Craniofacial surgeons are operating more frequently in recent years in the management of traumatic injury, neoplasia, and syndromic and nonsyndromic craniofacial dysostosis, owing in part to the earthquakes in Haiti and Chile in 2010 that contributed to the need for craniofacial reconstructive procedures. The incidence of associated craniofacial surgical infections was 14.7% in one study and 8.1% in another, but it varies greatly and may range from 3% to 45%, depending on the number of procedures undertaken during a single anesthesia, surgical duration, and the structures involved. A review published in 2005 demonstrated a rate of 3.2 infections per 100 craniofacial surgical procedures and found that surgical duration longer than 7 hours, closure of skin under tension, use of bovine pericardium, and the presence of more than four surgeons in the operating suite were common risks for development of infection. Determining when an infection has occurred is difficult. The overall facial appearance of the child may be so altered by the surgical intervention and postoperative swelling that even parents may not recognize that infection has occurred. Diagnostic needle aspiration may be helpful. Because infections tend to be caused by bacteria that reside in the sites through which incisions and osteotomies are performed, the main pathogens are skin, paranasal sinus, and oropharyngeal flora. Each additional site that is surgically violated increases the risk for development of an infection. Infections include cellulitis and dehiscence of the wound, infection of subgaleal fluid, osteomyelitis, focal soft tissue abscesses, epidural abscesses, and septicemia. Exposure of harvested bone and use of metal plates, special cements, distraction pin systems, and wires render infection treatment decisions difficult, so follow-up plays a greater role in management of related infections than in management of simple surgical site infections. Routes of antibiotic administration and duration of antibiotic therapy are poorly established. Most procedures have required extensive preoperative planning, and what is done may not be so easily undone. The infectious diseases consultant must be prepared to engage in an ongoing dialogue with the surgeon and the patient’s family, determining what can be removed and at what cost, providing objective feedback about the success of the treatment to that point, and declaring, when needed, that a failure of medical therapy has occurred. Stating dogmatically that all devitalized bone and foreign material must be removed will, in all likelihood, cause the surgeon to delay requesting consultation when infectious diseases services are again needed.
Procedures and Infections
Some children require palatal reconstruction, others need distraction osteogenesis by mandibular distraction pin device systems for mandibular hypoplasia. Some require advancement of large portions of the face. One less commonly performed procedure to correct midfacial retrusion is the frontofacial monobloc advancement. This procedure involves detachment and advancement of the entire facial bony mask and commonly requires a large frontal craniotomy, the bone from which may be shaped to complete the repair or used as needed to form a suitable foundation to which the advanced monobloc can be secured. Osteotomies are performed along the lower portion of the frontal bone and posteriorly along the roof of the orbits, along the lateral and medial inferior walls of the orbits, and through the zygomatic arches, with subsequent pterygomaxillary disjunction. A frontoethmoidal osteotomy divides the posterior portion of the nasal septum to free the monobloc so that it can be advanced and secured in place by wiring it anteriorly to a slightly fore-tilted strip of frontal bone and stabilizing it laterally with wired-in strips of calvarial bone grafts to bridge gaps in the zygomatic arches. Bone blocks in the pterygomaxillary area help to hold the maxillary portion forward. The temporary dead space created in the anterior cranial fossa is problematic in some patients. This procedure is associated with an inherent risk for developing meningitis, which is associated less frequently with the extracranial procedures described later, although meningitis still may occur. An alternative procedure that seeks to avoid entering sinus cavities and the cranium is the subcranial Le Fort III osteotomy. Exposure is provided through a coronal incision with distraction of the soft tissues of the forehead. Osteotomies free part of the medial, lateral, and inferior walls of the orbit and the nasal bridge, and the remainder of the midface bloc is freed by pterygopalatine disjunction and osteotomies of the zygomatic arch and posterior nasal septum. Thus only the midface bloc is brought forward, and interposition grafts, hydroxyapatite, microplates, and wires secure the bloc in the advanced position. As in the frontofacial advancement, split calvarial bone grafts bridge the space in the zygomatic arches. A Le Fort I osteotomy is an isolated maxillary advancement procedure that might additionally be used to change the position of the upper teeth.
Some cases of Treacher Collins syndrome require the integral (simultaneous midfacial and mandibular osteotomies). In this complicated procedure requiring a tracheostomy, the midface osteotomies exclude the temporal, lateral walls of the orbits from the advanced bloc. In addition, osteotomies shaped like a C or inverted V through the mandibular rami with placement of the interposition bone grafts and wiring provide advancement of the mandible. Split calvarial bone grafts subsequently reestablish the zygomatic arches.
Reconstructive materials include bone autograft and solvent-treated allograft, titanium plates and mesh, and alloplasts such as polymethyl methacrylate and hydroxyapatite cements, some of which readily accept bone ingrowth and wires. New materials are in development. In an effort to limit postoperative infection, antibiotics such as tobramycin may be mixed into hydroxyapatite cements, which are released into the surrounding field within the first 24 hours of placement.
In many instances, infection permeates the entire operative field. Donor bone graft sites may be involved in some instances. Bacteria may infect the wound or soft tissue area, may spread by contiguous extension through cortical bone during long periods of contact, or may extend through osteotomies that have disrupted the integrity of the periosteum and cortical bone barriers. Additionally surgical alteration of the local blood supply to the cranial bones through disruption of medullary channels and removal of the adherent periosteum, as well as the presence of hardware required to secure the bony structures in their new locations, can render infection difficult to treat. Repeated or prolonged hospitalizations for previous surgical procedures may predispose to subsequent postoperative infection with multidrug-resistant bacteria. Attempts to reduce the incidence of infection have made the use of parenteral prophylactic perioperative antibiotic regimens for 2 to 5 days commonplace.
The development of meningitis is a concern with many craniofacial procedures; however, the dura provides a significant barrier to infection when painstaking neurosurgical technique is applied during repair. The presence of a cerebrospinal fluid leak is a predisposing factor, and meningitis may be manifested years after the procedure in the case of a leak. No cases of meningitis were identified from a combined report of complications after 567 procedures spanning 6.5 years at Medical City Dallas Hospital and at the Division of Plastic Surgery at the University of Pennsylvania in Philadelphia, primarily for cranial vault remodeling. Similarly, meningitis was not identified from an earlier report of 170 transcranial operations spanning 10 years at the South Australian Cranio-Facial Unit in which 53 accidental dural tears occurred and 32 planned dural openings were performed. Nonetheless meningitis has been documented to occur in association with a frontal abscess with osteomyelitis, subgaleal fluid infection, contamination of cerebrospinal fluid drains, and monobloc advancement.
As with many procedures, longer operative times result in more infections. Staging of surgeries for complicated problems has helped manage the risk for infection. The Australian group mentioned above documented an average operative time of 10.5 hours for patients in whom a postoperative infection developed, which was 2.5 hours longer than operations on patients in whom an infection did not develop. Longer and more complicated monobloc advancement procedures have been associated with infection rates as high as 45%, whereas anterior cranial vault remodeling may be associated with infection rates as low as 2.5%. The dura encountered during primary craniofacial procedures is manipulated more easily and has better vascularization than does the scarred dura encountered in more complicated and laborious secondary procedures, which are associated with higher rates of infection. Additionally craniofacial postoperative infections develop in infants far less frequently than in adults. Of the common procedures, infection remains a relatively rare complication of the less complicated Le Fort I maxillary osteotomy. In a large review of outcomes of 1000 such procedures, only 1.1% developed abscess or related infection. Infections complicating distraction osteogenesis have been reported to occur in 9.5% of cases; however, osteomyelitis or deep infection requiring removal of instrumentation is less common, occurring in 0.5% to 0.9% of cases.
As experience in craniofacial surgery has grown, the reduction in the frequency of infection has been attributed to shortened operative time, attempts to avoid entrance into the contaminated sinus cavities (an easier task in young children, in whom the sinuses often are still poorly developed), and mucosal repair at the end of surgery. The mean time to diagnosis of infection is approximately 10 days.
Microbiology
Procedures that do not violate the mouth or paranasal sinuses, if infected, are usually infected by skin flora. Organisms causing these infections include flora of the skin such as Candida albicans, Staphylococcus aureus (both methicillin-susceptible and methicillin-resistant strains) , Staphylococcus epidermidis, and other coagulase-negative staphylococci , group A β-hemolytic streptococci, and Propionibacterium acnes. Resident flora of the oropharynx such as Bacteroides spp., Corynebacterium spp., and various α-hemolytic streptococci including Streptococcus pneumoniae, enterococci, Morganella morganii, Eikenella corrodens, Haemophilus influenzae, and H. parainfluenzae can be causative, especially in procedures that invade the sinus cavities. In addition, gram-negative organisms, such as Pseudomonas aeruginosa, Escherichia coli, Klebsiella spp., and Acinetobacter calcoaceticus may be involved. Infections are often polymicrobial and may involve bacteria that are resistant or multidrug-resistant to antibiotics. The frequency of infection with Candida spp. is also high and may rival the frequency of infection with more common bacteria.
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