Variations of Mucosal-Sparing Septectomy for Endonasal Approach to the Craniocervical Junction

Transcription

1 The Laryngoscope VC 2015 The American Laryngological, Rhinological and Otological Society, Inc. Variations of Mucosal-Sparing Septectomy for Endonasal Approach to the Craniocervical Junction Jean Anderson Eloy, MD, FACS; Alejandro Vazquez, MD; Emily Marchiano, BA; Soly Baredes, MD, FACS; James K. Liu, MD, FACS Objectives/Hypothesis: Recent advances in surgical techniques have rendered the craniocervical junction (CCJ) accessible transnasally. Endoscopic endonasal transclival and transodontoid approaches are routinely performed in leading skull base centers. Usually, these approaches involve a posterior bony and mucosal septectomy, which may compromise the vascularized pedicled nasoseptal flap (PNSF), a robust reconstructive option for repair of large skull base defects. With the possibility of an intraoperative cerebrospinal fluid leak and the reported success of the PNSF for repair of these defects, preserving the integrity of the PNSF is beneficial during the endoscopic endonasal approach to the CCJ. We describe three new variations/refinements of the endoscopic endonasal approach to the CCJ that preserve the mucosal integrity of the posterior nasal septum and PNSF. Methods: Photo and video documentation of cadaveric dissections. Results: The steps required for the different variations in approaching the CCJ are demonstrated. These three options are: 1) nonopposing Killian incisions with submucosal elevation of PNSFs laterally under the inferior turbinates (the PNSFs are retracted laterally and left attached superiorly onto the nasal septum and laterally under the inferior turbinate); 2) bilateral non-opposing PNSFs tucked beneath their respective middle turbinate or into the sphenoid sinus; and 3) a hybrid approach combining option 1 performed on one side and option 2 on the contralateral side. All three options allowed for a mucosal-sparing septectomy to provide ample access to the CCJ. Conclusion: These variations/refinements of the mucosal-sparing approach to the CCJ allowed adequate surgical access with sufficient maneuverability while preserving both PNSFs. Key Words: Craniocervical junction, skull base, skull base approach, endoscopic endonasal transclival approach, endoscopic endonasal transodontoid approach, skull base surgery, endoscopic skull base surgery, nasoseptal flap, posterior septectomy, rheumatoid pannus. Level of Evidence: NA. Laryngoscope, 126: , 2016 INTRODUCTION Advances in surgical techniques have rendered the craniocervical junction (CCJ) accessible endonasally. 1 8 Endoscopic endonasal transclival and transodontoid approaches are now routinely performed in leading skull Additional supporting information may be found in the online version of this article. From the Department of Otolaryngology Head and Neck Surgery (J.A.E., A.V., E.M., S.B., J.K.L.), the Center for Skull Base and Pituitary Surgery, Neurological Institute of New Jersey (J.A.E., S.B., J.K.L.), Department of Neurological Surgery (J.A.E., J.K.L.), and the Department of Ophthalmology and Visual Science (J.A.E.), Rutgers New Jersey Medical School, Newark, New Jersey, U.S.A. Editor s Note: This Manuscript was accepted for publication December 10, Presented as an oral presentation at the 2015 American Rhinologic Society Annual Meeting, Dallas, Texas, U.S.A., September 26, The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Jean Anderson Eloy, MD, FACS, Professor and Vice Chairman, Director, Rhinology and Sinus Surgery, Director, Otolaryngology Research, Co-Director, Endoscopic Skull Base Surgery Program, Department of Otolaryngology Head and Neck Surgery, Professor of Neurological Surgery, Professor of Ophthalmology and Visual Science, Neurological Institute of New Jersey, Rutgers New Jersey Medical School, 90 Bergen St., Suite 8100, Newark, NJ jean. anderson.eloy@gmail.com DOI: /lary base centers and have become an alternative to the transoral approach that historically has been the gold standard. Hence, in a recent systematic review evaluating purely endoscopic endonasal surgery of the CCJ, Fang et al. noted that these approaches resulted in a high rate of neurologic improvement and acceptable complications rate, and concluded that endoscopic endonasal approaches to the CCJ appeared to be a reasonable alternative to the traditional transoral approach in certain cases. 9 These approaches usually involve a posterior bony and mucosal septectomy, which may compromise the integrity of the posterior nasal septum and damage the vascularized pedicled nasoseptal flap (PNSF), a robust reconstructive option that has become the workhorse for repair of large skull base defects over the last 10 years With the possibility of an intraoperative cerebrospinal fluid (CSF) leak and the reported success of the PNSF for repair of these defects, preserving the integrity and maximizing the surface area of the PNSF is beneficial during the endoscopic endonasal approach to the CCJ. Previously, we described a mucosal-sparing technique for the endoscopic endonasal approach to the CCJ that preserves the mucosal integrity of the posterior nasal septum and PNSF. 7 In this report, we use endoscopic endonasal cadaveric 2220

2 dissections with photo and video documentation to describe and provide proof of concept of three additional variations or refinements that achieve the same goal. Each variation represents a distinct option depending on the individual patient s anatomy and pathology. MATERIALS AND METHODS Two fresh cadaveric dissections were performed by two operators using standard endoscopic techniques. Dissection was performed using the Gyrus (Gyrus ACMI, Southborough, MA) standard endoscopic sinus instrumentation. A standard 30- degee endoscope was used throughout the dissection procedures. Stryker (Stryker Neuro Spine ENT, Kalamazoo, MI) power dissector blades and burrs and a standard endoscopic sinus tower were used for video and photo documentation. Surgical Techniques Initially Described Mucosal-Sparing Technique. In our original mucosal-sparing posterior septectomy technique, standard bilateral PNSFs based on the posterior septal branch of the sphenopalatine artery are elevated, with the incisions placed in an offset location. Both PNSFs are fully released from the nasal septum superiorly and inferiorly. In this technique, the anterior limit of the incision determines the PNSF length, which is determined by the expected size and location of the surgical defect and space necessary for adequate instrument triangulation. Each PNSF is then tucked into its ipsilateral middle meatus or sphenoid sinus for protection, and the vascular pedicle is maintained superior to the level of the choana. With the PNSFs elevated, the posterior bony septum is subsequently resected for adequate exposure of the working corridor to the CCJ and to facilitate instrumentation. If the created defect necessitates one or both PNSFs for reconstruction, the flaps are positioned down onto the defect and buttressed with nasal packing. If no CSF leak is encountered, and the PNSFs are not needed for reconstruction, they are returned to their native positions and secured in place with absorbable sutures. Newly Described Variations. The surgical techniques and steps required for the three different variations/refinements to the CCJ are: 1) nonopposing Killian incisions with submucosal elevation of PNSFs laterally under the inferior turbinates (the PNSFs are extended laterally and left attached superiorly onto the nasal septum and laterally under the inferior turbinate); 2) bilateral nonopposing PNSFs tucked beneath their respective middle turbinate; and 3) a hybrid approach combining option 1 performed on one side and option 2 on the contralateral side. All three options are designed to allow the use of binostril and bimanual dissection techniques, with the possibility to use up to four surgical tools simultaneously with adequate surgical freedom. Option 1: Nonopposing Killian Incisions With Submucosal Elevation of Bilateral Pedicled Nasoseptal Flaps Extended and Attached Laterally Under the Inferior Turbinates (Supp. Video 1). This technique involves the creation of bilateral PNSFs that are still attached to the nasal septum superiorly and the floor of the nasal cavity under the inferior turbinate laterally. This procedure starts with lateralization of the inferior and middle turbinates. Killian incisions are then made on each side of the nasal septum at different locations (nonopposing) (Fig. 1 A B). In this technique, the anterior limit of the incision on the nasal septum determines the length of the PNSF (Fig. 1A B), which is estimated based on the expected size and place of the surgical defect, or the amount of space necessary for adequate triangulation of instruments to achieve surgical freedom. Bilateral submucoperichondrial and submucoperiosteal tunnels are then created to elevate the flaps all the way posterior to the choana (Fig. 1C). Submucosal posterior septectomy is then performed to allow binostril and bimanual access for adequate instrument triangulation (Fig. 2D). The two PNSFs are subsequently separated from each other at their posterior most (choanal) connection and along the choanal arch. The PNSFs are then lateralized, and the dissection can continue posteriorly and inferiorly for resection of the clivus and for access to the CCJ (Fig. 2 E F) (Supp. Video 1). During this approach, limited resection of the posterior and lateral aspect of the flaps along the choanal arch, and adequate lateralization of the PNSFs around the area of their sphenopalatine artery pedicles, can significantly improve visualization of the surgical target and allow for better surgical maneuverability. After completion of the resection portion of the procedure, if no CSF leak is encountered and there is no additional need to utilize a PNSF, the flaps are returned to their anatomical position. Although not absolutely necessary, the flaps can be secured in place in their native position using absorbable sutures in a quilting fashion or bilateral silastic splint placement. If the surgical defect necessitates the use of a PNSF, one of the flaps can be released from its superior (nasal septum) and lateral (nasal floor under the inferior turbinate) attachments and rotated posteriorly into the defect site. If only a small and short PNSF is necessary, the side with the most posteriorly located Killian incision can be chosen, and the superior and inferior incisions can be tailored to the adequate PNSF width. If a much larger PNSF is required, the side with the most anterior Killian incision is chosen (for a longer PNSF); the superior incision is made high on the nasal septum and the inferior incision far laterally under the inferior turbinate (for a wider PNSF). Option 2: Bilateral Nonopposing Pedicled Nasoseptal Flaps Tucked into the Middle Meati (Supp. Video 2). This procedure starts by lateralizing the bilateral inferior and middle turbinates. In this mucosal-sparing septectomy approach, we elevate bilateral PNSFs based on the posterior septal branch of the sphenopalatine artery, as described above (Fig. 1A D). As described previously, the anterior limit of the incision on the nasal septum determines the length of the PNSF. Subsequent submucoperichondrial and submucoperiosteal dissection is undertaken posteriorly toward the vascular pedicle. The flaps are then separated posteriorly along the choanal arch (Fig. 2A). Submucosal posterior septectomy is then performed (Fig. 1D). Each PNSF is then released laterally in the area under the inferior turbinate (Fig. 2B) and subsequently tucked into its ipsilateral middle meatus (Fig. 2C) for protection and away from the path to the surgical target; at the same time, the flap pedicles are maintained in a safe location above the level of the choana (Fig. 2D). The dissection can then proceed posteriorly for resection of the floor of the sphenoid/clivus. Great care should be taken to harvest a different size PNSFs on each of the two sides to prevent making the incisions directly opposite each other (i.e., the septal incisions are offset). Care should also be taken to include some of the coverage of the hard palate in the inferior extent of the PNSFs because this allows an easier reapproximation of the PNSFs at the end of the procedure if there is no need to utilize the flaps. Option 3: Hybrid Approach Combining Option 1 Performed on One Side and Option 2 on the Contralateral Side (Supp. Video 3). This hybrid option represents a combination of option 1 performed on one side and option 2 on the other side (Fig. 3). In this technique, after nonopposing Killian incisions and bilateral submucoperichondrial and 2221

3 Fig. 1. Thirty-degree endoscopic photograph depicting a Killian incision (dotted line) on the right nasal septum (A), with a nonopposing Killian incision on the contralateral side placed more posteriorly (B). Right submucoperichondrial and submucoperiosteal tunnel is then created to elevate the PNSF all the way posterior to the sphenoid rostrum (dotted line depicts area of sphenoid sinus) (C). After elevation of the left PNSF, submucosal posterior septectomy is performed to allow binostril and bimanual access for adequate instrument triangulation (D). Sphenoid and clival access is then achieved (E&F). LIT 5 left inferior turbinate; LMT 5 left middle turbinate; NS 5 nasal septum; PNSF 5 pedicled nasoseptal flap; RIT 5 right inferior turbinate; RMT 5 right middle turbinate; Sph 5 sphenoid area. submucoperiosteal tunnels are created; one of the PNSFs is left attached to the nasal septum superiorly and onto the floor of the nasal cavity under the inferior turbinate laterally. The contralateral PNSF is released inferiorly, and a posterior septectomy is achieved. The choanal attachment between the two flaps is released, and the released flap (with inferior cut) is subsequently tucked into the middle meatus. As in the previous two scenarios, if no CSF leak is encountered and there is no additional need for a PNSF after the resection portion of the procedure, the flaps are repositioned to their anatomical position. If the surgical defect requires the use of a PNSF, the flap that was released inferiorly can be additionally released from its superior (nasal septum) attachment and rotated posteriorly into the defect site. DISCUSSION Common traditional approaches to the CCJ include the transoral approach and the extraoral anterolateral transcervical approach The transoral approach 2222

4 Fig. 2. Thirty-degree endoscopic photograph depicting the choanal release (A). Depiction of the released site of the left PNSF (B). (C) Endoscopic view of the positioning of the right PNSF into its ipsilateral middle meatus and access (D) after bilateral tucking of both PNSFs into the middle meati. Ch 5 choana; CR 5 clival recess; HP 5 hard palate; LIT 5 left inferior turbinate; NP 5 nasopharynx; NS 5 nasal septum; PNSF 5 pedicled nasoseptal flap; RIT 5 right inferior turbinate; RMT 5 right middle turbinate; SP 5 soft palate. (still considered the gold standard) has been associated with potential distortion of the tongue or palate and the risk of velopharyngeal insufficiency and longstanding postoperative dysphagia often requiring gastrostomy tube placement. 33,34 Potential problems with this surgical approach includes the need for a tracheostomy, field contamination, and infection leading to wound breakdown. 28,30,31,33,36 Whereas the extraoral anterolateral transcervical approach avoids oropharyngeal contamination, the approach can put the recurrent laryngeal nerve, the esophagus, the trachea, and the carotid sheath with its neurovascular contents at risk. 39,40 The endoscopic endonasal approach to the CCJ has evolved as a less morbid alternative to the previously described techniques in select cases. However, this technique usually requires a posterior bony and mucosal septectomy. This posterior septectomy, although useful for adequate access and instrument triangulation, can potentially lead to increased crusting postoperatively. 41 Additionally, the posterior septectomy can compromise the surface area and extent of the PNSF. Previously, we described a mucosal-sparing option that preserved the integrity of the PNSFs by fully releasing two opposing flaps that are stored into the middle meati during the resection portion of the procedure. In this previous description, the PNSFs are completely released from the nasal septum. These three newly described mucosal-sparing posterior septectomy variations/refinements are useful variants of the traditional endoscopic transnasal transclival and Fig. 3. Thirty-degree endoscopic photograph demonstrating the access using the hybrid option with tucking of the left PNSF into the left middle meatus. LIT 5 left inferior turbinate; PNSF 5 pedicled nasoseptal flap. 2223

5 transodontoid approaches by allowing preservation of the mucosal integrity of the posterior nasal septum and rescuing a potential reconstructive option for later use. All three variations accomplish this goal without compromising visualization or surgical freedom. The first variation (option 1) involves bilateral PNSFs elevation with preservation of both the superior and inferolateral attachments of the flaps. This approach may be the most restrictive in terms of surgical maneuverability, but it should provide the easiest closure and is the least destructive to the normal sinonasal architecture. With limited but adequate resection of the posterior and lateral aspect of the flaps in the region of the choanal arch, along with sufficient lateral retraction of the PNSFs around the area of their sphenopalatine artery, significant improvement in visualization of the surgical target and surgical maneuverability can be obtained. The second variation (option 2) entails bilateral PNSF elevations with inferolateral release. In this technique, the PNSFs are left attached to the superior nasal septum. By rotating the flaps superiorly and tucking them into the middle meati, more lateral exposure of the CCJ can be achieved after the posterior septectomy due to a wider operative corridor. One important pearl in this technique is to make the inferior incisions laterally over the hard palate (extended under the inferior turbinates). An incision made directly at the junction of the nasal septum and the nasal floor may retract superiorly after closure and cause an inferior septal defect in this region. This is even more critical in cases when the surgical target is at the inferior one-third of the clivus or superior cervical spine. In these cases, the posterior nasal spine and vomeric crest typically need to be resected all the way down to the level of the nasal floor to allow adequate inferior exposure and surgical freedom. The absence of this ledge of bone (where the inferior edge of the flaps usually lay) makes it more difficult to prevent an inferior perforation if the PNSFs were not extended laterally enough. Another important point in this approach is the need to resect a sleeve of PNSF postero-laterally along the choanal arch to improve visualization and allow more lateral access. Lastly, in some cases, patients anatomy may make it difficult to sufficiently tuck the flaps into the middle meati. In that situation, the superior aspect of the surgical corridor may become restricted with limited surgical maneuverability and soiling of the endoscope with blood from the PNSFs. One remedy could be to release the flaps superiorly from the superior nasal septum and rotate and store them inside the sphenoid sinus (if the pathology does not involve this sinus and the floor of the sinus is not resected as part of the approach). Another option could be to perform a maxillary antrostomy for flap storage. The third variation (option 3), which is a hybrid of the two previous variations, can also provide adequate access. If surgical freedom is significantly restricted while performing the previously described technique, with preservation of both the superior and inferolateral attachments of the PNSFs (option 1), one has the option to move to this hybrid technique by releasing the flap inferolaterally on the restricted side. A decision could also be made to plan for this approach from the beginning of a case if a lesion is asymmetrically located. The advantage of this technique (option 3) is that it provides slightly better access than the more restrictive technique (option 1) but is less invasive than releasing both flaps inferolaterally (option 2). Therefore, the risk of postoperative septal perforation should be less than in option 2. If this hybrid technique is still found to be inadequate for the necessary exposure, proceeding to option 2 will only require inferolateral release of the PNSF that is still attached to the nasal floor. Based on the anatomic dissections performed and the authors clinical experience, we believe that these variations can be useful for almost all lesions of the CCJ. Lesions extending superiorly to the level of the tuberculum sellae and planum sphenoidale may require full release of the PNSFs for adequate exposure. These lesions often also necessitate a posterior ethmoidectomy for adequate visualization and surgical maneuverability. For lesions extending lateral to the vidian nerve course, adequate visualization and instrumentation can be facilitated by releasing the ipsilateral PNSF inferiorly. Based on these qualitative endoscopic cadaveric dissections, these endoscopic endonasal mucosal-sparing approaches to the CCJ represent useful alternatives to the standard endoscopic endonasal approach to the CCJ with posterior septectomy. These variations can be useful additions to the armamentarium of the endoscopic skull base surgeon, with benefits of sparing the posterior septal mucosa. These approaches have been used in our endoscopic skull base practice with successful result. CONCLUSION The three mucosal-sparing variations/refinements for the endoscopic endonasal posterior septectomy approach to the CCJ allowed adequate surgical access to the clivus, C1 arch, and odontoid process with sufficient maneuverability while preserving both PNSFs. 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