Effects of buflomedil and pentoxifylline on hamster skin-flap microcirculation: prediction of flap viability using orthogonal polarization spectral imaging

Abstract

Objective: This study investigated the effects of buflomedil and pentoxifylline, both of which are used in reconstructive surgery of hamster skin flap microcirculation, and evaluated the skin flap survival rate by orthogonal polarization spectral imaging.

Method: Twenty-four adult male Syrian golden hamsters were divided into three groups: a control (C, 0.1 ml 0.9% saline), buflomedil (B, 3 mg/kg/day), and pentoxifylline group (P, 14.5 mg/kg/day). Treatments administered intraperitoneally were initiated 1 hour before skin flap preparation and continued for 7 days post-operatively at 12-hour intervals. Preparations (skin flaps) were divided into 12 fields, which were organized into six bands. Functional capillary density (FCD, in mm/mm(2)), distance from the skin flap base to blood flow cessation (Dist(with flow), in cm), percentage of viable skin (VA, in%), and qualitative analysis of blood flow by orthogonal polarization spectral imaging were performed at 1 and 24 hours and on the seventh post-operative day.

Result: Bands IV, V, and VI presented no flow independent of time. The functional capillary density group B was higher than that of groups C and P, primarily after 24 hours. All groups showed an increase in D with time but reached similar final distances (C = 2.73, B = 2.78 and P = 2.70 cm). Moreover, the percentage of viable areas remained at approximately 50%. The orthogonal polarization spectral imaging was useful to assess viability by counting fields with and without blood flow.

Conclusions: Functional capillary density values were higher in the buflomedil group compared to the control and pentoxifylline groups in this model. Functional capillary density did not influence D or the percentage of VA, and the technique showed favorable potential to assess/predict the viability of skin flaps within 1 h after surgery.

Keywords: Buflomedilm Pentoxifylline; Microcirculation; OPS; Skin flap.

Figure 1

Hamster skin flap model. Left side: the Cytoscan probe fixed by a mechanical device on the dorsal part of the animal. Right side: division of the skin flap into 12 fields from the caudal to cranial regions.

Figure 2

Dorsal skin flap of the hamster on the seventh post-operative day. The percentage of viable area was obtained by dividing the healthy area by the total area

Figure 3

The functional capillary density on bands I, II, and III among the control (C), Buflomedil (B), and Pentoxifylline (P) groups. These groups were evaluated 1 and 24 h after skin flap preparation. *p < 0.05 compared to controls

Figure 4

Distance from the skin flap base to blood flow cessation in the control, Buflomedil, and Pentoxifylline groups. These groups were evaluated 1 (Time 1h) and 24 (Time 24h) hours and 7 (Time 7d) days after skin flap preparation. *,# p < 0.05 compared to Time 1h

Figure 5

Viable skin flap area on the seventh post-operative day

Figure 6

Prediction by OPS imaging of the percentage of fields without blood flow after 1 h that persisted 7 days later