USC Center for Spinal Surgery
Minimally Invasive Spinal Fusion
Overview and Indications
Using innovative technology, a minimally invasive surgery (MIS) spinal fusion (mending the spine bones together) can now be accomplished using two small poke-hole incisions with minimal tissue dissection resulting in a faster recovery. Using the MIS procedure, Posterior lumbar fusions (PLF) and transforaminal lumbar interbody fusions (TLIF) can both be performed in less time, with less tissue damage, and less pain than traditional open spinal fusion surgery.
Posterior Lumbar Fusion (PLF) is the general term used to describe the technique of surgically mending two (or more) lumbar spine bones together along the sides of the bone. Bone graft is placed along side the spine bones (not in between the disc spaces, which is called an interbody fusion), and ultimately fuses together. Minimally invasive PLF is generally always performed in conjunction with instrumentation (use of metal screws/rods) so as to impart immediate stability while the bone mends and to increase the fusion rate (percentage of patients where the bone successfully mends together). MIS TLIF includes the PLF described above, as well as performing an interbody fusion, which means the intervertebral disc is removed and replaced with a bone spacer (metal or plastic may also be used). A MIS TLIF involves placing only one bone graft spacer in the middle of the interbody space, without retraction of the spinal nerves.
The MIS PLF technique is often favored as the 2nd staged procedure when a multiple level ALIF is performed, and a laminectomy is not necessary. A MIS TLIF is commonly performed when one or two spinal levels are being fused in conjunction with a partial posterior decompression (facetectomy and laminectomy), and interbody fusion is indicated.
MIS PLF and MIS TLIF are commonly performed for a variety of spinal conditions, such as spondylolisthesis and degenerative disc disease, among others.
The surgery is performed utilizing general anesthesia. A breathing tube (endotracheal tube) is placed and the patient breathes using a ventilator during the surgery. Preoperative intravenous antibiotics are given. Patients are positioned in the prone (lying on the stomach) position, generally using a special operating table/bed with special padding and supports. The surgical region (low back area) is cleansed with a special cleaning solution. Sterile drapes are placed, and the surgical team wears sterile surgical attire such as gowns and gloves to maintain a bacteria-free environment.
A 1 inch (depending on the number of levels) poke-hole incision is made on each side of the low back, directly over the involved spinal levels. The fascia and muscle is gently divided using special cannulated retractors and sleeves. The pedicle screws and rods are implanted and the facet joints are fused through the two tiny incisions under x-ray guidance. If a TLIF is to be performed, a partial laminectomy (removal of lamina portion of bone) and complete facetectomy is performed to allow visualization and removal of the intervertebral disc. The intervertebral disc is then removed using special biting and grasping instruments (such as a pituitary rongeur, kerrison rongeur, and curettes), an operating microscope, and x-ray guidance. Special distractor instruments are used to restore the normal height of the disc, as well as to determine the appropriate size spacer to be placed. A bone spacer (metal or plastic spacers may also be used) is then carefully placed in the disc space.
The wound areas are usually washed out with sterile water containing antibiotics. The deep fascial layer and subcutaneous layers are closed with one or two sutures. The skin can usually be closed using special surgical glue, leaving a minimal scar and requiring no bandage.
The total surgery time is approximately 2 to 3 hours, depending on the number of spinal levels involved.
Most patients are usually able to go home 1-3 days after surgery. Patients will typically stay longer, approximately 2-5 days, if an anterior spinal surgery is also performed. Before patients go home, physical therapists and occupational therapists work with patients and instruct them on proper techniques of getting in and out of bed and walking independently. Patients are instructed to avoid bending at the waist, lifting (more than five pounds), and twisting in the early postoperative period (first 2-4 weeks) to avoid a strain injury. Patients can gradually begin to bend, twist, and lift after 4-6 weeks as the pain subsides and the back muscles get stronger.
Patients are generally not required to wear a back brace after surgery. Occasionally, some patients may be issued a soft or rigid lumbar corset that can provide additional lumbar support in the postoperative period, if necessary.
The wound area can be left open to air. No bandages are required. The area should be kept clean and dry.
Patients can shower immediately after surgery, but should keep the incision area covered with a bandage and tape, and try to avoid the water from water hitting directly over the surgical area. After the shower, patients should remove the bandage, and dry off the surgical area. Patients should not take a bath until the wound has completely healed, which is usually around 2 weeks after surgery.
Patients may begin driving when the pain has decreased to a mild level, which usually is between 7-14 days after surgery. Patients should not drive while taking pain medicines (narcotics). When driving for the first time after surgery, patients should make it a short drive only and have someone come with them, in case the pain flares up and they need help driving back home. After patients feel comfortable with a short drive, they can begin driving longer distances alone.
Return to Work and Sports
Patients may return to light work duties as early as 1-2 weeks after surgery, depending on when the surgical pain has subsided. Patients may return to moderate level work and light recreational sports as early as 1-2 months after surgery, if the surgical pain has subsided and the back strength has returned appropriately with physical therapy. Patients who have undergone a fusion at only one level may return to heavy lifting and sports activities when the surgical pain has subsided and the back strength has returned appropriately with physical therapy. Patients who have undergone a fusion at two or more levels are generally recommended to avoid heavy lifting, laborious work, and impact sports.
Doctor's Visits and Follow-Up
Patients will return for a follow-up visit to see the doctor approximately 12-14 days after surgery. The incision will be inspected. There is one suture that will be removed. Medications will be refilled if necessary. Patients will usually return to see Dr. Spoonamore or Dr. Smith every 4-6 weeks thereafter, and an x-ray will be taken to confirm the fusion area is stable and healing appropriately. At 6-10 weeks after surgery, patients will be given a prescription to begin physical therapy for gentle back exercises.
Results and Outcome Studies
The results of Minimally Invasive Spinal Fusion (MIS PLF or MIS TLIF) surgery in the treatment of symptomatic spondylolisthesis and degenerative disc disease are generally excellent. Numerous research studies in medical journals demonstrate greater than 92-98% good or excellent results from MIS fusion surgery. Most patients are noted to have a significant, rapid improvement of their back pain and return to many, if not all, of their normal daily and recreational activities.
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