Acta Neurochir DOI 10.1007/s00701-014-2125-6
HOW I DO IT - NEUROSURGICAL TECHNIQUES
Full endoscopic endonasal expanded approach to the petroclival region: optimizing the carotid-clival window Juan Antonio Simal-Julián & Pablo Miranda-Lloret & Carlos Botella-Asunción & Armin Kassam
Received: 27 February 2014 / Accepted: 1 May 2014 # Springer-Verlag Wien 2014
Abstract Background The petroclival junction (PCJ) is a challenging skull base location from neurosurgical point of view, especially if the retrocarotid space has to be reached. Method In response to this challenge, this report provides a detailed full description of the endoscopic endonasal expanded approach (EEA) to the petroclival region and retrocarotid space. We present the technique step by step, introducing a critical concept about the optimization of the petroclival drilling, generating the carotid-clival window (CCW). The CCW is delimited by the paraclival segment of the internal carotid artery ICA anterolaterally, the petrous bone posterolaterally, the clival dura medially, the synchondrosis inferiorly, and the cavernous sinus superiorly; therefore, this approach exposes an important nuance to augment the previous approaches for PCJ and retrocarotid space. Conclusion This technique provides a good surgical window and carries minimal risk.
Keywords Chordoma . Clivus . Endonasal . Endoscope . Petroclival junction
Electronic supplementary material The online version of this article (doi:10.1007/s00701-014-2125-6) contains supplementary material, which is available to authorized users. J. A. Simal-Julián (*) Neurosurgical Department. HUiP La Fe de Valencia, Blv Sur, Valencia, S/N 46026, Spain e-mail: [email protected] P. Miranda-Lloret : C. Botella-Asunción Neurosurgical Department HUyP La Fe, Valencis, Spain A. Kassam SpainNeurosurgical Department. HUyP La Fe de Valencia, Valencia, Spain
This approach modification can generate the widest CCW to work through with two hands and under 0° or low-angle optics, entering from the contralateral nostril. Additional cases and more evidence are needed to refine this surgical technique. The endoscopic approach to the petrous apex, and mid- and lower clivus has been described in the last few years, but the extension to the retrocarotid space, with respect to the paraclival and lacerum internal carotid artery (ICA) segments, involves a surgical challenge. In response to this challenge, this work defines the full endoscopic endonasal approach (EEA) to the petroclival region in our surgical practice, introducing the concept of optimizing the carotid-clival window.
Relevant surgical anatomy From the endoscopic point of view, the ICA can be divided into intrapetrous, lacerum, paraclival, and parasellar segments. The petroclival junction (PCJ) is a dihedral angle (Fig. 1B), in other words, an angle between two planes, one formed by the clival surface comprising the lateral wall of the mid-clivus and another formed by the petrosal surface, delimited superomedially by the transition of the parasellar-paraclival segment of the ICA, inferolaterally by the lacerum segment of the ICA, and superolaterally by the line connecting these two points, which corresponds to the paraclival segment of the ICA. After drilling both faces, the petroclival angle is converted into an only oblique plane, which we call the CCW. The CCW is delimited by the paraclival segment of the ICA anterolaterally, the petrous bone posterolaterally, the paraclival segment of the ICA laterally, the clival dura medially, the petrooccipital synchondrosis inferiorly, and the cavernous sinus superiorly (Fig. 1A). Therefore, exposing an important nuance to augment the approaches for clival region and retrocarotid space. The abducens nerve (VI) pierces the
Acta Neurochir
Fig. 1 A: Surgical anatomy. B: PCJ diagram
dura between the periosteal and meningeal layers of the petroclival dura that form the walls of the inferior petrosal sinus (interdural segment) and enters into Dorello’s canal. Specific perioperative considerations Neuronavigation system was employed with contrast multislice CT images. After orotracheal intubation, the patient was placed in a supine position, with his neck stretched and head turned 10° sideways towards the left shoulder with a Mayfield cephalostat. Cervical dissection was performed to provide proximal control of the right ICA. Cottonoids soaked with tetracaine chlorhydrate and adrenaline were introduced through both nostrils for 15 min. We did not use external lumbar drainages after this approach. A postoperative MRI will be performed within 3 days after surgery, 1, 3, 6 and 12 months, and then yearly. Information about postoperative nasal follow-up in the ENT clinics is explained to the patient, consisting of an early examination after packing removal and then weekly thereafter, depending on the crusting process.
plane. Full-depth drilling of the mid-clivus provided broad exposure of the lateral clival surface. At this step, the interdural segment of the VI is at risk. Particular attention is needed to prevent thermal injury during drilling. Inferior petrosal sinus injury can be controlled with hemostatic foam. Next we proceed to drill the petrosal surface of the PCJ. Thus, the PCJ can be exposed maximally, allowing us to manipulate under 0° optic lenses in the retrocarotid space, which are more intuitive and practical than angulated ones. If a dural opening is needed at this level, incising the dura at the midline is recommended because the VI would be several millimeters off the midline.
Closure Closure was performed by using Duragen© and the nasoseptal flap as vascularized flap. A Folley balloon was placed in the nose for 3 days.
Description of the technique (video) (ESM 1) The endonasal procedure was performed using a Karl Storz© 0° rigid endoscope. Right mid- and inferior turbinectomies were performed. The nasoseptal flap (NSF) was raised and the posterior half of the septum was dissected to enable work using both nostrils and four hands. Then, sphenoidotomy was performed, taking away the sphenoid floor all the way to the clival recess. Left antrostomy and removal of the posterior wall of the maxillary sinus was performed. After transposing the pterygopalatine fossa, the pterygoid wedge was exposed and the vidian foramen was observed. The vidian nerve (VN) is a fundamental anatomical landmark for locating the ICA. Drilling between the three and nine o’clock positions centered on the vidian foramen is safe and avoids any vascular damage. The sphenoid floor was drilled such that the anterior face of the lacerum foramen, sphenoid floor, and mid-clivus were situated in the same
Fig. 2 Pre- and postoperative images
Acta Neurochir
Indications The most common indications for extension to the PCJ are cholesterol granuloma cysts, epidermoid cysts, chordomas, and chondrosarcomas. Comparatively, the Kawase approach entails some degree of extradural brain retraction, and its inferior limit of exposure can’t be extended easily along the petrooccipital synchondrosis or lower clivus. Limitations Limitations to this approach are related to the cranial nerves. Concretely, the internal acoustic canal would be its posterolateral margin, but the VII and VIII cranial nerves in their intrameatal or cisternal segments couldn’t be surpassed. On other hand, poorly pneumatizated sphenoid patterns may result in relative contraindications. How to avoid complications It’s worth highlighting four aspects to prevent complications: 1) Early cervical proximal control of the ICA; 2) optimization of the CCW; 3) use of vascularized flaps. Case illustration Because clival insufflation of the tumor makes the approach easier, we have selected a pure petroclival chordoma without significant clival expansion to illustrate (Fig. 2A, B). Macroscopically gross total resection was possible without complications (Fig. 2C, D).
CSF leak is low when the closure is performed with vascularized flaps (5.4 %). 1. Early proximal control of the cervical ICA is recommended when the ICA encasement is suspected. 2. We opt for reconstruction with NSF. 3. The VN is the landmark for locating the ICA lacerum. 4. Full-depth drilling of the mid-clivus provides broad exposure of the lateral clival surface. 5. Optimization of the CCW is mandatory to control the resection limits. 6. We avoid mobilization of the ICA segments because liberating a segment to be transposed for so long is very costly, carries a high risk, and its mobilization capacity is limited. 7. The CCW is enough to work through with two hands and under 0° or low-angle optics from the contralateral nostril. 8. Working under visual circumstances with 70° angulated lenses doesn’t facilitate dissection or bimanual manipulation. 9. EEA accomplishes the main principles of the skull base surgery: remove as much bone as needed to avoid brain retraction. 10. Higher complete resection and lower complication rates may be hoped after EEA than for open surgery [2].
Conflicts of interest None.
Specific information to give to the patient about surgery & potential risks
References
The patient must give written consent for the planned endoscopic procedures. The complication rate of the endoscopic endonasal expanded approach has been established as low [1] and include infection (1.9 %), neurological deficit (1.8 %), and potential risk of vascular injury (< 1 %, in cases of extension into the coronal plane, about 5.4 %). The risk of
1. Kassam AB, Prevedello DM, Carrau RL, Snyderman CH, Thomas A, Gardner P, Zanation A, Duz B, Stefko ST, Byers K, Horowitz MB (2011) Endoscopic endonasal skull base surgery: analysis of complications in the authors’ initial 800 patients. J Neurosurg 114(6):1544–68 2. Komotar RJ, Starke RM, Raper DM, Anand VK, Schwartz TH (2011) The endoscope-assisted ventral approach compared with open microscope-assisted surgery for clival chordomas. World Neurosurg 76:318–27
HOW I DO IT - NEUROSURGICAL TECHNIQUES
Full endoscopic endonasal expanded approach to the petroclival region: optimizing the carotid-clival window Juan Antonio Simal-Julián & Pablo Miranda-Lloret & Carlos Botella-Asunción & Armin Kassam
Received: 27 February 2014 / Accepted: 1 May 2014 # Springer-Verlag Wien 2014
Abstract Background The petroclival junction (PCJ) is a challenging skull base location from neurosurgical point of view, especially if the retrocarotid space has to be reached. Method In response to this challenge, this report provides a detailed full description of the endoscopic endonasal expanded approach (EEA) to the petroclival region and retrocarotid space. We present the technique step by step, introducing a critical concept about the optimization of the petroclival drilling, generating the carotid-clival window (CCW). The CCW is delimited by the paraclival segment of the internal carotid artery ICA anterolaterally, the petrous bone posterolaterally, the clival dura medially, the synchondrosis inferiorly, and the cavernous sinus superiorly; therefore, this approach exposes an important nuance to augment the previous approaches for PCJ and retrocarotid space. Conclusion This technique provides a good surgical window and carries minimal risk.
Keywords Chordoma . Clivus . Endonasal . Endoscope . Petroclival junction
Electronic supplementary material The online version of this article (doi:10.1007/s00701-014-2125-6) contains supplementary material, which is available to authorized users. J. A. Simal-Julián (*) Neurosurgical Department. HUiP La Fe de Valencia, Blv Sur, Valencia, S/N 46026, Spain e-mail: [email protected] P. Miranda-Lloret : C. Botella-Asunción Neurosurgical Department HUyP La Fe, Valencis, Spain A. Kassam SpainNeurosurgical Department. HUyP La Fe de Valencia, Valencia, Spain
This approach modification can generate the widest CCW to work through with two hands and under 0° or low-angle optics, entering from the contralateral nostril. Additional cases and more evidence are needed to refine this surgical technique. The endoscopic approach to the petrous apex, and mid- and lower clivus has been described in the last few years, but the extension to the retrocarotid space, with respect to the paraclival and lacerum internal carotid artery (ICA) segments, involves a surgical challenge. In response to this challenge, this work defines the full endoscopic endonasal approach (EEA) to the petroclival region in our surgical practice, introducing the concept of optimizing the carotid-clival window.
Relevant surgical anatomy From the endoscopic point of view, the ICA can be divided into intrapetrous, lacerum, paraclival, and parasellar segments. The petroclival junction (PCJ) is a dihedral angle (Fig. 1B), in other words, an angle between two planes, one formed by the clival surface comprising the lateral wall of the mid-clivus and another formed by the petrosal surface, delimited superomedially by the transition of the parasellar-paraclival segment of the ICA, inferolaterally by the lacerum segment of the ICA, and superolaterally by the line connecting these two points, which corresponds to the paraclival segment of the ICA. After drilling both faces, the petroclival angle is converted into an only oblique plane, which we call the CCW. The CCW is delimited by the paraclival segment of the ICA anterolaterally, the petrous bone posterolaterally, the paraclival segment of the ICA laterally, the clival dura medially, the petrooccipital synchondrosis inferiorly, and the cavernous sinus superiorly (Fig. 1A). Therefore, exposing an important nuance to augment the approaches for clival region and retrocarotid space. The abducens nerve (VI) pierces the
Acta Neurochir
Fig. 1 A: Surgical anatomy. B: PCJ diagram
dura between the periosteal and meningeal layers of the petroclival dura that form the walls of the inferior petrosal sinus (interdural segment) and enters into Dorello’s canal. Specific perioperative considerations Neuronavigation system was employed with contrast multislice CT images. After orotracheal intubation, the patient was placed in a supine position, with his neck stretched and head turned 10° sideways towards the left shoulder with a Mayfield cephalostat. Cervical dissection was performed to provide proximal control of the right ICA. Cottonoids soaked with tetracaine chlorhydrate and adrenaline were introduced through both nostrils for 15 min. We did not use external lumbar drainages after this approach. A postoperative MRI will be performed within 3 days after surgery, 1, 3, 6 and 12 months, and then yearly. Information about postoperative nasal follow-up in the ENT clinics is explained to the patient, consisting of an early examination after packing removal and then weekly thereafter, depending on the crusting process.
plane. Full-depth drilling of the mid-clivus provided broad exposure of the lateral clival surface. At this step, the interdural segment of the VI is at risk. Particular attention is needed to prevent thermal injury during drilling. Inferior petrosal sinus injury can be controlled with hemostatic foam. Next we proceed to drill the petrosal surface of the PCJ. Thus, the PCJ can be exposed maximally, allowing us to manipulate under 0° optic lenses in the retrocarotid space, which are more intuitive and practical than angulated ones. If a dural opening is needed at this level, incising the dura at the midline is recommended because the VI would be several millimeters off the midline.
Closure Closure was performed by using Duragen© and the nasoseptal flap as vascularized flap. A Folley balloon was placed in the nose for 3 days.
Description of the technique (video) (ESM 1) The endonasal procedure was performed using a Karl Storz© 0° rigid endoscope. Right mid- and inferior turbinectomies were performed. The nasoseptal flap (NSF) was raised and the posterior half of the septum was dissected to enable work using both nostrils and four hands. Then, sphenoidotomy was performed, taking away the sphenoid floor all the way to the clival recess. Left antrostomy and removal of the posterior wall of the maxillary sinus was performed. After transposing the pterygopalatine fossa, the pterygoid wedge was exposed and the vidian foramen was observed. The vidian nerve (VN) is a fundamental anatomical landmark for locating the ICA. Drilling between the three and nine o’clock positions centered on the vidian foramen is safe and avoids any vascular damage. The sphenoid floor was drilled such that the anterior face of the lacerum foramen, sphenoid floor, and mid-clivus were situated in the same
Fig. 2 Pre- and postoperative images
Acta Neurochir
Indications The most common indications for extension to the PCJ are cholesterol granuloma cysts, epidermoid cysts, chordomas, and chondrosarcomas. Comparatively, the Kawase approach entails some degree of extradural brain retraction, and its inferior limit of exposure can’t be extended easily along the petrooccipital synchondrosis or lower clivus. Limitations Limitations to this approach are related to the cranial nerves. Concretely, the internal acoustic canal would be its posterolateral margin, but the VII and VIII cranial nerves in their intrameatal or cisternal segments couldn’t be surpassed. On other hand, poorly pneumatizated sphenoid patterns may result in relative contraindications. How to avoid complications It’s worth highlighting four aspects to prevent complications: 1) Early cervical proximal control of the ICA; 2) optimization of the CCW; 3) use of vascularized flaps. Case illustration Because clival insufflation of the tumor makes the approach easier, we have selected a pure petroclival chordoma without significant clival expansion to illustrate (Fig. 2A, B). Macroscopically gross total resection was possible without complications (Fig. 2C, D).
CSF leak is low when the closure is performed with vascularized flaps (5.4 %). 1. Early proximal control of the cervical ICA is recommended when the ICA encasement is suspected. 2. We opt for reconstruction with NSF. 3. The VN is the landmark for locating the ICA lacerum. 4. Full-depth drilling of the mid-clivus provides broad exposure of the lateral clival surface. 5. Optimization of the CCW is mandatory to control the resection limits. 6. We avoid mobilization of the ICA segments because liberating a segment to be transposed for so long is very costly, carries a high risk, and its mobilization capacity is limited. 7. The CCW is enough to work through with two hands and under 0° or low-angle optics from the contralateral nostril. 8. Working under visual circumstances with 70° angulated lenses doesn’t facilitate dissection or bimanual manipulation. 9. EEA accomplishes the main principles of the skull base surgery: remove as much bone as needed to avoid brain retraction. 10. Higher complete resection and lower complication rates may be hoped after EEA than for open surgery [2].
Conflicts of interest None.
Specific information to give to the patient about surgery & potential risks
References
The patient must give written consent for the planned endoscopic procedures. The complication rate of the endoscopic endonasal expanded approach has been established as low [1] and include infection (1.9 %), neurological deficit (1.8 %), and potential risk of vascular injury (< 1 %, in cases of extension into the coronal plane, about 5.4 %). The risk of
1. Kassam AB, Prevedello DM, Carrau RL, Snyderman CH, Thomas A, Gardner P, Zanation A, Duz B, Stefko ST, Byers K, Horowitz MB (2011) Endoscopic endonasal skull base surgery: analysis of complications in the authors’ initial 800 patients. J Neurosurg 114(6):1544–68 2. Komotar RJ, Starke RM, Raper DM, Anand VK, Schwartz TH (2011) The endoscope-assisted ventral approach compared with open microscope-assisted surgery for clival chordomas. World Neurosurg 76:318–27
