Double flap technique for reconstruction of anterior skull base defects after craniofacial tumor resection: technical note: Double flap technique for ASB reconstruction

Reconstruction of Large Anterior Skull Base Defects After Resection of Sinonasal Tumors With Intracranial Extension by Using Pedicled Double Flap Techniques

INTRODUCTION

The use of surgical resection for large anterior skull base (ASB) tumors and sinonasal malignancies with intracranial extension will result in a large skull base defect. Reconstruction of large ASB defects using traditional techniques is high risk and may lead to postoperative cerebral spinal fluid (CSF) leakage, meningitis, and an increase in mortality rate. The use of a pedicled double flap technique to reconstruct the ASB defect may decrease complications. This study presents the clinical outcomes of patients who underwent double flap reconstruction techniques after resection of their sinonasal malignancies with significant intracranial extension at Cho Ray hospital in Vietnam.

METHODS

The case series study was conducted at Cho Ray hospital from September 2010 to September 2020. All patients with large sinonasal malignancies that invaded intracranially underwent transnasal endoscopic surgery and subfrontal craniotomy. Reconstruction of large skull base defects (>2 cm) were followed up by using the pedicled double flaps technique. This study was performed in line with the principles of the Declaration of Helsinki. Approval of the study was granted by the Independent Ethics Committee of Cho Ray Hospital (Date: March 3, 2014/No: 11/BVCRHĐĐĐ).

RESULTS

During September 2010 to September 2020, there were 75 patients who underwent a modified multilayer, double flap reconstruction technique after the resection of their ASB tumor. Skull base defects were commonly seen along the horizontal plate of the ethmoid bone and the ethmoid roof (98.6%). Large skull base defects (>2 cm) accounted for 81.3% of cases. Overall, the risk of postoperative CSF leakage and meningitis after double flap repair was considerably low. Of all participants, only 1 experienced postoperative CSF leakage and 1 experienced postoperative meningitis. Despite the complications, these patients improved significantly and remained stable.

CONCLUSION

The use of double vascularized pedicled flaps may decrease the incidence of postoperative CSF leakage and meningitis. This technique is an effective method for the reconstruction of ASB tumors with large defects.

The Treatment Strategy for Skull Base Reconstruction for Anterior Cranial Fossa Intra- and Extracranial Tumors

ABSTRACT

Anterior cranial fossa intra- and extracranial tumors arise from the anterior cranial fossa and invade the orbit and nose. Anterior cranial fossa tumor resection and skull base reconstruction are challenging for neurosurgeons due to the complex anatomy, leakage of cerebrospinal fluid, and critical neurovasculature involvement. The authors report a case series of cranio-orbital communicating tumors and cranionasal-orbital communicating tumors. All patients underwent a modified Derome approach or transfrontal basal approach, and all tumor resections were satisfactory. Skull base reconstruction for small defects (<1.5 cm) can be performed with autogenous fascia, muscle, and fat. Large defects (≥1.5 cm) require autogenous fascia, muscle, and fat combined with osseous reconstruction (autogenous bone, titanium mesh, and polyetheretherketone). The techniques and treatments were successful, and only 1 patient experienced mild cerebrospinal fluid leak but no intracranial infection, pneumocrania or intracranial hemorrhage. Additionally, long-term follow-up demonstrated that the outcomes remain favorable. According to a literature review, this technique might be an alternative strategy for treating anterior cranial fossa intra- and extracranial tumors, and better skull base reconstruction can prevent many postoperative complications.

The Transorbital Pericranial Flap

OBJECTIVE

The objective of the present study was to describe and evaluate the feasibility, mobility, and surface area provided by the simple and extended transorbital pericranial flap (TOPF). Furthermore, we compared this novel technique with the current practice of pericranial flap harvesting and insetting techniques. We also studied the adequacy of the TOPF in the reconstruction of postoperative anterior cranial fossa (ACF) defects.

METHODS

The TOPF was performed bilaterally in 5 alcohol-preserved, latex-injected human cadaveric specimens. The TOPF was harvested in 2 stages: the orbitonasal stage and the cranial stage. For the orbitonasal stage, a transorbital superior eyelid approach was used. We have described 2 harvesting techniques for creating 2 distinct TOPF types (simple and extended) according to the main vascular pedicle. The superficial flap areas offered by the simple and extended TOPF and the traditional bicoronal pericranial flap were calculated and compared. The distances from the supratrochlear and supraorbital arteries to specified anatomical landmarks were also measured. Additionally, the ACF defect area of relevant surgical cases performed using endoscopic transcribriform approaches were measured on immediate postoperative computed tomography head scans using radiological imaging software.

RESULTS

The harvest of both the simple and the extended TOPFs was efficient. As expected, the areas offered by simple and extended TOPFs were smaller than that offered by the traditional bicoronal flap. However, the surface area offered by either the simple or extended TOPF provides sufficient coverage for most ACF defects. A high spatial distribution was observed between the vascular pedicles and their respective foramen or notch.

CONCLUSIONS

The TOPF represents a novel harvesting, tunneling, and insetting technique that offers a large, versatile, pedicled flap for coverage of most standard ACF defects after endoscopic surgery.

Efficacy of simultaneous pericranial and nasoseptal "double flap" reconstruction of anterior skull base defects after combined transbasal and endoscopic endonasal approaches

BACKGROUND

The "double flap" reconstruction technique, comprised of a simultaneous vascularized pedicled pericranial flap (PCF) and pedicled nasoseptal flap (NSF), can be used to repair anterior skull base defects after a combined cranionasal or transbasal-endoscopic endonasal approach (EEA) has been performed to remove malignant anterior skull base tumors. The use of two vascularized flaps may potentially decrease the incidence of post-radiation flap necrosis and postoperative cerebrospinal fluid (CSF) leaks after radiation therapy.

METHODS

We conducted a retrospective review of a prospective skull base database on patients who underwent the double flap reconstruction technique after a combined transbasal-EEA approach. Data collected for each patient included demographics, method of tumor resection and repair, complications, tumor recurrence, and follow-up.

RESULTS

Nine patients who underwent a combined transbasal-EEA approach for resection of anterior skull base tumors with significant intracranial extension followed by reconstruction of the cranial base using the double flap technique. Four were men and five were women, with a mean age of 49 years (range, 15-68 years). There was no postoperative CSF leakage detected or complications of infection, meningitis, mucocele, or tension pneumocephalus after a mean follow-up of 35.7 months (range, 4.5-98 months). Seven of the nine patients underwent adjuvant radiation without flap necrosis. Local tumor recurrence was not observed in any of the patients at last follow-up; however, one patient developed distant brain metastasis.

CONCLUSION

The simultaneous PCF and NSF double flap reconstruction is an effective technique in preventing postoperative CSF leakage and post-radiation necrosis when repairing anterior skull base defects after combined transbasal-EEA approaches. This technique may be useful in patients anticipated to undergo postoperative radiation therapy.

Sphenoid Mucocele: A Complication of Skull Base Reconstruction with Nasoseptal Flap-A Critical Review and Our Experience

The evolution of expanded endoscopic skull base surgery has enabled development of minimally invasive approaches for resection of large skull base tumors with the nasoseptal flap proving to be an indispensable tool in skull base reconstruction. We here present our experience of sphenoid mucocele development after skull base reconstruction with the nasoseptal flap along with a comprehensive review of the limited literature on the same. With the expanding scope of endoscopic skull base surgery, the nasoseptal flap is increasingly being used for reconstruction. Despite adherence to standard recommendations and use of meticulous technique during flap placement, the potential risk of mucocele formation under the flap should always be borne in mind. In our experience, displacement of the flap pedicle could lead to ostial obstruction and mucocele formation. Hence, in addition to meticulous technique, a close follow up of such patients via nasal endoscopy or imaging is important to further our knowledge and understanding of the long-term effects and complications of this flap.

Utilization of the Nasoseptal Flap for Repair of Cerebrospinal Fluid Leak after Endoscopic Endonasal Approach for Resection of Pituitary Tumors

Background

One of the most frequent complications after endoscopic endonasal approach (EEA) for resection of pituitary tumors is cerebrospinal fluid (CSF) leaks. With the introduction of the pedicled nasoseptal flap, the reconstruction of the skull base has improved significantly resulting in a decrease in the occurrence of persistent CSF leaks. We present our experience utilizing the pedicled nasoseptal flap technique after EEA for reconstruction of the skull base in cases where CSF leak was detected.

Methods

Data for patients undergoing EEA for pituitary tumors was retrospectively reviewed. These included demographic, clinical, operative, radiographic, and pathological information. Incidence of post-operative complications and CSF leaks were recorded. Descriptive statistical analysis was performed.

Results

Between 2008 and 2015, 67 patients and 69 hospital admissions with pituitary tumors underwent a nasoseptal flap to reconstruct a skull base defect at Johns Hopkins Hospital. The mean age at surgery was 54.5±14.2 years. Fifty-two percent of patients were male. Forty-six percent of patients were white, 33% African-American, and 12% belonged to other racial groups. There was an intraoperative CSF leak in 39% of patients. Seventy percent of patients with an intraoperative CSF leak had a nasoseptal flap reconstruction of the skull base. There were zero postoperative CSF leaks.

Conclusion

With the introduction of the pedicled nasoseptal flap for reconstruction of the skull base after EEA for resection of pituitary adenomas, the incidence of postoperative CSF leaks has decreased significantly. In this retrospective analysis, we demonstrate the effectiveness of the use of nasoseptal flap in repairing CSF leak after EEA.

Endoscopic endonasal double flap technique for reconstruction of large anterior skull base defects: technical note

Introduction

One of the main concerns in endoscopic endonasal approaches to the skull base has been the high incidence and morbidity associated with cerebrospinal fluid leaks. The introduction and routine use of vascularized flaps allowed a marked decrease in this complication followed by a great expansion in the indications and techniques used in endoscopic endonasal approaches, extending to defects from huge tumours and previously inaccessible areas of the skull base.

Objective

Describe the technique of performing endoscopic double flap multi-layered reconstruction of the anterior skull base without craniotomy.

Methods

Step by step description of the endoscopic double flap technique (nasoseptal and pericranial vascularized flaps and fascia lata free graft) as used and illustrated in two patients with an olfactory groove meningioma who underwent an endoscopic approach.

Results

Both patients achieved a gross total resection: subsequent reconstruction of the anterior skull base was performed with the nasoseptal and pericranial flaps onlay and a fascia lata free graft inlay. Both patients showed an excellent recovery, no signs of cerebrospinal fluid leak, meningitis, flap necrosis, chronic meningeal or sinonasal inflammation or cerebral herniation having developed.

Conclusion

This endoscopic double flap technique we have described is a viable, versatile and safe option for anterior skull base reconstructions, decreasing the incidence of complications in endoscopic endonasal approaches.

Utility of early postoperative imaging after combined endoscopic and open ventral skull base surgery

PURPOSE

Immediate postoperative imaging is frequently obtained after combined skull base surgery (SBS) with endoscopic endonasal and open transcranial approaches. The importance of early postoperative imaging for detecting complications in these patients is still debatable. In this study, we investigated the clinical utility of early postoperative imaging after combined SBS for determination of postoperative complications.

METHODS

A retrospective chart analysis of 21 cases of combined SBS between 2009 and 2015 was performed. Data on postoperative computed tomography (CT) and magnetic resonance imaging (MRI), and the hospital course were collected. We separated interpretations of postoperative imaging into two groups: (1) when using the radiologist's interpretation alone, and (2) when using the surgeon's knowledge of the case in conjunction with imaging.

RESULTS

Forty-two postoperative scans were obtained (21 CT, 21 MRI) within 48 hours of surgery. There was a significant statistical difference between imaging interpretation by surgeons and radiologists for CT interpretation only. For CT interpretation the true positive (TP), false positive (FP), true negative (TN), and false negative (FN) rates for radiologists (TP, 0/21; FP, 6/21; TN, 11/21; FN, 4/21) slightly deviated from surgeons' interpretation (TP, 1/21 [p = 0.9999]; FP, 0/21 [p = 0.0207]; TN, 17/21 [p = 0.1000]; FN, 3/21 [p = 1.000]). Rates for MRI interpretation by both groups were nearly identical, with no significant difference found. Overall, four patients experienced seven postoperative complications, which led to a complication rate of 19.0% (4/21). The patients exhibited clinical symptoms in all instances of postoperative complications that required further intervention.

CONCLUSION

The benefit of early postoperative imaging to detect complications after combined SBS was limited. In this cohort of patients, positive imaging findings' effects on patient management were dictated by the presence of supporting clinical symptoms.

Delayed Breakdown of an Onlay Pericranial Flap Following Endoscopic Craniofacial Resection

The pericranial flap is a well-vascularized, robust flap that is used to reconstruct anterior skull base defects following resection of skull base tumors. Failure of this flap is uncommon. However when it occurs, the consequences are potentially disastrous and it poses a challenge to further reconstruction. The authors report the first patient of onlay pericranial flap breakdown following endoscopic craniofacial resection. Possible contributing factors are identified and further management is discussed. With the endoscopic approach being increasingly utilized for craniofacial resection, it is imperative to be mindful of these factors to minimize the risks of onlay pericranial flap failure.

Relaxing Sphenoidal Slit Incision to Extend the Anterior and Posterior Reach of Pedicled Nasoseptal Flaps During Endoscopic Skull Base Reconstruction of Transcribriform Defects: Technical Note and Results in 20 Patients

BACKGROUND

Reconstruction of large anterior skull base (ASB) defects after an endoscopic endonasal transcribriform approach (EEA-TC) remains a challenge despite the advent of the vascularized pedicled nasoseptal flap (PNSF).

OBJECTIVE

We describe a relaxing PNSF slit incision that extends the anterior and posterior reach of the PNSF to maximize tensionless flap coverage of transcribriform ASB defects.

METHODS

A retrospective chart review was conducted on 20 consecutive patients who underwent endoscopic endonasal transcribriform approach and subsequent PNSF reconstruction with a relaxing slit incision. At the time of endoscopic ASB reconstruction, the PNSF is rotated into position so that the anterior margin of the flap is situated at the posterior table of the frontal sinus. A relaxing slit incision is made across the sphenoidal segment of the PNSF, which is the segment of flap that bridges across the sphenoid sinus once the flap is rotated into position. The anterior reach of the flap is increased to adequately cover the posterior table of the frontal sinus, and the redundant sphenoidal flap is rotated posteriorly to make contact to the bony planum sphenoidale.

RESULTS

No patients developed postoperative cerebrospinal fluid leaks (0%). The ASB repair was monitored via postoperative outpatient nasal endoscopy at various time points, which demonstrated excellent mucosalization of the ASB with a mean follow-up of 19.2 months (range: 4.1-36.2 months).

CONCLUSIONS

Our simple relaxing slit incision in the sphenoidal portion of the PNSF allows for maximal tensionless coverage of extensive transcribriform defects by increasing the anterior and posterior reach of the flap.

Management of Skull Base Defects After Surgical Resection of Sinonasal and Ventral Skull Base Malignancies

Over the past 2 decades, there has been a significant increase in the resection of larger and more complex ventral skull base malignancies. The resection of these lesions has resulted in the creation of larger and more difficult to repair skull base defects. There are many available options for ventral skull base reconstruction. Despite the variety of reconstructive options, the key objective is to eliminate any communication between the intracranial space and the sinonasal cavity. This article discusses some of the more common techniques currently used for repair of these skull base defects.

Combined Endoscopic and Open Approaches in the Management of Sinonasal and Ventral Skull Base Malignancies

Combined transcranial and endoscopic endonasal approaches remain useful in the treatment of ventral skull base malignancies. The extended bifrontal transbasal approach provides wide access to the anterior ventral skull base and paranasal sinuses without transfacial incisions. In more extensive lesions, the bifrontal transbasal approach can then be combined with an endoscopic endonasal approach (EEA) from below. This article reviews the indications, surgical technique, and operative nuances of combined transbasal and EEA (cranionasal) approaches for the surgical management of ventral skull base malignancies.

Contemporary Trends in the Management of Posttraumatic Cerebrospinal Fluid Leaks

The objective of this review is to provide an overview on the diagnosis and management of traumatic cerebrospinal fluid (CSF) leaks. This comprehensive review explores controversies associated with the management of CSF leaks as well as a review of the most contemporary literature. The scope of this article covers both traumatic CSF leaks of the middle and anterior cranial fossae.

Variations of mucosal-sparing septectomy for endonasal approach to the craniocervical junction

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.

LEVEL OF EVIDENCE

NA. Laryngoscope, 126:2220-2225, 2016.

Extensive traumatic anterior skull base fractures with cerebrospinal fluid leak: classification and repair techniques using combined vascularized tissue flaps

OBJECTIVE

This article introduces a classification scheme for extensive traumatic anterior skull base fracture to help stratify surgical treatment options. The authors describe their multilayer repair technique for cerebrospinal fluid (CSF) leak resulting from extensive anterior skull base fracture using a combination of laterally pediculated temporalis fascial-pericranial, nasoseptal-pericranial, and anterior pericranial flaps.

METHODS

Retrospective chart review identified patients treated surgically between January 2004 and May 2014 for anterior skull base fractures with CSF fistulas. All patients were treated with bifrontal craniotomy and received pedicled tissue flaps. Cases were classified according to the extent of fracture: Class I (frontal bone/sinus involvement only); Class II (extent of involvement to ethmoid cribriform plate); and Class III (extent of involvement to sphenoid bone/sinus). Surgical repair techniques were tailored to the types of fractures. Patients were assessed for CSF leak at follow-up. The Fisher exact test was applied to investigate whether the repair techniques were associated with persistent postoperative CSF leak.

RESULTS

Forty-three patients were identified in this series. Thirty-seven (86%) were male. The patients' mean age was 33 years (range 11-79 years). The mean overall length of follow-up was 14 months (range 5-45 months). Six fractures were classified as Class I, 8 as Class II, and 29 as Class III. The anterior pericranial flap alone was used in 33 patients (77%). Multiple flaps were used in 10 patients (3 salvage) (28%)--1 with Class II and 9 with Class III fractures. Five (17%) of the 30 patients with Class II or III fractures who received only a single anterior pericranial flap had persistent CSF leak (p < 0.31). No CSF leak was found in patients who received multiple flaps. Although postoperative CSF leak occurred only in high-grade fractures with single anterior flap repair, this finding was not significant.

CONCLUSIONS

Extensive anterior skull base fractures often require aggressive treatment to provide the greatest long-term functional and cosmetic benefits. Several vascularized tissue flaps can be used, either alone or in combination. Vascularized flaps are an ideal substrate for cranial base repair. Dual and triple flap techniques that combine the use of various anterior, lateral, and nasoseptal flaps allow for a comprehensive arsenal in multilayered skull base repair and salvage therapy for extensive and severe fractures.

Updates in reconstruction of skull base defects

PURPOSE OF REVIEW

Skull base surgery has undergone a fundamental transformation with the development and rapid adoption of endoscopic endonasal expanded approaches. Defects created from these newer approaches have necessitated an evolution of novel reconstructive techniques, which are reviewed here.

RECENT FINDINGS

New reconstructive techniques continue to be developed for repairing surgical defects from endoscopic endonasal skull base resections. Improvisations also allow well known flaps to be used in these approaches. Long term outcomes from repair using some of these techniques are now becoming available.

SUMMARY

Endoscopic resection of previously unapproachable skull base lesions has become possible with advancements in technology, as well as reconstructive methods. These newer techniques may offer improved outcomes and lower morbidity over conventional surgery.

A novel graft material for preventing cerebrospinal fluid leakage in skull base reconstruction: technical note of perifascial areolar tissue

Objectives Perifascial areolar tissue (PAT), a layer of loose connective tissue on the deep fascias with a rich vascular plexus, serves as a vital cover over defects with scarce vascularity. We report the usefulness of PAT as a nonvascularized alternative to flaps for reconstruction of dural defects in skull base surgery and transsphenoidal surgery while evaluating its effect on control of cerebrospinal fluid (CSF) leakage. Design A retrospective chart analysis was performed on patients who had undergone repair of a dural defect with PAT during skull base surgery or transsphenoidal surgery between December 2004 and October 2011. Results Twenty-one patients were included: 11 patients had received surgical treatment and/or irradiation. Fourteen of the 21 patients had pre- and/or intraoperative CSF leakage. Only one patient (4.8%) had postoperative CSF leakage requiring additional surgical repair. Ten patients underwent postoperative irradiation from 1 to 15 months after transplant of the PAT. None of the patients had postoperative CSF leakage after irradiation. Conclusion We successfully repaired dural defects using PAT in skull base surgery and transsphenoidal surgery, even in patients with a history of multiple operations and radiotherapy. PAT may serve as a valuable tool for skull base reconstruction.

Schwannomas of the sinonasal tract and anterior skull base: a systematic review of 94 cases

BACKGROUND

Schwannomas of the anterior skull base (ASB) and sinonasal tract are extremely rare. These lesions mimic other pathologies such as olfactory groove meningiomas, hemangiopericytomas, and esthesioneuroblastomas. Because of their low incidence, ASB and sinonasal tract schwannomas have not been well characterized. A systematic review of ASB and sinonasal tract schwannomas was conducted to further elucidate the presentation and surgical management of these lesions.

METHODS

A MEDLINE/PubMed search was performed, identifying 71 articles representing 94 cases of ASB and sinonasal schwannomas. Each case was analyzed for demographics, clinical presentation, anatomic location, radiographic features, and surgical treatment.

RESULTS

In 94 patients with ASB and sinonasal schwannomas, 44 (46.8%) were exclusively sinonasal, 30 cases (31.9%) were exclusively intracranial, 12 (12.8%) were primarily intracranial with extension into the paranasal sinuses, and 8 (8.5%) were primarily sinonasal with intracranial extension. Headaches and nasal obstruction were the most common presenting symptoms occurring in 30.9 and 29.8% of cases, respectively. Magnetic resonance imaging typically showed a hyperintense mass on T2-weighted imaging (70%) and hypointense (41%) on T1-weighted imaging. Most patients underwent surgical gross total resection via craniotomy, endoscopic endonasal approach, rhinotomy, or other sinonasal approaches. Recurrence occurred in three cases ranging from 4 months to 13 years. Postoperative complications included cerebral spinal fluid leakage, bacterial meningitis, epidural hematoma, and pneumocranium.

CONCLUSION

ASB and sinonasal schwannomas are rare lesions and should be considered in the differential diagnosis of ASB masses involving the cribriform plate with sinonasal extension. Gross total resection of these lesions should be considered the goal of operative management.

Structural pedicled mucochondral-osteal nasoseptal flap: a novel method for orbital floor reconstruction after sinonasal and skull base tumor resection

Unrepaired orbital floor defects after sinonasal and skull-base tumor resection can lead to herniation of orbital contents into the maxillary or ethmoidal sinuses, possibly resulting in infection and significant cosmetic and functional deficits. Orbital floor defects are usually repaired using prosthetic implants or autogenous material. Nasal septal cartilage has been used previously as a free graft for reconstruction. However, its reliance on local vascular supply can result in ischemia and necrosis in the postoperative period. The vascularized pedicled nasoseptal flap, consisting of mucoperichondrium and mucoperiosteum, is routinely used as an effective reconstruction method for endoscopic repair of cerebrospinal fluid leaks arising from skull base dural defects. However, this flap does not provide rigid structural reconstruction when used alone. We report a case of an orbital floor defect repaired using a pedicled mucochondral-osteal nasoseptal flap. This technique incorporates the structural component of the nasal septal cartilage and bone with the vascularized pedicled nasoseptal flap. This repair technique may be useful in patients requiring postoperative radiotherapy.

Assessment of mucocele formation after endoscopic nasoseptal flap reconstruction of skull base defects

Advances in endoscopic skull base (SB) surgery have led to the resection of increasingly larger cranial base lesions, resulting in large SB defects. These defects have initially led to increased postoperative cerebrospinal fluid (CSF) leaks. The development of the vascularized pedicled nasoseptal flap (PNSF) has successfully reduced postoperative CSF leaks. Mucocele formation, however, has been reported as a complication of this technique. In this study, we analyze the incidence of mucocele formation after repair of SB defects using a PNSF. A retrospective review was performed from December 2008 to December 2011 to identify patients who underwent PNSF reconstruction for large ventral SB defects. Demographic data, defect site, incidence of postoperative CSF leaks, and rate of mucocele formation were collected. Seventy patients undergoing PNSF repair of SB defects were identified. No postoperative mucocele formation was noted at an average radiological follow-up of 11.7 months (range, 3–36.9 months) and clinical follow-up of 13.8 months (range, 3–38.9 months), making the overall mucocele rate 0%. The postoperative CSF leak rate was 2.9%. Proper closure of SB defects is crucial to prevent CSF leaks. The PNSF is an efficient technique for these repairs. Although this flap may carry an inherent risk of mucocele formation when placed over mucosalized bone during repair, we found that meticulous and strategic removal of mucosa from the site of flap placement resulted in a 0% incidence of postoperative mucocele formation in our cohort.

Early harvesting of the vascularized pedicled nasoseptal flap during endoscopic skull base surgery

PURPOSE

The vascularized pedicled nasoseptal flap (PNSF) represents a successful option for reconstruction of large skull base defects after expanded endoscopic endonasal approaches (EEA). This vascularized flap can be harvested early or late in the operation depending on the anticipation of high-flow CSF leaks. Each harvesting technique (early vs. late) is associated with different advantages and disadvantages. In this study, we evaluate our experience with early harvesting of the PNSF for repair of large skull base defects after EEA.

METHODS

A retrospective review was performed at a tertiary care medical center on patients who underwent early PNSF harvesting during reconstruction of intraoperative high-flow CSF leaks after EEA between December 2008 and March 2012. Demographic data, repair materials, surgical approach, and incidence of PNSF usage were collected.

RESULTS

Eighty-seven patients meeting the inclusion criteria were identified. In 86 procedures (98.9%), the PNSF harvested at the beginning of the operation was used. In 1 case (1.1%), the PNSF was not used because a high-flow intraoperative CSF leak was not encountered. This patient had recurrence of intradural disease 8months later, and the previously elevated PNSF was subsequent used after tumor resection.

CONCLUSION

Based on our data, a high-flow CSF leak and need for a PNSF can be accurately anticipated in patients undergoing EEA for skull base lesions. Because of the advantages of early harvesting of the PNSF and the high preoperative predictive value of CSF leak anticipations, this technique represents a feasible harvesting practice for EEA surgeries.

Hyperostotic Esthesioneuroblastoma

Esthesioneuroblastomas are rare, soft-tissue tumors that can often extend from the sinonasal cavity into the intracranial and orbital space. Prognosis depends upon the histological grade and location/extent of the tumor. Treatment often consists of maximum surgical resection followed by adjuvant chemoradiation therapy. We present a case of a patient with esthesioneuroblastoma accompanied by an extensive osteoblastic reaction leading to significant hyperostosis along the skull base. His presenting symptoms included diplopia, and imaging revealed invasion of the orbital and intracranial spaces. Although a gross total resection of the soft tissue component of the tumor was achieved, a complete removal of the involved hyperostotic skull base could not be performed despite endoscopic endonasal and bifrontal craniotomy approaches in the same operative setting. Symptomatically, the patient improved and went on to receive chemoradiation therapy; he remains clinically and radiographically stable at 12 months. Investigation into the genetics and immunohistochemistry of this rare, hyperostotic variant of estheioneuroblastoma may provide details regarding its aggressive nature.