ABSTRACT
ABSTRACT
Study design: A case report.
Objective: Pyogenic osteomyelitis is the most common form of vertebral infection and typically
resolves following conservative treatment with antibiotics administered long term
and immobilization. In cases of spinal instability, severe neurological deficit or
disease refractory to medical management, neurosurgical intervention is warranted.
Historically, these patients have undergone radical vertebral debridement and grafting
with or without posterior instrumentation. We report the case of a 46-year-old female
intravenous drug user presenting with L5 pyogenic osteomyelitis with L5 vertebral
compression and cortex retropulsion following L2 – L4 laminectomy for epidural abscess
8 weeks prior.
Methods: The patient underwent an anterior approach single-stage L5 corpectomy, L4/5 and L5/S1
discectomies, expandable titanium-cage insertion and anterior plating from L4 to the
sacrum.
Results: The patient recovered without any complications. The infection was successfully eradicated
and her fusion remains solid 18 months postoperatively.
Conclusions: To our knowledge, this is the first case of L5 vertebral osteomyelitis treated with
a single-stage corpectomy and anterior instrumentation.
INTRODUCTION
INTRODUCTION
Although pyogenic osteomyelitis is the most common form of vertebral body infection,
pyogenic vertebral osteomyelitis only accounts for 2 – 4% of all bone infections [1]. While antibiotics given long term are considered the mainstay of treatment, surgical
intervention is necessary in cases of neurological compromise, unstable mechanical
deformity, intractable pain, or progressive disease refractory to maximal medical
management. Recent studies have shown that surgical therapy is indicated in up to
57% of patients with pyogenic vertebral osteomyelitis, a rate much higher than previously
believed [2], [3], [6], [7]. In cases of vertebral osteomyelitis requiring surgery, L5 is affected only 4 – 9%
of the time [4], [5], [6], [7].
The surgical technique most commonly reported for the treatment of L5 osteomyelitis
is single-stage anterior debridement and stabilization with a titanium mesh cage and
posterior instrumentation [5], [6], [7]. We describe the case of a 46-year-old woman with a history of L2 – L4 laminectomy
for epidural abscess presenting with L5 vertebral osteomyelitis secondary to a new
pathogen. The patient underwent a single-stage L5 corpectomy, L4/5 and L5/S1 discectomies,
insertion of an expandable titanium cage, and application of an anterior plate from
L4 to S1 via an anterior approach. To our knowledge, this is the first case of L5
vertebral osteomyelitis treated surgically with an anterior approach, single-stage
corpectomy with anterior instrumentation.
CASE REPORT
A 46-year-old woman was transferred from an outside hospital secondary to liver failure
and altered mental status following acetaminophen overdose. Her medical history was
significant for intravenous drug abuse, hepatitis C, bipolar disorder, schizophrenia,
and the recent onset of sciatica. Initial neurological examination was limited by
mental status. She was able to follow commands and move fingers and toes bilaterally
but unable to generate any more proximal movements. She was hypotonic with decreased
rectal tone. Sensation appeared intact. The patient had extensive edema and subcutaneous
abscesses in all four extremities. Further workup revealed an L2 to L4 epidural abscess,
which was likely responsible for her neurological compromise. Subsequently the patient
underwent an urgent decompressive L2 – L4 laminectomy. Intraoperative cultures were
positive for methicillin-sensitive Staphylococcus aureus. Intravenous antibiotic therapy was started. Postoperatively her mental status and
strength improved significantly. Once she remained afebrile with adequate pain control,
she was discharged to a long-term care facility for inpatient rehabilitation and continued
intravenous antibiotic therapy.
Approximately 2 months later, the patient was transferred again to our institution
with severe lower back pain in addition to combined vancomycin-resistant enterococcus
and Citrobacter freundii bacteremia. On examination, the patient was neurologically intact with brisk reflexes noted
bilaterally in the lower extremities. She was able to stand but refused to walk secondary
to pain. The lumbar incision wound was well healed; mild fluctuance was present bilaterally
in the paraspinous region. Lumbar magnetic resonance imaging identified destructive
changes from osteomyelitis at L4 – L5 resulting in secondary compression of the L5
vertebral body with retropulsion of the posterior cortex. Extensive epidural soft
tissue was also noted from L4 to S2, causing both central canal and right neuroforaminal
stenosis from L4 to S1. Marrow edema was seen at L4 and L5 (Fig [1]). Computed tomography of the lumbar spine showed L4/5 discitis with extensive bony
destruction of adjacent L4/5 end plates and collapse of L5 (Fig [2]). A biopsy of the L5 vertebral body revealed chronic osteomyelitis.
Given the progression of the patient’s infection despite antibiotic treatment, collapse
of the L5 vertebral body and extensive scar formation, the decision was made to perform
an L5 corpectomy and fusion using an expandable titanium cage and titanium plate with
an anterior-only approach. Anterior dissection revealed an inflammatory mass around
the anterior aspect of the vertebra with the vessels tightly adherent to it. After
careful dissection, the left common iliac artery and vein were freed. Discectomy of
L4/5 and L5/S1 was performed in addition to L5 corpectomy with nearly complete removal
of the L5 vertebral body. An expandable titanium cage filled with demineralized bone
matrix and allograft was used to reconstruct the L5 vertebral body. A titanium plate
was then inserted under the iliac vein from L4 to S1 and secured with screws at S1
and L4. Postoperative imaging showed that all instrumentation was in place. Intraoperative
cultures did not isolate any organisms. Overall the patient tolerated the procedure
well without any complications.
After surgery it was determined the infection was largely controlled, and the patient
was discharged and given oral antimicrobial therapy. She was followed-up 18 months
after discharge and has done fine without any recurrence of infection. Follow-up lumbar
computed tomography shows solid fusion from L4 to S1 with good lumbar lordosis and
no evidence of lumbar stenosis (Fig [3]).
Fig 1 T1-weighted sagittal postcontrast magnetic resonance imaging shows L5 osteomyelitis
with disc space and vertebral body enhancement, as well as collapse of L5. Postoperative
laminectomy is also evident.
Fig 1 T1-weighted sagittal postcontrast magnetic resonance imaging shows L5 osteomyelitis
with disc space and vertebral body enhancement, as well as collapse of L5. Postoperative
laminectomy is also evident.
Fig 2 Sagittal reformatted computed tomography shows collapse of L5, as well as previous
laminectomy.
Fig 2 Sagittal reformatted computed tomography shows collapse of L5, as well as previous
laminectomy.
Fig 3 Postoperative computed tomography shows reconstruction of L5 with titanium cage and
restoration of lordosis.
Fig 3 Postoperative computed tomography shows reconstruction of L5 with titanium cage and
restoration of lordosis.
DISCUSSION
DISCUSSION
Pyogenic osteomyelitis is the most common form of vertebral body infection. Conservative
treatment with antibiotics administered long term and immobilization is usually sufficient
but cases of spinal instability, severe neurological deficit or disease refractory
to medical management warrant neurosurgical intervention [1], [2], [3]. Recent studies have demonstrated that radical anterior debridement and stabilization
with a titanium cage and posterior instrumentation is an effective surgical treatment
for vertebral osteomyelitis of the lumbar spine [5], [6], [7] [8]. However, L5 involvement requiring corpectomy is exceedingly rare. Lu et al [7] reported the highest incidence of spinal osteomyelitis affecting L5; seven of 36
patients had L5 involvement and underwent L5 corpectomy with posterior instrumentation.
Korovessis et al [5] reported one anterior L5 corpectomy with posterior instrumentation for further stabilization
of 24 cases reviewed. In a series by Kuklo et al [6], two of 22 osteomyelitis cases were treated with L5 corpectomy with insertion of
a mesh cage and posterior instrumentation. Risks associated with the combined anterior
and posterior approach include increased morbidity related to prolonged anesthesia
and operative time, as well as additional blood loss and tissue damage. Although the
literature has demonstrated that posterior instrumentation is an effective method
of stabilization after L5 corpectomy, a posterior approach was unfavorable in this
case due to massive scar formation and the partial deficiency of posterior elements
after extensive debridement during the first operation.
The challenge of preserving lumbar lordosis is also an important consideration when
attempting to provide stability after L5 corpectomy. Approximately two-thirds of lumbar
lordosis is created by the discs at L4/5 and L5/S1, both of which were removed in
this case due to infection and subsequent vertebral body compression [9]. In the case presented, an expandable titanium cage was selected to aid in the reconstruction
of the anterior column.
Studies have recently examined the role of expandable titanium cages in the treatment
of spinal osteomyelitis. Liljenzvist et al [10] reported promising results in the treatment of 20 patients with vertebral osteomyelitis
treated with single-stage posterior instrumentation and fusion with anterior debridement
and decompression. The anterior column was reconstructed using expandable titanium
cages filled with morsellised autogenous bone graft. In the 18 cases involving the
lumbar spine, lordosis was significantly corrected at follow-up. There was no evidence
of cage dislocation, migration, or subsidence noted in any case, and all infections
were eliminated. In a review of 36 cases of vertebral osteomyelitis treated with corpectomy
and anterior column reconstruction with an expandable titanium cage, an anterior stand-alone
corpectomy and reconstruction was performed in only five cases [7]. Most patients underwent combined anterior and posterior approaches, including the
seven patients with some degree of L5 involvement. In an effort to preserve lordosis,
the authors used an expandable titanium cage typically reserved for the thoracic spine
and placed the cage so that the curve corresponds with lumbar lordosis rather than
thoracic kyphosis. The study concluded that expandable cages with allograft have a
low rate of recurrent infection and are both safe and effective in patients with pyogenic
vertebral osteomyelitis requiring surgery [7].
An anterior approach is preferred in the surgical treatment of pyogenic vertebral
osteomyelitis as it allows for adequate debridement and reconstruction of the affected
tissue, which is almost always anterior to the spinal canal [11], [12]. Following debridement and reconstruction, the use of posterior instrumentation
is a logical choice as the infectious process in this field is believed to be controlled.
The success of anterior insertion of titanium cages eases the concern of placing metallic
constructs into an infected area, making anterior plating a viable option. A prospective
series by Dia et al [4] has demonstrated that anterior plating was effective treatment for 22 patients with
pyogenic vertebral osteomyelitis in both the thoracic and lumbar spine. In these cases,
corpectomies and discectomies were performed, and then followed with bone strut autografts
or titanium mesh cages for anterior fusion. Each patient was then treated with anterior
spinal plating using titanium Z-plate instrumentation extending one level above and
below the affected vertebrae. Solid fusion was achieved and the infection was successfully
eradicated in all cases [4]. However, none of these cases had any L5 involvement requiring corpectomy. Other
case reports have also demonstrated success with anterior instrumentation in the setting
of osteomyelitis; however, these case series were small and less than five patients
per series had lesions in the thoracolumbar spine [12], [13], [14] [15], [16]. Although single-stage anterior corpectomy with anterior instrumentation has been
successful in vertebral osteomyelitis, concerns regarding the placement of hardware
into an infected field remain [17], [18], [19]. Considering the most recent data supporting anterior instrumentation and the limited
surgical options for this patient, the decision was made to perform the anterior debridement
with L5 corpectomy, L4/5 and L5/S1 discectomies, and place an anterior titanium plate
extending from the body of L4 to S1, rather than the combined anterior and posterior
approaches.
CONCLUSION
CONCLUSION
Single-stage treatment of L5 osteomyelitis consisting of anterior L5 corpectomy, anterior
column reconstruction with an expandable titanium cage, and anterior titanium plate
has been a safe and effective treatment for our patient. At 18 months follow-up, she
remains solidly fused without any recurrent infection. By using this anterior-only
technique, the risks associated with prolonged operative time, greater blood loss,
and additional tissue damage seen in an anteroposterior surgery could be decreased.
This indicates the possibility of an anterior-only approach as a safe and effective
alternative to the traditional method of anterior debridement with insertion of a
titanium mesh cage plus posterior instrumentation in patients with vertebral osteomyelitis
requiring L5 corpectomy.