Innervation of thumb carpometacarpal joint: implications for diagnostic block and denervation procedures.

INTRODUCTION: Osteoarthritis (OA) of the thumb carpometacarpal (CMC) joint is a common disorder that negatively impacts hand function. Denervation of the thumb CMC joint has emerged as a viable treatment option. However, the innervation pattern of the thumb CMC joint is controversial. Therefore, the objective of this study was to identify the articular branches supplying the thumb CMC joint and to document their relationship to anatomical landmarks to provide the foundation for image-guided diagnostic block and denervation procedures. METHODS: In 10 formalin-embalmed upper limb specimens articular branches supplying the thumb CMC joint were dissected from their origin to termination. A frequency map documenting the number of articular branches was generated. The frequency map enabled visualization and comparison of the relative area of innervation of the thumb CMC joint by each articular branch. RESULTS: The thumb CMC joint received innervation from six nerves. These were the deep branch of ulnar nerve (DBUN), dorsal articular nerve (DAN) of the first interosseus space, thenar branch of median nerve (TBMN), palmar cutaneous branch of median nerve (PCBMN), lateral antebrachial cutaneous nerve (LACN) and superficial branch of the radial nerve (SBRN) and/or their branches. Each nerve was found to innervate different aspects of the joint. The DBUN and DAN were found to innervate the posteromedial aspect of the thumb CMC joint, the TBMN and PCBMN anterior/anteromedial aspects, LACN posterolateral/lateral/anterior aspects and SBRN posterolateral/anterolateral aspects. CONCLUSIONS: The thumb CMC joint was innervated by articular branches originating from the SBRN, DAN, LACN, PCBMN, TBMN and DBUN. The documented anatomical relationships provide the foundation to inform selective diagnostic block and denervation of the thumb CMC joint. Further investigations are needed to assess the clinical implications of the current study.

Anatomical Study of the Innervation of Triangular Fibrocartilage Complex and Distal Radioulnar and Radiocarpal Joints: Implications for Denervation.

PURPOSE: Open and percutaneous denervation is an emerging technique for joint pain. This study investigated the course and distribution of the articular branches innervating the triangular fibrocartilage complex (TFCC), distal radioulnar joint (DRUJ), and radiocarpal joint (RCJ) relative to bony and soft tissue landmarks to guide wrist denervation procedures. METHODS: Fourteen formalin-embalmed specimens were serially dissected to expose the origin, course, and distribution of articular branches innervating the TFCC, DRUJ, and RCJ. Bony and soft tissue landmarks to localize each articular branch were documented and visualized on a 3-dimensional reconstruction of the bones of the distal forearm and hand. RESULTS: The TFCC was innervated by articular branches from the posterior interosseus nerve (10 of 14 specimens), dorsal cutaneous branch of the ulnar nerve (14 of 14 specimens), palmar cutaneous branch of the ulnar nerve (12 of 14 specimens), and medial antebrachial cutaneous nerve (9 of 14 specimens). The DRUJ was innervated by the posterior interosseus nerve (9 of 14 specimens) and anterior interosseus nerve (14 of 14 specimens). The RCJ was innervated by the posterior interosseus nerve (14 of 14 specimens), superficial branch of the radial nerve (5 of 14 specimens), lateral antebrachial cutaneous nerve (14 of 14 specimens), and palmar cutaneous branch of the median nerve (10 of 14 specimens). CONCLUSIONS: Multiple nerves were found to innervate the TFCC, DRUJ, and RCJ. The relationship of anatomical landmarks to specific articular branches supplying the TFCC, DRUJ, and RCJ can inform selective denervation procedures based on the structural origin of pain. CLINICAL RELEVANCE: The detailed documentation of the spatial relationship of the nerve supply to the wrist provides clinicians with the anatomical basis to optimize current, and develop new denervation protocols to manage chronic wrist pain.

The association of thrombin generation with bleeding outcomes in cardiac surgery: a prospective observational study.

BACKGROUND: Cardiac surgery with cardiopulmonary bypass (CPB) is associated with coagulopathic bleeding. Impaired thrombin generation may be an important cause of coagulopathic bleeding but is poorly measured by existing hemostatic assays. We examined thrombin generation during cardiac surgery, using calibrated automated thrombography, and its association with bleeding outcomes. METHODS: We conducted a prospective observational study in 100 patients undergoing cardiac surgery with CPB. Calibrated automated thrombography parameters were expressed as a ratio of post-CPB values divided by pre-CPB values. The association of thrombin generation parameters for bleeding outcomes was compared with conventional tests of hemostasis, and the outcomes of patients with the most severe post-CPB impairment in thrombin generation (≥ 80% drop from baseline) were compared with the rest of the cohort. RESULTS: All 100 patients were included in the final analysis, with a mean age of 63 (12) yr, 31 (31%) female, and 94 (94%) undergoing bypass and/or valve surgery. Post-CPB, peak thrombin decreased by a median of 73% (interquartile range [IQR], 49-91%) (P < 0.001) and total thrombin generation, expressed as the endogenous thrombin potential (ETP), decreased 56% [IQR, 30-83%] (P < 0.001). In patients with ≥ 80% decrease in ETP, 21% required re-exploration for bleeding compared with 7% in the rest of the cohort (P = 0.04), and 48% required medical or surgical treatment for hemostasis compared with 27% in the rest of the cohort (P = 0.04). CONCLUSIONS: Thrombin generation is significantly impaired by CPB and associated with higher bleeding severity. Clinical studies aimed at the identification and treatment of patients with impaired thrombin generation are warranted.

RéSUMé: CONTEXTE: La chirurgie cardiaque avec circulation extracorporelle (CEC) est associée à des saignements sur coagulopathie. L'altération de la génération de thrombine peut constituer une cause importante de saignement sur coagulopathie, mais elle est mal mesurée par les tests d'hémostase existants. Nous avons examiné la génération de thrombine pendant la chirurgie cardiaque à l'aide d'une thrombographie automatisée calibrée ainsi que son association avec les issues hémorragiques. MéTHODE: Nous avons réalisé une étude observationnelle prospective portant sur 100 patients bénéficiant d'une chirurgie cardiaque sous CEC. Les paramètres de thrombographie automatisée calibrée ont été exprimés sous forme du rapport entre les valeurs post-CEC divisées par les valeurs pré-CEC. L'association des paramètres de génération de thrombine pour les issues hémorragiques a été comparée aux tests conventionnels de l'hémostase, et les issues des patients présentant l'altération post-CEC la plus prononcée dans la génération de thrombine (baisse ≥ 80 % par rapport aux valeurs de base) ont été comparées au reste de la cohorte. RéSULTATS: Les 100 patients ont tous été inclus dans l'analyse finale, avec un âge moyen de 63 (12) ans, 31 (31 %) femmes et 94 (94 %) subissant une chirurgie de pontage et / ou une chirurgie valvulaire. Après la CEC, le pic de thrombine a diminué d'une médiane de 73 % (écart interquartile [ÉIQ], 49 à 91 %) (P < 0,001) et la génération de thrombine totale, exprimée en potentiel de thrombine endogène (PTE), a diminué de 56 % [ÉIQ, 30­83 %] (P < 0,001). Chez les patients présentant une diminution ≥ 80 % du PTE, 21 % ont nécessité une nouvelle exploration pour dépister les saignements, comparativement à 7 % dans le reste de la cohorte (P = 0,04), et 48 % ont nécessité un traitement médical ou chirurgical pour l'hémostase, comparativement à 27 % dans le reste de la cohorte (P = 0,04). CONCLUSION: La génération de thrombine est significativement altérée par la CEC et associée à des saignements plus graves. Des études cliniques visant à identifier et à traiter les patients présentant une altération de la génération de thrombine sont recommandées.

Preventing and managing catastrophic bleeding during extracorporeal circulation.

The use of extracorporeal circulation for cardiac surgery and extracorporeal life support poses tremendous challenges to the hemostatic equilibrium given its diametric tendency to trigger hyper- and hypocoagulopathy. The necessity of anticoagulant therapy to counteract the hemostatic activation by the extracorporeal circuitry compounded by unfavorable patient and surgical factors significantly increase the risk of catastrophic bleeding in patients who require extracorporeal circulation. Preoperative measures, such as stratification of high-risk bleeding patients, and optimization of the modifiable variables, including anemia and thrombocytopenia, provide a crude estimation of the likelihood and may modify the risk of catastrophic bleeding. The anticipation for catastrophic bleeding subsequently prompts the appropriate preparation for potential resuscitation and massive transfusion. Equally important is intraoperative prevention with the prophylactic application of tranexamic acid, an antifibrinolytic agent that has promising benefits in reduction of blood loss and transfusion. In the event of uncontrolled catastrophic bleeding despite preemptive strategies, all effort must be centered on regaining hemostasis through surgical control and damage control resuscitation to protect against worsening coagulopathy and end organ failure. When control of bleeding is reinstated, management should shift focus from systemic therapy to targeted hemostatic therapy aimed at the potential culprits of coagulopathy as identified by point of care hemostatic testing. This review article outlines the strategies to appropriately intervene using prediction, prevention, preparation, protection, and promotion of hemostasis in managing catastrophic bleeding in extracorporeal circulation.

Comparative Evaluation of Crystalloid Resuscitation Rate in a Human Model of Compensated Haemorrhagic Shock.

INTRODUCTION: The most effective rate of fluid resuscitation in haemorrhagic shock is unknown. METHODS: We performed a randomized crossover pilot study in a healthy volunteer model of compensated haemorrhagic shock. Following venesection of 15 mL/kg of blood, participants were randomized to 20 mL/kg of crystalloid over 10 min (FAST treatment) or 30 min (SLOW treatment). The primary end point was oxygen delivery (DO2). Secondary end points included pressure and flow-based haemodynamic variables, blood volume expansion, and clinical biochemistry. RESULTS: Nine normotensive healthy adult volunteers participated. No significant differences were observed in DO2 and biochemical variables between the SLOW and FAST groups. Blood volume was reduced by 16% following venesection, with a corresponding 5% reduction in cardiac index (CI) (P < 0.001). Immediately following resuscitation the increase in blood volume corresponded to 54% of the infused volume under FAST treatment and 69% of the infused volume under SLOW treatment (P = 0.03). This blood volume expansion attenuated with time to 24% and 25% of the infused volume 30 min postinfusion. During fluid resuscitation, blood pressure was higher under FAST treatment. However, CI paradoxically decreased in most participants during the resuscitation phase; a finding not observed under SLOW treatment. CONCLUSION: FAST or SLOW fluid resuscitation had no significant impact on DO2 between treatment groups. In both groups, changes in CI and blood pressure did not reflect the magnitude of intravascular blood volume deficit. Crystalloid resuscitation expanded intravascular blood volume by approximately 25%.

Assessment of Liver Remnant Using ICG Clearance Intraoperatively during Vascular Exclusion: Early Experience with the ALIIVE Technique.

Background. The most significant risk following major hepatectomy is postoperative liver insufficiency. Current preoperative assessment of the future liver remnant relies upon assumptions which may not be valid in the setting of advanced resection strategies. This paper reports the feasibility of the ALIIVE technique which assesses the liver remnant with ICG clearance intraoperatively during vascular exclusion. Methods. 10 patients undergoing planned major liver resection (hemihepatectomy or greater) were recruited. Routine preoperative assessment included CT and standardized volumetry. ICG clearance was measured noninvasively using a finger spectrophotometer at various time points including following parenchymal transection during inflow and outflow occlusion before vascular division, the ALIIVE step. Results. There were one case of mortality and three cases of posthepatectomy liver failure. The patient who died had the lowest ALIIVE ICG clearance (7.1%/min versus 14.4 ± 4.9). Routine preoperative CT and standardized volumetry did not predict outcome. Discussion/Conclusion. The novel ALIIVE technique is feasible and assesses actual future liver remnant function before the point of no return during major hepatectomy. This technique may be useful as a check step to offer a margin of safety to prevent posthepatectomy liver failure and death. Further confirmatory studies are required to determine a safety cutoff level.

Cultural schemas for racial identity in Canadian television advertising.

What meanings are attached to race in advertising? We analyze a sample of prime-time Canadian television advertising to identify cultural schemas for what it means to be White, Black, and East/Southeast Asian. Our empirical focus is on food and dining advertising. Through quantitative content analysis of associations between race and food subtypes, we show that there are systematic differences in the types of foods that groups are associated with. Through a qualitative content analysis of the commercials, we illuminate these quantitative patterns and discuss six cultural schemas for racial identity. The schemas allow for both diversity and privilege in the representation of Whites, and poignant contrasts regarding status and emotionality in the narrow representations of the other two groups.