Cadmore media player playing video 10.3171/2025.4.FOCVID255
Video Player
Accessibility
Using forms mode, you can utilize keyboard shortcuts to make usability more efficient.
Space bar will play and pause the video. Pressing escape will close all displays and pressing it again will jump to the end of the player.
You can press A to open the Keyboard Shortcut Dialog which also provides an audio description of the player and all of its features.
Language
1x
Play Speed
Adjust Volume
Transcript
Search
Result Count
of
Click to jump to result
Search
Re-center
Segments
Result Count
of
Click to jump to result
Search
Name:
10.3171/2025.4.FOCVID255
Description:
10.3171/2025.4.FOCVID255
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/fe3af856-9e5a-49bb-8bb6-e518a50e160b/videoscrubberimages/Scrubber_233.jpg
Duration:
T00H10M11S
Embed URL:
https://stream.cadmore.media/v10.3171/2025.4.FOCVID255
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/fe3af856-9e5a-49bb-8bb6-e518a50e160b/8. 25-5.mp4?sv=2019-02-02&sr=c&sig=hmcAH0khGLvZjG7qdT9u1pcM%2FHwobVYZ2aJUZG15UwY%3D&st=2026-04-05T03%3A09%3A33Z&se=2026-04-05T05%3A14%3A33Z&sp=r
Upload Date:
2025-05-28T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
SPEAKER: We will be going into the technical nuances of robot-assisted sacroiliac screws, which are used in lumbosacral fixation. These are also commonly known as S2 alar-iliac screws because of their entry points, and are a standard of practice in long fusions in the lumbar spine. In this video, we are using the Mazor X Stealth edition from Metronic, which is their third-generation robotic system, running software version 5.12. The patient is a 47-year-old lady, who had presented with complaints of pain in the lower back region, radiating to the bilateral lower limbs, along with progressive difficulty in walking.
SPEAKER: She also had complaints of sensory dysesthesias in the lower limbs along the L5–S1 dermatomal distribution. There was history of progressive neurogenic claudication. There were no complaints of altered bowel or bladder habits. On clinical examination, the bulk and tone were normal. Power was decreased in the lower limbs, with grade 4 across all muscle groups in the bilateral lower limbs. Sensory examination revealed a mild impairment to perception of light touch in the bilateral L5–S1 dermatomes.
SPEAKER: DTRs were decreased across the bilateral knee and ankle joints. X-ray of the lumbosacral spine in AP and lateral views showed a degenerative scoliosis of the lumbar spine, with convexity to the right and degenerative changes of the lumbosacral spine, while MRI showed multi-level disk prolapses and a grade 1 listhesis at the L3–4 and L4–5 levels, with varying degrees of foraminal stenosis in the lumbar spine.
SPEAKER: The patient was positioned prone on an Allen Advance table, with the arms abducted at the shoulder to 90 degrees and placed in padded arm supports alongside the head. The placement of S2AI screws involves minor modifications in the workflow, compared to thoracolumbar pedicle screw placement with robot assistance.
SPEAKER: Broadly, the steps are the usual scan and plan workflow, with the field of view set to 40 centimeters on the O-arm, followed by planning of screws in the ilium. verification of the trajectory using navigated instruments and planning software, positioning the robotic arm to the specified trajectory and, finally, insertion of the S2AI screws.
SPEAKER: Schanz's pin is inserted into the ilium, ensuring it does not interfere with the planned S2AI screws. It is checked for a sturdy hold, and the robot is physically mounted onto the patient using this Schanz's pin with the help of a bridge.
SPEAKER: The region of interest is then covered with a nonreflective sheet. A 3Define scan is performed to identify possible obstacles in the path of the robotic arm. While the 3Define scan is going on, the scrub nurse verifies the instruments by placing them over the reference frame divot. A snapshot of the robotic arm is then taken to register the navigation frame position relative to the arm.
SPEAKER: Region of interest is marked using a blunt passive planar probe, and the robotic arm is sent to the marked position. A star marker is attached to the robot's arm, and positioned as close to the patient's body as is possible to cover more segments. The O-arm is then brought in to perform an intraoperative CT, with the patient fully covered by a disposable plastic drape. All four beads of the star marker must be clearly visualized on the 3D scan.
SPEAKER: This can be ensured by taking orthogonal X-rays of the surgical area before the final spin. The key to covering a larger area is positioning the star marker close to the skin. During the O-arm scan, a 20-centimeter field of view, or FOV, is standard, and is typically used for placing cervical and thoracolumbar pedicle screws. A 40-centimeter FOV is used for S2AI screw insertion and iliosacral screw placement.
SPEAKER: It is crucial to ensure that both iliac wings are fully visible when acquiring a 40-centimeter FOV scan. After the O-arm scan, planning begins by marking the region of interest, roughly outlining the spinal canal in the area. The robot then provides probable segmentation, which is verified and labeled with reference to the sacral vertebrae. Once segmentation is complete, planning for the iliac screws starts.
SPEAKER: The screws are initially oriented roughly along the ilium in the sagittal, coronal, and axial planes. Adjustments are made while scrolling through the CT cuts, ensuring the screw trajectory avoids any breach in the bony cortices. Specific attention is given to the sciatic notch, iliac tables, and acetabulum. After planning the trajectory of the screws, the incision is checked using the software's skin-level feature, aiming to place both S2AI screws through a single midline incision.
SPEAKER: Once planning is finalized, the process proceeds to screw insertion. A common error at this stage is setting the region of interest too narrow on the robot console. If this happens, even if a wider image is acquired, the robot will only display the cropped image. During the planning phase, attention must be paid to the axial, coronal, and sagittal sections. In the coronal view, the S2AI screw should start at the midpoint between the S1 and S2 foramina, lateral to the foraminal border.
SPEAKER: The screws should be planned with 40 to 50 degrees of lateral angulation, and 20 to 30 degrees of caudal angulation, with a minimum length of 80 millimeters. The angle of entry at the iliac surface of the SI joint influences the risk of skiving with more obtuse angles, posing a greater risk. This clip shows the insertion of the left iliac screw. For percutaneous S2AI screw insertion, the skin is first incised twice in opposite directions, so as to comfortably fit the robotic instruments without being subjected to traction by soft tissue, fascia, or the muscles.
SPEAKER: After positioning the robotic arm to the planned trajectory, a sleeve with a trocar is then placed. And once it sits on the bone, a pilot hole is created using a high-speed drill. Since the pilot hole may not cross the SI joint, a 4-millimeter tap is passed to extend it beyond the joint. This is followed by tapping with a 6.5-millimeter tap. And finally, the iliac screw is inserted to the desired depth under navigation guidance.
SPEAKER: The same steps are followed for inserting the right-side screw. This workflow allows surgeons to place S2AI screws percutaneously, minimizing the need for extensive exposure and blood loss. Additionally, it eliminates extra radiation exposure to surgeons, staff, and patients, unlike fluoroscopy-guided sacroiliac screws. The non-availability of a longer 3-millimeter high-speed drill bit is a challenge that needs to be addressed.
SPEAKER: Our workflow was designed using the available instruments. The 4.0-millimeter awl-tipped tap is sharp, which helps prevent skiving and allows it to cross the SI joint with a lower risk of maltracking. In most cases, the planning closely matches the execution.
SPEAKER: Let's reiterate the steps for S2AI screw fixation. Drill a pilot hole using a 3.0-millimeter drill bit through the sleeve and arm guide. Tap with the 4.0-millimeter awl-tipped tap, which is a critical step for maintaining the trajectory to a depth of 60 millimeters. Tap with the 6.5-millimeter tap to ensure the entire length of the trajectory is prepared. Insert the 7.5- or 8.5-millimeter S2AI screw using power tools to minimize maltracking. Verify the final position using fluoroscopy.
SPEAKER: One of our patient's postoperative CT is shown here, demonstrating perfect placement of S2AI screws with no breaches. Postoperative 3D CT shows proper placement of implants. The robot also facilitates the planning and placement of S1 alar-iliac screws, which can be used alongside S2 iliac screws for enhanced spinopelvic stabilization. The starting point for the S1 alar-iliac screws is just lateral to the junction of the S1 superior articular facet, and the posterior sacral ala, which is in proximity to the entry point for S1 pedicle screws.
SPEAKER: It is 3 to 5 millimeters above the superolateral corner of the S1 foramen. The double screws may help in achieving greater spinopelvic stability. Few advantages of S2AI iliac screws over iliac screws or bolts, are that it is associated with lesser risk of complications, such as screw prominence, gluteal pain, and wound breakdown, primarily because of iliac bolts' superficial PSIS entry point.
SPEAKER: Compared with freehand insertion, robotic insertion of S2AI screws has multiple advantages, such as avoidance of screw misplacement, breach of cortical bone, and injury to neurovascular structures, which are more often seen in manual insertion. While opting for the scan and plan workflow on Mazor X system, there is no need of a preoperative CT scan, as this additional scan would expose the patient to unnecessary radiation, and there might be a discordance between the intraoperative positioning and the positioning obtained during the preoperative CT imaging.
SPEAKER: For these reasons, we opt for an intraop-obtained scan and plan workflow. Another important point to note is that while using the drills, one has to drill intermittently, while appreciating the haptic feedback at the tip of the screw every time before restarting. This can help in minimizing lateral breach.
Segment:0 .
SPEAKER: We will be going into the technical nuances of robot-assisted sacroiliac screws, which are used in lumbosacral fixation. These are also commonly known as S2 alar-iliac screws because of their entry points, and are a standard of practice in long fusions in the lumbar spine. In this video, we are using the Mazor X Stealth edition from Metronic, which is their third-generation robotic system, running software version 5.12. The patient is a 47-year-old lady, who had presented with complaints of pain in the lower back region, radiating to the bilateral lower limbs, along with progressive difficulty in walking.
SPEAKER: She also had complaints of sensory dysesthesias in the lower limbs along the L5–S1 dermatomal distribution. There was history of progressive neurogenic claudication. There were no complaints of altered bowel or bladder habits. On clinical examination, the bulk and tone were normal. Power was decreased in the lower limbs, with grade 4 across all muscle groups in the bilateral lower limbs. Sensory examination revealed a mild impairment to perception of light touch in the bilateral L5–S1 dermatomes.
SPEAKER: DTRs were decreased across the bilateral knee and ankle joints. X-ray of the lumbosacral spine in AP and lateral views showed a degenerative scoliosis of the lumbar spine, with convexity to the right and degenerative changes of the lumbosacral spine, while MRI showed multi-level disk prolapses and a grade 1 listhesis at the L3–4 and L4–5 levels, with varying degrees of foraminal stenosis in the lumbar spine.
SPEAKER: The patient was positioned prone on an Allen Advance table, with the arms abducted at the shoulder to 90 degrees and placed in padded arm supports alongside the head. The placement of S2AI screws involves minor modifications in the workflow, compared to thoracolumbar pedicle screw placement with robot assistance.
SPEAKER: Broadly, the steps are the usual scan and plan workflow, with the field of view set to 40 centimeters on the O-arm, followed by planning of screws in the ilium. verification of the trajectory using navigated instruments and planning software, positioning the robotic arm to the specified trajectory and, finally, insertion of the S2AI screws.
SPEAKER: Schanz's pin is inserted into the ilium, ensuring it does not interfere with the planned S2AI screws. It is checked for a sturdy hold, and the robot is physically mounted onto the patient using this Schanz's pin with the help of a bridge.
SPEAKER: The region of interest is then covered with a nonreflective sheet. A 3Define scan is performed to identify possible obstacles in the path of the robotic arm. While the 3Define scan is going on, the scrub nurse verifies the instruments by placing them over the reference frame divot. A snapshot of the robotic arm is then taken to register the navigation frame position relative to the arm.
SPEAKER: Region of interest is marked using a blunt passive planar probe, and the robotic arm is sent to the marked position. A star marker is attached to the robot's arm, and positioned as close to the patient's body as is possible to cover more segments. The O-arm is then brought in to perform an intraoperative CT, with the patient fully covered by a disposable plastic drape. All four beads of the star marker must be clearly visualized on the 3D scan.
SPEAKER: This can be ensured by taking orthogonal X-rays of the surgical area before the final spin. The key to covering a larger area is positioning the star marker close to the skin. During the O-arm scan, a 20-centimeter field of view, or FOV, is standard, and is typically used for placing cervical and thoracolumbar pedicle screws. A 40-centimeter FOV is used for S2AI screw insertion and iliosacral screw placement.
SPEAKER: It is crucial to ensure that both iliac wings are fully visible when acquiring a 40-centimeter FOV scan. After the O-arm scan, planning begins by marking the region of interest, roughly outlining the spinal canal in the area. The robot then provides probable segmentation, which is verified and labeled with reference to the sacral vertebrae. Once segmentation is complete, planning for the iliac screws starts.
SPEAKER: The screws are initially oriented roughly along the ilium in the sagittal, coronal, and axial planes. Adjustments are made while scrolling through the CT cuts, ensuring the screw trajectory avoids any breach in the bony cortices. Specific attention is given to the sciatic notch, iliac tables, and acetabulum. After planning the trajectory of the screws, the incision is checked using the software's skin-level feature, aiming to place both S2AI screws through a single midline incision.
SPEAKER: Once planning is finalized, the process proceeds to screw insertion. A common error at this stage is setting the region of interest too narrow on the robot console. If this happens, even if a wider image is acquired, the robot will only display the cropped image. During the planning phase, attention must be paid to the axial, coronal, and sagittal sections. In the coronal view, the S2AI screw should start at the midpoint between the S1 and S2 foramina, lateral to the foraminal border.
SPEAKER: The screws should be planned with 40 to 50 degrees of lateral angulation, and 20 to 30 degrees of caudal angulation, with a minimum length of 80 millimeters. The angle of entry at the iliac surface of the SI joint influences the risk of skiving with more obtuse angles, posing a greater risk. This clip shows the insertion of the left iliac screw. For percutaneous S2AI screw insertion, the skin is first incised twice in opposite directions, so as to comfortably fit the robotic instruments without being subjected to traction by soft tissue, fascia, or the muscles.
SPEAKER: After positioning the robotic arm to the planned trajectory, a sleeve with a trocar is then placed. And once it sits on the bone, a pilot hole is created using a high-speed drill. Since the pilot hole may not cross the SI joint, a 4-millimeter tap is passed to extend it beyond the joint. This is followed by tapping with a 6.5-millimeter tap. And finally, the iliac screw is inserted to the desired depth under navigation guidance.
SPEAKER: The same steps are followed for inserting the right-side screw. This workflow allows surgeons to place S2AI screws percutaneously, minimizing the need for extensive exposure and blood loss. Additionally, it eliminates extra radiation exposure to surgeons, staff, and patients, unlike fluoroscopy-guided sacroiliac screws. The non-availability of a longer 3-millimeter high-speed drill bit is a challenge that needs to be addressed.
SPEAKER: Our workflow was designed using the available instruments. The 4.0-millimeter awl-tipped tap is sharp, which helps prevent skiving and allows it to cross the SI joint with a lower risk of maltracking. In most cases, the planning closely matches the execution.
SPEAKER: Let's reiterate the steps for S2AI screw fixation. Drill a pilot hole using a 3.0-millimeter drill bit through the sleeve and arm guide. Tap with the 4.0-millimeter awl-tipped tap, which is a critical step for maintaining the trajectory to a depth of 60 millimeters. Tap with the 6.5-millimeter tap to ensure the entire length of the trajectory is prepared. Insert the 7.5- or 8.5-millimeter S2AI screw using power tools to minimize maltracking. Verify the final position using fluoroscopy.
SPEAKER: One of our patient's postoperative CT is shown here, demonstrating perfect placement of S2AI screws with no breaches. Postoperative 3D CT shows proper placement of implants. The robot also facilitates the planning and placement of S1 alar-iliac screws, which can be used alongside S2 iliac screws for enhanced spinopelvic stabilization. The starting point for the S1 alar-iliac screws is just lateral to the junction of the S1 superior articular facet, and the posterior sacral ala, which is in proximity to the entry point for S1 pedicle screws.
SPEAKER: It is 3 to 5 millimeters above the superolateral corner of the S1 foramen. The double screws may help in achieving greater spinopelvic stability. Few advantages of S2AI iliac screws over iliac screws or bolts, are that it is associated with lesser risk of complications, such as screw prominence, gluteal pain, and wound breakdown, primarily because of iliac bolts' superficial PSIS entry point.
SPEAKER: Compared with freehand insertion, robotic insertion of S2AI screws has multiple advantages, such as avoidance of screw misplacement, breach of cortical bone, and injury to neurovascular structures, which are more often seen in manual insertion. While opting for the scan and plan workflow on Mazor X system, there is no need of a preoperative CT scan, as this additional scan would expose the patient to unnecessary radiation, and there might be a discordance between the intraoperative positioning and the positioning obtained during the preoperative CT imaging.
SPEAKER: For these reasons, we opt for an intraop-obtained scan and plan workflow. Another important point to note is that while using the drills, one has to drill intermittently, while appreciating the haptic feedback at the tip of the screw every time before restarting. This can help in minimizing lateral breach.
Form Title Download
Transcript
Form Title Bookmark
Entire Media
Segment(s)
Custom Clip
Start At:
End At:
Form Title Share
Entire Media
Segment(s)
Custom Clip
Start At:
End At:
Form Title Accessibility and Keyboard Shortcuts
The cadmore media player is a professional video and audio player experience designed to deliver media as well as relevant transcript, segmentation, and metadata. On the screen is a traditional html video player with buttons such as play, pause, forward, captioning, language and play speed selection and more. Adjacent to the video player are generally tabs, one of which shows a scrolling transcript of the video and the other shows any segmentation of the media, sometimes referred to as chapters. At the top of the video is a menu bar containing an Explore button and Tools button. The Explore button allows you to dig deeper into the video by opening up an explore dialog which contains tabs for a visual navigation of the video using thumbnails, an about tab which contains rich metadata about the media, a segments tab which contains further information about the video, and a related tab which contains links to other media related to this media. The tools button opens a menu with options for sharing the media on social media, creating bookmarking links, creating embed codes for your website, generating citations, and more.
Keyboard Shortcuts
Keyboard shortcuts only work while you are in forms mode. By entering forms mode, you will be able to quickly access portions of the media player with single key commands.
Spacebar: Play/Pause Toggle
I: Info Menu,
O: Tools Menu
T: Transcript Tab,
S: Segments Tab
F: Forward 15,
R: Rewind 15
L: Languages,
P: Playspeed
M: Mute Toggle,
V: Volume Bar
N: Video Only Toggle,
B: Full Screen Toggle
C: Captions Toggle
Escape: Closes dialogs and menus / Exits Player
Z: Next Transcript Chapter
X: Previous Transcript Chapter
Q: Next Transcript Paragraph
W: Previous Transcript Paragraph
Entire Media
Segment(s)
Custom Clip
Start At:
End At:
Embed Size
-
You Size - Responsive
-
We Size - Responsive
-
Picture Overlay Popup
-
400 x 225
-
512 x 288
-
400 x 700
-
768 x 1024
-
1024 x 512
-
1280 x 608
Form Title Cite
No citation provided.
Info
Segments
Related
Thumbnails
Exit Clip Mode
You have requested to see a portion of the video outside of the clip.
Click OK to switch to the full video or click if you would like to stay inside the clip. You can always go back to the clip with Tools and Clip Mode