The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
Brief Clinical Studies
population of patients unaffected by HFM. Ideally, a craniometric analysis would be completed on a larger cohort of patients with frequent computed tomographic scans to capture the growth pattern of the cranial base over time. This remains improbable, given the risks of excess radiation associated with regular imaging.
CONCLUSIONS The cranial base axis is not deviated in the patients with HFM compared with those of the age-matched controls, and there exists little difference in endocranial morphologic measurements with increasing severity of HFM. These data are interesting, given the role of the cranial base in facial growth and the varying hypotheses regarding the mechanism of disease in HFM.
REFERENCES 1. Choi JW, Ra YS, Hong SH, et al. Use of distraction osteogenesis to change endocranial morphology in unilateral coronal craniosynostosis patients. Plast Reconstr Surg 2010;126:995–1004 2. Gougoutas AJ, Singh DJ, Low DW, et al. Hemifacial microsomia: clinical features and pictographic representations of the OMENS classification system. Plast Reconstr Surg 2007;120:112e–120e 3. Gorlin RJ, Cohen M, Hennekam RC. Syndromes of the Head and Neck. 2nd ed. Oxford, UK: Oxford University Press; 2001 4. Murray JE, Kaban LB, Mulliken JB. Analysis and treatment of hemifacial microsomia. Plast Reconstr Surg 1984;74:186–199 5. Rune B, Selvi K, Sarnas KV, et al. Growth in hemifacial microsomia studied with the aid of roentgen stereophotogrammetry and metallic implants. Cleft Palate J 1981;18:128–146 6. David DJ, Mahatumarat C, Cooter RD. Hemifacial microsomia: a multisystem classification. Plast Reconstr Surg 1987;80:525–535 7. Kaban LB, Moses MH, Mulliken JB. Surgical correction of hemifacial microsomia in the growing child. Plast Reconstr Surg 1988;82:9–19 8. Francel PC, Park TS, Marsh JL, et al. Frontal plagiocephaly secondary to synostosis of the frontosphenoidal suture: case report. J Neurosurg 1995;83:733–736 9. Marsh JL, Gado MH, Vanier MW, et al. Osseous anatomy of the unicoronal synotosis. Cleft Palate J 1986;23:87–100 10. Kane AA, Lo LJ, Vanier MW, et al. Mandibular dysmorphology in unicoronal synostosis and plagiocephaly without synostosis. Cleft Palate Craniofac J 1996;33:418–423 11. Miller RI, Clarren SK. Long-term developmental outcomes in patients with deformational plagiocephaly. Pediatrics 2000;105:E26 12. Sakurai A, Hirabayashi S, Sugawara Y, et al. Skeletal analysis of craniofacial deformities in brachycephaly: comparison with craniofacial deformities in plagiocephaly. Scand J Plast Reconstr Surg Hand Surg 2001;35:165–175 13. Besson A, Pellerin P, Doual A. Study of asymmetries of the cranial vault in plagiocephaly. J Craniofac Surg 2002;13:664–669 14. Peitsch WK, Keefer CH, Labrie RA, et al. Incidence of cranial asymmetry in healthy newborns. Pediatrics 2002;110:e72 15. St John D, Mulliken JB, Kaban LB, et al. Anthropometrics analysis of mandibular asymmetry in infants with deformational posterior plagiocephaly. J Oral Maxillofac Surg 2002;60:873–877 16. Meara JG, Burvin R, Bartlett RA, et al. Anthropometric study of synostotic frontal plagiocephaly: before and after fronto-orbital advancement with correction of nasal angulation. Plast Reconstr Surg 2003;112:731–738 17. Baumler C, Leboucq N, Captier G. Mandibular asymmetry in plagiocephaly without synostosis [in French]. Rev Stomatol Chir Maxillofac 2007;108:424–430 18. Lee RP, Teichgraeber JF, Baumgartner JE, et al. Long-term treatment of effectiveness of molding helmet therapy in the correction of posterior deformational plagiocephaly: a five-year follow up. Cleft Palate Craniofac J 2008;45:240–245 19. Plooij JM, Verhamme Y, Berge SJ, et al. Unilateral craniosynostosis of the frontosphenoidal suture: a case report and a review of the literature. J Craniomaxillofac Surg 2009;37:162–166
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20. Burck U. Genetic aspects of hemifacial microsomia. Hum Genet 1983;64:291–296 21. Kelberman D, Tyson J, Chandler DC, et al. Hemifacial microsomia: progress in understanding the genetic basis of a complex malformation syndrome. Hum Genet 2001;109:638–645 22. Johnston MC, Bronsky PT. Animal models for human craniofacial malformations. J Craniofac Genet Dev Biol 1991;11:277–291 23. Thomas IT, Frias JL. The heart in selected congenital malformations. A lesson in pathogenetic relationships. Ann Clin Lab Sci 1987;17: 207–210 24. Werler MM, Sheehan JE, Hayes C, et al. Vasoactive exposures, vascular events, and hemifacial microsomia. Birth Defects Res A Clin Mol Teratol 2004;70:389–395 25. Schinzel A. Possible vascular disruptive origin of hemifacial microsomia? Am J Obstet Gynecol 1987;157:1319 26. Throne C. Grabb and Smith’s Plastic Surgery. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007
Computed Tomography Image Guidance for More Accurate Repair of Anterior Table Frontal Sinus Fractures Justine C. Lee, MD, PhD,* Brian T. Andrews, MD,† Hamid Abdollahi, MD,‡ Alex G. Lambi, BA,‡ Clifford T. Pereira, MBBS,* James P. Bradley, MD*‡ Background: Anterior table frontal sinus fractures accompanied by nasofrontal duct injury require surgical correction. Extracranial approaches for anterior table osteotomies have traditionally used plain radiograph templates or a “cut-as-you-go” technique. We compared these methods with a newer technique utilizing computed tomography (CT)–guided imaging. Methods: Data of patients with acute, traumatic anterior table frontal sinus fractures and nasofrontal duct injury between 2009 and 2013 were reviewed (n = 29). Treatment groups compared were as follows: (1) CT image guidance, (2) plain radiograph template, and (3) cut-as-you-go. Frontal sinus obliteration was performed in all cases. Demographics, operative times, length of stay, complications, and osteotomy accuracy were recorded.
From the *Division of Plastic and Reconstructive Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA; †Division of Plastic and Reconstructive Surgery, University of Kansas School of Medicine, Kansas City, KS; and ‡Division of Plastic Surgery, Temple University/Saint Christopher’s Hospital for Children, Philadelphia, PA. Received April 19, 2014. Accepted for publication July 23, 2014. Address correspondence and reprint requests to James P. Bradley, MD, Division of Plastic and Reconstructive Surgery, University of California, Los Angeles, 200 Medical Plaza, Suite 465, Los Angeles, CA; E-mail: [email protected] All sources of funds supporting the completion of this article are under the auspices of the University of California, Los Angeles. The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001246
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
Results: Similar demographics, concomitant injuries, operative times, and length of stay among groups were noted. No patients in the CTguided group had perioperative complications including intraoperative injury of the dura, cerebrum, or orbital structures. In the plain radiograph template group, 25% of patients had inadvertent dural exposure, and 12.5% required take-back to the operating room for cranial bone graft donor site hematoma. In the cut-as-you-go group, 11% required hardware removal for exposure. There were no cases of cerebrospinal fluid leak, meningitis, or mucocele in any group (follow-up, 29.2 months). The CT image guidance group had the most accuracy of the osteotomies (95%) compared with plain radiograph template (85%) and the cut-as-you-go group (72.5%). Conclusions: A new technique using CT image guidance for traumatic frontal sinus fractures repair offers more accurate osteotomy and elevation of the anterior table without increased operative times or untoward sequelae. Key Words: Frontal sinus fracture, CT-guided navigation, anterior table frontal sinus
O
ne of the most important determinants of clinical management in frontal sinus fractures is the patency of the nasofrontal duct.1 Ductal injury is demonstrated by 3 findings on computed tomography (CT) scans: (1) obstruction from a fracture fragment seen in the duct, (2) fracture to the base of the frontal sinus, or (3) fracture of the anterior ethmoid complex.1–3 The degree of injury also correlates to the likelihood of further complications.3 When nasofrontal duct injuries are encountered, the type of fracture repair required depends on the location of the fracture. In the setting of displaced posterior table fractures, an intracranial approach to cranialize the sinus and obliterate the nasofrontal duct is the classic, definitive method for repair. When the posterior table is intact, and the fracture is confined to the anterior table with nasofrontal duct injury, an extracranial approach can be performed. In the absence of a nasofrontal duct injury, reduction of a displaced anterior frontal sinus wall fracture may be necessary to avoid a forehead contour irregularity. Traditionally, anterior table frontal sinus wall fractures are approached by identifying the borders of the frontal sinus using plain radiographs or transillumination of the sinus.4 Although these modalities for identifying the size and location of the frontal sinus have been documented, the accuracy of such techniques has been debated.5 With the advent of CT-based image guidance, the ability to accurately map anatomic structures has been greatly increased. In this work, we describe the use of CT-based image guidance as a new tool for identifying the size and location of the frontal sinus intraoperatively during the repair of anterior table frontal sinus fractures. We compared the accuracy of this CT-guided approach for anterior frontal sinus fracture repair with the more traditional approaches using either a plain radiograph template or “cut-as-yougo” anterior table removal.
Brief Clinical Studies
of the frontal sinus and safe separation of intracranial and extracranial spaces were attempted to prevent intracranial complications such as meningitis, encephalitis, and brain abscess, as well as complications such as cerebrospinal fluid leakage, mucopyoceles, frontal osteomyelitis, meningoencephalocele, and nonunion of the frontal bone. Patients were separated into 3 groups for comparison based on the approach to the frontal sinus at the time of surgery: (1) CT image–guided (n = 10), (2) plain radiograph template (n = 8), (3) “cut-as-you-go” (n = 11). A standard preoperative craniofacial protocol CT scan (1-mm cuts from apex to hyoid) was obtained for all patients (Fig. 1). First, for the CT image–guided group, the BrainLab Navigation Systems (Feldkirchen, Germany) was used intraoperatively. Data from the CT scan were loaded onto the image guidance platform prior to surgery. Registrations were performed at the time of surgical prepping according to the manufacturer’s directions. After coronal incision and subperiosteal exposure, the stereotactic wand was used to identify and mark the borders of the frontal sinus (Fig. 2). A directed osteotomy of the anterior table of the frontal sinus was performed with small burr holes and craniotomy drill. The anterior frontal bone was removed by following the marked borders (Fig. 3). The exposed frontal sinus had all mucosa manually stripped off followed by complete removal with a diamond burr. The nasofrontal duct was then plugged, and sinus was obliterated with packed cranial bone harvested from the parietal region. A small pericranial flap was also placed within the sinus defect. The anterior wall was replaced and fixed with either 1.0-mm titanium plates and screws or Resorb X resorbable plates (KLS Martin, Jacksonville, FL). The coronal incision or forehead laceration was then closed. Second, for the plain radiograph template group, radiolucent radiographic film was used to trace the visible frontal sinus from a Caldwell view radiograph placed on a light box in the operating room. The radiographic film was sterilized and positioned as a template over the frontal bone after coronal incision and subperiosteal exposure. As above, the anterior table of the frontal bone was removed, mucosa was stripped, nasofrontal duct was plugged, sinus was obliterated, and bone flap was replaced. Third, for the “cut-as-you-go” technique, loose bone fragments from the anterior table of the frontal sinus were removed. A periosteal elevator was placed through this window into the frontal sinus to identify the extent of the frontal sinus. The borders of the frontal sinus walls were marked as a guide for osteotomy removal of the anterior frontal sinus wall. Once the anterior wall was removed, the technique was similar to above. Patient demographics, mechanism of injury, hospital stay, complications (including inadvertent dural exposure), and operative time were recorded. The preoperative and postoperative CT scans (at 6 weeks) were compared with determine the accuracy of frontal sinus osteotomy for each of the 3 techniques. The total area of the frontal sinus was measured on the preoperative CT scans and compared with the total area of the osteotomized anterior table measured on the postoperative CT scans.
METHODS A review of sequential patients with anterior table frontal sinus fractures and nasofrontal duct injuries between 2009 and 2013 with complete records was performed at the University of California, Los Angeles, Temple University, and the University of Kansas (n = 29). We studied a subset of patients with both anterior wall injuries and nasofrontal duct injuries. Our indication for frontal sinus exploration and obliteration was a nasofrontal duct injury that would likely lead to obstruction of the drainage system. Eradication
FIGURE 1. Displaced anterior table frontal sinus fractures with nasofrontal duct obstruction. A 22-year-old man presented with an anterior table fracture and nasofrontal duct obstruction after a traumatic event to the forehead. Computed tomography scans demonstrate the fracture at the base of the frontal sinus.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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TABLE 1. Operative Characteristics of Patients undergoing Anterior Table Frontal Sinus Fracture Repair Characteristics CT Image Guidance (n = 10) Mean (range) age, y
FIGURE 2. Imaged-guided delineation of frontal sinus borders using CT image guidance. Three-dimensional registrations were first performed, and the boundaries of the frontal sinus were identified using a stereotactic wand.
Statistical Analysis All statistical analyses were performed using GraphPad Prism 5 (http://www.graphpad.com/prism/Prism.htm). Briefly, a 1-way analysis of variance with Bonferroni post hoc correction was used to determine statistically significant differences between group means for osteotomy accuracy and operating room time. P < 0.05 was considered statistically significant.
RESULTS Twenty-nine patients with anterior table fractures and nasofrontal duct involvement undergoing operative repair were separated into 3 groups based on technique for an extracranial approach to the anterior table: CT image–guided, plain radiograph template, or cut-asyou-go. There were no statistically significant differences between age, sex, and comorbidities among the groups (Table 1). Mechanism of injury was also similar among the groups: motor vehicle accident (63%–72%), assault (18%–25%), and fall (9%–12%). Concomitant injuries were common among all groups, with nasal fractures as the most common injury. The mean operative times were similar among all 3 groups with 81 minutes (69–100 minutes) for the image-guided group, 83.9 minutes (64–105 minutes) for the plain radiograph group, and 81.5 minutes (60–100 minutes) for the cut-as-you-go group (Fig. 4). No statistically significant differences were noted among these groups. Perioperative complications occurred in 5 of the 29 patients. No complications occurred within the image-guided cohort. In the plain radiograph template group, 3 perioperative complications occurred including inadvertent dural exposure in 2 patients and reoperation for hematoma at the bone graft donor site. In the “cut-asyou-go” group, 2 patients required hardware removal (1 for exposure through the traumatic laceration and 1 for infection). None of the groups had cerebrospinal fluid leak, meningitis, or mucocele with an average follow-up of 29.2 months (range, 18–44 months). There were no statistically significant differences between the average hospital
FIGURE 3. Osteotomy of the Anterior Table of the Frontal Sinus Osteotomy using a craniotome was then performed on the marked borders which corresponded exactly to the borders of the anterior table (left panel). The mucosa was removed from the sinus and the duct was packed with bone (middle panel). A pericranial flap was used to obliterate the frontal sinus (right panel). The anterior table bone was replaced and secured with resorbable plates and screws.
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Male, n (%) Concomitant injuries, n (%) Facial fractures Nasal Naso-orbitoethmoid Orbital floor Zygomaxillary complex Mandible Le Fort I/II Other injuries Subdural hematoma Mean (range) operative time, min Complications
Plain Radiograph Template (n = 8)
Cut-as-You-Go (n = 11)
24.7 (15–37) 7 (87.7) 6 (75.0)
27.1 (17–40) 9 (81.8) 6 (54.5)
4 2 — — — 1
3 2 2 4 1 —
3 2 1 — — —
1 81 (69–100)
1 83.9 (64–105)
— 81.5 (60–100)
0
3
2
27.2 (20–44) 8 (80.0) 6 (60.0)
stays between the 3 groups: 5.9 days (range, 3–11 days) for the image-guided group, 6.0 days (range, 3–9 days) for the plain radiograph template group, and 6.5 days (range, 4–14 days) for the cutas-you-go group. Accuracy of anterior table osteotomies was compared on preoperative and postoperative CT scans by measuring the area of the osteotomy as a percentage of the area of the anterior table. The mean accuracy of the anterior frontal sinus osteotomy in the image-guided group was 95.2% (range, 81.2%–98.9%). The plain radiograph group demonstrated accuracy at 85.2% (range, 78.7%– 91.1%). The cut-as-you-go technique was the least accurate at 72.5% (range, 58.6%–78.9%) (Fig. 5). Computed tomography image guidance provided a greater accuracy than either on plain radiographs (P < 0.001) or the cut-as-you-go technique (P < 0.0001).
DISCUSSION The indications for intraoperative CT-based image guidance have expanded from neurosurgical procedures such as intracranial tumor ablation to various craniofacial procedures. Computed tomography image guidance has facilitated operative procedures in areas that are known to be challenging because of limited exposure such as the temporomandibular joint and posterior orbit.6,7 Intraoperative use of CT image guidance allows for delineation of hidden anatomy and improved confidence in dissecting, performing osteotomies, and completing reconstruction. With these expanded indications, specialized
FIGURE 4. Comparison of Total Operative Times Mean total operating room time for the “cut-as-you-go”, radiograph template, and CT-guided groups are shown. No statistical differences were found between the groups.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
FIGURE 5. Accuracy of Pre- and Post-Operative Frontal Sinus Area Measurements Mean accuracies of the “cut-as-you-go”, radiograph template, and CT-guided groups are shown calculated from the area of the osteotomy on postoperative CT scans in comparison to the preoperative area of the anterior table. Statistically significant differences were found between the image-guided group versus the plain radiograph (P < 0.001) and “cut-as-you-go” (P < 0.0001) groups.
equipment and attachments for the BrainLab have recently become available for plastic and craniofacial surgeons. Image guidance has not been well documented previously for its use in frontal sinus fractures of the anterior table. However, the nature of the anterior, extracranial approach requires performing an osteotomy without direct visualization of the posterior surface. Thus, there is an inherent risk of entry into the intracranial space using any technique. Our study explored the use of CT image guidance for a subset of patients with frontal sinus fractures to improve the accuracy of anterior table osteotomy. Several investigators have addressed the safety of classic techniques for identifying the borders of the frontal sinus. In a report by Sindwani and Metson,5 delineation of the frontal sinus using the Caldwell plain radiograph technique resulted in complications in one third of their patients. All of these complications occurred during the initial osteotomy and included dural tears with cerebrospinal fluid leak and exposure of orbital fat. In a series of 250 osteoplastic frontal sinusotomies, Hardy and Montgomery8 reported an 18% intraoperative complication rate with 7 patients with dural damage. Weber and colleagues9 demonstrated that the plain radiograph template method for anterior table elevation caused injuries in the periorbita in 19.5% of their 82 cases, unintentional fracture of the anterior frontal sinus wall in 19.5%, and exposure or injury of dura in 8.5% due to overestimation of the borders. In 8.5% of their patients, underestimation of the borders occurred, resulting in a small bone flap. Taken together, 56.1% of the 82 bone flaps had a complication related to inaccurate osteotomies, but this did not account for cases in which multiple complications may have occurred in the same patient.9Thus, there is evidence that plain films likely have an inherent magnification caused by the x-ray beam, thereby consistently overestimating the boundaries of the frontal sinus.10 Because of the lack of reliability in the radiograph technique, the usage and safety of computed tomographic guidance have been compared in the context of sinusitis and tumor surgery.10–13 In cadaver heads, 2 comparisons of transillumination, radiograph template, and CT image guidance were performed, which demonstrated that image guidance was statistically superior to radiograph templates and transillumination.11,13 In our study, we document the safety and efficacy of CT image guidance in the identification of the frontal sinus for fracture repair. The key component of this approach is an accurate and precise identification of the borders of the frontal sinus with the stereotactic wand to prevent injury to surrounding structures. We did not encounter any intraoperative or postoperative complications with this technique. Although the cut-as-you-go group had hardware complications, inadvertent entry into the intracranial space did not occur. For the plain radiograph group, dural injury occurred in 25% of patients similar to the complication rate reported in the literature. Most importantly, the CT image–guided group showed
Brief Clinical Studies
statistically significant superiority in accuracy for anterior table osteotomy when preoperative and postoperative CT scans were compared. This suggests that the CT-guided approach may play a role in improved surgical outcomes. Although we prefer to use cranial bone to obliterate the frontal sinus followed by a pericranial flap, other methods may be used including fat grafts, muscle, and fascia. Although we followed up the 3 groups of patients for a mean 29 months (range, 18–44 months), problematic complications such as a pyomucocele may occur years later. For any comparative study on frontal sinus repair, a long-term study that follows patients for years is necessary. In summary, a new technique using CT image guidance for traumatic frontal sinus fracture repair offered more accurate osteotomy and elevation of the anterior table without increased operative times or untoward sequelae. For surgeons who infrequently encounter frontal sinus fractures, we feel the precision gained from the CT image guidance would likely increase patient safety by preventing harm to surrounding structures. At present, CT image guidance is our preferred method for the extracranial approach to repair of anterior table frontal sinus fractures.
REFERENCES 1. Rodriguez ED, Stanwix MG, Nam AJ, et al. Twenty-six-year experience treating frontal sinus fractures: a novel algorithm based on anatomical fracture pattern and failure of conventional techniques. Plast Reconstr Surg 2008;122:1850–1866 2. Harris L, Marano GD, McCorkle D. Nasofrontal duct: CT in frontal sinus trauma. Radiology 1987;165:195–198 3. Stanwix MG, Nam AJ, Manson PN, et al. Critical computed tomographic diagnostic criteria for frontal sinus fractures. J Oral Maxillofac Surg 2010;68:2714–2722 4. Sharan R, Thankappan K, Iyer S, et al. Intraoperative transillumination to determine the extent of frontal sinus in subcranial approach to anterior skull base. Skull Base 2011;21:71–74 5. Sindwani R, Metson R. Impact of image guidance on complications during osteoplastic frontal sinus surgery. Otolaryngol Head Neck Surg 2004;131:150–155 6. Yu HB, Shen GF, Zhang SL, et al. Navigation-guided gap arthroplasty in the treatment of temporomandibular joint ankylosis. Int J Oral Maxillofac Surg 2009;38:1030–1035 7. Tomazic PV, Stammberger H, Habermann W, et al. Intraoperative medialization of medial rectus muscle as a new endoscopic technique for approaching intraconal lesions. Am J Rhinol Allergy 2011;25:363–367 8. Hardy JM, Montgomery WW. Osteoplastic frontal sinusotomy: an analysis of 250 operations. Ann Otol Rhinol Laryngol 1976;85:523–532 9. Weber R, Draf W, Keerl R, et al. Osteoplastic frontal sinus surgery with fat obliteration: technique and long-term results using magnetic resonance imaging in 82 operations. Laryngoscope 2000;110:1037–1044 10. Carrau RL, Snyderman CH, Curtin HB, et al. Computer-assisted frontal sinusotomy. Otolaryngol Head Neck Surg 1994;111:727–732 11. Melroy CT, Dubin MG, Hardy SM, et al. Analysis of methods to assess frontal sinus extent in osteoplastic flap surgery: transillumination versus 6-ft Caldwell versus image guidance. Am J Rhinol 2006;20:77–83 12. Gharabaghi A, Krischek B, Feigl GC, et al. Image-guided craniotomy for frontal sinus preservation during meningioma surgery. Eur J Surg Oncol 2008;34:928–931 13. Ansari K, Seikaly H, Elford G. Assessment of the accuracy and safety of the different methods used in mapping the frontal sinus. J Otolaryngol 2003;32:254–258
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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Brief Clinical Studies
population of patients unaffected by HFM. Ideally, a craniometric analysis would be completed on a larger cohort of patients with frequent computed tomographic scans to capture the growth pattern of the cranial base over time. This remains improbable, given the risks of excess radiation associated with regular imaging.
CONCLUSIONS The cranial base axis is not deviated in the patients with HFM compared with those of the age-matched controls, and there exists little difference in endocranial morphologic measurements with increasing severity of HFM. These data are interesting, given the role of the cranial base in facial growth and the varying hypotheses regarding the mechanism of disease in HFM.
REFERENCES 1. Choi JW, Ra YS, Hong SH, et al. Use of distraction osteogenesis to change endocranial morphology in unilateral coronal craniosynostosis patients. Plast Reconstr Surg 2010;126:995–1004 2. Gougoutas AJ, Singh DJ, Low DW, et al. Hemifacial microsomia: clinical features and pictographic representations of the OMENS classification system. Plast Reconstr Surg 2007;120:112e–120e 3. Gorlin RJ, Cohen M, Hennekam RC. Syndromes of the Head and Neck. 2nd ed. Oxford, UK: Oxford University Press; 2001 4. Murray JE, Kaban LB, Mulliken JB. Analysis and treatment of hemifacial microsomia. Plast Reconstr Surg 1984;74:186–199 5. Rune B, Selvi K, Sarnas KV, et al. Growth in hemifacial microsomia studied with the aid of roentgen stereophotogrammetry and metallic implants. Cleft Palate J 1981;18:128–146 6. David DJ, Mahatumarat C, Cooter RD. Hemifacial microsomia: a multisystem classification. Plast Reconstr Surg 1987;80:525–535 7. Kaban LB, Moses MH, Mulliken JB. Surgical correction of hemifacial microsomia in the growing child. Plast Reconstr Surg 1988;82:9–19 8. Francel PC, Park TS, Marsh JL, et al. Frontal plagiocephaly secondary to synostosis of the frontosphenoidal suture: case report. J Neurosurg 1995;83:733–736 9. Marsh JL, Gado MH, Vanier MW, et al. Osseous anatomy of the unicoronal synotosis. Cleft Palate J 1986;23:87–100 10. Kane AA, Lo LJ, Vanier MW, et al. Mandibular dysmorphology in unicoronal synostosis and plagiocephaly without synostosis. Cleft Palate Craniofac J 1996;33:418–423 11. Miller RI, Clarren SK. Long-term developmental outcomes in patients with deformational plagiocephaly. Pediatrics 2000;105:E26 12. Sakurai A, Hirabayashi S, Sugawara Y, et al. Skeletal analysis of craniofacial deformities in brachycephaly: comparison with craniofacial deformities in plagiocephaly. Scand J Plast Reconstr Surg Hand Surg 2001;35:165–175 13. Besson A, Pellerin P, Doual A. Study of asymmetries of the cranial vault in plagiocephaly. J Craniofac Surg 2002;13:664–669 14. Peitsch WK, Keefer CH, Labrie RA, et al. Incidence of cranial asymmetry in healthy newborns. Pediatrics 2002;110:e72 15. St John D, Mulliken JB, Kaban LB, et al. Anthropometrics analysis of mandibular asymmetry in infants with deformational posterior plagiocephaly. J Oral Maxillofac Surg 2002;60:873–877 16. Meara JG, Burvin R, Bartlett RA, et al. Anthropometric study of synostotic frontal plagiocephaly: before and after fronto-orbital advancement with correction of nasal angulation. Plast Reconstr Surg 2003;112:731–738 17. Baumler C, Leboucq N, Captier G. Mandibular asymmetry in plagiocephaly without synostosis [in French]. Rev Stomatol Chir Maxillofac 2007;108:424–430 18. Lee RP, Teichgraeber JF, Baumgartner JE, et al. Long-term treatment of effectiveness of molding helmet therapy in the correction of posterior deformational plagiocephaly: a five-year follow up. Cleft Palate Craniofac J 2008;45:240–245 19. Plooij JM, Verhamme Y, Berge SJ, et al. Unilateral craniosynostosis of the frontosphenoidal suture: a case report and a review of the literature. J Craniomaxillofac Surg 2009;37:162–166
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20. Burck U. Genetic aspects of hemifacial microsomia. Hum Genet 1983;64:291–296 21. Kelberman D, Tyson J, Chandler DC, et al. Hemifacial microsomia: progress in understanding the genetic basis of a complex malformation syndrome. Hum Genet 2001;109:638–645 22. Johnston MC, Bronsky PT. Animal models for human craniofacial malformations. J Craniofac Genet Dev Biol 1991;11:277–291 23. Thomas IT, Frias JL. The heart in selected congenital malformations. A lesson in pathogenetic relationships. Ann Clin Lab Sci 1987;17: 207–210 24. Werler MM, Sheehan JE, Hayes C, et al. Vasoactive exposures, vascular events, and hemifacial microsomia. Birth Defects Res A Clin Mol Teratol 2004;70:389–395 25. Schinzel A. Possible vascular disruptive origin of hemifacial microsomia? Am J Obstet Gynecol 1987;157:1319 26. Throne C. Grabb and Smith’s Plastic Surgery. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007
Computed Tomography Image Guidance for More Accurate Repair of Anterior Table Frontal Sinus Fractures Justine C. Lee, MD, PhD,* Brian T. Andrews, MD,† Hamid Abdollahi, MD,‡ Alex G. Lambi, BA,‡ Clifford T. Pereira, MBBS,* James P. Bradley, MD*‡ Background: Anterior table frontal sinus fractures accompanied by nasofrontal duct injury require surgical correction. Extracranial approaches for anterior table osteotomies have traditionally used plain radiograph templates or a “cut-as-you-go” technique. We compared these methods with a newer technique utilizing computed tomography (CT)–guided imaging. Methods: Data of patients with acute, traumatic anterior table frontal sinus fractures and nasofrontal duct injury between 2009 and 2013 were reviewed (n = 29). Treatment groups compared were as follows: (1) CT image guidance, (2) plain radiograph template, and (3) cut-as-you-go. Frontal sinus obliteration was performed in all cases. Demographics, operative times, length of stay, complications, and osteotomy accuracy were recorded.
From the *Division of Plastic and Reconstructive Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA; †Division of Plastic and Reconstructive Surgery, University of Kansas School of Medicine, Kansas City, KS; and ‡Division of Plastic Surgery, Temple University/Saint Christopher’s Hospital for Children, Philadelphia, PA. Received April 19, 2014. Accepted for publication July 23, 2014. Address correspondence and reprint requests to James P. Bradley, MD, Division of Plastic and Reconstructive Surgery, University of California, Los Angeles, 200 Medical Plaza, Suite 465, Los Angeles, CA; E-mail: [email protected] All sources of funds supporting the completion of this article are under the auspices of the University of California, Los Angeles. The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001246
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
Results: Similar demographics, concomitant injuries, operative times, and length of stay among groups were noted. No patients in the CTguided group had perioperative complications including intraoperative injury of the dura, cerebrum, or orbital structures. In the plain radiograph template group, 25% of patients had inadvertent dural exposure, and 12.5% required take-back to the operating room for cranial bone graft donor site hematoma. In the cut-as-you-go group, 11% required hardware removal for exposure. There were no cases of cerebrospinal fluid leak, meningitis, or mucocele in any group (follow-up, 29.2 months). The CT image guidance group had the most accuracy of the osteotomies (95%) compared with plain radiograph template (85%) and the cut-as-you-go group (72.5%). Conclusions: A new technique using CT image guidance for traumatic frontal sinus fractures repair offers more accurate osteotomy and elevation of the anterior table without increased operative times or untoward sequelae. Key Words: Frontal sinus fracture, CT-guided navigation, anterior table frontal sinus
O
ne of the most important determinants of clinical management in frontal sinus fractures is the patency of the nasofrontal duct.1 Ductal injury is demonstrated by 3 findings on computed tomography (CT) scans: (1) obstruction from a fracture fragment seen in the duct, (2) fracture to the base of the frontal sinus, or (3) fracture of the anterior ethmoid complex.1–3 The degree of injury also correlates to the likelihood of further complications.3 When nasofrontal duct injuries are encountered, the type of fracture repair required depends on the location of the fracture. In the setting of displaced posterior table fractures, an intracranial approach to cranialize the sinus and obliterate the nasofrontal duct is the classic, definitive method for repair. When the posterior table is intact, and the fracture is confined to the anterior table with nasofrontal duct injury, an extracranial approach can be performed. In the absence of a nasofrontal duct injury, reduction of a displaced anterior frontal sinus wall fracture may be necessary to avoid a forehead contour irregularity. Traditionally, anterior table frontal sinus wall fractures are approached by identifying the borders of the frontal sinus using plain radiographs or transillumination of the sinus.4 Although these modalities for identifying the size and location of the frontal sinus have been documented, the accuracy of such techniques has been debated.5 With the advent of CT-based image guidance, the ability to accurately map anatomic structures has been greatly increased. In this work, we describe the use of CT-based image guidance as a new tool for identifying the size and location of the frontal sinus intraoperatively during the repair of anterior table frontal sinus fractures. We compared the accuracy of this CT-guided approach for anterior frontal sinus fracture repair with the more traditional approaches using either a plain radiograph template or “cut-as-yougo” anterior table removal.
Brief Clinical Studies
of the frontal sinus and safe separation of intracranial and extracranial spaces were attempted to prevent intracranial complications such as meningitis, encephalitis, and brain abscess, as well as complications such as cerebrospinal fluid leakage, mucopyoceles, frontal osteomyelitis, meningoencephalocele, and nonunion of the frontal bone. Patients were separated into 3 groups for comparison based on the approach to the frontal sinus at the time of surgery: (1) CT image–guided (n = 10), (2) plain radiograph template (n = 8), (3) “cut-as-you-go” (n = 11). A standard preoperative craniofacial protocol CT scan (1-mm cuts from apex to hyoid) was obtained for all patients (Fig. 1). First, for the CT image–guided group, the BrainLab Navigation Systems (Feldkirchen, Germany) was used intraoperatively. Data from the CT scan were loaded onto the image guidance platform prior to surgery. Registrations were performed at the time of surgical prepping according to the manufacturer’s directions. After coronal incision and subperiosteal exposure, the stereotactic wand was used to identify and mark the borders of the frontal sinus (Fig. 2). A directed osteotomy of the anterior table of the frontal sinus was performed with small burr holes and craniotomy drill. The anterior frontal bone was removed by following the marked borders (Fig. 3). The exposed frontal sinus had all mucosa manually stripped off followed by complete removal with a diamond burr. The nasofrontal duct was then plugged, and sinus was obliterated with packed cranial bone harvested from the parietal region. A small pericranial flap was also placed within the sinus defect. The anterior wall was replaced and fixed with either 1.0-mm titanium plates and screws or Resorb X resorbable plates (KLS Martin, Jacksonville, FL). The coronal incision or forehead laceration was then closed. Second, for the plain radiograph template group, radiolucent radiographic film was used to trace the visible frontal sinus from a Caldwell view radiograph placed on a light box in the operating room. The radiographic film was sterilized and positioned as a template over the frontal bone after coronal incision and subperiosteal exposure. As above, the anterior table of the frontal bone was removed, mucosa was stripped, nasofrontal duct was plugged, sinus was obliterated, and bone flap was replaced. Third, for the “cut-as-you-go” technique, loose bone fragments from the anterior table of the frontal sinus were removed. A periosteal elevator was placed through this window into the frontal sinus to identify the extent of the frontal sinus. The borders of the frontal sinus walls were marked as a guide for osteotomy removal of the anterior frontal sinus wall. Once the anterior wall was removed, the technique was similar to above. Patient demographics, mechanism of injury, hospital stay, complications (including inadvertent dural exposure), and operative time were recorded. The preoperative and postoperative CT scans (at 6 weeks) were compared with determine the accuracy of frontal sinus osteotomy for each of the 3 techniques. The total area of the frontal sinus was measured on the preoperative CT scans and compared with the total area of the osteotomized anterior table measured on the postoperative CT scans.
METHODS A review of sequential patients with anterior table frontal sinus fractures and nasofrontal duct injuries between 2009 and 2013 with complete records was performed at the University of California, Los Angeles, Temple University, and the University of Kansas (n = 29). We studied a subset of patients with both anterior wall injuries and nasofrontal duct injuries. Our indication for frontal sinus exploration and obliteration was a nasofrontal duct injury that would likely lead to obstruction of the drainage system. Eradication
FIGURE 1. Displaced anterior table frontal sinus fractures with nasofrontal duct obstruction. A 22-year-old man presented with an anterior table fracture and nasofrontal duct obstruction after a traumatic event to the forehead. Computed tomography scans demonstrate the fracture at the base of the frontal sinus.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
Brief Clinical Studies
TABLE 1. Operative Characteristics of Patients undergoing Anterior Table Frontal Sinus Fracture Repair Characteristics CT Image Guidance (n = 10) Mean (range) age, y
FIGURE 2. Imaged-guided delineation of frontal sinus borders using CT image guidance. Three-dimensional registrations were first performed, and the boundaries of the frontal sinus were identified using a stereotactic wand.
Statistical Analysis All statistical analyses were performed using GraphPad Prism 5 (http://www.graphpad.com/prism/Prism.htm). Briefly, a 1-way analysis of variance with Bonferroni post hoc correction was used to determine statistically significant differences between group means for osteotomy accuracy and operating room time. P < 0.05 was considered statistically significant.
RESULTS Twenty-nine patients with anterior table fractures and nasofrontal duct involvement undergoing operative repair were separated into 3 groups based on technique for an extracranial approach to the anterior table: CT image–guided, plain radiograph template, or cut-asyou-go. There were no statistically significant differences between age, sex, and comorbidities among the groups (Table 1). Mechanism of injury was also similar among the groups: motor vehicle accident (63%–72%), assault (18%–25%), and fall (9%–12%). Concomitant injuries were common among all groups, with nasal fractures as the most common injury. The mean operative times were similar among all 3 groups with 81 minutes (69–100 minutes) for the image-guided group, 83.9 minutes (64–105 minutes) for the plain radiograph group, and 81.5 minutes (60–100 minutes) for the cut-as-you-go group (Fig. 4). No statistically significant differences were noted among these groups. Perioperative complications occurred in 5 of the 29 patients. No complications occurred within the image-guided cohort. In the plain radiograph template group, 3 perioperative complications occurred including inadvertent dural exposure in 2 patients and reoperation for hematoma at the bone graft donor site. In the “cut-asyou-go” group, 2 patients required hardware removal (1 for exposure through the traumatic laceration and 1 for infection). None of the groups had cerebrospinal fluid leak, meningitis, or mucocele with an average follow-up of 29.2 months (range, 18–44 months). There were no statistically significant differences between the average hospital
FIGURE 3. Osteotomy of the Anterior Table of the Frontal Sinus Osteotomy using a craniotome was then performed on the marked borders which corresponded exactly to the borders of the anterior table (left panel). The mucosa was removed from the sinus and the duct was packed with bone (middle panel). A pericranial flap was used to obliterate the frontal sinus (right panel). The anterior table bone was replaced and secured with resorbable plates and screws.
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Male, n (%) Concomitant injuries, n (%) Facial fractures Nasal Naso-orbitoethmoid Orbital floor Zygomaxillary complex Mandible Le Fort I/II Other injuries Subdural hematoma Mean (range) operative time, min Complications
Plain Radiograph Template (n = 8)
Cut-as-You-Go (n = 11)
24.7 (15–37) 7 (87.7) 6 (75.0)
27.1 (17–40) 9 (81.8) 6 (54.5)
4 2 — — — 1
3 2 2 4 1 —
3 2 1 — — —
1 81 (69–100)
1 83.9 (64–105)
— 81.5 (60–100)
0
3
2
27.2 (20–44) 8 (80.0) 6 (60.0)
stays between the 3 groups: 5.9 days (range, 3–11 days) for the image-guided group, 6.0 days (range, 3–9 days) for the plain radiograph template group, and 6.5 days (range, 4–14 days) for the cutas-you-go group. Accuracy of anterior table osteotomies was compared on preoperative and postoperative CT scans by measuring the area of the osteotomy as a percentage of the area of the anterior table. The mean accuracy of the anterior frontal sinus osteotomy in the image-guided group was 95.2% (range, 81.2%–98.9%). The plain radiograph group demonstrated accuracy at 85.2% (range, 78.7%– 91.1%). The cut-as-you-go technique was the least accurate at 72.5% (range, 58.6%–78.9%) (Fig. 5). Computed tomography image guidance provided a greater accuracy than either on plain radiographs (P < 0.001) or the cut-as-you-go technique (P < 0.0001).
DISCUSSION The indications for intraoperative CT-based image guidance have expanded from neurosurgical procedures such as intracranial tumor ablation to various craniofacial procedures. Computed tomography image guidance has facilitated operative procedures in areas that are known to be challenging because of limited exposure such as the temporomandibular joint and posterior orbit.6,7 Intraoperative use of CT image guidance allows for delineation of hidden anatomy and improved confidence in dissecting, performing osteotomies, and completing reconstruction. With these expanded indications, specialized
FIGURE 4. Comparison of Total Operative Times Mean total operating room time for the “cut-as-you-go”, radiograph template, and CT-guided groups are shown. No statistical differences were found between the groups.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
FIGURE 5. Accuracy of Pre- and Post-Operative Frontal Sinus Area Measurements Mean accuracies of the “cut-as-you-go”, radiograph template, and CT-guided groups are shown calculated from the area of the osteotomy on postoperative CT scans in comparison to the preoperative area of the anterior table. Statistically significant differences were found between the image-guided group versus the plain radiograph (P < 0.001) and “cut-as-you-go” (P < 0.0001) groups.
equipment and attachments for the BrainLab have recently become available for plastic and craniofacial surgeons. Image guidance has not been well documented previously for its use in frontal sinus fractures of the anterior table. However, the nature of the anterior, extracranial approach requires performing an osteotomy without direct visualization of the posterior surface. Thus, there is an inherent risk of entry into the intracranial space using any technique. Our study explored the use of CT image guidance for a subset of patients with frontal sinus fractures to improve the accuracy of anterior table osteotomy. Several investigators have addressed the safety of classic techniques for identifying the borders of the frontal sinus. In a report by Sindwani and Metson,5 delineation of the frontal sinus using the Caldwell plain radiograph technique resulted in complications in one third of their patients. All of these complications occurred during the initial osteotomy and included dural tears with cerebrospinal fluid leak and exposure of orbital fat. In a series of 250 osteoplastic frontal sinusotomies, Hardy and Montgomery8 reported an 18% intraoperative complication rate with 7 patients with dural damage. Weber and colleagues9 demonstrated that the plain radiograph template method for anterior table elevation caused injuries in the periorbita in 19.5% of their 82 cases, unintentional fracture of the anterior frontal sinus wall in 19.5%, and exposure or injury of dura in 8.5% due to overestimation of the borders. In 8.5% of their patients, underestimation of the borders occurred, resulting in a small bone flap. Taken together, 56.1% of the 82 bone flaps had a complication related to inaccurate osteotomies, but this did not account for cases in which multiple complications may have occurred in the same patient.9Thus, there is evidence that plain films likely have an inherent magnification caused by the x-ray beam, thereby consistently overestimating the boundaries of the frontal sinus.10 Because of the lack of reliability in the radiograph technique, the usage and safety of computed tomographic guidance have been compared in the context of sinusitis and tumor surgery.10–13 In cadaver heads, 2 comparisons of transillumination, radiograph template, and CT image guidance were performed, which demonstrated that image guidance was statistically superior to radiograph templates and transillumination.11,13 In our study, we document the safety and efficacy of CT image guidance in the identification of the frontal sinus for fracture repair. The key component of this approach is an accurate and precise identification of the borders of the frontal sinus with the stereotactic wand to prevent injury to surrounding structures. We did not encounter any intraoperative or postoperative complications with this technique. Although the cut-as-you-go group had hardware complications, inadvertent entry into the intracranial space did not occur. For the plain radiograph group, dural injury occurred in 25% of patients similar to the complication rate reported in the literature. Most importantly, the CT image–guided group showed
Brief Clinical Studies
statistically significant superiority in accuracy for anterior table osteotomy when preoperative and postoperative CT scans were compared. This suggests that the CT-guided approach may play a role in improved surgical outcomes. Although we prefer to use cranial bone to obliterate the frontal sinus followed by a pericranial flap, other methods may be used including fat grafts, muscle, and fascia. Although we followed up the 3 groups of patients for a mean 29 months (range, 18–44 months), problematic complications such as a pyomucocele may occur years later. For any comparative study on frontal sinus repair, a long-term study that follows patients for years is necessary. In summary, a new technique using CT image guidance for traumatic frontal sinus fracture repair offered more accurate osteotomy and elevation of the anterior table without increased operative times or untoward sequelae. For surgeons who infrequently encounter frontal sinus fractures, we feel the precision gained from the CT image guidance would likely increase patient safety by preventing harm to surrounding structures. At present, CT image guidance is our preferred method for the extracranial approach to repair of anterior table frontal sinus fractures.
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© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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