Case Studies

Case Study 1

T12-L3 Fixation Across L2 Burst Fracture

Hospital: Vail Valley Medical Center, Colorado
Surgeon: Dr. Don Corenman
Date:  February 2007
Admitting Diagnosis: Progressive Kyphotic Deformity
History: 27-year-old male with L2 burst fracture from ski-jumping accident.

Case Study: T12-L3 Fixation Across L2 Burst Fracture (PDF, 268 KB)

Comment

Picture of room setup showing display and navigation of the screw with Awl/Probe/Tap instrument

The patient's anatomy is somewhat mobile and misaligned with this type of vertebral fracture and reduces the natural lordosis of the spine. As a result, preoperative imaging (CT) is of limited use for navigation, and 2D imaging is limiting in that it does not provide valuable axial views. The O-arm^® System with StealthStation^® System navigation allowed the surgeon to visualize his pedicle preparation and screw placement at all affected levels while utilizing Medtronic Spinal and Biologics instrumentation. Additionally, the O-arm System in combination with the StealthStation System may reduce surgeon and staff radiation exposure.

After the pedicle screws and rods were placed, the surgeon was able to employ the O-arm System to determine the amount of correction made to the fragmented vertebral body and resultant lordotic alignment. In this instance, the surgeon discovered that bone fragments did not reduce back to normal position and subsequently decided to perform a more aggressive correction. Utilizing the O-arm System in this way avoided a second surgery and additional hospital and patient costs, while improving patient outcome. Additionally, it allowed the surgeon to provide a superior level of care to this patient, by assessing his fracture reduction and determining whether or not fragments remained in the canal.

"This technology is amazing. It is the standard of care on difficult cases like this one."
— Dr. Don Corenman

Results of this study are specific to this case and do not necessarily reflect the outcome for all similar surgeries.

Snapshot image of the O-arm System display showing the axial, coronal, and sagittal views of the burst fracture

Snapshot image of O-arm System display showing intraoperative postoperative confirmation of the screw placement

Left - Snapshot from StealthStation^® System display showing navigation of the Tactile Probe prior to screw placement.

Right - Snapshot from StealthStation^® System display showing navigation of a spinal screw with our Awl/Probe/Tap Instrument.

Case Study 2

Screw Placement in Anterior Column of the Ilium

Hospital: Medical Center of the Rockies
Surgeon: Dr. Mark McFerran
Date: February 2007
Patient History:  27-year-old male with fractured pelvis from auto impact.

Screw Place in Anterior Column of the Illium (PDF, 236 KB)

StealthStation System snapshot of navigation with the Short Universal Drill Guide and trajectory prior to guidewire placement

Snapshot from the O-arm System display showing standard 2D fluoroscopic image to confirm hardware placement

 

 

Snapshot from the O-arm System display showing 3D intraoperative post-completion screw placement

Comment

During screw placement procedures, a surgeon may utilize two C-arms or a single C-arm that is positioned from inlet to outlet views to visualize the entry point location. This particular type of screw is placed in a deep area of the pelvis that is difficult to access.

The O-arm^® System was positioned around the patient to acquire a 3D image data set of the anatomy with the patient in the surgical position. The 3D image data set was instantly transferred to the StealthStation^® System for instrument navigation. The StealthStation System allowed the surgeon to visualize the anterior column of the ilium and the surgical instruments from the skin level down through the complete trajectory of screw placement. This may reduce the chance of a misplaced screw – potentially improving accuracy, surgeon confidence, and patient outcomes. The ability to utilize the O-arm System to confirm placement of the screws intraoperatively is of tremendous value to the patient, the hospital, and surgeon by potentially avoiding the need for revision surgeries.

"The O-arm System makes difficult procedures easier."
— Dr. McFerran

Results of this study are specific to this case and do not necessarily reflect the outcome for all similar surgeries.

Case Study 3

Detail - Figures 1 & 2: Exposing bony surfaces quickly with probe; navigating thoracic screw placement

Detail - Figure 3: Post thoracic screw implant O-arm System image, confirming the quality of placement

Detail - Figures 4 & 5: Insertion of ipsilateral screw in lumbar spine, down screw hole form previous surger, attaining bicortical purchase

Results

While the case was planned for 14 hours, it lasted approximately 8 hours, including plastic surgical reconstruction. Six months following surgery, the patient has minimal pain and is doing well with a stable construct, despite a motor vehicle accident at 5 months post-op.

Results of this study are specific to this case and do not necessarily reflect the outcome for all similar surgeries.

Thoracolumbar Revision

Hospital:  HCA/Menorah Medical Center, Kansas City, MO
Surgeon: William S. Rosenberg, M.D., Midwest Neurosurgery Associates
Admitting Diagnosis: Progressive Kyphotic Deformity
Date: November 2008

Thoracolumbar Revision (PDF, 4.6 MB)

Presentation
The patient is a 56 year-old woman with a history of breast cancer and cord compression, prior thoracic laminectomy with progressive kyphotic deformity requiring anterior and posterior reconstructions, radiation and wound infection. Corpectomy at T11-12 has kyphosed but is fused T-11 to L1. She has virtually no soft tissue coverage over laminectomy defect.

Procedure

In order to stabilize the patient, it is required to bridge the fusion mass with rods and screws, 3 levels above and 3 levels below the fusion mass. This is a long construct which needs to be placed through a thick layer (~1 to 2 inches) of scar tissue, following multiple surgeries and radiation therapy. OR setup was standard for a posterior approach, utilizing a Jackson table. The O-arm^® System was draped, brought into the field and kept at the foot of the bed for easy access to repeat dataset acquisition.

After sterile preparation, a small incision was made and the reference arc was clamped to T5, with the navigation camera at the head of the patient. An O-arm System dataset was obtained and navigation enabled. A navigated pointer was used to efficiently expose the thoracic spine through the scar tissue, expeditiously exposing the bony surfaces while confidently avoiding injury to the dura or spinal cord, as well as to plan the screw trajectory through the thoracic pedicles.

A twist drill was set-up for navigation with the SureTrak^® tracking array, and the pedicles were prepared with the twist drill. Screws were placed with navigated taps and screwdriver. After the thoracic screws were implanted, an O-arm System dataset (non-navigated) was obtained to ensure quality screw placement.

The reference arc was then moved to L5 and the navigation camera to the foot of the patient. An O-arm System dataset was obtained and navigation enabled for the lumbar portion of the procedure, repeating the steps described in the thoracic portion above. After the lumbar screws were implanted, an O-arm System dataset (non-navigated) was obtained to ensure quality screw placement. The surgeon was able to place screws safely and efficiently in both ipsilateral and contralateral pedicles. With the use of the O-arm System images and navigation, it is possible to perform the entire procedure efficiently from one side.