Despite being demonstrably better than conventional surgical techniques with regards to implant alignment and outlier reduction, computer navigation systems have not faced widespread adoption in surgical operating rooms. It is believed that this is in-part due to the bulky design of the optical tracker assemblies which must be rigidly fixated to a patient’s bone and thus occupy a significant portion of the surgical workspace. The problem motivated Mark Semple (Surgical Technologies Laboratory) to develop a novel flexible pin technology, FlexiPin, that uses significantly more compact and less cumbersome trackers to achieve reliable surgical navigation. Despite its advantages, the FlexiPin’s working principle requires multiple small tracker pins to be fixed on a patient’s bone. To negate this potential drawback, an efficient and safe percutaneous pin anchor insertion solution, the tracker insertion gun, was developed from a joint effort of my colleague at Surgical Technologies Laboratory and I. I played an instrumental role in re-designing the prototype for fabrication. I also fabricated a functional prototype of the device and verified the effectiveness of our concepts.

Orthopaedic Navigation Tracker

Insertion Gun

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The tracker insertion gun is a hand-held device at a length of approximately 30 cm. It was designed so that the charging and firing actions can be performed by a user without any assistant.

 
 
 
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Flexible Tracker Pins

The novel optical tracker system developed by Mark Semple uses a set of low-profile flexible pins that can be placed into a rigid body and individually deflect without greatly affecting the pose estimation. He used a Kalman filter based algorithm as a recursive body pose estimator that can account for relative marker displacements. This approach eliminate the need of a traditional bulky optical tracker.

 
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Pin Anchor Insertion Made Easy and Safe

The tracker insertion gun uses a spring loaded impactor to deliver energy required for insertion. Charging can be performed easily by the user. Various firing power can be selected by varying the stopping height of the impactor during the charging phase.

The anchor pin holder serves as a safety mechanism that prevents accidental pin fly-off. It can also recess the pin into the gun body prior to firing (after acquisition of the insertion location). This function allows the user to brace the flat gun tip against the patient’s skin for improved stability. The physical prototype components were all fabricated in-house using CNC machine, water-jet cutter, lathe , and milling machine.

Other Functionalities

 
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Device Photo Coming Soon…..

The physical prototype also includes a custom-designed charging grip. The grip can be securely locked to the tail of the impactor rod and provides ergonomic gripping experience while users carry out the charging action.

 
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Device Photo Coming Soon…..

A novel safety feature, the anchor pin holder, securely holds the anchor pin until the pin release lever is engaged. This prevents the sharp anchor pin from becoming a projectile when a misfiring occurs.

 
 
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Laser Surgical Drill Depth Guide