Proptosis

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This presentation discusses otolaryngological aspects of proptosis

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Proptosis

  1. 1. ProptosisBalasubramanian Thiagarajan Otolaryngology online
  2. 2. Definition Proptosis is defined as abnormal protrusion of eye ball If protrusion of globe is 18 mm / less it is known as proptosis If protrusion of globe is more than 18 mm it is known as exophthalmos Proptosis + lid lag = exopthalmos Otolaryngology online
  3. 3. Exorbitism This is caused due to decrease in the volume of orbit causing the orbital contents to protrude forwards Usually bilateral Should be differentiated from proptosis / exophthalmos Otolaryngology online
  4. 4. Difference between proptosis / exophthalmos Otolaryngology online
  5. 5. Anatomy of orbit  Volume of orbit is fixed  30 ml  Increase in soft tissue volume of 5 ml will cause 5 mm of proptosis Otolaryngology online
  6. 6. Anatomy of orbit - 2  Resembles a four sided pyramid  Rim is 40 mm horizontally and 35 mm in an adult male  Medial walls are parallel and 25 mm apart in adults  Lateral orbital walls angle about 90 degrees from each other Otolaryngology online
  7. 7. Orbital rim Superior orbital rim is formed by frontal bone Inferior rim is formed by maxillary bone medially and zygomatic bone laterally Lateral orbital rim is formed by zygoma Superior rim contains a notch at the junction of medial and lateral thirds (supraorbital notch) Medial portion of the rim is formed by frontal process of maxilla Otolaryngology online
  8. 8. Lacrimal fossa  Lodges the lacrimal sac  This fossa is formed by maxillary and lacrimal bones  Bounded by anterior and posterior lacrimal crests  Anterior crest is formed by maxillary bone  Posterior lacrimal crest is formed by lacrimal bone Otolaryngology online
  9. 9. Webers suture Lies anterior to lacrimal fossa Also known as sutura longitudinalis imperfecta This suture runs parallel to anterior lacrimal crest Infraorbital nerve artery branches pass through it to supply nasal mucosa Bleeding occurs from these vessels during lacrimal sac surgeries Otolaryngology online
  10. 10. Embryology 7 bones involved in the formation of orbit are derived from neural crest cells Ossification of orbit is complete at birth excepting its apex Lesser wing of sphenoid is cartilagenous Other bones undergo membranous ossification Otolaryngology online
  11. 11. Orbital roof Formed by frontal bone Posterior 1.5 cms of the roof is formed by lesser wing of sphenoid Optic foramen contains optic nerve Optic nerve enters orbit at an angulation of 44 degrees Lacrimal gland is located at the lateral end of orbital roof Otolaryngology online
  12. 12. Medial orbital wall Formed by frontal process of maxilla, lacrimal bone, ethmoidal bone and lesser wing of sphenoid Thinest portion of medial wall is the lamina papyracea It separates orbit from the nasal cavity Infections from ethmoidal sinuses can breach this bone and spread into the orbit. Otolaryngology online
  13. 13. Medial wall of orbit applied anatomy Lacrimal bone at the level of lacrimal fossa is very thin This bone can easily be penetrated during endoscopic DCR If the maxillary component is predominant then it is really difficult to breach this bone during endoscopic DCR since this bone is rather thick. Otolaryngology online
  14. 14. Fronto ethmoidal suture line Very important surgical landmark Marks the approximate level of ethmoidal roof Dissection above this line will expose the cranial cavity Anterior and posterior ethmoidal foramina are present in this suture line Anterior and posterior ethmodial arteries pass throught these foramina Otolaryngology online
  15. 15. Orbital roof Roof of orbit is formed by frontal bone Posterior 1.5 cm of roof is formed by lesser wing of sphenoid Optic foramen is located in the lesser wing of sphenoid Otolaryngology online
  16. 16. Floor of orbit It is the shortest of all the walls Bounded laterally by infraorbital fissure Medially bounded by maxilloethmoidal strut of bone Almost entirely formed by orbital plate of maxilla with minor contribution from orbital plate of palatine bone posteriorly Floor is thin medial to infra orbital groove Infraorbital groove becomes infraorbital foramen anteriorly Otolaryngology online
  17. 17. Lateral wall Formed by greater wing of sphenoid Zygoma & zygomatic process of frontal bone – minor contribution Recurrent meningeal branch of middle meningeal artery is seen in this wall 4-5 mm behind the lateral orbital rim and 1 cm inferior to the fronto zygomatic suture line lie the whitnalls tubercle. Otolaryngology online
  18. 18. Whitnalls tubercle (structures attached) Lateral canthal tendon Lateral rectus check ligament Suspensory ligament of lower eyelid (Lockwoods ligament) Orbital septum Lacrimal gland fascia Otolaryngology online
  19. 19. Anatomical relationship of orbit with paranasal sinuses By its location – it is closely related to all paranasal sinuses By venous drainage – Both these areas share a common venous drainage Otolaryngology online
  20. 20. Peculiarities of orbital venous drainage Entire venous system is devoid of valves – hence two way communication between orbit and sinuses is a reality Superior opthalmic vein connects facial vein to cavernous sinus – causing spread of infections from face to cavernous sinus Inferior ophthalmic vein communicates with pterygoid venous plexus and cavernous sinus by its two branches Otolaryngology online
  21. 21. Pseudoproptosis High myopia Enophthalmos of one eye may cause apparant proptosis of the other one Otolaryngology online
  22. 22. Exophthalmometer  Hertels mirror exophthalmometer is used for this purpose  The distance between the lateral orbital rim and the corneal apex is used as a measure for proptosis  This distance is normally 18 mm Otolaryngology online
  23. 23. ENT - Causes Mnemonic – VEINV – Vascular causesE – Endocrine causesI – Inflammatory causesN – Neoplastic causes Otolaryngology online
  24. 24. Imaging  CT / MRI may help in identifying the cause  Fat in the orbit serves as a contrast medium  3 mm cuts is ideal  Ultrasound – A mode / B mode can be done to identify the causeOtolaryngology online
  25. 25. Role of MRI MRI is sensitive in identifying extraocular muscle oedema Increased T2 relaxation time indicates extraocular muscle oedema, these pts respond well to steroid therapy Patients with normal T2 relaxation levels need orbital decompression Otolaryngology online
  26. 26. Vascular causes Classified into arterial and venous Venous causes are due to dilated veins – Positional proptosis is the classical feature in these patients. It can also be induced by valsalva maneuver Initially there may be atrophy of fat in these pts causing enophthalmos CT scan after jugular vein compression is diagnostic Surgery is disastrous in these patients. Conservative management is the best modality Otolaryngology online
  27. 27. Proptosis due to dural venous sinus fistula Shunt is low flow type Proptosis is insidiuous and often goes unnoticed A high index of suspicion is necessary to diagnose these cases Otolaryngology online
  28. 28. Carotid cavernous fistula High flow shunts Can occur spontaneously / trauma Subjective bruit / proptosis / chemosis / vision loss Arterolization of conjunctival vessels causing corkscrew pattern Intractable cases – shunt must be closed using balloon / carotid artery ligation Otolaryngology online
  29. 29. Endocrine proptosis - features Presence of lid lag / retraction Presence of temporal flare in upper eyelid Presence of orbital congestion Imaging shows enlarged extraocular muscles, bulging of orbital septum due to fat protrusion Otolaryngology online
  30. 30. Inflammatory causes Idiopathic inflammation – Pseudotumor of orbit Due to specific causes of orbital inflammation These pts have pain during ocular movement Associated dacryo adenitis + Perioptic neuritis can cause blindness Steroids may be helpful Otolaryngology online
  31. 31. Neoplastic lesions involving nose and sinuses Inverted papilloma Fungal infections Mucoceles of paranasal sinuses Fibrous dysplasia of maxilla Osteomas involving frontal / ethmoidal sinuses JNA Otolaryngology online
  32. 32. Otolaryngology online
  33. 33. Management Low dose irradiation (rarely used) Surgery Otolaryngology online
  34. 34. Indications for orbital decompression Visual disturbance due to proptosis Failure of steroids to improve vision If steroids are necessary on a long term basis for maintaining vision To preven exposure keratitis Diplopia Cosmesis Otolaryngology online
  35. 35. Risks of orbital decompression Diplopia Intractable strabismus Hypoglobus Injury to optic nerve due to prolonged globe retraction Retrobular hematoma – this can cause blindness Injury to infraorbital nerve Epistaxis Otolaryngology online
  36. 36. Orbital decompression (Goals) To enlarge the confining space of orbit by removing 1-4 of its walls 15 mm of decompression can be achieved by removing all 4 walls of the orbit Usually successful surgery causes 3-7 mm decompression of orbit Otolaryngology online
  37. 37. Superior orbital decompression Naffzeiger technique Superior wall decompression Complete unroofing of orbit – frontal craniotomy Large amounts of bone can be removed creating more space Craniotomy may be needed Used in pts with orbital trauma Otolaryngology online
  38. 38. Naffzeiger --- Contd In collaboration with neurosurgeon Optic nerve should be visualized to begin with The roof of the orbit is removed starting from the optic foramen to the anterosuperior orbital rim Periosteum should be left intact to prevent injury to levator muscle H shaped incision is made over superior periosteum allowing orbital fat to prolapse through it Titanium mesh can be used online cover orbital roof Otolaryngology to
  39. 39. Medial orbital decompression Also known as Sewell procedure Coronal incision / external ethmoidectomy incision Medial canthal tendon is identified and divided Anterior and posterior ethmoidal arteries identified and clipped Complete ethmoidectomy is performed starting from lacrimal fossa Otolaryngology online
  40. 40. Bicoronal incision for medial orbital decompression Medial canthal tendon can be left intact Ethmoidectomy is performed from above Lacrimal sac and trochlea should not be damaged Medial periosteum is incised and orbital fat is allowed to prolapse into the nasal cavity Otolaryngology online
  41. 41. Inferior decompression Hisch and Urbanek procedure Artificial creation of blow out fracture of orbital floor sparing infra orbital nerve Trans conjunctival / subciliary incision plus Caldwell Luc procedure Laterally floor can be removed up to zygoma and medially up to lacrimal fossa Posteriorly bone is thick – 3 cms of bone can be removed from this area Otolaryngology online
  42. 42. Inferior decompression -- Contd Periosteum is incised to allow orbital fat to prolapse into the maxillary antrum Forced duction test should be performed to ensure orbital muscles are not entrapped. Otolaryngology online
  43. 43. Lateral decompression Kronlein procedure Coronal incision, and lateral extension of subciliary incision Extended lateral canthotomy Lateral orbital rim periosteum is exposed from zygomatic arch to zygomatico frontal suture Periosteum incised along lateral orbital rim and orbital fat is teased out Otolaryngology online
  44. 44. Combination of approaches Any of the above said approaches can be combined for optimal benefit Combination of apporaches reduces the surgical risk and provides more increase of space than one procedure alone Otolaryngology online
  45. 45. Endoscopic decompression Inferior and medial orbital walls can be accessed easily using nasal endoscope A large middle meatal antrostomy is performed – 30 degree endoscope is used to identify the position of inferior orbital nerve in the roof of maxillary sinus Total ethmoidectomy is performed Sphenoid osteum is identified and enlarged Otolaryngology online
  46. 46. Endoscopic decompression ---Contd Lamina papyracea is exposed Position of anterior & posterior ethmoid arteries noted If middle turbinate is resected it helps in post op cleaning. If left behind it prevents excessive collapse of orbital fat Lamina papyacea is remove bit by bit using Freers elevator. It should be cracked in the middle portion first Otolaryngology online
  47. 47. Endocopic decompression --- Contd Initially periorbita is left intact to prevent orbital fat prolapse which could obstruct vision Bone is to be removed up to the roof of the ethmoid superiorly, face of the sphenoid posteriorly, the nasolacrimal duct anteriorly. Inferiorly it can be removed up to maxillary antrostomy Small piece of bone is retained over frontal recess area to prevent orbital fat obstruction frontal sinus drainage Otolaryngology online
  48. 48. contd Starting posteriorly periorbita is incised Sickle knife is kept superficial to avoid injury to extraocular muscles Mutliple cuts are made in the periorbita allowing orbital fat to prolapse into the nasal cavity Exophthalmos of up to 3.5 mm can be corrected by endoscopic decompression Nasal packing is to be avoided to prevent optic nerve compression Otolaryngology online
  49. 49. Tips Nose blowing is to be avoided for 2 weeks following surgery Bilateral decompression should be done within an interval of a week For mild exophthalmos 2-3 mm any of the approaches would suffice For moderate – 3-5mm inferior decompression is sufficient For severe ones – 5-7 mm three wall decompression is preferred Otolaryngology online
  50. 50. Thank You Otolaryngology online

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