J. Cranio-Max.-Fac.Surg. 19 (1991) j. Cranio-Max.-Fac.Surg. 19 (1991) 153-154 © GeorgThiemeVerlagStuttgart • New York

Pterygoid Plate Separation Using an Oscillating Saw in Le Fort I Osteotomy

153

Summary An oscillating saw is used to achieve pterygomaxillary separation. The procedure is quick and simple to perform and avoids the potentially hazardous use of osteotomes for this purpose. Down fracture of the maxilla allows visual confirmation of the integrity of the pterygoid plates.

Technical Note

Key words

Richard P. Juniper 1, Zoran Staj~i82

Le Fort I Osteotomy - Interpterygo - Maxillary separation

i Dept. of Oral and MaxillofacialSurgery(Consultants:J. Rayne,M.A., D. Phil., D. Orth., F. D. S.R. C. S. [Eng.];R. P. Juniper,M. B.B.S., B.D. S., F. D. S.R. C. S. [Eng.]),John RadcliffeHospital, Oxford,UnitedKingdom 2Oral SurgeryClinic(Head: Prof.B.Jojic, D. D. S., PhD.),Facultyof Stomatology,Universityof Beograd,Yugoslavia Submitted 30.7. 1990; accepted 28.1. 1991

Introduction Le Fort I (low level maxillary) osteotomy has become a common procedure in the treatment of dentofacial deformities. Separation of the maxilla from the pterygoid plates must be achieved before down fracture of the maxilla can be accomplished. The various techniques described in the past involve the creation of a fracture in the pterygomaxillary region by the use of an osteotome via a blind approach. Force directed incorrectly at the pterygomaxillary junction can cause undesirable fractures to occur. This may hazard the procedure and more significantly may result in increased morbidity. Unfavourable fractures have been shown to occur experimentally both on dried human skulls (Wikkeling and Koppendraaier, 1973; Hiranuma et al., 1988) and cadavers (Robinson and Hendy, 1986; Staj~iS, 1990). To avoid such unfavourable fractures there have been attempts either to modify the technique by inserting a straight osteotome extraorally (Du Pont et al., 1974) or intraorally through the maxillary tuberosity (Trimble et al., 1983) or to design a new instrument (Wikkeling and Tacoma, 1975). This report describes a technique in which an oscillating saw is used to cut through the pterygomaxillary junction.

Discussion It has been shown that, regardless of the type of osteotome being used, fractures of the pterygoid plates are likely to occur due to the large compressive stress at final separation (Hiranuma et al., 1988). The unpredictable nature of the so-called high level pterygoid plate fractures (Robinson and Hendy, 1986) has been assumed to be responsible for severe and possibly life-threatening haemorrhages in Le Fort I osteotomies (Newhouse et al., 1982; Lanigan and West, 1984). The technique described has been applied in six Le Fort I osteotomies. Pterygoid plates were routinely inspected after the maxilla had been downfractured and fully mobilised, and found to be intact. Thus, separating the pterygoid plates with an oscillating saw offers advantages over standard procedures using a chisel. The thin oscillating blade is unlikely to impart any compressive stress on the pterygoid plates sufficient to cause fracture. This should avoid any of the serious complications which have been reported. Furthermore the technique can easily be applied using the usual incision without any risk of palatal laceration or exposure of the buccal fat pad.

/

Technique After the lateral wall of the maxilla, lateral nasal wall and nasal septum have been cut, a right angled oscillating saw is introduced through the subperiosteal tunnel, with the blade placed onto the pterygomaxillary junction (Fig. 1). The one centimetre blade of the Stryker oscillating saw (designed for the vertical subsigmoid mandibular osteotomy) is ideal. The upper edge of the blade is placed at the level of the lateral osteotomy cut. By cutting through the bone the blade is aimed downwards and medially towards the arch of the palate adjacent to the last molar tooth. The completion of the osteotomy is confirmed by palpation of the vibrating saw through the intact mucosa.

Fig. 1 The one centimetre blade of the rightangled Stryker oscillating saw is introduced through the subperiosteal tunnel and placed onto the pterygomaxillary junction. When cutting through the bone the blade is aimed downwards and medially towards the arch of the palate adjacent to the last molar tooth.

154

J. Cranio-Max.-Fac. Surg. 19 (1991)

Acknowledgements This study was supported by the British Council ALIS grant and in part by a grant from the Serbian Research Fund.

References Du Pont, C., H. Ciaburro, ¥. Prevost: Simplifying the Le Fort I type of maxillary osteotomy. Plastic. Reconstr. Surg. 54 (1974) 142 Hiranuma, ¥., Y. Yamamoto, T. Iizuka: Strain distribution during separation of the pterygomaxillarysuture by osteotomes. Comparison between Obwegeser's osteotome and swan's neck osteotome. J. Cranio-Max.-Fac. Surg. 16 (1988) 13 Lanigan, D. T., R. A. West: Management of postoperative hemorrhage following the Le Fort I maxillary osteotomy. J. Oral Maxillofac. Surg. 42 (1984) 367 Newhouse, R. F., S. R. Schow, R~ A. Kraut, J. C. Pricw: Life-threatening hemorrhage form a Le Fort I osteotomy. J. Oral Maxillofac. Surg. 40 (]982) 117 Robinson, P. P., C. W. Hendy: Pterygoid plate fractures caused by the Le Fort I osteotomy. Br. J. Oral Maxillofac. Surg. 24 (1986) 198 Staj~i~, Z.: Mtering the angulation of a curved osteotome - does it have effects on the type of the pterygomaxillary disjunction in Le Fort I osteotomy: Int. J. Oral Maxillofac. Surg. (1990) submitted.

R. P. Juniper, z. Staj~i8: Pterygoid Plate Separation Trimble, L. D., H. Tideman, P. J. W. Stoelinga: A modification of the pterygoid plate separation in low-level maxillary osteotomies. J. Oral Maxillofac. Surg. 41 (1983) 544 Wikkeling~ O. M. E., J. Koppendraaier: Ill vitro studies on lines of osteotomy in the pterygoid region. J. Max.-Fac. Surg. 1 (1973) 209 Wikkeling, O. M. E., J. Tacoma: Osteotomy of the pterygomaxillary junction. Int. J. Oral Surg. 4 (1975) 99

Dr. R. P. Juniper John Radcliffe Hospital Dept. Oral and Maxillofacial Surgery Oxford OX3 9DU United Kingdom Dr. Z. Staj~i8 Oral Surgery Clinic Faculty of Stomatology, FAH 506 11000 Beograd Yugoslavia

Pterygoid plate separation using an oscillating saw in Le Fort I osteotomy. Technical note.

An oscillating saw is used to achieve pterygomaxillary separation. The procedure is quick and simple to perform and avoids the potentially hazardous u...
144KB Sizes 0 Downloads 0 Views