Application of a novel small intestine decompression method in patients with intestinal obstruction: A retrospective cohort study

Abstract

BACKGROUND

Intestinal obstruction, characterized by the impaired transit of intestinal contents due to various etiologies, constitutes a prevalent surgical emergency. In certain cases, surgical intervention becomes imperative, wherein intraoperative intestinal decompression is frequently necessitated. Ensuring effective decompression while minimizing contamination of the operative field constitutes a pivotal step that exerts a direct influence on postoperative outcomes.

AIM

To assess the clinical efficacy of cannula-assisted decompression techniques employed during intraoperative intestinal decompression procedures.

METHODS

A retrospective cohort analysis of 70 patients diagnosed with small bowel obstruction and treated at the Department of General Surgery, Anqing Municipal Hospital, between January 2023 and November 2024 was performed. Of these patients, 37 underwent cannula-assisted decompression, while 33 received conventional enterotomy decompression. The clinical utility of the cannula-assisted technique was evaluated by comparing intraoperative variables and postoperative recovery indicators between the two cohorts.

RESULTS

The cannula-assisted group exhibited statistically significant advantages over the conventional decompression group in terms of reduced operative duration for intestinal decompression, increased volume of evacuated intraluminal contents, and diminished contamination of the surgical field (P < 0.05). Furthermore, this group demonstrated enhanced postoperative recovery, as indicated by a more rapid return of bowel function – reflected in shortened time to first flatus – and a lower rate of incisional infections relative to the conventional decompression group (P < 0.05).

CONCLUSION

The application of cannula-assisted decompression techniques effectively facilitates intraoperative decompression of the small intestine, reduces procedural duration, mitigates surgical field contamination, and expedites postoperative recovery.

Key Words: Intestinal obstruction; Cannula-assisted decompression; Intraoperative contamination; Surgical site infection; Retrospective cohort study

Core Tip: This study introduces a standardized closed negative-pressure double-cannula technique for intraoperative decompression in small bowel obstruction. Compared to conventional enterotomy, this method was associated with a significantly cleaner surgical field (86.5% vs 63.6% without contamination), greater efficiency (median reduction of 6 minutes in decompression time and 30 minutes in total operation time), and enhanced patient recovery, including a lower surgical site infection rate (10.8% vs 30.3%) and a shorter hospital stay.

INTRODUCTION

Intestinal obstruction is recognized as one of the frequently encountered acute abdominal conditions in surgical practice[1]. Clinically, it manifests as abdominal pain, distension, vomiting, and the absence of flatus and defecation. Radiological evaluations typically reveal intraluminal gas and fluid accumulation, bowel dilation, and edematous changes. In cases where conservative measures such as fasting and gastrointestinal decompression prove ineffective, surgical intervention becomes necessary. During operative management, enterotomy-based decompression is often employed to evacuate intestinal contents, reduce intraluminal pressure, relieve bowel wall edema, and facilitate the restoration of intestinal motility[2-4]. Conventionally, this technique entails a longitudinal incision made in the distal segment of the obstructed bowel, with the contents expressed into an open container. However, this method readily results in contamination of the operative field, thereby heightening the risk of postoperative infection and potentially compromising surgical success[5]. Additionally, the release of malodorous intestinal contents can significantly deteriorate the operating room environment and impose considerable discomfort on the surgical team[6].

In this context, a perforated cannula aspirator was adapted to facilitate the evacuation of intestinal contents via negative pressure suction, thereby ensuring effective intestinal decompression and minimizing contamination of the operative field. This retrospective cohort study aimed to compare the intraoperative and postoperative outcomes of a novel closed negative-pressure cannula decompression technique and conventional open enterotomy decompression in patients undergoing surgery for small bowel obstruction. We hypothesized that the cannula technique would be associated with a lower incidence of surgical field contamination, a reduced rate of surgical site infection (SSI), and a shorter intestinal decompression time.

MATERIALS AND METHODS

Patients

A retrospective cohort analysis of 70 cases with small bowel obstruction admitted to the Department of General Surgery, Anqing Municipal Hospital between January 2023 and November 2024 was performed. Of these patients, 33 underwent conventional small intestine enterotomy decompression (control group), whereas 37 received small intestine enterotomy combined with cannula decompression (cannula group) (Supplementary material).

Inclusion criteria: (1) Adherence to diagnostic and treatment guidelines for intestinal obstruction; (2) Persistence of obstruction-related symptoms despite conservative management; (3) Intraoperative confirmation of obstruction with proximal bowel dilation necessitating decompression; and (4) Provision of informed consent by patients or their family members.

Exclusion criteria: (1) Severe organic comorbidities precluding surgical intervention; (2) Absence of intraoperative need for intestinal decompression due to alternative surgical findings; and (3) Presence of colonic obstruction.

All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Declaration of Helsinki 1964 and later versions. This study was approved by the Ethics Committee of Anqing Municipal Hospital. Informed consent was obtained from all patients enrolled in the study.

Cannula

The device consists of two medical-grade polyvinyl chloride tubes of differing diameters and is designed for single use. The outer tube, measuring 2 cm in diameter, features multiple side perforations at its distal end, which serve to evenly distribute suction force and permit the entry of intestinal contents. The decompression function remains operative even when partial occlusion of the side perforations occurs. The inner tube, with a diameter of 1.5 cm, is designed with a tail end that may be connected to a negative pressure suction tube, enabling convenient replacement. An air inlet is formed at the junction between the inner and outer tubes (Figure 1).

Figure 1 Cannula. Outer tube (purple arrow), internal tube (orange arrow), and side perforations of the tube (blue arrow); the black arrow indicates the junction where air can enter.

Definitions of outcomes

Surgical field contamination was defined as the spillage of intestinal contents into the peritoneal cavity, onto the bowel wall, or onto instrument surfaces.

SSI: Diagnosed according to the Prevention’s National Healthcare Safety Network criteria.

Surgery

All surgical procedures in both groups were performed by the same surgeon (author). Patients in both groups received combined intravenous anesthesia with endotracheal intubation, followed by a standard exploratory laparotomy incision, localization of the obstruction site, measurement of the distance from the obstruction site to the cecum, and small intestine enterotomy for decompression.

In the control group, the conventional intestinal decompression method was employed. Bilateral gauze was applied to protect the small intestine and the operative field. A site located 10 cm distal to the obstruction was selected for decompression. The intestine was stabilized using two silk traction sutures, after which an electrosurgical knife was utilized to incise the intestinal wall directly. Intestinal contents were manually expressed into a curved plate and subsequently transferred to a container. Upon completion of decompression, the intestinal incision was closed with interrupted sutures, and the seromuscular layer was embedded (Figure 2).

Figure 2 Small intestine incision decompression method. A: The small intestine was pulled out of the incision using silk thread. The gauze was placed underneath, and the intestinal tract was cut open; B: The intestinal tube was squeezed segment by segment in the direction of intestinal peristalsis with the index and middle fingers, and the intestinal contents were discharged into the container; C: The intestinal contents were collected in a storage bag and transferred into a measurable container, after which the degree of pressure reduction was calculated.

In the cannula group, a purse-string suture using silk thread was placed at a location 10 cm distal to the obstructed intestinal segment. The intestinal wall was then incised using electrocautery, and a cannula was inserted into the proximal bowel and secured with a single knot. The distal end of the cannula was connected to a negative pressure suction device. Intestinal contents were segmentally advanced toward the cannula and collected in a container. After decompression was completed, the purse-string suture was tightened, and the small intestinal incision was covered by embedding the seromuscular layer (Figure 3).

Figure 3 Small intestine tube decompression method. A: A purse-string suture with a diameter of approximately 1 cm was placed on the small intestine wall; B: Fingers were used to control the proximal intestinal tract as the intestinal wall was cut open the; C: The cannula was inserted, and fingers were released to perform the small intestine decompression.

Intraoperative decompression operation video: Intestinal contents were rapidly evacuated without contamination of the surgical field (Video).

Outcome measures

The primary outcome measures included the number of cases involving contamination of the surgical field by intestinal contents, the volume of decompressed intestinal drainage, the time required for intestinal decompression, total operative time, and length of hospital stay. The incidence of postoperative complications was documented, including intra-abdominal infection and SSI. All patients were followed for a period of 6 months to monitor the occurrence of complications.

Statistical analysis

Continuous variables are presented as median (interquartile range) due to non-normal distribution, and compared using the Mann-Whitney U test. Categorical variables are presented as n (%) and compared using the χ² test or Fisher's exact test, as appropriate. Effect sizes are reported with 95%CI. A two-sided P < 0.05 was considered statistically significant.

The objective of the study was to assess the potential advantages of the double cannula decompression technique. The sample size was determined based on the findings of a preliminary test. Given that α = 0.05 and power = 0.8, the sample size calculation indicated that a minimum of 30 subjects per group would be required to detect statistically significant differences between the cannula technique and the conventional decompression method.

RESULTS

Patient characteristics

There were no statistically significant differences observed between the two groups with respect to age, sex, causes of obstruction, length of the obstructed intestine, and duration of obstruction (P > 0.05; Table 1).

Table 1 Clinical features, n (%).

	Cannula group (n = 37)	Control group (n = 33)	Value of statistics	P value
Age (year) [mean (IQR)]	60 (48, 69)	62 (59, 68)	0.801	0.423
Sex			-	0.051
Male	16 (43.2)	22 (66.7)
Female	21 (56.8)	11 (33.3)
Cause of obstruction			-	0.881
Intestinal adhesions	16 (43.2)	12 (36.4)
Tumor	3 (8.1)	3 (9.1)
Intestinal foreign body	7 (18.9)	5 (15.2)
Inguinal hernia	11 (29.7)	13 (39.4)
Obstruction of intestinal tube length (cm) [mean (IQR)]	270 (250, 300)	280 (260, 300)	0.050	0.960
Obstruction time (hours) [mean (IQR)]	76 (68, 84)	72 (66, 76)	1.009	0.316

IQR: Interquartile range.

Intraoperative situation

The cannula group demonstrated statistically significant advantages across all key intraoperative metrics compared to the conventional group. The time required for intestinal decompression was significantly shorter in the cannula group [10 (9, 10) minutes] than in the control group [16 (15, 17) minutes], with a median difference of -6 minutes (95%CI: -7 to -5; P < 0.001). Furthermore, the volume of evacuated intraluminal contents was substantially greater in the cannula group [700 (680, 750) mL] vs the control group [580 (550, 600) mL], corresponding to a median difference of 120 mL (95%CI: 100-140; P < 0.001). Crucially, the incidence of surgical field contamination was significantly lower in the cannula group [5 (13.5%)] vs the control group [12 (36.4%)], with a relative risk of 0.37 (95%CI: 0.15-0.91; P = 0.026). Consequently, the total operative time was also reduced in the cannula group [150 (140, 160) minutes] relative to the control group [180 (170, 200) minutes], yielding a median difference of -30 minutes (95%CI: -40 to -20; P < 0.001). Detailed intraoperative data are presented in Table 2.

Table 2 Intraoperative situation, n (%).

	Cannula group (n = 37)	Control group (n = 33)	Value of statistics	P value
Operative method			χ² = 1.204	0.548
Intestinal adhesiolysis	9 (24.3)	12 (36.4)
Intestinal resection	16 (43.2)	12 (36.4)
Intestinal anastomosis	12 (32.4)	9 (27.3)
Intestinal decompression time (minutes) [mean (IQR)]	10 (9, 10)	16 (15, 17)	Z = 7.108	< 0.001
Reduced pressure amount (mL) [mean (IQR)]	700 (680, 750)	580 (550, 600)	Z = 7.197	< 0.001
Surgical field contamination			χ² = 4.953	0.026
No	32 (86.5)	21 (63.6)
Yes	5 (13.5)	12 (36.4)
Operative time (minutes) [mean (IQR)]	150 (140, 160)	180 (170, 200)	Z = 6.183	< 0.001

IQR: Interquartile range.

Postoperative recovery and follow-up

Postoperative recovery was notably enhanced in the cannula-assisted decompression group. The time to first postoperative flatus was significantly shorter in the cannula group [58 (56, 60) hours] vs the control group [70 (68, 72) hours], with a median difference of -12 hours (95%CI: -14 to -10; P < 0.001). Similarly, the median hospital stay was markedly reduced in the cannula group [9 (8, 11) days] vs the control group [14 (13, 15) days], resulting in a median difference of -5 days (95%CI: -6 to -4; P < 0.001). The rate of SSI was significantly lower in the cannula group [4 (10.8%)] than in the control group [10 (30.3%)], with a relative risk of 0.36 (95%CI: 0.13-0.98; P = 0.042). No cases of abdominal infection were reported in either group. During the follow-up period, one patient (2.7%) in the cannula group and two patients (6.1%) in the control group were readmitted. This difference was not statistically significant (odds ratio = 0.43; 95%CI: 0.04-4.95; P = 0.598). The comprehensive postoperative outcomes are summarized in Table 3.

Table 3 Postoperative recovery and follow-up, n (%).

	Cannula group (n = 37)	Control group (n = 33)	Value of statistics	P value
First postoperative flatus (hours) [mean (IQR)]	58 (56, 60)	70 (68, 72)	Z = 7.171	< 0.001
Hospitalization days (days) [mean (IQR)]	9 (8, 11)	14 (13, 15)	Z = 5.971	< 0.001
Surgical site infection			χ² = 4.142	0.042
No	33 (89.2)	23 (69.7)
Yes	4 (10.8)	10 (30.3)
Abdominal infection	0	0	-	-
Readmission			-	0.598
No	36 (97.3)	31 (93.9)
Yes	1 (2.7)	2 (6.1)

IQR: Interquartile range.

DISCUSSION

Patients with small bowel obstruction typically present with proximal intestinal dilation, accumulation of gas and fluid, and edema of the bowel wall. Exploratory laparotomy has long been regarded as the standard surgical intervention for intestinal obstruction. Following the removal of obstructive factors, effective intestinal decompression is essential for reducing bowel wall edema, lowering intra-abdominal pressure, and facilitating the restoration of postoperative intestinal motility[7-9]. Conventional decompression techniques often involve open enterotomy, which presents several limitations: (1) Exteriorization of the intestine from the abdominal cavity and incision of the bowel wall elevate the risk of surgical field contamination. In patients with a shortened mesentery, intestinal exteriorization is challenging, thereby complicating the decompression procedure; (2) The need for repeated, alternating manual compression of the intestine aggravates bowel wall edema and negatively impacts the recovery of postoperative intestinal motility[10]; (3) Incomplete decompression frequently results in substantial residual intestinal contents; and (4) The open decompression technique exposes the surgical team to malodorous intestinal effluent, which may significantly impair the operating room environment and potentially affect the health of medical personnel[11,12].

Considering the factors outlined above, a low-cost, time-efficient cannula decompression technique was developed for clinical use. During the design of the cannula, multiple side perforations were incorporated into the outer cannula to facilitate the entry of intestinal contents and to preserve decompression function even when partial obstruction of the side openings occurs. The inner cannula, characterized by a smaller diameter and greater length than the outer cannula, permits air entry and circulation, thereby minimizing mucosal injury caused by negative pressure suction. The distal end can be directly connected to a negative pressure suction device, enabling decompression to be performed under sealed conditions. During the decompression procedure, a purse-string suture is placed at the distal segment of the obstructed intestine, followed by a longitudinal incision approximately 1 cm in length on the intestinal wall. The double cannula is then inserted, and the purse-string suture is secured. The distal end is connected to a negative pressure suction system, facilitating rapid evacuation of intestinal contents through the cannula and achieving effective decompression. The results of this study confirmed that cannula decompression significantly reduced intraoperative time, minimized surgical field contamination, and promoted postoperative recovery. The advantages of this decompression technique can be summarized as follows: (1) Decompression is performed within the surgical field, irrespective of mesenteric length, and intestinal contents are less likely to spill, thereby preventing contamination of the operative area; (2) Negative pressure suction decompression obviates the need for repeated manual compression of the intestine and requires only maintenance of an untwisted proximal bowel and gentle propulsion of contents; (3) The decompression effect is comprehensive, with a marked increase in the volume of intestinal contents removed; (4) Decompression efficiency is high, contributing to a significant reduction in operative duration; (5) No offensive digestive fluid odors are released during decompression, preserving the sterility and comfort of the operating environment for medical personnel; and (6) The cannula materials are simple, readily assembled, and cost-effective.

Several considerations should be addressed during the implementation of the cannula decompression technique: (1) Negative pressure suction should be maintained between 0.02 MPa and 0.04 MPa; insufficient pressure may impair the effectiveness of decompression, whereas excessive pressure can readily lead to mucosal adhesion and subsequent injury to the intestinal lining; (2) In patients with a high content of food residue in the intestinal lumen, cannula obstruction may occur. In such cases, the cannula may be externally cleared through the intestinal wall during the procedure, and replacement should be performed if necessary; (3) In cases complicated by intestinal necrosis, decompression should be conducted prior to intestinal resection to prevent peritoneal contamination caused by intestinal content spillage during anastomosis; and (4) This technique poses significant challenges when applied in the setting of colonic obstruction, with a notably high incidence of tube occlusion.

In this study, the cannula decompression technique was primarily employed to manage the accumulation of fluid and gas in the proximal obstructed bowel. Its primary advantage lies in the efficient and clean reduction of intraluminal pressure, a benefit universally applicable to all types of mechanical intestinal obstruction[13,14]. However, the application strategy and specific focus of its advantages may vary depending on the underlying etiology. It is crucial to emphasize that the treatment of the primary cause remains equally important, such as herniorrhaphy, adhesiolysis, and resection of intestinal tumors. The cannula decompression must be underscored as an adjuvant technique that must be employed in conjunction with definitive surgical procedures addressing the root cause of the obstruction.

The findings of this study illustrate the clinical advantages of the cannula decompression technique in small intestine decompression surgery. Nonetheless, several limitations should be acknowledged. First, a larger sample size and an extended postoperative follow-up period are necessary to accurately assess the recurrence of small bowel obstruction following patient discharge. Second, due to the inherent limitations of retrospective cohort study designs, randomized controlled trials are planned to further validate the clinical efficacy of this technique.

CONCLUSION

In this single-center retrospective cohort study, the use of a cannula-assisted decompression technique was associated with superior intraoperative efficiency and reduced surgical site contamination compared to conventional enterotomy. These findings suggest it is a viable and promising alternative for intraoperative decompression in small bowel obstruction, warranting validation in larger, prospective studies.

ACKNOWLEDGEMENTS

The authors sincerely thank all the patients who participated in this study. We also extend our gratitude to the nursing staff and surgical teams of the Department of General Surgery, Anqing Municipal Hospital, for their invaluable support and collaboration in patient care and data collection. We are also grateful to colleagues in the Department of Gastroenterology for their clinical input.