Nikolaus Wachtel

Dr. Nikolaus Wachtel

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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

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NWNikolaus Wachtel
Nikolaus Wachtel
Paul HeidekruegerPaul Heidekrueger
Paul Heidekrueger
CBCarolin Brenner
Carolin Brenner
MEMaximilian Endres
Maximilian Endres
RBRainer Burgkart
Rainer Burgkart
Denis EhrlDenis Ehrl
Denis Ehrl
The closure of wounds and subsequent optimal wound healing is essential to any successful surgical intervention. Especially on parts of the body with limited possibilities for local reconstruction, optimal distribution of load is essential. The aim of the present study was therefore to examine three different incision patterns, conventional straight, Lazy-S and Zigzag, with regard to their biomechanical stability and mode of failure on a porcine skin model. Our results demonstrate the superior biomechanical stability of Lazy-S and Zigzag incision patterns with perpendicular suture placement. This holds true, in particular, for Zigzag incisions, which showed the highest values for all parameters assessed. Moreover, the observed superior stability of Lazy-S and Zigzag incision patterns was diminished when sutures were placed in tensile direction. The conventional straight incision represents the standard access for a large number of surgical procedures. However, we were able to demonstrate the superior biomechanical stability of alternative incision patterns, in particular the Zigzag incision. This is most likely caused by an improved distribution of tensile force across the wound due to the perpendicular placement of sutures. Moreover, this technique offers additional advantages, such as a better overview of the operated area as well as several cosmetic improvements. We therefore advocate that the surgeon should consider the use of a Zigzag incision over a conventional straight incision pattern.

21 November 2022 in Diagnostics
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Nicholas MoellhoffNicholas Moellhoff
Nicholas Moellhoff
STSara Taha
Sara Taha
NWNikolaus Wachtel
Nikolaus Wachtel
MHMaximilian Hirschmann
Maximilian Hirschmann
MHMarc Hellweg
Marc Hellweg
Denis EhrlDenis Ehrl
Denis Ehrl
Background: Microsurgical tissue transfer revolutionized reconstructive surgery after extensive trauma, oncological resections, and severe infections. Complex soft tissue reconstructions are increasingly performed in multimorbid and elderly patients. Therefore, it is crucial to investigate whether these patients benefit from these complex procedures. Objective: To evaluate the outcome for multimorbid patients who underwent microsurgical soft tissue reconstruction and to identify potential risk factors that may increase mortality. Methods: This single-center study retrospectively analyzed prospectively collected data of patients receiving free gracilis (GM) or latissimus dorsi muscle (LDM) flap reconstruction between September 2017 and December 2021. Cases were divided into two groups (dead vs. alive), depending on patient survival. Patient demographics, comorbidities and medication, perioperative details, free flap outcome, as well as microcirculation were determined. Results: A total of 151 flaps (LDM, n = 67; GM, n = 84) performed in 147 patients with a mean age of 61.15 ± 17.5 (range 19–94) years were included. A total of 33 patients (22.45%) passed away during the study period. Deceased patients were significantly older (Alive: 58.28 ± 17.91 vs. Dead: 71.39 ± 11.13; p = 0.001), were hospitalized significantly longer (Alive: 29.66 ± 26.97 vs. Dead: 36.88 ± 15.04 days; p = 0.046) and suffered from cardiovascular (Alive: 36.40% vs. Dead: 66.70%; p = 0.002) and metabolic diseases (Alive: 33.90% vs. Dead: 54.50%; p = 0.031) more frequently, which corresponded to a significantly higher ASA Score (p = 0.004). Revision rates (Alive: 11.00% vs. Dead: 18.20%; p = 0.371) and flap loss (Alive: 3.39% vs. Dead: 12.12%; p = 0.069) were higher in patients that died by the end of the study period. Conclusions: Free flap transfer is safe and effective, even in multimorbid patients. However, patient age, comorbidities, preoperative ASA status, and medication significantly impact postoperative patient survival in the short- and mid-term and must, therefore, be taken into account in preoperative decision-making and informed consent.

1 April 2023 in Bone & Joint Open
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NWNikolaus Wachtel
Nikolaus Wachtel
EMEmanuel Meyer
Emanuel Meyer
EVElias Volkmer
Elias Volkmer
NKNina Knie
Nina Knie
BLBernhard Lukas
Bernhard Lukas
WDWolfram Demmer
Wolfram Demmer
Aims: Wrist arthroscopy is a standard procedure in hand surgery for diagnosis and treatment of wrist injuries. Even though not generally recommended for similar procedures, general administration of perioperative antibiotic prophylaxis (PAP) is still widely used in wrist arthroscopy.Methods: A clinical ambispective dual-centre study was performed to determine whether PAP reduces postoperative infection rates after soft tissue-only wrist arthroscopies. Retrospective and prospective data was collected at two hospitals with departments specialized in hand surgery. During the study period, 464 wrist arthroscopies were performed, of these 178 soft-tissue-only interventions met the study criteria and were included. Signs of postoperative infection and possible adverse drug effects (ADEs) of PAP were monitored. Additionally, risk factors for surgical site infection (SSIs), such as diabetes mellitus and BMI, were obtained.Results: The overall infection rate of SSI was zero. Neither in the PAP group (n = 69) nor in the control group (n = 109) were signs of postoperative infection observed. Observed symptoms of ADEs were three-times higher in the PAP group when compared to the control-group (16.3 vs 5.5%; p = 0.043). No major ADEs were observed, but one in ten patients in the PAP group reported mild to severe intestinal or hypersensitivity symptoms.Conclusion: We demonstrate that the number needed to treat (NNT) with PAP to prevent one postoperative infection in soft-tissue arthroscopies of the wrist is > 109. Conversely, symptoms of ADEs were reported by one out of ten patients given PAP. Considering the high NNT to prevent postoperative infection and the large number of ADEs caused by PAP, we recommend not to use PAP routinely in soft-tissue arthroscopies of the wrist. Subsequent large-scale studies should be conducted to substantiate these results.Cite this article: Bone Jt Open 2023;4(4):219–225.

17 March 2020 in International Journal of Colorectal Disease
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DEDenis Ehrl
Denis Ehrl
MRMarkus Rentsch
Markus Rentsch
NMNicholas Moellhoff
Nicholas Moellhoff
NWNikolaus Wachtel
Nikolaus Wachtel
Background: Crohn’s disease (CD) is a chronic inflammatory disorder which leads to anorectal fistulas. In rare cases, patients develop anal squamous cell carcinoma (ASCC) within these lesions. There is limited literature regarding ASCC in patients with CD. Here, we report on a unique case of advanced verrucous carcinoma (VC), a rare variant of squamous cell carcinoma, developing on the grounds of extensive chronic anorectal fistulas in CD. Methods and results: A 54-year-old male patient with a 20-year history of CD presented with a large inflammatory tumor at the perineal region with multiple discharging perianal fistulas. Histopathological analysis of the perineal mass revealed a VC. Subsequent surgery with radical tumor resection and terminal colostomy resulted in a large perineal cavity and a partially exposed sacrum. The defect extended to a total of 35 × 25 × 25 cm. Reconstruction was achieved through a two-step approach. A first surgical step established an arteriovenous (AV) loop in the upper thigh. Subsequently, a free latissimus dorsi (LD) myocutaneous flap was harvested and anastomosed with the AV loop, allowing for satisfactory closure of the defect and reconstruction of the perianal and perineal region. Conclusion: Radical surgical excision with negative margins is the therapy of choice for VC. This case report demonstrates a curative treatment option with special emphasis on the reconstructive possibilities of a unique case of extended perianal and perineal VC associated with chronic anorectal fistulas in CD.

15 August 2024 in Journal of Clinical Medicine
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KKKonstantin C. Koban
Konstantin C. Koban
CKConstanze Kuhlmann
Constanze Kuhlmann
NWNikolaus Wachtel
Nikolaus Wachtel
MHMaximilian Hirschmann
Maximilian Hirschmann
MHMarc Hellweg
Marc Hellweg
Denis EhrlDenis Ehrl
Denis Ehrl
Background: The use of free gracilis muscle flaps in reconstructive surgery of the lower leg is common practice to cover defects. However, there is still a lack of understanding of the morphometric changes that occur in the transferred muscle and area of interest over time, particularly the characteristic volume decrease that is observed over the course of the first year. This study aimed to assess volume changes in patients with free gracilis muscle flap reconstruction following infection, trauma, or malignancies of the lower extremity. Methods: Three-dimensional surface imaging was performed intraoperatively after 2 weeks, 6 months, and 12 months with the Vectra H2 system. A total of 31 patients were included in this study and analyzed. Results: There was an average volume increase of 146.67 ± 29.66% 2 weeks after reconstruction. Compared to this volume increase, there was a reduction of 108.44 ± 13.62% after 12 months (p < 0.05). Overall, we found a shrinkage to 85.53 ± 20.14% of the intraoperative baseline volume after 12 months. Conclusions: The use of non-invasive 3D surface imaging is a valuable tool for volume monitoring after free flap reconstruction of the lower extremity. The free gracilis muscle flap undergoes different phases of volume change over the first year, with the greatest influence on overall change being the development and decongestion of edema. Precise initial surgical tailoring is crucial for optimal long-term functional and cosmetic results.

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Denis EhrlDenis Ehrl
Denis Ehrl
NWNikolaus Wachtel
Nikolaus Wachtel
DBDavid Braig
David Braig
CKConstanze Kuhlmann
Constanze Kuhlmann
HDHans Roland Dürr
Hans Roland Dürr
RGRiccardo E. Giunta
Riccardo E. Giunta
Autologous fillet flaps are a common reconstructive option for large defects after forequarter amputation (FQA) due to advanced local malignancy or trauma. The inclusion of osseous structures into these has several advantages. This article therefore systematically reviews reconstructive options after FQA, using osteomusculocutaneous fillet flaps, with emphasis on personalized surgical technique and outcome. Additionally, we report on a case with an alternative surgical technique, which included targeted muscle reinnervation (TMR) of the flap. Our literature search was conducted in the PubMed and Cochrane databases. Studies that were identified were thoroughly scrutinized with regard to relevance, resulting in the inclusion of four studies (10 cases). FQA was predominantly a consequence of local malignancy. For vascular supply, the brachial artery was predominantly anastomosed to the subclavian artery and the brachial or cephalic vein to the subclavian or external jugular vein. Furthermore, we report on a case of a large osteosarcoma of the humerus. Extended FQA required the use of the forearm for defect coverage and shoulder contour reconstruction. Moreover, we performed TMR. Follow-up showed a satisfactory result and no phantom limb pain. In case of the need for free flap reconstruction after FQA, this review demonstrates the safety and advantage of osteomusculocutaneous fillet flaps. If the inclusion of the elbow joint into the flap is not possible, we recommend the use of the forearm, as described. Additionally, we advocate for the additional implementation of TMR, as it can be performed quickly and is likely to reduce phantom limb and neuroma pain.