Are We Underestimating the Significance of Pedicle Screw Misplacement?

Vishal Sarwahi, Stephen F. Wendolowski, Rachel Gecelter, Terry Amaral, Yungtai Lo, Beverly Ann Thornhill

Research output: Contribution to journal › Article

14 Citations (Scopus)

Abstract

STUDY DESIGN.: A retrospective review of charts, XRs and CT scans was performed. OBJECTIVE.: To evaluate the accuracy of pedicle screw placement using a novel classification system to determine potentially significant screw misplacement. SUMMARY OF BACKGROUND DATA.: The accuracy rate of pedicle screw (PS) placement varies from 85–95% in the literature. This demonstrates technical ability but does not represent the impact of screw misplacement on individual patients. This study quantifies the rate of screw misplacement on a per-patient basis to highlight its effect on potential morbidity. METHODS.: A retrospective review of charts, XRs and low-dose CT scans of 127 patients who underwent spinal fusion with pedicle screws for spinal deformity was performed. Screws were divided into four categories: Screws at Risk (SAR), Indeterminate Misplacements (IMP), Benign Misplacements (BMP), Accurately Placed (AP). RESULTS.: 2724 screws were placed in 127 patients. 2396 screws were placed accurately (87.96%). 247 screws (9.07%) were BMP, 52 (1.91%) were IMP, and 29 (1.06%) were considered SAR. Per-patient analysis showed 23 (18.11%) of patients had all screws AP. 35 (27.56%) had IMP and 18 (14.17%) had SAR. Risk factor analysis showed smaller Cobb angles increased likelihood of all screws being AP. Sub-analysis of AIS patients showed no curve or patient characteristic that correlated with IMP or SAR. Over 40% of patients had screws with either some/major concern. CONCLUSIONS.: verall reported screw misplace is low, but does not reflect the potential impact on patient morbidity. Per-patient analysis reveals more concerning numbers toward screw misplacement. With increasing pedicle screw usage, the number of patients with misplaced screws will likely increase proportionally. Better strategies need to be devised for evaluation of screw placement, including establishment of a national database of deformity surgery, use of intra-operative image guidance, and reevaluation of postoperative low-dose CT imaging.Level of Evidence: 3

Original languageEnglish (US)
JournalSpine
DOIs
StateAccepted/In press - Nov 30 2015

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Pedicle Screws
Morbidity
Spinal Fusion
Statistical Factor Analysis
Databases

ASJC Scopus subject areas

  • Clinical Neurology
  • Orthopedics and Sports Medicine

Cite this

Are We Underestimating the Significance of Pedicle Screw Misplacement? / Sarwahi, Vishal; Wendolowski, Stephen F.; Gecelter, Rachel; Amaral, Terry; Lo, Yungtai; Thornhill, Beverly Ann.

In: Spine, 30.11.2015.

Research output: Contribution to journal › Article

Sarwahi, V, Wendolowski, SF, Gecelter, R, Amaral, T, Lo, Y & Thornhill, BA 2015, 'Are We Underestimating the Significance of Pedicle Screw Misplacement?', Spine. https://doi.org/10.1097/BRS.0000000000001318
Sarwahi V, Wendolowski SF, Gecelter R, Amaral T, Lo Y, Thornhill BA. Are We Underestimating the Significance of Pedicle Screw Misplacement? Spine. 2015 Nov 30. https://doi.org/10.1097/BRS.0000000000001318
Sarwahi, Vishal ; Wendolowski, Stephen F. ; Gecelter, Rachel ; Amaral, Terry ; Lo, Yungtai ; Thornhill, Beverly Ann. / Are We Underestimating the Significance of Pedicle Screw Misplacement?. In: Spine. 2015.
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abstract = "STUDY DESIGN.: A retrospective review of charts, XRs and CT scans was performed. OBJECTIVE.: To evaluate the accuracy of pedicle screw placement using a novel classification system to determine potentially significant screw misplacement. SUMMARY OF BACKGROUND DATA.: The accuracy rate of pedicle screw (PS) placement varies from 85–95{\%} in the literature. This demonstrates technical ability but does not represent the impact of screw misplacement on individual patients. This study quantifies the rate of screw misplacement on a per-patient basis to highlight its effect on potential morbidity. METHODS.: A retrospective review of charts, XRs and low-dose CT scans of 127 patients who underwent spinal fusion with pedicle screws for spinal deformity was performed. Screws were divided into four categories: Screws at Risk (SAR), Indeterminate Misplacements (IMP), Benign Misplacements (BMP), Accurately Placed (AP). RESULTS.: 2724 screws were placed in 127 patients. 2396 screws were placed accurately (87.96{\%}). 247 screws (9.07{\%}) were BMP, 52 (1.91{\%}) were IMP, and 29 (1.06{\%}) were considered SAR. Per-patient analysis showed 23 (18.11{\%}) of patients had all screws AP. 35 (27.56{\%}) had IMP and 18 (14.17{\%}) had SAR. Risk factor analysis showed smaller Cobb angles increased likelihood of all screws being AP. Sub-analysis of AIS patients showed no curve or patient characteristic that correlated with IMP or SAR. Over 40{\%} of patients had screws with either some/major concern. CONCLUSIONS.: verall reported screw misplace is low, but does not reflect the potential impact on patient morbidity. Per-patient analysis reveals more concerning numbers toward screw misplacement. With increasing pedicle screw usage, the number of patients with misplaced screws will likely increase proportionally. Better strategies need to be devised for evaluation of screw placement, including establishment of a national database of deformity surgery, use of intra-operative image guidance, and reevaluation of postoperative low-dose CT imaging.Level of Evidence: 3",
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AU - Sarwahi, Vishal

AU - Wendolowski, Stephen F.

AU - Gecelter, Rachel

AU - Amaral, Terry

AU - Lo, Yungtai

AU - Thornhill, Beverly Ann

PY - 2015/11/30

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N2 - STUDY DESIGN.: A retrospective review of charts, XRs and CT scans was performed. OBJECTIVE.: To evaluate the accuracy of pedicle screw placement using a novel classification system to determine potentially significant screw misplacement. SUMMARY OF BACKGROUND DATA.: The accuracy rate of pedicle screw (PS) placement varies from 85–95% in the literature. This demonstrates technical ability but does not represent the impact of screw misplacement on individual patients. This study quantifies the rate of screw misplacement on a per-patient basis to highlight its effect on potential morbidity. METHODS.: A retrospective review of charts, XRs and low-dose CT scans of 127 patients who underwent spinal fusion with pedicle screws for spinal deformity was performed. Screws were divided into four categories: Screws at Risk (SAR), Indeterminate Misplacements (IMP), Benign Misplacements (BMP), Accurately Placed (AP). RESULTS.: 2724 screws were placed in 127 patients. 2396 screws were placed accurately (87.96%). 247 screws (9.07%) were BMP, 52 (1.91%) were IMP, and 29 (1.06%) were considered SAR. Per-patient analysis showed 23 (18.11%) of patients had all screws AP. 35 (27.56%) had IMP and 18 (14.17%) had SAR. Risk factor analysis showed smaller Cobb angles increased likelihood of all screws being AP. Sub-analysis of AIS patients showed no curve or patient characteristic that correlated with IMP or SAR. Over 40% of patients had screws with either some/major concern. CONCLUSIONS.: verall reported screw misplace is low, but does not reflect the potential impact on patient morbidity. Per-patient analysis reveals more concerning numbers toward screw misplacement. With increasing pedicle screw usage, the number of patients with misplaced screws will likely increase proportionally. Better strategies need to be devised for evaluation of screw placement, including establishment of a national database of deformity surgery, use of intra-operative image guidance, and reevaluation of postoperative low-dose CT imaging.Level of Evidence: 3

AB - STUDY DESIGN.: A retrospective review of charts, XRs and CT scans was performed. OBJECTIVE.: To evaluate the accuracy of pedicle screw placement using a novel classification system to determine potentially significant screw misplacement. SUMMARY OF BACKGROUND DATA.: The accuracy rate of pedicle screw (PS) placement varies from 85–95% in the literature. This demonstrates technical ability but does not represent the impact of screw misplacement on individual patients. This study quantifies the rate of screw misplacement on a per-patient basis to highlight its effect on potential morbidity. METHODS.: A retrospective review of charts, XRs and low-dose CT scans of 127 patients who underwent spinal fusion with pedicle screws for spinal deformity was performed. Screws were divided into four categories: Screws at Risk (SAR), Indeterminate Misplacements (IMP), Benign Misplacements (BMP), Accurately Placed (AP). RESULTS.: 2724 screws were placed in 127 patients. 2396 screws were placed accurately (87.96%). 247 screws (9.07%) were BMP, 52 (1.91%) were IMP, and 29 (1.06%) were considered SAR. Per-patient analysis showed 23 (18.11%) of patients had all screws AP. 35 (27.56%) had IMP and 18 (14.17%) had SAR. Risk factor analysis showed smaller Cobb angles increased likelihood of all screws being AP. Sub-analysis of AIS patients showed no curve or patient characteristic that correlated with IMP or SAR. Over 40% of patients had screws with either some/major concern. CONCLUSIONS.: verall reported screw misplace is low, but does not reflect the potential impact on patient morbidity. Per-patient analysis reveals more concerning numbers toward screw misplacement. With increasing pedicle screw usage, the number of patients with misplaced screws will likely increase proportionally. Better strategies need to be devised for evaluation of screw placement, including establishment of a national database of deformity surgery, use of intra-operative image guidance, and reevaluation of postoperative low-dose CT imaging.Level of Evidence: 3

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