Orthopedics

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Case Reports 

Multilevel Diskitis and Vertebral Osteomyelitis After Diskography

Mark M. Mikhael, MD; Harold G. Bach, MD; Paul M. Huddleston, MD; Timothy P. Maus, MD; Elie F. Berbari, MD

Abstract

Diskitis is a rare but serious complication following diskography. The signs and symptoms may be easily confused or attributed to patients’ preexisting chronic axial degenerative conditions. Unrecognized, it can progress to deep-seated infection with vertebral osteomyelitis. This article presents a case involving a 4-level destructive vertebral osteomyelitis following multilevel diskography despite prophylactic antibiotics and a double-needle technique. A 38-year-old man with radicular symptoms underwent a microdiskectomy at L4-5. Due to only minimal improvement in pain postoperatively, the patient underwent a diagnostic lumbar diskography at L2-3, L3-4, L4-5, and L5-S1 at an outside institution in consideration for repeat surgical treatment. Following this procedure, the patient continued to have debilitating symptoms and presented to our institution, where evaluation revealed elevated inflammatory biomarkers. Magnetic resonance imaging (MRI) suggested diskitis and vertebral osteomyelitis with compression fractures at the 4 levels where the diskography was performed. The patient was successfully treated with parenteral antibiotics targeted at Staphylococcus saccharolyticus, which was isolated in the culture from an open biopsy specimen after an initial percutaneous biopsy was inconclusive. Magnetic resonance imaging is the best radiologic modality for early diagnosis of this complication. This case demonstrates that early changes on MRI should warrant immediate workup and treatment. Treatment involves at least 6 weeks of parenteral antimicrobial therapy.

Provocation diskography is an invasive procedure used to establish a diagnosis of diskogenic pain. This procedure is performed prior to pursuing surgical or percutaneous intradiskal treatment. Destructive vertebral diskitis and osteomyelitis is a rare but serious complication that can result from diskography. It is reported that the overall incidence of diskitis following diskography is <0.25% by patient and <0.14% by disk.1, 2 The risk of diskitis can be further reduced when a stiletted needle or 2-needle technique is used.3, 4

It is believed that diskitis following diskography occurs as a result of direct bacterial inoculation into the intervertebral disk via a contaminated needle.4 The use of prophylactic antimicrobial therapy systemically or via direct injection in the disk has been advocated as a means to reduce the risk of diskitis.2 Vertebral osteomyelitis may result from longitudinal extension of infection from adjacent disks,5 which in turn may lead to local deformity and instability.

Magnetic resonance imaging (MRI) is the best imaging modality to diagnose this complication early. Diskitis may present clinically with increasing pain or systemic complaints of malaise, fevers, or chills. Laboratory testing with elevated C-reactive protein and erythrocyte sedimentation rate may suggest an inflammatory or infective process. Biopsy can confirm the diagnosis of disk space infection.

A PubMed search was done using the terms “osteomyelitis,” “diskography,” and “diskitis” to review the literature. No reported cases of 4-level destructive osteomyelitis following diskography were found. Case reports exist in the literature of single-level diskitis with vertebral osteomyelitis following epidural catheter use.6-11 This article describes progressive 4-level diskitis and osteomyelitis with pathologic compression fractures following multilevel diskography despite the use of prophylactic antibiotics and a double-needle technique. Early changes on MRI should be identified and aggressively pursued. Additionally, a repeat open biopsy should be performed, even after initial image-guided biopsy is negative, if clinical suspicion is high for infection.

A 38-year-old man with no significant comorbidities underwent a left microdiskectomy at the L4-5 level for a disk herniation after failing several months of conservative management for unremitting back pain. Due to the lack of clinical improvement following the procedure, the patient underwent a 4-level diagnostic lumbar diskography at L2-3, L3-4, L4-5, and L5-S1 2 months later (Figure 1). The procedure was performed at an outside facility, which used prophylactic intradiskal antibiotics; a standard prepping, draping, and sterile technique; and a double-needle technique. The patient…

Abstract

Diskitis is a rare but serious complication following diskography. The signs and symptoms may be easily confused or attributed to patients’ preexisting chronic axial degenerative conditions. Unrecognized, it can progress to deep-seated infection with vertebral osteomyelitis. This article presents a case involving a 4-level destructive vertebral osteomyelitis following multilevel diskography despite prophylactic antibiotics and a double-needle technique. A 38-year-old man with radicular symptoms underwent a microdiskectomy at L4-5. Due to only minimal improvement in pain postoperatively, the patient underwent a diagnostic lumbar diskography at L2-3, L3-4, L4-5, and L5-S1 at an outside institution in consideration for repeat surgical treatment. Following this procedure, the patient continued to have debilitating symptoms and presented to our institution, where evaluation revealed elevated inflammatory biomarkers. Magnetic resonance imaging (MRI) suggested diskitis and vertebral osteomyelitis with compression fractures at the 4 levels where the diskography was performed. The patient was successfully treated with parenteral antibiotics targeted at Staphylococcus saccharolyticus, which was isolated in the culture from an open biopsy specimen after an initial percutaneous biopsy was inconclusive. Magnetic resonance imaging is the best radiologic modality for early diagnosis of this complication. This case demonstrates that early changes on MRI should warrant immediate workup and treatment. Treatment involves at least 6 weeks of parenteral antimicrobial therapy.

Provocation diskography is an invasive procedure used to establish a diagnosis of diskogenic pain. This procedure is performed prior to pursuing surgical or percutaneous intradiskal treatment. Destructive vertebral diskitis and osteomyelitis is a rare but serious complication that can result from diskography. It is reported that the overall incidence of diskitis following diskography is <0.25% by patient and <0.14% by disk.1, 2 The risk of diskitis can be further reduced when a stiletted needle or 2-needle technique is used.3, 4

It is believed that diskitis following diskography occurs as a result of direct bacterial inoculation into the intervertebral disk via a contaminated needle.4 The use of prophylactic antimicrobial therapy systemically or via direct injection in the disk has been advocated as a means to reduce the risk of diskitis.2 Vertebral osteomyelitis may result from longitudinal extension of infection from adjacent disks,5 which in turn may lead to local deformity and instability.

Magnetic resonance imaging (MRI) is the best imaging modality to diagnose this complication early. Diskitis may present clinically with increasing pain or systemic complaints of malaise, fevers, or chills. Laboratory testing with elevated C-reactive protein and erythrocyte sedimentation rate may suggest an inflammatory or infective process. Biopsy can confirm the diagnosis of disk space infection.

A PubMed search was done using the terms “osteomyelitis,” “diskography,” and “diskitis” to review the literature. No reported cases of 4-level destructive osteomyelitis following diskography were found. Case reports exist in the literature of single-level diskitis with vertebral osteomyelitis following epidural catheter use.6-11 This article describes progressive 4-level diskitis and osteomyelitis with pathologic compression fractures following multilevel diskography despite the use of prophylactic antibiotics and a double-needle technique. Early changes on MRI should be identified and aggressively pursued. Additionally, a repeat open biopsy should be performed, even after initial image-guided biopsy is negative, if clinical suspicion is high for infection.

Case Report

A 38-year-old man with no significant comorbidities underwent a left microdiskectomy at the L4-5 level for a disk herniation after failing several months of conservative management for unremitting back pain. Due to the lack of clinical improvement following the procedure, the patient underwent a 4-level diagnostic lumbar diskography at L2-3, L3-4, L4-5, and L5-S1 2 months later (Figure 1). The procedure was performed at an outside facility, which used prophylactic intradiskal antibiotics; a standard prepping, draping, and sterile technique; and a double-needle technique. The patient was found to have discordant pain at the lower 4 lumbar levels. Over the next 2 months the patient failed to improve with conservative management. Repeat MRI showed new marrow edema adjacent to the endplates of the L2 through L5 disks (Figure 2A).

Figure 1A: Scout films from the diskography procedure illustrating the 4 levels included in the examination Figure 1B: Scout films from the diskography procedure illustrating the 4 levels included in the examination

Figure 1: AP (A) and lateral (B) scout films from the diskography procedure illustrating the 4 levels included in the examination.

The patient presented to our institution 1 month later, and laboratory studies revealed an elevated C-reactive protein of 2.84 mg/dl (nl<0.8 mg/dl) and elevated erythrocyte sedimentation rate of 25 mm/1h (nl<22mm/1h). Magnetic resonance imaging demonstrated progression of the marrow edema in the L2 through S1 segments with compression of the endplates (Figures 2B and C). A fluoroscopic-guided needle biopsy showed no organisms on Gram stain and failed to reveal any organisms when incubated under aerobic and anaerobic conditions.

Due to the inconclusive results and high clinical suspicion for an infectious process, the patient underwent an open biopsy at the L4-L5 disk level, which revealed acute inflammation on microscopic examination. The anaerobic cultures grew Staphylococcus saccharolyticus. Sensitivity indicated susceptibility to penicillins, and a 6-week course of parenteral ceftriaxone was initiated. The patient showed immediate clinical improvement. Three months after completion of antimicrobial therapy, laboratory data and MRI continued to suggest resolution of the lumbar spine infection (Figure 2D).

Figure 2A: T1-weighted sagittal MRI with new marrow edema adjacent to the endplates of the L2 through L5 disks Figure 2B: T1- and T2-weighted sequences 1 month later reveal progression of the marrow edema in the L2 through S1 segments with compression of the endplates Figure 2C: The T2-weighted sequences reveal significant signal changes within the disks Figure 2D: T1-weighted sagittal MRI after completion of antibiotic course showing resolution of marrow edema

Figure 2: T1-weighted sagittal MRI with new marrow edema adjacent to the endplates of the L2 through L5 disks (arrows; A). T1- and T2-weighted sequences 1 month later reveal progression of the marrow edema in the L2 through S1 segments with compression of the endplates (double arrows; B). The T2-weighted sequences reveal significant signal changes within the disks (dashed arrows), as well as intradiskal, marrow, and paraspinal enhancement on post-gadolinium images (C). T1-weighted sagittal MRI after completion of antibiotic course showing resolution of marrow edema (D).

Discussion

To date there are no randomized clinical trials evaluating the efficacy of antimicrobial prophylaxis for diskography. Osti et al4 reported a prospective study of 127 patients undergoing lumbar diskography. With the addition of cefazolin to the injected contrast, none of the patients developed diskitis after an observation period of 3 months.2, 4,12 In addition, it has been reported that the risk of diskitis can be reduced when a stiletted needle or double-needle technique is used.3, 4 When diskitis was first described, it was thought to be a “chemical” diskitis.13 Fraser et al3,14 demonstrated conclusively that this diskitis was due to bacterial infection. The use of a double-needle technique and prophylactic antibiotics has virtually eliminated this complication.13 However, in a recent literature review study involving 200 patients and 435 diskograms, Willems et al12 reported that there is not enough support from the literature to justify the routine use of prophylactic antibiotics when a double-needle technique is used. The present case illustrates that despite these precautions, diskitis and osteomyelitis may occur.

A reported case of spondylodiskitis caused by S. saccharolyticus suggested that the pathogenic potential of this agent may be underestimated due to its delayed anaerobic growth.15, 16 An undiagnosed case of diskitis caused by this pathogen may progress to a serious and destructive vertebral osteomyelitis. Osteomyelitis may take several weeks to appear on radiographs. Computed tomography (CT) scans will identify bone destruction with higher sensitivity than plain films, but cannot delineate the extent of disk or marrow involvement, nor all soft tissue changes. Technetium bone scan performed in combination with gallium scanning is similar in sensitivity to MRI, but fails to give the anatomic information regarding epidural involvement, central canal compromise, or paraspinal abscess necessary to make surgical decisions.

The best noninvasive test for early diagnosis is MRI. Magnetic resonance imaging provides high sensitivity and specificity for infection, as well as critical morphologic information. It has recently been demonstrated that diskography in the absence of infection does not alter the MRI appearance of the disk or adjacent marrow.17,18 Any new findings should be viewed with suspicion. Our patient had significant T1 changes evident on his MRI 2 months following the diskography procedure (Figure 2A). However, these findings can be missed if one doesn’t contemplate the possibility of mono- or multilevel diskitis as potential complications. With progression of the infection, the patient developed more extensive involvement; he had sustained pathologic compression fractures of his endplates at all 4 levels. The T2 sequences were noted to have significant signal changes within the disks, as well as intradiskal, marrow, and paraspinal enhancement on post-gadolinium images.

This case highlights the importance of early diagnosis and treatment. It is also imperative to obtain anaerobic cultures when dealing with infective pathology of the spine. At our institution, we routinely send specimens for culture under aerobic and anaerobic conditions when infection is suspected.

Culture results from a disk biopsy need to be interpreted within the context of the clinical information. Our patient—with clinical and radiologic findings suggestive of diskitis but with a negative image-guided biopsy—had positive cultures after undergoing an open biopsy 2 weeks later.19 Thus, if clinical suspicion is high, a repeat aspirate or open biopsy after cessation of antibiotic therapy can help determine the causative organism.

Guyer et al20 studied the course of post-diskography diskitis in a series of 9 patients. The most consistent sign was the marked exacerbation of pain. This was followed by an elevated sedimentation rate at an average of 20 days, followed by a positive bone scan at an average of 33 days. Of note, 7 patients initially had negative bone scans at an average of 18 days. Magnetic resonance imaging was performed in 6 patients; 2 of these patients were scanned twice. Three scans were negative and 5 were positive (2 patients initially had negative scans that later became positive). In summary, 1 of the 6 patients was noted to have negative MRI; however, 5 of the 6 patients were noted to have early findings on MRI.20

Bone infection requires a 6-week course of systemic antimicrobial therapy.21 Adequacy of the antimicrobial treatment can be assessed with laboratory data, including C-reactive protein and erythrocyte sedimentation rate.22 During this period, particular attention must be paid to the patient’s nutritional status while attempting to optimize host conditions, such as better diabetes control and withdrawal of immunosuppressives, if feasible.22

If a patient does not improve on antibiotic therapy, surgical intervention is indicated. Even with antibiotics, the sequelae of vertebral osteomyelitis may include paralysis and death, especially in the immunocompromised patient.23 Surgery is indicated for a clinically significant abscess, neurologic compromise, severe deformity, or failure of conservative antibiotic treatment with continued infection.23 The mainstay of surgical treatment is adequate debridement and, when necessary, spinal stabilization.24

Conclusion

Diskitis and destructive vertebral osteomyelitis are serious complications that can occur following diskography. Several authors recommend the use of systemic or local antimicrobial prophylaxis prior to diskography.2,4 In addition, it has been reported that the risk of infection can be further reduced when a stiletted needle or double-needle technique is used.3,4 Despite prophylactic antibiotics with a double-needle technique, this complication may still occur. Magnetic resonance imaging is the best imaging modality to diagnose this complication early. Diskography in the absence of infection does not alter the MRI appearance of the disk or adjacent marrow.17,18 Early changes on MRI warrant immediate workup. If image-guided biopsy is inconclusive, an open biopsy should be undertaken after cessation of antibiotic therapy. Treatment involves at least 6 weeks of intravenous antibiotic therapy.

References

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  3. Fraser RD, Osti OL, Vernon-Roberts B. Discitis after discography. J Bone Joint Surg Br. 1987; 69(1):26-35.
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Authors

Drs Mikhael, Bach, and Huddleston are from the Department of Orthopedic Surgery, Dr Maus is from the Department of Radiology, and Dr Berbari is from the Department of Internal Medicine, Division of Infectious Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota.

Drs Mikhael, Bach, Huddleston, Maus, and Berbari have no relevant financial relationships to disclose.

Correspondence should be addressed to: Paul M. Huddleston, MD, Mayo Clinic, 200 First St SW, Rochester, MN 55905.

10.3928/01477447-20090101-16

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