Feasibility of transsphenoidal approach for hypothalamic biopsy based on a radiological evaluation of subchiasmatic corridor dimension.

BACKGROUND: Surgical access to hypothalamic pathologies can be challenging. Recent case series demonstrate that the transsphenoidal approach to the hypothalamus can be safe and effective, however, may not be feasible in all patients. This study aims to investigate the feasibility of the endonasal transsphenoidal suprasellar subchiasmatic (ETSS) approach to the hypothalamus through a radiological evaluation of the subchiasmatic corridor dimension in an adult population. METHODS: A retrospective review of magnetic resonance imaging of the brain was performed on 164 consecutive adult patients at our institution, of which 100 patients were deemed eligible for inclusion. Measurements were obtained at the two narrowest points along the subchiasmatic corridor: the subchiamastic window, which is the face of the subchiasmatic corridor and the midpoint window, which is located in the middle of the subchiasmatic corridor. Based on defined parameters, including the subchasmiatic window width (SW), subchiasmatic window height (SH), midpoint window width (MW), and midpoint window height (MH), patients were dichotomised into groups: patients with subchiasmatic corridor measurements any dimension of less than 3 mm, or patients with dimensions greater than or equal to 3 mm. RESULTS: A total of 72 (72%) of the study population had dimensions of equal to or greater than 3 mm throughout the entirety of the subchiasmatic corridor, making hypothalamic biopsy feasible through the ETSS route for these patients. CONCLUSION: Based on a radiological evaluation of the subchiasmatic corridor dimension in an Australian adult population, the majority of the population are suitable to undergo an endonasal transsphenoidal suprasellar subchiasmatic biopsy of the hypothalamus.

Developments in silicone technology for use in stoma care.

Soft silicone's flexibility, adhesive capacity and non-toxic, non-odourous and hypoallergenic nature have made it an established material for adhesive and protective therapeutic devices. In wound care, silicone is a component of contact layer dressings for superficial wounds and silicone gel sheeting for reducing the risk of scarring, as well as of barriers for incontinence-associated dermatitis. Regarding stoma accessories, silicone is established in barrier films to prevent contact dermatitis, adhesive removers to prevent skin stripping and filler gels to prevent appliance leaks. Until recently, silicone has not been used in stoma appliances flanges, as its hydrophobic nature has not allowed for moisture management to permit transepidermal water loss and prevent maceration. Traditional hydrocolloid appliances manage moisture by absorbing water, but this can lead to saturation and moisture-associated skin damage (MASD), as well as increased adhesion and resultant skin tears on removal, known as medical adhesive-related skin injury (MARSI). However, novel silicone compounds have been developed with a distinct evaporation-based mechanism of moisture management. This uses colloidal separation to allow the passage of water vapour at a rate equivalent to normal transepidermal water loss. It has been shown to minimise MASD, increase wear time and permit atraumatic removal without the use of adhesive solvents. Trio Healthcare has introduced this technology with a range of silicone-based flange extenders and is working with the University of Bradford Centre for Skin Sciences on prototype silicone-based stoma appliance flanges designed to significantly reduce the incidence of peristomal skin complications, such as MARSI and MASD. It is hoped that this will also increase appliance wear time, reduce costs and improve patient quality of life.

Developments in silicone technology for use in stoma care.

Soft silicone's flexibility, adhesive capacity and non-toxic, non-odourous and hypoallergenic nature have made it an established material for adhesive and protective therapeutic devices. In wound care, silicone is a component of contact layer dressings for superficial wounds and silicone gel sheeting for reducing the risk of scarring, as well as of barriers for incontinence-associated dermatitis. Regarding stoma accessories, silicone is established in barrier films to prevent contact dermatitis, adhesive removers to prevent skin stripping and filler gels to prevent appliance leaks. Until recently, silicone has not been used in stoma appliances flanges, as its hydrophobic nature has not allowed for moisture management to permit transepidermal water loss and prevent maceration. Traditional hydrocolloid appliances manage moisture by absorbing water, but this can lead to saturation and moisture-associated skin damage (MASD), as well as increased adhesion and resultant skin tears on removal, known as medical adhesive-related skin injury (MARSI). However, novel silicone compounds have been developed with a distinct evaporation-based mechanism of moisture management. This uses colloidal separation to allow the passage of water vapour at a rate equivalent to normal transepidermal water loss. It has been shown to minimise MASD, increase wear time and permit atraumatic removal without the use of adhesive solvents. Trio Healthcare has introduced this technology with a range of silicone-based flange extenders and is working with the University of Bradford Centre for Skin Sciences on prototype silicone-based stoma appliance flanges designed to significantly reduce the incidence of peristomal skin complications, such as MARSI and MASD. It is hoped that this will also increase appliance wear time, reduce costs and improve patient quality of life.

Developments in silicone technology for use in stoma care.

Soft silicone's flexibility, adhesive capacity and non-toxic, non-odourous and hypoallergenic nature have made it an established material for adhesive and protective therapeutic devices. In wound care, silicone is a component of contact layer dressings for superficial wounds and silicone gel sheeting for reducing the risk of scarring, as well as of barriers for incontinence-associated dermatitis. Regarding stoma accessories, silicone is established in barrier films to prevent contact dermatitis, adhesive removers to prevent skin stripping and filler gels to prevent appliance leaks. Until recently, silicone has not been used in stoma appliances flanges, as its hydrophobic nature has not allowed for moisture management to permit trans-epidermal water loss and prevent maceration. Traditional hydrocolloid appliances manage moisture by absorbing water, but this can lead to saturation and moisture-associated skin damage (MASD), as well as increased adhesion and resultant skin tears on removal, known as medical adhesive-related skin injury (MARSI). However, novel silicone compounds have been developed with a distinct evaporation-based mechanism of moisture management. This uses colloidal separation to allow the passage of water vapour at a rate equivalent to normal trans-epidermal water loss. It has been shown to minimise MASD, increase wear time and permit atraumatic removal without the use of adhesive solvents. Trio Healthcare has introduced this technology with a range of silicone-based flange extenders and is working with the University of Bradford Centre for Skin Sciences on prototype silicone-based stoma appliance flanges designed to significantly reduce the incidence of peristomal skin complications, such as MARSI and MASD. It is hoped that this will also increase appliance wear time, reduce costs and improve patient quality of life.

Leiomyosarcoma: a rare sinonasal malignancy.

Leiomyosarcomas (LMS) are rare sinonasal malignant tumours with 20 cases of nasal LMS previously reported in the literature. An 81-year-old man presented with an incidental left nasal lesion associated with left nasal obstruction and occasional left-sided blood-stained rhinorrhoea. Nasendoscopic examination showed green coloured polyps filling the left nasal cavity with biopsies showing LMS. CT imaging did not show any bony erosion. No metastases were found on positron emission tomography imaging. The patient underwent endoscopic resection and all surgical margins were clear of disease. The patient was declined postoperative radiotherapy, and serial follow-up has not shown any recurrence to date. Nasal LMS are rare sinonasal smooth muscle tumours and symptoms and radiological findings are often non-specific. Therefore, diagnosis is made on histopathological and immunohistochemical analysis. Due to their invasive nature, the treatment of choice is complete surgical resection, with adjuvant therapy reserved for patients with locally advanced or metastatic disease.

Nonoperative management of grade III blunt thoracic aortic injuries.

OBJECTIVE: Blunt thoracic aortic injuries (BTAIs) have historically been treated with open surgery; thoracic endovascular aortic repair (TEVAR), however, is rapidly becoming the standard of care for all grades of injury. Previous studies have shown successful, conservative management of low-grade (I and II) BTAI, but limited literature exists regarding nonoperative management (NOM) for high-grade BTAI. The purpose of this study was to evaluate NOM for grade III BTAI compared with TEVAR. METHODS: There were 75 patients diagnosed with BTAI between January 2004 and June 2015. Of these, 40 were excluded for different grades of BTAI (17), death before any treatment (6), and need for urgent open repair (17). The remaining 35 patients were divided into two groups by treatment approach: NOM (n = 18) and TEVAR (n = 17). Primary end points were complications and mortality. The secondary end point was difference in pseudoaneurysm and aortic diameter measurements between groups. RESULTS: The groups of patients were similar in age, gender, Injury Severity Score, length of stay, in-hospital mortality, and hospital-associated complications. There were four TEVAR-related complications: graft involutions (2), type I endoleak (1), and distal embolization (1). All TEVAR-related complications required either an adjunctive procedure at the time of the primary procedure or an additional procedure. No patients from the NOM group required operative intervention. There were seven in-hospital mortalities: two in the TEVAR group (11.8%) and five in the NOM group (27.8%; P = .402). One death in the NOM group was related to aortic disease. Follow-up computed tomography imaging revealed similar aortic-related outcomes between groups, with a high proportion showing resolved or improved aortic injury (NOM, 87.5%; TEVAR, 92.9%; P = .674). Initial computed tomography imaging showed similar aortic diameters between groups. The average diameter of the aorta distal to the subclavian artery was 22.6 mm in the NOM group vs 22.8 mm in the TEVAR group (P = .85). The average maximum diameter of the pseudoaneurysm was 30.1 mm in the TEVAR group and 29.9 mm in the NOM group (P = .90). The average ratio of diameter of the pseudoaneurysm to diameter of the aorta distal to the subclavian artery was 1.32 for the TEVAR group and 1.33 for the NOM group (P = .85). CONCLUSIONS: The natural history of grade III BTAIs is not well described. This study suggests that observation and NOM of grade III BTAI may be a reasonable therapeutic option in selected patients. It also speaks to the need for further delineation of the natural history of this injury. Serial imaging and long-term follow-up are necessary to monitor the progression of the pseudoaneurysm.

Distinct roles of L- and T-type voltage-dependent Ca2+ channels in regulation of lymphatic vessel contractile activity.

Lymph drainage maintains tissue fluid homeostasis and facilitates immune response. It is promoted by phasic contractions of collecting lymphatic vessels through which lymph is propelled back into the blood circulation. This rhythmic contractile activity (i.e. lymphatic pumping) increases in rate with increase in luminal pressure and relies on activation of nifedipine-sensitive voltage-dependent Ca(2+) channels (VDCCs). Despite their importance, these channels have not been characterized in lymphatic vessels. We used pressure- and wire-myography as well as intracellular microelectrode electrophysiology to characterize the pharmacological and electrophysiological properties of L-type and T-type VDCCs in rat mesenteric lymphatic vessels and evaluated their particular role in the regulation of lymphatic pumping by stretch. We complemented our study with PCR and confocal immunofluorescence imaging to investigate the expression and localization of these channels in lymphatic vessels. Our data suggest a delineating role of VDCCs in stretch-induced lymphatic vessel contractions, as the stretch-induced increase in force of lymphatic vessel contractions was significantly attenuated in the presence of L-type VDCC blockers nifedipine and diltiazem, while the stretch-induced increase in contraction frequency was significantly decreased by the T-type VDCC blockers mibefradil and nickel. The latter effect was correlated with a hyperpolarization. We propose that activation of T-type VDCCs depolarizes membrane potential, regulating the frequency of lymphatic contractions via opening of L-type VDCCs, which drive the strength of contractions.

Electrophysiological properties of rat mesenteric lymphatic vessels and their regulation by stretch.

BACKGROUND: In mammals, lymph is propelled centrally primarily via the phasic contractions of collecting lymphatic vessels, known as lymphatic pumping. Electrophysiological studies conducted in guinea pig and sheep mesenteric lymphatic vessels indicate that contractions are initiated in the lymphatic muscle by nifedipine-sensitive action potentials (APs). Lymphatic pumping is highly sensitive to luminal fluid loading and the mechanical properties of this stretch-induced pumping have been consistently studied, in particular in rat mesenteric lymphatic vessels. However, membrane potential (Vm) and the electrophysiological events underlying stretch-induced lymphatic pumping have not been investigated in the rat. The aim of this study was thus to examine the properties of rat mesenteric lymphatic muscle Vm under resting conditions and to assess changes in Vm caused by distension. METHODS AND RESULTS: Lymphatic muscle Vm was measured with sharp intracellular microelectrodes either in unstretched conditions or under isometric tension provided by a wire-myograph. In unstretched vessels, Vm was -48 ± 2 mV (n=30). APs (amplitude ∼25 mV) were observed at a frequency of ∼8/min and were abolished by nifedipine. Under isometric tension, Vm was less polarized (-36 ± 1 mV, n=23), even at minimum tension. Increase in tension led to increase in contraction strength and contraction/AP frequency, while Vm was slightly hyperpolarized and AP amplitude not markedly altered. CONCLUSIONS: In our experimental conditions, rat lymphatic muscle has electrophysiological characteristics similar to that in other species. It responds to an increase in isometric tension with an increase in AP frequency, but resting Vm is not significantly affected.

Lymphoma of the trigeminal nerve--the need for histological diagnosis.

CNS lymphoma involving the trigeminal nerve is a rare condition which presents as a cavernous sinus lesion. It may mimic the radiological appearance of other lesions, and biopsy is essential before considering empirical radiotherapy for lesions in this region. We report the radiological, histopathological and operative findings of a primary non Hodgkin B cell lymphoma involving the trigeminal nerve.

Mechanisms of VIP-induced inhibition of the lymphatic vessel pump.

Lymphatic vessels serve as a route by which interstitial fluid, protein and other macromolecules are returned to the blood circulation and immune cells and antigens gain access to lymph nodes. Lymph flow is an active process promoted by rhythmical contraction-relaxation events occurring in the collecting lymphatic vessels. This lymphatic pumping is an intrinsic property of the lymphatic muscles in the vessel wall and consequent to action potentials. Compromised lymphatic pumping may affect lymph and immune cell transport, an action which could be particularly detrimental during inflammation. Importantly, many inflammatory mediators alter lymphatic pumping. Vasoactive intestinal peptide (VIP) is a neuro- and immuno-modulator thought to be released by nerve terminals and immune cells in close proximity to lymphatic vessels. We demonstrated the presence of the peptide in lymphatic vessels and in the lymph and examined the effects of VIP on mesenteric collecting lymphatic vessels of the guinea pig using pharmacological bioassays, intracellular microelectrode electrophysiology, immunofluorescence and quantitative real-time PCR. We showed that VIP alters lymphatic pumping by decreasing the frequency of lymphatic contractions and hyperpolarizing the lymphatic muscle membrane potential in a concentration-dependent manner. Our data further suggest that these effects are mainly mediated by stimulation of the VIP receptor VPAC2 located on the lymphatic muscle and the downstream involvement of protein kinase A (PKA) and ATP-sensitive K⁺ (KATP) channels. Inhibition of lymphatic pumping by VIP may compromise lymph drainage, oedema resolution and immune cell trafficking to the draining lymph nodes.

Otogenic cranial base osteomyelitis: a proposed prognosis-based system for disease classification.

OBJECTIVES: To review the presentation, microbiology, and long-term results of treating otogenic cranial base osteomyelitis to develop a prognosis-based disease classification system. PATIENTS AND METHODS: Thirty-eight patients with otogenic cranial base osteomyelitis treated between 1989 and 2002 were studied. Patient demographics, presentation, pathogens, details of therapy, and disease-specific survival were recorded. Patients were stratified using Technetium-99 single-photon emission computerized tomography (SPECT) at presentation into 4 grades: I, mild uptake; II, focal mastoid/temporal bone uptake not reaching midline; III, petrous temporal bone uptake reaching midline; and IV, uptake crossing midline, involving the contralateral temporal bone. Actuarial analysis was used to identify prognostic factors. RESULTS: There were 27 men. The average age at presentation was 65 +/- 16 years (range, 19-95 yr). The median age-adjusted Charlson comorbidity score was 5, and 63% of patients were diabetic. The most common presenting symptoms were pain and otorrhea, and 8 patients had cranial nerve neuropathy. Pseudomonas aeruginosa was the most common bacterial pathogen (n = 28; 74%), and 9 patients had fungal or mixed infections. On average, antibiotics were administered for 161 days, and 6 patients had concomitant surgery. The average follow-up was 33 months, and 3-year disease-specific survival was 76%. Univariate predictors of survival were the SPECT grade, fungal/mixed infections, Charlson score, immune compromise, and cranial nerve neuropathy. The only independent predictor of survival on multivariate Cox regression was the SPECT stage at presentation. CONCLUSION: Cranial base osteomyelitis is associated with significant morbidity and mortality and requires prolonged treatment. Long-term outcome can be predicted from the initial SPECT scan.