Oscillatory Carreau flows in straight channels.

The present paper studies the oscillatory flow of Carreau fluid in a channel at different Womersley and Carreau numbers. At high and low Womersley numbers, asymptotic expansions in small parameters, connected with the Womersley number, are developed. For the intermediate Womersley numbers, theoretical bounds for the velocity solution and its gradient, depending on the problem parameters, are proven and explicitly given. It is shown that the Carreau number changes the type of the flow velocity to be closer to the Newtonian velocity corresponding to low or high shear or to have a transitional character between both Newtonian velocities. Some numerical examples for the velocity at different Carreau and Womersley numbers are presented for illustration with respect to the similar Newtonian flow velocity.

[Retrosternal thyroid goiter: 20 years experience].

Retrosternal localization of thyroid pathology is not rare. We present a retrospective 20-years' research on 4225 patients with different thyroid diseases. 803 of them were with a different level/stage) of retrosternal localization of the gland. Our analysis reveals that the possibility of malignancy and difficult diagnosis make surgical treatment obligatory. It should be performed only by experienced in thyroid surgery specialists.

[Subtotal resection of thyroid gland - optimal method for threatment of Bazedow disease. Prognosis].

Subtotal thyroidectomy is a widely accepted surgical procedure for Basedow disease. The purpose of this work is to evaluate functional long-term results and determine predictive prognostic factors of postoperative thyroid function. This is a retrospective study conducted on 207 patients with Basedow disease undergoing subtotal thyroidectomy during the period 1983-2004. Predictive prognostic factors of final thyroid status were investigated and probability of hypothyroidism during the years of follow-up was obtained by the Kaplan-Meier method. Surgery controlled hyperthyroidism in 199 out of 207 patients (97%). The probability of hypo-, eu-, and hyperthyroidism at 5 years was 63%, 36%, and 2%, respectively. No statistical change in thyroid function occurred in the follow-up after 5 years. Multivariate analysis by a logistic ordinal regression analysis showed that weight of the remnant, age, and gender seemed to influence long-term thyroid function. The higher rates of euthyroidism were obtained when the remnant weight was between 6 and 8 g. No recurrence or persistence of hyperthyroidism occurred with remnant weights under 5 g. Subtotal thyroidectomy controlled hyperfunction symptoms in 97% of our patients. Cure (euthyroidism) of Basedow disease patients should be attempted by leaving a thyroid tissue remnant between 6 and 8 g. Even more significant, our results suggest that euthyroidism rates could be improved by leaving a smaller remnant in elderly women and greater remnants in young men. No need for long term medical therapy is emphasised.

[Medullary thyroid carcinoma--current surgical aspects. Overview and retrospective analysis of 22 cases].

BACKGROUND: Medullary thyroid carcinoma (MTC) accounts for 5% to 10% of all thyroid malignancies. Approximately 75% of cases are sporadic. Familial forms of medullary thyroid carcinoma account for the remaining 25% of cases--MEN IIa, MEN IIb and FMTC. METHODS: Retrospectively 22 cases of medullary carcinoma of thyroid gland were analysed. Total thyroidectomy with selective lymph dissection was performed in all patients. RESULTS: 18 patients were with sporadic form of medullary thyroid carcinoma, 4--with FMTC; 21 were with primary carcinoma, 1--with recurrent carcinoma Mean age--32 years (22-59). At the follow-up control (max 10 years) there is no evidence of disease recurrence. CONCLUSION: Recent advances in genetic testing allow early diagnosis and treatment of familial MTC syndromes. Despite some advances in treatment, optimal management is still controversial. Total thyroidectomy with selective lymph dissection remains the choice of surgical treatment. In the familial forms medullary carcinoma is associated with well-characterized, germline mutations in the RET protooncogene. Both genetic and biochemical screening are of essential significance for early diagnosis and adequate and optimal surgical treatment.

[Surgical treatment of creeping infections of the flexor foot tendons in diabetic patients]. / Khirurgichno lechenie na pulziashtite infektsii po fleksornite sukhozhiliia na khodiloto pri diabetnobolni.

UNLABELLED: The creeping infections of the flexor foot tendons are a common reason for amputation of limbs in diabetic patients. Usually the process starts from the fingers and spreads through their long flexors. METHODS: Of the total of 149 operated patients, 49 underwent selective removal of the m. flexor hallucis longus tendon, and amputation of the 1st finger. The long flexors of the foot fingers were totally removed through a transmethatarsal amputation in 78 patients, and in 22 the long flexor tendons of the 4 lateral fingers were selectively removed through an oblique foot resection. After this type of surgical operations, limb amputation as a result of losing control over the suppurative-gangrenous process, became necessary in 7 patients. CONCLUSIONS: The infection spreading through the long flexors of the foot fingers in diabetic patients is a serious surgical complication that can only be treated surgically. The method of selective resection and removal of the infected long flexors of the foot fingers allows to avoid the limb amputation in most patients. Following this type of surgical interventions the foot biomechanics and the steadiness of the patient is inconsiderably disrupted.

[Thymectomy for myastenia gravis: 25-year experience]. / Timektomiia za miasteniia gravis: 25-godishen opit.

OBJECTIVE: Thymectomy is considered an effective therapeutic option for patients with myasthenia gravis (MG). We reviewed our 25-years experience with surgical treatment of MG with respect to long-term results and factors affecting outcome. METHODS: Between 1978 and 2002, we performed 232 thymectomies for MG. Fifteen patients were lost to follow-up; the remaining 217 form the object of our study. 32 patients (28.4%) had thymoma. Myasthenia was graded according to a modified Osserman classification: 51 patients (23.5%) were in class I, 81 (37.3%) in class IIA, 52 (24%) in class IIB, 26 (12%) in class III and seven (3.2%) in class IV. Mean duration of symptoms before the operation was 14 +/- 10 months. Fifty-eight thymectomies for thymoma were performed through a median sternotomy and four through a clamshell incision. Forty-six thymectomies for non-thymomatous MG were performed through a standard cervicotomy, 155 procedures through a partial upper sternal-splitting incision and eight through a complete median sternotomy. RESULTS: Operative mortality was 0.92% (two patients). After a mean follow-up of 119 months, 77% of all patients improved their clinical status (26% without medications and asymptomatic; 45% with a reduction of medications and/or clinically improved); 39 (18%) have a stable disease with no clinical modifications; 12 (5%) presented a deterioration of their clinical status with worse symptoms, required more medications, or both. Thirteen patients (6%) died because of MG (mean survival 34.3 +/- 3.6 months). The presence of a thymoma negatively influenced the prognosis. Younger patients showed a more favorable outcome as well as patients with a shorter duration of symptoms before the operation; patients with lower classes of myasthenia showed a higher rate of remission. CONCLUSIONS: Thymectomy is effective in the management of patients with MG at all stages with low morbidity. Patients with thymoma present a less favorable outcome.

[Possibilities of retroperitoneal endoscopic surgery in treatment of adrenal diseases]. / Vuzmozhnosti na ednoskopskata khirurgiia v lechenieto na zaboliavaniiata na nadbubrechnite zhlezi.

UNLABELLED: After introduction of the transperitoneal endoscopic adrenalectomy in 1992 and retroperitoneal adrenalectomy (RA) in 1994, the both techniques were widely accepted in the routine surgery practices. Now some authors described them as a "golden standard" in the surgical treatment of adrenal disorders. MATERIAL AND METHOD: 34 retroperitoneal endoscopic adrenalectomy were performed in our clinic for the period of May 1996-December 2002. RESULTS: The mean operating time was 125 minutes (45-220 min.) The average itraoperative blood loss was 70 ml. Only in one case the blood loss was 300 ml, causing conversion to open adrenalectomy. In 6 cases we converted to open adrenalectomy for other reasons--17.6%. In the last 15 cases we had no need of conversion to open adrenalectomy. Intraoperative complications were minor--2 cases (5.88%). Consumption of analgesics was low. Hospitalization period was 3 days. CONCLUSIONS: In summary, EA is associated with fewer complications than have been reported with OA. Despite the limitations of retrospective analysis, the results of this technique are very impressing in relation to diminishing the operative trauma, postoperative pain syndrome and faster recovery. EA is to become a method of choice in surgical treatment of the benign adrenal disorders.

[Retrospective analysis of the results of surgical treatment of 407 patients with differential thyroid gland cancer over a period of 23 years]. / Retrospektiven analiz na rezultatite ot khirurgicheskoto lechenie na 407 bolni s diferentsiran rak na shtitovidnata zhleza za 23-godishen period.

Over a period of 23 years (1980-2002) 407 cases of differential thyroid gland cancer were operated, monitored and analyzed at the Endocrine Surgery Clinic of Alexandrovska University Hospital. Of them 71.7% were monitored over a period of more than 10 years (up to 23 years), and 39.3% were monitored between 15 and 23 years. The youngest patient was 12 years old, and the oldest--78 years old. All patients were at a T(1-3) N(a-b) M0 stage. 308 (75.7%) patients had papillary carcinoma, and multi-centric localization was established in 3.9%, while capsular invasion and unilateral lymph-nodular metastases--in 6.2% of those patients. Follicular cancer was found in 24%, and vascular invasion--in 15.1%. 72.4% of the patients fall within the low-risk age groups (women under 50 years of age and men under 40). The treatment of 22.1% (90) of the patients comprised thyroidectomy with a follow-on 131J therapy. 77.9% (317) of the patients underwent radical thyroid gland resections of various size. Bilateral subtotal resections were applied most often--in 64.5% of all cases, and the rest of the patients underwent lobectomy with contra-lateral subtotal resection. The recurrence rate among the patients treated with radical resections is 6.1%, mainly within the high-risk age group. No correlation was established between the recurrence rate and the type of organ-saving surgery. In the group of patients treated with thyroidectomy and 131J, recurrences of the disease were established in 16.2%, again mainly within the high-risk age group. Remote metastases and mortality were established in 3% and 2.5% respectively. In conclusion, preference is given to organ-saving surgical treatment of differential thyroid gland cancer, and it is recommended that in the high-risk age groups the operations be of a broader scope.

[Surgical treatment of the diabetic septic foot]. / Khirurgichno lechenie na diabetnoto septichno khodilo.

An opening and a major stage of the diabetic septic foot surgical treatment is the primary surgical processing that is usually combined with amputation of separate fingers or with various types of transmetatarsal amputations. Out of the total of 379 operated patients 35.7% underwent amputation of separate fingers, combined with resection of the metatarsal bone head. 18.3% of the patients underwent transmetatarsal amputations by Sharp with plantar lambo shaping, and 14.9% had oblique resections with dermatological plastic surgeries. As a result of this treatment the foot amputations were reduced to 5.7%. The extended use of conservative treatment combined with primary surgical processing is a major precondition for restricting the suppurative gangrenous process. Staged surgical treatment ensures a drastic decrease in the number of foot amputations. The reconstruction plastic foot operations enable the shaping of an adequate foot area with good biomechanics.

[Differentiated thyroid cancer--a study of the pathomorphological variants in 216 patients]. / Diferentsiran rak na shtitovidnata zhleza--prouchvane na patomorfologichnite varianti pri 216 bolni.

Two-hundred sixteen patients presenting differentiated carcinoma of the thyroid gland are subjected to operative treatment over the period 1980 through 1993. The distribution of cases by histological type is as follows: papillary carcinoma--127 cases, follicular--58, and mixed type (papillary-follicular)--thirty one. In the group presenting papillary lesions, infiltration of the capsula is noted in nine cases, multifocal location--in five, and microcarcinoma--in twenty three. In the follicular carcinoma group a markedly expressed vascular invasion is established in four cases, multifocal location--three, and microcarcinoma--five. Assessment of the morphological patterns of differentiated thyroid carcinoma reveals a marked predomination of noncomplicated histologic variants, enabling the wide use of minor conservative operative procedures, compared to thyroidectomy, with a positive outcome. Over he past few decades, the incidence of differentiated forms of thyroid gland carcinoma shows an increase, and nowadays it caries in the range 60 to 90 per cent. Papillary forms are prevailing, while follicular carcinomas are detected in 8 to 20 per cent of cases. An overall shift of morbidity towards younger ages and female gender is observed.

[Hypophyseal-thyroid function following partial thyroid resections for euthyroid struma nodosa]. / Prouchvane na khipofizno-tireoidnata funktsiia sled partsialni rezektsii na shtitovidnata zhleza po povod nodozni eutireoidni strumi.

The serum levels of svT3, svT4, TTH, T3 and T4 are evaluated at two, six and twelve months after partial resection of the thyroid gland in patients with euthyroid struma nodosa. The patients are divided up in two groups: group one--given hormonal substitution therapy, and group two--untreated. The results are estimated with a special reference to the need of hormonal administration in view of precluding recurrences.

[The incidence and morphological aspects of thyroid cancer]. / Chestota i morfologichni aspekti na raka na shtitovidnata zhleza.

A total of 10,736 biopsy specimens presenting diverse thyroid gland pathology are studied over the period 1974 to December 1993. The histopathological investigation shows that 5.45 per cent of them (n = 585) are with carcinoma. Comparative analysis of the incidence of thyroid carcinoma in the series reviewed, covering the two decades, points to a tendency of the incidence rate to augment from 4.03 per cent in the first decade to average 6.63 per cent in the second decade of study, with a frequency peak reached in the period 1986-1993. There is a clearcut tendency of the incidence of malignant conditions of the thyroid to rise among younger age groups. A markedly expressed tendency of the number of patients with papillary carcinoma of the thyroid, affecting mainly women and younger persons, to increase is also documented.

[The routine immunohistochemical diagnosis and surgical treatment of medullary carcinoma of the thyroid]. / Rutinna imunokhistokhimichna diagnoza i khirurgichno lechenie na medularniia kartsinom na shtitovidnata zhleza.

Over the period 1977 through 1988, in the Research Institute of Surgery--Medical Academy a total of 372 patients undergo primary operative management for thyroid gland carcinoma. Medullary carcinoma is discovered in 18 patients of the series (4.8 per cent). The preoperative diagnosis is supplemented by thyroscintigraphy with 131iodine or technetium Tc 201. After 1981, calcitonin and carcinoembryonic antigen (CEA), specific medullary thyroid carcinoma (MTC) markers, measurements are routinely done, with substantially elevated levels in the patients under study being found, in those with metastases inclusive. Presumably, the preoperative diagnosis medullary thyroid carcinoma is very difficult, and only a combined approach, including thyroidectomy with ensuing iodine radiotherapy, may account for a good survivorship. Postoperatively, all patients with MTC diagnosis are regularly tested for serum calcitonin and CEA levels. The carefully taken family history and questioning of the patients allows to differentiate familial from cases from sporadic neoplasms.

[Early thymectomy in the treatment of myasthenia gravis]. / Rannata timektomiia pri lechenieto na myasthenia gravis.

Over a 10-year period, 1983 through 1992, in the clinic of endocrinologic surgery--Alexander Hospital, Sofia, 89 patients with myasthenia gravis (MG), 57 women and 32 men, are subjected to operative treatment--thymectomy. The mean age in women is 32 years (range 19 to 68), and in men--45.6 years (range 25 to 70). Two age-related distributions in the series are impressive--in female patients the peak is between 20 and 30 years, whereas in men--between 45 and 55 years. The operative intervention consists in total thymectomy. Preference is given to the trans-sternal median access to the thymus gland. In the complex therapeutic approach to MG are included also a number of drugs and other agents--corticosteroids, anticholinesterase agents, immunosuppressives and the like. Patients undergoing operative thymectomy are usually given preoperative treatment with anticholinesterase drugs for different periods of time. Operation is undertaken only in stable condition of the patients. Good postoperative results are recorded in 57 per cent of those operated by the first year, with a satisfactory improvement in 29.2 per cent of them. In the third group (13.4 per cent) the postoperative results are poor, and treatment is proceeded with anticholinesterase drugs or immunosuppressives. The average follow-up term is 44.7 months. The delay in improvement is typical of patients with longer duration of the complaints, but it may be attained within 2, 3 or 5 years postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

[The surgical treatment of myasthenia gravis--the authors' own experience]. / Khirurgichno lechenie na myasthenia gravis--sobstven opit.

Proceeding from personal experience accumulated hitherto, the indications for both operative treatment of MG, and choice of the most adequate preoperative preparation and timing of thymectomy, are precisely determined. Pathohistologic findings and postoperative results in 47 patients, thymectomized in the period 1989 to 1994, are followed up and analyzed. The inference is reached that preliminary stabilization of the patient's condition with anticholinesterase drugs, and early and total thymectomy are essential for the successful outcome of treatment. It is preferable that thymectomy is done within six months of the occurrence of complaints or making the diagnosis.

[Struma nodosa and cancer of the thyroid]. / Struma nodosa i rak na shtitovidnata zhleza.

The disputable issue of the pathogenetic relation between struma nodosa and thyroid gland carcinoma is discussed. A total of 234 patients with definitive diagnosis thyroid carcinoma, operated in the clinic of endocrine surgery--Higher Medical Institute, Sofia, are retrospectively analyzed. Clinical, past history and pathomorphologic data are considered--123 patients present papillary carcinoma, 67--follicular, and 42--mixed form. All patients undergo operative management over the period 1980 through 1991. Later, to the aforementioned group are added further 50 patients with carcinoma of the thyroid, treated from 1991 to late December 1992, and thus the total number amounts to 284 cases--153 papillary, 79 follicular and 52 mixed forms, respectively. In 67.2 per cent of the cases the thyroid carcinoma presents clinical patterns of a solitary node, in 27.8 per cent--node of multinodular struma, and in 4.9 per cent--formation associated with another thyroid disease. Multifocal location is established in five cases. As shown by the pathomorphological study in 18 per cent of the cases it is a matter of a combination--thyroid carcinoma and struma multinodosa, and in 1.2 per cent of the cases only there is conclusive evidence of solitary adenoma malignization. The obtained results lead to the inference that thyroid carcinoma deriving from the nodose structures of the gland is an exception, rather than rule.