Karl-Friedrich Kowalewski

Dr. Karl-Friedrich Kowalewski


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

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

Representative Publications

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1 January 2020 in Annals of Surgery
Verified
Journal Article
Closed access
FNFelix Nickel
Felix Nickel
CHCaelán Max Haney
Caelán Max Haney
KKKarl-Friedrich Kowalewski
Karl-Friedrich Kowalewski
PPPascal Probst
Pascal Probst
ELEldridge Frederick Limen
Eldridge Frederick Limen
THThilo Hackert
Thilo Hackert
Objective: To compare perioperative outcomes of laparoscopic pancreaticoduodenectomy (LPD) to open pancreaticoduodenectomy (OPD) using evidence from randomized controlled trials (RCTs). Background: LPD is used more commonly, but this surge is mostly based on observational data. Methods: We searched CENTRAL, Medline and Web of Science for RCTs comparing minimally invasive to OPD for adults with benign or malignant disease requiring elective pancreaticoduodenectomy. Main outcomes were 90-day mortality, Clavien-Dindo ≥3 complications, and length of hospital stay (LOS). Secondary outcomes were postoperative pancreatic fistula (POPF), delayed gastric emptying (DGE), postpancreatectomy hemorrhage (PPH), bile leak, blood loss, reoperation, readmission, oncologic outcomes (R0-resection, lymph nodes harvested), and operative times. Data were pooled as odds ratio (OR) or mean difference (MD) with a random-effects model. Risk of bias was assessed using the Cochrane Tool and the GRADE approach (Prospero registration ID: CRD42019120363). Results: Three RCTs with a total of 224 patients were included. Meta-analysis showed there were no significant differences regarding 90-day mortality, Clavien-Dindo ≥3 complications, LOS, POPF, DGE, PPH, bile leak, reoperation, readmission, or oncologic outcomes between LPD and OPD. Operative times were significantly longer for LPD {MD [95% confidence interval (CI)] 95.44 minutes (24.06–166.81 minutes)}, whereas blood loss was lower for LPD [MD (CI) −150.99 mL (−168.54 to −133.44 mL)]. Certainty of evidence was moderate to very low. Conclusions: At current level of evidence, LPD shows no advantage over OPD. Limitations include high risk of bias and moderate to very low certainty of evidence. Further studies should focus on patient safety during LPD learning curves and the potential role of robotic surgery.

17 March 2021 in Cancers
Verified
Journal Article
Open access
PDF file
JMJulia Mühlbauer
Julia Mühlbauer
LELuisa Egen
Luisa Egen
KKKarl-Friedrich Kowalewski
Karl-Friedrich Kowalewski
MGMaurizio Grilli
Maurizio Grilli
MWMargarete Teresa Walach
Margarete Teresa Walach
MKMaximilian Christian Kriegmair
Maximilian Christian Kriegmair
Radiomics may increase the diagnostic accuracy of medical imaging for localized and metastatic RCC (mRCC). A systematic review and meta-analysis was performed. Doing so, we comprehensively searched literature databases until May 2020. Studies investigating the diagnostic value of radiomics in differentiation of localized renal tumors and assessment of treatment response to ST in mRCC were included and assessed with respect to their quality using the radiomics quality score (RQS). A total of 113 out of 1098 identified studies met the criteria and were included in qualitative synthesis. Median RQS of all studies was 13.9% (5.0 points, IQR 0.25–7.0 points), and RQS increased over time. Thirty studies were included into the quantitative synthesis: For distinguishing angiomyolipoma, oncocytoma or unspecified benign tumors from RCC, the random effects model showed a log odds ratio (OR) of 2.89 (95%-CI 2.40–3.39, p < 0.001), 3.08 (95%-CI 2.09–4.06, p < 0.001) and 3.57 (95%-CI 2.69–4.45, p < 0.001), respectively. For the general discrimination of benign tumors from RCC log OR was 3.17 (95%-CI 2.73–3.62, p < 0.001). Inhomogeneity of the available studies assessing treatment response in mRCC prevented any meaningful meta-analysis. The application of radiomics seems promising for discrimination of renal tumor dignity. Shared data and open science may assist in improving reproducibility of future studies.

15 June 2021 in Langenbeck's Archives of Surgery
Verified
Journal Article
Open access
PDF file
EKEva Kalkum
Eva Kalkum
RKRosa Klotz
Rosa Klotz
SSSvenja Seide
Svenja Seide
FHFelix J. Hüttner
Felix J. Hüttner
KKKarl-Friedrich Kowalewski
Karl-Friedrich Kowalewski
PPPascal Probst
Pascal Probst
Background: Systematic reviews are an important tool of evidence-based surgery. Surgical systematic reviews and trials, however, require a special methodological approach. Purpose: This article provides recommendations for conducting state-of-the-art systematic reviews in surgery with or without meta-analysis. Conclusions: For systematic reviews in surgery, MEDLINE (via PubMed), Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL) should be searched. Critical appraisal is at the core of every surgical systematic review, with information on blinding, industry involvement, surgical experience, and standardisation of surgical technique holding special importance. Due to clinical heterogeneity among surgical trials, the random-effects model should be used as a default. In the experience of the Study Center of the German Society of Surgery, adherence to these recommendations yields high-quality surgical systematic reviews.

1 March 2018 in Journal of Surgical Education
Verified
Journal Article
Closed access
PRPhilipp Romero
Philipp Romero
PGPatrick Günther
Patrick Günther
KKKarl-Friedrich Kowalewski
Karl-Friedrich Kowalewski
MFMirco Friedrich
Mirco Friedrich
MSMona W. Schmidt
Mona W. Schmidt
FNFelix Nickel
Felix Nickel

9 March 2017 in Surgical Endoscopy
Verified
Journal Article
Closed access
PDF file
KKKarl-Friedrich Kowalewski
Karl-Friedrich Kowalewski
JHJonathan D. Hendrie
Jonathan D. Hendrie
MSMona W. Schmidt
Mona W. Schmidt
TPTanja Proctor
Tanja Proctor
SPSai Paul
Sai Paul
FNFelix Nickel
Felix Nickel

21 February 2019 in Surgical Endoscopy
Verified
Journal Article
Closed access
PDF file
KKKarl-Friedrich Kowalewski
Karl-Friedrich Kowalewski
CGCarly R. Garrow
Carly R. Garrow
MSMona W. Schmidt
Mona W. Schmidt
LBLaura Benner
Laura Benner
BMBeat P. Müller-Stich
Beat P. Müller-Stich
FNFelix Nickel
Felix Nickel