Valerian Dirr

Dr. Valerian Dirr

orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

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

Representative Publications

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25 May 2021 in Langenbeck's Archives of Surgery
Verified
Journal Article
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KUKristjan Ukegjini
Kristjan Ukegjini
DVDiana Vetter
Diana Vetter
RFRebecca Fehr
Rebecca Fehr
VDValerian Dirr
Valerian Dirr
CGChristoph Gubler
Christoph Gubler
CGChristian A. Gutschow
Christian A. Gutschow
Background: Surgery is the cornerstone of esophageal cancer treatment but remains burdened with significant postoperative changes of gastrointestinal function and quality of life. Purpose: The aim of this narrative review is to assess and summarize the current knowledge on postoperative functional syndromes and quality of life after esophagectomy for cancer, and to provide orientation for the reader in the challenging field of functional aftercare. Conclusions: Post-esophagectomy syndromes include various conditions such as dysphagia, reflux, delayed gastric emptying, dumping syndrome, weight loss, and chronic diarrhea. Clinical pictures and individual expressions are highly variable and may be extremely distressing for those affected. Therefore, in addition to a mostly well-coordinated oncological follow-up, we strongly emphasize the need for regular monitoring of physical well-being and gastrointestinal function. The prerequisite for an effective functional aftercare covering the whole spectrum of postoperative syndromes is a comprehensive knowledge of the pathophysiological background. As functional conditions often require a complex diagnostic workup and long-term therapy, close interdisciplinary cooperation with radiologists, gastroenterologists, oncologists, and specialized nutritional counseling is imperative for successful management.

24 November 2023 in Cancers
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Journal Article
Open access
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VDValerian Dirr
Valerian Dirr
DVDiana Vetter
Diana Vetter
TSThomas Sartoretti
Thomas Sartoretti
MSMarcel André Schneider
Marcel André Schneider
FCFrancesca Da Canal
Francesca Da Canal
CGChristian A. Gutschow
Christian A. Gutschow
Transthoracic esophagectomy results in a radical change in foregut anatomy with multiple consequences for digestive physiology. The aim of this study was to identify factors associated with poor functional outcomes by assessing multiple dimensions of digestive performance and health-related quality of life (HRQL). Patients with cancer-free survival after Ivor Lewis esophagectomy were included. Four functional syndromes (dysphagia, gastroesophageal reflux disease (GERD), delayed gastric conduit emptying (DGCE), and dumping syndrome (DS)) and HRQL were assessed using specifically designed questionnaires. Patient outcomes were compared with healthy controls. Independent factors associated with poor digestive performance were identified through multivariable analysis. Sixty-five postoperative patients and 50 healthy volunteers participated in this study. Compared with controls, patients had worse outcomes for dysphagia, GERD, DS, and HRQL, but not for DGCE. A multivariate analysis showed a significant correlation of reduced digestive performance with ASA score, squamous cell carcinoma, open or hybrid surgical approach, and (neo)adjuvant therapy. In contrast, no individual patient factor was found to be associated with dumping syndrome. Digestive function and HRQL are substantially impaired after Ivor Lewis esophagectomy for cancer. Comorbid patients undergoing multimodal treatment and open access surgery for squamous cell carcinoma have the highest risk of poor functional outcome.

28 March 2023 in Surgical Endoscopy
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Journal Article
Open access
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KUKristjan Ukegjini
Kristjan Ukegjini
DVDiana Vetter
Diana Vetter
VDValerian Dirr
Valerian Dirr
CGChristian A. Gutschow
Christian A. Gutschow
Background: Mesh augmentation is a highly controversial adjunct of hiatus hernia (HH) surgery. The current scientific evidence remains unclear and even experts disagree on indications and surgical techniques. With an aim to avoid the downsides of both non-resorbable synthetic and biological materials, biosynthetic long-term resorbable meshes (BSM) have recently been developed and are becoming increasingly popular. In this context, we aimed at assessing outcomes after HH repair with this new generation of mesh at our institution. Methods: From a prospective database, we identified all consecutive patients that underwent HH repair with BSM augmentation. Data was extracted from electronic patient charts of our hospital information system. Endpoints of this analysis included perioperative morbidity, functional results and recurrence rates at follow-up. Results: Between December 2017 and July 2022, 97 patients (elective primary cases n = 76, redo cases n = 13, emergency cases n = 8) underwent HH with BSM augmentation. Indications in elective and emergency cases were paraesophageal (Type II–IV) HH in 83%, and large Type I HH in 4%. There was no perioperative mortality, and overall (Clavien–Dindo ≥ 2) and severe (Clavien–Dindo ≥ 3b) postoperative morbidity was 15% and 3%, respectively. An outcome without postoperative complications was achieved in 85% of cases (elective primary surgery 88%, redo cases 100%, emergencies cases 25%). After a median (IQR) postoperative follow-up of 12 months, 69 patients (74%) were asymptomatic, 15 (16%) reported improvement, and 9 (10%) had clinical failure, of which 2 patients (2%) required revisional surgery. Conclusion: Our data suggest that HH repair with BSM augmentation is feasible and safe with low perioperative morbidity and acceptable postoperative failure rates at early to mid-term follow-up. BSM may be a useful alternative to non-resorbable materials in HH surgery.

15 April 2026 in Journal of Clinical Medicine
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Journal Article
Open access
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VDValerian Dirr
Valerian Dirr
LHLeyla Yasemin Halter
Leyla Yasemin Halter
MRMaximilian Alois Ries
Maximilian Alois Ries
GLGregoire Longchamp
Gregoire Longchamp
RFRaphael Ferrari
Raphael Ferrari
MWMaximilian E. H. Wagner
Maximilian E. H. Wagner
Background: Oral and cranio-maxillofacial (OCMF) surgery is a complex specialty that requires detailed anatomical knowledge and, in fracture care, the ability to interpret imaging accurately. Mixed reality (MR) may improve spatial understanding in anatomy-based disciplines, but its value for teaching mandibular fracture classification remains uncertain. Methods: Medical and dental students at the University of Zurich were randomized 1:1 to classify four unilateral mandibular fractures using either MR or conventional two-dimensional (2D) imaging. Primary outcomes were perceived usefulness, ease of use, learning, and user satisfaction, assessed with a 15-item usability questionnaire. Secondary outcomes were fracture-classification accuracy and time to fracture classification. Results: Forty medical and dental students were included. Baseline characteristics were comparable between groups, and overall fracture-classification accuracy did not differ significantly between MR and 2D. Both groups became faster across successive cases, indicating a learning effect, although the 2D group completed classifications more quickly overall. MR participants reported higher scores for learning and user satisfaction, whereas the 2D group rated ease of use more favorably. Conclusions: MR increased user satisfaction but did not improve fracture-classification accuracy compared with 2D imaging. When integrated thoughtfully into OCMF education, MR may complement, rather than replace, conventional imaging approaches.

Verified
Journal Article
Open access
PDF file
GLGregoire Longchamp
Gregoire Longchamp
HEHarald Essig
Harald Essig
VDValerian Dirr
Valerian Dirr
MPMarc M. Precht
Marc M. Precht
MWMaximilian E. H. Wagner
Maximilian E. H. Wagner
RFRaphael Ferrari
Raphael Ferrari
Background: The standard treatment for maxillofacial abscesses is surgical drainage combined with antibiotics, a frequent procedure in maxillofacial surgery departments. However, postoperative complications following this surgery are poorly described in the literature. Identifying their incidence and risk factors could help improve patient outcomes and healthcare planning. Objectives: The primary aim was to identify postoperative complications within 30 days after maxillofacial abscess surgery; the secondary aim was to explore their associated risk factors. Methods: A monocentric retrospective cohort study included patients with maxillofacial abscesses who underwent extraoral incision and drainage under general anesthesia at the Department of Cranio-Maxillofacial and Oral Surgery at a tertiary hospital in Switzerland between January 2012 and August 2023. Postoperative complications within 30 days were recorded and classified according to the validated Dindo–Clavien classification system. Univariable and multivariable logistic regression analyses were conducted to identify risk factors for postoperative complications. Results: A total of 253 participants were analyzed. The overall complication rate was 24.1%, with 15.8% major complications (Dindo–Clavien grade ≥ 3). The most common minor complications (Dindo–Clavien grade < 3) were hypokalemia and lower-extremity edema, with an incidence of 6.4%. The most common major complications were persistent and recurrent abscesses, with an incidence rate of 10.4%. These complications occurred in the early (median range 1–5 days) and delayed (median range 14–15 days) postoperative courses, respectively. Overall, the mortality rate was 0.4%. On multivariable analysis, an American Society of Anesthesiologists (ASA) score > 2 was associated with overall and major postoperative complications (odds ratio [OR], 3.38; 95% CI 1.75–6.51; p < 0.001 and OR, 3.76; 95% CI 1.83–7.72; p < 0.001, respectively). Additionally, female sex (OR, 1.97; 95% CI 1.05–3.70; p = 0.036) and C-reactive protein level > 50 mg/L (OR, 2.25; 95% CI 1.01–4.98; p = 0.046) were associated with overall postoperative complications. Conclusions: This study introduces a novel application of the Dindo–Clavien classification to maxillofacial abscess surgery, providing a standardized framework for assessing postoperative complication severity. Through this approach, we identified ASA score > 2, female sex, and CRP level > 50 mg/L as risk factors for postoperative complications. Our findings highlight the importance of close monitoring during the first five postoperative days to detect early complications, such as persistent abscesses, and recommend standardized outpatient follow-up for at least two weeks to identify delayed complications, like recurrence.