Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6052_Библиотеки_им_академика_М_И_Перельмана.pdf
218
20
Spinal Infections
Vertebral Osteomyelitis
I. Incidence/risk factors
A. Approximately 2 to 7% of all osteomyelitis (1 to 2% in children)
B. Lumbar thoracic cervical
C. Males females (2:1)
D. More common after the 5th decade (50% of cases)
E. More common in young intravenous drug abusers, diabetics, and im-
munocompromised (chronic steroids, HIV, malnutrition)
II. Etiology
A. Hematogenous spread is the most common route for vertebral
osteomyelitis.
1. Urinary tract most common source (urinary tract infections, transient
bacteremia from genitourinary procedures)
2. Soft tissue infections
3. Respiratory infections
B. Unidentified source
C. Direct inoculation (penetrating trauma, invasive spinal procedure)
D. Causative bacteria (in order of frequency)
1. Gram-positive aerobic cocci (80%)
a. Staphylococcus aureus (50%)
(1) Methicillin-resistant S. aureus (7%)
b. Streptococcus (10 to 20%)
c. Coagulase-negative staphyloccus (10%)
2. Gram-negative aerobic cocci (15 to 20%)
a. Most common origin is from the urinary tract (Escherichia coli,
Pseudomonas aeruginosa, Proteus)
3. Gastrointestinal tract organisms
a. Salmonella (rare)
(1) More common in patients with sickle cell
◆
Chapter 20 Spinal Infections 219
III. Pathology
A. Inoculation
1. Hematogenous spread to the vertebral metaphysis most likely occurs
via rich arterial anastamosis (nutrient artery) (Fig. 20–1).
a. Batson’s valveless venous plexus is not considered to play a signifi-
cant role in bacterial hematogenous seeding.
b. Vertebral metaphysis is a low-flow environment that may allow for
the direct spread of bacteria into and across the intervertebral disk.
B. Spread to the intervertebral disks
2. Bone/disk destruction (Fig. 20–2)
a. Bacteria produce enzymes that digest disk tissue.
b. Bone resorption by osteoclasts activated by various inflammatory
mediators
C. Soft tissue extension
1. Psoas abscess
2. Paraspinal muscle abscess
3. Epidural abscess
a. May result in neurological compromise secondary to direct com-
pression of the spinal cord and nerve roots
IV. Clinical findings
A. Delay in diagnosis is common.
B. Back or neck pain is the most common presenting complaint (90%).
1. Symptoms are typically present for more than 3 months in 50% of patients.
2. Acute presentation with septicemia and toxemia extremely rare
Figure 20–1 Sagittally sectioned human fetal specimen (26 weeks gestation), injected, cleared,
and transilluminated, showing cartilage canals and absence of vessels in nucleus pulposus. (A) Car-
tilage canal; (B) nucleus pulposus; (C) hyaline cartilage; (D) ossified vertebral body.
220 V Miscellaneous
Figure 20–2 Seventy-six-year-old woman with rheumatoid arthritis and a T12–L1 discitis/L1 os-
teomyelitis. Results of three needle biopsies were negative. (A,B) Anteroposterior and lateral radi-
ographs demonstrated a discitis at T12–L1 with destruction of the L1 vertebral body. (C) T1-
weighted sagittal MRI sequence shows decreased signal throughout and across the T12–L1 disk
space. The end plates are blurred and indistinct. (D) T2-weighted sagittal MRI sequence shows
high signal within the T12–L1 disk and the L1 vertebral body.
C. Localized pain and tenderness with a decreased range of motion are the
most consistent findings.
D. History of fever 100 F (with or without chills) is present in over 50% of
patients.
E. In children, a limp and refusal to walk are characteristically present.
V. Laboratory findings (Table 20–1)
VI. Radiographic imaging studies (Table 20–2)
VII. Treatment
A. Goals
1. Establish a tissue diagnosis and identify the organism.
2. Eradication of the infection
Chapter 20 Spinal Infections 221
3. Provide long-term pain relief.
4. Prevent or relieve any neurological deficits.
5. Restore spinal stability/alignment.
B. Principles
1. Medically optimize the patient
a. Nutritional supplementation
b. Treat laboratory abnormalities
2. Treat extraspinal sources of infection
a. Urinary tract
b. Cardiovascular (infected thrombus)
c. Gastrointestinal
3. Avoid antibiotic therapy prior to identification of the organism if possible.
a. Except in septic patients where broad-spectrum antibiotics are
indicated
Figure 20–2 (Continued) (E) T1-weighted sagittal MRI sequence with gadolinium shows enhancement
of the T12–L1 disk space and L1 vertebral body. There is a slight amount of enhancing tissue in the ante-
rior epidural space without compression of the conus medullaris or cauda equina. (F) T1-weighted axial
MRI sequence with gadolinium shows enhancement of the T12–L1 disk space. (G,H) Anteroposterior
and lateral radiographs taken 6 months after surgery demonstrating incorporation of the bone graft an-
teriorly with solid fixation posteriorly.
222 V Miscellaneous
Table 20–1 Laboratory Morkers in Spinal Infections
Test Findings
ESR Elevated at presentation in more than 80% of cases.
ESR normalizes in
2
/
3
of patients adequately treated.
WBC 10,000/mm
3
in more than 50% of cases.
WBC count has a low sensitivity for diagnosis.
CRP More sensitive and specific than ESR for monitoring postoperative
spine infections.
Blood cultures Most useful in children with vertebral pyogenic osteomyelitis.
Only positive in 35% of patients.
Reliable in detecting the offending organism.
Needle biopsy False-negative examinations are common when patient is on antibiotics.
Open biopsy Indicated if needle biopsy is negative, nondiagnostic, or both despite
high clinical suspicion.
Lower false-negative rate than closed biopsy.
ESR, erythrocy te sedimentation rate; WBC, white blood cell count; CRP, C-reactive protein.
Table 20–2 Diagnostic Imaging in Spinal Infections
Imaging Study Findings
Plain radiographs Findings lag behind clinical presentation (at least 2 weeks
from the onset of infection)
• Disk space narrowing with erosive changes (75%)
• Osteolysis, diffuse osteopenia, focal defect
• 50% trabecular bone destruction before radiographic
evidence is noted
• Osteosclerosis (11%)
• Chronic cases may reveal spontaneous bone fusion (50%)
Nuclear imaging Effective as an initial screening tool
• Earlier detection and localization when compared with
plain films
Combination of gallium (inflammatory) and technetium (bone)
scans provides 90% accuracy in diagnosis
Indium-111-labeled leukocyte (white blood cell) scans are not
sensitive in the spine
• High false-negative rate may be related to leukopenia
Computed tomography Best modality for identifying bone destruction
Magnetic resonance Imaging modality of choice for spine infections
imaging • T1-weighted images—decreased signal around adjacent
end plates and disk space
• T2-weighted images—high signal intensity in bodies
near adjacent endplates and disk space
• Loss of end plate definition
• Involved portions of disks and vertebral bodies enhance
with gadolinium
Allows for visualization of soft tissue involvement (paraspinal,
psoas abscess)
Best imaging modality to differentiate infection versus tumor
Chapter 20 Spinal Infections 223
4. Antibiotic therapy should be specific to the organism identified.
5. Erythrocyte sedimentation rate (ESR) and C-reactive protein levels are
useful to obtain prior to therapy.
a. May be followed as an indication of treatment efficacy.
C. Operative treatment
1. Indications
a. Cases that have failed nonoperative management.
b. Progressive neurological deficit
(1) Due to direct compression from the infection
(2) Due to progressive deformity or instability
c. Abscess or granuloma formation
(1) Antibiotics are ineffective.
d. Intractable pain not responsive to conservative measures
2. Technique
a. Anterior approach is the most useful for vertebral body debridement
(corpectomy).
(1) Laminectomy alone for decompression is contraindicated be-
cause of the potential for spinal destabilization.
b. Autogenous bone graft is the gold standard for reconstruction (iliac
crest, rib, or fibula).
(1) However, autograft-filled titanium cages and cortical strut
allograft have demonstrated good clinical results.
c. Thoracic and lumbar vertebral osteomyelitis may be treated by a
single posterior approach (debridement and fixation) using an
interbody technique.
Epidural Abscess
I. Etiology
A. Associated with vertebral pyogenic osteomyelitis in 28% of cases
B. S. aureus most common causative organism (60%)
C. Regional or location frequencies
1. Thoracic (50%)
a. Neurological deficits more common
2. Lumbar (35%)
3. Cervical (14%)
D. Most cases are in adults (rare in children).
1. Postoperative (16%)
II. Clinical presentation
A. Highly variable, leading to misdiagnosis and delayed treatment in 50%
of patients
B. Localized spine tenderness more common
C. Nuchal rigidity and other meningeal signs possible
D. With or without neurological deficit
◆
224 V Miscellaneous
III. Diagnosis
A. ESR elevated in 98% of cases
B. White blood cell count (WBC)—unreliable
C. Magnetic resonance imaging (MRI) is the imaging modality of choice.
1. Intense focal signal on T2.
2. Epidural metastasis and subdural abscess should be considered in the
differential.
IV. Treatment
A. Epidural abscess requires urgent surgical attention.
B. Epidural abscess in the presence of a worsening neurological deficit is a
surgical emergency.
1. Exceptions
a. May consider nonoperative treatment consisting of antibiotic therapy
with close monitoring if surgery would endanger the patient’s life
Disk Space Infections
I. Epidemiology/etiology
A. May occur as a result of direct inoculation
1. Surgical procedures
a. Discogram
b. Discectomy
c. Intradiscal Electrothermal Therapy
B. Hematogenous spread
1. This is the route most commonly encountered in the pediatric population.
a. Blood supply from the disk is from the surface of the adjacent ver-
tebral bodies.
C. Lumbar spine most commonly involved
II. Clinical findings
A. Typical patient is between 2 and 7 years of age.
1. Patients may not complain of back pain.
2. Limping, refusal to walk, or hip pain may be presenting symptoms.
B. ESR and WBC are elevated.
C. MRI or bone scan are positive early in the disease.
1. Plain radiographs may demonstrate narrowing of the intervertebral
space, sclerosis, or bony erosion.
III. Treatment
A. Surgery is rarely indicated or needed.
B. Immobilization with a brace
C. Antibiotic therapy
D. Biopsy indicated if antibiotics are not effective
◆
Chapter 20 Spinal Infections 225
Tuberculosis of the Spine
I. Epidemiology/etiology
A. Most common granulomatous infection in the world
B. Hematogenous spread is the most common source (pulmonary or gas-
trointestinal infections).
C. Spine is the most common source of skeletal involvement.
1. Most involve the anterior spine.
2. Involvement of adjacent levels from expansion through the disk space
3. Fifty percent of infections are localized and can be categorized (Fig. 20–3).
a. Peridiscal (most common)
(1) Starts in the metaphysis and spreads under the anterior longi-
tudinal ligament
(2) Central (rare)—starts within a single vertebral body
(3) Anterior (rare)—starts under the anterior longitudinal ligament
II. Clinical presentation/diagnosis
A. Pain present with evidence of systemic illness
1. Fevers, malaise, and weight loss
B. Local tenderness, muscle spasm, and limited range of motion
C. Tissue biopsy can by difficult because of the long incubation period for
mycobacterium.
1. Fifty percent false-negative rate
D. Differential diagnosis
1. Neoplasms
2. Sarcoidosis
3. Charcot spine
III. Radiological evaluation
A. MRI is the modality of choice.
1. Unique characteristics of tuberculosis versus pyogenic infections
a. Disk space often spared
b. Involvement of anterior bodies over contiguous segments
c. Paraspinal abscesses and granulomas distinguished with the use of
gadolinium
IV. Surgical treatment (Fig. 20–4)
A. The Hong Kong procedure
1. Anterior approach for anterior pathology
2. Radical debridement and removal of all necrotic tissue
3. Strut graft/fusion using autograft or allograft restoring anterior column
support
4. Posteriorly supplemented instrumentation in more than two levels an-
teriorly
B. Laminectomy alone is contraindicated.
◆
226 V Miscellaneous
Figure 20–3 Radiographic features of the three types of tuberculous spondylitis. (A) Peridiscal in-
volvement is characterized by disk-space narrowing followed by variable bone destruction. The ra-
diograph on the left is early in the disease. The radiograph on the right is after resolution of the dis-
ease with minor deformity. (B) Anterior multilevel disease is distinguished by scalloped erosions of
the anterior aspect of several adjacent vertebrae (T11, T12, L1). (C) Central involvement resembles
a tumor with central body rarefaction and bone destruction followed by collapse (L1 and L2).
Postoperative Infections
I. Early versus late
A. Early infections are typically recognized by systemic complaints.
1. Fevers, chills, local wound erythema, drainage, increased back pain
◆
Chapter 20 Spinal Infections 227
B. Late infections
1. More common, particularly in the presence of instrumentation
a. Difficult clinical diagnosis that should be considered if significant
risk factors are apparent.
II. Superficial versus deep
A. Difficult to differentiate by physical examination
1. In all cases, the irrigation and debridement should include opening the
deep fascial layer to evaluate for the presence of an occult deep wound
infection (Table 20–3).
Figure 20–4 Tuberculosis of the lumbar spine. Fifty-two-year-old man with disseminated tu-
berculosis was treated with 1 year of therapy with three antituberculous drugs. He presented
with progressive low back pain and neurogenic claudication. (A) Anteroposterior and (B) lateral
lumbar spine radiographs show collapse of L2 and L3 with kyphotic deformity. (C) T1-weighted
image sagittal MRI sequence demonstrates decreased signal in the bodies of L1 to L4, kyphotic
deformity, and epidural mass composed of necrotic bone, disk, and purulent debris. (D) T2-
weighted sagittal MRI sequence demonstrates areas of high signal intensity within the L2 and L3
vertebral bodies and in the anterior paraspinal region.