Bone regeneration after marginal bone resection in two-stage treatment of chronic long bone infection - a combined histopathological and clinical pilot study

Intraoperative tissue sampling for histology in chronic osteomyelitis shows high neutrophil infiltration centrally and low remains in debrided presumed infection-free regions

INTRODUCTION

Histology of debrided bone tissue is a confirmatory diagnostic criterion for fracture related infection (FRI) and prosthetic joint infection (PJI). The aim of the present study was to describe the histopathology of the first and last debrided bone tissue in chronic osteomyelitis (CO) according to the international diagnostic guidelines for FRI and PJI.

METHODS

15 patients with CO were allocated to surgical treatment using a one-stage protocol including extensive debridement. Suspected infected bone tissue eradicated early in the debridement procedure was collected as a clearly infected sample (S1). Likewise, the last eradicated bone tissue was collected as a suspected non-infected sample (S2). The samples were processed for histology. HE-stained sections were patho-morphologically examinated. Immunohistochemistry with MAC-387 antibodies towards calprotectin was used for estimation of neutrophil granulocyte (NP) score (0, 1, 2 or 3).

RESULTS

S1 samples showed a mean NP score of 2.6 (3 is confirmatory for infection). Following debridement, the NP score was significantly (p = 0.005) reduced to a mean NP score of 1.6. The S1 samples showed a mix of fibrovascular tissue, dense fibrosis, viable bone, bone necrosis and bone debris. S2 samples contained mostly viable bone tissue, however, often small fragments of necrotic bone or bone debris were present.

CONCLUSION

The inflammatory response of CO still exists after debridement, although the response fades from the center. Therefore, sampling of debrided bone tissue for histology must be performed initially during surgery, otherwise there is a risk for underestimation of NP infiltration. The present results might also be highly relevant for FRI and PJI.

Localization of osteomyelitis lesions for operative eradication of chronic osteomyelitis of the lower extremities by bone SPECT/CT: a feasibility study

PURPOSE

This study was performed to investigate the feasibility of bone single-photon emission tomography/computed tomography (SPECT/CT) for pre-operative planning of chronic osteomyelitis (COM) of the lower extremities by localization of osteomyelitis lesions.

METHODS

From January 2016 to January 2020, we surgically treated ten adult patients with Cierny-Mader type III COM in the tibia or femur for a mean duration of 24.4 months (range 7.0-70.0 months). We conducted pre-operative planning by bone SPECT/CT and localization of osteomyelitis lesions. The treatment consisted of intra-operative eradication of the infective focus and antibiotic administration. The clinical and radiological outcomes were retrospectively analyzed after a minimum of one year of follow-up.

RESULTS

The patients were surgically treated by thorough debridement, dead space management, and appropriate antibiotics without bone transport or an external fixator. The location of the hot uptake region on bone SPECT/CT coincided with that of the osteomyelitis lesion, which was confirmed intra-operatively in all patients. At an average of 16.5 ± 4.3 months (range, 13.0-25.0 months), clinical eradication of osteomyelitis was achieved in nine of the ten patients. One patient required amputation due to recurrence of osteomyelitis. A successful clinical outcome was achieved in eight patients; one suffered persistent ankle pain due to a destructive change in the ankle joint despite eradication of the infection.

CONCLUSION

Bone SPECT/CT is a feasible method for the localization and eradication of osteomyelitis lesions in COM of the lower extremities and has favourable clinical outcomes. It can also be applied in cases of distorted bony structures caused by previous trauma or surgery, or in the presence of implants.