Strategies for the Prevention and Treatment of Surgical Site Infection in the Lumbar Spine

Lumbar pedicle screw pseudoarthrosis salvage technique with moldable, bioabsorbable, calcium phosphate-based putty: illustrative case

BACKGROUND

Pseudoarthrosis is a complication of spinal fixation. Risk factors include infection, larger constructs, significant medical comorbidities, and diabetes. The authors present a case report of dilated pedicle screw pseudoarthrosis salvaged with moldable, settable calcium phosphate-based putty.

OBSERVATIONS

The patient presented with back pain and radiculopathy in the setting of poorly controlled diabetes. He was taken to the operating room for laminectomy and fusion complicated by postoperative infection requiring incision and drainage. He returned to the clinic 6 months later with pseudoarthrosis of the L4 screws and adjacent segment degeneration. He was taken for revision with extension of fusion. The L4 tracts were significantly dilated. A moldable, bioabsorbable polymer-based putty containing calcium phosphate was used to augment the dilated tract after decortication back to bleeding bone, allowing good purchase of screws. The patient did well postoperatively.

LESSONS

There are several salvage options for clinically significant pseudoarthrosis after spinal fixation, including anterior or lateral constructs, extension, and revision of fusion. The authors were able to obtain good screw purchase with dilated screw tracts after addition of moldable, bioabsorbable polymer-based putty containing calcium phosphate. It appears that this may represent an effective salvage strategy for dilated pseudoarthropathy in select settings to support extension of fusion.

A SCORING SYSTEM TO PREDICT THE RISK OF SURGICAL SITE INFECTIONS AFTER SPINAL SURGERY

ABSTRACT Objective This retrospective clinical study was carried out to generate and cross-validate a scoring system for the identification of patients at risk of SSIs after spinal surgery. Methods A retrospective study was conducted, which included patients who underwent spinal surgery. The potential variables for SSIs were extracted from the database, including preoperative, intraoperative and postoperative risk factors for univariate and multivariate regression analyses. Results A total of 2347 patients were included in this retrospective clinical study. Postoperative SSIs were observed in 53 patients (2.2%). The multivariate logistic regression analysis revealed the following risk factors for SSIs after spinal surgery: diabetes mellitus ( P =0.029), body mass index ( P =0.008), low serum calcium concentration ( P =0.012), low pre- and postoperative albumin ( P =0.023, P =0.037), more than three operated segments ( P =0.008), operation time of more than 180 minutes ( P =0.019), estimated blood loss ( P =0.011), low postoperative hemoglobin ( P =0.017) and prolonged drainage time ( P =0.025). Each of these factors contributed 1 point to the risk score. The predicted rates of incidence for the low-, intermediate-, high-, and extremely high-risk categories in the validation set were 1.4%, 12%, 41.6%, and 66.6%, respectively. Conclusions Our scoring system allows for easy and validated risk stratification of SSIs after spinal surgery. Level of evidence III; Cross-sectional Observational Study.

Evaluation of effectiveness of a new treatment method for healing infected wounds: an animal model

OBJECTIVE

To evaluate the effectiveness of a new treatment method in healing superficial infected wounds compared with surgical debridement with chlorhexidine solution.

METHOD

In this animal model, two wounds were created on the back of 10 male adult rabbits. Wounds treated by Method 1 were debrided using 0.02% chlorhexidine aqueous solution and an antibiotic topical ointment. Wounds treated by Method 2 wounds were treated using a newly developed device which enabled visual monitoring of the wound as it was treated with various pharmacological solutions (including antiseptic, antiseptic oxidant and an osmotically active agent) specifically formulated for each wound healing stage. Wound area size (using digital planimetry) and time taken to clean the wound were recorded, and biopsies were taken, at the beginning of the study and at various timepoints throughout.

RESULT

It was observed that both wound cleaning and wound healing were accelerated by treatment with method 2 compared with method 1 (by 43.8% and 36.7%, respectively). There were also a significantly smaller number of complications in these wounds [p=0.0044] due to the positive ratios of neutrophils and fibroblasts in the wound cavities (from the third to the fourteenth day after wound modelling).

CONCLUSION

Wounds treated with the new device in method 2 had a shorter wound healing time than wounds treated with a traditional method. The automated influx-outflow of solutions removed any fragments of necrotic tissue from the wound surface. Wounds were able to be monitored without the need to remove dressings. The transparent, airtight film, which allowed for wound monitoring without the need to remove dressings, meant that suturing was not required. This resulted in no complications in the wounds treated by this new method.

Surgical Site Infection Prophylaxis and Wound Management in Spine Surgery

Surgical site infection (SSI) is a potentially devastating complication of spinal surgery that increases patient morbidity and healthcare costs. SSIs have complex and multifactorial etiologies; therefore, there are numerous opportunities for prevention and risk mitigation. The aim of this narrative review was to describe the incidence, risk factors, and outcomes of SSIs in spine surgery with an emphasis on postoperative wound care. We list and describe the preoperative, intraoperative, and postoperative evidence-based interventions that can be applied to potentially prevent SSI after spinal surgery.

Outcomes of surgical site infections following spinal column trauma

BACKGROUND

Surgical site infections (SSI) are an undesirable outcome of spinal surgery for both the patient and healthcare system. To date, few studies have investigated the impact of SSI on patient-reported and clinical outcomes. Sepsis and readmission are potential sequelae of SSI, with sepsis potentially being life threatening. This study aimed to assess the association between SSI and patient outcomes in a spinal trauma cohort.

METHODS

Adult (16+ years) patients who underwent emergency spinal surgery due to trauma between January 2010 and December 2016 at a major trauma centre in Melbourne, Australia, were identified through the Victorian Orthopaedic Trauma Outcomes Registry. The presence of an SSI was abstracted from the electronic medical record and outcomes were compared between patients with and without an SSI. Clinical outcomes were obtained from the medical record, and patient-reported outcomes at 6 and 12 months were obtained from the Victorian Orthopaedic Trauma Outcomes Registry. Chi-squared tests were used to compare patient outcomes between groups.

RESULTS

Of the 458 included patients, 26 (5.7%) developed an SSI. Patient-reported outcomes at 6 and 12 months were not different between the groups. An SSI was associated with sepsis (χ² ₁ = 24.20, P < 0.01), readmission (χ² ₁ = 215.34, P < 0.01), revision surgery (χ² ₁ = 171.21, P < 0.01) and removal of implants (χ² ₁ = 4.31, P = 0.04) within 12 months of discharge.

CONCLUSION

These findings indicate that spine trauma SSIs are not associated with patient-reported outcomes and may not have lasting effects on patients. Larger studies are required to assess further follow-up and support our findings and possibly distinguish outcomes between superficial and deep SSI.

Chlorhexidine Showers are Associated With a Reduction in Surgical Site Infection Following Spine Surgery: An Analysis of 4266 Consecutive Surgeries

BACKGROUND

Surgical site infection (SSI) is a common complication following spinal surgery. Prevention is critical to maintaining safe patient care and reducing additional costs associated with treatment.

OBJECTIVE

To determine the efficacy of preoperative chlorhexidine (CHG) showers on SSI rates following fusion and nonfusion spine surgery.

METHODS

A mandatory preoperative CHG shower protocol was implemented at our institution in November 2013. A cohort comparison of 4266 consecutive patients assessed differences in SSI rates for the pre- and postimplementation periods. Subgroup analysis was performed on the type of spinal surgery (eg, fusion vs nonfusion). Data represent all spine surgeries performed between April 2012 and April 2016.

RESULTS

The overall mean SSI rate was 0.4%. There was no significant difference between the pre- (0.7%) and postimplementation periods (0.2%; P = .08). Subgroup analysis stratified by procedure type showed that the SSI rate for the nonfusion patients was significantly lower in the post- (0.1%) than the preimplementation group (0.7%; P = .02). There was no significant difference between SSI rates for the pre- (0.8%) and postimplementation groups (0.3%) for the fusion cohort (P = .21). In multivariate analysis, the implementation of preoperative CHG showers were associated with significantly decreased odds of SSI (odds ratio = 0.15, 95% confidence interval [0.03-0.55], P < .01).

CONCLUSION

This is the largest study investigating the efficacy of preoperative CHG showers on SSI following spinal surgery. In adjusted multivariate analysis, CHG showering was associated with a significant decrease in SSI following spinal surgery.

Current Strategies for Reconstruction of Soft Tissue Defects of the Spine

Spinal surgery has been revolutionized by advances in instrumentation, bone graft substitutes, and perioperative care. Extensive dissection, creation of large areas of dead space, and the use of instrumentation in compromised patients, however, predisposes to high rates of wound complications. Postoperative wound complications in patients undergoing complex spinal surgery can have devastating sequelae, including hardware exposure, meningitis, and unplanned reoperation. Recognition of high-risk patients and prediction of wound closure difficulties, combined with preemptive reconstructive surgical strategies may prevent complications. The purpose of this review is to discuss the principles of spine wound management and provide a synopsis of the soft tissue reconstructive strategies utilized in spinal surgery. We review the senior author's preferred reconstructive algorithm for the management of these complex wounds, in addition to outcomes data relating to the timing of reconstructive surgery.