Abstract
Purpose
Using a transnasal, transfacial, anterior skull base approach, we have removed olfactory neuroblastomas (OFN) obviating the need for a frontal craniotomy. The objectives were to present our surgical approach in achieving clear margins, to assess patient survival, and to recommend eligibility criteria.
Materials and methods
A retrospective chart review was done to identify patients diagnosed with OFN who underwent this surgical approach. Thirteen patients were identified who underwent our pictorially described approach. Postoperative assessment of pathologic margins, patient survival, and limitations of surgical approach was determined.
Results
Of the 13 patients, 12 (92%) had clear postsurgical margins. One patient had residual intracranial disease due to coagulopathy preventing further resection. Twelve patients remain alive with 10 patients remaining disease-free (follow-up ranging from 11 to 64 months). Three patients presented with recurrent disease initially, with 2 having had subsequent repeat local and regional recurrences, respectively; one of whom died recently of the rerecurrent disease. One patient had a postoperative cerebrospinal fluid leak repaired via the original surgical approach.
Conclusions
Although craniofacial resection remains an accepted approach for surgical treatment of OFN, we have adopted a transnasal, transfacial approach eliminating the need for a frontal craniotomy. This approach allows for adequate exposure of the cribriform plate, dura, and anterior skull base. Our technique minimizes dural defects and prevents many craniotomy-associated complications, including frontal lobe retraction. Long-term follow-up is needed to compare survival using this approach; however, our results to date are quite promising.
1
Introduction
Olfactory neuroblastoma (OFN), or esthesioneuroblastoma, is an uncommon malignant tumor of the nasal cavity that was first described in 1924 . These tumors are thought to arise from the basal cells of the olfactory epithelium that can be located in the cribriform plate, superior and middle turbinates, and nasal septum . OFN can be locally aggressive, and given its location, skull base involvement can often occur .
With less than 1000 cases reported in the literature, the surgical approaches for managing this tumor have slowly evolved . Since the 1970s, the “gold standard” surgical approach for treating OFN has been craniofacial resection (CFR) combined with postoperative radiotherapy . However, significant morbidity and perioperative mortality associated with CFRs has led to less invasive approaches incorporating the endoscope in various ways . With newer techniques ranging from endoscopic-assisted CFRs to transnasal endoscopic resections, the long-term survival outcomes from near en bloc and/or piecemeal resections to avoid facial scars remains to be determined. Avoidance of a craniotomy yet achieving an oncologic en bloc resection with a minimally appreciable facial scar may be an alternative with improved survival and less complications.
Our surgical method for treatment of OFNs utilizes a transnasal, transfacial approach obviating the need for a craniotomy. Using a lateral rhinotomy approach along with anterior skull base resection via a 2-team approach with neurosurgery, this article will demonstrate this surgical technique in detail. In addition, the results will show the achievement of clear margins while minimizing complications as compared to the standard CFR approach. Patient survival status and examples of esthetic outcomes along eligibility criteria using this surgical approach will be described.
2
Methods
Institutional review board approval was obtained. A retrospective chart review was performed to identify patients who underwent a transnasal, transfacial anterior skull base resection of OFNs between January 2002 and December 2007 at the University of California, Los Angeles Medical Center. Patient records were evaluated for the following: demographic data, clinical presentation, perioperative and postoperative course, receiving chemotherapy and/or radiation therapy, complications, rates of recurrence and/or metastases, and survival. OFNs were staged according to the Dulguerov-Calcaterra staging system, which is based on preoperative computed tomography (CT) and/or magnetic resonance imaging (MRI) demonstrating the following: T1—tumor in the nasal cavity and sinuses, except sphenoid; T2—including sphenoid and/or cribriform plate; T3—plus orbit and/or extradural anterior skull base; and T4—including brain.
Since the beginning of the study period, no CFRs have been performed at our institution because all stages of OFN have been approached with this technique. All surgeries using this technique were performed by a single otolaryngologist (EA) and a single neurosurgeon (DFK) concurrently. Image guidance was used on every case (BrainLab, Westchester, IL). The operative technique begins with marking the lateral rhinotomy incision on the side of the lesion ( Fig. 1 ). A z-plasty type incision is used adjacent to the medial canthus. In addition, the incision is marked with an extension along the nasal sill and into the nasal floor. A medial maxillectomy is then performed, allowing entrance into and removal of the sinonasal components of the tumor ( Fig. 2 ). With neurosurgical assistance, an extracranial en bloc resection is made. Under microscopic visualization and using surgical navigation (BrainLab, Inc), tumor extending to the skull base is removed and the bone of the cribiform plate area is drilled. In patients with questionable or definitive intradural extension, the frontal fossa dura is opened. Tumor extending into the intradural space is removed along with a dural margin around the cribiform plate area. Margins are obtained from the sinonasal, extracranial, and intracranial components. If a dural defect and cerebrospinal fluid (CSF) leak is present after tumor removal, the defect is repaired in a multilayered fashion including placement of harvested abdominal fat graft, collagen matrix ( Helistat , Integra Corp, Plainsboro, NJ), and titanium mesh ( Fig. 3 ). In some instances, a septal mucosal graft is also used, as well as tissue sealant ( BioGlue CryoLife Inc, Atlanta GA). A lumbar drain for CSF diversion is placed in patients with the largest defects at the end of the procedure and left in place for 48 to 72 hours. An open dacrycystorhinostomy is performed, and the sinonasal cavity is filled with absorbable hemostatic matrix ( Surgiflo , Johnson & Johnson, Ethicon Corp Cincinnati, OH). The skin incision is closed in multiple layers.
2
Methods
Institutional review board approval was obtained. A retrospective chart review was performed to identify patients who underwent a transnasal, transfacial anterior skull base resection of OFNs between January 2002 and December 2007 at the University of California, Los Angeles Medical Center. Patient records were evaluated for the following: demographic data, clinical presentation, perioperative and postoperative course, receiving chemotherapy and/or radiation therapy, complications, rates of recurrence and/or metastases, and survival. OFNs were staged according to the Dulguerov-Calcaterra staging system, which is based on preoperative computed tomography (CT) and/or magnetic resonance imaging (MRI) demonstrating the following: T1—tumor in the nasal cavity and sinuses, except sphenoid; T2—including sphenoid and/or cribriform plate; T3—plus orbit and/or extradural anterior skull base; and T4—including brain.
Since the beginning of the study period, no CFRs have been performed at our institution because all stages of OFN have been approached with this technique. All surgeries using this technique were performed by a single otolaryngologist (EA) and a single neurosurgeon (DFK) concurrently. Image guidance was used on every case (BrainLab, Westchester, IL). The operative technique begins with marking the lateral rhinotomy incision on the side of the lesion ( Fig. 1 ). A z-plasty type incision is used adjacent to the medial canthus. In addition, the incision is marked with an extension along the nasal sill and into the nasal floor. A medial maxillectomy is then performed, allowing entrance into and removal of the sinonasal components of the tumor ( Fig. 2 ). With neurosurgical assistance, an extracranial en bloc resection is made. Under microscopic visualization and using surgical navigation (BrainLab, Inc), tumor extending to the skull base is removed and the bone of the cribiform plate area is drilled. In patients with questionable or definitive intradural extension, the frontal fossa dura is opened. Tumor extending into the intradural space is removed along with a dural margin around the cribiform plate area. Margins are obtained from the sinonasal, extracranial, and intracranial components. If a dural defect and cerebrospinal fluid (CSF) leak is present after tumor removal, the defect is repaired in a multilayered fashion including placement of harvested abdominal fat graft, collagen matrix ( Helistat , Integra Corp, Plainsboro, NJ), and titanium mesh ( Fig. 3 ). In some instances, a septal mucosal graft is also used, as well as tissue sealant ( BioGlue CryoLife Inc, Atlanta GA). A lumbar drain for CSF diversion is placed in patients with the largest defects at the end of the procedure and left in place for 48 to 72 hours. An open dacrycystorhinostomy is performed, and the sinonasal cavity is filled with absorbable hemostatic matrix ( Surgiflo , Johnson & Johnson, Ethicon Corp Cincinnati, OH). The skin incision is closed in multiple layers.
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