Calculating nasoseptal flap dimensions: a cadaveric study using cone beam computed tomography.

We hypothesize that three-dimensional imaging using cone beam computed tomography (CBCT) is suitable for calculating nasoseptal flap (NSF) dimensions. To evaluate our hypothesis, we compared CBCT NSF dimensions with anatomical dissections. The NSF reach and vascularity were studied. In an anatomical study (n = 10), CBCT NSF length and surface were calculated and compared with anatomical dissections. The NSF position was evaluated by placing the NSF from the anterior sphenoid sinus wall and from the sella along the skull base towards the frontal sinus. To visualize the NSF vascularity in CBCT, the external carotic arteries were perfused with colored Iomeron. Correlations between CBCT NSFs and anatomical dissections were strongly positive (r > 0.70). The CBCT NSF surface was 19.8 cm(2) [16.6-22.3] and the left and right CBCT NSF lengths were 78.3 mm [73.2-89.5] and 77.7 mm [72.2-88.4] respectively. Covering of the anterior skull base was possible by positioning the NSF anterior to the sphenoid sinus. If the NSF was positioned from the sella along the skull base towards the frontal sinus, the NSF reached partially into the anterior ethmoidal sinuses. CBCT is a valuable technique for calculating NSF dimensions. CBCT to demonstrate septum vascularity in cadavers proved to be less suitable. The NSF reach for covering the anterior skull base depends on positioning. This study encourages preoperative planning of a customized NSF, in an attempt to spare septal mucosa. In the concept of minimal invasive surgery, accompanied by providing customized care, this can benefit the patients' postoperative complaints.

Digitally designed surgical guides for placing implants in the nasal floor of dentate patients: a series of three cases.

PURPOSE: Insight into the bone volume and position of natural teeth is essential when placing implants to retain nasal prostheses. This paper describes a series of three cases in which a new method was applied for implant placement in the nasal floor of dentate patients using digital planning techniques. MATERIALS AND METHODS: With the aid of computer software, digital planning of implants in the nasal floor based on cone beam computed tomography was performed. Next, surgical guides for implant placement were digitally designed and fabricated using rapid prototyping. RESULTS: In all three patients, implants could be placed and nasal prostheses could be manufactured as planned. All anterior teeth remained vital. Analysis of planning and post-implant placement cone beam computed tomography scans revealed high accuracy of implant placement. CONCLUSION: The applied method allows for reliable implant placement in close proximity to the preoperatively planned implant position.

Reduced aging defects in estrogen receptive brainstem nuclei in the female hamster.

UNLABELLED: The nucleus pararetroambiguus (NPRA) and the commissural nucleus of the solitary tract (NTScom) show estrogen nuclear receptor-α immunoreactivity (nuclear ER-α-IR). Both cell groups are involved in estrous cycle related adaptations. We examined in normally cycling aged hamsters the occurrence/amount/frequency of age-related degenerative changes in NPRA and NTScom during estrus and diestrus. In 2640 electron microscopy photomicrographs plasticity reflected in the ratio of axon terminal surface/dendrite surface (t/d) was morphometrically analyzed. Medial tegmental field (mtf, nuclear ER-α-IR poor), served as control. In aged animals, irrespective of nuclear ER-α-IR+ or nuclear ER-α-IR- related cell groups, extensive diffuse degenerative structural aberrations were observed. The hormonal state had a strong influence on t/d ratios in NPRA and NTScom, but not in mtf. In NPRA and NTScom, diestrous hamsters had significantly smaller t/d ratios (NPRA, 0.750 ± 0.050; NTScom, 0.900 ± 0.039) than the estrous hamsters (NPRA, 1.083 ± 0.075; NTScom, 1.204 ± 0.076). Aging affected axodendritic ratios only in mtf (p < 0.001). IN CONCLUSION: in the female hamster brain, estrous cycle-induced structural plasticity is preserved in NPRA and NTScom during aging despite the presence of diffuse age-related neurodegenerative changes.

Regional differences in age-related lipofuscin accumulation in the female hamster brainstem.

Lipofuscin accumulation is a characteristic feature of senescent postmitotic neuronal cells but estrogen may have protecting effects by inhibiting its formation. In the present ultrastructural study, lipofuscin accumulation was studied in 2 estrogen-α-receptive brainstem areas: nucleus pararetroambiguus (NPRA) and the commissural part of the solitary tract nucleus/A2 catecholaminergic group (NTScom/A2) and compared with the estrogen-insensitive medial tegmental field (mtf), in young (23 weeks) and aged (95 weeks) female hamsters. In the aged animals, extensive intracytoplasmic lipofuscin accumulation was observed. A total number of 6450 neurons were classified in 4 categories. Levels were significantly elevated in each of the brain areas studied. Lipofuscin accumulation was strongest in the mtf, less in NPRA, and remarkably less in the area of NTScom/A2. In conclusion, the observed differences in lipofuscin accumulation suggest: (1) considerable regional differences in the degree of neuronal vulnerability; and (2) a possible neuroprotective role for estrogen, because the degree of accumulation is inversely related to the density of the estrogen receptors, varying from nonreceptive (mtf) to NPRA and NTScom/A2 (most receptive).

Microvascular changes in estrogen-α sensitive brainstem structures of aging female hamsters.

Structural neuronal plasticity is present in the nucleus para-retroambiguus (NPRA) and the commissural nucleus of the solitary tract/A2 group (NTScom/A2) in female hamsters. Both brainstem nuclei play a role in estrous cycle related autonomic adaptations. We investigated how aging affects the capillary condition in these adaptive brainstem regions. Senescent female hamsters (+/-95 weeks) were tested weekly for their 4-day estrous cycle. Subsequently morphological changes of NPRA and NTScom/A2 were compared with those of young (+/-20 weeks) females in an ultrastructural study. The medial tegmental field served as control area. In 841 capillaries (n=319 capillaries, young females (N=3); n=522 capillaries, aged females (N=4)) vascular aberrations were classified into 3 categories: endothelial and tight junction, basement membrane and pericyte aberrations. In old animals, capillaries showed marked endothelial changes, disrupted tight junctions, and thickening and splitting of basement membranes. Aberrations were found in 40-60% of all capillaries. About 70% of the pericytes contained degenerative inclusions. Despite this generalized vascular degeneration, the reproductive cycle of female hamsters was unaffected by vascular senescence. Perivascular fibrosis as reported in aging rats was never observed, which suggests the existence of species differences.

Accuracy and reliability of facial soft tissue depth measurements using cone beam computer tomography.

It is important to have accurate and reliable measurements of soft tissue thickness for specific landmarks of the face and scalp when producing a facial reconstruction. In the past several methods have been created to measure facial soft tissue thickness (FSTT) in cadavers and in the living. The conventional spiral CT is mostly used to determine the FSTT but is associated with high radiation doses. The cone beam CT (CBCT) is a relatively new computer tomography system that focuses on head and neck regions and has much lower radiation doses. The aim of this study is to determine the accuracy and reliability of CBCT scans to measure the soft tissue thicknesses of the face. Seven cadaver heads were used. Eleven soft tissue landmarks were identified on each head and a punch hole was made on each landmark using a dermal biopsy punch. The seven cadaver heads were scanned in the CBCT with 0.3 and 0.4mm resolution. The FSTT at the 11 different sites (soft tissue landmarks) were measured using SimPlant-ortho volumetric software. These measurements were compared to the physical measurements. Statistical analysis for the reliability was done by means of the interclass coefficient (ICC) and the accuracy by means of the absolute error (AE) and absolute percentage error (APE). The intra-observer (0.976-0.999) and inter-observer (0.982-0.997) correlations of the CBCT and physical measurements were very high. There was no clinical significant difference between the measurements made on the CBCT images and the physical measurements. Increasing the voxel size from 0.4 to 0.3mm resulted in a slight increase of accuracy. Cone beam CT images of the face using routine scanning protocols are reliable for measuring soft tissue thickness in the facial region and give a good representation of the facial soft tissues. For more accurate data collection the 0.3mm voxel size should be considered.