Anterior skull base surgery for malignant tumors: a multivariate analysis of 27 years of experience

INTRODUCTION: Few studies have examined prognostic factors that have an impact on outcomes in anterior skull base surgery by multivariate analysis. METHODS: We retrospectively examined our institution's skull base experience from 1973-2000. RESULTS: During this time, 166 patients underwent an anterior skull base resection for malignancy (median age, 53 years; range, 6-92 years). The 5-year relapse-free and disease-specific survival was 41% and 57% (median follow-up, 53 months). Multivariate analysis found that dural invasion, primary histologic diagnosis, and margin status had a significant impact on relapse-free and disease-specific survival. CONCLUSIONS: These data indicate that patients with anterior skull base malignancies are treated successfully with skull base surgery. Patients demonstrating adverse prognostic variables such as dural invasion, adverse histologic findings, and/or positive margins should be considered for the addition of adjuvant therapy or innovative therapies as they become available in the future.     

Anterior skull base surgery without prophylactic airway diversion procedures.

OBJECTIVE: Although anterior skull base surgery has become a relatively safe and effective procedure, postoperative complications remain a serious problem. One of the most devastating complications of anterior skull base procedures is tension pneumocephalus (TP). In order to prevent TP, authors have recommended the use of prophylactic airway diversion procedures, such as prolonged endotracheal intubation or prophylactic tracheostomy. However, these procedures may mask neurologic deterioration, delay treatment, and prolong rehabilitation. The purpose of this study was to determine the need for airway diversion procedures in anterior skull base surgery. STUDY DESIGN: Eighty-five patients underwent anterior skull base operations through the subcranial approach without prophylactic airway diversion. Sixty-four patients underwent resection of tumors, 12 patients underwent repair of cerebrospinal fluid leak, 6 patients underwent surgery due to anterior skull base fungal infections, and 3 patients underwent anterior skull base reconstruction procedures. RESULTS: The complication rate of TP was 1.2% (1/85). This complication rate is similar to that previously reported for operations performed with airway diversion procedures. CONCLUSION: Prophylactic airway diversion procedures are unnecessary in routine anterior skull base operations. Airway diversion should be indicated only when factors that might predispose the patient to risk of TP have been identified (ie, chronic cough or obstructive pulmonary diseases).     

Extended fronto-orbital approaches to the anterior cranial base: variations on a theme

Combined frontal, orbital and zygomatic osteotomies have expanded the skull base surgeon's repertoire of approaches to the anterior skull base. Techniques borrowed from craniofacial surgery provide for extensive exposure of the orbit and anterior fossa while minimizing brain retraction. This article emphasizes the variations on the theme of fronto-orbital craniotomy that allow this approach to be adapted to the precise location and extent of the lesion to be excised. Familiarity with these versatile techniques is an important part of the skull base surgeon's armamentarium.     

Extended Fronto-Orbital Approaches to the Anterior Cranial Base: Variations on a Theme

Combined frontal, orbital and zygomatic osteotomies have expanded the skull base surgeon's repertoire of approaches to the anterior skull base. Techniques borrowed from craniofacial surgery provide for extensive exposure of the orbit and anterior fossa while minimizing brain retraction. This article emphasizes the variations on the theme of fronto-orbital craniotomy that allow this approach to be adapted to the precise location and extent of the lesion to be excised. Familiarity with these versatile techniques is an important part of the skull base surgeon's armamentarium.     

A RETROSPECTIVE STUDY OF THE EXTERNAL VENTRICULAR DIVERSION OF CSF PERFORMED IN A LOCAL NEUROSURGICAL UNIT IN HK

Aims: This study is to present the application of stereotactic navigation guidance in anterior skull base surgery. The anterior skull base is remote from the surface structure of the facial skeleton and create a difficult access for tumour resection. The location of the internal carotid arteries which lie at the paranasopharyngeal space and other structures can be identified precisely with the use of stereotactic navigation guidance to allow safe and exact tumour dissection and clearance in and around the anterior skull base region. Method: Ten adult Chinese patients with recurrent nasopharyngeal carcinoma which affects the nasopharynx or sphenoid sinus were studied between July 1999 and September 2000. All the patients were operated under general anaesthesia with the aid of stereotactic navigation guidance for location of the internal carotid arteries intra‐operatively. Results: All the internal carotid arteries could be identified and located. The resection margins were all clear. There was no mortality or major morbidity. All patients recovery uneventfully and discharged home within 10 days and has got no recurrence on follow up ranging from 2 to 14 months. Conclusion: Stereotactic navigation guidance is an effective technique in locating the internal carotid artery to allow safe tumour dissection in the anterior skull base region.     

Percutaneous computer tomography-guided technique to close postsurgical cerebrospinal fluid fistulas of the frontal sinus

BACKGROUND: The occurrence of cerebrospinal fluid fistulas of the frontal sinus after anterior skull base surgery is not rare. The extracerebral techniques to repair cerebrospinal fluid fistulas are often used, especially because they avoid open-air surgical operations. METHODS: A percutaneous CT-guided technique to close postsurgical cerebrospinal fluid fistulas of the frontal sinus in three patients after anterior skull base surgery is presented in this report. Ten millimeters of human fibrin glue was injected into the frontal sinus through one of the burr holes of the bone flap by an 18-gauge spinal needle. RESULTS: After an average follow-up period of 2.8 years, all three patients are in excellent general and neurological conditions and have not shown any further signs of rhinoliquorrhea. CONCLUSIONS: The presented percutaneous CT-guided technique can be considered a valid and harmless solution to closer small or moderate cerebrospinal fluid fistula that occurred after anterior skull base surgery.     

Template-based registration for image-guided skull base surgery

OBJECTIVES: To evaluate whether patient-to-image registration with the use of a maxillary template is sufficiently accurate for image guided skull base surgery. STUDY DESIGN AND SETTING: In an experimental phantom study, pair-point registration of a skull phantom to its CT image data was performed with 243 different configurations of a maxillary template with markers. Then artificial skull mounted target markers were located with an infrared tracking device as used in navigation systems. RESULTS: The average target registration error was 1.57 mm in the anterior skull base (95% confidence interval, 1.53 to 1.61 mm), but 3.31 mm in the lateral skull base (95% confidence interval, 3.26 to 3.37 mm). CONCLUSIONS: Fiducial marker registration based on a maxillary template is sufficiently accurate for image-guided surgery in the anterior skull base, but not for the lateral skull base. SIGNIFICANCE: Template-based registration is an accurate yet noninvasive registration method for frontal skull base surgery.     

Reconstruction of the median anterior skull base with an intracranial free radial forearm flap after recurrent resection of tumour

Abstract

We report a case of a median anterior skull base defect that was reconstructed with a free radial forearm flap. The flap was used intracranially, whereas the vascular anastomosis was made extracranially, with the pedicle running through a burr hole in the skull. This technique was succesful in sealing the skull base from the nasal cavity and preventing leakage of cerebrospinal fluid, infection, or herniation of brain tissue. We report the reconstructive procedure, an overview of other options, and the reasons for the decisions in this case.     

Contrecoup fractures of the anterior cranial fossae as a consequence of blunt force caused by a fall

Summary Contrecoup fractures of the base of the skull are regarded as rare in the clinical literature.In our material (n=171 falls on the same level and on or from stairs), the overall frequency of contrecoup fractures of the anterior cranial fossa in fatal cranio-cerebral trauma due to falls was 12%, as compared to 24% with occipital point of impact of the head.The relationships between the impact site on the head, form of fracture at the point of impact with involvement of the skull cap and/or the base of the skull, coup and contrecoup injuries of the brain, localization of contrecoup fractures in the anterior cranial fossa and the occurrence of monocle and spectacle haematomas display a major variability.Fractures occur in the form of simple fractures and as impression fractures (fracture fragments or fracture boundaries displaced to the inside).Clinical diagnosis is difficult because of the concealed position of the anterior skull base.Contrecoup fractures become of forensic medical significance when symptoms of a frontobasal injury occur for the first time after trauma which has occured some time in the past and when the question arises as to the causal connection with the original trauma.In investigation of living persons, it may be difficult to decide whether haemorrhages in the region of the orbit and its vicinity result from a direct blunt force or derive from fractures of the base of the skull, especially contrecoup fractures.     

Extended pericranial flap and bone graft reconstruction in anterior skull base surgery.

OBJECTIVES: The objectives of this study was to establish a rationale for repairing large anterior skull base defects with an extended pericranial flap and split calvarial bone graft; to define large anterior skull base defects as those spanning the anterior cranial measuring at least 3.0 x 4.0 cm; and to describe the surgical technique and compare it with alternative strategies.Study design Thirty-four patients underwent anterior craniofacial resection of anterior skull-based tumors of varying histology with reconstruction using an extended pericranial flap and split calvarial bone graft. RESULTS: The survival of the pericranial flap and bone graft was maintained in 33 of 34 patients. There was 1 episode of postoperative cerebrospinal fluid leak, 1 episode of osteomyelitis of the bone graft and an epidural abscess, and 1 episode of asymptomatic pneumocephalus. CONCLUSION: Split calvarial bone graft with an extended pericranial flap is an effective technique for reconstructing large anterior skull base defects.     

Reconstruction of the Anterior Skull Base After Craniofacial Resection

Significant controversy continues as to how best to reconstruct anterior skull base defects after craniofacial resection with a view to minimizing the postoperative morbidity. Techniques varying from simple skin grafts to local and pedicled flaps, as well as bone harvested from a variety of sources have all been proposed. Careful review of the literature combined with personal experience with 34 anterior skull base defects following tumor surgery are presented in an attempt to develop a decision-making process to determine the ideal reconstructive technique for various situations.     

Reconstruction of the anterior skull base after craniofacial resection

Significant controversy continues as to how best to reconstruct anterior skull base defects after craniofacial resection with a view to minimizing the postoperative morbidity. Techniques varying from simple skin grafts to local and pedicled flaps, as well as bone harvested from a variety of sources have all been proposed. Careful review of the literature combined with personal experience with 34 anterior skull base defects following tumor surgery are presented in an attempt to develop a decision-making process to determine the ideal reconstructive technique for various situations.     

Craniofacial resection for anterior skull base tumours

Summary This study presents a series of 10 patients with anterior skull base tumours, treated by a team of neurosurgeons and head- and neck surgeons. The series included 7 malignant tumours of the nose and paranasal sinuses and 1 retinoblastoma, all with intracranial extension through the lamina cribrosa. There were also 2 patients with an anterior base meningioma, growing into the ethmoid sinus and the nasal cavity.8 tumours were resected by a combined bifrontal craniotomy and uni- or bilateral rhinotomy. In 2 cases a bifrontal craniotomy alone without facial incision sufficed. The skull base was closed with a pediculated pericranial flap and a split-thickness free skin graft underneath.There were no postoperative problems of wound infection, CSF-leakage or meningitis. Recurrent tumour growth or systemic metastasis occurred in 5 out of 7 patients with malignant tumours, 6 months to 2 years postoperatively.The related literature and especially questions of operative indications and technique, including different possibilities of closure and reconstruction of the skull base, are discussed.     

Modified Subtotal Lothrop Procedure for Extended Frontal Sinus and Anterior Skull Base Access: A Cadaveric Feasibility Study with Clinical Correlates

Objective The endoscopic modified Lothrop procedure (EMLP) is an established approach for recalcitrant frontal sinus disease and anterior skull base exposure. However, in select cases, this technique may involve unnecessary resection of sinonasal structures. In this study, we propose a modification of the EMLP, termed the modified subtotal-Lothrop procedure (MSLP), to access the anterior skull base and complex frontal sinus disease for which access to the bilateral frontal sinus posterior table is required.Methods A cadaveric dissection with photo documentation was performed at an academic medical center on four cadaver heads using standard endoscopic techniques to demonstrate the MSLP and its feasibility.Results The endoscopic MSLP allowed ample access for instrumentation in each of the dissections using a 30- or 70-degree endoscope. Adequate bilateral access to the posterior table of the frontal sinus was gained in all cases without the need for dissection of the contralateral frontal sinus recess (FSR).Conclusion The MSLP appears to be a feasible technique for exposure of the anterior skull base and accessing complex frontal sinus pathology. This modification provides similar anterior skull base exposure and surgical maneuverability as the EMLP while limiting surgical dissection to one FSR, thereby preserving as much of the natural mucociliary drainage pathways as possible.     

A case of multiple primary tumors of the anterior skull base.

We report a case of synchronous olfactory bulb meningioma and undifferentiated carcinoma of the nose and paranasal sinuses that involved and destroyed the anterior skull base and mimicked intracranial invasion by a carcinoma. The heterogeneity of tissue types in the skull base gives rise to a diverse variety of benign and malignant neoplasms which have totally different prognoses. Synchronous development of benign and malignant primary tumors both originating from and involving the skull base at the same location is very rare and may cause confusion for both the skull base surgeon and neuroradiologist.     

Pericranial flap for closure of paramedian anterior skull base defects

OBJECTIVE: We sought to examine the position of a pericranial flap reconstruction of anterior skull base defects with respect to the original floor of the anterior cranial fossa. STUDY DESIGN: A retrospective chart and radiology review of 17 patients (1993-2001) with pericranial flap reconstruction for anterior skull base defects and 17 controls was performed. RESULTS: At 6 or more months after surgery, the new positions of the pericranial flaps ranged from 5 mm above to 11.3 mm below the positions of the original cribriform plates. There were no complications related to the pericranial flaps such as hemorrhage, flap loss, or brain herniation except for 2 (11.8%) cerebrospinal fluid leaks, 1 of which required operative correction. CONCLUSION: Pericranial flap reconstruction is a reliable method with low morbidity for closure of the most common skull base defect from the craniofacial resection that entails removal-unilateral or bilateral-of the fovea ethmoidalis, cribriform plate, and/or superior septum. This flap creates a watertight seal between the extradural space and the nasal cavity, prevents clinically significant brain herniation, and is associated with a low rate of cerebrospinal fluid leakage even without postoperative lumbar subarachnoid drainage of the cerebrospinal fluid.     

Overlapping free bone graft with galea-pericranium in reconstruction of the anterior skull base to prevent CSF leak and sequestrum formation

Summary Background. Reconstruction of the skull base after resection of a tumour is important to prevent postoperative complications such as infectionsand cerebrospinal fluid (CSF) leakage. Several reconstructive methods of the anterior skull base have been reported but, their long-term results are not clear. Methods. We describe a technique used after removal of an olfactory neuroblastoma with infiltration of the skull base. The reconstructed dura was covered with a galeal patch, a replicated galeal-pericranial flap, a graft from the inner table of skull, and a vascularised galeal-pericranial flap placed on the skull base defect. All layers were fixed with fibrin glue. Conclusion. Three dimensional computed tomography (3D-CT) at bone window settings demonstrated the bone graft covered the bone defect and was not absorbed and after 11 years there have been no signs of tumour regrowth or complications.     

Combined Transcranial-endonasal Reconstructive Surgery for Cerebrospinal Fluid Leakage Resulting from Traumatic Anterior Skull Base Fractures Involving the Parasellar Region

Extensive traumatic anterior skull base fractures from the frontal sinus to the parasellar region are frequently accompanied by multiple dural defects that cause persistent cerebrospinal fluid (CSF) leakage. Conventional transcranial reconstruction using a frontal periosteal flap is frequently insufficient, and parasellar dural defects are often deep, complex, and difficult to identify. In this report, we describe a combined transcranial–endonasal reconstructive technique and report our experience. Simultaneous combined transcranial and endoscopic surgery was performed in three patients with CSF leakage resulting from traumatic anterior skull base fractures. Dural defects were thoroughly identified from the transcranial and endonasal surgical fields, and covered using a multilayer sealing technique. The anterior regions of the anterior skull base were reconstructed using a free fascial flap and frontal periosteal flap; posterior and parasellar regions were reconstructed using a fat graft, vascularized nasoseptal flap, and endonasal balloon. Suturing the transcranial grafts to the parasellar dura mater was performed collaboratively by the transcranial and endonasal surgeons. In our cases, complete cessation of CSF leakage was achieved without perioperative lumbar drainage in all patients. Mean time to postoperative ambulation was 7 days (range, 3–11). No surgical complications occurred. Simultaneous transcranial and endonasal procedures were helpful to detect all sites of CSF leakage and secure reconstructive grafts. The combined transcranial and endonasal reconstructive technique achieved secure skull base reconstruction without recurrence of CSF leakage, and allowed early postoperative ambulation. This technique can be a reliable surgical option to repair CSF leakage resulting from extensive anterior skull base fractures.     

The Transfrontal Approach Using Nasal Endoscopy to Treat Anterior Skull Base Carcinomas

We used a simple subcranial procedure that employed nasal endoscopy to resect two anterior skull base tumors. The solid geometry of the deep frontal sinus must be known to determine the appropriateness of this technique. Since 1999 two patients underwent this technique and have exhibited no signs of local or distant disease for 36 months and 32 months, respectively. This approach minimizes visible scarring, provides a wide exposure of the roof of the anterior ethmoid, and reduces the risks of excessive bleeding and neurogenic complications. The patients recovered rapidly so the treatment was cost-effective and the patients achieved an early return to work. We conclude that the transfrontal approach for anterior skull base tumors can be simple and effective. Further studies of this minimally invasive maneuver for high-risk patients are warranted.     

A modified frontal–nasal–orbital approach to midline lesions of the anterior cranial fossa and skull base: technical note with case illustrations

The frontal–nasal–orbital craniotomy has been utilized for craniofacial abnormalities and resection of tumors involving the anterior skull base. We describe modifications of this technique to approach extra-axial and intradural midline lesions of the anterior fossa with or without involvement of the skull base. A craniotomy was planned with an endoscope and image guidance. A modified frontal–nasal–orbital craniotomy encompassing the entire frontal sinus complex was performed in conjunction with osteotomies incorporating the bilateral superior orbital ridges and nasal septum. Removal of the posterior wall of the frontal sinus was completed if necessary. Dural repair and final reconstruction are detailed. Our initial experience using this approach in five patients harboring lesions of the anterior skull base resulted in adequate exposure of the targeted pathology. There were no complications of the procedure. Cosmetic results were acceptable. We present a detailed account of this procedure via photographs and a video. The frontal–nasal–orbital craniotomy provides access to the floor of the anterior fossa while avoiding excessive brain retraction associated with facial incisions. In addition, this approach is associated with a lower incidence of complications, such as CSF leak, brain retraction edema, or infection. The frontal–nasal–orbital craniotomy is a useful technique for midline lesions of the anterior skull base, and it should be in the armamentarium of neurological surgeons.