Biomedical subjects

R Izquierdo

Publications and source records attributed to R Izquierdo.

At least 19 recordsLinked to original sources

PubMed2000

Is repeated fine-needle aspiration cytology useful in the management of patients with benign nodular thyroid disease?

Management of nonneoplastic thyroid nodules (TN) diagnosed by fine-needle aspiration (FNA) is controversial. While clinical follow-up with repeat FNA for enlarging TN is recommended in some studies, others recommend repeat FNA in follow-up of all benign TN after several months or years, in order to identify possible misdiagnosed malignant lesions. This study was done to determine the usefulness of repeat FNA in patients with benign nodular thyroid disease. We studied 94 fine-needle reaspirations performed on 43 females and 2 males 48.2 +/- 17 years of age with benign nodular thyroid nodular disease. Four patients had 3 consecutive FNAs and 41 patients had 2 consecutive FNAs. All FNAs were carried out by the same endocrinologist in the same thyroid area or by cytopathologists. The average time elapsed between the two consecutive FNAs was 18.3 +/- 11.2 (range, 4-48) months. Of the 45 patients, 23 presented with increase in size of the nodule and the remaining 22 patients did not have any change in size at the time of repeat FNA. Identical cytologic diagnoses were rendered in 39 of the 45 patients who underwent 2 or 3 consecutive FNA. Repeat FNA did not result in detection of any malignant neoplasms. Thyroid resection in 7 patients with increased nodule size and pressure symptoms confirmed the cytologic impressions of benign thyroid nodular disease. Our results show that the routine performance of repeated FNA cytology in the follow-up of patients with benign nodular thyroid disease with or without any clinical changes is of limited usefulness. Clinical factors rather than repeat FNA may hold precedence in surgical management of patients with benign nodular thyroid disease.

Adult↗

PubMed1999

Factors related to the quantity of subgingival calculus in proximal root surfaces.

The aim of this study was to determine the association between the quantity of subgingival calculus and the following factors: type and severity of periodontal disease, age, gender and tobacco consumption. A sample of 622 periodontal patients was studied. The radiographically detectable subgingival calculus in proximal root surfaces was recorded in periapical radiographs, considering the number of surfaces without calculus and the number of surfaces exhibiting deposits equal or greater than I mm. The association between the subgingival calculus and the factors under study was analyzed by distinct non-parametric tests. A statistically significant association was found between the absence/presence of subgingival calculus and the type and severity of periodontal disease (p<0.001), tobacco consumption (p=0.0049) and age (p<0.001). The quantity of radiographically-detectable subgingival calculus increased with increasing age and severity of the disease. However, the reverse association was found in smokers, which presented more surfaces free of calculus (p=0.0377) and less surfaces exhibiting deposits equal or greater than 1 mm. The amount of subgingival calculus decreased as the quantity of tobacco consumed increased (p=0.0129), and such differences were more significant in those smoker patients with severe periodontitis (p= 0.0065). An explanation is presented to justify these latter findings, since most literature supports that the presence of calculus is higher in smokers. According to the results of this study, more radiographically-detectable subgingival calculus in proximal root surfaces was found with increasing severity of the disease, with increasing age and with the absence of tobacco consumption.

Adolescent↗

PubMed1999

Invasive aspergillosis diagnosed by fine-needle aspiration of the thyroid gland.

Invasive aspergillosis has been increasingly recognized as causing significant morbidity and mortality in immunocompromised patients but has never been diagnosed by fine-needle thyroid aspiration. A 24-year-old female with systemic lupus erythematosus presented with cough, shortness of breath, and fever of unknown origin unresponsive to broad-spectrum antibiotics. History and physical examination failed to indicate a source of infection. An 111In white blood cell scan showed thyroid localization. Physical examination revealed a multinodular goiter with a left dominant nodule. Fine-needle aspiration biopsy of a thyroid nodule revealed branching hyphae suggestive of Aspergillus sp. Despite immediate and aggressive treatment with amphotericin B and fluconazole, the patient died of overwhelming infection.

Adult↗

PubMed1999

The role of fine-needle aspiration biopsy in the management of thyroid nodules in children, adolescents, and young adults: a multi-institutional study.

Thyroid nodules in children are extremely uncommon and in most cases present as asymptomatic neck masses. The significance of a thyroid nodule in a child involves the underlying risk of malignancy. The purpose of this study was to assess the validity of results of fine-needle aspiration biopsy (FNAB) of thyroid nodules in the pediatric population and its usefulness in pediatric patient management. FNAB was performed on a total of 57 thyroid nodules from 57 patients between 1992 and 1997. The patients included 46 females and 11 males ranging in age from 9 to 20 years (average 16.5 years). Surgical and/or clinical follow up was available in all patients. FNAB diagnoses included papillary thyroid carcinoma (PTC) (12.3% [7/57]), follicular neoplasm (FN) (15.8% [9/57]), atypical cytology (8.8% [5/57]) and nonneoplastic thyroid (63.2% [36/57]). Surgical follow-up available in all patients with cytological diagnoses of PTC, FN, and atypical cytology revealed malignancy in 13 cases. Of the 36 patients with nonneoplastic cytological diagnosis, surgical excision was performed in 3 patients and the rest were followed up clinically. Surgical excision in these 3 patients revealed follicular carcinoma (FC) (1 case) and multinodular goiter (2 cases). Overall, 14 patients (24.6%) had malignant thyroid lesions, including 11 PTC and 3 FC. In conclusion, the majority of pediatric thyroid nodules are benign. The prevalence of malignancy in pediatric patients with thyroid nodules in our series was 24.6%. High diagnostic accuracy of thyroid FNAB improves selection of pediatric patients requiring surgery.

Adenoma↗

PubMed1998

The effect of twist on microvascular anastomotic patency and angiographic luminal dimensions.

BACKGROUND: Microvascular anastomoses must be constructed perfectly in order to be successful. One of the subtle technical errors that can occur during construction is twisting of the anastomosis. In the present study, we examined the effect of twist on the immediate, 2-h postoperative angiographic dimensions and patency of microvascular anastomoses. MATERIALS AND METHODS: Sixty-four Sprague-Dawley rats were assigned randomly to four groups. The femoral arteries were dissected for a distance sufficient to permit the application of an 8.5-mm-long microanastomotic approximator clamp. Microarteriorrhaphies were performed with twists of 0 degrees, 90 degrees, 180 degrees, or 270 degrees. Patency was assessed 2 h after surgery using transabdominal aortic arteriography with run-off. Measurements were recorded for each anastomosis, as well as for the narrowest and widest diameters of the vessels within 10 mm of the anastomosis. RESULTS: Fifty-nine of the 64 rats had technically satisfactory angiograms which permitted measurement of vascular dimensions. The cross-sectional areas of the narrowest areas and the anastomoses were inversely related to the degree of twist, and were significantly reduced at 270 degrees (P < 0.05). Two-hour patency rates were 86% with 0 degrees twist, 82% with 90 degrees twist, 71% with 180 degrees twist, and 33% with 270 degrees twist. The reduction in patency with 270 degrees twist was statistically significant (P < 0.05). CONCLUSIONS: Twists of 0 degrees, 90 degrees, and 180 degrees did not impair patency at a statistically significant level, but twists of 270 degrees did significantly reduce patency of microvascular anastomoses (P < 0.05).

Anastomosis, Surgical↗

PubMed1998

Pneumothorax in active pulmonary tuberculosis: resurgence of an old complication?

With the recent resurgence of tuberculosis (TB) in western countries, the incidence of complicating secondary pneumothorax has also increased. The work-up and management of this complication differs from that in other types of secondary spontaneous pneumothorax (SSP). Our objective was to assess clinical features and therapeutic modalities of SSP in patients with and without active pulmonary tuberculosis (APTB). All patients diagnosed with SSP seen at the Hospital Xeral of Vigo from January 1990 to June 1995 were candidates for this study. Full clinical, radiological and examinations were performed in all patients. Invasive procedures (thoracic catheter aspiration, thoracoscopy and thoracotomy) and mean hospital stay were compared in patients with and without APTB. Forty-eight patients with SSP were enrolled. Eleven patients (10 males and one female, mean age 30 +/- 11 years) had APTB; and 37 patients (31 males and six females, mean age 49 +/- 20 years) had conditions other than APTB. Chest pain, cough and fever were more frequent in patients with APTB (90% vs 59%; 45% vs 13.5%; 36% vs 5%, respectively). Catheter aspiration was successful in three of 10 (30%) of patients with APTB and in 15/23 (60.86%) of those without APTB. Catheter aspiration time was longer in the former group (25 +/- 22 days vs 13 +/- 11 days, P = 0.17). As initial treatment, thoracoscopy was performed in seven of 37 (18.91%) of those without APTB and in one of 10 (10%) patients with APTB. For patients with unsuccessful catheter aspiration, thoracoscopy was performed in eight of nine (89%) patients without APTB and in none of the patients with APTB. Thoracotomy was performed in only one of nine (11%) without APTB and in four of seven (57%) patients with APTB. Patients with APTB had a longer hospitalization (41 vs 18 days, P < 0.001). We concluded that SSP and APTB was a frequent association in our study. Patients with APTB showed a lesser and slower response to catheter aspiration. Despite severe clinical presentation and demand for more invasive procedures, patients with APTB showed a favourable response.

Acute Disease↗

PubMed1998

The role of ultrasonography-guided fine-needle aspiration biopsy in the management of nonpalpable and palpable thyroid nodules.

The introduction of highly sensitive imaging techniques has made it possible to detect many nonpalpable thyroid nodules (non-PTN). We investigated the value of ultrasound-guided fine-needle aspiration biopsy (US-guided FNAB) as a diagnostic tool in the management of non-PTN as well as palpable thyroid nodules (PTN) that were considered difficult to aspirate without guidance. US-guided FNAB was performed on a total of 119 nodules (71 palpable and 48 nonpalpable) from 119 patients between 1992 and 1996. All available clinical and follow-up data were reviewed. Surgical follow-up was available in 24 cases. The patients included 100 females and 19 males ranging in age from 9 to 81 years (average, 51 years). FNA diagnoses (PTN versus non-PTN) included papillary carcinoma (12.7% [9/71] versus 4.2% [2/48], follicular neoplasm (16.9% [12/71] versus 0%), medullary carcinoma (1.4% [1/71] versus 0%), atypical cytology (5.6% [4/71] versus 2.1% [1/48], non-neoplastic thyroid (63.4% [45/71] versus 85.4% [41/48]) and unsatisfactory (0% versus 8.3% [4/48]). In 2 cases of occult papillary carcinoma, risk factors included radiation exposure (1 case) and a newly developed nodule during follow-up for hypothyroidism (1 case). Subsequent surgical follow-up (24 cases) confirmed the FNA findings, except for a case of Hürthle cell adenoma and 1 of Hashimoto's thyroiditis diagnosed as papillary carcinoma and follicular neoplasm, respectively. US-guided FNAB in most non-PTN are diagnosed as benign. For most patients with non-PTN and without any high-risk factors, a conservative approach such as clinical follow-up may be a more cost effective and logical approach. In contrast, US-guided FNAB is more useful in diagnosing biologically significant lesions in PTN that may be difficult to aspirate without guidance.

Adolescent↗

PubMed1998

Transplantation of lymph node fragments in a rabbit ear lymphedema model: a new method for restoring the lymphatic pathway.

The treatment of lymphedema by medical or surgical means remains a difficult task, and no technique is presently satisfactory. We established a rabbit ear chronic lymphedema model in which sequential lymph node fragments were transplanted to restore lymphatic pathways. Twenty New Zealand White rabbits were divided into two groups of 10 animals. One group served as the control, and the other was the transplantation group. A 3-cm-wide strip of skin and subcutaneous tissue including all the lymphatics was excised circumferentially from the root part of the right ear in each rabbit. The vascular pedicle in the control group was wrapped with a "bridge" strip of skin from the ventral ear to protect it from drying. In the transplantation group, the auricular lymph node was harvested from the contralateral ear, cut into 1- to 2-mm slices, and implanted next to the vascular pedicle where the lymph vessels had been resected. Water displacement measurements in both groups revealed significant edema (p < 0.001) compared with the contralateral ear at 3 days. Peak swelling was observed at 10 days in both groups. Volumes decreased in both groups postoperatively. The volume measured as percentage change in the lymph node transplantation group was significantly lower than in the control group at 2 months and continuing to the end of the experiment (p < 0.001). Indirect lymphographic examination revealed that the distal lymphatic vessels of the control group were increased in number, dilated, and did not allow proximal passage of dye. Light microscopy revealed the vascular pedicle to be surrounded by dense scar tissue in the "bridge." The transplantation group showed free passage of dye through the bridge. Microscopic examination showed regenerated lymphoid tissue with sinuses along the artery and vein of the "bridge." Many channels with a layer of endothelial cells were also noted. Electron microscopy confirmed these sites to be regenerated lymph vessels. Lymphatic tissue can regenerate after fragment transplantation. This lymph tissue seems to regenerate lymphatic vessels that may function for drainage. The results suggest that this simple technique may be applicable in a clinical situation to prevent or treat obstructive lymphedema.

Animals↗

PubMed1997

Topical application of low molecular weight heparin in a rabbit traumatic anastomosis model.

Low molecular weight heparins (LMWHs) are antithrombotic drugs composed of lower molecular weight components of heparin with an apparent molecular weight in the range of 4.0-8.0 KDA. These agents have been used clinically for several years. They have different mechanisms of action compared to heparin, a longer half-life and much higher bioavailability. Anticoagulant drugs such as heparin have been used topically in our previous studies to avoid bleeding complications observed with systemic administration. In this study, low molecular weight heparin (Certoparin, Sandoz) was topically administered in a rabbit ear arterial crush-avulsion thrombosis model and compared with heparin. The animals were divided into three groups: LMWH, heparin and saline control groups. In the LMWH group, the patency rate was 71% (10 of 14) at both 1 and 7 days. The patency rate in the heparin group was 95% (19 of 20) at 24 hrs and 80% (16 of 20) at 7 days. In the saline control group, the vessel patency rate was 17% at 24 hrs and 13% at 7 days. Clotting times such as ACT, PT and APTT performed on samples drawn one hour after drug administration were within the normal ranges for both the control and the treatment groups. The results suggest that topical administration of LMWH prevents the occurrence of thrombosis at the traumatic anastomosis site to a similar degree as heparin.

Administration, Topical↗

PubMed1997

Reconstruction of the heel pad in ankle disarticulation with a free muscle transfer.

An otherwise healthy 17-year-old young man developed bilateral heel pad necrosis due to meningococcemia, adult respiratory distress syndrome, and disseminated intravascular coagulation. Bilateral ankle disarticulation amputations were salvaged by use of a dorsally based local flap on one residual limb and a free muscle transfer to reconstruct the weight-bearing surface of the contralateral residual limb. The case report illustrates two methods of unusual salvage of the end-bearing, weight-bearing surface of the residual limbs in a bilateral end-bearing amputation.

Adolescent↗

PubMed1996

Sonographic signs of breast implant rupture.

OBJECTIVE: This study evaluated sonography as a screening test for breast implant rupture and developed diagnostic criteria for implant rupture. SUBJECTS AND METHODS: Women contemplating implant removal were evaluated prospectively with sonography. Implants were classified as normal, indeterminate, or ruptured. Individual sonographic signs were analyzed for their statistic association with implant rupture. To measure the degree of interobserver variation, static images were evaluated by two different observers. RESULTS: Of 236 implants evaluated, surgical confirmation was available in 78, 22 of which were ruptured and 56, intact. Echogenic noise, multiple discontinuous parallel linear echoes, and echodense aggregates in the implant lumen were statistically associated with rupture. Based on sonographic findings, we classified 34 implants as intact (at surgery: 31 intact, 3 ruptured). We classified 19 as ruptured (at surgery: 11 ruptured, 8 intact). Of the 25 implants we classified as indeterminate, 17 were intact and 8 were ruptured at surgery. Therefore, sonography had a positive predictive value of 58%, a negative predictive value of 91%, a sensitivity of 50%, and a specificity of 55%. Receiver operating characteristic analysis suggests a learning curve effect and no significant interobserver variation. CONCLUSIONS: A normal sonographic result is highly predictive of an intact implant. Thus, sonography is useful in evaluating symptomatic women or women concerned about implant rupture. An indeterminate sonographic result suggests the need for further testing.

Adult↗

PubMed1996

Invasion patterns of advanced temporal bone malignancies.

Primary malignancies of the temporal bone may originate in the external auditory canal, the middle ear, the endolymphatic sac, or the eustachian tube. The surgical treatment of advanced tumors in these regions is strictly dependent upon the radiographic delineation of disease extent and the tumor relationship to adjacent neurovascular structures. Twenty-six cases of stage III or IV squamous cell carcinoma of the temporal bone were retrospectively reviewed to correlate preoperative clinicoradiographic analysis with intraoperative findings. The following patterns of tumor invasion were identified: (a) superior erosion through the tegmen tympani into the middle cranial fossa; (b) anterior extension into the glenoid fossa and infratemporal space; (c) inferior growth through the hypotympanum and jugular foramen; (d) posterior involvement of the mastoid air cells; and (e) medial involvement of the middle ear and carotid canal. While otic capsule erosion was uncommon, several of these patients did present with lower cranial nerve palsies. Complex surgical procedures exist for the en bloc resection of advanced temporal bone cancers. Appropriate operative planning must be based upon a knowledge of potential patterns of tumor extension and meticulous radiographic assessment.

Aged↗

PubMed1995

Comparative study on the use of anticoagulants heparin and recombinant hirudin in a rabbit traumatic anastomosis model.

Antithrombotic drugs, such as heparin, have been used in the clinics for a long time. Heparin acts by binding with antithrombin III to form a complex thereby enhancing the activity of antithrombin III to inactivate coagulation factors IIa, IXa, Xa, XIa and XIIa. Hirudin is a new antithrombotic agent and is reported to be much more powerful than heparin on a gravimetric basis. When both are administered systemically, one of the common complications seen is bleeding. Some previous studies have shown that local vascular endothelial concentrations of heparin are 30 to 7500 times greater than those found in the circulating blood. In order to avoid such complications, topical administration of antithrombotic drugs may be an ideal route of administration. The rabbit ear arterial crush-avulsion thrombosis model was used in this study. The animals were divided into five groups: one control group and four treatment groups which received varying concentrations of heparin and hirudin. In the saline control group, the patency rate was 19.23% at 24 hrs and 15.38% at 7 days. A higher patency rate at 7 days was obtained in groups treated with high concentration of heparin and hirudin. ACT, PT and APTT performed on samples drawn one hour after drug administration were within the normal range in both the control and the treatment groups. Scanning electron microscopy revealed the different extent of the clots on the injured intimal surfaces of the vessels in different groups. The results indicate that high concentrations of topically administered heparin or hirudin minimize the systemic complications and maximize the antithrombotic effects.

Administration, Topical↗

PubMed1995

Modified crush-avulsion anastomosis model on the rat femoral vein.

A crush-avulsion anastomosis model was established on the rat femoral vein. Saline or heparin was used as a luminal topical agent and was allowed to contact the damaged endothelium for 10 min. Patency and coagulation parameters were investigated for 1 week. The heparin treated group had a patency rate of 93% at 1 hr vs. 13% for the saline treated group (P < 0.001). At 7 days, the heparin treated group had an 87% patency vs. 7% for the saline-treated group (P < 0.001). Scanning electron micrography (SEM) provided evidence of the deposition of the components of early thrombosis in the crushed venous wall. In contrast, the SEM of the heparin treated group shows a paucity of any evidence of thrombus. These results indicate that the rat vein crush-avulsion model is a reliable and reproducible thrombosis model with low patency. The methods used with the topical agent may improve the patency rate in crush avulsion injuries.

Anastomosis, Surgical↗

PubMed1995

Nuclear p53 immunoreactivity in papillary thyroid cancers is associated with two established indicators of poor prognosis.

The tumor suppressor protein, p53, protects somatic cells against the accumulation of genomic alterations. Cells harboring mutant or inactivated wild-type p53 protein are at risk for the development of genomic instability. Nuclear accumulation of p53 protein is associated with the stepwise dedifferentiation of papillary carcinoma. We asked whether nuclear p53 accumulation is associated with two known indicators of poor prognosis in papillary carcinoma. We studied 55 consecutive papillary cancers (28 from Russia, and 27 from upstate New York). Nuclear p53 immunoreactivity was assessed using a monoclonal antibody, DO-1, on Formalin-fixed paraffin-embedded specimens. The DNA index was determined by computerized image analysis of Feulgen-stained sections. Nearly all cases were well differentiated and none were associated with distant metastases or extrathyroidal invasion. All primary lesions were less than 4 cm in diameter, and almost all patients were female. Nuclear p53 immunoreactivity was associated with a high-risk group characterized by two known indicators of poor prognosis: age > 50, aneuploid DNA content, or both. In the high-risk group (N = 24) 33% of cases displayed nuclear p53 positivity, compared with only 6% in a low-risk group (N = 31) which lacked both features (P = 0.015, two-tailed Fisher exact test). Nuclear accumulation of immunoreactive p53 protein is associated with two established indicators of poor prognosis in papillary carcinoma of the thyroid. This result is consistent with the idea that aberrations in p53 function are associated with the stepwise loss of differentiation in this cancer.

Adolescent↗

PubMed1995

Reconstructing complex cranial defects with a preformed cranial prosthesis.

Large cranial defects (70 cm(2) or more) of complex geometric shapes (bifrontal or involving supraorbital ridges) that are associated with significant cutaneous contracture or soft tissue loss are challenging to reconstruct. We have treated 10 patients with complex cranial defects through a staged approach. Reconstructing the defect involved several steps. Before each surgery, we constructed a craniofacial prosthesis from polymethyl methacrylate to fit the patient's individual defect. When indicated, adjacent skin was expanded with a subcutaneous tissue expander. Finally, we carried out a cranioplasty and placed the prosthesis. Operative closure of the defect was facilitated by microplate and screw fixation with minimal prothesis contouring. Secure, vital, nontension skin closure was performed with the delayed, expanded local flap. Exposure to free polymer and exothermic reaction was avoided. Cosmetic results in these patients with high-volume, geometrically complex defects were excellent. No complications occurred, and the overall operative time was shortened.

Journal Article↗

PubMed1994

The clinical evaluation of patients with subclinical hyperthyroidism and free triiodothyronine (free T3) toxicosis.

PURPOSE: To develop a strategy to identify cases of endogenous subclinical hyperthyroidism and free triiodothyronine (free T3) thyrotoxicosis in otherwise healthy ambulatory patients. PATIENTS AND METHODS: In a retrospective study we reviewed the records of ambulatory patients who had thyroid stimulating hormone (TSH) levels determined between October 1, 1991 and August 31, 1992. Each patient also had a simultaneous free thyroxine (free T4) measurement. Patients were excluded from consideration if they had active, concurrent non-thyroidal illness, psychiatric disease, known hypothalamic/pituitary lesions, were under treatment for hyper- or hypothyroidism, were on drugs known to affect TSH levels, or were pregnant. Patients without exclusions were diagnosed with free T3 toxicosis if they had: (1) a markedly subnormal TSH level (less than or equal to 0.1 mU/L), (2) a normal free T4, (3) a normal total T3, (4) evidence of a primary thyroid abnormality (e.g., autonomous function on a thyroid scan), and (5) an elevated free T3 level by tracer equilibrium dialysis. Patients meeting conditions 1-4, but with normal free T3 levels, were considered to have subclinical hyperthyroidism. RESULTS: One thousand twenty-five patients had TSH and simultaneous free T4 determinations, and 148 of these had markedly subnormal TSH but normal free T4 levels. Three patients met the criteria for free T3 toxicosis and three had subclinical hyperthyroidism. All six patients had either multinodular glands or a single nodule on thyroid exam. Four patients were treated with radioactive iodine or surgery, resulting in reversal of the TSH suppression in three cases. CONCLUSION: Apparently healthy ambulatory patients with subnormal TSH levels should be worked up with measurements of free T4 and total T3. If these are normal, a T3 level (by tracer equilibrium dialysis) be obtained to distinguish subclinical hyperthyroidism from overt free T3 toxicosis. A thyroid scan and radioiodine uptake measurement can be obtained to substantiate the diagnosis. Some patients with these conditions will benefit from treatment.

Adult↗

PubMed1994

Implantable venous Doppler microvascular monitoring: laboratory investigation and clinical results.

The purpose of this study was to compare the sensitivity of a 20-mHz ultrasonic Doppler device to detect microvascular thrombosis placed on the vein with that placed on the artery. A feasibility study in animals preceded a comparative clinical study in patients. Six rabbits were used to develop a bilateral hind limb perfusion model. The femoral artery and vein were isolated, and Doppler probes were affixed to each. Clamping of the artery and vein separately was followed by simultaneous measurements in both vascular probes using audio signals and strip-chart recordings. A total of 48 measurements were obtained. Probes placed on the artery immediately detected an arterial occlusion but continued to record pulsation for 220 +/- 40 minutes following venous occlusion. Mean arterial waveform amplitudes diminished by 50 percent of initial values 1 hour following venous occlusion but showed little change thereafter when followed for 6 hours. By contrast, probes placed on the vein detected venous occlusion immediately and arterial occlusion at 6 +/- 2.4 minutes (p < 0.001). Over a 4-year period, 133 patients had free-tissue transfers monitored by implantable 20-mHz ultrasonic Doppler devices: 30 arterial and 103 venous. The arterial monitors detected vascular thromboses in 4 of 6 patients, with 3 flaps salvaged. Venous Doppler monitors detected 16 of 16 thromboses, with 12 flaps salvaged. Six patients had probe/machine malfunctions during their postoperative course and were monitored by clinical means thereafter without thrombosis. There were two late extrusions of the probe cuffs implanted in subcutaneous locations. No adverse effects on the flap vessels were noted in the study. The 20-mHz ultrasonic Doppler device is an effective monitor of blood flow in microvascular anastomoses. When it is placed on the vein, a greater degree of sensitivity is demonstrated, particularly to venous obstruction, compared with probes monitoring arterial flow. The device has been reliable in a variety of institutions and nursing units without need for intensive care monitoring and has resulted in an increased salvage rate for flaps experiencing vascular thrombosis.

Adolescent↗