What is Augmented Reality (AR)?

Augmented reality is a technology that superimposes a computer generated image onto a users view of the real world.

How is AR different from a surgeon using just navigation or robotics?

The key advantage of AR is that it allows the surgeon to not have to take his/her eyes off of the patient/surgical field and look directly through the headset whereas when surgeons use navigation or robotics, they have to look away from the patient and at a monitor to perform the surgery.

How are spine surgeons using AR in surgery?

Surgeons are using AR to improve the accuracy and precision of spinal instrumentation placed into the spine, thereby improving patient outcomes.

When using AR, spine surgeons wear a headset. This headset will provide computer generated images of the patients CT scan into their eyepieces which will display surgical anatomy and imaging that is superimposed over the users view of the real world. This is similar to GPS navigation in your car in which it displays computer-based surgical navigation guidance info onto the surgeons visual field thereby increasing the safety and accuracy of surgery. This allows for visualization of deep structures without the need to make an incision therefore giving the surgeon essentially, “x-ray vision.”

When compared to the more traditional open surgery done with really long incisions, minimally invasive spine surgery approaches can be faster, safer, and require less recovery time. Many times, the surgery can be done using incisions several millimeters or less.

Because of the reduced damage to the muscles and soft tissues during surgery, surgeries performed with MIS techniques can:

1. Have better cosmetic results because the incisions are smaller
2. Less scar tissue
3. Less blood loss
4. Less time under anesthesia
5. Reduced risk of muscle damage (since no cutting of the muscle is done and instead the muscle is moved to the side).
6. Faster recovery
7. Less rehabilitation is required

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Frequently Asked Questions

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What conditions are generally treated in a minimally invasive manner?

There are a number of various conditions that can be treated via a MIS approach including:

1. Degenerative disease disease
2. Herniated discs
3. Sacroiliac (SI joint) Dysfunction
4. Vertebral compression fractures
5. Lumbar spinal stenosis
6. Lumbar spondylithesis

How does Minimally Invasive Surgery work?

Traditionally, surgeons used very long incisions to perform spine surgery requiring patients to stay in the hospital for days to weeks after surgery. Patients who underwent these surgeries were at risk for postoperative complications including infection, prolonged hospital stays, increased bleeding, increased risk of blood clots, and more pain following surgery. With advancing technology and techniques, we are able to perform surgery in the most minimally invasive fashion using very small incisions and therefore less muscle and soft tissue damage. Therefore, patients generally leave the hospital sooner, have less blood loss, and recover quicker.

What are some of the common procedures treated with minimally invasive techniques?

Disc herniations: If you are a candidate, Dr. Webb can perform your surgery through a small tube and very small incision. This procedure, generally done through a 22mm tube, is also called a MITR (minimally invasive tubular retraction). This surgery involves progressive dilation of your soft tissues as opposed to cutting them. By using the tubes to move the muscles out of the way, Dr. Webb is able to work through a small incision without having to expose an entire part of your spine. Once the surgery is complete, the tubular retractor is removed, allowing the dilated tissues and muscles to fall back into place. By using the tubes to perform your surgery in this minimally invasive fashion, your recovery is quicker, you may need less pain meds after surgery, your infection risk is less, and you will be able to get back to doing some of the things that you enjoy doing quicker.

Lumbar Spinal Stenosis: If you are a candidate, Dr. Webb may sometimes perform your decompression surgery through a small tube via a very small incision. This procedure, generally done through a 22mm tube, is also called a MITR (minimally invasive tubular retraction). This surgery involves progressive dilation of your soft tissues as opposed to cutting them. By using the tubes to move the muscles out of the way, Dr. Webb is able to work through a small incision without having to expose the area widely. Once the surgery is complete, the tubular retractor is removed, allowing the dilated tissues and muscles to fall back into place. By using the tubes to perform your surgery in this minimally invasive fashion, your recovery is quicker, you may require less pain meds after surgery, your infection risk is less, and you will be able to get back to doing some of the things that you enjoy doing quicker.

Posterior Lumbar fusions: If you are a candidate, Dr. Webb may be able to perform your lumbar fusion through very small incisions on your lower back. Through these small incisions, Dr Webb will perform percutaneous placement  of percutaneous screws and rods that will help fuse and stabilize your spine. Percutaneous (meaning through the skin) placement of the screws and rods is done with x-ray guidance to ensure accuracy and precision of insertion. Traditionally, the incisions for lumbar fusions required extensive dissection of muscle and soft tissue in order to complete the surgery. Using minimally invasive techniques, patients generally recover quicker, have shorter hospital stays, less blood loss, and ultimately return to their activities sooner.

Lateral Lumbar fusions: If you are a candidate for this procedure, Dr. Webb may be able to perform your lateral lumbar fusion through a very small incision on the side of your abdomen. After the diseased disc is removed, Dr. Webb will then insert a metal or plastic cage filled with bone graft into this area. This procedure may also involve turning you prone (after Dr. Webb is done with the lateral part of your surgery) and then placement of percutaneous screws and rods that will help fuse and stabilize your spine. Percutaneous (meaning through the skin) placement of the screws and rods is done with x-ray guidance to ensure accuracy and precision of insertion. Traditionally, the incisions for lumbar fusions required extensive dissection of muscle and soft tissue in order to complete the surgery. Using minimally invasive techniques, patients generally recover quicker, have shorter hospital stays, less blood loss, and ultimately return to their activities sooner.

Sacroiliac (SI) Joint Fusion: If the SI joint is the cause of your low back pain, you may be a candidate for a minimally invasive SI joint fusion. This is usually an outpatient procedure that involves carefully placing metal screws across the SI joint, so the bones fuse and grow together. Fusing the joint helps to alleviate the pain associated with excess movement. This procedure is generally done through a very small incision and patients usually go home the same day of surgery.

If you are experiencing chronic back or leg pain that is unresponsive to conservative treatments, then you may be a candidate for minimally invasive spine surgery in conjunction with our computer 3D guided spinal navigation system.

How It Works

Surgical imaging and navigation technologies enable Dr. Webb to perform your surgery with accuracy and enhanced visualization both before and during surgery. Dr. Webb uses a planning computer software to help him prepare for your surgery, before you even arrive in the operating room. This plan is used to provide the pathway or route to accurately place the pedicle screws and other hardware on the day of surgery. By doing this, Dr. Webb will ensure the correct size implants and screws will be available the day of your surgery and also takes the guesswork out of performing your implantation. This not only saves time in surgery (meaning a shorter surgery), but also decreases complications of misplaced screws.

Most commercially available surgical navigation systems are based on infrared cameras detecting reflective spheres attached to the spine of the patient via a dynamic reference frame.

During surgery, Intraoperative images will provide a detailed 3D view of your specific anatomy in real time. Using computer guided navigation allows Dr Webb to display the surgical instruments and implants on a computer screen for Dr. Webb and the rest of the operating room staff to monitor throughout the case. This display gives Dr. Webb a real time view during the procedure for more precise implant placement.

Compared to traditional surgical techniques, computer-assisted navigation using intraoperative 3D imaging has been shown to improve screw placement accuracy and reduce complications due to screw misplacements. Moreover, improved accuracy has also been shown in more challenging conditions, such as scoliosis surgery, where it may be of even greater importance. Consequently, navigation also reduces the frequency of postoperative revision surgery compared to the more traditional surgery and minimizes radiation exposure to the surgeon, patient, and operating room staff.

It is important to understand that the decision to receive minimally invasive spinal navigation surgery is individualized to each patient and their symptoms. Dr. Webb will discuss whether you are a candidate for this procedure at your visit.

References

Tian, N. F. et al. Pedicle screw insertion accuracy with different assisted methods: a systematic review and meta-analysis of comparative studies. Eur Spine J. 20(6), 846–859 (2011).

Jin, M. et al. Incidence and risk factors for the misplacement of pedicle screws in scoliosis surgery assisted by O-arm navigation-analysis of a large series of one thousand, one hundred and forty five screws. Int Orthop. 41, 773–780 (2017).

Fichtner, J. et al. Revision rate of misplaced pedicle screws of the thoracolumbar spine-comparison of three-dimensional fluoroscopy navigation with freehand placement: a systematic analysis and review of the literature. World Neurosurg. 109, e24–e32 (2018).

Chan, A., Parent, E., Narvacan, K., San, C. & Lou, E. Intraoperative image guidance compared with free-hand methods in adolescent idiopathic scoliosis posterior spinal surgery: a systematic review on screw-related complications and breach rates. Spine J. 17(9), 1215–1229 (2017).

If you are experiencing chronic back or leg pain that is unresponsive to conservative treatments, then you may be a candidate for minimally invasive spine procedure in conjunction with our robotic spinal system.

Robots have been used in surgery for years. Dr. Webb was fortunate to spend time training on Robotic Spine Surgery during his fellowship, learning under the guidance of Dr. Isador Lieberman-one of the surgeon pioneers and innovators of the spinal robot.

Robotic spine surgery is a form of minimally invasive spine surgery that involves the use of a robotic arm to assist surgeons in the placement of screws and other hardware into the spine with accuracy and precision. Robots do NOT replace surgeons in performing your surgery, but simply augment the surgeon so surgery is done in a more precise manner. The term, “robot,” implies a machine capable of carrying out a complex series of actions automatically. A true spinal surgery robot has yet to be created. Rather, they were designed to interact and assist surgeons – created in an attempt to make spine surgery safer and more efficient.

In addition, the spinal robot can assist surgeons in optimizing patient care by using computer navigation, much like a GPS in your car. The potential benefits for patients include a shorter hospital stay, less tissue damage and therefore less blood loss, less radiation exposure, and smaller incisions.

How It Works

When using the spinal robot, Dr Webb is able to plan for your surgery using a computer application days and even weeks before surgery.

Using the computer application, Dr. Webb can use your imaging studies to determine the size and trajectory of your screws and hardware. Then a patient specific plan is made based off of your 3D anatomy. This plan is used to guide the rigid robotic arm to a specific region of your spine during surgery, similar to a planned route or pathway on a GPS. The surgeon uses this pathway or route to accurately place the pedicle screws and other hardware on the day of surgery. By doing this, Dr Webb will ensure the correct size implants and screws will be available the day of your surgery and also takes the guesswork out of performing your implantation. This not only saves time in surgery (meaning a shorter surgery), but also decreases complications of misplaced screws.

On the day of surgery, your CT images along with Dr. Webb’s plan (taking into account your specific anatomy) are imported into the robotic computer system. The arm of the robot is the. mounted onto the surgical bed as well as rigidly attached to your spine via a small pin that Dr.Webb will insert during surgery. The robotic arm can move in 6 degrees of freedom to provide the preplanned screw trajectory and entry point thereby allowing Dr. Webb to manually perform the drilling and screw insertion through either an open or percutaneous procedure. During surgery, the operator of the robot will be present to direct the robotic arm to specific areas of your spine to accurately place the screws and other hardware with precision.

Using computer guided navigation, in addition to the robot, allows Dr Webb to display the surgical instruments and implants on a computer screen for Dr. Webb and the rest of the operating room staff to monitor throughout the case. This display allows Dr. Webb to view live feedback during your procedure for more precise implant placement.

It is important to understand that the decision to receive minimally invasive robotic spine surgery is individualized to each patient and their symptoms. Dr. Webb will discuss whether you are a candidate for this procedure at your visit.

References

Lieberman IH, Kisinde S, Hesselbacher S. Robotic-Assisted Pedicle Screw Placement During Spine Surgery. JBJS Essent Surg Tech. 2020;10(2):e0020. Published 2020 May 21. doi:10.2106/JBJS.ST.19.00020

Vo CD, Jiang B, Azad TD, Crawford NR, Bydon A, Theodore N. Robotic Spine Surgery: Current State in Minimally Invasive Surgery. Global Spine J. 2020;10(2 Suppl):34S-40S. doi:10.1177/2192568219878131

Staub BN, Sadrameli SS. The use of robotics in minimally invasive spine surgery. J Spine Surg. 2019;5(Suppl 1):S31-S40. doi:10.21037/jss.2019.04.16

D’Souza M, Gendreau J, Feng A, Kim LH, Ho AL, Veeravagu A. Robotic-Assisted Spine Surgery: History, Efficacy, Cost, And Future Trends [published correction appears in Robot Surg. 2019 Dec 23;6:25]. Robot Surg. 2019;6:9-23. Published 2019 Nov 7. doi:10.2147/RSRR.S190720

Cervical = area of your neck at the top of your spine

Disc = intervertebral disc that is compressing on your spinal cord/nerves in the neck

Replacement = replacing diseased/degenerated disc material with a metal or plastic cage.

A cervical disc replacement, also called artificial disc replacement (ADR), is a procedure that removes your degenerated disc and replaces this area with a biomechanical device that is designed to maintain/preserve mobility in your neck. This is similar to a hip or knee replacement which are designed to restore natural joint mobility.

Why do a cervical disc replacement vs a fusion?

There are many advantages of doing a disc replacement rather than a fusion of your neck.

1. Maintain your neck motion: a fusion operation fuses the bones in your neck, causing you to lose motion in that area of your spine. Alternatively, a disc replacement helps you to maintain your motion.
2. Lowers the chance that you will need additional spine surgery in the future: when spinal segments are fused, there is a chance that the loss of motion in the fused segment adds stress on the levels above or below the fusion, which may cause those levels to break down faster. A disc replacement allows you to maintain your motion, thus decreasing the chance that the levels above and below this site break down.
3. Quicker recovery : a fusion operation fuses the bones in your neck which can take anywhere from 8-12+ weeks whereas in a disc replacement, there are no bones that need to fuse together meaning you can return to activities and the things you love to do sooner.

Who is a good candidate for a cervical disc replacement?

Generally, patients who are younger, have good bone quality, minimal arthritis, more arm pain than neck pain, and soft disc herniations are good candidates for this procedure. Dr. Webb can discuss whether you are a good candidate for this procedure at your visit.

Approach

The surgery is done by making a small incision on either the right side or left side of your neck. This will be decided by Dr. Webb and discussed with you at your visit. Doing the surgery by going through the front of your neck has many advantages over doing a surgery from the back (posterior) of your neck including:

• Lower infection risk vs going through the back of your neck.
• Generally, a quick surgery and shorter recovery than going through the back of your neck.
• Less blood loss
• Less postoperative pain
• Less muscle damage: muscles are not cut, they are moved to the side and allowed to fall back in place when surgery is done.

The Procedure

Anesthesia & Induction

• Your anesthesiologist will talk to you about the specifics of his/her plan for the procedure. You will find out what medications and what type of anesthesia will be used to keep you pain free and comfortable throughout the operation.
• In general, most patients will undergo general anesthesia during spine procedures meaning you will be asleep and wont remember or feel any pain during the procedure itself. Patients may have pain upon waking up from anesthesia, but this will be managed with intravenous and oral pain medications.
  • After a breathing tube is placed and you are fully asleep, you will be positioned on the operating room table.
  • Surgery will not begin until you are asleep and given pain medications so that you don’t feel any pain during the procedure.
• A skin incision is made on the left or right hand side of the anterior neck (depending on surgeon preference). After dissecting through the skin, Dr. Webb will find the space between your esophagus and trachea (windpipe). He will carefully move these out of the way. In between these two structures lies your spine.
  • No muscles are cut, they are just moved to the side and held apart with the use of special tools, called retractors.

Performing the Decompression

• Before removing the diseased disc, Dr. Webb will confirm that he is operating at the correct level by taking an x-ray while you are asleep.
  • When the level is confirmed, Dr. Webb will then begin the decompression (removing the areas of compression from your spinal cord) portion of the procedure.
  • Dr. Webb will then carefully remove the disc that is pressing on your spinal cord/nerves with the use of special instruments and tools.
  • With the diseased disc removed, any additional surrounding structures which may be pressing on your spinal cord, such as bone spurs and/or excess ligaments, will be removed.
  • Dr. Webb will then ensure that your spinal cord and nerves are free from compression.

Performing the Disc Replacement

• After the spinal cord has been decompressed and all the diseased disc material removed, this area/void needs to be replaced with something.
  • This area will now be replaced a metal artificial device, called an artificial disc.
  • The artificial disc will indirectly decompress your spinal cord and nerves by “jacking open” your disc space.
    • This is similar to “jacking up” and changing your tires on your car after a flat tire. When your car is “jacked up”, there is more room for the tire to be placed and also relieves pressure off of the tire. Similarly, in spine surgery when a metal or plastic cage is placed in between your bones, this “jacks up” the space that houses your spinal cord and nerves, giving them more room.

Closure

• The retractors that held the area between your trachea and esophagus apart will now be removed and the trachea/esophagus will be allowed to fall back into their normal position.
• Dr. Webb uses absorbable sutures to close your wound. These sutures do not typically need to be removed and will absorb on their own.
• Sometimes, a special tube called a drain will be used. This is to collect any blood or fluids that can collect after surgery. This drain will be removed before you leave the hospital, usually the next day after surgery.

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Frequently Asked Questions

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What can I expect after surgery?

After surgery you will be transferred to the recovery room, also called the PACU (post anesthesia care unit). After you have awaken from the anesthesia, you will then be transferred to your hospital room. This is typically when your family members can visit you.

Either the same day or the following morning after surgery, a physical and/or occupational therapist will begin your therapy. During your hospital stay, you will be given medications to help with pain and IV antibiotics to minimize the risk of infection. Most patients spend 1-2 nights in the hospital and are discharged home after:

1. You are tolerating a diet
2. Your pain is controlled
3. After you have worked with and passed physical therapy.

Walking after surgery is highly encouraged, even the same day of surgery!

What kind of recovery can I expect after surgery?

Recovery from a cervical artificial disc replacement surgery takes 8-12 weeks, but patients continue to heal for up to a year after surgery.

When can I return to work and/or activities?

Walking is highly encouraged, immediately after surgery and throughout your post operative period. Most patients can return to a light desk job or household activities by 2-3 weeks after surgery. Patients with jobs that require heavy lifting or strenuous labor will not be allowed to return until Dr. Webb ensures your implant is stable and growing into the bones solidly. In addition, activities such as biking, skiing, or running will not be allowed until Dr. Webb ensures your implants have grown into place.

When will my neck or arm pain go away?

If you can imagine putting your elbow on a hard surface for a long time, what happens? Your fingers start to go to sleep. Why? Because the nerves to these fingers is compressed, is asleep, and is irritable. Once you realize this, you pick up your elbow (to remove the pressure off the nerve) and shake your fingers until they wake up.This is a similar concept in spine surgery where depending on how long your nerves and spinal cord have been compressed, will determine how long it takes for the nerve to wake up after the surgery. If you have had compression of your nerves and spinal cord for months to years, then it may take some time before the nerve recovers and wakes up (if it recovers at all). Most patients, however wake up from surgery with arm pain relief meaning that the debilitating arm pain they had before surgery has went away, but may have some neck pain and spasms from the surgical incision itself. This pain will be controlled with oral/IV pain medications and antispasm medications throughout your hospital stay.

What complications should I be aware of?

Inadequate relief of symptoms

• Dr. Webb is very particular about making sure we target the right level of your spine that may be causing your symptoms.
• Inadequate relief of symptoms after surgery could be due to a number of things including: multiple levels that are degenerated or worn out that will not be addressed in surgery, surgery done on the wrong level, or advanced and severe spinal cord compression that may be irreversible.
• Injections are confirmatory and are very predictive of how well you will do with surgery. These spinal injections, usually done before surgery in the conservative treatment period, are essential in determining which level of your spine is the cause of your symptoms.
• Just because you have multiple degenerated areas of your spine according to your imaging studies (MRI, X-ray, etc.), does not mean every level needs an operation.

Nerve damage, causing speech or swallowing issues

• There are small nerves that control your larynx (voice box) that reside very close to the surgical site.
• Dr. Webb carefully works around these nerves and ensures they are not damaged during surgery.
• If they become irritated by surgery, your voice may be hoarse for weeks to months after surgery until the nerve recovers.
• Some patients may also have a sore throat from the endotracheal (breathing tube) placed during surgery or from the retraction of the esophagus and windpipe during surgery. This tends to get better after surgery.

Dural tear

• The dura is the outer layer of the spinal cord. Sometimes, this layer can be especially thin in certain patients and very friable. During surgery, if there is a small tear in this layer, Dr. Webb will attempt to repair it. This is a not a very common complication, but definitely one that needs to be known.
• Sometimes after a dural tear is repaired, Dr. Webb may ask that you sit upright for 24 hours after surgery. This is done to give the repair time to heal and to ensure his repair does not come apart.
• Fortunately, multiple studies have shown that having a dural tear repair does not affect your outcome from surgery.

Infection

• Very low risk (<1%) but this risk is increased if you are overweight, immunosuppressed, on chronic steroids, or diabetic.
• Antibiotics will be given before surgery starts and also given for 24 hours after surgery while you are in the hospital to decrease the risk of infection.

Bleeding

• Very low risk, but increased if you are taking blood thinners, fish oil, herbal medications or have a clotting disorder.
• These medications will need to be stopped before surgery.
• Sometimes, a special tube called a drain will be placed during surgery. This tube is to collect any blood or fluids that can collect after surgery. This drain will be removed before you leave the hospital, usually the next day after surgery.

Spinal cord or Nerve damage

• Very low risk
• A neuromonitoring technician is a professional trained in the monitoring of your nerves and spinal cord.
• This person (along with a Neurologist) is part of the team that will be taking care of you during surgery and will help Dr. Webb monitor your nerves and spinal cord throughout the procedure.
• You will be able to meet this person the morning of surgery and ask any questions about their role in your care.
• Generally, after you are asleep from anesthesia, this technician will place small wires on your legs and arms so that the nerves and spinal cord and be monitored during surgery.

Patient Specific Spinal 3D Printing

If you are experiencing chronic back or leg pain that is unresponsive to conservative treatments, then you may be a candidate for minimally invasive spine surgery in conjunction with a 3D printed spinal implant.

Spinal fusion is a procedure that aims to join two or more vertebrae in the spine with the use of a spinal implant, made either out of titanium or plastic. Along with bone graft, these items will help fuse your spine to minimize motion and provide stability.

Spinal 3D-printing of customized spinal implants is a cutting-edge technique that offers improved outcomes for spinal fusion patients.

Spinal 3D-printing refers to a process where a 3D object is created from a digital design through successive layering of material under computer control, so called ‘additive manufacturing’.

Having gained much interest in recent years, 3D printing has found applications in many surgical and medical fields. Custom 3D printing of implants for spinal surgery has a potential to improve patient outcomes and results from surgery. 3D-printed implants have a special design and can be custom printed to match your individual needs. Each implant is 3D-printed in multiple shapes and sizes which are matched to the patient during surgery. This allows the implant to be custom-fit to your individual anatomy. The surgical instruments used to perform the procedure can also be printed to match your body’s needs.

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Frequently asked Questions

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Who is eligible to receive a 3D-printed spinal implant?

Most patients, except those with allergy or reactions to the metal, are eligible to receive 3D-printed implants. The technology can be particularly helpful in severe or complex cases that require multiple levels of fusion or higher fusion rates. Dr Webb can discuss at your visit whether a 3D-printed implant may be an option for your spinal fusion procedure.

Why should you consider 3D-printed spinal implants?

A major goal of a spinal implant design is to both help reestablish the spine’s proper anatomy and to help it fuse in that position. 3D printing can help achieve both of these goals. By creating a wide variety of heights, angles, and depths, the number of different shapes and sizes for implants is endless. This allows surgeons to use more patient-specific implants to achieve clinical success through ideal anatomic restoration. In most circumstances, the huge number of implant options that are on the market is all that is needed for a patient. However, there are situations where having a true patient-specific implant is needed such as when a patient has aberrant or not commonly sized anatomy.

What are the benefits of 3D spinal implants? 

Complex spinal deformity, tumors, trauma, or infection frequently result in significant bony distortion and thus a normal implant off the shelf is not usually sufficient to fill this void. 3D printing technology allows a truly ideal and patient specific implant to be created to the individual’s circumstance.

In addition, the spinal Implants can be 3D printed in ways that allow for bony fusion. Certain metals, such as titanium, are ideal to achieve bony union. In general, an implant needs to roughly mimic the properties of bone in order to heal and fuse fully. If the implant is too stiff and rigid, it can indent and settle into bone, thereby losing the spacing and postural correction that was needed to achieve clinical success. If it is too soft, it simply doesn’t support the weight and can break. 3D printing can be utilized to create the ideal property match to minimize both of these potential catastrophic failures.

Lastly, 3D printing allows for the creation of the ideal surface on the implant which will allow fusion. The smaller the pores of an implant on the surface, the more surface area that bone can form onto. 3D printing allows for these microscopic roughened surfaces to be created, therefore increasing fusion rates.

References

Wallace N, Schaffer NE, Aleem IS, Patel R. 3D-printed Patient-specific Spine Implants: A Systematic Review. Clin Spine Surg. 2020 Jun 16. doi: 10.1097/BSD.0000000000001026. Epub ahead of print. PMID: 32554986.

Burnard JL, Parr WCH, Choy WJ, Walsh WR, Mobbs RJ. 3D-printed spine surgery implants: a systematic review of the efficacy and clinical safety profile of patient-specific and off-the-shelf devices. Eur Spine J. 2020 Jun;29(6):1248-1260. doi: 10.1007/s00586-019-06236-2. Epub 2019 Dec 3. Erratum in: Eur Spine J. 2020 May 26;: PMID: 31797140.

Wilcox B, Mobbs RJ, Wu AM, Phan K. Systematic review of 3D printing in spinal surgery: the current state of play. J Spine Surg. 2017 Sep;3(3):433-443. doi: 10.21037/jss.2017.09.01. PMID: 29057355; PMCID: PMC5637198.

Hsu MR, Haleem MS, Hsu W. 3D Printing Applications in Minimally Invasive Spine Surgery. Minim Invasive Surg. 2018 Apr 1;2018:4760769. doi: 10.1155/2018/4760769. PMID: 29805806; PMCID: PMC5899854.