Microdiscectomy

Abstract

Lumbar microdiscectomy performed through a tubular retractor is typically the first minimally invasive operation of spine surgeons. The skin incision is placed further lateral for central the disc herniations and close to midline for foraminal herniations. With experience, the yellow ligament can be penetrated sharply. We prefer to limit the disc removal to the herniation, whenever possible, and not violate the central part of the disc. The retractor tube can be angled cranially or caudally as needed, until the entire disc herniation is removed. Confirmation by fluoroscopy after disc herniation removal is recommended.

Electronic Supplementary Material Microdiscectomy electronic supplementary material

This full-length video illustrates the typical case of a patient with a large central disc herniation, slightly eccentric to the right. The skin incision is placed relatively far from the midline in order to provide better access to the central part of the canal. The yellow ligament is opened with the 11-blade. The disc herniation is removed in several large fragments. The final inspection is documented by fluoroscopy (MP4 750131 kb)

This full-length video illustrates the difficult case of a patient with a large calcified disc herniation. The disc could not be penetrated with the 11-blade, despite multiple attempts, and had to be removed with the high-speed drill, while gently retracting the spinal sac medially. This maneuver required more extensive exposure both laterally, drilling of the medial facet, and medially, drilling off the underside of the spinous process and exposing both sides of the spinal sac (MP4 396036 kb)

This short video illustrates the inspection of the epidural space with a Helen instrument. We prefer to start cranial to the disc and move the Helen over the disc space and under the dural sac until reaching the caudal vertebral body, without any obstacles. The inspection is also carried out medially until reaching the midline. We confirm the completeness of decompression by placing a Penfield 4 above and below the disc space and taking a lateral fluoroscopic image, and then placing the down-biting curette on top of the decompressed posterior longitudinal ligament and take a lateral and then an AP fluoroscopic image (MP4 9866 kb)

This short video illustrates another case of a patient with a large soft disc herniation. A small lateral annulotomy allowed for expression of the disc fragments upon pressure on the posterior longitudinal ligament with the suction tip (MP4 157665 kb)

This short video illustrates the case of a patient with an accidental durotomy upon removal of the nerve root retractor. The durotomy is covered with a dural substitute followed by dural sealant (MP4 206873 kb)

This video illustrates the closure of minimally invasive incisions in anatomical layers (MP4 938267 kb)

Addendum: Informative Letter to the Patient

The following informative letter is NOT intended to cover ALL the possible complications and scenarios. It is only intended to serve as a general guide, to improve patients’ understanding of the operation.

The operation is called a microdiscectomy or laminotomy. We make a small incision (usually less than 1 in.) in the lower back, slightly off the midline to the side of the pain. The muscle tissue is gently pushed aside so we can get down to the bones of the spine. The muscles are sore, stiff, and swollen for several weeks after surgery. We then remove some of the back part of the spinal bones (laminotomy) in order to open the spinal canal. At this point an operating microscope is used to allow us to keep the incision as small as possible, yet have excellent vision so we can see what needs to be done.

The nerves are identified, and we do whatever it takes to “unpinch” them. Sometimes this means removing more bone, and sometimes it requires removal of part of the disc. We sometimes have to enter the more central part of the disc to remove loose material, which is done in order to reduce the chance of another herniation in the future (but it can still occur, and if it happens then possibly another operation will be required).

I have performed this operation many times and consider it routine. Unfortunately it is not “safe,” since every procedure I do as a neurosurgeon has real risk and danger associated with it. Death from anesthesia reaction or massive blood loss is possible. Nerve damage could occur which in its worst form could mean loss of all function below the waist including movement, feeling, and bowel, bladder and sexual function. Infection could occur, and if that happens in a deep space like a disc it could take months of antibiotic treatment to cure. Fortunately, all that is very rare. There are, however, three risks, which are relatively common.

There is a 5–10% chance of dural tear and spinal fluid leakage (which is increased if there has been previous surgery with formation of scar tissue). The dura mater is a leaf that covers and protects the nerves, and is filled with fluid called CSF (cerebro-spinal fluid). If the dura is torn during surgery, the fluid comes out and may get all the way to the skin. If this happens, a second operation for closure of this leakage and placement of a lumbar drain (to divert the fluid from coming out of the dural defect) is usually necessary. There is a 5–10% chance of recurrence of disc herniation, which may require a re-operation similar to the initial one, but with slightly increased risk due to scar formation. Finally, there is a 5–10% chance of painful motion between the bones developing in the future, which might lead to a fusion operation (with screws and rods).

Usually the length of hospitalization is quite brief, in fact either same day or just overnight. Unless there was a dural tear during surgery, you will be asked to get out of bed either the same day or the morning after surgery. A walking program can start within a week or two. This should be done on a level surface (not out in a field stepping in holes). Gradually the length of the walks should be increased until you are up to about 2–3 miles a day, if possible. At about 2–4 weeks there is a follow-up office visit, and at that time you can start a home back exercise program. This starts as gentle stretching and strengthening exercises, and it is normal not to be able to do all of these initially. By trial and error you will be able to develop your own custom-made exercise program by selecting those exercises that don’t irritate or aggravate your condition. As the months pass, it is hoped that you will be able to do some of the exercises that you couldn’t do at first. It is important, however, to try to do something each day. At about 2–6 weeks, most people can return to a light office type job, and by 12 weeks more moderate levels of activity can be resumed. Generally by about 6 months after surgery, about 80% of the improvement is reached, but full recovery (the last 20%) stretches out over a year. Generally physical therapy is not required, but patients who were injured on the job often require special consideration.

Once somebody has a bad back, they always will to some degree. Even the best operation is not a “spine transplant.” Although I help many patients, I can never make anybody completely normal. Heavy manual labor and heavy lifting should be avoided. Permanent restrictions vary among individuals, but as a general guide I advise no lifting more than 40 pounds (a heavy sack of dog food) on an occasional basis, no more than 20 pounds on a frequent basis, and no excessive bending, stooping, or squatting. In addition, many patients with bad backs find it necessary to change positions frequently (i.e., after standing for a while it is necessary to sit, and viceversa).

This operation has been recommended in the belief that your condition is serious and therefore taking the risks of surgery makes sense. I believe this is a good operation that is the best choice for your particular problem. If your only affliction is pain, the decision is yours and yours alone as to whether you can live with it. While I obviously hope and believe that this operation will help you, I cannot give any guarantees or promises about results. It is possible that you could be the same or even worse. Furthermore, my general recommendation is to “live with it” if possible and avoid the risks and uncertainties of surgery. Nevertheless I am offering my surgical services in an attempt to help you, but the decision to proceed is up to you.