Antibiotic prophylaxis in neurosurgery. Study comparing two groups of patients with and without treatment

Postoperative intracranial neurosurgery infection rates in North America versus Europe: a systematic analysis

BACKGROUND

Postoperative wound infection (PWI) after intracranial neurosurgery remains a significant worldwide problem, resulting in substantial morbidity/mortality if not combatted quickly and energetically. Although the danger of PWI is universally recognized, the reported incidence of PWI after intracranial neurosurgery remains variable, ranging from 1% to 8% in published series. The impact of geography on this reported variability has not been previously investigated. To address this issue, published comprehensive intracranial neurosurgery series were reviewed, segregating findings geographically between North American and European series.

METHODS

A comprehensive literature search was conducted using the Entrez gateway of the PubMed database. Studies conducted in North America and Europe reporting the incidence of PWI after intracranial neurosurgery were subjected to a thorough review. Data from studies meeting inclusion criteria (minimum of 500 cases with no systematic exclusion of procedures) were categorized by origin (North American/European) and design (retrospective/prospective). Recorded incidences were then compared using chi(2) analysis, and estimates of the relative risk of PWI were calculated.

RESULTS

Seven studies (4 North American, 3 European) met all of the inclusion criteria, with a 2.6-fold greater PWI incidence reported in the European studies (P < .001). The relative risk of PWI for Europeans versus North Americans per operative case was 2.60.

CONCLUSION

PWI after intracranial neurosurgery was nearly 3 times more likely in European versus North American studies. These findings should be considered by clinicians when estimating the risks of intracranial neurosurgery, and highlight the need for future prospective studies to provide evidence-based explanations for these differences.

Efficacy of Prophylactic Antibiotics Against Meningitis after Craniotomy: A Meta-Analysis

OBJECTIVE

Although prophylactic antibiotics have been shown by randomized clinical trials (RCTs) to help prevent deep infection after craniotomies, recent reports have suggested that antibiotics are not effective in preventing postcraniotomy meningitis.

METHODS

Data on meningitis as an end point from RCTs on prophylactic antibiotics for craniotomies were pooled in a random-effects meta-analysis.

RESULTS

Six prospective randomized trials or trial subgroups enrolling 1729 patients or operations were identified. Antibiotics reduced postoperative infection rates in five of the six RCTs; no trial individually showed a statistically significant benefit from antibiotics. The pooled odds ratio for meningitis with antibiotic treatment in the six RCTs was 0.43 (95% confidence interval, 0.20–0.92; P = 0.03). Subgroup analyses showed no detectable difference in antibiotic efficacy if antibiotics, with or without gram- negative coverage, were used or if the trial was single or double blinded. A sensitivity analysis showed modest dependence of the results of the analysis on the specific definition of postoperative meningitis used in interpreting trial results.

CONCLUSION

Prophylactic antibiotics administered before craniotomy reduce rates of postoperative meningitis by approximately one-half, a statistically and clinically significant benefit.

Efficacy of prophylactic antibiotic therapy in spinal surgery: a meta-analysis

OBJECTIVE

There is considerable variation in practice regarding the use of prophylactic antibiotic therapy in spinal operations. To date, individual studies have not demonstrated a significant benefit for prophylactic antibiotic therapy in spinal operations.

METHODS

Systematic database searches for randomized prospective trials of prophylactic antibiotic therapy in spinal surgery, general neurosurgery, and orthopedic surgery were performed. Random-effects meta-analysis and Bayesian meta-regressions of treatment benefits versus baseline infection rates and other trial characteristics were performed.

RESULTS

Six prospective randomized trials or trial subgroups, enrolling 843 patients, were identified, i.e., one spinal surgery trial, four general neurosurgery trials, and one general orthopedic surgery trial. No individual trial demonstrated a statistically significant effect of prophylactic antibiotic therapy for spinal surgery patients. Raw pooled infection rates were 2.2% (10 of 451 patients) with antibiotics and 5.9% (23 of 392 patients) without antibiotics. Individual trial infection rates ranged from 1.2 to 8.5%. The pooled odds ratio was 0.37 (95% confidence interval, 0.17-0.78), favoring antibiotic treatment (P < 0.01). There was no significant heterogeneity in treatment efficacy among the trials. Bayesian meta-regression was used to test whether antibiotics were less effective in trials with low baseline infection rates and whether an optimal antibiotic regimen could be identified. There was no significant difference in antibiotic treatment effects in trials with lower baseline infection rates, in trials using antibiotics with gram-negative coverage in addition to gram-positive coverage, or in trials using multiple-dose versus single-dose regimens. Nonrandomized studies of antibiotic therapy in spinal surgery yielded greater treatment effect estimates than did randomized trials, but not significantly so.

CONCLUSION

Prophylactic antibiotic therapy is beneficial for spinal surgery, even when expected infection rates without antibiotic treatment are low.

A randomized, double-blind comparison of ampicillin/sulbactam and ceftriaxone in the prevention of surgical-site infections after neurosurgery

BACKGROUND

The use of prophylactic antibiotics has been shown to decrease the rate of surgical-site infections after clean neurosurgical operations, although previous clinical trials have provided no evidence that one antibiotic is superior to another for this purpose.

OBJECTIVE

This study was undertaken to compare the rates of postoperative infectious complications of neurosurgery with prophylactic ceftriaxone and ampicillin/sulbactam, a less-expensive antibiotic.

METHODS

Consecutive patients undergoing neurosurgery between January and December 1998 were recruited for the study. Those who had an infectious disease for which antibiotics were required, who received antibiotics within 48 hours before surgery, were aged <12 or >85 years, had an indwelling catheter for the monitoring of intracranial pressure, or had a history of allergy to the study drugs were excluded. Before the operation, eligible patients were randomized to either ampicillin/sulbactam 3 g or ceftriaxone 2 g. Surgeons and patients were blinded to treatment assignment. The study drugs were administered by the anesthesiologist as an IV bolus after induction of general anesthesia. All patients were followed for 6 weeks postoperatively. If reoperation was required within 6 weeks of the original operation, the patient received the same antibiotic as during the first surgery, without further randomization.

RESULTS

Over the 1-year study period, 180 consecutive patients undergoing neurosurgical operations were recruited. Surgical-site infection occurred in 2 (2.3%) patients in the ampicillin/sulbactam group and 3 (3.3%) in the ceftriaxone group; nonsurgical-site infection occurred in 25 (28.4%) patients in the ampicillin/sulbactam group and 15 (16.3%) in the ceftriaxone group. The between-group differences were not statistically significant, with the exception of surgical implantation of foreign material, which was performed sig- nificantly more frequently in the ceftriaxone group (P = 0.045). In addition, 2 of 3 surgical-site infections in the ceftriaxone group involved foreign-material implantation; however, if these operations are omitted from the analysis, the difference between treatments remains nonsignificant.

CONCLUSIONS

The results suggest that ampicillin/sulbactam and ceftriaxone are of similar prophylactic efficacy in clean neurosurgical operations. Because the acquisition cost of 2 g ceftriaxone is approximately 3 times greater than that of 3 g ampicillin/sulbactam, the latter may be more cost-effective than the former for neurosurgical prophylaxis; however, other relevant hospital-related costs were not assessed in this study.

Prophylactic antibiotics with intracranial pressure monitors and external ventricular drains: a review of the evidence

BACKGROUND

The role of prophylactic antibiotics (PABs) in preventing infections associated with intracranial pressure (ICP) monitors and external ventricular drains (EVD) is not well defined.

METHODS

This study includes an analysis of published reports and a survey of current practices regarding the use of PABs with ICP monitors and EVDs. A computerized data search and a review of the abstracts from two major national neurosurgical meetings over the past decade yielded 85 related articles. Three independent investigators, blinded to the title, author(s), institution(s), results, and conclusions of the articles used predetermined inclusion criteria to select studies for meta-analysis. Thirty-six responses were returned from 98 questionnaires (37%) mailed to university neurosurgical programs.

RESULTS

Among the articles reviewed, only two studies met the predetermined inclusion criteria for the meta-analysis, and they were of insufficient size to produce statistically significant results. Among the 36 programs that responded to the survey, 26 (72%) used PABs, mainly cephalosporins (46%) and semisynthetic penicillins (38%), with ICP monitors and EVDs. Twenty-two (85%) used one drug, and 4 (15%) used two drugs. Twenty-two (61%) of the total group reported intra-institutional variation in practices among individual staff neurosurgeons. Nineteen (53%) expressed interest in a retrospective study, and 27 (75%) expressed interest in a prospective study on the role of PABs in minor neurosurgical procedures.

CONCLUSION

No consensus regarding the use of PABs with ICP monitors and EVDs is noted. Randomized controlled trials of sufficiently large size with appropriate blinding are needed to address this issue.

Antibiotic prophylaxis in cerebrospinal fluid shunting: a prospective randomized trial in 129 patients

The efficacy of a single dose of cefotiam, a cephalosporin of the second generation, as prophylaxis for postoperative infection was analyzed in a prospective randomized study of 129 patients undergoing cerebrospinal fluid shunting. The main focus of interest was the rate of shunt infection requiring operative shunt removal. Data were evaluated in the total group and subgroups formed for normal and high risk patients, respectively. The overall rate of shunt infection was 7.5% in the cefotiam group and 12.9% in the control group. In the high risk subgroup infection rate was 14.3% with and 26.3% without cefotiam as opposed to 4.3% and 6.9%, respectively, in the normal risk subgroup. Although our results do not reach statistical significance, there is a noticeable difference of infection rate between those patients who receive the antibiotic and those who do not. Therefore, we favor single dose antibiotic prophylaxis in shunting procedures.

Ceftizoxime versus vancomycin and gentamicin in neurosurgical prophylaxis: a randomized, prospective, blinded clinical study

In a prospective, randomized, blinded study, 826 patients undergoing clean neurosurgical procedures received single intravenous doses of ceftizoxime (2 g) (n = 422) or a combination of vancomycin (1 g) and gentamicin (80 mg) (n = 404) 1 hour before an incision was made. Patients with infected or contaminated wounds and those receiving shunts or other implants were excluded. Primary wound infections occurred within 30 days in five patients in each group and were most common after spinal surgery and procedures through previous incisions. Secondary infections (pneumonias, urinary tract infections, and intravenous line-related bacteremia) occurred in 24 patients in the ceftizoxime group and 25 in the vancomycin/gentamicin group. The infection rates after transsphenoidal procedures (n = 129) were remarkably low in both groups. Ceftizoxime caused no adverse drug reactions, but six patients in the vancomycin/gentamicin group had clinically significant infusion-related hypotension or flushing. Placement of a temporary external drain, use of an operating microscope, preoperative steroids, and diabetes were not associated with increased infection rates. Analysis of routinely encountered ventricular cerebrospinal fluid and simultaneously obtained peripheral blood showed low but detectable levels of all three antibiotics within 2 hours; only ceftizoxime, however, achieved cerebrospinal fluid levels sufficient to inhibit the staphylococcus and Gram-negative bacilli most often associated with postneurosurgical infections. We conclude that ceftizoxime is as effective as vancomycin and gentamicin in neurosurgical prophylaxis but is less toxic and penetrates cerebrospinal fluid better.