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Gastroenterology & Hepatology
Crohn’s disease (CD) is a systemic disease, primarily affecting the gastro-intestinal tract, of which the etiology has not been clarified. Genetic and environmental factors are indicated to contribute to CD development. CD may affect any part of the digestive tract, whereas disease behavior may change over time and progress to fibrostenotic and penetrating disease. It is estimated that approximately 40% of CD patients will develop naïve symptomatic strictures (e.g., intestinal obstruction), whereas it is not uncommon for the development of anastomotic strictures. Diagnosis <40 years of age, need for steroids at diagnosis, small bowel involvement, and smoking has been associated with stricturing CD. Symptoms of stricturing CD may include nausea, vomiting, abdominal cramping, and abdominal flatulence, leading to decreased quality of life.
- Crohn’s disease
- strictures
- stenoses
- anti-TNF
- endoscopic balloon dilatation
- surgery
1. Introduction
An expert consensus defined small bowel stricture on imaging (Computed Tomography Enterography, Magnetic Resonance Enterography, and ultrasound) as “a localized luminal narrowing and bowel wall thickening with pre-stricture dilation”. Pre-stricture (or prestenotic) dilation is defined as a greater-than 3 cm bowel lumen diameter before the stenotic segment. Endoscopically, a naïve stricture is defined as the “Inability to pass an adult endoscope through the narrowed area without prior endoscopic dilation and with a reasonable amount of pressure applied”. On the other hand, successful treatment of a small bowel stricture is characterized by relief of clinical symptoms and improvement of endoscopic/radiologic features [2].CD-induced intestinal strictures may be differentiated into inflammatory, fibromatous, and mixed types. Patients with strictures with a predominately fibrotic component were not shown to benefit from medical management, which is only effective in patients with inflammatory intestinal strictures. In this case, endoscopic or surgical approaches may provide an efficient alternative therapeutic solution [3]. However, differentiating fibrotic from inflammatory strictures is challenging, as most imaging techniques, such as CT or MR enterography, show limitations regarding the discrimination of fibrotic and inflammatory strictures. Nevertheless, the combination of novel imaging techniques, such as contrast-enhanced ultrasound and ultrasound elasticity imaging, appear to be promising diagnostic tools [4].
On the other hand, inflammatory markers, such as CRP and fecal calprotectin, may reflect CD activity, contributing to distinguishing between fibrotic and inflammatory strictures without being strictly specific [5]. Thus, clinicians should take into account the clinical course of CD, inflammatory biomarkers, and imaging techniques in order to diagnose a fibrotic or inflammatory stenosis.
2. Endoscopic Management
In patients with significant stenoses, where medical treatment fails to resolve symptoms, endoscopy and surgery offer effective alternative treatment solutions.
2.1. Endoscopic Balloon Dilation
Endoscopic balloon dilation of a strictured segment with a through-the-scope (TTS) balloon is demonstrated to be a minimally invasive, safe, and effective method [18,19] with a small risk of major complications [20,21], enabling the deferral of surgery [22] and thus allowing bowel length conservation.
The technique of endoscopic balloon dilation is rather simple; the stenosis is approached with the endoscope in a retrograde or anterograde manner, the TTS balloon is gently placed inside the stricture and then hydrostatically dilated with water or contrast inside the balloon [23].
Practically, endoscopic balloon dilation can be performed in any part of the gastrointestinal tract, in endoscopically reachable anastomotic or naïve non-malignant strictures [24,25,26]. However, colonic strictures are associated with malignancy in a small but significant percentage of patients [27]. In contrast, the role of endoscopic biopsies in the guidance of therapeutic decisions in patients with colonic strictures is debatable, as tissue samples negative for malignancy were not shown to rule out the presence of dysplasia in 0,8% of CD and 5% of UC patients [27].
Candidates for a successful EBD are patients with partial or resolving symptoms of obstruction, short (≤5 cm), non-angulated, uncomplicated (without extensive ulcerations, fistulization, abscess, perforation) naïve, distal to the duodenum strictures [6,23,28,29].
Stricture location, length, and anatomy determine the choice of balloon size, dilation, duration, and dilation approach, namely, graded (a gradual increase of balloon size) or non-graded dilation [30]. Usually, balloon size ranges between 12–20 mm, with smaller sizes used in the small bowel and larger sizes in the colon. However, the use of larger size balloons is associated with perforation and bleeding without any additional benefit [31]. Furthermore, the more distal the stenosis, the larger the diameter of the lumen must be to allow for proper stool passage, which is indeed less of a problem when dilating proximal (small bowel stenosis).
The likelihood of repeated dilations and the requirement for surgery following dilation in a considerable number of patients are both disadvantages of EBD [32]. Moreover, EBD entails a small but significant risk of complications, namely bowel perforation, severe bleeding, sepsis, abscess, fistula formations [33]. In particular, major EBD complications (e.g., perforation, bleeding, or dilation-related surgery) were estimated to occur in 5.3–6.4% of patients undergoing EBD [20,21].
A consensus regarding the definition of endoscopic balloon dilation efficacy is lacking. Various studies have estimated efficacy by presenting short-term, as well as long-term results (Table 2).
A short-term result could be defined as the immediate technical success of the procedure, which the passage of the endoscope can determine through the stricture after endoscopic balloon dilation, marked by symptom resolution. In contrast, long-term efficacy could be defined by the time until a repeated EBD or surgical intervention is required.
Regarding short-term results, the technical success rate of EBD is estimated at >90%, with clinical efficacy (symptom resolution) varying between 70–80% [20,21]. As it concerns for long-term results, almost 75% of patients with stricturing CD required redilation during a 2-year follow up [25]. Moreover, the cumulative surgery rate during a 5-year follow-up after EBD was 75% [21]. Stricture length (>4 cm) was the most significant factor of stricture recurrence [33,34].
Table 2. Studies about endoscopic techniques of stricturing Crohn’s disease.
| Study Design | Endoscopic Technique | Number of Patients | Successful Rates (Technical) | Complications | Study (Year of Study) |
|---|---|---|---|---|---|
| Meta-analysis | Endoscopic Balloon Dilation | 463 | 94.9% | 5.3% | Bettenworth D et al. [26] (2020) |
| Meta-analysis | Endoscopic Balloon Dilation | 1089 | 90.6% | 6.4% | Morar PS et al. [21] (2015) |
| Meta-analysis | Endoscopic Balloon Dilation | 1463 | 89.1% | 2.8% | Bettenworth D et al. [25] (2017) |
| Retrospective | Endoscopic Stricturotomy | 85 | 100% | 3.7% | Lan N et al. [35] (2017) |
| Retrospective | Endoscopic Stricturotomy | 21 | 100% | 8.8% | Lan N et al. [36] (2018) |
2.2. Endoscopic Stricturotomy
Endoscopic stricturotomy is an innovative technique where an endoscopic needle knife or endoscopic insulated-tip knife is used for the radial incision of a strictured segment.
Although the available data are scarce, the immediate technical success rate of endoscopic stricturotomy, defined as the successful passage of the endoscope through the strictured segment after stricturotomy, was demonstrated to be high [35] and more efficient than endoscopic balloon dilation [36].
Despite the low risk of perforation and low complication rate, endoscopic stricturotomy was shown to have a higher bleeding risk than endoscopic balloon dilation [35,36].
2.3. Other Endoscopic Procedures
Although intra-lesional injection with long-acting corticosteroids has emerged as a promising technique for managing stricturing CD, current evidence does not support this practice [28]. In addition, a few small case series have reported benefits with intra-lesional infliximab injections, however the efficacy of this therapeutic strategy requires validation with studies of a higher level of evidence [28].
3. Surgical Management
A significant number of CD patients will require surgery to manage fibrostenotic disease, namely resection of the stenotic segment or strictureplasty. A third surgical option, bypass, is mainly indicated for strictures of the gastroduodenal region.
3.1. Surgical Resection
Despite the ongoing development of new biologic agents, the risk of intestinal surgery remains high during the disease course. This risk is higher, in patients with a wrong initial diagnosis, delay of diagnosis, and perioperative complication, whereas a number of CD patients will require repeated intestinal resections. Despite the progress in therapeutic options, intestinal-resection associated loss of function bowel length put these patients at risk of short bowel syndrome [37].
Surgical resection is indicated in patients who are not suitable candidates for EBD or stricturotomy, namely when there are complications close to the stricture (fistula, abscess, phlegmon) when there are emergency conditions such as perforation or massive bleeding and when there is a high suspicion of malignancy (e.g., colonic strictures) [38,39].
In addition, early bowel resection could be an option in high-risk patients with isolated ileocecal stricturing CD, as this practice is demonstrated to offer better outcomes when compared to medical treatment regarding the subsequent development of fistula or intestinal obstruction [6].
A laparoscopic approach should be preferred, when possible, as it is associated with reduced morbidity, shorter hospital stay, and reduced iatrogenic complications such as adhesions and hernia formation, whilst it allows improved cosmesis [38]. Past surgery and emergency surgery and malnutrition and anemia, which ideally should be corrected before surgery, were associated with worse outcomes [39]. The main drawback of surgical resection is the reduction of small bowel length, which in case of repeated or extensive surgeries may result in short bowel syndrome. Therefore, the resection should involve the stenotic small bowel segment with margins of 2 cm or less, regardless of the histological activity of the disease in the margins, as it is not demonstrated to affect recurrence [40].
The main types of surgical anastomosis for structuring CD are end-to-end and side-to-side anastomosis. Although the level of evidence is mainly based on a meta-analysis of retrospective studies, with only a small number of randomized control trials, a side-to-side anastomosis was demonstrated to have fewer complications, especially anastomotic leak, and a smaller risk of postoperative recurrence [41,42,43,44,45]. Furthermore, the Kono-S anastomosis and extended mesenteric excision are two surgical methods that have shown promise in lowering postoperative recurrence rates [46,47]. Preoperative treatment with prednisolone >20 mg/day (or other equivalents) increases the risk of anastomotic leakage, surgical site infections and sepsis, whilst the data regarding the use of infliximab-associated postoperative complications are conflicting [39].
3.2. Strictureplasty
Strictureplasty is a bowel-length-conserving surgical method, as it allows the widening of the narrowed part of the intestinal stricture without removing an intestinal segment. Moreover, strictureplasty offers the advantage of multiple strictureplasties if necessary, and it can also be combined with surgery.
Practically every stricture in the jejunum and the ileum outside of endoscopic reach are amenable to strictureplasty [39]. However, strictureplasty is not indicated in patients with long strictures (>68 cm), acute inflammation, local complications (e.g., fistula, abscess, perforation), or suspicion of malignancy. Moreover, strictureplasty is not a therapeutic option in patients with gastric, ileocolonic, or colonic involvement [39].
The main types of strictureplasty are three depending on the length of the intestine:
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The Heineke–Mikulicz strictureplasty for strictures <10 cm;
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The Finney strictureplasty for strictures between 10–25 cm;
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Non-conventional strictureplasties such as the Michelassi strictureplasty for longer strictures up to 68 cm.
In all three types, strictureplasty involves a longitudinal incision along the anti-mesenteric border, and depending on the type, a specific suture method on the strictured area is applied. Despite the fact that it could be difficult to reliably measure a long strictured segment, strictureplasty is not indicated in patients with long strictures (>68 cm).
Strictureplasty complications include small bowel obstruction, sepsis, and other infections, bleeding, progression to cancer of the stenotic segment, mortality, and stricturing reoccurrence, which requires subsequent strictureplasty [48].
Furthermore, non-conventional strictureplasties should be considered in patients with extensive strictures after prior surgical resection in order to avoid complications, such short bowel syndrome [49]. It is worth mentioning that post-operative quality of life of patients after strictureplasty is comparable with resection [50].
4. Surgery of Duodenal Strictures
The surgical management of duodenal strictures in Crohn’s disease patients is challenging, as the duodenum is adjacent to the ampulla of Vater, the pancreas, and the mesenteric vasculature; bypass surgery with or without vagotomy, usually with either a gastrojejunostomy or a gastroduodenostomy repair, is one surgical option for controlling gastroduodenal Crohn’s disease [51].
Other options encompass strictureplasty of the duodenum; however, it is not indicated in strictures <10 cm or surgical resection, including pancreas-sparing duodenectomy and pancreaticoduodenectomy, which carry significant complications [52]. Nevertheless, each surgical approach, such as strictureplasty, bypass, and resection, has a distinct purpose, and these alternatives must be customized to the strictures’ characteristics (number, length, and location) and the patient’s comorbidities [53,54].
This entry is adapted from the peer-reviewed paper 10.3390/jcm11092366
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