24 Hours Ex-vivo Hypothermic Acellular Perfusion of Porcine Forelimb: A 7-day Follow-up Study.

BACKGROUND: One of the limiting factors for vascularized composite allograft (VCA) storage is the short viable ischemic time (4-6 hours). Hypothermic machine perfusion (MP) enables near-physiological preservation, avoiding the deleterious effects of hypoxia and static cooling. This study aims to compare muscle injury after 24-hour acellular perfusion with static cold storage (SCS) in a porcine limb replantation model, examining outcomes for up to 7 days after reperfusion. METHODS: Sixteen procured porcine forelimbs were perfused hypothermic for 24 hours with Histidine-Tryptophan-Ketoglutarate (HTK, n=8) or preserved on ice for 4 hours (SCS, n=8) before orthotopic replantation. Muscle injury was assessed using biochemical markers and muscle biopsies were analyzed using the Histologic Injury Severity Score (HISS). RESULTS: During preservation, limb weight decreased by 2% in the SCS group and increased by 44% in the perfusion group (p<0.001). Twelve limbs (HTK, n=6; SCS, n=6) survived for 7 days. Three days after replantation, increased creatinine kinase levels were observed in the perfusion group (33781 mmol/liter versus 2163 mmol/liter; p<0.001). Mean endpoint HISS was 3.8 (SD 0.7) in the perfusion group and 1.8 (SD 0.7) in the SCS group (p=0.008), mostly due to increased edema (p=0.004). CONCLUSION: 24 hours of hypothermic MP and 4 hours of SCS of VCA demonstrated both minimal degenerated muscle tissue seven days after replantation.

Complications after radial polydactyly surgery: analysis, prevention and management.

Long-term follow-up after surgical correction of patients with radial polydactyly might reveal unexpected or undesired outcomes that are accentuated by growth. It should be stressed that assessment of outcomes differs considerably by the system used. Preoperative examination can elucidate the underlying pathological anatomy of these anomalies and consequently, these anatomical differences should be corrected as much as possible during the first operation to prevent worse outcomes at long-term follow-up. In various long-term studies, the reoperation rate was in the range of 7%-28%, with the most common reasons being deviation, instability, nail deformity and suboptimal appearance. Most unfavourable results occur during growth and are frequently revealed only at longer-term follow-up. Concentration of care to a few centres is advised since these malformations occur in small numbers and experienced surgeons tend to have better results. Consensus on the used assessment system and multicentred studies are essential in future to better understand how we can prevent reoperations.

Superior preservation of capillaries, myofibrils and mitochondria after long-term extracorporeal perfusion of free muscle flaps - A descriptive electron microscopy study.

BACKGROUND: Extracorporeal perfusion (ECP) is a promising technique for prolonged tissue preservation, but might have side effects. For instance, increased radical oxygen species or capillary endothelial damage. OBJECTIVE: To assess ultra-morphological muscle damage during 36-hour ECP of porcine musculocutaneous flaps, hypothesizing that it would delay the onset of damage compared to static cold storage (SCS). METHODS: Bilateral flaps were retrieved from three Dutch Landrace pigs. Three flaps were preserved for 36 hours by hypothermic storage 4-6°C (control group) and three flaps by ECP with cooled University of Wisconsin solution. Muscle biopsies were taken at 0 h, 12 h and 36 h and assessed with transmission electron microscopy. RESULTS: Muscle architecture was best preserved by ECP, with a delayed onset and decreased severity of muscle damage. After 36 hours, damage was two-fold lower in ECP-flaps compared to SCS-flaps. Myofibril architecture was best preserved. Mitochondria were greatly preserved with swelling being the most prominent feature. Capillaries were moderately but differently damaged during ECP, with focal endothelial thinning as opposed to luminal obstruction in SCS-preserved flaps. CONCLUSIONS: This experiment described favourable cellular preservation of skeletal muscle flaps during ECP compared to SCS. Results showed less severe ultra-morphological damage and a later onset of damage.

Ex Vivo Thrombolysis to Salvage Free Flaps Using Machine Perfusion: A Pilot Study in a Porcine Model.

BACKGROUND: Mechanical evacuation of capillary thrombi in free flaps is difficult, and often requires thrombolytic therapy. Utilizing machine perfusion systems, the possibility rises to salvage free flaps ex vivo by administering high doses of thrombolytic agents. The primary aim of this pilot study in a porcine model is to investigate the feasibility of ex vivo thrombolysis using an extracorporeal perfusion machine. METHODS: A model of stasis-induced thrombosis was used in 12 free rectus abdominis flaps harvested from six Dutch Landrace pigs. Compromised flaps were ex vivo perfused with University of Wisconsin preservation solution and treated according to the following study groups: (1) 1 mg of tissue plasminogen activator (t-PA) as additive, (2) 3 mg of t-PA as an additive, and (3) no thrombolytic additive. Microcirculation was assessed using near-infrared fluorescence angiography. RESULTS: Pedicled abdominal flaps were created and thrombus formation was successfully induced. Eleven abdominal flaps were perfused using the modified heart-lung machine setup. Near-infrared fluorescence angiography showed delayed or no filling was noted in the control group. In comparison, the flaps which were perfused with 1 mg t-PA or 3 mg t-PA as additive showed increased fluorescence intensity curves. CONCLUSION: This pilot study in a porcine model presents a reliable and reproductive stasis-induced thrombosis model in free flaps. By adding t-PA to a custom-made extracorporeal perfusion system, the indocyanine green fluorescence intensity curves increased of all flaps that were perfused with different dosages of t-PA as additives, indicating restoration of capillary pressure and microcirculatory inflow.

Ex Vivo Machine Thrombolysis Reduces Rethrombosis Rates in Salvaged Thrombosed Myocutaneous Flaps in Swine.

BACKGROUND: There is a risk for thrombotic complications (2 to 5 percent) associated with microsurgical reconstruction. Current thrombolytic therapy has a salvage rate between 60 and 70 percent, but it is afflicted by bleeding complications (2 to 6 percent). The use of machine perfusion for delivering thrombolytic agents is a new method that could potentially reduce these complications. In this article, the authors compared flap salvage outcomes comparing machine thrombolysis versus a manual flush with tissue plasminogen activator. METHODS: Sixteen bilateral flaps (12 × 9 cm) were dissected from eight female Dutch Landrace pigs (70 kg). Thrombosis was induced in free rectus abdominis flaps by clamping the pedicle's veins for 2 hours. Flaps were either thrombolysed with 2 mg tissue plasminogen activator (1 mg/ml) during 2 hours of machine perfusion (perfusion group; n = 8) or injected intraarterially (manual group; n = 8) before replantation. Near-infrared fluorescence angiography was used to confirm thrombus formation and to assess tissue perfusion; muscle biopsy specimens were analyzed for ischemia/reperfusion injury directly after thrombolysis and 15 hours after replantation. RESULTS: A higher incidence of secondary thrombosis was seen in the manual group compared to the perfusion group ( n = 6 versus n = 0, respectively; p < 0.001), resulting in two complete flap failures. Fifteen hours after replantation, mean fluorescence intensities were 13.0 (95 percent CI, 10.1 to 15.8) and 24.6 (95 percent CI, 22.0 to 27.2) in the perfusion and manual group, respectively ( p < 0.001), and mean muscle injury scores were comparable, measuring 7.5 ± 1.5. CONCLUSION: Two hours of machine thrombolysis of compromised flaps in a porcine model showed higher salvage rates compared to a manual injection with tissue plasminogen activator and reduced the incidence of secondary thrombosis. CLINICAL RELEVANCE STATEMENT: Using machine perfusion systems for ex vivo thrombolysis provides the benefits of local treatment of a composite tissue without the risk of systemic complications and may improve salvage rates and reduce the incidence of secondary thrombosis.

24-hour Perfusion of Porcine Myocutaneous Flaps Mitigates Reperfusion Injury: A 7-day Follow-up Study.

BACKGROUND: Static cold storage is the gold standard of preservation in vascularized composite allotransplantation and allows a preservation time of 4-6 hours. Machine preservation is a promising technique for prolonged preservation; however, studies on extended preservation that compare different preservatives are scarce. This study aims to assess the feasibility of 24-hour acellular perfusion and compares different preservation solutions in a porcine myocutaneous flap replantation model. METHODS: Six harvested bilateral myocutaneous flaps of three Dutch Landrace pigs were perfused hypothermically for 24 hours with University of Wisconsin machine perfusion solution (UW-MPS; n = 2) or histidine-tryptophan-ketoglutarate solution (HTK; n = 2) or preserved on ice for 4 hours (n = 2) before orthotopic replantation. Animals were observed for 7 days after replantation. Skeletal muscle injury was assessed by biochemical markers during perfusion, and muscle biopsies were analyzed for ischemia reperfusion injury directly after preservation and at 1, 3, and 7 days after replantation. RESULTS: Markers of muscle damage varied during perfusion, but decreased overall in both perfusion groups. Flap weight increased 60% and 97% in the HTK-perfused flaps, compared with -6% and -7% in the UW-MPS-perfused flaps after 24 hours. Histopathologic evaluation demonstrated decreased muscle damage in flaps perfused with HTK compared with the UW-MPS-perfused flaps at 1 week after replantation. CONCLUSIONS: Machine perfusion of myocutaneous flaps for 24 hours with subsequent replantation is feasible, but warrants further research. Perfusion with HTK solution seemed to result in better histological outcomes 7 days after reperfusion compared with UW-MPS.

Rectus Abdominis Flap Replantation after 18 h Hypothermic Extracorporeal Perfusion-A Porcine Model.

Cold storage remains the clinical standard for composite tissue preservation but is time-limited. A long ischemia time during surgery will adversely affect postoperative outcomes due to ischemia-reperfusion injury. Extracorporeal perfusion (ECP) seems to be a promising alternative for prolonged preservation, but more evidence is needed to support its use and to identify optimal perfusion fluids. This article assessed musculocutaneous flap vitality after prolonged ECP and compared outcomes after replantation to short static cold storage (SCS). Unilateral musculocutaneous rectus abdominis flaps were raised from 15 pigs and preserved by 4 h SCS (n = 5), 18 h mid-thermic ECP with Histidine-Tryptophan-Ketoglutarate (HTK, n = 5) or University of Wisconsin solution (UW, n = 5). Flaps were replanted and observed for 12 h. Skeletal muscle histology was assessed (score 0-12; high scores equal more damage), blood and perfusate samples were collected and weight was recorded as a marker for oedema. Mean histological scores were 4.0 after HTK preservation, 5.6 after UW perfusion and 5.0 after SCS (p = 0.366). Creatinine kinase (CK) was higher after ECP compared to SCS (p < 0.001). No weight increase was observed during UW perfusion, but increased 56% during HTK perfusion. Following 12 h reperfusion, mean weight gain reduced 39% in the HTK group and increased 24% in the UW group and 17% in the SCS group. To conclude, skeletal muscle seemed well preserved after 18 h ECP with HTK or UW perfusion, with comparable histological results to 4 h SCS upon short reperfusion. The high oedema rate during HTK perfusion remains a challenge that needs to be further addressed.

[The first bilateral hand transplantation in the Netherlands: results after 1 year]. / De eerste dubbelzijdige handtransplantatie in Nederland.

BACKGROUND: Although more than 130 hand-arm transplantations have been performed worldwide, the first Dutch hand transplantation has been performed only recently. This bilateral hand-arm transplantation was performed in June 2019 in the Radboud University Medical Centre, Nijmegen. This report describes the preparation, procedure and 1-year follow-up results. CASE DESCRIPTION: This 44 years-old female patient had an amputation of both lower legs and hands in 2014, following a severe sepsis with peripheral tissue necrosis. The patient was mobile with her leg prostheses at the time of presentation. The loss of hand function, however, formed a continuous invalidation and could not be improved adequately with prosthesis due to the distal amputation level of her hands. CONCLUSION: The total procedure took 24 hours and was successful. Both the aesthetical and functional results were good and are still improving. The patient considered the transplanted hands immediately as her own.

Reconstruction of full thickness wounds using glyaderm in a single-staged procedure.

INTRODUCTION: In large full-thickness skin defects, donor site morbidity limits the available thickness and surface of skin autografts and therefore only split-thickness skin grafts are possible for reconstruction. Dermal equivalents can be added to these split-thickness grafts to acquire an anatomically better skin reconstruction. Glyaderm is a human derived, acellular dermis and up until now has only been used in a two-staged procedure. This report describes results of a case series using Glyaderm and split-thickness skin grafts in a single-staged procedure. METHODS: Glyaderm was introduced in 2017 in Radboudumc (Nijmegen, The Netherlands). Glyaderm and autologous split-skin grafts were simultaneously applied to the wounds. In cases with large wound surfaces or wounds covering highly mobile areas, negative pressure wound therapy was additionally applied. The first ten cases were followed with regular intervals post-operatively, assessing graft take, scar appearance, post-operative wound problems and re-interventions. RESULTS: Patients were aged 3 weeks to 76 years-old. Treated skin surface varied from 1-16% total body surface. Wounds resulted from trauma (n = 4), burns (n = 4) or soft tissue infections (n = 2). Follow-up varied from 4 months to 1.5 years. No complications occurred after surgery. Average take rate was 98%. Two patients had a later re-intervention to further improve the aesthetic appearance of the scarred area. CONCLUSION: Our first results with the application of Glyaderm in a single-staged procedure provided good healing, graft take and scar appearance. Glyaderm was found a suitable dermal substitute in the treatment of full thickness wounds.

Successful 18-h acellular extracorporeal perfusion and replantation of porcine limbs - Histology versus nerve stimulation.

The current standard for composite tissue preservation is static cold storage (SCS) and is limited to 6 h until irreversible muscle damage occurs. Extracorporeal perfusion (ECP) is a promising technique for prolonged preservation, however, functional results have been scarcely researched. This article assessed neuromuscular function and compared results to histological alterations to predict muscle damage after ECP. Forelimbs of twelve Dutch landrace pigs were amputated and preserved by 4 h SCS at 4-6 °C (n = 6) or 18 h mid-thermic ECP with University of Wisconsin solution (n = 6). Limbs were replanted and observed for 12 h. Sham surgery was performed on contralateral forelimbs (n = 12). Histology analysis scored four subgroups representing different alterations (higher score equals more damage). Muscle contraction after median nerve stimulation was comparable between ECP, SCS, and sham limbs (P = 0.193). Histology scores were higher in ECP limbs compared to SCS limbs (4.8 vs. 1.5, P = 0.013). This was mainly based on more oedema in these limbs. In-vivo muscle contraction was well preserved after 18 h ECP compared to short SCS, although histology seemed inferior in this group. Histology, therefore, did not correlate to muscle function at 12 h after replantation. This leads to the question whether histology or neuromuscular function is the best predictor for transplant success.

Management of free flap salvage using thrombolytic drugs: A systematic review.

BACKGROUND: Microvascular free tissue transfer is a reliable method for reconstructive surgery. However, pedicle thrombosis remains a serious complication following free tissue transfer as no consensus has been reached on the optimal management of failing flaps. The purpose of this systematic review is to examine the current evidence on the use of thrombolytic drugs and their effects on microvascular flap salvage rates. METHODS: A systematic literature search was performed using Medline, Embase, and, PubMed databases to identify scientific literature published between January 1987 and January 2019. This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Articles of English language studies reporting on free flap salvage procedures or protocols using thrombolytic drugs were included and reviewed by one author. RESULTS: Of 105 articles screened, 27 studies and case reports were included and qualified for data extraction. Overall, the level of evidence of the current literature is low. Thirteen retrospective studies tried to demonstrate a systemic approach for thrombolysis in flap salvage. The other 14 case reports presented clinical use of thrombolytic drugs to salvage free flaps. None of the thrombolytic agents presented had superior salvage outcomes. CONCLUSION: A review on the current literature did not provide satisfactory and consistent evidence for the optimal management of patients with microvascular thrombosis, since no consensus has been reached on the optimal management of failing flaps. Prospective randomized studies are needed regarding their indications, dosages, and methods of administration, efficacy, and safety.

Ex-vivo perfusion as a successful strategy for reduction of ischemia-reperfusion injury in prolonged muscle flap preservation - A gene expression study.

INTRODUCTION: With the introduction of vascularized composite allotransplantation (VCA) as new surgical technique, the need arose for strategies that could safely prolong graft preservation. Ex-vivo machine perfusion is a promising technique and is currently applied in solid organ transplantation. There is still limited evidence in the field of VCA and free flap transplantation. This gene expression study aimed to assess the degree of ischemia-reperfusion (IR) injury after preservation and replantation of free muscle flaps in a porcine model. MATERIALS AND METHODS: A microarray analysis was first conducted on muscle flaps preserved by ex-vivo perfusion versus cold storage, to select genes of interest for further investigation. The expression of these selected genes was then examined in a muscle flap replantation model after 18 hour ex-vivo perfusion (n = 14) using qRT-PCR. Two preservation solutions were compared to static cold storage: University of Wisconsin-mp (n = 5) and Histidine-Tryptophan-Ketoglutarate solution (n = 5). RESULTS: A selection of 8 genes was made based on micro-array results: Tumor necrosis factor receptor superfamily member 10-A like, Regulator of G-protein signaling 2, Nuclear factor kappa beta inhibitor zeta, Interleukin-1 beta, Fibroblast growth factor 6 and DNA damage-inducible transcript 4, Hypoxia-inducible factor 1-alpha and Caspase-3. The muscle flap replantation experiment compared their expression patterns before and after preservation and replantation and showed overall comparable gene expression between the preservation groups. CONCLUSIONS: The expression of genes related to ischemia, apoptosis and inflammation was comparable between the ex-vivo perfusion and static cold storage groups. These results suggest that ex-vivo perfusion might be a promising technique for 18 hour muscle preservation in terms of decreasing ischemia-reperfusion injury.

Successful Long-term Extracorporeal Perfusion of Free Musculocutaneous Flaps in a Porcine Model.

BACKGROUND: Extracorporeal perfusion is a technique that aims to safely prolong tissue preservation by reducing ischemia-reperfusion injury. Free muscle flaps provide a sensitive research model due to their low ischemic tolerance. However, long-term perfusion of free muscle flaps is scarcely researched. The aim of this study was to compare tissue damage in musculocutaneous flaps during 36 h of extracorporeal perfusion versus static cold storage. MATERIALS AND METHODS: Bilateral free rectus abdominis flaps were harvested from five Dutch Landrace pigs (weight: 53-59 kg). Flaps were treated for 36 h according to the following study groups: (1) cold storage at 4°C-6°C (n = 4), (2) perfusion with histidine-tryptophan-ketoglutarate (HTK) at 8°C-10°C (n = 3), (3) perfusion with University of Wisconsin solution (UW) at 8°C-10°C (n = 3). Perfusion fluid samples (creatinine kinase, blood gas) and biopsies for quantitative polymerase chain reaction were collected at multiple time points. Microcirculation was assessed at 24 h of preservation using indocyanine-green fluorescence angiography. Flap weight was measured at the start and end of the preservation period. RESULTS: Successful and stable perfusion for 36 h was achieved in all perfused flaps. The mean creatinine kinase increase in the perfusion fluid was comparable in both the groups (UW: +43,144 U/L, HTK: +44,404 U/L). Mean lactate was higher in the UW group than in the HTK group (6.57 versus 1.07 mmol/L). There were homogenous and complete perfusion patterns on indocyanine-green angiography in both the perfusion groups, in contrast to incomplete and inhomogeneous patterns during cold storage. Expression of genes related to apoptosis and inflammation was lower in perfused flaps than in the cold storage group. Weight increase was highest in the HTK group (78%; standard deviation [SD], 29%) compared with UW (22%; SD, 22%) and cold storage (0.7%; SD, 4%). CONCLUSIONS: Long-term extracorporeal perfusion of free rectus abdominis flaps is feasible. Outcomes in the perfusion groups seemed superior compared to cold storage. Hypotheses gained from this research need to be further explored in a replantation setting.

Current insights into extracorporeal perfusion of free tissue flaps and extremities: a systematic review and data synthesis.

BACKGROUND: Extracorporeal perfusion is a promising new technique for prolonged preservation of free flaps and extremities; however, uncertainties on perfusion settings and efficacy still exist. No overview of literature is currently available. This review systematically appraised available evidence comparing extracorporeal perfusion to static storage. MATERIALS AND METHODS: An electronic systematic search was performed on June 12, 2016, in MEDLINE and EMBASE. Articles were included when evaluating the effect of extracorporeal perfusion of free flaps or extremities compared to that of a control group. Two independent researchers conducted the selection process, critical appraisal, and data extraction. RESULTS: Of 3485 articles screened, 18 articles were included for further analyzation. One article studied discarded human tissue; others were studies conducted on rats, pigs, or dogs. Perfusion periods varied from 1 h to 10 d; eight articles also described replantation. Risk of bias was generally scored high; none of the articles was excluded based on these scores. Tissue vitality showed overall better results in the perfused groups, more pronounced when perfusing over 6 h. The development of edema was a broadly described side effect of perfusion. CONCLUSIONS: Although tissue vitality outcomes seem to favor extracorporeal perfusion, this is difficult to objectify because of large heterogeneity and poor quality of the available evidence. Future research should focus on validating outcome measures, edema prevention, perfusion settings, and maximum perfusion time for safe replantation and be preferably performed on large animals to increase translation to clinical settings.

Mammaplasty in patients with large areola: Reducing the nipple-areola complex using intra-areolar incisions.

Minimal incision breast reduction techniques resulting in periareolar scars are widely used. However, this technique is less suitable for patients with large areola diameters and relatively small breasts, requiring a modest reduction or lift only. As a result of the large nipple-areola complex larger amounts of skin must be removed in order to resect the complete peripheral areola, increasing the risk of high-riding nipples, breast flattening and incomplete areola resection resulting in a rest on the vertical scar. This report describes a modified technique offering a solution to these problems. In this technique intra-areolar incisions are used to reduce areola size without resecting large volumes of breast tissue and skin. Complete peripheral areolar resection is always possible and high-riding nipples are avoided.

Subscapularis Z-lengthening in children with brachial plexus birth palsy loses efficiency at mid-term follow-up: a retrospective cohort study.

PURPOSE: The aim of this study was to evaluate early and mid-term clinical outcomes after isolated subscapularis Z-lengthening in children with shoulder internal rotation contractures resulting from brachial plexus birth palsy. METHODS: Children with brachial plexus birth palsy treated with subscapularis tendon Z-lengthening from 2001 to 2011 were retrospectively reviewed. Over this period, 31 patients were identified. Primary outcome was improvement in Mallet score after surgery, and secondary outcome measures were active range of motion and Mallet sub-scores. Clinical outcomes were collected at three time intervals: pre-operatively, one-year post-operative and at latest follow-up. RESULTS: After exclusion, 21 patients remained for further analysis. Mean age at surgery was 3.7 years (range, 1.2-8.7), and mean follow-up length was 6.5 years (2.9-9.7). Moderate improvements were found for mean Mallet score, active external rotation, active abduction and hand-to-mouth movement at one year and latest follow-up. However, improvements in active external rotation and Mallet score were not fully maintained at final follow up. CONCLUSION: Isolated subscapularis Z-lengthening is effective at early follow-up, but results are not maintained at mid-term follow-up.

Multilayered Flap Technique: A Method for Delayed Closure of Giant Omphalocele.

Giant omphalocele is a rare, large abdominal wall defect in which the intra-abdominal organs herniate through the umbilical cord and are covered by a sac. Surgical management of giant omphalocele is challenging, and optimal treatment remains controversial. Two generally accepted treatment options are staged closure and delayed closure. Delayed closure takes place after a period of conservative treatment promoting omphalocele sac epithelialization. We present 3 patients treated by a delayed closure technique for ventral hernia repair. In this technique, the epithelialized omphalocele sac and peritoneum are elevated as flaps, which are used to reconstruct the abdominal wall in multiple layers.

No reduction of radiation dose following the introduction of dose-area product measurement in endoscopic retrograde cholangiopancreatography.

BACKGROUND: During radiological examinations such as endoscopic retrograde cholangiopancreatography (ERCP), it is recommended to record the dose-area product (DAP) to reduce the patient's and the physician's exposure to ionizing radiation. However, the effect of DAP measurement on the total radiation dose in ERCP procedures has never been assessed. OBJECTIVES: This study evaluated radiation dose use in ERCP procedures following the introduction of DAP measurement in the endoscopy unit. Also, patient-related, endoscopist-related and procedure-related factors associated with high DAP values were assessed. MATERIALS AND METHODS: All consecutive ERCPs from January 2008 to March 2011 were retrospectively reviewed. The DAP values and demographic-specific and disease-specific parameters were obtained from patient files and ERCP reports. RESULTS: A total of 279 ERCPs was analysed. The median DAP was 1907 cGy cm (range 316-7981). There was no significant decrease in the total radiation dose used in ERCPs following the installation of the DAP-meter in the endoscopy unit. Variables associated with significantly higher DAP values were precut papillotomy [odds ratio (OR) 2.44], hydrostatic balloon dilation (OR 3.56), stone extraction with a basket (OR 5.27) and procedures performed at the weekend (OR 6.43). CONCLUSION: The introduction of DAP measurement during ERCP did not result in a significant decrease in the total radiation dose. Several risk factors associated with a high radiation dose during ERCP procedures were identified, of which precut papillotomy and procedures performed during the weekend have not been described before in the literature. These factors enable endoscopists to more accurately identify patients at an increased risk of high radiation exposure.