scholarly journals Ball Tip Technique for S2AI Screw Placement in Sacropelvic Fixation: A Comparative Study with Conventional Freehand Technique

2022 ◽  
Author(s):  
Zhenhai Zhou ◽  
Cheng Tu ◽  
Honggui Yu ◽  
Jiachao Xiong ◽  
Zhiming Liu ◽  
...  
Keyword(s):  
Comparative Study ◽  
Screw Placement ◽  
Sacropelvic Fixation ◽  
Freehand Technique

The three-dimensional printed template guided technique for S2AI screw placement and a comparison with freehand technique

2020 ◽  
Author(s):  
Zhenhai Zhou ◽  
Zhimin Zeng ◽  
Honggui Yu ◽  
Jiachao Xiong ◽  
Zhiming Liu ◽  
...  
Keyword(s):  
Adult Spinal Deformity ◽  
Three Dimensional ◽  
Deformity Correction ◽  
Asian Population ◽  
Screw Placement ◽  
Asian Patients ◽  
Sacropelvic Fixation ◽  
Freehand Technique ◽  
Group 3 ◽  
Adult Volunteers

Abstract Background Sacropelvic fixation continues to present challenges when involved in the adult spinal deformity correction. The S2 alar iliac (S2AI) fixation is commonly used in sacropelvic fixation. Several techniques, including intraoperative navigation and freehand technique, were used for S2AI screws placement. The aim of this study is to analyze the anatomic parameters for S2AI screw trajectory in Asian population and introduce a novel technique described as three-dimensional printed template guided technique (TGT). Meanwhile, the accuracy and safety of this technique were compared with conventional freehand technique. Methods The S2AI trajectory parameters were measured in100 Asian adult volunteers. Parameters were compared between different genders. Forty-eight adult patients who underwent S2AI screw placement were reviewed, 28 patients received freehand technique and 20 patients received TGT technique. Postoperative CT was used to assess the accuracy of screw trajectory and cortex violation related complications were recorded. Results The cephalocaudal angles (CA), maximal length of screw pathway (ML), narrowest width of pathway within the iliar teardrop (NW), distance from the center of teardrop to sciatic notch(SD) and distance of the start point distal to S1 dorsal foramen(DD) showed significant gender-related difference (p<0.05). All 48 patients were placed S2AI screws bilaterally (40 screws in TGT vs 56 screws in freehand). One screw penetrated iliac cortex in TGT group but 10 screws penetrated iliac cortex in freehand group (3% vs 17.9%) (p<0.05). Conclusion Approximately 30-35° of cephalocaudal angle and 39°mediolateral angle are appropriate for S2AI screw placement in Asian patients. Either freehand or TGT technique is safe for S2AI screw placement. TGT technique is more accurate compared with conventional freehand technique. Trial registration This is a retrospective study. Key words Sacropelvic fixation, Second sacral alar iliac (S2AI) screw, three-dimensional printed template, freehand technique

scholarly journals The three-dimensional printed template guided technique for S2 alar iliac screw placement and a comparison with freehand technique

2020 ◽  
Vol 28 (3) ◽  
pp. 230949902096711
Author(s):  
Zhenhai Zhou ◽  
Zhimin Zeng ◽  
Honggui Yu ◽  
Jiachao Xiong ◽  
Zhiming Liu ◽  
...  
Keyword(s):  
Adult Spinal Deformity ◽  
Three Dimensional ◽  
Deformity Correction ◽  
Asian Population ◽  
Screw Placement ◽  
Asian Patients ◽  
Sacropelvic Fixation ◽  
Freehand Technique ◽  
Iliac Screw ◽  
Group 3

Purpose: Sacropelvic fixation continues to present challenges when involved in the adult spinal deformity correction. The S2 alar iliac (S2AI) fixation is commonly used in sacropelvic fixation. Several techniques, including intraoperative navigation and freehand technique, were used for S2AI screws placement. The aim of this study is to analyze the anatomic parameters for S2AI screw trajectory in Asian population and introduce a novel technique described as a three-dimensional printed template guided technique (TGT). Meanwhile, the accuracy and safety of this technique were compared with the conventional freehand technique. Methods: The S2AI trajectory parameters were measured in 100 Asian adult volunteers. Parameters were compared between different genders. Forty-eight adult patients who underwent S2AI screw placement were reviewed: 28 patients received freehand technique and 20 patients received TGT technique. Postoperative computed tomography was used to assess the accuracy of screw trajectory and cortex violation-related complications were recorded. Results: The cephalocaudal angles (CAs), maximal length of screw pathway, narrowest width of pathway within the iliar teardrop, distance from the center of teardrop to sciatic notch, and distance of the start point distal to S1 dorsal foramen showed significant gender-related difference ( p < 0.05). All 48 patients were placed S2AI screws bilaterally (40 screws in TGT vs. 56 screws in freehand). One screw penetrated iliac cortex in the TGT group but 10 screws penetrated iliac cortex in the freehand group (3% vs. 17.9%) ( p < 0.05). Conclusion: Approximately 30–35° of CA and 39° mediolateral angle are appropriate for S2AI screw placement in Asian patients. Either freehand or TGT technique is safe for S2AI screw placement. TGT technique is more accurate compared with the conventional freehand technique. Trial registration: This is a retrospective study.

scholarly journals Evaluation of C2 pedicle screw placement via the freehand technique by neurosurgical trainees

2018 ◽  
Vol 29 (3) ◽  
pp. 235-240 ◽  
Author(s):  
Martin H. Pham ◽  
Joshua Bakhsheshian ◽  
Patrick C. Reid ◽  
Ian A. Buchanan ◽  
Vance L. Fredrickson ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Medical Center ◽  
Pedicle Screws ◽  
Screw Placement ◽  
Pedicle Screw Placement ◽  
C2 Pedicle Screw ◽  
Canal Diameter ◽  
Screw Length ◽  
Freehand Technique ◽  
Screw Diameter

OBJECTIVEFreehand placement of C2 instrumentation is technically challenging and has a learning curve due the unique anatomy of the region. This study evaluated the accuracy of C2 pedicle screws placed via the freehand technique by neurosurgical resident trainees.METHODSThe authors retrospectively reviewed all patients treated at the LAC+USC Medical Center undergoing C2 pedicle screw placement in which the freehand technique was used over a 1-year period, from June 2016 to June 2017; all procedures were performed by neurosurgical residents. Measurements of C2 were obtained from preoperative CT scans, and breach rates were determined from coronal reconstructions on postoperative scans. Severity of breaches reflected the percentage of screw diameter beyond the cortical edge (I = < 25%; II = 26%–50%; III = 51%–75%; IV = 76%–100%).RESULTSNeurosurgical residents placed 40 C2 pedicle screws in 24 consecutively treated patients. All screws were placed by or under the guidance of Pham, who is a postgraduate year 7 (PGY-7) neurosurgical resident with attending staff privileges, with a PGY-2 to PGY-4 resident assistant. The authors found an average axial pedicle diameter of 5.8 mm, axial angle of 43.1°, sagittal angle of 23.0°, spinal canal diameter of 25.1 mm, and axial transverse foramen diameter of 5.9 mm. There were 17 screws placed by PGY-2 residents, 7 screws placed by PGY-4 residents, and 16 screws placed by the PGY-7 resident. The average screw length was 26.0 mm, with a screw diameter of 3.5 mm or 4.0 mm. There were 7 total breaches (17.5%), of which 4 were superior (10.0%) and 3 were lateral (7.5%). There were no medial breaches. The breaches were classified as grade I in 3 cases (42.9%), II in 3 cases (42.9%), III in 1 case (14.3%), and IV in no cases. There were 3 breaches that occurred via placement by a PGY-2 resident, 3 breaches by a PGY-4 resident, and 1 breach by the PGY-7 resident. There were no clinical sequelae due to these breaches.CONCLUSIONSFreehand placement of C2 pedicle screws can be done safely by neurosurgical residents in early training. When breaches occurred, they tended to be superior in location and related to screw length choice, and no breaches were found to be clinically significant. Controlled exposure to this unique anatomy is especially pertinent in the era of work-hour restrictions.

Accuracy of C2 pedicle screw placement using the anatomic freehand technique

2014 ◽  
Vol 125 ◽  
pp. 24-27 ◽  
Author(s):  
Mohamad Bydon ◽  
Dimitrios Mathios ◽  
Mohamed Macki ◽  
Rafael De la Garza-Ramos ◽  
Nafi Aygun ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Screw Placement ◽  
Pedicle Screw Placement ◽  
C2 Pedicle Screw ◽  
Freehand Technique

scholarly journals Accuracy of robot-guided versus freehand fluoroscopy-assisted pedicle screw insertion in thoracolumbar spinal surgery

2017 ◽  
Vol 42 (5) ◽  
pp. E14 ◽  
Author(s):  
Granit Molliqaj ◽  
Bawarjan Schatlo ◽  
Awad Alaid ◽  
Volodymyr Solomiichuk ◽  
Veit Rohde ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Spinal Instrumentation ◽  
Pedicle Screws ◽  
Screw Placement ◽  
Robotic Assistance ◽  
Anatomical Landmarks ◽  
Pedicle Screw Placement ◽  
Robot Assisted ◽  
Screw Insertion ◽  
Freehand Technique

OBJECTIVEThe quest to improve the safety and accuracy and decrease the invasiveness of pedicle screw placement in spine surgery has led to a markedly increased interest in robotic technology. The SpineAssist from Mazor is one of the most widely distributed robotic systems. The aim of this study was to compare the accuracy of robot-guided and conventional freehand fluoroscopy-guided pedicle screw placement in thoracolumbar surgery.METHODSThis study is a retrospective series of 169 patients (83 women [49%]) who underwent placement of pedicle screw instrumentation from 2007 to 2015 in 2 reference centers. Pathological entities included degenerative disorders, tumors, and traumatic cases. In the robot-assisted cohort (98 patients, 439 screws), pedicle screws were inserted with robotic assistance. In the freehand fluoroscopy-guided cohort (71 patients, 441 screws), screws were inserted using anatomical landmarks and lateral fluoroscopic guidance. Patients treated before 2009 were included in the fluoroscopy cohort, whereas those treated since mid-2009 (when the robot was acquired) were included in the robot cohort. Since then, the decision to operate using robotic assistance or conventional freehand technique has been based on surgeon preference and logistics. The accuracy of screw placement was assessed based on the Gertzbein-Robbins scale by a neuroradiologist blinded to treatment group. The radiological slice with the largest visible deviation from the pedicle was chosen for grading. A pedicle breach of 2 mm or less was deemed acceptable (Grades A and B) while deviations greater than 2 mm (Grades C, D, and E) were classified as misplacements.RESULTSIn the robot-assisted cohort, a perfect trajectory (Grade A) was observed for 366 screws (83.4%). The remaining screws were Grades B (n = 44 [10%]), C (n = 15 [3.4%]), D (n = 8 [1.8%]), and E (n = 6 [1.4%]). In the fluoroscopy-guided group, a completely intrapedicular course graded as A was found in 76% (n = 335). The remaining screws were Grades B (n = 57 [12.9%]), C (n = 29 [6.6%]), D (n = 12 [2.7%]), and E (n = 8 [1.8%]). The proportion of non-misplaced screws (corresponding to Gertzbein-Robbins Grades A and B) was higher in the robot-assisted group (93.4%) than the freehand fluoroscopy group (88.9%) (p = 0.005).CONCLUSIONSThe authors’ retrospective case review found that robot-guided pedicle screw placement is a safe, useful, and potentially more accurate alternative to the conventional freehand technique for the placement of thoracolumbar spinal instrumentation.

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