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| 2. |
- Olsen, Henrik, et al.
(författare)
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Subclinical hypercortisolism and CT appearance in adrenal incidentalomas: a multicenter study from Southern Sweden
- 2012
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Ingår i: Endocrine. - : Springer Science and Business Media LLC. - 1355-008X .- 1559-0100. ; 42:1, s. 164-173
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Tidskriftsartikel (refereegranskat)abstract
- Evaluation of subclinical hypercortisolism (SH) in patients with adrenal incidentaloma (AI) including its correlation to size, attenuation at unenhanced computed tomography (CT) and unilateral or bilateral adrenal disease. Nine hospitals in Southern Sweden investigated during 2005-2007 consecutively patients with AI with hormonal and CT examinations according a regional protocol. Two hundred and twenty-eight patients with AI with median size 2.0 cm were included. One mg overnight dexamethasone suppression test (DST) was performed in 223 patients and basal P-ACTH measured in 146 patients. SH was defined as cortisol >= 50 nmol/l at DST in combination with basal ACTH <2 pmol/l. In patients with unilateral AI 42% (76/180) had inadequate suppression at DST and 23% (27/115) had SH. The probability for SH and inadequate suppression at DST correlated positively to size and inversely to attenuation at CT. Bilateral AI were found in 43 patients and of these 70% (30/43) had inadequate suppression at DST and 42% (13/31) SH. The patients with SH or inadequate suppression at DST had increased frequency of hypertension which increased further in patients with post-DST cortisol >= 140 nmol/l. The applied criterion for SH is useful for initial evaluation of patients with AI. SH is common in patients with AI, particular in bilateral disease. In patients with unilateral AI the probability for SH correlated positively to size and inversely to attenuation at CT. Furthermore, SH and the post-DST cortisol concentration was associated with hypertension.
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| 3. |
- Steffenburg-Nordenström, Joachim, 1962-
(författare)
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Process chain simulation of forming, welding and heat treatment of Alloy 718
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Manufacturing of aero engine components requires attention to residual stress and final shape of the product in order to meet high quality product standards.This sets very high demands on involved manufacturing steps to meet design requirements. Simulation of manufacturing processes can therefore be animportant tool to contribute to quality assurance.The focus in this work is on simulation of a manufacturing process chain comprising of sheet metal forming, welding and a stress relief heat treatment.Simulation of sheet metal forming can be used to design a forming tool design that accounts for the material behaviour, e.g. spring back, and avoid problems such as wrinkling, thinning and cracking. Moreover, the simulation can also show how the material is stretched and work hardened. The residual stresses after forming may be of local character or global depending on the shape that is formed. However, the heat affected zone due to welding is located near the weld.The weld also causes large residual stresses with the major component along the weld. It is found that the magnitude of the residual stresses after welding is affected by remaining stresses from the previous sheet metal forming. The final stress relieve treatment will relax these residual stresses caused by e.g. forming and welding. However, this causes additional deformations.The main focus of this study is on how a manufacturing process step affects the subsequent step when manufacturing a component of the nickel-based super alloy 718. The chosen route and geometry is a simplified leading edge of an exhaust case guide vane. The simulations were validated versus experiments. The computed deformations were compared with measurements after each manufacturing step. The overall agreement between experiments and measurement was good. However, not sufficiently accurate considering the required tolerance of the component. It was found from simulations that the residual stresses after each process affects the subsequent step. After a complete manufacturing process chain which ends with a stress relief heat treatment the residual stresses were not negligible. VIII Special experiments were performed for studying the stress relief in order to understand how the stresses evolve through the heat treatment cycle during relaxation. It was found that the stresses were reduced already during the beginning of the heating up sequence due to decreasing Young´s modulus and yield stress with increasing temperature. Relaxation due to creep starts when a certain temperature was reached which gave a permanent stress relief.
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| 4. |
- Albers, Max B., et al.
(författare)
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Complications of surgery for gastro-entero-pancreatic neuroendocrine neoplasias
- 2020
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Ingår i: Langenbeck's Archives of Surgery. - : Springer Science and Business Media LLC. - 1435-2443 .- 1435-2451. ; 405:2, s. 137-143
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Surgery is recommended for most patients with gastro-entero-pancreatic neuroendocrine neoplasias (GEP-NENs). Rates of complications and perioperative mortality have been reported in few mostly retrospective single-center series, but there has been no detailed analysis on risk factors for perioperative complications and mortality to date. Methods: Data of patients with GEP-NENs operated between January 2015 and September 2018 were retrieved from EUROCRINE©, a European online endocrine surgical quality registry, and analyzed regarding rate and risk factors of surgical complications. Risk factors were assessed by logistic regression. Results: Some 376 patients (211 female, 167 male; age median 63, range 15–89 years) were included. Most NENs were located in the small intestine (SI) (n = 132) or pancreas (n = 111), the rest in the stomach (n = 34), duodenum (n = 30), appendix (n = 30), colon, and rectum (n = 22), or with unknown primary (n = 15). Of the tumors, 320 (85.1%) were well or moderately differentiated, and 147 (39.1%) of the patients had distant metastases at the time of operation. Severe complications (Dindo-Clavien ≥ 3) occurred in 56 (14.9%) patients, and 4 (1.1%) patients died perioperatively. Severe complications were more frequent in surgery for duodenopancreatic NENs (n = 31; 22.0%) compared with SI-NENs (n = 15; 11.4%) (p = 0.014), in patients with lymph node metastases operated with curative aim of surgery (n = 24; 21.4%) versus non-metastasized tumors or palliative surgery (n = 32; 12.1%) (p = 0.020), and in functioning tumors (n = 20; 23.0%) versus non-functioning tumors (n = 30; 13.5%) (p = 0.042). Complication rates were not significantly associated with tumor stage or grade. Conclusions: Severe complications are frequent in GEP-NEN surgery. Besides duodenopancreatic tumor location, curative resection of nodal metastases and functioning tumors are risk factors for complications.
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| 5. |
- Albers, Max B., et al.
(författare)
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Sentinel Lymph Node Biopsy in Thyroid Cancer
- 2020
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Ingår i: World Journal of Surgery. - : Springer Science and Business Media LLC. - 0364-2313 .- 1432-2323. ; 44, s. 142-147
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prophylactic central neck dissection in patients with papillary thyroid carcinoma is controversial. Sentinel node biopsy might be an adjunct to optimize surgical treatment for these patients. Earlier studies reported inconsistent detection rates and diagnostic value of this technique, and the role of sentinel lymph node biopsy in thyroid cancer needs to be established. Patients and methods: During a single-center prospective interventional study between 2010 and 2017, sentinel lymph node biopsy using 99mTc-nanocolloidal albumin tracer was performed on patients undergoing thyroid surgery for suspected thyroid cancer by fine needle aspiration cytology. All eligible patients without clinical lymph node involvement were invited to participate. Central neck dissection was performed on all patients after the detection of sentinel lymph nodes. Results: Ninety-six patients participated in the study. The detection rates of the sentinel node were 67% and 45% by scintigraphy and intraoperative gamma probe, respectively. The detection rate was not associated with Bethesda score, malignancy, or presence of lymph node metastases. Sensitivity, negative predictive value, and accuracy were 80%, 97%, and 98%, respectively, for the sentinel node to represent the status of lymph node metastasis in the central neck compartment. The false negative rate was 20%. Conclusion: Sentinel lymph node biopsy had a low detection rate and only moderate sensitivity in patients with suspected thyroid carcinoma and is not a useful adjunct to surgery in the context of current treatment concepts.
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| 6. |
- Almquist, Martin, et al.
(författare)
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Changing biochemical presentation of primary hyperparathyroidism.
- 2010
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Ingår i: Langenbeck's Archives of Surgery. - : Springer Science and Business Media LLC. - 1435-2451 .- 1435-2443. ; 395, s. 925-928
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Patients with primary hyperparathyroidism, pHPT, present with milder symptoms than previously. Some, but not all studies, suggest that this change in clinical pattern also implies lower preoperative parathyroid hormone (PTH) and/or calcium levels and smaller adenomas. This is important since reports indicate that smaller adenomas are more difficult to detect on preoperative imaging, possibly increasing the risk of surgical failure. METHODS: There were 640 patients with histologically confirmed single-gland pHPT identified in a prospectively collected database. Median values of preoperative calcium, PTH, as well as adenoma weight were compared in three different time periods: 1990-1995, 1996-2000, and 2000-2007. Correlation between the preoperative levels of calcium and PTH and adenoma weight was calculated. RESULTS: Preoperative ionized calcium decreased significantly over time (p < 0.001). There was a positive correlation between preoperative PTH and adenoma weight (r = 0.32, p < 0.001). The magnitude of this correlation decreased over time. In women, adenoma weight decreased significantly over time (p = 0.03). Median (25th-75th percentile) adenoma weight in women was 750 (400-1,380) mg, 650 (350-1,205) mg, and 520 (305-1,065) mg in the first, second, and third period, respectively. CONCLUSION: From 1990 to 2007, there was a significant trend to operate pHPT patients with lower preoperative serum ionized calcium levels. In women, the adenoma weight decreased. This trend could potentially lead to decreased sensitivity in preoperative localization procedures.
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| 7. |
- Almquist, Martin, et al.
(författare)
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Management of the exterior branch of the superior laryngeal nerve among thyroid surgeons - Results from a nationwide survey.
- 2015
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Ingår i: International Journal of Surgery. - : Ovid Technologies (Wolters Kluwer Health). - 1743-9159 .- 1743-9191. ; 20, s. 46-51
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Tidskriftsartikel (refereegranskat)abstract
- The external branch of the superior laryngeal nerve is important for the voice. However, it is unknown how thyroid surgeons manage this nerve during operations. We hypothesised that this management is related to the surgeon's age, gender, the surgeons' annual number of thyroid operations, i.e volume, and surgical specialisation.
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| 8. |
- Almquist, Martin, et al.
(författare)
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Prediction of Permanent Hypoparathyroidism after Total Thyroidectomy.
- 2014
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Ingår i: World Journal of Surgery. - : Springer Science and Business Media LLC. - 1432-2323 .- 0364-2313. ; 38:10, s. 2613-2620
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Tidskriftsartikel (refereegranskat)abstract
- Hypoparathyroidism is a common complication with thyroid surgery. The ability to predict a high risk of permanent hypoparathyroidism is important for individual prognosis and follow-up.
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| 9. |
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| 10. |
- Annebäck, Matilda
(författare)
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Hypoparathyroidism after thyroid surgery- rates, risks, prevention and consequences
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hypoparathyroidism is the most common complication after thyroid surgery and associated with short- and long-term consequences. The lack of a consensus on the definition of hypoparathyroidism has led to a broad range in the rates reported in the literature. The overall aim of this thesis was to study different aspects of hypoparathyroidism, in terms rates, risks and long-term impact. Paper I is a case control study, investigating prophylactic, preoperative treatment with active vitamin D and early hypocalcemia after total thyroidectomy. The study showed that patients with preoperative treatment had a lower risk of early hypocalcemia and a reduced length of stay in hospital, compared to patients without treatment. No adverse outcomes were found. Paper II is a population-based retrospective cohort study on the rate and risks for permanent hypoparathyroidism after total thyroidectomy for benign thyroid disease. Data was retrieved from The Swedish National Patient Register, The Swedish Quality Register for Thyroid, Parathyroid and Adrenal Surgery and The Swedish Prescribed Drug Registry. Permanent hypoparathyroidism was defined as dispensation of calcium and/or active vitamin D >12 months after surgery. Among 7852 patients, 12.5% developed permanent hypoparathyroidism. Surgery at low volume centers, parathyroid autotransplantation, female gender and high age were independent risk factors. In Paper III the aim was to validate the high rate of permanent hypoparathyroidism found in Paper II. A regional cohort was extrapolated from the national cohort. A retrospective chart review, of 1636 patients, was performed. Using a strict definition, 6.2 % were found to have definitive permanent hypoparathyroidism. Additionally, 2.5 % were found to have possible permanent hypoparathyroidism. Of these, at least 1.7 % might have been overtreated due to lacking attempts to unwind the treatment. The study also proposed that the rate of low early PTH in a cohort might be useful to predict the rate of permanent hypoparathyroidism. Paper IV investigated health related quality of life (HRQoL) in patients with and without permanent hypoparathyroidism using the same cohort as in Paper III and SF-36 v.2. No impact of definitive hypoparathyroidism on HRQoL could be found. In conclusion, the use of preoperative active vitamin D may be useful as a tool to lower the risk of early hypocalcemia. The risk of permanent hypoparathyroidism after total thyroidectomy is high and there is a need for improved follow up. Permanent hypoparathyroidism may not have a negative effect on HRQoL in most patients.
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