Acute appendicitis remains one of the most frequent surgical emergencies. While laparoscopic appendectomy offers advantages including reduced postoperative pain, quicker recovery, and shorter hospital stay, it carries a risk of intraoperative conversion to open surgery, particularly in complicated cases [1-3]. Conversion increases operative time, complications, and cost [4]. Identifying preoperative predictors of conversion can improve patient selection, surgical planning, and outcomes. Among imaging findings, the outer diameter of the appendix has shown promise in distinguishing uncomplicated from complicated appendicitis [5,6]. This study investigates whether the pre-operative measurement of appendix diameter on imaging can reliably predict the likelihood of conversion to open appendectomy.

Study Design and Setting A prospective observational study was conducted at Jawaharlal Nehru Medical College, KAHER, Belagavi, from September 2022 to August 2023. Ethical clearance was obtained from the institutional review board. Inclusion and Exclusion Criteria Inclusion: • Age 18–70 years • Clinical diagnosis of acute appendicitis • Undergoing laparoscopic appendectomy • Informed consent provided Exclusion: • Previous abdominal surgery • Diabetes or other comorbidities • Appendectomy as part of another procedure Data Collection Appendix diameter was measured via USG or CT scan. The choice of imaging depended on initial findings and clinical suspicion. Operative notes recorded whether conversion to open surgery was required and the reasons for conversion. (Table 1) Statistical Analysis ROC (Receiver Operating Characteristic) curves were generated using SPSS software to determine the sensitivity and specificity of appendix diameter for predicting conversion. A p-value < 0.05 was considered statistically significant.

Among 63 patients (34 females, 29 males; mean age 43.1 ± 13.6 years), 7 required conversions to open surgery (11.1%). ROC Analysis: • The optimal cutoff for appendix diameter was 8.95 mm (sensitivity 71.4%, 1-specificity 33.9%). • Patients with diameters >8.95 mm had significantly higher conversion rates. • Reasons for conversion included retrocecal position with adhesions, perforation at the base, and abscess formation. Imaging Modality: • CT detected diameters >9 mm in 20 cases. • USG identified only 4 cases >9 mm. Table 1: Reasons for Conversion to Open Surgery Age Group Gender Diameter (mm) Reason 18–28 Male 9.2 Anatomy unclear 29–45 Female 9.0 Retrocecal appendix 46–65 Male 9.2 Abscess >65 Female 9.4 Perforation

This study demonstrates that a pre-operative appendix diameter >8.95 mm significantly increases the likelihood of conversion to open appendectomy. Our findings are consistent with those of Kacprzyk et al. [8] and Akturk et al. [11], who showed that larger diameters are associated with complicated appendicitis. Earlier studies have suggested that imaging, particularly CT, provides reliable measurements of appendiceal diameter [6,7]. Moreover, elevated appendix diameter has been associated with complications such as perforation, phlegmon, or abscess, necessitating conversion to open surgery [5,10]. While laparoscopic surgery is generally safe, it may be less feasible in cases with distorted anatomy or inflammatory mass. Thus, recognizing predictive factors such as appendix diameter helps optimize surgical strategy.

An appendix diameter >8.95 mm is a significant pre-operative predictor for conversion to open surgery. Incorporating this measurement into routine pre-operative assessment could guide decision-making and minimize intraoperative risks. Further studies with larger sample sizes are warranted to validate these findings. Declaration: Ethics Approval and Consent to Participate This study was approved by the institutional ethics committee. Written informed consent was obtained from all individual participants included in the study. Consent to publish Not applicable Data availability Data in the article Conflict of Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Funding Statement The study did not receive any funding from external sources. Abbreviations: USG (Ultrasonography) CT (Computed Tomography) ROC (Receiver Operating Characteristic) KAHER (KLE Academy of Higher Education and Research) JNMC (Jawaharlal Nehru Medical College)

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