| 1. |
- Agosti, Edoardo, et al.
(author)
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Quantitative Anatomic Comparison of Endoscopic Transnasal and Microsurgical Transcranial Approaches to the Anterior Cranial Fossa
- 2022
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In: Operative Neurosurgery. - : Congress of Neurological Surgeons. - 2332-4252 .- 2332-4260. ; 23:4, s. e256-e266
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Journal article (peer-reviewed)abstract
- BACKGROUND: Several microsurgical transcranial approaches (MTAs) and endoscopic transnasal approaches (EEAs) to the anterior cranial fossa (ACF) have been described.OBJECTIVE: To provide a preclinical, quantitative, anatomic, comparative analysis of surgical approaches to the ACF.METHODS: Five alcohol-fixed specimens underwent high-resolution computed tomography. The following approaches were performed on each specimen: EEAs (transcribriform, transtuberculum, and transplanum), anterior MTAs (transfrontal sinus interhemispheric, frontobasal interhemispheric, and subfrontal with unilateral and bilateral frontal craniotomy), and anterolateral MTAs (supraorbital, minipterional, pterional, and frontotemporal orbitozygomatic approach). An optic neuronavigation system and dedicated software (ApproachViewer, part of GTx-Eyes II—UHN) were used to quantify the working volume of each approach and extrapolate the exposure of different ACF regions. Mixed linear models with random intercepts were used for statistical analyses.RESULTS: EEAs offer a large and direct route to the midline region of ACF, whose most anterior structures (ie, crista galli, cribriform plate, and ethmoidal roof) are also well exposed by anterior MTAs, whereas deeper ones (ie, planum sphenoidale and tuberculum sellae) are also well exposed by anterolateral MTAs. The orbital roof region is exposed by both anterolateral and lateral MTAs. The posterolateral region (ie, sphenoid wing and optic canal) is well exposed by anterolateral MTAs.CONCLUSION: Anterior and anterolateral MTAs play a pivotal role in the exposure of most anterior and posterolateral ACF regions, respectively, whereas midline regions are well exposed by EEAs. Furthermore, certain anterolateral approaches may be most useful when involvement of the optic canal and nerves involvement are suspected.
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| 2. |
- Bertl, Kristina, et al.
(author)
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Micro-CT evaluation of the cortical bone micro-architecture in the anterior and posterior maxilla and the maxillary sinus floor
- 2019
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In: Clinical Oral Investigations. - : Springer. - 1432-6981 .- 1436-3771. ; 23, s. 1453-1459
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Journal article (peer-reviewed)abstract
- Objectives: To perform a within-subject comparison of the cortical bone micro-architecture of the maxillary sinus floor (MSF) to that of the buccal aspect of the anterior and posterior maxilla. Methods: Micro-CT scans of the buccal aspect of the anterior and posterior maxilla and of the MSF in 14 human anatomical specimens were recorded. Within-subject comparisons were performed for cortical thickness (Ct.Th) and porosity (Ct.Po), average pore volume (AvgPo.V), and pore density (Po.Dn). Results: The MSF presented the lowest and the anterior maxilla the highest Ct.Th, while Ct.Po was significantly higher at the MSF compared to the posterior maxilla (p = 0.021). No relevant differences were recorded for AvgPo.V and Po.Dn among regions (p > 0.067). Further, an increased Ct.Th at the MSF was significantly associated with a lower Po.Dn, while a higher Ct.Th and an increased AvgPo.V in the anterior maxilla were associated with a higher Ct.Th and an increased AvgPo.V, respectively, in the posterior maxilla and MSF. Finally, within each region, the AvgPo.V was associated positively with Ct.Po and negatively with Po.Dn. Conclusions: The cortical bone of the MSF is slightly less thick and slightly more porous compared to the cortical bone at the buccal aspect of the anterior and posterior maxilla. Clinical relevance: During lateral and vertical bone augmentation procedures, the cortical recipient bone is perforated several times to open the bone marrow compartment to facilitate provision of osteoinductive cells and molecules in the augmented space. Whether it is meaningful to approach the MSF in a similar way during MSF augmentation procedures or whether the slightly more porous structure of the MSF observed herein reduces the cortical barrier function already sufficiently has to be assessed in future clinical trials.
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| 3. |
- Bertl, Kristina, et al.
(author)
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MicroCT-based evaluation of the trabecular bone quality of different implant anchorage sites for masticatory rehabilitation of the maxilla
- 2015
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In: Journal of Cranio-Maxillofacial Surgery. - : Elsevier. - 1010-5182 .- 1878-4119. ; 43:6, s. 961-968
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Journal article (peer-reviewed)abstract
- In the severely atrophied maxilla, implant anchorage in the zygomatic bone is considered a viable alternative to conventional dental implants with preceding bone augmentation procedures. The present microCT-based study compared the trabecular bone quality of the maxilla and zygomatic bone. MicroCT scanning was conducted in 12 halves of cadaver heads (5 male, 7 female) with edentulous, atrophied maxillae. Relevant trabecular bone quality parameters were determined in the anterior and posterior maxilla and in the zygomatic bone and compared by region and sex. Any difference in mean values between the anterior maxilla and the zygomatic bone was insignificant. Comparison of both with the posterior maxilla presented significantly higher values for bone volume fraction, surface density, and trabecular thickness and number, and significantly lower values for specific bone surface, structure model index, and trabecular separation. A significant sex-specific difference was not detected. The present microCT-based analysis is, to the best of our knowledge, the first intra-individual comparison of different implant anchorage sites for masticatory rehabilitation of the maxilla. The trabecular compartment of the zygomatic bone offered bone quality and, thus, an implant bed comparable with those of the anterior maxilla, and both were superior to the posterior maxilla.
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| 4. |
- Bertl, Kristina, et al.
(author)
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Radiological assessment of the inferior alveolar artery course in human corpse mandibles
- 2014
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In: European Radiology. - : Springer. - 0938-7994 .- 1432-1084. ; 25:4, s. 1148-1153
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Journal article (peer-reviewed)abstract
- Objectives: CT assessment of the entire course of the inferior alveolar artery (IAA) within the mandibular canal. Methods: After contrast medium injection (180 or 400 mg/ml iodine concentration) into the external carotid arteries of 15 fresh human cadaver heads, the main IAA’s position in the canal (cranial, buccal, lingual or caudal) was assessed in dental CT images of partially edentulous mandibles. Results: The course of the main IAA could be followed at both iodine concentrations. The higher concentration gave the ex- pected better contrast, without creating artefacts, and improved visibility of smaller arteries, such as anastomotic sections, dental branches and the incisive branch. The main IAA changed its position in the canal more often than so far known (mean 4.3 times, SD 1.24, range 2–7), but with a similar bilateral course. A cranial position was most often detected (42 %), followed by lingual (36 %), caudal (16 %) and buccal ( 6 %). Conclusions: With this non-invasive radiologic method, the entire course of the main IAA in the mandibular canal could be followed simultaneously with other bone structures on both sides of human cadaver mandibles. This methodology allows one to amend existing anatomical and histological data, which are important for surgical interventions near the mandibular canal.
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| 5. |
- Bertl, Kristina, et al.
(author)
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Relative Composition of Fibrous Connective and Fatty/Glandular Tissue in Connective Tissue Grafts Depends on the Harvesting Technique but not the Donor Site of the Hard Palate
- 2015
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In: Journal of Periodontology. - : American Academy of Periodontology. - 0022-3492 .- 1943-3670. ; 86:12, s. 1331-1339
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Journal article (peer-reviewed)abstract
- BACKGROUND: Whether the composition of palatal connective tissue grafts (CTGs) varies depending on donor site or harvesting technique in terms of relative amounts of fibrous connective tissue (CT) and fatty/glandular tissue (FGT) is currently unknown and is histologically assessed in the present study. METHODS: In 10 fresh human cadavers, tissue samples were harvested in the anterior and posterior palate and in areas close to (marginal) and distant from (apical) the mucosal margin. Mucosal thickness, lamina propria thickness (defined as the extent of subepithelial portion of the biopsy containing ≤25% or ≤50% FGT), and proportions of CT and FGT were semi-automatically estimated for the entire mucosa and for CTGs virtually harvested by split-flap (SF) preparation minimum 1 mm deep or after deepithelialization (DE). RESULTS: Palatal mucosal thickness, ranging from 2.35 to 6.89 mm, and histologic composition showed high interindividual variability. Lamina propria thickness (P >0.21) and proportions of CT (P = 0.48) and FGT (P = 0.15) did not differ significantly among the donor sites (anterior, posterior, marginal, apical). However, thicker palatal tissue was associated with higher FGT content (P <0.01) and thinner lamina propria (P ≤0.03). Independent of the donor site, DE-harvested CTG contained a significantly higher proportion of CT and a lower proportion of FGT than an SF-harvested CTG (P <0.04). CONCLUSION: Despite high interindividual variability in terms of relative tissue composition in the hard palate, DE-harvested CTG contains much larger amounts of CT and much lower amounts of FGT than SF-harvested CTG, irrespective of the harvesting site.
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| 6. |
- Pifl, Markus, et al.
(author)
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Histomorphometric analysis of the palatal soft tissue as donor region for retrieval of connective tissue grafts
- 2014
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Conference paper (other academic/artistic)abstract
- Objectives The soft tissue of the palate is the most frequently used donor side for connective tissue grafts. Various techniques have been described to harvest the connective tissue in anterior and posterior regions of the palate (Hürzeler 1999, Jung 2008, Zucchelli 2010). The present study assessed the histological composition of the soft tissue of the palate in the premolar and tuberosity region and compared the histological composition of connective tissue grafts harvested by two different techniques. Methods Tissue samples of the palatal soft tissue of 10 fresh human dentate cadaver heads were harvested in the premolar and tuberosity region. After histological processing, a histomorphometric analysis on the ratio between epithelium, connective tissue, fatty/glandular tissue, and vascular tissue was performed. Height and composition of the total palatal tissue and of digitally marked grafts (two different harvesting techniques: split-flap- and de-epithelialization-technique) were assessed in both regions (premolar and tuberosity) in an area close and more distant from the teeth (Figure 1). Results The height measurements of the palatal soft tissue ranged from 2.4 to 6.9mm. The main parameters (ratio of connective tissue and fatty/glandular tissue) presented no significant difference between the various regions (close and distant areas in the premolar and tuberosity region; p>0.145; Table 1). But significant differences were detected for the histological compositions of the connective tissue grafts (Table 2); the tissue gained by de-epithelialization in the tuberosity region contained a significantly higher amount of connective tissue, than the tissue gained by split-flap-technique in the premolar region (73.3 vs. 56.5%; p=0.041; Figure 2). Altogether, both, height measurements and composition of the palatal tissue, presented a high inter-individual variability (e.g., percentage of fatty/glandular tissue ranged from 0.04 to 73.8%; Figure 3). Comparison between genders revealed significantly higher values of connective tissue in the premolar region of males (p=0.045); all other parameters presented no relevant gender differences (p>0.077). Conclusions Thus far, the connective tissue harvested in the tuberosity region, which is most often done by de-epithelialization to prevent injury to the greater palatine artery (Figure 1), was clinically described to be denser and more firm compared to the tissue gained in the premolar region (most often by split-flap-technique) (Zuhr 2014). The present study is, to the best of our knowledge, the first to prove this clinical assumption with a histomorphometric analysis. Topic of future clinical trials will be to assess, whether the outcome of root coverage procedures is influenced by the histological composition of the graft (more or less fatty).
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