Antibiotics, Debridement, or Fusion?
A 36-year-old male had acute onset of severe radicular pain in an S1 distribution.
The patient had 2 weeks of non-operative care, but then he had an MIS discectomy done at another institution due to the severity of the symptoms. He had a total relief of symptoms, and was discharged the same day.
He returned 2 weeks after surgery because he had developed increasing back pain and recurrent left leg radicular pain.
Five weeks after surgery, the patient was experiencing “horrible” pain and was placed on OxyContin—40 mg, 2 times/day.
At that point, the patient asked his surgeon for another MRI, and the surgeon told him that MIS surgery “never” gets infected.
The patient’s family doctor repeated the MRI, which showed the presence of fluid in the disc space and changes in the endplate that point to discitis.
Figure 1: T1-weighted MRI showing discitis
Figure 2: T2-weighted MRI showing discitis
Possible Treatments at this Juncture
At this time, which of these would you choose?
- CT Biopsy, culture and antibiotics
- Repeat MIS surgery, I & D (irrigation and debridement), antiobiotics
- Open surgery, I & D, antiobiotics
- Open or MIS surgery, I & D and fusion
Selected Treatment and Result
A CT biopsy was performed. The patient cultured staph aureus.
At this point, the patient was put on 4 weeks of antibiotics, and after that time, his pain persisted. His VAS was 8/10, ESR 62, and CRP 7.
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L5-S1 anterior debridement and interbody fusion was performed. Four days later, posterior instrumentation and fusion was done.
Figure 3: Post-operative AP x-ray
Figure 4: Post-operative lateral x-ray
Figure 5: Post-operative axial CT of L5-S1 showing instrumentation
Figure 6: Post-operative lateral CT
Following surgery, the patient was treated with an additional 6 weeks of IV antibiotics. Radiographic imaging demonstrated gradual incorporation of his anterior inter-body graft. The patient had substantial improvement in his lower back pain, but persists with enough discomfort that he routinely takes NSAIDs. He is now 2 years following his second surgical procedure and no additional follow up is scheduled.
Post-operative infections in spine surgery are an important cause of revision surgery and increased cost of care. Surgical site infections in lumbar decompressive surgeries have been reported with significant variability, and rates may be up to 4%. Awareness of this potential complication and a high index of suspicion in the post-operative patient may optimize the timing of treatment.
This case is a 36-year-old male who had an excellent improvement in pain after a discectomy performed through a minimally invasive approach. Rates of complications including infection are similar in open and minimally invasive surgery. The patient had a significant deterioration of his pain and function 2 weeks after his surgery. At that time, careful questioning regarding fevers, chills, and wound drainage may be useful to identify an infection. Pain that is constant, including at rest, and accompanied by fever, chills, or wound drainage would be suggestive of a post-operative infection.
At 5 weeks after surgery, the patient underwent evaluation with MRI, which revealed evidence of fluid in the disc space and endplate changes consistent with infection. In the absence of epidural abscess, instability, or nerve compression, medical management is appropriate. CT-guided aspiration demonstrated staphylococcus aureus infection, and the patient had persistence of pain and elevated ESR and CRP after 4 weeks of intravenous antibiotics.
In the setting of persistence of pain and failure of response to antibiotic care, operative debridement is the most reliable method for eradication of infection. The choice of a combined anterior and posterior approach is well-guided and optimized debridement of infected tissue while limiting the possibility of progressive deformity. There is good evidence that primary instrumentation with allograft or metal implants will result in a low risk of recurrent infection. Osteobiologics including rhBMP may also limit the rate of recurrent infection and improve healing.
Surgical site infections are important, and early recognition and treatment may optimize outcomes of care. In this case, it is not clear that antibiotics would have been more effective if started earlier, and antibiotics are a reasonable first-line approach in a non-instrumented case without epidural abscess or instability. Primary reconstruction with implants is a reliable surgical option for the treatment of spine infections.