Maximum Diameter of the Gallbladder Determined Presurgically Using Computed Tomography as a Risk Factor for Difficult Emergency Laparoscopic Cholecystectomy in Patients With Mild to Moderate Acute Cholecystitis : Surgical Laparoscopy Endoscopy & Percutaneous Techniques

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Original Articles

Maximum Diameter of the Gallbladder Determined Presurgically Using Computed Tomography as a Risk Factor for Difficult Emergency Laparoscopic Cholecystectomy in Patients With Mild to Moderate Acute Cholecystitis

Sasaki, Atsushi MD, PhD; Sakata, Kazuhito MD, PhD; Nakano, Koji MD; Tsutsumi, Satoshi MD, PhD; Fujishima, Hajime MD, PhD; Futsukaichi, Takuro MD, PhD; Terashi, Takahiro MD, PhD; Ikebe, Masahiko MD, PhD, FACS; Bandoh, Toshio MD, PhD; Utsunomiya, Tohru MD, PhD, FAC

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Surgical Laparoscopy, Endoscopy & Percutaneous Techniques: October 2022 - Volume 32 - Issue 5 - p 523-527
doi: 10.1097/SLE.0000000000001093
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Cholecystolithiasis is a one of the most common diseases accounting for cases in emergency units of hospitals worldwide.1 Since the 1990s, advances have been made in developing surgical techniques and devices. Among these advances, laparoscopic cholecystectomy (LC) was adapted for use in patients diagnosed with acute cholecystitis (AC).2 Presently, emergency LC is recommended for patients with AC, regardless of the duration since its onset.3 However, such patients frequently experience difficulties during surgery.4

In 2018, Tokyo Guidelines (TG) for the diagnosis and grading of the severity of AC were revised. Following these guidelines, AC was divided into 3 categories according to the condition of the gallbladder and general findings: mild (grade I), moderate (grade II), and severe (grade III).3 Although emergency LC is recommended for patients with mild to moderate AC, nonsurgical initial therapy is recommended for those with severe AC. In clinical settings, most patients diagnosed with AC are classified as having mild (grade I) or moderate (grade II) disease.5

During difficult LC, longer surgical periods, more intrasurgical blood loss, or a conversion to open cholecystectomy are frequently experienced.4 Several authors have therefore investigated risk factors for predicting the difficulty of LC in patients with AC.6–14 As a result, common predictors for analyzing the difficulty of LC for AC have been reported. Among these predictors, gallbladder wall thickening,6–9 cystic duct impaction,7 elevated presurgical C-reactive protein (CRP) level,10–12 higher body mass index (BMI),9,13 sex (male patients),6,14 and interval between onset of symptoms and surgery have been identified.14

Diagnostic modalities for detecting AC have been reported. TG18 recommended ultrasonography as the first-choice imaging method for AC because of its low invasiveness, widespread availability, ease of use, and cost-effectiveness.5 Several investigators also reported that presurgical ultrasonography findings predicted technical difficulties during LC for AC. From these reports, the gallbladder size,7 gallbladder wall thickness,7–9 and the presence of an enlarged common bile duct (CBD) diameter7,8,15 were common ultrasonography-based predictive factors for analyzing surgical difficulty in patients diagnosed with AC. However, ultrasonography-based diagnostic criteria for detecting AC, in addition to its diagnostic yield, vary across different studies.5 Moreover, only a few investigators have reported that computed tomography (CT) was more sensitive for diagnosing AC than ultrasonography.16–18 Hence, the correlation between susceptibility to surgical difficulty during LC and presurgical CT findings presently remains unclear.

Here, we analyzed presurgical predictors, including presurgical CT findings, to detect difficulties in patients with mild to moderate AC undergoing emergency LC.


From April 2013 to August 2020, 79 patients diagnosed with AC, who underwent emergency LC at the Oita Prefectural Hospital, were enrolled. Seven of these patients who had previously undergone presurgical percutaneous or endoscopic gallbladder/CBD drainage and were diagnosed as having CBD stones were excluded from the study. A total of 72 patients were finally enrolled in this study. Subsequently, all patients were classified with mild to moderate AC degree according to the TG18 criteria and were scheduled for emergency LC within 5 days after symptom presentation.

All patients were routinely subjected to presurgical blood chemistry tests and contrast-enhanced or plain thin-slice CT at the time of presenting to our hospital. Abdominal ultrasonography was not routinely performed when CT was performed. Therefore, ultrasonography findings were excluded from this study. On the basis of the aforementioned examinations, the 72 patients were classified into those with mild (n=45) and moderate (n=27) AC, respectively, following the severity grading of TG18.

We also investigated the following presurgical characteristics of the patients: sex, age (years), BMI (kg/m2), interval between symptom onset and surgery (hours), and accompanying diabetes mellitus status. Along with presurgical laboratory parameters, including white blood cell count (/mm3) and CRP level (mg/dL), CT findings, including gallbladder diameter (mm) (Fig. 1A) and wall thickness (mm) (Fig. 1B), stone in the cystic duct (Fig. 1C), and perigallbladder fluid collection (Fig. 1D) were investigated. The gallbladder diameter was measured as the maximum diameter of the gallbladder in the liver’s gallbladder fossa (Fig. 1A). However, gallbladder thickness was measured at the portion of the gallbladder’s body with the maximum thickness (Fig. 1B). Moreover, data regarding the experience of the surgeons (years), surgical duration (minutes), blood loss during surgery (g), as well as postsurgical complications and duration of admission (days) were also collected.

Factors evaluated during presurgical computed tomography. The gallbladder maximum diameter was measured at the gallbladder fossa of the liver (A). Wall thickening of the gallbladder was measured as the maximum wall thickness at the gallbladder’s body (B). A calcified stone identified in the cystic duct (C). Fluid collection observed around the gallbladder (D).

Difficult LC was defined as patients with any following surgical factor: surgical duration ≥180 minutes, blood loss ≥300 g, or conversion to open cholecystectomy, according to definitions from previous reports.14,19

Statistical Analysis

Characteristics of patients who underwent difficult LC were evaluated using the χ2 or Fisher exact tests for nominal variables and the Kruskal-Wallis test for continuous variables. The receiver operating characteristic curve analysis was then performed to define the cutoff value of the factor. Subsequently, the relationship between surgical difficulties and each clinical factor was compared by performing a univariate logistic regression analysis. In addition, P<0.05 was set as the level of significance for all analyses. Moreover, statistical analyses were conducted using JMP software (JMP; SAS Institute Inc., Cary, NC).


The patients comprised of 48 men and 24 women, whose mean age at the time of LC was 60.3 (range: 25 to 88 y). The mean interval between symptom onset and surgery was 40.6 (median: 37.8; range: 5 to 120 h). Furthermore, the mean surgical durations and intrasurgical blood loss were 112.2 (median: 96.5; range: 29 to 296 min) and 55.2 (median: 5.0; range: 0 to 530 g), respectively. In addition, although 5 patients had postsurgical complications (6.9%), no deaths were reported. The different postsurgical complications observed were bile leakage in 2 patients and bile leakage and pneumonia, hyperbilirubinemia, and wound infection in 1 patient each.

The characteristics of patients who underwent difficult emergency LC are showed in Table 1. As shown, 4 patients underwent open cholecystectomy in place of LC because of surgical difficulties. Furthermore, of the 72 patients evaluated, 12 were classified into the difficult group and 60 into the nondifficult group. The mean surgical durations and intrasurgical blood loss were 220.1 (median: 222.5 min) and 188.3 (median: 100 g) in the difficult group; however, these parameters were 90.7 (median: 87.5 min) and 28.6 (median: 0 g) in the nondifficult group, respectively. The average diameters of the gallbladder were 48.4 and 41.8 mm in the difficult and nondifficult groups, respectively. However, when comparing surgical difficulties, presurgical CRP levels, maximum gallbladder diameters, frequencies of postsurgical complications, and postsurgical admission durations were significantly higher in the difficult group than those in the nondifficult group. After receiver operating characteristic analysis, the estimated cutoff value for the gallbladder’s maximum diameter was 43 mm.

TABLE 1 - Characteristics of Patients who Underwent Emergency Laparoscopic Cholecystectomy According to Grade of Difficulty of the Surgery
Factors Difficult LC (n=12) Nondifficult LC (n=60) P
Sex (M/F) M/F 9/3 39/21 0.74
Age (y) 66.8 59.0 0.18
Surgeon experience (y) 1-5 0 11
6-10 3 14 0.26
11- 9 35
Interval between symptom onset and surgery (h) 44.7 39.8 0.54
BMI (kg/mm2) 24.1 24.4 0.88
History of diabetes mellitus +/− 2/10 10/50 1.00
Presurgical WBC (/mm3) 13370.0 11534.5 0.36
Presurgical CRP (mg/dL) 10.78 6.76 0.04
Cystic duct stone +/– 4/8 21/39 1.00
GB wall thickness (mm) 6.57 5.65 0.20
Maximum GB diameter (mm) 48.4 41.8 0.01
Peri-GB fluid +/− 8/4 28/32 0.34
Surgical duration (min) 220.1 90.7
Surgical blood loss (mL) 188.3 28.6
Conversion to open cholecystectomy +/− 4/8 0/60
Postsurgical complications +/− 4/12 1/59 0.002
Postsurgical admission (d) 15.7 5.32 0.009
BMI indicates body mass index; CRP, C-reactive protein; GB, gallbladder; LC, laparoscopic cholecystectomy; WBC, white blood cell.

The results obtained from univariate logistic regression analyses for risk factors that predict surgical difficulty are shown in Table 2. As shown, only the maximum diameter of the gallbladder was significantly associated with susceptibility to difficultly during LC (P=0.02).

TABLE 2 - Univariate Logistic Regression Analysis Results Showing Difficulties Experienced During Laparoscopic Cholecystectomy
Factors P
Sex (male vs. female) 0.51
Age (y) 0.16
Surgeon experience (1–5/6–10/11 y) 0.96
Interval between symptom onset and surgery (h) 0.60
BMI (kg/mm2) 0.73
History of diabetes mellitus (+ vs. −) 1.00
Presurgical WBC (/mm3) 0.24
Presurgical CRP (mg/dL) 0.18
Cystic duct stone (+ vs. −) 0.91
GB wall thickness (mm) 0.30
Maximum GB diameter (mm) 0.02
Peri-GB fluid (+ vs. −) 0.21
BMI indicates body mass index; CRP, C-reactive protein; GB, gallbladder; WBC, white blood cell.


AC is among the most common disease reported in the emergency unit of hospitals. Patients with AC account for 3% to 10% of all patients presenting with abdominal pain20 and about 20% of surgical emergency procedures conducted owing to emergency nontraumatic abdominal conditions.1 Many investigators reported that early LC was recommended for patients with AC because surgical difficulty may occur during delayed cholecystectomy. Lo et al21 reported that patients who underwent delayed LC (>72 h) showed a tendency to high rate of conversion to open cholecystectomy (23% vs. 11%; P=0.174) and a high complication rate (29% vs. 13%; P=0.07) than those in the early LC group. Moreover, according to TG18, emergency LC was recommended for patients with mild to moderate AC, regardless of the duration since its onset.3

Many investigators have reported risk factors that account for the surgical difficulty, conversion to open cholecystectomy, prolonged surgical duration, or postsurgical complications in patients diagnosed with AC. In these patients, risk factors accounting for the experienced surgical difficulties vary and include gallbladder wall thickening,6–8 cystic duct impaction,7 elevated presurgical CRP,10–12 higher BMI of patients,9,13 sex (male patients),6,14 and longer duration between symptom onset and surgery.14 The definition of surgical difficulty in patients diagnosed with AC also varies based on published reports. Among these reports, Inoue et al14 and Hayama et al19 defined surgical difficulty as the following: surgical duration ≥180 minutes, intrasurgical blood loss ≥300 g, or conversion to open cholecystectomy. However, Gregory et al11 defined surgical difficulty as surgical duration >60 minutes, in addition to the conversion to open or subtotal cholecystectomy. In this study, we adopted the criteria of Inoue et al14 and Hayama et al19 for assessing the difficulty experienced during emergency LC in patients with AC.

The gallbladder’s diameter was found to be a risk factor for difficult emergency LC; presurgical CRP levels, thickening of the gallbladder wall, or interval between symptom onset and surgery were not found to be risk factors in our study. In our hospital, a large proportion of patients presenting with AC had a mild (62.5%) disease, and all patients underwent early LC (within 5 d after symptom onset). Therefore, the previously reported factors may be unrelated to the surgical difficulty experienced during emergency LC.

Besides, only a few investigators have reported the use of CT scans for predicting difficult LC in patients with AC. Furthermore, risk factors evaluated via a presurgical CT scan vary. Among these factors, CT attenuation,22 absence of gallbladder wall enhancement, presence of a gallstone in the gallbladder infundibulum,23 edema in the gallbladder wall,13 and dirty fat signs24 have been reported. However, to the best of our knowledge, none of the reports indicated that the maximum diameter of the gallbladder measured via a CT scan was a risk factor for difficult LC in patients with AC. The total number of CT scans conducted was the highest (111 per 1 million inhabitants in 2017) in Japan, followed by Australia (70 per 1 million inhabitants on 2019), according to a report from Organization for Economic Co-operation and Development countries,25 and the number of CT scans conducted have been steadily increasing worldwide. Almost all patients with AC in emergency units can be evaluated using a CT scan. Moreover, a CT scan–based measurement of the gallbladder’s maximum diameter is an easy and objective indicator for the early detection and treatment of patients with AC.


In this study, emergency LC was safely conducted in most patients with mild to moderate AC. However, performing LC might be technically difficult, especially when presurgical CT scans identify severe cases of gallbladder swelling.


The authors thank the professional editors at Enago ( for editing a draft of this manuscript.


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acute cholecystitis; aparoscopic cholecystectomy; difficulty; computed tomography; gallbladder diameter; open cholecystectomy

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