Hi Lamiaa, thanks for bringing this topic up. From what others have mentioned, it can be seen that the problems that arise from insufficient design control are significant. I wanted to give a couple of examples of medical device failures that have occurred in this year and led to recalls:

1. The company HeartWare recalled their Ventricular Assist Device Controllers because there were loose connectors that could have inhibited its alarm from sounding, making the pump stop working.

2. St. Jude Medical recalled a few models of the Fortify, Unify, and Assura ICDs and CRT-Ds because of rapid battery failure caused by deposits of lithium on the battery.

3. Cook Medical recalled Roadrunner® UniGlide® Hydrophilic Wire because the hydrophilic coating has potential contamination by glass particles.

There are more examples of recalls that you can find on the FDA website.
http://www.fda.gov/MedicalDevices/Safety/ListofRecalls/ucm480134.htm

Sufficient design controls are made to reduce the chance of product recalls. This way, the company can prevent any major time and money loss for their products.