Biomedical subjects
Publications and source records attributed to M R Pelizzo.
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Thyroid cancer is a relatively common clinical problem. The American Cancer Society has estimated 1,050,000 newly diagnosed cancers in 1999 in the United States, of which 16,000 are expected to be of thyroid origin. Although most thyroid cancers have an excellent prognosis as compared with other malignant tumors, it is estimated that approximately 1,225 deaths will be attributed to the disease [1].
We report the preliminary results obtained with the intraoperative MIBI-guided gamma probe in a group of 9 patients with primary hyperparathyroidism (pHPT). These patients were selected for limited invasive parathyroid surgery on the basis of a preoperative imaging protocol consisting of a pertechnetate & perchlorate/MIBI scan combined with neck ultrasonography (US). In the operating room 50-70 MBq MIBI was injected 30 to 45 min before parathyroidectomy. The radioactivity was measured intraoperatively at three sites: parathyroid (P), thyroid (T), and background (B). The P/B, P/T, and T/B ratios were calculated. The T/B ratio was relatively constant (range, 1.5-1.8; mean, 1.6), while a wide variability was observed both for P/T ratio (range, 1.2-2.3; mean, 1.7) and P/B ratio (range, 2.1-4.0; mean, 2.9). At surgery single enlarged parathyroid glands were easily identified by means of intraoperative MIBI-guided gamma probe. Moreover, the gamma probe allowed us to perform a limited 2-2.5 cm neck incision in eight patients affected by parathyroid adenoma. In the remaining patient a parathyroid carcinoma was diagnosed and a bilateral neck exploration was performed. The intraoperative MIBI gamma probe seems to be a useful aid when limited invasive parathyroid surgery is performed.
UNLABELLED: AIMS AND STUDY DESIGN: We investigated the role of an intraoperative gamma probe (IGP) technique in 128 patients with primary hyperparathyroidism (HPT). The patients were evaluated before surgery by 99mTc04/MIBI scintigraphy and neck ultrasound and then operated on by the same surgical team. The IGP technique consisted of the injection of a low dose (37 MBq) of 99mTc-MIBI in the operating room shortly before the start of surgery. Quick parathyroid hormone (QPTH) was routinely measured during the operation. RESULTS: In 94/97 patients (96.9%) with a preoperative diagnosis of solitary parathyroid adenoma (PA) minimally invasive radioguided surgery (MIRS) was successfully performed; in the other 3/97 patients (3.1%) conversion to bilateral neck exploration (BNE) was required because of the intraoperative diagnosis of parathyroid carcinoma in two cases and multiglandular disease (MGD) in one. MIRS was successfully performed also in 23 patients who had undergone previous thyroid or parathyroid surgery. In 31 patients with a preoperative diagnosis of MGD (n = 5) or concomitant nodular goiter (n = 26) the IGP technique was used during a bilateral neck exploration. Among these patients IGP was useful in localizing an ectopic parathyroid gland in the thymus in one case of MGD and a PA located deep in the neck (n = 2) or ectopic at the carotid bifurcation (n = 1) in three cases with nodular goiter. However, in several other patients with nodular goiter it was difficult for the probe to distinguish intraoperatively between thyroid nodules and PA located close to the thyroid gland. CONCLUSIONS: It can be concluded that a) in primary HPT patients with a high likelihood (according to scintigraphic and ultrasound findings) of being affected by a single PA and with a normal thyroid gland, the IGP technique appears useful in MIRS; b) a 99mTc-MIBI dose as low as 37 MBq appears to be adequate to perform MIRS; c) the measurement of QPTH is strongly recommended in HPT patients selected for MIRS to confirm the radicality of parathyroidectomy; d) MIRS can be useful also in HPT patients who underwent previous parathyroid or thyroid surgery to limit the surgical trauma of reoperation and minimize complications; e) with the exception of PAs located at ectopic sites or deep in the neck, the IGP technique does not seem to be recommendable in HPT patients with concomitant nodular goiter.
AIMS AND BACKGROUND: The aim of the study was to analyze the frequency of thyroid carcinoma in a consecutive series of 539 thyroidectomies for multinodular goiter (MNG) and to assess the influence of sex and age as cancer risk factors. METHODS: In a 2-year period, 539 patients underwent subtotal or total thyroidectomy for MNG at the institute of General Surgery, University of Padova, Padova, Italy: 455 were females and 84 males (F/M = 5.5/1); mean age was 46 years (min. 17, max 78). Only 17 patients (3.1%) (16 females and 1 male) were aged 21 years or less. RESULTS: A malignancy was found in 41 patients: 38 females and 3 males; 39 older and 2 younger than 21 years. The frequency of cancer in MNG was 7.6%: 8.3% in females and 3.6% in males; 7.5% in patients older than 21 and 11.7% under 21 years. CONCLUSIONS: The combination of MNG and carcinoma should always be carefully considered but not overemphasized, and the policy of surgically treating all patients with MNG is not justified. Sex and age cannot be considered as factors of a higher risk of cancer.
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AIMS AND BACKGROUND: The aim of this study was to define the clinical impact of MIBI scan combined with neck ultrasonography on the detection of metastates in differentiated thyroid carcinoma (DTC) patients with elevated serum Tg levels but negative 131I scan (non-functioning DTC). METHODS AND STUDY DESIGN: Eighty-two patients with non-functioning DTC, 19 patients with 131I-positive metastases (functioning DTC), and 24 DTC patients who were disease free after therapy (no cancer patients) were enrolled. 131I scan was performed after administration of low diagnostic and high therapeutic tracer doses. Early and delayed images were obtained after MIBI injection. Neck-chest CT scan and/or MRI were also performed in patients with non-functioning DTC. RESULTS: In the group of non-functioning DTC patients, metastatic foci were detected in 71/82 cases: in the cervical lymph nodes in 51 cases (sensitivity 94.1% with MIBI, 90.2% with US, 35.3% with CT/MRI), mediastinal lymph nodes in 31 cases (sensitivity 100% with MIBI, 58% with CT/MRI), lungs in 8 cases (sensitivity 100% with both MIBI and CT/MRI), and bone in 2 cases (sensitivity 50% with MIBI, 100% with MDP bone scan). Among the 19 patients with functioning DTC a close relationship between MIBI and 131I findings was observed. As regards the 24 tumor-free patients, MIBI was correctly negative in all cases, while US visualized enlarged cervical lymph nodes that were suspected to be neoplastic but proved to be inflammatory lesions at cytology in three patients. CONCLUSIONS: On the basis of these data, MIBI scan combined with neck US could be proposed as a first-line diagnostic imaging modality in the follow-up of DTC patients with elevated serum Tg levels and negative 131I scan.
Frequency of complications in thyroid surgery is evaluated in a series of patients treated during a recent period lasting one year (1997). The records of 455 patients consecutively operated on were analyzed: 396 patients were affected by benign disorders and 59 by thyroid carcinoma. Total thyroidectomy was performed in 158 cases, near subtotal thyroidectomy in 94, thyroid totalization for recurrent disease in 21 and lobectomy in 182 ones. Post-operative haemorrhage, such to require surgical re-exploration of the thyroid bed, occurred in 2 patients (0.4%), both after total thyroidectomy for hyperfunctioning goiter. Recurrent laryngeal lesion has been observed in 2 patients (0.4% of all patients), both after total thyroidectomy for cervico-mediastinal goiter. Transient hypoparathyroidism occurred in 48 patients (10.5%), while definitive one in 9 (1.9%), of which 5 after total thyroidectomy, 2 after subtotal thyroidectomy and 2 after reoperation. Haemorrhage nearly always occurs in the first postoperative hours and gravity is conditioned by tracheal compression exercised by the haematoma. An aspirative drainage located in thyroid bed and a not hermetic closure of the middle line help a precocious diagnosis and sometimes avoid a surgical re-exploration. Some technical surgical devices permit to reduce the risk of inferior laryngeal nerve palsy. Hypoparathyroidism, often transient, is a complication of bilateral thyroid surgery, but unavoidable when more extensive thyroid surgery is required.
BACKGROUND: The purpose of our study is to verify if PTH assay on the first postoperative day is a reliable early predictor of the onset of hypocalcemia. METHODS: Between October 1999 and May 2000, a prospective trial involved 162 patients who underwent total or near total thyroidectomy at our institute. On the basis of PTH assay on first day we divided the patients in three groups: group A 28 patients with PTH < 10 pg/ml; group B 34 patients with PTH between 10 and 16 pg/ml; group C 100 patients with PTH > 16 pg/ml. RESULTS: In group A: 22 of 28 patients (78.5%) developed postoperative hypocalcemia and 20 (71.4%) needed replacement therapy; in group B: 14 of 34 (41.1%) had postoperative hypocalcemia and 10 (29.4%) received treatment; in group C: 23 of 100 (23%) became hypocalcemic after surgery but only 5 (5%) require calcium-vitamin therapy. A statistically significant correlation (p = 0.0017) was identified between post-operative PTH levels and lowest blood calcium values detected after surgery. The correlation between the drop in blood calcium levels after surgery and postoperative PTH (delta Ca) was statistically even more significant (p = 0.0002); the lower the postoperative PTH, the higher the absolute value of the delta Ca. CONCLUSION: The authors suggest a clinical approach and pharmacological treatment protocol based on the outcome of PTH assay on the first post-operative day; a solution that is only apparently more costly because it in fact aims to ensure a more timely recourse to blood calcium monitoring or replacement therapy and also an earlier discharge of the patient.
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Multinodular goitre is a very common, and commonly benign, thyroid disorder; however variable and sometimes surprisingly high occurrence of malignancy has been reported in surgical series. In this connection we retrospectively analyzed a large consecutive series of 539 thyroidectomies performed for M.N.G. over a short period of time of 3 years: there were 455 female and 84 male patients, of whom 522 over and 17 under 21 years of age. It was found an overall incidence of carcinoma of 7.5% (90.2% of papillary type), with prevalence in female (8.3%) vs male sex (3.6%) and in patients under (11.7%) vs over (7.5%) the age of 21 years; differences for sex and age were not significant. We remark that present revision left out of consideration other known factors predisposing to cancer, and included occult papillary carcinomas that are a frequent autoptic finding and do not affect life expectancy. Surgical selection, in addition to these circumstances, concurred to distort, making higher than true, the incidence of cancer in M.N.G. We conclude that M.N.G. cannot be considered as a condition predisposing to cancer but it may harbour a cancer; since that selective surgical approach is recommenced. Selection criteria for surgery and treatment are mentioned.
The forgotten goiter is most often the consequence of the incomplete removal of a "plunging" goiter, but it can sometimes be attributed to a concomitant, unrecognised mediastinal goiter which is not connected to the thyroid. Differential diagnosis must be made with other mediastinal masses and with plunging relapses of a previously operated struma. Radiological analysis of persisting mediastinal involvement before and immediately after surgery is the only decisive means of diagnosis, but this is not always available in practice. In this paper the authors report a case of considerable size observed in a series of 346 mediastinal goiters operated between 1967 and 1994. They examine the pathogenetic aspects and the nosological, diagnostic and therapeutic problems related to forgotten goiter, and lastly they list the recommendations that several surgeons have made in an attempt to reduce the incidence. In conclusion, the systematic use of CAT or NMR in the diagnosis of mediastinal opacity may help to reduce the risk of forgetting glandular residue in the mediastinum.