Outcome of colonoscopic decompression in acute colonic pseudo-obstruction: A systematic review and meta-analysis

Abstract

BACKGROUND

Acute colonic pseudo-obstruction (ACPO) is defined as colonic obstruction without a mechanical or extrinsic inflammatory factor. Colonic decompression is advised for patients with ACPO after the failure of conservative and medical management.

AIM

To systematically review and analyze the efficacy and safety of colonoscopic decompression in ACPO.

METHODS

A search was conducted in MEDLINE, EMBASE, and Scopus from inception to August 2024. Studies reporting the clinical success, perforation, recurrence, and need for surgery after colonoscopic decompression in ACPO were included. A random-effects inverse-variance model was used to calculate the pooled proportion.

RESULTS

Sixteen studies were included in the final analysis. The pooled rates of success after the first session of colonoscopic decompression and overall success were 78.8% (95%CI: 72.0-85.6) and 91.5% (95%CI: 87.0-96.0), respectively. The first session of colonoscopic decompression had a significantly higher success than the first dose of neostigmine with OR 3.85 (95%CI: 2.00-7.42). The pooled incidence of perforation was 0.9% (95%CI: 0.0-2.0), while recurrence was observed in 17.1% (95%CI: 12.9-21.3) of the patients after clinical success. The pooled rates of surgery in all cases undergoing colonoscopic decompression and those who had a successful procedure were 10.5% (95%CI: 5.0-15.9) and 3.7% (95%CI: 0.3-7.1), respectively. Subgroup analysis, excluding the low-quality studies, did not significantly change the event rates.

CONCLUSION

Colonoscopic decompression for ACPO is associated with a clinical success rate of > 90% with a perforation rate of < 1%, demonstrating high efficacy and safety.

Key Words: Acute colonic pseudo-obstruction; Ogilvie's syndrome; Colonoscopy; Colonoscopic decompression; Neostigmine

Core Tip: Colonoscopic decompression for acute colonic pseudo-obstruction (ACPO) was associated with a pooled success rate of 78.8% after the first session and an overall success rate of 91.5%. The first session of colonoscopic decompression had a significantly higher success than the first dose of neostigmine with OR 3.85. The pooled incidence of perforation remained less than 1%, while one-sixth of the patients had a recurrence after clinical success. Surgery was required in 3.7% of those who had a successful procedure and 10.5% of all cases receiving colonoscopic decompression. In patients undergoing colonoscopic decompression, tube placement should be attempted with the position of the tube at least until the transverse colon to improve clinical success and reduce recurrence. However, the predictors of failure of colonoscopic decompression in ACPO need to be studied further.

INTRODUCTION

Colonic obstruction accounts for approximately 25% of all cases of intestinal obstructions[1]. Intestinal obstruction can be either functional or mechanical. Acute colonic pseudo-obstruction (ACPO) or Ogilvie's syndrome is defined as colonic obstruction without a mechanical or any extrinsic inflammatory factor[2-4]. Trauma, presence of sepsis, history of recent surgery, old age, neurologic causes, and use of opiates and chemotherapeutic agents are implicated in the development of ACPO[5]. The management options for ACPO include conservative treatment that consists of bowel rest, nasogastric decompression, electrolytes corrections, and halting of implicating factor. In patients not responding to this treatment, the available treatment options are the use of neostigmine and colonoscopic decompression[2].

American Society for Gastrointestinal Endoscopy (ASGE) recommends colonoscopic decompression with decompression tube placement for patients with ACPO who are not candidates for conservative treatment or nonresponsive to it (for 72 hours) and have no contraindication to colonoscopy[2]. Colonoscopic decompression is a minimally invasive procedure and reduces the need for surgery in patients of ACPO. However, it may be associated with perforation. There is no published meta-analysis on the outcome of colonoscopic decompression in patients of ACPO. The aim of this analysis is to systemically appraise the published literature on the efficacy and safety of colonoscopic decompression in ACPO.

MATERIALS AND METHODS

The current meta-analysis was conducted as per the updated Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines[6].

Database search

The electronic databases of MEDLINE, Embase, and Scopus were searched from inception until August 31, 2024 using the following keywords: (Pseudo-obstruction AND (Colonic OR Intestinal) OR Ogilvie) AND Colonoscop). Before including the studies, two independent reviewers evaluated the titles and abstracts of the retrieved papers to determine their eligibility. Furthermore, the listed papers' bibliographies were examined for relevant studies. Any dispute was settled by a third reviewer.

Study inclusion

Both prospective and retrospective studies fulfilling the following criteria were included: (1) Study population: Patients with ACPO; (2) Intervention: Colonoscopic decompression; and (3) Outcomes: Efficacy and safety of colonoscopic decompression in ACPO. Editorials, correspondences, case reports, case series (< 10 patients), conference abstracts, and review articles were excluded. Studies with insufficient or irrelevant clinical data were also excluded.

Data extraction and quality assessment

Two reviewers independently extracted the data, while a third reviewer arbitrated any conflicts. Each study's title, first author, year of publication, country, number of patients, age and sex distribution, etiology, cecal diameter, prior intervention, and outcomes. Two independent reviewers used a modified Newcastle-Ottawa scale for cohort studies for quality assessment[7]. In the event of a disagreement, a third reviewer was contacted.

Outcomes assessed

The primary outcomes of the study were initial success (after the first session), overall success (after multiple sessions), perforation, recurrence after successful decompression, and the need for surgery. Due to heterogeneity in the definition of clinical success (clinical ± radiological), we defined clinical success based on clinical criteria only (reduction in abdominal distension with the passage of flatus and stool).

Data analysis

The pooled proportions were calculated using a random-effects inverse-variance model. I² and the P value for heterogeneity were used to evaluate the studies' degree of heterogeneity. I² values of 25%, 50%, and 75% were considered the cut-offs for low, moderate, and considerable heterogeneity, respectively[8]. A P value of less than 0.10 was considered statistically significant. Funnel plots were visually inspected to assess publication bias. Egger’s test was used to assess the small-study effect. The sensitivity analysis utilized a leave-one-out meta-analysis and sub-group analysis after the exclusion of low-quality studies. Meta-regression was utilized to evaluate the source of heterogeneity by the analysis of linear association between study-level variables and effect magnitude. STATA software (version 17, StataCorp., College Station, TX) was used for statistical analysis.

RESULTS

Baseline characteristics of the studies

A total of 1284 records were identified with the search strategy, of which 16 studies were included in the final analysis[9-24]. Figure 1 shows the PRISMA flowchart for the study selection and inclusion process. Tables 1 and 2 show the baseline characteristics and outcomes of the individual studies included in the present analysis. All studies were retrospective, except for the study by Zhao et al[20], which was prospective. The majority of the studies were from the United States. The sample size of the studies varied from 16 to 83, with the median age varying from 56 to 72 years. Males constituted the majority of the patients, with the proportion of post-surgical cases varying from 27% to 81.8%. The average cecal diameter varied from 9 to 13 cm. Supplementary Table 1 shows the quality analysis for individual studies. The majority of the studies were of medium quality, while six studies were of low quality[17-20,23,24].

Figure 1  Preferred Reporting Items for Systematic Reviews and Meta-Analyses flowchart for study identification, selection, and inclusion process.

Table 1 Baseline characteristics of the studies included in the meta-analysis, n (%).

Ref.	Study design, country	No. of patients	Age	Male sex	Etiology	Cecal diameter, in cm	Prior neostigmine	Tube placement
Nivatvongs et al[9]	Retrospective, United States	22	56 (30-82)	15 (68.2)	Post-surgical: 18 (81.8); Critically ill: 4 (18.2)	-	-	0
Strodel et al[10]	Retrospective, United States	44	59 (25-89)	31 (70.4)	Post-surgical: 12 (27); Critically ill: 29 (66)	12.8 (9.5-17)	-	0
Bode et al[11]	Retrospective, United States	22	64.3 (21-92)	15 (68.2)	Post-surgical: 13 (59.1); Critically ill: 9 (40.9)	12.9 (10-17)	-	0
Fausel and Goff[12]	Retrospective, United States	19	46-80	17 (89.4)	Post-surgical: 8 (42.1); Critically ill: 11 (57.9)	13 (12-15)	-	-
Lavignolle et al[13]	Retrospective, France	29	-	-	-	-	-	15 (51.7)
Harig et al[14]	Retrospective, United States	20	60-78	12 (60)	Post-surgical: 8 (40); Critically ill: 12 (60)	-	-	10 (52.6)
Jetmore et al[15]	Retrospective, United States	48	67 (36-90)	33 (68.7)	Post-surgical: 27 (56); Critically ill: 21 (44)	12.4	-	42 (87)
Geller et al[16]	Retrospective, United States	50	68 ± 13	33 (66)	Post-surgical: 33 (66); Critically ill: 17 (34)	13 (9-20)	-	42 (84)
Pham et al[17]	Retrospective, United States	24	65 (34-85)	20 (83)	Post-surgical: 9 (38); Critically ill: 15 (62)	12.6 ± 3.1	-	8 (75)
Tsirline et al[18]	Retrospective, United States	52	-	-	-	-	-	-
Peker et al[19]	Retrospective, Turkey	54	59.4 ± 15.3	-	-	10.8 ± 1.2	16 (30.2)	-
Zhao et al[20]	Prospective, China	59	-	-	-	-	59 (100)	-
Mankaney et al[21]	Retrospective, United States	83	66.8 ± 16.2	60 (72.3)	Post-surgical: 27 (32.5); Critically ill: 13 (54.2)	-	25 (30)	-
Liu et al[22]	Retrospective, United States	24	72.2 (51-93)	19 (79.2)	Post-surgical: 11 (45.8); Critically ill: 13 (54.2)	12.5	-	14 (58.3)
Joechle et al[23]	Retrospective, Germany	25	64 (34-86)	19 (76)	Critically ill: 25 (100)	9 (6-13)	-	19 (76)
Williamson et al[24]	Retrospective, United States	16	68 (62-84)	12 (73)	-	-	-	-

Table 2 Outcome of individual studies included in the analysis, n (%).

Ref.	No. of patients	Initial success	Overall success	Perforation	Recurrence after decompression	Need for surgery overall after successful decompression
Nivatvongs et al[9]	22	19 (86.4)	19 (86.4)	0	4/19 (21.0)	3/22 (13.6) | 2/19 (10.5)
Strodel et al[10]	44	32 (72.7)	34 (77.3)	1 (2.3)	5/34 (14.7)	7/44 (15.9) | 1/34 (2.9)
Bode et al[11]	22	20 (91)	20 (91)	1 (4.5)	4/20 (20)	3/22 (13.6) | 2/20 (10)
Fausel and Goff [12]	19	-	17 (89.5)	0	3/17 (17.6)	3/19 (15.8) | 2/17 (11.8)
Lavignolle et al[13]	29	-	29 (100)	0	7/29 (24.1)	-
Harig et al[14]	20	18 (90)	20 (100)	0	4/20 (20)	-
Jetmore et al[15]	45	29 (64.4)	38 (84.4)	1 (2.2)	6/38 (15.8)	5/45 (11.1)
Geller et al[16]	50	39 (78)	44 (88)	1 (2)	8/44 (18.2)	1/50 (2)
Pham et al[17]	24	22 (91)	23 (95.8)	0	-	-
Tsirline et al[18]	52	39 (75)	44 (85)	1 (1.9)	-	-
Peker et al[19]	54	44 (81.5)	-	-	-	-
Zhao et al[20]	59	27 (45)	-	-	-	-
Mankaney et al[21]	83	73 (87.9)	-	0	11 (15.1)	-
Liu 2021[22]	24	22 (91.6)	23 (95.8)	1 (4.2)	-	1/24 (4.2) | 1/23 (4.3)
Joechle et al[23]	25	17 (68)	-	6 (24)	-	8/25 (32) | 0/17
Williamson et al[24]	16	11 (68.7)	-	0	1/11 (9.1)	1/16 (6.2) | 0/11

Initial and overall success

Data on success after the first session of colonoscopic decompression for ACPO was available from 14 studies (n = 540). The pooled initial success rate was 78.8% (95%CI: 72.0-85.6; I² = 77.0%) with significant heterogeneity (Figure 2A). Leave-one-out analysis showed that the removal of the study by Zhao et al[20] increased the pooled initial success rate to 82.0% (95%CI: 77.0-87.0; I² = 52.7%) with moderate heterogeneity. Four studies (n = 349) compared the success after the first session of colonoscopic decompression and the first dose of neostigmine. Colonoscopic decompression had a significantly higher success with OR 3.85 (95%CI: 2.00-7.42; I² = 41.0%) (Figure 2B). Data on the overall success after one or more sessions of colonoscopic decompression for ACPO was available from 11 studies (n = 351). The pooled overall success rate was 91.5% (95%CI: 87.0-96.0; I² = 63.4%) with moderate heterogeneity (Figure 3A).

Figure 2 Forest plots. A: Pooled event rate for success after first session of colonoscopic decompression in acute colonic pseudo-obstruction; B: Comparison of success between first session of colonoscopic decompression and first dose of neostigmine.

Figure 3 Forest plots. A: Overall success after one or more sessions of colonoscopic decompression in acute colonic pseudo-obstruction; B: Recurrence after successful colonoscopic decompression in acute colonic pseudo-obstruction.

Perforation

Data on the incidence of perforation after colonoscopic decompression for ACPO was available from 14 studies (n = 475). The pooled incidence of perforation was 0.9% (95%CI: 0.0-2.0; I² = 0.0%) (Supplementary Figure 1). Leave-one-out analysis showed that the removal of the study by Mankaney et al[21] increased the perforation rate to 1.6% (95%CI: 0.1-3.1; I² = 0.0%) without heterogeneity.

Recurrence after successful decompression

Data on the recurrence of pseudo-obstruction after successful colonoscopic decompression for ACPO was available from 10 studies (n = 305). The pooled incidence of recurrence was 17.1% (95%CI: 12.9-21.3; I² = 0.0%) (Figure 3B).

Need for surgery

The need for surgery after colonoscopic decompression for ACPO was reported in 9 studies (n = 267). The pooled rate for surgery was 10.5% (95%CI: 5.0-15.9; I² = 59.9%) (Supplementary Figure 2A). Leave-one-out analysis showed that the removal of the study by Joechle et al[23] reduced the rate of surgery to 8.3% (95%CI: 3.8-12.9; I² = 0.0%) without heterogeneity. The need for surgery after successful colonoscopic decompression for ACPO was reported in 7 studies (n = 141). The pooled rate for surgery after successful colonoscopic decompression was 3.7% (95%CI: 0.3-7.1; I² = 0.0%) (Supplementary Figure 2B).

Publication bias, small-study effect, sub-group analysis, and meta-regression analysis

There was evidence of publication bias for the outcome of initial success but not for other outcomes (Supplementary Figure 3). Egger’s test did not show any evidence of a small-study effect for any of the outcomes (Supplementary Table 2). A sub-group analysis after exclusion of the low-quality studies did not show any significant difference in the pooled event rates but reduced the heterogeneity in the pooled rates of initial success (Table 3). Meta-regression analysis using sample size, year of publication, proportion of non-surgical patients, and proportion of patients having tube placement did not have any significant contribution from any of the covariates towards heterogeneity.

Table 3 Summary of findings from the overall and sub-group analysis.

Outcomes	Overall	Exclusion of low-quality studies
Initial success	78.8% (95%CI: 72.0-85.6), I2 = 77.0%	83.4% (95%CI: 77.0-89.7), I2 = 57.8%
Overall success	91.5% (95%CI: 87.0-96.0), I2 = 63.4%	91.6% (95%CI: 86.4-96.8), I2 = 65.7%
Perforation	0.9% (95%CI: 0.0-2.0), I2 = 0.0%	0.7% (95%CI: 0.0-1.9), I2 = 0.0%
Recurrence	17.1% (95%CI: 12.9-21.3), I2 = 0.0%	17.6% (95%CI: 13.2-21.9), I2 = 0.0%
Need for surgery	10.5% (95%CI: 5.0-15.9), I2 = 59.9%	8.9% (95%CI: 3.7-14.0), I2 = 50.8%
Need for surgery after success	3.7% (95%CI: 0.3-7.1), I2 = 0.0%	5.2% (95%CI: 1.2-9.3), I2 = 0.0%

DISCUSSION

Colonoscopic decompression is primarily used for patients with ACPO who fail conservative and pharmacological management. The present meta-analysis showed that the success of colonoscopic decompression after the first session was 78.8%, while the pooled overall success rate was 91.5%. The first session of colonoscopic decompression had a significantly higher success than the first dose of neostigmine with OR 3.85 (2.00-7.42). The pooled incidence of perforation was 0.9% (0.0-2.0), while recurrence was observed in 17.1% (12.9-21.3) of the patients. The pooled rate of surgery after colonoscopic decompression and those who had a successful procedure was 10.5% (5.0-15.9) and 3.7% (0.3-7.1), respectively.

The ASGE guidelines recommend neostigmine as the 1^st line therapy for the management of patients with ACPO after the failure of conservative treatment, and colonoscopy is recommended as an alternative therapy due to a lack of comparative studies regarding the same[2]. However, Tsirline et al[18] compared the outcome of neostigmine vs colonoscopic decompression as first-line therapy. They reported a higher success rate (defined as no further therapy requirement) with colonoscopy both after one intervention (75.0% vs 35.5%, P = 0.0002) and up to two interventions (84.6% vs 55.6%, P = 0.0031). Subsequently, Peker et al[19] compared colonoscopic decompression vs neostigmine as the first-line approach to ACPO and reported a higher success rate with colonoscopic decompression as the first approach (83.8% vs 48.4%). Data analysis from four studies showed that colonoscopic decompression had 3.85 times higher odds of achieving initial success than neostigmine. Despite this, the level of evidence remains low due to the absence of data from randomized studies. Hence, future studies are needed to analyze the utility of colonoscopic decompression as first-line therapy for ACPO.

Loftus et al[25] analyzed the factors associated with a sustained response to neostigmine for ACPO and reported that younger age was associated with a significantly lower response rate. Zhao et al[20] compared the outcome of patients with ACPO with no obvious thickening (edema) of the colonic wall (ACPO-NT) group and ACPO with acute thickening of the colonic gut wall (ACPO-T) group. The authors reported a higher response rate with non-surgical treatment in the ACPO-NT group, compared to the ACPO-T group (97.91% vs 64.4%, P < 0.01), although the response rate of colonoscopic decompression was comparable between both groups (75% vs 42.86%, P = 0.318). Thus, the younger age group and those with thickening of the colonic wall may represent the subset of patients who are at risk of failure to respond with neostigmine and may benefit from upfront colonoscopic decompression. However, further studies are required to validate these findings.

Randomized studies regarding the benefit of decompression tube placement after colonoscopic decompression are not available. Harig et al[14] compared the outcome of colonoscopic decompression with and without tube placement and reported a higher clinical success rate (100% vs 77.8%) with a lower incidence of reintervention (0% vs 44%) with tube placement. Geller et al[16] reported a higher clinical success rate of 80% (43 of 54) with colonoscopic decompression and tube placement, compared to 25% (2 of 8) in those without tube placement. The success rate of colonoscopic decompression was 90%, 83%, 63%, and 60% when the tubes were positioned in the cecum or ascending colon, transverse colon, hepatic flexure, and splenic flexure. Pham et al[17] reported that the placement of long colonic and rectal tubes appeared to give better decompression than the colonoscopy alone (P < 0.05). Thus, the tube should be placed in all patients undergoing colonoscopic decompression, with the position of the tube being as distally as possible, avoiding the placement in flexure, to achieve the best outcome.

Despite the benefit of colonoscopy, it is associated with the risk of adverse events as it is invasive. The reported incidence of perforation with colonoscopic decompression varied from 0 to 24%, with a pooled event rate of 0.9% (0.0-2.0). The incidence of perforation with colonoscopy and neostigmine were 1.9% and 4.4%, respectively, in the study by Tsirline et al[18] and Mankaney et al[21] reported no perforation in either of the groups. Thus, the overall incidence rate of perforation with colonoscopic decompression remains comparable to those treated with pharmacotherapy.

Joechle et al[23] reported that a colonic diameter ≥ 11 cm was the only independent factor for predicting non-response with colonoscopic decompression in ACPO. However, this inference was based on univariate analysis and not multivariate analysis. Peker et al[19] showed that old age, male sex, and associated cardiac disease were associated with poor response to colonoscopic treatment on univariate analysis. Mankaney et al[21] performed a multivariate analysis, and colonoscopic decompression (OR 2.6), reducing dose or stopping opioids (OR 2.7), and initial colonic diameter (OR 0.8) were found to be independent predictors of resolution of ACPO. Tsirline et al[18] reported that the number of doses of neostigmine before colonoscopy did not affect the success rate. Similarly, Peker et al[19] reported no difference in the response rate in patients undergoing upfront colonoscopy vs those who underwent colonoscopy after failed neostigmine. Thus, these factors should be kept in mind while proceeding with colonoscopic decompression for ACPO.

The present meta-analysis is the first to summarize the current evidence on the efficacy and safety of colonoscopic decompression in ACPO. The findings of our study may assist healthcare providers and patients while deciding colonoscopic decompression for ACPO and aid international organizations in formulating guidelines for safety and establishing acceptable thresholds for adverse events during the procedure. However, despite the encouraging outcomes, these results should be interpreted cautiously as the meta-analysis has several limitations. First, most of the studies were retrospective, increasing the risk of selection bias. Second, the definition of success varied between studies, contributing to heterogeneity. Third, all the included studies were of medium to low quality, reducing the level of evidence. Lastly, there was evidence of publication bias for the outcome of initial success. Publication bias in meta-analysis can lead to misleading conclusions by overestimating the true effect size of a phenomenon due to the tendency for studies with positive results to be published more readily than those with negative results, potentially distorting the overall interpretation of the research literature and impacting decision-making based on the meta-analysis findings. However, the exclusion of the low-quality studies removed the publication bias. Future prospective studies on the role of colonoscopic decompression in ACPO and randomized studies comparing colonoscopic decompression with neostigmine in ACPO are required to improve reliability and reduce the risk of selection bias.

CONCLUSION

To conclude, around three-fourths of the patients with ACPO respond after the first session of colonoscopic decompression, while > 90% respond after one or more sessions. In patients undergoing colonoscopic decompression, tubes should be placed with the position of the tube at least until the transverse colon to improve clinical success and reduce recurrence. The incidence of perforation remains less than 1%, which is reassuring. One-sixth of the patients will have recurrence after successful decompression. Surgical management is required in around 10% and 3.7% of patients undergoing colonoscopic decompression and successful colonoscopic decompression, respectively. Further studies are required to identify the predictors of failure of neostigmine and colonoscopic decompression to decide optimal management strategies.