대 한 방 사 선의 학 회 지 1993 ; 29 (6) : 1313"-' 1319 Journal of Korean Radiological Society. November. 1993

N ormal Development of the Paranasal Sinuses in Children: A CT Study*

Hyung-Jin Kim, M.D., Eui Dong Park, M.D., Pil Youb Choi, M.D., Hae Gyeong Chung, M.D.**, Jae Hyoung Kim, M.D., Sung Hoon Chung, M.D.

D epartm e η t 01 Diα， 'gno s itc Radiology, College 01 Medicine, Gy e ongsαη~g Natioη a l University

- Abstract-

To evaluate the normal development of the paranasal sinuses in children with CT, authors prospectively studied with brain CT scans of 260 children without known sinus diseases, ranging in age from 7 days to 16 2 years. M값imal anteroposterior and transverse diameters(mm) and maximal cross-sectional area(mm ) of both

sides of the maxillaπ sinus were measured with the aid of computer device. As to the ethmoidal and sphenoi­ dal sinuses, we simply documented the presence of the aplastic ethmoidal sinus and calculated the age-inci­ dence of the sphenoidal sinus pneumatization, respectively.

There noted three phases in the development of the maxillaη sinus. The anteroposterior and transverse di­

ameters of the m값illay sinus increased nearly in par외 le l. The former was always greater than the latter. In no cases was the ethmoidal sinus aplastic and almost all sinuses were pneumatized even in infants 'as early as 7 days old. CT identified the conchal pattern of sphenoidal sinus pneumatization in infants as early as 11 days old. Sphenoidal sinus pueumatization was seen in 38% of the children under the age of 1 year, 82% of the children between the age of 1 and 2 years, and almost all children older than 2 years. The anteroposterior and transverse diameters of the maxillary sinus seem to reach the adult size by 8 years of age, and the conchal pattern of sphenoidal sinus pneumatization can be recognized earlier with CT than on the plain radiographs.

Index Words: Paranasal sinuses, anatomy 23.1 Paranasal sinuses. CT 23.1211

thology, but they are frequently badly INTRODUCTION influeured by patient’s motion and position. Its qu띠 ity could be degraded by the small size of Knowledge of the embryology and the de­ the sinuses and overlying soft tissue densites. velopmental anatomy of the paransal sinuses in The younger is the child, the more troublesome infants and children allows better understand­ is the case. In this regard, the cross-sectional ing of normal and abnormal sinuses. Plain radi­ imaging techniques such as computed tomogra­ ographs have played a role as an essential phy(CT) or magnetic resonance imaging(MRI) screening method in the detection of sinus pa- are superior to plain radiographs in the assess-

* 이 논문은 1991 년 도한 국 방사선연구재단의 연구비 로 이루어 졌 음. **마산 성모병원 진단방사선과 ** Deþartmeη t 01 Diα， gnos tic Radiology, Masan Suη~gmo Hospital 이 논문은 1993 년 4 월 1 일 접 수하여 199 3 년 6월 21 일 에 채택 되 었음. Received April 1, Accepted June 21. 1993

- 1313 - Journal of Korean Radiological Soci ety 1993; 29 (6) 13 13 ~ 13 19 ment of the sinus development as well as other sinus diseases. Although there are abundant reports on the embryology and development of the paranasal sinuses(l -4), few studies were done in respect to the development of the normal paranasal si­ nuses with CT. The purpose of this study is to evaluate the normal development of the para­ nasal sinuses in children with CT, especially em­ phasizing the development of the maxillaη and sphenoidal sinuses. Fig. 1. Measurement of the maxillary sinus. MATERIALS AND METHODS The maximal cross-sectional area is obtained with computer device by drawing the line conforming to the inner margin of the m값illaη sinus. A : m었imal Between August 1990 and February 1993, anteroposterior diameter of the right maxillaη slnus. T:maximal transvere diameter of the left maxillary we prospectively evaluated the brain CT scans smus of 260 children, ranging in age from 7 days to 16 years(164 boys, 96 girls). Additional axial scans parallel to the orbitomeatal line were ob­ tained with a 4-10mm collimation through the region of the paranasal sinuses. All patients un­ derwent CT examination for indications other than sinus disease, such as seizures, headache, meningitis, hydrocephalus, head trauma, brain tumors, mental retardation, or ocular problems. All the CT scans were performed with a 9800 scanner (GE Medical System, Milwaukee, WI), and all the images were photographed with a bone-window setting. We excluded the CT scans which showed the significant changes Fig. 2. Conchal pattern of pneumatization of the of chronic sinusitis, e.g., sclerosis and thicken­ sphenoidal sinus. CT scan in this 5-month-old boy ing of the bony walls of the maxillary sinuses shows bilateral well pneumatized air-containing spac­ andj or atrophy, but induded ones showing the es(arrows) between the posterior nasal cavity anteri­ orly and sphenoid bone posteriorly. mucosal reactions unaccompanied by bony or atrophic changes. Subjects with craniofacial anomaly were also exduded from the study. Pa­ documented the presence of aplastic sinus, if tients aged less than 4 years were routinely se­ any, rather than size measurement of the eth­ dated. moidal sinus owing to its complex shape. As to M

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Table 1. Meaurements of Each Side of the Maxillary Sinus According to Age

Mean Value ::1: SD NO. of Age Right maxillary sinus Left Maxillary Sinus children 2 2 AP-D*(mm) TR- D**(mm) Area(mm ) AP-D*(mm) TR-D**(mm) Area(mm ) -3mo 20 9.6 ::1: 3.4 4.3 ::1: 1.0 3.3:1:1 .9 9.8 ::1: 3.2 4.5 :t0.2 3.2 :t1.7 -6mo 16 14.2:t3.4 7.6:t2.3 8.7:t3.7 14.4:t3.2 7.4:t2.1 7.3 :t3.1 -9mo 20 15 .3:t3.7 8.8:t2.5 10.6:t5.0 14.7:t3.9 8.4:t2.5 9.5 :t3.9 -12mo 12 17.0:t3.9 9.7:t3.0 12.6:t5.7 16.7:t4.0 10.7:t2.8 12.6:t5.3 -lyr6mo 21 19.8:t3.4 11. 7:t2.8 17.0:t5.7 19.9:t3.0 11. 5 :t2.3 16.3:t5.3 -2 yr 12 23 .9:t2.6 13.7:t2.8 23 .3:t5.8 23.3:t3.2 14.0 :t3.1 23.5:t6.5 -3 15 26.1 :t2.3 16.3:t4.9 29.3 :t6.7 26.4 :t2.6 17.5 :t2.4 30.0 :t5.4 4 16 27 .9:t3.5 18.5:t3.4 33.1 :t8.3 27.7:t3.3 18.6:t3.0 33.7:t8.0 -5 15 29.6 :t3.5 21. 4 :t3.3 43.3 :t l0.0 29.7 :t3.0 20.6 :t3.0 39.5:t9.1 -6 16 29 .9 :t3.0 21. 4 :t3.6 44.1 :t9.3 29.8 :t3.1 21. 0 :t3.0 4 1.4 :t7.9 -7 16 30.5:t2.4 21. 0:t3.3 44.0 :t7.9 29.5 :t3.0 21. 8 :t3.9 42.2:t7.8 -8 14 33.8:t2.5 24.3 :t2.9 53.1 :t9.0 34.0 :t2.6 24.9 :t3.2 53.6:t 10 .5 -9 11 34.3:t2.5 23.9 :t3.2 53.0 :t 10.3 33.9:t2.9 25.0 :t3.0 53.7:t 10 .4 -10 10 33.0:t2.1 22.7:t3.1 49.6 :t9.2 33.1 :t2.2 25.1 :t4.6 50.8:t9.9 -11 14 33.0:t4.4 22.3:t4.1 50.0 :t12.7 33.7:t4.0 23:5 :t3.8 51. 7:t 10.9 -12 16 35.2:t2.3 24.9 :t3.8 57.3 :t l 1. 9 33.9 :t3.4 24.8 :t3.5 55.1:t 13 .0 >12 16 34.9:t3.7 24.9:t5.3 58.1 :t 15.4 34.5:t3.4 26.3 :t5.9 58.7:t 15.8 * anteroposterior diameter ** transverse diameter

concha1 pattern of pneumatization of the sphe­ (mm) 40 noida1 sinus if there was a discrete air-contain­ A p.D ing space between the posterior nasa1 cavity and sphenoid bone on CT(Fig. 2)(5). We did 30 not include the ana1ysis of frontal sinus devel­ opment in this study because of the great varia­ 20 tions in size and shape and the reported high rate of aplasia.

RESULT

Development of the maxillary sinus 05""yl y6m 2y ‘ 12< Maxillany sinus appeared as a discernible Fig. 3. Chronological changes of the anteroposterior (AP-D) and transverse diameters(TR-D) of the right cavity in a11 260 children. The statistica1 data maxillary sinus from the maxima1 anteroposterior diameter, maxima1 transverse diameter, and maximal cross-sectiona1 area of each side of the maxil­ larγ sinus in each age group are tabulated in Table 1.

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(mm) (m r끼， ') 40 70

AP.D 60

30 50 TR.D

40

20

30

20

o 'm ’V’y6m2)' ‘ 10 ’2‘ o 6m lyly6m 2y ‘ " ’2< Fig. 4. Chronological changest of the anteroposteri- Fig. 5. Chronological changes of the area in each or (AP-D) and transverse diameters(TR-D) of the left side of the maxillary sinus. maxillary sinus.

As shown on the line graphs which showed Table 2. Pneumatization of the Sphenoidal Sinus the chronological changes of the anteroposteri­ According to Age or and transverse diameters in each side of the NO.of No. of children with maxillaη sinus (Fig. 3 and Fig. 4), there were Age children pneumatized sphenoid sinus(%) three phases in the development of the maxil­ -3 mo 20 4(20) lary sinus: the first phase was manifested as the -6 mo 16 7(44) rather steep increment of the two dimensions -9 mo 20 9(45) by the age of six months; the second phase as -12 mo 12 6(50) the more gradual but steady increase by the age -1yr6 mo 21 16(76) of eight years; and the third phase as even -2 yr 12 11 (92) more gradual increase or the plateau-like ap­ -3 15 14(93) -4 pearance thereafter. The anteroposterior and 16 16(100) -5 transverse dimensions of both side of the 15 14(93) -6 16 15(94) maxillay sinus increased nearly in par꾀 lel as the -7 16 15(94) children grew old. The length of the fromer -8 14 13(93) was always greater than that of the latter. Both -9 11 11 (1 00) maxillany sinuses showed no significant size dif­ -10 10 9(90) ference in their areas(Fig. 5). -11 14 14(100) -12 16 16(1 00) Development of the ethmoidal sinus > 12 16 16 (1 00) All the ethmoidal sinuses examined with CT in this study showed the discernible cavities separated by multiple septa, and almost all of pneumatization was found in infants as early as them were pneumatized even in infants as early 11 days old(Fig. 6). Thirty-eight percent(26/ as 7 days old. 68) of children under 1 year of age had pneumatized sphenoidal sinus: 20%(4/20) by 3 Pneumatization of the sphenoidal sinus months, 44%(7/ 16) by 6 months, 45%(9/ 2 이 by (Table 2) 9 months, and 50%(6/ 12) by 12 months of age. The conchal pattern of sphenoidal sinus Eighty-two percent(27/33) of children between

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anteroposteriorly each year until the ninth year of life (1). Thereafter, growth is slower but con­ tinues in all directions until 15 -18 years, when the sinus reaches the adult size(1 ,6). The average dimensions of the adult maxillaη sinus­ es are 32-34mm in length, 28-33mm in height, and 23-25mm in width(2,7) , and their volurne ranges from 8.5 to 15rnl(7).

The Ethmoidal Sinus: The initial outpouchings of the ethmoidal Fig. 6. Pneumatization of the sphenoidal sinus in an cells are evident as early as the fourth fetal infant with 11 days of age. CT scan shows the con­ month(2), and arise from recesses in the lateral chal pattem of pneumatization of the primitive sphe­ noidal sinus bilaterally (arrows) which is separated walls of the middle, superior, and supreme me­ with the posterior nasal cavity by the faint septum. atuses. The ethmoidal cells are always present at birth(6). They continue to expand until late 1 year and 2 years of age showed pneumatized puberty. Each adult ethmoidal sinus consists of sinus: 76%(16/ 21) by 18 months and 92%(1 1/ 3 to 15 cells(2) and has an average size of 33, 12) by 24 months of age. In almost all children 27, and 14mm in length, height, and width, older than 2 years, the pneumatized sphenoidal respectively(5). sinus was clearly seen on CT scans. The Frontal Sinus: DISCUSSION The frontal sinus begins to develop in the region of the frontal recess during the fourth Embryology and Developmental or fifth month of fetallife(2). A definitive fron­ Anatomy of the Paranasal Sinuses tal sinus is rarely seen at birth and is frequently The development of paranasal sinuses is initiat­ not present until the second or third year of ed with the evaginations of the mucous mem­ life(4,7) . It is the most variable sinus in devel­ brane of the nasal meatuses. Embrγologic evi­ opment and is said to fail to develop in 4% of dence of the origins of the sinuses is present at the population(5). Shapiro and Schorr(8) as­ the third to fourth month of fetal life(6), but cribed the pronounced variability in frontal much of expansion into the skeletal elements sinus pneumatization to three factors, i.e., takes place postnatally. craniofacial configuration, thickness of the frontal bone, and growth horrnones. Generally The Maxillary Sinus: radiographically the frontal sinus cannot be de­ The maxillary sinus is the first sinus devel­ tected before the age of 5 to 7(6,7). It contin­ oping in the human fetus as an outpouching ues to grow until puberty, when it reaches the structure from the lateral wall of the ethmoidal adult size and shpae. infundibulum(2,5). At birth, a rudimentary sinus, approximately 7 -8mm in length The Sphenoidal Sinus: (anteroposterior diameter), 4-6mm in height The sphenoidal sinus emerges in the third (vertical diarneter), and 3-4mm in width (trans­ or fourth fetal month as invaginations of the verse diameter), is present (4). The growth rate posterosuperior part of the sphenoethmoidal is 2mm vertic떠 ly and laterally and 3mm recess. The invaginations become pouch-like

- 1317 - Journal of Korean Rad io logi ca l Society 1993; 29 (6) 1313 ~ 1319 cavities(conchal sinuses) within the sphenoidal crease the irradiation dose to the patient. The concha(ossides of Bertin) which becomes at­ coronal-reconstituted images are too crude to tached inferiorly to the sphenoidal body around be considered appropriate for the accurate three to five years of age postnatally. Following measurement. fusion of the sphenoidal concha to the sphenoi­ Aplasia of the maxillary sinus is rare. dal boey, pneumatization progresses into the Karmody et al, (12) reported three patients presphenoid and later the basisphenoid parts of with the aplastic maxillaη sinus in their roent­ the sphenoid bone, with the sphenoidal concha genographic review of 750 adu1t patients. In remaining as the anterior sinus wall(7, 9,10). our CT study of 260 children, there was no The patterns of pneumatization of the sphenoi­ case of the aplastic maxillary sinus either unilat­ dal sinus vary greatly in individuals, and are erally or bilaterally. As far as we know, aplasia cIassified into conchal, presphenoidal, basis­ of the ethmoidal sinus is virtually absent(6). In phenoidal, and occipitosphenoidal(7, 1 0,11). our study, we could constantly detect the eth­ The sinus reaches the adult size in adolescence moidal cells as the multiloculated cavities. Most 、 and its volume ranges from 1 to 6ml. of them were pneumatized CT examination provided us the valuable in­ Our results concerning pneumatization of formations about the development of the maxil­ the sphenoidal sinus are somewhat different laη sinus. Our data on the measurement of the from those of others. According to Fujioka and m강ållaη sinus are comparable to those by oth­ Young(l O) , the radiographic evidence of ers except that it seems to reach the adu1t size pneumatization of the sphenoidal sinus could somewhet earlier than previously described(l,6, not be detected in children less than six months 8). In our series, the size increment of the max­ of age. They also stated that 50% and 90% of illary sinus in the anteroposterior and trans­ children were pneumatized by 2 and 4 years of verse diameters is steadily progressive until age, respectively. In contrast, our study shows eight years of age. During the earliest part of that the most primitive type of pneumatization this period, that is, until six months of age, the of the sphenoidal sinus, i.e., the conchal pat­ growth rate is somewhat faster than during the tern, is not infrequently visible even in children rest of period. Mter eight years of age, the de­ less than 6 months of age(l1j 36, 31 %) on CT velopment of the maxillaπ sinus is much slower scans. Seventy-six percent of children between or even stable. Our results show the 12 and 18 months of age had sphenoidal sinus anteroposterior diameter of the maxillaη sinus pneumatization. Thereafter, almost all children is always greater than the transverse diameter showed pneumatization of the sphenoidal sinus. regardless of the age as stated by Schaeffer(8), On the basis of our results, we presume that and these two dimensions run in almost parallel the anteroposterior and transverse diameters of fashion the maxillaπ sinus seem to almost reach the It is the major drawback of this study that adult size by eight years of age in most of pop­ the vertical dimension(height) and volume of ulation. The conchal pattern of sphenoidal the maxillary sinus were not measured in the sinus pneumatization can be recognized earlier evaluation of the normal postnatal development with CT than on the plain radiographs. We of the maxillaη sinuses. This drawback is as­ think CT is a valuable method in the evaluation cribed to the inherent limitation of CT; for ob­ of the development of the paranasal sinuses taining the height of the maxillary sinus, the more dearly. coronal scans should be done with the patient’s head repositioned. This should inevitably in-

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gol Clin North Am 1971;4:127-142 7. Moss-Salentijn L. Anatomy and embryology. In: REFERENCES Blitzer A, Lawson W, Friedman WH, eds. Sur­ gerγ of the paranasal sinuses. Philadelphia:W.B 1. Davis WB. Anatomy of the nasal accessoπ sinus­ Saunders Company, 1985; 12-17 es in infancy and childhood. Ann Otol 1918; 28: 8. Shapiro R, SchoIT S. A consideration of the 940-967 systernic factors that influence frontal sinus 2. Schaeffer JP. The nose, paranasal sinuses, naso­ pneumatization. Invest Radiol 1980;15:191-202 lacrimal passageways and olfactory organ in man. 9. Van Alyea OE. Sphenoid sinus. Arch Otolaryn­ Philadelphia: P. Blakiston’s Son & Co. 1920 goI1941;34:225-251 3. Wasson WW. Changes in the nasal accessory si­ 10. Fujioka M, Young LW. The sphenoidal sinuses: nuses after birth. Arch Otolaryngol 1933; 17: radi이0밍 C 허 patterns of normal development and 197-211 abnormal findings in infants and children. Radi­ 4. Maresh MM. Paranasal sinuses from birth to late ology 1978; 129: 133- 136 adolescence. 1. size of the paranasal sinuses as 11. Congdon ED. The distribution and mode of ori­ observed in routine posteroanterior roengeno. gin of septa and walls of the sphenoid sinus. grams. Am J Dis Child 1940; 60:55-78 Anat Rec 1920;18:97-123 5. Som PM. The paranasal sinuses. In: Bergeron 12. Karmody CS , Carter B, Vincent ME. Develop­ RT, Osborn AG, Som PM, eds. Head and Neck mental anomalies of the maxillary sinus. Trans Imaging. St. Louis: Mosby, 1984; 1-5 Am Acad Ophthalmol OtoI1977;84:723-728 6. Bernstein L. Pediatric sinus problems. Otolaryn-

〈국문 요약〉

CT 를 이용한 소아 연렁에서의 부비동 발달에 관한 연구

경상대학 교 의과대학 진단방사선과학교실， 마산 성모병원 진단방사선과*

김형진 • 박의동 • 최필엽 • 정혜경* • 검재형 • 정성훈

CT를 이용하여 소아에 있어서 부비동의 정상적인 발달과정을 알아보기 위하여 저자들은 지난 2 년 6개월간 부비동 질환이외의 다른 목적으로 뇌 CT를 시행한 260명의 아동들(생후 7 일 - 16세 )을 대상으로 그들의 CT스캔을 전향적으 로 분석하였다. 상악동에 있어서는 상악동이 가장 크게 보이는 단면에서 컴퓨터를 이용하여 양측 상악동의 최장 길 이와 폭， 또한 단연적을 구하여 각 연령별로 평균값을 산출하였고 사골동에 있어서는 크기 의 측정은 하지 않고 존재 유무만을 판단하였으며 접형동에 대하여는 각 연령별로 기포화의 빈도를 산출하였다. 상악동의 발달은 크게 3단계로 나눌수 있었는데 생후 6개 월까지는 비교적 빠른 신장을 보였고 6개 월부터 8세가 되기까지는 그 이 전보다는 약간 성 장속도가 느렸으나 지 속적 인 성장추세를 보였으며 8세후부터는 거의 빗빗 한 성장곡선을 보였다. 상악동의 길이 와 폭 은 모든 연령군에서 길이 가 폭보다 항상 크게 유지되며 성장하는 평 행한 성장콕선을 보였다. 전례에서 사골동의 존 재를 관찰할수 있었으며 생후 7 일된 영아를 포함한 거 의 대부분에서 기포화가 관찰되었다. CT로 접형동 기포화는 생후 11 일의 영아에서 갑개형(c ondhal pattern) 의 기포화가 최초로 관찰되었고 1세 이 하의 아동중 38%와 1세이상 2세미만의 아동중 82% 에서 갑개형 의 기포화를 관찰할수 있었으며 2세 이상의 거의 대부분에서 접형동의 기 포화를 확인 할수 있었다. 이상의 결과를 토대로 저자들은 상악동의 길 이와 폭은 8세가 되면 거의 성인의 크기로 성장하며 접형동의 기포화 의 증거는 단순 촬영술에서 보이는 것보다 빠른 시기에 CT로 발견할 수 있으리라고 추론한다.

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