RISK FACTORS FOR REOPERATION, MORBIDITY, AND MORTALITY IN PATIENTS WITH SMALL BOWEL OBSTRUCTION SUBMITTED TO SURGICAL TREATMENT

ABSTRACT - BACKGROUND: Small bowel obstruction (SBO) is a frequent cause of emergency department admissions. AIM: This study aimed to determine risk factors of reoperations, postoperative adverse event, and operative mortality (OM) in patients surgically treated for SBO. METHODS: This is a retrospective study conducted between 2014 and 2017. Exclusion criteria include gastric outlet obstruction, large bowel obstruction, and incomplete clinical record. STATA version 14 was used for statistical analysis, with p-value <0.05 with 95% confidence interval considered statistically significant. RESULTS: A total of 218 patients were included, in which 61.9% were women. Notably, 88.5% of patients had previous abdominal surgery. Intestinal resection was needed in 28.4% of patients. Postoperative adverse event was present in 28.4%, reoperation was needed in 9.2% of cases, and a 90-day surgical mortality was 5.9%. Multivariate analysis determined that intestinal resection, >3 days in intensive care unit (ICU), >7 days with nasogastric tube (NGT), pain after postoperative day 3, POAE, and surgical POAE were the risk factors for reoperations, while age, C-reactive protein, intestinal resection, >3 days in ICU, and >7 days with NGT were the risk factors for POAE. OM was determined by >5 days with NGT and POAE. CONCLUSIONS: Postoperative course is determined mainly for patient’s age, preoperative level of C-reactive protein, necessity of intestinal resection, clinical postoperative variables, and the presence of POAE.


ogies of SBO were considered.

Exclusion criteria corresponded to patients with gastric outlet obstruction, large bowel obstruction, medical treatment of SBO, and incomplete clinical record.During the sur
ical procedure, abdominal adhesions were the cause of obstruction (57.3%), followed by internal hernia (16.1%) and abdominal wall hernia (15.1%).Notably, 28.4% underwent intestinal re ection due to necrosis.


Definitions

After the intervention, one-third of the patients had to stay for more than 3 days in ICU.The mean time for the use of NGT was 2.8±4.3 days.Table 2 describes the POAEs from grades 3 to 5, according to the classification of Clavien-Dindo.Reoperation was needed in 9.2% of the patients, due to the following reasons: (1) reobstruction (30%), (2) leak from the enteroenterostomy (35%), and (3) perforation of the small intestine (30%).Mean hospital stay was 12.3±15.9days (range 1-115).OM was found to be 5.9% up to 90 days after surgery.

Table 3 describes the risk factors for the development of adverse effects after surgery for SBO.Multivariate analysis revealed that 7 of 20 variables were statistically significant contributed factors or independent variables for the presence of postoperative complications: age, age >80 years, C-reactive protein >70 mg/L (normal <5), the presence of internal hernia as the cause of obstruction, necessity of intestinal resection, >3 days in ICU, and >5 days of need of NGT.

Table 4 shows the multivariate analysis of risk factors for reoperation after primary surgery for SBO.Out of 33 paramete

, 6 were fou
d to be statistically significant: necessity of intestinal resection, >3 days in ICU, the number of days with NGT, abdominal pain after postoperative day 3, the presence of

AE, and the pres
nce of surgical POAE.

Table 5 demonstrates the risk factors for mortality of patients with SBO submitted to surgical treatment.Out of 27 variables, 7 independent variables had been found to be statistically significant: >5 days with NGT, development of OAE, the presence of surgical POAE, the need for reoperation, the presence of intestinal perforation, the prese ce of anastomotic leak, and the presence of medical POAE.


DISCUSSION

The results of this study suggest the following: 1) There is a change in the causes of SBO, with an increase of internal hernias as the second cause.2) There are several risk factors associated with the complications after surgical treatment of SBO. 3) Several variables can be identified as risk factors for reoperation and OM.

The etiology of SBO has remained similar through decades (2,3,10), with the presence of abdominal adhesions being responsible for nearly 93% of the patients.Approximately 30% of S

occur in the first y
ar after operation and 3% debut with SBO 10 years after initial surgical procedure 18 .In this study, the presence of internal hernias appears as the second cause of etiology, over abdominal wall hernias; this might be probably due to the high incidence of bariatric and oncological procedures with Roux-en-Y reconstruction 14 .The impact of laparoscopic surgery in cumulative incidence of SBO remains unknown; however, with the reduction of adhesions and incisional hernias after minimally invasive surgery, it is probable that internal hernias as cause of SBO may continue to increase.The natural history following adhesiolysis is not completely understood.There is evidence suggesting that SBO may recur up to 32% of patients, with a cumulative incidence of recurrence of 3.7% at 1 year

d 5.8% at
years.

The dilemma of surgical versus medical treatment has been evaluated in several studies 1

,10,19,2
.In one study, up to 60-80% of patients have been resolved conservatively 3 ; but in this study, only 50% were operated on, which is in contrast to our previous study in which nearly 75% of patients were submitted to surgical approach 10 .However, the shorter the hospital stay with conservative management, the higher the chance and the shorter the time to recurrence 1,10,19,26 .Besides, the risk of small bowel ischemia and necessity of intestinal resection in cases with failed medical treatment can be as high as 75% 10 .

Clinical and laboratory examinations have been the classical way to diagnose SBO.The widespread use of triphasic CT has enhanced greatly the diagnosis of complete or incomplete obstruction.To predict better the patient's evolution, international reports have focused on the utility of noninvasive tests such as oral water soluble contrast (OWSC), which has a strong predictive value in defining conservative treatment, with only 3% of surgical necessity in patients with incomplete obstruction 1,8,19 .The impact of OWSC in malignant obstruction has been evaluated in a recent systematic review 23 , thus finding insufficient evidence to determine the need of conservative treatment with this method.

In terms of surgical approach, studies suggested that laparoscopic approach is feasible in nearly 60% of the patients, but with careful selection 22,24 .Several publications 9,15,20 suggested that laparoscopic treatment could be better than laparotomic approach in terms of complications (OR 0.7), incisional complications (OR 0.22), and 30-day mortality (OR 0.55).In the pr sent series, the rate of complications and mortality were 28.4% and 5.9%, respectively, as compared to other publications 15,16,21,22 .

Risk factors for complications after surger

ve been
previously reported.Suter et al concluded that there were no risk factors for intraoperative complications, but accidental bowel perforation (p<0.008) and the need for conversion ( <0.009) were independent variables for an increased risk of POAE (13).This is in contrast with the conclusion suggested by Dindo 11 , in which these variables plu

ASA >2 were significa
t in univariate analysis, but in multivariate analysis only conversion due to intraoperative complication was an independent factor for POAE (OR:3.97).
n contrast, Duron found that surgical adverse effects were associated with the number of obstructed structures (OR:8.3),nonresected intestinal wall injury (OR:5.3),and intestinal necrosis (OR:5.6).Our results demonstrated that age,

nden
factor, as mentioned in a study by Chang 6 .Besides, the need for intestinal resection and prolonged stay in ICU were also independent variables.The finding that C-reactive protein >70 was an important risk factor has not been ev luated in other studies.

Although reoperation is a predominant factor for increased morbidity and mortality, only few studies have reported this fact.Our study had a value of 9.2%, as compared to other studies 5,10,17,22 This study is the first to report on the multivariate analysis of reoperation risk factors in those who were surgically treated.

The actual OM of our study was 5.9%, similar to other series 10,12,17 .However, this study only included surgically treated patients, who usually have a worst condition compared to medically treated cases.Other publications have shown that age, preoperative functional status, ASA stage, medical complications, mixed mechanism of obstruction, intestinal resection, malignant etiology, and reoperation influence OM significantly 6,7,12 .In our series, we found that only postoperative variables determine OM.

There are several limitations in this study: (1) it is a retrospective analysis with all the bias; (2) the laparoscopic group represent a small fraction of the entire cohort and therefore were excluded from the analysis; and (3) there is no longer follow-up in order to determine recurrence of SBO.


CONCLUSION

The findings of this study suggest that postoperative course of a patient with SBO submitted to surgical treatment is determined by patient's age, preoperative C-reactive protein level, necessity of intestinal resection, and the presence of POAEs.


DISCLOSURES

Dr. Manuel Figueroa-Giralt, Dr. Andrés Torrealba, Dr. Tomás Gonzalez, Miss Paula Almeida, Dr. Italo Braghetto, and Dr. Attila Csendes have no conflict of interest or financial ties to disclose.



O tratamento de escolha para pacientes com hipertensão portal esquistossomótica com sangramento de varizes é a desconexão ázigo-portal mais esplenectomia (DAPE) associada à terapia endoscópica.Porém, estudos mostram aumento do calibre das varizes em alguns pacientes durante o seguimento em longo prazo.

HEADINGS: Schistosomiasis mansoni.Portal hypertension.S