Angulation error assessment for the trajectory in the anteroposterior and lateral fluoroscopic views during percutaneous endoscopic transforaminal lumbar discectomy

BACKGROUND

Anteroposterior (AP) and lateral fluoroscopies are often used to evaluate the intraoperative location and angulation of the trajectory in percutaneous endoscopic transforaminal lumbar discectomy (PETLD). Although the location of the trajectory shown in fluoroscopy is absolutely accurate, the angulation is not always reliable. This study aimed to evaluate the accuracy of the angle shown in the AP and lateral fluoroscopic views.

METHODS

A technical study was performed to assess the angulation errors of PETLD trajectories shown in AP and lateral fluoroscopic views. After reconstructing a lumbar CT image, a virtual trajectory was placed into the intervertebral foramen with gradient-changing coronal angulations of the cephalad angle plane (CACAP). For each angulation, virtual AP and lateral fluoroscopies were taken, and the cephalad angles (CA) of the trajectory shown in the AP and lateral fluoroscopic views, which indicated the coronal CA and the sagittal CA, respectively, were measured. The angular relationships among the real CA, CACAP, coronal CA, and sagittal CA were further demonstrated with formulae.

RESULTS

In PETLD, the coronal CA is approximately equal to the real CA, with a small angle difference and percentage error, whereas the sagittal CA shows a rather large angle difference and percentage error.

CONCLUSION

The AP view is more reliable than the lateral view in determining the CA of the PETLD trajectory.

The usefulness of vertebral needle targeting simulation training system using ray-summation imaging: experimental study

PURPOSE

Using the multi-detector computed tomography and related three-dimensional imaging technology, we developed a vertebral needle targeting simulation training system named spinal needling intervention practice using ray-summation imaging (SNIPURS). Herein, we assessed the utility of SNIPURS by evaluating changes in the learning curves of SNIPURS trainees.

METHODS

Twenty-one examinees were enrolled: seven experienced operators (expert group), seven trainees with coaching (coaching group), and seven trainees without coaching (non-coaching group). They performed six tests of vertebral needle targeting simulation on the workstation-generated spinal ray-summation images of six patients with vertebral fractures. In each test, they determined the bilateral trans-pedicular puncture points and angles on two thoracic and two lumbar vertebrae on ray-summation imaging (i.e., 8 simulations per test). The coaching group received coaching by a trainer after Tests 1 and 4, while the others did not. Scores were given based on the trans-pedicular pathway (1 point) or not (0 point). Eight virtual needles were evaluated in each of Tests 1-6.

RESULTS

Among the three groups, the expert group had the highest average scores on Tests 1-4 (expert: 3.86, 6.57, 7.43, and 7.57; coaching: 1.86, 6.14, 6, and 6.29; and non-coaching: 1.14, 4.14, 4.71, and 4.86). The coaching group's scores caught up with the expert groups' average scores on Tests 5 and 6, whereas those of the non-coaching group did not (expert and coaching: 7.86 and 8.00, non-coaching: 5.86 and 7.14). All examinees in the expert and coaching groups achieved a perfect score on the final Test 6, whereas three of the seven non-coaching trainees did not.

CONCLUSION

SNIPURS might be suitable for vertebral needle targeting training. The coaching provided during SNIPURS training helped the trainees to acquire the spinal puncture techniques in PVP.

The effect of artificial X-rays on C-arm positioning performance in a simulated orthopaedic surgical setting

PURPOSE

We designed an Artificial X-ray Imaging System (AXIS) that generates simulated fluoroscopic X-ray images on the fly and assessed its utility in improving C-arm positioning performance by C-arm users with little or no C-arm experience.

METHODS

The AXIS system was comprised of an optical tracking system to monitor C-arm movement, a manikin, a reference CT volume registered to the manikin, and a Digitally Reconstructed Radiograph algorithm to generate live simulated fluoroscopic images. A user study was conducted with 30 participants who had little or no C-arm experience. Each participant carried out four tasks using a real C-arm: an introduction session, an AXIS-guided set of pelvic imaging tasks, a non-AXIS guided set of pelvic imaging tasks, and a questionnaire. For each imaging task, the participant replicated a set of three target X-ray images by taking real radiographs of a manikin with a C-arm. The number of X-rays required, task time, and C-arm positioning accuracy were recorded.

RESULTS

We found a significant 53% decrease in the number of X-rays used and a moderate 10-26% improvement in lateral C-arm axis positioning accuracy without requiring more time to complete the tasks when the participants were guided by artificial X-rays. The questionnaires showed that the participants felt significantly more confident in their C-arm positioning ability when they were guided by AXIS. They rated the usefulness of AXIS as very good to excellent, and the realism and accuracy of AXIS as good to very good.

CONCLUSION

Novice users working with a C-arm machine supplemented with the ability to generate simulated X-ray images could successfully accomplish positioning tasks in a simulated surgical setting using markedly fewer X-ray images than when unassisted. In future work, we plan to determine whether such a system can produce similar results in the live operating room without lengthening surgical procedures.

The Usefulness of Virtual Fluoroscopic Preprocedural Planning During Percutaneous Transhepatic Biliary Drainage

PURPOSE

To retrospectively evaluate the usefulness of virtual fluoroscopic preprocedural planning (VFPP) in the percutaneous transhepatic biliary drainage (PTBD) procedure.

MATERIALS AND METHODS

Twenty-two patients who were treated by PTBD were included in this study. Twelve patients were treated using PTBD intraoperative referencing coronal computed tomography (CT) images (i.e., coronal CT group), and ten patients were treated using PTBD intraoperative referencing VFPP images (i.e., VFPP group). To analyze the effect of the intraoperative referencing VFPP image, the VFPP group was retrospectively compared with the coronal CT group.

RESULTS

The characteristics of both patient groups were not statistically significantly different. There were no significant differences in the targeted bile duct, diameter and depth of the target bile, breath-holding ability, number of targeted bile duct puncture attempts, change in the targeted bile duct, and exchange of the drainage catheter. However, the X-ray fluoroscopy time and the procedure time were significantly shorter in the VFPP group than in the coronal CT group (196 vs. 334 s, P < 0.05; and 16.0 vs. 27.2 min, P < 0.05).

CONCLUSION

Intraoperative referencing using the VFPP imaging in PTBD intuitively can be a useful tool for better localization of the guidewire in the bile duct and thereby shorten the X-ray fluoroscopy time and procedure time while minimizing radiation exposure and complications.