Updated: 6/24/2021

Adult Pyogenic Vertebral Osteomyelitis

Review Topic
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  • summary
    • Adult Pyogenic Vertebral Osteomyelitis, also known as spondylodiskitis, represents a spectrum of spinal infections including discitis, epidural abscess, and vertebral osteomyelitis.
    • Diagnosis is made with MRI studies with contrast. 
    • Treatment may be long-term targeted antibiotics alone or surgical decompression and stabilization depending on the extent and chronicity of infection, location in the spine, and identification and succeptibility to antimicrobials of the pathogen.
  • Epidemiology
    • Demographics
      • usually seen in adults (median age for pyogenic osteomyelitis is 50 to 60 years)
    • Anatomic location
      • 50-60% of cases occur in lumbar spine
      • 30-40% in thoracic spine
      • ~10% in cervical spine
    • Risk factors include
      • IV drug abuse
      • diabetes
      • recent systemic infection (UTI, pneumonia)
      • malignancy
      • immunodeficiency or immunosuppressive medications
      • obesity
      • malnutrition (serum albumin < 3 g/dL indicative of malnutrition)
      • trauma
      • smoking
  • Etiology
    • Pathophysiology
      • pathogens
        • bacterial
          • staph aureus
            • most common (50-65%)
          • staph epidermidis
            • is second most common cause
          • gram negative infections
            • increasing over last decade and often associated with gram negative infections of the GU and respiratory tract
        • pseudomonas
          • seen in patients with IV drug use
        • salmonella
          • seen in patients with sickle cell disease
        • tuberculosis
      • inoculation
        • hematogenous seeding
          • generally agreed that inoculation likely occurs through hematogenous seeding (arterial or venous) of the endplates and intervertebral discs
            • endplates contain area of low-flow vascular anastomosis that may provide an environment suited for inoculation
            • involvement of one endplate leads to direct extension into intervertebral discs, followed by direct extension into the second endplate
        • direct inoculation
          • can occur after penetrating trauma, open fractures, and following surgical procedure
        • contiguous spread from local infection
          • most commonly associated with retropharyngeal and retroperitoneal abscesses
      • neurologic involvement
        • neurologic deficits present in 10-20%
        • results from
          • direct infectious involvement of neural elements
          • compression from an epidural abscess
          • compression from instability of the spine
    • Associated conditions
      • epidural abscess
        • defined as a collection of pus or inflammatory granulation tissue between dura mater and surrounding adipose tissue
        • epidemiology
          • usually associated with vertebral osteomyelitis
          • present in ~18% of patients with spondylodiskitis
          • 50% of patients with an epidural abscess will have neurologic symptoms
      • psoas abscess
  • Presentation
    • History
      • history of UTI, pneumonia, skin infection, of organ transplant are common
    • Symptoms
      • fever is only present in 1/3 of patients
      • pain
        • pain is often severe and insidious in onset
        • pain is usually worse with activity and unrelenting in nature
        • pain that awakens patients at night should raise concern for malignancy and infection
      • neurologic symptoms present in 10-20%
        • radiculopathy
        • myelopathy
    • Physical exam
      • perform careful neurological exam
  • Imaging
    • Radiographs
      • findings are usually delayed by weeks
      • findings include
        • paraspinous soft tissue swelling (loss of psoas shadow)
          • seen if first few days
        • disc space narrowing and disc destruction
          • seen at 7-10 days
          • remember disc destruction is atypical of neoplasm
        • endplate erosion or sclerosis seen at 10-21 days
        • local osteopenia
    • CT
      • useful to show bony abnormalities, abscess formation, and extent of bony involvement
    • MRI
      • MRI with gadolinium contrast
        • indications
          • gold standard for diagnosis and treatment
        • sensitivity and specificity
          • most sensitive (96%) and specific (93%) imaging modality for diagnosis of spinal osteomyelitis
          • also most specific imaging modality to differentiate from tumor
        • timing
          • if performed early, finding may be interpretted as degenerative changes
            • repeat MRI to see progression may be required
        • findings include
          • paraspinal and epidural inflammation
          • disc and endplate enhancement with gadolinium
          • T2-weighted hyperintensity of the disk and endplate
            • rim enhancing
    • Bone scan
      • Technetium Tc99m bone scans
        • indications
          • patients who can not obtain an MRI
        • sensitivity and specificity
          • 90% sensitive but lack specificity
          • combined Technetium Tc99m and gallium 67 scan is both more specific and more sensitive than Technetium Tc99m alone
      • indium 111 labeled scan
        • not recommended due to poor sensitivity (17%)
  • Studies
    • Laboratory
      • WBC
        • elevated only in ~ 50%
        • not a sensitive indicator for early infection
      • ESR
        • elevated in 90% of cases
        • can be monitored serially to track success of treatment, however is considered less reliable than CRP
      • CRP
        • elevated in 90% of cases
        • can be monitored serially to track success of treatment and is considered more reliable than ESR
      • blood cultures
        • indications
          • all patients prior to antibiotic administration if organism unknown
          • identification of organism is mandatory for treatment
        • sensitivity & specificity
          • least invasive method to determine a diagnosis
          • ~33% (reports show 25%-66%) of patients with spondylodiskitis have positive blood cultures
          • when positive 85% are accurate for isolating the correct organism
          • blood culture yield is improved by withholding antibiotic and obtaining cultures when patient is febrile
    • CT guided biopsy
      • indications
        • in patients who do not have indications for immediate open surgery and blood cultures are negative
      • sensitivity & specificity
        • can provide diagnosis in 68-86% of patients
      • technique
        • can be guided by fluoroscopy or by CT scan
        • cultures should be sent for
          • aerobic
          • anaerobic
          • fungal
          • acid-fast cultures
    • Open biopsy
      • indications
        • when tissue/organism diagnosis can not be made with noninvasive techniques
      • technique
        • anterior, costotransversectomy, or transpedicular approach used
  • Differential
    • Spinal tumors
      • MRI is the most specific imaging modality to differentiate from tumor
        • features that weigh towards an infection include
          • disc space involvement
          • end-plate erosion
          • significant inflammation
  • Treatment
    • Nonoperative
      • immediate broad spectrum antibiotics
        • indications
          • critically ill patient who are septic
            • obtain gram stains and cultures first then start abx
              • consider immediate CT guided aspiration prior to administration of IV abx
          • will not be able to wait for culture results before starting broad spectrum abx
        • technique
          • vancomycin +
            • for pencicillin-resistant and gram-positive bacteria
          • third-generation cephalosporin
            • for gram-negative coverage
      • organism-specific antibiotic for 6-12 weeks +/- bracing
        • indications
          • lumbar vertebral osteomyelitis
          • organism must be identified and sensitive to antibiotics
          • controversial - some argue surgical debridement needed
        • bracing
          • helps improve pain and prevent deformity
          • rigid cervicothoracic orthosis or halo required for cervical osteomyelitis
        • antibiotics
          • indications
            • once organism has been identified via blood culture or biopsy
          • technique
            • usually treated with IV culture directed antibiotics until signs of improvement (~ 4-6 weeks) and then converted to PO antibiotics
          • resistant strains
            • new antibiotic-resistant strains of microorganisms are becoming more common and failure to diagnose can have negative consequences
            • organisms include
              • MRSA (methicillin-resistant Staph aureus)
              • VRSA (vancomycin resistant Staph aureus)
              • VRE (vancomycin resistant enterococcus)
            • treatment
              • newer generation antibiotics for antibiotic resistant organisms include linezolid and daptomycin
        • outcomes
          • successful in 80%
    • Operative
      • open biopsy alone
        • indications
          • cultures and CT guided biopsy fail to provide pathogen
          • lumbar disease without abcess formation in canal
        • technique
          • can use transpedicular (kyphoplasty-like) approach
      • neurologic decompression, surgical debridement, and spinal stabilization
        • indications
          • cervical vertebral osteomyelitis
          • progressive neurologic deficits
          • progressive deformity & gross spinal instability
          • refractory cases
          • large abscess formation
        • technique
          • dictated by characteristics of pathology
            • anterior debridement and strut grafting, +/- posterior instrumentation
              • considered to be gold standard
            • posterior debridement and decompression alone
              • usually ineffective for debridement
              • may be indicated in some cases
  • Techniques
    • Anterior debridement and strut grafting, +/- posterior instrumentation
      • goals
        • identify organism
        • eliminate infection
        • prevent or improve neurologic deficits
        • maintain spinal stability
      • techniques
        • strut graft selection
          • autogenous tricortical iliac crest, rib, or fibula strut grafts have proven safe and effective in presence of acute infection
          • allograft being used with good results, but autogenous sources theoretically have better incorporation
          • a recent study showed improved deformity correction with titanium mesh cages filled with autograft (followed by posterior instrumentation)
        • instrumentation
          • spinal instrumentation in presence of active infection is controversial
            • some advocate I&D followed by staged instrumentation
            • some advocate a single procedure with bone graft and instrumentation in the presence of an active infection
          • titanium is preferred over stainless steel
        • posterior instrumentation
          • posterior instrumentation indicated when severe kyphotic deformity or a multilevel anterior construct required
          • posterior instrumentation can be performed at same time or as a staged procedure

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(OBQ17.113) Of the magnetic resonance images provided in Figures A-E, which circumstance would be most indicated for anterior and posterior approaches with spinal stabilization and fusion? The primary symptoms on presentation are described below:

Figure A: A 65-year-old diabetic presents with rapidly progressive gait instability. Serum labs show an elevated WBC, CRP, and ESR.

Figure B: A 72-year-old male presents with slowly progressive gait instability over the last 5 years.

Figure C: A 42-year-old male presents with the acute onset of left arm pain and triceps weakness.

Figure D: A 72-year-old active female who plays golf on a regular basis presents with severe neck pain 3 weeks after falling down the stairs.

Figure E: A 37-year-old female presents with vertigo and bilateral upper extremity weakness that has presented intermittently over the last 5 years.

QID: 210200

Figure A



Figure B



Figure C



Figure D



Figure E



L 3 A

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(SBQ13PE.7) A 45-year-old HIV-positive homeless man presents with increasing low back pain for the last three weeks. He now reports difficulty ambulating, fever, and loss of appetite. He denies bowel and bladder symptoms. He denies any symptoms radiating into his buttock or legs. On physical exam, he has in obvious discomfort with standing which worsens in the forward flexion position. He has a normal motor and sensory exam in his lower extremities. Blood cultures are performed which come back negative. His imaging is shown in Figures A and B. What would be the most next appropriate step in treatment?

QID: 4935

Broad spectrum antibiotics



Isoniazid, rifampin, and pyrazinamide therapy



CT guided biopsy with cultures



Technetium bone scan



Anterior corpectomy with a retroperitoneal approach, strut grafting and instrumentation



L 2 B

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(OBQ13.274) A 60-year-old female presents with a 2 week history of low back pain. The pain is described as a dull, persistent ache and radiates down to her buttocks but not past the horizontal gluteal crease. She has a history of Type 2 diabetes mellitus and urinary incontinence. Examination reveals loin tenderness, paravertebral muscle spasm and diminished reflexes but full strength and sensation in the lower extremities. T2-, T1-weighted, and T1 contrast enhanced sagittal MRI images are shown in Figures A through C, respectively. What is the most likely diagnosis and most appropriate treatment plan

QID: 4909

These are Modic Type I changes and treatment will involve NSAIDS, a short period of bed rest and physical therapy



These are Modic Type I changes and treatment will involve a lumbar corset and physical therapy



This is spondylodiscitis and treatment will involve intravenous antibiotics and a thoracolumbosacral orthosis (TLSO).



This is spondylodiscitis and treatment will involve needle biopsy, intravenous antibiotics and a thoracolumbosacral orthosis (TLSO).



This is spondylodiscitis and treatment will involve anterior decompression and stabilization, and intravenous antibiotics.



L 3 C

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(SBQ12SP.20) Amphotericin B is most appropriate for the treatment of which type of spine infection?

QID: 3718

Fungal osteomyelitis



Bacterial osteomyelitis with a gram-positive organism



Bacterial osteomyelitis with a gram-negative organism



Tuberculous osteomyelitis



Viral meningomyelitis



L 1 B

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(OBQ12.32) A 69-year-old male presents to the emergency room with low back pain for 1 week duration. His past medical history is significant for diabetes and coronary artery disease that was treated with stenting 7 years prior. Recently he was hospitalized for a urinary tract infection which was treated with oral antibiotics. On physical exam he is afebrile and has no neurologic deficits in his lower extremity. Laboratory studies show a white blood cell count of 10,300/mm3, an erythrocyte sedimentation rate of 35 mm/h (reference range, 0-25 mm/h), and C-reactive protein of 13 mg/L (reference range, 0-5.0 mg/L). A radiograph and MRI are performed and shown in Figure A and B respectively. Repeat blood cultures x2 are performed and both show methicillin-sensitive Staphylococcus aureus. What is the most appropriate next step in treatment.

QID: 4392

CT guided biopsy



Referral to an orthopaedic pathologist



Organism specific intravenous antibiotics



Posterior lumbar debridement



Anterior lumbar debridement



L 2 B

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(OBQ10.271) A 45-year-old female IV drug user presents to the emergency department with a chief complaint of severe focal low back pain that has progressed over the past 10 days. She now reports the pain is severe enough that it is difficult for her to walk. She reports night sweats, fluctuating fever, and a loss of appetite. Physical exam shows exquisite pain with flexion and extension of the lumbar spine. Routine urinalysis by the ER physician shows evidence of a urinary tract infection. Her blood leukocyte count is 12,600 per mm3, and erythrocyte sedimentation rate is 78 mm/h. A lateral radiograph is shown in Figure A. Which of the following would be the most appropriate next step in treatment?

QID: 3359

Discharge from the ER with a course of oral antibiotics



Admission to the hospital with empirical IV antibiotics



Admission, blood cultures, and MRI of the lumbar spine with and without gadolinium



Nuclear medicine bone scan



Renal ultrasound



L 2 C

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(SBQ06SN.1) A 33-year-old man with a history of IV drug abuse presents with low back pain of increasing intensity. His neurologic examination is intact. Laboratory studies reveal a WBC count of 11,000/mm3 and erythrocyte sedimentation rate of 82 mm/h. Blood cultures are negative x 3. Plain radiographs are shown in Fig A. An MRI T1-weighted images and a post gadolinium fat-suppressed T1-weighted images are shown in Fig B. Initial management should consist of:

QID: 1686

Physical therapy with supportive therapy



IV antibiotics



Open surgical decompression and biopsy



CT-guided closed biopsy



Repeat MRI in 6 weeks



L 3 C

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Evidence (22)
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