Day 4 Flashcards
The Synfix implant is biomechanically equivalent to what?
A spacer with pedicle screws
Is the height on Synfix determined by the plate or spacer itself?
PEEK Spacer, including teeth - not the plate
Does the height of the Synfix implant include the pyramidal teeth?
Yes.
Is the screw measurement for Synfix an “overall height” or “working length?”
Overall height
With Synfix, what does “zero profile construct” mean?
Spacer and plate sit completely within the disc space
Synfix LR. “LR” stands for?
Lumbar Radiolucent
How many options are there for inserting the Synfix implant?
Three
- SQUID
- Implant Holder + Distractor
- Aiming Device
What is the thread description of the Synfix locking screws?
Double-Lead
What material is the plate in made out of in Synfix?
Titanium
What are the 2 Types of Synfix screws?
- Self-Tapping
2. Fine Tip
Why is the Synfix implant convex?
To match the anatomy of the disc space
Synfix Features / Benefits
- Stand alone ALIF
- One approach (anterior)
- Zero-profile
- Implant fits entirely in the disc space
- Anatomic shape with CONVEX ENDPLATES
- improved INTERFACE with VERTEBRAL bodies
- Screw and plate fixation w/conical locking screws
- Equivalent to pedicle screw fixation
Approved Indications for Prodisc
- DDD
- Single level disease
- L3-S1
- No more than grade 1 spondy
- No osteopenia no osteoporosis
- Failure of 6 months of conservative treatments
Synfix creates a wedge of _______ for fixation.
Bone
Synfix screw placement technique
- Awl
- 1st Screw
- Awl
- 2nd Screw
- ROTATE AIMING DEVICE
- Awl
- 3rd Screw
- Awl
- Insert 4th Screw
Synfix PEEK spacer provides a modulus of elasticity similar to _______
Cortical Bone
Ideal patient for ProDisc is
- Single level
- Thin, fit
- Highly motivated to get better
- Maximally rehabilitated w/ conservative care
- No narcotics
- Not poor or crazy (psychological issues)
Synfix Quick Surgical Technique
- Approach
- Diskectomy
- Trial
- Select and Prepare Implant
- Insert Implant
- Screw Hole Preparation
- Insert & FINAL TIGHTEN your screw
- Insert & FINAL TIGHTEN your screw
- Insert & FINAL TIGHTEN your screw
- Insert & FINAL TIGHTEN your screw
With Prodisc, we would use lateral bending films to determine
Whether there is a Spondylosisthesis because pars fx’s are contraindicated
Concordant Response
When location of the injection of dye corresponds with where patient feeling pain.
Discordant Response
When location of the injection of dye DOES NOT correspond with where patient feeling pain.
4 Critical Steps of instrumenting Prodisc
- Disc space prep
- Remobilization of the space
- Positioning of instruments at midline
- Sizing of / for implant
Prodisc Technique Summary
- Anterior Access
- Diskectomy and Remobilization
- Implantation
What’s the MOST important step in the ProDisc Technique?
Remobilization and Diskectomy
-ProDisc will not create motion - it only MAINTAINS the motion the SURGEON creates!
What part of the technique takes the longest time?
Diskectomy and Remobilization
What is the height of the keel in ProDisc-L?
6.5mm
What are we looking for on xray with candidates for Prodisc?
- Straight alignment in AP
- Normal sagittal alignment
- Disc space
- Spondylosisthesis
- Sacral angle … To name a few (page 1, section 3)
One of the 1st things you should determine when starting the implant procedure?
Midline of vertebral bodies on AP floro
Height of closed spreader
6mm
Initial purpose of the spreader is to _______
Mobilize the disc space
What is optimal position of the spreader?
Parallel to endplates and tips of spreaders MUST be on edge of both posterior vertebrae
Issues caused by poorly placed spreader?
It can breach the endplate
What are pros and cons of removing posterior osteophytes?
PROs
- Helps with mobilizing the vertebrae
- easier posterior placement of device
- reduced risk of osteophyte breaking off and migrating into canal
CONS
- more bleeding bed (encourages fusion -which we don’t want)
- increased subsidence
Mantra for sizing
- Smallest Height
2. Biggest Footprint
How much remobilization is enough?
- Adjacent Levels
- Surgeon tactile feedback/feel
General sizing guidelines
Women, smaller men
°Start with 10 - 6
Larger men
°Start w/ L -10, 6
Reasons why trial won’t go midline?
- Osteophytes
- Imbalanced remobilization
- Asymmetrical anatomy
Can the implant chisel a new pathway if chisel wasn’t driven far (posteriorly) enough initially?
No.
2 lordotic angulations in Prodisc
6°
11°
3 heights for Prodisc L
- 10
- 12
- 14
3 Mantras for Prodisc L
- “Dome Up” (Poly)
- “I see daylight” (Inserter)
- “No step - no gap” (Poly w/ endplates)
Why would the doctor hold a long metal instrument at the patient’s side and then take a pic using floro when preparing for his approach-/do section?
Because it ensures that the incision and exposure will allow direct visualization into the disc space. (Not too cranial - no too caudal with incision
What is the surgical approach for Synfix?
Retroperitoneal
A mini-open retroperitoneal approach can be used with the SYNFIX Mini-open Instruments.
10 in anterolateral approach be used or a lateral approach used for Synfix?
No. Direct anterior approach only.
Why is a direct anterior approach important with Synfix?
To ensure that the locking screws are seated correctly.
How much disc space is needed (in the coronal plane) to seat the implant?
Doc should expose the disc segment to produce sufficient space on either side of the vertebral midline, equal to half the width of the implant. This allows insertion of the implant, without interference from adjacent soft tissue structures.
Is it adequate to see “almost all” of the spacer after seating it in the disc space? Why or why not?
When the spacer has been inserted, visualization
of the entire anterior plate is necessary for insertion of the locking screws.
What is a “Tip” than can help to make sure your annular window is wide enough for Synfix during your annulotomy?
Hold a trial spacer up to the vertebral disc as a template for the width - then make your annulotomy.
Synfix trials are color-coded according to what?
Height
What to lordotic angles are available for Synfix
8° and 12°
What are Synfix’s 2 depth (A-to-P) options?
26mm
30mm
What are Synfix’s 2 widths?
32mm
38mm
What are Synfix’s 4 types of measurements?
- Depth (26mm 30mm)
- Width (32mm, 38mm)
- Lordotic Angle (8°, 12°)
- Height (12, 13.5, 15, 17, 19mm)
Which 2 Synfix heights can use the same drill guide/attachment?
13.5mm and 15mm
What do laser etchings on the anterior edge of the trial spacers indicate?
They indicate locking screw entry point in the anterior aspect of the adjacent level vertebrae.
What 2 size options (not including height or angle) does Synfix offer?
26mm (deep) x 32mm (wide)
30mm (deep) x 38mm (wide)
Should we select minimum or maximum size and point for Synfix?
Select the maximum sized implant to give you greatest surface area - which gives you better stability.
What information can you find on the packaging of the Synfix implant?
- Expiration dates
- Footprint
- Lordotic Angle
- Height
How does the color-coding work for the Synfix system?
Color-coding is based off height
What items are color-coded in Synfix?
- Aiming-guide handles
- Aiming-guide attachments
- Trial Spacers
- Titanium Alloy plates w/in the implant
What instrument that comes in the Synfix tray will help with the anterior approach/access?
Curved Handheld Retractor
How do you use the arrows on the Mini-Inserter Aiming Device?
The arrows on the Aiming Device should always be oriented/facing CRANIALLY and CAUDALLY. If they are, the aiming Device is oriented correctly.
How do you correctly orient the Synfix Detachable Aiming Device?
The flat surfaces of the detachable aiming device should be facing cranially and caudally.
How far down does the Angled Awl penetrate into bone when placed through the Synfix Aiming Device?
Approximately 10mm. The equivalent to the purchase length of a 15mm screw.
Why should you seat and final tighten each screw one-at-a time?
To maintain the position of the implant. If placing a second, or third screw before locking the implant into position, the implant could re-orient and move the out of its proper position.
What is the longest screw length the Synfix Mini Open instruments can accommodate?
25mm.
How do you know when your Synfix screw is “down?”
When the laser etching or “ring” meets the entry point of the aiming device, the screw is locked to the plate and should not be advanced further.
Can the Synfix Mini Open Attached, Aiming Device be rotated in either direction?
Yes. Keeping in mind to orient the arrows on the handle cranially and caudally.
Should you add, subtract, or keep the same, the measurement of the prepared screw hole - when selecting a screw?
The screws are organized by overall length. To get the “WORKING LENGTH” or “THREAD LENGTH,” you must subtract 5mm from the screw’s stated length.
