CRANIOTOMY FLAPS ,INCISION AND CLOSURE.pptx

Venous drainage of scalp - veins draining the scalp follows a pattern simillar to arteries , of deep parts of scalp .
Scalp consist of 5 layers - skin , subcutaneous tissue, occipitofrontalis, subaponeurotic areolar tissue , pericranium .

1. CRANIOTOMY FLAPS ,INCISION AND CLOSURE.

2. ANATOMIC AND NEUROVASCULAR CONSIDERATION- EXTENT --The scalp extends from the top of the forehead in front to the superior nuchal line behind. Laterally it projects down to the zygomatic arch and external acoustic meatus.

3. BLOOD SUPPLY OF SCALP- ARTERIAL SUPPLY— IN FRONT OF AURICLE— Supratrochlear. Supraorbital. Superficial temporal arteries . BEHIND THE AURICLE— Posterior auricular . Occipital arteries.

4. Layers of scalp - CONSISTS OF FIVE LAYERS – Skin . Subcutaneous tissue . Occipitofrontalis (epicranius) and it’s aponuerosis. Subaponuerotic aereolar tissue . Pericranium.

5. VENOUS DRAINAGE OF SCALP-

6. NERVE SUPPLY OF SCALP-

7. BASIC SURGICAL PRINCIPLES OF CRANIOTOMY-- PREOPERATIVE REVIEW OF PATIENT AND SCANS. PREPARATION OF SCALP. PROPER POSITIONING OF PATIENT. SCALP TOILETING. PROPER DRAPPING. SKIN FLAPS . PLACING OF BURR HOLES , CRANIOTOMY SIZE. DUROTOMY . CLOSURES .

8. PRINCIPLES FOR BONE FLAPS - Most direct access to target. For cerebral convexity directly centered over the lesion. Number of burr holes varies. Separating of underlying dura . If dura is lacerated during cutting ,saw should be turned off and removed backwards via entrance hole.

9. Air cells opened : – Remove the mucosa. Pack with betadine soaked gelfoam. Pack with bone wax. Cover it up with vascularized tissue. Proposed bony cuts over venous sinuses should be done last . Cut sinus can be sewn or tamponade . Bony bleeds are stopped with bone wax. Penfield’s dissector used to separate dura. Epidural tacking sutures to control epidural bleeding before opening dura.

10. OPENING OF DURAMATER -- Manually palpate the dura. Dura opened as straight, curved or flap like incisions. Flaps based towards sinuses. Opened with sharp hook and knife. Incision further opened with dural scissors. Placement of cottonoid along the intended incision. Suitable cuff of dura around the bone for suturing later.

11. CLOSURE OF WOUNDS- Closure in layers. Check for BP, valsalva maneuver. Hitch suture. Water tight but not tension. Bone flap replacement. Skin closed in two layers.

12. TYPES OF CRANIOTOMY- 1-TREPHINE CRANIOTOMY – PROVIDES A CIRCULAR OPENING . LESS TIME CONSUMING. IDEAL FOR EVACUATING POST TRAUMATIC EDH . 2- FLAP CRANIOTOMY – A) FREE BONE FLAP CRANIOTOMY . B)- OSTEOPLASTIC CRANIOTOMY- Bone flap is elevated along with its musculofascial attachment. Believed to be less prone to infection due to intact blood supply of the bone flap.

13. SKIN FLAPS AND CRANIOTOMIES- ANTERIOR SKIN FLAPS AND CRANIOTOMIES- 1- SUPRA ORBITAL KEYHOLE CRANIOTOMY- 2- THE LYNCH HOWARTH INCISON. 3- ORBITOTOMY.

14. SUPRAORBITAL KEY HOLE CRANIOTOMY- In 1900 Krause first demonstrated supra-orbital, subfrontal approach on cadaver, then eight years later he reported the first resection of skull base meningioma through this approach. In 1913, Frazier advocated a supraorbital ridge resection, which was found useful in surgery for pituitary adenomas. In the 1990, Perneczky and colleagues popularized the keyhole concept and the technique commonly used today, the supraorbital keyhole craniotomy. The evolution, however, began with Fedor Krause's . More recently, Jane and Delashaw , described a supraorbital craniotomy in the approach to orbital tumors. Other variants have been proposed by Al-Mefty et al.

15. INDICATIONS- Aneurysm of Anterior circulation except those of distal anterior cerebral artery. For high positioned basilar bifurcation of basilar-Superior cerebellar artery aneurysm. Tumor of anterior cranial fossa, sphenoid ridge. Pathologies of sellar and suprasellar region.

16. POSITIONING- Head is elevated. Head is extended as it allows relaxation of frontal lobe. SKIN INCISION- Type-Superciliary, transciliary, transpalpebral. The incision is made in the lateral 2/3rd of eyebrow.

17. CRANIOTOMY – Supraorbital craniotomy, bone flap with shape of “D”. Dura is opened in semilunar fashion with base at orbital rim. The limitation with the lighting of microscope deep down a narrow corridor can be overcome by Endoscope , which can be held by assistant or retractor arm. A second look with endoscope can also allow visualization of gross resection of lesion.

18. COMPLICATIONS DUE TO INCISION:-- 1. Transient loss of supraorbital sensation(7.5%) . 2. Frontal paresis (5.5%). 3. Opening of frontal sinus can cause CSF leak(4%) . 4. Burning of eyebrow due to microscopic light on 100% intensity. (Not seen with intensity below 70%). 5. Bone flap resorption.

19. VARIANTS OF SUPRAORBITAL CRANIOTOMY- Lateral variation:- To partially remove the lesser sphenoid wing exposing the frontal and temporal dura mater. Also on removing clinoid process, paraclinoid segment of ICA can be visualised. Medial Modification: For surgical view of suprasellar and interhemispheric structure. With possibility of interhemispheric and subfrontal dissection. Basal variation: To gain more oblique view of deep seated prepontine and interpeduncular region via subfrontal exposure after removing orbital rim and partial removal of orbital roof.

20. LYNCH HOWARTH FLAP- Incision made mid way between the nasal dorsum and medial canthus aong the naso facial crease. Used in transetmosphenoidal approach for sellar mass. Common extracranial approach for repair of CSF fistulas of cribriform ,ethmoid and sphenoid region.

21. ORBITOTMY- Orbitotomy refers to surgical approach for an orbital mass lesion.  ANTERIOR ORBITOTOMY. LATERAL ORBITOTOMY. TRANSFRONTAL ORBITOTOMY. TEMPOROFRONTAL ORBITOTMY.

22. ANTERIOR ORBITOTOMY- It is indicated only when the lesion is readily palpable through the eyelids and is judged to be mainly in front of the equator of eyeball. Aproached by superior, inferior,medial and lateral incision.

23. LATERAL ORBITOTMY-  Indictions: Laterally placed extraconal tumours. Intraconal tumours lateral or inferior to the optic nerve. It is useful for lacrimal gland tumours, retrobulbar lesions, such as cavernomas and can be extended for posterior lesions. Advantages: • Good exposure, Well-tolerated procedure. Disadvantages: • Visible but minimal scar.

24. TRANSFRONTAL ORBTITOTOMY Indications: Superiorly and medially placed moderate and small-sized tumours . Intraconal tumours medial to optic nerve. In this technique, orbit is opened through its roof. In this procedure supratrochlear nerve is preserved. The approach to the tumour should be preferably between the superior rectus and medial rectus muscles,to avoid any injury to the branches of the oculomotor nerve. This procedure is particularly useful for tumour to the optic nerve.

25. TEMPOROFRONTAL ORBITOTOMY Indications: All tumours with middle fossa extension. All tumours with infratemporal extension. This approach provides an access to the orbit (through its roof) and anterior and middle cranial fossa simultaneously. Advantages: Minimally invasive, particularly for retention cysts. Disadvantages: • Visible scar, • Risk of infection, • Limited indications.

26. FRONTAL FLAPS- UNILATERAL FRONTAL FLAPS. BICORONAL/BIFRONTAL/SOUTTAR FLAP. FRONTOTEMPORAL FLAP.

27. UNILATERAL FRONTAL FLAP - Exposes anterior frontal lobe. Begins along coronal suture and curves anteriorly along the midline preferably ending at hair line. Earlier names were Fergusson flap or Mc kissock flap.

28. Bicoronal/Souttar flap Large exposures of anterior cranial fossa and sella. Frontotemporal lesions and cranial base. Superior to zygomatic arch 1cm anterior to tragus,extends over the bregma to the corresponding site on the opposite side . Reflect up to orbit rim. Based on Supraorbital/trochlear vessels. Suitable for frontal lobe,subfrontal approaches to anterior skullbase and transcortical access to ventricles.

29. An extended frontal or bifrontal craniotomies for exposure of sella, anterior cranial base. Supine with head extended . Holes placed on either sides of saggital sinus and intervening bone is removed with roneguers or drill . Either removed as single piece or conversion of Frontal flap to bifrontal flap.

30. Advantages of bifrontal flap-- Incision is posterior to hair line so has better cosmetic outcome. Provide widest exposure of the skull on both sides simultaneously.

31. FRONTO- TEMPORAL FLAP (PTERIONAL CRANIOTOMY) Walter dandy concieved the idea of pterional approach . Popularized by Yasargil. Supine position with head end elevated to 30 degrees and rotated by the same to opposite side. Extends from zygoma to 1 to 2 cm off the frontal midline following a curve behind the natural hair line.

32. The pterion is located in the temporal fossa, approximately 2.6 cm behind and 1.3 cm above the posterolateral margin of the frontozygomatic suture. It is the junction between four bones: Parietal bone,  squamous part of temporal bone, greater wing of sphenoid bone, frontal bone. These bones are typically joined by five cranial sutures : the  sphenoparietal suture  joins the sphenoid and parietal bones the  coronal suture  joins the frontal bone to the sphenoid and parietal bones the  squamous suture joins the temporal bone to the sphenoid and parietal bones the  sphenofrontal suture  joins the sphenoid and frontal bones the  sphenosquamosal suture  joins the sphenoid and temporal bones

33. For aneurysms of anterior circulation, basilar top, for tumors of retro orbital, parasellar and subfrontal areas. Bone flap centered over the pterion. Further bone may be removed from the inferior temporal squama and to improve vision, drilling of the sphenoid ridge can be done . Addition of orbito-zygomatic craniotomy ( FTOZ ) will allow for a more lower and anterior approach. Early visualisation of optic nerve and carotid artery .

34. TEMPORAL FLAPS AND CRANIOTOMIES- QUESTION MARK TEMPORAl FLAP. HORSE SHOE SHAPED TEMPORAL FLAP. CUSHINGS LINEAR TEMPORAL FLAP.

35. QUESTION MARK TEMPORAL FLAP- Based on zygoma anterior to tragus and curves up and posteriorly over the ear and extends anteriorly and parallel to superior temporal line to the end of the hair line. To access the anterior temporal region and the subtemporal region.

36. HORSE SHOE TEMPORAL FLAP- Inverted “U” shape with base directed towards vascular supply. With the tragus at the centre. Used for approaching posterior temporal region .

37. CUSHING’S LINEAR FLAP- Straight incision marked 1 cm in front of tragus and extended upwards. Used in evacuation of temporal extra dural hematomas and for temporal lesions.

38. OCCIPITAL FLAP - HORSE SHOE FLAP . MITRE FLAP.

39. OCCIPITAL HORSE SHOE FLAP - Inverted U shape incision based on occipital artery. For occipital lobe lesions and hematomas.

40. MITRE FLAP -  Traditional, ceremonial head-dress of bishops. Inion to vertex vertical limb. Upper limb then falls over posterior parietal region towards the ear. Blood supply from the occipital artery. Occipital lobe, posterior falx and superior tentorial surface.

41. Question mark skin flap (Trauma flap) Cranial trauma, for hemisphere decompression. Exposure to whole hemisphere. Based on zygoma. Blood supply from superior temporal and supraorbital vessels. Curves around 3.5cm posterior to external auditory meatus. Anterior limb extends to hair line .

42. MIDLINE INCISION FOR TRANSCALLOSSAL APPROACH- Incision begin in midline at the hairline ,then upwards with 2/3 rd of incision infront of coronal suture. There after incision curved towards the pinna.

43. INFRATENTORIAL FLAPS AND CRANIOTOMIES- Midline suboccipital craniotomy. Lateral suboccipital craniotomy. Retromastoid suboccipital craniotomy.

44. MIDLINE SUBOCCIPITAL CRANIOTOMY-- INDICATIONS  Cerebellar stroke ,Chiari malformations (symptomatic, large syrinx) , Tumors , Vascular lesions (aneurysms, cavernous malformations, AVMs) , Infections . POSITION  Prone on chest rolls, arms placed by sides . Head in 3-point Mayfield head frame / horseshoe head rest , flexed at neck .

45. INCISION: midline, from inion to C2 spinous process . Expose midline keel, lower part of inion, foramen magnum, C1 lamina.  Craniotomy is done with care to preserve underlying dura. Burr holes can be placed close to transverse sinus or sigmoid sinus just below the superior nuchal line. C1 LAMINECTOMY - Foramen magnum and posterior arch of C1 are exposed till entire width of dura  To reduce risk of vertebral artery injury, electrocautery is not used more than 15 mm lateral to midline when performing subperiosteal dissection of superior posterior ring of C1. 

46. By leaving muscle attachments and laminae of C2 intact, postoperative pain and potential spinal instability (→ cervical kyphosis) are minimized.  Dura is opened in Y or I manner . Watertight closure of dura should be done to prevent formation of psuedomeningocoele.

47. LATERAL SUBOCCIPITAL CRANIOTOMY- INDICATIONS  Exposure of the lateral cerebellar hemisphere, anterolateral brainstem, posterior aspect of petrous bone, craniovertebral junction, and upper cervical cord.  Building block for more extensive procedures, such as the transcondylar, far lateral, extreme lateral, and posterior petrosal approach.  Provides vertebral artery (VA) control, VA can be mobilized from the vertebral sulcus and foramen transversarium of C1.  It provides access to the lateral and sometimes ventral brainstem and cerebellum with minimal retraction. 

48. TECHNIQUE ---- Lateral oblique positioning, head flexed until nuchal muscles become firm  J-shaped or "hockey stick" incision; starts at upper mastoid; leave muscle insertion cuff at superior nuchal line for later closure.  VA lays in the floor of the suboccipital triangle (superior oblique, inferior oblique, and rectus capitis posterior major muscles); transverse process of C1 vertebra can be used as a localizing landmark for the VA. 

49. RETROMASTOID SUBOCCIPITAL CRANIOTOMY- INDICATIONS --- CP angle lesions (acoustic neuroma, MVD for trigeminal neuralgia etc).  POSITIONS- PARK BENCH POSITION -- The head is flexed until the chin is 3CM from the sternum, rotated contra-laterally to the lesion, and flexed 30-degree laterally toward the contralateral shoulder, allowing to increase the angle between the atlas and foramen magnum. SEMISITTING POSITION with neck flexed and face rotated away from side of surgery (ipsilateral tentorium parallel to floor) .

50. ASTERION – sigmoid-transverse sinus junction most commonly (but not always) lies at anteriorly-superiorly (so it is safe to drill here if targeting venous sinus angle) . Landmark- on the line from root of zygoma to inion where it is intersected with vertical line just behind mastoid process. 

51. INCISIONS- Vertical or slightly curvilinear ( lazy-S ) vertically behind auricle, 1-2 fingerbreadths behind hairline central incision third behind ear (1/3 of incision is above transverse-sigmoid junction and 2/3 is below) . Dr. Graham uses vertical incision just beyond digastric groove.  Dr. Broaddus uses lazy-C incision and lower portion goes rather low on neck.  Lazy lambda” just above asterion: 

52. CRANIOTOMY  FOR MVD - small oval retrosigmoid craniectomy FOR VESTIBULAR SCHWANNOMA – larger craniotomy, extend along sigmoid sinus and posteriorly to allow cerebellar retraction.  EXTENDED RETROSIGMOID CRANIOTOMY  Adding bony skeletonization of the sigmoid and transverse sinuses with additional mastoidectomy.  Permits access to areas that are difficult to access with the classic approach—ventral to the brainstem and near the tentorium.