Follow-up Interval (follow-up + interval)

Distribution by Scientific Domains
Distribution within Medical Sciences


Selected Abstracts


Endovenous Laser Treatment of the Lesser Saphenous Vein With a 940-nm Diode Laser: Early Results

DERMATOLOGIC SURGERY, Issue 4 2003
Thomas M. Proebstle MD
BACKGROUND Until now, endovenous laser treatment (ELT) of the lesser saphenous vein (LSV) has not been reported. OBJECTIVE To evaluate efficacy and side effects for ELT of the LSV. METHODS Otherwise unselected patients with an incompetent LSV were included. After perivenous infiltration of tumescent local anesthesia, laser energy (940 nm) was administered endovenously, either in a pulsed fashion or continuously during constant backpull of the laser fiber. Patients were scheduled for duplex follow-up at Day 1 and also at 1, 3, 6 and 12 months, postoperatively. RESULTS Forty-one LSVs were targeted in 33 patients with a median age of 66 years (range, 35 to 93). Seventy-three percent of patients had skin changes (C4). Thirty-six percent had an open or healed venous ulcer (C5,6) and 15% a postthrombotic syndrome (ES AS,D PR). Thirty-nine LSVs (95%) completed ELT successfully. During a median follow-up interval of 6 months (range, 3 to 12 months), no recanalization event could be observed. Apart from one thrombosis of the popliteal vein in a patient with polycythemia vera, only minor side effects, particularly no permanent paresthesia, could be observed. CONCLUSION ELT of the LSV under tumescent local anesthesia is feasible and effective. Caution is warranted with ELT of thrombophilic patients. [source]


Wada Memory Performance Predicts Seizure Outcome after Epilepsy Surgery in Children

EPILEPSIA, Issue 7 2003
Gregory P. Lee
Summary: Purpose: Wada memory asymmetries were examined in children from four comprehensive epilepsy surgery centers who subsequently underwent epilepsy surgery to determine whether Wada memory performance could predict degree of seizure relief in children. Methods: One hundred fifty-six children (between ages 5 and 16 years) with intractable epilepsy underwent Wada testing before resective epilepsy surgery (93 within the left hemisphere, and 63 within the right hemisphere). Memory stimuli were presented soon after intracarotid amobarbital injection, and recognition memory for the items was assessed after return to neurologic baseline. Eighty-eight children underwent unilateral temporal lobe resection, and 68 had extratemporal lobe resections. One hundred four (67%) children were seizure free (Engel class I), and 52 (33%) were not seizure free (Engel classes II,IV) at follow-up (mean follow-up interval, 2.3 years). Results: Seizure-free children recalled 19.3% more Wada memory items after ipsilateral injection than did non,seizure-free children (p = 0.008). If analysis was restricted to youngsters with temporal lobectomies (TLs), seizure-free children recalled 27.7% more items after ipsilateral injection than did non,seizure-free TL children (p = 0.004). With regard to individual patient prediction, 75% of children who had memory score asymmetries consistent with the seizure focus were seizure free. In contrast, only 56% of children whose memory score asymmetries were inconsistent with the seizure focus were seizure free (p = 0.01). Conclusions: Results suggest that Wada memory performance asymmetries are related to the degree of seizure relief after epilepsy surgery in children and adolescents. [source]


Transoral carbon dioxide laser microsurgery for recurrent glottic carcinoma after radiotherapy

HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 6 2004
Wolfgang Steiner MD
Abstract Background. Transoral laser microsurgery is successfully performed in the treatment of primary laryngeal carcinomas. Few publications deal with the application in patients with recurrent glottic carcinomas after radiation failure. Our study aims to review our experience with transoral laser microsurgery in these patients. Methods. Thirty-four patients with early and advanced recurrent glottic carcinoma after full-course radiotherapy (rT1, n = 11; rT2, n = 10; rT3, n = 10; rT4, n = 3) had CO2 laser treatment with curative intent between 1987 and 1998. Results. Twenty-four patients (71%) were cured with one or more laser procedures. In nine patients, recurrences could not be controlled by laser microsurgery: six patients underwent total laryngectomy and three palliative treatment. One patient received total laryngectomy because of chondronecrosis after laser treatment. With a median follow-up interval of 38.6 months, the 3-year and 5-year disease-specific survival was 86%. The overall 3-year survival rate was 74%; the corresponding 5-year survival rate was 53%. No major complications occurred. In three cases, temporary tracheostomy was needed. Conclusions. In early-stage and advanced-stage recurrent glottic carcinomas after radiotherapy, CO2 laser treatment can successfully be used as a curative organ-preserving procedure. Compared with salvage laryngectomy, results are superior with respect to preservation of laryngeal function. Great expertise is required, especially in resections of advanced-stage recurrent carcinomas. © 2004 Wiley Periodicals, Inc. Head Neck26: 477,484, 2004 [source]


Mucinous hidradenoma: a report of three cases

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 6 2007
Seng Geok Nicholas Goh
Mucinous cutaneous adnexal tumors are an uncommon occurrence. We describe three cases of mucinous hidradenoma characterized by diffuse and prominent mucinous cell proliferation and discuss the relevant literature. The patients (two men and one woman) ranged in age from 32 to 72 years. The lesions were completely excised, and all patients were alive without evidence of disease (follow-up interval 3,4 years). Case 1 presented as a 1.3-cm eyelid nodule and histology showed a mucinous apocrine hidradenoma with a proliferation of mucinous cells and apocrine glands. Case 2, from the shoulder of a 40-year-old man, was a 2.5-cm well-circumscribed nodule composed of hyperplastic villoglandular proliferation of mucinous cells with focal squamous whorls and focal columnar glandular cells showing decapitation secretion. The tumor was also interpretated as a mucinous hidradenoma, most likely of follicular-apocrine origin. Case 3 was a 3.0-cm scalp nodule. The histology showed a mucinous clear-cell hidradenoma composed of numerous mucinous glands amidst small squamous cells with clear cytoplasm and a hyalinized fibrovascular stroma. [source]


Long-Term Follow-Up Results of Selective Laryngeal Adductor Denervation-Reinnervation Surgery for Adductor Spasmodic Dysphonia

THE LARYNGOSCOPE, Issue 4 2006
Dinesh K. Chhetri MD
Abstract Selective laryngeal adductor denervation-reinnervation surgery for the treatment of adductor spasmodic dysphonia was reported in 1999 in 21 patients with encouraging results. Here, we report long-term results of this procedure. Surgical outcome was evaluated using patient surveys and perceptual voice assessment. Measured outcomes included Voice Handicap Index (VHI)-10 scores, patient questionnaire, and perceptual evaluation for voice breaks and breathiness. Patient survey was obtained from 83 patients, and perceptual voice evaluation was performed in voice samples from 46 patients. Average follow-up interval was 49 months. Mean VHI-10 scores improved from a mean of 35.6 to 12.7. Eighty-three percent showed significantly improved VHI-10 scores, representing improved physical, social, and emotional well-being. There was a high degree of patient satisfaction, with 91% agreeing that their voice is more fluent after the surgery. Perceptual evaluation of postoperative voice samples revealed voice breaks in 26% (15% mild, 4% moderate, 7% severe) and breathiness in 30% (11% mild, 13% moderate, 6% severe). A majority of patients had stable, long-lasting resolution of spasmodic voice breaks. [source]


Longitudinal study of vision and retinal nerve fiber layer thickness in multiple sclerosis

ANNALS OF NEUROLOGY, Issue 6 2010
Lauren S. Talman BA
Objective Cross-sectional studies of optical coherence tomography (OCT) show that retinal nerve fiber layer (RNFL) thickness is reduced in multiple sclerosis (MS) and correlates with visual function. We determined how longitudinal changes in RNFL thickness relate to visual loss. We also examined patterns of RNFL thinning over time in MS eyes with and without a prior history of acute optic neuritis (ON). Methods Patients underwent OCT measurement of RNFL thickness at baseline and at 6-month intervals during a mean follow-up of 18 months at 3 centers. Low-contrast letter acuity (2.5%, 1.25% contrast) and visual acuity (VA) were assessed. Results Among 299 patients (593 eyes) with ,6 months follow-up, eyes with visual loss showed greater RNFL thinning compared to eyes with stable vision (low-contrast acuity, 2.5%: p < 0.001; VA: p = 0.005). RNFL thinning increased over time, with average losses of 2.9,m at 2 to 3 years and 6.1,m at 3 to 4.5 years (p < 0.001 vs 0.5,1-year follow-up interval). These patterns were observed for eyes with or without prior history of ON. Proportions of eyes with RNFL loss greater than test-retest variability (,6.6,m) increased from 11% at 0 to 1 year to 44% at 3 to 4.5 years (p < 0.001). Interpretation Progressive RNFL thinning occurs as a function of time in some patients with MS, even in the absence of ON, and is associated with clinically significant visual loss. These findings are consistent with subclinical axonal loss in the anterior visual pathway in MS, and support the use of OCT and low-contrast acuity as methods to evaluate the effectiveness of putative neuroprotection protocols. ANN NEUROL 2010;67:749,760 [source]


20-year prospective follow-up study of specialized treatment for adolescents who offended sexually,

BEHAVIORAL SCIENCES & THE LAW, Issue 1 2010
C.Psych., James R. Worling Ph.D.
Most follow-up investigations of the effectiveness of specialized treatment for adolescents who have offended sexually have not included a comparison group. Furthermore, the average length of most previous studies is approximately 5 years. This investigation is a 10-year extension of our prospective, 10-year follow-up study of specialized treatment (Worling & Curwen, 2000). Recidivism data (criminal charges) were collected from a national database for 148 adolescents who had offended sexually. Adolescents were between 12 and 19 years of age (M,=,15.5; SD,=,1.5) at assessment, and the follow-up interval spanned from 12 to 20 years (M,=,16.23; SD,=,2.02). Relative to the comparison group (n,=,90), adolescents who participated in specialized treatment (n,=,58) were significantly less likely to receive subsequent charges for sexual, nonsexual violent, and nonviolent crimes. These data add to the growing body of research supporting the effectiveness of specialized treatment for individuals who have offended sexually. Copyright © 2009 John Wiley & Sons, Ltd. [source]


Managing varicoceles in children: results with microsurgical varicocelectomy

BJU INTERNATIONAL, Issue 3 2005
Jonathan Schiff
Authors from New York present their experience of elective varicocelectomy, using microsurgical techniques, in a large series of children. They found the procedure to be safe and effective, and gave a much lower complication rate than the published rate in open varicocelectomy. The results of urethroplasty in post-traumatic paediatric urethral strictures are presented by authors from Mansoura. They found the overall success of one-stage perineal anastomotic repair of such strictures to be excellent, with very little morbidity. OBJECTIVE To report our experience of microsurgical subinguinal varicocelectomy in boys aged ,,18 years. PATIENTS AND METHODS Boys aged ,,18 years treated with microsurgical varicocelectomy between 1996 and 2000 at one institution were retrospectively reviewed. Indications for surgery included ipsilateral testicular atrophy, large varicocele or pain. Microsurgery was assisted by an operating microscope (×10,25) allowing preservation of the lymphatics, and the testicular and cremasteric arteries. Patient age, varicocele grade, complications and follow-up interval were recorded. RESULTS In all there were 97 microsurgical subinguinal varicocelectomies (23 bilateral) in 74 boys (mean age 14.7 years). Left-sided varicoceles were significantly larger (mean grade 2.9) than right-sided (mean grade 1.4) varicoceles. The mean follow-up was 9.6 months. There were four complications: two hydroceles, of which one resolved spontaneously after 4 months; one patient had persistent orchialgia that resolved after 8 months; and one developed hypertrophic scarring at the inguinal incision site. There were no infections, haematomas or intraoperative injuries to the vas deferens or testicular arteries. All boys were discharged home on the day of surgery. CONCLUSIONS Microsurgical subinguinal varicocelectomy in boys is a safe, minimally invasive and effective means of treating varicoceles. Compared with published results of the retroperitoneal mass ligation technique, which has a 15% overall complication rate and a 7,9% hydrocele occurrence rate, the microsurgical subinguinal approach appears to offer less morbidity, with a 1% hydrocele rate. We consider that microsurgical subinguinal varicocelectomy offers the best results with lower morbidity than other techniques. [source]


Fifteen-year follow-up of a randomized clinical trial of ultrasonographic screening for abdominal aortic aneurysms

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 6 2007
H. A. Ashton
Background: Long-term benefits of screening for abdominal aortic aneurysm (AAA) are uncertain. These are the final results of a randomized controlled screening trial for AAA in men, updating those reported previously. Benefit and compliance over a median 15-year interval were examined. Methods: One group of men were invited for ultrasonographic AAA screening, and another group, who received standard care, acted as controls. A total of 6040 men aged 65,80 years were randomized to one of the two groups. Outcome was monitored in terms of AAA-related events (surgery or death). Results: In the group invited for screening, AAA-related mortality was reduced by 11 per cent (from 1·8 to 1·6 per cent, hazard ratio 0·89) over the follow-up interval. Screening detected an AAA in 170 patients; 17 of these died from an AAA-related cause, seven of which might have been preventable. The incidence of AAA rupture after an initially normal scan increased after 10 years of follow-up, but was still low overall (0·56 per 1000 person-years). Conclusion: Screening with a single ultrasonography scan still conferred a benefit at 15 years, although the results were not significant for this population size. Fewer than half of the AAA-related deaths in those screened positive could be prevented. Registration number: ISRCTN 00079388 (http://www.controlled-trials.com). Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source]


Critical reappraisal of current surveillance strategies for Barrett's esophagus: analysis of a large German Barrett's database

DISEASES OF THE ESOPHAGUS, Issue 8 2008
B. H. A. Von Rahden
SUMMARY Endoscopic surveillance is recommended for patients with Barrett's esophagus (BE). Based on a large database, gathered from predominantly community-based practices in Germany, we aimed to investigate the time-course of malignant progression and apply these findings to current clinical practice. Data of 1438 patients with BE from a large German BE database were analyzed. Patients with at least one follow-up endoscopy/biopsy were included. Detection of ,malignant Barrett' (either high-grade intra-epithelial neoplasia or invasive adenocarcinoma) was considered as study end-point. Of 1438 patients with BE, 57 patients had low-grade intra-epithelial neoplasia (LG-IN) on initial biopsy and 1381 exhibited non-neoplastic BE. ,Malignant Barrett' was detected in 28 cases (1.9%) during a median follow-up period of 24 months (1,255), accounting for an incidence of 0.95% per patient year of follow-up. The frequency of ,malignant Barrett' was significantly higher (P < 0.001, ,2 -test) in the LG-IN group (n = 11, 19.3%) compared with the non-neoplastic BE group (n = 17, 1.2%). In the non-neoplastic BE group, ,malignant Barrett' was predominantly found during re-endoscopy within the first year of follow-up (12 of 17; 70.6%), in contrast to the LG-IN group, in which ,malignant Barrett' was observed predominantly after a time exceeding 12 months (8 of 11, 72.7%; P = 0.05, Fisher's exact test). Initial endoscopic evaluations seem to play the most crucial role in managing BE. After 1 year of follow-up, endoscopic surveillance should be focused on patients with LG-IN. In patients with repeatedly proven non-neoplastic BE, elongation of the follow-up intervals to the upper limit of current guidelines, that is, 5 years, might be justified. [source]


Endovascular stent implantation for treatment of peripheral artery disease

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 3 2007
M. Schillinger
Endovascular stent implantation is a rapidly emerging technology for treatment of arterial obstructions in the entire circulation. During recent years, several randomized studies evaluated the effects of stenting in lower limb arteries. We herein provide an overview on data of trials in the iliac and femoropopliteal vessel area discussing the benefits and limitations of endovascular stents. In the iliac arteries, midterm and long-term data from one randomized trial including analysis on patency, clinical outcomes, cost-effectiveness and quality of life indicate that balloon angioplasty with selective stenting remains the therapy of choice for endovascular revascularization. In the femoropopliteal arteries, balloon-expanding stents were not superior to balloon angioplasty for treatment of short lesions, and self-expanding nitinol stents also failed to show a beneficial effect in short lesions below 5 cm. However, including longer lesions, one randomized trial indicated a beneficial effect of nitinol stents in lesions with a median length around 10,12 cm. Further studies and longer follow-up intervals are needed to confirm these data. Meanwhile, balloon angioplasty with optional stenting also remains the recommended endovascular approach for the femoropopliteal segment. [source]


Personality pathology and substance abuse in eating disorders: A longitudinal study

INTERNATIONAL JOURNAL OF EATING DISORDERS, Issue 3 2008
Heather Thompson-Brenner PhD
Abstract Objective: Substance abuse has been shown to predict poor outcome in eating disorder (ED) samples, and prior cross-sectional data on personality subtypes of EDs suggest that substance abuse is associated with dysregulated and possibly avoidant-insecure subtypes. This study investigates longitudinal associations between personality and substance use. Method: Personality pathology and substance use were assessed in 213 individuals with anorexia nervosa and bulimia nervosa at baseline; substance use was assessed at regular follow-up intervals over a 9-year period. Results: Of the five personality factors identified, the obsessional-sensitive and high-functioning types were negatively associated with substance abuse at baseline, while the behaviorally dysregulated type was positively associated with substance abuse at baseline. Longitudinal associations were observed, suggesting that obsessional-sensitive personality type was protective against the development of substance abuse. Longitudinal associations between the other personality types and substance abuse were nonsignificant after baseline substance abuse history was included as a covariate in the model. Conclusion: Substance use demonstrates cross-sectional associations with personality style, but substance abuse history appears to be the most important predictor of future substance abuse in women with eating disorders. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2008 [source]


A longitudinal study of mental health consumer/survivor initiatives: Part 3,A qualitative study of impacts of participation on new members

JOURNAL OF COMMUNITY PSYCHOLOGY, Issue 3 2006
Joanna Ochocka
This article examines the outcomes of participation in mental health Consumer/Survivor Initiatives (CSIs) and identifies helpful qualities of CSIs through a longitudinal, qualitative study that involved in-depth interviews of people who experienced severe mental health challenges in Ontario, Canada. We used a nonequivalent control group design in which we compared active participants in CSIs ( n = 15) with nonactive participants ( n = 12) at baseline and at 9- and 18-month follow-up intervals. Compared with non-CSI participants, CSI participants reported more stable mental health, enhanced social support, sustained work, stable income, and participation in education and training at 9- and 18-month interviews. The helpful qualities of CSIs that participants reported were (1) safe environments that provide a positive, welcoming place to go; (2) social arenas that provide opportunities to meet and talk with peers; (3) an alternative worldview that provides opportunities for members to participate and contribute; and (4) effective facilitators of community integration that provide opportunities to connect members to the community at large. The findings are discussed in terms of previous research in self-help and consumer-run organizations in mental health. © 2006 Wiley Periodicals, Inc. [source]


Treatment of Pain in Dercum's Disease with Lidoderm® (Lidocaine 5% Patch): A Case Report

PAIN MEDICINE, Issue 8 2008
Mehul J. Desai MD
ABSTRACT Introduction., Dercum's disease is a rare disorder characterized by multiple painful subcutaneous lipomas on the trunk and extremities. It most commonly occurs in obese, postmenopausal women. The pain associated with this condition is postulated to arise from enlarging lipomas producing pressure on peripheral nerves, thereby initiating pain and sometimes paresthesias. Treatment has been challenging due to the rarity of this condition. Case., A patient with Dercum's disease successfully treated with transdermal lidocaine 5% patches. The patient's pain was initially rated as an 8/10. At follow-up examination after 1 month, the patient rated her pain as 3/10,a >60% reduction in pain; this pain reduction persisted at subsequent 1-month follow-up intervals. Conclusion., Current therapeutic options in the treatment of Dercum's disease have proven either ineffective or cumbersome. The use of transdermal lidocaine is a safe and non-invasive treatment modality that has been efficacious in alternate forms. The use of this medication might prove preferable to more invasive or risky treatment and warrants further investigation. [source]


Vestibular Effects of Cochlear Implantation,

THE LARYNGOSCOPE, Issue S103 2004
Craig A. Buchman MD
Abstract Objectives/Hypothesis: Cochlear implantation (CI) carries with it the potential risk for vestibular system insult or stimulation with resultant dysfunction. As candidate profiles continue to evolve and with the recent development of bilateral CI, understanding the significance of this risk takes on an increasing importance. Study Design: Between 1997 to 2001, a prospective observational study was carried out in a tertiary care medical center to assess the effects of unilateral CI on the vestibular system. Methods: Assessment was performed using the dizziness handicap inventory (DHI), vestibulo-ocular reflex (VOR) testing using both alternate bithermal caloric irrigations (ENG) and rotational chair-generated sinusoidal harmonic accelerations (SHA), and computerized dynamic platform posturography (CDP) at preoperative, 1-month, 4-month, 1-year and 2-year postimplantation visits. CI was carried out without respect to the preoperative vestibular function test results. Results: Specifically, 86 patients were entered into the study after informed consent. For the group as a whole, pair wise comparisons revealed few significant differences between preoperative and postoperative values for VOR testing (ENG and SHA) at any of the follow-up intervals. Likewise, DHI testing was also unchanged except for significant reductions (improvements) in the emotional subcategory scores at both the 4-month and 1-year intervals. CDP results demonstrated substantial improvements in postural sway in the vestibular conditions (5 and 6) as well as composite scores with the device "off" and "on" at the 1-month, 4-month, 1-year, and 2-year intervals. Device activation appeared to improve postural stability in some conditions. Excluding those patients with preoperative areflexic or hyporeflexic responses in the implanted ear (total [warm + cool] caloric response , 15 deg/s), substantial reductions (,21 deg/s maximum slow phase velocity) in total caloric response were observed for 8 (29%) patients at the 4-month interval. These persisted throughout the study period. These changes were accompanied by significant low frequency phase changes on SHA testing confirming a VOR insult. Of interest, no significant changes were detected in the DHI or CDP, and there were no effects of age, sex, device manufacturer, or etiology of hearing loss (HL) for these patients. Conclusions: Unilateral CI rarely results in significant adverse effects on the vestibular system as measured by the DHI, ENG, SHA, and CDP. On the contrary, patients that underwent CI experienced significant improvements in the objective measures of postural stability as measured by CDP. Device activation in music appeared to have an additional positive effect on postural stability during CDP testing. Although VOR testing demonstrated some decreases in response, patients did not suffer from disabling vestibular effects following CI. The mechanism underlying these findings remains speculative. These findings should be considered in counseling patients about CI. [source]


Randomized clinical trial of laparoscopic versus open fundoplication for gastro-oesophageal reflux disease,

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 8 2004
R. Ackroyd
Background: The aim of this study was to compare laparoscopic and open Nissen fundoplication for gastro-oesophageal reflux disease in a randomized clinical trial. Methods: Ninety-nine patients were randomized to either laparoscopic (52) or open (47) Nissen fundoplication. Patients with oesophageal dysmotility, those requiring a concurrent abdominal procedure and those who had undergone previous antireflux surgery were excluded. Independent assessment of dysphagia, heartburn and patients' satisfaction 1, 3, 6 and 12 months after surgery was performed using multiple standardized clinical grading systems. Objective measurement of oesophageal acid exposure and lower oesophageal sphincter pressure before and after surgery, and endoscopic assessment of postoperative anatomy, were performed. Results: Operating time was longer in the laparoscopic group (median 82 versus 46 min). Postoperative pain, analgesic requirement, time to solid food intake, hospital stay and recovery time were reduced in the laparoscopic group. Perioperative outcomes, postoperative dysphagia, relief of heartburn and overall satisfaction were equally good at all follow-up intervals. Reduction in oesophageal acid exposure, increase in lower oesophageal sphincter tone and improvement in endoscopic appearances were the same for the two groups. Conclusion: The laparoscopic approach to Nissen fundoplication improved early postoperative recovery, with an equally good outcome up to 12 months. Copyright © 2004 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source]


Validation of the postoperative nomogram for 12-year sarcoma-specific mortality

CANCER, Issue 10 2004
Fritz C. Eilber M.D.
Abstract BACKGROUND On the basis of a prospectively followed cohort of adult patients with primary soft tissue sarcoma (STS) who were treated at Memorial Sloan-Kettering Cancer Center (MSKCC; New York, NY), a nomogram for predicting sarcoma-specific mortality was developed. Although this nomogram was found to be accurate by internal validation tests, it had not been validated in an external patient cohort, and thus its universal applicability remained unproven. METHODS Between 1975 and 2002, 1167 adult patients (age , 16 years) underwent treatment for primary STS at the University of California,Los Angeles (UCLA; Los Angeles, CA). All patients treated with an ifosfamide-based chemotherapy protocol (n = 238) were excluded from the current analysis. The remaining 929 patients constituted the population on which the validation study was performed. The nomogram validation process comprised two activities. First, the extent of discrimination was quantified using the concordance index. Second, the level of calibration was assessed by grouping patients with respect to their nomogram-predicted mortality probabilities and then comparing group means with observed Kaplan,Meier estimates of disease-specific survival. RESULTS With median follow-up intervals of 48 months for all patients and 60 months for surviving patients, the 5-year and 10-year disease-specific survival rates were 77% (95% confidence interval [CI], 74,80%) and 71% (95% CI, 67,75%), respectively. Application of the nomogram to the UCLA data set yielded a concordance index of 0.76, and the observed correspondence between predicted and actual outcomes suggested a high level of calibration. CONCLUSIONS In the current study, the MSKCC Sarcoma Nomogram was found to provide accurate survival predictions when it was applied to an external cohort of patients who were treated at UCLA. Cancer 2004. © 2004 American Cancer Society. [source]


Model simulation of the patient flow through a screening centre for diabetic retinopathy

ACTA OPHTHALMOLOGICA, Issue 6 2005
Anja B. Hansen
Abstract. Purpose:,To construct a quantitative, flexible and simplified mathematical model of the patient flow through the Eye Clinic at the Steno Diabetes Centre (SDC) in order to enable rational dimensioning and assess the effects of modifications. Methods:,Patient data were drawn from the Eye Care database at the SDC. A simple patient flow model was constructed, allowing simultaneous adjustments of all variables, and the model was tested. Two scenarios were simulated: (1) adjusting the algorithm that assigns the follow-up intervals, and (2) increasing the population size to include all patients with diabetes in Copenhagen County. Results:,The model can describe the patient flow under steady state conditions, but is less precise in predicting transient changes with the present set-up. Accordingly all simulations were run for a substantial number of iterations. The two scenarios illustrate the usefulness of the model by calculating the required photographic examination capacity for the specific population, thereby allowing better estimations of future dimensioning of the organization. Conclusion:,The study presents a patient flow model that can be used to illustrate the effects of proposed changes prior to their implementation, specifically with respect to the capacity of the system. [source]