Pre-surgical Nasoalveolar Moulding (PNAM): a quantum step in discovering little smiles.
"Pre-surgical Nasoalveolar Moulding (PNAM)" was earlier known as "Pre-surgical orthopaedics" that just aimed at reducing the distance between the cleft elements to help make surgical correction easier and reduce post-surgical breakdown. (1)
Pre-surgical orthopaedics failed to address the need for correction of the deformed nasal cartilage in unilateral and bilateral clefts of lip and palate and also the deficiency of columella tissue in infants with bilateral cleft lip and palate, resulting in unacceptable psychosocial impact.
PNAM technique takes advantage of the malleability of immature nasal cartilage and its ability to maintain a permanent correction of its form. In addition the technique, also demonstrate the ability to non-surgically elongate the columella in bilateral cleft lip and cleft palate cases through the application of tissue expansion principles, which is performed by gradual elongation of the nasal stents and the application of forces that are applied to the lip and nose. (2)
PNAM represents a paradigm shift from the traditional approach and is used to mould the nasal cartilage, premaxilla and alveolar ridge into normal form and position during the neonatal period, thereby reducing the severity of the oro-nasal deformity prior to surgery. (3)
Therefore the PNAM reduces the severity of the original cleft deformity, enables surgeons to achieve better repair of lip, nose, alveolus and palate, eliminates scars associated with traditional columella reconstruction surgery and hence enhances the aesthetic outcome. (4)
Various traditionally used designs of Pre-surgical orthopaedic Appliances:
* Hoffman design (1689)--used facial binding to narrow the cleft and prevent post-surgical dehiscence.
* Hullihen design (1844)--used adhesive tape binding to narrow the cleft deformity.
* Brophy design (1927)--used silver wire, which was passed through both the cleft alveolar segments and then progressively tightened to approximate the cleft alveolar segments before the lip repair.
* Mc Neil design (1950)--used series of acrylic plates to actively moult the alveolar segments into the desired position.
* Georgiade and Lathane design (1975)--used pin-retained active appliance to simultaneously retract the pre-maxilla and expand the posterior segments over a period of several days.
* Robertson design (1983)--used passive or active acrylic appliance and external strapping, depending on the presenting clinical condition to reposition the alveolar segments and encourage self-growth.
* Brogan design (1986)--used both extra-oral strapping and intra-oral appliance.
* Hotz design (1990)--used passive orthopaedic appliance with continuous adjustment to guide growth over a prolonged period. This approach eventually delayed the lip repair until six months of age and soft palate closure until 18 months of age. This technique did not incorporate the use of extra-oral strapping on the basis that it may retard the maxillary bone growth.
Modern designs of PNAM Appliance:
* Grayson design (1993)--this design pre-surgically moulded the lip, nose and alveolus in infants born with cleft lip and cleft palate. This technique used an intra-oral moulding plate with nasal stent to mould the alveolar ridges and nasal cartilage concurrently, thereby reducing the severity of original cleft deformity, enabling surgeons to achieve efficient repair of lip, nose and alveolus. This design also eliminated the need for surgical columella reconstruction, and hence enhanced the aesthetic outcome.
* De Biase design (1995)--this design used an orthopaedic appliance that facilitated the manipulating of the alveolar segments on a continuous basis by selective trimming thereby promoting lateral shelf growth.
Objectives of PNAM in unilateral cleft lip and cleft palate cases:
* To reduce the severity of the original cleft deformity.
* To reduce the width of the alveolar cleft segments until passive contact of the original tissues is achieved:
** As the reduction of the alveolar gap width is accomplished, the alignment of the base of the nose and lip segments improves concurrently.
** Extra-oral tapes that actively bring the lip segments together are used in conjunction with the moulding plate and nasal stent.
** Taping the lips together helps to the inclined columella upright along the mid-saggital plane.
** As the lower mid-face skeletal elements (alveolar ridge and lower maxilla) improve in relation to each other, the overlying soft tissue improves concurrently.
** The alar rim, which was initially stretched over a wide alveolar cleft deformity, shows some laxity that enables it to be elevated into a symmetrical and convex form.
** The nasal tip on the cleft side is overcorrected in its forward projection, this is achieved through the use of a nasal stent, an intra-oral acrylic plate and surgical tapes.
Objectives of PNAM in bilateral cleft lip and cleft palate Cases:
* Non-surgical elongation of the columella.
* Centring of the pre-maxilla, along the mid-saggital plane.
* Retraction of the pre-maxilla in a slow and gentle process to achieve continuity with the posterior alveolar cleft segments.
* Reduction in the width of the nasal tip.
* Improved nasal tip projection.
* Increase in the nasal alar base width.
Benefits of PNAM: (5,6)
1. Proper alignment of lip, nose and alveolus is achieved, thereby enabling surgeons for better surgical repair of the cleft deformity and hence reduce post-surgical breakdown.
2. Approximation of alveolar process before surgery also enables surgeons to perform gingivoperiosteoplasty (GPP) successfully.
3. It provides stable change in nasal shape with less scar tissue and better lip and nasal form.
4. Reduces the number of surgical revisions for excessive scar tissue, oro-nasal fistulas, nasal and labial deformities, due to proper columellar elongation and lengthening.
5. With the alveolar segments in a better position and increased bony bridges across the clefts, the permanent teeth have a better chance of eruption in a good position with adequate periodontal support.
6. Maxillary growth augmentation
7. Presence of intra-oral acrylic plate that forms a barrier between the oral and nasal communication enables better feeding of the baby and eliminates nasal regurgitation.
8. Reduced psychosocial impact.
9. Better parent compliance.
Complications of PNAM: (7)
1. Locked-out segments--this occurs due to the poor and un-volunteered moulding process, wherein the greater segment moves more rapidly, without the change in position of the lesser segment, as a result, the lesser segment gets locked out behind the greater segment.
2. Nostril overexpansion (Mega-nostrils)--this occurs when the nasal stent application is started before the size of the cleft gap is adequately reduced. The premature nasal stenting exerts excessive force against the nasal tissue leading to excessive alar expansion and resulting in mega-nostrils.
3. Tissue ulceration--this occurs due to application of pressure by the intra-oral acrylic appliance, which may be due to ill-fitting appliance. At times the area under the horizontal prolabium band may also get ulcerated, if the band is too tight.
4. Skin ulceration--this occurs due to frequent application and removing of tape, resulting in irritated and ulcerated skin over the cheek region.
5. Failure to retain appliance during PNAM therapy--this usually occurs due to poor patient compliance. It may also occur due to poor parent compliance, usually when the parents are uneducated or when the appointments are frequently missed.
6. Dislodgement of the acrylic plate--it is the complication which may result in obstruction of the airway. This can only occur, if the arms of the appliance are taped too horizontally or with inadequate activation.
Prevention of the complications associated with PNAM Therapy:7
1. PNAM therapy must be closely monitored and volunteered at timely basis with adequate application of mechanics and robust principles of the therapy must be followed.
2. Tissue expanding direction and associated mechanics should be monitored vigorously and nasal stenting should commence only after the cleft gap is reduced by minimum 6 mm and more permasoft must be covered over the nasal stent tip, so as to apply gentle forces.
3. Tissue ulcerations can be prevented by coating of tissue lubricant over the appliance before insertion into the oral cavity.
4. Skin ulcerations over the cheek region can be prevented by using Duo-derm or Tega-derm, underneath the tape strapped.
5. Parents must be thoroughly educated to continue the use of PNAM appliance for their child until the therapy lasts. Feeding instructions must also be given accordingly.
6. Motivating the parents to visit the dentist on scheduled appointments and in timely manner is of utmost importance for a successful PNAM therapy.
CONCLUSION: PNAM therapy is one of the most desired techniques, prior to the surgical repair of the cleft lip and cleft palate in order to achieve the best results for managing the clefts and associated psychosocial factors. The need for enhanced aesthetic outcome is of utmost importance in the cleft patients which is certainly a quantum step in discovering the little smiles.
(1.) Watson, Debbie Sell, Pamela Grunwell. Management of cleft lip and palate, 1st ed. 2001.
(2.) Grayson BH, Shetye P.R. Presurgical nasoalveolar moulding treatment in cleft lip and palate patients. Cleft Journal 2005; 1 (1): 4-8.
(3.) Barry H Grayson, Pradip R Shetye. Presurgical nasoalveolar moulding treatment in cleft lip and palate patients. Ind J Plast Surg 2009; 42 (3): 56-61.
(4.) Shetye P. R. Presurgical Infant Orthopaedics. Journal of craniofacial Surgery 2012; 23(1): 206209.
(5.) Avid F et al. Nasal Changes after Presurgical Nasoalveolar Molding (PNAM) in the Unilateral Cleft Lip Nose. The Cleft Palate-Craniofacial Journal 49; 6: 689-700.
(6.) Suri S, Disthaporn S, Eshetu G. Atenafu, David M Fisher. Presurgical presentation of columellar features, nostril anatomy, and alveolar alignment in bilateral cleft lip and palate after Infant orthopedics with and without nasoalveolar moulding. The Cleft Palate-Craniofacial Journal 49; 3: 314-324.
(7.) Catherine T. H. Lee et al. Prepubertal mid face growth in unilateral cleft lip and palate following alveolar moulding and gingivo-periosteoplasty. The Cleft Palate-Craniofacial Journal 2004; 41(4):375-380.
Rahul Goyal , Lakshmi M. S 
[1.] Rahul Goyal
[2.] Lakshmi M. S.
PARTICULARS OF CONTRIBUTORS:
[1.] Ex Post Graduate Student, Department of Paediatric Dentistry, Jss Dental College and Hospital, Mysore, Karnataka.
[2.] Ex Post Graduate Student, Department of Paediatric Dentistry, Jss Dental College and Hospital, Mysore, Karnataka.
NAME ADDRESS EMAIL ID OF THE CORRESPONDING AUTHOR:
Dr. Rahul Goyal, #56, 3rd Cross, 3rd Stage, Gokulum, Mysore-570002, Karnataka, India.
Date of Submission: 12/09/2014.
Date of Peer Review: 13/09/2014.
Date of Acceptance: 27/09/2014.
Date of Publishing: 06/10/2014.
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|Author:||Goyal, Rahul; Lakshmi, M.S.|
|Publication:||Journal of Evolution of Medical and Dental Sciences|
|Date:||Oct 6, 2014|
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