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SPINE Volume 27, Number 5, pp 549–553
©2002, Lippincott Williams & Wilkins, Inc.
Multiple Independent, Sequential, and Spontaneously
Resolving Lumbar Intervertebral Disc Herniations
A Case Report
Alex Reyentovich, BS,* and William A. Abdu, MD, MS†
Study Design. A case report is presented.
Objective. To highlight the potential for spontaneous
resolution of large extruded intervertebral lumbar disc
herniations in a patient with three independent
herniations.
Summary of Background Data. The most effective
methods of treatment for lumbar intervertebral disc herniations remain in question. This is partly because the
potential for intrinsic spontaneous resolution is not understood, and because many believe that large extruded
lumbar intervertebral disc herniations require surgical intervention. This case report addresses both issues.
Methods. A case is reported and the literature is
reviewed.
Results. In the patient described, multiple independent
lumbar intervertebral disc herniations resolved spontaneously both clinically and radiographically with nonoperative treatment.
Conclusions. Not only is the question concerning the
cause of disc herniation unresolved, but the best methods
of treatment also are generally unclear. This case report
documents a patient with the intrinsic capability not only
to herniate multiple lumbar intervertebral discs, but also
to resolve them clinically and anatomically. Extruded
lumbar intervertebral disc herniations may be treated
without surgery, as highlighted by this case report. The
immunohistologic pathomechanism for resorption remains unclear. [Key words: lumbar intervertebral disc
herniations, lumbar MRI, sciatica] Spine 2002;27:549 –553
Although the first reported surgery for lumbar disc herniation occurred more then 60 years ago, there still remains little consensus as to the most efficacious treatment protocol for symptomatic lumbar disc
herniation.9,16 Both surgical and nonsurgical treatments
may provide a successful outcome in appropriately selected patients. In a retrospective cohort study involving
a subgroup of patients who had lumbar disc herniations
without stenosis, Saal and Saal25 demonstrated good to
excellent results in more than 90% of the patients treated
nonoperatively. The Maine Lumbar Spine Study,4 an observational study, examined 5-year outcomes from surgical and nonsurgical management of sciatica. The study
From *Dartmouth Medical School, Hanover New Hampshire, and
†Section of Orthopaedic Surgery, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, New Hampshire.
Supported by a Harmes Surgical Scholarship.
Acknowledgment date: January 22, 2001.
First revision date: May 15, 2001.
Acceptance date: August 28, 2001.
The manuscript submitted does not contain information about medical
device(s).
No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
demonstrated a greater symptom reduction at 5-year follow-up assessment for surgically treated patients. At this
writing, only the Weber31 study has compared the surgical management of lumbar disc prolapse with nonsurgical management, demonstrating that patients undergoing discectomy had significantly better outcomes at 1
year, but no difference in outcomes at 4 or 10 years.
Despite the recent establishment of guidelines for the
treatment of acute low back problems in adults,1 and the
advent of “shared decision-making” concepts in intervertebral disc herniation,22 the best methods of treatment often remain the individual preference of the patient or the surgeon.32
Traditionally, one relative indication for surgery is a
large extruded herniation.23 Although these herniations
often have a greater severity of symptoms, they also have
shown the greatest tendency to decrease in size with nonoperative treatment.2,5,17,18,26 Recent work with immunohistologic studies has created some insight into the
reabsorptive mechanisms.7,11,13 It also has been demonstrated that these patients can be managed successfully
with nonoperative methods.15,24
This case report presents a patient who experienced
three large, independent, and sequential lumbar disc herniations over the course of 3 years. Each herniation regressed spontaneously with nonoperative management,
as demonstrated by magnetic resonance imaging (MRI),
with corresponding remission of symptoms. The patient’s clinical course and radiographic studies are
reviewed.
This case report aims to document this unique circumstance of multiple lumbar intervertebral disc herniations
and resolutions, to exemplify the ability of large herniations to resolve nonoperatively both clinically and radiographically, to demonstrate the potential for recurrent
herniations in patients treated nonoperatively, and to
raise the question about pathophysiology associated
with these issues.
Case Report
A healthy, nonsmoking 44-year-old male physician was seen
originally in May 1996 for back pain and left posterior thigh
pain. The patient’s remote history was notable for intermittent
isolated midline low back pain over the previous 10 years. The
recent pertinent history included the onset of back pain and
spasms for several weeks before presentation. His major presenting disorder was back pain and spasms, with associated
pain in the left posterior thigh. There was no numbness or
sphincter dysfunction. Neurologic examination showed weakness of the left extensor hallucis longus, rated 4 over 5 by
549
550 Spine • Volume 27 • Number 5 • 2002
Figure 1. Sequential lumbar spine magnetic resonance images. a, Sagittal T2-weighted scan (TR 3500/TE 102/3 NEX/5 mm thickness)
demonstrates a large central disc herniation at L4 –L5. Degenerative changes are apparent with increased signal on this T2-weighted scan
at adjacent endplates. b, Axial proton density scan (3500/21/2/5 mm) at L3–L4 appears unremarkable. c, Axial scan at L4 –L5 shows the
large central and left paracentral disc herniation with significant compromise at the canal. d, At L5–S1, there is asymmetry of the posterior
elements, but no apparent disc herniation.
manual motor testing. The results for the remainder of the
neurologic examination, including sensory function, reflexes,
and a straight-leg-raise test were normal.
Because of persistent symptoms, at approximately 4 weeks
from onset of symptoms, an MRI of the lumbar spine was
obtained, which showed a large intervertebral disc herniation
in the left paracentral region of the spinal canal at L4 –L5,
consistent with the patient’s left L5 radiculopathy (Figure 1a–
1d). The unusual size of the disc herniation led to administration of gadolinium to confirm the diagnosis. Of note was a
known Grade 1 Type-IIA spondylolisthesis of L5 on S1.
After a discussion of treatment options, medical management was continued, which included a course of oral steroids
followed by nonsteroidal antiinflammatory medication. Over
the next several weeks, while continuing to work, the patient’s
pain, spasms, and weakness completely resolved.
In September 1996, the patient experienced low back pain
and new onset of right leg pain in the L4 dermatomal distribution. His left leg remained completely asymptomatic. He ambulated in a squatting position, with flexion at the hips and
knees, because this was the position of comfort. At other times,
he used a wheelchair. He was always able to obtain a position
of comfort. Standing was maintained at a flexed posture of
approximately 45° of flexion. Neurologic examination results
were normal, and tension signs were absent. He continued to
pursue nonoperative treatment.
An MRI of the lumbar spine demonstrated a moderate-size
right paracentral intervertebral disc herniation at L3–L4, consistent with the patients’ clinical syndrome of an L4 radiculitis
(Figure 2a–2d). The previously demonstrated disc herniation at
L4 –L5 had completely resolved. After several additional weeks
of medical management, the right L4 radicular symptoms completely resolved.
In September 1998, new onset low back pain and right leg
symptoms developed. These symptoms were distinctly different
from the previous right-side symptoms. They were associated
with diminished sensation in the plantar aspect of the right foot
and gastrocnemius weakness manifested by an inability to toe
walk. The right Achilles deep tendon reflex was now absent.
The results from the straight-leg-raise test were negative
bilaterally.
After several weeks of persistent symptoms, an MRI of the
lumbar spine was obtained. The MRI demonstrated a large
intervertebral disc herniation in the paracentral region of the
spinal canal, inferior to the right L5 pedicle (Figure 3a–3d).
This appeared to arise from the L4 –L5 intervertebral disc space
with distal migration. The previously visualized and symptomatic intervertebral disc herniation at L3–L4 had completely resolved. After several additional weeks of medical management
with a course of oral steroids followed by nonsteroidal antiinflammatory medication for the S1 radiculopathy, the symptoms completely resolved. At this writing, the patient has remained without radicular symptoms since that time, although
he has experienced some right calf cramping and intermittent
low back pain.
In October 1999, while the patient remained asymptomatic,
an MRI of the lumbar spine was obtained to visualize the lumbar spinal canal and assess the intervertebral disc spaces and
cauda equina. The MRI demonstrated complete resolution of
the most recently symptomatic intervertebral disc herniation
Figure 2. a, The scan obtained 5 months later shows an improvement in the L4 –L5 disc, but a new L3–L4 disc herniation on the sagittal
T2-weighted scan (3500/102/3/5 mm). b, The proton density scan (3500/19/2/5 mm) now shows a right paracentral disc herniation at L3–L4.
The scan of L4 –L5 now appears essentially normal (c), as does L5–S1 (d).
Lumbar Intervertebral Disc Herniations • Reyentovich et al 551
Figure 3. a, A repeat sagittal T2-weighted study (3500/102/3/5 mm) obtained 10 months later shows a new large disc herniation arising
at L4 –L5. b, The axial proton density scan (4000/19/2/5 mm) at L3–L4 shows regression of the L3–L4 right paracentral disc. c, The scan
at L4 –L5, however, shows the new large right paracentral disc herniation, which has considerable caudal extension into the lateral recess
of L5. The axial scan at L5–S1 is normal.
from under the right L5 pedicle. There was no evidence of nerve
root compression by intervertebral disc material at any level of
the lumbar spine (Figure 4a– 4d).
Discussion
The reported patient’s case history demonstrates three
sequential, independent, and spontaneously resolving
lumbar intervertebral disc herniations. As per the patient’s choice, each event was managed nonoperatively,
and as shown on MRI, each demonstrated full remission
in both the abatement of radicular symptoms and the
anatomic resolution of the intervertebral disc
herniations.
Spontaneous reductions of lumbar and cervical disc
herniations have been described numerous
times.4,5,17,18,25,26,28 –31,33 Accompanying these reductions also has been a reduction in symptoms such as
acute back pain and sciatica. In a retrospective cohort
study, Saal and Saal25 demonstrated that lumbar disc
herniation with radiculopathy can be successfully treated
nonoperatively, with nonoperative treatment resulting in
“good to excellent” outcomes for approximately 90% of
patients. Of the 15 patients with extruded disc herniations, 11 had weakness, although the results were no
different from those for nonextruded disc herniations.
Saal and Saal25 concluded that extrusion was not an
adequate indication for surgical intervention. The study
also implied that unresponsiveness to nonoperative
treatment may suggest the presence of significant stenosis, as observed with nonresponders in the study.
Several studies of the lumbar spine using MRI have
demonstrated that the largest lumbar intervertebral disc
herniations are those most likely to show the greatest
regression in size over time.5,18 This phenomenon has
been demonstrated with cervical herniations as well.17
Although still disputed in the literature, studies have
shown that the degree of reduction in disc size, as evidenced by MRI, correlates closely with the degree of
clinical improvement.2,33 These findings on MRI, however, have been found to lag behind improvement in leg
pain.13 One recent study attempting to quantify the extent of regression necessary for clinical improvement
demonstrated a 95% success rate in cases of herniations
that regressed more than 20%. Rust and Olivero24 recently demonstrated a high success rate of approximately
71% in the use of nonoperative measures for the treatment of far lateral lumbar disc herniations. This contrasts sharply with previous opinions indicating an extremely low success rate.8
As evidenced by MRI, the reported patient’s intervertebral disc herniations were extremely large, occupying a
major portion of the spinal canal, which also is quite
large. It is possible that this contributed to an accommodation of the herniations and the nonclassic findings exhibited in this case report. Carragee and Kim6 noted that
Figure 4. a, The sagittal T2-weighted scan (2500/95/3/4 mm) obtained 13 months after the images in Figure 3 show resolution of the large
L4 –L5 disc. The axial proton density scans (2000/13/2/5 mm) at L3–L4 (b), L4 –L5 (c), and L5–S1 (d) all appear essentially normal.
552 Spine • Volume 27 • Number 5 • 2002
a small herniation in a larger spinal canal was modestly
associated with successful nonoperative treatment. This
finding could be consistent with the MRI findings in the
first and second intervertebral disc herniations. However, the mechanism by which these disc herniations resolve is still under study. Intervertebral disc herniations
act as foreign bodies in the epidural space. Several immunohistologic studies have demonstrated that the immune system attempts to remove the “invading” disc
tissue.7,11,13 Hirabayashi et al11 concluded that vessels
from the epidural fat infiltrate the disc material. Accompanying the vessels are granulation tissue and the eventual transformation into scar tissue. In an immunohistologic study, Doita et al,7 demonstrated that significant
levels of endothelial growth factor in the extruded discs,
as compared with smaller protruded discs, presumably
enhance the proliferation of endothelial cells.
These studies also have demonstrated that macrophages probably play a vital role in both resorption and
cytokine (bFGF) signaling to promote endothelial cell
proliferation and neovascularization.7 In a clinical study
of lumbar disc herniation regression using multiple linear
regression analysis, Ahn et al2 concluded that transligamentous extension of the herniation was the only significant factor contributing to the spontaneous regression
of the disc herniation. This argument has been reaffirmed
by both histologic evidence and the finding that a greater
percentage of disc herniations through the posterior longitudinal ligament contained infiltration of macrophages
than those not extruded through the posterior longitudinal ligament.12 Smaller, slower-resorbing herniations
showed significantly smaller macrophage infiltration.
As research methods continue to advance, the role
that different mechanisms play in the process of disc resorption is becoming better understood. In a recent study
by Haro et al,10 knockout mice were used to demonstrate
that macrophage induction of a chondrocyte enzyme
(matrix metalloprotienase-3) plays a key role in disc resorption through several mechanisms. Although the
pathomechanism of pain has not yet been fully elucidated, phospholipase A2 and nitric oxide are thought to
play vital roles.19,27 Individual variations in the expression of various molecules also may be found to play a
pivotal role in the natural history of intervertebral disc
herniations and one day may be a target for symptomatic
control.
Genetic factors also may play a role in the etiology of
intervertebral disc herniation. Using modern genetic
techniques, researchers have identified several putative
disease-causing variations in collagen IX, a collagen expressed in the anulus fibrous and nucleus pulposus of the
intervertebral disc.3,14,20,21 Recently, Paassilta et al20
identified a specific base pair substitution in the alpha-3
chain of collagen IX (Arg103 to Trp) that, when present,
may increase the risk of lumbar disc disease threefold.
Although these findings have little therapeutic use at this
time, discoveries such as these may one day play a role in
identifying individuals who may have increased suscep-
tibility to disorders of the intervertebral disc, or help to
determine which patients may benefit from which treatment options.
As evidenced in several studies, not all lumbar intervertebral disc herniations respond well to nonoperative
treatment.2,5,18,23,29 Carragee and Kim6 demonstrated
that response to nonoperative treatment correlates with
demographic and clinical features, whereas the outcome
for those undergoing surgery correlates with morphometric features of the disc herniation and spinal canal
seen on MRI. Of the MRI parameters evaluated by Carragee and Kim,6 only a small ratio of disc hemiarea to
remaining canal hemiarea was modestly correlated with
better outcomes (P ⫽ 0.045) in nonoperative patients.
Among the patients choosing nonoperative treatment,
some may eventually require operative intervention for
unremitting or progressive symptoms. The Weber31
study estimated this number to be as high as 25% after 1
year. In the larger Maine Lumbar Spine Study, it was
shown that by 3 months, 15% of patients initially treated
nonoperatively crossed over and underwent surgical intervention for the treatment for their intervertebral disc
herniations.4
The reported case reaffirms earlier findings demonstrating that a large lumbar disc extrusions can be managed successfully by nonoperative methods. This case is
unique in that it represents multiple independent lumbar
intervertebral disc herniations, all of which resolved
spontaneously, both clinically and radiographically.
This case report also suggests that despite the multiple
extrinsic methods used to treat lumbar intervertebral
disc herniations, the most critical factors may be those
intrinsic to the patient. Although the successful management of this patient by nonoperative treatment has been
demonstrated, many aspects of his disease process remain a mystery.
Key Points
● Multiple independent recurrent lumbar intervertebral disc herniations are uncommon.
● Extruded lumbar disc herniations can resolve
spontaneously.
● Immunohistologic mechanisms may be responsible for the resorption of lumbar intervertebral disc
herniations.
Acknowledgment
The authors gratefully acknowledge the assistance of Dr.
Alex Mamourian, Dartmouth-Hitchcock Medical Center Radiology Department, in the interpretation of the
MRI imaging studies.
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Address reprint requests to
William A. Abdu, MD, MS
Section of Orthopaedic Surgery
Dartmouth-Hitchcock Medical Center
One Medical Center Drive
Lebanon NH 03756
E-mail: [email protected]