Abstracts DGPRÄC

s – DGCH Annual Congress 2019 – Munich, March 26–29 • DOI 10.1515/iss-2019-2007 s393 Innov Surg Sci 2019; 4, (Suppl 1): s393–s412

Perforator flaps have become a popular option in reconstructive tissue transfers. Consistent with the "hot/cold zone" concept for rapid dissection and thin flap harvest, reliable pre-operative perforator mapping is mandatory. Systematic review of the literature has demonstrated color-coded duplex sonography (CCDS) to have the highest pooled sensitivity and positive predictive valueto identify perforating vessels. The question remains: why has CCDS for micro vessel mapping not been more widely applied by microsurgeons? The following presentation of a step-by-step guide reviews the following aspects: 1. probe selection and device settings 2. structured mapping approach 3. pedicle position planning 4. safe flap design 5. prediction of perforator course 6. advanced application. Decisive practical steps are demonstrated with a patient series.

Materials and methods:
Experiences with ultrasound-guided flap design gained from perforator flap free tissue transfers performed 7/2013-3/2019, without using other technology, was the basis of our guide. Our structured method comprises standardized markings, patient positioning, and simple ergonomics. Basic CCDS pre-settings, selection, and conventional probe guidance are outlined for the microsurgeon. Easy orientation through different tissue layers and framing of micro vessels in color duplex mode are described. Power Doppler and B-flow mode may be added to enhance sensitivity for small perforators. Pulse Wave (PW)-mode aids in perforator selection.

Results:
Linear multifrequency probes (6 to 15 MHz) were used for perforator detection.Favorable device properties are depth of focus set to 3-5 cm, color gain set low enough to reduce extravascular color signals, wall filter (WF) low,and pulse repetition frequency (PRF) low to 0.5-20 Hz. Preset programs facilitate settings. A 100% concordance rate was seen comparing pre-operative perforator visualization with CCDS and intraoperative findings. CCDS proved to be easy to learn for the microsurgeon, inexpensive, convenient, and highly accurate. Picture and video material is demonstrated to illustrate tissue appearance and perforator characteristics.

Conclusion:
CCDS is a powerful tool for the microsurgeon to perform preoperative micro vessels mapping and evaluation in perforator flaps.

Background:
Soft-tissue filler injections for the treatment of facial aging can result in different skin surface effects depending on the targeted facial fat compartment and fascial plane. This work investigates the tissue response of defined amounts of injected soft-tissue filler material into superficial and deep facial fat compartments via the calculation of the surface-volume coefficient.

Materials and methods:
Four fresh frozen cephalic specimens obtained from human donors (3 female, 1 male; mean age 74.96 ± 22.6 years; mean BMI 21.82 ± 6.3 kg/m2) were studied. The superficial and deep lateral forehead compartments, deep temporal fat pad, sub-orbicularis oculi fat compartment and the deep medial cheek fat compartment were injected with aliquots of 0.1cc of contrast enhanced material and scanned using 3D surface imaging.

Conclusion:
These results, confirmatory in their nature to current injection strategies, provide evidence for the validity and reliability of the surface-volume coefficient. Injection procedures should be targeted in terms offacial fat compartments and fascial planes for a desired aesthetic outcome as each fat compartment and fascial plane has unique tissue responses to injected soft-tissue fillers. The axillary acne inversa is a common skin disease that often requires a surgical approach.
In many cases, appropriate therapy can be provided through excision of the entire sweat-glandbearing area. The resulting defects pose a challenge to the plastic surgeon due to the localization and the regularly severely scarred surrounding tissue. Usually, local flaps or skin grafts are applied to achieve defect coverage.

Materials and methods:
In this case, we demonstrate soft tissue reconstruction with a TDAP flap in a patient with postoperative scarring and movement restriction following resection of axillary acne inversa and secondary wound healing.

Results:
There were no major complications in wound healing. The Shoulder was functional and the movement was not restricted when compared with the opposite side.

Conclusion:
We discuss postoperative outcome after excisional therapy and secondary wound healing versus immediate axillary soft tissue reconstruction using pedicled thoracodorsal-artery perforator (TDAP) flaps regarding OR Time, functional and aesthetic outcome.
According to our experience the TDAP flap is an excellent alternative for the immediate coverage of axillary defects after resection of acne inversa.
Advantages are the reduced donor site morbitity, the wide arc of rotation and the delicate skin texture. Disadvantages might be extended operating time.

Universitätsklinikum Regensburg
Background: Necrotising fasciitis (NF) is a live threatening infection involving the deep fascia and subcutaneous tissue. Without surgery it is marked by rapid progression with high lethality. Differential diagnosis with other soft tissue infections is often difficult and delayed. Clinical signs vary from reddening, swelling and unproportionate pain.
NF can be classified into three categories, which respect localization disease and triggering bacteria. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC)-Score has been described for differentiation.
The aim of this study is to develop an algorithm by laboratory parameters, radiological imaging, histopathological findings and clinical signs to quickly confirm the correct diagnosis and consequently indicate an appropriate surgical treatment. Goals were limb salvage, function and survival.

Materials and methods:
Between the 2008 and 2018 cases of NF at the Department of Plastic-, Hand-and Reconstructive Surgery at the University Hospital of Regensburg were included. Our retrospective study examined the value of LRINEC, finger test and other clinical signs to diagnose and assess the extent of the disease. Surgical interventions and plastic reconstructions are evaluated.

Results:
A total of forty-two patients could be included. All cases required plastic-surgical interventions by serial debridement followed by soft tissue reconstruction.
A guiding algorithm including new parameters as the LRINEC-Score, finger test and more signs is presented. LRINEC-score is a laboratory test for necrotizing fasciitis including the parameters Haemoglobin, Leucocytes, Sodium, Creatinin, Glucose and CRP. It has proven its value for our cohort.
The finger-test may show a weak bleeding and putride secretion after incision of the skin and subcutaneous tissue. If digital splitting of the deep fascia is possible the test result is positive.
Leading clinical symptoms include early signs by fever, hypotension, erythema, tachypnoea or tachycardia, edema and limited vigilance.
Late signs comprise hemorrhagic bullae of the skin, crepitations of subcutaneous soft tissue or muscles, dark blue to black skin coloration, skin necrosis and multi organ failure. Patient examples are illustrated.

Conclusion:
Early diagnosis of NF helps to save live and limb. In our cohort the value of clinical signs like finger test and lab diagnostics like the LRINEC-Score could be confirmed. Early interdisciplinary treatment by intensive care medicine, plastic surgery and other disciplines is mandatory to increase survival. Instant and consequent debridements show good results in stopping progressive spread of disease as seen in secondary explorations. Soft tissue reconstruction improves function.

Background:
Purpura fulminans (PF) is a critical disease caused by meningococcal septicaemia mostly in childhood. It is characterized by high lethality, extensive necroses and mutilations of extremities. Other ethiologies are idiopathic forms or purpura neonatorum, which is characterized by deficiency of protein C. PF is triggered by micro-embolism of the vascular system, followed by quickly spreading necroses of skin and different organs. Modern concepts of intensive care treatment in the acute phase of the disease and early surgical interventions lead to a rising number of surviving patients requiring limb salvage. Aim of this study is to evaluate a two-center case series to define determining factors for lower morbidity, improved extremity salvage and better function through early surgical interventions.

Materials and methods:
Between 1998 and 2018 patients with PF at two centers for critical wound care, the department of plastic-, hand-and reconstructive surgery of the university hospital of Regensburg and the Department of Plastic Surgery, BG-Clinic Ludwigshafen, Heidelberg University, Germany were included into our study.
Our retrospective study examined patients with PF, which were stabilized by intensive care medicine and received different surgical interventions. After survival of the acute phase patients received plastic surgical reconstructions.

Results:
A total number of eight patients could be included. All patients survived the first phase. All cases required plastic-surgical interventions, because of extensive loss of skin and soft tissue. Flap reconstruction was judged as necessary in five cases. Hereby four defects could be reconstructed with free tissue transfer, one by a local flap. Flap survival was at 100 percent. One case needed revision of arterial anastomosis.
Cases that received early debridements including consequent fasciotomies and secondary plasticsurgical reconstructions rendered good functional results. Limb salvage was achieved in three patients. One patient died because of the fulminant progress of the disease.

Conclusion:
Management of PF requires a multidisciplinary approach and close communication between the different subspecialties. Early debridements with consequent fasciotomies showed good results in salvaging subfascial muscle tissue in the extremities with satisfying functional results. Early surgical interventions is a key factor for improved limb salvage and survival.

Materials and methods:
From 2010 until 2018 12 partial or complete toe transfers were carried out at the University Medical Center Regensburg. Juxtaposed was a control group of patients treated with contending reconstructive procedures.

Results:
A total of 4 neurovascular pulp transplantations and 8 osteocutaneous-partial (2), complete (2), as well as vascularized toe joint (4) transfers were carried out. Nine flaps healed without complications, one pulp transfer demonstrated inadequate blood perfusion but was maintained as a composite graft. All toe transplant healed without loss of length in the phalanges. Range of motion, remaining length and resensitization have proven to be superior in free toe transplants opposed to the control group treated with contending methods.

Conclusion:
In our heterogenic patient collective free toe transplants have proven to be superior for functional reconstruction of two and tripartite phalanxes opposed to common local reconstructive procedures. However, their indication should follow a strict protocol. Finger pulp regions can be substituted by homogenous sensitive ridged skin, lost joints may be replaced by autologous neojoints. Donor site morbidity was moderate.  When faced with plantar defects, reconstruction of the weight-bearing areas presents unique surgical challenges. Several free flap modalities have been described in this respect, but there remains debate regarding the best suited flap modality. Aim of this study is to compare free muscle and nonneurotized fasciocutaneous flaps for plantar reconstruction in respect to long-term functional outcomes.

Materials and methods:
Overall, 89 patients received 100 free flaps (ALT n=46; gracilis n=54) for plantar reconstruction. The data were screened for patients' demographics, as well as perioperative details. Postoperative complications were accounted for and the two groups compared accordingly. All patients were contacted for a long-term follow-up examination.

Results:
There were no significant differences between the two groups regarding major-(24 versus 17 percent; p=0.366) and minor surgical complications (61 versus 70 percent; p=0.318). However, the ALT group showed a significantly higher need for secondary surgeries (39 versus 19 percent; p=0.022). 68 patients (76 percent) returned for long-term follow-up evaluation (mean 51.2 months, range 13-71 months). The ALT group showed significantly less pain at the recipient-(p=0.0004) and donor (p=0.010) sites and scar assessment revealed significantly better results (p<0.001). Additionally, the ALT group showed better depth-(p=0.017) and superficial (p=0.007) sensation and enabled better shoe provision (p=0.014).

Conclusion:
Both, the free ALT-and gracilis flaps are well suited for plantar reconstruction, yielding overall similar functional outcomes. However, the ALT flap produces less scarring and pain, while showing better recovery of sensation and enabling better shoe provision. The ALT-flap thus presents our preferred option.

Prince of Wales Hospital, Sydney
Background: With continuously rising BMIs in our society and the growing accessibility of patients to bariatric surgery body lift procedures are becoming more and more common. These contouring surgeries are invasive and complicated surgical interventions. We want to present a new simple staging concept for the surgical contouring of the lower body and describe our method of auto-augmenting the gluteal region in a circumferential body lift.

Materials and methods:
All in all 41 patients underwent a circumferential lower body lift procedure in the last 3 years. 25 patients underwent the procedures without auto augmentation of the gluteal region and 16 patients were operated including an auto-augmentation of the buttock area. To augment the buttock area a modified perforator flap technique was applied "SGA perforator rotation flap". Results of both groups were compared regarding operating time, complication rates, overall result. Cosmetic results were analysed using conventional standardized photography and 3D scanning. The scans were performed with an high resolution Artec 3D scanner pre and post surgery.

Results:
A significant improvement of buttock contouring can be achieved with this operating method. Aesthetic results can be individualised to patient's wishes/expectations: -by flap design (shape, width, length, thickness) -by pocket dissection (shape, width, depth) -by flap fixation (sutures, infra-gluteal fold reconstruction (lower pole)). Complication rates were not higher in the augmentation group when compared to the conventional body lift group.

Conclusion:
The auto-augmentation of the gluteal region in a body lift procedure via "SGA perforator rotation flap" is safe, reliable and very effective technique to overcome the undesired flat buttock problem accompanied with conventional lower body lift procedures. 3D scanning is an objective method to compare and improve techniques in body contouring surgery. Microscopic analysis of peripheral nerves is key to many clinical and basic science research projects. In the past, no prime and uniform method could be found that is simple, cost-efficient, and timesparing. For small research collectives, manual analysis has been used. Attempts have been made by several research groups throughout medical and scientific communities to automate this process. These methods are often highly specialized and therefore only accessible to a few specialized laboratories. Within our facial nerve study, it was necessary to create an efficient, cost-effective method for axon quantification, due to the large number of 1238 nerve biopsies examined.

Materials and methods:
A total of 106 cadaveric facial halves were dissected, up to 19 extracranial specimens of the facial and masseteric nerve were biopsied. Slides were histologically prepared with PPD staining and 200x magnified transections were digitized using a microscope (Zeiss Imager Z1) with a mounted camera (Zeiss Axio cam MR). A refined method for semi-automatic axon counting was developed aiming to combine the accuracy and low-cost of manual counts with the speed of automated morphometry using widely available Fiji freeware. This method combined several processing and analyzing steps into one macro so that multiple images can be processed instantly (Figure 1). Manual counts were obtained using a count and click method with the cell counter function in Fiji freeware. A statistical comparison between the novel method and manual counts was carried out using 129 randomly selected biopsies from a study cohort of 1238 (10.4%).

Results:
Semi-automatic axon counting took 1 hour and 47 minutes for all 129 biopsies (average 50 sec per biopsy). The counting process is automatic and must not be accompanied. Manual counting took 21 hours and 6 minutes in total (average 9 minutes and 49 seconds per biopsy). The novel technique shows a linear correlation to the manual method (R=0.944 Spearman rho). The semi-automatic method to find nerve biopsies with >900 axons was found to be sensitive (94%) and specific (87%).

Conclusion:
The novel semi-automatic technique proved to be very time-sparing compared to the manual counting method. In absolute axon counts there is a loss of accuracy within larger nerve biopsies. However, the cut-off value of 900 can be determined reliably. Therefore, we suggest our user-friendly, cost-effective and time-efficient method can be suggested as an alternative in microscopic peripheral nerve morphometry in anatomic studies considering axon margins. Based on precision validation its applicability may be enlarged to other cranial and peripheral nerves.