Thomas Fortmann

Dr. Thomas Fortmann

Department of Medicine, Faculty of Health, Witten/Herdecke University, Witten, Germany

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

View All Publications
10 December 2020 in Brain Sciences
Verified
Journal Article
Open access
PDF file
SASamer Zawy Alsofy
Samer Zawy Alsofy
ISIoanna Sakellaropoulou
Ioanna Sakellaropoulou
Makoto NakamuraMakoto Nakamura
Makoto Nakamura
CEChristian Ewelt
Christian Ewelt
ASAsem Salma
Asem Salma
RSRalf Stroop
Ralf Stroop
Anterior-communicating artery (ACoA) aneurysms have diverse configurations and anatomical variations. The evaluation and operative treatment of these aneurysms necessitates a perfect surgical strategy based on review of three-dimensional (3D) angioarchitecture using several radiologic imaging methods. We analyzed the influence of 3D virtual reality (VR) reconstructions versus conventional computed tomography angiography (CTA) scans on the identification of vascular anatomy and on surgical planning in patients with unruptured ACoA aneurysms. Medical files were retrospectively analyzed regarding patient- and disease-related data. Preoperative CTA scans were retrospectively reconstructed to 3D-VR images and visualized via VR software to detect the characteristics of unruptured ACoA aneurysms. A questionnaire was used to evaluate the influence of VR on the identification of aneurysm morphology and relevant arterial anatomy and on surgical strategy. Twenty-six patients were included and 520 answer sheets were evaluated. The 3D-VR modality significantly influenced detection of the aneurysm-related vascular structure (p = 0.0001), the recommended head positioning (p = 0.005), and the surgical approach (p = 0.001) in the planning of microsurgical clipping. Thus, reconstruction of conventional preoperative CTA scans into 3D images and the spatial presentation in VR models enabled greater understanding of the anatomy and pathology, provided realistic haptic feedback for aneurysm surgery, and influenced operation planning and strategy.

30 January 2024 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
SASamer Zawy Alsofy
Samer Zawy Alsofy
MLMarc Lewitz
Marc Lewitz
KMKyra Meyer
Kyra Meyer
TFThomas Fortmann
Thomas Fortmann
EWEike Wilbers
Eike Wilbers
CEChristian Ewelt
Christian Ewelt
(1) Background: In this study, epidemiological, clinical, therapeutical, and haemostaseological variables were investigated regarding their correlation with the recurrence of chronic subdural haematomas to assess the risk of recurrence more reliably in everyday clinical practice. (2) Methods: In our retrospective study, the electronic records of 90 patients who underwent surgery for a chronic subdural haematoma at our institute between 1 January 2017 and 31 May 2021 were analysed regarding previously defined variables. (3) Results: In the patient collective, 33.33% of the 90 patients experienced a recurrence requiring treatment. The occurrence of a recurrence was not statistically significantly related to age, gender, known alcohol abuse, a specific location, extension over one or both hemispheres, the surgical method, or anticoagulant medication. However, the recurrence was statistically significantly related to haematoma width (p = 0.000007), septation (p = 0.005), and the existence of a coagulation disorder not treated with medication (p = 0.04). (4) Conclusions: In our study, the width of the haematoma, septation, and coagulation disorders not treated with medication were documented as risk factors for the occurrence of a chronic subdural haematoma. Identifying of these risk factors could help in adapting individual therapeutic concepts for chronic subdural haematomas.

14 January 2026 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
TFThomas Fortmann
Thomas Fortmann
SASamer Zawy Alsofy
Samer Zawy Alsofy
ASAntonio Santacroce
Antonio Santacroce
Makoto NakamuraMakoto Nakamura
Makoto Nakamura
CEChristian Ewelt
Christian Ewelt
RLRalph Edmund Lehrke
Ralph Edmund Lehrke
Background/Objectives: Patients with deep brain stimulation (DBS) require regular follow-up. When a sudden loss of therapeutic effect occurs, impedance abnormalities are often the underlying cause. If reprogramming cannot restore clinical benefit, revision surgery may be necessary to replace defective hardware. Since all three major manufacturers are used at our center, we analyzed our patient cohort to determine the incidence and causes of impedance abnormalities. Methods: All 601 patients who underwent de novo DBS implantation in Hamm between 2009 and 2025 were evaluated for impedance abnormalities. In cases requiring revision surgery, the specific cause was identified. The manufacturer, electrodes, and contacts involved were systematically analyzed. Results: A total of 25 of 601 patients required revision surgery. Revision rates were 2.67% in patients with Parkinson’s disease, 6.19% in those with a tremor, and 5.71% in those with dystonia. Across manufacturers, 7.6% of patients with a Medtronic system required revision surgery, compared with 3.4% of patients with an Abbott system and no patients with a Boston Scientific system. The primary causes of revision were electrode-related problems (19/25), followed by extension defects (6/25), connector issues (4/25), and, in one case, a generator defect (1/25). Conclusions: Only 4.16% of patients required revision surgery due to impedance abnormalities. Patients with a tremor and non-segmented electrodes showed a higher incidence than those with Parkinson’s disease or dystonia. Predominantly older Medtronic systems had the highest revision rate, whereas no Boston Scientific systems required revision. In most cases, the electrodes were the primary source of impedance abnormalities. A total of 52% of revisions were performed within two years and 92% were performed within six years of implantation.

28 November 2023 in Brain Sciences
Verified
Journal Article
Open access
PDF file
TFThomas Fortmann
Thomas Fortmann
SASamer Zawy Alsofy
Samer Zawy Alsofy
MLMarc Lewitz
Marc Lewitz
ASAntonio Santacroce
Antonio Santacroce
HSHeinz Welzel Saravia
Heinz Welzel Saravia
RLRalph Edmund Lehrke
Ralph Edmund Lehrke
(1) Background: Infections in deep brain stimulation (DBS) hardware, while an undesired complication of DBS surgeries, can be effectively addressed. Minor infections are typically treated with wound revision and IV antibiotics. However, when visible hardware infection occurs, most centers opt for complete removal, leaving the patient in a preoperative state and necessitating post-removal care. To avoid the need for such care, a novel technique was developed. (2) Methods: The electrodes are placed at the exact same spot and then led to the contralateral side. new extensions and a new generator contralateral to the infection as well. Subsequently, the infected system is removed. This case series includes six patients. (3) Results: The average duration of DBS system implantation before the second surgery was 272 days. Only one system had to be removed after 18 months due to reoccurring infection; the others remained unaffected. Laboratory alterations and pathogens were identified in only half of the patients. (4) Conclusions: The described surgical technique proves to be safe, well tolerated, and serves as a viable alternative to complete system removal. Importantly, it effectively prevents the need of post-removal care for patients.

6 December 2023 in Surgeries
Verified
Journal Article
Open access
PDF file
EWEike Wilbers
Eike Wilbers
SASamer Zawy Alsofy
Samer Zawy Alsofy
SSStephanie Schipmann
Stephanie Schipmann
CEChristian Ewelt
Christian Ewelt
TFThomas Fortmann
Thomas Fortmann
MSMichael Schwake
Michael Schwake
Idiopathic obstruction of the outlets of the fourth ventricle (FVOO) is a rare cause of hydrocephalus, which can be misdiagnosed as communicating hydrocephalus due to the enlargement of all four ventricles. Different surgical approaches are discussed in the literature. We present a case report of a 25-year-old male admitted with headache, vertigo, and nystagmus. The MRI scan showed a tetraventricular hydrocephalus with a patent aqueduct. After endoscopic third ventriculostomy (ETV), symptoms resolved. We performed a systematic review of the literature, covering 26 years, with the aim to investigate the symptoms, therapy, and outcome of primary FVOO, according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. We found 9 case reports and 2 case series and could extract a total of 34 cases. After ETV all symptoms resolved in 10 of 23 cases (43.5%), and in 13 of 23 cases (56.5%) symptoms improved partially. Seven cases (30.4%) required additional surgery. A decrease in ventricular volume occurred in most cases. In the 10 patients who were operated via fenestration, all symptoms resolved in 6 cases. ETV seems to be an effective treatment option for patients with idiopathic FVOO in a majority of cases. In special cases, fenestration of the foramen of Magendie may be suitable.

22 October 2025 in Journal of Surgery
Verified
Journal Article
Open access
PDF file
TFThomas Fortmann
Thomas Fortmann
SASamer Zawy Alsofy
Samer Zawy Alsofy
RSRalf Stroop
Ralf Stroop
ASAntonio Santacroce
Antonio Santacroce
MNMakoto Nakamura
Makoto Nakamura
RLRalph Lehrke
Ralph Lehrke
By Thomas Fortmann · 2025 · Read by 87 — Stereotactic parietal transtentorial placement of a catheter into a pontine cyst of a pilocytic astrocytoma is a safe treatment option in Journal of Surgery