An Analysis of Implant Retention and Antibiotic Suppression in Instrumented Spine Infections: A Preliminary Data Set of 67 Patients

Removal of Spinal Instrumentation Is Not Required to Successfully Treat Postoperative Wound Infections in Most Cases

INTRODUCTION

Controversy exists regarding whether spinal implants need to be removed to treat postoperative deep wound infections (DWIs). This retrospective study aimed to determine whether the removal or retention of implants impacts the successful treatment of a DWI after spine surgery.

METHODS

Postoperative spine surgery patients presenting with signs of infection who underwent irrigation and debridement (I&D) at Twin Cities Spine Surgeons at Abbott Northwestern Hospital, Minnesota, USA, were studied. First, the persistence of infection when implants were retained or removed was assessed. Second, we analyzed the persistence of infection with respect to the number of I&D, the use of vacuum-assisted closure (VAC) treatment, pseudoarthrosis status, and functional outcomes.

RESULTS

One hundred thirty-five patients were included. Treatment of infection with retention of implants occurred in 64% (87/135); of these, 7% (6/87) had a persistent infection. Of patients with implant removal (36%, 48/135), 6% (3/48) had a persistent infection. Thus, we observed no difference between treatment with implants present compared to implants removed (p = 1.0). Fifty of the 135 patients (37%) received I&D and primary wound closure, and 85 (63%) patients received I&D and VAC treatment. There was no statistical difference between primary wound closure and VAC treatment (p = 0.15) with respect to persistence. Repeat I&D with VAC (three or more times) had a significantly lower rate of recurrence than those with two I&Ds. Pseudoarthrosis and persistent infection were unrelated. At minimum one-year follow-up, achieving a minimum clinically important difference in functional outcome was independent of persistent infection status.

CONCLUSION

Persistent infection was unrelated to the retention of implants. When VAC treatment was deemed necessary, more than two I&Ds resulted in a significantly better cure for infection. Those with a persistent infection were no more likely to exhibit pseudoarthrosis than those with no persistent infection. All patients showed improvement in functional outcomes at minimum one-year follow-up.

Surgical Site Infection After Polymethyl Methacrylate Pedicle Screw Augmentation in Osteoporotic Spinal Vertebrae: A Series of 537 Cases

BACKGROUND

Retrospective observational study of prospectively collected outcomes.

OBJECTIVE

The use of transpedicular screws augmented with polymethyl methacrylate (PMMA) is an alternative for patients with osteoporotic vertebrae. To investigate whether using PMMA-augmented screws in patients undergoing elective instrumented spinal fusion (ISF) is correlated with an increased risk of infection and the long-term survival of these spinal implants after surgical site infection (SSI).

METHODS

We studied 537 consecutive patients who underwent ISF at some point within a 9-year period, involving a total of 2930 PMMA-augmented screws. Patients were classified into groups: (1) those whose infection was cured with irrigation, surgical debridement, and antibiotic treatment; (2) those whose infection was cured by hardware removal or replacement; and (3) those in whom treatment failed.

RESULTS

Twenty eight of the 537 patients (5.2%) developed SSI after ISF. An SSI developed after primary surgery in 19 patients (4.6%) and after revision surgery in 9 (7.25%). Eleven patients (39.3%) were infected with gram-positive bacteria, 7 (25%) with gram-negative bacteria, and 10 (35.7%) with multiple pathogens. By 2 years after surgery, infection had been cured in 23 patients (82.15%). Although there were no statistically significant differences in infection incidence between preoperative diagnoses (P = 0.178), the need to remove hardware for infection control was almost 80% lower in patients with degenerative disease. All screws were safely explanted while vertebral integrity was maintained. PMMA was not removed, and no recementing was done for new screws.

CONCLUSIONS

The success rate for treatment of deep infection after cemented spinal arthrodesis is high. Infection rate findings and the most commonly found pathogens do not differ between cemented and noncemented fusion. It does not appear that the use of PMMA in cementing vertebrae plays a pivotal role in the development of SSIs.

LEVEL OF EVIDENCE: 4

Postoperative Lumbar Spondylodiscitis Following Transforaminal Endoscopy and Outcomes of Transforaminal Lumbar Interbody Fusion

Objective: To describe the presentation spectrum of postoperative spondylodiscitis (POS<i>e</i>) following transforaminal endoscopic lumbar discectomy and to report the outcomes of transforaminal lumbar interbody fusion (TLIF).Methods: This study analyzed all patients with the classic features of POS<i>e</i> who underwent index surgery elsewhere and presented to us. They had not responded to conservative care for 3 weeks and were operated further with open TLIF. The treatment response was judged by the declining values of inflammatory markers, improvements in mobility, and decreases in pain. Patients’ outcomes were analyzed using a visual analogue scale (VAS), the Oswestry Disability Index (ODI), and the occurrence of complications. Radiological outcomes were assessed by fusion and implant stability. The spectrum of the demographic presentation was analyzed. PubMed was searched to find the incidence of POS<i>e</i> and the spectrum of organisms involved.Results: Fifteen patients were operated primarily by interventionalists and four by surgeons among 19 POS<i>e</i> patients who finally underwent TLIF at Stavya Spine Hospital & Research Institute. Organism culture positivity was found in 10 and no culture results were present in 9 cases. All TLIF cases had a follow-up of 52.94 ± 13.66 months (range, 28–71 months). The preoperative back pain VAS improved from 9.47 ± 0.61 (8–10) to 0.42 ± 0.50 (0–1). The leg pain VAS improved from 5.78 ± 4.19 (6–10) to 0.52 ± 0.61 (0–1). The preoperative ODI improved from 87.01 ± 7.70 (73.33–97.79) to 7.36 ± 8.14 (0–26.67). No major complications occurred. Cure of infection and stable reconstruction with fusion were achieved in all patients.Conclusion: POS<i>e</i> has a very low reported incidence. Standardization of training and sterilization would further reduce its incidence. However, aggressive early TLIF in patients with nonresponding POS<i>e</i> produces beneficial results.

Surgical Site Infection Management following Spinal Instrumentation Surgery: Implant Removal vs. Implant Retention: an Updated Systematical Review

Background

The number of lumbar spine surgery increased in recent years. Spinal instrumentation surgery was an integral component in the treatment of spinal pathologies, which can cause surgical site infection (SSI). Surgical site infections (SSIs) are the leading cause of mortality and morbidity after spinal instrumentation surgery. The management of SSI was implant retention and removal is still unclear.

Objective

The objective of this literature is to systematically review the implant removal and retention method for SSI management after spinal instrumentation surgery.

Methods

We searched in PubMed and ScienceDirect for cohort and randomized control trial studies in English, published between 2002 and 2022, which had data on patients with spinal instrumentation surgery. The underlying disease, comorbidities, common bacteria, type of infection, the onset of infection, implant removal, and retention percentage and recommendation were analyzed. Bias analysis using Newcastle-Ottawa Quality Assessment.

Results

We included 15 studies with a total sample were 2.584 with an average of age 15 to 66 years old. The most common organism detected were S. Aureus, MRSA, and S. Epidermis. The most common surgical procedure indications were degenerative followed by scoliosis. Implant removal and retention rate were 0-100% and 0-90,32% respectively. Implant removal is more frequently used in patients after spinal instrumentation surgery than the implant retention method.

Conclusion

Implant retention can be performed in case of SSI is < 3 months after surgery. Implant removal is recommended if the incidence of SSI is > 3 months. Empirical antibiotics therapy is necessary to reduce the possibility of implant removal after debridement. Further studies on the effect of implant removal and retention in patients on infection recurrence, pain, and quality of life of patients are needed.

Implant Retention or Removal for Management of Surgical Site Infection After Spinal Surgery

STUDY DESIGN

A literature review.

OBJECTIVE

To summarize the implant removal rate, common bacterial organisms found, time of onset, ratio of superficial to deep infection, and regurgitating the prevalence among all the retrospective and prospective studies on management and characterization of surgical site infections (SSIs).

METHODS

PubMed was searched for articles published between 2000 and 2018 on the management or characterization of SSIs after spinal surgery. Only prospective and retrospective studies were included.

RESULTS

A total of 49 articles were found relevant to the objective. These studies highlighted the importance of implant removal to avoid recurrence of SSI. The common organisms detected were methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermis, Staphylococcus epidermis, Staphylococcus aureus, and Propionibacterium acnes, with prevalence of 1% to 15%. A major proportion of all were deep SSI, with minority reporting on late-onset SSI.

CONCLUSION

Long-term antibiotics administration, and continuous irrigation and debridement were common suggestion among the authors; however, the key measure undertaken or implied by most authors to avoid risk of recurrence was removal or replacement of implants for late-onset SSI.