Is there a role for routine laryngoscopy before and after parathyroid surgery?

INTRODUCTION: Recurrent laryngeal nerve (RLN) palsy is a potential complication of parathyroid surgery with significant morbidity and a cause of medico-legal litigation. Peri-operative laryngoscopy to assess RLN function helps identify a vocal cord palsy and guide management. The value of its routine use in asymptomatic patients is however unclear. The low risk of permanent palsy, rarity of true asymptomatic palsy and costs, discomfort and inconvenience to patients are arguments against routine laryngoscopy. This study assessed the results of routine laryngoscopy in patients having parathyroid surgery for primary hyperparathyroidism (PHPT). METHODS: All patients having parathyroid surgery for PHPT (exclusion: re-do surgery and concurrent thyroidectomy) over a 3-year period were included from a tertiary endocrine surgical unit. Data on voice-related outcomes and pre- and post-operative laryngoscopy, including its local cost, were collected and analysed. RESULTS: Of 189 patients who underwent parathyroid surgery, 66 had a unilateral neck exploration. The incidence of vocal cord palsy was 0.5% (1 in 186 patients) and 1.7% (3 in 179 patients) for pre- and post-operative laryngoscopy respectively. The single patient with pre-operative cord palsy was asymptomatic. Of the three with post-operative cord palsy, two were temporary and symptomatic and one was asymptomatic. In the region, the clinical commissioning group was charged £127.00 per laryngoscopy, amounting to £46,736.00 for the whole cohort. CONCLUSIONS: The rare nature of vocal cord palsy suggests laryngoscopy is not necessary for patients having surgery for PHPT. It may be reserved for patients with voice change and those having re-operative or concomitant thyroid surgery.

Effect of doping on the intersubband absorption in Si- and Ge-doped GaN/AlN heterostructures.

In this paper, we study band-to-band and intersubband (ISB) characteristics of Si- and Ge-doped GaN/AlN heterostructures (planar and nanowires) structurally designed to absorb in the short-wavelength infrared region, particularly at 1.55 µm. Regarding the band-to-band properties, we discuss the variation of the screening of the internal electric field by free carriers, as a function of the doping density and well/nanodisk size. We observe that nanowire heterostructures consistently present longer photoluminescence decay times than their planar counterparts, which supports the existence of an in-plane piezoelectric field associated to the shear component of the strain tensor in the nanowire geometry. Regarding the ISB characteristics, we report absorption covering 1.45-1.75 µm using Ge-doped quantum wells, with comparable performance to Si-doped planar heterostructures. We also report similar ISB absorption in Si- and Ge-doped nanowire heterostructures indicating that the choice of dopant is not an intrinsic barrier for observing ISB phenomena. The spectral shift of the ISB absorption as a function of the doping concentration due to many body effects confirms that Si and Ge efficiently dope GaN/AlN nanowire heterostructures.

Effect of doping on the far-infrared intersubband transitions in nonpolar m-plane GaN/AlGaN heterostructures.

This paper assesses the effects of Si doping on the properties of nonpolar m-plane GaN/AlGaN quantum wells (QWs) designed for intersubband (ISB) absorption in the far-infrared spectral range. For doping levels up to 3 × 10(12) cm(-2), structural analysis reveals uniform QWs with abrupt interfaces and no epitaxially induced defects. Cathodoluminescence spectroscopy confirms the homogeneity of the multiple QWs along the growth direction. Increasing the doping density in the QWs from 1 × 10(11) cm(-2) to 3 × 10(12) cm(-2) induces a broadening of the photoluminescence as well as a reduction of the exciton localization energy in the alloy. Also, enhancement of the ISB absorption is observed, along with a blue shift and widening of the absorption peak. The magnitude of the ISB absorption saturates for doping levels around 1 × 10(12) cm(-2), and the blue shift and broadening increase less than theoretically predicted for the samples with higher doping levels. This is explained by the presence of free carriers in the excited electron level due to the increase of the Fermi level energy.

Nonpolar m-plane GaN/AlGaN heterostructures with intersubband transitions in the 5-10 THz band.

This paper assesses intersubband (ISB) transitions in the 1-10 THz frequency range in nonpolar m-plane GaN/AlGaN multi-quantum-wells deposited on free-standing semi-insulating GaN substrates. The quantum wells (QWs) were designed to contain two confined electronic levels, decoupled from the neighboring wells. Structural analysis reveals flat and regular QWs in the two perpendicular in-plane directions, with high-angle annular dark-field scanning transmission electron microscopy images showing inhomogeneities of the Al composition in the barriers along the growth axis. We do not observe extended structural defects (stacking faults or dislocations) introduced by the epitaxial process. Low-temperature ISB absorption from 1.5 to 9 THz (6.3-37.4 meV) is demonstrated, covering most of the 7-10 THz band forbidden to GaAs-based technologies.

Postoperative parathyroid hormone (PTH) is equivalent to perioperative PTH drop in predicting postsurgical hypoparathyroidism.

INTRODUCTION: Postoperative surgical hypoparathyroidism (PoSH) following thyroid surgery is an established complication. Several predictive factors have been identified including perioperative parathyroid hormone (PTH) levels. The aim of the study is to compare the drop in perioperative PTH to postoperative day 1 PTH in predicting hypocalcaemia and hypoparathyroidism. METHODS: Records of consecutive patients who had either total or completion thyroidectomy with or without central neck dissection in a 3-year period in a single thyroid surgery unit were accessed to retrieve data on demographics, pathology, surgery, perioperative biochemistry and management. RESULTS: Of 295 included patients, there were 227 (76.9%) females. Forty-five (15.3%) had completion thyroidectomy, and the rest had total thyroidectomy. Seventy-eight (26.4%) had concomitant central neck dissection. Sixty-four (21.7%) had hypocalcaemia on the day after surgery. Hypoparathyroidism persisted in 10.5% of patients at 6 months. Both day 1 PTH and a drop in PTH predicted day 1 hypocalcaemia (p < 0.001) and 6-month hypoparathyroidism (p < 0.001). The area under the receiver operating characteristic (ROC) curves for day 1 PTH and drop in PTH for the prediction of day 1 hypocalcaemia (0.729 vs 0.726, respectively) and for 6-month hypoparathyroidism (0.964 vs 0.958, respectively) were similar, albeit slightly better for day 1 PTH. CONCLUSIONS: Day 1 PTH is equivalent to (if not better than) drop in PTH in predicting short- and long-term PoSH. Preoperative PTH measurements may not be needed in the detection and/or management of PoSH after thyroid surgery.

Characterization of materials eliciting foreign body reaction in stapled human gastrointestinal anastomoses.

BACKGROUND: Staples are made of titanium, which elicits minimal tissue reaction. The authors have encountered foreign body reaction associated with stapled human gastrointestinal anastomoses, although the literature has no reports of this. The aim of this study was to identify the refractile foreign materials causing this reaction. METHODS: Histological sections were taken from 14 gastrointestinal specimens from patients with a history of a stapled anastomosis within the specimen excised. These were reviewed by light and polarization microscopy. Scanning electron microscopy and energy dispersive X-ray analysis were carried out on these sections, staples and stapler cartridges used for gastrointestinal surgery. RESULTS: Foreign bodies rich in fluorine were found in three patients, and those rich in carbon in 12. Other elements identified included oxygen, calcium, sodium, potassium, magnesium, aluminium and silicon. One specimen was found to contain titanium with no surrounding foreign body reaction. Stapler cartridges contained carbon, oxygen, fluorine, calcium, sodium, potassium, magnesium, aluminium, silicon and traces of titanium. Staples were composed of pure titanium with some fibrous material on the surface containing elements found in stapler cartridges. CONCLUSION: The presence of foreign body reaction was confirmed in stapled human gastrointestinal anastomoses. The source of refractile materials eliciting this reaction was the stapler cartridges.

Modification, validation and implementation of a protocol for post-thyroidectomy hypocalcaemia.

Introduction The management of post-thyroidectomy hypocalcaemia should facilitate early discharge, and reduce risks of hypocalcaemia, readmission and treatment related hypercalcaemia. This paper describes the implementation, evaluation and revision a protocol for the optimal management of this condition. Methods Day 1 parathyroid hormone (PTH) measurements in addition to calcium measurements were commenced following review of the unit's outcomes and literature on post-thyroidectomy hypocalcaemia. Outcomes from a three-year cohort of patients undergoing thyroid surgery helped amend this protocol (revision 1) to reduce biochemical tests, stipulate the need, nature and dose of vitamin D/calcium supplements, and encourage early discharge. This was further validated over seven months to assess compliance, episodes of hyper and/or hypocalcaemia after discharge, readmissions and need for treatment changes. Further revisions were made (revision 2) and implemented. Results The temporary and long-term postoperative hypocalcaemia rates were 29.1% and 3.2% respectively. Repeat calcium measurements on the first day altered management in only 1.4% of cases. The revised protocol was adhered to in 90% of cases. One patient had hypocalcaemia (due to non-compliance) and one had hypercalcaemia. Revision 2 involved reducing the dose of calcium. Conclusions This is a good example of a unit protocol for post-thyroidectomy hypocalcaemia being developed and modified on the basis of the literature and local experience. Day 1 PTH and calcium levels determine the need for treatment and frequency of follow-up visits, facilitate early discharge, reduce risk of over and/or undertreatment, and are good indicators of permanent hypocalcaemia.

Detachable functional focused rigidity cast for metatarsal fractures.

This article aims to assess whether a detachable functional focused rigidity cast can be used as a one-off definitive treatment for proximal 5th metatarsal fractures. A prospective trial was carried out over a 2-year period. Forty-one patients with proximal 5th metatarsal fractures (tuberosity and Jones) were recruited and treated with a detachable focused rigidity cast after appropriate consent. Of the 39 patients with follow-up, six had a Jones fracture and 33 had tuberosity fractures. All 33 patients with tuberosity fractures achieved clinical union within 4-5 weeks (mean of 4.2 weeks). Four of the six patients with Jones fractures achieved clinical union in 8-12 weeks. One achieved union in 14 weeks and one underwent open reduction and internal fixation for delayed union. There were no complications related to the cast. The results support the use of a detachable focused rigidity cast as a one-off definitive treatment of tuberosity fractures of the 5th metatarsal. However, all the Jones fractures and the diaphyseal fractures should be referred to an orthopaedic team for further management.

SPECT resolution and uniformity improvements by noncircular orbit.

A noncircular orbit implemented by a combination of rotational and translational motions in single photon emission computed tomography improves significantly the image resolution and uniformity. The former is realized by closer access of the detector to the object at each projection angle, and the latter by suppression of ring artifacts through the shifts in the distance between the centers of detector and object. This has been demonstrated by comparing the SPECT images for an elliptical orbit of 40 cm X 30 cm with the equivalent circular orbit of 40 cm diameter, performed by SPECT system with a high resolution collimator. Resolution FWHM improvements were 1.5-2.5 mm. Lesion contrast improved by a factor of 2.8 for a nonradioactive rod of 6 mm diam. In phantom images, the elliptical orbit showed better definition of lesion shape, sharper edge response, and clearly increased detectability. Translational motion reduced ring artifacts, particularly near the image center.

Performance evaluations of recent wide field scintillation gamma cameras.

Performance characteristics of four recent wide field scintillation gamma cameras were evaluated for 140-keV gamma imaging. Parameters measured included intrinsic spatial resolution, energy resolution, uniformity and linearity distortion, and count-rate capability and its influence on the spatial resolution. The system performance of the cameras was compared with representative parallel-channel collimators in terms of spatial resolution and relative sensitivity. Visual imaging comparisons of each camera system were performed by taking images of Rollo phantom containing four different lesion sizes, with four different contrast ratios, for equal imaging time.

Lesion detection with single-photon emission computed tomography (SPECT) compared with conventional imaging.

We have evaluated analytically and experimentally the effectiveness of both conventional nuclear medicine imaging and single-photon emission computed tomography (SPECT) imaging to detect small photon-deficient areas (approximately the size of the system's resolution) with a relatively uniform background. The experimental model is based on the Tc-99m sulfur colloid study of the liver. The experimental data were obtained from a liver phantom containing two small photon deficient areas, nominally 1 and 1.5 cm in diameter. The liver phantom was placed in a water-filled Alderson body phantom and scanned with the cold defects located both centrally and peripherally. Lesion image contrast for both conventional and SPECT imaging is proportional to the lesion uptake ratio and is degraded by the system's finite spatial resolution and Compton-scattered photons. However, for conventional imaging the contrast is significantly degraded by the effect of radionuclide superposition (as modified by attenuation), while for SPECT imaging the contrast is essentially independent of these effects. This results in a significant increase in lesion-to-background contrast with SPECT as compared with conventional imaging. The measured SPECT image contrasts for the 1- and 1.5-cm areas of low uptake averaged more than five times the measured image contrasts for the conventional system.

Optimized collimators for scintillation cameras.

The use of commerically available tantalum or lead tubes permits convenient fabrication of collimators optimized for specific imaging studies.

Comparison of Ga-67 citrate images obtained with rectilinear scanner and large-field Anger camera.

Two methods for Ga-67 citrate imaging were compared on 20 patients. Scans were performed using approximately equal procedure time with two instruments: (A) a dual 5-in. rectilinear scanner with medium-energy collimator, with a single window spanning both the 93-keV and the 185-keV spectral peaks; and (B) a large-field (15-in. diam) Anger camera equipped with moving table, medium-energy collimator, and three windows covering the 93-keV, 185-keV, and 300-keV peaks separately. Sixteen abnormal sites and 24 normal sites were selected for comparison. Each site was evaluated by four physicians experienced in interpreting Ga-67 citrate images. The observers performed significantly better using the images obtained with the large-field camera (three windows) than with the dual 5-in. scanner (single window).

Medical Positron Imaging with a Dense Drift Space MultiWire Proportional Chamber.

A multiplanar positron camera is proposed, made of six MWPC modules, arranged to form the lateral surface of a hexagonal prism. Each 50 x 50 cm(2) module has a single MWPC sandwiched by two 2-cm thick lead glass tube converters. The experimental results for a 15 x 15 cm(2) test module are reported. For 511 keV gamma-rays incident almost perpendicular onto a 1.0-cm thick converter, a detection efficiency of 4.3%, a time resolution of 130 ns (FWHM) and a spatial resolution of 2.8 mm (FWHM) have been measured with a standard Argon-Methane (70-30) mixture at 1.2 atm. The chamber may also be operated in high resolution mode: 1.2-mm (FWHM) spatial resolution has been measured at a 50% lower efficiency. The use of fast delay lines (specific delay 8 ns/cm) for the position read-out ensures a high rate capability. The expected performance of the six-module MWPC camera is discussed and compared with that of a BGO crystal ring camera. The MWPC solution seems very attractive not only for its low cost and simplicity of construction, but also for its fully three-dimensional imaging capability.

Truncation artifact reduction in transmission CT for improved SPECT attenuation compensation.

Transmission computed tomography (TCT) has been shown to be an accurate method of acquiring non-uniform attenuation maps for single-photon emission computed tomography (SPECT) attenuation compensation. One commonly encountered problem, especially for convergent beam geometries, is image truncation. We describe two methods for reducing associated truncation artifacts, with the goal of improving SPECT attenuation compensation without unduly increasing imaging or reconstruction times: (i) the two-scan method, which reduces the degree of truncation by combining two short-duration, patient-shifted scans, and (ii) a quantitative extrapolation method, which fills in truncated projections accounting for the correct amount of attenuating medium in the slice. The methods are evaluated by imaging two phantoms on a fan beam TCT system. Projection sets are truncated to various degrees with software, and reconstructed images are compared to both untruncated filtered backprojection and iterative reconstructions of truncated data. A fundamental analysis of SPECT attenuation factors is performed, and attenuation compensation of a cardiac insert is analysed. Results indicate the two-scan method can effectively reduce the degree of truncation in many cases, and the quantitative extrapolation method greatly improves SPECT attenuation compensation over using truncated maps.

Cyanide exposure affects the production and excretion of ammonia by the mudskipper Boleophthalmus boddaerti.

The concentrations of ammonia in the plasma of the mudskipper Boleophthalmus boddaerti exposed to cyanide for 1-6 days were significantly greater than the respective values of the controls. This was due to an increase in the production of NH3 in the muscle and an increase in the retention of NH3 and/or NH4+ in the blood of the cyanide-exposed fish when compared to controls. Cyanide exposure significantly increased the specific activity of muscle AMP deaminase. Since adenylosuccinate synthetase and lyase were also present in the muscle, exposure to cyanide might increase the production of NH3 from the catabolism of purine nucleotides. B. boddaerti exposed to cyanide excreted significantly less ammonia than the control fish. Results indicate changes in the permeability of the epithelial surfaces of the cyanide-exposed fish to NH3 and/or NH4+. Since the tissues and organs needed time to activate the inducible cyanide detoxification mechanisms, the increase in the production of NH3 might be an important defensive mechanism for B. boddaerti during the early phase of cyanide exposure.

Morbidity in Alagille syndrome in 6 Malaysian children.

We retrospectively studied the records of 6 Malaysian children who were diagnosed with Alagille Syndrome (AGS) according to this criteria from January 1999 to January 2001, at the Institute of Paediatrics, Kuala Lumpur Hospital. Four patients (66%) had a positive family history. Thirteen individuals (6 patients and 7 relatives) were diagnosed with AGS in these 5 families. Only 6/13 (46%) of them presented with liver involvement. All 6 patients presented with typical facies and cholestasis (100%). Three (50%) presented with portal hypertension (PHT) with synthetic liver dysfunction (1 died), 1/6 (17%) have PHT and normal synthetic liver function. Two have cleared their jaundice but have biochemical evidence of hepatitis and hepatomegaly, four have congenital heart disease 5/6 posterior embryotoxon, 2/6 butterfly vertebrae, 4/6 hyperlipidaemia and 4/6 failure to thrive. One patient has a Jagged-1 gene disruption at the translocation breakpoint locus 20p12.3 2n = 46,XX,t(12.20) (q22, p12.3). 5/6 (83%) are still alive. Two-thirds of our patients developed chronic liver disease by 3 years of age. Two-thirds of the index patients have a family history. Only 46% of individuals in these families have clinical evidence of liver involvement. Mortality depends on cardiac/renal disease, end-stage liver failure and intercurrent infection.

Helicobacter pylori: prevalence, clinical and endoscopic findings in children who underwnet upper endoscopy for abdominal ailments.

A total of 97 children aged 1 month to 16 years (mean 6.6 years) had upper endoscopies performed in Paediatric Institute, Kuala Lumpur Hospital between January 1997 and December 1999 for various gastrointestinal symptoms. Of these 70 children were tested for Helicobacter pylori. The four most common indications for upper endoscopy were recurrent abdominal pain, upper gastrointestinal bleeding, epigastric pain and vomiting. The overall prevalence of this infection in this heterogenous group of symptomatic children was 10% (7/70). This study shows that H.pylori positivity in a routine endoscopy population is low and does not appear to be associated with specific symptoms.

Disseminated histoplasmosis in a non-immunocompromised child.

We describe a 2 year-old non-immunocompromised girl with disseminated histoplasmosis who presented with a 2-month history of fever and bloody diarrhoea. On presentation, she was severely wasted and anaemic. There were gross hepatosplenomegaly and multiple lymphadenopathy. A septic screen was negative. A subsequent stool culture isolated Salmonella enteriditis. Serial Widal-Weil Felix (WWF) titres showed serological response after 2 weeks of Ceftriaxone. However, she continued to have spiking fever, bloody diarrhoea and weight loss. She developed pancytopaenia and disseminated intravascular coagulation. A bone marrow aspirate and trephine, and lymph node biopsy showed the presence of Histoplasma capsulatum, confirmed by Gomori-Methenamine Silver staining. She responded to intravenous amphotericin B followed by fluconazole (intravenous then oral) for 6 months after discharge. Human Immunodeficiency Virus screening tests were negative. Complement and immunoglobulin levels were normal. T and B enumeration tests showed gross leucopaenia with very low T cell function with defective phagocytic function. A repeat T and B cell enumeration test and phagocytic function tests done 3 months later were normal.

Significance of autoimmune haemolytic anaemia and immune thrombocytopenia (Evans' syndrome) in systemic lupus erythematosus.

Patients with systemic lupus erythematosus (SLE) have an extremely variable prognosis and mortality. The purpose of this report is to highlight the importance of looking for lupus parameters in patients with autoimmune haemolytic anaemia (AIHA) and/or immune thrombocytopenia (ITP) as this represents a subgroup of systemic lupus erythematosus (SLE) patients with a fairly good prognosis. We report a case of an 8-year-old Malay boy who was admitted to hospital with fever and gum bleeding. Physical examination revealed a malar rash, oral ulcers, petechial haemorrhages and bruises over the limbs, generalised lymphadenopathy and hepatosplenomegaly. Laboratory investigations confirmed the diagnosis of SLE. The patient's serum showing the presence of antinuclear factor, antiphospholipid antibodies and a biological false-positive test for syphilis. Immunological and haematological parameters were in keeping with combined AIHA and ITP (Evans' syndrome). No organ involvement was present and the patient responded well to corticosteroid therapy. This case demonstrates the importance of making an early diagnosis of SLE with haematological complications, in order to ensure full benefit of therapy and emphasises the good prognosis expected in this subgroup of SLE patients.