Introduction
Surgical antibiotic prophylaxis is defined as the administration of an antimicrobial
agent prior to contamination of previously sterile spaces and fluids[1]. The purpose of this procedure is to eradicate transient organisms with the potential
to colonize and slow the growth of resident microbes, thus preventing surgical infection[1]. Antibiotic prophylaxis should be performed in conjunction with any surgery associated
with a high risk for infection or when the consequences of infection would be disastrous
(even if the risk for infection is low)[2].
According to the classification scheme of the American National Academy of Science
and the National Research, surgical wounds are classified as clean injuries (no violation
of septic technique, no manipulation of the gastrointestinal tract or genitourinary,
or respiratory system, and no sign of inflammation), clean-contaminated injuries (manipulation
of the digestive or respiratory tract and/or minimal violation of sterile technique),
contaminated injuries (active inflammation and/or violation of sterile technique),
or dirty injuries (purulent inflammation)[3].
The choice of antibiotic is influenced by the need for the drug to be administered
intravenously to be effective against agents that might colonize the surgical site
and to be bactericidal, achieve adequate tissue levels, cause minimal side effects,
be relatively cost-effective (half-life), and have a minimal impact on the local colonizers
of the patient and the hospital[4]. Cefazolin meets all of these requirements and is thus the first choice for surgical
prophylaxis for clean-contaminated head and neck surgeries according to the recommendations
of the Antimicrobial Agents Committee of the Surgical Infections Society and American
Society of Health-System Pharmacists of 1999. Clindamycin should be used in patients
allergic to beta-lactams. Amoxicillin-clavulanate is the first choice for surgeries
with risk for contamination by anaerobes[4].
Antibiotic prophylaxis should be initiated during anesthesia. The dose should be repeated
only if the surgical time exceeds the half-life of the antibiotic or if major bleeding
(10–20% of the blood volume) occurs. Prolonged antibiotic prophylaxis does not enhance
the prevention of surgical infection and is associated with higher levels of bacterial
resistance[5]. Furthermore, the indiscriminate use of antibiotics can lead to serious complications
such as toxic reactions, reduces the stimulus to antibody formation, and is financially
burdensome[6].
This article will discuss the main aspects of antibiotic prophylaxis, with an emphasis
on otolaryngologic surgeries, and its main objective is to develop a guide for the
use of antibiotic prophylaxis in otolaryngologic surgeries in order to reduce the
complications of the indiscriminate use of antibiotics.
Review
Pharyngeal surgeries
The most common pharyngeal colonizers are Gram- positive cocci, mainly Peptostreptococcus and Peptococcus spp., and anaerobic bacteria[4]
[7]. In the oropharynx, anaerobes are 10 times more numerous than aerobes[7]. Gram-negative bacteria are rare in the secretions of healthy individuals; nevertheless,
organisms such as Klebsiella, Pseudomonas, Proteus, and some Bacteroides species (other than B. fragilis) are common colonizers of the aerodigestive tracts of oncology patients[8].
Adenotonsillectomy
Adenotonsillectomy has high immediate postoperative morbidity, including sore throat,
dysphagia, fever, halitosis, weight loss, and reluctance to take food orally[9.10].
Colonization of the open tonsillar fossa by the oropharyngeal flora has been suggested
to produce a local inflammatory response that exacerbates postoperative pain[9]. This idea inspired several studies of the relationship between the perioperative
use of antibiotics and postoperative morbidity[11].
According to OBESO S et al. in 2010[12], the administration of antibiotics in pediatric patients significantly reduced the
early return to normal diet (level of evidence A), did not reduce pain or the risk
for bleeding (level A) and did not provide major benefits over the postoperative application
of topical antibiotics (level A), while topical antibiotics were more effective than
systemic antibiotics at reducing pain (level B).
Although the findings of individual studies vary, there is no evidence to support
a consistent, clinically important, beneficial effect of antibiotics on the major
morbid outcomes of tonsillectomy. The limited benefit of antibiotics observed may
have resulted from a positive bias introduced by several important methodological
shortcomings in the included trials. Therefore, based on existing evidence, we would
advocate against the routine prescription of antibiotics to patients undergoing tonsillectomy[13].
The only established reason for antibiotic prophylaxis in tonsillectomy is to prevent
endocarditis and sepsis in patients with orthopedic implants or prosthetic valves
or a history of previous endocarditis, congenital heart disease, or transplant with
valvulopathy[11].
Uvulopalatopharyngoplasty
There are no controlled studies showing a benefit or necessity of perioperative antibiotic
administration. As the procedure involves an incision in the pharyngeal mucosa, with
the consequent risk for infection by anaerobes, we recommend the use of prophylactic
antibiotics in this surgery[14].
Rhinologic surgeries
Even healthy individuals have potentially pathogenic species such as S. aureus, Klebsiella spp., and Escherichia coli in their nostrils in 77% of cases. Between 18% and 50% of patients are colonized
by S. aureus
[15].
Septoplasty
There are few studies demonstrating the necessity or effectiveness of antibiotic prophylaxis
in nasal surgery. Many authors therefore consider it unnecessary[6].
Surgical procedures on the aerodigestive tract are considered potentially contaminated
and may be associated with postoperative infectious complications such as toxic shock
syndrome, osteomyelitis, meningitis, and cavernous sinus thrombosis[6]. Bacteremia can lead to endocarditis in at-risk patients, such as patients with
valvular prostheses, cardiac transplants, or histories of endocarditis. An antibiotic
is recommended in such cases[16]
[17].
Staphylococcal toxic shock syndrome is extremely rare, with an estimated incidence
of 0.0002%, but there is evidence that it can be prevented by the prophylactic use
of antibiotics. There are no studies showing the incidence of bacteremia when nasal
packing antibiotics are used[12].
Scientific evidence shows that systemic administration of antibiotics does not reduce
morbidity or infection after septoplasty (level A), antibiotics do not protect against
S. aureus colonization and do contribute to decreased levels of normal flora[18], antibiotics do not seem to confer beneficial flora changes[18], and topical antibiotics decrease colonization of nasal septoplasty sites (level
A)[12].
No studies showed a benefit of the perioperative use of systemic antibiotics in septoplasty[6]. Therefore, septal surgery does not require routine antibiotic prophylaxis because
of the low risk for infection[19].
Rhinoplasty and other nasal surgeries
Antibiotic prophylaxis is not necessary in primary rhinoplasty without grafting or
septoplasty.
In complex nasal surgeries, such as secondary septorhinoplasty, nasal graft surgery,
or the repair of septal defects, the infection rate reaches 27%[20]. These patients might benefit from the use of antibiotics, but there are no studies
comparing the perioperative use of antibiotics versus placebo[20]. Although the benefits of prophylactic antibiotics for this type of indication remain
uncertain, most authors recommend their use in such cases[20].
Laryngeal surgeries
Isolates of bacteria from infected clean-contaminated head and neck surgery wounds
commonly have polymicrobial characteristics. Gram-positive bacteria are most frequently
isolated, followed by Gram-negative species and anaerobes[21].
Laryngeal microsurgery
The infection rate is low, and there are no clinical trials showing a benefit of antibiotic
use in these surgeries.
Other laryngeal surgeries
Antibiotic therapy is necessary in complex laryngeal surgeries such as total laryngectomy.
The presence of potentially pathogenic bacteria, the duration of the procedure, and
the use of flaps lead to a high rate of infection in the absence of antibiotic[22].
Endoscopic sinus surgery
There are potentially pathogenic species such as S. aureus, Klebsiella spp., and/or Escherichia coli in the nostrils in 77% of cases[23]. In patients diagnosed with chronic rhinosinusitis, repeated antibiotic therapy
has selected for resistant pathogenic species. Up to 90% of patients undergoing endoscopic
sinonasal surgery produce positive cultures; most of the species isolated are resistant
to penicillin, and 65% are resistant to cephalosporins[24].
Endoscopic sinus surgery for chronic rhinosinusitis
We suggest amoxicillin-clavulanate and prednisolone for 14 days, beginning 7 days
before surgery, for the treatment of chronic infectious processes and reduction of
intraoperative complications[25] and to improve the postoperative results. Antibiotic prophylaxis is recommended
during anesthesia.
Endoscopic surgery for closure of cerebrospinal fluid fistulae
Perioperative systemic administration of antibiotics reduces the incidence of postoperative
infection[12].
Endoscopic sphenopalatine artery ligation
Antibiotics are not recommended for this procedure because it is considered a clean
surgery[3].
Dacryocystorhinostomy
Infection occurs after 8% of surgeries that open the lacrimal sac. Antibiotic administration
can reduce this rate by up to 5-fold[26], justifying the use of antibiotic prophylaxis.
Resection of nasal tumors by an external approach
Antibiotics are recommended because of the high rate of infectious complications[27].
Otologic surgeries
Postoperative infection in otology manifests as loss of the neotympanic graft, labyrinthitis,
surgical wound infection, or the occurrence of otitis media or external otitis.
Verschuur et al.[28] have proposed the following classification scheme: clean surgery: myringoplasty,
stapedectomy, ossicular reconstruction, and dry ears; clean-contaminated or dirty
surgery: ears with preoperative suppuration (chronic otitis media with or without
cholesteatoma).
The Pseudomonas species isolated from the ear are highly sensitive to polymyxin B, ciprofloxacin,
and gentamicin, while the Staphylococcus species are sensitive to cloxacillin, gentamicin, and ciprofloxacin. Most isolates
obtained during episodes of otorrhea are polymicrobial. The microbiological profile
of otitis media with cholesteatoma is similar to that of simple chronic otitis media
except that anaerobes, mainly Bacteroides and Peptococcus, are more frequent; anaerobes have been isolated in up to two-thirds of cases of otorrhea with cholesteatoma.
Although otitis media with effusion is assumed not to present with active infection,
microorganisms, most frequently Haemophilus influenza, Moraxella catarrhalis, and Streptococcus pneumoniae, are isolated in up to 50% of cases.
The incidence of postoperative infection has been estimated at less than 5% after
clean surgery but between 7 and 14% after clean-contaminated surgery[29]. The most common infectious agents encountered after clean otologic surgery are
species of S. aureus and other Gram-positive bacteria[30]. The bacteria most frequently isolated from cases of chronic otitis media without
cholesteatoma are Pseudomonas aeruginosa and Staphylococcus species, mainly S. aureus. The other Gram-negative organisms encountered are, in order of frequency, Klebsiella, Proteus, and Haemophilus; the remaining Gram-positive bacteria are predominantly Streptococci, and the isolation of anaerobes is uncommon[31].
Chronic otitis media with cholesteatoma differs from that without in that anaerobes,
especially Bacteroides and Peptococcus, are the most common isolates; otherwise, the bacteriological profile is similar[28].
Although serous otitis media involves no active infection, microorganisms, most frequently
Haemophilus influenzae, M. catarrhalis, and Streptococcus pneumoniae, are isolated in 50% of cases[31].
According to Obeso et al. in 2010[12], systemic administration of antibiotics does not reduce the incidence of infection
after clean (level A) or clean-contaminated (level B) surgery and provides no benefit
over topical antibiotic treatment in clean-contaminated surgery (level B); perioperative
systemic administration of antibiotics did reduce infection in cases of clean-contaminated
surgery with positive preoperative cultures (level B).
Tympanoplasty
There is no evidence that perioperative systemic administration of antibiotics decreases
the incidence of infection[12].
Mastoidectomy
Antibiotic use is always recommended. In cases with perioperative otorrhea, antibiotics
should be administered post-operatively[12].
Stapedotomy
There is no evidence to recommend the perioperative use of systemic antibiotics in
patients undergoing clean otologic surgery[28]. However, antibiotic prophylaxis is recommended in cases in which a surgical infection
could evolve with serious consequences, such as deafness or labyrinthitis.
Cochlear Implants
Cochlear implant surgery is considered a clean surgery, and there are no randomized
studies comparing the incidence of local infection between patients with and without
antibiotic treatment[11]. Perioperative systemic administration of antibiotics has been suggested to reduce
the incidence of meningitis[12].
Ossicular Reconstruction
Ossicular reconstruction is considered a clean surgery[28]. Perioperative systemic administration of antibiotics is not recommended because
the incidence of infection is low[12].
Otoplasty
Otoplasty is considered a clean surgery. Careful asepsis and antisepsis are essential
for preventing infection. Infection of either the skin or subcutaneous tissue or perichondritis
is unusual after otoplasty[26].
Insertion of transtympanic drainage tubes
According to Verschuur et al., ears without effusion are considered clean, those with
seromucous effusion clean-contaminated, and those with purulent effusion dirty[28]. Several well-designed studies have shown no significant difference in the incidence
of otorrhea between patients treated postoperatively with oral or topical antibiotics.
As the efficacy of intraoperative irrigation with saline solution was confirmed in
another randomized clinical trial, there is a level of evidence of “A” to recommend
washing the ear with this solution[12].
Surgery on the salivary glands
Some surgeries, such as parotidectomy and resection of the submandibular glands, are
considered clean[3]. Antibiotic prophylaxis is not routinely recommended in such cases[32].
