Surgical intervention of a normal appendicitis exposes patients to unnecessary anesthesia and surgical complications, and this may be resulted from improper clinical evaluation, and lack of diagnostic methods. Despite the high incidence of acute appendicitis and use of laboratory markers and imaging modalities, the accurate diagnosis remains challenging. Research of the diagnostic process used for acute appendicitis is highly dynamic, within this context information such as novel inflammatory biomarkers is constantly reported in the literature (14). As in our country, high rates of appendicitis cases have been reported in some other countries (15). Therefore, more effort should be made in order to reduce the incidence of NAR and its complications on patients and hospitals (16). Negative appendectomies lead to both postoperative complications, increased morbidity and mortality rates and costs. Thus, investigation of the factors leading to negative appendectomies is of paramount importance. Among these factors, laboratory parameters take an important place. However, to our knowledge there is no consensus in the literature on this subject. In our study, we first evaluated laboratory values between positive and negative appendectomy cases.
We performed preoperative computed tomography by excluding elderly patients, pediatric patients and those with comorbidities. We observed that the rate of negative appendectomy was lower in patients who underwent CT (24.3%). In a study by Wagner et al., the rate of performing preoperative CT raised to 95% from 32% within 10 years (17).
In our study, 84.6% of female patients were found to have a gynecological examination. In a study by Joshi et al. 57.1% of female patients were reported to have gynecological examination (16). We believe that higher gynecological examination rate in our study resulted from the necessity of transvaginal ultrasound in addition to abdominal ultrasound in cases of suspected gynecological diseases in young women in order to reduce the incidence of negative appendectomy.
Recently, although diagnostic value of laboratory parameters such as MPV, RDW and NAR has been evaluated in patients with suspected appendicitis, results of these studies are highly controversial (18).
MPV is a measurement of thrombocyte size that is obtained as a part of routine complete blood count and is usually overlooked by clinicians (19). Changes in platelet counts can lead to changes in MPV. The size and activity of platelets can be influenced by cytokines such as interleukin IL-3 and IL-6. Elevated MPV levels have been reported in several diseases including chronic obstructive pulmonary disease (COPD), myocardial infarction, diabetes mellitus and high altitude (20). Increases in MPV levels are associated with chronic diseases, while decreases are related to acute diseases (21). In our study, the mean MPV value was not statistically significantly lower in both the PA group and NA group. Although there are a few studies about the role of MPV in acute appendicitis, the results of these studies are variable(20, 22). In a study comparing the healthy control group with patients having acute appendicitis, MPV level was found to be significantly lower in the acute appendicitis group. In the same study, it was emphasized that MPV level should not be overlooked in suspected acute appendicitis cases (20). In another study, a significant reduction was found in MPV level of patients with appendicitis (23). In a study by Uyanik et al., no statistical significance was observed in MPV levels of patients with acute appendicitis (22). In another study, higher MPV levels were found in patients with acute appendicitis compared to the control group (18). In a meta-analysis of five studies including 2101 patients with acute appendicitis, it was reported that MPV can be used as a biomarker for the diagnosis of positive appendicitis and is a rapid and inexpensive indicator (24). In our study, in the gender-based evaluation, MPV values were statistically significantly lowered only in male patients in the PA group. Based on our findings, we believe that MPV values under the lower normal range may be affected by gender and requires further evaluation to be used as a biomarker for positive acute appendicitis.
Recent studies have investigated the relationship between hyperbilirubinemia and vermiform of inflammation, and some of these studies have reported that bilirubin can be used as a specific marker of appendiceal perforation (25, 26). In our study, TBIL levels were significantly higher in the PA group compared to the NA group (Table 2). However, in gender-based evaluation, TBIL levels were significantly higher in male patients both in PA and NA groups. In a study by Akbulut et al., a TBIL cut-off ≥ 0.67 is an independent factor predicting acute appendicitis (27). Therefore, our study supports the latest literature in line with our findings. In addition, although the high CRP value in acute appendicitis has been reported in various studies,(13, 28) our outcome of high CRP values in the PA group supports the literature. Although there are several studies about the use of various laboratory markers in the diagnosis of acute appendicitis that were mentioned above, there is still no scientific evidence on the use of blood parameters in predicting acute appendicitis. At this point, it seems possible that NA ratios can be reduced by correlating more than one laboratory data.
In imaging examination, one of the most important findings for the diagnosis of acute appendicitis is appendicitis diameter. In the present study, appendicitis diameter was statistically significantly higher in PA group than in NA group (Table 4). Similarly, in a study by Katipoglu et al., the mean appendicitis diameter was significantly higher in the positive appendectomy cases (29).
The main limitations of this study are its retrospective design and being conducted in a single center. However, the number of our patients is relatively higher than the other studies in the literature. In addition, unlike the other studies in the literature higher MPV (female group) and TBIL values in the positive appendectomy cases will bring a new projection to the literature.