Biomechanical evaluation of pedicle screws versus pedicle and laminar hooks in the thoracic spine

ABSTRACT Summary of Background Data: Multilevel posterior cervical instrumented fusions are becoming more prevalent in current practice. Biomechanical characteristics of the cervicothoracic junction may necessitate extending the construct to upper thoracic segments. However, fixation in upper thoracic spine can be technically demanding owing to transitional anatomy while suboptimal placement facilitates vascular and neurologic complications. Thoracic instrumentation methods include free-hand, fluoroscopic guidance, and CT-based image guidance. However, fluoroscopy of upper thoracic spine is challenging secondary to vertebral geometry and patient positioning, while image-guided systems present substantial financial commitment and are not readily available at most centers. Additionally, imaging modalities increase radiation exposure to the patient and surgeon while potentially lengthening surgical time. Materials and Methods: Retrospective review of 44 consecutive patients undergoing a cervicothoracic fusion by a single surgeon using the novel free-hand T1 pedicle screw technique between June 2009 and November 2012. A starting point medial and cephalad to classic entry as well as new trajectory were utilized. No imaging modalities were employed during screw insertion. Postoperative CT scans were obtained on day 1. Screw accuracy was independently evaluated according to the Heary classification. Results: In total, 87 pedicle screws placed were at T1. Grade 1 placement occurred in 72 (82.8%) screws, Grade 2 in 4 (4.6%) screws and Grade 3 in 9 (10.3%) screws. All Grade 2 and 3 breaches were <2 mm except one Grade 3 screw breaching 2-4 mm laterally. Only two screws (2.3%) were noted to be Grade 4, both breaching medially by less than 2 mm. No new neurological deficits or returns to operating room took place postoperatively. Conclusions: This modification of the traditional starting point and trajectory at T1 is safe and effective. It attenuates additional bone removal or imaging modalities while maintaining a high rate of successful screw placement compared to historical controls.

Download Full-text

Biomechanical evaluation of the primary stability of pedicle screws after augmentation with an innovative bone stabilizing system

Archives of Orthopaedic and Trauma Surgery ◽

10.1007/s00402-013-1842-2 ◽

2013 ◽

Vol 133 (11) ◽

pp. 1493-1499 ◽

Cited By ~ 12

Author(s):

K. Wegmann ◽

S. Gick ◽

C. Heidemann ◽

D. Pennig ◽

W. F. Neiss ◽

...

Keyword(s):

Pedicle Screws ◽

Primary Stability ◽

Biomechanical Evaluation

Download Full-text

P75. Is it safer to place pedicle screws in the lower thoracic spine than in the upper lumbar spine? Comparison of pedicle isthmic width of the lower thoracic and the upper lumbar spine using MRI

The Spine Journal ◽

10.1016/j.spinee.2005.05.290 ◽

2005 ◽

Vol 5 (4) ◽

pp. S145-S146

Author(s):

Elisha Ofiram ◽

David Polly ◽

Theodore Choma ◽

Thomas Gilbert

Keyword(s):

Lumbar Spine ◽

Thoracic Spine ◽

Pedicle Screws ◽

Lower Thoracic Spine

Download Full-text

Biomechanical evaluation of strategies for adjacent segment disease after lateral lumbar interbody fusion: is the extension of pedicle screws necessary?

BMC Musculoskeletal Disorders ◽

10.1186/s12891-020-3103-1 ◽

2020 ◽

Vol 21 (1) ◽

Cited By ~ 1

Author(s):

Ziyang Liang ◽

Jianchao Cui ◽

Jiarui Zhang ◽

Jiahui He ◽

Jingjing Tang ◽

...

Keyword(s):

Interbody Fusion ◽

Pedicle Screws ◽

Adjacent Segment Disease ◽

Adjacent Segment ◽

Lumbar Interbody Fusion ◽

Lateral Lumbar Interbody Fusion ◽

Biomechanical Evaluation

Download Full-text

ACCURACY OF PEDICLE SCREW INSERTION: A COMPARISON BETWEEN FLUOROSCOPIC GUIDANCE AND NAVIGATION TECHNIQUES

Acta Ortopédica Brasileira ◽

10.1590/1413-785220182606180635 ◽

2018 ◽

Vol 26 (6) ◽

pp. 397-400 ◽

Cited By ~ 2

Author(s):

Romero Pinto de Oliveira Bilhar ◽

Diego Ariel de Lima ◽

José Alberto Dias Leite ◽

Maximiliano Aguiar Porto

Keyword(s):

Thoracic Spine ◽

Pedicle Screws ◽

Computer Assisted ◽

Fluoroscopic Guidance ◽

Level Of Evidence ◽

Assisted Navigation ◽

Screw Insertion ◽

Navigation Group ◽

Duration Of Surgery ◽

Navigation Equipment

ABSTRACT Objectives: To compare the accuracy of insertion of pedicle screws into the thoracic spine using fluoroscopic guidance or computer-assisted navigation techniques. Methods: Eight cadaveric thoracic spines were divided into two groups: the fluoroscopy group, in which pedicle screws were inserted with the guidance of a C-arm device, and the navigation group, in which insertion of the screws was monitored using computer-assisted navigation equipment. All procedures were performed by the same spinal surgeon. The rate of pedicle breach was compared between the two groups. Results: There was one intra-canal perforation in each group. Both perforations were medial in direction, and the breaches were 2 to 4 mm deep. There were no statistically significant differences in breach rate between the two groups. Conclusions: The accuracy of insertion of pedicle screws in the thoracic spine using computer-assisted navigation is equivalent to that achieved using fluoroscopic guidance. Computer-assisted navigation improves the safety of the surgical team during the procedure due to the absence of exposure to radiation. Therefore, there is a need for future randomized controlled trials to be conducted in the clinical setting to evaluate other outcomes, including duration of surgery and blood loss during the procedure. Level of evidence IV.

Download Full-text

Accuracy and safety of pedicle screw fixation in thoracic spine trauma

Journal of Neurosurgery Spine ◽

10.3171/spi.2006.5.6.520 ◽

2006 ◽

Vol 5 (6) ◽

pp. 520-526 ◽

Cited By ~ 41

Author(s):

Charles G. Fisher ◽

Vic Sahajpal ◽

Ory Keynan ◽

Michael Boyd ◽

Douglas Graeb ◽

...

Keyword(s):

Pedicle Screw ◽

Thoracic Spine ◽

Pedicle Screws ◽

Pedicle Screw Fixation ◽

Spine Fractures ◽

Chi Square ◽

Clinical Safety ◽

Thoracic Spine Fractures ◽

Screw Position ◽

Pedicle Wall

Object The authors evaluated the accuracy of placement and safety of pedicle screws in the treatment of unstable thoracic spine fractures. Methods Patients with unstable fractures between T-1 and T-10, which had been treated with pedicle screw (PS) placement by one of five spine surgeons at a referral center were included in a prospective cohort study. Postoperative computed tomography scans were obtained using 3-mm axial cuts with sagittal reconstructions. Three independent reviewers (C.B., V.S., and D.G.) assessed PS position using a validated grading scale. Comparison of failure rates among cases grouped by selected baseline variables were performed using Pearson chi-square tests. Independent peri- and postoperative surveillance for local and general complications was performed to assess safety. Twenty-three patients with unstable thoracic fractures treated with 201 thoracic PSs were analyzed. Only PSs located between T-1 and T-12 were studied, with the majority of screws placed between T-5 and T-10. Of the 201 thoracic PSs, 133 (66.2%) were fully contained within the pedicle wall. The remaining 68 screws (33.8%) violated the pedicle wall. Of these, 36 (52.9%) were lateral, 27 (39.7%) were medial, and five (7.4%) were anterior perforations. No superior, inferior, anteromedial, or anterolateral perforations were found. When local anatomy and the clinical safety of screws were considered, 98.5% (198 of 201) of the screws were probably in an acceptable position. No baseline variables influenced the incidence of perforations. There were no adverse neurological, vascular, or visceral injuries detected intraoperatively or postoperatively. Conclusions In the vast majority of cases, PSs can be placed in an acceptable and safe position by fellowship-trained spine surgeons when treating unstable thoracic spine fractures. However, an unacceptable screw position can occur.

Download Full-text