To The Editor:
The paper entitled "A Prospective, Randomized Study Comparing
the Results of Open Discectomy with Those of Video-Assisted Arthroscopic Microdiscectomy"
(81-A: 958-965, July 1999), by Hermantin et al., has a serious design
flaw that leads to the erroneous conclusion that patients managed
with arthroscopic microdiscectomy "had a shorter duration of postoperative disability
and used narcotics for a shorter period" than those managed with
open discectomy.
The authors state that "[t]he arthroscopic microdiscectomy was
performed on an outpatient basis, whereas the laminotomy and discectomy necessitated
one night of hospitalization." The authors do not describe whether
the patients were offered one night of hospitalization or discharge
in both the arthroscopic and open discectomy groups. There was bias
against open discectomy because the arthroscopic group was allowed
to go home. Open discectomy can be performed on an outpatient basis1.
The patients who were treated with open discectomy received intravenous
patient-controlled morphine sulfate for twenty-four hours, followed
by the oral administration of a narcotic for a mean of twenty-five
days (range, seven to fifty-six days). Twenty percent of these patients were
still using codeine intermittently for back and buttock pain at
the time of the last follow-up. The patients who were treated with
arthroscopy did not receive any injectable pain medications, and
the mean duration of the use of oral narcotics was seven days (range,
three to fourteen days). To determine whether there is a difference
in the use of narcotics in a prospective study comparing treatment
groups, the same analgesic regimen must be prescribed to both groups.
The same orders must be written for postoperative analgesics in
both groups to determine if more pain medication is required because
of pain suffered by one group versus another. In this study, there
was bias against the open discectomy group because of the overadministration
of intravenous narcotics and of postoperative oral narcotics. The
prolonged use of narcotics in this series led to the longer duration
of postoperative disability in the open discectomy group.
Although the study design led to erroneous conclusions, it does
point out the importance of limiting the use of postoperative narcotics
in patients undergoing lumbar spine surgery, to facilitate their
rapid recovery, rehabilitation, and long-term well being.
Mark D. Brown, M.D., Ph.D.
Department of Orthopaedics and Rehabilitation
University of Miami School of Medicine
P.O. Box 016960 (R-2)
Miami, Florida 33101
E-mail address: mbrown@med.miami.edu
F. U. Hermantin, T. Peters, L. Quartararo, and P. Kambin
reply:
We appreciate the concerns of Dr. Brown. These issues were considered
and well defined at the outset of the study.
Prior to the opening of envelopes and the assignment of patients
to Group 1 or Group 2, the patients were advised that, following
the surgery, they might be discharged on the same day with oral
pain medication or, if necessary, have a one-night stay in the hospital.
In contrast to the patients who underwent open laminotomy and
discectomy (Group 1), the patients who underwent arthroscopic microdiscectomy
(Group 2) did not require injectable pain medication postoperatively.
They became ambulatory within an hour or two following their surgery.
Therefore, the intravenous line was removed and the patients were
discharged.
The same analgesic regimen was used in both groups. The patients
in Group 1 (laminotomy and discectomy ) also had access to oral
pain medication, and they were instructed not to use morphine if
the pain was controlled by oral pain medication. Invariably, the
patients required intravenous analgesics during the first twenty-four hours
following surgery.
I trust that the above information will address the concerns
of Dr. Brown.
Frank U. Hermantin, M.D.
Todd Peters, M.D.
Louis Quartararo, M.D.
Parviz Kambin, M.D.
Corresponding author: Parviz Kambin, M.D.
P.O. Box 265
Devon, Pennsylvania 19333