Jan Hambrecht

Dr. Jan Hambrecht

orcid

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

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

Representative Publications

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22 March 2024 in Pain
Verified
Journal Article
Closed access
AGAli E. Guven
Ali E. Guven
GEGisberto Evangelisti
Gisberto Evangelisti
Marco D. BurkhardMarco D. Burkhard
Marco D. Burkhard
PKPaul Köhli
Paul Köhli
JHJan Hambrecht
Jan Hambrecht
AHAlexander P. Hughes
Alexander P. Hughes
Lumbar medial branch radiofrequency neurotomy (RFN), a common treatment for chronic low back pain due to facet joint osteoarthritis (FJOA), may amplify paraspinal muscle atrophy due to denervation. This study aimed to investigate the asymmetry of paraspinal muscle morphology change in patients undergoing unilateral lumbar medial branch RFN. Data from patients who underwent RFN between March 2016 and October 2021 were retrospectively analyzed. Lumbar foramina stenosis (LFS), FJOA, and fatty infiltration (FI) functional cross-sectional area (fCSA) of the paraspinal muscles were assessed on preinterventional and minimum 2-year postinterventional MRI. Wilcoxon signed-rank tests compared measurements between sides. A total of 51 levels of 24 patients were included in the analysis, with 102 sides compared. Baseline MRI measurements did not differ significantly between the RFN side and the contralateral side. The RFN side had a higher increase in multifidus FI (+4.2% [0.3-7.8] vs +2.0% [−2.2 to 6.2], P = 0.005) and a higher decrease in multifidus fCSA (−60.9 mm2 [−116.0 to 10.8] vs −19.6 mm2 [−80.3 to 44.8], P = 0.003) compared with the contralateral side. The change in erector spinae FI and fCSA did not differ between sides. The RFN side had a higher increase in multifidus muscle atrophy compared with the contralateral side. The absence of significant preinterventional degenerative asymmetry and the specificity of the effect to the multifidus muscle suggest a link to RFN. These findings highlight the importance of considering the long-term effects of lumbar medial branch RFN on paraspinal muscle health.

20 November 2023 in European Journal of Orthopaedic Surgery & Traumatology
Verified
Journal Article
Open access
PDF file
JHJan Hambrecht
Jan Hambrecht
CCClaudio Canal
Claudio Canal
FKFelix Karl Ludwig Klingebiel
Felix Karl Ludwig Klingebiel
CPCyrill Pfammatter
Cyrill Pfammatter
MTMichel Paul Johan Teuben
Michel Paul Johan Teuben
CHChristian Hierholzer
Christian Hierholzer
Purpose: Elective implant removal (IR) in the upper extremity remains controversial. Implants in the olecranon and clavicle are commonly removed for prominence, unlike in the distal radius. Patient-reported symptomatic cannot be verified, and nonspecific discomfort remains unquantified. In this study, indications and outcomes of IR at the clavicle, olecranon and distal radius were evaluated, with a focus on postoperative patient satisfaction. Materials and methods: In this retrospective, single-center cohort study, patients, who received elective IR of the clavicle, olecranon and distal radius were included. Patients were followed up at least six weeks after IR. Outcomes included patient satisfaction, symptom resolution, and complications. Results: One hundred and eighty-nine patients were included. Unspecific symptoms of discomfort were the most prevalent indication for IR (48.7%), followed by pain (29.6%) and objective limited range of motion (ROM) (7%). Pain and limited ROM combined was observed in 13.8%. Subjective benefit following IR was described in 54%. Patients with limited ROM (OR 4.7, p < 0.001) or pain (OR 4.1, p < 0.001) were more likely to experience alleviation of complaints. Patients with unspecific symptoms of discomfort, often did not report improvement. Major complications occurred in 2%. Refractures were detected at the clavicle (3.7%) and at the olecranon (2.5%). Minor complication rate was 5%. Conclusion: IR is a safe procedure in the upper extremity. Indications based on unspecific symptoms of discomfort have a significant lower rate of patient satisfaction postoperatively. Elective IR should be considered cautiously, if it is driven primarily by unspecific symptoms of discomfort. Patient education is relevant to prevent dissatisfying outcome.

14 September 2024 in The Spine Journal
Verified
Journal Article
Closed access
JHJan Hambrecht
Jan Hambrecht
PKPaul Köhli
Paul Köhli
ECErika Chiapparelli
Erika Chiapparelli
JZJiaqi Zhu
Jiaqi Zhu
AGAli E. Guven
Ali E. Guven
AHAlexander P. Hughes
Alexander P. Hughes

13 June 2025 in European Spine Journal
Verified
Journal Article
Closed access
PDF file
ECErika Chiapparelli
Erika Chiapparelli
Thomas CaffardThomas Caffard
Thomas Caffard
SMSamuel J. Medina
Samuel J. Medina
KAKrizia Amoroso
Krizia Amoroso
JZJiaqi Zhu
Jiaqi Zhu
AHAlexander P. Hughes
Alexander P. Hughes

21 February 2025 in European Journal of Trauma and Emergency Surgery
Verified
Journal Article
Open access
PDF file
FKFranziska Kessler
Franziska Kessler
YKYannik Kalbas
Yannik Kalbas
JHJan Hambrecht
Jan Hambrecht
VWVictoria Wlach
Victoria Wlach
SHSascha Halvachizadeh
Sascha Halvachizadeh
CHChristian Hierholzer
Christian Hierholzer
Purpose: Removal of symptomatic hardware after fracture fixation is common, especially in patients with clavicle fracture. Yet, refracture after hardware removal is a relatively common complication in those patients. The aim of this study was to identify risk factors for clavicle refractures that could be influenced by the surgical treatment provided. Methods: All patients from a level one trauma center from 2017 to 2022 were screened for eligibility. Inclusion criteria included hardware removal after plate osteosynthesis of the clavicle, age ≥ 18 years, and signed informed consent. Groups were stratified according to occurrence of refracture: no-refracture (NR) vs. refracture (R). Nearest-neighbor matching in a ratio of 5:1 was performed. Parameter investigated included baseline demographics, fracture characteristics and surgical treatment details. A subgroup analysis of only clavicle shaft fractures was performed. Results: Sixty patients were included with 50 patients in Group NR and 10 in Group R. Baseline characteristics were comparable between the groups. A subgroup analysis on shaft fractures revealed that a significantly larger working length (number of empty screw holes adjacent to the fracture site) in Group NR (1.94 ± 0.85) compared to the refracture group (1.20 ± 0.92) (p = 0.042). Logistic regression yielded an inverse correlation with the number of empty screw holes to the fracture site and the occurrence of refractures (OR 0.369, 95% CI 0.132–0.873; p = 0.035). Time in situ, lag screw application, plate positioning and the total amount of screws did not affect either of the groups. Conclusion: An increased working length in patients with clavicle shaft fractures might be a protective measure for occurrence of refractures after hardware removal.

27 June 2024 in European Spine Journal
Verified
Journal Article
Closed access
PDF file
ECErika Chiapparelli
Erika Chiapparelli
Marco D. BurkhardMarco D. Burkhard
Marco D. Burkhard
KAKrizia Amoroso
Krizia Amoroso
AGAli E. Guven
Ali E. Guven
GCGaston Camino-Willhuber
Gaston Camino-Willhuber
AHAlexander P. Hughes
Alexander P. Hughes