In the JournalsPerspectiveFrom OT Europe

Implant infection after spinal fusion correlated with pedicle screw loosening, ongoing pain

Investigators found implant infections are correlated with pedicle screw loosening and ongoing pain that can lead to the need for revision surgery after spinal fusion.

Researchers identified 110 who underwent revision surgery after an open spinal fusion with metal explantation from thoracic and lumbar spine. Investigators performed an intraoperative infection screening from wound and explanted material sonication during the revision surgery after dorsal stabilization. Independent factors of pedicle screw loosening were identified with multivariate logistic regression analysis.

Results from the infection screening identified a Staphylococcus and Propionibacterium genus germ in 29.1% of the revision cases. A significantly higher number of previous spinal surgeries and radiographic pedicle screw loosening was seen in patients who screened positive. A significantly lower rate of positive infection screening was seen in patients who were revised for adjacent segment failure compared with those who were revised for directly implant related reasons. Investigators noted implant removal showed positive screening at revision surgery led to significant pain relief 1-year postoperatively.

“As clinical presentation of chronic infection is very unspecific prior to revision surgery of failed spinal fusion, radiographic screw loosening characteristics and multiple prior operations should be suspicious for deep implant infection,” the investigators wrote. “Based on our data, we recommend evaluation for implant removal in spinal fusion cases with chronic, unspecific back pain especially when radiologic loosening signs are present.” – by Monica Jaramillo

 

Disclosures: The authors report no relevant financial disclosures.

Investigators found implant infections are correlated with pedicle screw loosening and ongoing pain that can lead to the need for revision surgery after spinal fusion.

Researchers identified 110 who underwent revision surgery after an open spinal fusion with metal explantation from thoracic and lumbar spine. Investigators performed an intraoperative infection screening from wound and explanted material sonication during the revision surgery after dorsal stabilization. Independent factors of pedicle screw loosening were identified with multivariate logistic regression analysis.

Results from the infection screening identified a Staphylococcus and Propionibacterium genus germ in 29.1% of the revision cases. A significantly higher number of previous spinal surgeries and radiographic pedicle screw loosening was seen in patients who screened positive. A significantly lower rate of positive infection screening was seen in patients who were revised for adjacent segment failure compared with those who were revised for directly implant related reasons. Investigators noted implant removal showed positive screening at revision surgery led to significant pain relief 1-year postoperatively.

“As clinical presentation of chronic infection is very unspecific prior to revision surgery of failed spinal fusion, radiographic screw loosening characteristics and multiple prior operations should be suspicious for deep implant infection,” the investigators wrote. “Based on our data, we recommend evaluation for implant removal in spinal fusion cases with chronic, unspecific back pain especially when radiologic loosening signs are present.” – by Monica Jaramillo

 

Disclosures: The authors report no relevant financial disclosures.

    Perspective
    Aakash Agarwal

    Aakash Agarwal

    This article revealed a previously unknown mode of implant failure after spine surgery. The investigation of the prevalence of chronic deep implant infection in patients revised for pain after spinal fusion is substantial. This, when combined with available evidence from Agarwal, et al, supports the researchers’ theory behind the cause of implant failure, that there is “a hidden prevalence of sub-clinical germ colonization on the implant could be an underlying mechanism in [pedicle screw] PS loosening.” As demonstrated in results of the two-staged approach to this research, the pedicle screws are being contaminated in two phases: preoperative phase and intraoperative phase, both of which could be mitigated by employing newer methodologies or standards of care.

    References:

    Agarwal A, et al. e-Poster 28. Presented at: Safety in Spine Surgery Summit; April 20, 2018; New York.

    Agarwal A, et al. Global Spine Journal. 2018;doi.org/10.1177/2192568218762380.

    Agarwal A, et al. Global Spine Journal. 2018;doi.org/10.1177/2192568218784298.

    Agarwal A., et al. Global Spine Journal. 2018; doi.org/10.1177/2192568218780676.

    Agarwal A, et al. Paper 53. Presented at: Society for Minimally Invasive Spine Surgery Annual Meeting; Sept. 6-8, 2018; Las Vegas.

    Agarwal, A. et al. Reducing bacterial dose during instrumented spine surgery: A clinical study on a novel and effortless Method; Presented at: North American Spine Society Annual Meeting; Sept. 26-29, 2018; Los Angeles.

    • Aakash Agarwal, PhD
    • Director of research & development
      Spinal Balance Inc.
      Toledo, Ohio

    Disclosures: Agarwal reports no relevant financial disclosures.