Journal Logo

M2E Too! Mellick's Multimedia EduBlog by Larry Mellick, MD

​The M2E Too! blog presents important clinical pearls using multimedia. By its name, M2E Too! acknowledges that it is one of many emergency medicine blogs, but we hope this will serve as a creative commons for emergency physicians.​

Please share your thoughts about Dr. Mellick's posts.

Comment


Thursday, January 2, 2020

I'll admit it. I hate the cricothyrotomy. It's not because I haven't done one for a decade or because it is a complicated procedure. Or because I dread the thought of leaving a permanent cosmetic defect on someone's neck. Or because it is a procedure performed as a last resort under extreme time pressure on a hypoxic patient who will almost assuredly die if you fail.

It has something to do with the word failed, as in failed airway. That surgical airway is there because the physician could not gain effective control of the patient's airway using all of the other airway tools at his disposal. We all understand that failure is part of the reason we have to perform a surgical airway. And we know that all of our colleagues will be Monday morning quarterbacks debating whether a surgical airway was necessary.

I remember during a residency rotation in the SICU listening to derisive comments about the emergency department when an admission arrived with a cricothyrotomy. My worst nightmare played out. Someone even referred to the bloody bandage on the patient's neck as the "red badge of shame."

There are, however, actual occasions where it remains necessary and appropriate to perform a cricothyroidotomy because of facial trauma or extreme swelling. Depending on the type of hospital, it occurs about one percent of the time, lower now most likely due to the availability of video laryngoscopes and increased sophistication of alternative airway options.

We can break the cricothyroidotomy options into small-caliber cannula (i.e., IV angiocatheter), large-caliber cannulas that can be inserted percutaneously through the cricothyroid membrane, and open surgical cricothyrotomy. The percutaneous techniques have a role, but the relatively narrow diameter and the increased length appear to require increased force for ventilation. (Br J Anaesth. 2011;106[1]:57; http://bit.ly/35rUOei.) This blog, however, will focus on the surgical techniques, which have at least three variations: the standard, rapid four-step, and the scalpel-finger-bougie (also known as the three-step method).

The bougie-aided cricothyroidotomy combines the Seldinger and the rapid four-step techniques. (StatPearls [Internet]. Jan. 14, 2019; http://bit.ly/2KKKxCc.) The standard technique is reliable, but the rapid four-step technique can be performed in about one-third of the time. (Ann Emerg Med. 1998;32[4]:442.) The primary differences between the standard and rapid techniques are:

ProcedureStandard TechniqueRapid Four-Step Technique
Patient ApproachRight sideLeft side
Membrane IdentificationIdentification of the cricothyroid membrane (CTM) by blunt dissectionIdentification of the cricothyroid membrane by palpation
Incision DirectionMidline vertical, 4 cmTransverse (vertical incision if one can't palpate the CTM)
Incision TechniqueShort horizontal stab incision in the lower part of the cricothyroid membraneHorizontal stab incision through the skin and cricothyroid membrane with the scalpel
Ostomy DilatationDilatation of the ostomy with curved hemostats or Trousseau dilatorNone
InstrumentsScalpel with a no. 11 blade, Trousseau dilator, hemostats, tracheal hook, no. 6 Shiley tracheostomy tubeScalpel with a no. 20 blade, tracheal hook, no. 6 Shiley tracheostomy tube (or ET tube)
Tracheal Hook

Stabilization of the larynx with a tracheal hook at the cephalad side of the incision, i.e., the inferior edge of the thyroid cartilage

 

Stabilization of the larynx with the tracheal hook at the inferior aspect of the ostomy (on the cricoid cartilage), providing caudal traction

 Sliding a gum elastic bougie through the incision using a finger to guide it inferiorly into the trachea before using the bougie Seldinger-style to guide the ET tube or the Shiley into the trachea can be done with either technique. It is, however, more commonly described as a variation of the rapid four-step technique.

Even though a surgical cricothyrotomy is not a difficult procedure, it has a number of little-known challenges that can lead to unwanted complications. A number of papers using ultrasound and CT as gold standards tell us that our ability to identify the location of the cricoid cartilage and cricothyroid membrane accurately is much worse than we realized. (Am J Emerg Med. 2018;36[11]:2078; Can J Anaesth. 2016;63[7]:807.) The physical examination for identifying the cricothyroid membrane is not always easy, but add in obesity or an anatomic abnormality, and the difficulty multiplies. Not accurately locating the cricothyroid membrane results in unwanted complications such as inadvertent tracheotomies involving the cricoid ring and first tracheal ring, transection of the cricoid ring, or even an incision very high, at the hyoid bone.

A number of examination tricks can be used, such as measuring four-finger breadths from the sternal notch, going one finger breadth inferior to the laryngeal prominence, or using skin creases, which have not been shown to be sensitive. Even though ultrasound is effective in identifying the cricothyroid membrane, it consumes too much time during an airway emergency, so ultrasound isn't recommended during a cricothyroidotomy performed at the end of a failed airway algorithm.

Some authors recommend that ultrasound localization of the cricothyroid membrane be part of the checklist for an anticipated difficult airway. (Anesthesiol Clin. 2015;33[2]:357.) Another little-known challenge is that the cricothyroid membrane is often much smaller than previously reported. One study using CT measurements reported that the mean height is about 8 mm in men and 6 mm in women. This measurement does not dictate actual capacity, but it should be considered during the procedure. That study recommended having tracheal tubes of various sizes ready and available to accommodate potentially small cricothyroid membrane heights. (Anaesthesia. 2017;72[8]:987; http://bit.ly/2DfsdwN.)

The other challenge of this procedure is that the posterior tracheal wall may be injured more frequently than we realize during the procedure. (Ann Emerg Med. 1998;32[4]:442.) It seems to happen a little more frequently with some of the percutaneous cricothyroidotomy kits, but also occurs with open surgical techniques. (Br J Anaesth. 2011;106[1]:57, http://bit.ly/35rUOei; Anesthesiol Clin. 2015;33[2]:357.) Some recommend placing a digit low on the scalpel blade during the incision of the membrane to maintain better control of blade depth.

The lifesaving cricothyroidotomy procedure is a mandatory skill for emergency physicians. Understanding the potential pitfalls of this procedure and the different techniques available to avoid them is critical.

mellick-cricothyrotomy-rapid four-step technique-video-Edward Panacek.jpg

Watch a video of the bougie and rapid four-step technique by Edward Panacek, MD, one of the first to describe this technique.

Monday, December 2, 2019

I have been seeing a lot of second disease and fifth disease—it's that time of year. School is back in session, and winter is just around the corner.

The rash-numbering system for these diseases is now a historical footnote, but fifth disease is still commonly used by physicians to refer to erythema infectiosum, a parvovirus. I suspect that this system was created as a memory device for similar names and the obscure Latin terms used for these diseases. Erythema infectiosum is also easy to confuse with the many other erythema rashes such as erythema migrans, erythema marginatum, erythema toxicum, and erythema multiforme. When you throw in exanthem subitum, the Latin name for roseola, one can understand why fifth disease remains part of our medical nomenclature.

NameOther namesEtiology
FirstRubeola, measles, hard measlesMeasles virus
SecondScarlet fever, scarlatinaStreptococcus pyogenes
ThirdRubella, German measles, three-day measlesRubella virus
FourthFilatov-Dukes' disease, staphylococcal scalded skin syndromeNonexistent or Staphylococcus aureus strains that make exfoliative toxin
FifthErythema infectiosumErythrovirus (parvovirus) B19
SixthExanthem subitem (roseola infantum)Human herpes virus 6b or human herpes virus 7

We are seeing a resurgence of this deadly disease because of resistance to vaccinations. Before the vaccine, measles was responsible for five to eight million deaths worldwide each year. It has a reputation of being one of the most contagious human pathogens. About 10 days after exposure, fever and malaise signal the onset of the illness. The 3 Cs—cough, coryza, and conjunctivitis—follow.

Gradual worsening of symptoms follows, including a steadily rising fever of up to 105.8°F. The conjunctivitis causes edema of the eyelids and remarkable lacrimation, and photophobia is common. Two days before the exanthem, characteristic Koplik spots develop in the mouth. There is a reason this viral infection was called hard measles. It lasts about 14 days.

Like rubella, the three-day version of measles, the initial confluence of the discrete, irregular macules begins behind the ears, on the neck, and at the hairline. The rash covers the face and quickly descends to the trunk and extremities. It is distinctive enough that we coined the phrase measly rash. In past years when we saw more measles cases, the rash on the face was a valuable clue to differentiating this virus from other morbilliform rashes. Parental concern about measles is frequently a driving force for bringing children with rashes to the emergency department.

Patients with untreated or unrecognized strep throat often present to the ED with a scarlet fever rash, or second disease. The rash is caused by the pyrogenic exotoxins SPE A, B, C, and F, and is distinctive and described as goose flesh on sunburn or a sandpaper-like rash. Circumoral pallor is commonly described as part of the scarlet fever rash, as are lipstick red lips. We recently had a patient with a positive rapid strep test and prominent red lips, which can also be engorged. The fine sandpapery rash seen in Caucasian children often presents as a much coarser rash in African-American children.

mellick-pediatric rashes-positive strep test-red lips.jpg

Watch this video of a patient with a positive rapid strep test and prominent red lips, which can also be engorged.

Rubella is the kinder, gentler measles virus, and is also called three-day measles. Up to half of infected patients are asymptomatic. The virus is a member of the Togaviridae family, and was first isolated in 1962. The incubation period is 14 to 21 days, and primary replication occurs in the nasopharynx. The clinical course begins with adenopathy of the postauricular, occipital, and posterior cervical nodes. These can be slightly painful. The rash persists for two to three days and has a variable appearance. Initially, one sees small pink and irregular macules on the face.

The rash subsequently spreads rapidly within 24 hours to the neck, trunk, arms, and finally legs. By day two, the lesions may coalesce and become maculopapular and eventually scarlatiniform. Unlike rubeola, rubella does not present with the three Cs. Unfortunately, this virus is not as kind to fetuses and can have catastrophic complications when a mother is infected early in her pregnancy. The congenital rubella syndrome includes hearing impairment, cardiac defects, cataracts, and developmental delay.

There is no longer a fourth disease. Originally called Filatov-Dukes' disease, no one currently knows exactly what disease Drs. Filatov and Dukes were describing. It has been postulated that fourth disease was actually staphylococcal or streptococcal scalded skin syndrome.

Erythema infectiosum is caused by the parvovirus B19 virus, and was first described in 1975. The child's cheeks characteristically have a slapped face appearance and a soft pink, lacy, reticulated rash over the trunk and extremities. Incubation occurs over four to 14 days, but can be as long as three weeks. The prodromal illness is nonspecific, and includes fever, malaise, headache, myalgia, nausea, and rhinorrhea. This prodromal period begins five to seven days after initial infection and coincides with the onset of viremia.

mellick-pediatric rashes-fifth disease-slapped face appearance.JPG

Watch this video of a child with fifth disease who presented with a slapped face appearance and a rash over his extremities.

Replication of the virus occurs in human erythroid progenitor cells of the bone marrow and blood. This can lead to cytotoxicity and inhibition of erythropoiesis. Like rubella, it can cause problems for fetuses. Rarely, miscarriages, severe fetal anemia, and hydrops fetalis are complications of utero infections. Unfortunately, once the rash develops, the child is usually no longer infectious, but the week before has been spreading the virus in school and day care. The viral infection can present more often in adults with a localized, well-demarcated purpuric eruption with painful edema and numerous small confluent petechiae on the hands and feet. This presentation is appropriately called the gloves-and-socks syndrome, and it usually resolves in one to three weeks.

The viral disease roseola or exanthem subitum was first described in 1910, and occurs in children 6 to 36 months old. Roseola is caused by the human herpes viruses VI and less commonly VII. It has two variants, HHV 6a and 6b. The latter is most commonly associated with roseola presentations. This condition is characterized by high fevers (105°F-106°F) that defervesces after three to five days. In fact, the magnitude of the fever has frequently prompted a partial septic workup and initiation of empiric antibiotics.

The timing of the rash and empiric antibiotics has caused many a child to be wrongly diagnosed as allergic to antibiotics. An erythematous macular or maculopapular rash appears simultaneously with defervescence of the fever. The discrete maculopapular soft pink lesions start on the trunk and spread centrifugally to the extremities, neck, and face. The rash is gone in a day or two.

Myringitis or viral inflammation of the tympanic membranes also occurs during this infection. Febrile seizures are the most commonly associated complication. HHV6 was associated in one study with a third of the febrile seizures. Bulging fontanelles can also occur with this viral infection, which may result in LPs to assess for meningitis.

The names rubella, rubeola, and roseola can be confusing to those learning medicine, and erythema infectiosum and exanthem subitum are nondescript enough to make them difficult to remember. We shouldn't return to the disease-numbering system used in the past century, but I understand why someone felt the need to come up with this memory system.

Friday, November 1, 2019

It never ceases to amaze me how nothing is ever as simple as it seems. Breath-holding spells are just the latest of the simple and common medical conditions that turn out to be much more complex than ever imagined.

It all started during a recent shift in the pediatric emergency department with a toddler who presented after a breath-holding episode. He fell after losing his balance on a trampoline.

It started as a classic pallid breath-holding spell that then manifested as crying out, stopping breathing, and rapidly losing consciousness. He then had a CNS anoxic event. The unconscious child clenched his fists and arched his back into opisthotonos posturing. The whole event played out over 30 to 45 seconds, and he was pale afterwards.

This is where the story became more interesting. It appeared he had had a simple breath-holding episode, but he was actually in a subset of children who have a more severe cardioinhibitory presentation of this syndrome. An ambulatory cardiac monitoring device had previously documented that he rapidly proceeded through vasovagal-induced bradycardia that progressed to asystole.

He was being treated with a mineralocorticoid, fludrocortisone. The patient's cardiologist said he may ultimately need a pacemaker and his medical record listed cardioinhibitory malignant vasovagal syndrome. Even though this nomenclature is not widely used, it adequately defines what is going on with this patient.

I researched this patient's condition and began to see breath-holding spells from a new perspective. These spells are toddler vasovagal events. The 0.1 percent to 4.6 percent of children who are prone to these episodes are genetically and physiologically different. (Curr Pediatr Rev. 2019;15[1]:22; http://bit.ly/2mGkSSo.) The best clues to etiopathogenesis that we currently have suggest that contributing factors are autonomic nervous system dysregulation, vagally-mediated cardiac inhibition, delayed myelination of the brainstem, and iron deficiency.

Children with breath-holding spells ultimately grow out of this condition around age 5 when something physiologically changes during the maturation process to make them less vulnerable to these dramatic and frightening vasovagal events. As we know, a spectrum of different presentations exists in adults with vasovagal syncope. Tilt table testing divides them into four types (Open Cardiovasc Med J. 2016;10:179; http://bit.ly/2m9FsKL):

  • Type 1: A drop in blood pressure followed by a modest drop in heart rate
  • Type 2A: Cardioinhibition without asystole
  • Type 2B: Cardioinhibition with asystole (longer than three seconds), and blood pressure decrease occurs simultaneously with or before the fall in heart rate
  • Type 3: Vasodepressor decrease in blood pressure, but heart rate within 10 percent of its peak

In other words, bradycardia, hypotension, both, or less commonly, asystole will be present at the onset of syncope. Children with cyanotic and pallid breath-holding spells appear to have sufficient variations in presentation, and one is forced to assume that different physiologic events with similar results are occurring. Only the most severe, usually pallid, breath-holding spells have documented asystole.

Every child having a breath-holding spell ultimately loses consciousness from hypoperfusion or a loss of blood flow to the brain, and anoxic posturing or seizures follow not infrequently. The only explanation for the loss of consciousness and signs and symptoms of anoxia can be sudden hypotension, severe bradycardia, or transient asystole.

Cyanotic, pallid, and mixed breath-holding presentations are poorly explained variations in appearance during periods of cerebral anoxia. In other words, breath-holding spells result from vagal hyperresponsiveness following a sudden, unexpected, unpleasant stimulus and resulting in a drop in blood pressure or a cardioinhibitory event such as bradycardia or asystole. Further evidence supporting vagal hyperresponsiveness is that piracetam, atropine, glycopyrrolate, and theophylline have had a therapeutic benefit. (Medicine [Baltimore]. 2015;94[28]:e1150; http://bit.ly/2nP8hwq.)

mellick breath-holding spells-pediatric-vasovagal event-video.JPG

Watch a video of Dr. Mellick talking to the mother of a toddler who had a breath-holding spell and a vasovagal event.

Tuesday, October 1, 2019

The back story of pyloric stenosis is fascinating. It is a relatively minor surgical condition today, but the disease had a mortality of 100 percent before 1904, when only five operative cases were known to have been performed in the United States. The dying process was slow and painful, and parents watched their infants slowly starve to death.

The pyloromyotomy procedure currently used to treat pyloric stenosis was introduced by Conrad Ramstedt, MD, in 1911 at the Children's Hospital of Munster, and is still called the Ramstedt procedure. Before surgical management was introduced for this gastric outlet obstruction, multiple unsuccessful medical therapies had been attempted, including treating infants with bromides, antipyrine, cocaine, novocain, belladonna, and atropine.

Attempts at emergency fluid resuscitation involved administration subcutaneously or as nutrient enemas, the rectal administration of nutrient-containing solutions. Only atropine has shown evidence of success. In fact, a 2005 article by Kawahara, et al., described 45 of 52 patients (86.5%) whose projectile-vomiting was stopped using intravenous atropine. (J Pediatr Surg. 2005;40[12]:1848.) Treatment with intravenous atropine (median of 7 days) was followed by oral atropine (median of 44 days). The median hospital stay was 13 days (6-36 days). The relevance of a medical therapy to us in emergency medicine is the patient who is clinically unstable or has contraindications for immediate surgery. Atropine is also relevant to physicians working in austere environments.

Pyloric stenosis occurs in two to four per 1000 live births. Pathologic hypertrophy and hyperplasia of the circular and longitudinal muscular layers of the pylorus occur, resulting in marked narrowing of the gastric antrum. These changes result in gastric outlet obstruction. It is more common in male infants, and the reported male-to-female ratio is 4:1 to 6:1. It is also more common in preterm infants, and most commonly occurs in firstborn children (30-40%).

Symptoms typically begin between 3 and 5 weeks of age and are rare after 12 weeks. Infants will eventually demonstrate nonbilious, forceful vomiting after every feeding and then be ready to eat again almost immediately. (See the video of an infant with a classic presentation of pyloric stenosis.) The patient will have metabolic abnormalities if the vomiting is prolonged and the presentation late. Hypochloremic and hypokalemic metabolic alkalosis is now less common, but these abnormalities historically contributed to the death of infants. Hyperperistalsis may be observed traveling left to right across the abdomen just before emesis.

mellick-pediatric-pyloric stenosis-hyperperistalsis.JPG

Watch a video of an infant with pyloric stenosis experiencing hyperperistalsis.

An olive may also be palpated in the right upper quadrant. An association between early postnatal macrolide use and pyloric stenosis is well documented. (Ital J Pediatr. 2019;45[1]:20; http://bit.ly/2zQvocH; Eur J Pediatr. 2019;178[3]:301.) Ultrasound is highly sensitive and specific for pyloric stenosis. A target should be seen on the transverse view, and measurement criteria are as follows:

  • Pyloric muscle thickness (PMT): 3-4 mm
  • Pyloric muscle length (PML): 15-19 mm
  • Pyloric diameter (PD): 10-14 mm

An important caveat is that normal values do vary with the size and gestational maturity of the infant. (Pediatr Surg Int. 2009;25[12]:1053; http://bit.ly/2PTwG1A.) Consequently, the small or young infant will typically not meet these measurement standards. Ultrasound is highly sensitive and specific in making the diagnosis, but a barium swallow may sometimes be required. Specific signs seen during barium examination include the shoulder sign, antral nipple sign, cervix sign, and target sign. Because the basics of pyloric stenosis are well known to most emergency physicians, this blog will focus on a few things you may not know or have not seen.

Early-Onset Pyloric Stenosis

Most cases of PS occur after 3 weeks of age, but approximately five percent of infants present much earlier. Early presentation of pyloric stenosis appears to be associated with a positive family history. Strongly consider the diagnosis if a vomiting infant outside the typical age range presents with a family history of PS.

mellick-recently diagnosed pediatric patient with pyloric stenosis.JPG

Watch a video of an infant with a family history of pyloric stenosis who was diagnosed at 13 days of age.

Again, the clinical takeaway is that sonographic diagnostic measurements specific to this age exist and can prevent delays in diagnosis and treatment.

 mellick-pediatric patient weight loss from pyloric stenosis.JPG

Watch a video of an infant with weight loss from pyloric stenosis.

Finding the Olive

The olive is the hypertrophied pylorus that is potentially palpable at the lateral edge of the rectus abdominis muscle in the right upper quadrant. This may be a relatively subjective examination, and requires a calm infant who is not crying. Most clinicians rely on ultrasound to make the diagnosis, and a search for the olive is less commonly done, but some pearls are helpful for finding it.

  • Be sure the infant is calm. A sucrose-soaked pacifier may help relax the infant.
  • The olive is best palpated immediately after an episode of emesis because a distended antrum can obscure the examination. Gastric contents may need to be removed by a nasogastric tube.
  • Palpate for the olive in the right upper quadrant lateral to the abdominis rectus muscle.

Hypochloremic and Hypokalemic Metabolic Alkalosis

Severe prolonged vomiting results in the loss of hydrochloric acid from the stomach and in the kidneys retaining hydrogen ions in favor of potassium. The alkalosis is perpetuated by urinary losses of Na+ and HCO3 as part of the compensation for chloride losses. This derangement also occurs in vomiting adults with pyloric stenosis or gastric outlet obstruction.

Hyperbilirubinemia

Unconjugated hyperbilirubinemia is another lesser known laboratory abnormality seen in infants. The association has even been labeled as icteropyloric syndrome. The elevated bilirubin resolves after surgery. The clinical diagnosis of pyloric stenosis can be summarized as the three Ps: projectile vomiting, peristalsis, and a palpable olive.

Tuesday, September 3, 2019

Prepubertal boys who present to the emergency department with dysuria are uncommon. The adult with burning on urination is assumed to have a sexually transmitted disease, but of course that diagnosis should not be high on your list for boys.

In fact, infectious urethritis in children is quite uncommon unless there is premature sexual activity or sexual abuse by an adult. Unfortunately, a variety of noninfectious urethral pathologies may mimic infectious urethritis in children. A urinary tract infection in a prepubertal boy is an infectious cause of dysuria. Those infections, however, rarely present with the isolated symptom of burning on urination. There is often evidence of bladder irritability manifested by urgency and frequency. Self-inoculation associated with herpes labialis can also result in an HSV genital infection and painful urination.

We should consider noninfectious causes of dysuria when a urinary tract infection, balanoposthitis, a candida infection, or a sexually transmitted disease is not present. Noninfectious irritation of the urethra is most commonly caused by chemical exposures (bubble bath), local trauma, or meatal stenosis. Bubble bath is probably the most common cause of noninfectious dysuria in prepubertal boys. The therapeutic solution for this condition is to stop using bubble bath. See the video of a patient with burning on urination due to bubble bath use.

Local trauma is another possible etiology of dysuria. It may be self-induced by the prepubertal boy during self-exploration or masturbation. Meatal stenosis is a cause of noninfectious dysuria that is less commonly recognized. This condition occurs primarily in circumcised boys. The exposed penis can develop recurrent local inflammation around the urethral meatus, and scarring of the meatus with the development of a stricture can occur eventually.

These patients present with distinct signs and symptoms. Abnormalities of urination are the most common. The spraying or misdirection of the urine stream is also common and an important feature of the history. Pain at the beginning or end of urination has also been reported, as have blood spots on the underwear, burning at the meatus, straining on urination, and prolonged emptying of the bladder. Ultrasound may demonstrate thickening of the bladder. Treatment of this condition is meatotomy, where a few millimeters of the ventral lip of the meatus are divided. See the video of a patient with meatal stenosis below.

Dysfunctional voiding also mimics urinary tract infection and urethritis. This condition is more commonly seen by pediatric urologists and less commonly in the emergency department. It occurs primarily between the ages of 3 and 7, and symptoms include wetness, urinary tract infections, urgency, frequency, infrequency, constipation, and fecal incontinence. The precise pathophysiology is still unknown, but uninhibited bladder contractions, pelvic floor overactivity, or poorly learned voiding techniques may contribute. Upper urinary tract changes such as hydronephrosis and renal insufficiency can occur in severe cases. One therapeutic option is bladder retraining involving relaxation techniques and electromyographic biofeedback from the pelvic floor.

Dysuria in a prepubertal boy is uncommonly infectious once a urinary tract infection is ruled out. Instead, other conditions such as bubble bath urethritis, local trauma, or meatal stenosis should be considered.

mellick-prepubertal dysuria.JPG

Watch a video showing Dr. Mellick talking with the parents of two patients with meatal stenosis.