Conservative therapy with sensitive antibiotics and bracing is adequate for most patients with infectious spondylitis. A delay in diagnosis and treatment is common in all forms of spinal infection because of their early indolent course
[1–4]. Rezai et al. reported that 25% of patients who were initially treated nonsurgically had unsuccessful medial therapy
. Surgical intervention is typically reserved for patients with failed antibiotics therapy, intractable back pain, significant neurological deficit, large epidural abscesses, extensive vertebral body destruction, severe kyphotic deformity, or spinal instability
[22–25]. However, major spinal surgery consisting of anterior debridement and bone grafting with or without supplemental instrumentation is often related to undesired postoperative complications.
Several minimally invasive methods have been used to treat infectious spondylitis. Computed tomography-guided percutaneous catheter drainage has been approved as an efficient and safe procedure in the management of early-stage spondylodiscitis
. Haaker et al. treated 16 patients with spondylodiscitis by using percutaneous lumbar discectomy. They concluded that it is a useful and minimally invasive technique for the conservative treatment of lumbar discitis, although the causative pathogens could be identified in only 45% of the cases
. Percutaneous suction, aspiration, drainage, and continuous irrigation with local administration of antibiotics have also been found to be effective in patients with early-stage pyogenic spondylitis and even spinal infection accompanied by iliopsoas abscesses
[28–31]. However, the continuous irrigation method restrained the patients to their beds and limited their postoperative ambulation and activities.
The minimal invasiveness and simplicity of PED have led the authors to apply it as a modality for treating patients with infectious spondylitis. Direct endoscopic observation makes possible the direct collection of sufficient amounts of samples from the infected region for microbiological examination. Eradication and debridement of the infected and necrotic tissue from a disc and even an epidural space can be achieved under endoscopic monitoring. During the irrigation procedure, the disc debris and turbid abscess can be washed out by dilute betadine solution through the suction sheath. Moreover, postoperative negative-pressure Hemovac drainage in larger-diameter can continuously suck out the pathogens from the infected area. A combination of effective debridement with dilute betadine solution irrigation and full-course specific antimicrobial therapy resulted in favorable outcomes in current study.
Povidone-iodine is a widely used antiseptic and disinfectant agent. It can eradicate most pathogens, including oxacillin resistant staphylococcus aureus, and no bacterial resistance has been reported
[14–18]. In an experimental research, Kaysinger et al. found that the inhibitory effect of betadine on embryo chick tibia and osteoblast cells is significant at concentrations of 5% betadine or higher
. In contrast, few cytotoxic effects were observed at a lower concentration (0.5% betadine). Goldenheim reported that 1%, 5%, or 10% povidone-iodine preparations do not have a deleterious effect on wound healing in animals and humans
. In a clinical study
, spinal surgical wounds were soaked with dilute betadine solution before wound closure, and outcomes were compared with those of irrigation with normal saline. A 10% povidone-iodine solution was diluted to achieve a concentration of 3.5% betadine, possessing maximal bactericidal activity and minimal cytotoxicity. No wound infection occurred in patients who received betadine irrigation during the follow-up period.
Twenty-six patients with infectious spondylitis were successfully treated with PEDI in this series. This minimally invasive technique produces less morbidity than open surgery and provides effective relief to the patient’s back pain by reducing the intradiscal pressure and preserving adequate stability. These patients could ambulate with brace protection as early as possible after PEDI. Patients who sustained epidural or paraspinal abscesses could also be treated by this method and avoid having to undergo open anterior or posterior decompression surgery. A connection generally exists between these abscesses and the infected disc, which is the actual origin of spinal infection. After aggressive debridement of the infected disc and neighboring vertebral endplates, a cavity was created and even the sticky abscesses could be washed out by pressurized irrigation with betadine solution. With postoperative negative-pressure Hemovac suction, the pathogens in the infected tissue can be removed continually.
Six patients eventually underwent open surgery for poorly controlled infections and considerable mechanical back pain caused by progressive destruction. Three of 4 patients with multilevel infections who experience medical therapy failure received open anterior debridement and autograft interbody fusion with supplemental posterior fixation. Only 1 elderly patient with 2-level infections responded to PEDI. However, this patient still complained of mild back soreness with progressive kyphotic deformity. Therefore, the effectiveness of this procedure for extensive destruction of vertebral bodies and multilevel infections may be limited, from the viewpoint of either surgical technique or clinical prognosis.
This study has several limitations. First, we examined only 32 cases. Second, the retrospective nature of this study does not allow including patients undergoing different treatment methods for comparison, as well as lacks randomization because of ethical and legal considerations. The feasibility and benefits of PEDI for infectious spondylitis need to be rigorously evaluated in a large patient population with prospectively controlled comparison groups. Third, the enrolled patients had different kinds of spinal infections, such as early-stage infection or advanced infection, single-level infectious spondylodiscitis or multilevel infections, and spinal infection with or without epidural or paraspinal abscess. Thus, careful classification of patients through meticulous clinical examination and comprehensive image studies can further evaluate the efficacy and indications of this procedure in different stages and severities of spinal infection.