The outcome following spinal instrumentation in haemodialyzed patients with pyogenic spondylodiscitis

Are Dental Procedures Associated With Pyogenic Vertebral Osteomyelitis?

BACKGROUND

Dental procedures can lead to bacteremia and have been considered a potential risk factor for pyogenic vertebral osteomyelitis (PVO). However, data on the association between dental procedures and PVO are limited.

QUESTIONS/PURPOSES

(1) After controlling for relevant confounding variables, are dental procedures associated with an increased risk of PVO? (2) Does antibiotic prophylaxis before dental procedures effectively decrease the risk of PVO?

METHODS

A case-crossover study was conducted to investigate the association between dental procedures and PVO using a Japanese claims database. The advantage of this study design is that confounding factors that do not vary over time are automatically adjusted for, because cases act as their own controls. From April 2014 to September 2021, the database included 8414 patients who were hospitalized for PVO. Of these, 50% (4182 of 8414) were excluded because they had not undergone any dental procedures before the index date, a further 0.1% (10 of 8414) were excluded because they were younger than 18 years at the index date, and a further 7% (623 of 8414) were excluded because they did not have at least 20 weeks of continuous enrollment before the index date, leaving 43% (3599 of 8414) eligible for analysis here. The mean age was 77 ± 11 years, and 55% (1985 of 3599) were men. Sixty-five percent (2356 of 3599) of patients had a diagnosis of diabetes mellitus, and 42% (1519 of 3599) of patients had a diagnosis of osteoporosis. We compared the frequency of dental procedures between a 4-week hazard period before the admission date for PVO and two control periods, 9 to 12 weeks and 17 to 20 weeks before the admission date for PVO, within individuals. We calculated odds ratios and 95% confidence intervals using conditional logistic regression analysis.

RESULTS

Comparing the hazard and matched control periods within individuals demonstrated that dental procedures were not associated with an increased risk of PVO (OR 0.81 [95% CI 0.72 to 0.92]; p < 0.001). Additional analysis stratified by antibiotic prophylaxis use showed that antibiotic prophylaxis was not associated with a lower OR of developing PVO after dental procedures (with antibiotic prophylaxis: OR 1.11 [95% CI 0.93 to 1.32]; p < 0.26, without antibiotic prophylaxis: OR 0.72 [95% CI 0.63 to 0.83]; p < 0.001). Our sensitivity analyses, in which the exposure assessment interval was extended from 4 to 8 or 12 weeks and exposure was stratified by whether the dental procedure was invasive, demonstrated results that were consistent with our main analysis.

CONCLUSION

Dental procedures were not associated with an increased risk of subsequent PVO in this case-crossover study. The effectiveness of antibiotic prophylaxis was not demonstrated in the additional analysis that categorized exposure according to the use of antibiotic prophylaxis. Our results suggest that the association between dental procedures and PVO may have been overestimated. Maintaining good oral hygiene may be important in preventing the development of PVO. The indications for antibiotic prophylaxis before dental procedures should be reconsidered in view of the potential risk of adverse drug reactions to antibiotic prophylaxis and the emergence of drug-resistant pathogens. Larger randomized controlled trials are needed to confirm these findings and assess the role of antibiotic prophylaxis.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Recurrence rate after posterior percutaneous screw fixation without anterior debridement for pyogenic spondylitis compared with conservative treatment: a propensity score-matched analysis

PURPOSE

Previous studies have shown that percutaneous pedicle screw (PPS) posterior fixation without anterior debridement for pyogenic spondylitis can improve patient quality of life compared with conservative treatment. However, data on the risk of recurrence after PPS posterior fixation compared with conservative treatment is lacking. The aim of this study was to compare the recurrence rate of pyogenic spondylitis after PPS posterior fixation without anterior debridement and conservative treatment.

METHODS

The study was conducted under a retrospective cohort design in patients hospitalized for pyogenic spondylitis between January 2016 and December 2020 at 10 affiliated institutions. We used propensity score matching to adjust for confounding factors, including patient demographics, radiographic findings, and isolated microorganisms. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for recurrence of pyogenic spondylitis during the follow-up period in the matched cohort.

RESULTS

148 patients (41 in the PPS group and 107 in the conservative group) were included. After propensity score matching, 37 patients were retained in each group. PPS posterior fixation without anterior debridement was not associated with an increased risk of recurrence compared with conservative treatment with orthosis (HR, 0.80; 95% CI, 0.18-3.59; P = 0.77).

CONCLUSIONS

In this multi-center retrospective cohort study of adults hospitalized for pyogenic spondylitis, we found no association in the incidence of recurrence between PPS posterior fixation without anterior debridement and conservative treatment.

The epidemiology of concurrent infection in patients with pyogenic spine infection and its association with early mortality: A nationwide cohort study based on 10,695 patients

BACKGROUND

Generally, a sufficient duration of relevant antibiotics based on an appropriate culture combined with proper surgical treatment guarantees a favorable clinical outcome in patients with pyogenic spine infections. However, a patient's condition often deteriorates as concurrent infections occur in other organs, leading to mortality. Therefore, this study aimed to investigate the epidemiology of concurrent infections in patients with a pyogenic spine infection and estimate the rates and risks of early mortality.

METHODS

Patients with a pyogenic spine infection were identified using a national claims database that includes the entire population. The epidemiology of the six types of concurrent infections was investigated, and the corresponding early mortality rates and risks were estimated. The results were validated internally by bootstrapping and externally by defining two additional cohorts for sensitivity analysis.

RESULTS

Among 10,695 patients with a pyogenic spine infection, the prevalence of the six types of concurrent infections was 11.3 % for urinary tract infections, 9.4 % for intra-abdominal infections, 8.5 % for pneumonia, 4.6 % for septic arthritis or osteomyelitis of the extremities, 0.7 % for central nervous system infections, and 0.5 % for cardiac infections. Patients with a concurrent infection had approximately 4-fold greater mortality than those without (3.3 % vs. 0.8 %). The early mortality rates were particularly higher in patients with multiple or specific types of concurrent infections, including central nervous system infections, cardiac infections, and pneumonia. In addition, the mortality trends differed significantly according to the number and type of concurrent infections.

CONCLUSIONS

These data on six types of concurrent infection among patients with pyogenic spinal infection can be used as a source of reference by clinicians.

Infective spondylodiscitis in hemodialysis patients

Background

Spondylodiscitis is a potentially catastrophic complication in patients on hemodialysis. It is slow and insidious onset and nonspecific symptoms have contributed to the late detection of this infectious process. Here, we reviewed the clinical characteristics and outcomes for patients on hemodialysis who developed spondylodiscitis who were diagnosed with spondylodiscitis.

Methods

From 2011 to 2021, 11 (0.4%) of 2557 patients on hemodialysis were diagnosed with spondylodiscitis based on clinical symptoms, patients averaged 56.9 years of age, seven were male, and they presented with fever in just two cases. The most frequent comorbidities included hypertension (ten patients) and diabetes mellitus (seven patients). Here, we reviewed the clinical, radiological (i.e., MR scans), laboratory markers, and treatment choices (i.e., nonsurgical vs. surgical) for these 11 hemodialysis patients.

Results

Ten of the 11 patients underwent spinal surgery, and five were later readmitted for recurrent of infections. There was just one nonsurgical mortality.

Conclusion

For patients on hemodialysis, the new-onset of spinal pain may signal the onset of spondylodiscitis which should be rapidly diagnosed with MR studies and managed in a timely fashion either with antibiotic therapy and/or with surgery/antibiotics.

Recurrence Rates and Its Associated Factors after Early Spinal Instrumentation for Pyogenic Spondylodiscitis: A Nationwide Cohort Study of 2148 Patients

Recent studies have consistently reported the safety and effectiveness of early spinal instrumentation for pyogenic spondylodiscitis. However, none of these studies investigated the recurrence rate or associated factors based on this specific group of patients. Recurrence prediction models that are not based on a homogenous cohort of patients undergoing early spinal instrumentation show theoretical limitations for clinical use. A nationwide, population-based, retrospective cohort study using a claims database was planned to investigate the recurrence rate and its associated factors in patients who underwent early instrumented spinal fusion surgery for pyogenic spondylodiscitis. We used data from the Korean National Health Insurance claims database collected between 2014 and 2018. A total of 2148 patients who underwent early (within 6 weeks after the diagnosis) instrumented spinal fusion surgery for pyogenic spondylodiscitis were included, including 1925 patients (90%) without recurrence and 223 patients (10%) with recurrence. Logistic regression models were used to identify factors associated with recurrence, and sensitivity analysis was performed according to two different definitions for recurrence: shorter (2 weeks or more) and longer (6 weeks or more) periods of antibiotic therapy for recurrence. The recurrence rates in our cohort were 14.1%, 10.4%, and 8.0% at 2, 4, and 6 weeks, respectively, in relation to the duration of antibiotic treatment for recurrence. We identified age 60−69 years (OR = 2.42), age > 70 years (OR = 2.29), posterior thoracic approach (OR = 1.85), multiple surgical approaches (OR = 4.17), use of a cage (OR = 1.66), transfusion (OR = 2.55), antibiotics for resistant organisms (OR = 2.55), and systemic steroid treatment over 2 weeks (OR = 2.27) as the factors associated with recurrence. The recurrence rates and associated factors from our first population-based and the largest clinical study can be practically used as a reasonable reference and provide clinicians with an acceptable tool for the comprehensive risk assessment for recurrence after early spinal instrumentation for pyogenic spondylodiscitis.

Clinical Characteristics of Patients with Pyogenic Vertebral Osteomyelitis and Concurrent Infections and Their Clinical Outcomes

Patients with pyogenic vertebral osteomyelitis (PVO) often develop concurrent infections, and a significant number of these patients show rapid deterioration in their medical condition, leading to mortality without PVO-related structural instability or neurological deficits. To improve clinical outcomes, we investigated the clinical presentation and treatment outcomes of patients with PVO and concurrent infections. This study included 695 patients with PVO, of which 175 (25%) had concurrent infections and 520 (75%) did not. The clinical characteristics of the two groups were compared, and multivariable analysis was performed to identify the association between concurrent infections and clinical outcomes. Patients with concurrent infections were older and had more comorbidities than those without. Moreover, there were significant intergroup differences in the anatomical involvement of PVO, and patients with concurrent infections had a higher number of regions involved more frequently than those without concurrent infections (15% vs. 6%). In contrast, patients with concurrent infections showed a lower degree of focal invasiveness, including a lower incidence of posterior abscess (47% vs. 59%; p = 0.008) and fewer neurological impairments according to the American Spinal Injury Association grade (p < 0.001) than those without concurrent infections. The causative organisms also differed significantly between the two groups, and patients with concurrent infections had a greater proportion of Gram-negative infections (31% vs. 16%, respectively) and a smaller proportion of methicillin-resistant S. aureus infections than those without concurrent infections (6% vs. 24%). Consequently, their clinical outcomes were significantly different, and patients with concurrent infections showed lower recurrence and higher mortality rates. We investigated the 1-year recurrence and mortality rates and their 95% confidence intervals according to the types of concurrent infections and their time of diagnosis and found variations in these parameters. Our results, based on a large number of patients, can be practically used as a reasonable reference to warn clinicians of the clinical risks of concurrent infections in patients with PVO and to help predict their clinical outcomes.

Treatment Guideline for Patients with Native Culture-negative Pyogenic Vertebral Osteomyelitis

BACKGROUND

With the development of evidence-based guidelines for the diagnosis and antibiotic treatment of patients with pyogenic vertebral osteomyelitis, various nonsurgical and surgical treatment strategies have achieved favorable results. However, sufficient administration of appropriate antibiotics is a prerequisite for treatment success, which cannot be guaranteed in patients with culture-negative pyogenic vertebral osteomyelitis. Unfortunately, previous studies on culture-negative pyogenic vertebral osteomyelitis were limited by small patient groups, short follow-up periods, varied treatment protocols, and inconsistently defined clinical endpoints.

QUESTIONS/PURPOSES

Among patients treated according to our center's treatment protocol for culture-negative pyogenic vertebral osteomyelitis, which included patients treated without surgery, with surgery but without spinal instrumentation, as well as patients treated with instrumented surgery, (1) what proportion of patients in each treatment group experienced recurrence (or persistence) of infection, complications of treatment, and death; and (2) what factors were independently associated with recurrent or persistent infection after treatment under this algorithm?

METHODS

This was a retrospective evaluation of a treatment protocol in use at one center from 2008 to 2020. During that time, we treated 183 patients for culture-negative pyogenic vertebral osteomyelitis. The diagnosis was based on clinical, laboratory, and radiological features excluding disease that presents similar features to pyogenic vertebral osteomyelitis. For those patients, our protocol included three possible approaches: nonsurgical treatment, including the use of empirical antibiotics (nonoperative group, n = 82); spinal decompression without instrumentation (noninstrumented group, n = 41); and spinal decompression with instrumentation (instrumented group, n = 60). The indications for each treatment during the period remained relatively consistent. Nonsurgical treatment including empirical antibiotics was applied to all patients according to the specified antibiotic protocol. Spinal decompression without instrumentation was employed when a patient presented substantial or aggravating neurologic deficits or intractable pain from an abscess. Instrumentation was added in patients with mechanical instability before or after spinal decompression. Minimum follow-up to be included in this study was 1 year, and 91% (252 of 277) of patients were accounted for at that time, with no differential loss to follow-up among the study groups (12, five, and four patients missing from the three groups, respectively, at 1 year). Chart review was performed to ascertain the proportion of patients in each group who experienced recurrence, complications, and death. Factors associated with recurrence were assessed across the entire cohort using a multivariable logistic model. We analyzed 1-year recurrence and mortality rates using the Kaplan-Meier method, and their 95% confidence intervals were calculated using the method by Hosmer and Lemeshow.

RESULTS

At 1 year, the recurrence-free survival rate was 87% (95% confidence interval 78% to 93%) in the nonoperative group, 87% (95% CI 72% to 94%) in the noninstrumented group, and 91% (95% CI 80% to 96%) in the instrumented group. The proportion of patients who experienced a major medical complication in each group was 12% (10 of 82), 10% (4 of 41), and 8% (5 of 60), respectively. At 1 year, the survival rate with patient death as the endpoint was 95% (95% CI 88% to 98%) in the nonoperative group, 95% (95% CI 82% to 99%) in the noninstrumented group, and 97% (95% CI 87% to 99%) in the instrumented group. After controlling for potentially confounding variables including age, medical comorbidities, and anatomical involvement of infection, the following factors were independently associated with increased odds of infection recurrence or persistence: higher Charlson Comorbidity Index (CCI) score (odds ratio 1.6 per point on the CCI [95% CI 1.2 to 2.1]; p = 0.004) and the presence of a psoas abscess (OR 4.7 [95% CI 1.6 to 13.9]; p = 0.005).

CONCLUSION

Among patients with negative initial nonoperative culture results, spinal decompression and abscess drainage can be used in those with substantial or aggravating neurological deficits or intractable pain caused by an abscess, while additional early spinal instrumentation can be applied upon consideration of their medical comorbidities and the presence of a psoas abscess when mechanical instability is present before or after the spinal decompression. Reasonable clinical results can be expected, regardless of the results from subsequent operative cultures. However, our study results should be replicated by other centers, and further studies that consider individual differences such as bone mineral density and include patients with previous spinal instrumentation or recurrent infection should be performed to establish a more comprehensive treatment protocol.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Clinical Outcomes in Older Patients Aged over 75 Years Who Underwent Early Surgical Treatment for Pyogenic Vertebral Osteomyelitis

Older patients with pyogenic vertebral osteomyelitis (PVO) usually have more medical comorbidities compared with younger patients, and present with advanced infections from different causative organisms. To aid surgical decision-making, we compared surgical outcomes of older patients with PVO to those who underwent nonoperative treatment. We identified the risk factors for adverse post-operative outcomes, and analyzed the clinical risks from further spinal instrumentation. This retrospective comparative study included 439 patients aged ≥75 years with PVO. Multivariable analysis was performed to compare treatment outcomes among three groups: 194, 130, and 115 patients in the non-operative, non-instrumented, and instrumented groups, respectively. The risk factors for adverse outcomes after surgical treatment were evaluated using a logistic regression model, and the estimates of the multivariable models were internally validated using bootstrap samples. Recurrence and mortality of these patients were closely associated with neurologic deficits, and increased surgical invasiveness, resulting from additional spinal instrumentation, did not increase the risk of recurrence or mortality. We propose that surgical treatment for these patients should focus on improving neurologic deficits through immediate and sufficient removal of abscesses. Spinal instrumentation can be performed if indicated, within reasonable clinical risk.

Prediction of Recurrence in Pyogenic Vertebral Osteomyelitis by Artificial Neural Network Using Time-series Data of C-Reactive Protein: A Retrospective Cohort Study of 704 Patients

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The aim of this study was to develop recurrence-prediction models of pyogenic vertebral osteomyelitis (PVO).

SUMMARY OF BACKGROUND DATA

Prediction of recurrence in PVO is crucial to avoid additional prolonged antibiotic therapy and aggressive spinal surgery and to reduce mortality. However, prediction of PVO recurrence by previously identified, initial risk factors is limited in PVO patients who exceptionally require prolonged antibiotic therapy and experience various clinical events during the treatment. We hypothesized that time-series analysis of sequential C-reactive protein (CRP) routinely measured to estimate the response to the antibiotics in PVO patients could reflect such long treatment process and increase the power of the recurrence-prediction model.

METHODS

A retrospective study was performed to develop a PVO recurrence-prediction model, including initial risk factors and time-series data of CRP. Of 704 PVO patients, 493 and 211 were divided into training and test cohorts, respectively. Conventional stepwise logistic regression and artificial neural network (ANN) models were created from the training cohort, and the predictions of recurrence in the test cohort were compared.

RESULTS

Prediction models using initial risk factors showed poor sensitivity (4.7%) in both conventional logistic model and ANN models. However, baseline ANN models using time-series CRP data showed remarkably increased sensitivity (55.8%-60.5%). Ensemble ANN model using both initial risk factors and time-series CRP data showed additional benefit in prediction power.

CONCLUSION

The recurrence-prediction models for PVO created only using the initial risk factors showed low sensitivity, regardless of statistical method. However, ANN models using time-series data of CRP values and their ensemble model showed considerably increased prediction power. Therefore, clinicians treating PVO patients should pay attention to the treatment response including changes of CRP levels to identify high-risk patients for recurrence, and further studies to develop recurrence-prediction model for PVO should focus on the treatment response rather than initial risk factors.Level of Evidence: 4.

Risk factor analysis of surgery-related complications in primary cervical spine surgery for degenerative diseases using a surgeon-maintained database

AIMS

This study, using a surgeon-maintained database, aimed to explore the risk factors for surgery-related complications in patients undergoing primary cervical spine surgery for degenerative diseases.

METHODS

We studied 5,015 patients with degenerative cervical diseases who underwent primary cervical spine surgery from 2012 to 2018. We investigated the effects of diseases, surgical procedures, and patient demographics on surgery-related complications. As subcategories, the presence of cervical kyphosis ≥ 10°, the presence of ossification of the posterior longitudinal ligament (OPLL) with a canal-occupying ratio ≥ 50%, and foraminotomy were selected. The surgery-related complications examined were postoperative upper limb palsy (ULP) with a manual muscle test (MMT) grade of 0 to 2 or a reduction of two grade or more in the MMT, neurological deficit except ULP, dural tear, dural leakage, surgical-site infection (SSI), and postoperative haematoma. Multivariate logistic regression analysis was performed.

RESULTS

The significant risk factors (p < 0.050) for ULP were OPLL (odds ratio (OR) 1.88, 95% confidence interval (CI) 1.29 to 2.75), foraminotomy (OR 5.38, 95% CI 3.28 to 8.82), old age (per ten years, OR 1.18, 95% CI 1.03 to 1.36), anterior spinal fusion (OR 2.85, 95% CI 1.53 to 5.34), and the number of operated levels (OR 1.25, 95% CI 1.11 to 1.40). OPLL was also a risk factor for neurological deficit except ULP (OR 5.84, 95% CI 2.80 to 12.8), dural tear (OR 1.94, 95% CI 1.11 to 3.39), and dural leakage (OR 3.15, 95% CI 1.48 to 6.68). Among OPLL patients, dural tear and dural leakage were frequently observed in those with a canal-occupying ratio ≥ 50%. Cervical rheumatoid arthritis (RA) was a risk factor for SSI (OR 10.1, 95% CI 2.66 to 38.4).

CONCLUSION

The high risk of ULP, neurological deficit except ULP, dural tear, and dural leak should be acknowledged by clinicians and OPLL patients, especially in those patients with a canal-occupying ratio ≥ 50%. Foraminotomy and RA were dominant risk factors for ULP and SSI, respectively. An awareness of these risks may help surgeons to avoid surgery-related complications in these conditions. Cite this article: Bone Joint J 2021;103-B(1):157-163.

Treatment outcomes in patients with pyogenic vertebral osteomyelitis who have cirrhosis

Early diagnosis and proper treatment of pyogenic vertebral osteomyelitis (PVO) in patients with cirrhosis is challenging to clinicians, and the mortality rate is expected to be high. A retrospective study was conducted to investigate the treatment outcome in PVO patients with cirrhosis and to identify the predictors of their mortality. Mortality was divided into two categories, 30-day and 90-day mortality. A stepwise multivariate logistic regression model was used to identify predictors of mortality. Eighty-five patients were identified after initial exclusion. The patients’ mean age was 60.5 years, and 50 patients were male. The early mortality rates within 30 and 90 days were 17.6% and 36.5%, respectively. Multivariate analysis revealed that increased age, CTP class C, and bacteremia at the time of PVO diagnosis were predictors of 30-day mortality, while higher MELD score, presence of combined infection, and multiple spinal lesions were predictors of 90-day mortality. Attention should be paid to the high mortality between 30 and 90 days after PVO diagnosis (18.8%), which was higher than the 30-day mortality. Liver function was consistently a strong predictor of mortality in PVO patients with cirrhosis. The high-risk patients should be targeted for an aggressive diagnostic approach, using spinal MRI and intensive monitoring and treatment strategies.