Dekorationsartikel gehören nicht zum Leistungsumfang.
Sprache:
Englisch
235,00 €*
Versandkostenfrei per Post / DHL
Aktuell nicht verfügbar
Kategorien:
Beschreibung
The one-stop guide to microsurgical and endoscopic treatment of skull base lesions from global experts
A deep knowledge of regional anatomy, improved understanding of pathologies and their behaviors, technological advances, and multidisciplinary collaboration have led to more effective treatments for once inoperable skull base lesions. Microsurgical and Endoscopic Approaches to the Skull Base: Anatomy, Tactics, and Techniques by renowned skull base neurosurgeons Luis A. B. Borba and Jean G. de Oliveira presents a balanced, anatomy-based perspective on microsurgical and endoscopic approaches to manage these highly challenging lesions. The text leverages the best current scientific literature on this topic and insights from global skull base surgery experts.
Organized into 9 sections and 52 chapters, the book starts with discussion of microsurgical and endoscopic instrumentation and neurophysiological monitoring. The subsequent sections cover diverse approaches for skull base lesions involving the sphenoid and parasellar, orbit, anterior fossa, cavernous sinus, temporal bone and jugular foramen, and foramen magnum regions. Each of these sections starts with an introduction, followed by a microsurgical description of the anatomy of the impacted region.
Key Highlights
- Contributions from an impressive group of internationally renowned neurosurgeons and otolaryngologists specializing in skull base pathologies
- Indications, preoperative and postoperative concerns, nuances, pitfalls, tactics, techniques, and references for further reading provide a comprehensive guide to treatment
- A stepwise description of the approach, high-quality four-color drawings, and illustrative cases facilitate acquisition and retention of knowledge
- High-quality figures provide greater visual insights and step-by-step guidance on how to perform specific procedures
This unique textbook will help residents, fellows, and practitioners in neurosurgery and otolaryngology make an evidenced-based decision on using the most effective microsurgical and/or endoscopic approach to achieve the best outcomes in patients with skull base lesions.
This book includes complimentary access to a digital copy on [...]
A deep knowledge of regional anatomy, improved understanding of pathologies and their behaviors, technological advances, and multidisciplinary collaboration have led to more effective treatments for once inoperable skull base lesions. Microsurgical and Endoscopic Approaches to the Skull Base: Anatomy, Tactics, and Techniques by renowned skull base neurosurgeons Luis A. B. Borba and Jean G. de Oliveira presents a balanced, anatomy-based perspective on microsurgical and endoscopic approaches to manage these highly challenging lesions. The text leverages the best current scientific literature on this topic and insights from global skull base surgery experts.
Organized into 9 sections and 52 chapters, the book starts with discussion of microsurgical and endoscopic instrumentation and neurophysiological monitoring. The subsequent sections cover diverse approaches for skull base lesions involving the sphenoid and parasellar, orbit, anterior fossa, cavernous sinus, temporal bone and jugular foramen, and foramen magnum regions. Each of these sections starts with an introduction, followed by a microsurgical description of the anatomy of the impacted region.
Key Highlights
- Contributions from an impressive group of internationally renowned neurosurgeons and otolaryngologists specializing in skull base pathologies
- Indications, preoperative and postoperative concerns, nuances, pitfalls, tactics, techniques, and references for further reading provide a comprehensive guide to treatment
- A stepwise description of the approach, high-quality four-color drawings, and illustrative cases facilitate acquisition and retention of knowledge
- High-quality figures provide greater visual insights and step-by-step guidance on how to perform specific procedures
This unique textbook will help residents, fellows, and practitioners in neurosurgery and otolaryngology make an evidenced-based decision on using the most effective microsurgical and/or endoscopic approach to achieve the best outcomes in patients with skull base lesions.
This book includes complimentary access to a digital copy on [...]
The one-stop guide to microsurgical and endoscopic treatment of skull base lesions from global experts
A deep knowledge of regional anatomy, improved understanding of pathologies and their behaviors, technological advances, and multidisciplinary collaboration have led to more effective treatments for once inoperable skull base lesions. Microsurgical and Endoscopic Approaches to the Skull Base: Anatomy, Tactics, and Techniques by renowned skull base neurosurgeons Luis A. B. Borba and Jean G. de Oliveira presents a balanced, anatomy-based perspective on microsurgical and endoscopic approaches to manage these highly challenging lesions. The text leverages the best current scientific literature on this topic and insights from global skull base surgery experts.
Organized into 9 sections and 52 chapters, the book starts with discussion of microsurgical and endoscopic instrumentation and neurophysiological monitoring. The subsequent sections cover diverse approaches for skull base lesions involving the sphenoid and parasellar, orbit, anterior fossa, cavernous sinus, temporal bone and jugular foramen, and foramen magnum regions. Each of these sections starts with an introduction, followed by a microsurgical description of the anatomy of the impacted region.
Key Highlights
- Contributions from an impressive group of internationally renowned neurosurgeons and otolaryngologists specializing in skull base pathologies
- Indications, preoperative and postoperative concerns, nuances, pitfalls, tactics, techniques, and references for further reading provide a comprehensive guide to treatment
- A stepwise description of the approach, high-quality four-color drawings, and illustrative cases facilitate acquisition and retention of knowledge
- High-quality figures provide greater visual insights and step-by-step guidance on how to perform specific procedures
This unique textbook will help residents, fellows, and practitioners in neurosurgery and otolaryngology make an evidenced-based decision on using the most effective microsurgical and/or endoscopic approach to achieve the best outcomes in patients with skull base lesions.
This book includes complimentary access to a digital copy on [...]
A deep knowledge of regional anatomy, improved understanding of pathologies and their behaviors, technological advances, and multidisciplinary collaboration have led to more effective treatments for once inoperable skull base lesions. Microsurgical and Endoscopic Approaches to the Skull Base: Anatomy, Tactics, and Techniques by renowned skull base neurosurgeons Luis A. B. Borba and Jean G. de Oliveira presents a balanced, anatomy-based perspective on microsurgical and endoscopic approaches to manage these highly challenging lesions. The text leverages the best current scientific literature on this topic and insights from global skull base surgery experts.
Organized into 9 sections and 52 chapters, the book starts with discussion of microsurgical and endoscopic instrumentation and neurophysiological monitoring. The subsequent sections cover diverse approaches for skull base lesions involving the sphenoid and parasellar, orbit, anterior fossa, cavernous sinus, temporal bone and jugular foramen, and foramen magnum regions. Each of these sections starts with an introduction, followed by a microsurgical description of the anatomy of the impacted region.
Key Highlights
- Contributions from an impressive group of internationally renowned neurosurgeons and otolaryngologists specializing in skull base pathologies
- Indications, preoperative and postoperative concerns, nuances, pitfalls, tactics, techniques, and references for further reading provide a comprehensive guide to treatment
- A stepwise description of the approach, high-quality four-color drawings, and illustrative cases facilitate acquisition and retention of knowledge
- High-quality figures provide greater visual insights and step-by-step guidance on how to perform specific procedures
This unique textbook will help residents, fellows, and practitioners in neurosurgery and otolaryngology make an evidenced-based decision on using the most effective microsurgical and/or endoscopic approach to achieve the best outcomes in patients with skull base lesions.
This book includes complimentary access to a digital copy on [...]
Inhaltsverzeichnis
Section I: Instrumentals and Equipment
1. Instrumentation for Endoscopic Skull Base Surgery
2. Neurosurgical Instrumentation
3. Neurophysiological Monitoring in Skull Base Surgery
Section II: Anterior Transnasal and Transoral Approaches
4. Anatomical Landmarks of Anterior Approaches: An Endoscopic View
5. Direct Microscopic Transsphenoidal Surgery with Hybrid Use of Endoscopy
6. The Extended Transphenoidal Approach (Mid-maxillotomy) to the Clivus
7. The Microsurgical Transoral Approach
8. Elongated and Pediculated Pericranial Flap for Endonasal Reconstruction of the Entire Ventral Skull Base
9. Expanded Endoscopic Endonasal Approaches to the Sellar and Parasellar Regions
10. The Endoscopic Transpterygoid Approach to the Parasellar and Infratemporal Fossa
11. Endoscopic Endonasal Transclival Approach to the Posterior Fossa
Section III: Surgical Approaches to the Orbit
12. Microsurgical Anatomy of the Orbit
13. Lateral Orbitotomy Approach to the Orbit and Cavernous Sinus
14. Transcranial Approaches to the Orbit
15. The Medial Endoscopic Approach to the Orbit
Section IV: Anterior Approaches to the Skull Base
16. Microsurgical Anatomy of the Anterior Skull Base Through a Cranial View
17. Microsurgical Anatomy of the Anterior Skull Base as Seen Through the Endonasal Endoscopic View
18. Eyebrow Supraorbital Approach for Skull Base Lesions
19. Transbasal/Transcranial Microsurgical Approaches to Anterior Fossa Meningiomas
20. Orbitocranial Approach
21. The Extended Endoscopic Endonasal Approach to the Anterior Fossa
Section V: Anterolateral Approaches
22. Microsurgical Anatomy of the Cavernous Sinus
23. Transcavernous Approach
24. Microsurgical Anatomy of the Middle Fossa and Petrous Apex
25. Pterional Approach
26. Anterolateral Skull Base: Anatomy, Surgical Technique, and Nuances
27. Pretemporal Approach
28. Cranio-Orbit-Zygomatic (COZ) Approach
29. Anterior Petrosal Approach
30. Endoscopic Approach to the Cavernous Sinus Area: Surgical Technique
Section VI: Posterolateral Approaches
31. Temporal Bone Anatomy
32. Microsurgical Anatomy of the Jugular Foramen
33. Anatomy of the Cerebellopontine Angle: A Microscopic Perspective
34. The Posterior Retrolabyrinthine Presigmoid Approach
35. Retrosigmoid Approach
36. Endoscopic Assisted Approach to the Cerebellopontine Angle
37. Infratemporal Fossa Approach to the Jugular Foramen
38. The Facial Reanimation: Multidisciplinary Approaches
Section VII: Posterior and Lateral Approaches to the Craniocervical Junction
39. Microsurgical Anatomy of the Foramen Magnum
40. Far-Lateral Approach and Its Variants
41. Surgical Treatment for Atlantoaxial Instability
42. Endoscopic Approach to the Craniocervical Junction
Section VIII: Approaches to the Posterior Incisural Space
43. Anatomy of the Posterior Incisural Space: Microscopic Perspective
44. Anatomy of the Posterior Incisural Space: Endoscopic Perspective
45. The Occipito-polar Approach: Study of the Occipital lnterhemispheric Supratentorial Transtentorial Transfalcine Approach
46. Supracerebellar Infratentorial Approach: Microsurgical Perspective
47. Supracerebellar Infratentorial Approach: Endoscopic Perspective
48. Supracerebellar Transtentorial Approach
Section IX: Cerebrovascular Management for Skull Base Surgery
49. STA-MCA Bypass
50. High-Flow Cervical Carotid Artery to Middle Cerebral Artery Bypass
51. Intracranial Intracranial Bypass for Treatment of Complex Vascular Lesions and Tumors
52. Endoscopic Endonasal Approaches for the Treatment of Vascular Lesions
1. Instrumentation for Endoscopic Skull Base Surgery
2. Neurosurgical Instrumentation
3. Neurophysiological Monitoring in Skull Base Surgery
Section II: Anterior Transnasal and Transoral Approaches
4. Anatomical Landmarks of Anterior Approaches: An Endoscopic View
5. Direct Microscopic Transsphenoidal Surgery with Hybrid Use of Endoscopy
6. The Extended Transphenoidal Approach (Mid-maxillotomy) to the Clivus
7. The Microsurgical Transoral Approach
8. Elongated and Pediculated Pericranial Flap for Endonasal Reconstruction of the Entire Ventral Skull Base
9. Expanded Endoscopic Endonasal Approaches to the Sellar and Parasellar Regions
10. The Endoscopic Transpterygoid Approach to the Parasellar and Infratemporal Fossa
11. Endoscopic Endonasal Transclival Approach to the Posterior Fossa
Section III: Surgical Approaches to the Orbit
12. Microsurgical Anatomy of the Orbit
13. Lateral Orbitotomy Approach to the Orbit and Cavernous Sinus
14. Transcranial Approaches to the Orbit
15. The Medial Endoscopic Approach to the Orbit
Section IV: Anterior Approaches to the Skull Base
16. Microsurgical Anatomy of the Anterior Skull Base Through a Cranial View
17. Microsurgical Anatomy of the Anterior Skull Base as Seen Through the Endonasal Endoscopic View
18. Eyebrow Supraorbital Approach for Skull Base Lesions
19. Transbasal/Transcranial Microsurgical Approaches to Anterior Fossa Meningiomas
20. Orbitocranial Approach
21. The Extended Endoscopic Endonasal Approach to the Anterior Fossa
Section V: Anterolateral Approaches
22. Microsurgical Anatomy of the Cavernous Sinus
23. Transcavernous Approach
24. Microsurgical Anatomy of the Middle Fossa and Petrous Apex
25. Pterional Approach
26. Anterolateral Skull Base: Anatomy, Surgical Technique, and Nuances
27. Pretemporal Approach
28. Cranio-Orbit-Zygomatic (COZ) Approach
29. Anterior Petrosal Approach
30. Endoscopic Approach to the Cavernous Sinus Area: Surgical Technique
Section VI: Posterolateral Approaches
31. Temporal Bone Anatomy
32. Microsurgical Anatomy of the Jugular Foramen
33. Anatomy of the Cerebellopontine Angle: A Microscopic Perspective
34. The Posterior Retrolabyrinthine Presigmoid Approach
35. Retrosigmoid Approach
36. Endoscopic Assisted Approach to the Cerebellopontine Angle
37. Infratemporal Fossa Approach to the Jugular Foramen
38. The Facial Reanimation: Multidisciplinary Approaches
Section VII: Posterior and Lateral Approaches to the Craniocervical Junction
39. Microsurgical Anatomy of the Foramen Magnum
40. Far-Lateral Approach and Its Variants
41. Surgical Treatment for Atlantoaxial Instability
42. Endoscopic Approach to the Craniocervical Junction
Section VIII: Approaches to the Posterior Incisural Space
43. Anatomy of the Posterior Incisural Space: Microscopic Perspective
44. Anatomy of the Posterior Incisural Space: Endoscopic Perspective
45. The Occipito-polar Approach: Study of the Occipital lnterhemispheric Supratentorial Transtentorial Transfalcine Approach
46. Supracerebellar Infratentorial Approach: Microsurgical Perspective
47. Supracerebellar Infratentorial Approach: Endoscopic Perspective
48. Supracerebellar Transtentorial Approach
Section IX: Cerebrovascular Management for Skull Base Surgery
49. STA-MCA Bypass
50. High-Flow Cervical Carotid Artery to Middle Cerebral Artery Bypass
51. Intracranial Intracranial Bypass for Treatment of Complex Vascular Lesions and Tumors
52. Endoscopic Endonasal Approaches for the Treatment of Vascular Lesions
Details
| Medium: | Bundle |
|---|---|
| Inhalt: |
1 MP3, Download oder Online
1 Buch |
| ISBN-13: | 9781626239661 |
| ISBN-10: | 1626239665 |
| Sprache: | Englisch |
| Herstellernummer: | 892966 |
| Ausstattung / Beilage: | Hardback (Thread Stitching) |
| Autor: |
Borba, Luis
de Oliveira, Jean |
| Hersteller: | Thieme, Stuttgart |
| Verantwortliche Person für die EU: | Georg Thieme Verlag KG, Oswald-Hesse-Straße 50, D-70469 Stuttgart, info@thieme.de |
| Abbildungen: | Beilage: Video |
| Maße: | 35 x 225 x 290 mm |
| Von/Mit: | Luis Borba (u. a.) |
| Erscheinungsdatum: | 07.12.2021 |
| Gewicht: | 1,724 kg |
Inhaltsverzeichnis
Section I: Instrumentals and Equipment
1. Instrumentation for Endoscopic Skull Base Surgery
2. Neurosurgical Instrumentation
3. Neurophysiological Monitoring in Skull Base Surgery
Section II: Anterior Transnasal and Transoral Approaches
4. Anatomical Landmarks of Anterior Approaches: An Endoscopic View
5. Direct Microscopic Transsphenoidal Surgery with Hybrid Use of Endoscopy
6. The Extended Transphenoidal Approach (Mid-maxillotomy) to the Clivus
7. The Microsurgical Transoral Approach
8. Elongated and Pediculated Pericranial Flap for Endonasal Reconstruction of the Entire Ventral Skull Base
9. Expanded Endoscopic Endonasal Approaches to the Sellar and Parasellar Regions
10. The Endoscopic Transpterygoid Approach to the Parasellar and Infratemporal Fossa
11. Endoscopic Endonasal Transclival Approach to the Posterior Fossa
Section III: Surgical Approaches to the Orbit
12. Microsurgical Anatomy of the Orbit
13. Lateral Orbitotomy Approach to the Orbit and Cavernous Sinus
14. Transcranial Approaches to the Orbit
15. The Medial Endoscopic Approach to the Orbit
Section IV: Anterior Approaches to the Skull Base
16. Microsurgical Anatomy of the Anterior Skull Base Through a Cranial View
17. Microsurgical Anatomy of the Anterior Skull Base as Seen Through the Endonasal Endoscopic View
18. Eyebrow Supraorbital Approach for Skull Base Lesions
19. Transbasal/Transcranial Microsurgical Approaches to Anterior Fossa Meningiomas
20. Orbitocranial Approach
21. The Extended Endoscopic Endonasal Approach to the Anterior Fossa
Section V: Anterolateral Approaches
22. Microsurgical Anatomy of the Cavernous Sinus
23. Transcavernous Approach
24. Microsurgical Anatomy of the Middle Fossa and Petrous Apex
25. Pterional Approach
26. Anterolateral Skull Base: Anatomy, Surgical Technique, and Nuances
27. Pretemporal Approach
28. Cranio-Orbit-Zygomatic (COZ) Approach
29. Anterior Petrosal Approach
30. Endoscopic Approach to the Cavernous Sinus Area: Surgical Technique
Section VI: Posterolateral Approaches
31. Temporal Bone Anatomy
32. Microsurgical Anatomy of the Jugular Foramen
33. Anatomy of the Cerebellopontine Angle: A Microscopic Perspective
34. The Posterior Retrolabyrinthine Presigmoid Approach
35. Retrosigmoid Approach
36. Endoscopic Assisted Approach to the Cerebellopontine Angle
37. Infratemporal Fossa Approach to the Jugular Foramen
38. The Facial Reanimation: Multidisciplinary Approaches
Section VII: Posterior and Lateral Approaches to the Craniocervical Junction
39. Microsurgical Anatomy of the Foramen Magnum
40. Far-Lateral Approach and Its Variants
41. Surgical Treatment for Atlantoaxial Instability
42. Endoscopic Approach to the Craniocervical Junction
Section VIII: Approaches to the Posterior Incisural Space
43. Anatomy of the Posterior Incisural Space: Microscopic Perspective
44. Anatomy of the Posterior Incisural Space: Endoscopic Perspective
45. The Occipito-polar Approach: Study of the Occipital lnterhemispheric Supratentorial Transtentorial Transfalcine Approach
46. Supracerebellar Infratentorial Approach: Microsurgical Perspective
47. Supracerebellar Infratentorial Approach: Endoscopic Perspective
48. Supracerebellar Transtentorial Approach
Section IX: Cerebrovascular Management for Skull Base Surgery
49. STA-MCA Bypass
50. High-Flow Cervical Carotid Artery to Middle Cerebral Artery Bypass
51. Intracranial Intracranial Bypass for Treatment of Complex Vascular Lesions and Tumors
52. Endoscopic Endonasal Approaches for the Treatment of Vascular Lesions
1. Instrumentation for Endoscopic Skull Base Surgery
2. Neurosurgical Instrumentation
3. Neurophysiological Monitoring in Skull Base Surgery
Section II: Anterior Transnasal and Transoral Approaches
4. Anatomical Landmarks of Anterior Approaches: An Endoscopic View
5. Direct Microscopic Transsphenoidal Surgery with Hybrid Use of Endoscopy
6. The Extended Transphenoidal Approach (Mid-maxillotomy) to the Clivus
7. The Microsurgical Transoral Approach
8. Elongated and Pediculated Pericranial Flap for Endonasal Reconstruction of the Entire Ventral Skull Base
9. Expanded Endoscopic Endonasal Approaches to the Sellar and Parasellar Regions
10. The Endoscopic Transpterygoid Approach to the Parasellar and Infratemporal Fossa
11. Endoscopic Endonasal Transclival Approach to the Posterior Fossa
Section III: Surgical Approaches to the Orbit
12. Microsurgical Anatomy of the Orbit
13. Lateral Orbitotomy Approach to the Orbit and Cavernous Sinus
14. Transcranial Approaches to the Orbit
15. The Medial Endoscopic Approach to the Orbit
Section IV: Anterior Approaches to the Skull Base
16. Microsurgical Anatomy of the Anterior Skull Base Through a Cranial View
17. Microsurgical Anatomy of the Anterior Skull Base as Seen Through the Endonasal Endoscopic View
18. Eyebrow Supraorbital Approach for Skull Base Lesions
19. Transbasal/Transcranial Microsurgical Approaches to Anterior Fossa Meningiomas
20. Orbitocranial Approach
21. The Extended Endoscopic Endonasal Approach to the Anterior Fossa
Section V: Anterolateral Approaches
22. Microsurgical Anatomy of the Cavernous Sinus
23. Transcavernous Approach
24. Microsurgical Anatomy of the Middle Fossa and Petrous Apex
25. Pterional Approach
26. Anterolateral Skull Base: Anatomy, Surgical Technique, and Nuances
27. Pretemporal Approach
28. Cranio-Orbit-Zygomatic (COZ) Approach
29. Anterior Petrosal Approach
30. Endoscopic Approach to the Cavernous Sinus Area: Surgical Technique
Section VI: Posterolateral Approaches
31. Temporal Bone Anatomy
32. Microsurgical Anatomy of the Jugular Foramen
33. Anatomy of the Cerebellopontine Angle: A Microscopic Perspective
34. The Posterior Retrolabyrinthine Presigmoid Approach
35. Retrosigmoid Approach
36. Endoscopic Assisted Approach to the Cerebellopontine Angle
37. Infratemporal Fossa Approach to the Jugular Foramen
38. The Facial Reanimation: Multidisciplinary Approaches
Section VII: Posterior and Lateral Approaches to the Craniocervical Junction
39. Microsurgical Anatomy of the Foramen Magnum
40. Far-Lateral Approach and Its Variants
41. Surgical Treatment for Atlantoaxial Instability
42. Endoscopic Approach to the Craniocervical Junction
Section VIII: Approaches to the Posterior Incisural Space
43. Anatomy of the Posterior Incisural Space: Microscopic Perspective
44. Anatomy of the Posterior Incisural Space: Endoscopic Perspective
45. The Occipito-polar Approach: Study of the Occipital lnterhemispheric Supratentorial Transtentorial Transfalcine Approach
46. Supracerebellar Infratentorial Approach: Microsurgical Perspective
47. Supracerebellar Infratentorial Approach: Endoscopic Perspective
48. Supracerebellar Transtentorial Approach
Section IX: Cerebrovascular Management for Skull Base Surgery
49. STA-MCA Bypass
50. High-Flow Cervical Carotid Artery to Middle Cerebral Artery Bypass
51. Intracranial Intracranial Bypass for Treatment of Complex Vascular Lesions and Tumors
52. Endoscopic Endonasal Approaches for the Treatment of Vascular Lesions
Details
| Medium: | Bundle |
|---|---|
| Inhalt: |
1 MP3, Download oder Online
1 Buch |
| ISBN-13: | 9781626239661 |
| ISBN-10: | 1626239665 |
| Sprache: | Englisch |
| Herstellernummer: | 892966 |
| Ausstattung / Beilage: | Hardback (Thread Stitching) |
| Autor: |
Borba, Luis
de Oliveira, Jean |
| Hersteller: | Thieme, Stuttgart |
| Verantwortliche Person für die EU: | Georg Thieme Verlag KG, Oswald-Hesse-Straße 50, D-70469 Stuttgart, info@thieme.de |
| Abbildungen: | Beilage: Video |
| Maße: | 35 x 225 x 290 mm |
| Von/Mit: | Luis Borba (u. a.) |
| Erscheinungsdatum: | 07.12.2021 |
| Gewicht: | 1,724 kg |
Sicherheitshinweis
Ähnliche Produkte
Taschenbuch
Lieferzeit 4-7 Werktage
Buch
Aktuell nicht verfügbar
Taschenbuch
Lieferzeit 4-7 Werktage
Buch
Lieferzeit 2-3 Wochen
Buch
Lieferzeit 2-3 Wochen
Buch
Aktuell nicht verfügbar
Buch
Aktuell nicht verfügbar
Buch
Aktuell nicht verfügbar
Taschenbuch
