Does preoperative surgical site shaving reduce postoperative surgical‑site infection?

Preoperative Shaving Increases Surgical Site Infection Risk

Preoperative shaving should be avoided—if hair removal is necessary, use electric clippers close to the time of surgery instead. The evidence consistently demonstrates that razor shaving increases surgical site infection rates compared to clipping or no hair removal.

Primary Recommendation

Clipping is strongly preferred over shaving for hair removal. 1 The Enhanced Recovery After Surgery (ERAS) Society guidelines for cardiac surgery explicitly state that meta-analysis of skin preparation and depilation protocols indicates clipping is preferred to shaving, with clipping using electric clippers occurring close to the time of surgery. 1

Evidence Against Shaving

Infection Rate Data

• Shaving increases postoperative infection rates compared to not shaving, with statistically significant differences demonstrated in prospective randomized trials. 2
• In spinal surgery, 4 infections occurred in the shaved group versus only 1 in the unshaved group (P < 0.01). 2
• A systematic review of neurosurgical procedures found strong evidence that preoperative scalp shaving does not confer any benefit against postoperative wound infection and paradoxically may lead to higher rates of infection. 3

Subgroup Vulnerabilities

Certain surgical categories show particularly elevated risk with shaving:

• Clean-contaminated surgeries had significantly higher SSI rates in shaved patients (P = 0.037). 4
• Surgeries lasting less than 2 hours showed significantly higher infection rates with shaving (Fischer's exact = 0.034). 4

Mechanism of Harm

Razor shaving creates microscopic skin trauma that provides entry points for bacteria. 5 Unsatisfactory skin preparation with gross cuts was noted in 7% of shaved patients versus 4% of clipped patients. 5

Implementation Strategy

If Hair Removal is Deemed Necessary:

1. Use electric clippers only 1
2. Perform clipping immediately before surgery (close to the time of operation, not the night before) 1
3. Avoid razor shaving entirely 1

Optimal Approach:

Consider not removing hair at all. 3 Multiple studies recommend that surgeries, including cranial procedures, should be performed without hair removal since it neither contributes benefits to the surgery itself nor decreases infection risk but has considerable cosmetic value for patients. 3

Integration with Infection Prevention Bundle

Hair removal strategy should be part of a comprehensive surgical site infection prevention bundle that includes: 1

• Topical intranasal therapies to eradicate staphylococcal colonization
• Weight-based cephalosporin administration less than 60 minutes before skin incision
• Alcohol-based antiseptic skin preparation 1
• Appropriate timing of antibiotic prophylaxis 6

Common Pitfalls to Avoid

• Never shave the night before surgery—this maximizes time for bacterial colonization of micro-abrasions 1
• Do not assume hair removal is necessary—question this practice for each surgical procedure 3
• Avoid using razors even if clippers are unavailable—leaving hair intact is safer than shaving 3, 2

Special Populations

For clean-contaminated surgeries and procedures under 2 hours duration, avoiding hair removal entirely may be particularly beneficial as these subgroups showed the most significant infection rate differences. 4