Rectus Sheath Block Improves Patient Recovery Following Open Aortic Surgery.

BACKGROUND: Postoperative pain management remains a barrier to recovery following aortic surgery. Although epidural catheters help in adjunctive pain management, less is known about the use of rectus sheath blocks. We compared patient recovery following open abdominal aortic surgery (OAS) with and without adjunctive rectus block. METHODS: Adult patients undergoing open abdominal aortic aneurysm repair and aortobifemoral or aortoiliac bypass for occlusive disease were identified and stratified by use of general anesthesia alone (GA) versus adjunctive use of a rectus sheath block (GA + RB). A small number of patients with GA and concomitant epidural analgesia, along with patients that had retroperitoneal repairs, were not included in further analysis. Outcomes included time to extubation, intraoperative and postoperative morphine milligram equivalents (MME) utilization, length of stay, discharge MME, and postoperative complications. Categorial data were compared with Person Chi-Square tests or Fisher's exact tests. Continuous data were tested with independent t-tests or Mann-Whitney U-tests. RESULTS: From January 2017 to April 2022, there were 106 patients who underwent open aortic surgery, 55 patients with GA alone, 39 with GA + RB, and 12 patients who had a GA with concomitant epidural analgesia. Between GA and GA + RB, patients were comparable in both groups in terms of age, BMI (body mass index), smoking history, hypertension, diabetes, CAD (coronary artery disease), COPD (chronic obstructive pulmonary disease), and ASA (American Society of Anesthesiologists) class and prior opioid use. Patients with GA + RB were more likely to have scheduled elective procedures (80% GA cohort vs. 94.9% RB, P = 0.040), and a lower incidence of retroperitoneal exposure (14.5% GA cohort vs. 0% RB, P = 0.019). Patients with GA + RB had shorter time to extubation than GA (84.6% < 12 hr vs. 44.4%, P < 0.001), greater rate of procedural ketamine usage (GA + RB: 61.5% vs. GA: 40.0%, P = 0.049), lower MME at first postoperative day (median MME GA + RB: 25.0 vs. GA: 67.5, P = 0.002), lower discharge MME (median MME GA + RB: 142.5 vs. GA: 225.0, P = 0.036), and overall shorter length of stay (median stay GA + RB: 5 vs. GA: 6 days, P = 0.006). Postoperative complications were similar between groups. Similar findings were found in the comparison between elective-only GA and GA + RB patients and after exclusion of patients who only had a single shot of regional anesthesia. CONCLUSIONS: Patients that receive adjunctive rectus sheath blocks for pain control following OAS utilize fewer opioid medications during hospital stay and at discharge. Rectus sheath blocks represent an alternative option to other periprocedural analgesia following open aortic surgery.

Study of Association of Various Psychiatric Disorders in Brain Tumors.

Background Brain tumors may be associated with high morbidity, and psychiatric symptoms may be an early manifestation. It is important to address mental symptoms as early as possible because they are prone to develop psychiatric comorbidities in future. If untreated, these situations may worsen and lead to burden upon caregivers. Methods A total of 176 brain tumor patients between January 2021 and January 2022 constituted the sample size. All recently diagnosed cases of brain tumor with age equal to or more than 18 years who can comprehend and answer questionnaires were included. Patients with a long history of brain tumor or who had a history of a psychiatric illness other than presenting symptoms or any other serious medical illness were excluded. Results Twenty-seven percent of brain tumor patients had psychiatric symptoms. Depressive symptoms were the most common, associated with 24% of patients, followed by anxiety disorders. Psychiatric disorders were more common in supratentorial compared to infratentorial tumors. Psychiatric symptoms seem to be associated more commonly with malignant tumors and peritumoral edema. Among malignant tumors, depressive symptoms tend to be related with high-grade glioma, and among benign tumors, they were more common in meningioma. No predilection to laterality and anatomical lobe involvement is reported. Conclusion Screening of psychiatric disorders should be a routine in brain tumor patients. An integrated approach is required to treat brain tumor patients. Healthcare professionals should be more vigilant about the onset of psychiatric symptoms and the need of palliative care to improve the quality of life.

Female Sex is Associated with Worse Outcomes following Complex Fenestrated or Branched Endovascular Aortic Repair.

BACKGROUND: Sex-related discrepancies after standard endovascular aneurysm repair (EVAR) are noted to disproportionally affect females. A growing body of literature suggests similar disparities may extend to complex fenestrated or branched endovascular aneurysm repair (FBEVAR). However, recent examination of complex FBEVAR by a consortium of high-volume centers noted equivalent mortality among sexes. Whether similar results extend to non-trial data is unknown. METHODS: We examined all juxta-renal through type IV thoraco-abdominal aneurysms (sealing zones 6-8) which underwent elective FBEVAR within the Vascular Quality Initiative (VQI) database from January 2012 to December 2020. Urgent, symptomatic, ruptured, and staged cases were excluded, as were parallel stent grafts. Demographics, comorbid conditions, and technical factors were compared between sexes. Univariate analysis with Wilcoxon ranked sum tests and Chi-square tests of proportion were performed, followed by multivariate logistic regression for failure of target vessel technical success, reintervention, complications, and in-hospital mortality. RESULTS: Our analysis included 1,521 patients, 1,180 males (77.6%) and 341 females (22.4%). There were noted differences in pre-operative demographics, medical optimization, and technical aspects of the procedure. However, no difference was noted in proximal or distal sealing stents, number of fenestrations, or immediate endoleaks. On a multi variate logistic regression, female sex was an independent predictor of failure of target vessel technical success (odds ratio (OR) 3.339, 95% confidence interval (CI): 2.173-5.132, P < 0.001), reintervention (OR 2.192, 95% CI: 1.304-3.683, P = 0.003), complications (OR 1.747, 95% CI: 1.282-2.381, P < 0.001), and in-hospital mortality (OR 2.836, 95% CI: 1.510-5.328, P = 0.001). CONCLUSIONS: Females suffer worse outcomes after FBEVAR despite similar extent of disease, number of fenestrations, and incidence of immediate endoleak. Notable discrepancies were higher rates of chronic obstructive pulmonary disease (COPD) and lower rates of pre-operative aspirin, statin, and beta blocker therapy in females. Controlling for pre-operative demographics, female sex remained an independent predictor of worse outcomes. These discrepancies warrant further examination and should impact case planning for female patients undergoing complex aortic aneurysm repair.

Intraoperative electroencephalographic changes during transcarotid artery revascularization are more frequent than previously reported.

OBJECTIVE: Up to 14% of patients undergoing carotid endarterectomy with continuous electroencephalographic (EEG) neuromonitoring will require shunt placement because of EEG changes. However, the initial studies of transcarotid artery revascularization (TCAR) found only one patient with temporary EEG changes. We report our experience with intraoperative EEG monitoring during TCAR. METHODS: We conducted a retrospective review of patients who underwent TCAR at two urban hospitals within an integrated healthcare network from May 2017 to January 2020. The data included demographic information, patient comorbidities, symptom status, previous carotid interventions, anatomic details, contralateral disease, intraoperative vital signs and EEG changes, and postoperative major adverse events (transient ischemic attack, stroke, myocardial infarction [MI], and death) both initially and at 30 days postoperatively. The Fisher exact test was used for categorical data and the Wilcoxon rank sum test for continuous data. RESULTS: A total of 89 patients underwent TCAR during the study period, of whom 71 (79.8%) received intraoperative EEG neuromonitoring. Of the 89 patients, 70.8% were men and 29.2% were women. The median age was 75 years (IQR, 68-82.5 years). Symptomatic patients accounted for 41.6% of the cohort. Of the 71 patients who received continuous neuromonitoring, 9 experienced EEG changes during TCAR (12.7%). The changes resolved in seven patients with pressure augmentation in three and switching to a low flow toggle in three. One patient who had sustained EEG changes had a new postoperative neurologic deficit. The median carotid stenosis percentage on preoperative computed tomography angiography was lower for patients with EEG changes than for those without (67% vs 80%; P = .01). No correlation was found between symptom status or 30-day stroke in patients with and without EEG changes (P = .49 and P = .24, respectively). Overall, three postoperative strokes, two postoperative deaths, and one MI occurred, for a composite 30-day stroke, death, and MI rate of 6.7%. CONCLUSIONS: Changes in continuous EEG monitoring were more frequent in our study than previously reported. Less severe carotid stenosis might be associated with a greater incidence of EEG changes. Limited data are available on the prognostic ability of EEG to detect clinically relevant changes during TCAR, and further studies are warranted.

High-power solid-state amplifier for superconducting radio frequency cavity test facility.

A horizontal test facility is set up at the Raja Ramanna Centre for Advanced Technology to test the superconducting radio frequency dressed cavities. Along with the cryomodule, control instrumentation, and the power coupler, this facility incorporates a high-power solid-state amplifier for establishing the desired cavity voltage gradient during the testing. This article describes the design, construction, rigorous testing, and measured results of this high-power solid-state radio frequency amplifier and its constituent components. Its maximum output power is 36 kW (average) at the operating frequency of 650 MHz. Its main features are its modular and scalable design with in-house developed constituent components. These components include 500 W, 20 dB gain modules, novel two-tier radial dividers, combiners, power sensors, and aperture-coupled directional couplers. Their excellent reprise performance for the multiple quantities confirms the design methodology presented here. The measured wall plug efficiency of this 36 kW amplifier is 43.6%, and its power gain is 86 dB. The designed radial combiner is highly efficient (power-combining efficiency of 98.4%), and the directional coupler exhibits a very low loss (insertion loss of 0.05 dB).

Study of internet addiction and its association with depression and insomnia in university students.

INTRODUCTION: Use of internet has increased exponentially worldwide with prevalence of internet addiction ranging from 1.6% to 18 % or even higher. Depression and insomnia has been linked with internet addiction and overuse in several studies. AIMS AND OBJECTIVES: Present study has looked in to pattern and prevalence of internet addiction in university students. This study has also explored the association of internet addiction with depression and insomnia. MATERIAL AND METHODS: In this cross sectional study 954 subjects were enrolled who had been using internet for past 6 months. Information regarding pattern of use and socio demographic characteristics were recorded. Internet addiction Test (IAT), PHQ-9,and insomnia Severity Index (ISI) were applied to measure internet addiction, depression and insomnia respectively. RESULTS: Among 954 subjects, 518 (60.59%) were male and 376 (39.41%) were female with mean age of 23.81 (SD ± 3.72). 15.51% study subjects were internet addicts and 49.19% were over users. Several parameters including graduation level, time spent per day on line, place of internet use, smoking and alcohol had significant association with internet addiction. Internet addiction was predominantly associated with depression and insomnia. CONCLUSION: Internet addiction is a rising concern among youth. Several parameters including gender, time spent on line, alcohol, smoking predicts higher risk of internet addiction. Depression and insomnia are more common in internet addicts and overusers.

Outcomes of target vessel endoleaks after fenestrated-branched endovascular aortic repair.

OBJECTIVE: The objective of this study was to determine the incidence rate, outcomes, and risk factors of target vessel-related endoleaks after fenestrated-branched endovascular aortic repair (F-BEVAR) for pararenal aneurysms or thoracoabdominal aortic aneurysms (TAAAs). METHODS: We reviewed consecutive patients treated by F-BEVAR between 2007 and 2017. Target vessel endoleaks were identified by computed tomography angiography (CTA). Follow-up included CTA and duplex ultrasound before discharge, at 2 months, at 6 months, and annually thereafter. Primary endoleaks were detected by predismissal CTA; secondary endoleaks were absent on the first CTA and were identified during follow-up. End points were spontaneous resolution of primary endoleaks, secondary interventions, and aneurysm rupture. Multivariable analyses were performed for risk factors of target vessel endoleaks and predictors of spontaneous resolution. RESULTS: A total of 382 patients (mean age, 75 ± 8 years; 75% male) underwent F-BEVAR for 195 pararenal aneurysms and 187 TAAAs with 1204 renal-mesenteric arteries targeted by 981 fenestrations and 223 directional branches. Fifty-two target vessel endoleaks were identified in 41 patients; 41 were type IIIC (interattachment), 10 were type IC (distal bridging stent sealing zone), and 1 was type IIIB (bridging stent fabric tear). Thirty-three patients (9%) had primary target vessel endoleaks in 41 target vessels (3%). Eight patients (2%) developed 11 secondary target vessel endoleaks. Directional branches were more prone to primary endoleaks (13/223 [6%]) in comparison to fenestrations (28/981 [3%]; P = .03). However, branch endoleaks resolved more often spontaneously (11/14 [79%]) compared with fenestration endoleaks (14/38 [37%]; P = .008). Other risk factors for target vessel endoleaks included inner aortic diameter ≥30 mm at the target vessel origin, four or more targeted vessels, TAAA (for primary endoleaks), and physician-modified endograft (for secondary endoleaks). Four patients with primary endoleaks underwent successful reintervention before discharge, and 29 were observed with a mean follow-up of 24 ± 21 months. Of the 41 primary endoleaks, 25 resolved spontaneously in 20 patients (61%) at first follow-up with no recurrences. Of the observed endoleaks, 11 persisted in 9 patients, and 8 of those endoleaks were treated in 7 patients. All secondary target vessel endoleaks required reintervention. There was one possible aneurysm rupture attributed to persistent secondary target vessel endoleak. CONCLUSIONS: Target vessel endoleak on CTA at discharge occurs in 1 of 10 patients treated by F-BEVAR. Of these, two-thirds resolve spontaneously, especially those affecting directional branches. Among patients with a persistent endoleak, endovascular reintervention is usually successful and aneurysm rupture is rare.

System efficiency analysis for high power solid state radio frequency transmitter.

This paper examines some important relationships, related with the system efficiency, for very high power, radio frequency solid-state transmitter; incorporating multiple solid-state power amplifier modules, power combiners, dividers, couplers, and control/interlock hardware. In particular, the characterization of such transmitters, at the component as well as the system level, is discussed. The analysis for studying the influence of the amplitude and phase imbalance, on useful performance parameters like system efficiency and power distribution is performed. This analysis is based on a scattering parameter model. This model serves as a template for fine-tuning the results, with the help of a system level simulator. For experimental study, this approach is applied to a recently designed modular and scalable solid-state transmitter, operating at the centre frequency of 505.8 MHz and capable of delivering a continuous power of 75 kW. Such first time presented, system level study and experimental characterization for the real time operation will be useful for the high power solid-state amplifier designs, deployed in particle accelerators.

The influence of metabolic syndrome on hemodialysis access patency.

OBJECTIVE: The natural history of patients with metabolic syndrome (MetS) undergoing hemodialysis access placement is unknown. MetS has previously been found as a risk factor for poor outcomes for vascular surgery patients undergoing other interventions. The aim of this is study is to describe the outcomes of MetS patients undergoing primary hemodialysis access placement. METHODS: The medical records of the 187 patients who underwent hemodialysis access placement between 1999 and 2009 at the Veterans Administration Connecticut Healthcare System were reviewed. Survival, primary patency, and secondary patency were evaluated using the Gehan-Breslow test for survival. MetS was defined as the presence of three or more of the following: blood pressure≥130/90 mm Hg; triglycerides≥150 mg/dL; high-density lipoprotein≤50 mg/dL for women and ≤40 mg/dL for men; body mass index≥30 kg/m2; or fasting blood glucose≥110 mg/dL. RESULTS: Of the 187 patients who underwent hemodialysis access placement, 115 (61%) were identified to have MetS. The distribution of MetS factors among all patients was hypertension in 98%, diabetes in 58%, elevated triclyceride in 39%, decreased high-density lipoprotein in 60%, elevated body mass index in 36%, and 39% were currently receiving hemodialysis. Patients were a mean age of 66 years. The median length of follow-up was 4.2 years. The forearm was site of fistula placement in 53%; no difference existed between groups (MetS, 57%; no MetS, 50%; P=.388). The median time to primary failure was 0.46 years for all patients (MetS, 0.555 years; no MetS, 0.436 years; P=.255). Secondary patency was 50% at 1.18 years for all patients (no MetS, 1.94 years; MetS, 0.72 years; P=.024). Median survival duration for all patients was 4.15 years (no MetS, 5.07 years; MetS, 3.63 years; P=.019). CONCLUSIONS: MetS is prevalent among patients undergoing hemodialysis access placement. Patients with MetS have equivalent primary patency rates; however, their survival and cumulative patency rates are significantly lower than in patients without MetS. Patients with MetS form a high-risk group that needs intensive surveillance protocols.

Degenerative (true) superficial temporal artery aneurysm: a case report with review of literature.

This is a case report of a 72-year-old female who presented to our clinic with right temple mass that was found incidentally on a magnetic resonance imaging (MRI) of her head about 2 years ago, as part of a stroke workup. However, it was thought to be a sebaceous cyst and left as such. The patient then experienced a rapid increase in the size of the mass about 2 weeks prior to her presentation to us. On examination, she had a 2 × 2 cm pulsating aneurysmal mass over the right temporal fossa, which was felt to be an aneurysm of the superficial temporal artery and was confirmed by a color duplex ultrasound examination. Open surgical resection with primary ligation of both proximal and distal branches was achieved under local anesthesia. Pathology confirmed a true (degenerative) aneurysm of the superficial temporal artery. Her postoperative course was uneventful. This case report describes this rare entity along with a review of the literature.

Kissing iliac artery stent technique for salvage of hypogastric artery occlusion secondary to iliac artery dissection during endovascular aneurysm repair.

While undergoing endovascular aneurysm repair (EVAR), dissection occurred in bilateral common and external iliac arteries resulting in acute bilateral hypogastric artery occlusion. Attempts were made to reestablish flow to the left internal iliac artery via retrograde ipsilateral approach without success. A left brachial approach was used to gain access to the left internal iliac artery and kissing angioplasty and subsequent stent placement with 2 self-expanding stents was performed raising the iliac bifurcation to the level of the stent graft to salvage the internal iliac artery.

Clinical outcomes for hostile versus favorable aortic neck anatomy in endovascular aortic aneurysm repair using modular devices.

BACKGROUND: Endovascular aneurysm repair (EVAR) is not generally recommended for patients with hostile neck anatomy. This study analyzed the clinical implications of various clinical features of proximal aortic neck anatomy. METHODS: Prospectively collected data from 258 EVAR patients using modular devices were analyzed. Patients were classified as having favorable neck anatomy (FNA) or hostile neck anatomy (HNA). HNA was defined as any or all of length of <10 mm, angle of >60°, diameter of >28 mm, ≥50% circumferential thrombus, ≥50% calcified neck, and reverse taper. Univariate, multivariate, and Kaplan-Meier analyses were used to compare early and late clinical outcomes. RESULTS: FNA was present in 37% and HNA was present in 63%. Clinical and demographic characteristics were comparable. Technical success was 99%. Mean follow-up was 22 months (range, 1-78 months). Perioperative complication rates were 3% for FNA vs 16% for HNA (P = .0027). Perioperative deaths were 0% for FNA and 3% for HNA (P = .2997). Proximal type I early endoleaks (intraoperative) occurred in 9% of FNA vs 22% for HNA (P = .0202). Intraoperative proximal aortic cuffs were used to seal endoleaks in 9% of FNA vs 22% of HNA (P = .0093). At late follow-up, abdominal aortic aneurysm expansion was noted in 6% of FNA vs 7% of HNA (P = .8509). Rates of freedom from late type I endoleaks at 1, 2, 3, and 4 years were 97%, 97%, 97%, and 90% for FNA vs 89%, 89%, 89%, and 89% for HNA (P = .1224); rates for late interventions were 95%, 90%, 90%, and 90% for FNA vs 95%, 93%, 91%, and 85% for HNA (P = .6902). Graft patency at 1, 2, and 3 years was 99%, 99%, and 99% for FNA vs 97%, 92%, and 90% for HNA (P = .0925). The survival rates were 93%, 84%, 76%, and 76% for FNA vs 88%, 82%, 74%, and 66% for HNA (P = .2631). Reverse taper was a significant predictor for early type I endoleak (odds ratio [OR], 5.25, P < .0001), reverse taper (OR, 5.95; P < .0001) and neck length (OR, 4.15; P = .0146) were for aortic cuff use; circumferential thrombus (OR, 2.44; P = .0448), and neck angle (OR, 3.38; P = .009) were for perioperative complications. CONCLUSIONS: Patients with HNA can be treated with EVAR, but with higher rates of early (intraoperative) type I endoleak and intervention. The midterm outcomes are similar to FNA.

Critical appraisal of the Carotid Duplex Consensus criteria in the diagnosis of carotid artery stenosis.

BACKGROUND: Clinicians have relied on published institutional experience for interpreting carotid duplex ultrasound studies (CDUS). This study will validate the ultrasound imaging consensus criteria published in 2003. METHODS: The CDUS and angiography results of 376 carotid arteries were analyzed. Receiver-operating characteristic (ROCs) curves were used to compare peak systolic velocities (PSVs), end-diastolic velocities (EDVs) of the internal carotid artery (ICA), and ICA/common carotid (CCA) ratios in detecting < 50%, 50% to 69% (ICA PSV of 125-230 cm/s), and 70% to 99% (PSV of ≥ 230 cm/s) stenosis according to the consensus criteria. RESULTS: The consensus criteria uses a PSV of 125 to 230 cm/s for detecting angiographic stenosis of 50% to 69%, which has a sensitivity of 93%, specificity of 68%, and overall accuracy of 85%. A PSV of ≥ 230 cm/s for ≥ 70% stenosis had a sensitivity of 99%, specificity of 86%, and overall accuracy of 95%. ROC curves showed that the ICA PSV was significantly better (area under the curve [AUC], 0.97) than EDV (AUC, 0.94) or ICA/CCA ratio (AUC, 0.84; P = .036) in detecting ≥ 70% stenosis and ≥ 50% stenosis. Pearson correlations showed a statistical difference between the correlation of PSV with angiography (0.833; 95% confidence interval [CI], 0.8-0.86), EDV with angiography (0.755; 95% CI, 0.71-0.80), and ICA/CCA systolic ratio with angiography (0.601; 95% CI, 0.53-0.66; P < .0001) in detecting 70% to 99% stenosis. Adding the EDV values or the ratios to the PSV values did not improve accuracy. The consensus criteria for diagnosing 50% to 69% stenosis can be significantly improved by using an ICA PSV of 140 to 230 cm/s, with a sensitivity of 94%, specificity of 92%, and overall accuracy of 92%. CONCLUSIONS: The consensus criteria can be accurately used for diagnosing ≥ 70% stenosis; however, the accuracy can be improved for detecting 50% to 69% stenosis if the ICA PSV is changed to 140 to < 230 cm/s.

The correlation of aortic neck length to early and late outcomes in endovascular aneurysm repair patients.

BACKGROUND: Initially, patients with a short angulated aortic neck were considered unfit for endovascular aneurysm repair (EVAR). Recently, however, more liberal use of EVAR has been advocated. This study analyzes the correlation of aortic neck length to early and late outcomes. METHODS: We analyzed 238 patients who underwent EVAR during a recent 7-year period. All patients were followed up clinically and underwent postoperative duplex ultrasound imaging or computed tomography angiography, which were repeated every 6 months. Aortic neck length was classified into >or=15 mm (L1, n = 195), 10 to <15 mm (L2, n = 24), and <10 mm (L3, n = 17). Kaplan-Meier methods were used to estimate freedom from late endoleak, early and late reintervention, and survival. RESULTS: Analyzed were 49 Ancure, 47 AneuRx, 104 Excluder, and 38 Zenith grafts. The mean follow-up was 24.7 months (range, 1-87 months). The initial technical success was 99%. The perioperative complication rates for groups L1, L2, and L3 were 13%, 21%, and 24%, respectively (P = .289). Proximal type I early endoleaks occurred in 12%, 42%, and 53% in groups L1, L2, and L3, respectively (P < .001). Intraoperative proximal aortic cuffs were needed to seal proximal type I endoleaks in 10%, 38%, and 47% in L1, L2, and L3 groups, respectively (P < .0001). However, the rate of late reintervention was comparable in all groups. Postoperatively, the size of the abdominal aortic aneurysm decreased or remained unchanged in 95%, 94%, and 88% in L1, L2, and L3, respectively (P = .660). Rates of freedom from late type I endoleak at 1, 2, and 3 years were 84%, 82%, and 80% for L1; 68%, 54%, and 54% for L2; and 71%, 71%, and 53% for L3 (P = .0263). Rates of freedom from late intervention at 1, 2, and 3 years were 96%, 94%, and 92% for L1; and 94%, 83%, and 83% for L2; and 93%, 93%, and 93% for L3 (P = .5334). CONCLUSIONS: EVAR can be used for patients with a short aortic neck; however, it was associated with a significantly higher rate of early and late type I endoleaks, resulting in an increased use of proximal aortic cuffs for sealing the endoleaks.

Design of high power radio frequency radial combiner for proton accelerator.

A simplified design method has been proposed for systematic design of novel radio frequency (rf) power combiner and divider, incorporating radial slab-line structure, without using isolation resistor and external tuning mechanism. Due to low insertion loss, high power capability, and rigid mechanical configuration, this structure is advantageous for modern solid state rf power source used for feeding rf energy to superconducting accelerating structures. Analysis, based on equivalent circuit and radial transmission line approximation, provides simple design formula for calculating combiner parameters. Based on this method, novel 8-way and 16-way power combiners, with power handling capability of 4 kW, have been designed, as part of high power solid state rf amplifier development. Detailed experiments showed good performance in accordance with theory.

Prognostic factors in primary adenocarcinoma of the small intestine: 13-year single institution experience.

BACKGROUND: Adenocarcinoma of the small bowel is a relatively rare malignancy as compared to the other malignancies of the gastrointestinal tract. Nonspecific presentation and infrequent occurrence often leads to a delay in diagnosis and consequent poor prognosis. Various other factors are of prognostic importance while managing these tumors. METHODS: The medical records of a total of 27 patients treated for adenocarcinoma of the small bowel at Providence Hospital and Medical Centers from year 1990 through 2003 were reviewed retrospectively. Data were analyzed using SPSS software (version 10.0; SPSS, Inc., Chicago, IL). Survival analyses were calculated using the Kaplan Meier method with the log rank test to assess the statistical significance. The socio-demographics (age, gender) were calculated using frequency analyses. RESULTS: The patients included nine males and eighteen females with a median age at diagnosis of 62 years. Only 48% of the patients had an accurate preoperative diagnosis while another 33% had a diagnosis suspicious of small bowel malignancy. None of the patients presented in stage 1. The cumulative five-year survival was 30% while the median survival was 3.3 years. There was no 30-day mortality in the postoperative period in our series. CONCLUSION: The univariate analysis demonstrated that tumor grade, stage at presentation, lymph nodal metastasis and resection margins were significant predictors of survival.

Retroperitoneoscopic lumbar sympathectomy for buerger's disease: a novel technique.

BACKGROUND: The conventional lumbar sympathectomy procedure through the extraperitoneal route requires a muscle cutting-splitting incision, which leads to significant postoperative pain and prolonged convalescence. With increasing experience in retroperitoneoscopic procedures, we did a pilot study to explore the role of retroperitoneoscopy in lumbar sympathectomy. We describe herein our technique used for the surgery. METHODS: The patient was placed in a lateral position. A 15-mm incision was made just below the 12th rib, and retroperitoneal space was created using blunt finger dissection. A custom-made, large balloon was inserted and inflated with the equivalent of 750 mL to 1000 mL of saline. The second 10-mm port was placed in line with the first port above the iliac crest. The third and fourth 5-mm ports were placed anterior to the first 2 ports. Peritoneum was retracted anteriorly. The medial border of the psoas muscle was used as a landmark and a chain identified immediately medial to it. Lumbar vessels were ligated on the right side. The first to fourth lumbar sympathetic ganglia were removed with the intervening chain. The port sites were closed without a drain. RESULTS: We attempted and successfully completed this procedure in 8 patients; 6 on the left side and 2 on the right side. The average operating time was 38 minutes. The mean hospital stay was 1.5 days. All patients had symptomatic pain relief and clinical improvement. CONCLUSIONS: Retroperitoneoscopic lumbar sympathectomy is a safe and effective procedure. It has a short convalescent time and minimal morbidity; hence, it is a viable alternative for the open procedure.