Microdiscectomy is a minimally invasive spine surgery aimed to relieve pain or pressure on the spinal cord associated with a damaged herniated lumbar disc.
Dr. Benjamin Bjerke, a fellowship-trained neurosurgeon and orthopedic spine surgeon with Iowa-based Capital Orthopaedics & Sports Specialists
who specializes in surgical procedures of the cervical spine as well as minimally invasive lumbar procedures, discusses microdiscectomy in this expert interview.
What is microdiscectomy?
So, a microdiscectomy is taking out a herniated disc
generally that is pressing on nerves in the spine. A lot of people have questions about what part of the disc we're going to take out, or whether that disc is doing them any good. When we do a microdiscectomy, it's only the piece that's herniated, generally into the spinal canal or into the foramen where the nerve roots are being compressed. It's just the pathologic piece that's removed.
A lot of surgeons used to remove a lot of the disc. They used to go in and take out the normal disc, but just like the meniscus in the knee, we've noticed that your native disc provides some cushion, and we want to leave as much as possible. So, the goal of a microdiscectomy is just to take out that pathologic piece. A lot of people are worried that they're going to need that piece later, that we may want to put something back where that was supposed to be. But again, we only take out the pathologic piece that's not doing you any good, and that gets thrown in the garbage.
Is there something you fill the space with, or is it pretty much stable after the removal of the bad disc area?
Dr. Bjerke: You don't put anything back because the microdiscectomy, the piece of disc that you take out is in a bad place. It's pushing on nerves. So there's no replacement. There's no putting anything back. Once that disc has gone out of the natural position where it's supposed to be, it's gone forever.
What are the signs and conditions that someone might need a microdiscectomy?
Dr. Bjerke: The absolute signs of anybody that would absolutely need a microdiscectomy are problems with weakness. So, weakness in one side or the other, either about the ankle, feet, or, in extreme cases, problems with bowel or bladder dysfunction. For other people, we generally wait and we will try conservative measures for a while if you don't have any motor weakness. If those patients have enough pain for enough time and have tried enough things and it still bothers them, those patients would be a candidate for a microdiscectomy as well.
Prior to a microdiscectomy, are patients required to try conservative treatments to see if there's any relief?
Dr. Bjerke: It depends on the symptoms. So if someone comes in and they have any problems with their bowel and bladder, for example, those patients absolutely go to surgery. There's no other option unless they're not healthy enough for surgery. For patients with weakness on one leg or the other, those patients, we have a much lower threshold to bring back to surgery. For patients with just pain, no matter how severe, we generally do some medication management, physical therapy, chiropractic care, injections, et cetera, before moving on to surgery.
Are there any factors that affect or prohibit surgery at all for people who need a microdiscectomy?
Dr. Bjerke: People on blood thinners and people who have had surgery before make that procedure more difficult, and I'll get into that later. That's about it. Or patients that just aren't healthy enough for surgery.
Not healthy enough … Would that be obesity? Would it be some other factors?
Dr. Bjerke: A number of things. We just say comorbidities, but obesity and body mass are certainly one of those. Not only does it make it harder for the patient to recover, but it makes the microdiscectomy procedure itself more difficult. So I would say it's a relative contraindication. Over a certain [weight], some surgery centers or some anesthesiologists will not undergo surgery if it's considered elective. So for example, BMI over 50. Those patients can't have a microdiscectomy unless it's extreme.
"We only take out the pathologic piece
that's not doing you any good."
So, what happens during the procedure?
Dr. Bjerke: So microdiscectomy is performed in a number of ways. It can be done through a small tube, through a minimally invasive approach, which is the way that I do. So the skin is incised about an inch or less, and then serial dilators are placed into the paraspinal muscles, the muscles alongside the spine, to accommodate a tube that's about just under an inch in diameter. It's docked on the lamina, or the bone covering the nerve roots. That bone is then drilled away. Some ligaments are also removed. The nerve roots are moved to the side, and the pathologic disc is then removed. Some people are worried that that bone needs to be replaced or somehow it's potentially dangerous to remove that bone. It's a very small keyhole of bone that needs to be removed, so that's not a big issue.
What's the access point? Is the access point through the abdomen, or is it directly through the back?
Dr. Bjerke: It is through the back.
About how long is the procedure?
Dr. Bjerke: I would say between 30 and 60 minutes.
And is it an outpatient procedure, or is it inpatient?
Dr. Bjerke: For most surgeons, the overwhelming majority is outpatient. All my microdiscectomies are outpatient.
What's your typical surgery prep for a patient? What do you tell them to do to prepare for surgery?
Dr. Bjerke: I try to wean patients from narcotics if they're taking them before surgery. Because surgery is going to cause them pain, I need them to be as naive as possible to strong medication so we can treat the surgical pain with those. Other than that, that's about it. Just keep doing what you're doing. Keep your flexibility, keep your strength up. Bed rest is definitely not the answer.
What's the recovery protocol for patients who've undergone a microdiscectomy?
Dr. Bjerke: It depends on the surgeon. I would say some surgeons are a little more conservative, and that would include myself. I ask patients not to bend, lift over 10 pounds, or twist for a total of six weeks. The reason is generally during a microdiscectomy, we have to incise the annulus or the posterior portion of the disc. That needs about six weeks to scar over so that a new herniated disc doesn't happen.
And then is there any associated physical therapy that goes on during or after?
Dr. Bjerke: So, if a patient has weakness in one or either leg before surgery and still has it after, I'll generally start them on early physical therapy to include just leg strengthening, but I completely avoid any lumbar range of motion or flexibility or core strengthening for six weeks. I place my patients in a lumbar spine brace for six weeks, just to remind them of those facts. After six weeks, their lumbar flexibility and core strength are going to be pretty bad. And so at six weeks, we'll start them on at least a few visits to physical therapy for that.
Updated: June 5, 2021