title: Preliminary application of a multi-level 3D printing drill guide template for pedicle screw placement in severe and rigid scoliosis.
abstract: Accurate implantation of pedicle screw in spinal deformity correction surgeries is always challenging. We have developed a method of pedicle screw placement in severe and rigid scoliosis with a multi-level 3D printing drill guide template.
  
  
  
  From November 2011 to March 2015, ten patients (4 males and 6 females) with severe and rigid scoliosis (Cobb angle >70° and flexibility <30%)were included. Multi-level template was designed and manufactured according to the part (two or three levels) of the most severe deformity. The drill template was then placed on the corresponding vertebral surface. Then, pedicle screws were carefully inserted along the trajectories. The other screws were placed in free hand. After surgery, the positions of the pedicle screws were evaluated by CT scan and graded for validation.
  
  
  
  48 screws were implanted using templates, other 104 screws in free hand, and the accuracies were 93.8 and 78.8%, respectively, with significant difference. The deformity correction ratio was 67.1 and 41.2% in coronal and sagittal plane post-operatively, respectively. The average operation time was 234.0 ± 34.1 min, and average blood loss was 557 ± 67.4 ml.
  
  
  
  With the application of multi-level template, the incidence of cortex perforation in severe and rigid scoliosis decreased and this technology is, therefore, potentially applicable in clinical practice.
authors.affiliation: The Hospital of Shunyi District Beijing, Beijing, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Orthopedics, Beijing Ditan Hospital, Capital Medical University, No. 8, Jingshun East Street, Chaoyang District, Beijing, 100015, China. drlklfbd@sina.com.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Orthopedics, Beijing Ditan Hospital, Capital Medical University, No. 8, Jingshun East Street, Chaoyang District, Beijing, 100015, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Orthopedics, Beijing Ditan Hospital, Capital Medical University, No. 8, Jingshun East Street, Chaoyang District, Beijing, 100015, China.
authors.forename: Changsong
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Orthopedics, Beijing Ditan Hospital, Capital Medical University, No. 8, Jingshun East Street, Chaoyang District, Beijing, 100015, China.
authors.forename: Xuemin
authors.initials: X
authors.lastname: Quan
authors.affiliation: Department of Orthopedics, Beijing Ditan Hospital, Capital Medical University, No. 8, Jingshun East Street, Chaoyang District, Beijing, 100015, China.
authors.forename: Rugang
authors.initials: R
authors.lastname: Zhao
authors.affiliation: Third military Medical University, Chongqing, China.
authors.forename: Zongfeng
authors.initials: Z
authors.lastname: Chen
authors.affiliation: College of Electromechanical Engineering, Beijing University of Technology, Beijing, China.
authors.forename: Yansheng
authors.initials: Y
authors.lastname: Li
mesh_terms: D000293:Adolescent; D016063:Blood Loss, Surgical; D005260:Female; D006801:Humans; D008297:Male; D061646:Operative Time; D065289:Pedicle Screws; D066330:Printing, Three-Dimensional; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000601:surgery; D012720:Severity of Illness Index; D025321:Surgery, Computer-Assisted; D055815:Young Adult
keywords: 3D printing; Computer-assisted surgery; Scoliosis; Surgical template