Artificial Disc Replacement (ADR)

Overview and Indications

Artificial disc replacement (ADR) is newer type of spinal disc procedure that utilizes an anterior (front - through the abdominal region) approach to replace a painful, arthritic, worn-out intervertebral disc of the lumbar spine with a metal and plastic prosthesis (artificial disc). Currently, the artificial disc replacement is only FDA-approved in the United States for use in the lumbar (low back) region, although many products are currently being studied for use in the cervical (neck) region.

Artificial disc replacement is primarily considered for patients with isolated 1-level (one disc only) degenerative disc disease. Prior to the development of ADR, spinal fusion was the principal treatment for painful degenerative disc disease that failed to improve with nonoperative management. ADR is generally NOT recommended for patients with spinal fractures, instability, neurologic compression, or multiple level degenerative disc disease - spinal fusion remains the treatment of choice for these conditions. The advantages of ADR include a faster recovery time than spinal fusion and preserved motion at the disc level. The theoretical long-term advantage of ADR, which remains unproven, is the possibility of decreased adjacent level stress and arthritis compared with spinal fusion.

Surgical Technique

The surgery is performed utilizing general anesthesia. A breathing tube (endotracheal tube) is placed and the patient breathes with the assistance of a ventilator during the surgery. Preoperative intravenous antibiotics are given. Patients are positioned in the supine (lying on the back) position, generally using a special, radiolucent operating table. The surgical region (abdominal 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 3-8 centimeter (depending on the number of spinal discs to be replaced) transverse or oblique incision is made just to the left of the umbilicus (belly button). The abdominal muscles are gently spread apart, but are not cut. The peritoneal sac (containing the intestines) is retracted (moved to the side) to the side, as are the large blood vessels. Special retractors are used to allow the surgeon to visualize the anterior (front part) aspect of the intervertebral discs. After the retractor is in place, an x-ray is used to confirm that the appropriate spinal level(s) is identified.

The intervertebral disc is then removed using special biting and grasping instruments (such as a pituitary rongeur, kerrison rongeur, and curettes). Special distractor instruments are used to restore the normal height of the disc, as well as to determine the appropriate size artificial disc replacement to be implanted. The artificial disc prosthesis is then carefully placed in the disc space. Fluoroscopic x-rays are taken to confirm that the prosthesis is in the correct position.

The wound area is usually washed out with sterile water containing antibiotics. The deep fascial layer and subcutaneous layers are closed with a few strong 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 discs to be replaced.

Post-Operative Care

Most patients are usually able to go home 2-4 days after surgery. 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.

Brace

Patients are generally not required to wear a back brace after surgery. Occasionally, some patients may be issued a soft lumbar corset that can provide additional lumbar support in the postoperative period, if necessary.

Wound Care

The wound area can be left open to air. No bandages are required. The area should be kept clean and dry.

Shower/Bath

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.

Driving

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 2-3 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 3 months after surgery, when the surgical pain has subsided and the back strength has returned appropriately with physical therapy. Patients who have undergone disc replacement may return to moderate lifting and sports activities when the surgical pain has subsided and the back strength has returned appropriately with physical therapy. Patients who have undergone artificial disc replacement 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 are no sutures to be removed from the anterior wound. Medications will be refilled if necessary. Patients will usually return to see Dr. Spoonamore every 4-6 weeks thereafter, and an x-ray will be taken to confirm the area is stable and healing appropriately. At 8-12 weeks after surgery, patients will be given a prescription to begin physical therapy for gentle back exercises.

Results and Outcome Studies

The results of artificial disc replacement (ADR) surgery in the treatment of symptomatic degenerative disc disease are generally excellent. Numerous research studies in medical journals demonstrate greater than 89-97% good or excellent results from ADR surgery. Most patients are noted to have a significant improvement of their back pain and return to many, if not all, of their normal daily and recreational activities.

Selected Bibliography

Bertagnoli R, Yue JJ, et al. The treatment of disabling multilevel lumbar discogenic low back pain with total disc arthroplasty utilizing the ProDisc prosthesis: a prospective study with 2-year minimum follow-up. Spine 2005;30(19):2192-99.

Cinotti G, David T, Postacchini F. Results of disc prosthesis after a minimum follow-up period of 2 years. Spine 1996;21(8):995-1000.

Delamarter RB, Fribourg DM, Kanim LE, et al. ProDisc artificial total lumbar disc replacement: introduction and early results from the United States clinical trial. Spine 2003;28:S167-S175.

Griffith SL, Shelokov AP, Buttner-Janz K, et al. A multicenter retrospective study of the clinical results of the LINK SB Charite intervertebral prosthesis: the initial European experience. Spine 1994;19:1842-9.

McAfee PC, et al. A prospective, randomized, multicenter Food and Drug Administration Investigational Device Exemption study of lumbar total disc replacement with the CHARITE artificial disc versus lumbar fusion: Part II: evaluation of radiographic outcomes and correlation of surgical technique accuracy with clinical outcomes. Spine 2005;30(14):1576-1583.

McAfee PC, et al. Experimental design of total disk replacement-experience with a prospective randomized study of the SB Charite. Spine 2003; 28(20S):S153-62.

McAfee PC, et al. SB Charite disc replacement: report of 60 prospective randomized cases in a U.S. center. Spine 2003;28(0):424-33.

Tropiano P, Marnay T. Lumbar disc replacement: preliminary results with ProDisc II after a minimum follow-up period of 1 year. Spine 2003;28:362-8.

Zigler J. Clinical results with ProDisc: European experience and U.S. investigation device exemption study. Spine 2003;28(suppl):163-6.