The X-Ray Shows Instrumentation Failure-What I Do Christopher Brown M.D. Duke University
Disclosure • NuVasive: – Royalties – Consulting – Fellowship Support
Classification of Complications • Biologic Failure related to: – Infection – Pseudarthrosis • Biomechanical Failure • Error in thought process • Error in application
Early Hardware Failure • HPI: 70 y/o male with bilateral LE leg pain for greater than 2 years, failed conservative treatment. Initially had a good response to ESI.
• L4/L5 Lateral interbody fusion, L5/S1 ALIF, L4-S1 Posterior spinal fusion • Post operatively had complete resolution of his lower extremity complaints • Discharged to home POD # 2
• 4 weeks post op was admitted with acute onset back pain and bilateral lower extremity complaints. – Afebrile, WBC 10.5, CRP 1.82, SED Rate: 78 • MRI: • CT: L4-L5 cage subsidence, loosening of right L4 screw
Spinal Infection • Up to 2.8-6% of instrumented cases (1,2,3). • Risk factors: – DM, Smoking, previous spine surgery, obesity, malnutrition, immunocompromised, corticosteroids (4, 5, 6). • Three potential sources for infection: – Direct inoculation – Contaminated during early postoperative period – Hematogenous seeding (7, 8, 9) . • Gram positive organism account for more than 50% of infections: – Staph aureus (most common), staph epidermidis (2, 10, 11). – Infections that present greater than 1 year are generally caused by low-verulence organisms such as coagulase-negative staph and propionibacterium (9, 12).
Clinical Presentation • Most common presenting symptom is pain. • Generally have an interval pain free period immediately following surgery and then develop increasing pain (13) . • Fever is the most common constitutional symptoms however, many patients with deep infection will have no systemic symptoms (13).
Laboratory Testing • WBC with differential, ESR, CRP • ESR should normalize following surgery in 3- 6 wks (14, 15). • CRP levels generally peak on post operative day three and return to baseline by 10-14 days (15, 16). • Blood cultures should be obtained. • The most accurate cultures are those obtained during surgical debridement (13).
Imaging • Plain radiographs typically require 4 weeks to pass until evidence of infection is evident (17). • CT allows for earlier detection. Evaluate for endplate changes, bony lysis and or soft tissue fluid collection (13). • MRI with and without gadolinium is the most effective imaging technique available. – The most reliable finding consentient with early infection is increased signal intensity of the adjacent vertebral body on T1 weighted images (58).
Management • The ultimate goal is eradication of the infection • Surgical debridement should consist of excision of all infected dermal margins and subcutaneous layer with exploration of the deep fascia (13).
Management • After specimens for culture have been obtained broad spectrum antibiotics are started. • Bone graft that is infected or loosened should be removed (19,20,21,22).
Management • Instrumentation should be routinely inspected. Implants with obvious signs of loosening should be removed (13). • Well fixed instrumentations can remain (28,29, 30, 31, 32, 33). • Ideally instrumentation is maintained until fusion occurs (13).
• Pt underwent I and D with revision of L4-L5 lateral interbody cage with extension of posterior fusion to L3. • Cultures + pan-sensitive Proprionibacterium • Treated with 6 weeks IV antibiotics
Late Failure • 70 y/o males s/p previous L4-L5 posterior lateral fusion. Initially did well then had worsening back and leg pain.
• MRI showed bilateral foraminal stenosis at L4-L5 and L5-S1
• CT lumbar spine showed Lucency around the L4 and L5 screws
Pseudarthrosis • Rate of pseudarthrosis after lumbar fusion is between 5% and 35% (33, 34, 35, 36). • Pseudarthrosis is defined by a complete absence of continuous trabeculation between adjacent vertebrae, implant radiolucency, and or motion on dynamic films (37,38,39). • US FDA’s define successful fusion as less than 3 mm of translation and less than 5 degrees of angular motion on flexion and extension.
Imaging • Plain radiographs have a high false negative rate (a11) and have a limited ability to show pseudarthrosis in the first 2-3.5 years (40, 42). • CT has become the modality of choice for diagnosing pseudarthrosis (42). – At 12 months a radiolucent zone of greater than 1 mm has shown to be an early predictor of pseudarthrosis (43).
Treatment • 360 fusion has been shown to have the highest fusion rates (44). • ALIF has the added advantage of avoiding midline scar formation (45)
• Pt underwent revision lumbar fusion • Removal of hardware, L3-L5 Lateral interbody fusion, L5-S1 anterior interbody fusion, with posterior instrumented fusion L3-S1
Biomechanical failure Sagittal Balance • 68 yo 12 months post op • Intractable back and leg pain • Normal exam • Normal infectious labs
Asymptomatic Hardware Failure • 75 yo eight years after lumbar fusion • No complaints of back or leg pain
References 1. Rechtine GR, Bono PL, Cahill D, et al: Postoperative wound infection after instrumentation of thoracic and lumbar fractures. J Orthop Trauma 2001; 15: pp. 566-569 2. Massie JB, Heller JG, Abitbol JJ, et al: Postoperative posterior spinal wound infections. Clin Orthop Relat Res 1992; 284: pp. 99-108 3. Hodges SD, Humphreys SC, Eck JC, et al: Low postoperative infection rates with instrumented lumbar fusion. South Med J 1998; 91: pp. 1132- 1136 4. aa 5. Cruse PJ, and Foord R: The epidemiology of wound infection. A v10-year prospective study of 62,939 wounds. Surg Clin North Am 1980; 60: pp. 27-40 6. Mishriki SF, Law DJ, and Jeffery PJ: Factors affecting the incidence of postoperative wound infection. J Hosp Infect 1990; 16: pp. 223-230 7. Sponseller PD, LaPorte DM, Hungerford MW, et al: Deep wound infections after neuromuscular scoliosis surgery: a multicenter study of risk factors and treatment outcomes. Spine 2000; 25: pp. 2461-2466 8. de Jonge T, Slullitel H, Dubousset J, Miladi L, Wicart P, and Illes T: Late-onset spinal deformities in children treated by laminectomy and radiation therapy for malignant tumours. Eur Spine J 2005; 14: pp. 765-771 9. Heggeness MH, Esses SI, Errico T, and Yuan HA: Late infection of spinal instrumentation by hematogenous seeding. Spine 1993; 18: pp. 492- 496 10. Zeidman SM, Ducker TB, and Raycroft J: Trends and complications in cervical spine surgery:1989-1993. J Spinal Disord 1997; 10: pp. 523-526 11. Wimmer C, Gluch H, Franzreb M, and Ogon M: Predisposing factors for infection in spine surgery: a survey of 850 spinal procedures. J Spinal Disord 1998; 11: pp. 124-128 12. Weinstein MA, McCabe JP, and Cammisa FP: Postoperative spinal wound infection: a review of 2,391 consecutive index procedures. J Spinal Disord 2000; 13: pp. 422-426 13. Book 14. Kapp JP, and Sybers WA: Erythrocyte sedimentation rate following uncomplicated lumbar disc operations. Surg Neurol 1979; 12: pp. 329-330 15. Thelander U, and Larsson S: Quantitation of C-reactive protein levels and erythrocyte sedimentation rate after spinal surgery. Spine 1992; 17: pp. 400-404 16. Fouquet B, Goupille P, Jattiot F, et al: Discitis after lumbar disc surgery. Features of “aseptic” and “septic” forms. Spine 1992; 17: pp. 356-358 17. Silber JS, Anderson DG, Vaccaro AR, et al: Management of postprocedural discitis. Spine J 2002; 2: pp. 279-287 18. Boden SD, Davis DO, Dina TS, et al: Postoperative diskitis: distinguishing early MR imaging findings from normal postoperative disk space changes. Radiology 1992; 184: pp. 765-771 19. Richards BR, and Emara KM: Delayed infections after posterior TSRH spinal instrumentation for idiopathic scoliosis: revisited. Spine 2001; 26: pp. 1990-1996 20. Li YZ: [Wound infection after spinal surgery: analysis of 15 cases]. Zhonghua Wai Ke Za Zhi 1991; 29: pp. 484-486
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