Use of a modified Furlow Z-plasty as a secondary cleft palate repair procedure to reduce velopharyngeal insufficiency

Abstract

Cleft palate repair is done to allow for normal speech by separating the oral and nasal cavities and creating a functioning velopharyngeal valve. However, despite cleft palate repair, some patients demonstrate velopharyngeal insufficiency (VPI). An attempt was made to determine the effectiveness of a modified secondary Furlow Z-plasty in improving VPI. Fifty-five children aged between 12 and 15 years, with postoperative VPI following primary palatoplasty, were included in the study. These children underwent a modified Furlow Z-plasty. Nasometry was done to determine the change in velopharyngeal function due to the secondary Furlow Z-plasty by comparing the preoperative with the 1-year postoperative nasalance scores. A test–retest study was performed to determine the reliability of the nasometric measures. Reliability measurements of the nasometer passages revealed good reliability for 18 out of the 25 speech passages. There was a statistically significant reduction in VPI at 1 year postoperative in patients who were treated with the modified Furlow Z-plasty, with a P -value of <0.001 in all passages, except velar plosives, which had a P -value of 0.002. Patients with VPI after primary palatoplasty and treated using a modified Furlow Z-plasty had significantly lower nasalance scores at 1 year postoperative, indicating significantly improved velopharyngeal function.

Velopharyngeal insufficiency (VPI) is defined as a structural abnormality that results in incomplete closure of the velopharyngeal valve during the production of oral speech. Among other causes, VPI can be caused by inadequate length and/or movement of the soft palate. Incomplete closure of the velopharyngeal valve can cause hypernasality and/or nasal emission. VPI is considered to be the primary cause of hypernasal speech.

VPI has been reported in 5–36% of patients who have undergone primary palatoplasty for cleft palate. A variety of treatment options have been described for VPI, including secondary velar palatoplasty.

The Furlow double-opposing Z-plasty technique was initially described in 1978 for primary repair of a cleft palate. In recent years, it has been used as a secondary procedure to treat post-palatoplasty VPI. The aim of this study was to determine the effectiveness of a modified Furlow Z-plasty in improving VPI by comparing pre- and postoperative nasalance scores.

Materials and methods

Patients

This prospective cohort study was performed between February and December 2011. It was conducted with 55 consecutive non-syndromic patients with complete unilateral cleft lip and palate and postoperative VPI after primary palatoplasty. The patients ranged in age from 12 to 15 years. Of the 55 patients, 30 were male and 25 were female. This research study was approved by the local ethics committee based on the guidelines declared by the Government of India. The parents or guardians of all participants were informed verbally about the study and signed a written informed consent. All patients were operated on by a single surgeon (RRR).

Surgical procedure

A modified Furlow Z-plasty technique was used for each patient. The markings for this procedure are illustrated in Fig. 1 .

Fig. 1
Marking for the modified Furlow Z-plasty in secondary palatoplasty.

The marking for the first incision was started with a point on the midline of the soft palate corresponding to the posterior border of the hard palate (point A). The next point was marked at the middle of the base of the reconstructed uvula, or the middle of the posterior border of the soft palate in cases where the uvula had not previously been reconstructed (point B). A line was drawn to connect point A with point B. This line was then extended up to a distance of 10 mm on both the palato-pharyngeal arches (points C and D). The incision design of the oral layer was based on the original Furlow Z-plasty, with an anterior limb on the left side and a posterior limb on the right side. The marking for the anterior limb started from point A and followed a path parallel to the posterior border of the hard palate at a distance of 5 mm. It was then extended up to the retromolar area of the left side of the maxilla (point E). The posterior limb extended from point B to the right side of the soft palate at a right angle to line AB (point F). Care was taken to ensure that the lines AB, AE, and BF were equal in length. These incision markings allowed for two flaps to be raised, whereby the one on the left could be rotated posteriorly and the flap on the right side could be rotated anteriorly.

The incision was started on the oral layer from point B to A. The incision was continued from point B to points C and D. After the incisions ABC and ABD were completed, the incision AE was done. A myo-mucosal flap was raised from the nasal layer with the levator muscle bundle initially attached to the oral flap, but dissected away from the oral mucosa after raising the flap. Next, incision BF was performed. In this second flap, the oral mucosa was raised, leaving the levator muscle bundle attached to the nasal layer. The levator muscle bundle was raised from the nasal layer in a second stage. The previously closed nasal layer was left intact and not dissected as would have been done in a traditional Furlow Z-plasty ( Fig. 2 ).

Fig. 2
Extension of the nasal layer.

The closure of the nasal layer was started posteriorly by approximating the points C and D and moving anteriorly up to the intact part of the nasal layer. This closure of the nasal layer was done with 4–0 Vicryl sutures (Johnson and Johnson, India) ( Fig. 3 ). The approximation of the levator muscle bundle was done with 4–0 PDS II sutures (Johnson and Johnson, India) by repositioning the bundle transversely and posteriorly ( Fig. 4 ). Closure of the oral layer was done with a Z-plasty by transposing flap BF anteriorly and AE posteriorly with 4–0 Vicryl sutures (Johnson and Johnson, India) ( Figs 5 and 6 ).

Fig. 3
Closure of the nasal layer.

Fig. 4
Muscle approximation of levator veli palatini, palatoglossus, and palatopharyngeus muscles.

Fig. 5
Preoperative picture of the previously repaired soft palate cleft.

Fig. 6
Postoperative result of the secondary cleft palate surgery.

The result of this procedure ensured a lengthening of the soft palate by up to 10 mm and ensured that the levator muscle bundle along with the palatoglossus and palatopharyngeus muscles were positioned at the posterior-most part of the repaired soft palate.

VPI analysis

Nasometry is a method of measuring the acoustic correlates of velopharyngeal function during speech. A nasometer captures data regarding acoustic energy from both the nasal cavity (N) and the oral cavity (O) during speech and then calculates the average ratio of nasal over total (nasal plus oral) acoustic energy. This ratio is converted to a percentage value and is called the nasalance score. The nasalance score can be depicted as follows: nasalance = N/(N + O) × 100. When standardized passages are used, nasalance scores can be compared.

Using a Nasometer-II model 6450 (KayPENTAX, Lincoln Park, NJ, USA), each patient was tested both preoperatively and at 1 year postoperative by a single speech therapist (BB). The passages that were used were from a revised version of the Simplified Nasometric Assessment Procedures Test (SNAP Test-R), described by MacKay and Kummer in 2005. The SNAP Test-R uses three subtests: (1) the syllable repetition/prolonged sounds subtest, (2) the picture-cued subtest, and (3) the reading subtest.

The syllable repetition/prolonged sounds subtest includes 14 consonant–vowel (CV) syllables of pressure-sensitive consonants combined with either a low vowel (/ɑ/ as in “father”) or a high vowel (/i/ as in “heat”). It also includes two prolonged vowels and two prolonged consonants. This test provides phonetic specificity of hypernasality and/or nasal emission. The picture-cued subtest contains passages that are essentially phonetically homogeneous. For each passage, a carrier phrase is used with pictures to form complete sentences. Each passage has three pictures to elicit three sentences. Each sentence is said twice. There is a passage for each of the following: bilabial plosives, lingual–alveolar plosives, velar plosives, sibilant fricatives, and nasals. The reading subtest consists of two short, easy-to-read passages, one loaded with plosives and the other loaded with sibilants. These passages are more heterogeneous phonetically than the other two subtests, but are still more homogeneous than the ‘phonetically-balanced’ passages that are often used in clinical nasometry.

The language used to perform this test was English. Children who were unable to read English were asked to repeat the stimulus after the examiner. In such a case, the nasometer was activated only when the patient was speaking.

For each patient, the mean nasalance score was calculated for each speech sample using the nasometer software. The mean of all individual patient scores for each passage was then calculated for the preoperative evaluation and also for the 1-year postoperative evaluation. Comparisons of the pre- and postoperative nasalance scores were performed using the paired t -test.

Test–retest reliability was determined by repeating the test 1 h after it was first administered for 25 random subjects. Using the results, a paired t -test was performed.

Results

Reliability analysis

Analysis of the test–retest measurements revealed various outcomes ( Table 1 ). A reliability of lower than 0.8, a large duplicate measurement error (DME), or a P -value lower than 0.05 are indicators of relatively low measurement performance. For 18 out of 25 outcomes, the differences between the two measurements showed statistically significant reliability. The following passages showed reliability below 0.8, which is considered low: /sɑ, sɑ, sɑ…/, /ʃɑ, ʃɑ, ʃɑ…/, prolonged /i/, prolonged /m/, the picture-cued subtests of lingual–alveolar plosives and velar plosives, and the reading passages subtest of bilabial plosives with nasals.

Table 1
Test–retest reliability ( n = 25). a
Reliability Duplicate measurement error Difference P -value 95% CI
1. Syllable repetition/prolonged sounds subtest
Oral + /ɑ/ syllables
pɑ, pɑ, pɑ… 0.945 2.33 1.6 0.023 (0.2 to 3.0)
tɑ, tɑ, tɑ… 0.897 3.2 2.8 0.006 (0.9 to 4.6)
kɑ, kɑ, kɑ… 0.891 3.23 2.8 0.005 (0.9 to 4.7)
sɑ, sɑ, sɑ… 0.64 7.69 6.1 0.01 (1.6 to 10.6)
ʃɑ, ʃɑ, ʃɑ… 0.639 6.33 5 0.01 (1.3 to 8.7)
Oral + /i/ syllables
pi, pi, pi… 0.854 6.43 5.4 0.006 (1.7 to 9.2)
ti, ti, ti… 0.856 6.39 3.2 0.089 (−0.5 to 6.9)
ki, ki, ki… 0.867 5.94 4.6 0.011 (1.1 to 8.1)
si, si, si… 0.905 4.93 3 0.046 (0.1 to 5.9)
ʃi, ʃi, ʃi… 0.954 3.66 2.3 0.044 (0.1 to 4.5)
Nasal + /ɑ/ syllables
mɑ, mɑ, mɑ… 0.961 2.42 0.1 0.862 (−1.3 to 1.5)
nɑ, nɑ, nɑ… 0.961 2.53 −0.1 0.868 (−1.6 to 1.4)
Nasal + /i/ syllables
mi, mi, mi… 0.984 1.66 0.5 0.317 (−0.5 to 1.4)
ni, ni, ni… 0.969 2.1 1.1 0.082 (−0.1 to 2.3)
Prolonged sounds
Prolonged /ɑ/ 0.977 1.47 0.6 0.137 (−0.2 to 1.5)
Prolonged /i/ 0.605 9.54 1.6 0.559 (−4.0 to 7.2)
Prolonged /s/ 0.988 3.07 0.8 0.39 (−1.0 to 2.6)
Prolonged /m/ 0.663 3.69 −1.5 0.169 (−3.6 to 0.7)
2. Picture-cued subtest
Oral passages
Bilabial plosives 0.873 4.62 1.1 0.417 (−1.6 to 3.8)
Lingual–alveolar plosives 0.685 6.41 0.1 0.948 (−3.6 to 3.9)
Velar plosives 0.339 18.08 4.6 0.377 (−6.0 to 15.2)
Sibilant fricatives 0.938 3.41 −0.9 0.371 (−2.9 to 1.1)
Nasal passage
Nasals 0.849 3.67 0.6 0.543 (−1.5 to 2.8)
3. Reading passages subtest
Passages (reading)
Bilabial plosives (with nasals) 0.751 5.98 −0.6 0.744 (−4.1 to 2.9)
Sibilant fricatives (without nasals) 0.956 2.57 1.6 0.042 (0.1 to 3.1)
CI, confidence interval.

a Key to phonetic symbols: /ʃ/ = ɑsh”; /ɑ/ = vowel in “father”; /i/ = vowel in “heat”.

Comparison of pre- and postoperative nasalance values

Notwithstanding the limitations of the test–retest measurements, the differences between nasalance scores pre- and postoperatively were very clear. For all outcomes, the difference showed a statistically significant reduction in VPI postoperatively. For all but one outcome in the three subtests, a P -value of <0.001 was found. The values for the velar plosive sound also showed a reduction in VPI, with a P -value of 0.002 ( Table 2 ).

Table 2
Pre- and postoperative analysis of nasalance ( n = 55). a
Mean preoperative nasalance Mean postoperative nasalance Difference P -value 95% CI
1. Syllable repetition/prolonged sounds subtest
Oral + /ɑ/ syllables
pɑ, pɑ, pɑ… 33.64 20.55 13.09 <0.001 (9.58 to 16.60)
tɑ, tɑ, tɑ… 34.18 22.18 12 <0.001 (8.59 to 15.41)
kɑ, kɑ, kɑ… 34.45 23.25 11.2 <0.001 (7.56 to 14.84)
sɑ, sɑ, sɑ… 38.53 28.02 10.51 <0.001 (6.59 to 14.42)
ʃɑ, ʃɑ, ʃɑ… 39.58 27.78 11.8 <0.001 (8.50 to 15.10)
Oral + /i/ syllables
pi, pi, pi… 58.75 42.38 16.36 <0.001 (11.62 to 21.11)
ti, ti, ti… 60.55 44.76 15.78 <0.001 (11.36 to 20.2)
ki, ki, ki… 62.56 47.42 15.15 <0.001 (10.54 to 19.75)
si, si, si… 62.52 47.17 15.35 <0.001 (11.08 to 19.62)
ʃi, ʃi, ʃi… 61.21 44.45 16.75 <0.001 (12.43 to 21.08)
Nasal + /ɑ/ syllables
mɑ, mɑ, mɑ… 59.07 51.51 7.56 <0.001 (5.24 to 9.89)
nɑ, nɑ, nɑ… 59.67 52.11 7.56 <0.001 (5.03 to 10.10)
Nasal + /i/ syllables
mi, mi, mi… 75.04 68.24 6.8 <0.001 (4.30 to 9.30)
ni, ni, ni… 74.25 70.16 4.09 <0.001 (1.83 to 6.35)
Prolonged sounds
Prolonged /ɑ/ 31.82 19.93 11.89 <0.001 (9.79 to 13.99)
Prolonged /i/ 66.11 46.96 19.15 <0.001 (15.89 to 22.4)
Prolonged /s/ 65.76 48.71 17.05 <0.001 (11.55 to 22.55)
Prolonged /m/ 93.65 89.89 3.76 <0.001 (2.49 to 5.04)
2. Picture-cued subtest
Oral passages
Bilabial plosives 52.22 36.91 15.31 <0.001 (11.24 to 19.38)
Lingual–alveolar plosives 47.56 34.35 13.22 <0.001 (9.28 to 17.16)
Velar plosives 50.15 40.09 10.05 0.002 (3.76 to 16.35)
Sibilant fricatives 51.64 38.71 12.93 <0.001 (8.99 to 16.86)
Nasal passage
Nasals 62.24 57.53 4.71 <0.001 (2.96 to 6.46)
3. Reading passages subtest
Passages (reading)
Bilabial plosives (with nasals) 50.78 36.22 14.56 <0.001 (11.70 to 17.41)
Sibilant fricatives (without nasals) 50.69 36.43 14.26 <0.001 (10.64 to 17.88)
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Jan 16, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Use of a modified Furlow Z-plasty as a secondary cleft palate repair procedure to reduce velopharyngeal insufficiency
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