Transpalatal distraction osteogenesis prior to alveolar bone grafting in cleft lip and palate patients

Abstract

Alveolar bone grafting is a standard method for treating alveolar cleft. To ensure the best outcome, improving the arch form as well as soft tissue quality in the area around the cleft is recommended. In this study, 11 patients who presented with alveolar cleft and collapsed maxillary arch were treated in the following sequence: transpalatal distraction osteogenesis followed by soft tissue surgery in some cases and by cancellous bone graft. In all cases, transpalatal distraction osteogenesis successfully corrected the transverse maxillary deficiency. One case showed a complete loss of the bone graft. Other minor complications were reported but they did not affect the final outcome.

Bone grafting of the alveolar cleft is an integral part of rehabilitation of patients with cleft lip and palate deformities. The benefits and goals of this procedure include stabilization of the maxillary arch, elimination of oronasal fistulae, creation of bony support for subsequent tooth eruption and dental implant placement, and reconstruction of the hypoplastic pyriform aperture .

Collapse of the maxillary minor segment is one of the most common features in patients with repaired unilateral cleft lip/palate . To achieve a high success rate in grafting these defects, optimizing maxillary arch alignment before graft placement is recommended. This usually involves transverse maxillary expansion . Several techniques have been recommended for improving the arch form before grafting. These include orthodontic maxillary expansion, two stage Le Fort I osteotomy, rapid maxillary expansion, and surgically assisted rapid maxillary expansion. Generally, non-surgical expansion is indicated in patients under the age of 12 years and is associated with complications when used in skeletally mature patients . Recurrence of the collapse and alveolar bone effects are among the reported complications .

Transverse maxillary expansion with a bone-borne transpalatal distractor has been used with favourable results in congenital and acquired transverse maxillary deficiency . Most of the published data on transpalatal distraction osteogenesis relate to series applied in non-congenital defects or case reports applied in congenital cases . The authors’ aim was to evaluate the outcome of palatal expansion by bone-borne transpalatal distraction in collapsed maxillary arch and its influence on the success of subsequent alveolar cleft grafting in cleft lip and palate patients.

Patients and methods

From 2002 to 2007, 11 patients with different forms of alveolar cleft were included in this study (3 females and 8 males). The age of the patients at the time of presentation ranged from 15 to 28 years (mean 19.7 years). The patients were treated with transpalatal distraction osteogenesis, then optional soft tissue improvement, followed by alveolar bone grafting.

The inclusion criteria were: unrepaired unilateral or bilateral alveolar cleft; no previous attempt at alveolar bone grafting; no previous active orthodontic treatment; unilateral or bilateral collapsed maxillary arch with skeletal cross bite that could not be corrected by non-surgical expansion as indicated by the treating orthodontist; erupted canine at the time of presentation.

Treatment protocol

Maxillary expansion was carried out using a bone-borne transpalatal distractor (Surgi-Tec, Bruges, Belgium). After 5–7 latency days, expansion was achieved at a rate of 0.33–0.66 mm per day until the required transverse maxillary width was reached. The device was retained for 4 months for consolidation and removed under local anaesthesia. After the first 2 months of the consolidation period, the soft tissue on the buccal side of the maxilla was evaluated. In case of inadequate soft tissue mucosa to cover the subsequent bone graft, vestibuloplasty was performed. 2 months after removal of the distractor, grafting of the alveolar cleft was carried out with an iliac cancellous bone graft.

Treatment protocol

Maxillary expansion was carried out using a bone-borne transpalatal distractor (Surgi-Tec, Bruges, Belgium). After 5–7 latency days, expansion was achieved at a rate of 0.33–0.66 mm per day until the required transverse maxillary width was reached. The device was retained for 4 months for consolidation and removed under local anaesthesia. After the first 2 months of the consolidation period, the soft tissue on the buccal side of the maxilla was evaluated. In case of inadequate soft tissue mucosa to cover the subsequent bone graft, vestibuloplasty was performed. 2 months after removal of the distractor, grafting of the alveolar cleft was carried out with an iliac cancellous bone graft.

Transpalatal distraction osteogenesis surgery

A mucoperiosteal flap was elevated through a gingival incision extending from the distal margin of the ipsilateral first molar to the cleft side. The incision began around the cleft to the other side of the premaxilla. In unilateral cases, the incision continued to the other side of the cleft until it reached the canine on the opposite side. In bilateral cleft, the same incision was used bilaterally as well as elevation of the mucosa over the premaxilla. Osteotomy of the maxillary buccal bone and lateral nasal bone were performed high, away from the roots of the teeth and just below the zygoma. It extended from the lateral nasal wall to the pterygomaxillary fissure without disjunction. The maxillary segment was tested for movement to ensure distraction was possible. In unilateral collapse, the osteotomy stopped at the cleft edge, while in bilateral cases osteotomy was carried out on both sides of the maxilla leaving the premaxilla bone untouched.

After osteotomy, the nasal mucosa was elevated and sutured if possible. In some cases, this was difficult or impossible because of the severe overlap of the premaxilla and the lateral segments. The distractor was then placed in the palate opposite the first premolars with no mucosal incision. The distractor was secured in the palatal bone with a 5–7 mm transmucosal screw. If possible, the oral mucosa on the buccal side was sutured over the defect closing the cleft with soft tissue only.

Alveolar bone grafting

In all cases, bone graft was harvested from the anterior iliac crest through a medial approach with minimal incision. Only cancellous bone chips were harvested. The bone graft was condensed and placed into the reopened cleft. Palatal fistula, if present, was closed at this stage. Soft tissues closure was easy because of the previous distraction and soft tissue procedures. Figure 1 is an example of the sequence of treatment in a unilateral alveolar cleft with unilateral collapsed maxilla.

Fig. 1
(a) Preoperative alveolar cleft with unilateral asymmetry of the maxilla. (b) Operative (distraction) photograph showing lateral osteotomy and sutured nasal mucosa during insertion of the distractor. (c) Transpalatal distraction osteogenesis in place in the first premolar area. (d) Occlusion and soft tissue healing after removal of the distractor and before grafting. (e) Second surgery with cancellous bone graft in the defect. (f) Post-grafting showing healed cleft site.

For each patient, study models were taken prior to distraction and immediately after distractor removal. The maxillary arch width was calculated at three points: canines, first premolars and first molars. The mark point for each tooth was determined by two intersecting lines, a gingival margin line and a line at the midpoint of the mesiodistal width of the tooth. The mean and standard deviation of the inter-arch distance and the percentage of arch width growth were calculated for each of these three points in each cast. Paired t tests were calculated for each of these points to assess the significance of maxillary arch width expansion. To assess bone formation in the cleft area, a periapical and orthopantomogram were taken before and 6 months after grafting. Patients were followed clinically for wound dehiscence, development of infection, persistence of oronasal fistulae, partial or complete loss of the graft, tipping of the maxillary segments and donor side morbidity.

Results

Of the surgical cases, 5 patients presented with bilateral cleft and 6 with unilateral cleft. All patients had had their cleft lip and palate closed early in life and no previous attempt had been made at alveolar cleft closure or grafting. At the time of distraction, the permanent canines of all patients had erupted.

There were no intra-operative complications such as malfracturing or excessive bleeding. In two cases, it was difficult to place the distractor in the first premolar area as the distance was too small to accommodate the smallest available distractor. In these cases, the distractor was initially placed more posteriorly during the first week of active distraction. Another distractor was placed at the first premolar level to achieve more anterior distraction. Patient data are given in Table 1 . The pre- and post-distraction casts were measured twice by the same investigator to ensure measurement accuracy. Paired t tests showed no significant differences between the first and second measurements. The mean inter-arch distance and standard deviation at the canines, first premolars and first molars are shown in Table 2 . In all cases, transpalatal distraction osteogenesis successfully corrected maxillary collapse and cross bite. t tests showed high significance between the pre- and post-distraction inter-arch distances for all measured points. The percentage of arch width improvement was more at the canine (37%), followed by the first premolars (35%) and the first molars (27%).

Table 1
Patient data.
Patient Age Sex Type of cleft Pre-distraction vestibuloplasy Minor graft loss Total graft loss Palatal fistula remained Donor site morbidity Failure of distraction Distractor looseness
1 22 Male Bilateral Mucosal graft vestibuloplasty No No No No No No
2 20 Male Unilateral No No No No No No No
3 19 male Bilateral No No No No No No Yes
4 21 Male Bilateral No yes No No No No No
5 28 Male Unilateral Scar release-z-plasty No No No No No No
6 23 Female Unilateral No No Yes Yes No No Yes
7 15 Male Unilateral No No No No No No No
8 16 Female Bilateral No No No No No No No
9 19 Male Bilateral No No No No No No No
10 16 Female Unilateral Mucosal graft vestibuloplasty No No No No No No
11 18 Male Unilateral No Yes No No No No No
Only gold members can continue reading. Log In or Register to continue

Feb 8, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Transpalatal distraction osteogenesis prior to alveolar bone grafting in cleft lip and palate patients
Premium Wordpress Themes by UFO Themes