title: S2 alar iliac screw placement under robotic guidance for adult spinal deformity patients: technical note.
abstract: S2 alar-iliac (S2AI) screws are generally placed using an open approach, but have recently been shown to be implantable using a minimally invasive approach. Nevertheless, optimal screw positioning, even when supported by fluoroscopic guidance, is challenging in the complex anatomy of the sacral-pelvic area. This work presents our novel technique of S2AI sacropelvic fixation procedures performed with robotic guidance.
  
  
  
  This was a single-center, retrospective, mini case-series of adult spinal deformity patients in need of sacropelvic fixation as part of a longer thoraco-lumbar fusion. The surgeon drilled a pilot hole through a robotic guide and then inserted a K-wire. A Jamshidi needle was placed over the K-wire and used to advance the pilot hole anterolaterally.
  
  
  
  Medical charts of four 60-70 year-old patients, who underwent robotic-guided insertion of S2AI screws in a minimally invasive approach were reviewed. Follow-up ranged between 10 and 13 months. Post-operative CTs and X-rays showed all eight trajectories were fully within the bone and accurately placed. Average surgery time per patient was 13 min with 5.3 s of fluoroscopy per screw. No intra- or post-operative complications occurred.
  
  
  
  Robotic-guidance with a Jamshidi needle technique was a safe and effective means for implanting S2AI screws in a minimally invasive approach.
authors.affiliation: Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 82 Gumi-ro, 173 Beon-Gil, Bundang, Seongnam, 463-707, Gyeonggi, Republic of Korea. hyunsj@snu.ac.kr.
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Hyun
authors.affiliation: Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 82 Gumi-ro, 173 Beon-Gil, Bundang, Seongnam, 463-707, Gyeonggi, Republic of Korea.
authors.forename: Ki-Jeong
authors.initials: KJ
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 82 Gumi-ro, 173 Beon-Gil, Bundang, Seongnam, 463-707, Gyeonggi, Republic of Korea.
authors.forename: Tae-Ahn
authors.initials: TA
authors.lastname: Jahng
mesh_terms: D000368:Aged; D001863:Bone Screws; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007085:Ilium / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D065287:Robotic Surgical Procedures; D012447:Sacrum / Q000601:surgery*; D013121:Spinal Curvatures / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D016896:Treatment Outcome
keywords: Adult spinal deformity; Minimally invasive approach; Robotic-guidance; S2 alar-iliac screw