The impact of hyperbaric oxygen therapy on late irradiation injury in oral microcirculation.

BACKGROUND: Late side effects of radiotherapy in patients with head and neck cancer (HNCPs) result in decreased tissue vascularity, a compromised healing capacity and spontaneous breakdown of tissue. The aim of this study was to examine the in vivo effect of hyperbaric oxygen therapy (HBOT) on the microcirculation in irradiated oral tissue. METHODS: Using a handheld microscope, the effect of HBOT on oral mucosal microcirculation parameters was measured in 34 previously irradiated HNCPs prior to HBOT and at 4 weeks and 6 months posttreatment. RESULTS: A significant increase in mean buccal vessel density and decrease in buccal vessel diameter was found 6 months after HBOT compared to baseline, 22 ± 11 versus 25 ± 7 cpll/mm2 (p < 0.05) and 20 ± 4 versus 16 ± 5 µm (p < 0.05), respectively. CONCLUSION: Our results indicate that oral microcirculation histopathology associated with irradiation is able to respond to HBOT by redirecting oral microcirculation parameters towards values consistent with healthy tissue.

Minimally Invasive Treatment With a Patient Specific Implant in Reconstruction of Isolated Anterior Wall Fracture of the Frontal Sinus.

ABSTRACT: Isolated fractures of the anterior wall of the frontal sinus are most often treated through a coronal approach. Although the coronal approach is a relatively easy procedure, the size of the incision is causing more problems related to patient morbidity and recovery time than smaller approaches. A novel, minimal invasive procedure for reconstruction of the anterior wall fracture of the frontal sinus is presented in this article. An endoscopic assisted approach to camouflage the defect of the anterior wall and restore the contour of the frontal bone with a titanium patient specific implant is described in 2 patients. The aim of this procedure is to evaluate the effect on the operating time, recovery time, length of hospital stay and facial scarring compared to the conventional coronal approach. Postoperative evaluation was performed by superimposing pre and postoperative 3D stereophotographs and computed tomography scans. A distance map demonstrated an accurate reconstruction of the preoperatively planned contour. Postoperative recovery of both patients was quick and uneventful with no complications. The use of endoscopically inserted patient specific implant for contour reconstruction in anterior wall fractures of the frontal sinus seems to offer a predictable and minimal invasive alternative to the conventional approach.

Patient-Side Appraisal of Late Radiation-Induced Oral Microvascular Changes.

PURPOSE: To determine the clinical feasibility of examining and measuring late irradiation changes in the oral microcirculation of head and neck (HN) cancer patients using the novel CytoCam video microscope system. METHODS AND MATERIALS: In 30 HN cancer patients and 30 age-matched controls, bilateral video images were recorded noninvasively of the oral microcirculation of the buccal mucosa and mandibular gingiva. Tissue perfusion parameters, such as functional capillary density (FCD), buccal blood vessel diameter, and microcirculatory flow index, were analyzed. RESULTS: No difference was observed for mean buccal mucosa FCD in irradiated versus healthy tissue, whereas a lower mean gingival FCD in irradiated versus healthy tissue was observed (34 ± 17 capillaries per millimeter squared [cpll/mm2] vs 68 ± 19 cpll/mm2; P < .001). A significant difference in mean buccal blood vessel diameter of 16 ± 3 µm was measured, compared with 14 ± 1 µm in control buccal mucosa (P < .001). No significant difference in microcirculatory flow index was observed between the 2 groups. CONCLUSIONS: Quantifying oral microcirculatory injury associated with late irradiation effects using the CytoCam was feasible in HN cancer patients. Results indicate that marked differences in tissue-specific microcirculatory measurements of angioarchitecture, diminished capillary density, and extensively dilated blood vessel diameters are associated with late irradiation effects in HN cancer patients.

Sublingual microvascular perfusion is altered during normobaric and hyperbaric hyperoxia.

Hyperoxia and hyperbaric oxygen therapy can restore oxygen tensions in tissues distressed by ischemic injury and poor vascularization and is believed to also yield angiogenesis and regulate tissue perfusion. The aim of this study was to develop a model in which hyperoxia-driven microvascular changes could be quantified and to test the hypothesis that microcirculatory responses to both normobaric (NB) and hyperbaric (HB) hyperoxic maneuvers are reversible. Sublingual mucosa microcirculation vessel density, proportion of perfused vessels, vessel diameters, microvascular flow index, macrohemodynamic, and blood gas parameters were examined in male rabbits breathing sequential O2/air mixtures of 21%, 55%, 100%, and return to 21% during NB (1.0 bar) and HB (2.5 bar) conditions. The results indicate that NB hyperoxia (55% and 100%) produced significant decreases in microvascular density and vascular diameters (p<0.01 and p<0.05, respectively) accompanied by significant increases in systolic and mean arterial blood pressure (p<0.05, respectively) with no changes in blood flow indices when compared to NB normoxia. HB normoxia/hyperoxia resulted in significant decreases in microvascular density (p<0.05), a transient rise in systolic blood pressure at 55% (p<0.01), and no changes in blood vessel diameter and blood flow indices when compared to NB hyperoxia. All microcirculation parameters reverted back to normal values upon return to NB normoxia. We conclude that NB/HB hyperoxia-driven changes elicit reversible physiological control of sublingual mucosa blood perfusion in the presence of steady cardiovascular function and that the absence of microvascular vasoconstriction during HB conditions suggests a beneficial mechanism associated with maintaining peak tissue perfusion states.

Hyperbaric oxygen therapy accelerates vascularization in keratinized oral mucosal surgical flaps.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) is thought to promote vascular regeneration in wounds. The purpose of this study was to investigate the role of HBOT in advancing vascular regeneration in healing oral mucosal surgical flaps. METHODS: A palatine partial-thickness mucosal flap was raised in 10 male-specific pathogen-free New Zealand White rabbits. Randomized into 2 groups of 5 animals each (control and HBOT), functional capillary density was measured preoperatively (baseline), and immediately postoperatively until day 21 using sidestream dark-field video microscopy. Ten HBOT sessions were administered over the course of 2 weeks at 2.5 atmospheres (2.5 bar O2 /90 minutes). RESULTS: Repeated measures analysis of variance was used to compare the HBOT and control group on the sequential functional capillary density measurements. A significant interaction effect was present between time and group (F [8, 64] = 9.60; p < .0001) resulting from a significant increase in microcirculation in the HBOT group relative to the control group on days 7, 9, and 11. CONCLUSION: Our results suggest that HBOT is capable of advancing wound vascular regeneration in healing keratinized oral mucosal flaps.