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The role of intraoperative ultrasonography in zygomatic complex fracture repair
Int. J. Oral Maxillofac. Surg. 2006; 35: 224–230 doi:10.1016/j.ijom.2005.10.005, available online at http://www.sciencedirect.com
Clinical Paper Trauma
The role of intraoperative ultrasonography in zygomatic complex fracture repair
D. Gu¨licher, M. Krimmel, S. Reinert Department of Oral and Maxillofacial Surgery, University Hospital Tu¨bingen, Germany
D. Gu¨licher, M. Krimmel, S. Reinert: The role of intraoperative ultrasonography in zygomatic complex fracture repair. Int. J. Oral Maxillofac. Surg. 2006; 35: 224–230. # 2005 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. Intraoperative assessment of the zygomatic arch is very important in achieving adequate repositioning. The correct alignment of the zygomatic arch indicates the proper position of the zygomatic bone and ensures adequate prominence of the lateral midfacial aspect. The aim of this study was to estimate the value of ultrasonography as an intraoperative repositioning control. In a clinical study of 25 patients, ultrasonography was employed for intraoperative visualization of the zygomatic arch before and after fracture repositioning. Twelve patients presented with isolated zygomatic arch fractures and 13 with combined fractures of the zygomatic bone and arch. The ultrasonographic findings were compared to the radiological and clinical findings. Ultrasonography was able to detect all fractures and dislocations of the zygomatic arch. It was possible to assess the repositioning in 24 out of 25 cases using ultrasonography. The ultrasound images were concordant with the radiographs. Clinical assessment by palpation only succeeded in isolated zygomatic arch fractures with an m-shaped impression, whereas it remained uncertain in nearly all cases with a different dislocation pattern. Ultrasonography was rapid and easy to perform, and is recommended as an intraoperative visualizing tool in all midfacial fractures with displacement of the zygomatic arch.
In midfacial fracture repair the alignment of the zygomatic arch is very important. The contour of the zygomatic arch reflects the relationship of the zygomatic bone to the skull base, and is the most reliable indicator of the anterior projection of the zygoma11,21. Assessment of the position of the zygoma at additional fracture sites (i.e. the zygomaticofrontal process, the infraorbital rim and the zygomaticomaxillary buttress) without taking the zygomatic arch into account may not be 0901-5027/030224 + 07 $30.00/0
sufficient in many cases. Displacement around a vertical rotation axis with posterior inward or outward rotation of the zygoma might remain unrecognized. In comminuted fractures the assessment of repositioning is even more difficult. Consolidation of the zygoma in a malposition results in facial asymmetry with reduced sagittal prominence and increased transversal width of the midface. The persisting dislocation of the zygomatic arch itself might lead to a visible depression of the
Keywords: zygomatic complex fractures; zygomatic arch; ultrasonography; intraoperative assessment. Accepted for publication 19 October 2005 Available online 20 December 2005
overlying soft tissues, and the zygomatic arch might interfere with the mandibular ramus resulting in limitation of mouth opening. Finally, an incomplete reposition might be unstable and bears the risk of redisplacement. Therefore, during midfacial fracture repair, the contour of the zygomatic arch should be assessed intraoperatively whenever a displacement of the zygomatic arch is evident. Options for intraoperative control of the zygomatic arch comprise
# 2005 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
The role of intraoperative ultrasonography in zygomatic complex fracture repair
225
Table 1. Patients with isolated zygomatic arch fractures: radiological, clinical and ultrasonographic findings of the zygomatic arch contour before and after repositioning Radiology Patients (sex-age) M-30.9 M-48.1 M-23.7 M-35.4 M-53.6 M-32.9 M-29.7 M-28.5 F-37.7 F-19.6 M-56.9 M-43.2
Palpation
Ultrasonography
Radiology
Zygomatic arch fracture type
Fracture assessment
Reposition assessment
Fracture assessment
Reposition assessment
. . . Leading to further reposition
Reposition result
m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression Posterior fragment Posterior fragment Intermediate fragment Intermediate fragment
Sufficient Sufficient Sufficient Sufficient Uncertain Sufficient Sufficient Sufficient Insufficient Insufficient Insufficient Insufficient
Sufficient Sufficient Sufficient Sufficient Uncertain Uncertain Sufficient Sufficient Insufficient Insufficient Insufficient Insufficient
Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient
Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Insufficient
No Yes No No Yes No No No Yes No Yes Yes
Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete Adequate Partial
transcutaneous palpation, radiological visualization using a c-bow9 or even a mobile computed tomography (CT) scanner13, endoscopic visualization via different small incisions2,16 and exposure via a coronal approach4,11,21. Another option is ultrasonographic visualization, a technique introduced by AKIZUKI et al. in 19901. FRIEDRICH & VOLK9 ENSTEIN used ultrasonography for pre- and postoperative examination of 15 patients with zygomatic arch fractures. The authors elaborated the ultrasonographic fracture criteria, and interventional use in the operation theatre was described for a few patients. FRIEDRICH & VOLKENSTEIN recommended ultrasonography only for isolated zygomatic arch fractures. Recent studies have dealt with the role of ultrasonography in diagnosing fractures in different regions of the face. Ultrasonography has proved to be a valuable tool in detecting fractures at the zygomaticofrontal process, the lateral wall of the maxillary sinus, the zygomatic arch and the orbital floor7,12,14,15. In the diagnosis of mandibular fractures ultrasonography has
been less successful, with a considerable number of fractures remaining undetected8. Studies assessing the potential of ultrasonography as an intraoperative tool for repositioning control are however missing from the recent literature. The aims of this prospective investigation were 1. evaluation of the benefit of intraoperative ultrasonography in fracture repair of the zygomatic complex, with special regard to combined fractures, complex dislocation and extensive soft-tissue swelling, 2. comparison of the ultrasonographic findings with the clinical and radiological examinations, and 3. assessment of the time and costs involved in the intraoperative use of ultrasonography.
Patients and methods
Ultrasonography was employed for the intraoperative visualization of the zygomatic arch in 25 patients with zygomatic
complex fractures between February 2003 and August 2004. There were 3 women and 22 men with a mean age of 38 years (19.6–56.9 years). Twelve patients had isolated fractures of the zygomatic arch (Table 1) and 13 had combined fractures of zygomatic bone and arch (Table 2). All the fractures were diagnosed by conventional radiographs or CT scan. Six patients with isolated zygomatic arch fractures only had conventional plane radiographs, whereas the remaining 6 and all the patients with combined fractures had a helical CT scan. The type of displacement was categorized according to the recommendations of ROWE & WILLIAMS19 (Figs 1 and 2). The degree of displacement required surgical therapy in all cases, and this was performed between 0 and 23 days after the trauma. The isolated zygomatic arch fractures were operated on as soon as possible, the median delay being 2 days (0–12 days). The combined fractures were operated on after the swelling had partially resolved, with a median delay of 7 days (3–23 days). Either the 1st or the 2nd author of this paper performed
Table 2. Patients with combined fractures of zygomatic bone and arch: radiological, clinical and ultrasonographic findings of the zygomatic arch contour before and after repositioning Radiology Patients (sex-age) M-51.5 M-47.2 M-34.7 M-42.8 M-40.1 F-29.6 M-34.3 M-32.3 M-44.2 M-49.1 M-29.2 M-40.7 M-34.7
Palpation
Ultrasonography
Radiology
Zygomatic arch fracture type
Fracture assessment
Reposition assessment
Fracture assessment
Reposition assessment
. . . Leading to further reposition
Reposition result
m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression Intermediate fragment Step Step Step Step Step Intermediate fragment
Insufficient Insufficient Insufficient Sufficient Insufficient Insufficient Insufficient Insufficient Uncertain Insufficient Sufficient Sufficient Insufficient
Insufficient Insufficient Uncertain Sufficient Sufficient Uncertain Insufficient Insufficient Uncertain Uncertain Insufficient Uncertain Insufficient
Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient
Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient
No No No Yes No No No Yes Yes No Yes Yes Yes
Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete
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Fig. 1. Dislocation pattern of isolated zygomatic arch fractures. Left: m-shaped impression; middle: impressed posterior arch fragment; right: medially dislocated intermediate fragment.
Fig. 2. Dislocation pattern of combined fractures of zygomatic bone and arch. Rotational dislocation of zygomatic bone around vertical axis: left: with m-shaped impression of zygomytic arch; middle: with step of zygomatic arch; right: with medial dislocation of intermediate fragment.
the operations including the ultrasonographic examinations. The isolated zygomatic arch fractures were reduced without exposition of the fracture sites using a bent hook with a sharp end. It was inserted via a stab incision placed 3 cm below the arch19. In the patients with combined fractures, the fracture sites were exposed via a lateral eyebrow, a subciliary and/or a buccal sulcus incision. The zygomatic bone was reduced with a transcutaneously inserted hook and stabilized using miniplate osteosynthesis. The zygomatic arch was reduced separately, if necessary. For the ultrasonographic examinations, a Siemens Elegra1 Ultrasound System with 2 broadband linear transducers (Siemens VFX13.5 or 7.5L40) was employed. The frequency was set between 7.5 and 12 MHz depending on the image quality to be achieved. For interventional use under sterile conditions the transducer was coated with a sterile endoscope covering. An incision foil covered the coupling plane (Fig. 3). A commercially available sterile gel (Instillagel1) was used. The zygomatic arch was visualized in 2 per-
pendicular planes with the transducer applied to the skin horizontally (Fig. 4) and vertically. Before and after the reduction manoeuvres the zygomatic arch contour was assessed by ultrasonography and
by palpation. Postoperatively, all patients received plane radiographs for reposition control. The achieved result was judged ‘complete’ if the fractured zygomatic bone and/or arch were in an anatomically
Fig. 3. Sterile coated transducer for intraoperative use.
The role of intraoperative ultrasonography in zygomatic complex fracture repair
Fig. 4. Intraoperative ultrasonography: transducer held parallel to long axis of the zygomatic arch.
correct position, and ‘adequate’ if there were minor discrepancies without clinical relevance remaining in the fragment positions. The result was judged ‘partial’ if at least 1 fragment presented with a markedly false position. Results
The results are summarized in Tables 1 and 2. The isolated zygomatic arch fractures showed a typical m-shaped displacement of 2 fragments in 8 patients, and the impression of a singular posterior or intermediate fragment in 2 patients respectively,
(Table 1, Fig. 1). In all the patients with combined fractures there was a rotational displacement of the zygomatic bone around a vertical rotation axis (Fig. 5), along with an m-shaped impression of the zygomatic arch in 6 patients, a step of the zygomatic arch in 5 patients and an impression of an intermediate arch fragment in the remaining 2 patients (Table 2, Fig. 2). The displacement of the zygomatic arch could be visualized by ultrasonography in all 25 cases. The ultrasound images were always concordant with the radiological findings. Palpation was sufficient in only 10 patients, 7 of whom were suffering
Fig. 5. 3D reconstruction from CT scan of patient M-51.5, visualizing the typical displacement of the zygomatic bone with rotation around a vertical rotation axis.
227
from isolated zygomatic arch fractures with m-shaped displacement. After repositioning, the alignment of the zygomatic arch could be correctly assessed by ultrasonography in 24 patients; in the remaining patient the arrangement of the fragments was misinterpreted on the ultrasound images. The repositioning of 7 isolated zygomatic arch fractures with mshaped dislocation could be assessed by palpation alone, whereas for the combined fractures palpation turned out to be uncertain in all but 1 patient. The intraoperative ultrasonography revealed 5 isolated zygomatic arch fractures and 7 combined fractures to be reduced incompletely. This prompted the surgeon to exert further repositioning efforts on the zygomatic bone and/or arch. The final ultrasonographic control showed the zygomatic arch to be well aligned in 24 out of 25 patients. The postoperative radiographs confirmed these results showing the zygomatic bone and/or arch with an anatomically correct or nearly correct position and projection (judged ‘complete’ or ‘adequate’) in 24 patients. Two clinical examples are presented in Figs 6 and 7. The patient in whom ultrasonographic examination had been insufficient only received an acceptable repositioning result (judged ‘partial’). Discussion
Displaced fractures of the zygomatic complex with disruption of the zygomatic arch contour require intraoperative control of the zygomatic arch. In isolated zygomatic arch fractures the surgeon must be assured of sufficient repositioning, because only the complete repositioning of the zygomatic arch has proved to be stable due to fragment interlocking22. In patients with zygomatic bone fractures the correct alignment of the zygomatic arch ensures sufficient sagittal projection of the zygomatic complex and prevents broadening of the facial width. A compressed zygomatic arch or an intermediate arch fragment not fitting into the gap indicates that the lateral part of the zygomatic body is displaced posteriorly. The zygomatic arch is thus considered the key in complex midfacial fracture repair11. The exposed fracture sites at the lateral and inferior orbital rim3 do not reflect the position of the zygomatic bone adequately, as correct alignment in these regions may be accompanied by an unrecognized distinct impression of the lateral part of the bone4,21. The sphenozygomatic suture is a valuable region for repositioning assessment, but also fails to indicate a false position at its
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Fig. 6. Patient F-37.7 with isolated zygomatic arch fracture: (a) CT scan and (b) ultrasound image. Result of repositioning: (c) ultrasound image and (d) radiograph.
lateral end. Assessment of the zygomaticomaxillary buttress is often uncertain, too, due to a comminuted fracture at this site21, and it requires an additional surgical approach, which would otherwise usually be considered nonessential. If an isolated zygomatic arch fracture with m-shaped dislocation is treated, repositioning is frequently associated with a definite fragment movement and a tangible clicking indicating interlocking of the fragments22. In these cases transcutaneous palpation is satisfactory as an intraoperative reduction control. In 9 of our patients with m-shaped arch displacement (7 with an isolated arch fracture, 2 with a combined fracture), sufficient zygomatic arch alignment could also be proved by palpation alone, the additional ultrasound images serving as confirmation. In isolated zygomatic arch fractures with a different kind of displacement and with only 1 impressed fragment or with a missing interfragmentary contact, the repositioning movement is not so clearly detectable.
In patients with combined fractures, it is the more complex fracture pattern with several fragments being in a false position and the soft-tissue swelling persisting at the operation date that complicate the clinical evaluation. For these reasons, assessment of the repositioning by palpation was not sufficient in 4 patients with isolated zygomatic arch fractures and in 9 with combined fractures in the present study. An additional technique for intraoperative examination is evidently necessary. The radiological visualization of the zygomatic arch using a c-bow is difficult to achieve9, and exposes the patient and staff to irradiation. The intraoperative CT scan is not widely available, as it requires a mobile CT scanner operated by a radiologist13. The endoscope inserted through temporal, preauricular or intraoral incisions enables repositioning with a direct view of the zygomatic arch2,16; as the fracture sites are exposed osteosynthesis of the zygomatic arch is possible, too.
Endoscopic visualization of the zygomatic arch is however a technically demanding and time-consuming process; palsy of facial nerve branches, temporal hollowing and necrosis of the zygomatic arch may occur, and osteosynthesis is only rarely required4,22. The coronal approach to the zygomatic arch is highly invasive with considerable shortcomings2,11,16, and is thus restricted to complex trauma with the need for multiple osteosyntheses4,11,21. Ultrasonography is easy and quick to perform; it is noninvasive and free of any risks. The possibility of ultrasonographic fracture visualization in the midface has already been described elsewhere6,7,15,17,18. Through the development of modern ultrasound systems former disadvantages of the technique have been overcome. Transducers working with high frequencies up to 12 MHz shorten the focus to superficial regions, so that the use of a water-filled conductor, as recommended by AKIZUKI et al.1, is no longer
The role of intraoperative ultrasonography in zygomatic complex fracture repair
229
Fig. 7. Patient M-51.5 with combined fracture of zygomatic bone and arch: (a) CT scan and (b) ultrasound image. Result of repositioning: (c) ultrasound image and (d) radiograph. The small persistent displacement of the intermediate zygomatic arch fragment is clearly visible in both the ultrasound image and the radiograph.
necessary. Modern linear transducers receive additional ultrasound signals from the peripheral sectors of the examined region which can be used for image formation; the visualized area is thus enlarged and the physician is able to see almost the whole zygomatic arch on 1 screenshot, which simplifies the assessment of its contour9. Analysis of harmonic ultrasound frequencies (Tissue Harmonic Imaging1)20 improves image quality so that even slim bones such as the zygomatic arch are visualized with high contrast. The enhanced lateral solution enables the detection of the smallest dislocations. Using ultrasonography in a comparative study, MCCANN et al.18 were able to detect zygomatic arch fractures which remained obscure in the radiographs of 4 out of 22 patients. The application of a sterile coating makes the intraoperative use of the transducer easy. Expensive gas sterilization of the transducer1 or cover-
ing of the entire surgical area with a sterile foil9 may be abandoned. Adjustment of the system before surgery starts reduces the time required intraoperatively for the sonographic examination and avoids the need for intraoperative access to the keyboard. Finally, innovative algorithms enable the sonographic examination under daylight conditions5 making the darkening of the operation theatre unnecessary. In the present study all 25 zygomatic arch fractures were clearly detected by ultrasonography. The sensitivity and positive predictive value of fracture diagnosis were both 100%. These results confirm this method to be a useful visualizing tool for fractures of the zygomatic arch regardless of the type of displacement10. MCCANN et al.18 stated that a gross swelling and emphysema make the ultrasonographic visualization of bony surfaces difficult or even impossible. The problem
of an extensive swelling was overcome in the present study by choosing an ultrasound frequency of 7.5 MHz or less and by using the harmonic imaging function. Due to the enhancement of contrast and of lateral solution, the image quality was sufficient, although the ultrasound waves had to penetrate a thick layer of soft tissue. Emphysema was not really a problem in the zygomatic arch region, as it occurred predominantly in direct contact with the fractured sinus walls. After the repositioning manoeuvres, assessment of the reduced zygomatic arch with ultrasonography was sufficient in all but 1 case. In the combined fractures, visualization of the zygomatic arch not only proved its correct alignment but also confirmed the proper antero-posterior projection of the zygomatic bone. In contrast, manual palpation succeeded only in isolated zygomatic arch fractures with an m-shaped dislocation; assessment
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remained uncertain in the other fracture patterns for the above-mentioned reasons. Another factor impeding palpation was the elevation of the zygomatic arch under local anaesthesia used in 2 patients. The infiltration of about 8 ml anaesthetic into the soft tissues surrounding the zygomatic arch resulted in an additional swelling. Palpation became uncertain whereas the ultrasonographic examination still worked well giving adequate repositioning control. In a considerable number of cases ultrasonography detected the remaining displacements which palpation was not able to detect. This resulted in further repositioning efforts, either the revision of the position of the zygomatic bone or the additional repositioning of the zygomatic arch. In addition, ultrasonographic visualization facilitated the positioning of the reposition instrument beneath the fragments. Fracture repair under ultrasonographic control led to excellent results in 24 out of 25 patients. The final ultrasound images corresponded exactly to the postoperative radiographs. In the 25th patient, the surgeon failed to assess the zygomatic arch contour correctly using ultrasonography: multiple echoes superficial to the zygomatic arch confused the image interpretation. The posterior fragment had a sharp end which was positioned laterally to the anterior fragment. This remaining displacement was not so clearly visible in the ultrasound images, such that the surgeon deemed the reposition to be adequate. The benefit of intraoperative ultrasonography in optimizing the repositioning of the zygomatic complex is evident. The technique is easy to perform. The examination requires only about 10 min. The sterile coating costs no more than s5. Only in isolated zygomatic arch fractures with an m-shaped impression is ultrasonography unnecessary if the reposition and the interlocking of the fragments are clearly palpable. In all other kinds of displacement (Fig. 6), and especially in the combined fractures of zygomatic bone and arch (Fig. 7), ultrasonography seems to be the best visualizing tool for intraoperative repositioning control, enabling the surgeon to assess both the alignment of the zygomatic arch and the facial projection of the zygomatic body. Ultrasono-
graphy should become an inherent part of zygomatic complex fracture repair. 13.
References 1. Akizuki H, Yoshida H, Michi K. Ultrasonographic evaluation during reduction of zygomatic arch fractures. J Craniomaxillofac Surg 1990: 18: 263–266. 2. Chen CT, Lai JP, Chen YR, Tung TC, Chen ZC, Rohrich RJ. Application of endoscope in zygomatic fracture repair. Br J Plast Surg 2000: 53: 100–105. 3. Covington DS, Wainwright DJ, Teichgraeber JF, Parks DH. Changing patterns in the epidemiology and treatment of zygoma fractures: 10-year review. J Trauma 1994: 37: 243–248. 4. Ellis III E, Reddy L. Status of the internal orbit after reduction of zygomaticomaxillary complex fractures. J Oral Maxillofac Surg 2004: 62: 275–283. 5. Fischer T, Filimonow S, Taupitz M, Petersein J, Beyersdorff D, Bollow M, Hamm B. Image quality and detection of pathology by ultrasound: comparison of B-mode ultrasound with photopic imaging and tissue harmonic imaging alone and in combination. Rofo 2002: 174: 1313–1317. 6. Forrest CR, Lata AC, Marcuzzi DW, Bailey MH. The role of orbital ultrasound in the diagnosis of orbital fractures. Plast Reconstr Surg 1993: 92: 28–34. 7. Friedrich RE, Heiland M, BartelFriedrich S. Potentials of ultrasound in the diagnosis of midfacial fractures. Clin Oral Investig 2003: 7: 226–229. 8. Friedrich RE, Plambeck K, BartelFriedrich S, Giese M, Schmelzle R. Limitations of B-scan ultrasound for diagnosing fractures of the mandibular condyle and ramus. Clin Oral Invest 2001: 5: 11–16. 9. Friedrich RE, Volkenstein RJ. The value of ultrasonography in the diagnosis of zygomatic arch fractures [in German]. Dtsch Z Mund Kiefer Gesichtschir 1991: 15: 472–479. 10. Friedrich RE, Volkenstein RJ. Diagnosis and follow-up of reduction of fractures of the zygomatic arch [in German]. Ultraschall Med 1994: 15: 213–216. 11. Gruss JS, Van-Wyck L, Phillips JH, Antonyshyn O. The importance of the zygomatic arch in complex midfacial fracture repair and correction of posttraumatic orbitozygomatic deformities. Plast Reconstr Surg 1990: 85: 878–890. 12. Hirai T, Manders EK, Nagamoto K, Saggers GC. Ultrasonic observation of
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facial bone fractures: report of cases. J Oral Maxillofac Surg 1996: 54: 776– 779. Hoffmann J, Krimmel M, Dammann F, Reinert S. Feasibility of intraoperative diagnosis with a mobile computed tomography scanner [in German]. Mund Kiefer Gesichtschir 2002: 6: 346–350. Jank S, Emshoff R, Etzelsdorfer M, Strobl H, Nicasi A, Norer B. The diagnostic value of ultrasonography in the detection of orbital floor fractures with a curved array transducer. Int J Oral Maxillofac Surg 2004: 33: 13–18. Jenkins CN, Thuau H. Ultrasound imaging in assessment of fractures of the orbital floor. Clin Radiol 1997: 52: 708–711. Krimmel M, Cornelius CP, Reinert S. Endoscopically assisted zygomatic fracture reduction and osteosynthesis revisited. Int J Oral Maxillofac Surg 2002: 31: 485–488. Lata AC, Marcuzzi DW, Forrest CR. Comparison of real-time ultrasonography and coronal computed tomography in the diagnosis of orbital fractures. Can Assoc Radiol J 1993: 44: 371–376. McCann PJ, Brocklebank LM, Ayoub AF. Assessment of zygomatico-orbital complex fractures using ultrasonography. Br J Oral Maxillofac Surg 2000: 38: 525– 529. Rowe NL, Williams JL, Fractures of the zygomatic complex and orbit. In: Williams JL, ed: Rowe and Williams’ Maxillofacial injuries, Vol I. Edinburgh: Churchill Livingstone 1994: 475–490. Schoelgens C. Improved B-image diagnosis with harmonic imaging [in German]. Ultraschall Med 1998: 19: M70– M75. Stanley Jr RB. The zygomatic arch as a guide to reconstruction of comminuted malar fractures. Arch Otolaryngol Head Neck Surg 1989: 115: 1459–1462. van-der-Wal KG, de-Visscher JG. Fixation of the unstable zygomatic arch fracture. J Oral Surg 1981: 39: 783– 784.
Address: Dirk Gu¨licher, Department of Oral and Maxillofacial Surgery, University Hospital Tu¨bingen, Osianderstraße 2-8, D-72076 Tu¨bingen, Germany. Tel: +49 7071 2986174; Fax: +49 7071 295449. E-mail: [email protected]
Clinical Paper Trauma
The role of intraoperative ultrasonography in zygomatic complex fracture repair
D. Gu¨licher, M. Krimmel, S. Reinert Department of Oral and Maxillofacial Surgery, University Hospital Tu¨bingen, Germany
D. Gu¨licher, M. Krimmel, S. Reinert: The role of intraoperative ultrasonography in zygomatic complex fracture repair. Int. J. Oral Maxillofac. Surg. 2006; 35: 224–230. # 2005 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. Intraoperative assessment of the zygomatic arch is very important in achieving adequate repositioning. The correct alignment of the zygomatic arch indicates the proper position of the zygomatic bone and ensures adequate prominence of the lateral midfacial aspect. The aim of this study was to estimate the value of ultrasonography as an intraoperative repositioning control. In a clinical study of 25 patients, ultrasonography was employed for intraoperative visualization of the zygomatic arch before and after fracture repositioning. Twelve patients presented with isolated zygomatic arch fractures and 13 with combined fractures of the zygomatic bone and arch. The ultrasonographic findings were compared to the radiological and clinical findings. Ultrasonography was able to detect all fractures and dislocations of the zygomatic arch. It was possible to assess the repositioning in 24 out of 25 cases using ultrasonography. The ultrasound images were concordant with the radiographs. Clinical assessment by palpation only succeeded in isolated zygomatic arch fractures with an m-shaped impression, whereas it remained uncertain in nearly all cases with a different dislocation pattern. Ultrasonography was rapid and easy to perform, and is recommended as an intraoperative visualizing tool in all midfacial fractures with displacement of the zygomatic arch.
In midfacial fracture repair the alignment of the zygomatic arch is very important. The contour of the zygomatic arch reflects the relationship of the zygomatic bone to the skull base, and is the most reliable indicator of the anterior projection of the zygoma11,21. Assessment of the position of the zygoma at additional fracture sites (i.e. the zygomaticofrontal process, the infraorbital rim and the zygomaticomaxillary buttress) without taking the zygomatic arch into account may not be 0901-5027/030224 + 07 $30.00/0
sufficient in many cases. Displacement around a vertical rotation axis with posterior inward or outward rotation of the zygoma might remain unrecognized. In comminuted fractures the assessment of repositioning is even more difficult. Consolidation of the zygoma in a malposition results in facial asymmetry with reduced sagittal prominence and increased transversal width of the midface. The persisting dislocation of the zygomatic arch itself might lead to a visible depression of the
Keywords: zygomatic complex fractures; zygomatic arch; ultrasonography; intraoperative assessment. Accepted for publication 19 October 2005 Available online 20 December 2005
overlying soft tissues, and the zygomatic arch might interfere with the mandibular ramus resulting in limitation of mouth opening. Finally, an incomplete reposition might be unstable and bears the risk of redisplacement. Therefore, during midfacial fracture repair, the contour of the zygomatic arch should be assessed intraoperatively whenever a displacement of the zygomatic arch is evident. Options for intraoperative control of the zygomatic arch comprise
# 2005 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
The role of intraoperative ultrasonography in zygomatic complex fracture repair
225
Table 1. Patients with isolated zygomatic arch fractures: radiological, clinical and ultrasonographic findings of the zygomatic arch contour before and after repositioning Radiology Patients (sex-age) M-30.9 M-48.1 M-23.7 M-35.4 M-53.6 M-32.9 M-29.7 M-28.5 F-37.7 F-19.6 M-56.9 M-43.2
Palpation
Ultrasonography
Radiology
Zygomatic arch fracture type
Fracture assessment
Reposition assessment
Fracture assessment
Reposition assessment
. . . Leading to further reposition
Reposition result
m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression Posterior fragment Posterior fragment Intermediate fragment Intermediate fragment
Sufficient Sufficient Sufficient Sufficient Uncertain Sufficient Sufficient Sufficient Insufficient Insufficient Insufficient Insufficient
Sufficient Sufficient Sufficient Sufficient Uncertain Uncertain Sufficient Sufficient Insufficient Insufficient Insufficient Insufficient
Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient
Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Insufficient
No Yes No No Yes No No No Yes No Yes Yes
Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete Adequate Partial
transcutaneous palpation, radiological visualization using a c-bow9 or even a mobile computed tomography (CT) scanner13, endoscopic visualization via different small incisions2,16 and exposure via a coronal approach4,11,21. Another option is ultrasonographic visualization, a technique introduced by AKIZUKI et al. in 19901. FRIEDRICH & VOLK9 ENSTEIN used ultrasonography for pre- and postoperative examination of 15 patients with zygomatic arch fractures. The authors elaborated the ultrasonographic fracture criteria, and interventional use in the operation theatre was described for a few patients. FRIEDRICH & VOLKENSTEIN recommended ultrasonography only for isolated zygomatic arch fractures. Recent studies have dealt with the role of ultrasonography in diagnosing fractures in different regions of the face. Ultrasonography has proved to be a valuable tool in detecting fractures at the zygomaticofrontal process, the lateral wall of the maxillary sinus, the zygomatic arch and the orbital floor7,12,14,15. In the diagnosis of mandibular fractures ultrasonography has
been less successful, with a considerable number of fractures remaining undetected8. Studies assessing the potential of ultrasonography as an intraoperative tool for repositioning control are however missing from the recent literature. The aims of this prospective investigation were 1. evaluation of the benefit of intraoperative ultrasonography in fracture repair of the zygomatic complex, with special regard to combined fractures, complex dislocation and extensive soft-tissue swelling, 2. comparison of the ultrasonographic findings with the clinical and radiological examinations, and 3. assessment of the time and costs involved in the intraoperative use of ultrasonography.
Patients and methods
Ultrasonography was employed for the intraoperative visualization of the zygomatic arch in 25 patients with zygomatic
complex fractures between February 2003 and August 2004. There were 3 women and 22 men with a mean age of 38 years (19.6–56.9 years). Twelve patients had isolated fractures of the zygomatic arch (Table 1) and 13 had combined fractures of zygomatic bone and arch (Table 2). All the fractures were diagnosed by conventional radiographs or CT scan. Six patients with isolated zygomatic arch fractures only had conventional plane radiographs, whereas the remaining 6 and all the patients with combined fractures had a helical CT scan. The type of displacement was categorized according to the recommendations of ROWE & WILLIAMS19 (Figs 1 and 2). The degree of displacement required surgical therapy in all cases, and this was performed between 0 and 23 days after the trauma. The isolated zygomatic arch fractures were operated on as soon as possible, the median delay being 2 days (0–12 days). The combined fractures were operated on after the swelling had partially resolved, with a median delay of 7 days (3–23 days). Either the 1st or the 2nd author of this paper performed
Table 2. Patients with combined fractures of zygomatic bone and arch: radiological, clinical and ultrasonographic findings of the zygomatic arch contour before and after repositioning Radiology Patients (sex-age) M-51.5 M-47.2 M-34.7 M-42.8 M-40.1 F-29.6 M-34.3 M-32.3 M-44.2 M-49.1 M-29.2 M-40.7 M-34.7
Palpation
Ultrasonography
Radiology
Zygomatic arch fracture type
Fracture assessment
Reposition assessment
Fracture assessment
Reposition assessment
. . . Leading to further reposition
Reposition result
m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression m-Shaped impression Intermediate fragment Step Step Step Step Step Intermediate fragment
Insufficient Insufficient Insufficient Sufficient Insufficient Insufficient Insufficient Insufficient Uncertain Insufficient Sufficient Sufficient Insufficient
Insufficient Insufficient Uncertain Sufficient Sufficient Uncertain Insufficient Insufficient Uncertain Uncertain Insufficient Uncertain Insufficient
Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient
Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient Sufficient
No No No Yes No No No Yes Yes No Yes Yes Yes
Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete Complete
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Fig. 1. Dislocation pattern of isolated zygomatic arch fractures. Left: m-shaped impression; middle: impressed posterior arch fragment; right: medially dislocated intermediate fragment.
Fig. 2. Dislocation pattern of combined fractures of zygomatic bone and arch. Rotational dislocation of zygomatic bone around vertical axis: left: with m-shaped impression of zygomytic arch; middle: with step of zygomatic arch; right: with medial dislocation of intermediate fragment.
the operations including the ultrasonographic examinations. The isolated zygomatic arch fractures were reduced without exposition of the fracture sites using a bent hook with a sharp end. It was inserted via a stab incision placed 3 cm below the arch19. In the patients with combined fractures, the fracture sites were exposed via a lateral eyebrow, a subciliary and/or a buccal sulcus incision. The zygomatic bone was reduced with a transcutaneously inserted hook and stabilized using miniplate osteosynthesis. The zygomatic arch was reduced separately, if necessary. For the ultrasonographic examinations, a Siemens Elegra1 Ultrasound System with 2 broadband linear transducers (Siemens VFX13.5 or 7.5L40) was employed. The frequency was set between 7.5 and 12 MHz depending on the image quality to be achieved. For interventional use under sterile conditions the transducer was coated with a sterile endoscope covering. An incision foil covered the coupling plane (Fig. 3). A commercially available sterile gel (Instillagel1) was used. The zygomatic arch was visualized in 2 per-
pendicular planes with the transducer applied to the skin horizontally (Fig. 4) and vertically. Before and after the reduction manoeuvres the zygomatic arch contour was assessed by ultrasonography and
by palpation. Postoperatively, all patients received plane radiographs for reposition control. The achieved result was judged ‘complete’ if the fractured zygomatic bone and/or arch were in an anatomically
Fig. 3. Sterile coated transducer for intraoperative use.
The role of intraoperative ultrasonography in zygomatic complex fracture repair
Fig. 4. Intraoperative ultrasonography: transducer held parallel to long axis of the zygomatic arch.
correct position, and ‘adequate’ if there were minor discrepancies without clinical relevance remaining in the fragment positions. The result was judged ‘partial’ if at least 1 fragment presented with a markedly false position. Results
The results are summarized in Tables 1 and 2. The isolated zygomatic arch fractures showed a typical m-shaped displacement of 2 fragments in 8 patients, and the impression of a singular posterior or intermediate fragment in 2 patients respectively,
(Table 1, Fig. 1). In all the patients with combined fractures there was a rotational displacement of the zygomatic bone around a vertical rotation axis (Fig. 5), along with an m-shaped impression of the zygomatic arch in 6 patients, a step of the zygomatic arch in 5 patients and an impression of an intermediate arch fragment in the remaining 2 patients (Table 2, Fig. 2). The displacement of the zygomatic arch could be visualized by ultrasonography in all 25 cases. The ultrasound images were always concordant with the radiological findings. Palpation was sufficient in only 10 patients, 7 of whom were suffering
Fig. 5. 3D reconstruction from CT scan of patient M-51.5, visualizing the typical displacement of the zygomatic bone with rotation around a vertical rotation axis.
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from isolated zygomatic arch fractures with m-shaped displacement. After repositioning, the alignment of the zygomatic arch could be correctly assessed by ultrasonography in 24 patients; in the remaining patient the arrangement of the fragments was misinterpreted on the ultrasound images. The repositioning of 7 isolated zygomatic arch fractures with mshaped dislocation could be assessed by palpation alone, whereas for the combined fractures palpation turned out to be uncertain in all but 1 patient. The intraoperative ultrasonography revealed 5 isolated zygomatic arch fractures and 7 combined fractures to be reduced incompletely. This prompted the surgeon to exert further repositioning efforts on the zygomatic bone and/or arch. The final ultrasonographic control showed the zygomatic arch to be well aligned in 24 out of 25 patients. The postoperative radiographs confirmed these results showing the zygomatic bone and/or arch with an anatomically correct or nearly correct position and projection (judged ‘complete’ or ‘adequate’) in 24 patients. Two clinical examples are presented in Figs 6 and 7. The patient in whom ultrasonographic examination had been insufficient only received an acceptable repositioning result (judged ‘partial’). Discussion
Displaced fractures of the zygomatic complex with disruption of the zygomatic arch contour require intraoperative control of the zygomatic arch. In isolated zygomatic arch fractures the surgeon must be assured of sufficient repositioning, because only the complete repositioning of the zygomatic arch has proved to be stable due to fragment interlocking22. In patients with zygomatic bone fractures the correct alignment of the zygomatic arch ensures sufficient sagittal projection of the zygomatic complex and prevents broadening of the facial width. A compressed zygomatic arch or an intermediate arch fragment not fitting into the gap indicates that the lateral part of the zygomatic body is displaced posteriorly. The zygomatic arch is thus considered the key in complex midfacial fracture repair11. The exposed fracture sites at the lateral and inferior orbital rim3 do not reflect the position of the zygomatic bone adequately, as correct alignment in these regions may be accompanied by an unrecognized distinct impression of the lateral part of the bone4,21. The sphenozygomatic suture is a valuable region for repositioning assessment, but also fails to indicate a false position at its
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Fig. 6. Patient F-37.7 with isolated zygomatic arch fracture: (a) CT scan and (b) ultrasound image. Result of repositioning: (c) ultrasound image and (d) radiograph.
lateral end. Assessment of the zygomaticomaxillary buttress is often uncertain, too, due to a comminuted fracture at this site21, and it requires an additional surgical approach, which would otherwise usually be considered nonessential. If an isolated zygomatic arch fracture with m-shaped dislocation is treated, repositioning is frequently associated with a definite fragment movement and a tangible clicking indicating interlocking of the fragments22. In these cases transcutaneous palpation is satisfactory as an intraoperative reduction control. In 9 of our patients with m-shaped arch displacement (7 with an isolated arch fracture, 2 with a combined fracture), sufficient zygomatic arch alignment could also be proved by palpation alone, the additional ultrasound images serving as confirmation. In isolated zygomatic arch fractures with a different kind of displacement and with only 1 impressed fragment or with a missing interfragmentary contact, the repositioning movement is not so clearly detectable.
In patients with combined fractures, it is the more complex fracture pattern with several fragments being in a false position and the soft-tissue swelling persisting at the operation date that complicate the clinical evaluation. For these reasons, assessment of the repositioning by palpation was not sufficient in 4 patients with isolated zygomatic arch fractures and in 9 with combined fractures in the present study. An additional technique for intraoperative examination is evidently necessary. The radiological visualization of the zygomatic arch using a c-bow is difficult to achieve9, and exposes the patient and staff to irradiation. The intraoperative CT scan is not widely available, as it requires a mobile CT scanner operated by a radiologist13. The endoscope inserted through temporal, preauricular or intraoral incisions enables repositioning with a direct view of the zygomatic arch2,16; as the fracture sites are exposed osteosynthesis of the zygomatic arch is possible, too.
Endoscopic visualization of the zygomatic arch is however a technically demanding and time-consuming process; palsy of facial nerve branches, temporal hollowing and necrosis of the zygomatic arch may occur, and osteosynthesis is only rarely required4,22. The coronal approach to the zygomatic arch is highly invasive with considerable shortcomings2,11,16, and is thus restricted to complex trauma with the need for multiple osteosyntheses4,11,21. Ultrasonography is easy and quick to perform; it is noninvasive and free of any risks. The possibility of ultrasonographic fracture visualization in the midface has already been described elsewhere6,7,15,17,18. Through the development of modern ultrasound systems former disadvantages of the technique have been overcome. Transducers working with high frequencies up to 12 MHz shorten the focus to superficial regions, so that the use of a water-filled conductor, as recommended by AKIZUKI et al.1, is no longer
The role of intraoperative ultrasonography in zygomatic complex fracture repair
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Fig. 7. Patient M-51.5 with combined fracture of zygomatic bone and arch: (a) CT scan and (b) ultrasound image. Result of repositioning: (c) ultrasound image and (d) radiograph. The small persistent displacement of the intermediate zygomatic arch fragment is clearly visible in both the ultrasound image and the radiograph.
necessary. Modern linear transducers receive additional ultrasound signals from the peripheral sectors of the examined region which can be used for image formation; the visualized area is thus enlarged and the physician is able to see almost the whole zygomatic arch on 1 screenshot, which simplifies the assessment of its contour9. Analysis of harmonic ultrasound frequencies (Tissue Harmonic Imaging1)20 improves image quality so that even slim bones such as the zygomatic arch are visualized with high contrast. The enhanced lateral solution enables the detection of the smallest dislocations. Using ultrasonography in a comparative study, MCCANN et al.18 were able to detect zygomatic arch fractures which remained obscure in the radiographs of 4 out of 22 patients. The application of a sterile coating makes the intraoperative use of the transducer easy. Expensive gas sterilization of the transducer1 or cover-
ing of the entire surgical area with a sterile foil9 may be abandoned. Adjustment of the system before surgery starts reduces the time required intraoperatively for the sonographic examination and avoids the need for intraoperative access to the keyboard. Finally, innovative algorithms enable the sonographic examination under daylight conditions5 making the darkening of the operation theatre unnecessary. In the present study all 25 zygomatic arch fractures were clearly detected by ultrasonography. The sensitivity and positive predictive value of fracture diagnosis were both 100%. These results confirm this method to be a useful visualizing tool for fractures of the zygomatic arch regardless of the type of displacement10. MCCANN et al.18 stated that a gross swelling and emphysema make the ultrasonographic visualization of bony surfaces difficult or even impossible. The problem
of an extensive swelling was overcome in the present study by choosing an ultrasound frequency of 7.5 MHz or less and by using the harmonic imaging function. Due to the enhancement of contrast and of lateral solution, the image quality was sufficient, although the ultrasound waves had to penetrate a thick layer of soft tissue. Emphysema was not really a problem in the zygomatic arch region, as it occurred predominantly in direct contact with the fractured sinus walls. After the repositioning manoeuvres, assessment of the reduced zygomatic arch with ultrasonography was sufficient in all but 1 case. In the combined fractures, visualization of the zygomatic arch not only proved its correct alignment but also confirmed the proper antero-posterior projection of the zygomatic bone. In contrast, manual palpation succeeded only in isolated zygomatic arch fractures with an m-shaped dislocation; assessment
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remained uncertain in the other fracture patterns for the above-mentioned reasons. Another factor impeding palpation was the elevation of the zygomatic arch under local anaesthesia used in 2 patients. The infiltration of about 8 ml anaesthetic into the soft tissues surrounding the zygomatic arch resulted in an additional swelling. Palpation became uncertain whereas the ultrasonographic examination still worked well giving adequate repositioning control. In a considerable number of cases ultrasonography detected the remaining displacements which palpation was not able to detect. This resulted in further repositioning efforts, either the revision of the position of the zygomatic bone or the additional repositioning of the zygomatic arch. In addition, ultrasonographic visualization facilitated the positioning of the reposition instrument beneath the fragments. Fracture repair under ultrasonographic control led to excellent results in 24 out of 25 patients. The final ultrasound images corresponded exactly to the postoperative radiographs. In the 25th patient, the surgeon failed to assess the zygomatic arch contour correctly using ultrasonography: multiple echoes superficial to the zygomatic arch confused the image interpretation. The posterior fragment had a sharp end which was positioned laterally to the anterior fragment. This remaining displacement was not so clearly visible in the ultrasound images, such that the surgeon deemed the reposition to be adequate. The benefit of intraoperative ultrasonography in optimizing the repositioning of the zygomatic complex is evident. The technique is easy to perform. The examination requires only about 10 min. The sterile coating costs no more than s5. Only in isolated zygomatic arch fractures with an m-shaped impression is ultrasonography unnecessary if the reposition and the interlocking of the fragments are clearly palpable. In all other kinds of displacement (Fig. 6), and especially in the combined fractures of zygomatic bone and arch (Fig. 7), ultrasonography seems to be the best visualizing tool for intraoperative repositioning control, enabling the surgeon to assess both the alignment of the zygomatic arch and the facial projection of the zygomatic body. Ultrasono-
graphy should become an inherent part of zygomatic complex fracture repair. 13.
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Address: Dirk Gu¨licher, Department of Oral and Maxillofacial Surgery, University Hospital Tu¨bingen, Osianderstraße 2-8, D-72076 Tu¨bingen, Germany. Tel: +49 7071 2986174; Fax: +49 7071 295449. E-mail: [email protected]