The Lateral Port Control Pharyngeal Flap: A Thirty-Year Evolution and Followup

In 1971, Micheal Hogan introduced the Lateral Port Control Pharyngeal Flap (LPCPF) which obtained good results with elimination of VPI. However, there was a high incidence of hyponasality and OSA. We hypothesized that preoperative assessment with videofluoroscopy and nasal endoscopy would enable modification and customization of the LPCPF and result in improvement in the result in both hyponasality and obstructive apnea while still maintaining results in VPI. Thirty consecutive patients underwent customized LPCPF. All patients had preoperative diagnosis of VPI resulting from cleft palate. Patient underwent either videofluoroscopy or nasal endoscopy prior to the planning of surgery. Based on preoperative velar and pharyngeal movement, patients were assigned to wide, medium, or narrow port designs. Patients with significant lateral motion were given wide ports while patients with minimal movement were given narrow ports. There was a 96.66% success rate in the treatment of VPI with one patient with persistent VPI (3.33%). Six patients had mild hyponasality (20 %). Two patients had initial OSA (6.67%), one of which had OSA which lasted longer than six months (3.33%). The modifications of the original flap description have allowed for success in treatment of VPI along with an acceptably low rate of hyponasality and OSA.


Introduction
In 1971, Micheal Hogan introduced the lateral port control pharyngeal �ap [1][2][3]. is �ap was conceived out of frustration over the inconsistent results obtained in the correction of velopharyngeal insu�ciency with pharyngeal �aps. By noting important contributions to the understanding of physiology and dynamics of hypernasal speech by Warren, Isshiki, and Bjork [4][5][6][7], he devised a technique that could be universally applied to all patients with velopharyngeal insuf-�ciency and obtain good result with consistent elimination of hypernasal speech [1][2][3]8]. In his technique, the superiorly based �ap, lined by the nasal side of the so palate [9][10][11][12], was designed so that the lateral aperture size was controlled by the passage of a 4 mm diameter catheter. is effectively created an air passage that allowed the oropharyngeal pressure build up necessary to eliminate hypernasal speech.
Aer his initial description, the procedure evolved due to observation of the results. At the time Hogan described the LPC pharyngeal �ap, sleep apnea had not yet been described as a clinical entity [13,14]. In terms of speech intelligibility, hyponasality is preferred over hypernasality. e idea that many cle palate patients with VPI oen had good lateral wall movement allowing a �tailored width� pharyngeal �ap [15] was also not yet widely known. For this reason, Hogan initially described a single-size �ap that tended to produce very small lateral ports. Dr. Hogan intuitively began constructing larger ports in most patients and still maintained adequate results. In the past 30 years, the Hogan LPC �ap became well known for the production of hyponasality and sleep apnea. e subsequent modi�cations of Hogan�s original description, which takes these factors into account, are the subject of this paper.

Materials and Methods
irty consecutive patients undergoing pharyngeal �ap procedures for velopharyngeal insufficiency (VPI) were iden-ti�ed. Twenty-seven of these patients had VPI as a result of cle palate, and 23 of these patients had adequate followup (greater than one year) for inclusion in this study. Patients were treated at the Institute of Reconstructive Plastic Surgery and either operated on or supervised by the senior surgeon (CC). Patients were treated according to the cle VPI protocol as outlined later on. All patients were followed by the senior surgeon, pediatric otolaryngologist, and speech therapist.

Preoperative Evaluation.
Patients with velopharyngeal insufficiency underwent evaluation with video�uoroscopy or �beroptic nasal endoscopy [16,17]. e �ndings are reviewed in a multidisciplinary clinic with a plastic surgeon, a pediatric otolaryngologist, and a speech therapist. Together, a consensus was reached as to the amount of velar and pharyngeal movement.
In patients between 2.5 and 3 years of age who have not undergone intravelar veloplasty with the initial palate repair (palate closure performed at another institution), this procedure is the �rst-line treatment [18]. Many patients will attain adequate velar closure and have complete elimination of hypernasality with this procedure alone. ese patients were excluded from this study.
In patients over four years, in whom the time course is more pressed due to the difficulty in elimination of compensatory articulations acquired aer prolonged time with nasal escape, the pharyngeal �ap is the procedure of choice if the nasal endoscopy shows lateral wall movement with poor central closure [8,[15][16][17]19]. In a small minority of patients (none in our sample group), there may be good central movement with poor lateral closure. ese rare patients are treated with a sphincter procedure. In addition, patients who have had previous intravelar veloplasty are also candidates for pharyngeal �aps. Based on the �beroptic and video�uoroscopic �ndings, these patients are assigned to a small, medium-small, medium, medium-large, and large ports sizes. is corresponds with wide, medium-wide, medium, medium-narrow, and narrow pharyngeal �aps [13,15,17,20,21].

Operation.
Prior to prep and drape, the posterior pharyngeal wall and the so palate are in�ltrated with approximately 10 cc of 0.5% lidocaine with 1 : 200,000 epinephrine. e posterior pharynx should always be palpated prior to in�ltration, as patients with undiagnosed velo-cardio-facial syndrome are likely to have medialization of the carotid arteries, and care must be taken to avoid their injury. A Dingman's mouth gag is placed with the smallest tongue gag that will adequately hold the tongue on the �oor of the mouth. Placement of a larger gag will limit the ability to reach the posterior pharyngeal wall. e handle of the gag is hung on the Mayo stand edge fully open and protrudes the mandible for optimal access. e so palate is split in the midline ( Figure 1) and retraction sutures are placed. is split should stop just prior to the hard/so palate junction (see supplementary video available online at doi:10.1155/2012/237308). e posterior pharyngeal wall is visualized, and the superiorly based pharyngeal �ap of the appropriate width is outlined. As the �ap is superiorly based, its mucosal surface will be re�ected to the nasal side. It should be based as high as possible, approximately 15 mm caudal to the �ustachian tube ori�ces. e �ap is incised to the parapharyngeal space. It is not necessary to incise to the prevertebral fascia as it does not contribute to the vascularity of the �ap and results in a more painful donor site. e paired parapharyngeal spaces can be con�rmed by the presence of the midline raphe. e �ap is elevated with a peanut and the midline raphe cut with scissors. A suture is placed in the tip of the �ap for retraction.
e donor site should be closed directly except for the most proximal area. Closure decreases the postoperative pain, infection rate, and decreases downward migration of the �ap with time. It will also allow for reestablishment of the sphincteric action of the pharyngeal wall with approximation of the muscles. It is best to close the middle of the donor site �rst and use the long end of a suture for retraction to expose the most caudal aspect of the donor site. Attempting to close the most cranial or proximal area of the donor site will cause the �ap to take a tube shape and make creation of the appropriate size port difficult. Care must be taken to cauterize the edges of the cut posterior pharynx prior to closure as this is the most likely site of postoperative bleeding. is bleeding will most likely be from a cut ascending pharyngeal artery or one of its branches. Bleeding in this area may cause loss of airway and preclude oral intubation. Hemostasis is best performed with a suction cautery device. Although commercial suction cauteries are available, passing a neurotip suction through a red rubber catheter can easily create a suction cautery.
Attention should be turned to the creation of the lining �aps. It is important to consider the width of the lateral port much more than the width of the lining �ap. e lining �aps are elevated from the nasal side of the so palate and will line the oral side of the pharyngeal �ap ( Figure 2). ey are based on the posterior edge of the so palate, and the tip of the �ap is at the hard/so palate junction. e split so palate should be re�ected laterally. e rhomboidal-shaped �ap is elevated o� the underlying velar musculature. Starting at the most anterior aspect of the so palate split, an incision Plastic Surgery International 3 F 2: �levation of superiorly based pharyngeal �ap. F 3: �levation of the lining �ap from the nasal side of the so palate. �ote that the lateral extent of the lining �ap will help determine the size of the resulting lateral port.
is created toward the lateral/posterior edge of the so palate. e lateral cut edge on the nasal surface of the so palate will determine the size of the port.
e nasal lining �aps are then turned out to cover the raw surface of the pharyngeal �ap. e port is created by suturing of the lateral cut edge to a point 5 mm from the base of the pharyngeal �ap (Figures 3, 4, and 5). e lateral edge of the pharyngeal �ap is sutured to the lateral cut edge from the elevation of the lining �aps, that is, the nasal side of the so palate. e �nal suture is a horizontal mattress suture setting the tip of the �ap well beyond the most anterior so palate split in order to prevent formation of a �stula at this critical location. e suture is passed through and through (oral to nasal) the most anterior so palate. It is passed through the tip of the pharyngeal �ap in a mattress fashion and �through and through" (nasal to oral) the so palate.
e lateral edge of the tip of the lining �aps, elevated from the nasal side of the so palate, is sutured to the lateral defect of the posterior pharyngeal wall. e medial edges of both lining �aps are sutured to the midline raphe at the base of the pharyngeal �ap and to each other. e medial edges of the lining �aps are sutured together with each suture catching the midline raphe of the pharyngeal �ap. e uvula is reconstructed, and the oral side of the so palate is repaired.
A tongue stitch is placed in lieu of an oral airway as passage of an oral or nasal airway may disrupt the �ap. e air and �uid are evacuated from the stomach, and blood is suctioned from the nose and pharynx. e patient is only extubated when fully awake, and the surgeon must be present  in the room. Aer extubation, the patient is placed in a tonsillar position and kept awake. Traction on the tongue suture will both open the airway and stimulate the patient as needed.

Postoperative Management.
In the initial postoperative period, airway observation is critical. e patients are kept on continuous pulse oximetry in the initial postoperative period. e intensive care unit is usually not required. e tongue suture is usually removed the next morning. Patients are given pain control with per rectum acetaminophen and codeine and kept on IV antibiotics to decrease the risk of streptococcal infection until they are taking liquids by mouth at which time they can be converted to oral antibiotics. ey are allowed �uids immediately but are unlikely to take anything by mouth for the �rst few days. At the time they are taking adequate liquids, they can be discharged. e time course for oral intake varies dramatically. It ranges from three to nine days, but most patients take adequate �uids by mouth between three and four days. Aer several days of liquids, the patient is slowly transitioned to a so diet, which is maintained for two to three weeks.

Results
Based on the preoperative evaluation of lateral wall motion, the procedures were divided as such: 6 patients had large port design (small �aps), 3 patients had large/medium port design (small�medium �aps), 14 patients had medium port design (medium �aps), and 6 patients had small�medium port design (medium�wide �aps). e incidence of small ports (wide �aps) was zero.
ere was one patient with persistent VPI (4.3%). Five patients had mild hyponasality (21.7%). Two patients had initial sleep apnea (8.7%). One of the two had sleep apnea which lasted longer than six months (4.3%). is patient's �ap was taken down with resolution of the VPI and no hypernasality. ere was no airway compromise most likely due to hemostasis obtained prior to back wall closure.
In all patients, there was some initial nocturnal obstruction due to swelling associated with the procedure. Overall, we have seen two patterns of sleep apnea in our patients. e �rst is obstruction at �ve to six weeks when wound contracture is at its highest. e obstruction resolves over several weeks as the contracture relaxes. ere is a separate group in whom the contracture does not relax and there is resulting long-term obstruction. is may resolve over the next six to nine months, but if it does not resolve, the �ap is taken down. �ontraction of the pharyngeal �ap may also lengthen the scarred so palate [22].

Preoperative Assessment.
At the time of Hogan's original publication, there was no way to accurately assess the amount of velar or lateral pharyngeal movement preoperatively. e only measure of success was the postoperative result. As a result, in patients with some degree of pharyngeal movement, the results were typically good, and in patients with poor movement, the results were poor. ere was no way to preoperatively stratify patients into the good or poor responder groups.
Video�uoroscopy and nasal endoscopy opened a new understanding of the movement of the velum and how surgical procedures could bene�t patients [8,16,17,23]. Video�uoroscopy allowed for direct visualization of the lateral pharyngeal wall movement, identifying the location and degree of the pathology and allowing formation of a reconstructive plan. is, along with the fundamentals of lateral port control technique of described by Hogan, allow for surgeons to customize the procedure to allow for appropriately sized �aps for each patient based on the amount of movement they have prior to surgery. is results in nasal competence, good speech, and limited hyponasality.

Port Diameter.
Dr. Hogan was inspired to develop the lateral port control pharyngeal �ap by the works of Drs. Warren and Isshiki. Both showed that the critical closing diameter allowing normal speech was 20 mm 2 (Dr. Isshiki's critical diameter was 19.6 mm 2 ). Dr. Hogan observed these facts and made two ports that would have a sum total of 25 mm 2 , ("…slightly larger than our threshold value of 20 mm 2 . Because of the mesial movement of the lateral pharyngeal walls which occurs during speech") [19,24]. In his design, Dr. Hogan focused on cross-sectional area of the ports not the air�ow through the ports which is more important. According to Poiseuille's law, air�ow is directly proportional to the fourth power of the radius. us, small changes in diameter have a dramatic effect on air�ow.
erefore, two ports with a radius of 2.125 mm each (cross sectional area of 14.19 mm 2 each and a total cross sectional area of 28.38 mm 2 ) would have the same air�ow as one port with a radius of 2.5 mm (cross sectional area of 19.63 mm 2 each).
In essence, a 50% larger sum total cross sectional area of two ports would have the exact same air �ow resistance as a single port of 20 mm 2 . is of course assumes that there would be no pharyngeal movement. It can then be extrapolated that aer pharyngeal �ap, with the creation of ports, where with pharyngeal and velar movement the size of each of the two ports is reduced to an area of 14.19 mm 2 , there would be no clinically apparent hypernasality.
In today's evaluation of the patient with velopharyngeal insu�ciency, this becomes more signi�cant as presurgical evaluation of the patient can give a much clearer picture of the pharyngeal movement. e procedure is no longer forced to address the least common denominator, that is, paralytic velum and pharyngeal wall, as it can be customized for each patient depending on the speci�c needs and level of dysfunction.
Presently, the goal is to have complete velar closure. However, with two ports, even if there is not complete closure, the resulting nasal air escape would be less than that found with one port.

Sleep Apnea.
Not until recently did obstructive sleep apnea come into the attention of physicians treating velopharyngeal insufficiency [3]. Prior to this, nighttime obstruction and the resulting clinical symptoms aer pharyngeal �ap surgery were largely ignored, and the procedures touted as a success or failure solely on the effect on hypernasality. Nighttime snoring was even considered a measure of success as it indicated a low likelihood of nasal escape. However, more recent studies have shown that this important clinical entity is not only a source of signi�cant morbidities including snoring, excessive daytime sleepiness, learning disabilities, irritability, perioperative aspiration pneumonia, growth retardation, heart disease, and hypertension, but also mortality with perioperative respiratory arrest and sudden death.
e incidence of obstructive sleep apnea is controversial. Some authors report that with objective testing in a series of patients, over 90% will have some degree of sleep apnea aer pharyngeal �ap, and only some of which are clinically significant [25]. Most generally, it is quoted that an approximately 10% incidence of clinically apparent obstructive apnea and that only a fraction of these cases will require intervention [26][27][28]. In any event, the risk of postsurgical sleep apnea should be taken into account when approaching patients. With preoperative assessment and procedure individualization as we have shown, the incidence of clinically important sleep apnea can be signi�cantly decreased resulting in few patients with this complication.

Conclusions
With some modi�cations from the original description by incorporation of preoperative diagnostic testing, the lateral port control pharyngeal �ap has stood the test of time and has proven to be a powerful procedure in treatment of velopharyngeal insufficiency. Like all pharyngeal �aps, it serves to limit air�ow from the oropharynx to the nasopharynx by forming an obstruction in the dysfunctional central area. It does not add any scarring or injury to the area where there is normal anatomy and the muscle function is good, that is, laterally. It uses this lateral pharyngeal sphincteric motion, along with the motion of the levator veli palatini muscle, to create a functional, dynamic obstruction to air �ow. e lateral port control method turns the attention of the procedure to what is necessary for cure as it forces the surgeon to design a �ap where the goal is the creation of a port of appropriate size that will prevent hypernasality while still resulting in an acceptable incidence of hyponasality and obstructive sleep apnea.