Dirk Halama

Dr. Dirk Halama

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Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Journal Article
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HMHelena Merkel
Helena Merkel
DLDirk Lindner
Dirk Lindner
KGKhaled Gaber
Khaled Gaber
SZSvitlana Ziganshyna
Svitlana Ziganshyna
JJJennifer Jentzsch
Jennifer Jentzsch
CRCindy Richter
Cindy Richter
Background: During the last decade, cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) was a current research focus without a standardized classification in digital subtraction angiography (DSA). This study was performed to investigate a device-independent visual cerebral vasospasm classification for endovascular treatment. Methods: The analyses are DSA based rather than multimodal. Ten defined points of intracranial arteries were measured in 45 patients suffering from cerebral vasospasm after SAH at three time points (hospitalization, before spasmolysis, control after six months). Mathematical clustering of vessel diameters was performed to generate four objective grades for comparison. Six interventional neuroradiologists in two groups scored 237 DSAs after a new visual classification (grade 0–3) developed on a segmental pattern of vessel contraction. For the second group, a threshold-based criterion was amended. Results: The raters had a reproducibility of 68.4% in the first group and 75.2% in the second group. The complementary threshold-based criterion increased the reproducibility by about 6.8%, while the rating deviated more from the mathematical clustering in all grades. Conclusions: The proposed visual classification scheme of cerebral vasospasm is suitable as a standard grading procedure for endovascular treatment. There is no advantage of a threshold-based criterion that compensates for the effort involved. Automated vessel analysis is superior to compare inter-group results in research settings.

12 October 2022 in Diagnostics
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DHDirk Halama
Dirk Halama
HMHelena Merkel
Helena Merkel
RWRobert Werdehausen
Robert Werdehausen
KGKhaled Gaber
Khaled Gaber
SSStefan Schob
Stefan Schob
CRCindy Richter
Cindy Richter
A threshold-based classification of cerebral vasospasm needs reference values for intracranial vessel diameters on digital subtraction angiography (DSA). We aimed to generate adjusted reference values for this purpose by retrospectively analyzing angiograms and potential influencing factors on vessel diameters. Angiograms of the anterior circulation were evaluated in 278 patients aged 18–81 years. The vessel diameters of 453 angiograms (175 bilateral) were gathered from nine defined measuring sites. The effect sizes of physical characteristics (i.e., body weight and height, body mass index, gender, age, and cranial side) and anatomical variations were calculated with MANOVA. Segments bearing aneurysms were excluded for the calculation of reference values. Adjusted vessel diameters were calculated via linear regression analysis of the vessel diameter data. Vessel diameters increased with age and body height. Male and right-sided vessels were larger in diameter. Of the anatomical variations, only the hypoplastic/aplastic A1 segment had a significant influence (p < 0.05) on values of the anterior cerebral artery and the internal carotid artery with a small effect size (|ω2| > 0.01) being excluded from the reference values. We provide gender-, age-, and side-adjusted reference values and nomograms of arterial vessel diameters in the anterior circulation.

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MNMichael-Tobias Neuhaus
Michael-Tobias Neuhaus
NGNils-Claudius Bernhard Gellrich
Nils-Claudius Bernhard Gellrich
ASAnna Katharina Sander
Anna Katharina Sander
BLBernd Lethaus
Bernd Lethaus
DHDirk Halama
Dirk Halama
RZRüdiger Zimmerer
Rüdiger Zimmerer
Open treatment of condylar head fractures (CHF) is considered controversial. In this retrospective cohort study our primary objective was therefore to assess bone resorption and remodeling as well as patients function after open treatment of CHF in a medium-term follow-up (15.1 ± 2.2 months). We included 18 patients with 25 CHF who underwent open reduction and internal fixation, between 2016 and 2021, in our analysis. The clinical data and cone-beam computed tomography (CBCT) datasets were analyzed. The condylar processes were segmented in the postoperative (T1) and follow-up (T2) CBCT scans. Volumetric and linear bone changes were the primary outcome variables, measured by using a sophisticated 3D-algorithm. The mean condylar head volume decreased non-significantly from 3022.01 ± 825.77 mm3 (T1) to 2878.8 ± 735.60 mm3 (T2; p = 0.52). Morphological alterations indicated remodeling and resorption. The pre-operative maximal interincisal opening (MIO) was 19.75 ± 3.07 mm and significantly improved to 40.47 ± 1.7 mm during follow-up (p = 0.0005). Low rates of postoperative complications were observed. Open reduction of CHF leads to good clinical outcomes and low rates of medium-term complications. This study underlines the feasibility and importance of open treatment of CHF and may help to spread its acceptance as the preferred treatment option.

1 October 2018 in Journal of Cranio-Maxillofacial Surgery
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NPNiels Christian Pausch
Niels Christian Pausch
CKChristoph Paul Kuhnt
Christoph Paul Kuhnt
DHDirk Halama
Dirk Halama

1 April 2017 in British Journal of Oral and Maxillofacial Surgery
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Journal Article
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HHHeike Huempfner-Hierl
Heike Huempfner-Hierl
THThomas Hierl
Thomas Hierl
DHDirk Halama
Dirk Halama

12 October 2020 in Plastic and Reconstructive Surgery
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ABAlexander Bartella
Alexander Bartella
DHDirk Halama
Dirk Halama
NPNiels C. Md Pausch
Niels C. Md Pausch
BLBernd Lethaus
Bernd Lethaus
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