Surgical treatment of substernal thyroid disease

The thyroid surgeon must have a full understanding of the anatomy and surgical approaches to the mediastinum. Although most benign substernal goiters may be removed by a transcervical approach, the surgeon needs to know indications for transclavicular and median sternotomy approaches. When there is direct evidence of extension of thyroid cancer into the mediastinum, the possibility of median sternotomy should be considered. This is certainly mandated when disease extends to the inferior mediastinum. Superior mediastinal node dissection is usually easy to approach transcervically. Unilateral extension of the disease may be accessed readily with a transclavicular approach for most cases. Careful dissection of the recurrent laryngeal nerve as well as parathyroids is essential to diminish postoperative morbidity. The morbidity is a reflection of the experience and technical skills of the surgeon as well as the extent of the disease. The best results for resection of substernal thyroid disease are obtained by the experienced thyroid surgeon, not the occasional operator.     

A novel mutation in the last exon of ATRX in a patient with α-thalassemia myelodysplastic syndrome

Abstract:  We describe a patient with acquired alpha-thalassemia myelodysplastic syndrome (ATMDS). A previously healthy 66-year-old man presented with hemoglobin of 9.3 g/dL, mean corpuscular volume 59 fL, and a bone marrow aspirate with increased erythroid precursors and hypolobulated megakaryocytes. Hemoglobin H inclusions were seen in most red cells after 1% brilliant cresyl blue supravital stain of the peripheral blood. At the molecular level, we identified of a novel mutation in the most 3' exon of the ATRX gene ( C GA→ T GA substitution in codon 2407) resulting in a premature termination codon (p.R2407X). This case provides further evidence for a link between ATRX mutations and ATMDS, and suggests a possible role for the conserved Q-box element in ATRX function.     

Anaesthesia for endovascular treatment of cerebral aneurysms.

Endovascular treatment of cerebral aneuryms is now widely used and has important implications for the neuroanaesthetist. Significant issues include the decision to use general anaesthesia, factors associated with anaesthesia in the interventional radiology suite and treatment of complications. As endovascular treatment is now supported by evidence and established in practice, neuroanaesthetists should be involved in planning these procedures from a process, and individual patient, perspective.     

A prototype retractor system designed to minimize ischemic brain retractor injury: initial observations

The authors have developed and patented a neurosurgical retractor system incorporating an infrared emitter and detector that allows detection of cerebral pulsations. Gentle contact with the surface of cat brains shows cerebral pulsations that correlate with arterial pulse as well as mechanical ventilation. The amplitude of cerebral pulsations decreases with higher retraction pressure and disappears at approximately 20 mmHg. The pressure on the surface of the brain decreased 50% in 5 minutes even though the position of the retractor was maintained constant. The authors postulate that monitoring cerebral pulsation may prove useful in clinical neurosurgery with respect to avoiding excessive retraction, which causes brain damage.     

An optimal three-stage design for phase II clinical trials

A phase II clinical trial in cancer therapeutics is usually a single-arm study to determine whether an experimental treatment (E) holds sufficient promise to warrant further testing. When the criterion of treatment efficacy is a binary endpoint (response/no response) with probability of response p, we propose a three-stage optimal design for testing H₀: p ≤ p₀ versus H₁: p ≥ p₁, where p₁ and p₀ are response rates such that E does or does not merit further testing at given levels of statistical significance (α) and power (1 ? β). The proposed design is essentially a combination of earlier proposals by Gehan and Simon. The design stops with rejection of H₁ at stage 1 when there is an initial moderately long run of consecutive treatment failures; otherwise there is continuation to stage 2 and (possibly) stage 3 which have decision rules analogous to those in stages 1 and 2 of Simon's design. Thus, rejection of H₁ is possible at any stage, but acceptance only at the final stage. The design is optimal in the sense that expected sample size is minimized when p = p₀, subject to the practical constraint that the minimum stage 1 sample size is at least 5. The proposed design has greatest utility when the true response rate of E is small, it is desirable to stop early if there is a moderately long run of early treatment failures, and it is practical to implement a three-stage design. Compared to Simon's optimal two-stage design, the optimal three-stage design has the following features: stage 1 is the same size or smaller and has the possibility of stopping earlier when 0 successes are observed; the expected sample size under the null hypothesis is smaller; stages 1 and 2 generally have more patients than stage 1 of the two-stage design, but a higher probability of early termination under H₀; and the total sample size and criteria for rejection of H₁ at stage 3 are similar to the corresponding values at the end of stage 2 in the two-stage optimal design.     

Salmon farming: occupational health in a new rural industry

The medical hazards of salmon farming can be grouped into thoserelated to marine safety, fish husbandry, fish-farm diving anddisease treatments. The hostile water environment requires thermalprotection and personal buoyancy aids as workers frequentlyfall in the water from boats or cages. Feedstuffs may generaterespirable dust and attract rats, creating a risk of leptospirosis.Musculo-skeletal injuries are common from lifting nets. Fish-farmdiving has particular risks which can be minimized. Organophosphorouspesticides are used to treat sea lice and employees requirehealth surveillance. Fish immunization is required to reducethe incidence of Aeromonas salmonitica. Needlestick injurieswhen using oil-based vaccines are a serious hazard to employees.The occupational health problems of salmon farming are predictableand preventable with primary safety measures. This new industryis safer than land-based agriculture on current evidence.