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P34. Spinal instrumentation surgery with intraoperative three-dimensional fluoroscopy and CT-based navigation system
126S
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S
CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.248
P34. Spinal instrumentation surgery with intraoperative three-dimensional fluoroscopy and CT-based navigation system Yasuo Ito, Nobuo Kai, Yasuhiro Hasegawa; Kobe Red Cros Hospital, Kobe, Hyogo, Japan BACKGROUND CONTEXT: CT-based surgical navigation made it possible to achieve a link between preoperative three-dimensional (3D) data and the intra-operative instrument position. However, the use of traditional 3D navigation techniques requires a so-called registration process, performed manually by approaching landmarks on the patient with the instrument. Changes in the anatomy cannot be detected intra-operatively, therefore applications for CT-based navigation are limited. PURPOSE: The mobile SIREMOBIL Iso-C 3D fluoroscopy (Iso-C C-arm) is one of the first devices that permits the intra-operative 3D representation of bone structures, accurately correlates 3D images with the patient’s intra-operative anatomy, and updates image data to support navigation. The authors prospectively examined data from the initial 50 patients with the Iso-C C-arm and investigated the accuracy the pedicle screw placement by use of Iso-C C-arm and CT-based navigation system. STUDY DESIGN/SETTING: Prospectively, we investigated the accuracy of pedicle screws placement with the Iso-C C-arm and CT-based navigation system. PATIENT SAMPLE: A total of 50 patients who had undergone intraoperative navigation using Iso-C C-arm were included in a prospective study from July 2004 until December 2004. Spinal procedures were performed to treat a wide range of degenerative, traumatic, and neoplastic disorders at all levels of the spine. A patient group from the period between April 2004 and June 2004 served as comparison group. During this period, 26 patients underwent surgery with CT-based navigation. OUTCOME MEASURES: Comparisons and investigations about the accuracy of pedicle screws placement between the patients group with IsoC C-arm and the control group with only CT-based navigation system. METHODS: Intra-operatively, an Iso-C C-arm was used to obtain CT images of the spines of the 50 patients. The clinical workflow in registrationfree 3D navigation is described as follows: A reference array is positioned on the spinous process of patients. The navigation system camera is set up and Iso-C C-arm is moved to start position. The automatic 3D scan is performed. After the scan, the 3D images data coordinates are transferred directly to the navigation system. The C-arm can be removed and navigation surgery can begin. The pedicle screws position was postoperatively evaluated with thin-cut CT scanning to determine the accuracy of screw placement. RESULTS: There is no neurovascular injury during operation. A total of 322 of 325 screws were accurately placed. Only three screws violated the margin of the thoracic pedicle wall. The cortical violation was less than 2 mm in two screws as measured on postoperative CT scans. The third case (screw) showed lateral violation of the pedicle, but the trajectory of the screw showed the course with “in out in technique”. On the other hand, five of 156 screws (3.2%) violated the margin of the pedicle wall in the control group. CONCLUSIONS: Registration-free navigation surgery with Iso-C C-arm was successfully used. As compared with the CT-based navigation only, the lower rate of incorrect placements was achieved during the placement of pedicle screws on the spine with Iso-C C-arm navigation surgery. DISCLOSURES: FDA device/drug: Siremobil Iso-C3D fluoroscope. Status: Approved for this indication. FDA device/drug: StealthStation image guided surgery workstation. Status: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.249
P35. C12 Transarticular screw fixation in high-riding vertebral artery: suggestion of new trajectory Chun Kee Chung, MD1*, Tae-Ahn Jahng1, Hong Jun Park2; 1Seoul National University Hospital, Seoul, South Korea; 2Seoul National University, Seoul, South Korea BACKGROUND CONTEXT: C1-2 transarticular screw fixation is a method of rigid internal screw fixation for posterior C1-2 fusion. A significant drawback of this procedure is a potential risk of vertebral artery injury, especially with a high-riding vertebral artery. PURPOSE: In this study, using 3D CT reconstruction images we propose a relatively safe trajectory in cases of high-riding vertebral artery. STUDY DESIGN/SETTING: From January 2003 to November 2004, 9 consecutive patients having C1-2 transarticular screw fixation and 21 patient with other cervical spinal disorder were analyzed. PATIENT SAMPLE: Male to female ratio was 17:13 (3:6 in C1-2 screw fixation). Age ranged from 26 to 81 (mean, 52 years). OUTCOME MEASURES: A CT scan with 1.5-mm slice interval including C1 and C2 with GE Lightspeed Ultra CT was performed for each patient. CT 3D reconstruction images were obtained with V-works 4.0 software (CyberMed, Bundang, Korea). METHODS: High-riding vertebral artery was defined when the isthmus height was less than 5 mm, or the internal height of the lateral mass (measured from the roof of the vertebral artery groove to the surface of the superior facet) was less than 2 mm. RESULTS: Of 30 subjects, 8 had high-riding vertebral artery at least unilaterally. Five had bilateral high-riding ones. In 9 patients having C12 screw fixation, 3 had high-riding vertebral artery. Of these 3, one vertebral artery injury occurred, resulting in endovascular trapping of the injured artery. In two other patients, screw trajectory was moved superiorly and medially like pedicle screwing. In 13 control sides having high-riding verterbral artery, superior and medial trajectory revealed 1.5⫾0.6 mm of distance to the vertebral artery from the edge of an ideally placed screw (not including the patient in whom screw trajectory was felt impossible), which enabled safe insertion of transarticular screwing. In cases of 6 transarticular screwed sides, superior and medial trajectory revealed 2.2⫾0.7 mm. CONCLUSIONS: It is possible to insert tranarticular screws safely using superior and medial trajectory, especially in cases having high-riding vertebral arteries. It is helpful to analyze and simulate the trajectory of screw with CT 3D reconstruction before surgery. DISCLOSURES: FDA device/drug: Transarticular screw. Status: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.250
P36. Long-term retrospective study of first generation Wallis implant Paul C. McAfee, MD; Towson, MD, USA BACKGROUND CONTEXT: In 1986, Pr. Se´ne´gas in Bordeaux France introduced a novel treatment of lumbar degenerative disc disease, between early stages when conservative treatment is indicated and advanced stages calling for fusion. This system was secured without pedicle screw fixation. The implant consisted in one or more interspinous spacers (to limit extension) attached by a tension band around the corresponding spinous processes (to restrict flexion). The Bordeaux spinal surgery unit tested the device as a means of stabilizing lumbar segments after decompression of canal stenosis by partial laminectomy and flavectomy. They also used this system after massive or recurrent disc herniation, and in primary herniated discs at L4-L5 in patients with L5 sacralization, in all cases as a means of preventing subsequent low-back pain due to loss of rigidity in these segments. PURPOSE: The study was carried out to determine the long-term actuarial survival rate of the implant in the patients who underwent the procedure at the spinal unit of Bordeaux University Hospital between 1987 and 199.
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S
CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.248
P34. Spinal instrumentation surgery with intraoperative three-dimensional fluoroscopy and CT-based navigation system Yasuo Ito, Nobuo Kai, Yasuhiro Hasegawa; Kobe Red Cros Hospital, Kobe, Hyogo, Japan BACKGROUND CONTEXT: CT-based surgical navigation made it possible to achieve a link between preoperative three-dimensional (3D) data and the intra-operative instrument position. However, the use of traditional 3D navigation techniques requires a so-called registration process, performed manually by approaching landmarks on the patient with the instrument. Changes in the anatomy cannot be detected intra-operatively, therefore applications for CT-based navigation are limited. PURPOSE: The mobile SIREMOBIL Iso-C 3D fluoroscopy (Iso-C C-arm) is one of the first devices that permits the intra-operative 3D representation of bone structures, accurately correlates 3D images with the patient’s intra-operative anatomy, and updates image data to support navigation. The authors prospectively examined data from the initial 50 patients with the Iso-C C-arm and investigated the accuracy the pedicle screw placement by use of Iso-C C-arm and CT-based navigation system. STUDY DESIGN/SETTING: Prospectively, we investigated the accuracy of pedicle screws placement with the Iso-C C-arm and CT-based navigation system. PATIENT SAMPLE: A total of 50 patients who had undergone intraoperative navigation using Iso-C C-arm were included in a prospective study from July 2004 until December 2004. Spinal procedures were performed to treat a wide range of degenerative, traumatic, and neoplastic disorders at all levels of the spine. A patient group from the period between April 2004 and June 2004 served as comparison group. During this period, 26 patients underwent surgery with CT-based navigation. OUTCOME MEASURES: Comparisons and investigations about the accuracy of pedicle screws placement between the patients group with IsoC C-arm and the control group with only CT-based navigation system. METHODS: Intra-operatively, an Iso-C C-arm was used to obtain CT images of the spines of the 50 patients. The clinical workflow in registrationfree 3D navigation is described as follows: A reference array is positioned on the spinous process of patients. The navigation system camera is set up and Iso-C C-arm is moved to start position. The automatic 3D scan is performed. After the scan, the 3D images data coordinates are transferred directly to the navigation system. The C-arm can be removed and navigation surgery can begin. The pedicle screws position was postoperatively evaluated with thin-cut CT scanning to determine the accuracy of screw placement. RESULTS: There is no neurovascular injury during operation. A total of 322 of 325 screws were accurately placed. Only three screws violated the margin of the thoracic pedicle wall. The cortical violation was less than 2 mm in two screws as measured on postoperative CT scans. The third case (screw) showed lateral violation of the pedicle, but the trajectory of the screw showed the course with “in out in technique”. On the other hand, five of 156 screws (3.2%) violated the margin of the pedicle wall in the control group. CONCLUSIONS: Registration-free navigation surgery with Iso-C C-arm was successfully used. As compared with the CT-based navigation only, the lower rate of incorrect placements was achieved during the placement of pedicle screws on the spine with Iso-C C-arm navigation surgery. DISCLOSURES: FDA device/drug: Siremobil Iso-C3D fluoroscope. Status: Approved for this indication. FDA device/drug: StealthStation image guided surgery workstation. Status: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.249
P35. C12 Transarticular screw fixation in high-riding vertebral artery: suggestion of new trajectory Chun Kee Chung, MD1*, Tae-Ahn Jahng1, Hong Jun Park2; 1Seoul National University Hospital, Seoul, South Korea; 2Seoul National University, Seoul, South Korea BACKGROUND CONTEXT: C1-2 transarticular screw fixation is a method of rigid internal screw fixation for posterior C1-2 fusion. A significant drawback of this procedure is a potential risk of vertebral artery injury, especially with a high-riding vertebral artery. PURPOSE: In this study, using 3D CT reconstruction images we propose a relatively safe trajectory in cases of high-riding vertebral artery. STUDY DESIGN/SETTING: From January 2003 to November 2004, 9 consecutive patients having C1-2 transarticular screw fixation and 21 patient with other cervical spinal disorder were analyzed. PATIENT SAMPLE: Male to female ratio was 17:13 (3:6 in C1-2 screw fixation). Age ranged from 26 to 81 (mean, 52 years). OUTCOME MEASURES: A CT scan with 1.5-mm slice interval including C1 and C2 with GE Lightspeed Ultra CT was performed for each patient. CT 3D reconstruction images were obtained with V-works 4.0 software (CyberMed, Bundang, Korea). METHODS: High-riding vertebral artery was defined when the isthmus height was less than 5 mm, or the internal height of the lateral mass (measured from the roof of the vertebral artery groove to the surface of the superior facet) was less than 2 mm. RESULTS: Of 30 subjects, 8 had high-riding vertebral artery at least unilaterally. Five had bilateral high-riding ones. In 9 patients having C12 screw fixation, 3 had high-riding vertebral artery. Of these 3, one vertebral artery injury occurred, resulting in endovascular trapping of the injured artery. In two other patients, screw trajectory was moved superiorly and medially like pedicle screwing. In 13 control sides having high-riding verterbral artery, superior and medial trajectory revealed 1.5⫾0.6 mm of distance to the vertebral artery from the edge of an ideally placed screw (not including the patient in whom screw trajectory was felt impossible), which enabled safe insertion of transarticular screwing. In cases of 6 transarticular screwed sides, superior and medial trajectory revealed 2.2⫾0.7 mm. CONCLUSIONS: It is possible to insert tranarticular screws safely using superior and medial trajectory, especially in cases having high-riding vertebral arteries. It is helpful to analyze and simulate the trajectory of screw with CT 3D reconstruction before surgery. DISCLOSURES: FDA device/drug: Transarticular screw. Status: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.250
P36. Long-term retrospective study of first generation Wallis implant Paul C. McAfee, MD; Towson, MD, USA BACKGROUND CONTEXT: In 1986, Pr. Se´ne´gas in Bordeaux France introduced a novel treatment of lumbar degenerative disc disease, between early stages when conservative treatment is indicated and advanced stages calling for fusion. This system was secured without pedicle screw fixation. The implant consisted in one or more interspinous spacers (to limit extension) attached by a tension band around the corresponding spinous processes (to restrict flexion). The Bordeaux spinal surgery unit tested the device as a means of stabilizing lumbar segments after decompression of canal stenosis by partial laminectomy and flavectomy. They also used this system after massive or recurrent disc herniation, and in primary herniated discs at L4-L5 in patients with L5 sacralization, in all cases as a means of preventing subsequent low-back pain due to loss of rigidity in these segments. PURPOSE: The study was carried out to determine the long-term actuarial survival rate of the implant in the patients who underwent the procedure at the spinal unit of Bordeaux University Hospital between 1987 and 199.