Key-words: Deformity - expandable cage - fusion - kyphosis - osteomyelitis
Introduction
Deep infection of the spine is not an uncommon disease with various routes of dissemination
such as hematogenous seeding,[[1 ]],[[2 ]] adjacent spread,[[3 ]] or iatrogenic inoculation from spinal procedures.[[4 ]] Current treatment algorithms often involve a prolonged course of antibiotics[[5 ]] and surgical debridement with or without instrumentation of the affected spine.[[6 ]] Instrumentation in patients with spinal infections complicated by spinal deformities
has been an area of controversy given the treatment paradigm of refraining from implant
use in the infected patient population.[[7 ]],[[8 ]],[[9 ]],[[10 ]],[[11 ]],[[12 ]] There is always the theoretical risk of pathogen seeding into the implants, rendering
the infection more difficult to treat.
Spinal infections can be categorized into pyogenic and nonpyogenic.[[7 ]] Pyogenic infections typically respond well to conservative management, although
more advanced conditions such as mechanical spinal instability usually require surgical
intervention. The main concern with these pyogenic pathogens is the formation of biofilms.[[10 ]] Although this concern has been confirmed in appendicular arthroplasty surgery,[[11 ]] it has not been shown to be conclusive in spinal instrumentation.[[12 ]] In contrary to appendicular arthroplasty, spinal instrumentation actually confers
advantages to the patient when the stability of the spine is a concern despite the
risk of biofilm formation.[[7 ]],[[8 ]],[[13 ]],[[14 ]],[[15 ]],[[16 ]] Therefore, there has been a paradigm shift in the field of spinal surgery over
the past two decades, prioritizing the placement and preservation of instrumentation
whenever indicated.[[17 ]],[[18 ]]
The main indications for surgical debridement/irrigation and instrumentation include
spinal cord compression, neurologic compromise, significant deformity, spinal instability,
and failure of medical management.[[19 ]],[[20 ]],[[21 ]],[[22 ]],[[23 ]] Surgical intervention with radial debridement and instrumentation allows for maintenance
of sagittal alignment, reduction in prolonged periods of bed rest, and stabilization
of the spine. We present three cases of patients with severe and complex spinal deformities
in the setting of active osteomyelitis. The objective of this article is to highlight
the management of patients with impending or worsening spinal instability requiring
instrumentation in the setting of an active infection.
Case Series
Patient 1
Patient 1 is a 31-year-old female with a known history of intravenous drug use (IVDU),
bipolar disorder, and hepatitis C, who presented to our institution on January 10,
2018, for the evaluation of back pain. She has had T5-9 laminectomies performed at
another institution in 2016 for spinal epidural abscesses. Workup at our hospital
showed findings concerning for T5-6 osteomyelitis with significant kyphotic deformity
[[Figure 1 ]]. The patient was neurologically intact on examination. At that time, infectious
markers were elevated with a C-reactive protein (CRP) of 5.1 and erythrocyte sedimentation
rate (ESR) of 74, and the patient was started on empiric antibiotic therapy. Her current
condition was very concerning for the progression of spinal deformity; thus, the decision
was made to proceed with stabilization in the setting of active osteomyelitis. She
underwent transpedicular corpectomies at T5-6 with instrumentation and fusion from
T1 to T11 [[Figure 2 ]]. The patient remained neurologically intact postoperatively, although she was involved
in several incidents of drug paraphernalia during her hospital stay. She was discharged
on February 13, 2018, with upright X-ray images showing a stable spinal alignment
[[Figure 3 ]].
Figure 1: Patient 1. Preoperative sagittal computed tomography (a) and T2-weighted (b) images
Figure 2: Patient 1. Immediate postoperative sagittal computed tomography (a), lateral (b),
and anteroposterior (c) X-ray images after the first surgery
Figure 3: Patient 1. Upright anteroposterior (a) and lateral (b) X-ray images at 4 weeks after
the first surgery
The patient was lost to follow-up until December 7, 2019. In the interim, she presented
to another hospital on April 30, 2019, for osteomyelitis and kyphotic deformity at
T10–11, for which she had an extension of her hardware to L4 [[Figure 4 ]] and [[Figure 5 ]]. She also endorsed noncompliance with her oral antibiotic regimen and IVDU. The
patient returned to our care because of purulent discharge from exposed hardware at
the proximal end of her construct that she noticed 1–2 weeks earlier [[Figure 6 ]]. Imaging during this hospital admission showed worsening of the kyphotic deformity
and complete spondyloptosis of T9 over T11 [[Figure 7 ]], with a surprisingly intact neurological examination. Her body mass index was 14.
The patient was presented at our spine conference, and the decision was made to proceed
with surgery, again for concern of a catastrophic event if spinal stability is not
attained promptly.
Figure 4: Patient 1. Sagittal T2-weighted (a) and lateral X-ray (b) images at 10 weeks after
the first surgery
Figure 5: Patient 1. Intraoperative lateral X-ray images (a) from the second surgery performed
at 10 weeks after the first surgery. Immediate postoperative anteroposterior X-ray
(b) and sagittal computed tomography (c) images
Figure 6: Patient 1. Photograph of the patient's back on presentation at 29 weeks after the
second surgery
Figure 7: Patient 1. Sagittal computed tomography (a), lateral (b), and anteroposterior (c)
X-ray images on presentation at 29 weeks after the second surgery
She then underwent removal of previous hardware and a T10–11 transpedicular corpectomy.
An expandable cage with large endcaps spanning the full width and resting on the epiphyseal
rings of the vertebral bodies was placed in the corpectomy defect [[Figure 8 ]]. During the reduction of kyphosis, intraoperative monitoring showed a decrease
in the right lower extremity motor-evoked potential signals. The signals, however,
returned to normal by increasing the mean arterial pressure (MAP) >90 mmHg. The plastic
surgery team assisted with the closure of the incision.
Figure 8: Patient 1. Postoperative sagittal thoracic (a) and lumbar (b) computed tomography
images immediately after the third surgery
Postoperatively, the MAP was kept at >90 mmHg for 5 days, after which she returned
to baseline function in the lower extremities and was able to ambulate on postoperative
day (POD) 13. Upright X-ray images were performed in a brace and are shown in [[Figure 9 ]]. We hope that she will continue to follow-up at our clinic for continued care and
monitoring of spinal stability.
Figure 9: Patient 1. Upright lateral (a) and anteroposterior (b) X-ray images at 2 weeks after
third surgery
Patient 2
Patient 2 is a 55-year-old male with a known history of IVDU and chronic low back
pain after a motor vehicle accident in 2016, who presented to our care for the evaluation
of worsening lower back pain and a protrusion in his back when he bends forward. The
patient had a previous L1 kyphoplasty for a compression fracture in early 2017, after
which he continued to have pain, failed conservative management, and opted for surgical
intervention. In May 2017, the patient underwent a T10–L3 fusion with laminectomies
between T12 and L1 at another institution. He was then lost to follow-up.
On January 4, 2018, the patient presented to our hospital with complaints of back
pain and protruded hardware. Imaging studies revealed proximal junctional kyphosis/hardware
failure with a new compression fracture at T12 and almost complete resorption of L1.
The construct was dislocated out of the vertebral body at the cranial end on the right.
A rod fracture was also noted on the contralateral side at the inferior end of the
instrumentation [[Figure 10 ]]. There was also a concern for an underlying infection at T12, L1, and L2 vertebral
bodies, and the patient was started on broad-spectrum antibiotics at that time.
Figure 10: Patient 2. Sagittal computed tomography (a), lateral (b), anteroposterior (c), standing
lateral (d), and standing anteroposterior (e) X-ray images on presentation
The decision was made to perform a two-staged procedure. The first stage included
irrigation and debridement of infected tissue, removal of all previous hardware, attainment
of better spinal alignment with Ponte osteotomies, and placement of new posterior
instrumentation for fusion from T8 to the iliac bones. The second stage was performed
through a minimally invasive lateral retropleural/retroperitoneal approach for a 3-level
corpectomy between T12-L2 and placement of an expandable cage and a lateral plate
[[Figure 11 ]]. Hemovac drains were placed posteriorly to help with drainage of the infection.
Figure 11: Patient 2. Immediate postoperative computed tomography (a), upright lateral (b) and
anteroposterior (c) X-ray, and standing lateral (d) and anteroposterior (e) X-ray
images
Although the intraoperative neuromonitoring signals were stable throughout the surgery,
the patient woke up with a transient lower extremity weakness. Intraoperative cultures
were positive for Staphylococcus epidermidis. He was discharged from the hospital
on POD 6 on long-term antibiotic suppression therapy. He did not come back for follow-up
until May 30, 2018, where new imaging studies showed a stable construct [[Figure 12 ]]. His last office visit was at 20 months after the surgery, during which he reported
no back or leg pain, and standing scoliosis X-rays again showed stable hardware [[Figure 13 ]].
Figure 12: Patient 2. Sagittal computed tomography (a), lateral (b), and anteroposterior (c)
X-ray images at 19.5 weeks after the surgery
Figure 13: Patient 2. Sagittal computed tomography (a), standing scoliosis lateral (b), and
anteroposterior (c) X-ray images at 80 weeks after the surgery
Patient 3
Patient 3 is a 36-year-old male with a known history of IVDU and hepatitis C who presented
to our care with neck pain and fatigue. He was diagnosed with a C2–T1 epidural abscess
and C6–7 osteomyelitis in August 2019. Blood cultures were consistently positive for
Staphylococcus epidermidis. He received intravenous antibiotics at a skilled nursing
facility for 4 weeks, after which the he discontinued his oral antibiotic regime without
consulting his physician.
On presentation in October 2019, the patient was complaining of intermittent lower
extremity weakness with C8 dermatomal numbness that progressed over several weeks.
Neurological examination showed hyperreflexia in the lower extremities as well as
positive Babinski sign bilaterally. Imaging studies revealed a significant kyphotic
deformity at C6–7 [[Figure 14 ]]. Infectious disease markers were normal, with a CRP of 0.09 and ESR of 2.
Figure 14: Patient 3. Preoperative sagittal T2-weighted (a), computed tomography (b), and lateral
X-ray (c) images
He was taken to the operating room and placed in traction under intraoperative fluoroscopy
to obtain appropriate alignment before proceeding with surgery. We were not able to
reduce the kyphosis with an initial traction. The patient was then placed in prone
positioning and pedicle screws were placed between C3–5 and T1–2 bilaterally. Bilateral
Ponte osteotomies were also performed at C6–7. The patient was then flipped to the
supine positioning, a C6–7 corpectomy was performed, an expandable cage was placed
in the corpectomy defect, a plate was fixed anteriorly between C5 and C8, and the
kyphotic deformity was corrected. Then, the patient was flipped back to the prone
positioning, and the rods were applied posteriorly. Prior to all instrumentation,
cultures were taken, and the surgical sites were irrigated with copious amounts of
warm saline and bacitracin. Closed-suction hemovac drains were placed both anteriorly
and posteriorly.
X-ray images of the final construct in place were obtained [[Figure 15 ]], and the patient was started on vancomycin and ceftriaxone. None of the cultures
showed any growth. The patient had improvement in his lower extremities at discharge
with a resolution of the C8 dermatomal numbness. He is scheduled to follow-up at our
clinic in the coming months for postoperative care.
Figure 15: Patient 3. Postoperative sagittal computed tomography (a), upright lateral (b), and
anteroposterior (c) X-ray images
Discussion
The three patients of this series represent typical cases of the dilemma that surgeons
usually face in the decision-making process of whether to instrument and fuse a patient
with active spinal osteomyelitis, the goal of which is to preserve spinal alignment
or correct deformity, mitigate unrelenting pain, and prevent neurological deterioration.
In patients with primary spinal infections, there is a universal belief that instrumented
stabilization should be performed when indications are met. Contrary to guidelines
followed by other surgical fields,[[11 ]],[[24 ]],[[25 ]],[[26 ]],[[27 ]],[[28 ]] retaining, revising, or placing instrumentation in the setting of primary spinal
infection is becoming more common.[[6 ]],[[7 ]],[[8 ]],[[9 ]],[[12 ]],[[13 ]],[[14 ]],[[15 ]],[[19 ]],[[20 ]],[[21 ]],[[23 ]],[[29 ]],[[30 ]]
Epidemiologic data for spinal infections revealed an increasing incidence that appears
to coincide with an increase in IVDU and the use of immunosuppressive therapy.[[29 ]],[[31 ]],[[32 ]] The ever-changing antimicrobial resistance patterns and an increasingly sick patient
population may all play a significant role in this clinical problem. From an economic
standpoint, the cost associated with the diagnostic studies, surgical therapies, and
lost productivity time remains significant. From a patient perspective, delays in
diagnosis and care can lead to significant disability or even death.[[33 ]] Guidelines for the diagnosis and treatment of de novo spine infections are still
absent due to the lack of larger supportive studies with significant power.[[34 ]] Currently, the literature supports spinal instrumentation in immunocompromised
patients with pyogenic vertebral osteomyelitis as it is associated with a low risk
of long-term or recurrent infection.[[29 ]]
Patients 1 and 2 had previous instrumentation that required revision because of hardware
failure. However, the lesson learned from patient three who developed a cervical kyphotic
deformity is that appropriate antibiotic therapy may be able to treat the infection,
but it may not be able to prevent the development of mechanical instability. For some
patients, therefore, the benefits of spinal stabilization outweigh the potential risks
of infection relapse, reoperation, or increased overall morbidity and mortality.[[14 ]] In all the three patients, dynamic X-ray images are contraindicated preoperatively
due to the obvious instability and high risk of spinal cord injury. However, we do
obtain dynamic X-rays in these patients routinely at 3 months of follow-up to confirm
the stability of the construct. Close follow-up with ESR and/or CRP is also recommended
in the postoperative period, especially in patients with persistent infection, as
confirmed by cultures from intraoperative samples. New inflammatory markers may be
helpful in cases of inconclusive ESR and CRP levels and high clinical suspicion of
continued infection or potential sepsis.[[35 ]]
For a long time, the dogma in surgery has been to remove the hardware in the setting
of an active infection for fear of biofilm formation and the subsequent inability
to eradicate the infection; placement of new instrumentation in the setting of an
active infection at the surgical site is even less likely to be pursued.[[36 ]],[[37 ]],[[38 ]] These beliefs primarily evolved in the literature of other surgical subspecialties.[[11 ]],[[24 ]],[[25 ]],[[26 ]],[[27 ]],[[28 ]] Nevertheless, a dissenting opinion throughout the spinal surgery community has
made these two concepts controversial, where hardware removal in early infections
can cause instability and progressive deformity.[[30 ]],[[37 ]] Removing the hardware without new instrumentation would not have been appropriate
or feasible in the three patients of this series due to the severity of their deformities
and impending spinal cord injury. These three patients were fortunate to present with
the intact neurological examination; otherwise, spinal cord injury might have been
irreversible at the time of presentation. In recent years, direct spinal fixation
following debridement of both pyogenic and nonpyogenic infections has been conducted,
where fixation in conjunction with aggressive antibiotic regimens resulted in the
healing of many spinal infections.[[6 ]],[[7 ]],[[8 ]],[[9 ]],[[12 ]],[[13 ]],[[14 ]],[[15 ]],[[19 ]],[[20 ]],[[21 ]],[[23 ]],[[29 ]],[[30 ]] It is also worth noting that despite the presence of a fusion mass on imaging,
there have been cases of patients losing their spinal corrections after hardware removal.[[30 ]],[[37 ]]
Conclusion
Spinal instrumentation and fusion for correction of kyphotic deformity is sometimes
necessary in the context of active osteomyelitis and should be done emergently and
without hesitation when spinal cord injury from spinal instability is of concern.
The benefits of spinal stabilization outweigh the potential risks of infection relapse,
reoperation, or increased overall morbidity and mortality. Large controlled studies
are dearly needed to establish evidence-based guidelines related to this topic, especially
that microbial flora patterns and biofilm formation vary from center to center and
region to region, which may have some influence in the decision-making process.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms.
In the form, the patients have given their consent for their images and other clinical
information to be reported in the journal. The patients understand that their names
and initials will not be published and due efforts will be made to conceal their identity,
but anonymity cannot be guaranteed.
