Postoperative Assessment of Pedicle Screws and Management of Breaches: A Survey among Canadian Spine Surgeons and a New Scoring System

Abstract

Study DesignThis study was designed as a survey amongst Canadian spine surgeon to determine a scoring system to standardize pedicle screw placement assessment.PurposeThis study aimed to obtain and analyze the opinions of spine surgeons regarding the assessment of pedicle screw accuracy, with the goal of establishing clinical guidelines for interventions for malpositioned pedicle screws.Overview of LiteratureAccurate placement of pedicle screws is challenging, and misalignment can lead to various complications. To date, there is no recognized gold standard for assessing pedicle screw placement accuracy. The literature is lacking studies attempting to standardize pedicle screw placement accuracy assessment.MethodsA survey of the clinical methods and imaging criteria that are used for assessing pedicle screw placement accuracy was designed and sent to orthopedic and neurosurgery spine surgeons from the Canadian Spine Society for their anonymous participation.ResultsThirty-five surgeons completed the questionnaire. The most commonly used modalities for assessing pedicle screw position postoperatively were plain X-rays (97%) and computed tomography (CT, 97%). In both symptomatic and asymptomatic patients, the most and least worrisome breaches were medial and anterior breaches, respectively. The majority of surgeons tended not to re-operate on asymptomatic breaches. More than 60% of surgeons would re-operate on patients with new-onset pain and a ≤4-mm medial or inferior breach in both thoracic and lumbar regions. If a patient experienced sensory loss and a breach on CT, in either the thoracic or lumbar levels, 90% and 70% of the surgeons would re-operate for a medial breach and an inferior breach, respectively.ConclusionsPostoperative clinical presentation and imaging findings are crucial for interpreting aberrant pedicle screw placement. This study presents a preliminary scoring system for standardizing the classification of pedicle screws.

The Effect of Thoracolumbar Pedicle Isthmus on Pedicle Screw Accuracy

“…Another recent study surveyed spine surgeons from various sites across Canada in order to ascertain their assessment of accuracy of pedicle screw placement. 28 The results suggested that both postoperative clinical findings and radiographic findings were crucial to surgeons’ interpretation of aberrant screw positioning. In recognizing this, they developed a scoring system to help classify pedicle screws misplacement and determine the need for revision.…”

“…In recognizing this, they developed a scoring system to help classify pedicle screws misplacement and determine the need for revision. 28 We acknowledge that a potential limitation of this retrospective study is that we are not using the isthmus width collected from the same patients in which we are calculating breach incidence. It is our assumption that the mean and standard deviation calculated by Zindrick et al 17 adequately represents the isthmus width in the general population, and as such the sample size was large enough to appropriately use a surrogate measure for isthmus width.…”

“…In recognizing this, they developed a scoring system to help classify pedicle screws misplacement and determine the need for revision. 28…”

“…The development of a widely accepted, validated breach assessment tool has been suggested but not implemented. 22,28 Floccari et al 29 conducted a survey among spine surgeons who were presented with CT scans of various degrees of breach and asked whether or not they would revise the pedicle screws. Although certain aspects of the breach, such as aortic or dural compromise, made the surgeons more likely to recommend a revision, there was no consensus on what should prompt revision.…”

Update on Imaging of Spinal Fixation Hardware

“…17a). 76 Anterior extrusion of the screw tips through the vertebral body could damage posterior mediastinal or retroperitoneal structures, most importantly the aorta.…”