Objective.
Medically acquired infections of the spine are relatively rare, with an annual incidence of 1:100,000 to 250,000 and a progressive increase. The average hospital stay is 30 to 57 days, and the mortality rate is 2 to 17%. This article focuses on the conservative and surgical treatment of medical-derived infections.
Methods.
The diagnosis and treatment of intervertebral discitis was made by reviewing the literature and combining it with our own experience. The pathogenic diagnosis relies on blood cultures, CT-guided puncture, and intraoperative specimen biopsy. Basic treatment principles and surgical indications are discussed.
Results.
Early and stable surgery can will reduce mortality (down to 2%). The combination of surgery and antibiotics can essentially eliminate recurrence (literature recurrence rates of 0-7%). Surgical treatment can improve quality of life.
Conclusion.
Conservative and surgical treatment is increasingly successful through close clinical and radiological observation of patients with intervertebral discitis. Stability surgery must be performed on the diseased segment if there is a clear indication for surgery, which can control the disease and promote early movement of the patient.
Intervertebral discitis is a rare disease that is prone to misdiagnosis and mismanagement because of the non-specific nature of the initial signs and symptoms. The time from initial attack to diagnosis has been reported in the literature to be as long as 2 to 6 months.
Spondylodiscitis is a primary infection of the intervertebral disc caused by a pathogen and an immediate onset of osteomyelitis under the adjacent endplate, usually occurring progressively in the adjacent segment. The annual incidence is 1:100,000 to 250,000. It is the leading cause of hematogenous osteomyelitis over 50 years of age, accounting for 3-5% of all osteomyelitis.
This article discusses the conservative and surgical treatment of medically induced discitis and the prognosis.
General treatment
Principles of treatment: removal of infected foci; maintenance and restoration of the structure and stability of the spine; restoration of neurological function; and pain management.
Basic measures for successful treatment of full recovery from discitis: braking or immobilization of the affected spinal segment; antibiotics; debridement and decompression of the spinal canal as necessary depending on the severity of the disease.
Standard treatment guidelines are lacking because of the diversity of patient populations and treatment modalities. There are no randomized controlled studies. The evidence level for recommended treatment modalities does not exceed grade C.
Targeted antibiotic therapy requires microbiologic diagnosis and intravenous administration of antibiotics based on the pathogens found and drug sensitivity testing. Microbiological examination of the incision and at least three blood cultures are required before discontinuing antipyretic drugs and antibiotics. If a patient requires emergency management because of sepsis or an outbreak of disease, broad-spectrum antibiotics can be used empirically, targeting the most common pathogens of discitis, such as Staphylococcus aureus and Escherichia coli, and blood cultures should be done first. The steps we recommend are: blood culture, CT-guided puncture biopsy, and intraoperative intra-incisional specimen collection.
There is no clear recommendation in the literature regarding the duration of intravenous antibiotic administration. A minimum of 2 to 4 weeks is generally considered. Some observational studies suggest that less than 4 weeks tend to lead to treatment failure. There are some case reports of earlier change from intravenous to oral administration, provided that the patient is generally stable and blood inflammatory markers return to normal or improve significantly. If the intestinal bioavailability of the active ingredient of the drug is high, e.g., fluoroquinolones, clindamycin, linezolid. Linezolid is mainly used for methicillin-resistant Staphylococcus aureus (MRSA) infections, and the drug has hematopoietic side effects.
The literature is similarly lacking in no uniform recommendation for the total duration of antibiotic therapy. For nonspecific discitis, antibiotic use for 6 weeks to 3 months has been recommended. Overall, the duration of use varies from person to person. Exceptional patients (immunosuppressed, diabetic, substance abuse) take longer. Our practice is to discontinue medication after 6 consecutive weeks of normal inflammatory markers.
If the history, clinical and imaging suggest tuberculous discitis, then appropriate treatment should be started immediately. These cases are usually nonfluctuating and therefore can be treated without a rush to find a microbial pathogen. Based on empirical and retrospective data, antituberculous therapy should be continued for 18 to 24 months to prevent recurrence and to provide complete cure. Atypical mycobacteria are often drug-resistant, making treatment very tricky. There is no definitive treatment protocol for atypical mycobacteria. The 1997 guidelines of the American Thoracic Society recommend a combination of isoniazid, rifampin, and ethambutol with or without streptomycin or clarithromycin for the treatment of pulmonary infections.
If a fungal infection is confirmed, antifungal therapy should be administered. Fungal-induced discitis and tuberculous discitis appear similar on MRI. Overall, it is difficult to differentiate between fungal discitis and antifungal therapy is confusing. Therefore, van Ooij et al. advocate early surgical treatment of these diseases.
Indications for conservative treatment: no clear indication for surgery; mild clinical symptoms; minimal bone destruction; high surgical risk. Conservative treatment is usually the preferred option in elderly patients or in patients with poor general condition.
Braking, which is very important, is not easy to do. Adequate braking of the infected segment can reduce the duration of bed rest. For the cervical spine, a cervical brace or hallux rig can be used. For the mid-thoracic spine, an oblique brace allows partial transfer of stress from the involved segment to the lesser articular processes, reducing the pressure on the vertebral body. Even in the thoracolumbar segment or lumbar spine, if the damage is not very severe, support brace braking can be considered. Damage to the lower lumbar or lumbosacral segments, as well as more severe damage to the anterior column, requires a minimum of 6 weeks of bed rest.
Disadvantages of conservative treatment: bed rest complications: decubitus ulcers, deep vein thrombosis, pulmonary embolism, pneumonia. Pseudarthrosis and spinal instability, leading to kyphosis and chronic pain, occurring in 16 to 50% of cases. Conservative treatment should be discontinued in the following cases: 4-6 weeks without bone fusion, progressive destruction, no improvement in clinical symptoms…
During conservative treatment, if a paravertebral abscess occurs, then CT-guided puncture and drainage can be done again to drain the pus.
Surgery
Indications for emergency surgery: 1. neurological impairment;
2.Sepsis.
3. Significant bone destruction leading to instability;
4, imminent or existing deformity;
5. Occupying lesions (abscesses) in the spine;
6, pathogenesis unclear and/or suspected malignant disease;
7.No response to conservative treatment;
8, Uncontrollable pain;
9.Patient compliance is poor
Compared with conservative treatment, surgery can control inflammation safely and quickly. Patients can start activities earlier… The fusion rate is increased to 90~100%. For multi-segmental involvement and long-segmental fusion, pseudarthrosis formation and displacement of implants are likely to occur, resulting in retroflexion deformity. Therefore, internal fixation of the adjacent segment is required.
Decompression of the vertebral plate alone can destabilize the posterior structures and lead to potential nerve damage. Of course, there may also be a risk of pathogen attachment and persistent infection if internal fixation is present within the infected lesion. Internal fixation of the spine can also be successful if debridement is very thorough and local antibiotics are given at the same time. The debridement should reach cancellous bone with a rich blood supply. The use of titanium for internal fixation can reduce the recurrence rate.
The surgical strategy remains controversial. One-stage or two-stage surgery? With neurological symptoms: emergency decompression + internal fixation. Without neurological symptoms: If the patient is not in good health, the surgery can be performed in 2 stages, 1 to 2 weeks apart.
The mode of internal fixation is equally controversial. Posterior alone / Anterior alone / Combined posterior + anterior / Combined anterior + posterior.
The following table shows the authors’ treatment strategy. Factors to be considered: degree of segmental disruption, application of debridement, posterior convexity deformity, and extent of vertebral body accumulation. Severe multi-stage disruption may require multiple surgical debridement and fixation.
There is some mortality associated with discitis due to the high rate of early misdiagnosis and mistreatment and because it primarily affects older patients. The average length of hospital stay is 30 to 49 days. The mortality rate during hospitalization ranges from 2 to 17%.
Recovery of neurological damage:30% have muscle strength loss; 90% have sensory loss and poor quality of life…. …75% of acute paralysis can be recovered. ….. Overall probability of recurrence of discitis 0-7%.