To analyze the clinical courses and outcomes after anterior lumbar interbody fusion (ALIF) for the treatment of postoperative spondylodiscitis.
A total of 13 consecutive patients with postoperative spondylodiscitis treated with ALIF at our institute from January, 1994 to August, 2013 were included (92.3% male, mean age 54.5 years old). The outcome data including inflammatory markers (leukocyte count, C-reactive protein, erythrocyte sedimentation rate), the Oswestry Disability Index (ODI), the modified Visual Analogue Scale (VAS), and bony fusion rate using spine X-ray were obtained before and 6 months after ALIF.
All of the cases were effectively treated with combination of systemic antibiotics and ALIF with normalization of the inflammatory markers. The mean VAS for back and leg pain before ALIF was 6.8±1.1, which improved to 3.2±2.2 at 6 months after ALIF. The mean ODI score before ALIF was 70.0±14.8, which improved to 34.2±27.0 at 6 months after ALIF. Successful bony fusion rate was 84.6% (11/13) and the remaining two patients were also asymptomatic.
Our results suggest that ALIF is an effective treatment option for postoperative spondylodiscitis.
Postoperative spondylodiscitis is among the lethal complications of spinal surgery. This condition results mostly from inoculation of microbes through the incision line during posterior approach to the spine. In many cases, this inoculation primarily infects the intervertebral disc and subsequently spreads to the adjacent vertebral structures
From January, 1994 to August, 2013, 13251 patients received spinal surgeries at our institute. Among them, 82 (0.62%) suffered postoperative spondylodiscitis, and ALIF was done in 13 patients. Therefore, the study population consisted of 13 consecutive patients with postoperative spondylodiscitis who were treated with ALIF. Postoperative spondylodiscitis was suspected when the patients had symptoms and signs suggestive of local infection, including fever, progression of local pain, and redness or edema at the operation site. Diagnostic measures are composed of laboratory findings, X-ray, and contrast-enhanced MRI. To treat postoperative spondylodiscitis, we first tried non-operative methods such as administrating antibiotics for 6-8 weeks. However, whenever the infection was so progressive that it was insufficient to treat by antibiotics alone, such as epidural abscesses or neural compression, we operated as soon as possible.
The immediate postoperative assessment consisted of physical examination and radiologic evaluation. The Oswestry Disability Index (ODI) was used for assessment of quality of life, and the modified Visual Analogue Scale (VAS) for assessment of pain. These parameters were measured before and 6 months after the ALIF. Serial spine X-rays that included dynamic flexion-extension views were used to assess radiologic outcomes. The successful fusion was defined as : 1) absence of halo around the screws; 2) presence of bilateral continuous trabecular bone bridge between the fused segments on the anteroposterior plain film; and 3) lack of motion on the flexion-extension film. The successful fusion was confirmed by the attending surgeon using these parameters
Patients were positioned supine on the operating table with their arms abducted on arm boards. After a paramedian "minilaparotomy" was performed, location of the aortic bifurcation, the vena cava, and iliac arteries and veins were identified after anterior retroperitoneal approach. Cauterization was avoided near the presacral sympathetic plexus. The great vessels and their tributaries were mobilized to provide exposure of the disc space. For L5-S1 level, the midline sacral vessels were ligated, and the iliac arteries and veins were mobilized. For L3-4, L4-5 level, the iliolumbar and segmental vessels were ligated, and the aorta and vena cava were mobilized to expose the entire ventral surface of the disc space. After the infected and adhered anterior surface of the spine was exposed, a rectangular incision was made anteriorly in the annulus fibrosus, followed by a discectomy at that level. Once the ventral dura was exposed, infected tissue was debrided completely and irrigated sufficiently. After compete removal of the infected tissue, interbody fusion was performed with autologous tricortical iliac bone block or interbody fusion cages packed with autologous cancellous bone. The operative wound was closed layer by layer in a routine fashion.
All analyses were performed with Statistical Package for the Social Sciences (SPSS) version 18.0 (SPSS Inc., Chicago, IL, USA). Continuous variables are presented as mean±SD, and categorical variables are presented as frequencies. Paired t-tests and chi-square tests were used to compare pre- and post-operative values. All
The baseline characteristics, surgical indications, and clinical outcomes are summarized in
Among the 13 total patients, 10 had revision surgery within 1 year after the primary surgery; three had revision surgery 1-3 years after the primary surgery. The mean interval from the primary surgery to ALIF was 7.8 months (1-23 months), and the average duration of symptoms before ALIF was 2.1 months (1-5 months). The mean interval from the primary surgery to postoperative spondylodiscitis was 5.8 months (1-22 months). After ALIF, the patients were followed up for an average of 112 months (8-234 months).
The 13 patients underwent surgery on a total of 15 segments. Eleven patients underwent single-level fusion, and two patients underwent two-level fusions. The levels fused included L5-S1 (4 cases), L4-5 (9 cases), and L3-4 (2 cases). Decisions regarding the surgical levels fused were made at the attending surgeon's discretion. Autologous tricortical bone block was used in cases with endplate destruction from the discitis, whereas interbody fusion cages were used in cases without endplate destruction after the antimicrobial therapy. The autologous iliac bone block was used as the interbody fusion material in 10 out of 13 cases. Titanium threaded cages were used in the other three cases.
Bacterial pathogens were identified in seven out of 13 patients (53.8%). One patient was co-infected with fungus. The most common pathogens were
In the laboratory findings, the initial average erythrocyte sedimentation rate (ESR) level was 42.2±28.8 mm/h (0-15 mm/h), C-reactive protein (CRP) level was 61.1±69.4 mg/L (0-5.3 mg/L), and the leukocyte count was 9152±4111/mm3. Initial intravenous (IV) antibiotic therapy was started immediately after the clinical diagnosis was made. The average duration of intravenous antibiotic therapy in the study population was 8 weeks (4-15 weeks) after the ALIF. After 6 months, inflammatory markers (WBC, ESR, and CRP) were within the normal range for all patients.
Mean VAS for back and leg pain before ALIF was 6.8±1.1, which improved to 3.2±2.2 after ALIF (
There were no specific post-ALIF complications during the follow-up in the study population.
Early treatment of postoperative spondylodiscitis usually consists of bed rest, immobilization, and broad-spectrum antibiotics. For advanced disease, a posterior approach such as laminectomy has been considered a standard procedure
This retrospective analysis revealed that ALIF led to successful management of postoperative spondylodiscitis in terms of infection control and symptom improvement. In addition, ALIF provided optimal symptomatic improvement and stabilization of the vertebrae in most cases
The goals of treatment for postoperative spondylodiscitis are as follow : 1) eradicate the infected tissue, 2) prevent neurological damage, 3) restore spinal balance, and 4) relieve pain
The primary limitation of the current study was its retrospective design. For this reason, indications of surgery, antibiotic treatment, and general care of patients varied from surgeon to surgeon, and the independent impact of ALIF on the management of postoperative spondylodiscitis could not be verified. In addition, this study focused only on a descriptive analysis of ALIF without a control group; thus, we cannot firmly state that ALIF is better or even equivalent to traditional posterior approaches. Although the recruiting period spanned two decades, only 13 patients could be enrolled, which limits the generalization and the prospectiveness of this study.
ALIF has many benefits over the posterior approach, including lessening damage to the paraspinal structures, providing a wider fusion bed for better arthrodesis, and more effective restoration of the vertebral balance. Our data suggest that ALIF might be an effective treatment for postoperative spondylodiscitis.
A 36-year-old man with psoas muscle abscess. One month previously, he had undergone total disc replacement at L4-5 at another hospital. One month after the surgery, he was referred to our hospital for new-onset back pain and fever. A : The initial X-ray. B : Pre-contrast T1-weighted sagittal. C : T2-weighted sagittal. D : Post-contrast T1-weighted sagittal MRI scan showed bony destruction of L4 and L5 vertebral bodies. E : post-contrast T1-weighted axial MRI scan showed extensive paravertebral and psoas abscess (arrow). He underwent debridement of the infected tissue along with ALIF using an autologous tricortical iliac bone graft. F : The follow-up X-ray showed successful bony fusion and appropriate sagittal alignment.
Patient characteristics
*Autograft means autologous tricortical iliac bone block. Cage means interbody fusion cages packed with autologous cancellous bone. OP : operation, Sx : Symptom, VAS : visual analogue scale, ODI : Oswestry disability Index, TB : tuberculosis, DM : diabetes mellitus, HTN : hypertension, CAOD : coronary artery occlusive disease, PHL : partial hemilaminectomy, DL : decompressive laminectomy, PLIF : posterior lumbar interbody fusion, WR : wound revision, ADR : artificial disc replacement, MRSA : methicillin-resistant