Hospital Santa Casa de Misericórdia de Vitória, Vitória, ES, Brazil
Introduction
Low back pain with or without sciatica affects approximately 80% ofthe world population. Spinal instability, with or without disc disease, is an important etiology of this disease.
In cases of low back pain refractory to conservative treatment, and after careful and accurate diagnosis of vertebral instability, lumbar arthrodesis (which consists of spinal fusion) is indicated.
Although lumbar arthrodesis is a good method for pain relief, it also presents complications; one of the most important is surgical site infection (SSI). Although its incidence is low, its effects are devastating. SSI can lead to economic loss and injury to patients due to several factors, including the need for prolonged use of antimicrobial drugs and secondary surgery, among others. SSI is also highly disadvantageous for physicians from the cost-effectiveness standpoint.1
The risk factors associated with infection can be divided into those intrinsic to the patient, such as smoking, diabetes, malnutrition, obesity, rheumatoid arthritis, chronic use ofcorticosteroids, and neoplasms, and extrinsic, such as increased surgical time and high number of professionals in the surgical field.2
Some measures adopted in the intraoperative and immediate postoperative period may help to decrease the rate of postoperative infections. Among them, the maintenance of the aseptic field, attention to hemostasis, devitalized tissue minimization, proper use ofdrains, and antibiotic prophylaxis are highlighted.2
Antibiotic prophylaxis is the main method to prevent this complication. Its importance and efficiency during surgery are known: a significant reduction in the number of infections is observed in patients who receive it.3
Some studies have shown that a single dose of antibiotic is as effective as multiple-dose prophylaxis. However, this is not universally accepted. This study aimed to compare the postoperative results of patients on antibiotic prophylaxis for one and five days that underwent up to three-level lumbar arthrodesis
Material and methods
Forty-three patients were assessed through a prospective, randomized study after approval from the institution’s Research Ethics Committee (#12039513.9.0000.5065). All patients underwent lumbar fusion due to degenerative disc disease for one, two, or three levels. After surgery, patients were assessed on the day of discharge, at the first outpatient follow-up, after two weeks, and 90 days after surgical procedure, where clinical evaluation of the wound and laboratory tests for both groups were carried out.
Inclusion criteria comprised patients who underwent lumbar arthrodesis in up to three levels due to degenerative diseases and who were followed-up at the orthopedic clinic of this institution. Patients who underwent lumbar arthrodesis for reasons other than degenerative disease, such as tumors or fractures, and those who underwent lumbar arthrodesis for more than three levels were excluded.
After inclusion in the study, patients were assigned a number (one or two) by drawing lots, which defined the group they belonged to. Group 1 received antibiotic prophylaxis with first-generation cephalosporin for one day and Group 2, same antibiotic but for five days.
Results of the clinical assessment of the surgical wound and pre- and postoperative laboratory tests (hemoglobin, hematocrit, white blood cell count, neutrophils, erythrocyte
sedimentation rate, C-reactive protein) were used for the analysis. The assessment of the surgical wound indicated the true importance ofsigns such as heat, redness, wound dehiscence, and purulent exudation.
The chi-squared test (2) and binomial tests were used, considering p < 0.05 and n = 1.
Results
The study comprised 43 patients from November 2012 until April 2014; 22 were female, with mean age of 49.9 years (range 16–76 years). The observed complications were SSI, suture dehiscence, cerebrospinal fluid leaks, and exacerbated hyperemia.
In the present study, SSI rates of 2.3% and general complication rates of 27.8% were observed, as described in Table 1.
The following analysis assessed the relationship between postoperative administration of antibiotics in two different periods: Group 1 (24 h) and Group 2 (five days), as shown in Table 2. In this analysis, “normal” and “altered” conditions were considered. “Normal” represents the group that was in perfect condition after the antibiotic administration period, and “altered,” those who had some type of abnormality, such as one-point dehiscence, infection, cerebrospinal fluid rhinorrhea, hyperemia, and seroma.
The chi-squared test, as shown in Table 3, indicates that the hypothesis of association between antibiotic administration period and condition of the patient after this period was rejected (p = 0.924). Thus, there was no association between the fact that the antibiotic was given for either 24 h or five days and patient final status.
However, one question can be raised: was there a difference between the proportions of normal and altered within each antibiotic administration period?
Binomial tests for these proportions, as show in Table 4, indicate that in the 24-h group, there was no difference between the postoperative conditions, with a significance of 0.078 (>0.05).
For the 24-h group, the difference between the proportions ofnormal and altered conditions was also not significant, with a significance of 0.052 (>0.05), as shown in Table 5.
These results corroborate the association test carried out a priori and indicate that longer periods of antibiotic use do not contribute to increased rates of “normal” outcome. However, it must be highlighted that such tests are more reliable when there is a larger number of occurrences for the analyzed categories
Discussion
As discussed by Meyer et al.,2 certain risk factors have been proven to increase the risk of SSI in patients operated for lumbar stenosis. Diabetes mellitus is the most important factor, in addition to advanced age, immunosuppression, smoking, chronic use of corticosteroids, multilevel surgery, obesity, hypertension, and liver cirrhosis. Considering that the overall rate of SSI in spinal surgery is low (<2%),3 the only patient in the study who presented SSI had two risk factors for infection (elderly, hypertensive), corresponding to 1/44 or 2.28% of the sample. Despite the emphasis on drug therapy, prevention of surgical infections goes well beyond antibiotic prophylaxis. No surgeon should underestimate the importance of appropriate preoperative care, following the 1999 Center for Disease Control and Prevention (CDC) SSI prevention guidelines, which recommends a reduction to <24 h of preoperative hospitalization, shaving with trimmer or scissors at <2 h, antibiotic
prophylaxis initiated at up to 1 h, antisepsis of the operative field, and duration of antibiotic prophylaxis <24 h.3,4
Although preoperative antibiotic prophylaxis is effective to prevent bacterial infection, prolonged use of antibiotics is not justified. A meta-analysis by Barker5 did not identify any additional benefit from multiple-dose regimens. The prolonged use of antibiotics increases the risk of resistance of bacterial strains without benefits.6–8 Furthermore, the current orientation for clean spinal surgery is a single prophylactic dose9,10; if a new dose is added, it should not exceed 24 h postoperative.11–13
In the present study, a 24-h antibiotic protocol versus 120-h was proposed; the individual health variables of each subject were disregarded, and the incidence of infection was assessed separately. The results presented demonstrated that there was no difference in the incidence of infection within groups, which does not justify the prolonged use of antibiotics.
Other minor complications were observed in the study. Eight injuries had seroma, one had lush hyperemia, one evolved into cerebrospinal fluid fistula, and one had dehiscence of a suture caused by superficial infection. All these minor complications were not included as SSI because they were not deep, i.e., below the limit of muscular fascia.13
Conclusion
This study demonstrated that a single dose of antibiotic prophylaxis with first-generation cephalosporin is as effective as a pre- and postoperative multiple-dose regimen in lumbar arthrodesis surgery in up to three levels. The costs and risks of subjecting the patient to hospitalization under medication regimen are not justified.
Conflicts of interest
The authors declare no conflicts of interest.
1. Takahashi H, Wada A, Iida Y, Yokoyama Y, Katori S, Hasegawa K, et al. Antimicrobial prophylaxis for spinal surgery. J Orthop Sci. 2009;14(1):40–4. 2. Meyer GPC, Gomes FCP, Lima ALLM, Cristante AF, Marcon RM, et al. Estudo retrospectivo das infecc¸ões pós-operatórias em cirurgia de coluna: correlac¸ão com o número de limpezas cirúrgicas realizadas. Coluna/Columna. 2011;10(2): 127–31. 3. Kim B, Moon SH, Moon ES, Kim HK, Park JO, Cho IJ, et al. Antibiotic microbial prophylaxis for spinal surgery: comparison between 48 and 72-hour amp protocols. Asian Spine J. 2010;4(2):71–6. 4. Hellbusch LC, Helzer-Julin M, Doran SE, Leibrock LG, Long DJ, Puccioni MJ, et al. Single-dose vs multiple-dose antibiotic prophylaxis in instrumented lumbar fusion – a prospective study. Surg Neurol. 2008;70(6):622–7. 5. Barker FG 2nd. Efficacy of prophylactic antibiotic therapy in spinal surgery: a meta-analysis. Neurosurgery. 2002;51(2):391–400. 6. Watters WC 3rd, Baisden J, Bono CM, Heggeness MH, Resnick DK. Antibiotic prophylaxis in spine surgery: an evidence-based clinical guideline for the use of prophylactic antibiotics in spine surgery. Spine J. 2009;9(2):142–6. 7. Petignat C, Francioli P, Harbarth S, Regli L, Porchet F, Reverdin A, et al. Cefuroxime prophylaxis is effective in noninstrumented spine surgery: a double-blind, placebo-controlled study. Spine (Phila Pa 1976). 2008;33(18):1919–24. 8. Mastronardi L, Tatta C. Intraoperative antibiotic prophylaxis in clean spinal surgery: a retrospective analysis in a consecutive series of 973 cases. Surg Neurol. 2004;61(2):129–35. 9. Bowater RJ, Stirling SA, Lilford RJ. Is antibiotic prophylaxis in surgery a generally effective intervention? Testing a generic hypothesis over a set of meta-analyses. Ann Surg. 2009;249(4):551–6. 10. Kato D, Maezawa K, Yonezawa I, Iwase Y, Ikeda H, Nozawa M, et al. Randomized prospective study on prophylactic antibiotics in clean orthopedic surgery in one ward for 1 year. J Orthop Sci. 2006;11(1):20–7. 11. Dobzyniak MA, Fischgrund JS, Hankins S, Herkowitz HN. Single versus multiple dose antibiotic prophylaxis in lumbar disc surgery. Spine (Phila Pa 1976). 2003;28(21): E453–5. 12. Khan IU, Janjua MB, Hasan S, Shah S. Surgical site infection in lumbar surgeries, pre and postoperative antibiotics and length of stay: a case study. J Ayub Med Coll Abbottabad. 2009;21(3):135–8. 13. Mangram AJ, Horan TC, Pearson ML, Silver LC, Jarvis WR. Guideline for Prevention of Surgical Site Infection, 1999: Centers for Diseases Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control. 1999;27:250–69.
