Article
Unskilled unawareness prolongs the early learning curve in robotic spine surgery
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Authors
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Bawarjan Schatlo
- Department of Neurosurgery, University Medicine Göttingen, Georg-August-University of Göttingen, Göttingen, Germany
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Ramon Martinez
- Department of Neurosurgery, University Medicine Göttingen, Georg-August-University of Göttingen, Göttingen, Germany
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Awad Alaid
- Department of Neurosurgery, University Medicine Göttingen, Georg-August-University of Göttingen, Göttingen, Germany
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Reza Akhavan-Sigari
- Department of Neurosurgery, University Medicine Göttingen, Georg-August-University of Göttingen, Göttingen, Germany
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Florian Stockhammer
- Department of Neurosurgery, University Medicine Göttingen, Georg-August-University of Göttingen, Göttingen, Germany
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Veit Rohde
- Department of Neurosurgery, University Medicine Göttingen, Georg-August-University of Göttingen, Göttingen, Germany
| Published: | June 2, 2015 |
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Outline
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Objective: Robotic assistance for the placement of pedicle screws has been established as a safe technique. Nonetheless rare instances of screw misplacement have been reported. The aim of the present study is to assess whether experience and time affect the accuracy of screws placed with the help of the Spine Assist robot system.
Method: Out of 217 patients requiring thoracolumbar pedicle screw instrumentation from 2008 to 2013 we included 161 who were operated by one of four surgeons with an experience of >15 robot cases. Postoperative CT was performed in all cases. Primary outcome measure was accuracy of screw placement and a dichotomous distinction between pedicle breach less than 3mm as acceptable and >3mm defined as misplacement. Surgeons were dichotomized into an early and experienced period in increments of five surgeries. Receiver operator characteristics (ROC) with area under the curves (AUC) were calculated to assess the relationship of experience with the rate of surgeries with at least one misplaced screw per surgery.
Results: In 161 surgeries, 782 pedicle screws were placed with the aid of the robot system. Overall, 150 (93%) of surgeries were performed without evidence of screw misplacement. In 11 surgeries (7%) a screw misplacement was detected. The number of surgeries with misplacement had a peak at 15 surgeries. In all surgeons, the first five surgeries had a misplacement rate of 0%, while an experience of <15 surgeries was associated with at least one suboptimal screw trajectory in 45% of cases. After 25 surgeries, these rates decreased to a nadir of 18% (AUC 0.71, p=0.10; sensitivity: 100%, specificity: 57%).
Conclusions: All of our surgeons had no single screw misplacement in their first five robot-assisted cases. A peak in screw inaccuracies occurred between cases 10 and 20. Whether this is due to a precocious leap in one's self-awareness remains speculative. However, one potential explanation could be a transition from decreased supervision (unskilled but aware) to increased confidence of a surgeon (unskilled but unaware) who adopts this new technique prior to mastering it (skilled). We therefore advocate ensuring competent supervision for new surgeons at least during the first 25 procedures of robotic spine surgery to optimize the accuracy of robot-assisted pedicle screws.
