sign, opposed wall sign, direction of apex of sigmoid loop, liver overlap sign, northern exposure sign and proximal colonic dilatation and CT features including whirl sign, 'X' marks the spot sign, split wall sign and number of transition points were reported for each case. The clinical management and outcomes including morbidity, mortality, endoscopic decompression and need for surgery were also evaluated. The subtype of volvulus was correlated with the above X-ray signs, CT features and clinical management and outcomes. Statistical analysis was conducted using Stata/MP, version 15 (StataCorp LP, College Station, TX, USA). RESULTS: A total of 38 scans were reviewed. There were 19 patients identified. Of these, six (32%) were reported as mesentero-axial and 13 (68%) as organo-axial volvulus. No X-ray signs were able to distinguish the two types of volvulus. The number of transition points on CT was predictive of volvulus subtype (OR 25, 95% CI: 1.30-1295.30, P = 0.01). Within the limitations of a small cohort, there was no statistically significant difference in unsuccessful endoscopic decompression, need for colectomy, repeated admissions or mortality between the groups. CONCLUSION: This study has demonstrated that organo-axial sigmoid volvulus may be as common as mesentero-axial volvulus. Distinguishing organo-axial from mesentero-axial volvulus can be achieved on CT, but not on abdominal X-ray. The number of transition points (two for mesentero-axial and one for organo-axial) may be used as a diagnostic feature for differentiating the two forms of volvulus.

3D mesenteric angiogram-based assessment of Arc of Riolan crossing the inferior mesenteric vein: important considerations in high ligation during splenic flexure takedown in anterior resection.

BACKGROUND: Recent studies have described the finding of the Arc of Riolan (AoR) crossing the inferior mesenteric vein (IMV) seen during high ligation of IMV while performing minimally invasive colectomies. However, the AoR usually has a medial course, and this variant AoR anatomic course and the clinical importance of its preservation during splenic flexure takedown in anterior resection remains controversial. METHODS: After institutional approval (QA-5775), radiological identification of and mapping of the vessel horizontally crossing the IMV under the pancreas, when present, was performed at a single institution (Westmead Hospital, New South Wales, Australia). One hundred consecutive computed tomographic (CT) mesenteric angiograms conducted in 2018 were reviewed retrospectively to determine the presence of a vessel horizontally crossing the IMV. 3D reconstructions were used to map out its course to understand its origin and full course. Baseline characteristics, including demographic and comorbidity data, were obtained from the medical record. RESULTS: On 3D mesenteric angiogram reconstructions, a vessel crossing anterior to the IMV was present in 11 of 98 cases (11.2%). Two cases were excluded as the presence of this vessel was indeterminate. Eight of 11 patients (72.7%) were male, and the mean age was 49.3 years (range: 21-80 years). There was no statistically significant difference in age and comorbidities between the groups. Importantly, in all 11 cases, there was an arterial vessel crossing the IMV originating from the SMA and communicating with the IMA or a branch of the IMA, proving definitively that this vessel was by definition the AoR. CONCLUSION: This 3D mesenteric angiogram mapping study has shown definitively that the vessel horizontally crossing anterior to the IMV and inferior to the pancreas is an arterial vessel from the SMA to IMA, and by definition the Arc of Riolan. When present, identification and preservation of this collateral arterial vessel during splenic flexure takedown in anterior resection may be important in reducing the risk of post-operative bowel ischaemia.

Attitudes towards Enhanced Recovery after Surgery (ERAS) interventions in colorectal surgery: nationwide survey of Australia and New Zealand colorectal surgeons.

BACKGROUND: Whilst Enhanced Recovery after Surgery (ERAS) has been widely accepted in the international colorectal surgery community, there remains significant variations in ERAS programme implementations, compliance rates and best practice recommendations in international guidelines. METHODS: A questionnaire was distributed to colorectal surgeons from Australia and New Zealand after ethics approval. It evaluated specialist attitudes towards the effectiveness of specific ERAS interventions in improving short term outcomes after colorectal surgery. The data were analysed using a rating scale and graded response model in item response theory (IRT) on Stata MP, version 15 (StataCorp LP, College Station, TX). RESULTS: Of 300 colorectal surgeons, 95 (31.7%) participated in the survey. Of eighteen ERAS interventions, this study identified eight strategies as most effective in improving ERAS programmes alongside early oral feeding and mobilisation. These included pre-operative iron infusion for anaemic patients (IRT score = 7.82 [95% CI: 6.01-9.16]), minimally invasive surgery (IRT score = 7.77 [95% CI: 5.96-9.07]), early in-dwelling catheter removal (IRT score = 7.69 [95% CI: 5.83-9.01]), pre-operative smoking cessation (IRT score = 7.68 [95% CI: 5.49-9.18]), pre-operative counselling (IRT score = 7.44 [95% CI: 5.58-8.88]), avoiding drains in colon surgery (IRT score = 7.37 [95% CI: 5.17-8.95]), avoiding nasogastric tubes (IRT score = 7.29 [95% CI: 5.32-8.8]) and early drain removal in rectal surgery (IRT score = 5.64 [95% CI: 3.49-7.66]). CONCLUSIONS: This survey has demonstrated the current attitudes of colorectal surgeons from Australia and New Zealand regarding ERAS interventions. Eight of the interventions assessed in this study including pre-operative iron infusion for anaemic patients, minimally invasive surgery, early in-dwelling catheter removal, pre-operative smoking cessation, pre-operative counselling, avoidance of drains in colon surgery, avoiding nasogastric tubes and early drain removal in rectal surgery should be considered an important part of colorectal ERAS programmes.