Thoracic endovascular aortic repair (TEVAR) in proximal (type A) aortic dissection: Ready for a broader application?

Objective

Thoracic endovascular aortic repair (TEVAR) has demonstrated encouraging results and is gaining increasing acceptance as a treatment option for aortic aneurysms and dissections. Yet, its role in managing proximal aortic pathologies is unknown—this is important because in proximal (Stanford type A) aortic dissections, 10% to 30% are not accepted for surgery and 30% to 50% are technically amenable for TEVAR. We describe our case series of type A aortic dissections treated by using TEVAR.

Effects of the Antioxidants Lycium Barbarum and Ascorbic Acid on Reperfusion Liver Injury in Rats

Objective

Ischemia/reperfusion (I/R) of the rat liver can induce liver injury through mechanisms involving oxidative and nitrosative stresses. In this study we examined the effects of antioxidants Lycium barbarum (LB) and ascorbic acid on I/R-induced liver injury in rats.

Methods

Liver ischemia was induced by clamping the common hepatic artery and portal vein of rats for 40 minutes. Thereafter, flow was restored with reperfusion for 90 minutes. Blood samples collected before ischemia and after reperfusion were analyzed for alanine transaminase (ALT), lactic dehydrogenase (LDH), hydroxyl radical, and nitric oxide (NO) levels. Pharmacologic interventions included administration of ascorbic acid (100 mg/kg, i.p., 1 hour before I/R) or LB, an extract of Gogi berries: 600 mg in 100 mL of drinking water for 2 weeks prior to experimentation.

Results

This protocol resulted in elevation of blood concentrations of NO, hydroxyl radical, ALT, and LDH (P < .001) in the I/R-induced liver injury group. Ascorbic acid significantly attenuated the reperfusion liver injury by attenuating hydroxyl radical (P < .01) and NO (P < .05) release. The LB aggravated I/R-induced liver injury by increasing hydroxyl radical release with no effect on NO release.

Discussion and conclusions

This I/R protocol resulted in oxidative and nitrosative stress and liver injury. Ascorbic acid showed significant protective effects on reperfusion liver injury by attenuating hydroxyl radical and NO release. In contrast, LB aggravated liver injury by increasing hydroxyl radical release.     

The Effects of Exogenous Administration of Human Coagulation Factors Following Pig‐to‐Baboon Liver Xenotransplantation

We sought to determine the effects of exogenous administration of human coagulation factors following pig‐to‐baboon liver xenotransplantation (LXT) using GalT‐KO swine donors. After LXT, baboons received no coagulation factors (historical control, n = 1), bolus administration of a human prothrombin concentrate complex (hPCC; 2.5 mL/kg, n = 2), continuous infusion of hPCC (1.0 mL/h, n = 1) or continuous infusion of human recombinant factor VIIa (1 µg/kg per hour, n = 3). The historical control recipient demonstrated persistent thrombocytopenia despite platelet administration after transplant, along with widespread thrombotic microangiopathy (TMA). In contrast, platelet levels were maintained in bolus hPCC recipients; however, these animals quickly developed large‐vessel thrombosis and TMA, leading to graft failure with shortened survival. Recipients of continuous coagulation factor administration experienced either stabilization or an increase in their circulating platelets with escalating doses. Furthermore, transfusion requirements were decreased, and hepatic TMA was noticeably absent in recipients of continuous coagulation factor infusions compared with the historical control and bolus hPCC recipients. This effect was most profound with a continuous, escalating dose of factor VIIa. Further studies are warranted because this regimen may allow for prolonged survival following LXT.     

Inhibition of nitric oxide can ameliorate apoptosis and modulate matrix protein gene expression in bacteria infected chondrocytes in vitro.

Bacterial infection stimulates nitric oxide (NO) production in chondrocytes. However, the role of NO in chondrocyte apoptosis after infection remains unclear. The purpose of the study was to test if inhibition of NO could ameliorate apoptosis and modulate matrix protein gene expression in bacteria-infected chondrocytes. It was shown that pre-treating chondrocytes with L-NAME (1 mM) significantly decreased the release of NO (from 72 to 14 microM) and the extent of apoptosis (from 52.9% to 18.9%). Pre-treatment with L-NAME also counteracted the bacteria-induced downregulation of Type II collagen (from 26% to 79%) and aggrecan (from 63% to 105%) mRNA levels. Inhibition of NO after the induction of infection could not decrease the extent of apoptosis and modulate matrix protein gene expression. The results of this study support the hypothesis that NO has an important role in bacteria-induced chondrocyte apoptosis. Pre-treatment but not post-treatment could ameliorate the extent of apoptosis and reestablish the cartilage matrix protein gene expression. This study suggests that in addition to NO, other mechanisms may be responsible for the sustained destruction of articular cartilage in the post-infectious arthropathy.     

Preincisional dextromethorphan combined with thoracic epidural anesthesia and analgesia improves postoperative pain and bowel function in patients undergoing colonic surgery

Colonic surgery is associated with severe postoperative pain and postoperative ileus, which contribute to delayed hospital discharge. In previous studies, we demonstrated that IM dextromethorphan (DM) provided preemptive analgesia and improved postoperative pain. The benefit of thoracic epidural anesthesia (TEA) and postoperative epidural analgesia on postoperative pain was well demonstrated. The goal of this study was to investigate the effect of preincisional IM DM combined with intraoperative TEA and postoperative patient-controlled epidural analgesia (PCEA) on pain and bowel function after colonic surgery. Patients were randomized into 3 equal groups to receive: 1) chlorpheniramine maleate (CPM) 20 mg and general anesthesia (CPM-GA); 2) CPM 20 mg and GA combined with TEA (CPM-TEA); or 3) DM 40 mg (containing 20 mg of CPM) and GA combined with TEA (DM-TEA). The CPM, DM, and TEA with lidocaine were administered after GA induction via an IM injection and 30 min before the skin incision. All patients received postoperative PCEA for pain control. Analgesic effects were evaluated for 72 h after surgery using visual analog scale pain scores at rest and moving, time to first PCEA request for pain relief, total PCEA consumption, and the time to first passage of flatus. Statistically significant improvement of postoperative pain and bowel function was observed in the following order: DM-TEA > CPM-TEA > CPM-GA. Compared with the CPM-TEA group, the DM-TEA group averaged 1.6 points lower on first-hour pain scores, 40 min longer to first PCEA request, 15.8 mL less PCEA drug over 72 h, and 14.7 h earlier bowel function (all P < 0.01). We conclude that the combination of preincisional DM (40 mg IM), intraoperative TEA, and postoperative PCEA enhances analgesia and facilitates recovery of bowel function, suggesting possible synergistic interaction with local anesthetics and opioids.     

Simultaneous combined use of flexible ureteroscopy and percutaneous nephrolithotomy to reduce the number of access tracts in the management of complex renal calculi

OBJECTIVE: To present early experience in managing complex renal calculi using a combined ureteroscopic and percutaneous approach, as complex and branched renal calculi often require multiple access tracts during percutaneous nephrolithotomy (PNL), and the combined use of flexible ureteroscopy and PNL has the potential to reduce the inherent morbidity of several tracts. PATIENTS AND METHODS: The study included seven patients (mean age 54 years) with multiple, branched, large-volume renal calculi suitable for management with PNL. Preoperative data, including patient demographics, stone location and stone surface area, were recorded. After informed consent, the patients underwent combined PNL and ureteroscopy in one session. Intraoperative data, including the location of PNL puncture sites, operative duration and complications, were analysed. Stone-free rates were determined by follow-up imaging at 3 months. RESULTS: All patients had either two or more stones in separate locations in the collecting system, or staghorn stones involving multiple calyces. The mean stone burden was 666 mm(2). All patients had only one percutaneous access tract. The mean operative duration was 142 min and the mean blood loss 79 mL. Two patients had small residual stones (< 3 mm), that required ureteroscopic intervention as they failed to pass spontaneously by 3 months after the initial combined procedure. The convalescence was similar to that in our current PNL practice; imaging showed that five of the patients were stone-free. CONCLUSIONS: Combined PNL and ureteroscopic management can effectively reduce the number of percutaneous access tracts which would otherwise be required for managing complex and branched renal calculi, as stones in an unfavourable location relative to the access tract can be relocated and fragmented within easy reach of the single nephrostomy tract. This manoeuvre reduces potential patient morbidity and blood loss but with no significant effect on stone-free rates and operative durations.     

Iatrogenic femoral neuropathy following pelvic surgery: a rare and often overlooked complication--four case reports and literature review

Femoral neuropathy can result from diverse etiologies following abdominal surgery. We describe four cases of postoperative femoral neuropathy after proctological procedures that were carried out at our hospital. The related symptoms developed occultly but eventually impaired patient motor or sensory functions in the lower extremities. When the patient fails to address associated suffering, it is easy for clinicians to neglect this type of morbidity. All patients recovered from neuropathy following timely detection of the disease entity confirmed by electromyography and nerve conduction studies, followed by adequate rehabilitation management. We hypothesize that postoperative femoral neuropathy may be closely related to unsuitable applications of self-retaining retractors, rather than being associated with other factors, such as gender, age, surgery time or body mass index (BMI). Furthermore, we used a literature review to examine the pathophysiology, diagnoses and treatment modalities of femoral neuropathy resulting from inappropriate placement of self-retaining retractors. Based on a thorough comprehension of the femoral nerves anatomical course and meticulous placement of retractor blades, these types of iatrogenic complications may be prevented.