What is the true value of cricopharyngeal myotomy ?
M. Starlinger (Tubingen)
Despite a great variety of disease states that may be associated with oropharyngeal dysphagia, the common denominator is failure of the food bolus to be transferred from the pharynx into the tubular esophagus. This deficiency can best be demonstrated by cineradiographic studies. These show pharyngeal ballooning, prominent indentation by the cricopharyngeal muscle and occasionally aspiration of the contrast material into the trachea.
Manometry may show either failure of the upper esophageal sphincter to relax upon swallowing or failure of the relaxation to coordinate with pharyngeal contraction. While specific medical treatment directed against the underlying disease is successful in certain conditions associated with oropharyngeal dysfunction, such as hypo- or hyperthyroidism, Parkinson disease, myastenia gravis and inflammatory myopathies (dermatomyositis, polimyositis), no such treatment exists in many neurologic diseases, post-traumatic lesions (operations in the pharyngolaryngeal region), muscular dystrophies and the rare cases of idiopathic forms of true upper esophageal sphincter achalasia where no other cause for cricopharyngeal dysfunction can be found. Cricopharyngeal myotomy has been used in many of these conditions to relief disabling dysphagia and prevent aspiration with variable success.
In a review of the literature 12 years ago, Hurwitz found 64 p. cent good results in 237 patients collected. 24 p. cent improved only slightly after the operation and 12 p. cent experienced no improvement. Disease related mortality was 4 p. cent mostly due to aspiration in patients not relieved from dysphagia. In most of the studies cited by Hurwitz, detailed manometric studies were not done, but from his own observation he concluded, that in most patients the result of cricopharyngeal myotomy is unpredictable. More recent observations however, suggest, that preservation of voluntary deglutition, conservation of pharyngeal pressure wave and intact level of consciousness, are best predictors of a favorable outcome. In other words, patients than can be manometrically demonstrated to have isolated cricopharyngeal dysfunction, from whatever cause can almost invariably expect relief of their symptoms by the operation (table 1).
Correspondingly, good outcome can be expected in almost all patients with idiopathic cricopharyngeal failure to relax upon swallowing.
Despite a less favorable prognosis in patients with more complex deficiencies (table 2) of the swallowing mechanism, cricopharyngeal myotomy may be tried in patients that have a radiologically or manometrically demonstrable pharyngeal outlet obstruction, even when the pharyngeal pressure wave is poor, with reasonable chances of relief of symptoms, when the problem is severe enough (loss of weight, repeated aspiration) since no other form of therapy is available and the ultimate alternative often is a feeding gastrostomy and or tracheoesophageal disconnection [3, 5, 6].
Table 1. Results of cricopharyngeal myotomy dependent on preservation of pharyngeal pressure wave
|
Author |
N |
Outcome |
|
|
|
||
|
|
|
Pharyngeal pressure wave preserved |
Not preserved |
||||
|
|
|
good |
Good |
Improv. |
Poor |
||
|
Ross [7] |
23 |
14 |
1 |
|
8 |
||
|
Bonavina [2] |
12 |
8 |
1 |
2 |
|
||
|
Berg[l] |
8 |
5 |
|
|
3 |
||
|
Starlinger |
1 |
1 |
|
|
|
||
|
|
44 |
29 |
2 |
2 |
II |
||
Table 2. Results of cricopharyngeal myotomy in various diseases associated with oropharyngeal dysfunction (Modified from [4]).
|
Etiology |
N |
Outcome |
|
|||
|
|
|
good -excellent |
Improvement |
Poor |
||
|
Cerebrovascular |
33 |
17 |
9 |
6 |
||
|
Amyotrophic lat. sclerosis |
86 |
9 |
51 |
16 |
||
|
Nonvascular bulbar disease |
II |
1 |
8 |
2 |
||
|
Parkinson's disease |
6 |
4 |
1 |
1 |
||
|
Various central lesions |
8 |
2 |
4 |
2 |
||
|
Peripheral nervous lesions |
10 |
5 |
2 |
3 |
||
|
Primary muscular disease |
39 |
30 |
7 |
2 |
||
|
Idiopathic |
88 |
82 |
4 |
2 |
||
Technique
The operation itself is rather simple and consists of a left cervical incision along the anterior border of the sternocleidomastoid muscle, exposure of the esophagus by retraction of the carotid sheet laterally and the trachea and larynx anteriorly and to the right. The anterior portion of the omohyoid muscle is divided, as is the middle thyroid vein. Division of the thyroid artery may be performed but usually is not necessary if the operation is not performed for treatment of Zenker's diverticulum, which needs more extensive dissection of the dorsal aspect of the cervical esophagus. After insertion of a 32 French orogastric tube the cricopharyngeal muscle is identified and divided close to the posterior midline, taking care not to injure the underlying mucosa. The incision is then extended proximally (1-2 cm) and distally (2-3 cm) beyond the cricopharyngeal muscle, into the fibers of the distal pharyngeal constrictor and the circular esophageal muscle. The rationale for this extension is the aim to cover the whole extent of the high pressure zone as estimated manometrically that is longer (3-4 cm) than the anatomical extent of the cricopharyngeal muscle (1-1,5 cm). However the claim that this is indeed necessary has never been rigorously tested.
The divided muscle fibers are pushed laterally until bulging of the mucosa occurs. Drainage of the operation field is not necessary and patients may begin normal diet on the second postoperative day.
Operative specific complications (fistulas, bleeding, wound infection) are rarely reported (less 1 %) and mortality should be close to zero.
In conclusion, cricopharyngeal myotomy is a valuable operation for the treatment of various forms of oropharyngeal dysphagia. Best results are obtained in patients with isolated cricopharyngeal muscle dysfunction but reasonable relief of disabling symptoms can be expected in more complex deficiencies. However, voluntary initiation of swallowing and preservation of some mechanism to propell the food bolus forward from the pharynx into the esophagus is mandatory for the success of the operation. In this regard, adequate posterior movement of the tongue may be as important as preservation of pharyngeal peristalsis.
Preoperative cineradiographic and detailed manometric studies in all patients undergoing this operation are mandatory to more clearly define abnormalities of the swallowing mechanism that lead to success or failure of the operation.
References