Implementation of a multidisciplinary infections conference improves the treatment of spondylodiscitis.

Establishing a multidisciplinary approach regarding the treatment of spondylodiscitis and analyzing its effect compared to a single discipline approach. 361 patients diagnosed with spondylodiscitis were included in this retrospective pre-post intervention study. The treatment strategy was either established by a single discipline approach (n = 149, year 2003-2011) or by a weekly multidisciplinary infections conference (n = 212, year 2013-2018) consisting of at least an orthopedic surgeon, medical microbiologist, infectious disease specialist and pathologist. Recorded data included the surgical and antibiotic strategy, complications leading to operative revision, recovered microorganisms, as well as the total length of hospital and intensive care unit stay. Compared to a single discipline approach, performing the multidisciplinary infections conference led to significant changes in anti-infective and surgical treatment strategies. Patients discussed in the conference showed significantly reduced days of total antibiotic treatment (66 ± 31 vs 104 ± 31, p < 0.001). Moreover, one stage procedures and open transpedicular screw placement were more frequently performed following multidisciplinary discussions, while there were less involved spinal segments in terms of internal fixation as well as an increased use of intervertebral cages instead of autologous bone graft (p < 0.001). Staphylococcus aureus and Staphylococcus epidermidis were the most frequently recovered organisms in both patient groups. No significant difference was found comparing inpatient complications between the two groups or the total in-hospital stay. Implementation of a weekly infections conference is an effective approach to introduce multidisciplinarity into spondylodiscitis management. These conferences significantly altered the treatment plan compared to a single discipline approach. Therefore, we highly recommend the implementation to optimize treatment modalities for patients.

The effects of different antiseptic mouthwash on microbiota around orthodontic mini-screw.

OBJECTIVE: This study aims to investigate the effects of different antiseptic mouthwash on microbiota around the mini-screw applied to patients undergoing fixed orthodontic treatment. MATERIALS AND METHODS: From patients who have been undergoing fixed orthodontic treatment and who have mini-screws in their mouth, a total of 38 patients were selected for the study consisting of 4 groups, each of which has 15 mini-screws. The patients were selected from the following groups: no use of mouthwash (Group 1), use of 0.12% chlorhexidine gluconate-containing mouthwash (Group 2), use of essential oils-containing mouthwash (Group 3), and use of 7.5% povidone-iodine-containing mouthwash (Group 4). Plaque indices and gingival indices of the patients were measured at the beginning (T0) and at their appointments 3 weeks later (T1). In addition, biological samples were collected from the sulcus around the mini-screw with the help of sterile paper point. RESULTS: The total number of microorganisms around the mini-screw in Group 2, Group 3, and Group 4 decreased significantly compared to Group 1. A significant decrease in Streptococcus oralis, Streptococcus mitis, Candida parapsilosis, total bacteria, plaque index, and gingival index count was observed in T1compared to T0. CONCLUSION: Antiseptic mouthwash in Group 2, Group 3, and Group 4 can be used to reduce the number of microbial microbiota around the mini-screw and to improve oral hygiene.

Burkholderia pseudomallei peri-prosthetic infection following medial malleolar internal fixation: a case report.

BACKGROUND: Melioidosis-associated peri-prosthetic infection is extremely rare. To date, melioidosis associated septic arthritis of the ankle joint following a medial malleolar internal fixation has not been reported. CASE PRESENTATION: We describe a 49-year-old male with a history of long standing diabetes who presented with fever, constitutional symptoms and right ankle pain for 1 week. Ten years ago, he underwent a medial malleolar screw fixation following a traumatic closed fracture. His initial right ankle radiographs showed no evidence of osteomyelitis. He underwent a wound debridement and washout of the right ankle joint. The peripheral blood and pus from the ankle joint was culture positive for Burkholderia pseudomallei with very high antibody titres. His subsequent radiographs showed features of chronic osteomyelitis. He was treated with a prolonged course of antibiotics and repeated wound debridement. At follow up after 6 months, he had no clinical features of recurrent infection. CONCLUSIONS: Melioidosis should be entertained in the differential diagnosis of peri-prosthetic infections in high risk patients.

Sealing agent reduces formation of single and dual-species biofilms of Candida albicans and Enterococcus faecalis on screw joints at the abutment/implant interface.

The aim of this research was to evaluate the efficacy of a commercial sealing agent at the abutment/implant interface against microleakage of single and dual-species biofilms of Candida albicans and Enterococcus faecalis into external hexagon (EH) and Morse taper (MT) prosthetic connections. A total of 216 samples of implants and their abutments were tested. Six groups (n = 36) were evaluated based on biofilm and period of incubation (7 and 14 days). The implant connections EH and MT (n = 18) were divided according to the use of the material (n = 9) (EH-T and MT-T: with the sealing agent; EH-C and MT-C: control). The biofilms were analyzed by microbial counting (CFU/mL) and SEM analysis and photographs of the material in the screw joints were also taken. Data were analyzed by Student t test, two-way ANOVA and Bonferroni test. For the single-species biofilms, there was a significant reduction in the growth of E. faecalis when compared MT-C and MT-T or EH-C and EH-T at 7 and 14 days. The same was observed for C. albicans biofilms. For dual-species biofilms of E. faecalis and C. albicans, the sealing agent was more effective in preventing microbial infiltration into the MT connection at 14 days, while microbial infiltration did not occur into EH connections even in absence of the sealing agent for both periods of evaluation. Overall, these data suggest that the presence of the sealing agent reduces or eliminates the microleakage of E. faecalis and C. albicans biofilms into the implants regardless of the period of incubation.

Delayed onset bioabsorbable screw reaction, intact screw extrusion and Pseudomonas aeruginosa tibial tunnel osteomyelitis years after arthroscopic anterior cruciate ligament reconstruction using hamstring graft.

Postoperative reaction and infection after anterior cruciate ligament (ACL) reconstruction is a rare complication. We report two cases of bioabsorbable screw extrusion and Pseudomonas aeruginosa tibial tunnel infection in 17/18-year-old men, 2 and 4 years after ACL reconstruction, respectively. They underwent tibial tunnel debridement, removal of the still intact poly-L-D-lactic acid bioabsorbable screw and subsequent wound closure. Physical examination findings confirmed patency of the hamstring graft. Culture guided antibiotics were completed, and wounds healed unremarkably. Both returned to previous level of activity. Successful treatment is achieved through a logical sequence of management, as well as a multidisciplinary approach to prevent unnecessary secondary procedures and morbidity.

Successive complications after anterior cervical fixation: pharyngoesophageal diverticulum, fistulization, and cervical spondylitis by Streptococcus milleri - case report and literature review.

INTRODUCTION: Pharyngoesophageal diverticulum is an uncommon complication after anterior cervical discectomy and fusion surgery. CASE PRESENTATION: Our patient was a 48-year-old woman with two previous cervical surgeries with fixation of C4-C5 and C5-C6, the last one in 2003. Two years after surgery, she presented with arthralgia, arthritis, chills, and fluctuating rash. In 2007, she presented with dysphagia, halitosis, and sputum production. She was diagnosed with a pharyngoesophageal diverticulum with a fistula to C6 vertebra and secondary spondylitis. She was taken for open surgery with removal of screws and plates, cricopharyngeal myotomy, and esophageal repair. Streptococcus milleri grew in tissue and osteosynthetic material. She received 4 months of amoxicillin and probenecid and had a complete recovery. Since 1991, 19 similar cases have been reported with one fatality. To our knowledge, this is the first reported case of diverticulum complicated with fistula and secondary spondylitis. CONCLUSIONS: In patients with a history of anterior cervical discectomy and fusion complaining of dysphagia, even years after surgery, it is mandatory to perform an esophagogram. This symptom was referred to in 88% of the cases reported in the literature.

Growth of Cutibacterium acnes is common on osteosynthesis material of the shoulder in patients without signs of infection.

Background and purpose - Cutibacterium acnes, formerly known as Propionibacterium acnes, is often isolated from deep tissues of the shoulder. It is recognized as an important causative agent of foreign-material associated infections. However, the incidence and significance of its detection in tissues from patients without clinical evidence for infection is unclear. We assessed the incidence of C. acnes colonization of osteosynthesis material in asymptomatic patients, and evaluated the short-term outcome in relation to the microbiological findings. Patients and methods - We microbiologically analyzed osteosynthesis material of 34 asymptomatic patients after surgery on the clavicle. Material obtained from 19 asymptomatic patients after osteosynthesis of the fibula served as a control group. Patients were clinically followed up for 3-24 months after removal of the osteosynthesis material. Results - Bacteria were recovered from devices in 29 of 34 patients from the clavicle group. 27 of 29 positive samples grew C. acnes. Isolation of C. acnes was more common in male than in female patients. No bacterial growth was observed on foreign material from patients in the fibula group. All patients remained asymptomatic at follow-up. Interpretation - Growth of C. acnes is common on osteosynthesis material of the shoulder, especially in males. Samples were positive irrespective of clinical signs of infection. Therefore, detection of C. acnes in this clinical setting is of questionable clinical significance. The high positivity rate in asymptomatic patients discourages routine sampling of material in cases without clinical evidence for infection.

Bacteriological aspects of chronic osteoarticular infections in adults: the influence of the osteosynthesis material.

BACKGROUND: The aim of this study is to establish the bacterial epidemiology of chronic osteoarticular infections in adults, to study the susceptibility of the isolated strains to antibiotics and to demonstrate the influence of osteosynthesis material thereon. PATIENTS AND METHODS: This is a retrospective study of 78 months, from January 2006 to June 2012, providing bacteriological samples from patients with osteitis and osteoarthritis in the Mohammed V military teaching hospital of Rabat. Isolation and identification of bacteria were made by bacteriological classical techniques. The antimicrobial susceptibility testing of the isolates was performed by disk diffusion agar method, as recommended by the Committee of the susceptibility of the French Society for Microbiology (CA-SFM). RESULTS: We collected 234 cases, 53% (n = 124) of patients without osteosynthesis material (group A) and 47% (n = 110) patients with osteosynthesis material (group B).We isolated 371 bacteria which 51.49 (n = 191) in group A and 48.51% (n = 180) in group B. Gram-positive cocci were the most frequent (n = 234), followed by the Gram-negative bacilli (n = 114) and the Gram-positive bacilli (n = 19). Our study shows that the rate of resistance to antibiotics in strains obtained from patients with osteosynthesis material is higher compared to those obtained from patients without osteosynthesis material. CONCLUSIONS: Chronic OA infection in adults is difficult to diagnose and treat. Its good management must be multidisciplinary.

High incidence of periprosthetic joint infection with propionibacterium acnes after the use of a stemless shoulder prosthesis with metaphyseal screw fixation - a retrospective cohort study of 241 patients.

BACKGROUND: A stemless shoulder prosthesis with humeral metaphyseal screw fixation was introduced in order to save bone-stock and to facilitate reconstruction of biomechanics (Eclipse®). The aim of this study was to analyze whether the risk of infection is different with this implant compared to conventional shoulder prosthesis. METHODS: Two hundred and forty-one patients (54.8% females) were operated with a shoulder arthroplasty and followed for median 2.0 (0.1-5.7) years. One hundred and two (42.3%) had received an Eclipse® prosthesis, the remaining patients were operated with other implants. There was an overrepresentation of males in the Eclipse® group (63.7% males) when compared with the control group (31.7% males). RESULTS: In the Eclipse® group 10 (9.8%) patients developed a periprosthetic joint infection, as opposed to 1 (0.7%) in the control group. The most common bacteria was Propionibacterium acnes. Unadjusted infection-free survival after 4 years was 88.8% (CI 82.5-95.7) for Eclipse® patients and 95.7% (CI 87.7-100.0) for controls (p = 0.002). After adjustment for age, gender, diagnosis, and type of shoulder prosthesis (total or hemi), the risk ratio for revision due to infection was 4.3 (CI 0.5-39.1) for patients with the Eclipse® prosthesis. CONCLUSIONS: Deep infections seem to be more common after the use of the metaphyseally fixed Eclipse® prosthesis than after conventional shoulder implants, but a predominance of male gender and younger age in the Eclipse group may have biased our findings. Future studies on larger cohorts and in vitro investigations on bacterial adherence and biofilm formation are needed. TRIAL REGISTRATION: The study was conducted in accordance with the Helsinki Declaration. The local ethics board (Regionala Etikprövningsnämnden Stockholm) approved the study (Approval number 2015/1590-31, date of issue 2015-10-14). Retrospectively registered.

A new model of implant-related osteomyelitis in the metaphysis of rat tibiae.

BACKGROUND: Animal models serve as an important tool to understand peri-implant infection. Most of the models use high bacterial loads (>10(4) colony forming units, CFU) to provide high infection rates. Therefore these animals evolve rather similarly, making comparison between groups and statistical analysis possible. On the other hand, to mimic clinical constellation of surgery-related infections the use of low amounts of bacteria would be more advantageous. METHODS: We developed a metaphyseal rat model of peri-implant bone infection with low amount of bacterial loads (10(2) and 10(3) CFU of Staphylococcus aureus) and investigated osseointegration of the implants coated with hydroxyapatite (HA) and low-dosed HA-silver (HA-Ag). Non-infected implants served as controls. After 6 weeks rats were sacrificed and implants evaluated for osseointegration and infection. RESULTS: Infection of implanted devices was reliably induced, independently whether 10(2) or 10(3) CFU of S. aureus were inoculated and HA or HA-Ag coated implants were used. No systemic infection was present in any of the animals at the time of sacrifice, and no animal developed acute infection requiring premature sacrifice. All CFU counts of the implant and the bone at sacrifice were significantly higher than the inoculated load (p < .05). All sterilely inserted implants showed excellent osseointegration and no infection. CONCLUSIONS: Our present study of a rat tibia model reliably induced osteomyelitis in the metaphysis with low-doses of bacteria. The addition of low-dosed Ag to the implant coating was not able to reduce the infection rates. The results demonstrate that it is possible to develop a model of implant-related osteomyelitis in rats with low amounts of bacteria to better mimic clinical constellations. No other promoters of infection besides insertion of the screw implant were used in this model.

High complication rate after syndesmotic screw removal.

PURPOSE: The aim of this study was to determine the rate of complications after routine syndesmotic screw removal. MATERIALS AND METHODS: All patients who underwent syndesmotic screw removal at our hospital between 2007 and 2012 were included in the study. Patient demographics, surgical characteristics, radiographic evaluation and complications were recorded from the patients' charts. Questionnaires were sent by postal mail to all patients, to measure patient satisfaction and pain (VAS scales). RESULTS: 161 patients were included in the trial. A wound infection was found in 8 (5%) patients. 3 were regarded as serious infections requiring hospitalisation and intravenous antibiotics, 2 of those required surgical revisions. 5 patients were treated by oral antibiotics. Staphylococcus aureus was identified as the causing organism in all (6/8) cases with a positive culture. The patients with postoperative infection reported more pain (5.3 vs. 2.3; p=0.02) and were less satisfied (4.7 vs. 7.6; p=0.014) with their ankle compared to those without infection (T-test for independent samples). CONCLUSION: There were 5% wound infections after routine syndesmotic screw removal. Routine antibiotic prophylaxis effective against S. aureus should be administered when removing syndesmotic screws. In our institution we now use one single dose Cefalotin of 2g intravenously 30-60min before screw removal.

Two-Stage Revision Arthroplasty for Periprosthetic Hip Infection: Mean Follow-Up of Ten Years.

BACKGROUND: Two-stage revision hip arthroplasty is the gold standard for treatment of patients with chronic periprosthetic joint infection (PJI), but few studies have reported outcomes beyond short-term follow-up. METHODS: A total of 155 patients who underwent two-stage revision arthroplasty for chronic PJI in 157 hips were retrospectively enrolled in this study between January 2001 and December 2010. The mean patient age was 57.5 years, the mean prosthetic age was 3.6 years, and the interim interval was 17.8 weeks. These patients were followed up for an average of 9.7 years. RESULTS: At the latest follow-up, 91.7% of the patients were free of infection. The mean Harris hip score improved significantly from 28.3 points before operation to 85.7 points at the latest follow-up. Radiographically, there was aseptic loosening of the stem or acetabular components in 4 patients. In the multivariate survival analysis using a Cox regression model, repeated debridement before final reconstruction, an inadequate interim period, bacteriuria or pyuria, and cirrhosis were found to be the independent risk factors for treatment failure. CONCLUSION: Our data show that two-stage revision hip arthroplasty provides reliable eradication of infection and durable reconstruction of the joint in patients with PJI caused by a variety of pathogens.

In Vivo MicroCT Monitoring of Osteomyelitis in a Rat Model.

Infection associated with orthopedic implants often results in bone loss and requires surgical removal of the implant. The aim of this study was to evaluate morphological changes of bone adjacent to a bacteria-colonized implant, with the aim of identifying temporal patterns that are characteristic of infection. In an in vivo study with rats, bone changes were assessed using in vivo microCT at 7 time points during a one-month postoperative period. The rats received either a sterile or Staphylococcus aureus-colonized polyetheretherketone screw in the tibia. Bone-implant contact, bone fraction, and bone changes (quiescent, resorbed, and new bone) were calculated from consecutive scans and validated against histomorphometry. The screw pullout strength was estimated from FE models and the results were validated against mechanical testing. In the sterile group, bone-implant contact, bone fraction, and mechanical fixation increased steadily until day 14 and then plateaued. In the infected group, they decreased rapidly. Bone formation was reduced while resorption was increased, with maximum effects observed within 6 days. In summary, the model presented is capable of evaluating the patterns of bone changes due to implant-related infections. The combined use of longitudinal in vivo microCT imaging and image-based finite element analysis provides characteristic signs of infection within 6 days.

Inhibition of adherence of C. albicans to dental implants and cover screws by Cymbopogon nardus essential oil and citronellal.

OBJECTIVE: This study investigated the biological activity of the essential oil from Cymbopogon nardus and of the phytoconstituent citronellal on Candida strains as to the inhibition of adherence to dental implants and cover screws. MATERIAL AND METHODS: The essential oil was analyzed by gas chromatography coupled to mass spectrometry (GC-MS) and had its MIC and MFC determined against 12 strains of Candida. Then, tests of inhibition of adherence to the dental implants and cover screws were carried out using the MIC of the substances, followed by scanning electron microscopy analysis. Nystatin and chlorhexidine were used as positive controls, and experiments were performed in triplicate. RESULTS: The analysis by GC-MS of the essential oil identified citronellal as the major compound. The MICs of the essential oil, citronellal, chlorhexidine, and nystatin--able to inhibit 100 % of the strains--were found to be 64, 512, 64, and 32 µg/ml, respectively. The essential oil significantly inhibited the adherence of Candida albicans to the dental implants and cover screws (p < 0.001). Citronellal inhibited yeast adherence only to the dental implants (p < 0.001), and no significant results were found for the cover screws (p > 0.05) compared to the growth control. CONCLUSION: The essential oil and citronellal have proven antifungal activity and are able to inhibit the in vitro adherence of C. albicans. CLINICAL RELEVANCE: There has been a search for alternative natural product-containing formulations that should be effective in inhibiting adherence of yeasts to the surfaces of materials and also able to treat oral fungal infections. Further trials could make these products an alternative to chemical removal of peri-implant biofilm.

Postoperative wound infection after posterior spinal instrumentation: analysis of long-term treatment outcomes.

PURPOSE: Postoperative spinal implant infection (PSII) places patients at risk for pseudarthrosis, correction loss, spondylodiscitis, adverse neurological sequelae, and even death; however, prognostic factors that predict long-term treatment outcomes have not been clearly investigated. In addition, few studies concerning the feasibility of reconstructing the failed spinal events have been published. METHODS: We performed a cohort study of 51 patients who contracted PSII in the posterolateral thoracolumbar region at a single tertiary center between March 1997 and May 2007. Forty-seven patients (92.2 %) had one or more medical problems. Isolated bacterial species, infection severity, treatment timing, and hosts' defense response were evaluated to assess their relationship with management outcomes. The use of implant salvage, or removal subsequent with a revision strategy depended on the patient's general conditions, infection control, and implant status for fusion. RESULTS: The most common infective culprit was Staphylococcus spp. found in 35 of 60 (58.3 %) isolates, including 20 methicillin-resistant species. Gram-negative bacilli and polymicrobial infection were found significantly in patients presenting early-onset, deep-site infection and myonecrosis. Prompt diagnosis and aggressive therapy were responsible for implant preservation in 41 of 51 cases (80.4 %), while implant removal noted in 10 cases (19.6 %) was attributed to delayed treatment and uncontrolled infection with implant loosening, correction loss, or late infection with spondylodesis. The number of employed debridements alone was not significantly correlated with successful implant preservation. Delayed treatment for infection >3 months significantly led to implant removal (p < 0.05) and a higher number of failed spinal events. Patients with significant comorbidities, malnutrition, severe trauma, neurological deficits, long-level instrumentation, and delayed treatment had poor outcomes. Sixteen patients (31.4 %) exhibited probable nonunion or pseudarthrosis, and eight symptomatic patients among them underwent successful revision surgery. CONCLUSIONS: Retention of the mechanically sound implants in early-onset infection permits fusion to occur, while delayed treatment, severe malnutrition and multiple comorbidities will most likely result in a lack of effectiveness in eradicating the infecting pathogens. Restoring optimal physiological conditions is imperative in high-risk patients to allow for further healing. When loosened screws cause peridiscal erosion and incapacitating motion pain, premature implant removal possibly results in failed fusion and correction loss. Reconstruction for a failed spinal event is feasible following infection control.

Antibacterial properties of magnesium in vitro and in an in vivo model of implant-associated methicillin-resistant Staphylococcus aureus infection.

Periprosthetic infection remains a challenging clinical complication. We investigated the antibacterial properties of pure (99.9%) magnesium (Mg) in vitro and in an in vivo rat model of implant-related infection. Mg was highly effective against methicillin-resistant Staphylococcus aureus-induced osteomyelitis and improved new peri-implant bone formation. Bacterial icaA and agr RNAIII transcription levels were also assessed to characterize the mechanism underlying the antibacterial properties of the Mg implant.

A scanning electron microscope characterisation of biofilm on failed craniofacial osteosynthesis miniplates.

INTRODUCTION: Between 3 and 18% of craniofacial osteosynthesis plates are removed due to chronic infection. Removal of the plate is necessary to manage the chronic infective state i.e. miniplate removal results in resolution of the infection. These observations are suggestive of a biofilm-related infection. The aim of this retrospective study was to characterise the presence of biofilm on the removed miniplates from oral and maxillofacial surgery. MATERIALS AND METHODS: A total of 12 plates and associated screws were recovered from eleven patients suffering from persistent, trauma site infection. The recovered plates plus 1 control plate were imaged using scanning electron microscopy (SEM). One recovered plate was also imaged using confocal microscopy (CM) for comparative purposes. RESULTS: Of the 12 plates, 3 (25%) demonstrated highly localised polymicrobial biofilms, five (42%) demonstrated coccal biofilms, one possessed a filamentous biofilm and one showed attached yeast. Overall, 75% of the plates and 82% of the patients exhibited evidence of biofilm to varying degrees. All of the infections resolved following removal of the plates and antibiotic treatment. CONCLUSION: Microbial biofilms can explain the clinical course of chronic infections associated with miniplates.

Remission rate of implant-related infections following revision surgery after fractures.

PURPOSE: In contrast to a large amount of epidemiological data regarding the incidence of implant infections after fracture management, surprisingly few have been published concerning the success of their treatment. METHODS: This was a single-centre cohort study at Geneva University Hospitals from 2000 to 2012 investigating the remission rates of orthopaedic implant infections after fracture repair and associated variables. RESULTS: A total of 139 episodes were included: There were 51 women (37%) and 28 immunosuppressed (20%) patients with a median age and American Society of Anaesthesiologists (ASA) score of 51 years and 2 points, respectively. The infected implants were plates (n = 75, 54 %), nails (24, 17%), wires (20), screws (10), cerclage cables or wires (3), hip screws (4) or material for spondylodesis (3). A pathogen was identified in 135 (97%) cases, including Staphylococcus aureus (73, 52%), coagulase-negative staphylococci (20), streptococci (7) and 19 Gram-negative rods. All patients underwent antibiotic treatment, and 128 (92%) remained in remission at a median follow-up time of 2.6 years (range one to 13 years). In multivariate logistic regression analysis, the plate infections were significantly associated with lower remission rates [65/75, 87%, odds ratio (OR) 0.1, 95% confidence interval (CI) 0.01-0.90]. No associations were found for gender, age, immune status, ASA score, additional surgical interventions (OR 0.4, 95% CI 0.1-4.1) or duration of antibiotic treatment (OR 1.0, 95% CI 0.98-1.01). CONCLUSIONS: Among all infected and removed orthopaedic implants, plates were associated with slightly lower remission rates, while the overall treatment success exceeded 90%. The duration of antibiotic therapy did not alter the outcome.

Failure modes in conservative and surgical management of infectious spondylodiscitis.

PURPOSE AND METHODS: We reviewed the management, failure modes, and outcomes of 196 patients treated for infectious spondylodiscitis between January 1, 2000 and December 31, 2010, at the Spinal Unit, Aarhus University Hospital, Aarhus, Denmark. Patients with infectious spondylodiscitis at the site of previous spinal instrumentation, spinal metastases, and tuberculous and fungal spondylodiscitis were excluded. RESULTS: Mean age at the time of treatment was 59 (range 1-89) years. The most frequently isolated microorganism was Staphylococcus aureus. The lumbosacral spine was affected in 64% of patients and the thoracic in 21%. In 24% of patients, there were neurologic compromise, four had the cauda equina syndrome and ten patients were paraplegic. Ninety-one patients were managed conservatively. Treatment failed in 12 cases, 7 patients required re-admission, 3 in-hospital deaths occurred, and 5 patients died during follow-up. Posterior debridement with pedicle screw instrumentation was performed in 75, without instrumentation in 19 cases. Seven patients underwent anterior debridement alone, and in 16 cases, anterior debridement was combined with pedicle screw instrumentation, one of which was a two-stage procedure. Re-operation took place in 12 patients during the same hospitalization and in a further 12 during follow-up. Two in-hospital deaths occurred, and five patients died during follow-up. Patients were followed for 1 year after treatment. Eight (9%) patients treated conservatively had a mild degree of back pain, and one (1%) patient presented with mild muscular weakness. Among surgically treated patients, 12 (10%) had only mild neurological impairment, one foot drop, one cauda equine dysfunction, but 4 were paraplegic. Twenty-seven (23%) complained of varying degrees of back pain. CONCLUSIONS: Conservative measures are safe and effective for carefully selected patients without spondylodiscitic complications. Failure of conservative therapy requires surgery that can guarantee thorough debridement, decompression, restoration of spinal alignment, and correction of instability. Surgeons should master various techniques to achieve adequate debridement, and pedicle screw instrumentation may safely be used if needed.

Absence of bactericidal effect of focused shock waves on an in-vitro biofilm model of an implant.

The objective of this study was to evaluate the bactericidal effect of shock waves (SWs) on gram-negative or gram-positive monocultured biofilms grown on an orthopedic implant in vitro. Cortical bone screws were individually cultured with Escherichia coli or Staphylococcus epidermidis to produce a biofilm. In each run of 8 screws, 6 screws were treated with shock waves and then sonicated to disrupt the biofilm. One screw was sonicated only and one was not shock waved or sonicated before sampling for plate count dilutions. Post-treatment serial dilutions and plate counts were done on an aliquot from the vial containing each screw to obtain the number of colony-forming units (CFUs). Shock waves were at a constant energy of 0.15 mJ/mm(2). Pulse number and screw orientation were varied. A linear mixed-effects model was used with "treatment" as a fixed effect and "run" as a random effect. Pairwise comparisons of treatments were performed with Tukey-Cramer's adjustment for P-values. Sonicated plate counts were greater than nonsonicated counts for each run. When all sonicated screws were compared to all nonsonicated screws, the counts were significantly increased (P = 0.0091). For each paired comparison between sonicated and shock wave treatment, the only significant difference was in the S. epidermidis biofilm treated at 2000 pulses in a horizontal position, which increased the post-treatment count (P = 0.0445). No bactericidal effects were seen on monocultured biofilms on cortical bone screws treated with shock waves.