Ken Ishii1, Yasuhito Kaneko2, Haruki Funao3, Shinichi Ishihara4, Akira Shinohara5, Kazuo Nakanishi6, Tomohiro Hikata4, Nobuyuki Fujita4, Akio Iwanami4, Naobumi Hosogane4, Kota Watanabe7, Takeo Nagura7, Masaya Nakamura7, Yoshiaki Toyama7, Morio Matsumoto7. 1. Keio University, Tokyo, Japan Society for Minimally Invasive Spine Stabilization, Nagoya, Aichi, Japan keni8888@z7.keio.jp. 2. Society for Minimally Invasive Spine Stabilization, Nagoya, Aichi, Japan Kawasaki Municipal Kawasaki Hospital, Kanagawa, Japan. 3. Society for Minimally Invasive Spine Stabilization, Nagoya, Aichi, Japan Nerima General Hospital, Tokyo, Japan Johns Hopkins University, Baltimore, MD, USA. 4. Keio University, Tokyo, Japan Society for Minimally Invasive Spine Stabilization, Nagoya, Aichi, Japan. 5. Society for Minimally Invasive Spine Stabilization, Nagoya, Aichi, Japan Jikei University Kashiwa Hospital, Chiba, Japan. 6. Society for Minimally Invasive Spine Stabilization, Nagoya, Aichi, Japan Kawasaki Medical School, Okayama, Japan. 7. Keio University, Tokyo, Japan.
Abstract
PURPOSE: Minimally invasive spine stabilization (MISt) procedures, including MIS-transforaminal lumbar interbody fusion (MIS-TLIF), rely on precise placement of percutaneous pedicle screws (PPS). Serious intraoperative complications associated with PPS placement include great vessel and bowel injuries due to the guide-wire's anterior migration and penetration through the anterior aspect of the vertebral body. To address this issue, we developed a novel percutaneous guide wire (S-wire) and compared the biomechanical characteristics of S-wire and conventional wire in cadaveric spines, and to evaluate the S-wire's efficacy and safety in a clinical trial. METHODS: The S-wire is hollow, with braided wires extending at one tip. We compared the push-out and penetration forces of the S-wire and conventional wire in fresh cadaveric lumbar spines, from L1 to L5. RESULTS: Push-out forces caused the braided tip of the S-wire to bend or spread, and thus to resist anterior migration. The mean push-out forces for the S-wire and conventional wire were 15.5 ± 1.9 and 5.7 ± 0.8 N, respectively (P < .0001); the mean penetration forces were 69.1 ± 4.2 and 37.1± 4.8 N, respectively (P < .0005). There was no wire breakage or anterior-wall penetration in a clinical trial of 922 S-wires; interestingly, the pull-out force increased in 780 (84.6%) S-wires after placement. CONCLUSIONS: The mean push-out and penetration forces for the S-wire were approximately 3 and 2 times greater than those of conventional wire, respectively. The S-wire effectively prevented guide-wire anterior migration and penetration of the anterior vertebral-body wall. The S-wire device should effectively improve the safety of MISt procedures, including MIS-TLIF and percutaneous kyphoplasty in selected patient with osteoporosis.
PURPOSE: Minimally invasive spine stabilization (MISt) procedures, including MIS-transforaminal lumbar interbody fusion (MIS-TLIF), rely on precise placement of percutaneous pedicle screws (PPS). Serious intraoperative complications associated with PPS placement include great vessel and bowel injuries due to the guide-wire's anterior migration and penetration through the anterior aspect of the vertebral body. To address this issue, we developed a novel percutaneous guide wire (S-wire) and compared the biomechanical characteristics of S-wire and conventional wire in cadaveric spines, and to evaluate the S-wire's efficacy and safety in a clinical trial. METHODS: The S-wire is hollow, with braided wires extending at one tip. We compared the push-out and penetration forces of the S-wire and conventional wire in fresh cadaveric lumbar spines, from L1 to L5. RESULTS: Push-out forces caused the braided tip of the S-wire to bend or spread, and thus to resist anterior migration. The mean push-out forces for the S-wire and conventional wire were 15.5 ± 1.9 and 5.7 ± 0.8 N, respectively (P < .0001); the mean penetration forces were 69.1 ± 4.2 and 37.1± 4.8 N, respectively (P < .0005). There was no wire breakage or anterior-wall penetration in a clinical trial of 922 S-wires; interestingly, the pull-out force increased in 780 (84.6%) S-wires after placement. CONCLUSIONS: The mean push-out and penetration forces for the S-wire were approximately 3 and 2 times greater than those of conventional wire, respectively. The S-wire effectively prevented guide-wire anterior migration and penetration of the anterior vertebral-body wall. The S-wire device should effectively improve the safety of MISt procedures, including MIS-TLIF and percutaneous kyphoplasty in selected patient with osteoporosis.