#52 – Pyloric Stenosis



  • 2-4 per 1000 live births worldwide and 20 per 10,000 live births in the US
  • Higher male to female ratio (4-6:1)
  • Higher incidence (1.5x) in first-born children
  • Highest incidence in caucasian infants
  • Less common in infants of older mothers

Risk Factors and Etiology

The exact mechanisms and etiologies are unclear, but it is hypothesized that it is multifactorial and is a result of both genetic predisposition and environmental triggers.

  • Environmental Factors
    • Maternal smoking (up to 2x increased risk)
    • Bottle feeding
      • Bottle feeding during first 4 months increased risk by 4x
        • Didn’t delineate formula vs breastmilk
  • Genetic Factors
    • Reports of familial aggregation, but there is no clear research association
    • Apolipoprotein A1 (APOA1) gene cluster
      • Hypothesized low plasma cholesterol at birth and increased risk
  • Macrolide Antibiotics
    • Increased risk if given to infants < 2 weeks old
      • Treatment/prophylaxis for pertussis
    • Association with maternal use during first two weeks of life
  • Icteropyloric syndrome
    • Unconjugated hyperbilirubinemia
      • Most commonly from early Gilbert’s Syndrome

History and Physical Examination

  • Class presentation for PANCE
    • < 6 week old with post-prandial, non-bilious projectile vomiting around 10 minutes after cessation of feeding
    • Ravenous feeder even after vomiting
  • May be emaciated and/or dehydrated
    • Though we are diagnosing earlier and infants tend to be healthier
  • Palpable mass in the epigastrium (50-90%)
    • This is also less commonly seen due to healthier infants and ease of obtaining radiologic students
      • 73% in the 1970s to only 30% now
    • Ideally, immediately after vomiting and while the infant is calm
  • Other important assessments
    • Height/weight
    • Mucous membranes and skin turgor
    • Skin and sclerae
    • Genitalia
      • Ambiguous genitalia raises suspicion for congenital adrenal hyperplasia and adrenal crisis

Diagnostic Studies

  • Laboratory
    • Hypochloremic metabolic alkalosis
      • 88% PPV if pH > 7.45, chloride < 98, and base excess > +3
    • Assess for dehydration
      • BUN/creatinine > 20:1
    • Liver Function Tests
      • Bilirubin breakdown, AST/ALT, GGT, and ALP
  • Radiography
    • Ultrasound is the test of choice
      • Accuracy is operator dependent, but can reach > 95% sensitivity/specificity
      • “Target” sign on transverse view
      • Normal Measurements (vary with age and used together)
        • Pyloric Muscle Thickness
          • < 3mm
        • Pyloric Muscle Length
          • < 14mm
        • Pyloric Channel Length
          • < 16mm
Target Sign on Transverse View
  • Fluoroscopic Upper Gastrointestinal Series
    • Used if ultrasound is nondiagnostic
    • Classic findings :
      • “string” sign from an elongated pyloric canal
      • “double-track” sign from two thin tracks of barium along the pyloric canal created by compressed pyloric mucosa
      • “beak”sign from a tapered point at the pyloric ending
      • “shoulder” sign from a prepyloric bulge of barium
1) Beak Sign, 2) String Sign, 3) Double Track Sign, 4) Shoulder Sign

Differential Diagnosis

Although pyloric stenosis has a classic presentation, you must entertain the other important causes of vomiting in infancy.


  • Definitive management is surgery
  • Timing of surgery depends on the clinical status of the infant
    • If healthy, surgery can be performed on the day of diagnosis
    • If ill, then resuscitation and feeding need to be performed to limit perioperative complications.
  • Technique
    • Ramstedt Pyloromyotomy
      • Longitudinal incision of the pylorus with blunt dissection down to the submucosa
  • Open vs Laparoscopic
    • No difference in operating time, time to full feeding, or length of stay
    • Laparoscopic had lower incidence of emesis and better pain control, but higher incidence of incomplete surgical release
  • Postoperative Management
    • Feeding
      • Resumed within a few hours after surgery
      • Regurgitation is common, but should not delay/stop feedings
    • Breathing
      • Monitor for apnea at least for 24 hours
    • Complications
      • Mucosal perforation (rare)


  • Surgery is curative in the majority of patients
  • Once normal feeds occur, only routine pediatric care and follow-up is needed
  • Reflux is common and managed conservatively

The Cottage Physician (1893)


  1. Kapoor R, Kancherla V, Cao Y, et al. Prevalence and descriptive epidemiology of infantile hypertrophic pyloric stenosis in the United States: A multistate, population-based retrospective study, 1999-2010. Birth defects research. 2019; 111(3):159-169. [pubmed]
  2. To T, Wajja A, Wales PW, Langer JC. Population demographic indicators associated with incidence of pyloric stenosis. Archives of pediatrics & adolescent medicine. 2005; 159(6):520-5. [pubmed]
  3. Krogh C, Fischer TK, Skotte L, et al. Familial aggregation and heritability of pyloric stenosis. JAMA. 2010; 303(23):2393-9. [pubmed]
  4. Krogh C, Gørtz S, Wohlfahrt J, Biggar RJ, Melbye M, Fischer TK. Pre- and perinatal risk factors for pyloric stenosis and their influence on the male predominance. American journal of epidemiology. 2012; 176(1):24-31. [pubmed]
  5. Svenningsson A, Svensson T, Akre O, Nordenskjöld A. Maternal and pregnancy characteristics and risk of infantile hypertrophic pyloric stenosis. Journal of pediatric surgery. 2014; 49(8):1226-31. [pubmed]
  6. Zhu J, Zhu T, Lin Z, Qu Y, Mu D. Perinatal risk factors for infantile hypertrophic pyloric stenosis: A meta-analysis. Journal of pediatric surgery. 2017; 52(9):1389-1397. [pubmed]
  7. McAteer JP, Ledbetter DJ, Goldin AB. Role of bottle feeding in the etiology of hypertrophic pyloric stenosis. JAMA pediatrics. 2013; 167(12):1143-9. [pubmed]
  8. Sørensen HT, Nørgård B, Pedersen L, Larsen H, Johnsen SP. Maternal smoking and risk of hypertrophic infantile pyloric stenosis: 10 year population based cohort study. BMJ (Clinical research ed.). 2002; 325(7371):1011-2. [pubmed]
  9. Feenstra B, Geller F, Carstensen L, et al. Plasma lipids, genetic variants near APOA1, and the risk of infantile hypertrophic pyloric stenosis. JAMA. 2013; 310(7):714-21. [pubmed]
  10. Eberly MD, Eide MB, Thompson JL, Nylund CM. Azithromycin in early infancy and pyloric stenosis. Pediatrics. 2015; 135(3):483-8. [pubmed]
  11. Honein MA, Paulozzi LJ, Himelright IM, et al. Infantile hypertrophic pyloric stenosis after pertussis prophylaxis with erythromcyin: a case review and cohort study. Lancet (London, England). ; 354(9196):2101-5. [pubmed]
  12. Lund M, Pasternak B, Davidsen RB, et al. Use of macrolides in mother and child and risk of infantile hypertrophic pyloric stenosis: nationwide cohort study. BMJ (Clinical research ed.). 2014; 348:g1908. [pubmed]
  13. Touloukian RJ, Higgins E. The spectrum of serum electrolytes in hypertrophic pyloric stenosis. Journal of pediatric surgery. 1983; 18(4):394-7. [pubmed]
  14. Bakal U, Sarac M, Aydin M, Tartar T, Kazez A. Recent changes in the features of hypertrophic pyloric stenosis. Pediatrics international : official journal of the Japan Pediatric Society. 2016; 58(5):369-71. [pubmed]
  15. Sivitz AB, Tejani C, Cohen SG. Evaluation of hypertrophic pyloric stenosis by pediatric emergency physician sonography. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 2013; 20(7):646-51. [pubmed]
  16. Niedzielski J, Kobielski A, Sokal J, Krakós M. Accuracy of sonographic criteria in the decision for surgical treatment in infantile hypertrophic pyloric stenosis. Archives of medical science : AMS. 2011; 7(3):508-11. [pubmed]
  17. Hernanz-Schulman M. Pyloric stenosis: role of imaging. Pediatric radiology. 2009; 39 Suppl 2:S134-9. [pubmed]
  18. Said M, Shaul DB, Fujimoto M, Radner G, Sydorak RM, Applebaum H. Ultrasound measurements in hypertrophic pyloric stenosis: don’t let the numbers fool you. The Permanente journal. 2012; 16(3):25-7. [pubmed]
  19. Iqbal CW, Rivard DC, Mortellaro VE, Sharp SW, St Peter SD. Evaluation of ultrasonographic parameters in the diagnosis of pyloric stenosis relative to patient age and size. Journal of pediatric surgery. 2012; 47(8):1542-7. [pubmed]
  20. St Peter SD, Holcomb GW, Calkins CM, et al. Open versus laparoscopic pyloromyotomy for pyloric stenosis: a prospective, randomized trial. Annals of surgery. 2006; 244(3):363-70. [pubmed]
  21. Hall NJ, Pacilli M, Eaton S, et al. Recovery after open versus laparoscopic pyloromyotomy for pyloric stenosis: a double-blind multicentre randomised controlled trial. Lancet (London, England). 2009; 373(9661):390-8. [pubmed]


Fascia of Scarpa

Other Known Aliasesdeep fascia of abdominal wall, stratum membranosum

DefinitionThe membranous layer of the superficial abdominal fascia that is deep to the fascia of Camper and superficial to the external oblique muscle.

Clinical SignificanceThis is one of the classic nine abdominal layers you cut through when performing open abdominal procedures and is a favorite pimp question among general surgeons.

HistoryNamed after Antonio Scarpa (1752-1832), who was an Italian anatomist and professor and received his medical doctorate at the University of Padua at the age of 18. He held numerous professorships of anatomy throughout Italy. His Traité pratique des hernia of 1812 was the authoritative work on hernias and from which his eponym is derived. Unfortunately, his political views and ruthless nature as a nobleman tarnished his reputation (almost irrevocably) after his death from kidney stones in 1832. Statues were defaced and destroyed and, in an act of morbid homage, his head from removed from his cadaver and sent to the Institute of Anatomy in Bologna for exhibition. In fact, it is still on exhibition at the University History Museum in Pavia, Italy.


  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Up To Date. www.uptodate.com

PAINE #PANCE Pearl – Surgery


This is a classic surgery pimp question for 1st year clinical students:

What the nine (9) layers of the anterior abdominal wall you cut through during an open abdominal procedure?


There are nine layers to the anterior abdominal wall and they are (from superficial to deep):

  1. Skin
  2. Camper’s fascia
  3. Scarpa’s fascia
  4. External oblique
  5. Internal oblique
  6. Transversus abdominis
  7. Tranasversalis fascia
  8. Preperitoneal fat
  9. Peritoneum


Fascia of Camper

Other Known Aliasessuperficial fascia of abdominal wall

DefinitionThe fatty outer layer of the superficial abdominal fascia and is continuous with the superficial fascia of the thigh.

Clinical SignificanceThis is one of the classic nine abdominal layers you cut through when performing open abdominal procedures and is a favorite pimp question among general surgeons.

HistoryNamed after Petrus Camper (1722-1789), who was a Dutch physician and anatomist, and received both a PhD and medical doctorate from the University of Leiden in 1746 at the age of 24. He spent many years as a traveling doctor throughout Europe. He subsequently held positions as professorships of surgery and philosophy at Franeker University and University of Amsterdam. He was a scholar and gentleman throughout his illustrious career and made tremendous strides in the fields of human and veterinary medicine, anthropology, and the arts.

Camper’s Anatomy Lesson (1758)


  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Up To Date. www.uptodate.com


Billroth I and II Operation

Other Known Aliasesgastroduodenostomy and gastrojejunostomy

DefinitionIn a Billroth I procedure, the distal stomach is removed and the distal stomach is connected with a end-to-end anastomosis to the duodenum. In a Billroth II procedure, the distal stomach is removed and connected with a side-to-side anastomosis to the jejunum.

Clinical SignificanceBoth of these procedures are used in distal gastric pathologies, including gastric cancer, recurrent peptic ulcer disease, large duodenal perforations, bleeding gastric ulcer, gastrointestinal stromal tumors, or corrosive stricture of the stomach. A Billroth I is generally preferred as it has less complications and restores normal GI continuity. A Billroth II is used to prevent undue tension on the anastomosis secondary to scarring.

HistoryNamed after Christian Albert Theodor Billroth (1829-1894), who was an Austrian surgeon and generally regarded as the founding father of modern abdominal surgery. He received his medical doctorate from the Frederick William University of Berlin in 1852. His medical career was almost completely abandoned due to his love of music and was a close friend of Johannes Brahms. He became the Chair of Clinical Surgery at the University of Zurich in 1860. He was well known as a charismatic and infectious instructor, attracting students throughout Germany. It was at this post that he published is classic textbook Die allgemeine chirurgische Pathologie und Therapie (General Surgical Pathology and Therapy) in 1863. He was directly responsible for several landmark historical surgeries including:

  • 1872 – first to perform an esophagectomy
  • 1873 – first to perform an laryngectomy
  • 1876 – first to perform rectal cancer excision
  • 1881 – first to perform antrectomy for gastric cancer

Other notable mentions for Dr. Billroth is his early adoption of the “white coat” and surgical cleanliness. He also was an advocate for prolonged surgical apprenticeships following completion of medical studies and was the precursor to William Halsted’s pioneering residency program at Johns Hopkins


  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Up To Date. www.uptodate.com
  6. Kazi RA, Peter RE. Christian Albert Theodor Billroth: master of surgery. Journal of postgraduate medicine. ; 50(1):82-3. [pubmed]

#49 – Hernias



  • Approximately 5 million people in the US
    • Majority are groin hernias
      • 2/3rd are on the right
  • 1/3rd of all repairs are ventral hernias
    • 1/3rd of these are incisional and 2/3rd are primary


The abdominal wall is made up of multiple, overlapping muscles and connective tissue whose main purpose is to contain and protect the intra-abdominal organs, while also serving as accessary muscles of respiration and facilitating axial movements.  The bony boundaries of the abdominal cavity are:

  • Xiphoid process superiorly and costal margins laterally
    • With diaphragm separating the abdominal cavity from thoracic cavity
  • Pubic symphysis inferiorly and iliac crests laterally
    • With the inguinal ligament connecting them

The lateral rectus abdominis muscles also fuse midline to form the linea alba and laterally to the connect with the confluence of the external oblique, internal oblique, and transverse abdominis muscles.

Weakness at any of these junctions (either anatomic or iatrogenic) can allow herniation of abdominal contents through this defect.  Pascal’s principle states that any pressure generated within a closed system (abdominal cavity) is transmitted equally to the walls of the system.

Classification and Definitions of Hernia Types

  • Ventral
    • Anterior
    • Epigastric
      • Occur between Xiphoid and umbilicus
      • Generally < 1cm in size
    • Umbilical
      • Most common overall and more common in women
    • Spigelian
      • Occurs through aponeurosis of the transverse abdominal muscle bounded by the linea semilunaris and lateral edge of the rectus muscle medially
    • Incisional
  • Groin
    • Inguinal
      • Indirect (most common overall)
        • Through the deep ring and inguinal canal
    • Femoral (more common in women)
      • Through the femoral ring into the femoral canal posterior and inferior to the inguinal ligament

Signs and Symptoms

  • History
    • Can be asymptomatic if small
    • Most patients will feel a “bulge” and have varying degree of pain associated with this
    • Coughing, straining, or Valsalva worsen the pain or increase the size
    • Groin Hernias
      • Heaviness or dull discomfort in the groin
      • Pain improves when lying supine
    • Systemic symptoms (fever, nausea/vomiting, abdominal pain, bloating) should raise your suspicion of an incarcerated or strangulated hernia
  • Physical Examination
    • Abdominal wall should be examined with the patient standing and lying supine
      • Have patient bear down or cough to accentuate while palpating in the anatomic region
    • Examine for previous surgical incisions
    • Palpate around the umbilicus
    • In men, invaginate the scrotal skin to reach the inguinal canal
    • Femoral hernias most commonly occur medial to the femoral pulse
    • If any erythema or induration is visible, or if the bulge is tender to palpation, this should raise your suspicion of an incarcerated or strangulated hernia


Most hernias in non-obese patients should be diagnosed by careful and thorough history and physical examination.  In others, radiographic investigation must be performed.

  • Computed Tomography
    • Gold standard to identify sac, contents, and surrounding edema or inflammation
  • Ultrasound
    • Can be very helpful if the diagnosis of groin hernia is unclear

Surgical Repair

Most hernias will require surgical repair at some point.  The decision for operative management comes down to risk of future complications, size, and symptom tolerance.  Patients with strangulation or incarceration MUST emergent/urgent surgical repair to limit the risk of bowel ischemia.

Surgeon preference and patient considerations dictate laparoscopic vs open hernia repair.

Preclusion to laparoscopic repair include:

  • Prior surgery involving the preperitoneal space
  • Complicated hernias
  • Ascites
  • Inability to tolerate general anesthesia

Surgical Techniques for Groin Hernias

  • ††Open
    • Tension-free mesh repairsPrimary tissue approximation non-mesh repair
  • Laparoscopic (both require mesh)
    • Totally extraperitoneal (TEP) repair
      • Avoids the peritoneal cavity by developing a plane of dissection in the preperitoneal space
        • Landmarks for entry to the preperitoneal space are:
          • Median umbilical ligament
          • Hernia defect
      • This space is entered by establishing a plane between the posterior surface of the rectus muscle and posterior rectus sheath and peritoneum
  • Transabdominal preperitoneal patch (TAPP) repair
    • Advantage is that all three groin hernia types are well visualized and in close proximity to each other

Surgical Repair for Ventral Hernias

  • Goals for repair
    • Prevent hernia recurrence
    • Low rate of surgical site infection
    • Provide dynamic muscle support
    • Provide a repair with physiologic tension
    • Prevent eventration or abdominal wall bulging
    • Incorporate the abdominal wall
  • < 1cm
    • Open repair with or without mesh directly over the defect
  • 1-10cm
    • Can be repaired either open or laparoscopic with mesh
      • 1-4cm midline ventral – open
      • 1-4cm incisional – open or laparoscopic
      • 4-10cm all types – laparoscopic
  • > 10cm
    • Unlikely to be closed laparoscopic and require open

Cottage Physician


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  2. Earle DB, McLellan JA. Repair of umbilical and epigastric hernias. The Surgical clinics of North America. 2013; 93(5):1057-89. [pubmed]
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  7. Murphy KP, O’Connor OJ, Maher MM. Adult abdominal hernias. AJR. American journal of roentgenology. 2014; 202(6):W506-11. [pubmed]
  8. Bedewi MA, El-Sharkawy MS, Al Boukai AA, Al-Nakshabandi N. Prevalence of adult paraumbilical hernia. Assessment by high-resolution sonography: a hospital-based study. Hernia : the journal of hernias and abdominal wall surgery. 2012; 16(1):59-62. [pubmed]
  9. Earle D, Roth JS, Saber A, et al. SAGES guidelines for laparoscopic ventral hernia repair. Surgical endoscopy. 2016; 30(8):3163-83. [pubmed]
  10. Sailes FC, Walls J, Guelig D, et al. Synthetic and biological mesh in component separation: a 10-year single institution review. Annals of plastic surgery. 2010; 64(5):696-8. [pubmed]
  11. Shell DH, de la Torre J, Andrades P, Vasconez LO. Open repair of ventral incisional hernias. The Surgical clinics of North America. 2008; 88(1):61-83, viii. [pubmed]
  12. Luijendijk RW, Hop WC, van den Tol MP, et al. A comparison of suture repair with mesh repair for incisional hernia. The New England journal of medicine. 2000; 343(6):392-8. [pubmed]
  13. DiBello JN, Moore JH. Sliding myofascial flap of the rectus abdominus muscles for the closure of recurrent ventral hernias. Plastic and reconstructive surgery. 1996; 98(3):464-9. [pubmed]