Mean Recurrence Time Research Articles

Nonparametric Estimation of the Stationary Distribution of a Discrete-Time Semi-Markov Process

In this article, we consider a discrete-time semi-Markov process with finite state space and an observation censored at an arbitrary fixed time. Some intermediate results concerning the empirical estimation of the mean recurrence times of the embedded Markov process and the mean sojourn times of the semi-Markov process are given. We study two nonparametric estimators for the stationary distribution of the semi-Markov process and examine their asymptotic properties, such as strong consistency and asymptotic normality, as the length of the observation tends to infinity. Finally, a numerical application is presented to illustrate the comparison of the two estimators.

Comparing Treatment Options of Pterygium: Limbal Sliding Flap Transplantation, Primary Closing, and Amniotic Membrane Grafting

To compare 3 surgical treatment options of pterygium: limbal sliding flap transplantation, primary closing, and amniotic membrane grafting methods. Seventy-five patients with primary pterygium were included in the study. Snellen visual acuity measurement, grading pterygium, slit-lamp examination, keratometry, and anterior segment photography were performed preoperatively. Twenty-eight eyes of 28 patients (group 1) underwent limbal-conjunctival sliding flap transplantation, 22 eyes of 22 patients (group 2) underwent amniotic membrane grafting, and 25 eyes of 25 patients (group 3) underwent primary closing surgery. The patients were followed up on the first day and the first week after surgery and then at months 1, 3, 6, and 12. The mean size of the pterygium preoperatively was 3.58 ± 1.1 mm in group 1, 3.95 ± 0.90 mm in group 2, and 3.5 ± 0.87 mm in group 3. The mean follow-up time was 15.07 ± 13.8 months in group 1, 20.2 ± 6.7 months in group 2, and 28.04 ± 9.9 months in group 3. Grade 4 corneal recurrence rate in follow-up was 7.1% in group 1, 27.3% in group 2, and 56% in group 3 (p = 0.00). Mean recurrence times were 4.0 ± 1.7, 4.4 ± 3.3, and 4.4 ± 3.6 months according to groups 1, 2, and 3 (p = 0.963). After the surgery, corneal astigmatism decreased and keratometric values increased significantly in all the groups with no statistically significant difference between the groups (p>0.05). Limbal-conjunctival sliding flap transplantation is an efficient method to manage primary pterygium. It may be a safe and effective initial treatment option to reduce risk of recurrence and postoperative complications of pterygium surgery.

Late post-operative recurrent osteosarcoma: Three case reports with a review of the literature

The aim of the present study was to investigate the clinical characteristics and treatment of late recurrent osteosarcoma following surgery. The cases of three patients with late recurrent osteosarcoma, who were treated at the General Hospital of Jinan Military Command, General Hospital of Nanjing Military Command and Xinan Hospital of The Third Military Medical University, were analyzed retrospectively. Furthermore, 10 cases of late recurrent osteosarcoma were retrieved from the literature. In total, eight male and five female cases were selected for the present study. The mean age at recurrence was 25.56 years (range, 13–42 years). The locations of the osteosarcomas were as follows: five cases in the distal femur, two cases in the distal tibia and acetabulum, respectively, and one case in the proximal tibia (the remaining cases were not described). The tumors were histologically classified into three cases of fibroblastic, two cases of traditional-type; two cases of mixed-type and one case each of osteoblastic-, chondroblastic- and telangiectasia-type osteosarcoma (the remaining cases were not described). The mean recurrence time following surgery was 10.02 years (range, 5.2–19.3 years). With regard to the treatment modalities, five patients accepted surgery and chemotherapy, one patient accepted surgery and radiotherapy, two patients accepted surgery alone and one patient did not complete the treatment (the remaining cases were not described). From the 12 cases that were followed-up for between 0.5 and 4.7 years (mean, 2.28 years), one case was lost to follow-up, six patients survived (up to 4.5 years) and six patients succumbed to their condition (0.6–4.7 years). The present study highlights the fact that more focus should be placed upon the long-term follow-up of patients with osteosarcoma. A follow-up is required once every six months, from five years after the diagnosis. The abnormal changes in the surgical site should also receive further attention, in addition to the pulmonary and systemic metastases. Following a diagnosis of late post-operative recurrence, surgery and post-operative chemotherapy are commonly used in clinical treatment, however, the clinical outcome of osteosarcoma requires further observation.

The clinical and imaging features of clear cell meningioma in ten cases

Objective To investigate the clinical features and imaging findings of intracranial clear cell meningioma. Methods The clinical data were reviewed, including presentation, imaging and prognosis of 10 patients suffered from intracranial clear cell meningioma for 2 months-7 years and underwent surgical treatment. The patients included five males and five females with the age from nine to sixty⁃two years old (mean 35.43). The tumors were located at cerebellopontine angle (CPA) zone (n = 5), parietal lobe (n = 1), tuberculum sella (n = 1), jugular foramen (n = 1), tentorium of cerebellum (n = 1) or lateral cerebral ventricle (n = 1). The initial symptoms included headache (n = 4), gait disturbance (n = 2), hearing loss (n = 2), vision loss (n = 1) and bucking (n = 1) which were associated with the mass locations. Results CT (n = 8) and MRI (n = 10) of 10 patients were retrospectively reviewed. CT findings of the lesions presented with hyperdensity (n = 6), isodensity (n = 1), or isodensity with hyperdensity (n = 1). MRI T1WI showed isointensity (n = 4), hypointensity with isointensity (n = 4) or hyperintensity (n = 2), whereas T2WI isointensity with hyperintensity (n = 7), presented hypointensity (n = 1), isointensity (n = 1), or hyperintensity (n = 1). On gadolinium⁃enhanced T1WI, moderate enhancement was seen in 8 lesions and marked enhancement was seen in 2 lesions. In initial CT scanning peritumoral edema was found in 7 cases, dural tail sign in 5 cases, cysts in 7 cases, calcification in 3 cases, periosteal proliferation in 1 case and bone destruction in 5 cases. Seven patients underwent complete resection and 3 underwent subtotal resection. Follow⁃up period was 11-120 months. Recurrence occurred in 5 patients. The mean recurrence time was 55.62 months. Conclusion Clear cell meningioma is a rare meningioma and often occurs in young persons without significant difference in sex. The CPA zone is the most affected area. The prognosis is closely related to the extent of resection. Clear cell meningioma tends to present marked enhancement, peritumoral edema, cystic components, and bone involvement in imaging findings． DOI：10.3969/j.issn.1672⁃6731.2012.05.019

Evaluation of Extensive Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in Patients With Advanced Epithelial Ovarian Cancer

Although standard treatment for advanced epithelial ovarian cancer (EOC) consists of surgical debulking and intravenous platinum- and taxane-based chemotherapy, favorable oncological outcomes have been recently reported with the use of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The aim of the study was to analyze feasibility and results of CRS and HIPEC in patients with advanced EOC. This is an open, prospective phase 2 study including patients with primary or recurrent peritoneal carcinomatosis due to EOC. Thirty-nine patients with a mean (SD) age of 57.3 (9.7) years (range, 34-74 years) were included between September 2005 and December 2009. Thirty patients (77%) had recurrent EOC and 9 (23%) had primary EOC. For HIPEC, cisplatin and paclitaxel were used for 11 patients (28%), cisplatin and doxorubicin for 26 patients (66%), paclitaxel and doxorubicin for 1 patient (3%), and doxorubicin alone for 1 patient (3%). The median intra-abdominal outflow temperature was 41.5°C. The mean peritoneal cancer index (PCI) was 11.1 (range, 1-28); and according to the intraoperative tumor extent, the tumor volume was classified as low (PCI <15) or high (PCI ≥15) in 27 patients (69%) and 12 patients (31%), respectively. Microscopically complete cytoreduction was achieved for 35 patients (90%), macroscopic cytoreduction was achieved for 3 patients (7%), and a gross tumor debulking was performed for 1 patient (3%). Mean hospital stay was 23.8 days. Postoperative complications occurred in 7 patients (18%), and reoperations in 3 patients (8%). There was one postoperative death. Recurrence was seen in 23 patients (59%) with a mean recurrence time of 14.4 months (range, 1-49 months). Hyperthermic intraperitoneal chemotherapy after extensive CRS for advanced EOC is feasible with acceptable morbidity and mortality. Complete cytoreduction may improve survival in highly selected patients. Additional follow-up and further studies are needed to determine the effects of HIPEC on survival.

Cosmetic Results of Wedge Resection of Nail Matrix (Winograd Technique) in the Treatment of Ingrown Toenail

The purpose of this retrospective study is to evaluate the cosmetic results of wedge resection of the nail matrix (Winograd technique) in the treatment of ingrown toenail. This study retrospectively reviewed medical charts of 68 patients with 75 ingrown toenails who underwent surgical correction with the Winograd technique between January, 2008, and December, 2009, at the Orthopaedics and Traumatology Department, Antalya Education and Research Hospital. For the final follow-up, patients were contacted by telephone and completed a telephone questionnaire. Recurrence, cosmetic results, and satisfaction of the patients were the major outcome measures. There was recurrence in 9 patients (13.2%). The mean recurrence time was 6.7 months (range = 2-12 months). All recurrences involved the lateral border of the toenail. Cosmetic ratings were statistically lower in female patients (P = .005). The reasons for poor and acceptable cosmetic results were proximal-incision scar and narrowing of the nail plate. Wedge resection of nail matrix has a considerably high recurrence rate. Furthermore, narrowing of the nail plate is a disadvantage of this procedure. All patients should be informed about the possibility of recurrence and disfigurement in their toenails (narrow nail plate). Particularly, female patients who care about the cosmesis may be dissatisfied with this surgical technique.

Feasibility of Snare Papillectomy in Ampulla of Vater Tumors: Meta-Analysis and Study Results from a Tertiary Referral Center

Ampulla of Vater tumors represent a rare tumor entity and bear a malignant potential. This study at our tertiary referral center aimed at evaluating the feasibility of endoscopic snare papillectomy and long-term endoscopic surveillance in comparison to results of a meta-analysis of comparative trials. Retrospective study in comparison to results of a meta-analysis. Twenty-one patients (mean age 60.2±12.8 years) with ampullary adenoma were included. All patients had undergone ERCP with endoscopic forceps biopsies prior to endoscopic snare papillectomy. Statistical analysis was applied including descriptive analysis of symptoms, therapy and complications. ESP was technically successful in all 21 patients. Histopathology showed 18 adenomas and 3 focal adenocarcinomas which were referred to surgery for modified Whipple's procedure. Follow-up was available in all patients with a mean follow-up of 64 months. Adenoma recurrence occurred in three patients with a mean recurrence time of 25 months (range, 4-66 months). One patient had residual adenoma growth. In the majority of cases ampullary adenomas can be treated endoscopically. Forceps biopsies alone are not reliable enough in detecting malignancy. All patients with ampullary tumor should therefore undergo ESP. Due to the recurrence rate of 16% patients should have close follow-up.

Distinguishing dynamics using recurrence-time statistics

The probability densities of the mean recurrence time, which is the average time needed for a system to recur to a previously visited neighborhood, are investigated in various dynamical regimes and are found to be in agreement with those of the finite-time Lyapunov exponents. The important advantages of the former ones are that they are easy to estimate and that comparable short time series are sufficient. Asymmetric distributions with exponential tails are observed for intermittency and crisis-induced intermittency, while for typical chaos, the distribution has a Gaussian shape. Further, the shape of the distribution distinguishes intermittent strange nonchaotic attractors from those appearing through fractalization and tori collision mechanisms. Furthermore, statistics performed on the peaks in the frequency distribution of recurrence times unveil scaling behavior in agreement with that obtained from the spectral distribution function defined as the number of peaks in the Fourier spectrum greater than a predefined value. The results of the present recurrence statistics are of relevance in classifying different dynamics and providing important insights into the dynamics of a system when only one realization of this system is available. The practical use of this approach for experimental data is shown on experimental electrochemical time series.

Stability and Control of Acyclic Stochastic Processing Networks With Shared Resources

We consider a general model framework for acyclic stochastic processing networks with shared resources that has many applications in telecommunication, computer, and manufacturing systems. A dynamic control policy that utilizes the maximal matching (for scheduling) and the join-the-shortest-queue (for routing) discipline, is shown to maximize the throughput and stabilize the system in a sense called “uniform mean recurrence time property” under fairly mild stochastic assumptions. Owing to the non-Markovian nature of the states, system stability is established using a perturbed Lyapunov function method.

Feasibility of Snare Papillectomy in Ampulla of Vater Tumors: Metaanalysis and Study Results from a Tertiary Referral Center

Purpose: Ampulla of Vater tumors represent a rare tumor entity with malignant potential following the adenoma-carcinoma sequence. Possible diagnostic options include endoscopic transpapillary forceps biopsies (ETP) and endoscopic snare papillectomy (ESP). This study aimed to evaluate the feasability of ESP and long-term endoscopic surveillance at our tertiary referral center in comparison to results of a met-analysis of comparative trials. Methods: 21 patients (mean age 60.2±12.8 years) with ampullary adenoma could be included in the study. All patients had undergone ERCP with ETP prior to ESP. Statistical analysis was applied including descriptive analysis for symptoms, therapy and complications in comparison to results of a met-analysis of comparative trials. Results: ESP was technically successful in all 21 patients. Histopathology of the papillectomy specimen showed 18 adenomas and 3 focal adenocarcinomas which were referred to surgery for modified Whipple procedure. Follow-up (f/u) was available in all patients with mean f/u of 64 months. Adenoma recurrence occurred in three patients with a mean recurrence time of 25 months (range 4 - 66). One patient had residual adenoma growth. Conclusion: In the majority of cases ampullary adenomas can be treated endoscopically. ETP alone is not useful in detecting malignancy (false-negative rate of 15%). All patients with ampullary tumor should therefore undergo ESP. Due to the recurrence rate of 16% patients should have close follow-up.

Epistemic Uncertainty in California-Wide Synthetic Seismicity Simulations

Abstract The generation of seismicity catalogs on synthetic fault networks holds the promise of providing key inputs into probabilistic seismic-hazard analysis, for example, the coefficient of variation, mean recurrence time as a function of magnitude, the probability of fault-to-fault ruptures, and conditional probabilities for foreshock–mainshock triggering. I employ a seismicity simulator that includes the following ingredients: static stress transfer, viscoelastic relaxation of the lower crust and mantle, and vertical stratification of elastic and viscoelastic material properties. A cascade mechanism combined with a simple Coulomb failure criterion is used to determine the initiation, propagation, and termination of synthetic ruptures. It is employed on a 3D fault network provided by Steve Ward (unpublished data, 2009) for the Southern California Earthquake Center (SCEC) Earthquake Simulators Group. This all-California fault network, initially consisting of 8000 patches, each of ∼12 square kilometers in size, has been rediscretized into patches, each of ∼1 square kilometer in size, in order to simulate the evolution of California seismicity and crustal stress at magnitude M ∼5–8. Resulting synthetic seismicity catalogs spanning 30,000 yr and about one-half million events are evaluated with magnitude-frequency and magnitude-area statistics. For a priori choices of fault-slip rates and mean stress drops, I explore the sensitivity of various constructs on input parameters, particularly mantle viscosity. Slip maps obtained for the southern San Andreas fault show that the ability of segment boundaries to inhibit slip across the boundaries (e.g., to prevent multisegment ruptures) is systematically affected by mantle viscosity.

Malignant Brenner tumor of the ovary: analysis of 13 cases

Most Brenner tumors are benign, with only 1% being malignant. In this study we report on 13 cases with malignant Brenner tumor of the ovary and discuss the clinical, demographic and histologic features. Thirteen patients with malignant Brenner tumor of the ovary who were treated at Selçuk University Gynecology Department over a 6-year period from January 2004 to December 2010 were retrospectively analysed from hospital electronic medical records. Clinical and pathologic findings were reported. The median age of the study population was 55.69 ± 11.81 years (range 43-79 years). Most of the patients presented with abdominal pain (6/13, 46.2%). The mean size of the ovarian tumors was 9.19 ± 1.34 cm (range 4-16.5 cm). Six patients (46.2%) were in stage III, five (38.5%) in stage I, and two (15.4%) in stage IV. Ten patients (76.9%) received chemotherapy. The mean follow-up was 38.38 ± 23.25 months (range 5-84 months). During follow-up, recurrence was detected in 7 patients (53.8%). The mean recurrence time was 23.8 ± 14.46 months (range 11-48 months). In our study, we found that diagnosis was at an advanced stage, and recurrence rate was high. The mainstay of treatment is surgical resection, but the exact regimen and benefit of adjuvant therapy remain unknown.

Expression of Adam28 as a prognostic biomarker of survival in patients with early-stage non-small cell lung cancer.

10600 Background: The Adam (a disintegrin and metalloproteinase) family could modulate key cell signaling pathways via the shedding of membrane-associated proteins. Overexpression of Adam28 is involved in cell proliferation and progression in various carcinomas. This study was aimed to evaluate Adam28 expression to serve as prognostic marker in non-small cell lung cancer (NSCLC). Methods: 100 lung cancer tumor tissues and 53 adjacent tissues from patients with stage Ι – IIIa were obtained between 2004 and 2006 in Guangdong Lung Cancer Institute. All of them were pathologically assessed and analyzed with expression profile microarray. Then we conducted the real-time quantitative PCR (qPCR) for validation on the expression level of Adam28 in cancer tissues. Disease free survival was plotted using the Kaplan-Meier method, univariate and multivariate analyses were performed for factors affecting survival of patients. Results: Microarray data demonstrated significantly increased expression of Adam28 in cancer tissues (P<0.001), and confirned by qPCR. Mean value of qPCR was considered as the cut-off point. The expression of Adam28 is significantly correlated with T staging and histology. Patients whose tumors displayed high-level Adam28 showed a significantly shorter mean recurrence time of 39.6 vs 53.4 months (P=0.017). Similarly,N status, clinical stage and performance status (PS) were significant prognostic markers in univariate Cox survival analysis (P-value of 0.1 was adopted as the limit for entering into multivariate survival analysis).Importantly, Adam28 expression (P=0.029) together with N status (P=0.036) and PS (P=0.024) proved to be independent prognostic parameters in multivariate analysis. Conclusions: Our results suggest that Adam28 expression is significantly increased in NSCLC and provides additional prognostic information for survival of surgically treated NSCLC patients. We further hypothesize that high-level expression of Adam28 could relate to an enhanced propensity of tumor cells for survival, proliferation and migration, which calls for further investigation.

Bayesian forecasting of recurrent earthquakes and predictive performance for a small sample size

[1] This paper presents a Bayesian method of probability forecasting for a renewal of earthquakes. When only limited records of characteristic earthquakes on a fault are available, relevant prior distributions for renewal model parameters are essential to computing unbiased, stable time-dependent earthquake probabilities. We also use event slip and geological slip rate data combined with historical earthquake records to improve our forecast model. We apply the Brownian Passage Time (BPT) model and make use of the best fit prior distribution for its coefficient of variation (the shape parameter, alpha) relative to the mean recurrence time because the Earthquake Research Committee (ERC) of Japan uses the BPT model for long-term forecasting. Currently, more than 110 active faults have been evaluated by the ERC, but most include very few paleoseismic events. We objectively select the prior distribution with the Akaike Bayesian Information Criterion using all available recurrence data including the ERC datasets. These data also include mean recurrence times estimated from slip per event divided by long-term slip rate. By comparing the goodness of fit to the historical record and simulated data, we show that the proposed predictor provides more stable performance than plug-in predictors, such as maximum likelihood estimates and the predictor currently adopted by the ERC.

Expression of DNA methyltransferases in liver cancer and its clinical significance

Objective To investigate the expression of DNA methyltransferases (DNMTs) in liver cancer and its clinical significance. Methods The specimens of liver cancer tissues, adjacent tissues, cirrhotic tissues and chronic hepatitis tissues were collected from 50 patients who received radical resection at the First Affiliated Hospital of Sun Yat-Sen University from July 2007 to April 2008. The mRNA and protein expressions of DNMT1,DNMT3a and DNMT3b in liver cancer tissues, adjacent tissues, cirrhotic tissues and chronic hepatitis tissues were detected by real-time quantitative PCR and immunohistochemical staining. The mRNA expression of DNMTs in the liver cancer tissues was compared with those in the adjacent tissues, cirrhotic tissues and chronic hepatitis tissues by using t test and Mann-Whitney U test. The correlation between the protein expression of DNMTs in the liver cancer tissue and the clinicopathological features was analyzed by chi-square test or Fisher exact test, and the tumor-free survival time was analyzed by using Kaplan-Meier method and the difference in tumor-free survival rate between different patients was analyzed by Log-rank test. Results The mRNA expressions of DNMT1, DNMT3a and DNMT3b in the liver cancer tissue were 2.57, 2.29 and 4.86 times higher than those in the adjacent tissues (t = 3.94, 2. 72, 4. 06, P ＜ 0.05 ). The mRNA expressions of DNMT1, DNMT3a and DNMT3b were 2.38,2.14 and 4.66 times higher than those in the cirrhotic tissues, and 6.12, 4.58 and 12.99 times higher than those in the chronic hepatitis tissues. The mRNA expressions of DNMT1, DNMT3a and DNMT3b in the liver cancer tissue were significantly higher than those in the cirrhotic tissues and chronic hepatitis tissues ( U = 587.5,730. 0,562.5; 65.5, 64.5, 71.0, P ＜ 0.05). The protein expression of DNMT1 was correlated with the size, number,TNM stages and vascular invasion of tumors ( x2 = 4.08, 5.95, 4.08, P ＜ 0.05 ). The protein expression of DNMT3a was correlated with the size, number and TNM stages of tumors (x2 = 4.08, 5.95, 4.08, P ＜ 0.05 ).The mean tumor recurrence time of patients with low expressions of DNMT1 and DNMT3a were 9.4 and 8.7 months, which were significantly longer than 5.0 and 3.2 months of those with high expressions of DNMT1 and DNMT3a (x2 =3.89, 9.91, P＜0.05). Conclusions DNMTs play an important role in hepatocarcinogenesis.High expressions of DNMT1 and DNMT3a are correlated with the postoperative recurrence of liver cancer, which are valuable prognostic factors for liver cancer. Key words: Liver neoplasms; DNA methyltransferases; Tumor recurrence

Local recurrences after curettage and cementing in long bone giant cell tumor

BackgroundGiant cell tumor of bone (GCT) is a benign lesion with great propensity for local recurrence. This study aimed to analyse the rates of local recurrence and its possible predisposing factors in Campanacci’s Grade III and II GCT of long bones following intralesional curettage and bone cementing.Materials and Methods:32 cases of either sex with Campanacci’s Grade II (n= 14), and Grade III (n=18) with intact articular surface, operated between 1995 and 2007 in form of intralesional curettage and bone cementing were studied. All the cases were followed up for 2.5-12 years (mean, 6.5), after primary treatment. The mean age at operation was 32.4 years (range, 18.5-40 years). The proximal tibia was involved in 13 cases (40.6%), followed by distal femur (n=11)34.4% distal tibia (n=3) 9.4%, proximal femur (n=2) 3.2% and distal radius (n=3) 9.4%.Results:Eleven patients (34.4%) had local recurrence, of which eight were of Campanacci’s Grade III. The mean recurrence time was 14 months (range, 3-34 months). The two-year recurrence-free survivorship was 71.9% (n=23/32). Post-recurrence mean follow-up was 4.2 years (range, 2-6.5 years).Conclusion:We observed higher rate of local recurrence with Campanacci’s Grade III GCTs. We recommend selective use of this procedure in Grade III lesions, particularly with extensive soft tissue involvement.

On mean recurrence times of Markov chains and spanning tree invariants

We show that the mean recurrence times of (countable state) irreducible and positively recurrent Markov chains are the spanning tree invariants of the first return loop systems. Then, by the Perron–Frobenius theorem, the spanning tree invariants of the first return loop systems of a finite state Markov chain are all equal if and only if the process is doubly stochastic, settling a conjecture on a question in [1] where it was verified for matrices of size at most three.

Crystallized Phenol in Nonoperative Treatment of Previously Operated, Recurrent Pilonidal Disease

Recurrence after surgery for pilonidal disease remains a challenge. We investigated the application of crystallized phenol as a nonoperative treatment for patients with recurrent, previously operated pilonidal disease. Participants were patients treated for recurrent pilonidal disease at our clinics from January 1995 through August 2007. Crystallized phenol was administered on an outpatient basis. Patient and disease characteristics including age, gender, body mass index, occupation, family history, time from previous operation to recurrence and to phenol treatment, number and type of previous operations, and characteristics of recurrent sinuses at entry were prospectively recorded. Outcome variables included number of phenol applications, recovery time, recurrence, and treatment success or failure. A total of 36 patients with recurrent pilonidal disease were treated with crystallized phenol (mean recurrence time after previous surgery, 16.2 +/- 4.6 months; number of previous operations, 1.47 +/- 0.9). The mean number of phenol applications per patient was 3.7 +/- 1.3 (range, 1-7). No serious side effects were observed. Exfoliation of a 2-cm area around the sinus openings in 3 patients (8.3%) was easily treated with ointments locally; patients reported minimal pain. Healing was obtained in all patients in a median of 48 (range, 10-153) days. During follow-up (mean duration, 54.4 +/- 5.2 months; range, 29-169 months), 31 patients (86.1%) had no recurrence and 5 patients (13.9%) had recurrence. Recurrent sinuses were successfully treated by a second course of crystallized phenol in 2 patients, 1 patient refused retreatment, and healing was not obtained with a second treatment course in 2 patients, yielding an overall success rate of 91.7% and failure rate of 8.3%. Crystallized phenol application is a simple, inexpensive nonoperative procedure that can be performed in an outpatient setting and is suitable for the treatment of previously operated recurrent pilonidal disease.

Surgical Excision of Basal Cell Carcinoma with Complete Margin Control: Outcome at 5-Year Follow-Up

Background: The incidence of skin cancer and especially basal cell carcinoma (BCC) has increased in the last few decades. The gold standard of care is usually a surgical excision, but it also has the risk of local recurrence depending on tumor characteristics. Objectives: We analyzed the 5-year cure rates after surgical excision of BCC with complete margin control using paraffin-embedded sections. Methods: A retrospective analysis of 671 patients (45.3% male, 54.7% female) with 777 primary and 85 with recurrent BCC were collected during 2001–2003. All patients underwent surgery with complete margin control using paraffin-embedded sections. When the histological examination revealed a positive margin, another surgical step was performed in the area of residual tumor. Results: Five-year follow-up examinations were possible in 630/862 (73.1%) of patients with BCC. In the group with primary BCC (n = 562), 3 tumor recurrences (0.5%) were identified; in the group with recurrent BCC (n = 68), 2 tumor recurrences (2.9%) were seen, resulting in an overall 5-year recurrence rate of 0.8% for all patients with BCC. The mean tumor recurrence time after surgery was 36.6 months. Conclusion: Local complete tumor resection confirmed by complete margin control using paraffin-embedded sections can achieve excellent cure rates for both primary and recurrent BCC.

Recurrence of Febrile Seizures in Yazd Shahid Sadoughi Hospital

Objective Febrile seizure is the most common problem in pediatric neurology that occurs in 3- 4 % of children. The purpose of this study was to determine febrile seizure recurrence frequency and to evaluate its risk factors. Materials & Methods In a descriptive prospective study, 139 children (6 months to 6 years) with first febrile seizure were admitted to Yazd Shaheed Sadoughi Hospital between March 2004 and August 2005 and were followed up for at least 15 months for febrile seizure recurrence. Results Seventy six boys and 63 girls with a mean age of 2.03 ± 1.21 years were followed up for 25.1±5.5 months. About 30% of them had complex febrile seizures and 37.4% had febrile seizure recurrence with a mean recurrence time of 6.7 ± 5.9 months. About 65% of the children younger than one year and 30% of those older than one year had febrile seizure recurrence. (P value= 0.0001) Recurrence of seizure was seen in 63% of those who had seizure within an hour from the onset of fever and in 33% of those who had seizure after one hour from the onset of fever. (P value = 0.005) Seizures in children younger than one year old and seizures occurring in association with a fever lasting less than an hour were risk factors of febrile seizure recurrence. Conclusion Febrile seizure is more disturbing in children younger than one year old. Antipyretic usage was not effective in preventing seizure recurrence but may reduce discomfort and is reassuring.