Appendicitis is probably the single most common clinical problem encountered in pediatric surgery.
There are roughly 60,000 appendectomies done every year in the United States. Approximately 1/3 are ruptured, and it is estimated that appendicitis accounts for 100 deaths each year.
Since medieval times, the presence of RLQ pain and a palpable mass was usually a harbinger of death.
The disease was known as “paseo iliaca”, and was felt to be secondary to inflammation of the cecum.
In 1886, the Harvard pathologist, Reginald Fitz first coined the term “appendicitis” in his classic paper. This paper is probably the single most consequential event in the history of the disease.
Reginald Fitz is shown
Reginald Fitz studied at Harvard University, where he received his doctorate in 1868. Following a prolonged stay in Vienna, Berlin, and Paris, he settled in Boston, teaching pathological anatomy and general pathology at the Harvard Medical School, from 1873 as assistant professor, professor from 1879 to 1892. His most important works concern the appendicitis and acute pancreatitis. In 1886 he demonstrated the pathology of veriform appendix, and termed the disease appendicitis. Fitz described three forms of acute pancreatitis, and made the earliest suggestion that disseminated fat necrosis is the result of a pathologic process in the pancreas. His most famous paper was - “Perforating inflammation of the vermiform appendix, with special reference to its early diagnosis and treatment”, published in Transactions of the Association of American Physicians, Philadelphia, 1886, 1: 107-144. It is a conclusive demonstration of the pathology and symptoms of disease of the vermiform appendix. Fitz invented the term &quot;appendicitis&quot;. His paper, which records 25 cases collected by himself, convinced physicians of the need to remove the appendix immediately if threatening symptoms did not subside within 24 hours.
Charles McBurney was a surgeon who pioneered the diagnostics and operative treatment of appendicitis.
After graduating from Harvard in 1866, McBurney went to New York and obtained his M.D. from the College of Physicians and Surgeons in 1870. He then spent two years in Europe for further study in Berlin, London, Paris, and Vienna. Following his return to the United States in 1873 he commenced practice in New York, gaining appointment as an assistant demonstrator in anatomy at his alma mater, the College of Physicians and Surgeons. In 1888 was appointed the surgeon-in-chief at the Roosevelt Hospital, where most of his clinical work, including his famous studies on appendicitis was completed. He rapidly made his hospital one of the centers of surgical excellence of its day. McBurney’s classic report on early operative intervention in cases of appendicitis was presented before the New York Surgical Society in 1889. In it he described the area of greatest abdominal pain in this disease process, now known as McBurney’s point. Five years later, he set forth in another paper the incision that he used in cases of appendicitis, now called McBurney’s incision. He published numerous papers and was a keen hunter and fisherman. He died of a coronary thrombosis while on a hunting trip.
“ The seat of greatest pain, determined by the pressure of one finger, has been very exactly between an inch and a half and two inches from the anterior spinous process of the ilium on a straight line drawn from that process to the umbilicus”. from * C. McBurney: “Experience with early operative interference in cases of disease of the vermiform appendix.” McBurney also advocated operation before perforation occurred.
In 1887, TG Morton of Philadelphia performed the first successful operation for rupture of the appendix, and such operations soon became commonplace.
The etiology of most cases of appendicitis is felt to be obstruction of the lumen --- bacterial overgrowth and stasis----edema ---- venous infarction ---- ischemia---gangrene and necrosis---perforation.
Sometimes (10 -15%), a fecolith is responsible for obstruction of the appendix. Lymphoid hyperplasia may also obstruct the lumen. Other, less common causes of obstruction include carcinoid tumors, enterobius vermicularis (pinworm), and ascaris lumbriocoides. Measles, with multinucleated (Warthin-Finkeldy) giant cells in the lymphoid tissue can also be responsible for obstruction.
There are 5 clinicopathologic stages of appendicitis: these are not necessarily always distinct.
Simple - focal appendicitis. Appendix is normal or has only mild hyperemia and edema
Suppurative - there is usually demonstrable obstruction. Appendix is edematous, petechiae are visible, and there are sheets of fibrinopurulent exudate. The omentum and adjacent bowel may have begun to wall the process off.
Gangrenous - magnified findings above. Areas of gangrene also appear in the wall of the appendix. The peritoneal fluid may appear thinly purulent.
Ruptured - usually this occurs first at the antimesenteric border, often adjacent to an obstructing fecolith. Localization, occasionally with bowel obstruction, is evident.
Abscessed - this is usually in the right lower quadrant, lateral to the cecum, retrocecal, or subcecal and pelvic.
Appendicitis is an infectious disease whose treatment is surgical.
Numerous studies have demonstrated the uselessness of intraoperative cultures in perforated or simple appendicitis. It is easy to accurately guess what organisms will be present, and cover them with appropriate antibiotic therapy. If infectious complications develop, the flora may change, and repeat fluid/blood cultures will be necessary anyway.
The bacterial flora of appendicitis reflects the normal colonic flora - the predominant organism is B frag, followed by E coli. The peritoneal fluid is usually culture negative in the early stages of the disease: even in advanced appendicitis, B frag is not usually found, primarily because of difficulty in culturing the organism. From a microbiologic standpoint, ruptured and gangrenous appendicitis is similar.
The commonality of appendicitis may make the diagnosis quite difficult in those with an atypical presentation. Common things occur commonly Variations are frequent. 2/3 rds of appendices are retrocecal, retrocolic, or hang over the pelvic brim. Diarrhea may be due to extraluminal rectal irritation, urinary sx due to bladder irritation, or the appendix may be in an unusual location (eg LUQ w malrotation).
Overall, an accurate diagnosis, usually based on the history and physical exam, should be made in about 90% of children. The single most important take-home message of this talk is that it is far more important to avoid missing appendicitis than to take out a normal appendix.
The predominant symptom of appendicitis is pain. Pain is usually periumbilical at the onset (referred, 10th thoracic dermatome due to distention of the appendix and carried via the afferent sympathetic nerves thru the celiac ganglion). Pain is gradual in onset, and steady. A shift in location occurs as the referred pain gives way to local peritoneal irritation. The shift is to McBurney’s point. Movement then exacerbates the pain. Anorexia, nausea, and vomiting are common. Vomiting almost invariably follows the onset of the pain. Vomiting preceding the pain usually favors gastroenteritis.
It is often helpful to have the child use one finger to indicate the maximal point of discomfort. Rovsing’s sign (pain in RLQ with pressure over the opposite side of the abdomen) is very suggestive. Extension of the right hip or internal rotation and flexion may elicit pain as a sign of psoas irritation. Hyperesthesia over the site of pain is common (early sign). Heel tap may elicit RLQ pain. Niels Thorkild Rovsing was the most renowned Danish surgeon at the beginning of the twentieth century. He graduated in medicine from the University of Copenhagen in 1885 and obtained his medical doctorate in 1899. Following his internship/hospital service he was surgeon at the Louise-Børnehospital 1892-902, and from 1896 to 1900 surgeon-in-chief at the Red Cross Hospital. From 1899 he was professor of operative surgery at the University of Copenhagen. Initially his appointment did not provide him with hospital beds and he therefore commenced a private surgical nursing home to overcome this problem. In 1904 he was put in charge of the Frederiks Hospital as senior surgeon and, largely due to his advocation for better surgical accommodation, the Rigshospitalet was commenced in 1905 and opened in 1910. Primarily famous as an abdominal surgeon, he wrote extensively on diseases of the bladder and gall bladder and became internationally recognised. His work on abdominal surgery (1910-1918) was translated into German and English. He was described as an inspiring teacher. In 1908, together with Eilert A. Tscherning (1851-1919), he founded the Danish Surgical Society (Dansk Kirurgisk Selskap). A heart disease forced him to retire in 1925 and he died two years later.
Children with appendicitis usually appear ill. They minimize movement, often laying with the right hip flexed. Presence of distention, absent bowel sounds, or a mass are unreliable, particularly if not present. The cardinal physical finding in appendicitis is point tenderness. Even in the absence of any other finding, point tenderness over McBurney’s point is appendicitis until proven otherwise.
Lab - Most kids have a mild elevation of the wbc’s, with a left shift. A normal white count does not rule out appendicitis. UA - pyuria without bacturia may be due to appendicitis (pyuria is > 10-15 wbc/hpf in boys and 20-30 in girls).
Signs of a ruptured appendix include fever, leukocytosis, duration > 36 hrs, dehydration/acidosis, absent bowel sounds, generalized abdominal tenderness, Rovsing’s sign, diarrhea. The incidence of rupture in children < 6 years old is 50 %.
Often plain films are normal, and a normal AXR certainly does not exclude the diagnosis of appendicitis. Findings suggestive of appendicitis include 1) radiopaque fecolith (10%) 2) Right scoliosis, 3) extraluminal air, 4) increased free intraperitoneal fluid, 5) colonic cut-off sign at the hepatic flexure, soft tissue mass or abdominal wall edema. BE - filling of the appendix with barium is generally felt to exclude the diagnosis of appendicitis: however, in many patients with a normal appendix, the barium does not fill it. Positive findings include non-filling in association with cecal irregularity.
US - Accuracy depends on the radiologist. Identification of the appendix is possible about 70% of the time in experienced hands. Signs of appendicitis includes thickening (> 7 mm), incompressibility, pain with the probe over the appendix, local peritoneal fluid around the appendix, or an abscess. Again, a normal ultrasound, or particularly an ultrasound in which the appendix is not seen does not rule out the diagnosis. US is particularly helpful in adolescent females, in whom ovarian or tubal pathology is likely. CT – has become the de facto standard
This is an abdominal CT showing a fecolith in the appendix.
A recent radiologic study from MGH reviewed the status of appendiceal CT 5 years after its introduction: experience with 753 patients. This demononstrates several points: 1) Currently, almost everyone gets a CT if appendicitis is suspected 2) The CT is quite sensitive and accurate 3) The false neg laparotomy / laparoscopy rate decreases with CT Patient records from 2001 that included clinical or CT preoperative examination were analyzed, with follow-up through 2003. Of 753 patients, 663 (88%) had CT for suspected appendicitis. The incidence of appendicitis in the patients who underwent CT was 39.2%. The sensitivity and specificity of CT were 99% and 95%, respectively; and the percentage of equivocal CT interpretations was 3.3%.
The false-negative appendectomy rates were 3.0% and 5.6% for patients with and without CT, respectively (for all patients, p = 0.326; for female pediatric patients, p = 0.030). Five years ago, the negative appendectomy rate dropped from 20% to 7%, and it is now 3.0%. The incidence of appendicitis in patients who are examined on CT is stable compared with similar cohorts from prior investigations. Patients who do not undergo CT also have a low negative appendectomy rate, but this relatively small group is selected on the basis of a convincing clinical presentation. Female pediatric patients likely would have a lower negative appendectomy rate with greater use of CT.
The differential diagnosis is quite broad: Gastroenteritis is often distinguished by vomiting preceding pain, similar symptoms among other family members, and copious diarrhea. Constipation can cause pain, fever, vomiting, and leukocytosis. Often a history of constipation is lacking. The classic “shift” in pain location is absent, and there are no signs of peritoneal irritation. GU infection can cause similar sx Adenexal Disease in females is frequently mistaken for appendicitis
Mesenteric adenitis can occur in conjunction with URI, and may be indistinguishable from appendicitis. Meckel’s diverticulitis is rarely diagnosed preoperatively, and usually was felt to be appendicitis. PID demonstrates adenexal tenderness and cervical discharge. Pneumonia, esp. of the right lower lobe, can cause pain and muscle spasm in the abdomen, but tenderness should be absent. Often there is a significant lag time until radiographic changes are present. However, appendicitis and pneumonia can coexist, and an abscessed appendix can result in a subphrenic collection and a ‘sympathetic’ pleural reaction and effusion.
Antibiotics are given preoperatively if appendicitis is suspected. Therapy for ruptured or gangrenous appendicitis usually consists of “triple” antibiotics (AGC). Antibiotics can be stopped in 24 hours in cases of uncomplicated appendicitis. Duration of therapy for ruptured or gangrenous appendicitis is variable - our preference is to stop them when the child is clinically well, afebrile, and has no leukocytosis or left shift.
The treatment of appendicitis is early appendectomy (maybe). Error is best made in favor of appendectomy. Minimal preoperative preparation is necessary in most cases. In advanced disease, or sepsis, IVF re-hydration, correction of electrolytic disturbances, and broad-spectrum antibiotics are indicated. Usually operation can be carried out within 6 hours. In some cases, drainage of the abscess alone (percutaneously or operatively) may be an appropriate therapy after resuscitation, or medical management for those with perforation (at some centers).
Appendectomy can be performed via open or laparoscopic techniques. If inflammation is extremely severe, simple drainage may be necessary, with delayed appendectomy. If the cecum is extensively involved, resection of a small portion of the cecum with a tube cecostomy may rarely be necessary. Laparoscopic appendectomy can be performed. Certainly for perforated appendicitis, there appears to be a lower incidence of wound infection. Other benefits are questionable
Intraoperative irrigation is often used in appendicitis - adult studies would suggest little or no benefit. Leaving a drain in the peritoneal cavity is of no benefit, except for the rare circumstance of an isolated walled-off cavity In perforated appendicitis, wound closure with open appendectomy is controversial - delayed primary closure, primary closure, and secondary intention closure all have their advocates. Some close the skin over a drain or wick.
Some centers have reported large series of patients with perforated appendicitis managed with IV antibiotics. Even localized abscess collections are managed in this fashion, without percutaneous or surgical drainage. Failure to improve over 48 - 72 hours or worsening are indications for operation.
Most centers who use medical mgmt for perforated appendicitis do recommend interval appendectomy - some have questioned the need for this procedure, but the facts are not known and the medicolegal risks are significant. Certainly anyone with an appendicolith needs an interval appendectomy
Most postoperative complications are infectious, and the most common site of postoperative infection is the wound. This should be the first site investigated if the patient has unexplained fevers or fails to improve clinically.
Seen here are some of the more common and uncommon complications of appendicitis - all are increased with perforation.
Abscess formation is usually in the pelvis - rectal exam may demonstrate fullness. CT or US may be necessary. Overall, the incidence of major or minor complications is about 5%. Our incidence of abscess is about 14% in perforated appendicitis; < 1% in nonperforated appendicitis.
Wound infection is the most common source of morbidity in appendicitis. There is controversy concerning skin closure and the duration of antibiotic therapy. One study reported the results of a prospective protocol followed over 2 years with 420 children. The protocol was designed to determine whether the skin could be closed primarily in all patients undergoing appendectomy. Preoperatively all patients received triple antibiotics that were continued postoperatively for two doses if there was a normal appendix or simple acute appendicitis. Antibiotics were continued if the pt. remained febrile or had a white count greater than 10,000. No drains were used and the skin was closed primarily. The overall infectious complication rate was 1.0% (4/420). Among those with a normal appendix or simple acute appendicitis there were no infectious complications. Among those with gangrenous or perforated appendicitis, there were 1.7% wound infections (2/117) and 1.7% intraabdominal abscesses (2/117). J Pediatr Surg 1990 Nov;25(11):1113-6
Intestinal ileus is common for 5 -7 days after a ruptured appendix. Further prolongation may indicate abscess. Intestinal obstruction can be from abscess, adhesion, phlegmon, or volvulus around an adhesion. Most require reoperation. Appendiceal stump blow-out is a rare, sudden event. Drainage or tube cecostomy is the Rx. Sterility from scarring and obstruction of the fallopian tube is seen occasionally in girls after ruptured appendix.
The mortality rate is age dependent - > 2 yrs old : < 0.1% Infants: 10% Neonates: > 50%
1. Significant correlations were found between the use of ranitidine H2 blocker (P = .05) or diphenhydramine H1 blocker (P = .03) and the development of an abscess. Direct comparison found no differences in patient or operative variables in those given either medication compared with those receiving no doses. Abscess rate in those receiving neither medication (n = 41) was 10%. Those given only ranitidine (n = 24) or diphenhydramine (n = 17) had doubled abscess rates of 17% and 18%, respectively. Those given both medications (n = 16) had a quadrupled abscess rate of 44% (P = .03). Ranitidine or diphenhydramine given to patients with perforated appendicitis may increase the risk of postoperative abscess. Therefore, these medications should not be used empirically in this population. 2. Although initial laparoscopic appendectomy trends toward a requiring longer operative time, there seems to be no advantages between these strategies in terms of total hospitalization, recurrent abscess rate, or total charges. 3. In total, the reviewers were correct 72% of the time with an overall sensitivity of 62% and a specificity of 81%. The overall positive predictive value was 67%, and the negative predictive value was 77%. This study shows that in the absence of a well-formed abscess, the triage of patient care based on a preoperative diagnosis of perforation from CT may be imprudent and subject a portion of the population to an unnecessarily prolonged course of care. 4. At presentation, a positive correlation for abscess formation was identified with increasing age (P = .003), weight (P = .001), body mass index (P = .008), and diarrhea (P = .005). Operative time had no influence on abscess development. After operation, there was progressively increasing positive correlation between abscess and the maximum temperature each successive postoperative day. This relationship became significant at day 3. An increased white blood cell count on day 5 was highly predictive of abscess (P < .001). In children presenting with perforated appendicitis, increasing age, weight, and/or body mass index correlated with the development of a postoperative abscess. Diarrhea on presentation also poses an increased risk of abscess. Postoperatively, each successive day with a fever is incrementally more predictive of an abscess formation. 5. There were 292 patients treated for acute nonperforated appendicitis in the 2 years before the definition and 388 patients after the definition. There were 131 patients treated for perforated appendicitis before the definition and 161 after the definition was implemented. The abscess rate in those with perforated appendicitis increased from 14% to 18% after the definition was used. However, after the definition began to be used, the abscess rate for those patients treated as nonperforated decreased from 1.7% to 0.8%. Defining perforation as a hole in the appendix or a fecalith in the abdomen is effective in identifying the patients at risk for postoperative abscess formation. Application of these criteria would allow substantial reduction in therapy for patients with purulent or gangrenous appendicitis who do not possess the same abscess risk. These data outline the first evidence-based definition of perforation. 6. One hundred patients underwent laparoscopic appendectomy for perforated appendicitis. On presentation, there were no differences in sex distribution, days of symptoms, temperature, or leukocyte count. There was no difference in abscess rate or wound infections between groups. The CM group resulted in significantly less antibiotic charges then the AGC group. Once daily dosing with the 2-drug regimen (CM) offers a more efficient, cost-effective antibiotic management in children with perforated appendicitis without compromising infection control when compared to a traditional 3-drug regimen.
1st use of diagnostic imaging of intussusception via a Bismuth enema. (First published Xrays of intussusception)
1st Hydrostatic reduction with barium reported, with fluoro. A 1926 report noted 100 cases with successful reduction in 62% and only 1 death.
Dogmatic idiot - several report in the yrs before had 75% successful reduction rates with NO mortality.
1959 - air reduction first reported in China
Peristalsis propagates the intussusceptum distally Compression and angulation of the mesenteric vessels to the invaginated bowel leads to obstruction, ischemia, and eventual necrosis. Necrosis begins at the apex of the intussusceptum.
This is the approximate incidence of intussusception in the US. About 40 - 50% are between 3 - 9 mo, and more than 75% are < 2 yr old
Children with intussusception tend to get &quot;sick in the summer&quot;. Adenoviruses and to lesser extent rotovirus implicated in up to 50% of cases
&quot;Permanent&quot; means doesn't spontaneously resolve. Note that in one large study, 10% of cases that failed enema reduction had spontaneously reduced by the time of operation.
Incidentally, Peyer's Patches are on the antimesenteric side of the bowel until the distal ileum, where they become circumferential.
85% are Ileo colic and 10% are ileo ileo colic. 95% have NO pathologic lead point. (just lymphoid tissue).
Overall, 5% of intussusceptions have PLP, but this increases to 20% if > 2 yrs old.
PLPs are classified as focal (single lesions like Meckels and polyps) versus diffuse bowel wall thickenings (HSP, celiac, CF, HAEC). Postoperative intussusception accounts for 1% - 2% of cases
Key is that MOST recurrences are NOT associated with a PLP (Pathologic lead point).
Also, most were chronically ill, with weight loss and an abdominal mass. Most were > 4 yrs old.
Occurs after laparotomy as well as cardiac, thoracic, and orthopedic cases. Marked by gradual onset of early bowel obstruction. Most common after retroperitoneal tumors and extensive dissections (pullthrough). US is diagnostic.
May be related to intestinal atresia: 13 reported cases among premature infants with ileal atresia and stenosis noted in the area of intussusception in 6 of the 13 cases.
Previously healthy infant with intermittent, crampy abdominal pain, drawing up of legs. Attacks range 5 to 30 minutes - calm vs lethargic between attacks. Vomiting frequent “ current jelly” stools 1/5 have hx viral illness and may have diarrhea or resp sx. Clinical diagnostic accuracy is about 50%
Theoretically, gas throughout the entire bowel and colon completely outlined by stool effectively R/O intussusception via plain films. False + and - make this less helpful. AF levels are present as often as they are absent in intussusception.
“ target sign” - most specific and sensitive sign is a soft tissue mass with 2 concentric circles of fat density, absence of cecal gas and stool, loss of visualization of tip of liver: paucity of bowel gas, particularly RLQ
BE is rarely used.
BE after successful reduction
Single best study “ target sign” - on transverse section. pseudokidney - on longitudinal section
“ target sign” - on transverse section pseudokidney - on longitudinal section
Thickness of outer hypoechoic rim of the intussusception, intraperitoneal fluid, fluid present within the intussusception; color Doppler flow studies all have yielded equivocal results
About 3% of HSP pts get intussusception. Steroids may relieve symptoms but not relieve the intussusception. Are they (steroids) preventative - > unknown?
Absolute contraindications: peritonitis, perforation, profound shock Relative contraindications: chronic and neonatal intussusceptions, history >48 hours, small bowel obstruction on plain x-ray, and children > 2 years
In 1980’s, pneumatic reduction with air reported in China with high success rates in 6000 patients. Procedure of choice in recent years Advantages include: quicker, less messy, easier to perform, and therefore delivers less radiation , less patient discomfort
Delayed repeat enema: 1. < 36 hrs of sx 2. T < 38 C 3. Pulse < 150, 4. Intuss moves closer to IC valve on 1st attempt 5. Pt becomes asx 6. Interval of 2 - 4 hrs between attempts. (60% success on repeat in one report)
Successful air enema reduction.
Latter study - no perfs in last 3,000 cases (new low pressure pump). J Z Guo, X Y Ma, and Q H Zhou, “Results of air pressure enema reduction of intussusception: 6,396 cases in 13 years,” Journal of Pediatric Surgery 21, no. 12 (December 1986): 1201-1203. Intussusception is the most common surgical emergency of childhood in China. Over the past 10 years, the incidence of intussusception has steadily increased world-wide, as well as in China. For example, 279 cases were treated in the Shanghai Children's Hospital in 1974, while 615 were treated in 1984. Twelve cases were treated in a course of a single night during 1985. Over the past 13 years, for which we have good records, 6,396 cases of intussusception were treated at the Shanghai Children's Hospital. Males outnumber females by a ratio of 2 to 1. In 3,872 cases seen over the past 6 years, 35.1% were under 6 months of age, 65.9% less than 1 year of age, and 88.4% less than 2 years of age.
Right sided transverse incision above or below umbilicus Gentle, steady pressure at the apex of the intussusception Resection and primary anastamosis of necrotic areas, ischemic areas, or intussuscepted areas that cannot be reduced
Postoperative adhesive small bowel obstruction 3% - 6%
We conducted a retrospective review of all of the patients who had a radiographically irreducible intussusception treated via the laparoscopic approach at a single institution from 1998 to 2008. Means are expressed +/- standard deviation. A total of 22 patients were identified, with an average age of 2.9 +/- 3.0 years. Average length of stay was 2.67 +/- 1.5 days (median, 2). Sixteen (73%) of the 22 patients were male. There were 19 ileocecal and 3 small bowel intussusceptions. Twenty patients (91%) were able to be managed entirely laparoscopically or via extension of the umbilical incision, while 2 necessitated conversion, using a right-lower quadrant incision. Nine patients had an extension of the umbilical incision; 7 of these underwent a bowel resection. Ten patients (46%) had a bowel resection, of which 5 were an ileocecectomy and 5 were segmental small bowel resection. There were a total of 9 patients with a pathologic lead point, 5 patients with lymphoid hyperplasia, and 4 with Meckel's diverticula. We conclude that laparoscopy is a reasonable approach to pediatric intussusception, even in the event when bowel resection is necessary.
St Peter SD, Sharp SW, Ostlie DJ. Influence of histamine receptor antagonists on the outcome of perforated appendicitis: analysis from a prospective trial. Arch Surg. 2010 Feb;145(2):143-6.
St Peter SD, Aguayo P, Fraser JD, Keckler SJ, Sharp SW, Leys CM, Murphy JP, Snyder CL, Sharp RJ, Andrews WS, Holcomb GW 3rd, Ostlie DJ. Initial laparoscopic appendectomy versus initial nonoperative management and interval appendectomy for perforated appendicitis with abscess: a prospective, randomized trial. J Pediatr Surg. 2010 Jan;45(1):236-40.
Fraser JD, Aguayo P, Sharp SW, Snyder CL, Rivard DC, Cully BE, Sharp RJ, Ostlie DJ, St Peter SD. Accuracy of computed tomography in predicting appendiceal perforation. J Pediatr Surg. 2010 Jan;45(1):231-4; discussion 234-4.
Fraser JD, Aguayo P, Sharp SW, Snyder CL, Holcomb GW 3rd, Ostlie DJ, St Peter SD. Physiologic predictors of postoperative abscess in children with perforated appendicitis: Subset analysis from a prospective randomized trial. Surgery. [Epub ahead of print]
St Peter SD, Sharp SW, Holcomb GW 3rd, Ostlie DJ. An evidence-based definition for perforated appendicitis derived from a prospective randomized trial. J Pediatr Surg. 2008 Dec;43(12):2242-5.
St Peter SD, Tsao K, Spilde TL, Holcomb GW 3rd, Sharp SW, Murphy JP, Snyder CL, Sharp RJ, Andrews WS, Ostlie DJ. Single daily dosing ceftriaxone and metronidazole vs standard triple antibiotic regimen for perforated appendicitis in children: a prospective randomized trial. J Pediatr Surg. 2008 Jun;43(6):981-5.