Implanted Drug Delivery System

Sterling Medical Devices designed and developed a Class III pain medication delivery system for patients with spinal injuries. The system is comprised of three devices: an implantable pump, a handheld Clinician Programmer, and a handheld Patient Therapy Controller. The pump is surgically implanted into the patient, and the two handheld devices each communicate with the pump when held within close proximity of it. The system allows a clinician to prescribe a patient with a certain dose of pain medication based on the type and concentration of the medication. It also allows the patient to self-administer a limited number of additional boluses per day on a prescribed basis in order to prevent the need for frequent clinical visits.

Sterling Medical Devices provided product design services for this project. The client requested a complete redesign of the predicate Clinician Programmer. To be aligned with a competitive device on the market, the client requested that the design of a Patient Therapy Controller also be conducted in parallel with the redesign of the Clinician Programmer. Verification of both devices was conducted by Sterling Medical Devices. In addition, Sterling Medical Devices assisted in the validation of both devices.

Challenge

The predicate clinician programmer’s user interface was very limited in its design due to the outdated technology used in the device. The predicate device contained a display screen without touchscreen capability. Navigation to the various screens was done via a set of dedicated keys which were very cumbersome to navigate and unintuitive for the user. In addition to the unintuitive user interface, the electrical hardware in the predicate Clinician Programmer design was outdated. Because of these reasons, a complete redesign of the device was requested with the constraint that the device make use of the existing communication method to interface with the pump. This design constraint ensured that there were no requirements for a redesign of the implantable pump.

Time to market was critical to the client and Sterling Medical Devices worked closely with the client to complete design tasks in several phases. The initial release of the new clinician programmer served as a one-to-one replacement for the predicate device along with a few new features.

The Patient Therapy Controller had to be designed as a home HealthCare device where patient safety, and ease of use were also seen as critical design constraints. The Patient Therapy Controller also used the same communication method to the pump as the Clinician Programmer.

Process

Sterling Medical Devices lead the product development lifecycle management for both devices. The updated Clinician Programmer is comprised of three components: an off-the-shelf commercial smartphone, a Sterling-designed printed circuit board, and a telemetry coil. The smartphone communicates with the main printed circuit board via Bluetooth, while the circuit board communicates with the pump using the telemetry coil. The user interface is entirely contained on an application preloaded onto the smartphone during the manufacturing process. The application is automatically launched at startup and programmatically restricts users from exiting into the mobile OS.

For increased manufacturing efficiency of the Patient Therapy Controller with respect to the Clinician Programmer, the design of the proprietary circuit board used to communicate to the pump was reused and the off-the-shelf commercial smartphone was replaced with a simple LCD screen that mates directly with the circuit board. Because the functionality of the Patient Therapy Controller is quite simplified with respect to the Clinician Programmer, the LCD display was deemed to be a cost-effective replacement.

The design work for both projects was broken up into the following phases:

Phase 0
Sterling outlined the physical aspects of each of the devices (size, shape, etc.). Initial design work began which included wireframe UI and prototype development. In the case of the Clinician Programmer, the client was then taken through the user experience of the predicate device in order to determine the requirements for the design of the updated device.

Phase 1
Sterling worked with the client to create a set of requirements that outlined the overall device functionalities. The features were categorized by relevance to core functionality to ensure that the client’s main features were done first.

Phase 2
Sterling developed prototypes of the devices which included all of the electrical, mechanical, and software aspects. Both designs were iterated and reviewed with the client through a collaborative review process in order to ensure that the device met the clients’ requirements. Via a formal study, users were introduced to the devices to ensure that the users’ needs were being met. Updates based on these studies were incorporated into the devices.

Phase 3
Final pre-production devices were completed. Sterling verified the product designs and finalized testing of the devices. Next, the design validation portion was conducted which included a summative study for each device in conjunction with the client. During each study, users throughout the country were taken through the user interface to ensure alignment with the user requirements and all user safety risk mitigations were proper. The devices were both well received by the users involved with the human factors studies. These users found no difficulty in utilizing the interfaces and were able to easily understand the tasks asked of them. No user risk issues were identified during the studies.

Phase 4
After the successful completion of these studies, both products underwent a design transfer phase whereby the completed design history file was sent to the client for their use as part of a regulatory submission.