The concepts and surgical trajectories of the extreme lateral infrajugular transcondylar-transtubercular exposure (ELITE) and the transjugular approach are totally different.
ELITE is a dorsolateral approach to the jugular tubercle that requires an anterior reflection of the posterior neck muscles. The surgical approach is from posterior to anterior exposing the condyle dorsally. On the other hand, the posterior infratemporal fossa transjugular approach is an anterolateral approach for the jugular bulb and infrajugular region that requires a posterior reflection of the posterior neck muscles. The surgical approach is from anterior to the transverse process of the C1 with the surgeon exposing the high cervical region between the C1 and the pharynx. The ELITE approach is useful for vertebral basilar artery junction aneurysms, low clival and ventral foramen magnum lesions, and intradural jugular foramen tumors.
Fig. 19.1 (Step 1) Positioning and skin incision.The head is placed in a lateral position and the mastoid tip and posterior border of the body of the mastoid are marked. The skin is cut in a lazy “S” shape with the top of the “S” just below the asterion. The center of the opening is the occipital condyle. The condyle lies medial and inferior to the mastoid tip. (As, asterion; MT, mastoid tip)Fig. 19.2 Exposing the fascia.The fascia on the sternocleidomastoid muscle is exposed.Fig. 19.3 Harvesting a fascial graft.An oval of fascia is harvested to achieve a watertight dural closure at the end of the case. (SCM, sternocleidomastoid muscle)Fig. 19.4 (Step 2) Exposure of sternocleidomastoid muscle.The sternocleidomastoid muscle can be seen after the fascia is removed. At the time of surgery the posterior neck muscles on the occipital bone should be cut as a mass using the monopolar coagulator along to the black line drawn in the figure. In this dissection, each muscle will be exposed to demonstrate the layers of the posterior neck muscles. (SCM, sternocleidomastoid muscle)Fig. 19.5 Exposing the splenius capitis muscle.ELITE is a dorsolateral approach. All the posterior neck muscles on the occipital bone should be reflected anteriorly. After the sterno-cleidomastoid muscle is cut and reflected anteriorly, the splenius capitis muscle can be seen. (SCM, sternocleidomastoid muscle; SpCM, splenius capitis muscle)Fig. 19.6 Exposing the longissimus capitis muscle and the styloid diaphragm.Anterior reflection of the splenius capitis muscle exposes the longissimus capitis muscle inferiorly. A thick layer of fascia known as the styloid diaphragm will be seen below the splenius muscle. Beneath the fascia the surgeon will nd the occipital artery and several veins embedded in a thin layer of fat. (LgCM, longissimus capitis muscle; OA, occipital artery)Fig. 19.7 Exposing the semispinalis capitis muscle.Anterior reflection of the longissimus capitis muscle reveals the styloid diaphragm. The styloid diaphragm covers the middle layer of the posterior neck muscles. The deep muscular layer that consists of the obliquus capitis superior, obliquus capitis inferior, rectus capitis major, and rectus capitis minor muscles lies medial to this styloid diaphragm. (SsCM, semispinalis capitis muscle)Fig. 19.8 Exposing the obliquus capitis superior muscle.After posterior reflection of the semispinalis capitis muscle and removal of the styloid diaphragm the obliquus capitis superior muscle that originates between the superior and inferior nuchal lines can be seen. The vertebral artery lies below the inferior border of this muscle, so the surgeon should be careful if a bovie cautery is being used to cut the superior oblique muscle. (OCSM, obliquus capitis superior muscle)Fig. 19.9 (Step 3) Exposure of occipital bone.After anterior reflection of the obliquus capitis superior muscle the occipital bone is exposed. A lateral suboccipital craniotomy with partial mastoidectomy is performed. (DG, digastric groove)Fig. 19.10 Identifying the inferior retrosigmoid point.To avoid the injury of the vertebral artery the inferior retrosigmoid point (arrow, A) the most caudal (inferior) and posterior edge of the sigmoid sinus should be identi ed. This is the rst landmark in identifying the vertebral artery. (A, inferior retrosigmoid point; SS, sigmoid sinus)Fig. 19.11 Occluding the condylar emissary vein.The posterior condylar emissary vein is found posterior to the occipital condyle. This vein connects the vertebral venous plexus with the sigmoid sinus passing through a foramen in the condyle. Bleeding is controlled either by cauterizing and dividing this vein or by packing the foramen with oxidized cellulose and bone wax. (A, inferior retrosigmoid point; CEV, condylar emissary vein; SS, sigmoid sinus)Fig. 19.12 Opening the foramen magnum.The foramen magnum is opened posterior to the occipital condyle. The foramen magnum is skeletonized back to the posterior point (B; the point that marks the most posterior extent of the foramen magnum). (A, inferior retrosigmoid point; B, foramen magnum posterior point; SS, sigmoid sinus)Fig. 19.13 Relationship between the occipital condyle and posterior condylar emissary vein.The posterior condylar emissary vein that drains into the inferior point of the sigmoid sinus originates in the condylar fossa and passes through the condylar canal. Although it is running in the wrong direction, the condylar canal may be mistaken for the hypoglossal canal. (A, inferior retrosigmoid point; B, foramen magnum posterior point; CEV, condylar emissary vein; OC, occipital condyle)Fig. 19.14 Identifying the posterior notch of C1.When the vertebral artery is difficult to find, it can be localized by the following measurements. The posterior point of the foramen magnum (B) lies approximately 30 mm dorsal to the inferior retrosigmoid point (A). The posterior tubercle of C1 (C) lies 10 mm inferior to the posterior point of the foramen magnum (B). The J-groove lies lateral to the posterior tubercle. (A, inferior retrosigmoid point; B, foramen magnum posterior point; C, C1 posterior point)Fig. 19.15 Identifying the J-groove of C1.The surgeon follows the posterior arch of C1 laterally until a depression (J-groove) is found on its superior surface. This groove (point D) marks the location of the vertebral artery. Care should be taken not to damage the venous plexus surrounding the vertebral artery. (A, inferior retrosigmoid point; B, foramen magnum posterior point; C, C1 posterior point; D, J-groove of the C1; JG, J-groove for the vertebral artery; PA, posterior arch of the C1 [atlas])Fig. 19.16 (Step 4) Identification of horizontal (V3) segment of vertebral artery.The vertebral artery is identifled at the J-groove of C1 surrounded by the paravertebral venous plexus. Clinically severe venous bleeding can result from injury of this venous sleeve. Absorbable hemostatic agent packing and bipolar cautery are effective for stopping the bleeding. (C1C, C1 condyle; OC, occipital condyle; PA, posterior arch of the C1 [atlas]; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.17 Overview of landmarks used to identify the vertebral artery and occipital and C1 condyle.The distances between A and B is 30.5 ± 5.6 mm (21.5, 40.5 mm); B and C, 10.4 ± 2.3 mm (6.0, 14.0 mm); C and D, 19.1 ± 3.8 mm (12.5, 24.5 mm). (A, inferior retrosigmoid point; B, foramen magnum posterior point; C, C1 posterior point; C1C, C1 condyle; D, J-groove of the C1; OC, occipital condyle; PA, posterior arch of the C1 [atlas]; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.18 (Step 5) Partial resection of occipital condyleThe microscope should be tilted laterally to remove the posterior medial corner of the occipital condyle. The occipital C1 joint is left intact and the occipital condyle superior to the joint is removed. (C1C, C1 condyle; OC, occipital condyle; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.19 The venous plexus in the hypoglossal canal.The hypoglossal canal runs above the occipital C 1 joint. A thick venous plexus covers the dural sleeve that lies in the bony hypoglossal canal. (HEV, hypoglossal emissary vein; JT, jugular tubercle; VA, vertebral artery)Fig. 19.20 (Step 6) Exposure of hypoglossal canalAfter drilling the cortical bone of the occipital condyle, the cancellous bone is encountered. As the cancellous bone is removed a blue shadow running almost parallel to the joint is encountered. This bony canal inside the cancellous bone is the bony hypoglossal canal. The hypoglossal nerve is covered by the dura and the dura is covered by a venous plexus. This venous plexus around the hypoglossal dural sleeve gives a blue hue seen through the thinned cortical bone. The posterior condylar canal harboring the posterior condylar vein should not be confused with the condylar canal. (HC, hypoglossal canal; JT, jugular tubercle; OC, occipital condyle; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.21 Locating the jugular tubercleThe jugular tubercle is found above the hypoglossal canal. (HC, hypoglossal canal; JT, jugular tubercle; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.22 (Step 7) Drilling of jugular tubercleRemoving the jugular tubercle affords the surgeon a more anterior view of the medulla and lower pons. Removing the most anterior potion of the jugular tubercle is difficult because of the overhanging sigmoid sinus. The tubercle should be carefully removed with a diamond drill cooled by irrigation. Rupture or burning of the superior dura can injure the lower cranial nerves. (JT, jugular tubercle; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.23 Completion of drilling of the jugular tubercle.The jugular tubercle extends anteriorly for about 15 mm. Complete removal of the jugular tubercle is difficult, but the more tubercle removed the farther anterior the surgeon will see. (HC, hypoglossal canal; JT, jugular tubercle; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.24 Final view of the extradural exposure.The relationship between the jugular tubercle and the adjacent structures is demonstrated. (HC, hypoglossal canal; JT, jugular tubercle; OC, occipital condyle; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.25 (Step 8) Opening the dura.A semilunar incision is made in the dura. The inferior corner of the incision is first opened to reach the lateral medullary cistern. Releasing cerebrospinal uid from this cistern allows the cerebellum to fall away from the dura, which reduces the risk of cerebellar injury.Fig. 19.26 Surgical view before removing the jugular tubercle.Figures 19.26 and 19.27are included to demonstrate the advantage the surgeon gains by flattening the jugular tubercle. (IX, glossopharyngeal nerve; VII, facial nerve; VIII, cochlear nerve; X, vagus nerve; XI, accessory nerve)Fig. 19.27 Surgical view after removing the jugular tubercle.The obstruction created by the jugular tubercle is not observed. The surgical view is improved for operations that involve the region of the anterior pontomedullary junction. (VII, facial nerve; VIII, cochlear nerve; X, vagus nerve; XI, accessory nerve)Fig. 19.28 Identifying the spinal accessory nerve, posterior inferior cerebellar, and vertebral arteries.The spinal accessory nerve is usually the rst structure seen in the lateral medullary cistern. Opening the cistern exposes the vertebral artery and the posterior inferior cerebellar artery. (IX, glossopharyngeal nerve; PICA, posterior inferior cerebellar artery; VA, vertebral artery; X, vagus nerve; XI, accessory nerve)Fig. 19.29 Identifying the origin of the posterior inferior cerebellar artery.For operations of the vertebral posterior inferior cerebellar artery junction aneurysm, the origin of posterior inferior cerebellar artery (PICA) must be seen. The hypoglossal nerves are frequently close to the origin of PICA. (IX, glossopharyngeal nerve; PICA, posterior inferior cerebellar artery; VA, vertebral artery; X, vagus nerve; XI, accessory nerve; XII, hypoglossal nerve)Fig. 19.30 Identifying the lower cranial nerves as they exit the jugular foramen.The glossopharyngeal, vagus, and accessory nerves can be seen passing toward the jugular foramen. The jugular tubercle, which underlies these nerves, has been removed. (IX, glossopharyngeal nerve; VA, vertebral artery; X, vagus nerve; XI, accessory nerve)Fig. 19.31 Identifying the vestibulocochlear and facial nerves and the anterior inferior cerebellar artery.The vestibulocochlear and facial nerves are seen rostral to the lower cranial nerves. (AICA, anterior inferior cerebellar artery; IX, glossopharyngeal nerve; VI, abducens nerve; VII, facial nerve; VIII, cochlear nerve; X, vagus nerve; XI, accessory nerve)Fig. 19.32 Identifying the abducens nerve.The abducens nerve can be seen medial to the vestibulocochlear, facial, and lower cranial nerves. The entrance of Dorello’s canal is seen to be parallel to the internal auditory canal (IAC). The relationship between Dorello’s canal and the IAC will depend on the position of the patient’s head. When operating on clival tumors it is best to identify the abducens nerve at the brainstem. (IX, glossopharyngeal nerve; V, trigeminal nerve; VI, abducens nerve; VII, facial nerve; VIII, cochlear nerve; X, vagus nerve)Fig. 19.33 Identifying the origin of the anterior inferior cerebellar artery.The abducens nerve frequently exits from the brainstem close to the origin of the anterior inferior cerebellar artery. (AICA, anterior inferior cerebellar artery; BA, basilar artery; IX, glossopharyngeal nerve; PICA, posterior inferior cerebellar artery; VII, facial nerve; VIII, cochlear nerve; X, vagus nerve; XI, accessory nerve)Fig. 19.34 Identifying the vertebrobasilar junction.Removing the jugular tubercle gives the surgeon a direct view of the basilar vertebral artery junction. (AICA, anterior inferior cerebellar artery; BA, basilar artery; IX, glossopharyngeal nerve; PICA, posterior inferior cerebellar artery; VA, vertebral artery; VI, abducens nerve; X, vagus nerve; XI, accessory nerve)Fig. 19.35 Identifying the opposite vertebral artery.Both vertebral and anterior inferior cerebellar arteries and the vertebrobasilar junction can be seen once the jugular tubercle has been removed. (AICA, anterior inferior cerebellar artery; BA, basilar artery; IX, glossopharyngeal nerve; VA, vertebral artery; X, vagus nerve; XI, accessory nerve)Fig. 19.36 Expanding the view by additional bony resection.The soft tissue extracranial dissection is extended to expose the transverse process of the atlas. The extracranial vertebral artery and the C2 nerve root are well seen. (C1, C1 [atlas]; C1C, C1 condyle; C2N, C2 nerve; OC, occipital condyle; TP, transverse process of the C1 [atlas]; VA, vertebral artery)Fig. 19.37 After removing the C2 nerve root.The vertebral artery is freed from the vertebral canal in the axis. (C1, C1 [atlas]; C1C, C1 condyle; C2, C2 [axis]; OC, occipital condyle; TP, transverse process of the C1 [atlas]; VA, vertebral artery)Fig. 19.38 Overview of the craniovertebral junction.An anatomical relationship around the craniovertebral junction is well demonstrated. (C1, C1 [atlas]; HC, hypoglossal canal; SS, sigmoid sinus; TP, tranverse process of the C1 [atlas]; VA, vertebral artery)Fig. 19.39 Opening the transverse foramen of the atlas.The vertebral artery is freed from the transverse process of the atlas. This is usually done with a diamond drill. Care is taken to avoid opening the perivertebral veins. (HC, hypoglossal canal; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.40 Posterior translocation of the vertebral artery.The vertebral artery is first inspected for severe atherosclerosis. A brittle artery can be a source of emboli, arterial dissection, or rupture when manipulated. If the artery is pliable, it is translocated out of its foramen in the atlas. (HC, hypoglossal canal; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.41 Exposing the anterior arch of the atlas including the facets.Once the artery is translocated, the surgeon has an unobstructed view of the lateral mass of C1. (C1, C1 [atlas]; HC, hypoglossal canal; SS, sigmoid sinus)Fig. 19.42 Drilling the anterior arch and the lateral mass of the atlas.The remainder of the inferior condyle, the occipital-C1 joint, the remainder of the transverse process of C1, and the superior lateral mass of C1 are all removed. (C1C, C1 condyle; F, facet; HC, hypoglossal canal; OC, occipital condyle; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.43 After drilling the anterior arch of the atlas.The surgeon now has access to the ipsilateral anterior arch of C1. (AA, anterior arch of the C1 [atlas]; AS, articular surface; HC, hypoglossal canal; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.44 Exposing the dens.The articulation between the anterior arch of C1 and the dens is exposed. (AA, anterior arch of the C1 [atlas]; Den, dens; HC, hypoglossal canal; SS, sigmoid sinus; VA, vertebral artery)Fig. 19.45 Exposing the articulating surface of the dens.The dissector is inserted into the posterior articular surface of the dens. The drill can be used to remove the dens from the lateral approach. (AA, anterior arch of the C1 [atlas]; Den, dens; HC, hypoglossal canal; (TL, transverse ligament; VA, vertebral artery)Fig. 19.46 Exposing the articulating surface of the dens.The dissector is inserted into the anterior articular surface of the dens. (AA, anterior arch of the C1 [atlas]; Den, dens; HC, hypoglossal canal; VA, vertebral artery)Fig. 19.47 After removing the transverse part of the cruciform ligament.The transverse part of the cruciform ligament is removed to further expose the dens. (AA, anterior arch of the C1 [atlas]; Den, dens; HC, hypoglossal canal; VA, vertebral artery)Fig. 19.48 Drilling the dens.Removing the dens, removing the transverse and superior longitudinal part of the cruciform ligament, and detaching the apical ligament and the alar ligament expose the anterior surface of the dura at the craniocervical junction. (HC, hypoglossal canal; SS, sigmoid sinus)
Only gold members can continue reading. Log In or Register to continue
18 Anatomy for Posterior Skull Base Surgery
20 Lateral Suboccipital Approach: Superior, Middle, and Inferior Cerebellopontine Angle Approach
3 Transfacial Transmaxillary Approach
7 Orbital Approach
12 Middle Fossa Rhomboid Approach (Anterior Petrosectomy)
11 Preauricular Transzygomatic Approach to the Anterior Infratemporal Fossa and Middle Infratemporal Fossa
