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Dive into the research topics where Christopher J. Allen is active.

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Featured researches published by Christopher J. Allen.


Journal of The American College of Surgeons | 2003

Five-year comprehensive outcomes evaluation in 181 patients after laparoscopic Nissen fundoplication☆

Mehran Anvari; Christopher J. Allen

BACKGROUND We conducted an objective followup of 181 patients after laparoscopic Nissen fundoplication during a 5-year period after surgery. STUDY DESIGN Patients underwent 24-hour pH recording, esophageal manometry, and symptom score assessment for six gastroesophageal reflux disease symptoms preoperatively and at 6 months, 2 years, and 5 years after surgery. RESULTS Laparoscopic fundoplication was associated with a significant (p < 0.0001) increase in lower esophageal sphincter pressure and a significant (p < 0.0001) drop in duration of acid reflux in 24 hours, and symptom score, 6, 24, and 60 months after surgery when compared with preoperative values. Twenty-one patients (12%) have experienced recurrence of reflux-type symptoms, but only six have required repeat surgery. Lower esophageal sphincter tone dropped between 6 months and 5 years after surgery, but was still an effective antireflux barrier. Patient satisfaction with surgery dropped over the 5-year followup but remained high, at 86%, after 5 years. CONCLUSIONS Laparoscopic Nissen fundoplication remains an effective antireflux procedure at 5 years.


Thorax | 1998

Gastro-oesophageal reflux related cough and its response to laparoscopic fundoplication.

Christopher J. Allen; Mehran Anvari

BACKGROUND This study was designed to determine prospectively the rate of cough before and after laparoscopic Nissen fundoplication performed for the control of gastro-oesophageal reflux disease. METHODS One hundred and ninety five consecutive patients (76 men) of mean (SD) age 46.9 (14.1) years with proven gastro-oesophageal reflux disease, who were either on long term omeprazole (n = 187) or who had not responded to a trial of omeprazole (n = 8), took part in the study which was carried out in a university teaching hospital that included a regional respiratory referral centre. Patients underwent oesophageal manometry, 24 hour oesophageal pH testing, and symptom score evaluation by an independent observer before and six months after laparoscopic Nissen fundoplication. RESULTS One hundred and thirty three patients presented with reflux symptoms and 62 with respiratory symptoms; 68% of patients complained of cough before surgery (86% with respiratory symptoms, 60% with gastrointestinal symptoms). The percentage reflux time in 24 hours fell significantly (p<0.0001) from a mean (SD) of 9.38 (10.99)% to 1.22 (2.92)%, lower oesophageal sphincter tone rose significantly (p<0.0001) from a mean (SD) of 7.71 (5.90) mm Hg to 21.74 (10.84) mm Hg, and the cough score fell from a median value of 8.0 (IQR 12.0) to 0 (IQR 3) following surgery. Of the patients with cough, 51% were cough free after surgery and 31% improved. The patients with respiratory symptoms had a higher cough score before (median 12.0 (IQR 5.5) versus 4.0 (IQR 8.75), p<0.0001) and after surgery (median 1 (7.5) versus 0.0 (IQR 1.0), p = 0.0045) than those with gastrointestinal symptoms. CONCLUSIONS Patients who present to gastroenterologists with severe reflux commonly complain of cough. Laparoscopic Nissen fundoplication is effective in the control of cough in patients with gastro-oesophageal reflux disease, with or without primary respiratory disease.


Surgical Innovation | 2006

A Randomized Controlled Trial of Laparoscopic Nissen Fundoplication Versus Proton Pump Inhibitors for Treatment of Patients With Chronic Gastroesophageal Reflux Disease: One-Year Follow-Up

Mehran Anvari; Christopher J. Allen; John K. Marshall; David Armstrong; Ron Goeree; Wendy J. Ungar; Charles H. Goldsmith

A randomized controlled trial conducted in patients with gastroesophageal reflux disease compared optimized medical therapy using proton pump inhibitor (n = 52) with laparoscopic Nissen fundoplication (n = 52). Patients were monitored for 1 year. The primary end point was frequency of gastroesophageal reflux dis-ease symptoms. Surgical patients had improved symptoms, pH control, and overall quality of life health index after surgery at 1 year compared with the medical group. The overall gastroesophageal reflux disease symptom score at 1 year was unchanged in the medical patients, but improved in the surgical patients. Fourteen patients in the medical arm experienced symptom relapse requiring titration of the proton pump inhibitor dose, but 6 had satisfactory symptom remission. No surgical patients required additional treatment for symptom control. Patients controlled on long-term proton pump inhibitor therapy for chronic gastroesophageal reflux disease are excellent surgical candidates and should experience improved symptom control after surgery at 1 year.


Clinical & Experimental Allergy | 2007

Effect of obesity on airway inflammation: a cross-sectional analysis of body mass index and sputum cell counts.

David C. Todd; S. Armstrong; Liesel D'silva; Christopher J. Allen; F.E. Hargreave; Krishnan Parameswaran

Background Several observational studies have demonstrated an association between obesity and asthma. Studies evaluating exhaled nitric oxide levels and obesity have revealed that a higher body mass index (BMI) is associated with elevated exhaled nitric oxide levels. Airway inflammation using sputum cell counts has not been assessed in obese patients with airway diseases.


Annals of Surgery | 1998

Laparoscopic Nissen Fundoplication: Two-year Comprehensive Follow-up of a Technique of Minimal Paraesophageal Dissection

Mehran Anvari; Christopher J. Allen

OBJECTIVE To provide a comprehensive follow-up of 381 patients after laparoscopic Nissen fundoplication (LNF) using a technique of minimal paraesophageal dissection. METHODS Patients underwent a 24-hour pH recording, esophageal manometry, and symptom score assessment for six symptoms of gastroesophageal reflux disease preoperatively. To date, 260 patients have undergone repeat studies at 6 months and 108 patients at 2 years. RESULTS LNF was associated with a significant (p < 0.0001) increase in the lower esophageal sphincter (LES) pressure and a significant (p < 0.0001) drop in duration of acid reflux in 24 hours and symptom score 6 and 24 months after surgery when compared to preoperative values. Twelve patients (3%) have experienced recurrence of reflux symptoms, 8 presenting in the first 6 months and 4 by the second year after surgery, but only 1 has required repeat surgery. The incidence of clinical dysphagia was found to be 1.3% of the patient group. CONCLUSIONS LNF remains an effective antireflux procedure at 2 years. Most recurrences occur early, and there is no significant deterioration in the high-pressure zone at the LES, the percentage reflux in 24 hours, or symptom control between 6 months and 2 years after surgery, suggesting that the long-term results should be satisfactory.


Surgical Endoscopy and Other Interventional Techniques | 2004

Does laparoscopic fundoplication provide long-term control of gastroesophageal reflux related cough?

Christopher J. Allen; Mehran Anvari

Background: Of patients with chronic cough, 21% have GERD. Up to half of these patients may not respond adequately to medical, but the long-term results of antireflux surgery for cough is unknown. Methods: A total of 905 patients (209 with respiratory symptoms, mainly cough) underwent laparoscopic Nissen fundoplication. Preoperatively patients underwent esophageal motility studies, 24-h pH monitoring, and symptom evaluation using a validated scale. Of eligible patients, 81% were followed at 6 months, 73% at 2 years, and 60% at 5 years. Results: Before surgery, 83% of respiratory patients (RP) and 51% of nonrespiratory patients (NRP) had cough. RP had higher cough scores (p < 0.0001), but improvement in cough compared to baseline was similar in the RP and NRP (p = 0.1105 at 6 months, 0.4206 at 2 years, and 0.1348 at 5 years). Cough improved in 83% at 6 months, 74% at 2 years, and 71% at 5 years. Conclusions: Laparoscopic Nissen fundoplication is successful in the long-term control of GERD-related cough, even in patients who fail medical therapy.


General Hospital Psychiatry | 1997

Integrating mental health services within primary care : A Canadian program

Nick Kates; Marilyn Craven; Anne Marie Crustolo; Lambrina Nikolaou; Christopher J. Allen

The increasingly prominent role of the family physician in delivering mental health care can be enhanced if productive and collaborative relationships can be established with local mental health services. This paper describes a Canadian program that has achieved this by bringing mental health counselors and psychiatrists into the offices of 87 family physicians in 35 practices in a community in Southern Ontario. The paper describes the program, the activities of counselors and psychiatrists within the practices, and the administrative structures set up to coordinate these activities. Data is presented from the evaluation of the first year of the programs operation (13 practices and 45 family physicians) during which time 3085 referrals were received. The program made mental health care more available and accessible, increased continuity of care, provided additional support for the family physician, offered new opportunities for continuing education, and led to a reduced and more efficient use of other mental health services. The components of the program can be adapted to most communities.


Current Oncology | 2012

Fine-needle aspiration biopsy versus core-needle biopsy in diagnosing lung cancer: a systematic review

X. Yao; Marcio M. Gomes; M.S. Tsao; Christopher J. Allen; W. Geddie; Harmanjatinder S. Sekhon

BACKGROUND Lung cancer leads cancer-related mortality in the world. The objective of the present systematic review was to compare fine-needle aspiration biopsy (fnab) with core-needle biopsy (cnb) for diagnostic characteristics and yields for diagnosing lung cancer in patients with lung lesions. METHODS The medline and embase databases (from January 1, 1990, to September 14, 2009), the Cochrane Library (to Issue 4, 2009), and selected guideline Web sites were searched for relevant articles. RESULTS For overall diagnostic characteristics (benign vs. malignant) of fnab and cnb, the ranges of sensitivity were 81.3%-90.8% and 85.7-97.4% respectively; of specificity, 75.4%-100.0% and 88.6%-100.0%; and of accuracy, 79.7%-91.8% and 89.0%-96.9%. For specific diagnostic characteristics of fnab and cnb (identifying the histologic subtype of malignancies or the specific benign diagnoses), the ranges of sensitivity were 56.3%-86.5% and 56.5-88.7% respectively; of specificity, 6.7%-57.1% and 52.4%-100.0%; and of accuracy, 40.4%-81.2% and 66.7%-93.2%. Compared with fnab, cnb did not result in a higher complication rate (pneumothorax or hemoptysis). No study has yet compared the diagnostic yields of fnab and of cnb for molecular predictive-marker studies in patients with lung lesions. DISCUSSION AND CONCLUSIONS The evidence is currently insufficient to support a difference between fnab and cnb in identifying lung malignancies in patients with lung lesions. Compared with fnab, cnb might have a higher specificity to diagnose specific benign lesions. Well-designed, good-quality studies comparing fnab with cnb for diagnostic characteristics and yields in diagnosing lung cancer should be encouraged.


Surgical Endoscopy and Other Interventional Techniques | 2002

Preoperative symptom evaluation and esophageal acid infusion predict response to laparoscopic Nissen fundoplication in gastroesophageal reflux patients who present with cough

Christopher J. Allen; Mehran Anvari

Background: Most patients with cough and gastroesophageal reflux disease (GERD) improve on medical treatment with proton pump inhibitors (PPI). Nonresponders may be considered for antireftux surgery, but the selection of patients is difficult. Methods: We have performed laparoscopic Nissen fundoplications (LNF) in 677 patients. Of these patients, 81% have undergone 6-month follow-up assessment with 24-h pH testing, esophageal manometry, symptom scores, and quality-of-life scores. Results: LNF controlled heartburn in 93% and improved cough in 81%. Stepwise multiple regression showed that the preoperative cough score (r = 0.620, p <0.0001) and change in cough on and off PPI (r = 0.296, p = 0.0002) predicted improvement after surgery. A positive result on a randomized acid infusion test was associated with a greater improvement in cough after surgery (p = 0.0243). Conclusion: An acid infusion test and assessment of cough on and off PPI may be useful preoperative tools for the selection of patients with cough for LNF.


The Canadian Journal of Psychiatry | 1997

Sharing care : The psychiatrist in the family physician's office

Nick Kates; Marilyn Craven; Anne-Marie Crustolo; Lambrina Nikolaou; Christopher J. Allen; Sheryl Farrar

Objective: One way of strengthening ties between primary care providers and psychiatrists is for a psychiatrist to visit a primary care practice on a regular basis to see and discuss patients and to provide educational input and advice for family physicians. This paper reviews the experiences of a program in Hamilton, Ontario that brings psychiatrists and counsellors into the offices of 88 local family physicians in 36 practices. Method: Data are presented based on the activities of psychiatrists working in 13 practices over a 2-year period. Data were gathered from forms routinely completed by family physicians when making a referral and by psychiatrists whenever they saw a new case. An annual satisfaction questionnaire for all providers participating in the program was also used to gather information. Results: Over a 2-year period, 1021 patients were seen in consultation by one full-time equivalent psychiatrist. The average duration of a consultation was 51 minutes, and a family member was present for 12% of the visits. Twenty-one percent of the patients were seen for at least one follow-up visit, 75% of which were prearranged. In addition, 1515 cases were discussed during these visits without the patient being seen. All participants had a high satisfaction rating for their involvement with the project. Conclusions: Benefits of this approach include increased accessibility to psychiatric consultation, enhanced continuity of care, support for family physicians, and improved communication between psychiatrists and family physicians. This model, which has great potential for innovative approaches to continuing education and resident placements, demands new skills of participating psychiatrists.

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