Navigationsgestützte Rekonstruktion der vorderen Säule bei Verletzungen im Brustwirbel- und thorakolumbalen Übergangsbereich

Spinal Navigation for Lateral Instrumentation of the Thoracolumbar Spine

BACKGROUND AND OBJECTIVES

Three-dimensional imaging-based navigation in spine surgery is mostly applied for pedicle screw placement. However, its potential reaches beyond. In this study, we analyzed the incorporation of spinal navigation for lateral instrumentation of the thoracolumbar spine in clinical routine at a high-volume spine center.

METHODS

Patients scheduled for lateral instrumentation were prospectively enrolled. A reference array was attached to the pelvis, and a computed tomography scan was acquired intraoperatively. A control computed tomography scan was routinely performed after final cage placement, replacing conventional 2-dimensional X-ray imaging.

RESULTS

145 cases were enrolled from April to October 2021 with a median of 1 (1-4) level being instrumented. Indications for surgery were trauma (35.9%), spinal infection (31.7%), primary and secondary tumors of the spine (17.2%), and degenerative spine disease (15.2%). The duration of surgery after the first scan was 98 ± 41 (20-342) minutes. In total, 190 cages were implanted (94 expandable cages for vertebral body replacement (49.5%) and 96 cages for interbody fusion [50.5%]). Navigation was successfully performed in 139 cases (95.9%). The intraoperative mental load was rated on a scale from 0 to 150 (maximal effort) by the surgeons, showing a moderate effort (median 30 [10-120]).

CONCLUSION

Three-dimensional imaging-based spinal navigation can easily be incorporated in clinical routine and serves as a reliable tool to achieve precise implant placement in lateral instrumentation of the spine. It helps to minimize radiation exposure to the surgical staff.

Comparison of Effect of Navigation Versus No Navigation on Vertebral Body Screw Placement in Anterior Approach Surgery for Thoracolumbar Burst Fractures: A Randomized Controlled Trial

OBJECTIVE

We evaluated the effects of using a navigation technique with anterior approach surgery for thoracolumbar burst fractures on vertebral body screw placement and discussed its effects on the long-term prognosis of patients.

METHODS

We performed a prospective study of patients who had undergone anterior approach thoracolumbar surgery from May 2018 to August 2019. The 40 patients were randomly divided into the navigation group (NG) and control group (CG). In the NG, vertebral body screw placement was performed with 2-dimensional navigation guidance. For the CG, no navigation guidance was used. The clinical and radiological evaluations of the 2 groups were compared preoperatively, immediately after surgery, and at the final follow-up. Paired t tests and the χ² test were used to evaluate the clinical and radiological indicators.

RESULTS

No differences were found in the hospital stay, operation time, autologous blood recovery, postoperative drainage volume, Cobb angle of the preoperative coronal plane and sagittal plane, postoperative sagittal plane, postoperative Cobb angle of the coronal and sagittal planes measured on radiographs and computed tomography scans between the 2 groups (P > 0.05). The correction of the kyphosis deformity of the fracture segment was better in both groups (P < 0.001). The intraoperative blood loss and Cobb angle of the postoperative coronal plane in the NG was less than that in the CG (P < 0.05). Also, the 4 vertebral body screws in the NG were more parallel to the endplate than were those in the CG.

CONCLUSIONS

We found that the use of navigation can improve the accuracy of screw placement in anterior approach surgery for thoracolumbar burst fractures and improve patients' long-term prognosis.

Evolution of imaging in surgical fracture management

Intraoperative imaging has been advanced substantially over the last decades. It supports localization of the region of interest, verification of the preoperatively classified fracture pattern, identification of correct insertion point of the implant, placement of instruments and fixation material, and verification of correct fracture reduction and implant positioning. While conventional fluoroscopic 2D imaging remains the gold standard in intraoperative imaging, critical anatomical regions are predestined for intraoperative 3D imaging. Additional options such as perioperative virtual planning, simulation, and surgical training, 3D printing techniques and 3D augmented reality visualization may potentially open new windows to improve surgical results in fracture care. This manuscript presents an update on current and upcoming imaging techniques in orthopaedic and trauma surgery focusing on technical advances for decreasing malreduction, malalignment, and malposition, as well as tips and tricks for daily surgical practice in order to improve clinical outcomes and patients' and surgeons' safety.

[Intraoperative 3D imaging in spinal surgery]

BACKGROUND

Intraoperative imaging during spinal interventions has experienced significant developments over the last two decades. By the introduction of flat screen detectors, 3D imaging has been made possible and easier and by developing compact and mobile systems computed tomography can even be used in the operating theater.

OBJECTIVE

Presentation of modern intraoperative 3D imaging and navigation in spinal surgery.

MATERIAL AND METHODS

The techniques of intraoperative 3D imaging and navigation during spinal procedures are presented based on the currently available literature and own experiences at a German national spine and trauma center.

RESULTS

The use of flat panel detectors and the possibility of 3D visualization nowadays substantially facilitate the use of navigation and allow certain control of surgical results even during the intervention. Radiation exposure of the whole team in the operating theater can be significantly reduced by the new techniques.

CONCLUSION

The advantages of intraoperative 3D imaging with a clear improvement of visualization for spinal surgeons and the certain control of materials at the end of the operation are obvious. Even the use of navigation has been greatly simplified and can therefore lead to an even greater precision and less radiation exposure. There are even more sophisticated developments, such as operation suites and intraoperative computed tomography but these are initially reserved for selected centers.

Open Versus Arthroscopic Mosaicplasty of the Knee: A Cadaveric Assessment of Accuracy of Graft Placement Using Navigation

PURPOSE

The purpose of this study was to compare an open freehand mosaicplasty technique with an arthroscopic technique for the treatment of osteochondral lesions by measuring the instrument deviation, quantifying this deviation, and providing numerical information on the difference in the outcomes of these techniques.

METHODS

Four cadaveric knees were used. Reference markers were attached to the femur, tibia, and donor/recipient site guides. A total of 10 osteochondral grafts were harvested and inserted into recipient sites arthroscopically and 10 similar grafts were inserted freehand. The angles of graft removal and placement were calculated for each of the surgical groups compared. Ostensibly, a navigation system was used as an aid, to measure the graft placement parameters.

RESULTS

Statistical analysis revealed that there was no statistically significant difference between the arthroscopic method and the freehand method regarding the angle of graft removal at the donor site (P = .162), recipient site plug removal angle (P = .731), and recipient site graft placement angle (P = .630). In the freehand group, the mean angle of graft removal at the donor site was 12°, the mean angle of recipient site plug removal was 10.7°, and the mean angle of recipient site plug placement was 10.6°. Using the arthroscopic technique, the mean angle of graft removal at the donor site was 17.14°, the mean angle of recipient site plug removal was 12.0°, and the mean angle of recipient site graft placement was 10.14°.

CONCLUSIONS

Our study revealed there was no statistically significant difference regarding precision and accuracy during harvesting, recipient site preparation, and plug placement between the 2 techniques.

CLINICAL RELEVANCE

Controversy exists whether an open or arthroscopic osteoarticular transfer system (OATS) technique provides superior accuracy. According to our results, there is no statistically significant difference regarding better visualization, precision, and accuracy between the freehand and arthroscopic techniques. However, larger number of specimens are required for study.

Arthroscopic mosaicplasty for osteochondral lesions of the knee: computer-assisted navigation versus freehand technique

PURPOSE

The purpose of this study was to compare a freehand arthroscopic approach versus mosaicplasty for treatment of osteochondral lesions of the knee with a navigated arthroscopic technique.

METHODS

Four whole cadaveric lower limbs were used. A conventional navigation system was used in combination with an autologous osteochondral graft transplantation system (Osteochondral Autograft Transfer System [OATS]; Arthrex, Naples, FL). The congruity of the articular surface was measured with the navigation probe to detect any difference between the surface created by the grafts and the surface of the femoral condyle surrounding them. The angle relates to a line perpendicular to the articular surface. This line is made by the cutting instrument for graft harvesting and insertion and the articular surface.

RESULTS

The mean angle of graft harvest was 3.4° (range, 0° to 10°) in the navigated group versus 14.8° (range, 6° to 26°) in the freehand group (P < .0003). The mean angle for recipient-site coring was 1.5° (range, 0° to 5°) in the navigated group versus 12.6° (range, 4° to 17°) in the freehand group (P < .0003). The mean angle of graft placement was 2° (range, 1° to 5°) in the navigated group versus 10.8° (range, 5° to 15°) in the freehand group (P = .0002). The mean protrusion height of the plug was 0.23 mm (range, 0.1 to 0.5 mm; SD, 0.16) in the navigated group versus 0.34 mm (range, 0.0 to 0.7 mm; SD, 0.25) in the freehand group (P = .336).

CONCLUSIONS

Computer-assisted arthroscopic mosaicplasty for treatment of osteochondral lesions in the cadaveric model presented in this study allows permanent visualization of the angle of recipient-site preparation, the depth of the donor plug and the recipient plug, and the angle of insertion of the graft at the recipient site.

CLINICAL RELEVANCE

This study shows evidence of potentially greater precision and reproducibility of navigated arthroscopic mosaicplasty when compared with an arthroscopic freehand technique in a cadaveric model. However, true clinical outcome benefit will only be elucidated upon performance of appropriate clinical studies.

Freehand versus navigated glenoid anchor positioning in anterior labral repair

PURPOSE

Anchor placement on the glenoid rim is challenging with the angle of insertion critical to achieving satisfactory results. Incorrect anchor placement is a common problem.

METHODS

Three plastic shoulder models were used. Reference markers were attached in the posterior portion of the acromion. Using the navigation system, reference point data from the glenoid were acquired. An anterior labral lesion of the glenoid was created that extended from the 1 o'clock to the 5 o'clock position. Three suture anchors were placed under arthroscopic guidance without the aid of navigation system (Group A) and with the aid of navigation system (Group B). Deviation from the optimal angle of 45° for anchor placement was measured and compared between the two groups.

RESULTS

The mean insertion angles for anchor placement were 45.9° (SD 3.4°, 40.2°-50.4°) and 41.4° (SD 3.9°, 33.1°-47.6°) in the freehand (Group A) and navigated (Group B) groups, respectively. There was a statistically significant difference between the groups (P < 0.05). The mean deviation (from the optimal angle) was 4.2° (SD 3.2°, 0.0°-11.9°) and 2.8° (SD 2.2°, 0.2°-8.4°) in the freehand and navigated groups, respectively.

CONCLUSION

Navigation systems may improve the accuracy of glenoid anchor placement amongst low-volume shoulder surgeons. However, it does not provide any significant advantage over the freehand technique in a plastic shoulder model. Constant multiplanar visualization throughout anchor placement as facilitated by navigation made the procedure more manageable, even for an experienced surgeon.