Infections and Hardware Failure

1. Infections and Hardware Failure Colin B. Harris, MDAssistant Professor Department of Orthopaedics Rutgers – New Jersey Medical School Newark, NJ

2. Disclosures • Globus, Inc. – Consulting, teaching

3. Postoperative Surgical Site Infection (SSI) • Serious postoperative complication • Incidence • 1% non-instrumented cases • 3-12% instrumented fusions Rechtine G, et al J Orthop Trauma 2001, Glassman S et al, Spine 1996.

4. Sequelae • Pseudoarthrosis (25-50%) • Chronic wounds • Neurologic compromise / paralysis • Sepsis -> death Cahill P, Warnick D, Lee M, et al. Spine 2010;20(35):1211-17.

5. Risk Factors

6. Risk Factors

7. Risk Factors

8. Other risk factors • Use of microscope (1.4 vs 0.5%)* • Drain use • Fluoroscopy machine • Prolonged retractor use Stolke D, Sollmann WP, Seifert V. Intra- and postoperative complications in lumbar disc surgery. Spine 1989;14:56–59.

9. Preop evaluation • DM control!! HgbA1C <7.0 • Nutrition • Albumin <3.5g/dL • Total lymphocyte count <1500/mm3 • Transferrin <150 ug/dL • Weight loss • Smoking cessation Hikata T, et al. J OrthopSci 2014.

10. The basics • Do it yourself • Prep and drape (don’t delegate!) • Be mindful of OR traffic • Irrigate & reposition retractors frequently

11. Prevention • IV abx 30min prior and 24 hrs postop • 0.3% betadine irrigation + 1gm Vanco powder • Meticulous hemostasis & layered closure • Incisional wound VAC

12. Types of postoperative infection • Direct inoculation (<90 days) • Early postoperative contamination (subacute) • Hematogenous seeding (late) Mok J, Spine 2009. Cahill P, Spine 2010.

13. Organisms • S. aureus 73% (5-18% MRSA)* • S. epidermidis • E. coli, E. faecalis – fecal or genitourinary contamination • P. acnes – Low virulence, late hardware infections Pull terGunne A, Cohen D. Spine 2009;34:1422-8.

14. Diagnosis Signs/symptoms: • Wound drainage (most common) • Increasing pain • Fever • Erythema • Increased warmth Collins I, Wilson-MacDonald J, Chami G et al. Eur Spine J 2008;17:445-50.

15. Diagnosis Signs/symptoms: • Wound drainage (most common) • Increasing pain • Fever • Erythema • Increased warmth Dx can be difficult Must follow patients long-term Collins I, Wilson-MacDonald J, Chami G et al. Eur Spine J 2008;17:445-50.

16. Biological Markers • CRP: Normalize 2-3 weeks, most sensitive Takahashi J, Ebara S, Kamimura M, et al. Early-phase enhanced (18)

17. Biological Markers • CRP: Normalize 2-3 weeks, most sensitive • ESR: Peaks 2 weeks, normalizes 6 weeks Takahashi J, Ebara S, Kamimura M, et al. Early-phase enhanced (18)

18. Biological Markers • CRP: Normalize 2-3 weeks, most sensitive • ESR: Peaks 2 weeks, normalizes 6 weeks • Lymphopenia: <10% (1,000/µL) at 4 days postop sensitive for infection* Takahashi J, Ebara S, Kamimura M, et al. Early-phase enhanced (18)

19. Biological Markers • CRP: Normalize 2-3 weeks, most sensitive • ESR: Peaks 2 weeks, normalizes 6 weeks • Lymphopenia: <10% (1,000/µL) at 4 days postop sensitive for infection* • WBC count less reliable Takahashi J, Ebara S, Kamimura M, et al. Early-phase enhanced (18)

20. Imaging • Plain radiographs • Initial imaging of choice • Normal first 3-4 weeks • Halo/lysis around screws

21. Imaging • Plain radiographs • Initial imaging of choice • Normal first 3-4 weeks • Halo/lysis around screws Scrutinize carefully for subtle findings!

22. Imaging • CT • Loss of bone-implant interface • Lysis/loosening

23. Imaging • MRI • Best modality for soft tissue • Epidural / psoas abscess • Osteomyelitis

24. Instrumentation: Modes of Failure • Biologic • Infection • Osteoporosis • Other patient-related issues • Biomechanical • Error in thought process • Error in application O’ Leary P, Ghanayem A. Instrumentation Complications. In Rothman and Simeone The Spine, pp. 1777-88, Elsevier 2011.

25. Instrumentation: Modes of Failure • Biologic • Infection • Osteoporosis • Other patient-related issues • Biomechanical • Error in thought process • Error in application O’ Leary P, Ghanayem A. Instrumentation Complications. In Rothman and Simeone The Spine, pp. 1777-88, Elsevier 2011.

26. Instrumentation • Relies on interface between implant and host bone • Stability at expense of higher infection risk • Increased operative time • Glycocalyx biofilm • Titanium vs Stainless Steel

27. Principles of Treatment • Early diagnosis and treatment critical • Think of infections by chronicity and stability of spine • Act aggressively

28. Principles of Treatment • Early diagnosis and treatment critical • Think of infections by chronicity and stability of spine • Act aggressively Medical Management

29. Debridement • Systematic: Superficial to deep • Pulse lavage with NS +/- abx • Removal of loose graft material • Consider antibiotic beads

30. Debridement • Systematic: Superficial to deep • Pulse lavage with NS +/- abx • Removal of loose graft material • Consider antibiotic beads • If any doubt -> return for serial debridements until clean

31. When to remove hardware • Failed (loose/broken) instrumentation • Refractory infections • Late hematogenous infection AFTER fusion healing

32. When to remove hardware • Failed (loose/broken) instrumentation • Refractory infections • Late hematogenous infection AFTER fusion healing Implants can be retained in MOST cases of acute / subacute infections Lall R, Wong A, Lall RR, et al. J ClinNeurosci 2015;22:238-42. Khanna K, Janghala A, Sing D, et al. Int j Spine Surg 2018;12(4):490-97.

33. Re-instrumentation • Deformity progression, instability • Principles: • Be prepared to upsize screws • Go anterior (if infection posterior) • Consent to go additional levels • Iliac screws • Extension to thoracic spine Chronic antibiotic suppression may be necessary

34. 67 patient with SSI after instrumented fusion • 28% removal, 9% exchanged, 37% retained with abx • No patients with retained implants had infection recurrency at long-term follow-up

35. Wound Closure for SSI • Layered with non-braided suture • Plastic Surgery Consult-> paraspinal flaps preferred if unable to obtain tension-free closure • Multiple drains (subfascialand superficial) • Incisional wound VAC

36. Postop care • Culture-specific IV antibiotics are critical • Infectious Disease consultation • PICC line, 6-8 weeks IV abx • Follow ESR, CRP • Serial MRI -> usually not helpful

37. Case • 15 months postop T1-T6 posterior fusion-> • Treated outside facility 8 weeks IV abx, wound VAC changes • Instrumentation retained • Persistent fevers 102°F Big Problem

38. Case

39. Case

40. Case

41. SPY

43. Take-away points • Be meticulous with technique & don’t delegate

44. Take-away points • Be meticulous with technique & don’t delegate • High index of suspicion and be aggressive

45. Take-away points • Be meticulous with technique & don’t delegate • High index of suspicion and be aggressive • Safe to retain implants in most cases

46. Take-away points • Be meticulous with technique & don’t delegate • High index of suspicion and be aggressive • Safe to retain implants in most cases • Consider staged re-instrumentation • Unstable spine • Progressive deformity • Bone bone loss

47. Thank you!