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A modified stereotactic frame as an instrument holder for frameless stereotaxis: Technical note.

Patil AA - Surg Neurol Int (2010)

Bottom Line: This method was used to insert depth electrodes (seven procedures) and gain access to the temporal horn (three procedures).Post-operative scans showed that the accuracy was within 2.5 mm in all three planes for depth electrode placement, and easy access to the temporal horn was obtained in two other patients.This is a simple method to use a stereotactic frame to improve coordinate and trajectory adjustments and provides a better method to stabilize the pointer and the probe-holder during frameless stereotactic procedures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Neurosurgery, University of Nebraska Medical Center, 982035 Nebraska Medical Center, Omaha, NE 68198-2035, USA.

ABSTRACT

Background: In order to improve the targeting capability and trajectory planning and provide a more secure probe-holding system, a simple method to use a stereotactic frame as an instrument holder for the frameless stereotactic system was devised.

Methods: A modified stereotactic frame and BrainLab vector vision neuronavigation sys¬tem were used together. The patient was placed in the stereotactic head-holder to which a reference array of the neuronavigation system was attached. The pointer of the frameless system was placed in the probe-holder of the frame. An offset in distances was kept between the radius of the arch of the frame and the tip of the pointer so that the pointer was always outside the head during navigation. The offset correction was made on the BrainLab monitor so that the center of the arc of the frame was at the tip of the probe line on the monitor. Then, using the frame's coordinate adjuster system, the center of the arc was positioned on the target. This method was used to insert depth electrodes (seven procedures) and gain access to the temporal horn (three procedures).

Results: Post-operative scans showed that the accuracy was within 2.5 mm in all three planes for depth electrode placement, and easy access to the temporal horn was obtained in two other patients.

Conclusion: This is a simple method to use a stereotactic frame to improve coordinate and trajectory adjustments and provides a better method to stabilize the pointer and the probe-holder during frameless stereotactic procedures.

No MeSH data available.


(Y = yoke; P = probe-holder; RA = reference array; PL = pivot-line; C = center of the arc; P = pivot; CC = c-clamp; CP = coordinate platform; H = head holder; BP = base plate). The lines converging from the yoke to the center of the arc represent the trajectories of the holes in the horizontal arm of the yoke
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Figure 0001: (Y = yoke; P = probe-holder; RA = reference array; PL = pivot-line; C = center of the arc; P = pivot; CC = c-clamp; CP = coordinate platform; H = head holder; BP = base plate). The lines converging from the yoke to the center of the arc represent the trajectories of the holes in the horizontal arm of the yoke

Mentions: The stereotactic frame is a modified Patil system[13] that was custom made at our facility. The system consists [Figure 1] of a base plate to which the head-holder (with a three-point fixation system) is attached. On one side of the base plate is a coordinate platform that carries the X-Y-Z rack and pinion type of coordinate adjuster. A single armed yoke is attached to the coordinate platform by means of a pivot. The horizontal arm of the yoke has 13 holes through its vertical thickness, which serve to hold the probe holder. The middle hole is at 90 degrees to the horizontal surface of the yoke. The center of the arc of the system is at a point where the pivot-line (a line perpendicular to the center of the pivot) intersects a perpendicular line through the center of the middle hole. All other holes are placed on either side of the middle hole at 5-degree increments (up to 30 degrees) in relationship to the center of arc. The diameter of the holes is equal to the outer diameter of a 12-gauge needle. The radius of the arc of the frame as measured from the top surface of the yoke is 15.5 cm. Because the top surface of the yoke is flat, this distance is true only for the middle hole. The other holes have a slightly greater distance. These distances are pre-calculated for each hole and correction is made for it during the procedure. The system also has a probe-holder with an inner diameter equal to the outer diameter of a 14-gauge probe that can snugly fit into the holes.


A modified stereotactic frame as an instrument holder for frameless stereotaxis: Technical note.

Patil AA - Surg Neurol Int (2010)

(Y = yoke; P = probe-holder; RA = reference array; PL = pivot-line; C = center of the arc; P = pivot; CC = c-clamp; CP = coordinate platform; H = head holder; BP = base plate). The lines converging from the yoke to the center of the arc represent the trajectories of the holes in the horizontal arm of the yoke
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2958333&req=5

Figure 0001: (Y = yoke; P = probe-holder; RA = reference array; PL = pivot-line; C = center of the arc; P = pivot; CC = c-clamp; CP = coordinate platform; H = head holder; BP = base plate). The lines converging from the yoke to the center of the arc represent the trajectories of the holes in the horizontal arm of the yoke
Mentions: The stereotactic frame is a modified Patil system[13] that was custom made at our facility. The system consists [Figure 1] of a base plate to which the head-holder (with a three-point fixation system) is attached. On one side of the base plate is a coordinate platform that carries the X-Y-Z rack and pinion type of coordinate adjuster. A single armed yoke is attached to the coordinate platform by means of a pivot. The horizontal arm of the yoke has 13 holes through its vertical thickness, which serve to hold the probe holder. The middle hole is at 90 degrees to the horizontal surface of the yoke. The center of the arc of the system is at a point where the pivot-line (a line perpendicular to the center of the pivot) intersects a perpendicular line through the center of the middle hole. All other holes are placed on either side of the middle hole at 5-degree increments (up to 30 degrees) in relationship to the center of arc. The diameter of the holes is equal to the outer diameter of a 12-gauge needle. The radius of the arc of the frame as measured from the top surface of the yoke is 15.5 cm. Because the top surface of the yoke is flat, this distance is true only for the middle hole. The other holes have a slightly greater distance. These distances are pre-calculated for each hole and correction is made for it during the procedure. The system also has a probe-holder with an inner diameter equal to the outer diameter of a 14-gauge probe that can snugly fit into the holes.

Bottom Line: This method was used to insert depth electrodes (seven procedures) and gain access to the temporal horn (three procedures).Post-operative scans showed that the accuracy was within 2.5 mm in all three planes for depth electrode placement, and easy access to the temporal horn was obtained in two other patients.This is a simple method to use a stereotactic frame to improve coordinate and trajectory adjustments and provides a better method to stabilize the pointer and the probe-holder during frameless stereotactic procedures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Neurosurgery, University of Nebraska Medical Center, 982035 Nebraska Medical Center, Omaha, NE 68198-2035, USA.

ABSTRACT

Background: In order to improve the targeting capability and trajectory planning and provide a more secure probe-holding system, a simple method to use a stereotactic frame as an instrument holder for the frameless stereotactic system was devised.

Methods: A modified stereotactic frame and BrainLab vector vision neuronavigation sys¬tem were used together. The patient was placed in the stereotactic head-holder to which a reference array of the neuronavigation system was attached. The pointer of the frameless system was placed in the probe-holder of the frame. An offset in distances was kept between the radius of the arch of the frame and the tip of the pointer so that the pointer was always outside the head during navigation. The offset correction was made on the BrainLab monitor so that the center of the arc of the frame was at the tip of the probe line on the monitor. Then, using the frame's coordinate adjuster system, the center of the arc was positioned on the target. This method was used to insert depth electrodes (seven procedures) and gain access to the temporal horn (three procedures).

Results: Post-operative scans showed that the accuracy was within 2.5 mm in all three planes for depth electrode placement, and easy access to the temporal horn was obtained in two other patients.

Conclusion: This is a simple method to use a stereotactic frame to improve coordinate and trajectory adjustments and provides a better method to stabilize the pointer and the probe-holder during frameless stereotactic procedures.

No MeSH data available.