VERTEBRAL OSTEOMYELITIS.pptx

Pyogenic vertebral osteomyelitis

1. VERTEBRAL OSTEOMYELITIS

2. PYOGENIC SPINAL INFECTIONS - INTODUCTION Successful management of spine infections requires a high level of diagnostic acuity to avoid delays in diagnosis, use of appropriate antibiotic therapy as directed by biopsy results, and institution of appropriate surgical intervention when indicated. numerous ways to classify spine infections. By the the histologic response of the host to the specific organism- Most bacteria cause a pyogenic response, whereas Mycobacterium, fungi, Brucella , and syphilis induce granulomatous reactions

3. Based on primary anatomic location—vertebral osteomyelitis, discitis , or epidural abscess By cause; the main routes of infection are hematogenous , direct inoculation (postoperative and traumatic), and spread from a contiguous source Each of these classifications has implications with regard to evaluation, treatment, and prognosis.

4. Vertebral Osteomyelitis Represents 2% to 7% of all cases of osteomyelitis predilection for the elderly- Approximately one-half of the patients with spine infections are more than 50 years old and two-thirds are male ref – Rothman- Simeone

5. ETIOLOGY Any condition that causes a bacteremia may lead to hematogenous vertebral osteomyelitis. Approximately 50% of cases are thought to seed the vertebral column through arterial or venous conduits at the intervertebral disc or endplates. Another 40% are from direct inoculation, such as after a spine procedure. The remaining cases are from local extension from adjacent areas of infection.

6. Most frequent sources are urinary tract infections and the transient bacteremia caused by genitourinary procedures Soft tissue infections Respiratory tract infections Direct inoculation of bacteria into the spine by penetrating wounds, spine surgery, chemonucleolysis , or discography Immunocompromised hosts – HIV , DM , steroids , IV drug abusers M/C organism – staphylococcus aureus

7. PATHOGENESIS Wiley and Trueta , demonstrated the rich arterial anastomosis within the vertebral body, with end arterioles in the metaphyseal region. Spinal arteries enter the canal through the intervertebral foramen at the level of the disc. Branches ascend and descend, supplying the vertebral bodies above and below.

8. Through their injection studies, they demonstrated how bacteria could easily spread hematogenously to the metaphyseal region of adjacent vertebrae. The infection may also start in the metaphyseal region of one vertebra and either spread across the avascular disc by lysosomal destruction of the nucleus pulposus or through vessels anastomosing on the periphery of the anulus fibrosus.

9. Once microorganisms lodge in the low-flow vascular arcades in the metaphysis, infection spreads. The disc is destroyed by bacterial enzymes in a manner similar to the destruction of cartilage in septic arthritis. This is in contrast to tuberculous infections in which the endplates and bone are destroyed, but the disc is frequently better preserved.

10. Abscesses may drain into the soft tissues surrounding the spine or into the spinal canal itself. In the cervical spine, a retropharyngeal abscess may invade the mediastinum. In the thoracic spine, an abscess may be paraspinous or retromediastinal . Infection in the lumbar spine may cause a psoas abscess or, less commonly, an abscess pointing through the Petit triangle. Occasionally, an abscess may create a tract through the greater sciatic foramen and appear in the buttock ,in the perirectal region, or even in the popliteal fossa.

11. An abscess that enters the spinal canal is considered to be an epidural abscess Infection may cross the dura , causing a subdural or intradural abscess or meningitis. Pathogenesis of neural compromise may be related to direct compression by epidural pus, granulation tissue, or bone and disc from the development of spinal deformity and instability. The cord or nerve roots may suffer ischemic damage from septic thrombosis or may be damaged by inflammatory infiltration of the dura

12. Osteomyelitis in OVCF Osteomyelitis may develop as a complication of the fracture because the fracture creates a favorable environment for the hematogenous infection. Alternatively, the osteomyelitis may develop within the central portion of an osteoporotic vertebral body, perhaps because the bone is more hyperemic or because of vascular stasis. Infection may then lead to a pathologic fracture of the vertebra.

13. This patient with a T7–T8 disc space infection with associated vertebral osteomyelitis developed progressive paraplegia and died as a result of overwhelming sepsis associated with antibiotic-induced neutropenia. (A) Lateral radiograph showing marked narrowing and sclerosis at the T7–T8 interspace (arrowhead). (B) Diagram showing pathology shows the collapse centered at the T7–T8 interspace and associated paraspinal abscess. (C) Two months later, infection spread down to the T9–T10 interspace, with marked narrowing at that level. Gross destruction of the disc can be seen on this gross pathology specimen at the T7–T8, T8–T9, levels

14. CLINICAL PRESENTATION ACUTE Pain in the back or neck Fever severe muscle spasm Limitation of motion of the spine

15. Positive straight-leg raise test Reluctance to bear weight Hip flexion contracture due to psoas irritation. Hamstring tightness Loss of lumbar lordosis . Torticollis and fever may be the only presenting signs with cervical osteomyelitis Neurological deficits secondary to nerve root or spinal cord involvement

16. Sub acute and chronic More insidious, and these patients have a vague history. Pain may be the only symptom, especially with an occult infection by a low virulent organism. May have atypical symptoms such as chest pain, abdominal pain, hip pain, radicular symptoms, or meningeal irritation. These unusual and often vague complaints have led to unnecessary exploratory laparotomies before the diagnosis has been made.A significant delay in diagnosis is common with chronic infections.

17. Deformity in vertebral osteomyelitis With the advent of antibiotics, significant spine deformity is not as common as it was in the past, but kyphosis still may occur. Bacterial infection in the vertebral body can lead to increased intraosseous pressures and impede blood flow to the vertebrae and discs, leading to ischemic necrosis and subsequent deformity. Additionally, production of hyaluronidase by certain bacteria can invade the annulus fibrosus and cause proteolytic breakdown and subsequent biomechanical instability and deformity

18. Diagnostic modalities 1) laboratory investigations CBC , ESR , CRP Gram stain Culture

19. IMAGING ( PLAIN XRAY , CT , MRI ) Narrowing of the disc space Endplate destruction Osteolysis Vertebral collapse Gas in the disc space- May represent infection with a gas-forming organism

20. This patient presented with a significant paraparesis and associated sepsis. (A) This lateral radiograph demonstrates marked diminution in the height of the L2 vertebral body. It is surprising that the disc heights at L1–L2 and L2–L3 appear to be relatively normal. (B) Tomograms of the lumbar spine reveal gas shadows (arrows) within the disc spaces at L1–L2 and L2–L3. At the time of surgical debridement, Escherichia coli was cultured.

21. 50 y , died with thoracic vertebral osteomyelitis secondary to overwhelming meningitis associated with spine infection following a urologic procedure with associated post op sepsis

22. This patient presented with an idiopathic disc space infection at L5–S1 with an associated vertebral osteomyelitis. His main complaint was low back pain. (A) This lateral radiograph demonstrates marked narrowing of the disc space at L5–S1; however, nothing is seen on this radiograph that would clearly demonstrate this to be a spine infection. (B) This lateral tomogram better demonstrates the destruction of the endplates at L5–S1 and the rarefaction of the adjacent bone. The only diagnosis consistent with these findings is a disc space infection with associated vertebral osteomyelitis .

23. CT Cystic changes in the bone as well as soft tissue masses Gas in the soft tissues or within the bone and disc and, later, lytic destruction of the body. The prevertebral soft tissue involvement seen on CT usually completely surrounds the spine anteriorly, and the destruction of the vertebra is generally an osteolytic process around the disc space This is in contrast to neoplasms –shows no or only partial paravertebral soft tissue swelling and by changes that may be osteoblastic and more likely to involve posterior elements than in infection

24. Widening of the retropharyngeal space in the cervical spine Enlargement of the paravertebral shadow in the thoracic spine Changes in the psoas shadow in the lumbar spine may indicate either abscess or granulation tissue surrounding the infection

25. This infant developed a vertebral osteomyelitis and life-threatening sepsis. Unlike the relatively benign disc space infection of childhood, this infection of infancy follows a much more destructive course. (A) At the time that the infant became septic, the T6 vertebral body could be clearly visualized (arrow). (B) Two months later, despite aggressive antibiotic treatment, there is gross destruction of the T6 vertebral body (arrow). (C) This lateral radiograph taken 2.5 years after the spine infection reveals that the patient has a kyphotic deformity from T5 to T7. This deformity behaves much like an anterior failure of formation of the T6 vertebral body . (From Eismont FJ, Bohlman HH, Soni PL, et al. Vertebral osteomyelitis in infants. J Bone Joint Surg Br. 1982;64[1]:32–35.

26. Computed tomography scan with (A) sagittal and (B) axial images of the lumbar spine of an active intravenous drug abuser. Severe destruction of L5 can be seen. The patient presented with severe back pain, bilateral dorsiflexor weakness, and fever. The L5 vertebral body and the inferior portion of L4 have been destroyed by infection. Cultures revealed Staphylococcus aureus . (From Eismont FJ, Bohlman HH, Soni PL, et al. Vertebral osteomyelitis in infants. J Bone Joint Surg Br. 1982;64[1]:32–35.

27. CT – TB vs Pyogenic infections TB - the soft tissue components tend to be more prominent vertebral fragmentation and paraspinal calcifications – unique feature of TB The destruction tends to extend into the pedicle, which is uncommon in pyogenic infections

28. MRI The imaging modality of choice for the evaluation of spine infections is MRI Capable of differentiating degenerative and neoplastic disease from vertebral osteomyelitis

29. On T1-weighted sequences, there is a confluent decreased signal intensity of the vertebral bodies and adjacent disc, making the margin between the two structures indistinct. On T2-weighted sequences, the signal intensity of the vertebral bodies and the involved disc is higher than normal, and there is generally an absence of the intranuclear cleft normally seen within the adult disc

30. T1-weighted contrast-enhanced magnetic resonance axial image through lumbar spine. Increased signal intensity can be seen diffusely in the psoas muscle bilaterally with low signal intensity abscess pockets (arrows)

31. (A) Preoperative imaging studies show L3–L4 disc height loss and irregular endplate sclerosis on lateral radiographs. (B) Contrast-enhanced magnetic resonance image shows involvement of the L3–L4 disc space along with increased signal of the L3 and L4 vertebral bodies. (C) Axial image shows enhancement of the anterior soft tissues (arrowheads).

32. MRI – TB vs Pyogenic infection Pyogenic vertebral osteomyelitis differs from TB spondylitis by severe disc space destruction with relative preservation of the vertebral body TB spondylitis “skips the disc space”

33. Nuclear medicine studies Gallium and technetium bone scans- prefered Indium-111-labeled leukocyte imaging Single-photon emission computed tomography (SPECT)

34. BIOPSY A definite diagnosis is possible by closed-needle biopsy in most of the cases Often false negative in patients who are being treated with antibiotics at the time of the biopsy. If a biopsy is nondiagnostic , it would be reasonable to observe the patient off the antibiotic regimen and repeat the biopsy. If the second closed biopsy is also nondiagnostic , an open biopsy should be considered

35. Biopsy is mandatory for any case of spine infection before institution of antibiotic therapy Only exception are cases with positive blood cultures in association with strong clinical evidence of spine infection

36. DIFFERENTIAL DIAGNOSIS TUBERCULOSIS PYOGENIC COMMONLY INVOLVED REGION Thoracolumbar Lumbar LEVELS Frequently variable Usually paradiscal DISC PRESERVATION Variable Involved early SUBLIGAMENTOUS SPREAD Frequently extensive Limited SKIP LESIONS Frequent Rare PARASPINAL SOFT TISSUE Well defined , large Less well defined , small ENHANCEMENT OF ABSESS WALL Thin , smooth Thick ,irregular ,nodular CALCIFICATION ON CT May be present absent

37. Typhoid spine – weeks to months following typhoid, excruciating pain , spasm+ Radiological picture resemble that of TB or pyogenic spondylitis Confirmation can be obtained by agglutination tests or biopsy

38. Brucella spondylitis - undulant fever+, agglutination test+ , isolation of causative organism ,biopsy More in communities consuming unboiled or unpasteurised milk

39. Mycotic spondylitis -m/c- actinomyces/Blastomyces group In blastomycosis paravertebral abscess formation is a common feature. In actinomycosis sclerosis and destruction of bone proceed hand in hand Vertebral bodies may show irregular saw tooth appearance by periosteal new bone formation Often multiple discharging sinuses present Diagnosis by demonstration of mycotic organisms from the discharging sinus, pus or from the diseased bone

40. Syphilitic infection of spine – Radiological picture shows a gross disorganization and destruction of involved vertebra along with proliferative new bone formation Diagnosis confirmed by serological tests , tissue biopsy

41. Tumours: Hemangioma -m/c benign – vertebral column – D12-L4- asymptomatic incidental finding Coarsening of vertebral trabeculation more prominent in vertical than in horizontal -corduroy appearance

42. Multiple myeloma- Involvement of multiple bones, high ESR, anemia, reversal of albumin globulin ratio and myeloma cells detected on bone marrow study are characteristics + Bence -Jones protein is present in the urine in 60 percent of such cases. Diagnosis may require confirmation by the presence of myeloma cells in the bone biopsy

43. Lymphoma and Leukemia – both of them may present with vague back pain Lymphoma may show deposits in the vertebrae as diffuse sclerosis of bone and destruction of trabecular pattern Leukemias may be associated with collapse of several vertebral bodies and generalised osteoporosis diagnosis -Enlargement of spleen, liver and lymph nodes with characteristic blood changes

44. Secondary neoplastic deposit - Involvement of other bones and destruction of pedicles suggest a metastatic lesion. infective lesion- collapse of the diseased vertebrae and the intervening disc- diminished in size. secondary deposit nearly always involves a vertebral body, which collapses whereas the discs on either side remain unaffected for a long time

45. MANAGEMENT -Goals Establish tissue and bacteriologic diagnoses prevent or reverse neurologic deficits Relieve pain Establish spinal stability Correct symptomatic spinal deformity Eradicate the infection Prevent relapses

46. Treatment should be withheld until an organism is identified in case a second biopsy is necessary. However, patients who are systemically toxic should be treated with maximal doses of broad-spectrum antibiotics as soon as the biopsy has been completed. Most patients with vertebral osteomyelitis are not septic and will not be harmed by a delay in treatment for several days. Conversely, if the biopsy is nondiagnostic and antibiotic therapy has been started, a second biopsy may not yield the organism.

47. Patients with clinical evidence of vertebral osteomyelitis but negative cultures from open biopsy should be treated with a full course of broad-spectrum antibiotics. When possible, the choice of antibiotics should be based on the culture and sensitivity test results so that more specific and less toxic agents can be used

48. At present, it is recommended that parenteral antibiotic therapy be used in maximal dosage for 6 weeks and followed with an oral course of antibiotics until resolution of the disease. Parenteral therapy for less than 4 weeks results in a higher rate of failure ESR and CRP – Guide for the response to therapy Patients should be immobilized for pain control and prevention of deformity or neurologic deterioration.

49. SURGICAL TREATMENT -Indications To obtain a bacteriologic diagnosis when closed biopsy is negative When a clinically significant abscess is present (spiking temperatures and septic course) In cases refractory to prolonged non-operative treatment, in which the ESR and/or CRP remain high or pain persists In cases with spinal cord compression causing a neurologic deficit In cases with significant deformity or with significant vertebral body destruction, especially in the cervical spine . Upper cervical osteomyelitis is rare but generally requires fusion because of the associated instability

50. In most cases spine should be approached anteriorly because this allows direct access to the infected tissues and adequate debridement For lesions in thoracic or thoracolumbar spine, transthoracic approach has the advantage of better exposure, allowing more extensive debridement and better decompression and more effective bone grafting After debridement, anterior strut grafting can be performed Graft should extend from healthy bone above to healthy bone below

51. Autologous bone grafting can be done Iliac crest, ribs,fibular grafts In cases of significant kyphotic deformity, anterior reconstruction with autologous bone grafts after debridement followed by posterior stabilization and fusion Addition of posterior instrumentation provides even better deformity correction and faster rate of fusion

52. References Rothman- Simeone and Herkowitz’s The Spine – 7 th ed Campbell’s textbook of orthopaedics Tuberculosis of the skeletal system – SM Tuli

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