Single-use medical instruments are intended by the manufacturers for single-use only or for single-patient-use only. Nevertheless, single-use instruments are being reused more than once in many countries around the world. The reasons are mainly economic in developing countries and environmental in developed countries. Concerns are being raised regarding reused instruments sterility and efficacy. Since there is paucity of evidence on safety of multiple use of single-use instruments in surgery, we decided to conduct a clinical study comparing the same surgical procedure performed with new versus reused surgical instrument. We decided to study laparoscopic appendectomy which is a simple and the most common emergency surgery. Instrument under the scrutiny is ultrasonic scalpel which uses high-frequency ultrasound vibration for coagulating and cutting tissue. In the studied period of time, all eligible patients with acute appendicitis will be randomized in two groups, first having surgery with new device and the second having surgery with reused device. Removed appendix will be analyzed for lateral thermal damage and the patients will be followed-up for one month for potential differences in clinical outcomes like pain-killers consumption, length of stay and postoperative complications.

Laparoscopic appendectomy provides enhanced recovery at increased costs due to a need for a specific sophisticated equipment. Currently many of the commonly used devices are labeled by manufacturers as single-use only. This trend has stronghold in concerns about patient safety, especially about prevention of cross-infections and other safety-related issues. On the other hand, surgery costs are increased exponentially. There is paucity of evidence on safety of reusing single-use devices (SUD) in surgery. Reuse of SUD which may include refurbishing or reprocessing and resterilization is a complex issue with moral, technical, economical and environmental repercussions. There are several papers discussing the ethical dilemmas involved. The reprocessed instruments are generally deemed equally safe as new one. However there are only few experimental and clinical studies on this topic. Most of them are influenced by sponsors or manufacturers and therefore biased. What's more their conclusions are sometimes highly controversial. Goal of this study is to provide solid evidence on safety of reuse of SUD and to discover differences in in-vitro and clinical outcomes. One of the most common SUD for laparoscopic surgery is ultrasonic scalpel which uses high-frequency jaw vibration which simultaneously coagulates and divides structures with minimal thermal damage to surrounding tissue. One of the best known ultrasonic shears intended for single-use is harmonic scalpel (Ultracision® Ethicon EndoSurgery, Johnson&Johnson Company). Ultrasonic shears are being refurbished and/or resterilized for repetitive use in limited number of cycles or until become dysfunctional or disintegrate. Routine depends on local regulations and variations in practice. To encourage or to ban aforementioned practice we need solid evidence based on properly conducted clinical trial. Therefore we have designed a single-blind randomised clinical trial depending on virginity of instrument used for tissue dissection. Since Ultracision device is the most commonly used ultrasonic sealing device we decided to study outcomes of surgery performed with the new (unused) instrument versus resterilized reused instrument.

All of the patients with clinical and radiological suspicion of having acute appendicitis will be blindly allocated in two arms according to the predefined random sequence provided by independent statistician. Eligible patients will sign an informed consent form. First arm will have laparoscopic appendectomy with new ultrasonic device. The patient will be blinded for the allocation, but the surgeon can not be blinded since packing of the new and reused instruments differ. Even if the scrub nurse would give surgeon instruments without packing, some minor damage might be seen on the plastic coating of the instrument jaws. The second arm will have laparoscopic appendectomy with reused ultrasonic device. All other treatment including surgical technique, postoperative management and follow-up will be unchanged or within the standard of care. Surgical technique is standardised three-trocar approach in general anesthesia. All other details of the surgery are variable depending on local findings, extent of inflammation, anatomy variations etc. Removed specimens will be analyzed routinely with addition of measurement of lateral thermal damage of mesoappendix and appendiceal base. Patients will be screened for antibiotic therapy length, analgesics consumption, early surgical complications according to Clavien-Dindo classification and length of stay. Additionally one month follow-up will be conducted to pick-up possible late complications or readmissions. Study will be conducted in two centers for a period of time until sufficient number of participants are recruited.

Inclusion Criteria:

• Clinical diagnosis of acute appendicitis confirmed during surgery
• Laparoscopic appendectomy
• Operated with UltraCision harmonic scalpel.

Exclusion Criteria:

• Finding of innocent (white) appendix
• Pregnancy
• Significant co-morbidity (ASA III-IV)
• Open appendectomy
• Laparoscopic appendectomy using instruments other than Ultracision harmonic scalpel.

Participants will be blinded to allocation and instrument used for surgery, with the same clinical treatment and postoperative follow-up.