Sample Size Calculations in Simple Linear Regression: A New Approach.

The problem tackled is the determination of sample size for a given level and power in the context of a simple linear regression model. The standard approach deals with planned experiments in which the predictor X is observed for a number n of times and the corresponding observations on the response variable Y are to be drawn. The statistic that is used is built on the least squares' estimator of the slope parameter.

Comparison of Harmless Acute Pancreatitis Score with Ranson's Score in Predicting the Severity of Acute Pancreatitis.

Objective: To determine the predictability of harmless acute pancreatitis score (HAPS) in determining the severity of acute pancreatitis (AP) and compare it with Ranson's score.

Study Design: Prospective cohort study.

Place And Duration Of Study: King Saud Medical City, Riyadh, Kingdom of Saudi Arabia, between January 2012 and December 2015.

Day-case laparoscopic cholecystectomy.

Objectives: To assess the safety and feasibility of laparoscopic cholecystectomy as a day-case procedure.

Methods: All consecutive patients who were admitted to the day-surgery unit for laparoscopic cholecystectomy at the Department of Surgery, King Saud Medical City, Riyadh, Saudi Arabia from July 2009 to June 2013 were considered for this retrospective study. The medical records were reviewed for age, gender, presenting symptoms, laboratory findings, imaging studies, American Society of Anesthesiology (ASA) grade, anesthesia, conversion to open cholecystectomy, complications, the operating surgeons, pain management, nausea, and vomiting, overnight stay, readmission, morbidity, mortality, and outpatient follow up were collected and analyzed.

Early endoscopic retrograde cholangiopancreatography in mild gallstone pancreatitis with deranged liver function test. A 7-year experience in central Saudi Arabia.

Objective: To determine the use of liver function tests (LFTs) as a selection tool for preoperative endoscopic retrograde cholangiopancreatography (ERCP) in patients with mild gallstone pancreatitis.

Methods: All patients admitted with mild gallstone pancreatitis with deranged LFTs in King Saud Medical City, Riyadh, Kingdom of Saudi Arabia between January 2006 and February 2013 were studied retrospectively. Patients' demography, symptoms, laboratory values, imaging studies, ERCP findings, complications and its treatment, surgical intervention, intraoperative and postoperative findings, mortality, and outpatient follow up were collected and analyzed.

Role of postoperative antibiotics after appendectomy in non-perforated appendicitis.

Objective: To determine the role of postoperative antibiotics in reducing the surgical site infections (SSIs) after open appendectomy in patients with non-perforated appendicitis (NPA).

Study Design: Randomized controlled trial.

Place And Duration Of Study: The Department of Surgery, King Saud Medical City, Riyadh, Kingdom of Saudi Arabia, from January 2010 to July 2011.

Management of appendiceal abscess. A 10-year experience in Central Saudi Arabia.

Objective: To study the outcome of patients with appendiceal abscess (AA) following immediate operative and non-operative management in terms of complications and hospital stay.

Methods: Medical records of all adult patients treated for AA between July 2002 and June 2011 in the Department of Surgery, King Saud Medical City, Riyadh, Kingdom of Saudi Arabia were reviewed. We identified 2 main groups of patients with the diagnosis of AA.

Extraskeletal osteosarcoma, telangiectatic variant arising from the small bowel mesentery.

Extraskeletal osteosarcoma (EOS) is a highly aggressive and rare malignant soft tissue tumor, characterized by the production of neoplastic osseous tissue without attachment to the bone or periosteum. It rarely involves the visceral organs. Only 3 cases of mesenteric EOS have been reported in English literature.

Cholecystectomy without intraoperative cholangiogram in gallstone pancreatitis.

Objective: To determine the long term outcome of cholecystectomy without intraoperative cholangiogram (IOC) in patients recovering from acute gallstone pancreatitis with normal preoperative liver function tests and imaging.

Methods: The medical records of all patients who underwent cholecystectomy without IOC for gallstone pancreatitis at King Saud Medical City, Riyadh, Saudi Arabia between January 2005 and December 2009 were studied retrospectively. Patients with severe pancreatitis and those who had preoperative endoscopic retrograde cholangio-pancreatography (ERCP) were excluded from the study.

Abdominal wall abscess following laparoscopic cholecystectomy: an unusual late complication of lost gallstones.

Laparoscopic cholecystectomy (LC) is associated with a significant risk of gallbladder perforation with spillage of bile and stones into the peritoneal cavity. The retrieval of the spilled stones is not always possible by laparoscopic technique. Majority of these cases do not have any problem in future but sometimes the lost stones lead to serious complications.

Operative management of liver trauma. A 10-year experience in Riyadh, Saudi Arabia.

Objective: To analyze our experience and the outcome of operative management of liver trauma, and to suggest ways to improve the management of such patients.

Methods: This retrospective study was conducted on patients admitted with liver trauma to King Saud Medical Complex, Riyadh, Kingdom of Saudi Arabia between January 1997 and December 2006. Only patients who underwent operative management were included in this study.

Mirizzi syndrome: ten years experience from a teaching hospital in Riyadh.

Objective: Mirizzi syndrome (MS) is an uncommon presentation of cholelithiasis. This study aims to find the incidence and analyze the outcome of management of this condition at Riyadh Medical Complex (RMC) with particular reference to diagnostic methods and outcome of surgical treatment.

Methods: Retrospective study on 17 consecutive patients of MS diagnosed and managed at RMC over ten year period.

Initial factors predicting rebleeding and death in bleeding peptic ulcer disease.

Objective: Bleeding peptic ulcer constitutes approximately half of the cases admitted with upper gastrointestinal bleeding. Although the bleeding episode stops spontaneously in most of them, rebleeding occurs in as much as 10-30% of them and has a mortality rate of 5-10%. In this study, we have evaluated the possible significant predictors associated with this adverse outcome.

Outcome of nonoperative management of blunt liver trauma.

Objective: To evaluate our experience with the management of blunt liver trauma at Riyadh Central Hospital, Kingdom of Saudi Arabia.

Methods: The hospital records of 68 patients treated for blunt liver trauma at Riyadh Medical Complex over a 5-year period (1997 through to 2002) were reviewed retrospectively. Patients who were hemodynamically unstable or had peritonitis were treated by urgent laparotomy (operative group).

Management of foot lesions in 310 diabetics.

Full text is available as a scanned copy of the original print version.