Surgical site infections (SSIs) result in significant patient morbidity and costs (1,2). The Centers for Disease Control and Prevention (CDC) classifies SSIs into incisional and organ/ space; incisional SSIs are further subdivided into those involving the skin and subcutaneous tissue only (superficial) and those involving deep soft tissues (e.g., fascia and muscle). Organ space would include involvement of any part of the deeper anatomy (e.g., bone) manipulated during the surgery (3). In the cervical spine, rates of SSI may be as low as 1% in anterior cervical surgery and up to 18% in posterior cervical surgery (4,5). Specific variables identified preoperatively, intraoperatively, and postoperatively have been identified that can significantly decrease rates of SSIs. A significant number of spinal infections could potentially be averted with appropriate screening and optimization of preoperative risk factors (6). This review focuses on preoperative patient optimization and surgical (intraoperative) factors that can be utilized to prevent SSI, with particular focus on posterior and anterior cervical spine surgery.
The need to optimize patients preoperatively with the goal of improving surgical outcomes is widely recognized. From an infection standpoint, preoperative optimization includes smoking cessation, glycemic control, malnutrition/obesity management, and screening and decolonization of organisms (7,8).
Tobacco smoking is associated with higher perioperative complications and morbidity postoperatively. Smoking significantly increases the risk of SSI after spine surgery by several mechanisms including vasoconstriction and local tissue hypoxia (6,9-11). In a study looking at 160 patients following anterior cervical corpectomy, Lau et al. found that smoking is independently associated with higher perioperative complications, and current smokers had a significantly higher rate of infections compared to nonsmokers and quitters (12). There is still a benefit to having patients quit smoking prior to surgery, demonstrated by a study that found that surgical complications were nearly halved in patients who stopped smoking prior to surgery compared to current smokers (13). Smoking cessation is a critical modifiable risk factor and should take place at least 4 weeks prior to surgery to be significantly important in decreasing infection risk (14).
Diabetes and glucose control
Diabetes mellitus is a chronic multi-system disease that directly affects both the peripheral nervous system and the microvascular system. Poor wound healing complications secondary to diabetes have been well described, although studies have focused more on the lumbar spine (15). Meng et al. showed significantly higher rates of infection among diabetic patients compared to nondiabetic patients after spine surgery in general (OR 2.04; 95% CI, 1.69–2.46) (7,16). In the lumbar spine, patients with a hemoglobin (Hb) A1C level of 7.5% or above had a significantly higher risk for development of SSI compared with those with HbA1C level less than 7.5% (OR 2.9; 95% CI, 1.8–4.9; P<0.01) (17). In an assessment evaluating key predictors of perioperative complications in patients with myelopathy, Tetreault et al. performed a survey of the AOSpine community and found that in 916 participants, 95% of respondents felt that the presence of diabetes are at higher risk for developing wound infections (18). Worley et al. performed a retrospective study of over 5,900 surgical cervical spondylotic myelopathy patients and found that diabetes is an independent driver associated with extended hospital length of stay and peri-operative complications. Although type and severity of diabetes was not a predictor for complication, patients with insulin-dependent diabetes were associated with an increased incidence of wound complications specifically (19). Another recent NSQIP study showed that patients with diabetes and higher ASA class were at increased risk for extended hospital length of stay and readmission within 30 days (20). Another NSQIP study of over 5,000 patients, however, did not find diabetes to be predictive of developing SSI in the cervical spine (21). Further study is required to specifically delineate the relationship of blood glucose monitoring and development of SSI in cervical spine surgery to inform guidelines.
Although obesity is a well-known risk factor for development of SSI following lumbar spine surgery (7,22,23), less is known with regards to impact of body mass index (BMI) and cervical spine surgery. In a recent study looking at BMI and posterior cervical fusions, Sridharan et al. found significantly higher rates of deep SSIs (OR 4.61, P<0.05) in patients with a BMI ≥35.0 vs. BMI <25.0 (24). In a NSQIP study of over 5,000 patients, Sebastian et al. found that BMI >35, chronic steroid use, albumin <3, and hematocrit <33 were all associated with significantly higher rates of SSI in posterior cervical surgery (21). Similar to the lumbar spine, increased tissue necrosis from retraction injury in posterior cervical surgery may be a contributing factor (25). Further, increased BMI makes surgical exposures larger and more difficult thus increasing retraction time and operative time, resulting in seroma formation and prolonged wound drainage (26,27). Mehta et al. found that thickness of subcutaneous fat is an independent risk factor for infection in cervical spine surgery (28). Further, even in obese patients, malnutrition and hypoalbuminemia can be present (29), due to inadequate protein intake despite excessive calorie consumption (6).
Preoperative bacterial screening
Gram positive bacteria are the most common organisms in spinal SSI (30). Due to the continued preponderance of methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) SSIs, current prevention screening protocols focus on these organisms. Nasal swab with culture 30 days prior to surgery may be obtained. Specific protocols may vary and be surgeon or center-dependent, but one protocol for patients with a positive culture is to treat with a 5-day course of 2% mupirocin ointment twice daily, combined with 2% chlorhexidine gluconate scrub daily for 5 days preceding surgery (6,31-33).
Effective preoperative antimicrobial prophylaxis depends on the type, timing, dose, and redosing of the antibiotic (34-37). The timing and administration of prophylactic antibiotics within 30 minutes of surgical incision has been shown to significantly decrease the risk of SSI when compared to the timeframe of 30–60 minutes prior to incision (38). The standard antibiotic of choice is cefazolin, a first-generation cephalosporin, targeting treatment of gram positive bacteria (staphylococcus) (39). Antibiotic dosage needs to be adjusted appropriately in obese patients (40,41), with redosing every 4 hours (42).
Posterior cervical spine surgery
Posterior cervical spine surgery carries a much higher infection risk compared to anterior cervical procedures, with a reported infection rate up to 18% (5). This seems to be approach related, as opposed to the specific operation itself, as was found in a study comparing SSI rates in posterior cervical decompression vs. laminoplasty vs. arthrodesis in a NSQIP cohort of over 5,000 patients (21). Several potential factors contributing to the dramatic increase in infection for posterior cervical approaches include stripping of paraspinal cervical muscles and formation of dead space due to inadequate soft tissue approximation during wound closure. We present below some specific surgical techniques utilized by the senior author (KDR) during exposure and closure, that have dramatically lowered if not eliminated infections related to posterior cervical spine procedures, regardless of the case (43). Since 2005, in over 1,000 posterior cervical cases, there has not been a single posterior post-operative infection following the techniques below.
Skin preparation begins with the patient shaving 1 to 2 days before the surgery, which allows the skin to heal and eliminates loose hair in the operating room. The surgical site is squared off with plastic drapes and preliminary preparation with alcohol foam is used over the surgical site and the surrounding plastic drapes. Preoperative skin preparation with iodine, chlorhexidine, and alcohol compounds are the most commonly used preparations used to sterilize the skin just prior to skin incision. In a recent meta-analysis, Sidhwa et al. found that alcohol-based agents are generally superior to aqueous solutions (44). Use of either DuraPrep or ChloraPrep therefore would provide adequate intraoperative skin preparation.
The senior author (KDR) routinely uses a microscope from skin incision to wound closure. During exposure, the dissection is carried out using monopolar electrocautery on “cut” and every effort is made to preserve tissue vascularity and minimize trauma. Dissection is maintained in the avascular, amuscular midline plane to minimize bleeding and the need for electrocoagulation. Positioning the neck in flexion, if not otherwise contraindicated, significantly helps with maintaining the dissection in the avascular amuscular plane. Once this is carried down to the bifid spinous processes, the lateral tissue attachments of the bifid processes are preserved, and the tip of the bony bifid processes are cut with a bone cutter. The paraspinal muscle, attached to the tip of the cut spinous process is tagged with sutures and dissected sub-periosteally. These tips of the bifid processes attached to paraspinal muscles will serve as muscle anchor points and facilitate muscle re-approximation during the wound closure stage. Use of smooth self-retaining retractors are recommended, as opposed to sharp retractors. It is preferable to use hemostatic agents and cottonoid patties for hemostasis, as opposed to electrocautery whenever possible to minimize creation of de-vascularized tissue. Throughout the procedure, frequent irrigation is used to keep the tissues moist and to wash away any bacteria.
During closure, intra-wound vancomycin and cefazolin powder (1 gram, each) is routinely applied. If a gram-negative organism is suspected or the patient is allergic to cephalosporins, one can use Tobramycin (nebcin 7 mg/kg for patients with normal renal function). Dilute betadine irrigation may be considered as a simple, yet inexpensive form of SSI prophylaxis (45). Topical vancomycin provides a high local concentration of vancomycin with minimal systemic absorption. Intrawound vancomycin powder is applied subfascially, as well as suprafascially and provides a high local concentration of vancomycin (46-50). Surgical drain is placed to decrease post-operative seroma/hematoma formation. The use of intra-wound antibiotics and drains will substantially decrease but not eliminate infections. To eliminate infections, a multi-layered closure to eliminate dead space must be accomplished. The paraspinal muscles are first re-approximated by suturing around the “tagged” bifid processes during initial exposure on either side using 0-Vicryl suture and tying them together to pull the muscles back to the midline. The muscle sheaths, and not the muscle itself, is then pulled together using 0-Vicryl sutures to strengthen the muscle re-approximation. The fascial layer is then tightly closed with interrupted sutures in multiple layers. Subcutaneous layers are then brought together using 2-0 Vicryl sutures. Of note, each layer is tacked down to the previous layer, obliterating the dead space which can be space for hematoma, seroma, or nidus for infection. The skin is closed with a running 3-0 Monocryl suture and reinforced with Steri-strips and sterile dressing. In the senior author’s clinical practice, it is not unusual to use over 140 sutures to close a 6” posterior cervical wound. Surgical drain is removed when output is less than 30 cc per 8-hour shift, and postoperative antibiotics are continued for 24 hours post-operatively. Using the above technique will result in elimination of SSI in all but the most heavily contaminated cases.
Anterior cervical spine surgery
SSI associated with anterior cervical spine procedures are much rarer than posterior cervical SSIs with a reported prevalence of 0.1% to 1.6% in the literature.(51) Patients with anterior cervical SSI may present with neck and throat pain, incisional erythema and induration, wound drainage, fevers, chills, odynophagia, dysphagia, and possible neurological deficit due to epidural abscess. Further, anterior cervical SSI can often be present in the setting of esophageal injury, which is also very rare with an estimated prevalence of 0.02% to 1.15% of anterior cervical cases (1). Esophageal perforation should be ruled out when anterior cervical SSI is encountered and prompt treatment should be carried out to optimize clinical outcomes.
Like other spine surgeries, long operative time is a risk factor for anterior SSI due to increased bacterial load from the open wound, and specifically greater than 3 hours for anterior cervical surgery. After transverse incision along a neck crease and splitting of the platysma, meticulous dissection in the avascular plane between the anterior cervical musculature (specifically, the avascular plane between SCM laterally and strap muscles medially) can help to minimize surgical dead space and reduce formation of post-operative seroma/hematoma which can serve as a nidus for infection. Adequate release of longus coli muscle cuffs bilaterally and proper retractor placement can help to optimize surgical exposure and minimize the risk of iatrogenic esophageal injury. Excessive retraction of the tracheoesophageal bundle should be avoided and intermittent release of retractors during surgery can help to reduce post-operative dysphagia. The high-speed burr should not be used outside the disc space due to the potential risk of prevertebral soft tissue getting caught by the shaft of the high-speed burr and possible esophageal injury. During closure, vancomycin and ancef powder can be placed in the wound to further reduce risk of infection. This is used whenever we place intrawound steroids to decrease dysphagia. The senior author (KDR) prefers to use a ¼” Penrose drain, which has a larger diameter and is less likely to be clogged. The closure is performed carefully with approximation of the platysma and the skin.
SSI following spine surgery may lead to significant morbidity, mortality, and healthcare costs. Preoperative optimization includes smoking cessation, strict glucose control, weight loss, nutritional optimization, and MRSA decolonization. Intraoperative optimization includes preoperative antibiotics, skin antisepsis, meticulous dissection and closure, betadine irrigation, vancomycin powder, and use of closed suction drains. With careful attention to patient and surgeon factors, it is possible to significantly reduce SSI rates following spine surgery.
Provenance and Peer Review: This article was commissioned by the Guest Editors (Lee A. Tan and Ilyas S. Aleem) for the series “Advanced Techniques in Complex Cervical Spine Surgery” published in Journal of Spine Surgery. The article was sent for external peer review organized by the Guest Editors and the editorial office.
Conflicts of Interest: The series “Advanced Techniques in Complex Cervical Spine Surgery” was commissioned by the editorial office without any funding or sponsorship. LAT serves as the unpaid editorial board member of Journal of Spine Surgery from Jan. 2019 to Jan. 2021. LAT and ISA served as the unpaid Guest Editors of the series. The other authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
- Khoshbin A, So JP, Aleem IS, et al. Antibiotic Prophylaxis to Prevent Surgical Site Infections in Children: A Prospective Cohort Study. Ann Surg 2015;262:397-402. [Crossref] [PubMed]
- Umscheid CA, Mitchell MD, Doshi JA, et al. Estimating the proportion of healthcare-associated infections that are reasonably preventable and the related mortality and costs. Infect Control Hosp Epidemiol 2011;32:101-14. [Crossref] [PubMed]
- Horan TC, Gaynes RP, Martone WJ, et al. CDC definitions of nosocomial surgical site infections, 1992: a modification of CDC definitions of surgical wound infections. Infect Control Hosp Epidemiol 1992;13:606-8. [Crossref] [PubMed]
- Che W, Li RY, Dong J. Progress in diagnosis and treatment of cervical postoperative infection. Orthop Surg 2011;3:152-7. [Crossref] [PubMed]
- Barnes M, Liew S. The incidence of infection after posterior cervical spine surgery: a 10 year review. Global Spine J 2012;2:3-6. [Crossref] [PubMed]
- Nasser R, Kosty JA, Shah S, et al. Risk Factors and Prevention of Surgical Site Infections Following Spinal Procedures. Global Spine J 2018;8:44S-8S. [Crossref] [PubMed]
- Meng F, Cao J, Meng X. Risk factors for surgical site infections following spinal surgery. J Clin Neurosci 2015;22:1862-6. [Crossref] [PubMed]
- Xing D, Ma JX, Ma XL, et al. A methodological, systematic review of evidence-based independent risk factors for surgical site infections after spinal surgery. Eur Spine J 2013;22:605-15. [Crossref] [PubMed]
- Jensen JA, Goodson WH, Hopf HW, et al. Cigarette smoking decreases tissue oxygen. Arch Surg 1991;126:1131-4. [Crossref] [PubMed]
- Sørensen LT, Jorgensen S, Petersen LJ, et al. Acute effects of nicotine and smoking on blood flow, tissue oxygen, and aerobe metabolism of the skin and subcutis. J Surg Res 2009;152:224-30. [Crossref] [PubMed]
- Jackson KL 2nd, Devine JG. The Effects of Smoking and Smoking Cessation on Spine Surgery: A Systematic Review of the Literature. Global Spine J 2016;6:695-701. [Crossref] [PubMed]
- Lau D, Chou D, Ziewacz JE, et al. The effects of smoking on perioperative outcomes and pseudarthrosis following anterior cervical corpectomy: Clinical article. J Neurosurg Spine 2014;21:547-58. [Crossref] [PubMed]
- Thomsen T, Tonnesen H, Moller AM. Effect of preoperative smoking cessation interventions on postoperative complications and smoking cessation. Br J Surg 2009;96:451-61. [Crossref] [PubMed]
- Thomsen T, Villebro N, Moller AM. Interventions for preoperative smoking cessation. Cochrane Database Syst Rev 2014.CD002294. [PubMed]
- Goodson WH 3rd, Hung TK. Studies of wound healing in experimental diabetes mellitus. J Surg Res 1977;22:221-7. [Crossref] [PubMed]
- Armaghani SJ, Archer KR, Rolfe R, et al. Diabetes Is Related to Worse Patient-Reported Outcomes at Two Years Following Spine Surgery. J Bone Joint Surg Am 2016;98:15-22. [Crossref] [PubMed]
- Cancienne JM, Werner BC, Chen DQ, et al. Perioperative hemoglobin A1c as a predictor of deep infection following single-level lumbar decompression in patients with diabetes. Spine J 2017;17:1100-5. [Crossref] [PubMed]
- Tetreault L, Nouri A, Singh A, et al. An Assessment of the Key Predictors of Perioperative Complications in Patients with Cervical Spondylotic Myelopathy Undergoing Surgical Treatment: Results from a Survey of 916 AOSpine International Members. World Neurosurg 2015;83:679-90. [Crossref] [PubMed]
- Worley N, Buza J, Jalai CM, et al. Diabetes as an Independent Predictor for Extended Length of Hospital Stay and Increased Adverse Post-Operative Events in Patients Treated Surgically for Cervical Spondylotic Myelopathy. Int J Spine Surg 2017;11:10. [Crossref] [PubMed]
- Passias PG, Jalai CM, Worley N, et al. Predictors of Hospital Length of Stay and 30-Day Readmission in Cervical Spondylotic Myelopathy Patients: An Analysis of 3057 Patients Using the ACS-NSQIP Database. World Neurosurg 2018;110:e450-8. [Crossref] [PubMed]
- Sebastian A, Huddleston P 3rd, Kakar S, et al. Risk factors for surgical site infection after posterior cervical spine surgery: an analysis of 5,441 patients from the ACS NSQIP 2005-2012. Spine J 2016;16:504-9. [Crossref] [PubMed]
- Ogden CL, Carroll MD, Kit BK, et al. Prevalence of childhood and adult obesity in the United States, 2011-2012. JAMA 2014;311:806-14. [Crossref] [PubMed]
- Jackson KL 2nd, Devine JG. The Effects of Obesity on Spine Surgery: A Systematic Review of the Literature. Global Spine J 2016;6:394-400. [Crossref] [PubMed]
- Sridharan M, Malik AT, Kim J, et al. Does Increasing Body Mass Index (BMI) correlate with Adverse Outcomes following Posterior Cervical Fusions? World Neurosurg 2020;133:e789-95. [Crossref] [PubMed]
- Abdallah DY, Jadaan MM, McCabe JP. Body mass index and risk of surgical site infection following spine surgery: a meta-analysis. Eur Spine J 2013;22:2800-9. [Crossref] [PubMed]
- Moucha CS, Clyburn TA, Evans RP, et al. Modifiable risk factors for surgical site infection. Instr Course Lect 2011;60:557-64. [PubMed]
- Patel VP, Walsh M, Sehgal B, et al. Factors associated with prolonged wound drainage after primary total hip and knee arthroplasty. J Bone Joint Surg Am 2007;89:33-8. [Crossref] [PubMed]
- Mehta AI, Babu R, Sharma R, et al. Thickness of subcutaneous fat as a risk factor for infection in cervical spine fusion surgery. J Bone Joint Surg Am 2013;95:323-8. [Crossref] [PubMed]
- Bohl DD, Shen MR, Mayo BC, et al. Malnutrition Predicts Infectious and Wound Complications Following Posterior Lumbar Spinal Fusion. Spine (Phila Pa 1976) 2016;41:1693-9. [Crossref] [PubMed]
- Mirzashahi B, Chehrassan M, Mortazavi SMJ. Intrawound application of vancomycin changes the responsible germ in elective spine surgery without significant effect on the rate of infection: a randomized prospective study. Musculoskelet Surg 2018;102:35-9. [PubMed]
- Kim DH, Spencer M, Davidson SM, et al. Institutional prescreening for detection and eradication of methicillin-resistant Staphylococcus aureus in patients undergoing elective orthopaedic surgery. J Bone Joint Surg Am 2010;92:1820-6. [Crossref] [PubMed]
- Agarwal N, Agarwal P, Querry A, et al. Implementation of an infection prevention bundle and increased physician awareness improves surgical outcomes and reduces costs associated with spine surgery. J Neurosurg Spine 2018;29:108-14. [Crossref] [PubMed]
- Tomov M, Wanderman N, Berbari E, et al. An empiric analysis of 5 counter measures against surgical site infections following spine surgery-a pragmatic approach and review of the literature. Spine J 2019;19:267-75. [Crossref] [PubMed]
- Fogelberg EV, Zitzmann EK, Stinchfield FE. Prophylactic penicillin in orthopaedic surgery. J Bone Joint Surg Am 1970;52:95-8. [Crossref] [PubMed]
- Pavel A, Smith RL, Ballard A, et al. Prophylactic antibiotics in clean orthopaedic surgery. J Bone Joint Surg Am 1974;56:777-82. [Crossref] [PubMed]
- Leaper D, Burman-Roy S, Palanca A, et al. Prevention and treatment of surgical site infection: summary of NICE guidance. BMJ 2008;337:a1924. [Crossref] [PubMed]
- Watters WC 3rd, Baisden J, Bono CM, et al. Antibiotic prophylaxis in spine surgery: an evidence-based clinical guideline for the use of prophylactic antibiotics in spine surgery. Spine J 2009;9:142-6. [Crossref] [PubMed]
- Steinberg JP, Braun BI, Hellinger WC, et al. Timing of antimicrobial prophylaxis and the risk of surgical site infections: results from the Trial to Reduce Antimicrobial Prophylaxis Errors. Ann Surg 2009;250:10-6. [Crossref] [PubMed]
- Spina NT, Aleem IS, Nassr A, et al. Surgical Site Infections in Spine Surgery: Preoperative Prevention Strategies to Minimize Risk. Global Spine J 2018;8:31S-6S. [Crossref] [PubMed]
- Blood AG, Sandoval MF, Burger E, et al. Risk and Protective Factors Associated with Surgical Infections among Spine Patients. Surg Infect (Larchmt) 2017;18:234-49. [Crossref] [PubMed]
- Olsen MA, Nepple JJ, Riew KD, et al. Risk factors for surgical site infection following orthopaedic spinal operations. J Bone Joint Surg Am 2008;90:62-9. [Crossref] [PubMed]
- Swoboda SM, Merz C, Kostuik J, et al. Does intraoperative blood loss affect antibiotic serum and tissue concentrations? Arch Surg 1996;131:1165-71; discussion 1171-2. [Crossref] [PubMed]
- Pahys JM, Pahys JR, Cho SK, et al. Methods to decrease postoperative infections following posterior cervical spine surgery. J Bone Joint Surg Am 2013;95:549-54. [Crossref] [PubMed]
- Sidhwa F, Itani KM. Skin preparation before surgery: options and evidence. Surg Infect (Larchmt) 2015;16:14-23. [Crossref] [PubMed]
- Cheng MT, Chang MC, Wang ST, et al. Efficacy of dilute betadine solution irrigation in the prevention of postoperative infection of spinal surgery. Spine (Phila Pa 1976) 2005;30:1689-93. [Crossref] [PubMed]
- Bakhsheshian J, Dahdaleh NS, Lam SK, et al. The use of vancomycin powder in modern spine surgery: systematic review and meta-analysis of the clinical evidence. World Neurosurg 2015;83:816-23. [Crossref] [PubMed]
- Evaniew N, Khan M, Drew B, et al. Intrawound vancomycin to prevent infections after spine surgery: a systematic review and meta-analysis. Eur Spine J 2015;24:533-42. [Crossref] [PubMed]
- Kang DG, Holekamp TF, Wagner SC, et al. Intrasite vancomycin powder for the prevention of surgical site infection in spine surgery: a systematic literature review. Spine J 2015;15:762-70. [Crossref] [PubMed]
- Khan NR, Thompson CJ, DeCuypere M, et al. A meta-analysis of spinal surgical site infection and vancomycin powder. J Neurosurg Spine 2014;21:974-83. [Crossref] [PubMed]
- Molinari RW, Khera OA, Molinari WJ 3rd. Prophylactic intraoperative powdered vancomycin and postoperative deep spinal wound infection: 1,512 consecutive surgical cases over a 6-year period. Eur Spine J 2012;21 Suppl 4:S476-82. [Crossref] [PubMed]
- Cheung JP, Luk KD. Complications of Anterior and Posterior Cervical Spine Surgery. Asian Spine J 2016;10:385-400. [Crossref] [PubMed]