gms | German Medical Science

Introduction: Fluorescence microscopy is an innovative tool for the intraoperative evaluation of perfusion in soft tissue structures and chronic inflammatory processes in bone structures. In secondary neurosurgical interventions wound closure is highly endangered by the disturbance of tissue perfusion in scar tissue. If bone sequestration occurs, this method can be supplemented by additional fluorescence microscopy within the range of 400nm.

Material and methods: ICG fluorescence microscopy was applied to three patients (0,3 mg /kg) in the range of 800nm and 400nm (OPMI Pentero, Zeiss). For the infrared video angiography ICG was administered intravenously and the following dynamic tissue perfusion was investigated during the arterial, capillary and venous phase.

Patient 1: explantation of the bone flap due to osteonecrosis and implantation of an individual plastic. Explantation with wound dehiscence, decrease of tissue perfusion in wound margin, implantation of an expander, incision planning with ICG and new skull plastic

Patient 2, craniocervical stabilisation (CerviFix), chronic inflammation process and progressive dehiscence of occiput with exposed osteosynthesis material

Patient 3: titanium implant temporo-occipital, progressive inflammation process of skin and bone in spite of antibiotic treatment

Results: In the first two cases the perfusion of the galea was evaluated and a sufficient wound closure was achieved. Patient 1 intraoperatively showed decreased tissue perfusion under the application of ICG which was macroscopicly inconspicuous (Figure 1 [Fig. 1]). After removal sufficient wound closure was achieved. The combined application of fluorescence in the range of 800nm and 400nm in the third case allowed a reliable distinction between vital and necrotic bone.

Conclusion: Fluorescence microscopy enables the intraoperative diagnosis of tissue perfusion as well as the distinction between vital and necrotic bone structures. Thus it’s essential for the planning, for intraoperative decision making and for the control of results in all interventions with critical tissue perfusion.