The temporal course of mucoperiosteal flap revascularization at guided bone regeneration-treated implant sites: a pilot study.

AIMS: To investigate post-operative capillary density regeneration in healing mucoperiosteal flaps at guided bone regeneration-treated implant sites. MATERIAL AND METHODS: A non-invasive post-operative investigation was performed in 10 patients using orthogonal polarization spectral (OPS) imaging for assessment of capillary density during the course of mucoperiosteal flap wound healing for 6 weeks in patients receiving dental implants. RESULTS: The greatest increase in capillary regeneration occurred in the early wound-healing phase, during weeks 1 and 2, and recovery to baseline was achieved between weeks 4 and 5. A comparison of adjacent OPS measurements indicated that differences between the time point immediately following administration of local anaesthesia and directly post-operatively ( p=0.002), between a directly post-operative time point and after 1 week (p=0.009), and between post-operative weeks 1 and 2 (p=0.036) were statistically significant. CONCLUSIONS: The early healing phase of mucoperiosteal flaps is characterized by rapid capillary regeneration. OPS imaging enabled the possibility to monitor and quantify the temporal development of mucoperiosteal flap revascularization following periodontal surgery.

Microvascular soft tissue changes in alveolar distraction osteogenesis.

OBJECTIVE: The aim of the study was to quantify the effect of distraction osteogenesis on the changes in vascular density in the human oral mucosa. MATERIAL AND METHODS: Alveolar distraction was performed in 10 patients with alveolar ridge deficiencies, while in the contralateral nondistracted site an implant was placed. The distraction device was activated after 7 days of latency starting with a distraction rate of 1 mm a day for a 1-week period. After completion of distraction the segments were held in fixation for 6 weeks. Microvascular images were obtained with the use of orthogonal polarization spectral imaging. From day 1 postoperatively until the end of consolidation, microvascular changes in capillary density were assessed. RESULTS: All patients had a good response to the osseous distraction. No dehiscence or infections were observed. In all patients microvascular changes consisted of a bilateral decrease in capillary density and capillary index immediately following surgery. No significant differences between the distraction site and nondistracted implant site were observed during the latency phase or consolidation phase. Capillary vessel count revealed a mean of 14.6 +/- 2.7 vessels per visual field (VF) at day 5 of distraction versus 16.6 +/- 2.9 vessels/VF in the nondistracted site, which increased to a mean of 33.4 +/- 4.0 vessels/VF at day 10 of distraction compared to 24.0 +/- 0.8 vessels/VF in nondistracted implant sites. During the consolidation period the mean number of vessels was comparable to preoperative levels (mean 26.0 vessels/VF). The increase in capillary density and capillary index was more pronounced during the activation phase of distraction compared to the implant site. CONCLUSION: The increase in vascular response during distraction osteogenesis mainly occurs in the activation phase of distraction.

Cardiac resynchronization improves microcirculation.

BACKGROUND: Although it is known that cardiac resynchronization therapy (CRT) in heart failure (HF) patients improves systemic circulation, its acute effects on microcirculation are as yet unknown. Therefore we investigated the sublingual microcirculatory changes in HF patients from CRT and right ventricular (RV) pacing by use of orthogonal polarization spectral (OPS) imaging. METHODS AND RESULTS: Twelve consecutive HF patients with a CRT device and 20 healthy individuals (HI) were included. Acute microcirculatory changes were assessed by functional capillary density (FCD) and capillary velocity (CV) measurement 6 months after CRT. FCD and CV were measured in HF patients sublingually after 15 minutes of programming 1 of 3 pacing modalities in random order (no pacing, RV pacing, and CRT). FCD was significantly higher in HI (11.2 +/- 2.1 cm/cm(2)) compared with HF patients with RV pacing (8.9 +/- 1.9 cm/cm(2); P = .03) and no pacing (8.3 +/- 2.4 cm/cm(2); P = .02). CRT (12.1 +/- 2.2 cm/cm(2)) significantly increased FCD in HF patients compared with RV pacing (8.9 +/- 1.9 cm/cm(2); P = .006) and no pacing (8.3 +/- 2.4 cm/cm(2); P = .008). CV was normal in all patients with or without pacing. CONCLUSIONS: CRT improves microcirculatory function as assessed by OPS imaging.

Influence of the application of platelet-enriched plasma in oral mucosal wound healing.

PURPOSE: The aim of this study was to describe and quantify the therapeutic value of platelet concentrate on the capillary density in oral mucosal wound healing. MATERIAL AND METHODS: The subjects included 10 healthy edentulous patients who underwent bilaterally a sinus floor elevation procedure and a buccal onlay graft with autologous iliac crest bone for maxillary reconstruction. During surgery, platelet-rich plasma (PRP) was prepared from a blood sample taken from the patient. After randomization in a split-mouth design, at one side PRP was administered in the wound and at the contralateral side a placebo. At baseline, microvascular capillary density was scored with the orthogonal polarization spectral (OPS) imaging technique and repeated measurements were performed postoperatively on a daily basis until the tenth day, after which measurements were continued weekly until the fifth postoperative week. RESULTS: Ten patients, five males and five females, were included in the study with a mean age of 54.2+/-9.1 years for females and 57.6+/-6.9 years for males. Donor platelet counts from whole blood had a mean value of 248.5+/-13.5 x 10(9)/l, while the value of platelet counts in the PRP had a mean of 975.9+/-97.9 x 10(9)/l. Wound healing was significantly accelerated in the PRP-treated mucosal wounds during the first 10 postoperative days. After the second week, no obvious differences between the PRP or placebo side could be noted. CONCLUSION: PRP has a strong stimulant effect on capillary regeneration in wound healing. These effects are mainly noticeable during the early stages of wound healing.

Orthogonal polarization spectral (OPS) imaging and topographical characteristics of oral squamous cell carcinoma.

Tumor microcirculatory characteristics until now have only been assessed by histological examination of biopsies or invasive imaging technique. The recent introduction of orthogonal polarization spectral (OPS) imaging as a new tool for in vivo visualization of human microcirculation makes it possible to acquire high resolution images of the oral mucosa. In this study we report the microcirculatory changes in ten patients with oral squamous cell carcinoma of the tongue and compared the images to the normal contralateral side as the control. All carcinomas were T2 tumors without evidence for lymph node metastasis. The carcinomas were characterized by chaotic and dilated vessels accompanied by numerous areas of haemorrhage. The OPS technique seems very promising in the assessment of oral squamous cell carcinoma microcirculatory characteristics and may possibly play a future role in both the detection of early oral mucosal vascular aberrations and the effect of anti-tumor agents on the tumor microvasculature.

Quantifying bedside-derived imaging of microcirculatory abnormalities in septic patients: a prospective validation study.

INTRODUCTION: The introduction of orthogonal polarization spectral (OPS) imaging in clinical research has elucidated new perspectives on the role of microcirculatory flow abnormalities in the pathogenesis of sepsis. Essential to the process of understanding and reproducing these abnormalities is the method of quantification of flow scores. METHODS: In a consensus meeting with collaboraters from six research centres in different fields of experience with microcirculatory OPS imaging, premeditated qualifications for a simple, translucent and reproducible way of flow scoring were defined. Consecutively, a single-centre prospective observational validation study was performed in a group of 12 patients with an abdominal sepsis and a new stoma. Flow images of the microcirculation in vascular beds of the sublingual and stoma region were obtained, processed and analysed in a standardised way. We validated intra-observer and inter-observer reproducibility with kappa cross-tables for both types of microvascular beds. RESULTS: Agreement and kappa coefficients were >85% and >0.75, respectively, for interrater and intrarater variability in quantification of flow abnormalities during sepsis, in different subsets of microvascular architecture. CONCLUSION: Semi-quantitative analysis of microcirculatory flow, as described, provides a reproducible and transparent tool in clinical research to monitor and evaluate the microcirculation during sepsis.

Nitroglycerin in septic shock after intravascular volume resuscitation.

In patients with septic shock, oxygen consumption is increased, but oxygen delivery and extraction is impaired, partly because of microcirculatory shutdown and shunting. Orthogonal polarisation spectral (OPS) imaging allows visualisation of the microcirculation. We used this technique to assess microcirculatory flow in septic-shock patients who had a mean arterial blood pressure of more than 60 mm Hg and central venous pressure greater than 12 mm Hg. The infusion of 0.5 mg of nitroglycerin intravenously then resulted in a marked increase in microvascular flow on OPS imaging. Improved recruitment of the microcirculation could be a new resuscitation endpoint in septic shock.