Intraoperative 3D imaging with cone-beam computed tomography leads to revision of pedicle screws in dorsal instrumentation: a retrospective analysis

Abstract

Background Correct positioning of pedicle screws can be challenging. Intraoperative imaging may be helpful. The purpose of this study was to evaluate the use of intraoperative 3D imaging with a cone-beam CT. The hypotheses were that intraoperative 3D imaging (1) will lead to an intraoperative revision of pedicle screws and (2) may diminish the rate of perforated screws on postoperative imaging. Methods Totally, 351 patients (age 60.9 ± 20.3 a (15–96); m/f 203/148) underwent dorsal instrumentation with intraoperative 3D imaging with 2215 pedicle screws at a trauma center level one. This study first evaluates intraoperative imaging. After this, 501 screws in 73 patients (age 62.5 ± 19.7 a; m/f 47/26) of this collective were included in the study group (SG) and their postoperative computed tomography was evaluated with regard to screw position. Then, 500 screws in 82 patients (age 64.8 ± 14.4 a; m/f 51/31) as control group (CG), who received the screws with conventional 2D fluoroscopy but without 3D imaging, were evaluated with regard to screw position. Results During the placement of the 2215 pedicle screws, 158 (7.0%) intraoperative revisions occurred as a result of 3D imaging. Postoperative computed tomography of the SG showed 445 (88.8%) screws without relevant perforation (type A + B), of which 410 (81.8%) could be classified as type A and 35 (7.0%) could be classified as type B. Fifty-six (11.2%) screws in SG showed relevant perforation (type C–E). In contrast, 384 (76.8%) screws in the CG were without relevant perforation (type A + B), of which 282 (56.4%) could be classified as type A and 102 (20.4%) as type B. One hundred and sixteen (23.2%) screws in the CG showed relevant perforation (type C–E). Conclusion This study shows that correct placement of pedicle screws in spine surgery with conventional 2D fluoroscopy is challenging. Misplacement of screws cannot always be prevented. Intraoperative 3D imaging with a CBCT can be helpful to detect and revise misplaced pedicle screws intraoperatively. The use of intraoperative 3D imaging will probably minimize the number of revision procedures due to perforating pedicle screws.

Is the postoperative pedicle screw position after dorsal instrumentation with or without intraoperative cone beam CT imaging worse in patients with obesity than in normal-weight patients?

“…Therefore, other techniques, such as CBCT, have been developed to close this intraoperative gap. Additionally, good (type A + B according to Gertzbein) pedicle screw positions have been observed in 88.8–94.1% patients after dorsal instrumentation with intraoperative imaging by a CBCT scan [ 15 , 19 ]. Moreover, it has been shown that intraoperative imaging with CBCT is not inferior to intraoperative CT [ 20 , 21 ].…”

“…In all patients, pedicle screws were inserted and cannulated over previously inserted Kirschner wires during dorsal instrumentation, and the intraoperative imaging procedure was performed as previously described [ 15 ]. The decision whether intraoperative CBCT imaging was performed was made by the surgeon.…”

Intraoperative Bildgebung, Navigation und Robotik an der Wirbelsäule

“…Des Weiteren können somit die Anzahl der Revisionseingriffe reduziert und die damit einhergehenden Risiken und zusätzlichen Kosten vermieden werden. Der Einsatz der CBCT in der Wirbelsäulenchirurgie führt in Abhängigkeit von der Literatur in bis zu 7 % der Fälle zur intraoperativen Korrektur von Implantatlage oder Reposition [6]. Zudem konnte aufgezeigt werden, dass die Sensitivität bei der Visualisierung von Kortikalisverletzungen durch Pedikelschrauben an der Wirbelsäule vergleichbar ist mit dem postoperativen CT [18].…”

“…Untersuchungen, die sich mit postoperativen Revisionsraten bei dorsalen Instrumentierungen der Wirbelsäule beschäftigen, haben bereits gezeigt, dass der Einsatz der intraoperativen 3-D-Bildgebung einen positiven Effekt auf die Schraubenplatzierung hat. Intraoperative Fehllagen konnten, aufgrund der zusätzlichen Informationen aus den 3-D-Datensätzen erkannt und unmittelbar korrigiert werden [6,9]. Darüber hinaus bieten Navigationstechniken in Kombination mit einer intraoperativen CBCT (Cone-Beam-Computertomografie) oder CT durch eine präzise Planung von Schraubengröße und -trajektorie die Möglichkeit, eine Implantatfehllage zu verhindern [6,10,11].…”

“…Intraoperative Fehllagen konnten, aufgrund der zusätzlichen Informationen aus den 3-D-Datensätzen erkannt und unmittelbar korrigiert werden [6,9]. Darüber hinaus bieten Navigationstechniken in Kombination mit einer intraoperativen CBCT (Cone-Beam-Computertomografie) oder CT durch eine präzise Planung von Schraubengröße und -trajektorie die Möglichkeit, eine Implantatfehllage zu verhindern [6,10,11].…”