RESEARCH - US FDA approves first-ever artificial disk for spine arthroplasty

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US FDA approves first-ever artificial disk for spine arthroplasty

Rheumawire

Nov 3, 2004

Mann

Plano, TX - The US FDA has approved the first ever-artificial disk for

spine arthroplasty, the SB Charite III (DePuy Spine/ & ,

Raynham, MA). Offering an alternative to spine fusion, this new approval

heralds the start of a revolution in treatment offered to patients with

chronic back pain, an expert tells rheumawire.

Consisting of a polyethylene core that slides between 2 metal end

plates, this new artificial disk " is truly a revolution in regard to how

people will be treated, " says Dr Hochschuler (Texas Back

Institute, Plano), who conducted some of the studies that led to the FDA

approval. " This will give us an alternative to spinal fusion, but it's

not for every case, [and] in the past many new technologies have been

overutilized. "

The hope is that artificial disks like the Charite may avoid postfusion

problems, he says. " We hypothesize that if we don't fuse, there will be

fewer changes on the disks above and below the fusion site as well less

destruction and less future surgery above and below this site. "

This disk should be used only in patients with significantly more back

pain then leg pain, he says. " They must have tried at least 6 months of

other treatment, including physical therapy, diet, injection(s), or

bracing, and really all sorts of things to get someone over the pain and

avoid surgery, " he says. " I personally have a back problem, and no one

is operating on me unless it's the last choice. "

The clinical trials that led to the approval were conducted with

patients aged 20 to 60, he says, and this remains the basic age range of

potential candidates. Patients with significant osteoporosis, who are

pregnant, or who have any infections are also not good candidates for

arthroplasty with Charite.

" There is a learning curve [to using the Charite], " he says.

Specifically, DePuy Spine/ & will require all surgeons to

go through " rigorous didactic and hands-on training, " he tells

rheumawire. As a matter of fact, the first group of students will be the

board of directors of the North American Spine Society, he says.

" It's really kind of hot, " he says. " Many surgeons are working on other

disks that are not approved, so it behooves us to teach them how to use

the Charite so they can deal with demand, " he says.

" The training is a day and a half for surgeons who have done anterior

spinal surgery before, " he says. " The biggest problem when going through

the front to get the spine is that this approach can be fraught with

danger [because you must maneuver around many vital organs], " he says.

" At Texas Back, we have done thousands of anterior approaches, and

vascular surgeons get us there in 5 to 7 minutes safely, " he says.

It's not just spine surgeons but also the vascular surgeons who need to

be educated, he says. Typically, 2 surgeons are needed for the

artificial-disk operation. A general surgeon approaches the spine

through an abdominal incision, and a spine surgeon then removes the

damaged disk and creates space for implantationfirst the 2 end plates

and then the core in the middle, through the use of specialized

instruments. The 2 end plates (made of a cobalt chromium alloy) are

pressed into the vertebrae above and below the disk space, and teeth

along the border of the end plate grip the bone. A polyethylene core is

then placed between the end plates. The procedure can take 60 to 90

minutes.

" If a person has a huge ruptured disk in their back and we have to go in

through their back, we don't want to go in through their front and

remove another disk because it's not necessary, " Hochschuler says.

Rheumawire reported earlier on the data leading up to FDA approval. In a

2-year study, patients implanted with the Charite disk improved more

quickly than those who underwent fusion surgery. Moreover, patients who

received the artificial disk scored higher on pain and function scores

compared with fusion patients [1]. Patients in the Charite group were

also discharged from the hospital a half day earlier than spinal-fusion

patients, and the 2 groups were comparable in terms of complication

rates. The results were presented in March 2004 at the 20th annual

meeting of the American Association of Neurological Surgeons/Congress of

Neurological Surgeons (AANS/CNS) Section on Disorders of the Spine and

Peripheral Nerves in San Diego, CA.

In this study, average range of motion in the disk group was 7.4 at 2

years, according to radiographic findings. Disk-space height was

restored from an average of 5.7 mm before surgery to 12.9 mm at 2 years

after surgery. After the procedure, 88% of patients were satisfied with

the Charite disk procedure, compared with 81% of spinal-fusion patients.

In light of the FDA approval of the Charite, the Texas Back Institute

opened the nation's first center dedicated to the study and application

of spine arthroplasty.

So far, the waiting list is 80 patients long, says Dr Blumenthal

(Texas Back Institute), who is the director of the new center. " As we

get more acceptance from third-party payers, these 80 will be done, " he

says.

" We are anticipating demand and are poised to meet it, " he says. " There

is little doubt that other centers will open as well, " he says. " Other

investigators made a conscious decision to focus their practice on

spinal arthroplasty, " he says. " Studies on a number of other artificial

disks are going on concurrently, " he adds. " The Charite is

transformational technology, and we will see much of the field

transition as other artificial disks follow. "

Others disks being developed include PRODISC-C (Synthes-Stratec/Spine

Solutions, Oberdorf, Switzerland), the MAVERICK Artificial Disc

(Medtronic Sofamor Danek Inc, Minneapolis, MN), and the Actipore

Artificial Disc Replacement System (Biorthex, Montreal, QC).

Source

Geisler F. American Association of Neurological

Surgeons and Congress of Neurological Surgeons Section on Disorders of

the Spine and Peripheral Nerves; March 17-20, 2004; San Diego, CA.

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org