Pedicled ALT-flap for soft tissue reconstruction in the trochanteric area.

BACKGROUND: Coverage of soft tissue defects following surgery at the trochanteric area is challenging. Revision surgery in case of compromised wound healing may lead to soft tissue defects requiring reconstruction with pedicled or free flaps. Previous access to the hip joint may jeopardize neurovascular structures relevant to the flap. OBJECTIVE: In this study, we evaluated if the use of a pedicled anterior lateral thigh (ALT) flap is a valuable option for soft tissue reconstruction. METHODS: In this retrospective study, seven patients were included. Defect etiology was tumor resection in one case, screw osteosynthesis in another case and total hip arthroplasty in three cases. All patients underwent reconstruction by proximal pedicled anterior lateral thigh (ALT) flap. RESULTS: Pedicled ALT flap was a safe procedure in all cases. One patient showed delayed wound healing with need for additional surgery. No further complications were observed. CONCLUSIONS: Pedicled ALT flap transfer represents a reliable option for soft tissue coverage in the trochanteric area after primary surgery such as hip arthroplasty, osteosynthesis or tumor resection.

Bilateral deficiency of Meissner corpuscles and papillary microvessels in patients with acute complex regional pain syndrome.

ABSTRACT: Complex regional pain syndrome (CRPS) presents postinjury with disproportionate pain and neuropathic, autonomic, motor symptoms, and skin texture affection. However, the origin of these multiplex changes is unclear. Skin biopsies offer a window to analyze the somatosensory and vascular system as well as skin trophicity with their protecting barriers. In previous studies, barrier-protective exosomal microRNAs were altered in CRPS. We here postulated that tissue architecture and barrier proteins are already altered at the beginning of CRPS. We analyzed ipsilateral and contralateral skin biopsies of 20 fully phenotyped early CRPS patients compared with 20 age- and sex-matched healthy controls. We established several automated unbiased methods to comprehensively analyze microvessels and somatosensory receptors as well as barrier proteins, including claudin-1, claudin-5, and claudin-19. Meissner corpuscles in the skin were bilaterally reduced in acute CRPS patients with some of them lacking these completely. The number of Merkel cells and the intraepidermal nerve fiber density were not different between the groups. Dermal papillary microvessels were bilaterally less abundant in CRPS, especially in patients with allodynia. Barrier proteins in keratinocytes, perineurium of dermal nerves, Schwann cells, and papillary microvessels were not affected in early CRPS. Bilateral changes in the tissue architecture in early CRPS might indicate a predisposition for CRPS that manifests after injury. Further studies should evaluate whether these changes might be used to identify risk patients for CRPS after trauma and as biomarkers for outcome.

[Goal-setting in Plastic Surgery using the SMART principle]. / Operative Ausbildungsziele in der Plastischen und Ästhetischen Chirurgie einfach "SMART".

INTRODUCTION: The process of continuous acquisition of surgical expertise is a key element in registrar training. The principle of active, self-directed learning, which is regularly applied in medical school, can also be used to gain surgical expertise in registrar training. METHODS: Surgical training can be compared to acquiring expertise in music or sport, where both intellectual and manual capabilities are required. Specific training principles, including analysis, goal setting, practice and reflection on the process, are commonly encountered in these fields. Smart goal setting is preferred in order to ensure compliance and a successful strategy. This can also be used in plastic surgery training. APPLICATION: Surgical principles as well as partial or complete surgical procedures can be practiced using the smart principle. The fragmentation of a larger task into smaller units allows rapid acquisition of surgical expertise without impeding patient safety. DISCUSSION: Surgical training today happens in a setting caught between economic and medicolegal challenges. The reduction of case load requires simulation practice as well as self-directed learning - which has been shown to improve outcomes. The smart principle allows distinct goal setting which can improve compliance of the student and increase success. As this form of learning is not intuitive to all individuals, supervisors and mentor can support trainees in the acquisition of surgical expertise using this principle.

Development and preclinical evaluation of a cable-clamp fixation device for a disrupted pubic symphysis.

BACKGROUND: Traumatic separation of the pubic symphysis can destabilize the pelvis and require surgical fixation to reduce symphyseal gapping. The traditional approach involves open reduction and the implantation of a steel symphyseal plate (SP) on the pubic bone to hold the reposition. Despite its widespread use, SP-fixation is often associated with implant failure caused by screw loosening or breakage. METHODS: To address the need for a more reliable surgical intervention, we developed and tested two titanium cable-clamp implants. The cable served as tensioning device while the clamp secured the cable to the bone. The first implant design included a steel cable anterior to the pubic symphysis to simplify its placement outside the pelvis, and the second design included a cable encircling the pubic symphysis to stabilize the anterior pelvic ring. Using highly reproducible synthetic bone models and a limited number of cadaver specimens, we performed a comprehensive biomechanical study of implant stability and evaluated surgical feasibility. RESULTS: We were able to demonstrate that the cable-clamp implants provide stability equivalent to that of a traditional SP-fixation but without the same risks of implant failure. We also provide detailed ex vivo evaluations of the safety and feasibility of a trans-obturator surgical approach required for those kind of fixation. CONCLUSION: We propose that the developed cable-clamp fixation devices may be of clinical value in treating pubic symphysis separation.

Life-threatening pelvic injuries are often associated with disruption of a joint within the hip bones, called the pubic symphysis. Disruption can lead to a gap and subsequent instability of the pelvis. The current treatment is to stabilize the joint with a steel plate and screws, however this often becomes unstable soon after the operation. In this study, we analyzed two alternatives for stabilization that use cables and clamps instead of the plate. Further, we tested a surgical approach for implantation. The cables and clamps were as stable as a steel plate so offer an alternative approach to stabilize the pubic symphysis.

[Pedicled anterolateral thigh flap reconstruction in the region of the lower abdomen, groin, perineum, and hip]. / Die gestielte, anterolaterale Oberschenkellappenplastik zur Weichteilrekonstruktion im Bereich von Unterbauch, Leiste, Perineum und Hüfte.

OBJECTIVE: Soft tissue reconstruction of complex defects of the lower abdomen, groin, the perineum and the hip region present a reconstructive challenge. Besides free tissue transfer, pedicled flaps may also be utilized. Harvest of the vertical rectus abdominis flap causes a functional deficit by weakening the abdominal wall. Pedicled, perforator-based flaps minimize functional deficits by preserving muscle. INDICATIONS: Soft tissue defects with exposed vital structures, prosthetic devices or irradiated wound beds. CONTRAINDICATIONS: Previous surgery at the donor site, peripheral vascular disease at the pelvic and thigh region, previous vascular interventions at the donor site. SURGICAL TECHNIQUE: After preoperative localization of the perforators, a retrograde, intramuscular dissection of the pedicle allows sufficient length to be gained in order to transpose the flap into the defect. Tunneling of the flap beneath the rectus femoris muscle and Sartorius muscle is often required for tension-free inset. POSTOPERATIVE MANAGEMENT: Five days of bed-rest postoperatively followed by ambulation. RESULTS: No complete flap loss was encountered in 13 cases. In 2 cases a partial tip necrosis required secondary skin grafting.

[Vascular diagnostics before microvascular tissue transfer on the lower extremities : An algorithm]. / Gefäßdiagnostik vor mikrovaskulärem Gewebetransfer an der unteren Extremität : Ein Algorithmus.

Microsurgical free flap transfer plays a key role in soft tissue reconstruction of the lower extremities. Through close cooperation between plastic and orthopedic surgery, great progress and success in limb salvage could be achieved over the last decades. The risk for extremity malperfusion is especially high in older patients and after trauma. To maximize the success rate for free flap transfer there is need for interdisciplinary clinical examination and diagnostics. In addition to clinical methods radiological procedures are necessary to evaluate and optimize lower extremity perfusion before surgery.Vascular ultrasound provides important information about the arterial and venous status; however, DSA, CTA and MRA are well-established and exact methods to evaluate arterial inflow. The use of less invasive methods makes it much more feasible, economic and comfortable to perform preoperative selection of patients requiring interventional procedures.In the case of intraluminal stenosis without any option for PTA, a vascular surgeon can be involved at an early stage to evaluate further surgical options. In some cases, similar surgical revascularization and free flap transfer can be performed in a single surgery. The aim of this study is to implement a standardized algorithm for preoperative examination and radiological diagnostics before reconstructive surgery of the lower extremity.

Central perforated VRAM flap and neurostimulated levator augmentation for functional and aesthetical reconstruction after abdominoperineal excision in cancer.

BACKGROUND: Preservation of quality of life regarding fecal continence after abdominoperineal excision (APE) in cancer is challenging. Simultaneous soft tissue coverage and restoration of continence mechanism can be provided through an interdisciplinary collaboration of colorectal and plastic reconstructive surgery. OBJECTIVE: Evaluation of surgical procedure and outcome combining soft tissue reconstruction using a central perforated vertical rectus abdominis myocutaneous flap (VRAM), implementing a perineostoma and restoring anorectal angle augmenting the levator ani by neurostimulated graciloplasty. METHODS: 14 Patients underwent APE due to cancer. In all patients coverage was achieved by pedicled VRAM and simultaneous pull-through descendostomy (perineostoma). 10 of those patients received a levator augmentation additionally. Postoperative complications, functional measures of continence as well as quality of life were obtained. RESULTS: Perineal minor complication rate was 43% without need of surgical intervention. All but one VRAM survived. Continence measures and disease specific life quality showed a good preservation of continence in most patients. CONCLUSION: The results present a complex therapy option accomplished by a collaboration of two highly specialized partners (visceral and plastic surgery) after total loss of the sphincter function and consecutive fecal insufficiency after APE.

Assessing the scapholunate and lunotriquetral interosseous ligament in MR arthrography: Diagnostic advantages of paraxial reformatting.

PURPOSE: The scapholunate (SLIL) and lunotriquetral interosseous ligament (LTIL) function as the main stabilizers of the proximal carpal row. Even with MR arthrography, component assessability is often limited in orthogonal standard planes due to their horseshoe-like shape and resulting partial volume effects. This study aims to investigate the diagnostic value of reformatting isotropic 3D sequences with respect to the anatomical orientation of the intrinsic carpal ligaments. METHOD: In 110 MR arthrograms of the wrist, we investigated the diagnostic accuracy of two radiologists (R1/R2) for SLIL and LTIL injuries in orthogonal standard planes vs. ancillary angulated reformatting of isotropic 3D dual echo steady state sequence. Component assessability and diagnostic confidence were compared between datasets. RESULTS: The addition of paraxial reformations improved diagnostic accuracy for lesions of the palmar (R1: 0.87 vs. 0.93; R2: 0.86 vs. 0.93; all p < 0.05) and dorsal LTIL (R1: 0.85 vs. 0.93; R2: 0.82 vs. 0.90; all p < 0.05). No significant increase in accuracy could be ascertained for palmar (R1: 0.92 vs. 0.94, p = 0.50; R2: 0.86 vs. 0.92, p = 0.07) and dorsal (R1: 0.95 vs. 0.95, p = 1.00; R2: 0.90 vs. 0.94, p = 0.29) lesions of the SLIL. Interrater reliability was almost perfect with and without angulated planes for SLIL (κ = 0.88 vs. 0.82) and LTIL assessment (κ = 0.88 vs. 0.86). For the LTIL, observer confidence and component assessability were superior with anatomical reformations available (all p < 0.05). CONCLUSIONS: In contrast to SLIL injuries, diagnosis of LTIL lesions benefits from ancillary paraxial reformations of 3D sequences in MR wrist arthrography.

Managing esophagocutaneous fistula after secondary gastric pull-up: A case report.

BACKGROUND: Gastric pull-up (GPU) procedures may be complicated by leaks, fistulas, or stenoses. These complications are usually managed by endoscopy, but in extreme cases multidisciplinary management including reoperation may be necessary. Here, we report a combined endoscopic and surgical approach to manage a failed secondary GPU procedure. CASE SUMMARY: A 70-year-old male with treatment-refractory cervical esophagocutaneous fistula with stenotic remnant esophagus after secondary GPU was transferred to our tertiary hospital. Local and systemic infection originating from the infected fistula was resolved by endoscopy. Hence, elective esophageal reconstruction with free-jejunal interposition was performed with no subsequent adverse events. CONCLUSION: A multidisciplinary approach involving interventional endoscopists and surgeons successfully managed severe complications arising from a cervical esophagocutaneous fistula after GPU. Endoscopic treatment may have lowered the perioperative risk to promote primary wound healing after free-jejunal graft interposition.

Improved diagnostic accuracy for ulnar-sided TFCC lesions with radial reformation of 3D sequences in wrist MR arthrography.

OBJECTIVES: Triangular fibrocartilage complex (TFCC) injuries frequently cause ulnar-sided wrist pain and can induce distal radioulnar joint instability. With its complex three-dimensional structure, diagnosis of TFCC lesions remains a challenging task even in MR arthrograms. The aim of this study was to assess the added diagnostic value of radial reformatting of isotropic 3D MRI datasets compared to standard planes after direct arthrography of the wrist. METHODS: Ninety-three patients underwent wrist MRI after fluoroscopy-guided multi-compartment arthrography. Two radiologists collectively analyzed two datasets of each MR arthrogram for TFCC injuries, with one set containing standard reconstructions of a 3D thin-slice sequence in axial, coronal and sagittal orientation, while the other set comprised an additional radial plane view with the rotating center positioned at the ulnar styloid. Surgical reports (whenever available) or radiological reports combined with clinical follow-up served as a standard of reference. In addition, diagnostic confidence and assessability of the central disc and ulnar-sided insertions were subjectively evaluated. RESULTS: Injuries of the articular disc, styloid and foveal ulnar attachment were present in 20 (23.7%), 10 (10.8%) and 9 (9.7%) patients. Additional radial planes increased diagnostic accuracy for lesions of the styloid (0.83 vs. 0.90; p = 0.016) and foveal (0.86 vs. 0.94; p = 0.039) insertion, whereas no improvement was identified for alterations of the central cartilage disc. Readers' confidence (p < 0.001) and assessability of the ulnar-sided insertions (p < 0.001) were superior with ancillary radial reformatting. CONCLUSIONS: Access to the radial plane view of isotropic 3D sequences in MR arthrography improves diagnostic accuracy and confidence for ulnar-sided TFCC lesions. KEY POINTS: • In multi-compartment arthrography of the wrist, ancillary radial plane view aids assessability of the foveal and styloid ulnar-sided insertions of the triangular fibrocartilage complex. • Assessment of peripheral TFCC injuries is more accurate with access to radial multiplanar reconstructions. • Additional radial planes provide greater diagnostic confidence.

Experimental Drillable Magnesium Phosphate Cement Is a Promising Alternative to Conventional Bone Cements.

Clinically used mineral bone cements lack high strength values, absorbability and drillability. Therefore, magnesium phosphate cements have recently received increasing attention as they unify a high mechanical performance with presumed degradation in vivo. To obtain a drillable cement formulation, farringtonite (Mg3(PO4)2) and magnesium oxide (MgO) were modified with the setting retardant phytic acid (C6H18O24P6). In a pre-testing series, 13 different compositions of magnesium phosphate cements were analyzed concentrating on the clinical demands for application. Of these 13 composites, two cement formulations with different phytic acid content (22.5 wt% and 25 wt%) were identified to meet clinical demands. Both formulations were evaluated in terms of setting time, injectability, compressive strength, screw pullout tests and biomechanical tests in a clinically relevant fracture model. The cements were used as bone filler of a metaphyseal bone defect alone, and in combination with screws drilled through the cement. Both formulations achieved a setting time of 5 min 30 s and an injectability of 100%. Compressive strength was shown to be ~12-13 MPa and the overall displacement of the reduced fracture was <2 mm with and without screws. Maximum load until reduced fracture failure was ~2600 N for the cements only and ~3800 N for the combination with screws. Two new compositions of magnesium phosphate cements revealed high strength in clinically relevant biomechanical test set-ups and add clinically desired characteristics to its strength such as injectability and drillability.

Muscle Cuff in Distal Pedicled Adipofascial Sural Artery Flaps: A Retrospective Case Control Study.

Amputation after open tibial fracture occurs in 3% of cases. The rate increases when flap reconstruction is required. The standard care involves microsurgical tissue transfer although the pedicled reverse sural artery adipofascial flap (PRSAF) is a local alternative in patients endangered by a prolonged operative time. Incorporation of a gastrocnemius muscle cuff in this flap can be used to fill dead space and increase healing potential. Literature shows superior survival rates for both PRSAF and inclusion of a muscle cuff in comparison with the cutaneous version. The aim of the study was to compare the outcome of the PRSAF and the musculoadipofascial version (PRSMAF). We hypothesize that the PRSMAF provides similar lap viability and flap-related complication rates as does the adipofascial version. The muscle component may reduce the long-term osteomyelitis rate. METHODS: Patients were evaluated retrospectively after reconstruction with either PRSAF or PRSMAF. Preoperative osteomyelitis, flap survival, complications and osteomyelitis clearance were analyzed. RESULTS: The study shows preliminary results supporting the potential use of the PRSMAF. We compare either 23 PRSMAF or 20 PRSAF flaps. We found no statistically significant differences in flap survival or in complication rate. CONCLUSIONS: Although the anatomical situation may sometimes dictate the use of a free flap, a technically less-complicated option may in some cases offer a viable alternative. This study shows that the PRSMAF can serve as an alternative for complex bone defects in the limb, though it does not provide statistical improvement to the PRSAF.

Complex Soft Tissue Defects in Operative Urology: Pedicled Perforator Flaps of the Anterior Lateral Thigh for Tissue Reconstruction of the Lower Trunk.

BACKGROUND: Complex soft tissue defects involving the lower abdomen, perineum, and groin (LAPG) represent reconstructive challenges following urologic surgery. Consequently, these often require an interdisciplinary approach involving plastic surgery. While pedicled flaps from the lower abdomen are a reliable option, previous placement of colostomies and urinary urostomies renders these flap types unavailable. Here, the pedicled anterolateral thigh perforator (ALT) flap represents a reliable pedicled alternative which can harvest from the thigh. MATERIALS AND METHODS: A retrospective data analysis of pedicled perforator flaps harvested from the thigh to reconstruct soft tissue defects was conducted. Seven patients treated in the urology department with soft tissue defects following tumor resection, infection, and dehiscence were included. RESULTS: In all patients, the ALT flap was utilized successfully to reconstruct soft tissue defects up to 450 cm2 in size. All flaps survived. In 1 case, prolonged wound healing was observed. All defects were adequately addressed with no recurrence of dehiscence or fistula formation. CONCLUSIONS: Pedicled perforator flaps represent a valid option for the soft tissue reconstruction of the lower abdomen and perineum when a pedicled rectus abdominis flap is no longer available. This flap is, therefore, a good option in an interdisciplinary approach to soft tissue reconstruction, especially following urologic surgery, which is predominantly performed in the LAPG region.

[Smartphone-based photographic wound documentation improves the quality of medical accounting in orthopedic and plastic surgery]. / Qualitätssteigerung der Abrechnungsprüfung durch Smartphone-basierte Fotodokumentation in der Unfall­, Hand- und plastischen Chirurgie.

BACKGROUND: Photographic documentation of wounds, decubitus ulcers, tumors, open fractures and infections is an important part of digital patient files. It is unclear whether the photographic documentation has an effect on medical accounting with health insurance companies. OBJECTIVE: It was hypothesized that Smartphone-based systematic photographic documentation can improve the confirmation of proceeds-relevant diagnoses and procedures as well as the duration. MATERIAL AND METHODS: Staff in the emergency room, operating theater, outpatient clinic and on the wards were equipped with digital devices (Smartphone, tablet) including a photo-app. Medical accounting with the health insurance companies and identification of all case conferences in which the photographic documentation had effected a change in proceeds were analyzed for 2019 in a retrospective manner. RESULTS: Overall, 372 cases were discussed of which 27 cases were affected by the digital photographic documentation. Photographic documentation was used for clarification of the operative procedure (n = 5), primary diagnosis (n = 10), secondary diagnosis (n = 3), and length of hospitalization (n = 9). An average of 2119 € was negotiated and added per case affected by photographic documentation. Hereby, a level 1 trauma center gained an estimated 65,328 € in revenue. DISCUSSION: The use of Smartphone based photographic documentation can improve the overall quality of patient files and thus avoid loss of revenue. The implementation of digital devices with corresponding software is an important component of the digital structural change in hospitals.

The reverse sural artery flap- How do modifications boost its reliability? A systematic analysis of the literature.

The reverse sural artery flap (RSAF) was first described approximately four decades ago and has since been used frequently for reconstruction of soft tissue defects in the distal part of the leg. Although the popularity of this flap never reached the extent of that of free perforator flaps, it still serves as a reliable alternative. This has been demonstrated by the increased rate of publication on the technique in recent years. The number of authors reporting data has risen up to 20 reports a year. During this time, several new modifications of the flap were inaugurated in order to boost the efficiency and reliability of the flap. The goal of this systematic analysis of the literature was to gain information on the influences of the modifications of the RSAF with regard to consistency and complication rates. An overall survival rate of 95% and a rate of complications of 14% were reported in all the analyzed cases. Some modifications were able to improve flap viability but not at a statistically significant extent. Venous supercharging and the adipofascial variant of the RSAF provided the best results. The RSAF is still a remarkable flap design, especially as a backup solution or in circumstances without a microsurgical skilled surgeon. Further investigation with controlled randomized prospective trials is vital to confirm this finding with more evidence.

[The impact of SARS-CoV-2 restrictions on medical care in Plastic Surgery]. / Die Auswirkungen der SARS-CoV-2-Einschränkungen auf die Patientenversorgung im Fachbereich für Plastische, Rekonstruktive und Ästhetische Chirurgie.

BACKGROUND: To manage the expected COVID-19 patient load major restrictions in in- and outpatient treatment had to be made. Depending on local conditions and order supply differences SARS-CoV-2 restrictions had a massive impact on medical care. To show the impact of plastic surgery on emergency surgery during SARS-CoV-2 pandemic, the amount of surgical emergencies in a single center plastic surgery division were evaluated. METHOD: The number of plastic surgery cases in a university hospital was evaluated during 16.03.2020 to 27.04.2020 and compared with previous years. RESULTS: Due to cancelling of elective surgery the number of cases dropped to 57,3 % of the caseload of previous years. There was no change in ratio of emergency (2020: 56,4 %; 2017-2019: 54,9 %) and urgent (2020: 44,6 %; 2017-2019: 45 %) surgery. No changes in regard to the etiology of trauma cause nor insurance status (occupational insurance/health insurance) were noted. CONCLUSION: Based on the data of this evaluation there is a clear relevance of Plastic Surgery in the setting of general medical care. Even during the pandemic crises a sufficient plastic surgery service is mandatory in a tertiary referral center.

[Local flaps as a last attempt to avoid lower extremity amputation: an overview]. / Lokale Lappenplastiken als letzter Versuch vor der Unterschenkelamputation: eine Übersicht.

BACKGROUND: Soft tissue reconstruction in aged patients is challenging. Free tissue transfer can be carried out in healthy patients with a high success rate despite old age. When free tissue transfer is contraindicated in multimorbid patients, local flaps are often chosen, which are associated with a high complication rate. Such salvage interventions must be selected so that an amputation is not disadvantageously influenced by the selection of the donor site or is even impossible. METHODS: The three distally based local flaps the sural artery flap, peroneus brevis muscle flap and perforator-based propeller flaps are discussed with respect to placement of the donor site as well as wound healing disorders. RESULTS: The sural artery flap is disadvantageous as the donor site because the proximal dorsal calf region is affected, which in the case of a below the knee amputation enables soft tissue covering of the stump. CONCLUSION: If a local flap is to be used as a salvage surgery in an attempt to prevent a below the knee amputation in a patient who is not suitable for free tissue transfer, special emphasis must be placed on the donor site of this flap. The proximal dorsal aspects of the distal calf are required for covering a potential stump and should not be violated by harvesting a local flap.

Inflammation-induced tissue damage mimicking GvHD in human skin models as test-platform for immunotherapeutics.

With cellular products being on the front run there is a rising demand for non-animal-based test platforms to predict, study and treat undesired immunity. Here, we generated human organotypic skin models from human biopsies isolating and expanding keratinocytes, fibroblasts and microvascular endothelial cells finally allowing to seed these components on a collagen matrix or a biological vascularized scaffold matrix in a bioreactor. Afterwards, we were able to induce inflammation-based tissue damage by pre-stimulated mismatched allogeneic lymphocytes and/or inflammatory cytokine containing supernatants histomorphologically mimicking severe graft versus host disease (GvHD) of the skin. The effects could be prevented by the addition of immunosuppressants to the models. Consequently, these models would harbor a promising potential to serve as a test platform for the prediction, prevention and treatment of GvHD. This would also allow functional studies of immune effectors and suppressors including but not limited to allodepleted lymphocytes, gamma-delta T cells, regulatory T cells and mesenchymal stromal cells which would otherwise be limited to animal models. Thus, the current test platform developed with the limitation given that no professional APC are in place could highly reduce animal testing for investigation of novel immune therapies.