Effects of artificial ileocolonic sphincter on motility in intestinal remnant following subtotal small intestinal resection in the dog

Autologous Intestinal Reconstruction Surgery in Short Bowel Syndrome: Which, When, and Why

Short bowel syndrome (SBS), secondary to any natural loss or after any extensive bowel resection for congenital malformations or acquired disease, is the most common cause of intestinal failure in children. Extensive introduction of parenteral nutrition (PN) has dramatically changed the outcome of these patients, allowing for long-term survival. The main goal in children with SBS remains to be increasing enteral tolerance and weaning from PN support. Post resection intestinal adaptation allows for achievement of enteral autonomy in a subset of these patients, but the inability to progress in enteral tolerance exposes others to long-term complications of PN. Autologous intestinal reconstruction surgery (AIRS) can facilitate the fulfilment of enteral autonomy, maximizing the absorptive potential of the remaining gut. All the different intestinal reconstruction techniques, from simple procedures like tapering, reversed segments, and colon interposition, to more complex lengthening procedures (LILT: longitudinal intestinal lengthening and tailoring, STEP: serial transverse enteroplasty, and SILT: spiral intestinal lengthening and tailoring) and techniques designed for peculiar problems like controlled intestinal tissue expansion or duodenal lengthening are presented. AIRS indications, clinical applications, and results reported in the literature are reviewed.

Are right-sided colectomies for neoplastic disease at increased risk of primary postoperative ileus compared to left-sided colectomies? A coarsened exact matched analysis

INTRODUCTION

The objective of this study was to determine whether right-sided colectomies (RC) were associated with a higher incidence of primary postoperative ileus (pPOI) compared to left-sided colectomies (LC).

METHODS

Patients who underwent elective colectomy for neoplastic disease between 2012 and 2016 were identified using the American College of Surgeons National Surgical Quality Improvement Program database. RC and LC were defined as having an ileocolic or colocolic/colorectal anastomosis, respectively. Coarsened Exact Matching (CEM) was used to balance the two groups (1:1) on important confounders. The association between type of colectomy and pPOI, defined as POI in the absence of intra-abdominal sepsis, was then assessed in a multiple logistic regression analysis of the matched data.

RESULTS

Of 40,636 patients who underwent a colectomy for neoplastic disease, 15,231 underwent a RC and 25,405 a LC. After CEM, 12,949 matched patients remained in each group, and all important confounders were well balanced. The incidence of pPOI was higher in the RC group (11.5% vs. 8.8%, p < 0.001). On multiple logistic regression, RC was associated with a 35% higher odds of developing pPOI compared to LC (OR 1.35, 95% CI 1.25-1.47). RC was also associated with increased risk for NSQIP-defined major morbidity (OR 1.10, 95% CI 1.01-1.20), 30-day readmission (OR 1.16, 95% CI 1.06-1.27), and increased length of stay (β = 0.16 days, 95% CI 0.11-0.22).

CONCLUSION

pPOI is more common after RC than LC. Future research should aim at better understanding the pathophysiology behind this increased risk and identifying interventions to mitigate pPOI in this population.

Congenital Short-Bowel Syndrome in an Adult Dog

A 3.5-year-old, neutered male pit bull dog was euthanized following an approximately 1-year history of intractable diarrhea and weight loss of undetermined cause. At necropsy, the dog was emaciated. The ratio of total intestinal length (duodenum to rectum) to crown-to-rump length was 2.5, in contrast to an average of 5.3 (range, 3.7-6.1) in 10 control dogs examined at necropsy. There was diffuse dilation of the intestinal lumen, consistent with congenital intestinal hypoplasia resulting in short-bowel syndrome. Histologically, the intestinal mucosal was hyperplastic, further supporting the diagnosis of short-bowel syndrome. To the authors' knowledge, this is the first case of this condition in the veterinary literature.

Isoperistaltic versus antiperistaltic side-to-side anastomosis after right laparoscopic hemicolectomy for cancer (ISOVANTI) trial: study protocol for a randomised clinical trial

BACKGROUND

It is believed that loosing ileocecal valve is well tolerated in patients who do not have short bowel syndrome or Crohn disease. From the hypothesis of colonic peristalsis and transit is regulated by that ileocecal valvular mechanism, we try to find out if the creation of a new pseudo-valvular mechanism as antiperistaltic anastomosis could be considered after right hemicolectomy can cause any short- or long-term changes in gastrointestinal habits.

PURPOSE

The purpose of the study at primary endpoint is to compare early (occurring within 30 days of surgery) and late (occurring during the follow-up) postoperative complications between both groups The purpose of the study at secondary endpoint is to compare intraoperative and postoperative events between experimental and control groups in terms of operating time, first oral tolerance day, first flatus and faeces, length of hospital stay and orocecal transit; comparing rates of gastrointestinal life quality and comparing mortality rates between both groups.

METHODS

The ISOVANTI trial is a randomized controlled single-centre trial comparing isoperistaltic versus antiperistaltic side-to-side anastomosis after right laparoscopic hemicolectomy. It is designed as a parallel group superiority trial.

CONCLUSIONS

It is unknown if a pseudo-valvular mechanism as antiperistaltic anastomosis can be considered has short- or long-term consequences in gastrointestinal habit. Considering the impact that ileocolic anastomosis configuration could have on the restitution of bowel transit after right hemicolectomy, we think it is indicated and necessary a randomized trial comparing iso- and antiperistaltic modalities.

TRIAL REGISTRATION

NCT02309931.

Effects of aging on the architecture of the ileocecal junction in rats

AIM: To evaluate the structural organization of the elastic and collagen fibers in the region of the ileocecal transition in 30 young and old male Wistar rats.

METHODS: Histology, immunohistochemistry (IHC), transmission electron microscopy and scanning electron microscopy were employed in this study. The results demonstrated that there was a demarcation of the ileocecal region between the ileum and the cecum in both groups.

RESULTS: The connective tissue fibers had different distribution patterns in the two groups. IHC revealed the presence of nitric oxide synthase, enteric neurons and smooth muscle fibers in the ileocecal junctions (ICJs) of both groups. Compared to the young group, the elderly group exhibited an increase in collagen type I fibers, a decrease in collagen type III fibers, a decreased linear density of oxytalan elastic fibers, and a greater linear density of elaunin and mature elastic fibers.

CONCLUSION: The results revealed changes in the patterns of distribution of collagen and elastic fibers that may lead to a possible decrease in ICJ functionality.

Enteroenteroanastomosis near adjacent ileocecal valve in infants

AIM: To investigate the feasibility and the effectiveness of ileoileostomy in the region adjacent to the ileocecal valve, which can retain the ileocecal valve in infants.

METHODS: This is a retrospective review of 48 patients who underwent ileoileostomy in the region adjacent to the ileocecal valve (group 1) and 34 patients who underwent ileocecal resections and ileotransversanastomosis (group 2). Patients were monitored for the time to flatus, resumption of eating, length of hospital stay after surgery, serum total bile acid, vitamin B12 and postoperative complications.

RESULTS: The time to flatus, time until resumption of eating and post-operative length of hospital stay showed no statistically significant differences between the two groups. Serum total bile acid and vitamin B12 were not significantly different between the two groups at post-operative day 1 and day 3, but were significantly decreased at 1 wk after operation in group 2. None of the patients died or suffered from stomal leak in these two groups. However, the incidence of diarrhea, intestinal infection, disturbance of acid-base balance and water-electrolytes in group 1 was lower than in group 2.

CONCLUSION: Ileoileostomy in the region adjacent to the ileocecal valve is safe and results in fewer complications than ileotransversanastomosis in infants.

Autologous gastrointestinal reconstruction: review of the optimal nontransplant surgical options for adults and children with short bowel syndrome

Short bowel syndrome (SBS) results in loss of absorptive capacity of the development of gut, leading to malabsorption due to protein, energy, fluid, and electrolyte loss and imbalance while on enteral diet alone. Various nonsurgical and surgical therapeutic options that have emerged improve the survival outcome following SBS in both children and adults. An individualized, complex multidisciplinary approach to medical and surgical intestinal rehabilitation is needed to provide an opportunity for enteral autonomy to be possible in a patient with SBS. The remnant bowel plays a very pivotal role in autologous gastrointestinal reconstruction (AGIR) surgery. Intestinal transplantation, although promising and potentially life-saving for SBS, should be reserved for patients with failed AGIR or those who have no prospect for autologous enteral autonomy. This article reviews the evolution of nontransplant surgical management of patients with SBS.

Ileocaecal valve: how important is it?

PURPOSE

Our aim was to investigate the importance of the ileocaecal valve and its reconstruction in patients that are not suffering from short bowel syndrome and Crohn's disease.

METHODS

Casenotes of 99 children with hemicolectomy and 24 children with terminal ileal resection were reviewed and sorted into three groups. Group 1: ileocaecal valve resection (limited hemicolectomy), Group 2: hemicolectomy, Group 3: terminal ileal resection between 10 and 25 cm. Patients with Crohn's, short bowel syndrome and incomplete follow-up were excluded.

RESULTS

Chronic diarrhoea was documented in 7/26 cases (27%) in Group 1, 6/23 patients (26%) in Group 2, and none of the 13 patients had diarrhoea in Group 3. Pearson Chi-square test showed significant difference between Group 1 and Group 3 (p = 0.038) and between Group 2 and Group 3 (p = 0.043). But there was no significant difference between Group 1 and Group 2 (p = 0.947).

CONCLUSION

Chronic diarrhoea is a significant complication after limited hemicolectomy not only in Crohn's disease and short bowel syndrome. This is likely to originate from the loss of the ileocaecal valve itself rather than the loss of the ileal or colonic segment. Our results justify attempts to reconstruct the ileocaecal valve.

New insights into the neuromuscular anatomy of the ileocecal valve

The neuroanatomy of the ileocecal valve (ICV) is poorly understood. A better understanding of this important functional component of the gastrointestinal tract would enable surgeons to reconstruct an effective valve following surgical resection of the ICV. ICVs were examined in young pigs (N = 5) using frontal and transverse paraffin embedded and frozen sections. Hematoxylin+Eosin (H+E) staining, acetylcholinesterase (AchE), and NADPH-diaphorase (NADPH-d) histochemistry and protein gene product 9.5 (PGP 9.5) and C-kit immunohistochemistry were performed. The H+E staining revealed that the ICV consists of three muscle layers: an external circular muscle layer continuous with that of the ileal circular muscle layer, an inner circular muscle layer continuous with that of the cecal circular muscle layer, and a single longitudinal muscle layer, which appears to be secondary to a fusion of the ileal and cecal longitudinal muscle layers. The AchE, NADPH-d, and PGP 9.5 staining revealed two distinct coaxial myenteric plexuses, together with superficial and deep submucosal plexuses. The C-kit immunostaining showed a continuous myenteric ICC network within the ICV. The structure of the neuromuscular components within the ICV suggests that the valve is a result of a simple intussusception of the terminal ileum into the cecum. This knowledge may help surgeons in their future attempts at reconstructing more anatomically and functionally suitable ICVs following surgical resection of native ICVs.

Hydrostatic characteristics of the ileocolic valve and intussuscepted nipple valves: an animal model

The ileocolic valve, in the dog, decelerates the passage of stools and prevents fecal reflux. A loss of anterograde resistance worsens the symptoms of short bowel syndrome. The absence of fecal reflux control enhances the risk of recurrence of Crohn's disease. The aim of the present study was to examine what length of intussusception-like nipple valve (INV) should be constructed in order to restore the hydrostatic characteristics of the normal ileocecal valve. The anterograde and retrograde hydrostatic resistances of INVs of different lengths (4, 5, 6, or 7 cm) were compared with those of the normal ileocolic valve by using a contrast enema and x-ray monitoring in a canine model. It was found that the 4-cm-long INV may be sufficient to achieve an appropriate antireflux efficacy (59.60 +/- 4.26 cm H(2)O) versus the ileocolic valve (25.80 +/- 4.92 cm H(2)O), but this does not furnish an anterograde resistance comparable to that of the normal ileocolic valve (10.70 +/- 1.15 cm H(2)O vs. 21.60 +/- 3.96 cm H(2)O). We found that the appropriate length of the INV with which the anterograde resistance of the ileocolic valve could be attained in our model was between 6 and 7 cm. Thus, the shortest possible constructed INV should be effective in clinical conditions such as Crohn's disease, but the recommended length in short bowel syndrome should be greater than this.

Ileal resection enhances jejunal absorptive adaptation for water and electrolytes to extrinsic denervation: implications for segmental small bowel transplantation

BACKGROUND/PURPOSE

Segmental small bowel transplantation (SBT) may be an alternative to whole jejunoileal SBT. The aim of this study was to evaluate adaptability of extrinsically denervated jejunum after ileectomy.

METHODS

Baseline absorption of an isomolar, nonnutrient electrolyte solution was measured in an 80-cm in situ jejunal segment. Control (CON) and extrinsically denervated dogs (EXT DEN) then underwent distal 50% enterectomy; EXT DEN dogs also underwent a complete extrinsic denervation of remnant jejunum. Absorption was remeasured 2 and 12 weeks later; jejunal biopsies at 12 weeks were compared with baseline.

RESULTS

All dogs experienced weight loss and diarrhea, which resolved by 10 weeks in CON but persisted in EXT DEN dogs. Net absorptive fluxes of water, Na+, K+, and Cl-, however, remained unchanged in both groups 2 weeks and 12 weeks after denervation. Morphometric evaluation showed an increase in crypt depth in both groups at the 12-week time-point.

CONCLUSIONS

Despite a clinical short bowel syndrome, more weight loss, and diarrhea in EXT DEN, there were no temporal differences in net absorptive fluxes of water and electrolytes within or between these 2 groups, and both developed increased crypt depth at 12 weeks. Extrinsic denervation does not blunt jejunal adaptive response to ileectomy.

Role of extrinsic innervation in jejunal absorptive adaptation to subtotal small bowel resection: a model of segmental small bowel transplantation

Segmental small bowel transplantation offers theoretic advantages over total jejunoileal transplantation, but the regional ability of the transplanted segment to adapt is unknown. Absorption was measured in an 80 cm jejunal segment via a triple-lumen perfusion technique. Separate experiments measuring absorption of four nutrients (glucose, glutamine, oleic acid, and taurocholic acid) were performed before and 2 and 12 weeks after operative intervention. Control dogs (CON, n = 6) underwent distal 50% enterectomy. Experimental dogs (EXT DEN, n = 6), in addition to resection, underwent complete extrinsic denervation of the remaining jejunum. All dogs developed diarrhea, which resolved in all CON dogs but persisted in all EXT DEN dogs. Maximal weight loss was greater in the EXT DEN group. Glucose and oleate absorption was decreased 2 weeks after ileal resection in both the CON and EXT DEN dogs; glutamine absorption was decreased at 2 weeks in EXT DEN dogs only. Taurocholate and water absorption remained unchanged in both groups. Absorption of all solutes returned to baseline at 12 weeks in both groups. Despite greater weight loss and persistent diarrhea in EXT DEN dogs, at 12 weeks there were no differences in net absorptive fluxes between the EXT DEN and the CON group after extrinsic denervation. The extrinsic denervation necessitated by small bowel transplantation does not appear to blunt the net jejunal adaptive response to total ileal resection, but may temporarily alter glutamine absorption.

The effects of surgery on gastrointestinal motor activity

Gastrointestinal surgical procedures have the potential to disrupt motor activity in various organs of the gastrointestinal tract or, indeed, throughout the entire alimentary canal. Several of these motor effects have important clinical consequences and have also served to advance our understanding of the regulation of gastrointestinal motor activity. This review will focus, in particular, on the effects of surgery on the small intestine, and will attempt to emphasize the implications of these studies for our understanding of small intestinal motility, in general.

Edgar J. Poth Memorial Lecture. Surgical aspects of the short-bowel syndrome

BACKGROUND

Surgeons are frequently confronted with patients with the short-bowel syndrome. Important surgical issues are maintaining intestinal continuity, treating complications, and performing procedures to improve intestinal function.

METHODS

A comprehensive review of the English language literature and the author's own experience were employed to make recommendations about surgical management of the short-bowel syndrome.

CONCLUSION

At the time of initial resection, ostomy formation is often prudent. The decision to restore continuity at a later time should balance anticipated functional outcome against potential complications. Several surgical strategies can be employed at reoperation in these patients to minimize further loss of intestine. Prophylactic cholecystectomy should be considered because of the increased risk of cholelithiasis. Gastric hypersecretion rarely requires operative therapy. Surgical therapy for the short-bowel syndrome includes procedures to slow intestinal transit, optimize intestinal function, and increase intestinal surface area. The choice of operation is influenced by intestinal remnant length and caliber and its function. Only a small proportion of patients are candidates for nontransplant procedures, of which intestinal lengthening is most efficacious. Intestinal transplantation, either alone or combined with the liver, is emerging as the most promising therapy in short-bowel syndrome.

Effect of intestinal tapering and lengthening on intestinal structure and function

BACKGROUND

Intestinal lengthening (TL) is increasingly performed for the short bowel syndrome. Our aim was to evaluate the effect of TL on canine intestinal structure and function.

METHODS

Two groups of 5 dogs had 75% distal intestinal resection. Twelve weeks later, serosal electrodes were placed in one group (RO) and tapering and lengthening of 10 to 15 cm distal intestine and electrode placement was performed in the other group (TL). Nutritional status and intestinal absorption, motility, and hormone release were assessed every 4 weeks for 12 weeks after the second procedure.

RESULTS

The animals with the lengthening had diminished body weight (75% +/- 2% versus 81% +/- 4%, P < 0.05) and albumin levels (2.4 +/- 0.2 g/dL versus 2.9 +/- 0.5 g/dL, P < 0.05) and impaired absorption (stool fat 18% +/- 6% versus 10% +/- 3%, P < 0.05) compared with those that had undergone resection alone. The intestinal adaptive response was blunted in the TL group (villus height 328 +/- 90 microns versus 410 +/- 36 microns, P < 0.05). Transit time was prolonged 4 and 8 weeks (19 +/- 6 min and 18 +/- 5 min, respectively, versus 11 +/- 3 min, P < 0.05) after TL. Myoelectrical recordings showed a drop in slow wave frequency and impaired migration of Phase III of the migrating motor complex within the tapered and lengthened segments (P < 0.05). Both fasting and postprandial serum gastrin levels were two times greater in the TL group (P < 0.05). Enteroglucagon levels were increased after resection alone; this increase was attenuated by more than 50% in the TL group (P < 0.05). The somatostatin response to feeding was substantially greater in the TL animals.

CONCLUSIONS

TL impairs nutritional status and intestinal absorption and adaptation following massive resection. The changes in absorption and transit may be related, in part, to motor disruption and hypergastrinemia. The impaired adaptation is possibly related to decreased enteroglucagon and increased somatostatin levels.