Antibiotic-loaded calcium sulfate beads in spinal surgery for patients with spondylodiscitis: a clinical retrospective study

Local antibiotic carriers in the surgical management of pyogenic spondylodiscitis : First comparative evaluation of gentamicin-loaded versus vancomycin-loaded efficacy

OBJECTIVE

To evaluate the efficacy of intraoperative gentamicin versus vancomycin-loaded PerOssal (Osartis, Münster, Germany) carriers on interbody fusion rates and infection control in patients undergoing surgery for pyogenic spondylodiscitis.

METHODS

This retrospective study included 29 patients with pyogenic spondylodiscitis who underwent surgical debridement, interbody fusion, and pedicle screw fixation between February 2018 and March 2023. Patients received PerOssal carriers loaded with either gentamicin (Group A, n = 14) or vancomycin (Group B, n = 15). Clinical outcomes, including fusion rates, infection control, complications, and inflammatory markers, were analyzed.

RESULTS

Baseline characteristics between groups were comparable. Fusion rates at 3-6 months' follow-up were 92.8% (13/14) in Group A and 80.0% (12/15) in Group B, without significant differences (P > 0.05). Both groups showed significant reductions in white blood cell counts and C‑reactive protein levels postoperatively, without inter-group differences (P > 0.05). Complications included cerebrospinal fluid leakage, hematoma, pulmonary embolism, and wound infections, all managed successfully with no recurrent infections observed.

CONCLUSION

In the short term, PerOssal carriers loaded with either gentamicin or vancomycin demonstrated effective infection control for pyogenic spondylodiscitis and high interbody fusion rates. Moreover, no apparent adverse effects on bone healing were associated with the local administration of high-concentration antibiotics.

Biomechanical analysis of stabilization for thoracolumbar anterior spinal failure caused by osteolytic lesions, a finite element comparison of direct lateral corpectomy and posterior long segment instrumentation

BACKGROUND CONTEXT

Osteolytic lesions caused by infection or metastatic disease of the spine can induce instability. Different surgical strategies are available to restore stability in this scenario, however little is known how various reconstruction techniques affect spinal biomechanics.

PURPOSE

To analyze and quantify the biomechanical effects of three different surgical reconstruction techniques in the treatment of a T12 osteolytic model.

STUDY DESIGN/SETTING

Finite element analysis of the thoracic spine with a T12 osteolytic lesion.

METHODS

Using CT scans from a 20-year-old man without structural deformity, simulation of an osteolytic lesion with a 50% defect at the posterior aspect of T12 vertebral body was created by a 490 N vertical force to T9. Next, three common instrumentation techniques treating the osteolytic lesion were modeled and biomechanically tested. These included: Model A, corpectomy with short segment fixation (T11-L1) and two long-segment instrumentations; Model B long segment fixation with triple rod construct; Model C long segment fixation with dual rod construct. A load of 480N was then applied on the spine models in vertically downward direction on T9. Von Mises stresses were measured (MPa) in the discs, vertebrae, and implants.

RESULTS

Model A demonstrated the lowest stress on construct material, adjacent vertebral bodies, and discs but increased stress on the instrumented vertebrae. Model B was more rigid and demonstrated lower construct stress compared to Model C. However, Model C had the lowest vertebral body stress in flexion, extension, and lateral bending in the most upper instrumented vertebral body, but the highest screw pull-out stress when compared to Model A and Model B.

CONCLUSIONS

This osteolytic T12 model provides unique biomechanical data that can help to tailor surgical strategies in select scenarios. While optimal outcomes are best achieved with a construct tailored to a specific patient's need for stabilization, our findings can be generalized for instances of cancerous lesions, low bone density, and infectious causes.

CLINICAL RELEVANCE

The results of this study can help with the choice of appropriate surgical reconstruction technique based on patient-specific characteristics.

The effect of different antibiotic combinations in calcium sulfate cement on the growth of Cutibacterium acnes and Staphylococcus periprosthetic shoulder infection isolates

BACKGROUND

Periprosthetic joint infections (PJI) of the shoulder are a devastating complication of shoulder arthroplasty and are commonly caused by Staphylococcus and Cutibacterium acnes. Absorbable calcium sulfate (CS) beads are sometimes used for delivering antibiotics in PJI. This study evaluates the in vitro effect of different combinations of gentamicin, vancomycin, and ertapenem in beads made from CS cement on the growth of C acnes and coagulase-negative Staphylococcus (CNS) strains.

METHODS

Three strains of C acnes and 5 strains of CNS from clinically proven shoulder PJI were cultured and plated with CS beads containing combinations of vancomycin, gentamicin, and ertapenem. Plates with C acnes were incubated anaerobically while plates with Staphylococcus were incubated aerobically at 37 °C. Zones of inhibition were measured at intervals of 3 and 7 days using a modified Kirby Bauer technique, and beads were moved to plates containing freshly streaked bacteria every seventh day. This process was run in triplicate over the course of 56 days. Statistical analysis was conducted using SPSS v. 28 with repeated measures analysis of variance (ANOVA) and pairwise comparisons with Tukey correction.

RESULTS

In experiments with C acnes, beads containing ertapenem + vancomycin and vancomycin alone formed the largest zones of inhibition over time (P < .001). In experiments with Staphylococcus, beads containing vancomycin alone formed the largest zones of inhibition over time for all 5 strains (P < .001). Zones of inhibition were 1.4x larger for C acnes than for Staphylococcus with beads containing vancomycin alone. For both C acnes and Staphylococcus, beads containing ertapenem had the strongest initial effect, preventing all bacterial growth in C acnes and almost all growth for Staphylococcus during the first week but dropping substantially by the second week. Beads containing gentamicin alone consistently created smaller zones of inhibition than beads containing vancomycin alone, with vancomycin producing zones 5.3x larger than gentamicin in C acnes and 1.3x larger in Staphylococcus (P < .001).

DISCUSSION

These data suggest that for both C acnes and Staphylococcal species, CS beads impregnated with vancomycin were most effective at producing a robust antibiotic effect. Additionally, ertapenem may be a viable supplement in order to create a more potent initial antibiotic effect but is not as effective as vancomycin when used alone. Gentamicin alone was not effective in maintaining consistent and long-term antibiotic effects. These results indicate that amongst the antibiotics currently commercially available to be used with CS, vancomycin is consistently superior to gentamicin in the setting of C. acnes and CNS.

Interim Use of Antibiotic-Loaded Cement Spacer for Patients with Infected Cervical Fusion

OBJECTIVE

The management of postoperative deep infection after anterior cervical discectomy and fusion (ACDF) remains challenging for spine surgeons. Our institution uses handmade antibiotic-loaded cement spacers to treat these complex cases. This study aimed to determine the efficacy and feasibility of this treatment.

METHODS

This study included 4 patients with deep cervical spine infections after ACDF who underwent our treatment between March 2012 and January 2022. Patients' laboratory data, visual analog scale scores, comorbidities, complications, and neurological status were recorded. Their clinical conditions were also evaluated based on the Neck Disability Index, Japanese Orthopaedic Association score, and Odom criteria.

RESULTS

Infection eradication was achieved in all patients after treatment. The average preoperative visual analog scale score was 7.5 (range: 7-8); this decreased to 1.25 (range: 1-2) at 1 year postoperatively. None of the patients experienced severe complications, such as neurological deterioration or bone graft dislodgement. The Neck Disability Index improved from a preoperative value of 54% (range: 48-60%) to 6% (range: 4-8%) at 1 year postoperatively. The Japanese Orthopaedic Association score improved from a preoperative score of 10.25 (range: 10-11)-14.75 (range: 14-16) at 1 year postoperatively. All patients achieved excellent outcomes based on Odom criteria at 1 year postoperatively.

CONCLUSIONS

Good clinical outcomes were achieved in this study. Although 2-stage surgery is required, this technique could be an alternative for patients with postoperative deep infection after ACDF.

Management of Postoperative Discitis with Debridement and Novel Technique of Local Antibiotic Instillation: Functional Outcomes from a Resource-Limited Setting

BACKGROUND

Patients in low- and middle-income countries (LMICs) have substantial treatment abandonment and non-adherence with outpatient oral medications. This work sought to investigate outcomes of postoperative discitis treated with debridement and a novel technique focused on reducing outpatient antibiotic requirement in an LMIC setting.

METHODS

This study, conducted and reported following STROBE guidelines, reviewed outcomes of all patients with postoperative discitis who had been debrided by 1 neurosurgeon in a resource-limited setting during 2008-2020. Patients had undergone single-level L4-L5 or L5-S1 discectomy elsewhere, later developing magnetic resonance imaging-confirmed discitis. After non-response or deterioration following intravenous antibiotics, patients underwent early debridement, followed by in-patient antibiotic instillation into disc space for 2 weeks via drain. Study outcomes were modified Kirkaldy-Willis Grade, Japan Orthopaedic Association (JOA) score, and visual analog scale (VAS) score, all assessed at 1 year.

RESULTS

Twelve patients were included, 10 male and 2 female, with median age of 46 (IQR 3.5) years. Debridement was done after median 82.5 (IQR 35) days and took median time of 105 (IQR 17.5) minutes. VAS scores (mean ± SD) decreased from 9.25 ± 0.75 preoperatively to 0.67 ± 0.89 1 year postoperatively (mean difference 8.58, 95% CI 8.01-9.15, P < 0.001). JOA scores (mean ± SD) improved from 4.5 ± 2.94 to 26.42 ± 1.31 1 year postoperatively (mean difference 21.92, 95% CI 20.57-23.26, P < 0.001). Kirkaldy-Willis grade was excellent in 6 (50%) patients, good in 5 (41.7%), and fair in 1 (8.3%). Patients became ambulatory within 2 weeks, with no major complications during 4.15 (IQR 3.45) years of median follow-up.

CONCLUSIONS

In LMICs, patients with medically refractory postoperative discitis potentially have good outcomes after debridement plus 2-week local antibiotic instillation.

Utilization of Antibiotic Bone Cement in Spine Surgery: Pearls, Techniques, and Case Review

Vertebral osteomyelitis (VO) encompasses a spectrum of spinal infections ranging from isolated mild vertebral osteomyelitis to severe diffuse infection with associated epidural abscess and fracture. Although patients can often be treated with an initial course of intravenous antibiotics, surgery is sometimes required in patients with sepsis, spinal instability, neurological compromise, or failed medical treatment. Antibiotic bone cement (ABC) has been widely used in orthopedic extremity surgery for more than 150 years, both for prophylaxis and treatment of bacterial infection. However, relatively little literature exists regarding its utilization in spine surgery. This article describes ABC utilization in orthopedic surgery and explains the technique of ABC utilization in spine surgery. Surgeons can choose from multiple premixed ABCs with variable viscosities, setting times, and antibiotics or can mix in antibiotics to bone cements themselves. ABC can be used to fill large defects in the vertebral body or disc space or in some cases to coat instrumentation. Surgeons should be wary of complications such as ABC extravasation as well as an increased difficulty with revision. With a thorough understanding of the properties of the cement and the methods of delivery, ABC is a powerful adjunct in the treatment of spinal infections.

Vacuum assisted closure and local drug delivery systems in spinal infections: A review of current evidence

Background

Spinal infections are still showing increased incidence throughout the years as our surgical capabilities increase, coupled with an overall aging population with greater number of chronic comorbidities. The management of spinal infection is of utmost importance, due to high rates of morbidity and mortality, on top of the general difficulty in eradicating spinal infection due to the ease of hematogenous spread in the spine. We aim to summarize the utility of vacuum-assisted closure (VAC) and local drug delivery systems (LDDS) in the management of spinal infections.

Methods

A narrative review was conducted. All studies that were related to the use of VAC and LDDS in Spinal Infections were included in the study.

Results

A total of 62 studies were included in this review. We discussed the utility of VAC as a tool for the management of wounds requiring secondary closure, as well as how it is increasingly being used after primary closure as prophylaxis for surgical site infections in high-risk wounds of patients undergoing spinal surgery. The role of LDDS in spinal infections was also discussed, with preliminary studies showing good outcomes when patients were treated with various novel LDDS.

Conclusions

We have summarized and given our recommendations for the use of VAC and LDDS for spinal infections. A treatment algorithm has also been established, to act as a guide for spine surgeons to follow when tackling various spinal infections in day-to-day clinical practice.