PMMA-Cement-PLIF Is Safe and Effective as a Single-Stage Posterior Procedure in Treating Pyogenic Erosive Lumbar Spondylodiscitis-A Single-Center Retrospective Study of 73 Cases

Abstract

Background: Surgical treatment for erosive pyogenic spondylodiscitis of the lumbar spine is challenging as, following debridement of the intervertebral and bony abscess, a large and irregular defect is created. Sufficient defect reconstruction with conventional implants using a posterior approach is often impossible. Therefore, we developed the "Cement-PLIF", a single-stage posterior lumbar procedure, combining posterior lumbar interbody fusion (PLIF) with defect-filling using antibiotic-loaded polymethylmethacrylate (PMMA). This study first describes and evaluates the procedure's efficacy, safety, and infection eradication rate. Radiological implant stability, bone-regeneration, sagittal profile reconstruction, procedure-related complications, and pre-existing comorbidities were further analyzed.

Methods: A retrospective cohort study analyzing 73 consecutive patients with a minimum of a one-year follow-up from 2000-2017. Patient-reported pain levels and improvement in infectious serological parameters evaluated the clinical outcome. Sagittal profile reconstruction, anterior bone-regeneration, and posterior fusion were analyzed in a.p. and lateral radiographs. A Kaplan-Meier analysis was used to determine the impact of pre-existing comorbidities on mortality. Pre-existing comorbidities were quantified using the Charlson-Comorbidity Index (CCI).

Results: Mean follow-up was 3.3 (range: 1-16; ±3.2) years. There was no evidence of infection persistence in all patients at the one-year follow-up. One patient underwent revision surgery for early local infection recurrence (1.4%). Five (6.9%) patients required an early secondary intervention at the same level due to minor complications. Radiological follow-up revealed implant stability in 70/73 (95.9%) cases. Successful sagittal reconstruction was demonstrated in all patients (p < 0.001). There was a significant correlation between Kaplan-Meier survival and the number of pre-existing comorbidities (24-months-survival: CCI ≤ 3: 100%; CCI ≥ 3: 84.6%; p = 0.005).

Conclusions: The Cement-PLIF procedure for pyogenic erosive spondylodiscitis is an effective and safe treatment as evaluated by infection elimination, clinical outcome, restoration, and maintenance of stability and sagittal alignment.

Keywords: PMMA; bony erosion; discitis; osteomyelitis; polymethylmethacrylate; spinal implants; spinal infection; spine; spondylodiscitis; staphylococcus aureus.

Figure 1

The in-house treatment algorithm for lumbar spondylodiscitis is illustrated. This study focused on the third group, marked with inverted colors, italic characters, and grey boxes.

Figure 2

Patient cohort selection diagram.

Figure 3

Thirty-eight-year-old male patient suffering from severe erosive spondylodiscitis with a ~40% bony defect in L3/4. Preoperative MRI and CT scans are shown in images (a,b). Immediately postoperatively (c) and one-year postoperatively (d) lateral and (e) a.p. X-rays show bony regeneration and clinical infection consolidation in the affected segment L3/4. L5 was included in the stabilization due to a weak bony situation during the operation to provide sufficient stability.

Figure 4

Initial X-ray shows a retrolisthesis L2/3 with mild segmental degeneration in a sixty-two-year-old male patient (a). Follow-up MRI due to persistent pain six weeks later shows pyogenic spondylodiscitis in L2/3 with progressive bony destruction (b). Directly postoperative (c) and 12 months (d,e) postoperative a.p. and lateral radiographs with anterior PMMA leakage, bone regeneration, and stable implants.

Figure 5

Female patient, 46-years old, pyogenic erosive spondylodiscitis L4/5 with staphylococcus aureus identified as the causative pathogen. Preoperative standing a.p. and lateral X-ray (a), MRI of the lumbar spine (b), and CT scan (c). Postoperative standing a.p. and lateral X-ray after Cement-PLIF L4/5 and postero-lateral fusion (d). Six-year follow-up with standing X-rays a.p. and lateral of the lumbar spine (e). Cranial adjacent segment disease (L3/4) is demonstrated by MRI (f). Adjacent segment fixation L3/4 after preoperative exclusion of reinfection by open biopsy with postoperative standing X-rays of the lumbar spine six years post-operatively (g). Sixteen-year follow-up CT scan of the lumbar spine with intact Cement-PLIF, anterior and posterior fusion, and infection elimination (h).

Figure 5

Female patient, 46-years old, pyogenic erosive spondylodiscitis L4/5 with staphylococcus aureus identified as the causative pathogen. Preoperative standing a.p. and lateral X-ray (a), MRI of the lumbar spine (b), and CT scan (c). Postoperative standing a.p. and lateral X-ray after Cement-PLIF L4/5 and postero-lateral fusion (d). Six-year follow-up with standing X-rays a.p. and lateral of the lumbar spine (e). Cranial adjacent segment disease (L3/4) is demonstrated by MRI (f). Adjacent segment fixation L3/4 after preoperative exclusion of reinfection by open biopsy with postoperative standing X-rays of the lumbar spine six years post-operatively (g). Sixteen-year follow-up CT scan of the lumbar spine with intact Cement-PLIF, anterior and posterior fusion, and infection elimination (h).

Figure 6

Sixty-two-year-old male patient with severe destructive spondylodiscitis L4/5. Preoperative CT-Scheme and lateral X-ray (a,b). Three-month follow-up radiograph (c,d). X-ray and CT scan one year after surgery showing anterior, intervertebral pseudarthrosis with stable posterior implants (e–h).

Figure 7

Kaplan–Meier survival curves for all patients (a) and differentiated by comorbidities determined with a median split of the CCI: CCI ≤ 3; n = 36 (blue graph) and >3; n = 37 (red graph), log-rank test: p = 0.005 (b).

Figure 7

Kaplan–Meier survival curves for all patients (a) and differentiated by comorbidities determined with a median split of the CCI: CCI ≤ 3; n = 36 (blue graph) and >3; n = 37 (red graph), log-rank test: p = 0.005 (b).