The main aim of this study was to assess the utilization of Parkland Grading Scale system to determine the difficulty level during LC. Our study included 206 patients who underwent LC. Only in 1.5% of the Parkland Grading Scale grade 1 patient, the difficulty of surgery was rated as difficult. Among Parkland Grading Scale grade 2, 2.7% were rated as difficult and 1.3% were rated as very difficult respectively. In Parkland Grading Scale grade 3, 26.2% and 4.85% of the surgeries were rated as difficult and very difficult respectively. In Parkland Grading Scale grade 4, the difficulties of surgery were rated as difficult and very difficult in 33.3% each. In Parkland Grading Scale grade 5, 57.1% was labeled as difficult while 42.9% was labeled as very difficult. The results showed that the rate of surgical difficulty level increases with the increase in Parkland Grading Scale grade (p value < 0.001). Till now only 4 studies has been published in the literature [26, 29,30,31]. Only Madni et al. have categorized the difficulty of surgery for each Parkland Grading Scale grade [31]. They reported in Parkland Grading Scale grade 1, only 1.7% was rated as difficult. In Parkland Grading Scale grade 2, 4.4% were rated as difficult. In Parkland Grading Scale grade 3, 12.7% and 3.9% were rated as difficult and very difficult respectively. In Parkland Grading Scale grade 4, 50% were rated as difficult while 14.3% were rated as very difficult. In Parkland Grading Scale grade 5, 32.4% were rated as difficult and 59.5% were rated as very difficult. There was significant statistical difference in the difficulty of surgery as Parkland Grading Scale grade increases which were consistent with the current study. Above findings suggest that Parkland Grading Scale system is feasible to assess the difficulty level of LC. If the resident or junior surgeon is performing the LC, it guides them to seek early help from the senior for GB with high Parkland Grading Scale grades. It also guides the senior experienced surgeon for early conversion into open surgery and early replacement as main operating surgeon for GB with the high Parkland Grading Scale grades.

In our study, there was significant association of Parkland Grading Scale with the GB decompression, bile spillage, help needed from senior, drain placement, conversion rate and operative time. Our overall conversion rate was 5.8% and only 3(1.4%) patients underwent subtotal cholecystectomy. Madni et al. reported only 9(2.8%) were converted to open surgery which was lower than our report [31]. The possible reason may be due to differences in the expertise of a surgeon. In our present series, the conversion rate in Parkland Grading Scale grade 1, 2, 3, 4, and 5 was 1.5%, 1.3%, 7.1%, 26.7%, and 42.9% respectively. This reports that as the Parkland Grading Scale grade increases the conversion rate also increases. This suggests the increase in level of difficulty of surgery as the Parkland Grading Scale grade increases. Madni et al. reported that, there was no conversion to open surgery in Parkland Grading Scale grade 1, 2, and 3 while the open conversion rate in Parkland Grading Scale grade 4 and 5 was 3.8% and 21.6% respectively [31]. Abdul et al. reported no cases were converted to open surgery [30]. Baral et al. also reported there was no open conversion in Parkland Grading Scale grade 1 and 2 while the open conversion rate for Parkland Grading Scale grade 3, 4, and 5 were 7.6%, 25%, and 100% respectively [26]. Even the open conversion rate for different Parkland Grading Scale grade was variable, there was significant statistical difference in open conversion rate as the Parkland Grading Scale grade increases which was consistent with our study. (p < 0.001) (Table 3). This report suggests that during LC when high Parkland Grading Scale grade is graded we have to alert the whole operating team for possible conversion into open surgery. This also predicts increase in the difficulty level of the surgery. The present study reports that there was significance difference of total operative time with the increase in Parkland Grading Scale grade. The median time for Parkland Grading Scale grade 1, 2, 3, 4, and 5 was 50 min, 55 min, 75 min, 120 and 150 min respectively. The time taken for higher grade is more than 90 min which is considered to be a risk factor for morbidity [32].Similarly Madni et al., Abdul et al. and Baral also reported statistically significant difference in total operative time in relation to different Parkland Grading Scale grade [26, 30, 31]. This finding suggests that as the Parkland Grading Scale grade increases the total operative time increases which will subsequently increase the difficulty level of the surgery.

Several studies have reported various pre-operative scores to predict difficult LC. In their studies they have found that age, male gender, WBC count, BMI, GB inflammation, GB wall thickness, history of abdominal surgery and previous admission for cholecystitis as the pre-operative factors to predict difficulty LC [18, 19, 21, 33,34,35,36]. Among them Strasberg et al. has pointed out GB inflammation as the most common reason for conversion to open cholecystectomy [34].In our present research, male, BMI, history of cholecystitis, GB wall thickness and pericholecystic collection were significantly associated with higher grade of Parkland Grading Scale whereas age, WBC count, total bilirubin, ALT, AST and history of previous surgery were not associated with higher Parkland Grading Scale grade. Lee et al. have compared the Parkland Grading Scale grading with preoperative factors. They reported that there was statistically significant difference in different Parkland Grading Scale grading in relation to the age, male gender, and WBC count while there was no difference in relation to BMI (p = 0.155) [29]. Similarly, Madni et al. (p = 0.0001), Abdul et al. (p = 0.0001), and Baral et al. (p = 0.0001) reported there was statistically significant difference in WBC count which was not reported in our study [26, 30, 31]. There was similar finding reported by Abdul et al. with relation to GB wall thickness and Parkland Grading Scale grading which was statistically significant [30].From these results, we can assume that the Parkland Grading Scale is as feasible as the pre-operative factors to predict the difficult LC. We believe the inflammation of the GB seen intra-operatively is more vital than the USG findings because it is simple and covers wider range of difficulty variation.

Regarding the post-operative outcomes, there was no significance in incidence of post-operative pneumonia, post-operative bile leak while the incidence of SSI, post-operative fever, and total length of post-operative stay significantly increased with Parkland Grading Scale grading. Even though we had 44(21.4%) patients with bile spillage during the surgery due to iatrogenic GB perforation, there were only 5(2.4%) patients with SSI. This may be due a thorough washing intra-operatively under clear vision. There was no SSI in the patients whose surgeries were converted to open. In our study, 3 (1.4%) patients had post-operative bile leak and there was no significant difference in co-relation to increase Parkland Grading Scale grading. Madni et al. reported 5 (1.5%) patients and Baral et al. reported 3 (1.6%) patients with post-operative bile leakage but in contrast to our study, it was statistically significant as the Parkland Grading Scale grade increased [26, 31]. Our median post-operative total stay was 2 days. Madni et al. and Abdul et al. reported significant difference in post-operative total stay as the Parkland Grading Scale grade increased which was consistent with our study [26, 31]. From all these findings, we can conclude that Parkland Grading Scale system plays important role in determining the post-operative outcomes.

There were some limitations of the study. This was a single centered study. We need to conduct multi-institutional study in larger scale to further validate the Parkland Grading Scale system.