Cricopharyngeal Muscle Hypertrophy

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                                                                       Cricopharyngeal                                                     Muscle
                                                                       Hypertrophy:                                          Radiologic-Anatomic
                                                                       Correlation




                                      William     E. Torre&               There is a divergence      of opinion concerning       the cncopharyngeal         muscle   defect
                           James       L. Clements,        Jr.1        commonly    seen in the pharyngoesophageal        area on barium esophagram.          Some observ-
                                        Garth     E. Austin2           ers believe this defect is the result of neuromuscular      dysfunction     with the demonstration
                                                                       of the unrelaxed     muscle   bundle;   however,    others believe      it is the result of actual
                                          Kathryn    Knight2
                                                                       hypertrophy    of the cncopharyngeal      muscle.    Radiologic    and pathologic       study of 24
                                                                       unselected     autopsy     cases     revealed   cricopharyngeal       hypertrophy       in 13 cases     by radio-
                                                                       logic criteria. Histologic examination   revealed           that the cncopharyngeal    muscle thickness
                                                                       was uniformly     greater  in these cases than             in the radiographically   normal cases. The
                                                                       cricopharyngeal      muscle defect is associated             with actual hypertrophy   of the cncophar-
                                                                       yngeal muscle in many cases.



                                                                          A posterior    indentation      of the esophageal          lumen is often observed             radiologically
                                                                       at the level of the lower cervical spine. This impression                        has had several names,
                                                                       including esophageal         lip, spasm, hypopharyngeal                 bar, or hypertrophy        of the crico-
                                                                       pharyngeal     muscle (fig. i). In our previous               clinical study [i ], the cricopharyngeal
                                                                       muscle defect was demonstrated                   in 1 8% of i 00 unselected              patients     on barium
                                                                       esophagram.
                                                                           Opinions differ as to the clinicopathologic             significance      of this posterior      indentation
                                                                       on the esophageal         lumen. Most authors             agree that this esophageal               narrowing      is
                                                                       caused by contraction          of the transverse       fibers of the cricopharyngeal               muscle. Two
                                                                       main bodies ofthought           have emerged:       One group postulates             that the incoordination
                                                                       of the pharyngoesophageal             structures     during deglutition         may explain this posterior
                                                                       esophageal      defect; the second group attributes                  the cricopharyngeal         indentation     to
                                                                       muscle hypertrophy.         To resolve this question,            we examined        24 unselected        autopsy
                                                                       specimens      for radiographic         and pathologic          evidence      of cricopharyngeal           muscle
                                                                       hypertrophy.


                                                                       Materials     and Methods
                                                                         En-bloc resection       of the cervical esophagus,         trachea, and larynx       was done during        post-
                                                                       mortem examination         of 24 unselected   patients.       The proximal  ends       of the specimens       were
                                                                       closed above the junction          of the hypopharynx       and the esophagus;         barium was introduced
                                                                       into the lumen    of the esophagus     from below by a catheter     passed through     its occluded
                                                                       inferior margin. The specimens    were then radiographed   with the esophageal    segment partially
      Received         April 29, 1983; accepted       after revision
December 29, 1983.                                                     and then fully distended    with contrast   medium (fig. 2). The radiographs    from the autopsy
      1   Department        of   Radiology,   Emory       University
                                                                       specimens     were assigned        a grade from 0 to 4, determined        by the size of the cricopharyngeal
Hospital, 1364 Clifton Rd., N.E., Atlanta, GA 30322.                   muscle in the maximally     distended    specimen.    The defects detected     in the specimen    radi-
Address   reprint          requests to W. E. Torres.                   ographed   correlated  well in both configuration      and location with those seen in the living
   2 Department              of Pathology,  Emory    University        subject. Measurements     of the transverse    diameter of vertical pharyngeal     wall were taken at
Hospital,       Atlanta,    GA 30322.                                  the point of greatest indentation    on the posterior   pharynx (fig. 3).
AJR  141:927-930,   May 1984                                              After this procedure,      the specimens       were fixed in neutral buffered        formalin    for gross and
0361 -803x/84/1   425-0927                                             microscopic  study. Pathologic          examination     was performed      without     knowledge      of the radi-
C American Roentgen Ray Society                                        ographic grade of the individual        specimens.     After gross inspection      of the tissue,   three vertical
928                                                                                  TORRES     ET AL.                                                                   AJR:142,        May 1984




sections, each 5-6 cm long, were taken through the posterior pha-                               almost   complete       correlation        between           the   radiologic        and      path-
ryngeal wall to include the cricopharyngeal muscle. This muscle was                             ologic grades       of the cricopharyngeal           muscle      hypertrophy.
recognized as a collection of oblique and transverse muscle fibers                              Furthermore,      the measured        thicknesses       of the cricopharyn-
located immediately   cephalad to the predominantly   longitudinal  fibers                      geal muscle for individual         specimens      correlated     well with the
of the thinner walled upper esophagus.     The degree of hypertrophy
                                                                                                radiographic     grade. (Examples         of the histology      of specimens
of the cncopharyngeal    muscle in each specimen    was graded from 0
                                                                                                showing      no hypertrophy,       1 + hypertrophy,        and 4+ hypertro-
to 4+, primarily  on the basis of muscle thickness.   However,     muscle
cell size and density of packing of muscle fibers were also taken into
                                                                                                phy are shown         in fig. 4.) The muscle          thickness      of the 11
consideration.                                                                                  cases with radiologic        grade 0 was 1 .5 ± 0.5 mm (mean ± 1
                                                                                                SD); that of the nine cases graded 1 + or 2+ was 2.9 ± 0.2
Results                                                                                         mm. In cases of radiologic            grade greater        than 2+, muscle
                                                                                                thickness     was 4.2 ± i .8 mm. The large standard                   deviation
   Table 1 summarizes the radiologic                        and pathologic    changes
                                                                                                for the muscle thickness         of specimens      showing 2+ or greater
found in the study of the anatomic                          specimens.     There was
                                                                                                hypertrophy      was due to one very hypertrophied                   specimen
                                                                                                with a muscle thickness          almost twice that of any other spec-
                                                                                                imen examined.
                                                                                                   The   mean       muscle     thickness            of the    radiologically           negative
                                                                                                cases was compared             with means of those cases showing           1+
                                                                                                hypertrophy        or greater      using Student’s       f-test. The muscle
                                                                                                thickness       of radiologically      negative    cases was significantly
                                                                                                different    from the thickness         of 1 + positive cases (p < 0.Oi)
                                                                                                and from the 2+ to 3+ positive                cases (p < 0.01). Although
                                                                                                the mean muscle thickness              of the 1 + positive cases was less
                                                                                                than that for the 2+ to 3+ positive cases, this difference               was
                                                                                                not statistically     significant    (p > 0.10).


                                                                                                Discussion

                                                                                                   There is a great divergence            of opinion as to the pathologic
                                                                                                and clinical significance        of the cricopharyngeal      indentation       [1-
                                                                                                   1.
                                                                                                i 1 In our autopsy           study, and in a previous          clinical study,
                                                                                                large cricopharyngeal         muscles were identified radiographically
                                                                                                in patients with no symptoms              of dysphagia.     However,       Crich-
                                                                                                low [2] has stated, “There is no normal radiologic                    picture of
                                                                                                the cricopharyngeus           because      the cricopharyngeus          is never
                                                                                                visualized   if the esophagus          is acting normally.”
    Fig.   1 -A,    Radiograph       of normal   cervical   esophagus.   B,   Radiograph   of
                                                                                                   According      to Killian    [3], the cricopharyngeal          muscle con-
patient.   Cricopharyngeal       impression.                                                    sists of two major parts: a pars obliqua and pars fundaforma


                                                                                                                                                Fig. 2.-Radiograph              of  normal     ana-
                                                                                                                                            tomic   specimen      distended        by liquid    bar-
                                                                                                                                            ium. No cricopharyngeal              muscle    impres-
                                                                                                                                            sion.




                                                                                                                                                Fig. 3.-Radiographs             of autopsy      spec-
                                                                                                                                            imens from two patients.            Cricopharyngeal
                                                                                                                                            impression.
AJR:142,       May    1984                                             CRICOPHARYNGEAL                     MUSCLE       HYPERTROPHY                                                                        929


or transverse                part   (fig. 5). The oblique                fibers    arise     from    the      goconstrictors       and have identical      function.       The transverse
posterior         part       of the       lower     third    of the      lateral   surface      of the        fibers arise from the lateral margin of the cricoid cartilage,
cricoid cartilage,    extending   up and back to insert                                      into the         passing backward        horizontally   without     interlinking    dorsally   in
median    raphe to the other pharyngeal       constrictors.                                     These         a raphe, forming a sphincter.        This horizontal        band of fibers is
fibers are intimately     fused with those of the inferior                                    pharyn-         responsible,      along with the uppermost          bundle of the esoph-
                                                                                                              ageal circular muscle, for closure of the mouth of the esoph-
                                                                                                              agus [4, 5].
TABLE          1 : Correlation         of Radiologic    and Pathologic                Changes        in
                                                                                                                  Many observers      have concluded      that most cricopharyngeal
Anatomic         Specimens            of Cricopharyngeal     Muscle
                                                                                                              diseases     cause cervical dysphagia        as the main clinical mani-
     Radiologic Grade:                n            cncopharyngeMusde                                          festation.     However,   this has not proved to be true. In 1966,
                                                                                     Thkness(mm),
     Patholoc   Grade                                        ness(   )                 Mean±SD                Seaman [5] postulated          that pharyngoesophageal            motility in-
0:                                                                                                            coordination      may be enough      to explain this posterior         esoph-
     0                              10            2.0, 1.8, 1.7, 1.5*,                                        ageal defect. He believed that it is not necessary               to attribute
                                                      1 3*,    ,
                                                               *, 0.6                  1 .5 ± 0.5             cricopharyngeal          muscle      indentation         to spasm      or hypertrophy.
   1+                                 1           2.3                                                         If the cricopharyngeal            muscle fails to open at the correct time
1+:
                                                                                                              or if it contracts            prematurely,    a defect    would   readily  be
   1+                                 6           3.Ot,     2.8, 2.6
                                                                                                              apparent      in the barium column. This entity has been referred
2+:
  2+
     1+
                                      2
                                      1
                                                  3.9, 3.5
                                                  2.3
                                                                        J             2.9    ± 0.2            to as cricopharyngeal             achalasia,  defined as the failure of the
                                                                                                              muscle to relax quickly enough                during deglutition   to permit
>2+:
     4+                               1           7.9          ‘1                                             the bolus to pass freely through                the hypopharynx      into the
     3+                               1           4.5          1                      4.2±1.8                 esophagus.
     2+                               2           4.0, 3.4     J                                                  In cricopharyngeal           muscle dysfunction,    the patient seldom
     .   Two cases.                                                                                           complains       of difficulty     swallowing.  The absence of symptoms
     t Four cases.                                                                                            is an unreliable        sign    in the evaluation         of normalcy        of swallow-




                                                                                                                 Fig. 4.-Histologic     sections   of representative     specimens    of cricopharyngeal
                                                                                                              muscle.     H and E x45. Bar scale = 0.5 mm. A, No hypertrophy.                          B, 1 +
                                                                                                              hypertrophy.   C, 4+ hypertrophy (only part of muscle is shown).
930                                                                                   TORRES     ET       AL.                                                        AJR:142,    May 1984



                                                                                                                                               Fig.     5.-Frontal   (A)   and   lateral    (B)
                                                                                                                                            views     of anatomy.




        Inf.

                                                                                                                          lique


                                                                                                                         Lnsverse
pharyngeus




                                                                                                                                    jus

       if Id,ii’z’eL

A                                                                      B

 ing [5]. Over a long period, patients with abnormal                          deglutition        cerebral vascular        accidents,      neuritis, thyrotoxicosis,        trauma,
may become conditioned                to swallowing          slowly and carefully;               or muscle       dysfunction.        Our autopsy         study    indicates      that
they may have unconsciously                  altered their diet, taking in only                  anomalies      of the cricopharyngeal             muscle occur more often
small amounts         of food at a time. The cricopharyngeal                        inden-       than is detected          in the living patient,          even when special
tation can appear with other forms of esophageal                            dysfunction          attention   is directed to this area.
in patients     with symptoms            of dysphagia.          A variety of abnor-                  In a previous     clinical study [1 ], we demonstrated                 the cr1-
malities of the swallowing             mechanisms           may be present,            such      copharyngeal        muscle defect in i 8% of 1 00 unselected                     pa-
as pharyngeal        constrictor      paresis, dysfunction              of the epiglot-          tients on barium swallow examination                 [1 ]. Our autopsy        study
tis, and aspiration         of material        into the larynx and laryngeal                     provides     strong evidence          that the cricopharyngeal              muscle
vestibules     [5]. When cricopharyngeal                   dysfunction        is present         dysfunction      in most cases is associated             with actual hypertro-
in individuals      without      dysphagia,         it is most often a solitary                  phy of the cricopharyngeal             muscle and is not simply due to
phenomenon.                                                                                      muscle spasm or pharyngoesophageal                     incoordination.
     Many authors        have observed             variation      in the size of the
indentation       on barium         studies        and between              subsequent
                                                                                                 REFERENCES
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only identified for a brief moment during the swallowing                           phase.         1 Clements
                                                                                                      .               JL, Cox GW, Torres WE, Weens HS. Cervical esoph-
Ekberg and Nylander            [4] theorize that the ability to reproduce                                 ageal webs:       a roentgen     anatomic      correlation.     AJR 1974;
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bolus. Symptomatic            patients may make repeated                     small swal-          2.      Crichlow TVL. The cricopharyngeus           in radiography       and cinera-
                                                                                                          diography.    Br J Radiol 1956;29:546-556
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                                                                                                  3.      Killian G. Mouth of esophagus. Laryngoscope              1907;1 7:421-428
difficult.
                                                                                                  4.      Ekberg 0, Nylander G. Dysfunction         of the cricopharyngeal         mus-
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                                                                                                          cle. Radiology    1982;143:481-486
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mum distension           was obtained,            which may explain                the in-        6.      Helsper JT, Lance JS, Baldridge        ET, Vap JG. Cricopharyngeal
creased frequency           of detection        of this defect in our autopsy                             achalasia. Am J Surg 1974;128:521-526
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[1]. The degree of dysphagia                does not always correlate                   with              1981;1 94:279-287
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cricopharyngeal         achalasia      or dysphagia           into two categories:
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the primary cricopharyngeal               achalasia,       which is the idiopathic
                                                                                                       appearance      of the “esophageal     lip.” AJR 1959;81 :570-575
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                                                                                                 10. Palmer ED. Disorders          of the cricopharyngeus     muscle: a review.
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tumors,     those who have had laryngectomy,                          and those with             i i . Cruse JP, Edwards        DAW, Smith JF, Wyllie JH. The pathology        of
incoordination         of   the    swallowing         mechanism          due     to    polio,          cricopharyngeal      dysphagia.   Histopathology   1979;3:223-232