Examining Relationships Between Device Complexity and Failure Modes of Minimally Invasive Surgical Staplers
Authors: Riggs Marie K. , Bohm Matt R. , Mountain Philip J. 
Published: February 2017

Minimally invasive surgery (MIS) has become the standard approach for an increasing number and variety of procedures. Designing devices for such surgeries presents many challenges and must address efficiency, accuracy, and ease of use. The complexity of a device’s design likely influences its performance in real life situations. Therefore, identifying the complexity and potential for failures of a device is crucial in the early stage of design in order to ensure the effectiveness and safety of the final product. A complexity measure is explored utilizing design variables such as the maximum number of connections, number of total elements, and number of unique elements within a device. Reverse engineering of medical devices has been completed to begin understanding such complexity variables. The overall objective of this research is to determine the correlation between a medical device’s complexity measure and its failure modes. The nature and frequency of problems associated with various surgical medical devices must be characterized. This paper is an initial investigation and focuses on surgical stapling devices for MIS. The analysis pertains strictly to surgical staplers that simultaneously staple and transect tissue with a design that allows insertion through small incisions via a trocar, wound protector and retractor, or direct insertion.

Adverse event reports involving minimally invasive surgical staplers have been retrieved from the U.S. Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE) database from January 2006 – January 2016 and examined to determine trends in the characterization of device problems and prevalence of such problems. A total of 13,312 reports are included in the analysis. 106 events resulted in death, 3234 resulted in injury, and 9972 involved a device malfunction. A yearly analysis has been conducted analyzing the trends in event type (death, injury, and malfunction) and device brands involved in the reports over the past decade. A sample of reports was taken in order to perform a detailed analysis of the event descriptions. The reports are categorized by phase and description of failure modes associated with surgical stapler use. The phases of use in which failures occur have been identified as packaging, reload, articulation, application, firing, cutting, removal, and staple line. FDA recall information associated with these devices was also investigated.

An extensive study regarding adverse events reported to the FDA associated with surgical staplers has not been completed since 2004 to the authors’ knowledge, nor a study investigating this specific category of surgical stapling devices. These devices are constantly evolving in regards to their design features, and their application is expanding to more wideranging open and MIS procedures. Despite the prevalence of minimally invasive surgical stapler use, any incident of failure may put a patient’s health and safety at risk. Malformed staples as a result of the firing phase, removal issues, and leaking staple lines were the main contributors to surgical stapler failure in the adverse event reports analyzed. Bariatric and thoracic surgery accounted for the majority of procedure types identified within the reports. The range of procedures in the analysis verifies the expansion of surgical stapler use and application. Various failure modes can be attributed to user error; however, the FDA recall information associated with these devices indicates that device failure shares responsibility. The results of this work contribute to the awareness of both surgical stapling device designers and users, and the importance of such must be heavily emphasized in order to prevent future complications in the field.