Limitations of the First Generation Approach Sample Clauses

Limitations of the First Generation Approach. While the initial findings of MR guided DBS implantation have been very positive, there remain substantial technical and clinical limitations that affect the achievable accuracy, precision and likelihood of dissemination to centers with less clinical and technical expertise. These limitations fall into the following categories: o Trajectory Guide - The present trajectory guide has several key flaws that must be addressed. The physical dimensions of the guide can be problematic when performing bilateral procedures. This frequently required selection of a more lateral burrhole site than desired and occasionally required physical adaptation of the trajectory guide base. The design further requires that the alignment indicator be removed and replaced with an MLI when transitioning between alignment and insertion. Trajectory guide orientation can be affected by this swap and the MLI may not seat correctly when inserted. These limitations were thought to affect several cases where the initial brain penetration was not ideal. The requirement to lean into the bore to adjust the device while monitoring the in-room monitor also proved to be challenging for some surgeons. Finally, the ability to make revisions in position after initial mandrel insertion was very limited. The parallel channels that were offset by 3mm offered only course adjustment and were used in only two leads where the initial accuracy was very poor. The alternative of re-aligning was also not desirable as there was no ability to dial in an appropriate correction. Thus, mandrels whose position was less than ideal were occasionally accepted due to a lack of confidence that substantially improved positioning could be achieved on a subsequent insertion. o Software Interface - Our initial SW was based on the tools available on the Philips scan prescription and image review platform. Numerous work-arounds and significant attention to detail were required to assure that the desired methodology was realized. For example, determination of the position of potential targets with respect to the mid-point of AC-PC was tedious and time consuming. When exploring potential burrhole sites, it was also difficult to adequately visualize structures that would be intersected on the resulting path to the target. The methodology for finding the selected burrhole site was unnecessarily complicated and may benefit from a surface grid and software to indicate the desired burrhole location on the grid. There were additional...