The modified superiorly based pharyngeal flap

The m.odified superiorly based pharyngeal Part IV. Position of the base of the flap Hiroshi Yoshida, DDS, PhD,” John Paul Stella, .DDS,b G. E. Ghali, DDS,’ and Bruce N. Epker, DDS, PhD,d Tokyo, Japan, and Fort Worth, Texas SHOWAL UNIVERSITY,

TOKYO,

JAPAN,

AND JOHN PETER SMITH

HOSPITAL,

FORT WORTH,

The modified superiorly based pharyngeal flap surgical technique developed by Epker et al. on 13 patients with moderate to severe hypernasality. The flap base was attached close to palatal plane and was found to maintain a consistent longitudinal relationship to the level of technique corrected hypernasality in a range of patients with velopharyngeal incompetence, (ORALSURGORALMEDORALPATHOL 1992;73:13-18)

T

he surgical procedure involving a pharyngeal flap is commonly performed as a secondary procedure to correct residual velopharyngeal incompetence (VPI) subsequent to palatal closure. It is also employed as a primary procedure in combination with palatoplasty in infants or in older patients with VP1 in the absence of an overt cleft palate. Of the several established pharyngeal flap surgical procedures, the superiorly based pharyngeal flap procedure appears to be preferred by most surgeons in view of the rleported advantages over the inferiorly based flap procedure.1-3 The base of the flap in the superiorly based pharyngeal flap procedure is usually attached above the level of the arch of the atlas. However, the position of the base of the flap has been reported to migrate downward postoperatively as a result of both scar contracture between the flap and its bed on the posterior pharyngeal wall21 4-gand differential growth between aAssociate Professor, First Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa Wniversity, Tokyo, Japan; Research Fellow, Department of Oral and Maxillofacial Surgery and Center for Correction of Dentofacial Deformities, John Peter Smith Hospital, Fort Worth, Texas bVice Chairman, Department of Oral and Maxillofacial Surgery and Center for Correction of Dentofacial Deformities, John Peter Smith Hospital, FNort Worth, Texas CChief Resident, Department of Oral and Maxillofacial Surgery, John Peter Smith Hospital, Fort Worth, Texas dDirector, Department of Oral and Maxillofacial Surgery and Center for Correction of Dentofacial Deformities, John Peter Smith Hospital, Fort Worth, Texas 7/12/30254

TEXAS

was performed the level of the the atlas. This as predicted.

a scarred flap and the surrounding nasopharynx. lo, ” Patients in whom such downward migration occurs may have speech defects as a result at some time after a successful operation. Only two studies 12,t3 have been published regarding the position of the flap base after surgery. In these articles, however, Musgravet2 and Curtin et a1.t3 do not specify the position at which the flap base was attached during the surgery. Although these authors have included the term, “superior based pharyngeal flap” in their reports, the name of the surgical procedure alone does not specify an accurate description of how their procedure was performed. Thus the outcome of such surgery will vary according to the surgeon’s experience and other uncontrolled factors, unless a more detailed procedural description is provided. One of us (B. N. E.) 14,l5 has developed the modified superiorly based pharyngeal flap procedure and used it successfully on a significant number of patients with VPI.16 The purpose of this study was to objectively and millimetrically measure the position of the base of flap placed during this surgical technique and to evaluate the longitudinal positional change of the flap base by means of cephalometric analysis. MATERIAL

Thirteen patients (8 males and 5 females) who had undergone the modified superiorly based pharyngeal flap operation at the Department of Oral and Maxil13

7

le 8. Characteristics

Subjects No.

0%subjects

..~~

Type of , procedure I

.-i--~--. Age a2 j c$zgzaim surgery ~ WW (Yrle

Gender

Diagnosis*

1 2 3 4

M M F M

UCLP BCLP CVI CVI

Secondary Secondary Primary Primary

514 3110 919

5 6 I

M F M

UCLP CVI UCLP

Primary Primary Secondary

413 5/11 1213

M E 1% E

BCLP CP CVI UCLP UCLP BCLP

Secondary Secondary Primary Secondary

416 414

16/O

5110 20/11

Secondary Secondary

714 1413

715 16/10

l/4 414

9P 4110

8 Y 10 li 12 13 Mean SD

M F

5/=

Age at 2nd cephalogram ivrhol

9/7 716

1418 11/8

712

815 12/8 1219

11/3 5/s

-

610 1412 613

712

216

-

:L

Duration between swgery and 1st cephalogram iyr/mo)

Di*sation between I’st and 2nd cephalogxuns Wmoi ~~~~~~~- --~ 512 4/2 l/3

414 212, 314 116

115

112

7/4 -

011

-

l/i1 l/l0 2jll

-

314 4111

-

O/1

216

-

12/o

214

3110

214

116

217

*UCLP, unilateral cleft lip and palate; BCLP. bilateral cleft lip and palate; CVI, congenital velopharyngeal incompetence; CP, isolated cieft palate.

Table

II.

eephalometric

Measurements

analysis of position of flap Sase Mean

I

Vertical position of flap base to palatal plane SF-PP -0.7 mm* MF-PP 6.6 mm 14.2 mm PI-PP Angular position of flap base to palatal plane 184.0"
lofacial Surgery and Center for Correction of Dentofacial Deformities, John Peter Smith Hospital, Fort Worth, Texas, served as subjects for this study. Each was judged by speech pathologists to have had moderate to severe hypernasality associated with VPI, which required physical management by means of pharyngeal flap surgery. Pharyngeal flap surgery was employed as a secondary procedure to correct residual VP1 after repair of a cleft palate in eight patients, and as a primary procedure to correct VP1 in the absence of an overt cleft palate in five patients. The mean age of the subjects was 9 years 8 months, with a range

SD

Range

4.6 mm 5.2 mm 6.7 mm

-8.0 to 7.0 mm 0.5 to 15.5 mm 5.0 to 25.5 mm

17.0" 11.7" 12.5"

i56.0 to 211.0” 144.0 to 177.0" 128.0 to 168.0”

3.8 mm

11.0 to 23.5 mm

2.5 mm

16.0 to 24.0 mm

5.8 mm 5.2 mm

- 15.0 to 6.5 mm 3.0 to 18.0 mm

9.6 mm 6.8 mm

-49.0 to -16.5 mm -26.0 to -8.0 mm

the level of the anterior arch of the atlas or the body of the axis.

from 5 years 5 months to 20 years Ii months. The mean time lapse from surgery to cephalometric radiographs was 2 years 4 months, with a range from 1 month to 4 years 11 months. To longitudinally evaluate the positional change of the flap base, two cephalometric radiographs were taken of five of the 13 subjects at different periods after surgery. The period between the first and second cephalographs ranged from 1 year 3 months to 7 years 4 months, with a mean of 2 years 7 months (Table I). These five subjects also had either severe mental retardation, delayed language development, or both.

Modified

Volume 73 Number 1 PTM

Fig. 1. Cephalometric baselines and landmarks used in this study. Constructed baselines:PP, palatal plane; PTM, Pterygomaxillary plane/perpendicular plane to the palatal plane extending through the pterygomaxillary fissure; SN line, a.nterior cranial baseline. Landmarks: ANS, anterior nasal spine; PI, point of intersection of the palatal plane and the pterygomaxillary plane; SF, superior point of pharyngeal flap baseattachment at the posterior pharyngeal wall; ZF,inferior point of pharyngeal flap attachment al: the posterior pharyngeal wall; MF, midpoint of flap base attachment; AT, most anterior point of the anterior arch of the atlas; ZCV, midpoint of the inferior outline of the body of the axis.

radiograph

measurements

The radiographs were taken with the subject at rest. Cephalometric landmarks and base lines used are described and illustraled in Figs. 1 and 2. Tracings were analyzed by means of a Cartesian coordinate system established by drawing the palatal plane to represent the X axis and projecting a perpendicular linle to this plane through the pterygomaxillary fissure to represent the Y axisi l3 Linear measurements, in millimeters, were made along a line parallel to either the X or the Y axis. Considered the practical bounds of measurement accuracy in this study, the tolerance of linear measurements was taken to be 0.5 mm and that of angular measurements, 0.5 degree. In the longitudinal study, thle vertical distance between each point and the anterio’r cranial baseline (SN) line were measured to evaluate the positional change with growth. Speech

based pharyngeal flap

15

I

PP

METHODS Lateral cephalometric

superiorly

evaluation

Since nasality has been found to be significantly related to velopharyngeal valving,17 intelligibility of speech, and nasal emission,*8 nasality rating seemed

Fig. 2. Measurements made from cephalometric radiographs taken with subjects at rest. Vertical position to SN line: SF-SN, vertical distance from SF to SN line; ZF-SN, vertical distance from IF to SN line; PZ-SN, vertical distance from PI to SN line; AT-SN, vertical distance from AT to SN line; ZCV-SN, vertical distance from 2CV to SN line. Position of flap baseto the palatal plane: SF-PP, vertical distance from SF to the palatal plane; MF-PP, vertical distance from MF to the palatal plane; IF-PP, vertical distance from IF to the palatal plane;
to be the best single measure by which to appraise velopharyngeal competence after pharyngeal flap surgery. l2 Nasality ratings were used to evaluate speech after surgery in 12 of the subjects. In one patient, cephalographs were available only 1 month after surgery. Two speech pathologists experienced with cleft palate rated the degree of nasality on a four-point scale: normal voice quality and mild, moderate, or severe hypernasality. RESULTS Position of flap base

Vertically, between the position of the flap base and the palatal plane, the superior point of flap base attachment at the posterior pharyngeal wall was located 0.7 mm above the level of the palatal plane. The midpoint of the flap base was located 6.6 mm below the level of the palatal plane. The angular relationship between the position of the,superior point of the flap base relative to the palatal plane was 184 degrees, and the angular position of the midpoint of the flap base relative to the palatal plane was 162.7 degrees. The length of the flap base attachment along the pharyngeal wall was 16.7 mm. The horizontal

Teble Hi. Posioperative nasality chso?ca~-

-

~abk iit. LongitudmA changes in the positions of Clap base attachment according to cephalometric analysis

-:iz

Normal voice quality Mild hypernasality Moderate hypernasality Severe hypernasality

10 1 0 1

distance from the midpoint of the flap base to the pterygomaxillary plane was 20 mm. Also vertically, between the flap base and the atlas and axis, the superior point of flap base attachment was located 5.5 mm above the level of the anterior arch of the atlas and 3 1.4 mm above to the level of the base of the axis. The inferior point of the flap base was 9.7 mm below he level of the atlas and 16 mm above the level of the axis (Table II). asality

Ten of the 12 subjects were judged to have normal voice quality, one to have mild hypernasality, and one to have severe hypernasality (Table III). The two subjects with mild and severe hypernasality after surgery also had severe mental retardation and delayed language development. The cephalometric analysis failed to reveal any significant difference between these two patients and the other 10 patients. Longitudinal

change

in position

of fla

The differences between the measurements obtained from the first and second cephalometric radiographs were evaluated to ascertain positional changes of the base of the flap in the five subjects with two longitudinal postoperative radiographs. The vertical positions of the superior and inferior points of the flap base relative to the level of the palatal plane were found to have migrated downward 2.1 mm and 3.4 mm, respectively, because the downward migration of these two points to the SN line was greater than that of the point of intersection of the palatal plane and the pterygomaxillary plane to the SN plane. The angular position of the superior and inferior points of the flap base relative to the level of the palatal plane decreased 4.6 and 1.7 degrees, respectively. The width of the flap base attachment increased 0.8 mm, and the horizontal length of the flap increased 1.2 mm in the period between radiographs. The vertical position of the flap base changed with time relative to the level of the atlas; the superior point and the inferior point were located 0.6 mm and 1.9 mm below the level of the atlas, respectively. These distances are relatively small since these two points and the atlas had migrated downward relative to the

Measurements

Mean

Vertical position to SN line 3.8 mm SF-SN 5.0 mm IF-SN 2.9 mm PI-SN 3.9 mm AT-SN 6.3 mm XV-SN Vertical position of flap hase to palatal plane 2.1 mm SF-PP 3.4 mm IF-PP Angular position of flap base to palatal plane -4.6’*
Range

SD

3.4 3.9 2.8 3.6 4.9

mm mm mm mm mm

1.5 mm 1.9 mm

4.2’ 3.5”

0 0.5 0 0 0

to to to to to

7.5 mm 10.5 mm 6.5 mm 7.5 mm 10.5 mm

0 to 4.0 mm 0.5 to 5.5 mm

-10.0 to 0” -5.5 to 2.0”

0.8 mm

0 to 2.0 mm

1.1 mm

0 to 2.0 mm

0.7 mm 0.7 mm

-0.5 to 1.5 mm? 1.0 to 3.0 mm

2.6 mm 2.5 mm

-5.5 to 0 mm -6.0 to 0 mm

*Minus value (-) in angular position indicates the decreaseat angle with progressive age in duration between tirst and second eephalograpbs taken. +Minus value (-) in length indicates the positions of SF or IF displaced upward relative to the level of the atlas or axis with progressive age in dtrrarion between first and second cephalographs taken.

SN lines by a similar amount. However, both the superior and inferior points migrated downward less than the axis, relative to the SN line, resulting in an increase in the vertical distance between the axis and the points on the flap base; that is: the flap base migrated upward relative to the level of the axis (Table IV). These five patients did not show significant changes in the degree of nasality during the follow-up period.

A superiorly based pharyngeal flap with the base of the flap at a low level on the posterior pharyngeal wall pulls the soft palate in an inferior and/or posterior direction and may actually restrict normal elevation of the velum. It is reported that a significant number of patients with residual VP1 after a pharyngeal flap operation have this type of restrictive flap.2>5-7,l9 To achieve a more physiologic closure between the palate and the pharynx at the level of normal velopharyngeal contact, and to prevent the velum from being

ModiJied superiorly

Volume 73 Number 1

based pharyngeal jap

I?

Table V. Comparisons between the results of present study and the studies by Musgrave and Curtin et al. based on cephalometric measurements

~ Measurements

Vertical position of flap base attachment to palatal plane MF-PP mean 6.6 mm 14.5 mm* 5.6 mm SD 5.2 mm Angular position of flap base attachment to palatal plane 162.7” 150.8”*
18.4 mm* 6.8 mm 144.6”* 10.8” 19.6 mm 4.4 mm

13.9 mm* 5.6 mm 150.7”* 8.5” 23.8 mm* 3.6 mm

16.5 mm* 7.5 mm 147.0°* 11.1” 17.0 mm 4.2 mm

24.9 mm* 3.9 mm

*Significant at 0.01 level to present study (t test). tSignificant at 0.05 level to present study.

tethered to the pharyngeal wall in an inferior direction, the base of the flap should be positioned well above the level of the tubercle of the atlas during surgery. Accordingly, it is important to measure the position of the flap base after surgery because of its close relationship to speech intelligibility. However, there are only two reports 12,l3 in the literature that objectively and quantitatively evaluate the relationship of the position of the flap base to the level of the palatal plane after a pharyngeal flap operation. In one of these, Musgravet2 divided 60 patients--56 with a superiorly based flap and 4 with an inferior based pharyngeal flap-into nonnasal and nasal groups according to postoperative nasality ratings and analyzed cephalometric radiographs taken approximately 8 months after surgery. He found that the position of the flap base attachment with subjects at rest was at a significantly higher level along the pharyngeal wall in the nonnasal group than in the nasal group. In the other report, Curtin et al.13 measured the position of the flap base in cephalographs of 20 subjects taken 8 months after a pharyngeal flap procedure, to compare the results of the operation employed as a primary and as a secondary procedure. In their study, all 20 subjects had undergone wide superiorly based pharyngeal flap surgery. They reported that in the primary procedure group the pharyngeal base attachment was broader and more extensive, the angular positions of the flap were higher, and pharyngeal base attachments were closer to the palatal plane. Statistical comparisons between the results of the present study and the studies by Musgrave and by

Curtin et al., based on cephalometric measurement, revealed that the attachment of the flap base in the present study was significantly closer to the palatal plane. The width of the flap base attachment was narrower in these subjects than in the subjects of the other studies. In our subjects, there appeared to be less scar formation at the base of the pharyngeal flap as evidenced by a relative lack of the thick scar band that tends to form as a result of scar contracture.2 The horizontal length of the flap in our subjects was found to be shorter, which resulted in less nasopharyngeal depth. This plus the higher flap base attachment along the posterior pharyngeal wall seemed to serve as a suitable obturation and to contribute to velopharyngeal closure at the physiologic site12 (Table V). The pharyngeal flap has been reported to migrate downward postoperatively for two reasons: (1) the scarring of the donor site2>4-9 causing inferior and post,erior traction at the base of the flap2 and (2) the differential growth between the scarred flap and the surrounding nasopharynx.“> l1 Because of the scar contracture between the flap base and its donor site, the flap base attachment may thicken. On the other hand, in the downward migration because of differential growth between a scarred flap and the surrounding nasopharynx, the flap base may migrate more than the cervical vertebrae. As a result of the inferior displacement of the pharyngeal flap, the velum is tethered to the pharyngeal wall at a level below the normal site of velopharyngeal contact, and a speech defect may recur because of restriction of the palatal elevation” In this study, the length of the flap base attachment along the posterior pharyngeal wall was longitudinally consistent. In addition, while the

!.)A.&L

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3RAL.

PKTtiOL

January 1992

flap base a.ltachment migrated slightly downward relative to the level of the palatal plane, it maintained a consistent relationship to the level of the atlas and was actually displaced slightly upward relative to the level of the axis. Accordingly, in this small group, we considered that scar contracture and differential growth in the nasopharyngeal region have little effect on the position of the flap base attachment along the posterior pharyngeal wall. The relationship between pharyngeal hap procedures and postoperative reduction in hypernasality has been studied by many investigators, reporting speech success rates above 80%. Ten of 12 of our subjects demonstrated an absence of hypernasality, one showed improvement with mild residual hypernasality, and one showed no improvement. A number of factors related to poor speech results after pharyngeal Aap surgery have been described. In the case with no speech improvement, the poor result was attributed to severe mental retardation with concomitant delayed language development. However, four other subjects with mental retardation, delayed language development, or both did show satisfactory improvement. Although it is reported that the hypernasality in such cases has not been improved by pharyngeal flap surgery, 8, lo, 2o our results with this small group demonstrate that this modified procedure offers a significantly higher incidence of nasality reduction in such cases and encourages us to use this procedure with future patients. ONCLUSlO In the modified superiorly based pharyngeal flap surgical procedure developed by Epker et al., the attachment of the flap base is made at a significantly higher position along the pharyngeal wall and maintains a consistent longitudinal relationship to the level of the atlas. As predicted, this technique corrected hypernasality in patients with VPI. EFERENCE 1. Randall P, Whitaker LA, Noone RB, Jones WD. The case for inferiorly based posterior pharyngeal flap. Cleft Palate J 1978;15:262-5. 2. Skoog T. The pharyngeal flap operation in cleft palate. Br J Plast Surg 1965;18:265-82.

3. Yules RB, Chase RA, BlocXsma R, Lang BR. Secondary techniques for correction of palatopharyngeal incompetence. In: Grabb WC, Rosenstein SW, Bzoch KR, ads. Cleft lip and palate. Boston: Little Brown, 1971:451-89. 4. Hirshowitz B, Bar-David D. Correction of poor speech due to a low pharyngeal flap attachment by a V-Y advancement procedure. Cleft Palate J 1977;14:167-75. 5. Qwsley JQ, Lawson LI, Miller ER; Harvald EP, Chierici G, Blackfield HM. Speech result from the high attached pharyngeal flap operation. Cleft Palate J 1970;7:306-17. 6. Weber J, Chase RA, Jobe RP. The restrictive pharyngeal flap. Br J Plast Surg 1970;23:347-5 1. 7. Blackfield HM, Owsley JQ, Miller ER, Lawson LI. Cinefluorographic analysis of the surgical treatment of cleft palate speech; a preliminary report. Plast Reconstr Surg 1963;3 1:54253. 8. Gwsley JQ, Lawson LI, Chierici GJ. The re-do pharyngeal hap. Plast Reconstr Surg 1976;57:180-5. 9. Millard DR ed. Cleft craft: the evolution of its surgery. III. Alveolar and palatal deformities. Boston: Little Brown, 1980;636-8. 10. Cosman B, Falk AS. Pharyngeal flap augmentation. Plast Reconstr Surg 1975;55:149-55. 11. Figueora AA, Aduss H, Subtelny JD, et al. Vertical growth changes in the position of the base of the pharyngeal flap. Presented at 47th annual meeting, Am Cleft Palate-Craniofacial Association; 1990. !.2. Musgrave KS. A cephalometric radiographic evaluation of pharyngeal flap surgery for correction of palatopharyngeal incompetence. Cleft Palate J 1971;8:118-44. 13. Curtin JW, Subtelny JD, Oya N, Subtelny JD. Pharyngeal flap as a primary and secondary procedure. Cleft Palate J !973;10:1-13. :4. Epker BN, Wu J. The modified superior based pharyngeal flap. Part I. Surgical technique. ORAL SURG ORAL MED ORAL PATHOL 1990;70:247-50. 15. Wu J, Epker BN. The modified superior based pharyngeal flap. Part II. AA anatomical study. ORAL SURG ORAL MED ORAL PATHOL 1990;70:251-5. 26. Theranon W, Stella JP, Epker BN. The modified superior based pharyngeal flap. Part III. A retrospective study. ORAL SURGORAL MEDORALPATHOL 1990;70:256-67. 17. Subtelny JD, Koepp-Baker H, Subtelny JD. Palatal function and cleft palate speech. J Speech Hear Disord 1961;26:213-24. 18. Subtelny JD, McCormack RM, Curtin JW, Subtelny JD, Musgrave KS. Speech, intraoral air pressure, nasal airflowbefore and after pharyngeal flap surgery. Cleft Palate J E970;7:68-90. 19. Owsley JQ, Creech BJ, Dedo HH. Poor speech following the pharyngeal flap operation: etiology and treatment. Cleft Palate J 1972;9:312-8. 20. Schulz R, Heller JC, Gens GW, Lewin M. Pharyngeal flap surgery and voice quality-factors related to success and failure. Cleft Palate J 1973;10:166-75. Reprint requests: Hiroshi Yoshida, DDS, PhD First Department of Orai and Maxillofacial Surgery School of Dentistry, Showa University 2-l-l Kitasenzoku, Ohta-ku, Tokyo 145 Japan