Surg Radiol Anat DOI 10.1007/s00276-015-1435-6
ORIGINAL ARTICLE
Extra middle turbinate lamellas: a suggested new classification Mohannad A. Al-Qudah
Received: 10 November 2014 / Accepted: 19 January 2015 Ó Springer-Verlag France 2015
Abstract Purpose Proper knowledge of sinonasal configurations and anatomical structural variations is essential to perform safe endoscopic sinus surgery. Although common middle turbinate variations have been well described in literature, rare variations have not. The aims of this study are to revise the nomenclature of extra middle turbinate lamellas variations and suggest an easy classification system of these lamellas. Method A retrospective charts and medical records review was performed for consecutive cases that were diagnosed with extra lamella middle turbinate based on endoscopic and stander three-dimensional reconstruction computer tomography scan at a tertiary academic center. After extensive literature review, these lamellas were classified into four types depending on the presence or absence of uncinate process and their morphological configuration. Result Twenty-two subjects (mean age 35 years; 8 men and 14 women) were identified who had thirty extra middle turbinate lamellas. Nasal obstruction and discharge were the most common presenting symptoms. Accessory middle turbinate was the most common extra lamella been observed and bifid inferior turbinate was the least common. Ten patients (45 %) had an accompanied middle turbinate anatomical variations, 9 (41 %) had nasal septum
Accepted as oral presentation abstract in the 33rd ISIAN (International Society of Infection and Allergy of the Nose) and the 15th IRS (International Rhinology Society), Dubai, UAE, 20–24 November, 2014. M. A. Al-Qudah (&) Division of ORL-HNS, Department of Special Surgery, Jordan University of Science and Technology, P.O. Box: 3030, Irbid 22110, Jordan e-mail: [email protected]
deviation, 11 (50 %) had associated maxillary or ethmoid sinusitis and 5 (23 %) had hypoplastic maxillary sinus. Conclusion Extra middle turbinate lamella is a rare type of middle turbinate anatomical variation that can be diagnosed by careful endoscopic examination and a precise computer tomography scan review. These lamellas may have a significant association with mucosa pathologies and are commonly seen with other common middle turbinate variations. Correct description and the use of common terminology can help to further evaluate the incidence of lamellas, their pathophysiological role, and to avoid any intraoperative landmark confusion. Keywords Middle turbinate Accessory Secondary Anatomical variation CT scan Endoscopy Sinus surgery
Introduction Endoscopic sinus surgery (ESS) has become the surgical standard of care for many medically resistant sinonasal disorders [11]. Although the procedure is safe and effective, it also carries possible serious complications such as blindness and injury to intracranial structures because of the close relationship between paranasal sinuses, orbit and brain. Middle turbinate (MT) is an important landmark in the identification of anatomical structures in the lateral nasal wall. Proper knowledge of MT configurations and structural variations are essential to perform safe endoscopic sinus surgery [5]. The advancements made in nasal endoscopy and the wide use of three-dimensional reconstruction computer tomography (CT) scan allow for a more detailed view of lateral nasal wall anatomical variations. Concha bullosa
123
Surg Radiol Anat
and paradoxical MT are well-known variations that are commonly encountered in routine rhinology practice. Other structural anomalies that can mimic MT are secondary middle turbinate (SMT), accessory middle turbinate (AMT), and bifid inferior turbinate (BIT). These rare variations have been described as case reports in the majority of publications with inconsistent consensus anatomical definition [1, 2, 6–8, 10]. The objectives of this study are to revise these nomenclatures and suggest an easily classification system for the extra MT lamellas variations.
Method After obtaining our institutional review boards’ permission, the charts and medical records were reviewed of consecutive cases who found to have extra MT lamellas. The diagnosis was based on nasal endoscopy and a stander three-dimensional reconstruction CT scan with both bone and soft tissue windows in a tertiary academic center. Following an extensive literature review, endoscopic findings and CT results of these lamellas were compared and analyzed with similarly prescribed cases [1–3, 6–8, 10]. Extra MT lamellas were first classified based on the presence or absence of normal uncinate process (UP). If the UP is absent, the extra lamellas will be either accessory MT or bifid inferior turbinate based on whether the lamella reaches the middle meatus. In the presence of normal UP, the extra lamella will be either secondary or a duplicated MT (Table 1). The paranasal CT scans were also assessed to identify associated common MT variations, nasal septum deviation, the presence of hypoplastic maxillary sinus (MSH), and sinus mucosal pathology.
Results Extra MT lamellas were encountered in 22 patients. The patient’s average age was 35 years with a SD of 14 years.
There were 8 men and 14 women. Table 2 summarizes demographic data, clinical and radiological findings for this series of patients. Nasal obstruction was the most common presenting symptom and was reported in 45 % of the reviewed patients. Other presenting symptoms were nasal discharge in 32 %, headache in 18 % and epiphora in 5 %. Thirty extra MT lamellas were observed (Figs. 1, 2, 3). Five patients had bilateral lamellas and one had more than one lamella’s type on both sides. Accessory MT was the most common extra lamella been observed in 57 % and bifid inferior turbinate was the least common. Ten patients (45 %) had accompanied MT anatomical variations, 9 (41 %) had nasal septum deviation, 11 (50 %) had associated maxillary or ethmoid sinusitis and 5 (23 %) had HMS.
Discussion The nasal cavity is a region where anatomical variations are frequently seen. Joe et al. [5] cataloged nasal anatomic variations in 119 consecutive patients at the time of sinonasal surgery. They found normal MT anatomy in 63 % of their patients and described seven different shapes of MT of which CB was the most common and observed in 15 %. A typical crescent-shaped appearance UP was reported in 85 % of studied patients. The nasal turbinate development involves the outgrowth of several ridges from the lateral nasal wall called ethmoturbinals. Six ridges may initially form, separated by furrows. Each ridge and furrow has an anterior ascending and posterior descending portion that may fuse or disappear during embryological development. The first ethmoturbinal forms the agger nasi and the UP; ethmoid bulla developed from the second pneumatized ridge [11]. The remaining four ridges can develop into the middle, accessory, superior and supreme turbinate. These structures are considered to be ethmoid in their origin. In contrast, inferior turbinate originates from a completely separate
Table 1 Extra middle turbinate characteristic MT variation
UP status
OMC obstruction
Description
Origin of lamella
Unilateral/ bilateral
Bifid IT Accessory MT
Absent Absent
No Yes
Medially, inferiorly bend UP outside MM Medially bend UP into MM
Root of IT Attach to IT body
Often bilateral Often unilateral
Secondary MT
Present
No
Horizontal bar project medially posterior to the basal lamella
Lateral wall of the ethmoid
Usually bilateral
Duplicate MT
Present
Yes
Sagittal plane lamella lateral to MT and anterior to BL
Lateral wall of the ethmoid
Unilateral
MT middle turbinate, UP uncinate process, OMC osteomeatal complex, IT inferior turbinate, BL basal lamella
123
Surg Radiol Anat Table 2 Demographic and clinical data Age
35, SD 14
M:F
8:14
Type of variation Unilateral accessory
11
Bilateral accessory
3
Unilateral secondary
2
Bilateral secondary
2
Unilateral duplicate middle turbinate
3
Bilateral bifid inferior turbinate and secondary
1
Accompanied anatomical variations Nasal septum deviation
9
Hypoplastic maxillary sinus Bilateral
2
Unilateral
3
Concha bullosa Bilateral Unilateral
4 3
Paradoxical MT Bilateral
2
Unilateral
2
Associated sinus mucosal thickening Unilateral maxillary
3
Bilateral maxillary
5
Unilateral ethmoid
1
Bilateral ethmoid Positive RAST
4 6
Fig. 1 Coronal CT scan shows left accessory middle turbinate (arrow) and maxillary sinus hypoplasia
structure inferior to the ethmoid ridges called maxilloturbinal; and forms bony structures attached to the lamina papyracea of the orbit and skull base. Variations from this
development among the second and third ridges may cause anomalies associated with MT [11]. 43 % of our series had concha bullosa and/or paradoxical MT and one patient had bilateral two different types of extra lamellas. SMT has a consistent description in literature and was first described by Khanobthamchai et al. [6] in 1991 as concha-like structure consisting of bone and soft tissue, originating specifically from the posterior portion of the middle meatus; beneath the basal lamella; curving medially and then extending either superiorly; as in most cases; or inferiorly from its lateral nasal wall attachment and has an incidence between 0.8 and 6.8 % [2]. SMT was reported to be bilateral and without obstructing the ostiomeatal complex in most cases [2]. None of our three patients with SMT had sinusitis; however, recognition of this extra lamella is important during endoscopic surgical approach to posterior ethmoid region to avoid lamina papyracia injury and false impression of MT basal lamella penetration. The definitions of AMT and BIT in literature are confusing, unclear and need additional description [1, 7, 8, 10]. When the UP is medially bent and anteriorly folded it looks like false MT and has been called AMT, however, AMT has been used to describe extra MT lamella with normally located and shaped UP, probably been mistaken for duplicate MT. BIT was described for the first time by Aksungur et al. [1] in 1999 as severely medially displaced UP which can be inferiorly or superiorly rotated. Their case had a unilateral BIT and bilateral SMT. Later on, Spear et al. [10] reported the first case of bilateral BIT and Selcuk et al. [8] of bilateral BIT and a unilateral SMT. Our patients are the first case of bilateral BIT and SMT. In all previous reported cases of BIT, including our case, normal UP was absent. The absence of UP and the coexistence of SMT in the majority of BIT cases support the assumption that superior portion of the BIT could be an embryological development abnormality of the UP than the inferior turbinate. According to our classification, BIT is located outside middle meatus and so is not an anatomical predisposing factor for sinusitis development, whereas AMT carries the possibility of narrowing the infundibulum and disturbing the mucociliary clearance. Duplicate MT is an additional bony plate in the sagittal plane, located in the middle meatus lateral to the MT and anterior to the basal lamella which can narrow the ostiomeatal complex. It may attach superiorly to the skull base and projected from the lateral nasal wall. Careful endoscopic examination and CT scan evaluation can easily differentiate these rare variations from one another and other possible middle meatus pathologies such as osteomas, polyps or tumors. The maxillary sinus begins to develop at 12 weeks of fetal life as a mucosal evagination of the middle meatus
123
Surg Radiol Anat Fig. 2 Sequential coronal CT sections of the same patient show bilateral bifid inferior turbinate (arrowhead) and bilateral secondary middle turbinate (arrow)
Fig. 3 Sequential coronal CT sections and endoscopic view of the left nasal cavity of the same patient show laterally projected lamella in the sagittal plane extended superiorly toward the skull base anterior to the basal lamella. Duplicated middle turbinate
and reaches its maximum volume at late adolescent age. Embryogenic developmental abnormalities or acquired reasons, such as infection or trauma, can prevent sinus pneumatization and cause of MSH [4]. Bolger et al. [3] suggested that developmental abnormalities of the uncinate process can lead to MSH. The uncinate process may play an important role for aeration of the maxillary sinus during the expiration phase by altering the direction of exhaled air into the maxillary sinuses [9]. The incidence of MSH ranges from 1.73 to 10.4 % [4]. We observed MSH in five patients (23 %), all of them they had an accessory MT.
and one against which results can be compared. Rare anatomical variations of MT may present confusing surgical landmarks before endoscopic sinus surgery. Thus, the surgeon must be aware of their presence prior to surgery, to avoid possible complications. Computed tomography and endoscopic nasal examination play an important role in identifying these lamellas and their relationship to surrounding structures. Conflict of interest
None.
References Conclusion In summary, we feel that this classification system, used together with a uniform definition for extra middle turbinate lamellas, will provide a common standard for preoperative planning for the management of these patients,
123
1. Aksungur EH, Bic¸akc¸i K, Inal Mb et al (1999) CT demonstration of accessory nasal turbinates: secondary middle turbinate and bifid inferior turbinate. Eur J Radiol 31:174–176 2. Aykut M, Gumusburun E, Muderris S, Adigu¨zel E (1994) The secondary nasal middle concha. Surg Radiol Anat 16:307–309 3. Bolger WE, Woodruff WW, Morehead J, Parsons D (1990) Maxillary sinus hypoplasia: classification and description of
Surg Radiol Anat
4. 5.
6. 7.
associated uncinate process hypoplasia. Otolaryngol Head Neck Surg 103:759–765 Erdem T, Aktas D, Erdem G, Miman MC, Ozturan O (2002) Maxillary sinus hypoplasia. Rhinology 40:150–153 Joe JK, Ho SY, Yanagisawa E (2000) Documentation of variations in sinonasal anatomy by intraoperative nasal endoscopy. Laryngoscope 110:229–235 Khanobthamchai K, Shankar L, Hawke M et al (1991) The secondary middle turbinate. J Otolaryngol 20:412–413 Lin YL, Lin YS, Su WF, Wang CH (2006) A secondary middle turbinate co-existing with an accessory middle turbinate: an unusual combination of two anatomic variations. Acta Otolaryngol 126:429–431
8. Selcuk A, Ozcan KM, Ozcan I et al (2008) Bifid inferior turbinate: a case report. J Laryngol Otol 122:647–649 9. Sirikci A, Bayazit Y, Gu¨mu¨sburun E, Bayram M, Kanlikama M (2000) A new approach to the classification of maxillary sinus hypoplasia with relevant clinical implications. Surg Radiol Anat 22:243–247 10. Spear SA, Brietzke SE, Winslow C (2003) Bilateral bifid inferior turbinates. Ann Otol Rhinol Laryngol 112:195–196 11. Stammberger H (1991) Functional endoscopic sinus surgery: the Messerklinger technique. BC Decker, Philadelphia
123
ORIGINAL ARTICLE
Extra middle turbinate lamellas: a suggested new classification Mohannad A. Al-Qudah
Received: 10 November 2014 / Accepted: 19 January 2015 Ó Springer-Verlag France 2015
Abstract Purpose Proper knowledge of sinonasal configurations and anatomical structural variations is essential to perform safe endoscopic sinus surgery. Although common middle turbinate variations have been well described in literature, rare variations have not. The aims of this study are to revise the nomenclature of extra middle turbinate lamellas variations and suggest an easy classification system of these lamellas. Method A retrospective charts and medical records review was performed for consecutive cases that were diagnosed with extra lamella middle turbinate based on endoscopic and stander three-dimensional reconstruction computer tomography scan at a tertiary academic center. After extensive literature review, these lamellas were classified into four types depending on the presence or absence of uncinate process and their morphological configuration. Result Twenty-two subjects (mean age 35 years; 8 men and 14 women) were identified who had thirty extra middle turbinate lamellas. Nasal obstruction and discharge were the most common presenting symptoms. Accessory middle turbinate was the most common extra lamella been observed and bifid inferior turbinate was the least common. Ten patients (45 %) had an accompanied middle turbinate anatomical variations, 9 (41 %) had nasal septum
Accepted as oral presentation abstract in the 33rd ISIAN (International Society of Infection and Allergy of the Nose) and the 15th IRS (International Rhinology Society), Dubai, UAE, 20–24 November, 2014. M. A. Al-Qudah (&) Division of ORL-HNS, Department of Special Surgery, Jordan University of Science and Technology, P.O. Box: 3030, Irbid 22110, Jordan e-mail: [email protected]
deviation, 11 (50 %) had associated maxillary or ethmoid sinusitis and 5 (23 %) had hypoplastic maxillary sinus. Conclusion Extra middle turbinate lamella is a rare type of middle turbinate anatomical variation that can be diagnosed by careful endoscopic examination and a precise computer tomography scan review. These lamellas may have a significant association with mucosa pathologies and are commonly seen with other common middle turbinate variations. Correct description and the use of common terminology can help to further evaluate the incidence of lamellas, their pathophysiological role, and to avoid any intraoperative landmark confusion. Keywords Middle turbinate Accessory Secondary Anatomical variation CT scan Endoscopy Sinus surgery
Introduction Endoscopic sinus surgery (ESS) has become the surgical standard of care for many medically resistant sinonasal disorders [11]. Although the procedure is safe and effective, it also carries possible serious complications such as blindness and injury to intracranial structures because of the close relationship between paranasal sinuses, orbit and brain. Middle turbinate (MT) is an important landmark in the identification of anatomical structures in the lateral nasal wall. Proper knowledge of MT configurations and structural variations are essential to perform safe endoscopic sinus surgery [5]. The advancements made in nasal endoscopy and the wide use of three-dimensional reconstruction computer tomography (CT) scan allow for a more detailed view of lateral nasal wall anatomical variations. Concha bullosa
123
Surg Radiol Anat
and paradoxical MT are well-known variations that are commonly encountered in routine rhinology practice. Other structural anomalies that can mimic MT are secondary middle turbinate (SMT), accessory middle turbinate (AMT), and bifid inferior turbinate (BIT). These rare variations have been described as case reports in the majority of publications with inconsistent consensus anatomical definition [1, 2, 6–8, 10]. The objectives of this study are to revise these nomenclatures and suggest an easily classification system for the extra MT lamellas variations.
Method After obtaining our institutional review boards’ permission, the charts and medical records were reviewed of consecutive cases who found to have extra MT lamellas. The diagnosis was based on nasal endoscopy and a stander three-dimensional reconstruction CT scan with both bone and soft tissue windows in a tertiary academic center. Following an extensive literature review, endoscopic findings and CT results of these lamellas were compared and analyzed with similarly prescribed cases [1–3, 6–8, 10]. Extra MT lamellas were first classified based on the presence or absence of normal uncinate process (UP). If the UP is absent, the extra lamellas will be either accessory MT or bifid inferior turbinate based on whether the lamella reaches the middle meatus. In the presence of normal UP, the extra lamella will be either secondary or a duplicated MT (Table 1). The paranasal CT scans were also assessed to identify associated common MT variations, nasal septum deviation, the presence of hypoplastic maxillary sinus (MSH), and sinus mucosal pathology.
Results Extra MT lamellas were encountered in 22 patients. The patient’s average age was 35 years with a SD of 14 years.
There were 8 men and 14 women. Table 2 summarizes demographic data, clinical and radiological findings for this series of patients. Nasal obstruction was the most common presenting symptom and was reported in 45 % of the reviewed patients. Other presenting symptoms were nasal discharge in 32 %, headache in 18 % and epiphora in 5 %. Thirty extra MT lamellas were observed (Figs. 1, 2, 3). Five patients had bilateral lamellas and one had more than one lamella’s type on both sides. Accessory MT was the most common extra lamella been observed in 57 % and bifid inferior turbinate was the least common. Ten patients (45 %) had accompanied MT anatomical variations, 9 (41 %) had nasal septum deviation, 11 (50 %) had associated maxillary or ethmoid sinusitis and 5 (23 %) had HMS.
Discussion The nasal cavity is a region where anatomical variations are frequently seen. Joe et al. [5] cataloged nasal anatomic variations in 119 consecutive patients at the time of sinonasal surgery. They found normal MT anatomy in 63 % of their patients and described seven different shapes of MT of which CB was the most common and observed in 15 %. A typical crescent-shaped appearance UP was reported in 85 % of studied patients. The nasal turbinate development involves the outgrowth of several ridges from the lateral nasal wall called ethmoturbinals. Six ridges may initially form, separated by furrows. Each ridge and furrow has an anterior ascending and posterior descending portion that may fuse or disappear during embryological development. The first ethmoturbinal forms the agger nasi and the UP; ethmoid bulla developed from the second pneumatized ridge [11]. The remaining four ridges can develop into the middle, accessory, superior and supreme turbinate. These structures are considered to be ethmoid in their origin. In contrast, inferior turbinate originates from a completely separate
Table 1 Extra middle turbinate characteristic MT variation
UP status
OMC obstruction
Description
Origin of lamella
Unilateral/ bilateral
Bifid IT Accessory MT
Absent Absent
No Yes
Medially, inferiorly bend UP outside MM Medially bend UP into MM
Root of IT Attach to IT body
Often bilateral Often unilateral
Secondary MT
Present
No
Horizontal bar project medially posterior to the basal lamella
Lateral wall of the ethmoid
Usually bilateral
Duplicate MT
Present
Yes
Sagittal plane lamella lateral to MT and anterior to BL
Lateral wall of the ethmoid
Unilateral
MT middle turbinate, UP uncinate process, OMC osteomeatal complex, IT inferior turbinate, BL basal lamella
123
Surg Radiol Anat Table 2 Demographic and clinical data Age
35, SD 14
M:F
8:14
Type of variation Unilateral accessory
11
Bilateral accessory
3
Unilateral secondary
2
Bilateral secondary
2
Unilateral duplicate middle turbinate
3
Bilateral bifid inferior turbinate and secondary
1
Accompanied anatomical variations Nasal septum deviation
9
Hypoplastic maxillary sinus Bilateral
2
Unilateral
3
Concha bullosa Bilateral Unilateral
4 3
Paradoxical MT Bilateral
2
Unilateral
2
Associated sinus mucosal thickening Unilateral maxillary
3
Bilateral maxillary
5
Unilateral ethmoid
1
Bilateral ethmoid Positive RAST
4 6
Fig. 1 Coronal CT scan shows left accessory middle turbinate (arrow) and maxillary sinus hypoplasia
structure inferior to the ethmoid ridges called maxilloturbinal; and forms bony structures attached to the lamina papyracea of the orbit and skull base. Variations from this
development among the second and third ridges may cause anomalies associated with MT [11]. 43 % of our series had concha bullosa and/or paradoxical MT and one patient had bilateral two different types of extra lamellas. SMT has a consistent description in literature and was first described by Khanobthamchai et al. [6] in 1991 as concha-like structure consisting of bone and soft tissue, originating specifically from the posterior portion of the middle meatus; beneath the basal lamella; curving medially and then extending either superiorly; as in most cases; or inferiorly from its lateral nasal wall attachment and has an incidence between 0.8 and 6.8 % [2]. SMT was reported to be bilateral and without obstructing the ostiomeatal complex in most cases [2]. None of our three patients with SMT had sinusitis; however, recognition of this extra lamella is important during endoscopic surgical approach to posterior ethmoid region to avoid lamina papyracia injury and false impression of MT basal lamella penetration. The definitions of AMT and BIT in literature are confusing, unclear and need additional description [1, 7, 8, 10]. When the UP is medially bent and anteriorly folded it looks like false MT and has been called AMT, however, AMT has been used to describe extra MT lamella with normally located and shaped UP, probably been mistaken for duplicate MT. BIT was described for the first time by Aksungur et al. [1] in 1999 as severely medially displaced UP which can be inferiorly or superiorly rotated. Their case had a unilateral BIT and bilateral SMT. Later on, Spear et al. [10] reported the first case of bilateral BIT and Selcuk et al. [8] of bilateral BIT and a unilateral SMT. Our patients are the first case of bilateral BIT and SMT. In all previous reported cases of BIT, including our case, normal UP was absent. The absence of UP and the coexistence of SMT in the majority of BIT cases support the assumption that superior portion of the BIT could be an embryological development abnormality of the UP than the inferior turbinate. According to our classification, BIT is located outside middle meatus and so is not an anatomical predisposing factor for sinusitis development, whereas AMT carries the possibility of narrowing the infundibulum and disturbing the mucociliary clearance. Duplicate MT is an additional bony plate in the sagittal plane, located in the middle meatus lateral to the MT and anterior to the basal lamella which can narrow the ostiomeatal complex. It may attach superiorly to the skull base and projected from the lateral nasal wall. Careful endoscopic examination and CT scan evaluation can easily differentiate these rare variations from one another and other possible middle meatus pathologies such as osteomas, polyps or tumors. The maxillary sinus begins to develop at 12 weeks of fetal life as a mucosal evagination of the middle meatus
123
Surg Radiol Anat Fig. 2 Sequential coronal CT sections of the same patient show bilateral bifid inferior turbinate (arrowhead) and bilateral secondary middle turbinate (arrow)
Fig. 3 Sequential coronal CT sections and endoscopic view of the left nasal cavity of the same patient show laterally projected lamella in the sagittal plane extended superiorly toward the skull base anterior to the basal lamella. Duplicated middle turbinate
and reaches its maximum volume at late adolescent age. Embryogenic developmental abnormalities or acquired reasons, such as infection or trauma, can prevent sinus pneumatization and cause of MSH [4]. Bolger et al. [3] suggested that developmental abnormalities of the uncinate process can lead to MSH. The uncinate process may play an important role for aeration of the maxillary sinus during the expiration phase by altering the direction of exhaled air into the maxillary sinuses [9]. The incidence of MSH ranges from 1.73 to 10.4 % [4]. We observed MSH in five patients (23 %), all of them they had an accessory MT.
and one against which results can be compared. Rare anatomical variations of MT may present confusing surgical landmarks before endoscopic sinus surgery. Thus, the surgeon must be aware of their presence prior to surgery, to avoid possible complications. Computed tomography and endoscopic nasal examination play an important role in identifying these lamellas and their relationship to surrounding structures. Conflict of interest
None.
References Conclusion In summary, we feel that this classification system, used together with a uniform definition for extra middle turbinate lamellas, will provide a common standard for preoperative planning for the management of these patients,
123
1. Aksungur EH, Bic¸akc¸i K, Inal Mb et al (1999) CT demonstration of accessory nasal turbinates: secondary middle turbinate and bifid inferior turbinate. Eur J Radiol 31:174–176 2. Aykut M, Gumusburun E, Muderris S, Adigu¨zel E (1994) The secondary nasal middle concha. Surg Radiol Anat 16:307–309 3. Bolger WE, Woodruff WW, Morehead J, Parsons D (1990) Maxillary sinus hypoplasia: classification and description of
Surg Radiol Anat
4. 5.
6. 7.
associated uncinate process hypoplasia. Otolaryngol Head Neck Surg 103:759–765 Erdem T, Aktas D, Erdem G, Miman MC, Ozturan O (2002) Maxillary sinus hypoplasia. Rhinology 40:150–153 Joe JK, Ho SY, Yanagisawa E (2000) Documentation of variations in sinonasal anatomy by intraoperative nasal endoscopy. Laryngoscope 110:229–235 Khanobthamchai K, Shankar L, Hawke M et al (1991) The secondary middle turbinate. J Otolaryngol 20:412–413 Lin YL, Lin YS, Su WF, Wang CH (2006) A secondary middle turbinate co-existing with an accessory middle turbinate: an unusual combination of two anatomic variations. Acta Otolaryngol 126:429–431
8. Selcuk A, Ozcan KM, Ozcan I et al (2008) Bifid inferior turbinate: a case report. J Laryngol Otol 122:647–649 9. Sirikci A, Bayazit Y, Gu¨mu¨sburun E, Bayram M, Kanlikama M (2000) A new approach to the classification of maxillary sinus hypoplasia with relevant clinical implications. Surg Radiol Anat 22:243–247 10. Spear SA, Brietzke SE, Winslow C (2003) Bilateral bifid inferior turbinates. Ann Otol Rhinol Laryngol 112:195–196 11. Stammberger H (1991) Functional endoscopic sinus surgery: the Messerklinger technique. BC Decker, Philadelphia
123
