Intra-Operative Vascular Injury and Control During Laparoscopic and Robotic Mesh Explantation for Chronic Post Herniorrhaphy Inguinal Pain (CPIP).

INTRODUCTION: Chronic postherniorrhaphy inguinal pain (CPIP) is common following inguinal hernia repair. As even primary minimally-invasive inguinal hernia repairs carry a risk of significant intra-operative bleeding, it is unsurprising that reoperative groin exploration and mesh explantation for chronic post-inguinal herniorrhaphy pain confers an even higher risk of arteriotomy or venotomy due to a distorted anatomy and the presence of adhesions. In this report, we present a single institution's experience with the management of intra-operative vascular injury encountered during minimally invasive groin exploration and mesh explantation for CPIP. MATERIALS AND METHODS: We performed a retrospective consecutive case series study at a single academic center of patients with CPIP who underwent minimally invasive groin exploration and mesh removal during which an iatrogenic arteriotomy or venotomy occurred from September 2015 to September 2020. Descriptive statistics were collected for age, laterality of hernia repair, mean follow-up time, surgical approach (robotic vs. laparoscopic), type of intra-operative vascular injury, vascular control technique, and post-operative complications. RESULTS: Of 196 minimally invasive groin exploration and mesh removal cases, 46 were performed with robotic assistance and 150 were performed using traditional laparoscopy. The overall incidence of intra-operative vascular injury was 43 (22%). Fifteen of 46 (32%) robotic groin exploration and mesh removal cases and 28 of 150 (19%) laparoscopic cases involved vascular control. Three of 15 (20%) robotic cases and 23 of 28 (82%) laparoscopic cases involved a hybrid open inguinal approach to address anterior pathology (neurectomy, anterior mesh removal, hernia repair) or facilitate exposure for vascular repair. The most common site of injury was the inferior epigastric vessels. Other sites included the iliac vein, iliac artery, corona mortis, and accessory obturator vessels. Vascular control techniques included ligation with an energy device or suture, primary suture repair of injured vessel, or bovine pericardium patch angioplasty. All were managed without intra-operative vascular surgery intervention except for one case with extensive calcification that required endarterectomy and angioplasty to improve patency. No cases required conversion to midline laparotomy. Ninety three percent of the cases with large vessel bleeding during laparoscopic-assisted procedures were repaired via an open groin incision, whereas all cases of large vessel bleeding during robotic-assisted procedures were repaired robotically. None of the patients required transfusion. Postoperative complications occurred in 3 patients (7%), 2 (5%) developed hematoma formation requiring surgical evacuation, and 1 (2%) developed ipsilateral iliofemoral deep vein thrombosis (DVT) and underwent peripheral angiography and thrombolysis. CONCLUSIONS: Although minimally invasive groin exploration and mesh explantation for CPIP is technically challenging, it is a safe and effective operation when performed at experienced centers. Iatrogenic vascular injury should be anticipated but can be effectively controlled laparoscopically, robotically, or via a hybrid open inguinal incision without conversion to a midline laparotomy and with low post-operative complication rates.

N3-alkylation during formation of quinazolin-4-ones from condensation of anthranilamides and orthoamides.

Dimethylformamide dimethylacetal (DMFDMA) is widely used as a source of electrophilic one-carbon units at the formate oxidation level; however, electrophilic methylation with this reagent is previously unreported. Reaction of anthranilamide with DMFDMA at 150 °C for short periods gives mainly quinazolin-4-one. However, prolonged reaction with dimethylformamide di(primary-alkyl)acetals leads to subsequent alkylation at N(3). 3-Substituted anthranilamides give 8-substituted 3-alkylquinazolin-4-ones. Condensation of anthranilamides with dimethylacetamide dimethylacetal provides 2,3-dimethylquinazolin-4-ones. In these reactions, the source of the N(3)-alkyl group is the O-alkyl group of the orthoamides. By contrast, reaction with the more sterically crowded dimethylformamide di(isopropyl)acetal diverts the alkylation to the oxygen, giving 4-isopropoxyquinazolines, along with N(3)-methylquinazolin-4-ones where the methyl is derived from N-Me of the orthoamides. Reaction of anthranilamide with the highly sterically demanding dimethylformamide di(t-butyl)acetal gives largely quinazolin-4-one, whereas dimethylformamide di(neopentyl)acetal forms a mixture of quinazolin-4-one and N(3)-methylquinazolin-4-one. The observations are rationalised in terms of formation of intermediate cationic electrophiles (alkoxymethylidene-N,N-dimethylammonium) by thermal elimination of the corresponding alkoxide from the orthoamides. These are the first observations of orthoamides as direct alkylating agents.