To The Editor:
This letter may seem a bit long-winded. Please take the time
to consider it.
My reading of the July 1999 issue of The Journal leaves me gravely
disappointed in my profession and deserves comment to which I welcome
your reply.
The issue begins with the Editorial on "Management of Postoperative
Pain in Animals Used in Research" (81-A: 751, June 1999), by Dr.
Cowell, stating our avowed plan to keep the critters comfy. Why?
Politics, obviously. Who cares? They're mostly vermin, or food,
for crying out loud. Aren't our basic researchers already shackled
enough without this added to their burden?
Nowhere does the Editorial address the real reason that such pain
control would be important; that is, the potential effects of pain
on the behavior and biology of study animals that could be a powerful
confounder in the animal studies' extrapolation.
The same issue contains a Current Concepts Review on "Interbody
Fusion Cages in Reconstructive Operations on the Spine" (81-A: 859-880,
June 1999), by P.C. McAfee, ostensibly with the mission of presenting
an improved care option for our human patients.
In this review, the author (who presents a "received benefits" waiver-where
is editorial objectivity here?) quotes three references1-3 to suggest
that ". . . the high rate of failure . . . of posterior pedicle-screw
instrumentation . . ." presents cages as (safe and effective?) the
best thing since sliced cheese and concludes that clinical trials' arthrodesis
rates of 91% to 96% mean that every backache should be caged.
As orthopaedists, we are taught to support technology and we
are paid for operating on people. We are not generally taught to
critique our results or the literature (editorial boards are supposed
to do that for us; hence this appeal).
Many spinal surgeons in clinical practice have great concerns about
cages, which the recent review fails to address.
Let's put cages in context. Why are they here? Because pedicle screws
don't work? No. Of the review references suggesting this1-3, only
one is not an article about cages1, and it is almost a decade old!
The text of the review itself quotes arthrodesis rates with simple
pedicle-screw instrumentation as high as 95% in one article4 and
largely ignores the many similar series published in the past ten
years5-12.
Cages are here because of the pedicle-screw lawsuit, pure and simple.
Lawyers and the Food and Drug Administration made it difficult for
pedicle screws to be used widely in the United States some years
ago. Cages were driven in to fill this void created by the industry
that had formerly promoted pedicle screws in the marketplace. Do
cages consistently cause fusion? We don't know. The review admits
as much in discussing the difficult and inconsistent definition
of radiographic fusion.
Are cages safe? Hmm. The review admits a 1% frequency of disc
displacement causing sciatica in the expert hands of the Food and
Drug Administration trials' leaders. The 1998 North American Spine
Society program suggests this may be as much as a 5% to 10% probability.
Is this acceptable? I've never heard of it in a pedicle-screw case.
I would not subject my patient to it, short of extraordinary circumstances.
Are cages safe? Hmm. The review suggests a vascular injury rate
in expert hands of 1%. (If it's so rare, why does the review have
to discuss modified [lateral] surgical approaches to improve cage
safety?) Again, the recent North American Spine Society program
suggests that an injury rate of 5% to 10% is more like it. My hospital
has had two active pedicle-screw surgeons for over a decade, with
no vascular complications. We have had a cage surgeon for less than
a year. Already, one middle-aged patient has gone on to aortobifemoral bypass
with compartment syndrome and a Volkmann contracture requiring surgical
release after aortic thrombosis. How are these risks explained to
the patient? I can't imagine explaining this to a Canadian malpractice
lawyer, much less an American one. Where do these cases appear in
the analysis of the supposed economic benefits of caging?
Do cages relieve back pain due to degenerative disc disease? This
key question, really the only question, is not addressed at all in
this review!
I do not believe that The Journal has served
its readership, or the public, very well at all here.
I'd like to make three suggestions. First, Current Concepts Reviews
should not be sought from those with a vested interest in the evolving
technologies presented. Second, the editors might more critically
review what is to be presented between the august covers of The
Journal. Third, the editors should consider presenting
short critiques of the more important articles, perhaps along the
lines of the "Point of View" series in Spine, and getting them from
people with some basic skills in critical literature review and
without a vested interest in either the support or detraction of
the technologies presented.
The Editorial suggests the animal rights lobby can affect what is
presented in The Journal. Who lobbies for our patients? The
editors must!
-Drew A. Bednar, MD293 Wellington Street North, Suite 102
Hamilton, ON L8L 8E7, Canada
T.A. Einhorn replies:
Dr. Bednar has written concerning two recent publications in The
Journal: an Editorial regarding the management of postoperative
pain in animals used in research and a Current Concepts Review concerning
the use of interbody fusion cages in reconstructive operations on
the spine. With respect to his comments regarding the Editorial,
Dr. Bednar asks why we should care if experimental animals feel
postoperative pain, particularly when they are "mostly vermin, or food."
He suggests that our reason for caring has to do with politics and
that the need to be politically correct in this regard is obvious.
On this point, I, and most investigators in the research community,
would take great exception. Although investigators have a need to
perform certain experiments on laboratory animals in order to test
critical hypotheses for potential applications in human medical
care, we do so while showing great respect for the laboratory animals
and ensuring their proper care and use. No living creature should
be required to endure pain unnecessarily, and the extent to which
such pain is limited is the responsibility of the investigator.
This commitment to the humane treatment of animals must hold true
regardless of whether the animal is a rat or a primate.
Dr. Bednar raises several concerns regarding the Current Concepts
Review on interbody fusion cages. His first point is that the purpose
of publishing the Current Concepts Review is "ostensibly with the
mission of presenting an improved care option for our human patients." As
Deputy Editor for Current Concepts Reviews, I differ with this assumption
only slightly. The purpose of publishing Current Concepts Reviews
is to provide the readership with a comprehensive, fair, and even-handed
overview of a topic, presenting the existing knowledge on the pathophysiology,
diagnosis, and treatment of prevalent orthopaedic conditions or
the development of current and future orthopaedic technologies. Certainly,
anything we do as orthopaedic surgeons should lead to an enhancement
of patient care, but the purpose of a review article is to provide objective
information. Dr. Bednar expresses concern that the author disclosed
that he had "received or will receive benefits for personal or professional
use from a commercial party related directly or indirectly to the
subject of this article." Dr. Bednar suggests that by allowing authors who
disclose such information to publish in The Journal, we negate our
editorial objectivity. Here, I strongly differ with his opinion.
Frequently, clinicians and scientists with the greatest expertise
in a given area of musculoskeletal disease or treatment provide
their services as consultants, investigators, or inventors to commercial
parties. Without such exchange of intellectual property, it would
be difficult to understand how many orthopaedic technologies could
be advanced. Companies cannot develop new treatments without the
input of clinicians, and clinicians who provide their time and knowledge
deserve appropriate remuneration. Indeed, it is the responsibility
of The Journal to ensure that authors conduct themselves in an ethical
and objective way and to prevent them from using the publication as
a means for promoting their own commercial interests. This is most
definitely the job of the editorial staff, but disclosure, such
as the use of statements made at the beginning of the article in
question, is part of the process.
Dr. Bednar makes other statements that I believe are incorrect. First,
he suggests that the author's assertion that clinical trials with
fusion cages show arthrodesis rates of 91% to 96% means that "every
backache should be caged." The author definitely did not say this
in the article, and that is strictly an assumption made by Dr. Bednar. Second,
Dr. Bednar's assertion that "cages are here because of the pedicle-screw
lawsuit, pure and simple" is a statement that I find difficult to
substantiate. He goes on to say that the author does not state whether
cages cause fusion consistently and that the review admits this
in discussing the difficult and inconsistent definition of radiographic fusion.
On this point, it should be noted that a Current Concepts Review
is intended to provide current knowledge on a subject, which includes
informing the readership about what is not known in addition to
what is.
Dr. Bednar seems particularly concerned regarding safety with respect
to the use of spinal implants. This is a very appropriate concern.
He asks, "Are cages safe?" He notes that the review describes a
1% frequency of disc displacement causing sciatica and a 1% rate
of vascular injuries, and then he relates an anecdote concerning
a patient who sustained an aortic thrombosis leading to a compartment
syndrome allegedly caused by the use of a spinal fusion cage. (Frankly,
I am a bit unclear regarding the mechanism of disease here, but
I take Dr. Bednar at his word.) Neither the Current Concepts Review
nor The Journal is prepared to make statements concerning the safety
of spinal fusion cages at this time. Again, it is the purpose of
the Current Concepts Review to provide objective information. Dr. Bednar
suggests that the frequency rates of 1% for the two complications
mentioned above is not accurate, as the 1998 North American Spine
Society program included articles showing rates of 5% to 10% for
each of these complications. It is important to note that The Journal
does a very thorough job of reviewing the references that authors
use to cite the statements made in their articles. Right or wrong,
the information in Dr. McAfee's Current Concepts Review is based
on articles that have been peer-reviewed and published as full-length
manuscripts. Non-peer-reviewed presentations or abstracts made at national
or international meetings are not considered acceptable for inclusion
in The Journal, and single-patient anecdotes provide little in the
way of critical information.
The Current Concepts Review certainly was not written as a direct
comparison of the use of spinal fusion cages and pedicle screws.
Why Dr. Bednar suggests this is unclear to me. It is my understanding
that spinal fusion cages are used to enhance spinal arthrodesis
when a bone graft is used. It is also my understanding that pedicle-screw
fixation is a technology used to enhance stability in the spine.
Finally, Dr. Bednar makes several suggestions that are worthy of
consideration. I have already addressed the recommendation that
Current Concepts Reviews not be sought from those with a vested
interest in evolving technologies. I certainly agree that a vested
interest should not be a reason for seeking authorship from an individual,
but if individuals with specific expertise have been involved in
a technological development, that certainly should not deter The Journal
from inviting them to submit thoughtful articles. Again, it is the
responsibility of all involved, the author, the editors, and the
readers, to conduct themselves in a scientifically ethical way and
to ensure full disclosure of any conflicts of interest. Dr. Bednar
suggests that the editors might more critically review what is to
be presented between "the august covers of The Journal."
We thank Dr. Bednar very much for his recommendation. The suggestion
that The Journal consider presenting short critiques on more important
articles, or establish a "Point of View" series, is worthy of our consideration.
Indeed, this has succeeded for other journals, and as The
Journal of Bone and Joint Surgery continues to review and
update its publication strategy, this type of input is very much
appreciated.
Dr. Bednar ends his letter by asking, "Who lobbies for our patients?"
Indeed, all of us who practice medicine must lobby for our patients.
We must protect our patients' rights by providing the highest-quality
medical care, we must acquire new information in the most scholarly
way, and we must strive to make clinical decisions based not on
inference or opinion but on scientific knowledge.
-Thomas A. Einhorn
Deputy Editor for Current Concepts Reviews
The Journal of Bone and Joint Surgery
P.C. McAfee replies:
Some innovations in orthopaedic surgery are the product of the
National Institutes of Health-sponsored research in university "academic"
training institutions, and some develop from innovative surgeons
working in community-based hospitals. The greatest single advance
in general surgery in the last twenty years, laparoscopy and endoscopic
minimally invasive technique, started in community-based surgical
environments. The first report of laparoscopic cholecystectomy and
early development of laparoscopic surgical techniques evolved from pioneers
largely in private practice13.
In a similar fashion, the major ideas and developments for lumbar
interbody fusion cage technology were initiated by surgical pioneers
working with small groups or advisory panels of surgeons out of
community-based private-practice environments: George Bagby, MD,
Steve Kuslich, MD, Charles Ray, MD, and John Brantigan, MD, to name
a few. It is my belief that the fact that this technology has been
further refined by larger international champions of industry, such
as Johnson and Johnson, Tyco International, and Medtronic, does
not diminish the contributions made by those surgeons, scientists,
or innovators who developed cage technology (listed in the 110 references
of the article). To find answers to clinical problems, it is often
very productive to attend industry-sponsored seminars where commercially
employed engineers hear about complications. The more successful,
better managed, and more responsive companies are those that ultimately
modify their products and make decisions in conjunction with surgical
advisors, based on what is best for the patient. The undeniable
fact that these investigators have a vested interest in their invention
reflects simply the hard reality that it costs money to perform
research.
The criticism that complications were deemphasized in the Current
Concepts Review is not justified-in fact, the complication section
extends from page 869 to the top of page 873. With anterior retroperitoneal
approaches to the lumbar spine, vascular complications such as the
one mentioned by Dr. Bednar occur in fewer than 1% of cases. Particularly
with surgery on elderly patients, recognizing that mobilization
of the great vessels is necessary to gain access to the anterior
aspect of the lumbar spine, it is useful to place a pulse oximeter
on the patient's great toe. Perhaps the first warning sign, and
prevention of a vascular disaster and ensuing lower-extremity compartment
syndrome, is recognizing a decrease in the oxygen saturation (pulse oximeter)
by monitoring the patient's lower extremities intraoperatively.
In a high-risk patient, stretching of the left iliac artery and
vein apparently can be detected by intraoperative placement of a
pulse oximeter on the patient's left great toe-a noninvasive monitoring
technique.
Dr. Bednar states that the 1998 North American Spine Society program
suggests as much as a 5% to 10% probability of disc displacement
causing sciatica. It is actually my presentation, published in Spine,
that is being misquoted14. The important message is taken from the
conclusion section, which applies to the overwhelming majority of surgical
complications of interbody fusion cage devices. All twenty cages
failed because of surgical technique rather than because of an intrinsic
defect in fusion cage technology. The factors associated with failure
of the original insertion procedure were (1) failure to achieve
adequate distraction of the annulus fibrosis, (2) undersized cages,
especially via the PLIF (posterior lumbar interbody fusion) graft approach,
(3) cerebrospinal fluid leakage or meningocele, (4) type-II diabetes,
(5) the use of local bone graft rather than iliac crest graft inside
the cage, (6) anterior insertion in an excessively lateral position
resulting in symptoms of a far lateral disc herniation, and (7)
failure to identify the spinal midline during an anterior approach.
It is important to remember that these are all complications that
the operative surgeon can control and reduce.
Lastly, the somewhat unconventional comments pertaining to animal
use and research were not directed to my contribution in The Journal,
but I am compelled to comment because, while a full-time member
of the Orthopaedic Department, I used the most survival animals
in the Johns Hopkins Hospital. Currently, the bulk of our animal research
is performed in the Thomas B. Morris Surgical Facility, which is
approved by the American Association for the Accreditation of Laboratory
Animal Care. It has been said that a civilization can be judged
by how well it treats its animals. The people in our laboratory
treat the animals ethically and conscientiously, with as much care
and compassion as we treat our own patients. We have visitors to
our laboratory from all over the world, and it serves as good diplomacy
for them to observe our high regard for the ethical treatment of
animals. We take our commitment to research and the ethical treatment
of animals seriously, and, hopefully, this is reflected in our clinical
as well as our basic-science research.
-Paul C. McAfee, MD7505 Osler Drive, Suite 104 Baltimore, MD 21204