Debridement effectiveness of infected bone tissue of chronic hematogenous osteomyelitis in the lower extremities under the guidance of 99mTc-MDP SPECT/CT fused images / 中华创伤杂志

ABSTRACT

Objective:To explore the debridement effectiveness of infected bone tissue of chronic hematogenous osteomyelitis in the lower extremities under the guidance of 99mTc-MDP SPECT/CT fused images. Methods:A retrospective case series analysis was conducted on 21 patients with chronic hematogenous osteomyelitis in the lower extremities treated at Southwest Hospital of Army Medical University from May 2017 to June 2020. There were 8 males and 13 females, with the age range of 10-62 years [23(18, 37)years]. The tibial infections were found in 16 patients, and femoral infections in 5 patients. The duration of bone infection was 4-480 months [120(42, 228)months]. According to the Cierny-Mader anatomico-physiological system, 4 patients were classified as type I, 14 as type III, 3 as type IV; 18 patients were classified as type A and 3 as type B. Intraoperative debridement of infected bone tissue was operated at stage I on the region of interest (ROI) where the isocontour(ISO) value was between 30%-40%, using the preoperative 99mTc-MDP SPECT/CT fused images as the reference. The stage II bone defect reconstruction was based on autologous and / or allogeneic bone. To observe the frequency of operations regarding bone infection control in stage I. The preoperative white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), intraoperative bacterial culture and pathological examination were compared at stages I and II. The skin redness and swellings, pain, sinus tract in the infected limbs, and ossification of grafted bones in the original bone defect part were observed at stage II. The accuracy rate between ISO value in the region of interest (ROI) and set ISO figure was checked. The difference of longitudinal length of the bone debridement area in ROI area with the actual bone debridement area was observed under the coronal position. Results:All patients were followed up for 6-36 months [11(9, 29)months] after stage II operation. All of the 21 patients had undergone operations of infection control with an average number of 1.04 times in stage I. 1 patient's intraoperative frozen section indicated that neutrophils were>5/HP. The bone graft at stage II had been completed after another debridement. Comparison of preoperative inflammatory markers at stages I and II: the WBC was decreased from (5.9±1.6)×10 9/L to (5.4±1.5)×10 9/L ( P>0.05), the ESR decreased from 9(5, 26)mm/h to 4(2, 10)mm/h ( P<0.05), and the CRP decreased from 2.8(2.3, 7.7)mg/L to 2.3(1.4, 3.0)mg/L ( P>0.05). The results of bacterial culture of tissue at stage I were positive in 12 patients and negative in 9 patients. The pathological examination indicated neutrophils and lymphocyte infiltration. The results of bacterial culture of tissue at stage II were all negative. A modicum of plasmacyte and lymphocyte infiltration and the neutrophils (<5 per/Hp) had been found in the intraoperative frozen section and pathological examination. No redness, swelling or sinus tract was found in the skin after stage II surgery and ossification of grafted bone was good. The accuracy rate between ISO value in the ROI and set ISO figure was 90.5%. The comparison between longitudinal debridement scope of ROI [(86.8±31.1)mm] and actual bone tissue debridement scope [(86.0±31.3)mm] at stage I showed no significant difference ( P>0.05). Conclusions:99mTc-MDP SPECT/CT fused images can be used as an effective means to define the debridement scope of infected bone tissue preoperatively. The method can not only avoid excessive debridement, but also improve the cure rate of hematogenous osteomyelitis in the lower extremities.