Cost-effectiveness of preoperative localization studies in primary hyperparathyroid disease

OBJECTIVE: To evaluate the effect of preoperative localization studies on the surgical management of patients with primary hyperparathyroid disease (PHPT). SUMMARY BACKGROUND DATA: Reported cure rates of initial surgical exploration for PHPT are close to 95%. Preoperative localization studies are frequently obtained to improve surgical success and decrease operative time. METHODS: Initial cervical exploration was performed in 113 patients with PHPT from 1981 to 1993. Twenty-four patients (21%) had surgery without preoperative localization studies. The remaining 89 patients (79%) had 132 noninvasive preoperative localization studies. Success of the localization studies in tumor localization, pathologic findings, postoperative serum calcium levels, and operative times were compared. Patient costs of the studies were calculated. RESULTS: Disease was identified during operation in 23 of 24 patients (96%) having cervical exploration without preoperative localization studies, and they had normal calcium levels after surgery. Eighty-seven of 89 patients (98%) having preoperative localization studies were surgically cured. The highest sensitivity rate (60%) and highest positive predictive value (79%) of the localization studies were found with thallium-technetium scintiscanning. Average cost of the localization studies was $901 per patient. Combination studies were obtained in 32 patients at an average cost of $1,314 per patient without improving sensitivity. Mean operating time did not differ for localized and nonlocalized patients. CONCLUSIONS: Preoperative localization studies did not improve parathyroid localization or cure rate and did not substantially shorten operating time in initial cervical exploration for PHPT. The economic burden of routine preoperative localization studies in these patients is not justified.     

Value of ultrasonography, CT and MR imaging in the diagnosis of primary hyperparathyroidism

PURPOSE: To evaluate the significance of preoperative localization of abnormal parathyroid glands to the surgical outcome in patients with primary hyperparathyroidism. MATERIAL AND METHODS: Thirty-nine patients with primary hyperparathyroidism were studied preoperatively with US (39 patients), CT (30 patients) and MR imaging (18 patients). The overall diagnostic accuracy for US was 87%, CT 66% and MR 94%. In patients with a single parathyroid adenoma US was the most cost-effective localization technique with a detection rate of 96%. CT had a lower detection rate (78%) but was of particular value for fairly large ectopic adenomas in the root of the neck. MR imaging was a good confirmatory test (93%). In patients with multiple gland disease (primary hyperplasia and multiple adenomas), no single localization study alone was sufficient. Combination of all 3 studies, however, alerted the physician to the presence of disease in more than one gland in 87% of these patients. CONCLUSION: US, CT and MR imaging followed by surgery performed by an experienced surgeon provided good clinical results in 39 patients with primary hyperparathyroidism. Preoperative localization was especially useful in patients with primary parathyroid hyperplasia or multiple adenomas and in patients with ectopic parathyroid adenomas in the root of the neck. We recommend identification of all abnormal parathyroid glands prior to surgery.     

Results of a standardized treatment concept in primary hyperparathyroidism

BACKGROUND AND OBJECTIVE: Primary hyperparathyroidism (PHPT) is being diagnosed ever more frequently. After diabetes mellitus, ovarian dysfunction and metabolic disorders it is now among the most frequent metabolic disease. Its surgical treatment has become standardized with increasing experience. A prospective study was undertaken to clarify to what extent our own standardized diagnostic and therapeutic measures conform to current standards in literature. PATIENTS AND METHODS: During 10 years (1. 1. 1987-31. 12. 1996) 478 patients with PHPT were treated surgically (solitary adenoma: 317 (76.5%), multiple lobe hyperplasias 66 (15.9%), double adenoma 28 (6.8%), and carcinoma 4 (0.8%). PHPT was part of the MEN (multiple endocrine neoplasia) syndrome in 20 patients. Typical symptoms of PHPT had been present in 400 patients (83.7%), while 78 (16.3%) had no manifest symptoms. Ultrasound examination of the soft tissues was the only preoperative test of localization. More extensive preoperative diagnosis was practised only before reoperations. All patients had bilateral exploration of the neck to try and demonstrate all four epithelial bodies. RESULTS: A primary operation normalized the calcium level in 405 of 414 patients (97.8%). In 64 previously unsuccessfully operated patients who were reoperated for persisting HPT the elevated calcium levels could be normalized in 90.6%. Hypercalcaemia was finally abolished in all 478 patients. Average follow-up duration for 319 patients was more than 4.8 (0.5-8.5) years. The perioperative mortality rate was 0.8 (4 of 478), with 41 deaths during the later follow-up period. Permanent recurrent laryngeal nerve palsy occurred in 6 patients (1.8%). Long-term calcium substitution was necessary postoperatively in four patients (1.2%). CONCLUSION: Our findings support a liberal policy towards indication for bilateral surgical exploration of the neck in PHPT.     

Primary hyperparathyroidism. Optimization of surgical results with systematic preoperative 99mTc-Sestamibi scintigraphy

OBJECTIVE: The importance of preoperative 99mTc Sestamibi (MIBI) scintigraphy in case of reoperation for persistent hyperparathyroidism is well recognized, but it use as a systematic exploration technique remains a question of debate. We conducted this study to determine whether preoperative MIBI scans performed in all cases before surgery have any real impact. METHOD: Two successive series of 65 operated patients were included in the study. In the first group, the MIBI scan was not performed prior to surgery while in the second group the MIBI scan was part of the systematic work-up. RESULTS: The sensitivity and positive predictive value of MIBI were 92% and 96% respectively. Sensitivity for unique adenomas was 95% and 80% for multiple forms. In the first group without systematic scans, there were two unproductive procedures. In the second group, all procedures were productive and no reoperations were required. Two mediastinal adenomas were removed at the first cervicotomy in this group. The rate of complications was similar for both groups. Mean operation time was 2 hours in the first group and 1 hour 30 minutes for the second. CONCLUSION: Our series shows that there are three main advantages of using MIBI scintigraphy systematically prior to surgery for hyperparathyroidism: the procedure is easier in patients with cervical adenomas, particularly in case of ectopic localizations; the mean duration of the operation is shortened by 30 minutes; mediastinal ectopic localizations can be removed by sternotomy at the first operation. These advantages appear to be great enough to propose systematic use of MIBI scan prior to surgery. When MIBI scan shows a single gland, the risk of missing a multiple localization is less than 2% in our experience. It appears possible to operate under local anesthesia via a single-sided approach in elderly patients or high-risk patients.     

Persistent and recurrent sporadic primary hyperparathyroidism: histopathology, complications, and results of reoperation

BACKGROUND: Our purpose was to analyze the causes of persistent and recurrent sporadic primary hyperparathyroidism (PD and RD). METHODS: The histopathology, complications, and results of reoperation were studied. Five hundred sixty-eight patients with primary hyperparathyroidism were operated on initially by one surgeon and underwent follow-up examination for 3.7 +/- 3.8 years. During the operation, all parathyroids were sought and confirmed by biopsy. Enlarged glands were resected, and subtotal parathyroidectomy was done for multiglandular disease (hyperplasia). RESULTS: The cure rate after the initial surgical procedure was 96.4%, PD = 2.8% (16 of 568). At reoperation (10 of 16), nine of 10 were cured (90%) (two adenomas, six hyperplasias, one lung carcinoma). RD was documented (at years 4, 4, 10, 15, 16) in five (0.9%) patients, one with parathyroid carcinoma and four with hyperplasia. Thirty-five patients with PD and two patients with RD were referred for reoperation: 17 with adenomas (eight mediastinal) and 18 with hyperplasias (one mediastinal gland). Preoperative calcium level was higher for PD (12.57 mg/dl) and RD (13.89 mg/dl) versus all cases (12.19 mg/dl) (p < 0.03 and p < 0.0005, respectively). After reoperation, normocalcemia was achieved in 47 (92.%) of 51 patients with PD or RD. Transient hypocalcemia occurred in 22% of patients (permanent, 2.0%) and transient hoarseness in 2.0% of patients (no permanent nerve damage). Permanent hypocalcemia and nerve damage after 568 initial operations were 0% and 0%, respectively. Two perioperative deaths occurred. CONCLUSIONS: We conclude that inadequate neck exploration or resection of hyperplastic tissue accounts for most cases of PD and RD. Optimal results necessitate intraoperative identification of all parathyroids whenever possible, with minimal morbidity.     

Effect of surgeon expertise on the outcome in primary hyperparathyroidism

BACKGROUND: Success in surgery for primary hyperparathyroidism (PHPT) is thought to be closely linked to surgical expertise. We investigated the effect of the surgeon's experience on the postoperative outcome in patients with PHPT. DESIGN: Cohort study with retrospective analysis. SETTING: University tertiary care center. PATIENTS: Two hundred thirty consecutive patients with PHPT. We excluded patients with prior cervical surgery, parathyroid carcinoma, multiple endocrine neoplasia types 1 and 2, and renal hyperparathyroidism. INTERVENTIONS: All 230 patients underwent bilateral neck exploration for PHPT. MAIN OUTCOME MEASURES: We registered complication rates, fulfillment of predefined operative concepts, and operative time in 230 cervical revisions for PHPT and compared the results of experienced surgeons (40 or more cervical revisions for PHPT performed before 1988) with those of surgeons still in training. RESULTS: Two surgeons classified as experienced operated on 75 patients. Under supervision of these surgeons, most operative procedures (n=155) were performed by 12 different surgeons classified as less experienced. Complications were observed in 31 patients (13.5%) with no statistical difference between the specialists and the less-experienced surgeons (P=.85). The ability to demonstrate 4 or more parathyroid glands was significantly increased for the specialists (74.7% vs 51.6%; P<.001), who also terminated the operation earlier (average, 15 minutes; P<.001). CONCLUSION: In an analysis of 230 operations for PHPT in patients without prior neck surgery, no effect of the surgeon's experience on postoperative outcome was demonstrated. Under the supervision of experienced endocrine surgeons, less-experienced surgeons perform cervical revisions for PHPT with comparable results, although with longer operating time.     

Cost utility of routine imaging with Tc-99m-sestamibi in primary hyperparathyroidism before initial surgery

Tc-99m-sestamibi has been shown to localize parathyroid adenomas effectively, but controversy continues as to the use of this scan before initial surgery for primary hyperparathyroidism. We analyzed the cost utility of obtaining this study before initial surgery for primary hyperparathyroidism. Twenty-two consecutive patients with primary hyperparathyroidism underwent dual-phase Tc-99m-sestamibi scan before initial bilateral neck exploration. Surgical findings were correlated with the results of sestamibi scan. There were 15 women and 7 men, with a mean age of 50.5 years (range, 22-76). Preoperative mean total calcium was 11.74 mg/dL (range, 10-15), ionized calcium was 6.19 mg/dL (range, 5.2-7.7), and intact parathyroid hormone was 153.5 pg/mL (range, 83.1-551). Postoperative mean ionized calcium was 4.56 mg/dL (range, 4.1-5.57). Twenty sestamibi scans had a positive localization, and 2 scans had no localization. At surgery, 18 solitary adenomas, 3 diffuse hyperplasias, and 1 patient with four normal parathyroid glands were found. Sixteen sestamibi scans were true positive (solitary adenoma), 4 scans were false positive (2 diffuse hyperplasia, 1 wrong side, and 1 lymph node), 1 negative scan was true negative (diffuse hyperplasia), and 1 negative scan was false negative (adenoma). One patient (four normal glands) at the second operation had a supernumerary fifth gland adenoma excised from the mediastinum. Preoperative Tc-99m-sestamibi scan did not offer any advantage when a complete bilateral neck exploration is performed. Sixteen of (84%) adenomas were correctly localized, but 18 of 19 adenomas were in the neck and were easily found. The 1 ectopic adenoma was not found by scanning or with initial surgery. The 4 of 22 (18%) false-positive localizations and the 2 of 22 (9%) negative scans contributed nothing to the surgery. Of the 22 localizing sestamibi scans, surgery was not altered to affect the outcome. At a cost of $550 per sestamibi scan and with the error inherent in the scan, it is not cost effective to obtain Tc-99m-sestamibi scan before initial surgery for primary hyperparathyroidism.     

Initial cervical exploration for parathyroidectomy is not benefited by preoperative localization studies

Published data is controversial as to the ability of preoperative localization studies (PLS) to enhance the outcome of initial cervical exploration in patients with primary hyperparathyroidism (PHPT). One surgeon's experience was reviewed to compare surgical success, operative time, and morbidity of initial cervical exploration for PHPT in patients who had undergone PLS versus those who had not. From August 1991 to September 1997, 95 patients who had not undergone prior central cervical exploration presented for surgical management of PHPT. Sixty-seven patients underwent initial cervical exploration without any PLS having been performed (Group A). Twenty-eight patients underwent PLS, either alone or in combination, before surgical intervention (Group B). Analysis of intergroup variability was conducted upon the data available using a two-tailed t test for independent samples. In addition, the sensitivities and positive predictive values of the PLS were calculated using study reports and operative and histologic findings. There was no statistically significant difference in surgical success between those patients who had PLS and those that did not undergo PLS. Sixty-four of 67 patients (95.5%) not having PLS were cured with initial surgery, while 27 of 28 patients (96.4%) who had PLS were surgically cured. Mean postoperative calcium and intact parathormone levels were similar between the two groups, and the mean operative time did not differ. Permanent hypocalcemia occurred in one patient, and five patients had transient hoarseness. Thirty-six total PLS were obtained at an average cost of $752.68/patient, and seven patients underwent multiple tests. Overall, sestamibi scan had the highest positive predictive value (81%). For adenomatous disease alone, sestamibi scan was the most sensitive (83%). Our study shows that for matched groups limited to age, sex, and clinical diagnosis, the use of PLS did not shorten operative time, decrease complication frequency, nor alter the success of the operation as measured by postoperative calcium and parathormone levels. Therefore, routine use of preoperative localization studies before initial cervical exploration for PHPT cannot be recommended.     

Management of hyperparathyroidism in an endemic goiter area

In an endemic goiter area patients with hyperparathyroidism (HPTH) frequently also have thyroid abnormalities. In a retrospective study of 95 patients with HPTH we assessed the diagnostic accuracy of imaging techniques (ultrasonography or radionuclide scanning) for preoperative localization of parathyroid adenomas. Altogether 86% of our patients had goiter, requiring thyroid resections in 37%. For 19 patients the parathyroid exploration was the second or third cervical operation, most of them due to goiter. We found that the overall rate of transient and permanent recurrent nerve paralysis is considerably increased in patients with previous neck surgery (26% vs. 7%). The combination of ultrasonography and radionuclide scanning can lead surgeons to the site of parathyroid lesions responsible for HPTH in 85% of cases, although frequent nodular goiters can produce pitfalls for correct imaging in iodine-deficient countries. In endemic goiter areas preoperative localization studies can be recommended in patients with primary HPTH--for evaluation of thyroid pathology possibly leading to resection or its accuracy in localizing parathyroid adenomas. These studies also seem justified in patients with previously unsuccessful neck explorations for HPTH.     

Technetium 99m tetrofosmin parathyroid imaging. Results with double-phase study and SPECT in primary and secondary hyperparathyroidism

RATIONALE AND OBJECTIVES: The aim of our study was to evaluate the sensitivity, specificity, and positive predictive value (PPV) of technetium 99m (99mTc) tetrofosmin double-phase scintigraphy and single-photon emission computer tomography (SPECT) in preoperative localization of parathyroid adenoma in case of primary and secondary hyperparathyroidism (HPT). METHODS: Sixty-eight consecutive patients biochemically or sonographically suspected of parathyroid adenoma were included in our study. Apart from biochemical analysis of serum calcium, phosphate, and intact parathyroid hormone, double-phase scintigraphy was performed in each patient 5 and 45 minutes after injection of 370 MBq 99mTc tetrofosmin, followed by SPECT imaging. In consciousness of the scintigraphic results, ultrasound of the neck was performed as well to exclude false-positive results due to thyroid adenomas. RESULTS: Depending on the results of the biochemical analysis in combination with the results of the scintigraphic and ultrasound examination, the patients were classified retrospectively into three groups: group A with primary HPT (n = 35), group B with secondary HPT (n = 13), and group C without any biochemical suspicion of primary or secondary HPT (n = 20). In group A, double-phase study localized 25 of 36 (69.2%) parathyroid adenomas (one double adenoma) as against 34 of 36 (94.4%) with SPECT. Nine adenomas could be visualized only by SPECT. The reason for nonvisualization on planar scans was suspected to be an ectopic location in 2 cases (retrotracheal dislocation, retrovascular dislocation), a maximal diameter less than 15 mm (9-13 mm) in 6 cases, and oxyphilic-cell-poor cellularity in 1 case. Four false-positive retention (3 thyroid adenomas and 1 papillary thyroid carcinoma) were observed. SPECT showed a sensitivity of 94.4%, a specificity of 85%, and a PPV of 91.9% in biochemically suspected primary HPT. In group B, planar scintigraphy demonstrated 12 hyperplastic glands in 5 of 13 patients, and SPECT demonstrated 20 hyperplastic parathyroid glands in 8 out of 13 patients, which corresponds to a sensitivity of 38% and 61.5%, respectively. CONCLUSIONS: Technetium 99m tetrofosmin seems to be a promising alternative tracer with similar capabilities to 99mTc sestamibi in localization of parathyroid adenoma. SPECT showed clear advantages in terms of sensitivity over planar scintigraphy and should be used at least in cases with poor or no uptake in double-phase study. In endemic goiter areas, ultrasound of the neck should be performed to exclude false positive retention in thyroid adenomas. Technetium 99m tetrofosmin, like 99mTc sestamibi, is not ideal for localization of hyperplastic glands in secondary hyperparathyroidism because of low sensitivity.     

Stapedial reflex: a biological index found to be abnormal in clinical and subclinical hypothyroidism

INTRODUCTION: Parathyroidectomy via cervical exploration is an effective primary-modality treatment for hyperparathyroidism, with cure rates of greater than 95%. We retrospectively reviewed 866 consecutive parathyroidectomies performed by a single surgeon between 1960 and 1997. We attempted to describe the polymorphic variation in multiglandular disease, the anatomic locations of pathologic glands, and the operative strategy and techniques which we believed were important to minimizing morbidity and maximizing curative success. METHODS: The cases of 329 males and 537 females (age, 1-88 years) were reviewed. There were 766 operations performed: primary hyperparathyroidism (713), tertiary hyperparathyroidism (100), reoperations (53). The strategy for primary exploration includes a bilateral neck exploration, early recurrent laryngeal nerve skeletonization, and identification of at least four glands. RESULTS: Normocalcemia was achieved in 98.2% of cases after initial cervical exploration. Persistent hypercalcemia occurred in 7 patients (<1%). Nine patients (1%) suffered persistent postoperative hypocalcemia. Unilateral recurrent laryngeal nerve injury occurred in two patients (<1%). Other perioperative complications included: reoperation for hematoma, repaired carotid artery injury, unexplained dysphagia, pneumothorax, deep venous thrombosis, and aspiration pneumonia. There were two mortalities (<1%) attributable to severe, comorbid disease. Ectopic glands were found in 120 cases. The frequency of glands at these sites were as follows: mediastinal (4.9%), intrathymic (8.4%), intrathyroid (6.7%), and retroesophageal/retrotracheal (3.5%). Thyroid resections provided diagnosis of concomitant thyroid carcinoma in 8.0% of resected patients. The pathology of patients with primary hyperparathyroidism (PHPT) consisted of single adenomas (77.2%), hyperplasia (21.0%), normal glands (1%), double adenomas (<1%), and parathyroid carcinoma (<1%). The distribution of adenomas was as follows: left upper, 25.3%; left lower, 27.3%; right upper, 26.8%; right lower, 20.6%. Hyperplastic glands were found in ectopic positions as follows: intrathymic (7.5%), intrathyroid (11.3%), mediastinal (2.5%), and retroesophageal/retrotracheal (0%). The average volume difference between the largest and smallest hyperplastic gland of each case was 1.80 + 4.40 cm3. Reoperations were performed upon 53 referred patients and 7 patients after failed exploration. Normocalcemia was attained in 98.3% of cases. Glandular pathology was identified in the previous operative field in 52 patients (86.7%). Adenomas were identified in 56.0% (n = 23) and hyperplasia in 39.0% (n = 16). CONCLUSIONS: In our series, we were able to attain normocalcemia in 98.2% of cases after initial cervical exploration. We believe that identification of four glands, an exhaustive search of ectopic sites, bilateral exploration, and liberal use of biopsy and intraoperative frozen section were essential to curative success. The pathologist should identify parathyroid tissue in the specimen and differentiate the "abnormal" from "normal" gland. Morphologic criteria alone cannot be used because of polymorphic variation in hyperplasia in which pathologic glands may appear normal. Early identification of the recurrent laryngeal nerve allows for a safer neck exploration by alerting the surgeon to the location and course of the nerve. A bilateral approach does not contribute increased morbidity from recurrent laryngeal nerve injury.     

Secondary hyperparathyroidism is an expected consequence of parathyroidectomy for primary hyperparathyroidism: a prospective study

BACKGROUND: Parathyroidectomy for primary hyperparathyroidism (PHPT) can cause secondary hyperparathyroidism, with increased serum parathyroid hormone (PTH) and normal or low serum calcium concentrations. METHODS: A prospective study investigated 78 consecutive patients who underwent exploration for PHPT. Serum intact PTH and total calcium concentrations were measured the evening after operation and ionized Ca++ the following morning. These levels were reassayed 1 week later. RESULTS: Before operation, the mean PTH level was 138 +/- 15 pg/mL, total calcium concentration was 11.6 +/- 0.1 mg/dL, and ionized Ca++ concentration was 1.44 +/- 0.02 mmol/L. On the night of the operation, the PTH level was 11 +/- 2 pg/mL, and the total calcium concentration was 8.9 +/- 0.1 mg/dL. Fifty-five patients had hypoparathyroidism, with a PTH level less than 10 pg/mL. The day after the operation, the ionized Ca++ level was 1.14 +/- 0.01 mmol/L. One week later, PTH, ionized Ca++, and total serum calcium concentrations returned to normal levels. In 9 patients (12%), PTH levels were increased (98 +/- 16 pg/mL), although ionized Ca++ concentrations were normal (1.18 +/- 0.02 mmol/L), demonstrating secondary hyperparathyroidism. Risk factors for postoperative secondary hyperparathyroidism included older age, symptomatic hyperparathyroidism, higher preoperative PTH and alakaline phosphatase levels, and lower serum phosphorous levels. In 70% of these patients, PTH levels returned to normal in 3 to 12 months. CONCLUSIONS: Secondary hyperparathyroidism occurs in 12% of patients after surgical treatment of PHPT. It is transient, possibly compensating for relative hypocalcemia.     

Can pretreatment computed tomography predict local control in T3 squamous cell carcinoma of the glottic larynx treated with definitive radiotherapy?

PURPOSE: To determine if pretreatment computed tomography (CT) can predict local control in T3 squamous cell carcinoma of the glottic larynx treated with definitive radiotherapy (RT). METHODS AND MATERIALS: Forty-two patients with previously untreated T3 squamous cell carcinoma of the glottic larynx were treated for cure with RT alone; all had a minimum 2-year follow-up. Tumor volumes and extent were determined by consensus of two head and neck radiologists on pretreatment CT studies. A tumor score was calculated and assigned to each primary lesion depending on the extent of laryngeal spread. Sclerosis of any laryngeal cartilage was recorded. The specific CT parameters assessed were correlated with local control. RESULTS: Tumor volume was a significant predictor of local control. For tumors measuring < 3.5 cm3, local control was achieved in 22 of 26 patients (85%), whereas for tumors > or = 3.5 cm3, local control was achieved in 4 of 16 patients (25%) (p = 0.0002). Sensitivity and specificity using this cutpoint were 85% and 75%, respectively. Tumor score as a measure of anatomic extent was also found to be a significant predictor of local control. The local control rate for tumors assigned a low tumor score (< or = 5) was 78% (21 of 27) compared to 33% (5 of 15) for tumors assigned a high tumor score (6, 7, or 8) (p = 0.008). A significant decrease in the local control rate was observed for cancers involving the paraglottic space at the false vocal cord level (14 of 16 [88%] vs. 12/26 [46%]) (p = 0.010), cancers involving the face of the arytenoid (15 of 18 [83%] vs. 11 of 24 [46%]) (p = 0.024), and tumors involving the interarytenoid region (25 of 36 [69%] vs. 1 of 6 [17%]; p = 0.020). There were 12 patients with sclerosis of both the ipsilateral arytenoid and the adjacent cricoid cartilage. These patients showed a significant decrease in local control (4 of 12 [33%]). CONCLUSION: Pretreatment CT can stratify patients with T3 glottic carcinoma into groups more or less likely to be locally controlled with definitive RT. The local control rate for these tumors can be improved using a CT-based tumor profile; the ideal CT profile for a radiocurable T3 glottic larynx carcinoma is volume < 3.5 cm3 and no or single laryngeal cartilage sclerosis.     

Encephalitis in mice inoculated intranasally with an influenza virus strain originated from a water bird

A retrospective chart review of 43 patients who underwent technetium 99m (Tc-99m) sestamibi scans from June 1995 to January 1997 was performed. Only those who underwent subsequent parathyroid exploration with excision were included in the study. Twenty subjects (13 women and seven men) were included in the study. Ages ranged from 21 to 84 years (mean, 58 years). All patients had laboratory values and clinical findings consistent with primary hyperparathyroidism. Two patients had preoperative magnetic resonance imaging (MRI) scans (one patient with recurrent disease), and one had a preoperative computed tomography (CT) scan. The remaining patients had the sestamibi scan as the only preoperative localization study. There were 18 pathologic diagnoses of parathyroid adenoma and two of parathyroid hyperplasia. Sestamibi failed to correctly identify the location of the parathyroid lesion in two cases. In 18 cases the preoperative sestamibi scan correctly localized the lesion, a predictive value of 90%. We conclude that the Tc-99m sestamibi scan is an accurate preoperative tool that can be used as a single modality to localize parathyroid adenomas.     

Cost implications of different surgical management strategies for primary hyperparathyroidism

BACKGROUND: Controversy exists about optimal management of patients with primary hyperparathyroidism. To date, no studies have explored the cost implications of variation in practice. METHODS: Results from a national survey of endocrine surgeons were combined with results from a survey of endocrinologists and financial data from Medicare. Patterns of use of resources were identified, annual costs for the surgical management of primary hyperparathyroidism in the United States were calculated, and the financial impact of variation in practice was estimated. RESULTS: Survey respondents (n = 109) were experienced endocrine surgeons, performing an average of 33 parathyroidectomies annually. Seventy-five percent of patients undergo localization before initial exploration for primary hyperparathyroidism. In order of preference, these studies were sestamibi (43%), ultrasonography (28%), and sestamibi with single-photon emission computed tomography (26%). Although there is variation in preoperative and postoperative practice, in-hospital costs have the greatest influence on total cost. An estimated $282 million is spent annually in the United States on operations for primary hyperparathyroidism. National health expenditures could range by more than $70 million, depending on whether management strategies involving low or high use of resources are employed. CONCLUSIONS: Substantial variation among endocrine surgeons in the management of primary hyperparathyroidism has important cost implications. Implementation of evidence-based guidelines to optimize clinical and economic performance should be considered.     

Collagen deposition and mechanical strength of colon anastomoses and skin incisional wounds of rats

BACKGROUND: The purpose of this study was to prospectively evaluate parathyroid localization using technetium-99m-sestamibi (MIBI). STUDY DESIGN: Technetium-99m-sestamibi scintigraphy was performed in 124 patients with hyperparathyroidism and the results were correlated with serum calcium and parathyroid hormone (PTH) levels, weight, location, and pathology of parathyroid tissue, and associated thyroid abnormalities. RESULTS: Hyperparathyroidism was primary in 118 patients, secondary in four patients, and tertiary in two patients. The parathyroid pathology was a solitary adenoma in 95 patients (77 percent), double adenoma in five (4 percent), hyperplasia in 14 (11 percent), carcinoma in one (1 percent), and unconfirmed in nine (7 percent) who underwent noncurative parathyroidectomy. Associated thyroid disease was present in 29 (23 percent) patients. Fourteen patients (11 percent) had undergone previous parathyroid exploration. The mean calcium level was 11.4 +/- 0.8 mg/dL (range, 8.3 to 13.7 mg/dL) and the mean adjusted PTH level was 395 +/- 702 (range, 70 to 4,331). The sensitivity and positive predictive value of MIBI scintigraphy were 81 and 89 percent, respectively, in patients with a solitary adenoma and 37 and 100 percent, respectively, in patients with multiglandular disease. The mean adjusted PTH level was higher in patients with true-positive scans compared with false-negative scans (440 +/- 628 compared with 243 +/- 499, p > 0.05). The mean adenoma weight was 1,877 +/- 3,212 mg in patients with a true-positive scan compared with 485 +/- 296 mg with a false-negative scan (p > 0.05). CONCLUSIONS: The sensitivity and positive predictive value of MIBI scintigraphy is comparable to or better than the results reported for other localization procedures. Its lack of sensitivity for detection of multiglandular disease precludes its use in lieu of routine bilateral neck exploration in the management of patients with hyperparathyroidism.     

Sestamibi scanning is inadequate for directing unilateral neck exploration for first-time parathyroidectomy

OBJECTIVE: To determine whether technetium Tc 99m sestamibi scanning is accurate enough to allow surgeons to perform unilateral neck exploration for first-time parathyroidectomy in patients with primary hyperparathyroidism. DESIGN: Retrospective review. SETTING: University tertiary care center. PATIENTS: Forty patients with primary hyperparathyroidism who underwent sestamibi scanning before first-time parathyroidectomy, of whom 28 had single adenomas, 9 had multiple adenomas, and 3 had hyperplasia. INTERVENTIONS: All 40 patients underwent bilateral neck exploration with identification of 4 parathyroid glands. MAIN OUTCOME MEASURES: We compared the results of preoperative sestamibi scanning with operative and histologic findings. We then used these data to calculate the projected success rates of parathyroidectomy if unilateral neck explorations had been performed based on the results of sestamibi scanning, instead of bilateral explorations. RESULTS: Sestamibi scanning was correct in 20 (71%) of 28 patients with single adenomas, 4 (44%) of 9 patients with multiple adenomas, and 0 (0%) of 3 patients with hyperplasia. If unilateral neck explorations had been performed on the basis of localization by sestamibi scanning, parathyroidectomy would have failed in 4 (10%) of 40 patients. CONCLUSIONS: Sestamibi scanning, although helpful, is inadequate for directing unilateral neck exploration for first-time parathyroidectomy. Surgeons who perform unilateral neck exploration based on the results of sestamibi scanning will record a higher failure rate and incur higher costs than those who perform bilateral neck exploration for first-time parathyroidectomy.     

The role of thyroid resection during reoperation for persistent or recurrent hyperparathyroidism

BACKGROUND: The role of "blind" thyroid lobectomy in the surgical management of patients with persistent or recurrent primary hyperparathyroidism is not known. We reviewed our experience with reoperation for hyperparathyroidism to determine the utility of blind thyroid resection in this setting. METHODS: From 1982 to 1995, 269 patients underwent reoperation for hyperparathyroidism at our institution. All patients had biochemical confirmation of hyperparathyroidism and underwent noninvasive and if necessary invasive localization studies. Patients who underwent thyroid lobectomy in an attempt to extirpate the hyperfunctioning parathyroid gland form the basis of this report. RESULTS: Thirty-two of 269 patients (12%) underwent thyroid lobectomy to remove a parathyroid gland. Intrathyroidal parathyroids were confirmed in 19 of 32 patients (59%). In 18 of 19 patients (94%), preoperative or intraoperative ultrasonography correctly identified an intrathyroidal lesion suspicious or a parathyroid. Only 1 of 6 patients (17%) undergoing a blind thyroidectomy had an intrathyroidal gland identified. Ultrasonography had a sensitivity of 95% and a negative predictive value of 99.5% in detecting an intrathyroidal parathyroid gland. CONCLUSIONS: The prevalence of an intrathyroidal parathyroid gland in our series is low (19 of 269, 7%). Ultrasonography can be used reliably to select patients for thyroid resection, reducing the need to perform a blind thyroid lobectomy and avoiding the potential morbidity of thyroid resection in this clinical setting.     

Trial of new intraocular lens power calculation following phototherapeutic keratectomy]

Thirty-one men (age range, 46-76 years; mean age, 64.8 years) with intrathoracic masses suggesting possible malignancy on the basis of chest radiography or CT underwent preoperative Tc-99m MIBI SPECT examinations. Diagnosis was confirmed on pathologic examinations of samples obtained either at thoracotomy, esophagectomy, or by biopsy. Twenty-five patients had primary lung cancer, including squamous cell carcinoma, large cell carcinoma, adenocarcinoma, and small cell carcinoma. Two patients had lymphomas with spread to the mediastinum, and three patients had extrathoracic primary cancers (one squamous cell carcinoma of esophagus, one squamous cell carcinoma originating from a head and neck tumor, and one metastatic mediastinal leiomyosarcoma). One patient with a tuberculoma had negative results of the Tc-99m MIBI examination. Tc-99m MIBI had a 86.7% sensitivity rate, a 0% false-positive rate, and a 100% positive predictive value to detect malignant intrathoracic masses. There was a 13% false-negative rate, however, suggesting that MIBI-SPECT may underdiagnose malignant lesions. SPECT findings of these 31 patients can be classified as 1) mass with increased uptake, n = 23; 2) ring-like appearance of increased uptake, n = 3; 3) mass with absent uptake, n = 4; and 4) photon-deficient mass, n = 1. Absent uptake in patients with mass lesions could be explained by necrosis of the lesion (caseation necrosis or massive tumor necrosis with or without bleeding). Most malignant intrathoracic masses are Tc-99m MIBI avid and may be detected with a high degree of sensitivity and with an excellent positive predictive value. A positive MIBI scan may help in the clinical diagnosis of malignancy. The use of Tc-99m MIBI could serve not only as a tumor imaging agent, but also may be used to determine the extent of spread and potentially the chemotherapeutic responsiveness of a tumor.     

Surgical management of primary hyperparathyroidism in multiple endocrine neoplasia types 1 and 2

BACKGROUND: The surgical management of primary hyperparathyroidism in multiple endocrine neoplasia type 1 (MEN 1) remains controversial. In addition, the rarity of MEN 2A-related hyperparathyroidism has not allowed for a separate strategy for this condition. This study examines our surgical experience with MEN 1- and MEN 2A-related hyperparathyroidism and attempts to define a rational therapeutic approach to each. METHODS: Between 1970 and 1991, 124 patients underwent surgery for MEN-related hyperparathyroidism at our institution. Primary cervical explorations were performed in 84 patients with MEN 1 and 18 with MEN 2A. An additional 22 patients with MEN 1 underwent reoperative surgery. All patients with MEN 2A underwent concomitant thyroidectomy for medullary thyroid cancer. RESULTS: Compared with patients with MEN 1, patients with MEN 2A, had a lower preoperative serum Ca2+ level and fewer symptoms or complications of hypercalcemia. Multiple gland disease was evident in 90% and 83%, respectively, of patients with MEN 1 and MEN 2A. Primary explorations in patients with MEN 1 resulted in surgical cure in 94%, persistent hypercalcemia occurring in no patient undergoing subtotal resection compared with 17% of patients in whom more conservative resections were performed (p = 0.005). In patients with MEN 1, 10-year recurrence of hypercalcemia was 16% for primary explorations and 30% for reoperative procedures. In contrast, all patients with MEN 2A, whether treated by total, subtotal, or lesser resections, were cured after surgery and none had recurrence during a median follow-up of 5.8 years. CONCLUSIONS: In MEN 1 the surgical principles should be (1) identification of all four glands, (2) subtotal resection to ensure cure and facilitate possible reoperation, and (3) excision of supernumerary thymic glands. In MEN 2A we should identify and resect all enlarged glands for cure, but routine subtotal resection need not be performed because this condition is readily cured and recurrence is rare.