CT Assessment of accuracy of lumbar pedicle screw insertion (An applied comparative evaluation of conventional and percutaneous techniques (original) (raw)
Related papers
Accuracy of C2 pedicle screw placement using the anatomic freehand technique
Clinical Neurology and Neurosurgery, 2014
Objective: The objective of this study is to evaluate the incidence and prognostic factors of breach rates following the placement of C2 pedicle screws using the anatomic, freehand technique. Methods: We retrospectively reviewed the medical records of all patients who underwent C2 transpedicular instrumentation over six years at a single institution. All intraoperative, image-guided techniques were excluded. Breaches were ascertained from immediate postoperative CT images. All images were analyzed by three independent reviewers. The screw length was correlated with (1) the breach rate and (2) the breach severity. Severity of the breached screws reflects the screw circumference (0-360 • ) perforating the pedicle wall (Grade 1-Grade 4). Results: Of the 341 C2 pedicle screws inserted in 181 patients, the average screw length was 22.93 ± 3.7 mm. The average distance from the foramen transversarium to the screw insertion point was 13.17 ± 2.63 mm. The distance from the medial rim of the pedicle to the dura of spinal cord was 3.53 ± 1.57 mm. Of the 341 screws, the overall breach rate was 17.3% (n = 59). Of the 59 breaches, 89.83% of screws (n = 53) breaching the spinal canal was statistically significantly higher than the 10.17% of screws (n = 6) breaching the foramen transversarium (p < 0.001). Moreover, 27 (45.8%) were Grade 1, 16 (27.1%) Grade 2, 6 (10.2%) Grade 3, and 10 (16.9%) Grade 4. None of the C2 breaches resulted in neurological sequela. No association was found between breach rate and gender, race or age. While the average screw length was 22.93 ± 3.7 mm [12-34 mm], screw length did not predict a cortical violation (p = 0.4) or severity of the breach (p = 0.42) in a multiple regression model. Conclusions: In this cohort study on the anatomic freehand placement of C2 pedicle screws, the breach rate was 17.3%. Lateral breaches were more common than medial breaches. Screw length was not statistically correlated with cortical violation or severity of breach. Therefore, screw length is not a prognostic factor for C2 pedicle screw misplacement.
Journal of Spinal Disorders & Techniques, 2006
The objective of this study is to evaluate the effectiveness of a specific methodology for plain radiographic assessment of lumbar pedicle screw position. To evaluate the effectiveness of using orthogonal plain radiographs and a systematic method of interpretation, developed by the senior author, in assessing the placement of lumbar and lumbosacral pedicle screws. This was an adult cadaver study of the accuracy of using plain radiographs or computed tomography to assess pedicle screw position. Plain radiographs were performed and compared with computed tomography (CT) scans. Gross anatomic dissections were performed to directly confirm screw position. Variables, including screw material, radiographic view, and screw dimensions, were assessed for their effect on the ability of physicians to determine pedicle screw position. Multiple readers were included in the study, including 1 spine Fellow, 3 experienced orthopedic spine surgeons, and 1 neuroradiologist. Five adult cadaveric spines were instrumented with titanium pedicle screws from L1 to S1. Screws were placed outside the confines of the pedicle in all 4 quadrants or within the pedicle using a Latin-Square design. Each cadaver was imaged with orthogonal radiographs and high-resolution CT scans. The spines were then reimaged after the instrumentation was replaced with stainless steel screws placed in the identical position. Finally, each spine was dissected to assess the exact position of the screws. Images were read in a blinded fashion by 1 spine fellow, 2 staff surgeons, and a staff radiologist. The results were compared with the known screw positions at dissection. In total, 120 pedicle screws were placed, 44 (38%) outside the confines of the pedicle. Sensitivity, defined as the percent of the misplaced screws that were correctly identified, was similar across the 3 diagnostic tests, but markedly improved when all CT formats were considered together. Similarly, specificity, defined as the percent of screws correctly read as being placed within the pedicle, was independent of radiographic examination. Sensitivity of the radiographic technique was 70.1% and specificity was 83.0%, whereas sensitivity for CT scans was 84.7% and specificity was 89.7%. There was an observed association with anatomic level, with a consistently less accuracy in detecting screw position at L1 with plain x-ray (P=0.001). Additionally, correct position of stainless steel screws was more difficult to detect as compared with titanium (P=0.033) using either x-rays or CT. Other variables examined, such as screw length and screw diameter, did not have an effect on the ability to read the positioning. CT scans, often considered the &amp;amp;amp;amp;amp;quot;gold standard&amp;amp;amp;amp;amp;quot; for clinical assessment of pedicle screw placement, have limitations when validated with gross anatomical dissection. The described systematic method for evaluating pedicle screw placement using orthogonal plain radiographs attained accuracy comparable to high-resolution CT scans.
CT accuracy of percutaneous versus open pedicle screw techniques: a series of 1609 screws
European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2015
Traditional open exposure for posterior instrumentation requires significant soft tissue mobilization and causes significant blood loss and increased recovery time. Mal-placed screws can injure nerve roots, the spinal cord, viscera, vasculature and the cardiopulmonary system. Placement of pedicle screws using a minimally invasive technique can decrease bleeding risk, damage to soft tissues, and post-operative pain. The purpose of this study is to compare the radiographic accuracy of open free-hand versus percutaneous technique for pedicle screw placement. Consecutive patients undergoing thoracolumbar surgery from September 2006 to October 2011 with post-operative CT imaging were included in this study. Three-dimensional screw positioning within the pedicle and the vertebral body was assessed on CT. The magnitude and location of violations were measured and recorded. Facet breaches at the cephalad and caudad ends of the construct were documented and graded. Two-hundred and twenty-thr...
Asian spine journal, 2018
This study was designed as a survey amongst Canadian spine surgeon to determine a scoring system to standardize pedicle screw placement assessment. This 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. Accurate 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. A 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. Thirty-five surgeons completed the questionnaire. The most commonly use...
The Spine Journal, 2014
Background Context: We retrospectively analyzed a total of 1218 pedicle screws for accuracy, with postoperative computed tomography, in 198 patients who were operated on between March of 2004 and September of 2012. Purpose: The purpose of this study was to determine the incidence of screw misplacement in patients who received a transpedicular screw fixation with intraoperative fluoroscopy in the lateral and lateral with anteroposterior positions. The results are compared between two groups. Study Design: Retrospective comparative study of accuracy of pedicle screw placement in thoracal and lumbar spine. Patient sample: The sample consists of 198 consecutive patients who underwent transpedicular screw fixation. Outcome Measures: Accuracy of screw placement was evaluated by postoperative CT scan. Misplacement was defined in cases where more than 25% of the screw size was residing outside of the pedicle. Methods: The indications for hardware placement, radiologic studies, patient demographics, and reoperation rates were recorded. Five hundred and twenty-eight screws (Group A, n=81) were inserted into the vertebral body with the assistance of lateral fluoroscopy only, whereas six hundred and ninety screws (Group B, n=117) were inserted with the assistance of lateral fluoroscopy, and the final positions of the screws were checked with anteroposterior fluoroscopy. Results: A total of 1218 screws were analyzed, with 962 screws having been placed at the lumbosacral region, and 256 screws at the thoracal region. According to the postoperative CT-scan, twenty-seven screws (2.2%) were identified as breaching the pedicle. Nineteen of them (3.6%) were in Group A, whereas eight of them (1.16%) were in Group B. The rate of pedicle breaches was significantly different between Group A and Group
Journal of Spine, 2017
Background: Transpedicular screw fixation in the Axis is difficult due to its relation with adjacent anatomic features. Successful placement requires a sufficient understanding of axis pedicle. Objective: The aim was to assess length and width of the C2 pedicle in Moroccan population in order to evaluate the safety of pedicle screw fixation. Patients and methods: We evaluated the C2 pedicle morphology using computed tomography (CT) imaging in 100 patients (30 females and 70 males; age range, 18-70; mean, 36,2 ± 11,9 years). Axial CT cutting was made at 1.25 mm intervals. The measurements of C2 pedicles were performed on CT images using its measurement tools. The pedicle transverse width was defined as the mediolateral diameter of the pedicle isthmus. Pedicle length (distance from the posterior cortex of the lateral mass to the middle of the vertebral body). Results: The overall mean pedicle transverse widths (PTW) were 5.3 mm (4.1 to 7.1 mm), in males were 5.2 ± 0.5 mm and 5 ± 0.4 mm in females. The overall mean pedicle lengths (PL) were ranged from 19,7 to 26.7 mm with average 22.5 mm. The mean PL in female was 21.8 ± 1.4 mm and 22.8 ± 1.7 mm in male. The mean PTW and PL were greater in males than in females at both sides, and this difference was statistically significant. On the other hand, they were not correlated to age in our adult patients. Conclusion: Our findings suggest that there were significant differences between individuals and ethnics. The preoperative CT scans undergoing cervical transpedicular fixation should be thoroughly analyzed for successful pedicle screws placement.
Accuracy of pedicle screw insertion: A prospective CT study in 30 low back patients
European Spine Journal, 1997
A prospective study of the accuracy of titanium pedicle screw placement in 30 low back operations was performed. The postoperative plain radiographs and CT reformation images were evaluated by two independent radiologists. Thirty-two out of 152 screws (21%) perforated the pedicle cortex. One-tenth of the perforations was detected with conventional radiography. In ten patients (33%) all the screws were located within the pedicle. The clinical significance of this study lies in the finding that pedicle perforations are more frequent than is generally believed and that, in spite of the many malplacements, no screw that perforated by less than 4.0 m m caused neurological problems. Only one nerve root lesion was detected.
Acta Neurochirurgica, 2017
Background The spatial and directional accuracy of the positioning of pedicle screws in the lumbosacral spine with conventional open surgery assessed by computed tomography (CT) has been published in several studies, systematic reviews and meta-analyses with a short-term follow-up. Inaccurate pedicle screw insertion may cause neurologic symptoms and weakens the construct. Methods The data of 147 patients operated on with transpedicular screw fixation based on anatomical landmarks, supported by fluoroscopy, by a senior neurosurgeon in our clinic between 2000 and 2010 were analyzed retrospectively. The accuracy of the pedicle screw position was assessed by using postoperative CT images and graded in 2-mm increments up to 6 mm by two independent surgeons and partly by an independent radiologist. Results A total of 837 lumbosacral pedicle screws were inserted in 147 randomly selected patients by a senior neurosurgeon. A mean accuracy of 85.7% of the screws being inside the pedicles was identified by the surgeon observers, with 3.3% being perforated 4 mm or more outside the pedicles. Postoperative neurologic symptoms were observed on the side corresponding to the breach in an average of 25.9% of patients with pedicle perforations, and 89.2% of the misplaced screws were either medially or inferiorly inserted. Conclusions Screw application reached a mean accuracy of 85.7% based on anatomical landmarks supported by fluoroscopy, warranting computer-assisted navigation for increased accuracy. Our results of 24 patients (16.3%) with the breached screws indicate that the direction of the breach may be more important than the absolute deviation in causing new neurologic symptoms.
The Effect of Thoracolumbar Pedicle Isthmus on Pedicle Screw Accuracy
Global Spine Journal, 2019
Study Design: Retrospective analysis. Objectives: Aberrant pedicle screws can cause serious neurovascular complications. We propose that a predominant factor of pedicle screw breach is the vertebral anatomy at a given spinal level. We aim to investigate the inverse correlation between breach incidence and vertebral isthmus width. Methods: The computed tomography scans of patients undergoing thoracolumbar surgery were retrospectively reviewed. Breaches were categorized as minor (<2 mm) or major (>2 mm). Breach incidence was stratified by spinal level. Average isthmus width was then compared to the collected breach incidences. A regression analysis and Pearson’s correlation were performed. Results: A total of 656 pedicle screws were placed in 91 patients with 233 detected breaches. Incidence of major breach was 6.3%. Four patients developed post-operative radiculopathy due to breach. Breach incidence was higher in the thoracic than lumbar spine (Fisher’s exact test, P < .0001...
A New Method for Detecting Pedicular Wall Perforation During Pedicle Screw Insertion
Spine, 2001
Study Design. Sensitivity, specificity, and predictive value analyses of a method that can be used to detect pedicular wall perforation during pedicle screw insertion were assessed. Objective. To determine the accuracy of observing the fatty material expelled during pedicle screw insertion for detecting pedicular wall perforations. Summary of Background Data. Although many methods for safe and accurate insertion of a pedicle screw are described, the rates of misplacement still are high, and complications may occur from improper placement of pedicle screws. Computer-assisted insertion techniques are reported to be very accurate, but these techniques are not yet commonly available. Methods. In this study, 74 pedicle screw insertions were observed for the material expelled after drilling for the pedicle screw. The outflows of blood and fatty particles were recorded separately. The position of the pedicle screws after surgery was verified by computed tomography. The specificity, sensitivity, positive and negative predictive values, and kappa statistics were assessed. Results. Visible fatty particles were observed during 51 pedicle screw insertions. The histologic analysis showed that the fatty particles were coming from the bone marrow of the corpus. For the observation of fatty particles in detecting perforations along the pedicle screw pathway, the specificity was 98%, the sensitivity 73%, the positive predictive value 84%, the negative predictive value 95%, and the kappa statistic 0.74. Conclusions. The observation of fatty particles in the blood that comes out after drilling for the pedicle screw may indicate that there is no perforation along the pedicle screw pathway. The observation is easy to perform and does not require any special instruments. Therefore, it can be used alone or in combination with other methods to improve the accuracy of pedicle screw insertion.