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Dive into the research topics where Mary R. Kwaan is active.

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Featured researches published by Mary R. Kwaan.


Diseases of The Colon & Rectum | 2005

Risk Factors for Perineal Wound Complications Following Abdominoperineal Resection

Caprice K. Christian; Mary R. Kwaan; Rebecca A. Betensky; Elizabeth M. Breen; Michael J. Zinner; Ronald Bleday

PURPOSEPerineal wound complications are common following abdominoperineal resection. This study investigates the factors contributing to these complications.METHODSPatients undergoing abdominoperineal resection at our institution from June 1997 to May 2003 were reviewed. Significant predictors associated with minor (separation <2 cm, stitch abscesses, or sinus tracts) or major (>2 cm of separation, reoperation required, or readmission) wound complications were ascertained.RESULTSOf 153 patients, there were 22 major (14 percent) and 32 minor (24 percent) wound complications. Patients with anal cancer had a higher rate of major complications than those with rectal cancer or inflammatory bowel disease. Minor wound complications were more common in patients with anal cancer and inflammatory bowel disease than those with rectal cancer. Factors associated with a higher rate of major wound complications included flap closure, tumor size, body mass index, diabetes, and indication for the procedure. When the subset of patients with rectal cancer was considered, higher rates of major wounds were associated with increased body mass index, diabetes, and stage. Minor complications were associated with a two-team approach and increasing body mass index.CONCLUSIONSThis is currently the largest review of perineal wound complications following abdominoperineal resection. Patients with anal cancer and inflammatory bowel disease were at higher risk for perineal wound complications than those with rectal cancer. Preoperative radiation and primary closure were not associated with increased complications following abdominoperineal resection for rectal cancer.


Annals of Surgery | 2011

Operative outcomes beyond 30-day mortality: Colorectal cancer surgery in oldest old

Helen M. Parsons; Elizabeth B. Habermann; Mary R. Kwaan; Michael P. Spencer; William G. Henderson; David A. Rothenberger

Background: Resections for elderly colorectal cancer (CRC) are forecasted to grow, particularly in those beyond the age limit of screening (>80 years). However, literature on operative outcomes after CRC procedures in the oldest old is focused primarily on operative mortality. We hypothesize that older age will additionally impact operative morbidity after CRC resections in a multihospital, risk-adjusted database. Study Design: We identified 19,375 patients >40 years who underwent CRC procedures in the 2005 to 2008 American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database. Pre-, intra-, and postoperative factors were compared by age groups. Multivariable techniques were used to assess the effects of older age on operative outcome measures, adjusting for covariates. Results: Over 20% of our cohort was older than 80 years. Of those, 17% developed major complications and 29% experienced prolonged length of stay (LOS). Older patients also experienced higher rates of 30-day operative mortality (>80 years vs. 45–55 years; 6% vs. <1%), major complications (>80 years vs. 45–55 years; 21% vs. 14%), and prolonged LOS after open (>80 years vs. 45–55 years; 37% vs. 24%) and laparoscopic procedures (>80 years vs. 45–55 years; 40.5% vs. 18%). These unadjusted comparisons persisted in multivariable analyses demonstrating that older age independently predicted worse operative outcomes after CRC procedures. Conclusions: The effects of older age extend to other important outcome measures after CRC procedures beyond operative mortality. As one of the largest multihospital studies, our study identified increased morbidity in the oldest old, a growing population. Our results should stimulate review of current policy and resource allocation.


Archives of Surgery | 2008

Rectal Carcinoid Tumors: Review of Results After Endoscopic and Surgical Therapy

Mary R. Kwaan; Joel E. Goldberg; Ronald Bleday

OBJECTIVE To assess whether endoscopic treatment can clear local disease in patients with carcinoid tumor. DESIGN Retrospective cohort study. SETTING Tertiary care academic medical center. PATIENTS All patients diagnosed as having a neuroendocrine tumor or carcinoid tumor of the rectum who were evaluated at our institution between January 1, 1990, and December 31, 2006. MAIN OUTCOME MEASURE Margin status of tumor resection. RESULTS Eighty-five patients were identified (median age at diagnosis, 55 years). Thirty-three tumors (39%) were asymptomatic and diagnosed during screening colonoscopy. Eleven tumors (13%) were metastatic at presentation. Of the 85 tumors, 48 (56%) were smaller than 1.0 cm. Endoscopic therapy was performed in 46 patients (54%). Of these, 38 patients (83%) had tumors with positive or indeterminate margins on histologic examination; of whom 6 (16%) had residual tumor on subsequent endoscopy and 1 (3%) had recurrence as metastatic disease. One patient who had a negative margin had residual tumor on follow-up. Thirty-one patients (36%) underwent surgical resection; of these, 23 (74%) underwent transanal excision or transanal endoscopic microsurgery, 6 (19%) underwent low anterior resection, and 2 (6%) underwent abdominoperineal resection. Eight patients who did not receive local clearance of tumor had metastases on presentation, had another active malignant neoplasm, or refused further surgical treatment. Among the 85 patients, 4 metastases occurred during follow-up, including 2 from tumors smaller than 1.0 cm at presentation. CONCLUSIONS Endoscopic treatment is sufficient for tumors that are small, for tumors limited to the mucosa, and when a margin is negative for tumor. Transanal excision should be considered when margins of endoscopic resection are positive. We recommend rectal resection for tumors that are 1.0 to 1.9 cm and have high-risk features.


World Journal of Surgery | 2013

The evolving role of laparoscopy in colonic diverticular disease: A systematic review

Wolfgang B. Gaertner; Mary R. Kwaan; Robert D. Madoff; David Willis; George E. Belzer; David A. Rothenberger; Genevieve B. Melton

BackgroundA PubMed search of the biomedical literature was carried out to systematically review the role of laparoscopy in colonic diverticular disease. All original reports comparing elective laparoscopic, hand-assisted, and open colon resection for diverticular disease of the colon, as well as original reports evaluating outcomes after laparoscopic lavage for acute diverticulitis, were considered. Of the 21 articles chosen for final review, nine evaluated laparoscopic versus open elective resection, six compared hand-assisted colon resection versus conventional laparoscopic resection, and six considered laparoscopic lavage. Five were randomized controlled trials.ResultsElective laparoscopic colon resection for diverticular disease is associated with increased operative time, decreased postoperative pain, fewer postoperative complications, less paralytic ileus, and shorter hospital stay compared to open colectomy. Laparoscopic lavage and drainage appears to be a safe and effective therapy for selected patients with complicated diverticulitis.ConclusionsElective laparoscopic colectomy for diverticular disease is associated with decreased postoperative morbidity compared to open colectomy, leading to shorter hospital stay and fewer costs. Laparoscopic lavage has an increasing but poorly defined role in complicated diverticulitis.


Diseases of The Colon & Rectum | 2013

Percutaneous drainage of colonic diverticular abscess: is colon resection necessary?

Wolfgang B. Gaertner; David Willis; Robert D. Madoff; David A. Rothenberger; Mary R. Kwaan; George E. Belzer; Genevieve B. Melton

BACKGROUND: Recurrent diverticulitis has been reported in up to 30% to 40% of patients who recover from an episode of colonic diverticular abscess, so elective interval resection is traditionally recommended. OBJECTIVE: The aim of this study was to review the outcomes of patients who underwent percutaneous drainage of colonic diverticular abscess without subsequent operative intervention. DESIGN: This was an observational study. SETTINGS: This investigation was conducted at a tertiary care academic medical center and a single-hospital health system. PATIENTS: Patients treated for symptomatic colonic diverticular abscess from 2002 through 2007 were included. MAIN OUTCOME MEASURES: The primary outcomes measured were complications, recurrence, and colectomy-free survival. RESULTS: Two hundred eighteen patients underwent percutaneous drainage of colonic diverticular abscesses. Thirty-two patients (15%) did not undergo subsequent colonic resection. Abscess location was pelvic (n = 9) and paracolic (n = 23), the mean abscess size was 4.2 cm, and the median duration of percutaneous drainage was 20 days. The comorbidities of this group of patients included severe cardiac disease (n = 16), immunodeficiency (n = 7), and severe pulmonary disease (n = 6). Freedom from recurrence at 7.4 years was 0.58 (95% CI 0.42–0.73). All recurrences were managed nonoperatively. Recurrence was significantly associated with an abscess size larger than 5 cm. Colectomy-free survival at 7.4 years was 0.17 (95% CI 0.13–0.21). LIMITATIONS: This study was limited by its retrospective, nonexperimental design and short follow-up. CONCLUSION: In selected patients, observation after percutaneous drainage of colonic diverticular abscess appears to be a safe and low-risk management option.


JAMA Surgery | 2013

Are right-sided colectomy outcomes different from left-sided colectomy outcomes?: Study of patients with colon cancer in the ACS NSQIP database

Mary R. Kwaan; Helen M. Parsons; Christopher J. Chow; David A. Rothenberger; Elizabeth B. Habermann

IMPORTANCE Optimization of surgical outcomes after colectomy continues to be actively studied, but most studies group right-sided and left-sided colectomies together. OBJECTIVE To determine whether the complication rate differs between right-sided and left-sided colectomies for cancer. As a secondary analysis, we investigated hospital length of stay. DESIGN We identified patients who underwent colectomy for colon cancer in the 2005-2008 American College of Surgeons National Surgical Quality Improvement Program database and stratified cases by right and left side. Preoperative, intraoperative, and postoperative factors were compared. Multivariable techniques were used to assess the impact of the side of colectomy on operative outcome measures, adjusting for covariates. SETTING Hospitals within the American College of Surgeons National Surgical Quality Improvement Program database. PATIENTS We identified 4875 patients who underwent elective laparoscopic or open colectomy for right-sided or left-sided colon cancer in the database. MAIN OUTCOMES AND MEASURES Major complications and surgical site infection (SSI) rates. RESULTS In the 4875 colectomies studied, a laparoscopic approach was used in 42% of cases and at similar frequency in right-sided and left-sided colectomies. Thirty-day mortality (1.5%) was similar in both groups. Major complications were seen in 17% of patients in each group. Superficial SSI was more likely to occur in patients who underwent left-sided colectomy (8.2% vs 5.9%). Among patients with postoperative sepsis or deep or organ space SSIs, more patients in the left-sided colectomy group underwent reoperation compared with the right-sided colectomy group (56% vs 30%). Laparoscopic right-sided colectomy patients were more likely to have a prolonged hospital length of stay than laparoscopic left-sided colectomy patients (odds ratio, 1.39; 95% CI, 1.09-1.78). CONCLUSIONS AND RELEVANCE The outcomes after colectomy for cancer are comparable in right-sided and left-sided resections, except for in the case of superficial SSI, which is less common in right-sided resections. Further research on SSI after colectomy should incorporate right vs left side as a potential preoperative risk factor.


Cancer | 2013

Adjuvant chemotherapy for stage III colon cancer in the oldest old: Results beyond clinical guidelines

Anasooya Abraham; Elizabeth B. Habermann; David A. Rothenberger; Mary R. Kwaan; Armin D. Weinberg; Helen M. Parsons; Pankaj Gupta

Randomized trials demonstrating the benefits of chemotherapy in patients with American Joint Committee on Cancer stage III colon cancer underrepresent persons aged ≥ 75 years. The generalizability of these studies to a growing elderly population remains unknown.


Diseases of The Colon & Rectum | 2012

Colonic volvulus: presentation and management in metropolitan Minnesota, United States.

Brian R. Swenson; Mary R. Kwaan; Nora E. Burkart; Yan Wang; Robert D. Madoff; David A. Rothenberger; Genevieve B. Melton

BACKGROUND: Management approaches for colonic volvulus are infrequently described in the literature in the United States, and many studies only report operative cases. OBJECTIVE: The aim of this study was to define the demographics, diagnostic and treatment approaches, and outcomes for patients with this disorder in the United States. DESIGN: This study is a retrospective review. SETTINGS: The study was conducted at a 7-hospital health system. PATIENTS: All patients diagnosed with colonic volvulus by International Classification of Diseases, Ninth Revision code were included. MAIN OUTCOME MEASURES: The primary outcomes measured were recurrence, complications, and mortality. RESULTS: One hundred three cases of volvulus (50 sigmoid, 53 cecal) were identified in 92 patients. Compared with cecal volvulus, sigmoid volvulus was more common in men, patients with neurologic diagnoses, and residents of skilled nursing home. Eighty-five percent of the cases presented were acutely obstructed. The diagnosis was established by abdominal x-ray (17%), contrast enema study (27%), CT scan (35%), or laparotomy (17%). Abdominal x-rays were insufficient for definitive diagnosis in 85% of cecal and 49% of sigmoid cases (p = 0.002). All patients with cecal volvulus were treated surgically. Seventy-nine percent of patients with sigmoid volvulus underwent successful nonoperative reduction, of whom 38% had subsequent surgery. Fifty-eight percent of patients with sigmoid volvulus were treated operatively. Resection with primary anastomosis was chosen in most cases (78%). Resection with end ostomy (10%), reduction and pexy (7%), and reduction alone (4%) were other approaches. The mortality rate was 5% (cecal 0%, sigmoid 10%; p = 0.012). There were no readmissions for recurrent cecal volvulus. Nonoperative treatment for sigmoid volvulus often failed (48%). Complication rates were higher in sigmoid volvulus cases (cecal 17%, sigmoid 34%; p = 0.047). LIMITATIONS: This study was limited by its retrospective, nonexperimental design. CONCLUSIONS: Although incidences of cecal and sigmoid volvulus are similar in the present series, sigmoid volvuli are more common in men, individuals with neurologic disease, and residents of nursing homes. Plain radiograph is insufficient to confirm cecal volvulus. The diagnosis is most often made with CT scans. The nonoperative management of sigmoid volvulus is associated with a high recurrence rate.


Gastroenterology Research and Practice | 2011

Eosinophilic colitis: university of Minnesota experience and literature review.

Wolfgang B. Gaertner; Jennifer E. MacDonald; Mary R. Kwaan; Christopher Shepela; Robert D. Madoff; Jose Jessurun; Genevieve B. Melton

Eosinophilic colitis is a rare form of primary eosinophilic gastrointestinal disease that is poorly understood. Neonates and young adults are more frequently affected. Clinical presentation is highly variable depending on the depth of inflammatory response (mucosal, transmural, or serosal). The pathophysiology of eosinophilic colitis is unclear but is suspected to be related to a hypersensitivity reaction given its correlation with other atopic disorders and clinical response to corticosteroid therapy. Diagnosis is that of exclusion and differential diagnoses are many because colonic tissue eosinophilia may occur with other colitides (parasitic, drug-induced, inflammatory bowel disease, and various connective tissue disorders). Similar to other eosinophilic gastrointestinal disorders, steroid-based therapy and diet modification achieve very good and durable responses. In this paper, we present our experience with this rare pathology. Five patients (3 pediatric and 2 adults) presented with diarrhea and hematochezia. Mean age at presentation was 26 years. Mean duration of symptoms before pathologic diagnosis was 8 months. Mean eosinophil count per patient was 31 per high-power field. The pediatric patients responded very well to dietary modifications, with no recurrences. The adult patients were treated with steroids and did not respond. Overall mean followup was 22 (range, 2–48) months.


Diseases of The Colon & Rectum | 2013

Readmission after colorectal surgery is related to preoperative clinical conditions and major complications.

Mary R. Kwaan; Sarah A. Vogler; Mark Y. Sun; Anne Marie E. Sirany; Genevieve B. Melton; Robert D. Madoff; David A. Rothenberger

BACKGROUND: Hospital readmission is increasingly perceived as a marker of quality and is poorly investigated in patients receiving colorectal surgery. OBJECTIVE: The objective of this study was to describe patterns and etiology of readmission, to determine the rate of readmission, and to identify risk factors for readmission after colorectal surgery. DESIGN: This study is a retrospective medical chart review. Significant (p < 0.1) preoperative and perioperative factors associated with readmission on univariate analysis were examined in a multivariable model. SETTING: The investigation was conducted in a tertiary care hospital. PATIENTS: Patients included adults undergoing major colorectal operations by colorectal surgeons at the University of Minnesota in 2008–2009. MAIN OUTCOME MEASURES: The primary outcome measure was hospital readmission at 60 days. RESULTS: The study included 220 patients. Common surgical indications were inflammatory bowel disease (21%), colorectal cancer (39%), and diverticular disease (13%), and 11% were emergencies. Readmissions at 60 days occurred in 25% (n = 54), mostly because of major complications (57%), nonspecific nausea, vomiting and/or pain (18%), dehydration (11%), and wound infections (11%). Predictors of readmission in multivariable analysis were major complications (OR, 13.0), female sex (OR, 5.9), prednisone use (OR, 4.3), BMI ≥30 (OR, 2.6), and preoperative weight loss (OR, 3.4). Age and comorbidity (Charlson score) were not predictors. LIMITATIONS: This was a retrospective study at a single institution, with a small sample size. CONCLUSIONS: Predictors of readmission were major complications and immediate preoperative condition of the patients. Comorbidity profiling does not capture readmission risk. Because most readmissions relate to complications, further efforts to prevent these will improve readmission rates.

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Yunhua Fan

University of Minnesota

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Anne Marie E. Sirany

Hennepin County Medical Center

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Yan Wang

University of Minnesota

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Atul A. Gawande

Brigham and Women's Hospital

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