mri of degenerative disc disease
Fig. 4
MRI of degenerated disc
(larger view)

Fig. 5
Placement of artificial disc
at L5-S1
(larger view)

The following profiles one patient's experience with the CHARITÉ Artificial Disc. This patient was a participant in the US multi-center clinical trial to study the effectiveness and safety of the device.

History of Back Pain

The patient is a 33-year-old Caucasian female who had 2 prior lumbar laminectomy surgeries at L5-S1 (the bottom level of the spine). Her leg pain improved after these two spinal operations, but her low back pain increased due to progressive collapse of the L5-S1 intervertebral disc.

She tried three years of conservative therapy, including physical therapy, ultrasound, acupuncture, and epidural steroid injections, all of which failed to relieve her ongoing low back pain. A subsequent pregnancy increased the stress on her lumbar spine and made the low back pain significantly worse.

Prior to her disc replacement surgery, the patient's pain was preventing her from performing routine tasks, such as getting dressed, getting in and out of the car, and lifting groceries, and she had missed a lot of work. The patient admitted that she was taking too much pain medication in order to perform routine daily activities. She could not perform any athletic activities such as riding a bike, aerobic walking, or swimming. She was otherwise healthy and did not smoke.

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Physical Exam

On physical exam, the patient primarily had mechanical lower back pain (90% of pain in the back; 10% of pain in back of the thigh).

The patient's neurological exam was normal but her spinal mobility was severely restricted. While in the standing position and with her knees locked in the straight position she could not even bend forwards to touch her kneecaps (much less her toes). Spinal extension (bending backwards) increased her low back pain. She had very little endurance while working and had increased pain while sitting or driving.

Diagnostic Tests

An X-ray showed that the L5-S1 disc space was completely narrowed, and an MRI scan confirmed that the L5-S1 disc was severely degenerated. There were also Modic changes, which means that there was bone marrow edema and inflammatory changes of the vertebral body bone adjacent to the collapsed disc.

A discogram showed concordant pain with injection of a very small amount of saline into the center of the disk at L5-S1. This injection reproduced the distribution and intensity of the patient's major pain. After characterizing the patient's pain response, a small amount of long acting anesthetic was injected and this relieved her characteristic, activity limiting pain. The discogram did not reproduce the patient's pain with injections at either the L3-L4 or at L4-L5 levels (normal discs) (see Figure 4).

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CHARITÉ Artificial Disc Surgery

The patient decided to enroll in the clinical trial for disc replacement surgery. The CHARITÉ prosthesis was used in a disc replacement surgery that took approximately 90 minutes to perform. The first day following the surgery, the patient was allowed out of bed to sit in a chair. Aside from discomfort from the incision in her lower abdomen, the patient reported that she felt relatively comfortable after surgery.

Following CHARITÉ Artificial Disc Replacement Surgery

The patient was discharged from the hospital three days after surgery and started rehabilitation (physical therapy) two days after surgery. She continued rehabilitation for seven weeks following the surgery to build up her abdominal and paraspinal muscle tone.

Initial follow-up

At her 6 week postoperative check up, the patient was bending normally and able to pick up her baby. She had returned to office work and was able to drive back and forth to work, a less than one hour commute. From an objective standpoint, the Oswestry scale measurement of her pain improved from 55 (nearly disabled) to 5 (the normal amount of back pain ranges from 0 to 10).

Her postoperative radiographs showed good bending motion at the L5-S1 level. The important thing is that the disc space collapse had been corrected, which increases the height of the neuroforamen, meaning that there is the normal amount of room for the nerve roots. The Modic changes or inflammatory reaction adjacent to the disc had resolved. The position of the components of the disc prosthesis was excellent (see Figure 5).

Longer term follow-up

Five years after CHARITÉ reconstruction of the patient's collapsed disk, her back pain disability has resolved and she is doing fine. She reports that she has taken her kids and walked throughout Disneyworld, danced all night at weddings, and returned to work full time running a busy dental practice. The range of motion and flexibility of the patient's back has continually improved since the date of surgery.