Minimally invasive lateral approach to the thoracolumbar junction for corpectomy

Diseases that affect the thoracolumbar junction present a unique challenge to the spine surgeon. Various techniques have been described to treat this clinical entity from the anterior, lateral, or posterior direction. These can be associated with significant morbidity due to extensive tissue dissection, blood loss, and postoperative pain leading to a lengthy recovery. The use of a tubular retractor allows the surgeon to minimize tissue dissection and potentially reduce approach-related morbidity while obviating the need for an approach surgeon for exposure. The surgical technique of a minimally invasive lateral approach to the thoracolumbar junction for corpectomy is described in detail and two illustrative patients are presented.     

Mechanistic studies on the drug metabolism and toxicity originating from cytochromes P450

Abstract

Cytochromes P450 are oxidizing enzymes; a few families of cytochromes P450 are implicated in drug metabolism. These enzymatic reactions involve many processes including (i) prodrug to drug conversion, (ii) easy excretion of drug, (iii) generation of reactive metabolites, many of which cause toxicity. In this review, the fundamental biochemical mechanisms associated with the conversion of drugs into the useful or toxic metabolites have been discussed. The mechanisms can be established with the help of many experimental methods like mass spectral analysis, NMR and in vitro analysis etc. Computational methods provide detailed atomic level information, which is generally not available from experimental studies. Thus, the in silico efforts in elucidating the molecular mechanisms are complementary to the known experimental methods and are often clearer (especially in providing 3D information about the metabolites and their reactions). Quantum chemical methods and molecular docking become especially very useful. This review includes five case studies, which explain how the atomic level details were obtained to explore the reaction mechanisms of drug metabolism by cytochromes P450.     

The benefit of curative liver resection with a selective bile duct preserving approach for hepatocellular carcinoma with macroscopic bile duct tumor thrombus

BackgroundHepatocellular carcinoma (HCC) presenting with macroscopic bile duct tumor thrombus (BDTT) is an uncommon event. The role of a curative hepatic resection and associated long-term outcomes remain controversial. In addition the necessity for bile duct resection is still unclear. The aim of this study was to evaluate outcomes of hepatectomy with a selective bile duct preservation approach for HCC with BDTT in comparison to outcomes without BDTT.MethodsA total of 22 HCC with BDTT patients who had undergone curative hepatic resection with a selective bile duct preservation approach at our institute were retrospectively reviewed. These were compared to group of 145 HCC without BDTT patients. The impact of curative surgical resection and BDTT on clinical outcomes and survival after surgical resection were analyzed.ResultsAll HCC with BDTT cases underwent major hepatectomy vs. 32.4% in the comparative group. Bile duct preservation rate was 56.5%. The 1-, 3- and 5-year survival rates of HCC with BDTT patients in comparison to the HCC without BDTT group were 81.8%, 52.8% and 52.8% vs. 73.6%, 55.6% and 40.7% (P=0.804) respectively. Positive resection margin, tumor size ≥5 cm and AFP ≥200 IU/mL were significant risk factors regarding overall survival. However, it is unclear whether presence of a bile duct tumor thrombus has an adverse impact on either recurrence free survival or overall survival.ConclusionsBile duct obstruction from tumor thrombus did not necessarily indicate an advanced form of disease. Tumor size and AFP had greater impact on long-term outcomes than bile duct tumor thrombus. Major liver resection with a selective bile duct preserving approach in HCC with BDTT can achieve favorable outcomes comparable to those of HCC without BDTT in selected patients.     

Pivoting to Telehealth: the HSS Experience,Value Gained,and Lessons Learned

HSS Journal ® -     

History of Spinal Fusion: Where We Came from and Where We Are Going

HSS Journal ® - Spinal fusion surgery is performed all over the world to help patients with cervical and thoracolumbar pathology. As outcomes continue to improve in patients with spine-related...     

δ-Opioid receptors up-regulate excitatory amino acid transporters in mouse astrocytes

Background and Purpose

Astrocytic excitatory amino acid transporters (EAATs) regulate extracellular glutamate concentrations and play a role in preventing neuroexcitotoxicity. As the δ-opioid receptor (DOP receptor) is neuroprotective against excitotoxic injury, we determined whether DOP receptor activation up-regulates EAAT expression and function.

Experimental Approach

We measured mRNA and protein expression of EAAT1, EAAT2 and EAAT3 in cultured mouse astrocytes exposed to a specific DOP receptor agonist (UFP-512) with or without a DOP receptor antagonist, DOP receptor siRNA or inhibitors of PKC, PKA, PI3K, p38, MAPK, MEK and ERK, and evaluated the function of EAATs by measuring glutamate uptake.

Key Results

Astrocytic DOP receptor mRNA and protein were suppressed by DOP receptor siRNA knockdown. DOP receptor activation increased mRNA and protein expression of EAAT1 and EAAT2, but not EAAT3, thereby enhancing glutamate uptake of astrocytes. DOP receptor-induced EAAT1 and EAAT2 expression was largely reversed by DOP receptor antagonist naltrindole or by DOP receptor siRNA knockdown, and suppressed by inhibitors of MEK, ERK and p38. DOP receptor-accelerated glutamate uptake was inhibited by EAAT blockers, DOP receptor siRNA knockdown or inhibitors of MEK, ERK or p38. In contrast, inhibitors of PKA, PKC or PI3K had no significant effect on DOP receptor-induced EAAT expression.

Conclusions and Implications

DOP receptor activation up-regulates astrocytic EAATs via MEK-ERK-p38 signalling, suggesting a critical role for DOP receptors in the regulation of astrocytic EAATs and protection against neuroexcitotoxicity. As decreased EAAT expression contributes to pathophysiology in many neurological diseases, including amyotrophic lateral sclerosis, our findings present a new platform for potential treatments of these diseases.Table of Links

Use of half‐normal saline irrigant with cooled radiofrequency ablation within the great cardiac vein to ablate premature ventricular contractions arising from the left ventricular summit

A 62‐year‐old man was referred to our institution for high‐density, symptomatic premature ventricular contractions (PVCs) with resultant decrease in left ventricular (LV) function having failed prior ablation attempts. Successful, durable ablation of the patient's mid‐myocardial PVC arising from the LV summit region was achieved through the proximal great cardiac vein with ablation depth augmented by use of half‐normal saline irrigant. Though standard ablation of ventricular arrhythmias using normal saline irrigation from the coronary venous system has been well‐reported, this may be of limited value in addressing mid‐myocardial sites of origin. This novel case describes the safe use of cooled radiofrequency ablation with use of half‐normal saline irrigant from the distal coronary sinus as an option to address complex sites of PVC origin such as the LV summit.