Evaluation of Foramen Tympanicum Using Cone-Beam Computed

The Journal of Craniofacial Surgery & Volume 25, Number 2, March 2014 Brief Clinical Studies

he foramen tympanicum or foramen of Huschke represents a Evaluation of Foramen Tdevelopmental defect or formation in the anteroinferior aspect of the external auditory canal (EAC), posteromedial to the temporo- Tympanicum Using Cone-Beam mandibular joint (TMJ), and is an unusual condition in human skulls.1,2 Foramen tympanicum occurs during embryological de- Computed Tomography in velopment of the viscerocranial bone and was described first by Emil Huschke.3Y5 In most children, the foramen tympanicum gra- Orthodontic Malocclusions dually becomes smaller and completely closes before the age of 5 years, but it occasionally persists. An anomaly of the tympanic Nihat Akbulut, DDS, PhD,* Sebnem Kursun, DDS, PhD,Þ ring during embryogenesis could lead to an abnormal ossification of Secil Aksoy, DDS, PhD,þ Hakan Kurt, DDS, PhD,Þ the tympanic bone and to a persistent foramen tympanicum.6 Also, Kaan Orhan, DDS, PhDÞþ genetic factors may lead to delays in ossification.7 It was stated that the tympanic bone dehiscence present at the precise point of fusion Abstract: The foramen tympanicum is a persistent anatomic for- of the 2 prominences should be considered an anatomic variant only mation of the temporal bone due to a defect in ossification normal after the age of 5 years.2,8 bone physiology in neonatal or postnatal period. This study deter- Foramen tympanicum may be associated with salivary discharge mined the occurrence and location of the foramen tympanicum in a into the EAC during joint movements, or it may be associated with a Y Y Turkish sample using cone-beam computed tomography. Scans of symptomatic TMJ herniation into the EAC.2 4,9 13 Moreover, foramen 370 sites in 185 patients were retrospectively analyzed to determine tympanicum may lead to the trespassing of infections from the infratemporal fossa to the EAC and from the EAC to the infratemporal foramen tympanicum occurrence, sizes, and locations according to 5,14 their orthodontic malocclusions. Measurements were done on axial fossa or TMJ cavity. Tumors of the mastoid process and ear may extend into the TMJ, whereas otitis or otomastoiditis may involve the and sagittal sections to identify the dimensions. Differences in TMJ and can even result in ankylosis.15,16 Moreover, the connection foramen tympanicum incidence by measurements, sex, side, maloc- into EAC during athroscopy or arthrography can result in otologic clusions, and location were statistically evaluated. Foramen tym- complications.17,18 panicum was determined in 42 (22.7%) of 185 patients. No statistical These anatomical variations can be detected in clinical practice using difference was found considering location and sex (P 9 0.05), but it radiography. Conventional radiographs have several drawbacks, in- was found more bilaterally in female patients within significance level cluding errors of projection and errors of identification. Conventional at P = 0.024. Mean sizes did not differ significantly by sex but were radiographic techniques collapse a three-dimensional structure onto a found to be greater in females. In axial diameter, the average mea- two-dimensional plane. The resulting superimposition of anatomical surement was found wider on the right side of all patients (P =0.017). structures complicates image interpretation and landmark identification, The findings showed a greater foramen tympanicum dimension among and this distortion and magnification may lead to errors of identification.19,20 The use of cone-beam computed tomography (CBCT) was class II than among class I and III subjects (P G 0.05). Knowledge about first reported by Mozzo et al21 and has been proposed in the last decade these structures is helpful for the interpretation of imaging (especially for maxillofacial imaging.22,23 A CBCT scan uses a different type of cone-beam computed tomography) and provides valuable information acquisition than that used in medical CT (MDCT). Rather than capturing especially before orthognathic surgery to avoid intraoperative recon- an image as separate slices as in MDCT, CBCT produces a cone-shaped struction and complications. x-ray beam that allows an image to be captured in a single shot. The resultant volume can be reformatted to provide multiple reconstructed images (eg, sagittal, coronal, and axial) that are similar to traditional Key Words: Foramen tympanicum, foramen of Huschke, MDCT images.20,21 Cone-beam CT thus offers the distinct advantage of cone-beam computed tomography, orthodontic malocclusions a lower radiation dose than MDCT and the possibility of importing and exporting individualized, overlap-free reconstructions.24,25 Moreover, these possibilities and increasing access to CBCT imaging for surgeons and orthodontics are enabling the movement from two-dimensional cephalometric analysis to three-dimensional analysis before orthodontic analysis. Studies of CBCT applications in orthognathic surgery have From the *Oral and Maxillofacial Surgery Department, Faculty of Dentistry, examined both CBCT-generated two-dimensional cephalometric pro- Gaziosmanpaza University, Tokat; †Department of Dentomaxillofacial jections from CBCT data sets and three-dimensional cephalometric Radiology, Faculty of Dentistry, Ankara University, Besevler, Ankara; analysis, which in dicated a reliable and accurate tool for linear and and ‡Department of Dentomaxillofacial Radiology, Faculty of Dentistry, 19,21,23 Near East University, Mersin, Turkey. three-dimensional measurements before surgery. Several studies of detection of this anatomical variation, using Received July 17, 2013. 1,2,10,26 Accepted for publication August 27, 2013. conventional CT and cadaver studies, have been published. 1 Address correspondence and reprint requests to Sebnem Kursun, PhD, However, only 1 study has been conducted on CBCT imaging, but Dentomaxillofacial Radiology Department, Faculty of Dentistry, Ankara to our knowledge, no attempt has been made to study the visualization University, 06500 Ankara, Turkey; E-mail: [email protected] of foramen tympanicum according to orthodontic malocclusions using Ethical approval was obtained from the Human Research Ethics Committee. CBCT imaging. Hence, it was considered worthwhile to assess the Clearance certificate: 13-KAEK-132. occurrence and location of the foramen tympanicum according to No funding was received for this study. orthodontic malocclusions and sex in a Turkish sample using CBCT. This report will be presented at the 21st International Conference on Oral and Maxillofacial Surgery, Barcelona, Spain (October 21Y24, 2013), as oral presentation. The authors report no conflicts of interest. MATERIALS AND METHODS Copyright * 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 Data from CBCT examinations of 370 sites in 185 patients who DOI: 10.1097/SCS.0000000000000440 had been referred to our outpatient clinic during a 5-year period

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Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited. Brief Clinical Studies The Journal of Craniofacial Surgery & Volume 25, Number 2, March 2014 were analyzed retrospectively. The overall mean age was 28.6 years (range, 7Y84 [SD, 15.5] years). Informed consent was obtained from all patients before CBCT examinations. The mean age of the male patients was 29.04 (SD, 15.66) years (n = 185) (range, 7Y73 years), whereas the mean age of the female patients was 28.21 (SD, 15.43) years (n = 100) (range, 9Y84 years). Patients with evidence of bone disease (especially osteoporosis), FIGURE 2. Image showing the measurement of the size of the foramen both relevant drug consumption, skeletal asymmetries or trauma, con- in the axial and sagittal planes. genital disorders, anamnesis of surgical procedures in the TMJ, and pathological disorders of the maxilla and mandible as well as syndromic patients were excluded from the study. The study protocol Mean axial diameter was 0.5 mm, mean sagittal diameter was 1 mm, was carried out according to the principles described in the Declara- and mean coronal diameter was 1 mm. Axial images were acquired tion of Helsinki, including all amendments and revisions. Only in the orbitomeatal plane. the investigators had access to the collected data. The institutional Foramen tympanicum was identified on axial images and con- review board of the faculty reviewed and approved informed consent firmed their existence on coronal and sagittal reformatted images. forms. There was no preference for sex regarding sample choice. For every patient, we noted location of the foramen tympanicum Only high-quality scans were included. Low-quality images, such as (unilateral or bilateral) and calculated its prevalence as a percentage. those containing scattering or insufficient accuracy of bony borders, The size of the foramen was measured both in the axial and sagittal were excluded. planes and noted its size (Fig. 2). The prevalence of the persistent Patients were grouped by occlusion type according to mainly ANB foramen tympanicum according to sex and orthodontic malocclusions and the sagittal interjaw base relationship. All patients’ orthodontic was also calculated. analyses were made using CBCT-generated cephalograms. Statistical analyses were performed using SPSS software (ver- According to ANB angle, the 3 groups were defined as follows: sion 12.0.1; SPSS, Inc, Chicago, IL). Wilcoxon matched-pairs as skeletal class I (62 patients, 124 sides), class II (65 patients, 130 sides), signed ranks tests were used to assess the intraobserver reliability of and class III (58 patients, 116 sides). repeated measurements and examinations. Differences in sex, side, class I group (C) (n = 62): overjet: 2 to 4 mm; ANB angle: 0Y4 occurrence, and location were evaluated using W2 and paired t test, degrees SNA = 82 T 2 degrees, SNB = 80 T 2 degrees and measurements were evaluated using 1-way analysis-of-variance class II total (n = 65): overjet: 5 mm or greater; ANB angle: 94 tests. Differences were considered significant when P G 0.05. degrees; SNA 982 degrees, SNB G78 degrees class III group (n = 58): negative overjet: ANB angle: G0 degrees; SNA G80 degrees, SNB 984 degrees RESULTS Imaging Using CBCT Repeated measurements of CBCTs showed no significant intra- Cone-beam CT scans (NewTom 3G; Quantitative Radiology s.r.l., observer difference (P 9 0.05). Intraobserver consistency was 96.2% Verona, Italy) used 9- or 12-inch field of view to include the cra- between 2 examinations and 100% for the detection of foramen niofacial anatomy. Radiographic parameters (kV, mA) were deter- tympanicum. Of all patients, foramen tympanicum was detected mined automatically from scout views by the NewTom 3G. in 42 patients (22.7%). This was unilateral in 25 patients (59.5%) Depending on the size of the patient and the extent of beam atten- and bilateral in 17 patients (40.5%)(Figs. 3 and 4). In total, 59 cases of uation, exposure varied up to 40%. All constructions and measure- foramen tympanicum (17.35% of sides [19 sides in 16 male patients, ments were performed on a 21.3-inch flat-panel color-active matrix 40 sides in 26 female patients]) were observed (Tables 1 and 2). No TFT medical display (Nio Color 3MP; Barco, Kortrijk, Belgium) statistical difference was found considering sex (P 9 0.05), but it with a resolution of 2048 Â 1536 at 76 Hz and 0.2115-mm dot was found more bilaterally in female patients within significance pitch operated at 10 bits. level at P = 0.024. Foramen tympanicum was found in 33 (17.8%) of 185 on the right Image Evaluation side and in 26 (14.05%) of 185 on the left side (Table 2). The right side was statistically significantly different compared with the left All CBCT images were retrospectively evaluated by a dento- side, P G 0.05 (Table 2). maxillofacial radiologist with 6 years of experience (S.K.). Axial, sagittal, and coronal images were reconstructed for all images, and three-dimensional reconstructions were used as necessary (Fig. 1)

FIGURE 1. A, Axial, coronal, and sagittal CBCT images. B, Three-dimensional FIGURE 3. Axial and sagittal CBCT images with (A) and without CBCT reconstructed image. (B) foramen tympanicum. e106 * 2014 Mutaz B. Habal, MD

TABLE 2. Mean Size (SD) of Foramen Tympanicum According to Sex and Planes

Male Female Total n (Foramen Side Tympanicum) Mean (SD) Mean (SD) Mean (SD)

Right axial 33 2.68 (0.74) 2.90 (0.96)a 2.79(0.90)b Right sagittal 33 2.32 (0.78) 2.27 (0.95) 2.28 (0.89) Left axial 26 2.47 (0.67) 2.19 (0.74)a 2.31 (0.72)b Left sagittal 26 1.90 (0.50) 1.90 (0.65) 1.90 (0.59) Superscript letters indicate statistical significance (P G 0.05). Same letters show sta- FIGURE 4. Cone-beam CT images of (A, B) axial and sagittal bilateral and tistical significance. (B) unilateral foramen tympanicum.

maxillofacial structures.24,25,27Y29 High-resolution spiral CT was pre- The shape of the foramina was considered oval because their di- dominantly preferred by the researchers in estimating the frequency of foramen tympanicum. mensions in 2 planes were slightly different. Table 2 shows the 7 30 mean sizes of foramen tympanicum both in axial and sagittal planes. Mao and Nah and Jaju et al reported that an anomaly of the On the right side, their mean size was 2.79 (SD, 0.90) mm in the axial tympanic ring during embryogenesis could lead to an abnormal ossi- plane and 2.28 (SD, 0.89) mm in the sagittal plane. On the left side, fication of the tympanic bone and to a persistent foramen tympanicum their mean size was 2.31 (SD, 0.72) mm in the axial plane and 1.90 after age 5 years of patients. These findings support the genetic de- (SD, 0.59) mm in the sagittal plane (Table 2). Mean sizes did not velopment aspect of foramen tympanicum. differ significantly by sex but were found to be greater in females We determined the size of foramen tympanicum is larger at the G (P 9 0.05). However, in axial diameter, the average measurement right sides with statistically significant level (P 0.05). The size of was found wider on the right side of all patients (P = 0.017). foramen tympanicum is also larger in class II malocclusion patients We also compared the difference between orthodontic maloc- than in class I and class III malocclusion patients with statistically significant level (P G 0.05). To our knowledge and literature review, clusion and occurrence of foramen tympanicum. Of all patients, 1 14 cases (33.3%) of foramen tympanicum was found in class these findings are meaningful and interesting. Hence, we thought I patients, whereas there were 16 (38.09%) and 12 (28.5%) in class II that the condyle position and retrodiscal tissue of TMJ may cause and class III patients, respectively. No statistically significant dif- these findings; it just, if the condyle places more posteriorly in glenoid ference was found considering among location, sex, and orthodontic fossa, causes pressure to the retrodiscal tissue by its movement malocclusion (P 9 0.05) (Table 3). Table 4 shows the distribution of during the masticatory function, because the closed relation of foramen tympanicum sizes according to malocclusions. retrodiscal tissue with EAC might cause enlargement of the foramen tympanicum as seen in class II malocclusion in the current study. In class I, the mean size was 2.35 (SD, 0.87) mm in the axial 31 plane and 1.94 (SD, 0.62) mm in the sagittal plane. In class II In compliance with Cohlmia et al, present findings revealed that patients, the mean size was 2.83 (SD, 0.92) mm in the axial plane the condyles of patients in the class III group were positioned signif- and 1.99 (SD, 0.67) mm in the sagittal plane, whereas the mean size icantly more anteriorly than condyles in class II and class I patients G 31 was 2.38 (SD, 0.88) mm in the axial plane and 1.98 (SD, 0.61) mm in (P 0.05). Cohlmia et al also reported that the left condyle was more the sagittal plane for class III patients (Table 4). Statistical analysis anteriorly positioned than the right in a sample of the patients with malocclusion after comparing the anterior articular space for right and showed a greater axial foramen tympanicum dimension among 32 31 class II than classes I and III subjects (P G 0.05) (Table 4). left TMJ. Prabhat et al found similar findings with Cohlmia et al. With respect to these authors, this asymmetry could be related to nature features of maxillofacial asymmetry. Several investigators had also stated that patients with class II division II malocclusion with deep bite DISCUSSION have condyle placed more posteriorly in glenoid fossa.32Y35 These literature knowledge strengthens our findings and theory that the fo- Dental CBCT has been recommended as a dose-sparing technique, ramen tympanicum size is larger on the right side and class II mal- compared with standard MDCT scans, for the imaging of anatomical occlusion patients because of the condyle position that causes pressure landmarks before surgical procedures. The effective dose (ICRP to the retrodiscal tissue and also foramen tympanicum. Many factors 2007) from a standard dental protocol scan using a traditional CT influence the ossification process of the tympanic bone during post- was 1.5 to 12.3 times greater than comparable medium field-of-view natal life. Mechanical environment of the mandible against the tym- 27 dental CBCT scans. Cone-beam CT image quality has also been panic bone is one factor to consider.2 All knowledge mentioned above found to be equivalent to that of traditional CT for visualizing the is about the environmental or acquired aspect of the event that causes

TABLE 1. Location of the Foramen Tympanicum as Unilateral or Bilateral and Its TABLE 3. Distribution of the Foramen Tympanicum According Prevalence Was Calculated as a Percentage Orthodontic Malocclusions

Location Male, n (%) Female, n (%) Total, n (%) Malocclusion Male, n (%) Female, n (%) Total, n (%)

Absent 69 (81) 74 (74) 143 (77.2) Class I 5 (31.2) 9 (34.) 14 (33.3) Unilateral 13 (15) 12 (12) 25 (13.5) Class II 6 (37.6) 10 (38.) 16 (38.09) Bilateral 3 (3.5) 14 (14) 17 (9.18) Class III 5 (31.2) 7 (26.9) 12 (28.5) Total 85 (100) 100 (100) 185 (100) Total 16 (100) 26 (100) 42 (100)

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7. Mao JJ, Nah HD. Growth and development: hereditary and mechanical TABLE 4. Mean Size (SD) of Foramen Tympanicum According to Orthodontic modulations. Am J Orthod Dentofacial Orthop 2004;125:676Y689 Malocclusions 8. Wang RG, Bingham B, Hawke M, et al. Persistence of the foramen of Huschke in the adult: an osteological study. J Otolaryngol Axial Sizes 1991;20:251Y253 Mean (SD) P 9. Akcam T, Hidir Y, Ilica AT, et al. Temporomandibular joint herniation into the external ear canal through foramen of Huschke. Auris Nasus Malocclusion Larynx 2011;38:646Y649 Class I 2.35 (0.87) 90.05 10. Nakasato T, Nakayama T, Kikuchi K, et al. Spontaneous Class II 2.83 (0.92) G0.05* temporomandibular joint herniation into the external auditory canal Class III 2.38 (0.88) 90.05 through a persistent foramen tympanicum (Huschke): radiographic features. J Comput Assist Tomogr 2013;37:111Y113 Sagittal sizes 11. Prowse SJ, Kelly G, Agada F. Temporomandibular joint herniation and Class I 1.94 (0.62) 90.05 the foramen of Huschke: an unusual external auditory canal mass. 9 Class II 1.99 (0.67) 0.05 J Laryngol Otol 2011;125:1279Y1281 9 Class III 1.98 (0.61) 0.05 12. Lee CK, Park KH. Spontaneous temporomandibular joint herniation. *Statistical significance (P G 0.05). Otolaryngol Head Neck Surg 2011;144:292Y293 13. Vitale RF, Goncalez F, Rausis MG. Spontaneous herniation of the temporomandibular joint into the external auditory canal. A case occurrence and remains persistent or enlargement of foramen tym- report and literary review. Int Cong Ser 2003;1240:139Y143 panicum. We found that the shape of the foramen tympanicum is oval 14. Thomson HG. Septic arthritis of the temporomandibular joint in accordance with the literature knowledge1,2 because their di- complicating otitis externa. J Laryngol Otol 1989;103:319Y321 mensions in 2 planes were slightly different. 15. Faerber TH, Ennis RL, Allen GA. Temporomandibular joint ankylosis Tozo?lu et al1 estimated the frequency of foramen tympanicum to be following mastoiditis: report of a case. J Oral Maxillofac Surg 1990;48:866Y870 17.9% in a Turkish subpopulation, which is lower than the cur- 1 16. Dingle AF. Fistula between the external auditory canal and the rent search. In line with Tozo?lu et al, the present findings showed temporomandibular joint: a rare complication of otitis externa. that the frequency of foramen tympanicum existence on the right J Laryngol Otol 1992;106:994Y995 side (17.8%) was statistically significantly different compared with 17. Applebaum EL, Berg LF, Kumar A. Otologic complications following the left side (14.5%). temporomandibular joint arthroscopy. Ann Otol Rhinol Laryngol 2 Lacout et al investigated 130 ears for foramen tympanicum and 1988;97:675Y679 identified 6 (4.6%) of 130 ears with a persistent foramen 18. Herzog S, Fiese R. Persistent foramen of Huschke: possible risk tympanicum with a female preponderance among the patients. No factor for otologic complications after arthroscopy of the difference was detected among sex with respect to foramen tym- temporomandibular joint. Oral Surg Oral Med Oral Pathol 1989;68: panicum presence. The estimated ratio of foramen tympanicum in 267Y270 377 skulls was found in approximately 7.2% in a cadaveric study of 19. Kumar V, Ludlow JB, Mol A, et al. Comparison of conventional and 8 cone beam CT synthesized cephalograms. Dentomaxillofac Radiol Wang et al. Y In conclusion, clinicians must be aware of the variability in TMJ 2007;36:263 269 and ear region especially foramen tympanicum when radiographically 20. Kalender A, Orhan K, Aksoy U. Evaluation of the mental foramen and accessory mental foramen in Turkish patients using cone-beam examining those areas before orthognathic surgery to avoid intra- computed tomography images reconstructed from a volumetric operative reconstruction and complications. Moreover, additional rendering program. Clin Anat 2012;25:584Y592 studies (such as morphometric and volumetric analysis can be done 21. Mozzo P, Procacc C, Tacconi A, et al. A new volumetric CT machine in different orthodontic treatment modalities) must be conducted for dental imaging based on the cone-beam technique: preliminary with larger population series to understand the exact relationship. results. Eur Radiol 1998;8:1558Y1564 Cone-beam CT examinations may be used instead of CT scans to 22. Brown AA, Scarfe WC, Scheetz JP, et al. Linear accuracy of cone evaluate these anatomical variations. When three-dimensional imag- beam CT derived 3D images. Angle Orthod 2009;79:150Y157 ing is required to visualize the anatomical structures, CBCT should 23. Oz U, Orhan K, Abe N. Comparison of linear and angular be preferred over CT. Our study also is the first study in the lit- measurements using two-dimensional conventional methods and erature evaluating foramen tympanicum with orthodontic and or- three-dimensional cone beam CT images reconstructed from a thognathic aspect. volumetric rendering program in vivo. Dentomaxillofac Radiol 2011;40:492Y500 24. Liang X, Jacobs R, Hassan B, et al. A comparative evaluation of REFERENCES cone beam computed tomography (CBCT) and multi-slice CT (MSCT). Part I: on subjective image quality. Eur J Radiol 1. Tozo?lu U, Caglayan F, Harorli A. Foramen tympanicum or foramen of 2010;75:265Y269 Huschke: anatomical cone beam CT study. Dentomaxillofac Radiol 25. Loubele M, Bogaerts R, Van Dijck E, et al. Comparison between Y 2012;41:294 297 effective radiation dose of CBCT and MSCT scanners for 2. Lacout A, Marsot-Dupuch K, Smoker WR, et al. Foramen tympanicum, dentomaxillofacial applications. Eur J Radiol 2009;71:461Y468 or foramen of Huschke: pathologic cases and anatomic CT study. 26. Moreno RC, Chilvarquer I, Hayek JE, et al. Anatomic and radiograph Y AJNR Am J Neuroradiol 2005;26:1317 1323 study of the persistence of foramen of Huschke. Braz J 3. Chilla R. Otosialorrhoea: a rare case of a spontaneous salivary fistula Otorhinolaryngol 2005;71:679 Y of the external auditory canal. HNO 2002;50:943 945 27. Ludlow JB, Ivanovic M. Comparative dosimetry of dental CBCT 4. Sharma PD, Dawkins RS. Patent foramen of Huschke and spontaneous devices and 64-slice CT for oral and maxillofacial radiology. salivary fistula. J Laryngol Otol 1984;98:83Y85 Oral Surg Oral Med Oral Pathol Oral Radiol Endod 5. Fusconi M, Benfari G, Franco M, et al. Foramen of Huschke: case 2008;106:106Y114 report and experimental procedure for diagnosis of spontaneous salivary 28. Ludlow JB, Gubler M, Cevidanes L, et al. Precision of cephalometric fistula. J Oral Maxillofac Surg 2009;67:1747Y1751 landmark identification: cone-beam computed tomography vs 6. Kenji A. Role of the tympanic ring in the pathogenesis of congenital conventional cephalometric views. Am J Orthod Dentofacial Orthop cholesteatoma. Laryngoscope 1983;93:1140Y1146 2009;136:312Y313 e108 * 2014 Mutaz B. Habal, MD

29. Periago DR, Scarfe WC, Moshiri M, et al. Linear accuracy and enetrating head injuries with foreign body retained are relatively reliability of cone beam CT derived 3-dimensional images constructed Prare and mainly reported in the transorbital penetrating injuries, using an orthodontic volumetric rendering program. Angle Orthod mostly with wooden as the foreign body, and sometimes needle or 2008;78:387Y395 Y bullet.1 4 The clinical evidence of deep injury may be subtle to lose 30. Jaju PP. Cone beam CT detection of foramen tympanicum or foramen of Huschke. Dentomaxillofac Radiol 2012;41:619 the diagnosis of intracranial foreign bodies, so the history around 31. Cohlmia JT, Ghosh J, Sinha PK, et al. Tomographic assessment of injury should be surveyed clear to check if anything can be inserted temporomandibular joints in patients with malocclusion. Angle in skull missing. Computed tomography (CT) and magnetic reso- Orthod 1996;66:27Y35 nance imaging are essential to provide possible signs of foreign 32. Prabhat KC, Kumar Verma S, Maheshwari S, et al. Computed bodies. Severe neurological complications, such as infection, pro- tomography evaluation of craniomandibular articulation in class II gressive gliosis and granuloma, epilepsy, may occur because of the division 1 malocclusion and class I normal occlusion subjects in North foreign bodies retained, which harbor bacteria and fragment. Thus, Indian population [published online ahead of print August 16, 2012]. the foreign bodies, whether own bone or wooden or metal, should ISRN Dent 2012;2012:312031. be removed at the time of injury at all possible.2 33. Perry HT. Relation of occlusion to temporomandibular joint dysfunction: the orthodontic viewpoint. J Am Dent Assoc 1969;79:137Y141 CLINICAL REPORT 34. Loiselle RJ. Relation of occlusion to temporomandibular joint dysfunction: the prosthodontic viewpoint. J Am Dent Assoc 1969;79:145Y146 A 40-year-old man presented to the neurosurgery department for 35. Stack BC, Funt LA. Temporomandibular joint dysfunction in children. recurrent seizures within the recent 4 months, which were dis- J Pedod 1977;1:240Y247 played as lip smacking, chewing, or swallowing at first, followed by spasm of the limbs expanding from the left to bilateral, foaming at the mouth, obvious left swivel of the head, and unconsciousness, lasting for approximately 3 to 5 minutes and surrounded by a short amnesiac state. The patient had then received an ambulatory electroencephalo- A Late-Onset Seizure Due to a gram monitoring over 24 hours, showing that the abnormal epileptic electrical activity originated in the right temporal lobe. And then the Retained Intracranial Foreign complex partial seizure diagnosis was made. The patient underwent a nonenhanced CT scan to reveal a slender BodyVPencil Lead: A Case pointed foreign body of high density in the right temporal lobe and edema surrounding (Fig. 1). Magnetic resonance imaging showed Report and Review right temporal intraparenchymal mass of less uniform high signal in Qian Chunhua, MD, Wu Qun, MD T1-weighted image, high signal in T2-weighted image, and surrounding T2-hyperintense edema, with some artifact to indicate for- Abstract: A 40-year-old man presented with recent recurrent sei- eign body embraced (Fig. 2). Laboratory analysis was unremarkable. zures. He was operated on to resect the right temporal mass with a The patient described a definite traumatic history as a pencil lead being intracranially penetrated in the right temporal lobe 30 years foreign body, a pencil lead. The foreign body had entered the brain ago when he was a child playing in the classroom. For lack of any parenchyma for an accident in a child without apparent head injury, clinical manifestations, he requested to be under monitor with the sustained for 30 years. He was asymptomatic for the intervening foreign body retained. 30 years. It is rare that a pencil lead totally penetrated with an inap- Surgical excision had performed from the very location approach parent transtemporal closed head injury. The case may caution neuro- of the foreign body. We found a graphite-dyed sign of penetrating surgeons to make the complete diagnosis of retained intracranial foreign pathway in the inner side of skull flap (the outside intact), and a bodies and thinking of need for early surgical exploration, to avoid complete pencil lead in the temporal lobe, which is capsule in chronic and potentially life-threatening neurological complications. hyperplasic fibro and granuloma, the mass, and some brain parenchyma around, was also dyed by the graphite. The pathologic evaluation of the surgical specimen revealed atten- Key Words: Penetrating head injury, intracranial foreign body, uated fibrous connective tissue with pigmentation surrounding foreign pencil lead, late-onset seizure, neurosurgical procedure material (Fig. 3). Then, the patient needs to take antiepilepsy drug for a period to judge the treatment effect and then adjust the strategy. Two years’ follow-up showed that the patient had not had epileptic attack any more.

From the Department of Neurosurgery, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, People’s Republic of China. Received July 17, 2013. Accepted for publication August 27, 2013. Address correspondence and reprint requests to Wu Qun, MD, Department of Neurosurgery, the Second Affiliated Hospital, Zhejiang University School of Medicine, No. 88 Jiefang Rd, Hangzhou, Zhejiang Province, 310009, People’s Republic of China; E-mail: [email protected] The authors report no conflicts of interest. Copyright * 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 FIGURE 1. Computed tomography scan revealed a slender pointed foreign DOI: 10.1097/SCS.0000000000000439 body of high density in the right temporal lobe and edema surrounding.

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