Biomedical subjects

Mark S Sywak

Publications and source records attributed to Mark S Sywak.

11 recordsLinked to original sources

PubMed2006

New era: prophylactic surgery for patients with multiple endocrine neoplasia-2a.

BACKGROUND: The surgical management of patients with multiple endocrine neoplasia-2A (MEN-2A) continues to evolve with specific genotype-phenotype correlations allowing for a more tailored approach. In this study, we report the surgical management of one of the largest MEN-2A families with a rearranged during transfection (RET) codon 804 mutation. METHOD: This is a cohort study comprising all at-risk kindred within a single known MEN-2A family. Prophylactic total thyroidectomy with lymph node dissection was recommended to all mutation carriers aged 5 years and older. RESULTS: There were a total of 48 at-risk individuals in the MEN-2A kindred, with 22 patients undergoing thyroidectomy after appropriate preoperative evaluation. A total of 9 patients had medullary thyroid cancer including 5 with a normal preoperative calcitonin level. A total of 11 patients had C-cell hyperplasia and 7 showed histological evidence of parathyroid disease. Only the index case had a phaeochromocytoma. CONCLUSIONS: Genetic testing for germline mutations in the RET proto-oncogene has allowed precise identification of affected RET carriers and provided the opportunity for prophylactic or 'preclinical' surgery to treat and in fact to prevent medullary thyroid cancer. This concept of prophylactic surgery based on a genetic test is likely to be applied more widely as the tools of molecular biology advance.

Adolescent↗

PubMed2006

Use of the ligaSure vessel sealing system in laparoscopic adrenalectomy.

Laparoscopic adrenalectomy is the operation of choice for benign adrenal lesions. During laparoscopic surgery, vessels are usually ligated with diathermy, ligaclips, staplers or ultrasonic coagulators. Use of the electrothermal bipolar vessel sealer (LigaSure; Valleylab, Boulder, CO, USA) has recently been described in a variety of procedures, not including adrenalectomy. This article is a retrospective study of 28 patients undergoing laparoscopic adrenalectomy within the University of Sydney Endocrine Surgical Unit at the Royal North Shore Hospital using the LigaSure vessel sealing system. Between July 2004 and August 2005, 28 consecutive patients underwent laparoscopic adrenalectomy using the LigaSure vessel sealing system to divide feeding adrenal vessels as well as the adrenal vein. There were no bleeding complications. The LigaSure vessel sealing system can be safely used to secure haemostasis, including division of the adrenal vein, in laparoscopic adrenalectomy.

Adrenalectomy↗

PubMed2005

Phaeochromocytoma: current concepts.

The discovery of novel mutations in genes encoding succinate dehydrogenase subunits has revealed that familial phaeochromocytomas are much more common than previously thought. Genetic screening should be offered to patients with apparently sporadic phaeochromocytomas and their first-degree relatives. An increasing proportion of phaeochromocytomas present preclinically on genetic testing or as "incidentalomas" on abdominal imaging, rather than with classic symptoms and signs. Clinical suspicion should prompt measurement of plasma levels of free metanephrine or 24-hour urinary catecholamine and metanephrine levels, followed, if positive, by tumour localisation studies. With appropriate perioperative care, surgical management of phaeochromocytomas is safe and effective. Most tumours can be removed laparoscopically.

Adrenal Gland Neoplasms↗

PubMed2005

Safety and feasibility of thyroid lobectomy via a lateral 2.5-cm incision with a cohort comparison of the first 50 cases: evolution of a surgical approach.

BACKGROUND AND AIMS: Over 500 minimal-access parathyroidectomies (MIPs) have been performed in our unit, and, from these, a technique for thyroid resection has evolved. We present a report on the evolution of minimal-access thyroid surgery (MATS) and compare the results with those from a cohort of patients operated on prior to the use of MATS. METHODS: We reviewed the evolution towards the MATS technique. The results of the MATS procedures were compared with those from an equal number of consecutive patients undergoing conventional lobectomy prior to the use of MATS. RESULTS: Fifty patients (mean age 45.6 years) underwent MATS between March 2002 and May 2004. The mean nodule diameter was 18.5 mm. In the MATS group there was one recurrent laryngeal nerve (RLN) injury, two temporary RLN neuropraxias, which recovered, and one haematoma. The control group (mean age 47.9 years) had a mean nodule size of 22 mm. In the controls there was one temporary RLN neuropraxia, which recovered, and two haematomas-P>0.05 (Fisher's exact test) for all the complications. CONCLUSIONS: MATS has evolved from an experimental approach into a safe and feasible surgical procedure based on the same operative approach as used for MIP. It provides an alternative to open thyroid surgery in appropriately selected cases.

Adult↗

PubMed2005

Parathyroid autotransplantation during total thyroidectomy--does the number of glands transplanted affect outcome?

Parathyroid autotransplantation is a technique for ensuring the continued function of parathyroid tissue at the time of total thyroidectomy (TT). The aim of this study was to ascertain whether the number of parathyroids transplanted affects the incidence of temporary and permanent hypoparathyroidism. A retrospective cohort study included all patients undergoing a TT in a single unit between July 1998 and June 2003. The number of parathyroids transplanted, the final pathology, and the incidence of temporary and permanent hypoparathyroidism were documented. Fisher's exact test was used for statistical analysis. A total of 1196 patients underwent a TT during the 5 years studied. Of these, 306 (25.6%) had no parathyroids transplanted, 650 (54.3%), 206 (17.2%), 34 (2.8%) had 1,2, or 3 glands autotransplanted, respectively. The incidence of temporary hypoparathyroidism was 9.8% for no gland transplants, 11.9%, 15.1%, and 31.4% for 1,2,and 3 gland transplants, respectively (p < 0.05). The incidence of permanent hypoparathyroidism was 0.98%, 0.77%, 0.97%, and 0%, respectively (p = NS). The incidence of temporary hypoparathyroidism was higher when surgery was performed for Graves' disease. Temporary hypocalcemia is closely related to the number of autotransplanted parathyroids during TT. The long-term outcome is not affected by the number of parathyroids autotransplanted. A "ready selective" approach to parathyroid autotransplantation is an effective strategy for minimizing the rate of permanent hypoparathyroidism.

Humans↗

PubMed2005

Simultaneous branchial cleft and thyroid disorders may present a management challenge.

BACKGROUND: Cysts, sinuses or abscesses arising from second, third or fourth branchial cleft remnants may lie either within the body of, or in close proximity to the thyroid gland. Given their infrequent nature they may pose both diagnostic and management challenges for the treating surgeon when they occur in association with thyroid disorders. METHODS: This is a case series. All patients with concomitant thyroid disorders and a branchial cleft anomaly treated in the University of Sydney Endocrine Surgical Unit in the 10-year period 1994-2003 comprised the study group. Patient demographics, clinical presentation, imaging, surgical management, definitive histology and outcomes were documented. RESULTS: Six patients were identified with an age range of 3-76 years and a male : female ratio of 1:5. Five branchial cleft anomalies were left sided, one was right sided. Two patients had second cleft anomalies, both of which were initially thought to represent metastatic lymph nodes in association with thyroid cancer. A further two patients had third cleft abnormalities presenting as suppurative thyroiditis. The final two patients had fourth cleft abnormalities causing intraoperative management problems. CONCLUSIONS: Branchial cleft remnants and anomalies are rare but may occur in association with thyroid disease. They may pose a diagnostic and management dilemma either preoperatively, when mistaken for metastatic thyroid cancer, or intraoperatively when mistaken for a thyroid nodule.

Adolescent↗

PubMed2004

131I-meta-iodobenzylguanidine in the management of metastatic midgut carcinoid tumors.

The management of metastatic neuroendocrine tumors incorporates multimodal therapy with surgery, biotherapy, and chemotherapy. Tumor-targeted therapies using radiolabeled octreotide and metaiodobenzylguanidine (mIBG) represent a novel treatment approach. The aim of this study was to evaluate the effectiveness of 131I-mIBG in the treatment of metastatic midgut carcinoid tumors. survival outcomes were assessed for patients treated at two regional cancer centers and then compared. One center used 131I-mIBG routinely in the management of metastatic carcinoid tumors (center A), and the other did not use this modality (center B). Only patients with histologically proven metastatic carcinoid tumor shown, or thought most likely, to be of midgut origin were included in the study. During the period 1980 to 2002, a series of 58 patients from center A with metastatic carcinoid tumor arising from the midgut underwent multimodality therapy with the addition of 131I-mIBG. Their median age was 64 years. The median dose of 131I-mIBG administered was 6751 MBq, and there was an average of 2.8 treatments per patient. During the same period, 58 patients with metastatic carcinoid were treated at center B with similar multimodality therapy without the use of 131I-mIBG therapy. Their median age was 65 years. Survivals at 3 and 5 years were 77% and 63%, respectively (95% CI 47-75), for group A. The 3- and 5-year survivals for group B were 56% and 47% (95% CI 34-59), respectively. The mean follow-up was 6.6 years for group A and 5.0 years for group B. Although retrospective in nature, this study suggests that the addition of 131I-mIBG therapy to the treatment protocol of patients with metastatic midgut carcinoid tumors prolongs survival.

3-Iodobenzylguanidine↗

PubMed2004

Horner's syndrome in association with thyroid and parathyroid disease.

BACKGROUND: Injury to the cervical sympathetic chain and its consequence, Horner's syndrome, as a result of thyroid pathology or surgical intervention is an uncommon complication. The purpose of the present study was to examine the experience of one endocrine surgical unit with pre and postoperative Horner's syndrome. METHODS: This is a retrospective case series. The study group comprised all patients undergoing thyroid and parathyroid surgery at Royal North Shore Hospital from January 2000 to October 2003 who were identified as having either pre or postoperative Horner's syndrome. Patient demographics, operation performed, underlying pathology and outcomes were evaluated. RESULTS: There were nine cases of Horner's syndrome recorded from a total of 2208 thyroid and parathyroid operations undertaken: three with preoperative Horner's, an incidence of 0.14%, six with postoperative Horner's, an incidence of 0.27%. Patients ranged in age from 22 to 87 years. Two of the three preoperative cases were related to benign pathology, the remaining case having anaplastic carcinoma. Five of the six postoperative cases were related to thyroid malignancy with lymph node dissection; one case was associated with benign parathyroid pathology. CONCLUSIONS: Cervical sympathetic chain injury is a rare complication of surgery for thyroid and parathyroid conditions. The presence of preoperative Horner's does not necessarily indicate an underlying malignancy.

Adult↗

PubMed2002

Increase in presentations and procedure rates for hyperparathyroidism in Northern Sydney and New South Wales.

OBJECTIVE: To examine changes in presentation of primary hyperparathyroidism and rates of parathyroidectomy in Northern Sydney (the Northern Sydney Area Heath Service) and New South Wales (NSW). DESIGN: Retrospective case series January 1962 - December 2001 and audit of the NSW Department of Health inpatient database (1993-1999). SETTING: University of Sydney Endocrine Surgical Unit, Royal North Shore Hospital. PARTICIPANTS: 1613 patients undergoing parathyroidectomy during the study period. MAIN OUTCOME MEASURES: Age-standardised parathyroidectomy rates and indications for surgical intervention. RESULTS: The age-standardised rates of parathyroidectomy for primary hyperparathyroidism in women have increased significantly in Northern Sydney from 0.14 cases per 100,000 in 1976 to 7.7 cases per 100,000 in 1996 (P < 0.001). In NSW there has been an increase in parathyroidectomy rates in women from 5.1 cases per 100,000 in 1993 to 12.3 cases per 100,000 in 1998 (P < 0.001). Osteoporosis was the most common overall indication for surgery in Northern Sydney, accounting for 27% of all cases. The proportion of cases presenting with osteoporosis increased significantly from 4% in 1962-1980 to 34% over the past decade (P < 0.001). CONCLUSIONS: The rate of parathyroidectomy procedures has increased markedly in Northern Sydney and in NSW. The investigation of osteoporosis has led to the diagnosis of primary hyperparathyroidism in an increasing proportion of cases and has contributed to the growing surgical referral rates.

Adult↗

PubMed2002

Do the National Institutes of Health consensus guidelines for parathyroidectomy predict symptom severity and surgical outcome in patients with primary hyperparathyroidism?

BACKGROUND: The National Institutes of Health (NIH) consensus guidelines for parathyroidectomy in primary hyperparathyroidism were developed addressing only the classic symptoms and physiologic markers of hyperparathyroidism. The purpose of this study was to assess whether NIH guidelines predict the severity of all symptoms and the outcome of operation. METHODS: Symptom severity measurements using a disease-specific outcome tool called the parathyroidectomy assessment of symptoms (PAS) scores were previously obtained in patients with hyperparathyroidism. Patients were retrospectively stratified into 2 groups: group A, in which 1 or more of the NIH guidelines were met; and group B. in which operation was performed without any of the NIH criteria. For comparison, group C consisted of patients with non-toxic thyroid disease. PAS scores were collected preoperatively, and at 7 days, 3 months, and 12 months postoperatively. RESULTS: There were 95 patients in group A, 22 in group B, and 58 in group C. The median preoperative PAS scores for group A (354) and B (301) were not significantly different, however, both were more symptomatic than group C (176, P <.01). After parathyroidectomy, patients in both group A and B had a significant improvement in their PAS scores (A=177 and B=130, P <.05). CONCLUSIONS: Patients with no NIH criteria for operation are equally symptomatic compared with those who meet the NIH guidelines. Parathyroidectomy significantly improved these symptoms whether or not the patient met the NIH consensus guidelines.

Adult↗

PubMedDate not supplied

Two hundred consecutive parathyroid ultrasound studies by a single clinician: the impact of experience.

OBJECTIVE: To assess the ability of ultrasound studies, performed by an experienced clinician, to predict surgical findings and provide precise anatomic localization of abnormal parathyroid glands. METHODS: We retrospectively examined 200 consecutive parathyroid ultrasound studies performed by a single experienced clinician in our unit. All patients subsequently underwent parathyroidectomy, with histopathologic confirmation of abnormal parathyroid tissue. The correlation between the ultrasound and surgical findings was assessed. RESULTS: Of the 200 study patients, 197 (98.5%) were cured of their disease at the initial operation. Ultrasound studies correctly predicted the surgical findings in 88% of patients, including 168 of 180 (93%) with single gland disease and 7 of 20 (35%) with multiple gland disease (MGD). In all cases in which a single adenoma was identified, precise information regarding its location relative to adjacent anatomic structures was provided. In 92% of these cases, anatomic details correlated closely with surgical findings. Ectopic and descended superior adenomas were most frequently missed. Patients with two nonlocalizing studies (scintigraphy and ultrasonography) had a >50% likelihood of having MGD. CONCLUSION: In experienced hands, parathyroid ultrasonography is a highly sensitive technique that provides both localization of enlarged parathyroid glands and precise anatomic detail. Thus, in this study, focused parathyroidectomy was possible in 76.5% of patients. MGD remains difficult to diagnose preoperatively. Nonlocalizing studies should alert the surgeon to a high probability of MGD and prompt the performance of 4-gland exploration.

Adenoma↗