Discussion

Antibiotic prophylaxis is an essential component of any multifaceted approach to SSI prevention. Although multiple national and international guidelines govern perioperative decision making, real-world practice varies substantially among surgeons, institutions, and specialties. Reducing SSI risk is certainly a surgical imperative. Antibiotic stewardship is necessary to minimize antibiotic-related adverse events, such as Clostridium difficile infection, acute kidney injury, and the development of antibiotic resistance. Given this potential variability, this study was conducted to assess the current practice of antibiotic prophylaxis in neurosurgery, a field that spans a large variety of surgical procedures. Taken together, our results suggest that antibiotic prophylaxis is close to universal among neurosurgical procedures except in peripheral nerve and emergent surgery. Postoperative prophylaxis, including after closure of the incision and even more than 24 hours after surgery, is commonplace and not in compliance with clinical practice guidelines. Only a minority of surveyed centers routinely screen for MRSA/MSSA. A small number of respondents use vancomycin powder during wound closure.

The aggregate incidence of SSI, including superficial infection, deep infection, and meningitis, after craniotomy with appropriate antibiotic prophylaxis is ∼5%. ^{Reference Korinek, Golmard and Elcheick7} Given uniform trends in both prospective and retrospective assessments of prophylaxis in cranial neurosurgery, a single dose of preoperative prophylaxis has been recommended. ^{Reference Bratzler, Dellinger and Olsen2} Guideline recommendations for both adult and pediatric shunt procedures are similar. Postoperative prophylaxis, either up to or beyond 24 hours after closure of the incision, was used by 65% of respondents’ institutions. A similar rate of 63% was recently reported in a Japanese survey of neurosurgical practice; even among patients who received postoperative antibiotics, a plurality (40%) actually received these antibiotics for 3 days after surgery. ^{Reference Matsuda, Ikawa and Ohba6}

National guidelines also recommend antibiotic prophylaxis for both instrumented and noninstrumented spinal procedures, though it is relatively well known that noninstrumented procedures carry a lower risk of SSI ^{Reference Bratzler, Dellinger and Olsen2} . In our survey, preoperative prophylaxis was commonly used for both subtypes of spine surgery; however, rates of postoperative antibiotic administration differed between instrumented (78%) and noninstrumented (48%) procedures. This difference may reflect continuing systemic antibiotics the entire duration of time for which surgical drains are in place postoperatively. ^{Reference Lewis, Lin, James, Hill, Sen and Pacione8}

The greatest variation in our survey was in peripheral nerve surgery. In these procedures, many of which are also performed by orthopedic or plastic surgeons in both inpatient and outpatient settings, the role of antibiotic prophylaxis is unclear due to the low incidence of SSI. ^{Reference Bratzler, Dellinger and Olsen2} Pre- and perioperative antibiotic prophylaxis for peripheral nerve surgeries may be used more commonly by neurosurgeons who may be more inclined to do these procedures in an outpatient setting. However, we did not survey other surgical specialties to confirm this hypothesis.

Overall, ∼15%–20% of patients undergoing emergent neurosurgical procedures did not receive antibiotic prophylaxis. Although patients undergoing emergent procedures are likely at increased risk of SSI, they are also at high risk for receiving nonstandardized perioperative prophylaxis due to the fragmented and unpredictable nature of their care. Nevertheless, adherence to guidelines, even under these circumstances, has been associated with decreased risk of SSI. ^{Reference Smith, Fox and Fakhro9}

Finally, MRSA and MSSA screening and/or decolonization and vancomycin powder use during wound closure are emerging practices that have not yet been included in formal national guidelines despite evidence in favor of both practices. The results of our survey suggest that these practices are not widespread.

This study has limitations. It was a survey of SRN members, and practices from nonmember institutions were not included. The overall response rate was relatively low. Nevertheless, we believe that the results of this survey point to some areas of concern and reflect the gaps between guidelines and clinical practice in this, and likely other, surgical subspecialties.

In conclusion, antibacterial prophylaxis for neurosurgical procedures varies widely, as does MRSA and MSSA screening/decolonization and vancomycin powder use during wound closure.