Incarcerated inguinal hernias surgical treatment specifics in elderly patients

Background/Aim. Incarcerated inguinal hernias surgical treatment represents one of the most frequent surgical treatments in elderly patients. The percentage of incarcerated inguinal hernias urgent surgical treatments is growing exponentially with the age in patients over 50. The aim of the study was to investigate some of the factors that may have impact on the incarcerated inguinal hernias surgical treatment outcome in elderly patients. Methods. The study included 180 patients classified in two groups: the study group (> 65 years of age) and the control group ( 65), managed in the period from January 2005 till March 2009 at the General Surgery Clinic, Clinical Center Niš. Results. Most of the patients had right inguinal hernia (52.6%, the study group; 59.1%, the control group). All the study group patients suffered from some of accompanying chronic diseases (100%), opposite to 39 (59%) patients of the control group. Synthetic material was implanted in 124 (68.9%) patients, while the tension technique was performed in 65 (31.1%) patients. The duration of incarceration more than 24 h (p = 0.015), previous abdominal surgery (p = 0.001), the American Society of Anesthesiologists physical status classification system (ASA classification) (p = 0.033) and the presence of chronic diseases (p = 0.01) appeared to be statistically significant risk factors for performing intestinal resection in the study group, while in the control group they represented risk factors, but not at the level of statistical significance (p <0.05), except for the duration of incarceration (p = 0.007). A higher ASA stage (p = 0.001) and the presence of bowel resection (p <0.001) are the most important risk factors for lethal outcome in both groups of patients. Conclusion. Incarcerated inguinal hernia in elderly patients is a serious problem. A higher ASA score and the presence of bowel resection are the most important factors related to unfavorable outcome.


Introduction
Due to abdominal wall weakness and conditions that increase intra-abdominal pressure, external hernia is more frequently seen in elderly patients [1][2][3][4] .The estimated incidence of the anterior abdominal wall hernia in patients more than 65 years old is 13 per 1000 5 .Incarcerated external hernia repairs represent one of the most common emergency procedures performed in elderly patients.Emergency hernia repair rates increase exponentially with the age in patients more than 50 years old 6 .Males predominate among the patients up to 75 years of age, while females prevail in the later age 7,8 .More recent data indicate that incarcerated inguinal hernias account for about 20% of all small bowel obstructions.Due to the fact that up to 30% of bowel incarcerations require intestinal resection, emergency hernia repair is also associated with significant morbidity and mortality 5 .Up to 75 years of age, 10-15% of men underwent surgical treatment of hernias.
The aim of the study was to examine some of the factors that may affect the outcome of incarcerated inguinal hernias surgical treatment in elderly patients.

Methods
The study included 180 patients divided into two groups: the study group (> 65 years) and the control group ( 65 years).All tests were carried out in the period from January 2005 to March 2009 at the Clinic of General Surgery, Clinical Center Niš.During the research, the following parameters were tracked: age, gender, type of incarceration (direct/indirect), the ratio of right to left incarcerated inguinal hernia, related chronic diseases (as it is to do with elderly people with degenerative changes in the body organs and systems), the duration of incarceration (0-24 h, > 24 h), The American Society of Anesthesiology (ASA) classification, intestinal resection, type of surgical procedure (autologous tissue-tension technique or repair with prosthetic materialtension-free technique).In statistical analysis for comparing values sorted by the normality type, parametrical tests (Student's t-test, ANOVA -variance analysis with post hock analysis, Bonferroni, Dunnett, Dunnetts T3, Pearson correlation) were used.Analysis of variables not sorted by the type of normality was made by comparing the non-parametrical tests (Mann-Whitney U test, Spearman Correlation, 2 test, Fisher exact probability test the null hypothesis).Analysis of survival was made through Cox Regression models, where univariant "Enter" method was used to determine hazard rate (HR).By means of univariant logistic regression, "Enter" method use, the crude odds ratio-cross ratio (OR) has been defined, the risk factors analyzed variables.The statistical significance was determined at the level of p < 0.05 and implemented by software package SPSS (version 15).

Results
The study included a total of 180 patients of whom 114 were in the study group and 66 in the control group.The patients in the study group (the average age of 71.28 ± 5.06 years), were significantly older than those in the control group whose average age was 49.68 ± 14.54 years.As expected, there was a statistically significant difference in the age of the study group and control group at the level of significance p < 0.001.Out of 114 patients in the study group, 20 (66.7%) had direct and 94 (62.7%) indirect hernia.Of 66 patients in the control group, 10 (33.3%) had direct and 56 (37.3%) indirect hernia.In either of the analyzed groups, no statistically significant differences was observed in the frequency of the occurrence of displayed hernia forms ( 2 : p > 0.05).(Table1).The highest number of patients had a right inguinal hernia (52.6% in the study group and 59.1% in the control group).All patients in the study group suffered from some of chronic diseases (100%), which was significantly more than 39 (59%) patients in the control group (Table 1).
In most cases, the type of surgery in the case of incarcerated inguinal hernia was determined in individual assessment of the surgeons.Of 114 patients in the study group, 45 (39.5%) patients were subjected to tension surgical technique.Among the control group patients, tension technique was applied in 11 (16.7%)patients.Synthetic material was embedded in 69 (60.5%) patients of the study group, and in 55 (83.3%) patients of the control group.It can be asserted, with the error level of p < 0.001 that much bigger statistically important number of the control group patients had synthetic material implanted compared to patients in the study group (Table 2).Owing to univariant binary logistic regression, as a statistically significant risk factor for performing intestinal resection in the study group, there were singled out the duration of incarceration over 24 h (OR = 12 688, 95% CI = 1.64-98.37,p = 0015), previous abdominal surgery (OR = 2119, 95% CI = 0569-5321, p = 0.001), ASA classification (OR = 9344, 95% CI = 1.12-72.82,p = 0.033) and the presence of chronic diseases (OR = 3985, 95% CI = 1236-5695; p = 0.01).Previous analyzed factors in the control group represented the risk factors, but not at the level of statistical significance (p < 0.05), except the duration of incarceration (p = 0.007) (Table 3).
Table 4 shows the summary statistics of Cox regression model and log rank test of patients survival length.The patients' age in the study group did not represent a statistically significant risk factor for lethal outcome (p = 0.381).The length in survival in both study and control group seems not to differ by age (p = 0.356).Gender in the study group did not represent a statistically significant risk factor for lethal outcome (p = 0.327).Also, there was no difference between the groups in terms of the length of survival by gender (p = 0.276).By increasing ASA stage for one, a chance for lethal outcome is increased 10.6 times at the level of significance (p = 0.001).The presence of intestinal resection was a statistically significant risk factor for lethal outcome, increasing the chance 6.4 times (p < 0.001) and the patients with resection had a significantly shorter survival time than those without resection (p < 0.001).The duration of incarceration over 24 h was a statistically significant risk factor for lethal outcome, increasing the chances by 32 times (p = 0.01) and the patients with resection had significantly shorter survival time than the patients without resection (p = 0.024).

Discussion
Strangulation hernia is a condition in which the hernia cannot be returned to the abdomen.By putting emphasis on the increased risk of intestinal obstruction, strangulation incarceration gets a great importance 8 .Incarcerated external hernias are the second most important cause of intestinal obstruction 9 .In elderly people about 40% of inguinal hernias are surgically treated, due to incarceration or intestinal occlusion.Although some earlier studies have presented data that only 5% of all inguinal hernias require urgent surgical care 10 , others have suggested that this percentage is slightly higher and amounts up to 13% 11 .Since the anterior abdominal wall hernia incarceration, followed by incarceration of intestinal curves, is associated with high percentage of morbidity and mortality 10,12 , urgent surgical intervention is necessary.There is a generally accepted view that hernia should be electively managed in order to avoid later complications 13 .However, many patients are undiagnosed, or consciously reject the proposed surgery, that resulting in occurrence of many emergency surgeries, because of "neglected" cases of hernia.Due to the increased risk of postoperative complications in elderly people, surgeons sometimes reluctantly access the management of elective inguinal hernias 1 .Despite the universal acceptance of the importance of hernias elective management, inguinal hernia is still a common cause of acute abdomen 14 .This is not only attributed to the fact that many patients, especially elderly, experience incarceration while on the waiting list for elective surgery 15 , but to the primary factors responsible, such as a large hernia proportion, incarceration (long before a doctor learn about that), the low level of public awareness about the danger of incarceration or just to non-surgical medical staff refusal to speak to the patient about the known risk factors 16 .There were no significant differences in the occurrence frequency of inguinal hernia displayed forms between the groups, as reported by studies done in other healthcare institutions 1,11 .Comparing the prevalence of hernia types in a number of scientific papers, it seems that indirect hernias dominate over the direct ones in the proportion ranging from 7 : 3 to 10 : 1 in favor of indirect hernias 1 .Of 114 patients in this study group, 20 (66.7%) patients had direct and 94 (62.7%) patients had indirect incarcerated hernia.Of 66 patients of the control group, 10 (33.3%) patients had direct and 56 (37.3%) patients indirect incarcerated hernia.There was not more frequent occurrence of indirect than direct incarcerated inguinal hernia, thus no statistically significant difference exsisted in the displayed hernia forms occurrence frequency ( 2 : p > 0.05) in neither of the groups, concering sex, also.
Another important factor, contributing to the unwanted outcome in the patients with incarcerated inguinal hernia, is related to comorbid chronic diseases 17,18 .Moreover, this factor gets a statistical significance when talking about mortality 19 .All the patients in the study group had some chronic diseases (100%) which was statistically more significant than 39 (59%) patients in the control group.Symptoms duration in the study group was accompanied by incarceration duration and lasted from one to three days.Duration increased with the age increase, which could be observed in other studies, too 1 .Late hospitalization is generally considered as an important factor for determining the level of intestinal resection and subsequent morbidity and mortality 10,[20][21][22] .Incarceration and strangulation with or without intestinal obstruction are major complications 23 .Roughly speaking, about 15% of all the patients with incarcerated intestinal curve required resection because of intestinal necrosis caused by strangulation 20,24 .Manual reposition may be the method of choice without resection in incarcerated inguinal hernia, although there are no strict criteria to clearly differentiate strangulation, except the obvious peritonitis 24 .Statistically significantly a higher number of patients studied in both groups without intestinal resection, had incarceration that lasted less than 24 h (50.3% vs 3.4%, p < 0.001).Our observations showed that, according to Cox's regression model and logrank test on the patients with and without intestinal resection, the presence of intestinal resection was a statistically significant risk factor for lethal outcome, increasing the chance 6.4 times and the patients with resection had a significantly shorter survival time than those without resection.Open tension-free technique was the most common surgical technique type as in all previous studies [25][26][27] , and in both tested groups of our study.This technique contributed in managing a total of 124 (68.9%) patients.Taking into account general attitude that synthetic material should not be implanted in patients younger than 30 years of age, because of the netting deformation during a young organism development, as well as because of the surgeons' fear to implant synthetic material in intestinal resection cases due to possible complications, we can argue with the level of error (p < 0.001), that much higher number of patients in the control group, 55 (83.3%), had a built-in synthetic material, than it was the case in the study group, 69 (60.5%).In previous studies on patients with incarcerated inguinal hernias, it has been observed that a high ASA score is an independent predicting factor for small bowel gangrene 28 .Alvarez et al. 19 not only confirmed the higher rate of complications, but also showed a higher rate of mortality in patients with higher ASA grade.In our study, ASA grade was a risk factor for performing intestinal resection, but not at the level of statistical significance.

Conclusion
Thus, incarcerated inguinal hernia in elderly patients is a serious problem, showing how simple surgical problems may have lethal outcome.It carries a high risk of disease developing in the unwanted direction with the pres-Peši I, et al.Vojnosanit Pregl 2012; 69(9): 778-782.
ence of associated chronic diseases.All the patients in the study group had some of chronic diseases.Statistically significant risk factors for performing intestinal resection in the study group patients were duration of incarceration longer than 24 h, previous abdominal surgery, higher ASA classification, whereas in the control group, the only statistically significant risk factor was duration of incarceration for more than 24 h.