Transbasal Approach Research Articles

The radical transbasal approach for resection of anterior and midline skull base lesions

Craniofacial surgery can be performed to treat midline and anterior skull base lesions by creating a bicoronal scalp incision without the need for an additional transfacial procedure. Originally described as the transbasal approach, several modifications for further exposure of the skull base have been described. The authors present data on the application and outcomes of a modified transbasal approach. The radical transbasal approach consists of a bifrontal craniotomy and a frontoorbitonasal osteotomy. Between 1992 and 2002, 41 patients (28 male and 13 female patients with a mean age of 38.3 years [range 7-77 years]) underwent 44 radical transbasal procedures. Twenty-three malignant and 18 benign lesions involving the midline skull base were treated. These cases were reviewed retrospectively. Gross-total resection of 30 lesions was achieved. Seven lesions were resected subtotally and six partially; one lesion was debulked. Complications occurred in 26 (59.1%) of the 44 operations and mostly consisted of cerebrospinal fluid leakage. The surgery-related mortality rate was 6.8% (three patients). Based on their pre- and postoperative Karnofsky Performance Scale scores, 86.4% of patients improved or remained the same. The radical transbasal approach increases the midline craniofacial corridor by allowing the globes to be safely retracted laterally. It also enhances exposure of the maxillary sinus from above. The morbidity and mortality rates associated with this procedure are high but consistent with the known rates for craniofacial surgery. This approach is best suited for the treatment of anterior skull base tumors that extend into the nasal cavity, orbit, ethmoid sinus, nasopharynx, and upper clivus. The approach may allow resection of tumors involving the maxillary sinus area without the need for an additional transfacial approach.

Preserving Olfactory Function in Anterior Craniofacial Surgery through Cribriform Plate Osteotomy Applied in Selected Patients

Olfaction is often sacrificed to gain access to the cranial base in anterior craniofacial surgery. We describe the long-term results of olfactory function in patients who underwent anterior craniofacial surgery and a cribriform plate osteotomy to preserve olfaction. Between 1992 and 2004, 28 patients underwent 29 cribriform plate osteotomies in an attempt to preserve olfaction during anterior craniofacial surgery performed through modified extended transbasal approaches. Patients' charts and office notes were reviewed retrospectively. Formal olfactory testing was available in 5 patients, but most data were based on patients' subjective reports of olfaction. Olfactory preservation was defined by the subjective ability to detect fumes such as coffee, chocolate, roses, and orange juice regardless of the intensity of the sensation. Follow-up was based on phone calls to patients. Four patients were lost to follow-up and excluded. Therefore, follow-up was available in 24 patients after 25 procedures. On the basis of patients' subjective reports, olfaction was spared in 22 patients after 23 procedures (92%) and was confirmed objectively in the five patients formally tested. After surgery, only two patients were anosmic. Olfaction can be preserved in selected patients undergoing anterior craniofacial surgery. At least 1 cm of nasal mucosa should remain attached to the cribriform plate, which can be achieved by including the nasal bone in the osteotomy of the orbital bar. A medial orbital canthopexy is therefore necessary after these procedures.

Frontal skull base surgery combined with endonasal endoscopic sinus surgery

Background Postoperative infection remains a serious complication after radical resection of anterior skull base lesions because intracranial, nasal, and paranasal cavities are opened during surgery. To prevent complications from postoperative infection, we combined endonasal endoscopic sinus surgery (ESS) with the frontal transbasal approach in patients with skull base lesions. Methods Patients (n = 16) with anterior skull base lesions extending to the paranasal or nasal cavity underwent surgical resection via the frontal transbasal approach. After removal of the lesion via the transcranial approach, enlargement of the ostium or sinusotomy was performed bilaterally using our endonasal ESS procedure. The main purpose of ESS is the establishment of a wide drainage route to avoid dead space and postoperative infection. Furthermore, we confirmed the absence of residual lesion and leakage of cerebrospinal fluid (CSF), endoscopically. Results The frontal transbasal approach combined with endonasal ESS was performed in 16 patients with frontal skull base lesions. There were 8 malignant tumors, 6 benign tumors, and 2 mucoceles. Although 11 patients had preoperative active paranasal sinusitis, most frequently at the ethmoid sinus, none experienced postoperative infection. There was no complication related to ESS procedure. Furthermore, leakage of CSF and extracranial residual tumor were not found. Conclusion Endonasal ESS after frontal skull base surgery is a highly useful technique for preventing postoperative infection, especially for the cases with large skull base tumors extending into other regions involving the paranasal sinuses or nasal cavity and with active paranasal sinusitis.

Commentary

Background: Postoperative infection remains a serious complication after radical resection of anterior skull base lesions because intracranial, nasal, and paranasal cavities are opened during surgery. To prevent complications from postoperative infection, we combined endonasal endoscopic sinus surgery (ESS) with the frontal transbasal approach in patients with skull base lesions. Methods: Patients (n = 16) with anterior skull base lesions extending to the paranasal or nasal cavity underwent surgical resection via the frontal transbasal approach. After removal of the lesion via the transcranial approach, enlargement of the ostium or sinusotomy was performed bilaterally using our endonasal ESS procedure. The main purpose of ESS is the establishment of a wide drainage route to avoid dead space and postoperative infection. Furthermore, we confirmed the absence of residual lesion and leakage of cerebrospinal fluid (CSF), endoscopically. Results: The frontal transbasal approach combined with endonasal ESS was performed in 16 patients with frontal skull base lesions. There were 8 malignant tumors, 6 benign tumors, and 2 mucoceles. Although 11 patients had preoperative active paranasal sinusitis, most frequently at the ethmoid sinus, none experienced postoperative infection. There was no complication related to ESS procedure. Furthermore, leakage of CSF and extracranial residual tumor were not found. Conclusion: Endonasal ESS after frontal skull base surgery is a highly useful technique for preventing postoperative infection, especially for the cases with large skull base tumors extending into other regions involving the paranasal sinuses or nasal cavity and with active paranasal sinusitis.

Advances in surgical management of malignancies of the cranial base: the extended transbasal approach

The extended transbasal approach combines a bifrontal craniotomy with an orbital nasal and potentially a sphenoethmoidal osteotomy to provide excellent access to malignancies of the anterior, middle and posterior skull base. The approach enables the en bloc resection of tumors within the frontal lobes, orbits, paranasal sinuses and sphenoclival corridors without brain retraction and may obviate the need for transfacial access. We present our 7-year experience during which 29 patients underwent surgery with the extended transbasal exposure. In 25 patients the extended transbasal approach was used alone; in the remaining four it was combined with additional approaches. With exception of two patients, all lesions were removed en bloc. Reconstruction was accomplished with the use of pericranium and in some instances a temporalis muscle pedicle or a gracilis microvascular free flap. There were no mortalities associated with this approach. Seven patients experienced infections, four patients experienced cerebral spinal fluid (CSF) leakage, two patients who had received adjuvant radiation experienced scalp necrosis, three patients experienced pneumocephalus, and 29 patients experienced cranial neuropathies, the majority of which were loss of olfaction. The average follow-up for our patients was 34 months with a range of 2--62 months.

Subfrontal transbasal approach and technique for resection of craniopharyngioma

A multimodality approach to craniopharyngioma, including minimally invasive stereotactic techniques, microsurgery, conventional radiotherapy, and radiosurgery has been recommended to tackle craniopharyngioma aggressively while minimizing harm to the patient. With all approaches, there are varying levels of risk for endocrinological morbidity, vascular complications, neuropsychological and behavioral disorders, neurocognitive disorders, and learning disabilities. Although many treatment options are available, total tumor resection remains the most commonly performed procedure for treatment of craniopharyngioma, and it is still believed to give the patient the greatest chance of having an independent and productive life with low risk of recurrences. The authors prefer the subfrontal transbasal approach for resection of these tumors, and they describe this approach and illustrate it with the accompanying figures.

Navigation as a tool to visualize bone-covered hidden structures in transfrontal approaches

A retrospective analysis of 10 patients was performed to evaluate navigation systems in extranasal frontal skull base surgery. When performing a craniotomy following a bicoronal skin incision, the surgeon has to calculate the extent of the frontal sinus to avoid unnecessary damage to the dura or mucoceles later. Due to surgical morbidity including compression of the frontal lobe, many skull base surgeons have refused to use such an approach. Malformation or bone-destruction complicates the identification of the borders and increases the risk of side-effects. Navigation systems can be an alternative for calculating the frontal sinus outlines during surgery. In the authors' surgical procedure two different navigation systems were used. Conventional surgery using the transfrontal, transbasal or subcranial approach consisting of trepanation and craniotomy were performed, while the navigated surgical procedure was evaluated. The analysis showed that computer-assisted surgery (CAS) is applicable to extranasal frontal skull base surgery. In comparison to X-ray beam-controlled craniotomy, CAS is beneficial as it constitutes a noninvasive instrument of quality management. Furthermore, the analysis indicated that under the guidance of a navigation system a precise pre-surgical simulation is available in order to perform an optimal craniotomy and reconstruction of the frontal skull base.

Transbasal approaches: surgical details, pitfalls and avoidances.

Lesions involving the anterior skull base and sphenoclival region are difficult surgical problems. This paper presents surgical details, pitfalls, avoidances and our experiences in the surgical treatment of lesions of the anterior skull base using neuronavigation. Between 1999 and 2003, 33 patients with pathology of the anterior skull base were operated on via the traditional transbasal and the extended transbasal approach. A passive-marker-based neuronavigation system has been used for intraoperative image guidance since April 2000. The patients consisted of 11 men and 22 women. Their ages ranged from 3 to 76 years, with a mean of 41 years. The lesions for which the approach was used included 9 cerebrospinal fluid (CSF) fistulae and 24 neoplastic lesions including meningioma (16 cases), metastasis (3 cases), chordoma (3 cases), plasmacytoma (1 case), and osteoma (1 case). Gross total removal of the tumors was accomplished in 22 out of 24 patients with tumor (91.6%). Postoperative complications include CSF leakage (2 cases), infection (2 cases) and transient impaired vision (1 case). One patient (3%) died postoperatively from hypothalamic dysfunction after removal of a benign tumor extending to the anterior third ventricle. Despite the incidence of postoperative infection and the high rate of CSF leakage and death, it is possible to obtain long-term survival for patients with tumors previously considered challenging and difficult surgical problems.

Zones of Approach for Craniofacial Resection: Minimizing Facial Incisions for Resection of Anterior Cranial Base and Paranasal Sinus Tumors

Anterior cranial base tumors are surgically resected with combined craniofacial approaches that frequently involve disfiguring facial incisions and facial osteotomies. The authors outline three operative zones of the anterior cranial base and paranasal sinuses in which tumors can be resected with three standard surgical approaches that minimize transfacial incisions and extensive facial osteotomies. The zones were defined by performing dissections on 10 cadaveric heads and by evaluating radiographic images of patients with anterior cranial base tumors. The three approaches performed on each cadaver were transbasal, transmaxillary, and extended transsphenoidal. Three zones of approach were defined for accessing tumors of the anterior cranial base, nasal cavity, and paranasal sinuses. Zone 1 is exposed by the transbasal approach, which is limited anteriorly by the supraorbital rim, posteriorly by the optic chiasm and clivus, inferiorly by the palate, and laterally by the medial orbital walls. This approach allows access to the entire anterior cranial base, nasal cavity, and the majority of maxillary sinuses. The limitation imposed by the orbits results in a blind spot in the superolateral extent of the maxillary sinus. Zone 2 is exposed by a sublabial maxillotomy approach and accesses the entire maxillary sinus, including the superolateral blind spot and the ipsilateral anterior cavernous sinus. However, access to the anterior cranial base is limited. Zone 3 is exposed by the transsphenoidal approach. This approach accesses the midline structures but is limited by the lateral nasal walls and intracavernous carotid arteries. An extended transsphenoidal approach allows further exposure to the anterior cranial base, clivus, or cavernous sinuses. The use of the endoscope facilitates tumor resection in the nasal cavity and paranasal sinuses. The operative zones outlined offer minimally invasive craniofacial approaches to accessing lesions of the anterior cranial base and paranasal sinuses, obviating facial incisions and facial osteotomies. Case illustrations demonstrating the approach selection paradigm are presented.

Visual function following neurosurgical optic nerve decompression for compressive optic neuropathy.

To assess the course of visual function after neurosurgical decompression of the optic nerve during resection of intracranial tumours. To obtain information that may be used to counsel patients. A retrospective review of the acuity and visual fields of 27 patients undergoing neurosurgical decompression of 36 optic nerves in a regional neurosurgical centre. Two groups were considered, those undergoing craniotomy for sphenoid wing meningioma en plaque, and those undergoing an extended transbasal approach to intracranial tumours. At the last follow-up (1-97 months), improvement in acuity was seen in 47% of eyes with decompressed nerves. One-third of these showed late improvement, and two-thirds showed immediate improvement. In total, 20% of eyes had worse acuity at the last follow-up compared with preoperative values, just under one-third of these showed late deterioration, and the remainder showed immediate deterioration. In total, 33% of eyes achieved acuities equal to those recorded preoperatively, 6% improving to this level postoperatively. The majority of eyes in this study maintained or improved acuity after decompression. A proportion of eyes continue to improve after surgery, and a proportion deteriorate. There is no relation between duration of preoperative symptoms or the level of preoperative acuity and the change in acuity achieved.

Cementifying fibroma in the ethmoidal sinus extending to the anterior cranial base in an 11-year-old girl: a case report

A case of an 11-year-old female with cementifying fibroma in the ethmoidal sinus extending to the anterior cranial base was presented. She complained of slowly progressive nasal obstruction and anosmia. Magnetic resonance imaging (MRI) revealed a tumor in both ethmoidal and sphenoidal sinuses and nasal cavity. Although a tumor reduction surgery was attempted through a transnasal approach, tumor size increased gradually and right exophthalmos subsequently appeared. The pathological diagnosis was cementifying fibroma of the nose. Total tumor removal was consequently accomplished through the intracranial anterior transbasal approach. The surgical approach should be selected according to the site and expansion of the lesion in individual patients.

The Transbasal Approach and its Variations

The Transbasal Approach and its Variations

Extended transbasal approach with preservation of olfaction: ananatomical study

Many craniofacial approaches to the sphenoethmoidal region, anterior fossa, and central skull base compartment have been described, a number of which involve the mobilization of the frontonasoorbital complex en bloc. Spetzler's modification incorporates osteotomies around the cribriform plate, to preserve olfaction. In this morphological study of three cadavers, photographs were used to show the technique and define its anatomical boundaries and limitations. The study illustrates access to a number of anatomical regions, particularly the exposure of the medial orbit, the cavernous sinus, the clivus, and the vertebrobasilar complex.

Infrasellar Craniopharyngiomas: Case Report and Review of the Literature

Although craniopharyngiomas account for a large percentage of pediatric intracranial tumors, there is a bimodal age distribution. Most of these neoplasms are suprasellar or sellar in location. In this report we describe an unusual case of an infrasellar craniopharyngioma in a child. Only four previous cases of infrasellar craniopharyngiomas with no sellar involvement have been described. Infrasellar craniopharyngiomas are part of the continuum representing intracranial craniopharyngiomas and ameloblastomas of the jaw. A transnasal endoscopic biopsy was performed with a preliminary diagnosis of craniopharyngioma. The patient then underwent a radical resection of the infrasellar tumor via a subfrontal transbasal approach. This case illustrates a rare and unusual location for a craniopharyngioma. Craniopharyngiomas should be considered in the differential diagnosis of infrasellar neoplasms. Infrasellar craniopharyngiomas compromise part of the spectrum of tumors originating from enamel-forming neural crest cells.

Tentorial meningiomas. Report on twenty-seven cases.

Report our experience with 27 tentorial meningiomas (TM) surgically treated between 1985 and 1998. The records of 27 patients with TMs were retrospectively reviewed for clinical presentation, neuroradiological evaluation, surgical treatment and long-term outcome. The extent of tumor resection was scored according to the Simpson's grading for tumor removal. Long-term results were evaluated according to the Glasgow Outcome Score (GOS). The average age was 53 years. Female predominance was 74%. The most common complaints at presentation were headaches (51%), gait ataxia (33%), memory disturbances (30%) and hypoacousia (30%). A classification of TMs into 5 subgroups according to tumor site is proposed on the basis of imaging studies. A cerebrospinal fluid shunt was established prior to direct approach in 7 patients and as the sole procedure in one inoperable patient. Twenty-seven direct approaches were undertaken in 26 patients, including 17 infratentorial and 10 supratentorial approaches. Total tumor removal was achieved in 20 patients (77%) and subtotal removal in 6 (23%). Fifteen patients (55%) experienced 22 postoperative complications. One patient died three months after a subtotal resection (mortality = 3.7%). With a mean follow-up of 54 months, all 26 survivors are currently alive with 23 having resumed their normal activities and 3 needing assistance. Five of 6 patients with subtotal resection survived and were followed for a period ranging from 72 to 132 months: none showed residual tumor progression and no re-operation was considered. An additional patient experienced a (<true>) recurrence 6 years after total removal, with no tumor progression 2 years after his recurrence was recognized. The best surgical approach to TMs is still a controversial matter. The advantages and drawbacks of conventional versus transbasal approaches are reviewed. Our experience suggests that subtotal removal can be associated with long recurrence-free intervals and preserved quality of life. TMs located at the tentorial edge carried a definitely worse prognosis than peripheral forms.

The extended transbasal approach: clinical applications and complications.

To describe in detail key technical aspects of the extended transbasal approach which involves en-bloc mobilisation of the supraorbital rim, the orbital roof and the nasoethmoidal complex. In some patients osteotomies were performed around the cribriform plate with a view to maintaining olfaction. To review 18 patients with deep seated lesions located in the central skull base region (including 6 recurrences) to highlight patient selection, presentation, surgical morbidity and outcome. Prospective data recording and clinical chart review. Outcome was assessed at a minimum of 1 year after operation using the Glasgow Outcome Score. Thirteen patients had made a good recovery, 1 was moderately disabled, 2 were severely disabled (both had been severely disabled before operation), and 2 died. By contrast, quality of life assessment indicated that only 7 of the surviving 14 adults had returned to normal levels of activity and perceived health; although 6 of the other 7 patients had resumed their former occupations, their follow up assessments showed a reduced quality of life. Of the 13 patients who had an olfaction preservation procedure, 6 showed appreciation of smell on formal testing. In patients with progressive and extensive deep seated lesions this technique provides wide exposure in a shallow surgical field. Complication rates although acceptable were significantly higher in patients with intradural lesions. In some selected patients it was possible to preserve olfaction. Specific surgical outcome assessments pointed to satisfactory results, but failed to reflect the degree of patient disability. There is a need for outcome measures that take into account the patient's expectations and which address his quality of life in order to validate the benefits of these procedures.

The extended transbasal approach: a quantitative anatomical and histological study.

Since its introduction in 1972 the transbasal approach to the anterior fossa and sphenoethmoidal region has undergone a number of modifications. The extended transbasal approach with preservation of olfaction not only improves exposure of the anterior fossa, but also provides access to the clivus as far inferiorly as the foramen magnum. An anatomical study has been undertaken to photographically demonstrate and quantify the varying degrees of exposure that this technique provides. The pituitary stalk was used as an intracranial target. The amount of exposure was compared using a standard subfrontal approach, a transbasal approach and an extended transbasal with preservation of olfaction. In addition, a histological study was carried out to investigate the level to which identifiable olfactory nerves extended into the nasal mucosa. The anatomical study demonstrates the area of the "external window of exposure" can be doubled using a transbasal approach and more than quadrupled using the extended transbasal approach, when gaining access to the pituitary stalk. In addition, the study highlights the exposure of other anatomical areas, such as the medial orbit, the cavernous sinus, the clivus and the vertebrobasilar complex. The histological study establishes that the olfactory nerves extend only 10 mms below the cribriform plate.

Extended Transbasal Approach: Anatomy, Technique, and Indications

Appropriate indications for the transbasal approach have not been clearly established. The focus of this study is to determine the feasibility of maximal exposure of the clivus and surrounding regions via this strategy. Further, we sought to determine the key anatomical landmarks and morphometric data necessary for safe, radical exposure. In 20 injected cadaveric specimens, anatomical observations were made grossly and microscopically with 4-40 x magnification. The three basic variations of the transbasal craniotomy were compared with regard to surgical exposure. Maximum exposure of the ventral clivus could be obtained by total ethmoidectomy and sphenoidectomy through the extensive transbasal craniotomy. The lateral limits of exposure were found to be the optic nerves, intracavernous carotid arteries, and hypoglossal canals. Inferiorly, the foramen magnum is the limit of exposure. Morphometric measurements were determined between the key landmarks and were found helpful in subsequent dissections due to the lack of bony structures in relation to neural and vascular structures within the bone. The keys to optimizing the transbasal approach are beyond the simple initial steps of the craniotomy. Maximal exposure from the suprasellar compartment to the foramen magnum is possible via the extended transbasal approach.

Craniofacial Resection: Decreased Compl ication Rate with a Modified Subcranial Approach

The authors have successfully utilized a modified subcranial approach to the anterior skull base, based upon the procedure first described by Joram Raveh, as an alternative to standard craniofacial resection. The complication rate of this procedure in 31 consecutive cases (28 tumors, 2 congenital malformations, and 1 mucocele) has been 19.4% with no permanent complications, no deaths, no new neurological deficits, no brain injuries, no infections, and no seizures. Minor complications without permanent sequelae included two cases of tension pnenmocephalus, a subdural hygroma, two transient cerebrospinal fluid leaks, and a case of bacterial meningitis secondary to fecal contamination of a lumbar drain in a child. Average length of hospitalization was 7.1 days (range 2 to 16 days). The overall complication rate is considerably below the complication rate for other reported craniofacial procedures. We describe the technique we have used and the results. The subcranial approach as described herein provides wide exposure of the anterior cranial base without brain retraction, does not require prolonged operating times or hospitalization, and has a potentially lower complication rate than reported for other transfrontal transbasal approaches.

O-21-311 - The extended transbasal approach: A clinical study

O-21-311 - The extended transbasal approach: A clinical study