LPD diagnosis can be very difficult, especially in a resource-poor environment. This challenge stems from the relative rarity of the disease, a much higher incidence of non-specific back pain in the whole population, changes in protein expression, non-pathogenic imaging and positive rates from culture[11–12]. The main means of diagnosis are spinal imaging and spinal biopsy materials for microbiological examination and ideal histopathology. In any infectious disease, the therapy should be based on the results of culture and in vitro susceptibility testing. According to Infectious Diseases Society of America(IDSA) clinical practice guideline for the diagnosis and treatment of native vertebral osteomyelitis in adults, LPD is frequently monomicrobial and most often due to Staphylococcus aureus[5–6, 13–14]. The local administration of VCM was usually performed for better control of infection. However, in our study, although blood culture isolated the bacterium, the positive culture rate was 35.2% in group A and 20% in group B, but there were no findings in the stool, urine or surgical material culture[15–16]. There were only 3 cases of Staphylococcus aureus in the two groups. Perhaps because the regimens of antibiotic therapy and the methods of administration were empirical, in the study, the mean times of antibiotic therapy before surgery, which were 17.62 ± 3.76 days in group A and 13.86 ± 4.71 days in group B, could explain why we had more difficulty with the diagnosis as well as the morbidity and mortality of effective treatment, and the culture positive rate was low.
Most patients are cured with a course of 6 weeks or more of antimicrobial therapy, but a few patients may need surgical debridement and/or spinal reconstruction during or after antimicrobial therapy. After complete lesion debridement, numerous interbody bone grafts are applied to recover and reconstruct spinal stability[17–19]. Titanium mesh cages(TMCs) filled with autologous bone grafts have been widely applied and could achieve high bony fusion rates. However, the surgical planning and results could be affected by the subsidence, stress shielding, and radio-opacity. Thus, our research aimed to find a new bone graft that could provide biomechanical support and achieve bony fusion to reduce the incidence of complications. The use of a LSP as the bone graft has several advantages. Firstly, compared with the IG, the LSP were more minimally invasive, shorten the surgery time, and reduce postoperative complication rates. Secondly, in the study, the mean time of bone fusion was 11.30 ± 4.751 months in group A, which was longer than that in group B (6.80 ± 1.50). Although the LSP gained a longer time of bone healing, with the correction of segmental kyphosis, there was no significance among the groups. Hence, the LSP could provide excellent biomechanical support, strength, and bone fusion properties. Furthermore, the LSP, as an autologous bone graft, has a cortical bony structure supporting the bone defect space and can ensure and maintain segmental stability and alignment. After the surgery, the VAS and ODI scores were improved significantly, which improved the life quality of the patients.
Although the diagnosis of LPD is very difficult, some clues can be identified: severe low back pain, fever, increasing infection indexes, magnetic resonance imaging (MRI), C-arm-guided biopsy, and clear pathogenic bacteria from cultures[17–18, 21–23]. However, there is a50% misdiagnosis rate,and pathological findings are still the gold standard despite the culture of blood, urine, stool, or surgical tissue being negative. MRI is considered the modalityof choice for radiographic diagnosis, especially in severe lower back pain. Previous studies have reported an MRI sensitivity of 96%, a specificity of 93% and an accuracy of 94% in LPD, and MRI plays the key role in the continuous observation of LPD[24–27].
However, we declare that the study had a few limitations. First, the retrospective natureof the small-sample study may be associated with bias, more patients need to be included in the study. Second, the single LSP as a bone graft had a long bony fusion time and may be a risk factor for the delay of bony fusion.Third, the study did not consider intra- or inter-observer differences, which was associated with bias. In the future, prospective, randomized studies with long-term follow-up periods are needed.