TITLE: Zenker’s Diverticulum
SOURCE: Grand Rounds Presentation,
DATE: May 28, 2010
MEDICAL STUDENT: Jill D’Souza, Class of 2011
FACULTY PHYSICIAN: Michael Underbrink, MD
DISCUSSANT: Michael Underbrink, MD
SERIES EDITOR: Francis B. Quinn, Jr., MD
ARCHIVIST: Melinda Stoner Quinn, MSICS
"This
material was prepared by resident physicians in partial fulfillment of
educational requirements established for the Postgraduate Training Program =
of
the UTMB Department of Otolaryngology/Head and Neck Surgery and was not
intended for clinical use in its present form. It was prepared for the purp=
ose
of stimulating group discussion in a conference setting. No warrantie,
either express or implied, are made with respect=
to
its accuracy, completeness, or timeliness. The material does not necessarily
reflect the current or past opinions of members of the UTMB faculty and sho=
uld
not be used for purposes of diagnosis or treatment without consulting appro=
priate
literature sources and informed professional opinion."
Introduction:
Zenker’s Diverticulum is a rare cause of dysphagia worldwide. = Surgical management of Zenker’s diverticulum is complex and requires the exper= tise of an experienced Otolaryngologist.
History:
Descriptions of hypopharyngeal diverticula have appeared in scientific literature for over two hundred years. They were fir= st described by Abraham Ludlow, in 1764, and described by several pathologists= in the following years. The seminal work on hypopharyngeal diverticula was car= ried out in collaboration between German pathologists Albert von Zenker and Hugo von Ziemssen in 1867, titled Krankheiten des Oesoph= agus, or Diseases of the Esophagus.
Surgical repair of Zenker’s Diverticulum w= as rarely attempted prior to mid-20th century due to high rates of morbidity and mortality. The first successful divertic= ulectomy was carried out by von Bergman in 1892, though surgical techniques had been postulated for decades. In 1909 Goldmann introd= uced a two-stage surgical technique which caused fistulizatio= n and rejection of the diverticulum. The late 193= 0s saw the refinement of technique into a single-stage procedure, and in 1951 the cricopharyngeal myotomy technique was introduced by Kaplan. Diverticulopexy with myotomy was first used in 1966 by Belsey and was successful in decreasing operative tim= e and hospital stays. The importance of myotomy in the treatment of Zenker’s Diverticulum was highlighted by studies done by Einars= son and Hallen, which showed the decrease in recurr= ence rate when myotomy is performed. Endoscopic techn= iques were first attempted in the early 1900s, but the mortality rate was conside= red unacceptably high, and the procedures were abandoned. In the 1960s, Dohlman and Mattson introduced diathermy as a method = to divide the common wall of the diverticula and the esophagus. Von Overbeek continued this endoscopic trend and over the= next thirty years improved on the Dohlman technique,= using the CO2 laser rather than diathermy. In 1993, Collard et al introduced what= is now widely considered to be the standard surgical approach to a moderate-si= zed diverticulum, the endoscopic stapling technique.
Anatomy and Physiology:
Zenker’s diverticulum is a posterior esoph= ageal outpouching of mucosa through an area of weakness between the inferior constrictor muscle and the cricopharyngeus. The neck of the diverticulum is proximal to the cricopharyngeus. This area of weakness, also known as Killian’s triagle, or Killian’s dehiscence, is the most common location for a Zenker’s diverticulum. Rarely, two other areas can be involved: Killian-Jamieson area, between the oblique and transverse fibers = of the cricopharyngeus muscle, and the Laimer triangle, between the cricopharyngeus and the superior esophageal wall circular muscles.
Zenker’s Diverticulum is found almost exclusively in humans, which is thought to be due to the fact that the human larynx is larger and located more caudally in humans than in other animals.= The caudal location results in an oblique orientation of the constrictor muscle= s, and consequently areas of weakness develop through which esophageal mucosa = can herniate.
The incidence of Zenker’s Diverticulum is
estimated at 2 per 100,000, with highest rates of diagnosis in the seventh =
and
eighth decades of life. Risk factors for development of Zenker’s
Diverticulum include increasing age, male gender, presence of hiatal hernia,
and/or gastroesophageal reflux disorder (GERD). Up to 94% of patients with
pharyngeal pouches have concurrent hiatal hernias or GERD. This link is also
supported by the fact that Zenker’s diverticulum is extremely rare in
Asia and
Zenker’s diverticulum is a pulsion-type diverticulum, the result of herniation of the esophageal mucosa and submuco= sa through the area of natural weakness. As such, it is a false diverticulum, meaning it does not involve the muscularis layer. Evagination of the cricopharyngeal sphincter is believed to occur secondary to chronic increased pressure over esophageal areas of weakness. = The presences of abnormal esophageal motility, esophageal shortening, and upper esophageal sphincter dysfunction have all been implicated in the pathogenes= is of Zenker’s Diverticulum. Data supporting these hypotheses have been obtained through manometry studies, and consensus opinion is that occlusive mechanisms are the most important. Uncoordinated swallo= wing, allied with impaired relaxation and spasm of cricopharyngeal muscle leads t= o an increase in pressure in distal esophagus, so that its wall herniates through the point of maximal weakness – Killian’s triangle.
The mucosal outpouching of a Zenker’s diverticulum can be visualized via a barium swallow study. Two-thirds of Zenker’s diverticula protrude directly in the midline, and the remain= ing preferentially protrude to the left. This is lik= ely secondary to the more lateral location of the carotid artery on the left, and subsequent esophageal curvature. Contrast radiography can confirm the diagnosis. Two commonly used classification sch= emes are Brombart (1980) and Morton and Bartley (1993). Other classification sch= emes include vertebral body measurements, and simple radiologic appearance, but categories are becoming increasingly complex and incorporate elements from several of the classic methods of classification.
Clinically, Zenker’s diverticulum presents= as a progressive dysphagia. Intially, patient can describe minor throat irritati= on, foreign body sensation, and coughing. Symptoms worsen as the diverticulum enlarges, and pouch becomes large enough to contain food, sputum or even medications. Patients can complain of food regurgitation several hours afte= r a meal, and typically describe weight loss. Cachexia and malnutrition can dev= elop with Zenker’s Diverticulum, particularly in the elderly who develop a “fear of eating” secondary to choking spells. The most common complication of Zenker’s Diverticulum is aspiration pneumonia, which occurs in up to 30% of patients. Other complications include compression of= the trachea and esophageal obstruction with large diverticula, as well as ulceration secondary to retained aspirin. Development of squamous cell carc= inoma of the diverticulum can occur in 0.3-0.5% of patients.
Indications:
Due to the high risk of complications if untreat= ed, surgical intervention is the mainstay of Zenker’s Diverticulum therap= y.
Standard treatment is excision of diverticulum and cricopharyngeal (CP) myotomy, including upper 3cm of posterior esophageal wall. Size of the diverticulum determines which procedure to carry out. If diverticulum is less than two centimeters, a CP myotomy alone is sufficient. If diverticulum is between t= hree and six centimeters, endoscopic or open procedure must be used. When the diverticulum exceeds 6cm, an open approach is generally considered a more favorable procedure.
Cricoph= aryngeal myotomy must always be performed in the course of a Zenker’s diverticulum repair, as without it there is an unacceptably high rate of recurrence.
Procedures:
·<=
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style=3D'font:7.0pt "Times New Roman"'> =
Cricopharyngeal myotomy
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style=3D'font:7.0pt "Times New Roman"'> =
Endoscopic techniques:
o =
Endoscopic staple
diverticulostomy
o =
CO2 laser
o =
electrocautery
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External techniques:
o =
Cricopharyngeal myotomy=
with diverticulectomy
o =
Cricopharyngeal myotomy=
with diverticulopexy
Surgical Preparation
For all procedures, patient should undergo a pre-operative evaluation to determine cardiac function and hemodynamic stat= us. Evaluation of diverticulum should guide the choice of procedure as described above.
Cricopharyngeal myotomy
External cricopharyngeal myotomy can be performed under local or general anesthesia. Endotracheal intubation provides distention of the cervical esophagus to aid in visualization of the muscle. Left-sided anterior cervical incision is made = over the cricoid cartilage, and subplatysmal skin flaps are retracted to expose superior and inferior border of cricopharyngeus muscle. Anterior border of sternocleidomastoid is identified and then retracted posteriorly to reveal the carotid sheath. The omohyoid may be sectioned to provide greater exposure= of the surgical target. The larynx is be rotated to the right, bringing forward the distended cervical esophagus. Fibers of the cricopharyngeus are visualized = with a magnifying loupe, and then sequentially incised until t= he underlying mucosa appears. The myotomy is often four to fi= ve centimeters in length to ensure complete release of the muscle.
Wound should then be irrigated, drain placed,
Endoscopic staple diverticulostomy
Endoscopic staple diverticulostomy is performed = under general endotracheal intubation, using a modifi= ed laryngoscope to expose common wall between lumen of esophagus and diverticulum. A magnified view of the procedure can be obtained by using a rigid 0- or 30- degree telescope connected to a camera. With a suturing device, retraction sutures are placed on the lateral aspect= s of the common wall. The common wall is then positioned between the blades of t= he stapler, and divided. The retraction sutures are cut and removed. By dividing the common wall, an internal cricopharyngeal myotomy is performed, creating a single lumen without removal of the pouch. The telescope is then used to carefully inspect the esophagus and incision area to evaluate for surgical debris such as staples. Patient can be discharged on same day as surgery if no post-operative complications arise in the three or four hours following the procedure.
CO2 laser
Transoral tissue bri= dge dissection with CO2 laser is carried out under general anesthesia with endotracheal intubation. For optimal exposure of the = common bridge, a Weerda laryngoscope is inserted transorally and opened, tightening the muscular septu= m. After evaluation of the tissue bridge, debris is suctioned from the diverticulum. Microscope with manipulator and CO2 las= er are focused on the common bridge at a working distance of 400mm. Laser dissecti= on begins in the center of the tissue bridge, causing a split of the muscle fi= bers and allowing increased visualization of the esophagus. The tissue bridge is dissected to the base of the diverticulum,
Electrocautery
Esophageal diverticulotomy<= /span> with electrocautery is carried out under general anesthesia with endotracheal intubation. A modi= fied, slotted, Holinger 9mm x 30 cm esophagoscope is inserted to trap the common wall, where the upper lip of the instrument = will be placed in the esophagus and the lower lip in the di= verticulum. The common wall is thus isolated and then divided using insulated electrocautery and laparoscopy scissors. The common w= all is cauterized until it thins near the base of the diverti= culum, and incision is continued to ensure division of the cricopharyngeus muscle also.
Cricopharyngeal myotomy with diverticulectomy
Cricopharyngeal myotomy with diverticulectomy is
carried out under general anesthesia with endotracheal=
intubation. An anterior cervical incision is made over cricoids cartilage, =
or,
alternatively, along anterior border of sternocleidomastoid muscle. Dissect=
ion
of soft tissue underlying the incision follows, with medial retraction of
trachea, strap muscles and thyroid gland, while the sternocleidomastoid mus=
cle
is retracted laterally. This allows exposure of the di=
verticulum
and the cricopharyngeus muscle. Once identified, the cricopharyngeus is
divided, and the diverticulum is excised. The d=
efect
can be closed by purse-string suture, or by stapler.
Cricopharyngeal myotomy with diverticulopexy
Following the same operative technique as the
Potential Complications of Surgical Management of Zenker’s Diverticulum
Esophageal perforation
The esophagus lacks a serosal layer, and thus is= at higher risk of rupture or perforation. Patient should be allowed nothing by mouth after midnight and broad-spectrum antibiotics given. Gastrografin study should be obtained to evaluate level of possible perforation. Perfora= tion of cervical esophagus can be managed with close observation or with explora= tion and drainage procedure. Thoracic esophagus perforation requires early exploration. If symptoms reso= lve in 7-10 days, one repeats the gastrografin to eval= uate resolution of perforation, and antibiotics can be discontinued if there is = no evidence of infection. Close monitoring of vital signs and white blood cell count is essential.
Mediastinitis
Once esophagus is ruptured, retained gastric con= tent, saliva, bile, and other substance may enter mediastinum. Patient will prese= nt with severe dyspnea, chest pain and fever, Diagnosis can be confirmed with = CXR or CT scan which will show the characteristic mediastinal widening. Aggress= ive therapy is required: mortality rate is between 14-40%. Treatment consists of aggressive drainage and IV antibiotics, as well as close monitoring by a thoracic surgery team.
Laryngeal nerve damage
The recurrent laryngeal nerve courses below the
inferior constrictor muscle to innervate the laryngeal muscles (with the
exception of the cricothyroid.) This muscle is
innervated by the superior laryngeal nerve). Damage sustained during diverticulum surgery is usually unilateral, and so pa=
tient
may present with post-operative hoarseness but without airway impairment. <=
/p>
Discussion by Dr. Michael Under= brink – Zenker’s Div= erticulum 2010-05-26
Dr. Underbrink: That was an excellent presentation. It was very tho= rough and complete and it gave us a lot of information about the pathogenesis and treatment options for Zenker’s diverticulum. = I think the important things to realize is patient selection for the type of surgery that you have. As far= as grading the Zenker’s by one of the classification scales noting that in small diverticula= , are you going to be able to treat these by myotomy alone? This can be done endoscopically although most people prefer an open technique for that. The size = of the diverticulum as was presented being between thr= ee and six centimeters is a good size for the approach endosc= opically which also reduces the complication rate.&= nbsp; So that in some patients, case selection is impo= rtant. And inb= etween that you’ll be watching for the most common complications postoperati= vely which we all know. The most devastating would be mediastinitis. Good talk. Thank you.
Dr. Francis B. Quinn: How do you = find the opening of the diverticulum endoscopically?
Dr. Underbrink: The answer is that using the instrumentation we have in our operating room, the Wer= dacope opens in two directions, both distally and proximally, as you enter under t= he cricoid cartilage just opening a small bit the poster= ior tine will find the diverticulum, and the anterior tine if opened correctly = will find the esophagus and you’re looking for a double bubble on your exam and when you see that you’re advancing slowly being careful not to perforate a large diverticulum with your poster= ior tine. That might be one of the complications of placement. Y= ou want to make sure that the cricopharyngeus musc= le or the bridge of mucosa over the muscle easily visible so you can place sutures and retract that so you can make the incision.
References: