**3. Complications associated with specific colonoscopic interventions**

#### **3.1. Colonoscopic tattooing**

were more common in women, and when the procedure lasted 20 minutes or longer. Colon‐ ic preparation was reported by patients as the most difficult part of the procedure in 77%. Most patients (94%) missed 2 or fewer days from normal activities for the preparation, pro‐

These minor adverse events have 3 aspects of effect; they are inconvenience to patients, have indirect cost by missing work, and can affect the willingness of patients to undergo any fur‐

Reducing looping of the endoscope and minimizing air insufflation may decrease some of these symptoms [53]. It has been also suggested using carbon dioxide, which is rap‐ idly absorbed and excreted through lungs, as an insufflating gas for colonoscopy to re‐ duce these symptoms [54,55]. Also water immersion technique instead of air insufflation has been proposed to reduce these minor events especially in cases of min‐

The most serious miscellaneous complications have reported within 30 days of colonoscopy are cerebrovascular accident (CVA), transient ischemic attack (TIA), and pulmonary embo‐ lisms which most likely related to temporary cessation of anticoagulation agents and anti‐

Stroke or TIA occurred within 30 days of colonoscopy in 3.3 cases per 10,000 colonoscopies in study of 21,375 patients [3]. In a study of 1,528 patients, there was one case of TIA, and one case of pulmonary embolism within 30 days of colonoscopy (6.5 cases of each per 10,000 colonoscopies) [8]. A third study of 23,508 patients, there were two cases of TIA and reversi‐ ble ischemic neurologic deficit lasting 24 hours and 72 hours, occurring in recovery period following the procedure (0.8 per 10,000 colonoscopies) [13]. However, these rates are compa‐

Splenic hematoma and rupture, intramural hematoma, subcutaneous emphysema in the ab‐ sence of frank colonic perforation, tearing of mesenteric vessels with intra-abdominal bleeding, thrombosis in carotid-subclavian artery bypass graft, thrombophlebitis in the intravenous site, intestinal obstruction, and ischemic and chemical colitis secondary to glutaraldehyde or air in‐

Although it is not a true complication of colonoscopy, missing colorectal polyps and cancer is of importance because it affects patient's safety, malpractice, and determining the surveil‐ lance interval for repeat colonoscopy. In a study of 235 patients, the miss rate for advanced adenomas which defined as polyps ≥10 mm with or without a villous component or highgrade dysplasia was 2.5% and 3.3% for patients who had complete colonoscopy and satisfac‐ tory colon preparation on second and third repeat colonoscopy, respectively [59]. There was

rable with the expected annual adjusted rate of stroke in general population [3].

sufflation have been reported following colonoscopy in literature [3,14,15,23,31,57,58].

cedure itself, or recovery [52].

ther colonoscopy in future if need it.

226 Colonoscopy and Colorectal Cancer Screening - Future Directions

imal sedation [56] (Leung 2010).

**2.11. Polyp and cancer miss rates**

no cancer missed [59].

platelet medications peri-procedure period [3,6-8,13].

**2.10. Miscellaneous**

Colonic tattooing is an injection of permanent dye into the submucosal layer of colon wall that adjacent to the lesion for easier future localization either for surgical resection or colo‐ noscopic follow-up. Although three studies with a total of 264 patients who underwent colo‐ noscopic tattooing reported no fever, abdominal pain, or any major complications [64-66], a systematic review of 447 patients with colonoscopic tattooing described 5 cases of complica‐ tions with only one was an overt clinical complication (22.3 per 10,000 tattooing) [67].

It has been reported cases of intramural hematoma, colonic abscess, rectus muscle ab‐ scess following colonoscopic tattooing, bowel obstruction, retroperitoneal colonic perfo‐ ration due to localized necrosis, adhesion ileus, and spread of the dye following colonoscopic tattooing [68-75].

#### **3.2. Colonic balloon dilation**

Colonic dilation has been used as a non-surgical treatment for benign strictures that associ‐ ated with Crohn's disease and those at surgical anastomoses [76].

In a systematic review in 2007 of 13 studies with 347 patients with Crohn's disease with colonic strictures who underwent 695 sessions of colonic dilation, there were 14 cases of major complications (201.4 cases per 10,000 colonic dilations); 13 cases being bowel perforation (92.8%) [77].

Two prospective studies with a total of 42 patients with benign colorectal anastomotic steno‐ sis, not associated with Crohn's disease, who underwent 81 sessions of colonic dilation re‐ ported no procedure-related complications [78,79].

**3.5. Percutaneous endoscopic colostomy**

tients who undergo PEC [92-94].

**3.6. Colonic hemostasis**

and injection needles [95].

complications of ACP [95,97,98].

failing to extend from their sheaths [95].

**3.7. Foreign body removal**

genic bowel or severe slow-transit constipation [76,92-94].

Percutaneous endoscopic colostomy (PEC) is considered a minimally invasive endoscopic procedure that has been used as an alternative modality to surgery in poor surgical candi‐ dates who have recurrent sigmoid volvulus, recurrent colonic pseudo-obstruction, neuro‐

Complications of Colonoscopy http://dx.doi.org/10.5772/53202 229

The complications of PEC that has been reported are fecal peritonitis (8.5%), fecal leakage, recurrent infections (77%), buried internal bolster, abdominal wall bleeding and pain [92-94]. All-cause mortality has been reported as high as 26% reflecting the often frail pa‐

Colonic hemostasis devices are used to treat GI bleeding including diverticular bleeding, postpolypectomy bleeding, angiodysplasia, and radiation-induced angioectasias. Colonic hemostasis devices include contact thermal devices (eg, heater probe [HP], multipolar electrocautery [MPEC] probes, and hemostatic graspers), noncontact thermal devices (eg, argon plasma coagulator [APC]), mechanical devices (eg, band ligators, clips, and loops)

Initial worsening of bleeding may occur when applying any of these devices which can be successfully treated by an additional application of the same or different device [15]. Colonic perforation especially right colon has been reported as high as 2.5% with ther‐ mal devices [15,95,96]. Distention of the GI tract with argon gas, submucosal emphyse‐ ma, pneumomediastinum, pneumoperitoneum, and gas explosion has been reported as

There are multiple reports of premature deployment of the clip, and the failure to separate the clip from the catheter after deployment [95]. Colonic perforation, initial worsening bleeding, clip retention, immediate or delayed bleeding secondary to slippage of loop when

The complications of injection needles are usually related to injected substances such as car‐ diac arrhythmias and hypertension due to epinephrine, however, there are reports of nee‐ dles separating from the catheter in the patient and requiring retrieval, and of needles

Colorectal foreign bodies may result from the insertion in the rectum for sexual pleasure, non-sexual purposes such as body packing of illicit drugs for transportation purposes, acci‐ dentally, by swallowing solid objects such as bones and toothpicks, or migration into the co‐ lon from the adjacent organs such as intrauterine contraceptive devices and inguinal hernia mesh [15,100-103]. Numerous kinds of objects have been described in the literature includ‐ ing fruits, vegetables, cans, bottles, bull horn, batteries, light bulbs, cosmetic containers, and children or sex toys [100,104]. The presenting symptoms of colorectal foreign bodies are pel‐

using detachable loop ligating devices have been described [95,99].

#### **3.3. Colonic stent placement**

Self-expandable metal stents (SEMS) have been used in the management of colorectal obstruc‐ tion as a bridge to surgery or as a palliative treatment especially malignant obstruction. In a pooled analysis of 54 studies with 1,198 patients who underwent colonic stent placement, the major complications related to stent placement included stent migration (11.81%), reobstruc‐ tion (7.34%), perforation (3.76%), and mortality (0.58%) [80]. The risk factors for stent migration which may occur proximally or distally were using covered stent, laser treatment, dilation prior stent insertion, and the use of chemotherapy and radiotherapy. The causes for reobstruction were tumor ingrowth (73.2%), fecal impaction, mucosal prolapse, stent migration, tumor over‐ growth, and peritoneal seeding. The reobstruction was significantly higher in uncovered stents. The perforation was related to stent wires, balloon dilation, guide wires, or related to laser re‐ canalization prior stent placement. The death was related to colonic perforation and its conse‐ quences in majority of cases [80].

In another systematic review of 1,785 patients with 1,845 stent placements, colonic reob‐ struction in 12%, migration of the stent occurred in 11%, perforation in 4.5%. Other reported complications of stent placement included GI bleeding, anal pain, abdominal pain, and ten‐ esmus which were relatively rare and generally well tolerated by patients [81]. It is not rec‐ ommended to perform dilation around the time of stent placement due to increased perforation risk [76,80].

Despite of the early termination of 3 randomized controlled trials comparing SEMS to surgery because of high rate of complications in SEMS groups, a recent systematic re‐ view in 2012 with 234 patients including these 3 trials showed that the clinical perfo‐ ration rate was 6 9% and the silent perforation rate 14%. There was no difference between SEMS arm and emergent surgery in primary anastomosis, permanent stoma, in-hospital mortality, anastomotic leak, 30-day reoperation and surgical-site infection rates [82-85].

#### **3.4. Colonic decompression tube placements**

Transanal endoscopic decompression tube placement has been used in acute colorectal ob‐ struction or pseudo-obstruction before surgery or stenting.

In 5 series consisting of 153 patients with acute colonic obstruction treated with transanal decompression tube placement, two cases of bowel perforation occurred (1.3%) [86-90].

In a series of 50 patients with acute colonic pseudo-obstruction who underwent 54 decom‐ pression tube placements, one case of bowel perforation occurred (2%), and overall in-hospi‐ tal mortality was 30% reflecting severe underlying comorbidities [91].

#### **3.5. Percutaneous endoscopic colostomy**

Percutaneous endoscopic colostomy (PEC) is considered a minimally invasive endoscopic procedure that has been used as an alternative modality to surgery in poor surgical candi‐ dates who have recurrent sigmoid volvulus, recurrent colonic pseudo-obstruction, neuro‐ genic bowel or severe slow-transit constipation [76,92-94].

The complications of PEC that has been reported are fecal peritonitis (8.5%), fecal leakage, recurrent infections (77%), buried internal bolster, abdominal wall bleeding and pain [92-94]. All-cause mortality has been reported as high as 26% reflecting the often frail pa‐ tients who undergo PEC [92-94].

#### **3.6. Colonic hemostasis**

Two prospective studies with a total of 42 patients with benign colorectal anastomotic steno‐ sis, not associated with Crohn's disease, who underwent 81 sessions of colonic dilation re‐

Self-expandable metal stents (SEMS) have been used in the management of colorectal obstruc‐ tion as a bridge to surgery or as a palliative treatment especially malignant obstruction. In a pooled analysis of 54 studies with 1,198 patients who underwent colonic stent placement, the major complications related to stent placement included stent migration (11.81%), reobstruc‐ tion (7.34%), perforation (3.76%), and mortality (0.58%) [80]. The risk factors for stent migration which may occur proximally or distally were using covered stent, laser treatment, dilation prior stent insertion, and the use of chemotherapy and radiotherapy. The causes for reobstruction were tumor ingrowth (73.2%), fecal impaction, mucosal prolapse, stent migration, tumor over‐ growth, and peritoneal seeding. The reobstruction was significantly higher in uncovered stents. The perforation was related to stent wires, balloon dilation, guide wires, or related to laser re‐ canalization prior stent placement. The death was related to colonic perforation and its conse‐

In another systematic review of 1,785 patients with 1,845 stent placements, colonic reob‐ struction in 12%, migration of the stent occurred in 11%, perforation in 4.5%. Other reported complications of stent placement included GI bleeding, anal pain, abdominal pain, and ten‐ esmus which were relatively rare and generally well tolerated by patients [81]. It is not rec‐ ommended to perform dilation around the time of stent placement due to increased

Despite of the early termination of 3 randomized controlled trials comparing SEMS to surgery because of high rate of complications in SEMS groups, a recent systematic re‐ view in 2012 with 234 patients including these 3 trials showed that the clinical perfo‐ ration rate was 6 9% and the silent perforation rate 14%. There was no difference between SEMS arm and emergent surgery in primary anastomosis, permanent stoma, in-hospital mortality, anastomotic leak, 30-day reoperation and surgical-site infection

Transanal endoscopic decompression tube placement has been used in acute colorectal ob‐

In 5 series consisting of 153 patients with acute colonic obstruction treated with transanal decompression tube placement, two cases of bowel perforation occurred (1.3%) [86-90].

In a series of 50 patients with acute colonic pseudo-obstruction who underwent 54 decom‐ pression tube placements, one case of bowel perforation occurred (2%), and overall in-hospi‐

ported no procedure-related complications [78,79].

228 Colonoscopy and Colorectal Cancer Screening - Future Directions

**3.3. Colonic stent placement**

quences in majority of cases [80].

perforation risk [76,80].

**3.4. Colonic decompression tube placements**

struction or pseudo-obstruction before surgery or stenting.

tal mortality was 30% reflecting severe underlying comorbidities [91].

rates [82-85].

Colonic hemostasis devices are used to treat GI bleeding including diverticular bleeding, postpolypectomy bleeding, angiodysplasia, and radiation-induced angioectasias. Colonic hemostasis devices include contact thermal devices (eg, heater probe [HP], multipolar electrocautery [MPEC] probes, and hemostatic graspers), noncontact thermal devices (eg, argon plasma coagulator [APC]), mechanical devices (eg, band ligators, clips, and loops) and injection needles [95].

Initial worsening of bleeding may occur when applying any of these devices which can be successfully treated by an additional application of the same or different device [15]. Colonic perforation especially right colon has been reported as high as 2.5% with ther‐ mal devices [15,95,96]. Distention of the GI tract with argon gas, submucosal emphyse‐ ma, pneumomediastinum, pneumoperitoneum, and gas explosion has been reported as complications of ACP [95,97,98].

There are multiple reports of premature deployment of the clip, and the failure to separate the clip from the catheter after deployment [95]. Colonic perforation, initial worsening bleeding, clip retention, immediate or delayed bleeding secondary to slippage of loop when using detachable loop ligating devices have been described [95,99].

The complications of injection needles are usually related to injected substances such as car‐ diac arrhythmias and hypertension due to epinephrine, however, there are reports of nee‐ dles separating from the catheter in the patient and requiring retrieval, and of needles failing to extend from their sheaths [95].

#### **3.7. Foreign body removal**

Colorectal foreign bodies may result from the insertion in the rectum for sexual pleasure, non-sexual purposes such as body packing of illicit drugs for transportation purposes, acci‐ dentally, by swallowing solid objects such as bones and toothpicks, or migration into the co‐ lon from the adjacent organs such as intrauterine contraceptive devices and inguinal hernia mesh [15,100-103]. Numerous kinds of objects have been described in the literature includ‐ ing fruits, vegetables, cans, bottles, bull horn, batteries, light bulbs, cosmetic containers, and children or sex toys [100,104]. The presenting symptoms of colorectal foreign bodies are pel‐ vic pain, abdominal pain, the peritoneal signs if perforation occurs, rectal bleeding, rectal mucous drainage, fecal incontinence, bowel obstruction, or drug overdose if bag ruptures during removal attempts in body pocking of illicit drugs [15,100,101,104].

**Author details**

**References**

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These symptoms and the management varies considerably based on the type of inserted ob‐ jects (sharp versus blunt), traumatic or not, and illicit drug involved or not [15,101]. Manage‐ ment of colorectal foreign bodies can be challenging and a systematic approach should be employed including abdominal plain film and CT scan to evaluate for free intra-abdominal air, shape and size of object, and its location and relations to the pelvis [15,100,101]. The ma‐ jority of cases can be successfully managed conservatively, but occasionally such as large ob‐ jects or tightly wedged in the pelvis surgical intervention is warranted [15,100]. It not recommended removing drug-containing bags endoscopically because of potential rupture of bags that can lead to systemic absorption of the drug which may cause death from rapid drug overdose [15,105].

#### **3.8. Advanced techniques for colonoscopic tissue removal**

These advanced techniques include endoscopic mucosal resection (EMR) and endoscopic sub‐ mucosal dissection (ESD) that have been used to remove benign and early malignant lesions that confined to superficial layers (mucosa and submucosa) [15,106]. Perforation and bleeding are the most common complications for EMR and ESD which are more frequent than with standard polypectomy [15]. The size of lesion, location, histology, the type of device used, and operator experience are the factors that affects complication rates [15,107-109].

Intraprocedural bleeding rate has been reported over 10% in several large studies with de‐ layed bleeding to up to 14% [15,101,102]. Bleeding usually is managed endoscopically, al‐ though it may require blood transfusion [15,110].

Perforation may occur in 0-5% and 5-10% in EMR and ESD respectively which is usually rec‐ ognized during the procedure and managed endoscopically, although delayed perforation has been reported in 0.4% [15,107-111].
