Vertebral osteomyelitis after spine instrumentation surgery: risk factors and management.

BACKGROUND: Vertebral osteomyelitis after spine instrumentation surgery (pVOM) is a rare complication. Most cases of infection occur early after surgery that involve skin and soft tissue and can be managed with debridement, antibiotics, and implant retention (DAIR). AIM: To identify pVOM risk factors and evaluate management strategies. METHODS: From a multicentre cohort of deep infection after spine instrumentation (IASI) cases (2010-2016), pVOM cases were compared with those without vertebral involvement. Early and late infections were defined (<60 days and >60 days after surgery, respectively). Multivariate analysis was used to explore risk factors. FINDINGS: Among 410 IASI cases, 19 (4.6%) presented with pVOM, ranging from 2% (7/347) in early to 19.1% (12/63) in late IASIs. After multivariate analysis, age (adjusted odds ratio (aOR): 1.10; 95% confidence interval (CI): 1.03-1.18), interbody fusion (aOR: 6.96; 95% CI: 2-24.18) and coagulase-negative staphylococci (CoNS) infection (aOR: 3.83; 95% CI: 1.01-14.53) remained independent risk factors for pVOM. Cases with pVOM had worse prognoses than those without (failure rate; 26.3% vs 10.8%; P = 0.038). Material removal was the preferred strategy (57.9%), mainly in early cases, without better outcomes (failure rate; 33.3% vs 50% compared with DAIR). Late cases managed with removal had greater success compared with DAIR (failure rate; 0% vs 40%; P = 0.067). CONCLUSION: Risk factors for pVOM are old age, use of interbody fusion devices and CoNS aetiology. Although the diagnosis leads to a worse prognosis, material withdrawn should be reserved for late cases or when spinal fusion is achieved.

Necrotizing fasciitis in haematological patients: a different scenario.

To describe and compare the characteristics of necrotizing fasciitis (NF) in patients with and without haematological malignancy. All adult patients diagnosed with NF and treated at our hospital were included (January 2010-March 2019). Diagnosis was based on intraoperative findings or consistent clinical/radiological characteristics, and patients were classified as group A (with haematological malignancy) or group B (without haematological malignancy). Student's t (quantitative), Fisher's exact (qualitative), and Kaplan-Meyer tests were used for the statistical analysis. The study included 29 patients: 8 in group A and 21 in group B. All haematological patients had severe neutropenia (0.2 [0.02-0.5] ×109 cells/L; p < 0.001) and positive blood cultures (100% vs. 61.9%; p = 0.04) at diagnosis. Gram-negative bacilli NF was more common in group A (87.5% vs. 9.5%; p = 0.001), predominantly due to Escherichia coli (50% vs. 9.5%; p = 0.056). Surgical treatment was less common in haematological patients (5 [62.5%] vs. 21 [100%]; p = 0.015). Overall, 9 (31%) patients died: 4 (50%) in group A and 5 (23.8%) in group B (p = 0.17). The univariate analysis showed that mortality tended to be higher (OR 3.2; 95%CI 0.57-17.7; p = 0.17) and to occur earlier (2.2 ± 2.6 vs. 14.2 ± 19.9 days; p = 0.13) in haematological patients. The LRINEC index > 6 did not predict mortality in either group. In our study, NF in patients with haematological malignancies was mainly due to Gram-negative bacilli, associated to high and early mortality rates. In our experience, the LRINEC scale was not useful for predicting mortality.

The changing epidemiology of spinal tuberculosis: the influence of international immigration in Catalonia, 1993-2014.

The overall incidence of spinal tuberculosis (TB) appears to be stable or declining in most European countries, but with an increasing proportion of cases in the foreign-born populations. We performed a retrospective observational study (1993-2014), including all cases of spinal TB diagnosed at a Barcelona hospital to assess the epidemiological changes. Fifty-four episodes (48·1% males, median age 52 years) of spinal TB were diagnosed. The percentage of foreign-born residents with spinal TB increased from 14% to 45·2% in the last 10 years (P = 0·017). Positive Mycobacterium tuberculosis testing in vertebral specimens was 88·2% (15/17) for GeneXpert MTB/RIF. Compared with natives, foreign-born patients were younger (P < 0·01) and required surgery more often (P = 0·003) because of higher percentages of paravertebral abscess (P = 0·038), cord compression (P = 0·05), and persistent neurological sequelae (P = 0·05). In our setting, one-third of spinal TB cases occurred in non-native residents. Compared with natives, foreign-born patients were younger and had greater severity of the disease. The GeneXpert MTB/RIF test may be of value for diagnosing spinal TB.

Gram-negative prosthetic joint infection: outcome of a debridement, antibiotics and implant retention approach. A large multicentre study.

We aim to evaluate the epidemiology and outcome of gram-negative prosthetic joint infection (GN-PJI) treated with debridement, antibiotics and implant retention (DAIR), identify factors predictive of failure, and determine the impact of ciprofloxacin use on prognosis. We performed a retrospective, multicentre, observational study of GN-PJI diagnosed from 2003 through to 2010 in 16 Spanish hospitals. We define failure as persistence or reappearance of the inflammatory joint signs during follow-up, leading to unplanned surgery or repeat debridement>30 days from the index surgery related death, or suppressive antimicrobial therapy. Parameters predicting failure were analysed with a Cox regression model. A total of 242 patients (33% men; median age 76 years, interquartile range (IQR) 68-81) with 242 episodes of GN-PJI were studied. The implants included 150 (62%) hip, 85 (35%) knee, five (2%) shoulder and two (1%) elbow prostheses. There were 189 (78%) acute infections. Causative microorganisms were Enterobacteriaceae in 78%, Pseudomonas spp. in 20%, and other gram-negative bacilli in 2%. Overall, 19% of isolates were ciprofloxacin resistant. DAIR was used in 174 (72%) cases, with an overall success rate of 68%, which increased to 79% after a median of 25 months' follow-up in ciprofloxacin-susceptible GN-PJIs treated with ciprofloxacin. Ciprofloxacin treatment exhibited an independent protective effect (adjusted hazard ratio (aHR) 0.23; 95% CI, 0.13-0.40; p<0.001), whereas chronic renal impairment predicted failure (aHR, 2.56; 95% CI, 1.14-5.77; p 0.0232). Our results confirm a 79% success rate in ciprofloxacin-susceptible GN-PJI treated with debridement, ciprofloxacin and implant retention. New therapeutic strategies are needed for ciprofloxacin-resistant PJI.

Postoperative urinary tract infection and surgical site infection in instrumented spinal surgery: is there a link?

A potential relationship between postoperative urinary tract infection (UTI) and surgical site infection (SSI) following posterior spinal fusion and instrumentation (PSFI) was investigated. A retrospective review was performed of prospectively collected demographic, clinical and microbiological data of 466 consecutive patients (median age, 53.7 years (interquartile range (IQR) 33.8-65.6); 58.6% women) undergoing PSFI to identify those with UTI in the first 4 weeks and SSI in the first 12 weeks after PSFI. Overall, 40.8% had an American Society of Anesthesiologists score of >2, and 49.8% had undergone fusion of more than three segments. Eighty-nine patients had UTI, 54 had SSI, and 22 had both conditions. In nine of the 22 (38%) cases, the two infections were caused by the same microorganism. The urinary tract was the probable source of SSI by Gram-negative bacteria in 38% (8/21) of cases. On multivariate analysis, UTI (OR 3.1, 95% CI 1.6-6.1; P 0.001) and instrumentation of more than three segments (OR 2.7, 95% CI 1.1-6.3; P 0.024) were statistically associated with SSI. Patients receiving ciprofloxacin for UTI had higher microbial resistance rates to fluoroquinolones at SSIs (46.13%) than those without ciprofloxacin (21.9%), although the difference did not reach statistical significance (p 0.1). In our series, UTI was significantly associated with SSI after PSFI. On the basis of our results, we conclude that further efforts to reduce the incidence of postoperative UTI and provide adequate empirical antibiotic therapy that avoids quinolones whenever possible may help to reduce SSI rates and potential microbial resistance.

Implant survival after deep infection of an instrumented spinal fusion.

This study evaluates the long-term survival of spinal implants after surgical site infection (SSI) and the risk factors associated with treatment failure. A Kaplan-Meier survival analysis was carried out on 43 patients who had undergone a posterior spinal fusion with instrumentation between January 2006 and December 2008, and who consecutively developed an acute deep surgical site infection. All were appropriately treated by surgical debridement with a tailored antibiotic program based on culture results for a minimum of eight weeks. A 'terminal event' or failure of treatment was defined as implant removal or death related to the SSI. The mean follow-up was 26 months (1.03 to 50.9). A total of ten patients (23.3%) had a terminal event. The rate of survival after the first debridement was 90.7% (95% confidence interval (CI) 82.95 to 98.24) at six months, 85.4% (95% CI 74.64 to 96.18) at one year, and 73.2% (95% CI 58.70 to 87.78) at two, three and four years. Four of nine patients required re-instrumentation after implant removal, and two of the four had a recurrent infection at the surgical site. There was one recurrence after implant removal without re-instrumentation. Multivariate analysis revealed a significant risk of treatment failure in patients who developed sepsis (hazard ratio (HR) 12.5 (95% confidence interval (CI) 2.6 to 59.9); p < 0.001) or who had > three fused segments (HR 4.5 (95% CI 1.25 to 24.05); p = 0.03). Implant survival is seriously compromised even after properly treated surgical site infection, but progressively decreases over the first 24 months.

Individualized antibiotic prophylaxis reduces surgical site infections by gram-negative bacteria in instrumented spinal surgery.

PURPOSE: Surgical site infection (SSI) can be a challenging complication after posterior spinal fusion and instrumentation (PSFI). An increasing rate of SSI by gram-negative bacteria (GNB) has been observed. Current guideline recommendations have not been effective for preventing infection by these microorganisms. METHODS: Retrospective cohort study comparing two consecutive groups of patients undergoing PSFI at a single institution. Cohort A includes 236 patients, operated between January 2006 and March 2007, receiving standard preoperative antibiotic prophylaxis with cefazolin (clindamycin in allergic patients). Cohort B includes 223 patients operated between January and December 2009, receiving individualized antibiotic prophylaxis and treatment based on preoperative urine culture. Cultures were done 3-5 days before surgery in patients meeting one of the following risk criteria for urinary tract colonization: hospitalization longer than 7 days, indwelling catheter, neurogenic bladder, history of urinary incontinence, or history of recurrent urinary tract infection. RESULTS: Twenty-two (9.3%) patients in cohort A developed SSI, 68.2% due to GNB. 38 (17%) patients in cohort B were considered at risk for GNB colonization; preoperative urine culture was positive in 14 (36%). After adjusted antibiotic prophylaxis, 15 (6.27%) patients in cohort B developed SSI, 33.4% due to GNB. A statistically significant reduction in GNB SSI was seen in cohort B (Fisher's exact test, p = 0.039). CONCLUSION: Higher preoperative GNB colonization rates were found in patients with neurogenic bladder or indwelling catheters. Preoperative bacteriological screening, treatment for bacteriuria, and individualized antibiotic prophylaxis were effective for reducing GNB SSI.