Abstracts DGPRÄC

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Background:
Approximately 3% of traumatic injuries involve peripheral nerves, and if left untreated, can result in the formation of neuromas.Subsequently these can manifest symptoms, including neuropathic pain, paresthesia, numbness, and cold intolerance.Ultimately this leads to functional limitations and reduced quality of life for the affected individuals.Despite the clinical relevance of this issue and the extensive research and clinical testing of numerous strategies to prevent and treat symptomatic neuromas, no single approach has emerged as the established standard method.This study aims to explore the effectiveness of combining a nerve cap, serving as a mechanical barrier, with chitosan, a biodegradable synthetic material that has gained increasing importance in the context of treating peripheral nerve injuries.

Materials and methods:
Using the rat sciatic nerve model, 48 SD-rats were divided into four groups.To replicate the relevant nerve defect, a nerve segment of at least 5mm was excised.In the first group, this was the only intervention (Control).Additional intervention in the other three groups consisted of bipolar coagulation (Coagulation) or the application of a nerve cap secured with three 9-0 ethilon sutures.One cap was a polylactic based cap (Polylactic), while the other utilized the biomaterial chitosan (Chitosan).Neuroma-growth and cap-degeneration were assessed through MR neurography in week 6 and 12.After 12 weeks the nerve was resected, and a macroscopic examination was conducted to assess perineural adhesion, neuroma-shape, and cap-degradation.Additionally, axonal density, axon diameter and myelin fiber thickness were evaluated histomorphometrically.

Results:
Histomorphometric evaluation and quantitative analysis revealed significant differences in the following parameters among the study groups.Axonal density was significantly reduced in the Control-Group when compared to the two groups with capped neuromas (Chitosan 7799 ± 2976, p = 0.0193; Polylactic 7605 ± 2169, p = 0.0029).When assessing axonal diameters, only the Chitosan-Group showed significantly thicker axons in comparison to the Control Group (0.176 ± 0.068, p = 0.0210).Analysis of the myelin fibers revealed that both the Chitosan-(0.104± 0.028, p = 0.0019) and the Polylactic-Group (0.082 ± 0.025, p = 0.0046) exhibited a greater myelin fiber thickness compared to the Control Group.No notable differences were observed in any histomorphometric categories when comparing the three Intervention-Groups with each other.Further, macroscopic evaluation of the perineural adhesion showed no significant difference between any of the study groups.Atypical neuroma with distal axonal outgrowth were most frequently observed in the Control-and Coagulation-Groups, while the neuromas in both the Chitosan-and Polylactic-Group presented in a more bulbous shape.Furthermore, the Chitosan-Caps displayed no significant signs of degradation, whereas the Polylactic-Caps had collapsed and were brittle during explantation.These findings were further supported by MR-Neurography, which revealed distal neurite outgrowth in both the Controland Coagulation-Group, as well as the absence of cap degradation in the other two groups.
The implementation of nerve caps as mechanical barriers resulted in the formation of denser, more typical shaped bulbous neuromas, which are associated with reduced neuropathic pain compared to atypical formed neuromas with distal neurite outgrowth and subsequential lower axonal density.Further histomorphometric analysis indicated that the caps had a positive impact on axon diameter and myelin fiber thickness.Consequently, employing a cap as a mechanical barrier shows a beneficial effect on neuroma formation when contrasted with neurotmesis alone, consolidating its potential in neuroma treatment and prevention.However, no significant differences were observed among the interventions, indicating that the use of chitosan does not provide any additional advantages.Moreover, the absence of significant capdegradation raises concerns regarding potential long-term issues, i.e. foreign-body reactions, which warrant further investigation in subsequent studies with extended observation periods.

Background:
Defects of the hand and foot often require an individualized reconstructive approach due to their unique functional and aesthetic characteristics.Transferred tissues should be thin, pliable, and durable, with free fascial flaps meeting these requirements.This study aimed to evaluate the serratus fascia flap and the serratus carpaccio flap, which is a modification of the fascia flap by including a thin muscle layer with the goal to enhance flap resilience and lower morbidity rates.

Materials and methods:
Between January 2000 and December 2017, 31 patients underwent microsurgical reconstruction of the hand or foot either by serratus fascia flap (fascia group) or serratus carpaccio flap (carpaccio group).The serratus fascia flaps were mainly harvested between 2000 and 2012, while the serratus carpaccio flaps between 2013 and 2017.Patient records were reviewed retrospectively regarding demographics, complications, overall flap survival, additional revision surgeries, and surgical outcome.Categorical variables were compared using Fisher's exact while continuous data with the Mann-Whitney tests.Logistic regression was used to examine the correlation between comorbidities and postoperative complication rates.Differences were considered significant when p < 0.05.

Results:
The fascia group consisted of 17 patients and the carpaccio group of 14 patients.The average patient age in the fascia group was 39.2 ± 10.5 years and, 39.1 ± 14.7 years in the carpaccio group, respectively.Overall complication rates were significantly lower in the carpaccio group than in the fascia group (28.6% vs 70.6%, p=0.03).The rates of overall flap survival (85.7% in carpaccio group vs 74.5% in fascia group, p=0.66) and partial flap loss (14.3% in carpaccio group vs 47.1% in fascia group, p=0.07) did not differ significantly among both groups.One postoperative hematoma of the donor-site requiring revision surgery was reported in the carpaccio group (7.1%, p=0.45) while no donor-site morbidity was reported in the fascia group.

Conclusion:
Our findings indicate that the serratus carpaccio flap presents a promising alternative to the serratus fascia flap.This modification has proven to be effective in substantially reducing postoperative complications requiring additional surgical interventions.Therefore, the serratus carpaccio flap can be considered a dependable reconstructive option for addressing complex soft tissue defects of the hand and foot, with complication rates that are within an acceptable range.Background: Among Caucasians, basal cell carcinoma, classified as a non-melanoma type of skin cancer, stands as the most encountered form of cancer.A significant majority of these tumors (roughly 80-90%) manifest on facial regions that receive direct sunlight Within this subset, lesions located on the nose present the most formidable challenge for surgeons, chiefly due to anatomical intricacies, functional considerations, and aesthetic concerns.

Intraoperative Blood Flow Analysis of Free Flaps with
The objective of the study was to assess the dispersion of tumor localization and size, morphological classifications, and the results of surgical intervention, encompassing the degree of radicality attained.
Additionally, the study sought to scrutinize the correlation between the level of radical excision and the subsequent recurrence rate.

Materials and methods:
The study utilized information sourced from the Health Information Centre at the Hygiene Institute.
Permissions to implement this study were granted by the Department of Bioethics, LUHSH (BEC - MF -123. 16-12-2022).The authors conducted a retrospective investigation, scrutinizing 343 instances of nasal skin cancer over a four-year timeframe, starting from January 1, 2019, to December 31, 2022.Medical records were selected based on ICD -10 -AM code: C44.3.Statistical analysis of the data was carried out using IBM SPSS Statistics 27.0 software.

Results:
The study encompassed patients with an average age of 75.18 years.The number of female participants notably exceeded that of males (252 females and 91 males), a difference found to be statistically significant (p < 0.001, χ2 = 75.571).The most prevalent tumor localizations were the left side of the nose, accounting for 87 cases (25.4%), and the dorsum nasi, accounting for 85 cases (24.8%).On average, tumor sizes were 0.79 ± 0.38 cm in females and 0.82 ± 0.44 cm in males.The infiltrative morphological type was the most frequently observed, with 243 cases (70.8%).In terms of tumor removal, excision with fasciocutaneous plastic surgery was significantly more prevalent, constituting 262 cases (76.4%) out of the total (p < 0.001, χ2 = 306.9).Complete excision was achieved in 271 lesions (79.0%), while incomplete excision occurred in 58 lesions (16.9%).Notably, there was a substantial correlation between nonradical excisions and a higher recurrence rate compared to radical excisions (24.1% and 6.3% respectively) (p < 0.001, χ2 = 18.108).For nonradically excised tumors, further management more frequently involved reexcision within 0 -6 months, accounting for 23 cases (39.7%), and reexcision upon recurrence, accounting for 17 cases (29.3%).

Conclusion:
Nasal reconstruction entails the application of a diverse set of surgical techniques that must be intricately tailored to account for variables such as tumor localization, size, depth, and patient-specific requirements.Despite the scrupulous adherence of surgeons to visual guidelines for excising basal cell carcinomas, the incidence of nonradical procedures cannot be entirely obviated.Nonetheless, we are confronted with the challenge posed by the escalating incidence of BCC cases, a consequence of demographic aging patterns.It is judicious to consider the incorporation of the Mohs micrographic technique as a means to enhance surgical outcomes and elevate the degree of radicality.