Miniature robotic guidance for spine surgery

Instrumented spinal fusion surgery is increasingly performed in the treatment of degenerative disorders, Spondylolisthesis, deformity, trauma and tumors affecting the spine (Davis, 1994; Katz, 1995). In-vitro and In-vivo studies using the free hand or fluoroscopically assisted techniques documented breaching of the pedicle in 3-55% (Amiot et al., 2000; Belmont et al., 2001; Belmont et al., 2002; Boachie-Adjei et al., 2000; Carbone et al., 2003; Castro et al., 1996; Esses et al., 1993; Farber et al., 1995; Gertzbein & Robbins, 1990; Laine et al., 1997a; Laine et al., 1997b; Laine et al., 2000; Liljenqvist et al., 1997; Lonstein et al., 1999; Odgers et al., 1996; Schulze et al., 1998; Suk et al., 1995; Vaccaro et al., 1995a; Vaccaro et al. 1995b; Weinstein et al., 1998; Xu et al., 1998) Clinically significant screw misplacements however occur in 0-7% (Amiot et al. 2000; Belmont et al.2002; Belmont et al. 2001; Boachie-Adjei et al. 2000; Carbone et al. 2003; Castro et al. 1996; Esses et al. 1993; Farber et al. 1995; Gertzbein & Robbins, 1990; Laine et al. 2000; Laine et al. 1997a; Liljenqvist et al. 1997; Lonstein et al. 1999; Odgers et al. 1996; Schulze et al. 1998). Neuro-monitoring, neuro-stimulation, and computed assisted navigation systems reduce the incidence of screw misplacement, however none of them has gained significant popularity in spine surgery, mainly due to logistical and cost-effectiveness issues such as the need for dynamic referencing and a line-of sight, extra staff, expensive tools and cumbersome procedures, longer operation time and the high cost of the capital equipment (Berlermann et al. 1997; Bolger & Wigfield, 2000; Carl et al. 1997; Choi et al. 2000; Digioia et al. 1998; Ebmeier et al. 2003; Foley & Smith, 1996; Girardi et al. 1999; Glossop et al. 1996; Kalfas et al. 1995; Kim et al. 2001; Laine et al. 1997b; Merloz et al. 1998; Mirza et al. 2003; Rampersaud et al. 2001; Rampersaud and Foley, 2000; Raynor et al. 2002; Reidy et al. 2001; Schlenzka et al. 2000; Schwarzenbach et al. 1997; Simon and Lavallee, 1998; Welch et al. 1997). Surgical robots have emerged during the 1990's and offer distinct added value in terms of accuracy and minimally-invasiveness of the surgical procedure. However, current systems are extremely expensive and large in size, and typically require immobilization of the patient (Taylor & Stoianovici, 2003). The SpineAssist® (Shoham et al. 2003) (Mazor Surgical Technologies, Caesarea, Israel) is a bone-mounted miniature robotic guidance system, clinically and experimentally validated for spinal surgery (Barzilay et al. 2006, Lieberamn et al 2006; Togawa et al. 2007). It facilitates image-based semi-active guidance for providing high accuracy in the positioning of surgical tools and implantable devices such as Pedicle O pe n A cc es s D at ab as e w w w .ite ch on lin e. co m