Dissection by Toma Spiriev, MD, PhD, FEBNS
Part of these dissections are published as open access papers in J Neurol Surg B Skull Base:
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One Piece Orbitozygomatic Approach Based on the Sphenoid Ridge Keyhole: Anatomical Study
Toma Spiriev, Lars Poulsgaard, Kaare Fugleholm
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Techniques for Preservation of the Frontotemporal Branch of Facial Nerve during Orbitozygomatic Approaches
Toma Spiriev, Lars Poulsgaard, Kaare Fugleholm
Part of these dissections are published as open access papers in J Neurol Surg B Skull Base:
follow link:
One Piece Orbitozygomatic Approach Based on the Sphenoid Ridge Keyhole: Anatomical Study
Toma Spiriev, Lars Poulsgaard, Kaare Fugleholm
follow link:
Techniques for Preservation of the Frontotemporal Branch of Facial Nerve during Orbitozygomatic Approaches
Toma Spiriev, Lars Poulsgaard, Kaare Fugleholm
Fig. 1, 2 and 3
Skin incision and the course of the frontal branch (FB) of the facial nerve. The skin incision starting at the zygomatic arch continues to the superior temporal line, curves just behind the hairline and reaches the midline. A larger skin incision would allow less retraction of the flap and avoid retraction-induced injury to the FB. The course of the frontal branch of facial nerve is outlined crossing the zygomatic arch app. 2 cm from the tragus (range 0,8-3,1 cm).
Skin incision and the course of the frontal branch (FB) of the facial nerve. The skin incision starting at the zygomatic arch continues to the superior temporal line, curves just behind the hairline and reaches the midline. A larger skin incision would allow less retraction of the flap and avoid retraction-induced injury to the FB. The course of the frontal branch of facial nerve is outlined crossing the zygomatic arch app. 2 cm from the tragus (range 0,8-3,1 cm).
Fig. 4
The entire course of the frontal branch and the facial nerve trunk is carefully dissected. The FB of the facial nerve is crossing the zygomatic arch approximately 2.0 cm from the tragus and gives one main branch running just above the galea and several small branches in the fat pad above the superficial leaflet of the temporalis fascia. Red line is presenting the course of the superfical temporalis fascia split.
The entire course of the frontal branch and the facial nerve trunk is carefully dissected. The FB of the facial nerve is crossing the zygomatic arch approximately 2.0 cm from the tragus and gives one main branch running just above the galea and several small branches in the fat pad above the superficial leaflet of the temporalis fascia. Red line is presenting the course of the superfical temporalis fascia split.
Fig. 5 and 6
The interfascial dissection is safe to be started from the most anterior part of the superior temporal line where the two fasciae are continuous and dissection is extended to the root of the zygoma. The interfascial fad pad is elevated and the dissection is kept close to the deep temporalis fascia.
The interfascial dissection is safe to be started from the most anterior part of the superior temporal line where the two fasciae are continuous and dissection is extended to the root of the zygoma. The interfascial fad pad is elevated and the dissection is kept close to the deep temporalis fascia.
Fig. 7
The entire course of the facial nerve is carefully dissected. The FB of the facial nerve is crossing the zygomatic arch approximately 2.0 cm from the tragus and gives one main branch running just above the galea and several small branches in the fat pad above the superficial leaflet of the temporalis fascia. Red line is presenting the course of superfical temporalis fascia split .
The entire course of the facial nerve is carefully dissected. The FB of the facial nerve is crossing the zygomatic arch approximately 2.0 cm from the tragus and gives one main branch running just above the galea and several small branches in the fat pad above the superficial leaflet of the temporalis fascia. Red line is presenting the course of superfical temporalis fascia split .
Fig. 8, 9 and 10
The subfascial dissection is started with the identification of the superficial leaflet of the temporalis fascia with the beggining of the skin incision. The superficial temporalis fascia is incised to the muscle fibers and the dissection is continued between the muscle and the deep temporalis fascia. By this way both fasciae are elevated together with the fat pad. On the superior temporal line a fascial cuff is left used for later closure.
The subfascial dissection is started with the identification of the superficial leaflet of the temporalis fascia with the beggining of the skin incision. The superficial temporalis fascia is incised to the muscle fibers and the dissection is continued between the muscle and the deep temporalis fascia. By this way both fasciae are elevated together with the fat pad. On the superior temporal line a fascial cuff is left used for later closure.
Fig. 11 and 12
Final view after the interfascial dissection and subfascial dissections are completed. Both techniques allow for appropriate zygoma exposure need later for the OZ approaches.
Final view after the interfascial dissection and subfascial dissections are completed. Both techniques allow for appropriate zygoma exposure need later for the OZ approaches.
Fig. 13, 14, 15
Temporalis muscle incision, which allows full mobilization of the muscle. The retrograde muscle dissection allows for preservation of the deep neurovascular structures.
Temporalis muscle incision, which allows full mobilization of the muscle. The retrograde muscle dissection allows for preservation of the deep neurovascular structures.
Fig. 16 and 17
The advantages of the retrograde dissection and the deep temporalis artery are presented.
The advantages of the retrograde dissection and the deep temporalis artery are presented.
Fig. 18 and 19
The one piece OZ approach based on the sphenoid ridge key hole.
The one piece OZ approach based on the sphenoid ridge key hole.
Fig. 20, 21, 22
The osteology of the sphenoid ridge is presented. The sphenoid ridge is the natural osseous border between the frontal and temporal lobes and periorbita. This is a thick bone that is usually removed to different extent during anterolateral skull base approaches.
The osteology of the sphenoid ridge is presented. The sphenoid ridge is the natural osseous border between the frontal and temporal lobes and periorbita. This is a thick bone that is usually removed to different extent during anterolateral skull base approaches.
Fig. 23, 24
The sphenoid ridge is easily identifiable landmark on the lateral skull surface. The distance from the center of the sphenoid ridge keyhole (corresponding to the superficial projection on the lateral skull surface of the most anterior and thickest part of the sphenoid ridge) to the following landmarks are presented: Superior temporal line (direct distance) - 2.2 cm (SD 0.22 mm), anterior to the pterion (which approximates the lateral end of the sphenoid ridge) - 2.5cm (SD 0.44 mm). The center of the keyhole was situated 1.07cm (SD 0.08 mm) posterior and 0.71cm (SD 0.22mm) inferior to the fronto-zygomatic suture. The sphenoid ridge burr hole provided early exposure of frontal dura, temporal dura as well as the periorbita.
The sphenoid ridge is easily identifiable landmark on the lateral skull surface. The distance from the center of the sphenoid ridge keyhole (corresponding to the superficial projection on the lateral skull surface of the most anterior and thickest part of the sphenoid ridge) to the following landmarks are presented: Superior temporal line (direct distance) - 2.2 cm (SD 0.22 mm), anterior to the pterion (which approximates the lateral end of the sphenoid ridge) - 2.5cm (SD 0.44 mm). The center of the keyhole was situated 1.07cm (SD 0.08 mm) posterior and 0.71cm (SD 0.22mm) inferior to the fronto-zygomatic suture. The sphenoid ridge burr hole provided early exposure of frontal dura, temporal dura as well as the periorbita.
Fig. 25, 26, 27, 28 and 29
Steps in the bonework for the one piece OZ apporach. After exposure of the frontal and temporal dura separated by sphenoid ridge, the sphenoid ridge is followed anteriorly to the periorbita and superioly to the thickest part of the orbital roof. The craniotomy is as follows: 1) and 2 from temporal exposure to superior temporal line 3) from superior temporal line to to the orbital rim 4) orbital rim cut 5) bone cut from inferior orbital fissure (IOF) to the level of spehnoid ridge. 6) Root of zygoma cut 6) Zygomatic bone cut (at the level of zygomatico-facial foramen.
Steps in the bonework for the one piece OZ apporach. After exposure of the frontal and temporal dura separated by sphenoid ridge, the sphenoid ridge is followed anteriorly to the periorbita and superioly to the thickest part of the orbital roof. The craniotomy is as follows: 1) and 2 from temporal exposure to superior temporal line 3) from superior temporal line to to the orbital rim 4) orbital rim cut 5) bone cut from inferior orbital fissure (IOF) to the level of spehnoid ridge. 6) Root of zygoma cut 6) Zygomatic bone cut (at the level of zygomatico-facial foramen.
Fig. 30, 31 and 32
The last part of the bone work is the orbital roof cut. The orbital roof consist of 2 parts – sphenoidal part which is thick and a paper thin frontal part. The sphenoid ridge burr-hole provides early and direct access to the thickest part of the orbital roof. After removal, the paper thin (frontal) part of the orbital roof could be easily fractured when performing the OZ approaches.
The last part of the bone work is the orbital roof cut. The orbital roof consist of 2 parts – sphenoidal part which is thick and a paper thin frontal part. The sphenoid ridge burr-hole provides early and direct access to the thickest part of the orbital roof. After removal, the paper thin (frontal) part of the orbital roof could be easily fractured when performing the OZ approaches.
Fig. 33, 34 and 35
After the bone flap is removed the frontal, temporal dura as well as the periorbita are exposed. In this specimen the frontal sinus is very well developed and opened. Fig. 34, 35. One piece OZ bone flap.
After the bone flap is removed the frontal, temporal dura as well as the periorbita are exposed. In this specimen the frontal sinus is very well developed and opened. Fig. 34, 35. One piece OZ bone flap.
Fig. 36-41
One piece Fronto-orbital approach is a variation of the frontal full OZ exposure. The same basic steps are followed as presented for the full OZ approach. However, the zygomatic arch is not removed and the final cut. (fig. 38) is done at the level of the angle of the zygoma.
Fig. 40 and 41 present the final view of the bone flap.
One piece Fronto-orbital approach is a variation of the frontal full OZ exposure. The same basic steps are followed as presented for the full OZ approach. However, the zygomatic arch is not removed and the final cut. (fig. 38) is done at the level of the angle of the zygoma.
Fig. 40 and 41 present the final view of the bone flap.
Fig. 42, 43, 44
In addition, the sphenoid ridge as well as part of the temporal bone could be taken as one piece which would allow for easier reconstruction later.
In addition, the sphenoid ridge as well as part of the temporal bone could be taken as one piece which would allow for easier reconstruction later.
Fig. 45-50
The two piece OZ approach is another alternative to the full OZ approach. It allows direct visualization of some of the bone cuts on the orbital rim.
The two piece OZ approach is another alternative to the full OZ approach. It allows direct visualization of some of the bone cuts on the orbital rim.
Fig. 51, 52, 53 and 54
If the pathology requires any part of the orbital rim or the zygomatic arch could be removed. Removal of the orbital rim allows for increase angle of sight and less degree of brain retraction for lesions high in the paresellar area and third ventricle.
If the pathology requires any part of the orbital rim or the zygomatic arch could be removed. Removal of the orbital rim allows for increase angle of sight and less degree of brain retraction for lesions high in the paresellar area and third ventricle.
Fig. 55 and 56
By cutting the zygomatic arch anterior and posterior and leaving it attached to masseter muscle allows for better exposure of the temporal fossa, by further dropping down the temporalis muscle.
By cutting the zygomatic arch anterior and posterior and leaving it attached to masseter muscle allows for better exposure of the temporal fossa, by further dropping down the temporalis muscle.
Fig. 57-58
Before and after dropping down the zygomatic arch. Dropping the zygomatic arch allows for the flattest possible trajectory to the middle fossa and provides lesser degree of brain retraction for pathologies located primary in the middle fossa floor.
Before and after dropping down the zygomatic arch. Dropping the zygomatic arch allows for the flattest possible trajectory to the middle fossa and provides lesser degree of brain retraction for pathologies located primary in the middle fossa floor.
Fig. 59
Reconstruction of the bone flap using low profile mini-plate system
Reconstruction of the bone flap using low profile mini-plate system