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Vol 10 No 1 Archive

Presentation Abstracts: Presenting Authors C-D

CHONDROSARCOMA OF THE NASAL SEPTUM RESECTED BY AN ENDOSCOPIC APPROACH

Ricardo L. Carrau, MD (presenter), Barlas Aydogan, MD, Melanie Fukui, MD (Pittsburgh, USA)

Introduction: Chondrosarcoma of the nasal septum is a rare neoplasm. Chondrosarcomas are managed with surgical excision. The oncologic outcome depends on a complete resection as well as the grade of the tumor. Combined treatment is usually recommended for high-grade lesions while surgery is usually sufficient for low-grade lesions.

Description: We present the case of a 37-year-old man presenting with an incidental finding of a large chondrosarcoma of the septum extending into the sphenoid sinus. Review of a CT scan taken at the moment of a motor vehicle accident 3 years prior to our evaluation revealed that the tumor had existed without major change for that length of time.

Results: The tumor was completely resected using a transnasal endoscopic approach obtaining negative margins.

Conclusion: Surgery is the mainstay treatment for low-grade chondrosarcomas. In selected patients, complete resection can be achieved using transnasal endoscopic approaches. Advantages and disadvantages of the endoscopic approach as well as the importance of the endoscopic surveillance will be discussed.

ENDONASAL ENDOSCOPIC REPAIR OF CSF LEAK OF THE SPHENOID SINUS

Ricardo L. Carrau, MD (presenter), Fuat Tosun, MD, Carl H. Snyderman, MD, Amin Kassam, MD (Pittsburgh, USA)

Introduction: The surgical literature lacks a comprehensive clinical study specifically addressing the transnasal endoscopic repair of CSF leaks of the sphenoid sinus.

Description: We retrospectively reviewed the charts of all patients who underwent an endoscopic transnasal repair of CSF leaks of the sphenoid sinus at our teaching hospitals.

Results: Twenty-one patients with CSF leaks of the sphenoid sinuses that were repaired by transnasal endoscopic approach were included in our study. Etiology of the CSF leaks included trauma, surgery, neoplasms, and idiopathic. Grafting materials included banked pericardium, mucosa, turbinate bone and mucopericondrium placed by underlay or onlay grafting or abdominal fat used to obliterate the sphenoid sinus. Nineteen patients were successfully treated on the first attempt. A persistent leak in two patients with previously unrecognized high-pressure hydrocephalus was repaired in a second endoscopic surgery quickly followed by ventriculo-peritoneal shunting.

Conclusion: Following an adequate repair, factors such as etiology, size of the defect, technique and materials used to repair the defect do not significantly affect the surgical outcome. Untreated high-pressure hydrocephalus can lead to a recurrence or persistence of the leaks and should be suspected in patients with post traumatic, idiopathic or recurrent CSF leaks.

ENDOSCOPIC MANAGEMENT OF LESIONS OF THE MEDIAN AND MIDDLE SKULL BASE

Ricardo L. Carrau, MD (presenter), Carl H. Snyderman, MD, Amin Kassam, MD (Pittsburgh, USA)

Introduction: Trans-nasal endoscopic approaches have evolved to include those lesions rising from the lateral and median skull base.

Description: We present our experience with the endoscopic management of CSF leaks as well as benign and malignant tumors arising from the pterygoid and pterygopalatine areas. Details of the technique, their indications, and limitations will be discussed.

Results: The morbidity of this approach compares favorably to traditional approaches. The outcome is similar and is dependent upon on a thorough resection and/or repair of the lesion.

Conclusion: Endoscopic approaches are a reasonable alternative and a valuable adjunct to traditional approaches.

TREATMENT PROTOCOL FOR PATIENTS AT RISK FOR HIGH PRESSURE HYDROCEPHALUS PRESENTING WITH CSF LEAKS

Ricardo L. Carrau, MD (presenter), Amin Kassam, MD (Pittsburgh, USA)

Introduction: The trans-nasal endoscopic approach has become an important tool in the management of patients with CSF leaks of the anterior sellar, and parasellar skull base. The literature reports an 85-100% success rate for the endoscopic repair of CSF leaks, which compares favorably with that reported after transcranial repair. However, there is a sub-population of patients at high-risk for recurrence due to undiagnosed high-pressure hydrocephalus.

Description: We have developed a protocol for the management of patients with CSF leaks and who are at risk for high-pressure hydrocephalus. The protocol includes endoscopic repair, CSF diversion, measurement of CSF pressure after the repair, and immediate VP shunting.

Results: Using this protocol we have been able to identify multiple patients with undiagnosed high-pressure. We have successfully repaired all CSF leaks at >1 year follow-up.

Conclusion: Identification of patients at risk for high-pressure hydrocephalus is important to achieve successful closure of CSF leaks.

OSTEOPLASTIC MAXILLOTOMY FOR TREATMENT OF TUMORS OF THE INFRATEMPORAL FOSSA AND CENTRAL SKULL BASE

Jose F. Carrillo, MD (presenter), Miguel A. Celis, MD, José L. Barrera, MD (Mexico City, MEXICO)

Approaches to infratemporal fossa (ITF) and central skull base are hindered because of the anatomic complexity and deep location of these regions.We describe our experience with the osteoplastic maxillotomy (Catalano), with variants of our own, and an evaluation of oncologic outcomes and quality of life.

Methods: Eight patients underwent an osteoplastic maxillotomy either medial or extended to the infratemporal fossa. 3 cases had diagnosis of malignancy (1 adenoid cystic carcinoma, 1 hemangiopericytoma, and 1 nasal fossa carcinoma with extension to the nasopharynx). 5 cases were nasopharyngeal angiofibromas (NPA) with massive extensions to the infratemporal fossa. Technique consists of a Weber Fergusson incision, to develop facial flaps preserving vascularity to the maxilla. Bone cuts are done through the facial aspects of the maxilla, on the inferior and lateral orbital rims, and on the malar eminence for the medial variant of the procedure, with disengagement of the maxilla laterally. The anterolateral variant also requires descent of the temporalis muscle with preservation of the facial nerve, and an osteotomy at the posterior third of the zygomatic arch, either anterior or through the glenoid cavity. A superficial parotidectomy preserving the facial nerve in cases of massive infratemporal fossa involvement is done. We didn't cut the temporozygomatic branch in any of our cases and resection of pterygoid plates is performed. 4 craniotomies were done: 1 transbasal approach and 3 temporal caniotomies. Reconstruction was performed with titanium plates and temporalis muscle flap was used in 2 cases.

Results: Mean blood loss was 300 cc. 2 patients had the medial and 6 the anterolateral variant of the procedure. Mean follow up was 26 months. 1 palatal dehiscence occurred, in 2 cases extraction of a titanium miniplate was done because of granuloma formation, three cases of frontal facial paresis occurred which resolved spontaneously. From 3 patients with malignancy 3 are alive with no disease, and no recurrences have been recorded in 5 patients with NPA.Evaluation of function and aesthetics (University of Washington Questionnaires) provided excellent results in aesthetics in 6 of 8 patients, and no change in basic functions in 8 patients.

Conclusion: Osteoplastic maxillotomy is an excellent approach for tumors of the nasopharynx and infratemporal fossa (ITF). Wide exposure is obtained which allows resection of massive NPA's with no significant bleeding. Resection of malignant lesions is feasible with good results. Postoperative aesthetics is good and facial nerve function is preserved.

THE TRANSTEMPORAL FAR LATERAL APPROACH TO THE JUGULAR FORAMEN

Peter J. Catalano, MD (presenter), Carlos David, MD, Darsit Shah, MD, Chandranath Sen, MD (Burlington, USA)

Traditional transtemporal approaches to the jugular foramen require facial nerve decompression with varying degrees of mobilization. However, facial nerve dissection and mobilization up to or proximal to the geniculate ganglion is associated with a higher incidence of iatrogenic and ischemic facial nerve injury. Even so, access to the jugular foramen is still limited by the lateral vertebral mass of the first cervical vertebra (C1). A modified Fisch Type A approach combined with a C1 transverse process vertebrectomy allows posterior displacement of the vertebral artery for improved exposure of the jugular foramen, providing better control of local neurovascular structures with less facial nerve mobilization. Potential facial nerve injury is reduced with this approach without compromising tumor resection. The transtemporal-C1 transverse process vertebrectomy approach is presented with a discussion of the relevant anatomy, surgical indications, and operative technique.

PARTIAL LABYRINTHECTOMY PETROUS APICECTOMY APPROACH: A MORPHOMETRIC STUDY

Amitabha Chanda, MD, MCh (presenter), Anil Nanda, MD (Shreveport, USA)

Objective and Importance: Partial Labyrinthectomy Petrous Apicectomy (PLPA) is a relatively new approach to the petroclival region. A morphometric study was done to compare PLPA and Retrolabyrinthine approaches.

Methods: Ten fixed cadaver heads (Twenty sides) were dissected and examined using 3x to 40x magnifications. Mastoidectomy exposed the semicircular canals (SCC). The superior canal was removed completely. The posterior canal was partially removed with preservation of the vestibular aqueduct. The bone above the internal auditory canal (IAC) was drilled to the petrous apex. Temporal craniotomy was performed. The dura was opened. Meckel's cave was opened to mobilize the trigeminal nerve.

Results: Due to the removal of the SCC and bone above the IAC, there was a significant gain of space with limited temporal lobe and cerebellar retraction (TABLES). Conclusion: PLPA enhances exposure with preservation of hearing. Although hearing preservation cannot be evaluated based on cadaveric studies, this approach has been described in the literature.

Tables

Table 1: Comparison between the vertical and horizontal heights of exposure between PLPA and Retrolabyrinthine approach

	Retrolabyrinthine approach		Partial Labyrinthectomy Petrous Apicectomy
	Vertical exposure in mm Mean +/- SD Median Range	Horizontal exposure in mm Mean +/- SD Median Range	Vertical exposure in mm Mean +/- SD Median Range	Horizontal exposure in mm Mean +/- SD Median Range
Right (n=10)	14 +/- 1.9 14 11-18	7.6 +/- 1.03 7.5 6-9	14 +/- 1.9 14 11-18	18.4 +/- 1.6 18 15-21
Left (n=10)	16.2 +/- 2.2 16 12-20	8.2 +/- 1.07 8 6-10	16.2 +/- 2.2 16 12-20	18.5 +/- 2.01 18 16-22

Table 2: Additional exposure after removal of bone above IAC

	Additional exposure in millimeters Mean +/- SD Median Range
Right (n=10)	10.1 +/- 0.9 10 9-12
Left (n=10)	9.9 +/- 1.3 10 8-12

ANOMALOUS JUGULAR BULB CAUSING INTRACTABLE PULSATILE TINNITUS: A TREATMENT OPTION

Amitabha Chanda, MD, MCh (presenter), Laligam N. Sekhar, MD, David A. Schessel, MD (Shreveport, USA)

Objective & Importance: An anomalous jugular bulb rarely can cause symptoms like intractable pulsatile tinnitus. However, no satisfactory treatment exists. A treatment option is described here.

Patients and Methods: From 1998 to 1999 we managed three patients of jugular bulb malformation causing disabling pulsatile tinnitus. All patients were female. Treatment evolved during the period of study and consisted of complete decompression of the bulb transtemporally and isolation from the middle ear. They were followed up for a period of 12 to 20 months.

Results: Tinnitus disappeared in all the three patients after the surgery. There were no postoperative neurological deficits in any patient. One patient had recurrent tinnitus after an accident but the tinnitus gradually improved.

Conclusion: Anomalous jugular bulb can cause disabling tinnitus. The above-mentioned treatment can bring relief. However, more number of patients and more follow up are necessary for making this a standard method of treatment.

ORBITOZYGOMATIC TRANSCAVERNOUS TRANSSELLAR TRANSCLINOID APPROACH TO BASILAR ARTERY BIFURCATION: AN ANATOMIC STUDY

Amitabha Chanda, MD, MCh (presenter), Anil Nanda, MD (Shreveport, USA)

Objective and Importance: An anatomical study is made to demonstrate that the Orbitozygomatic Transcavernous Transsellar Transclinoid approach provides satisfactory exposure to the basilar bifurcation and trunk.

Methods: Bilateral stepwise dissections were performed on five fixed cadaver heads using 3x to 40x magnifications. A frontotemporal craniotomy with orbitozygomatic osteotomy was made. The anteromedial triangle of the cavernous sinus was opened to mobilize the internal carotid artery medially. Sylvian fissure was opened widely. Sella and the dorsum sella were exposed. The posterior clinoid process and dorsum sella were drilled to expose a length of basilar artery with its bifurcation.

Results: Excellent exposure of the basilar artery trunk and its bifurcation and neurovascular structures in the interpeduncular and prepontine cisterns were obtained.

Conclusion: This approach combines the advantages of most of the conventional approaches to the basilar tip aneurysm. Also, it exposes sufficient length of basilar trunk to place a temporary clip.

MICROSURGICAL ANATOMY OF INFRALABYRINTHINE APPROACH

Amitabha Chanda, MD, MCh (presenter), Anil Nanda, MD (Shreveport, USA)

Objective and Importance: Infralabyrinthine compartment, which is crowded by major vessels and cranial nerves, can be accessed by infralabyrinthine approach. This study demonstrates the microsurgical anatomy of the infralabyrinthine approach.

Methods: Bilateral stepwise dissections were made on five fixed cadaver heads (Ten sides) under 3x to 40x magnifications. After mastoidectomy facial nerve was transposed anteriorly. Neck dissection was done to expose the cervical internal carotid artery (ICA), internal jugular vein and lower cranial nerves. Drilling of the lateral tympanic bone was followed by exposure of the jugular foramen and intratemporal ICA.

Results: Excellent exposure of the infralabyrinthine compartment (area posterior to the infratemporal fossa and lateral to the basiocciput and occipital condyle) was achieved.

Conclusion: This approach is suitable for glomus jugulare tumor, malignancies of mastoid bone, and middle ear and distal cervical ICA aneurysm. Apart from excellent exposure it provides good proximal and distal control of the large vessels.

RECONSTRUCTIVE MANAGEMENT OF CRANIAL BASE DEFECTS FOLLOWING TUMOR ABLATION

David W. Chang, MD (presenter), Franco DeMonte, MD, Howard N. Langstein, MD, Abhay Gupta, MD, Geoffrey L. Robb, MD (Houston, USA)

Purpose: to assess the impact of potential risk factors on rates of complications and patient survival, and to identify reconstructive management principles for achieving successful cranial base reconstruction.

Methods: 77 cranial base reconstructions performed by the Department of Plastic Surgery at our institution between 1/93 and 9/99 were reviewed.

Results: Reconstructive methods included free flaps in 52(68 %), temporalis muscle flaps in 14(18 %), and other local flaps (eg. pericranial) in 11 patients (14 %). Complications occurred in 21 patients (27 %). Overall survival was 77 % at 2 years and 58 % at 4 years. The type of reconstruction, location of defect, type of dural repair, and history of preoperative radiation and chemotherapy had no significant association with the incidence of complications. Neither the type of reconstruction nor the location of defect showed a significant effect on patient survival.

Conclusion: Local flaps, such as pericranial or temporalis muscle flaps, are good choices for reconstruction of smaller anterior or lateral cranial base defects. For large or complex defects, free flaps are appropriate. With proper patient selection, successful cranial base reconstruction can be performed with either local or free flaps with a low incidence of complications.

NON-SYNDROMIC CRANIOSTENOSES: ANALYSIS OF 103 OPERATED CASES

Marcus Vinicius Martins Collares, MD, PhD (presenter), Rinaldo de Angeli Pinto, MD, Roberto Corrêa Chem, MD, PhD, Nelson Pires Ferreira, MD, Marcelo Paglioli Ferreira, MD, Jorge Kramer, MD (Porto Alegre, BRAZIL)

This is a retrospective, hospital-based study, whose objective is to review our experience with the surgical treatment of non-syndromic craniostenoses at Hospital São José and at Hospital de Clínicas, in Porto Alegre, RS, Brazil, from August, 1991 to May, 2000. The sample was constituted of 103 patients (56 females and 47 males). The average age was 7.2 months, and the average weight was 7.8 kg. The cranial deformities found were: scaphocephaly (49 cases), plagiocephaly (21), trigonocephaly (14), brachycephaly (11), and oxycephaly (4). In multiple craniostenoses, the deformities were: posterior scaphoplagiocephaly (2 cases), and anterior and posterior brachycephaly (2). There were no surgical complications in 96 patients. Two patients died (hypovolemic shock and postoperative respiratory dysfunction). There was an estimated volemia loss of 32% during the transoperative period, and an equivalent initial volemia loss of 27% 48 hours after surgery (suction drain). Mean surgery time was 185 minutes, and mean postoperative hospitalization time was 6.4 days. A multidisciplinary approach and appropriate training of the clinical-surgical staff minimize the risks and decrease the complications in the treatment of craniostenoses. Our results are similar to the ones reported in the literature.

VIDEO ENDOSCOPIC SURGERY IN CRANIOFACIAL ANOMALIES

Marcus Vinicius Martins Collares, MD, PhD (presenter) (Porto Alegre, BRAZIL)

The development of endoscopic techniques and materials is changing some traditional aspects of surgery. The endoscopic surgery is routinely used in many medical fields. The videoendoscopic surgery allows minimal surgical incisions and image magnification, becoming a powerful tool to be employed in difficult anatomical areas.

Endoscopic has been largely used for diagnostic purposes in the craniofacial area. Endoscopic or endoscopic-assisted surgery is currently broadening its use in all craniofacial fields such as congenital anomalies, trauma, aesthetic, development anomalies and tumors.

At our institution the videoendoscopic surgery has been used for trauma (condyle, zygomatic, orbital and maxillary fractures); congenital anomalies (osteotomy and placement of bone distraction devices; costal cartilage harvesting for craniofacial reconstruction, intra-operative checking of bulboplasty); development anomalies (orbit osteotomies for Graves disease, galeal flap harvesting); aesthetic (brow and mid-face lift); tumors (sinusal and intra-cranial).

The use of endoscopic surgery needs specific training to be adapted to the bidimensional system, to the limited operation field and to a distant tissue manipulation. Another critical point is the development and adaptation of new devices to improve surgical comfort and time.

The indication and effectiveness of using the videoendoscopy in the craniofacial surgery is discussed. New instruments developed to make our surgical approaches easier are also presented.

In summary, the endoscopic surgery can minimize surgical trauma and morbidity, but requires special instruments and specific training. After the learning curve, it can be useful in all craniofacial areas.

THE TEMPOROPARIETAL FASCIAL FLAP IN CRANIAL BASE NEUROSURGERY

Peter D. Costantino, MD (presenter), Chandranath Sen, MD, Caleb R Lippman, MD, David Hiltzik, BA (New York, USA)

The temporoparietal fascial flap (TPFF) is a thin, well vascularized flexible flap based on the posterior branch of the superficial temporal artery (STA) and vein. This flap has a substantial blood supply and minimal bulk, and has therefore been used successfully in surgical reconstructions that necessitate a thinner construct, including those of the periorbita, ear, paranasal sinuses, scalp, larynx, and trachea. Here we describe our experiences with the TPFF in skull base reconstruction. This flap was used in 30 patients undergoing cranial base surgery between 1997 and 2000. The pathologies included squamous cell carcinomas (n=7), sarcomas (n=5), meningiomas (n=4), adenocystic carcinomas (n=4), chordomas (n=3) , schwannomas (n=2), infection, fibrous dysplasia, glomus cell tumor, and esthesioneuroblastoma (n=1 each). Sixteen cases were recurrent tumors, and 14 were primary. Tumor location included the infratemporal fossa floor (n=12), anterior fossa floor (n=9), orbit (n=9), ethmoid sinus (n=7), clivus (n=5), temporal bone (n=4), maxillary sinus (n=5), jugular foramen (n=3), parotid gland (n=3), nasal cavity (n=2), sphenoid sinus (n=2), and posterior fossa, glenoid fossa, frontal sinus, and hard palette (n=1 each). The TPFF was used unilaterally (n=26) or bilaterally (n=4), and sometimes in conjunction with a pericranial flap (n=5), a rectus muscle free flap (n=5), a temporalis muscle flap (n=1), or titanium mesh (n=2) for cranial and orbit reconstruction. Alloderm was used for duroplasty in 15 patients. None of the patients experienced any postoperative CSF leak, wound breakdown, hematoma, or volume loss. One patient developed a post-radiation osteomyelitis of the frontal bone flap, and a second had significant alopecia at the incision site. There were no cosmetic volume deformities from the use of the TPFF, in contrast to the temporal hollowing seen with the temporalis muscle flap. We conclude that the TPFF flap is an extremely useful flap for skull base reconstruction. We strongly believe that its use substantially enhances wound healing, minimizes the incidence of postoperative CSF leaks and infection, and is not associated with post-operative cosmetic deficits. We now utilize this flap as our primary means of lateral, infratemporal, and clival skull base defect reconstruction.

DEVELOPMENT & VALIDATION: QUALITY OF LIFE QUESTIONNAIRE FOR CUSHING'S DISEASE PATIENTS

Michael D. Cusimano, MD, FRCSC, PhD (presenter), Anthony Marchie, BSc, Fateme Salehi, Harley S Smyth, MD, DPhil, FRCS(C) (Toronto, CANADA)

Introduction: Patients with pathologically-verified Cushing's disease (CD) have a range of symptoms such as obesity and depression. Understanding the impact of CD on quality of life (QOL) is important in choosing appropriate treatment. No such QOL assessment exists for these patients. The purpose of this study is to develop and validate a CD-specific health-related quality of life (HRQOL) questionnaire (QU).

Method: Focus group interviews and literature review were used to develop a QU with 177 items. These items were sorted into 5 domains: physical, cognitive, social, emotional, and medical. 22 patients completed the QU and feedback was given. Impact scores were based on a 7-point scale: 1=least; 7=most affected. T-tests (p<0.05) were used to compare the means of each domain. Validity was assessed by Pearson correlation coefficient between the QU and the Karnofsky Scale (KPS).

Results: Mean scores and standard deviations for each domain were: physical (4.29, 1.46); cognitive (3.91, 0.57); social (2.97, 1.23); emotional (5.07, 1.11); and medical (3.50, 1.72). Validity coefficient was 0.63 for general health (KPS). Physical (p=0.028) and emotional health (p=0.0002) had greater impact on QOL than other domains. Despite having less impact, cognitive health (p=0.035) and medical treatment (p=0.029) were rated as highly relevant to QOL; the opposite was found for physical health (p=0.02). The social domain was least affected by CD and had the least relevance to QOL. 73% of the patients felt the QU captured an accurate sense of their QOL; 14% thought otherwise, and 13% did not give an opinion.

Conclusion: A HRQOL QU was developed for patients with Cushing's disease. Preliminary evidence for validity was demonstrated. Domains may unequally influence a CD patient's perception of QOL. Dual scaling will be explored as a means to reduce the number of QU items and to help understand better the meaning of the responses.

THE USE OF A SKIN SEALANT IN TREATMENT OF CSF LEAKAGE

Michael D. Cusimano, MD, FRCSC, PhD (presenter), Brian Rotenberg, MD, Anthony Marchie, BSc (Toronto, CANADA)

Cerebrospinal fluid (CSF) wound leak is a common postoperative complication in neurosurgical and otolaryngological procedures. There exist numerous strategies for the resolution of this potentially serious complication. Liquid skin sealants have only recently been recognized as a possible treatment. A case of a postoperative CSF leak treated with a liquid skin sealant (Dermabond®, Ethicon, Somerville, NJ) is presented. The use of such skin sealants represents a new simple, effective and low risk strategy for the management of CSF leakage, and warrants further exploration.

ZYGOMATIC APPROACH TO CRANIOPHARYNGIOMAS

Haluk Deda, MD (presenter), Hasan Caglar Ugur, MD, Efkan Colpan, MD (Ankara, TURKEY)

Craniopharyngiomas frequently invade both supra and infrachiasmatic cistern and have close association with interpeduncular cistern. Thus, it is difficult to plan a safe dissection of giant craniopharyngiomas. However, zygomatic approach not only enables the surgeon to secure the important vascular and neural structures but also facilitates the tumor dissection easily.

Between the years of 1995 and 2000, 10 giant craniopharyngioma cases were operated through the zygomatic approach. In all the cases, the tumor was invasive of the interpeduncular cistern and 3rd ventricle. In 8 of the 10 cases, a total tumor resection was achieved while in remaining two, subtotal resection was possible. All the neuronal and vascular structures were protected. There was no neurological deficit in the patients who received a total excision following the operation. Two patients who received subtotal excision were previously operated in other centers. Three patients have been receiving hormonal treatment. One of the patients who received a sub-total excision was given post-operative radiotherapy. All the cases are able to carry out their daily tasks.

This report aims at discussing the advantages of zygomatic approach in giant craniopharyngioma cases.

THE PETROUS CAROTID ARTERY: A RADIOANATOMIC CADAVER STUDY

Haluk Deda, MD (presenter), Funda Batay, MD, Aysun Uz, MD, Faik Ozveren, MD, Eray Tuccar, MD, Alaittin Elhan, MD, Ibrahim Tekdemir, MD (Ankara, TURKEY)

The carotid artery, cochlea and the facial nerve are the most vulnerable structures within the temporal bone. Displaying these structures and their relations with one another should be considered in choosing the most appropriate skull base approach. The axial computed tomography images can show us the dehiscences within the horizontal segment of the carotid artery canal and the relation of the petrous carotid artery with the cochlea. In this study, 24 dry temporal bones, 12 cadaver specimens and the computed tomography images were examined. The distances between petrous carotid artery, foramen spinosum and ovale and cochlea were measured. It is aimed to put forward the relationships of the internal carotid artery with the surrounding structures such as the foramen ovale, foramen spinosum, greater petrosal nerve, tensor tympani muscle, auditory tube and the cochlea. Furthermore, the comparative CT images will be helpful to build the preoperative strategy accurately.

ANTEROLATERAL SKULL BASE TUMORS

Franco De Monte, MD (presenter), Yashail Y. Vora, MD, Edguardo Diaz, MD, Jeffrey N. Myers, MD, Dima Abi-Said, MD (Houston, USA)

Introduction: Neoplasms involving the anterolateral skull base are rare. We describe our experience at a major cancer referral center.

Methods and Materials: Records of patients since 1992, presenting with neoplasms involving the base of the skull bounded medially by sphenoid sinus, anteriorly by the sphenoid wings, and laterally by petrous internal carotid artery, were retrospectively reviewed.

Results: The median age of 28 patients was 47 years. Sarcomas were the most common tumors (46%). Squamous-cell carcinomas, chordomas and atypical/anaplastic meningiomas totaled 36%. Spread to the dura, brain or along perineural space occurred in 43%. Patients frequently required multiple surgeries (60%), chemotherapy (71%) and radiotherapy (61%). Median follow-up spanned 3.8 years. Median time to recurrence was 18.9 months with 36% of the patients being alive without cancer and 32% with cancer while 21% of patients had died from cancer. 2 patients were lost to follow-up and 1 patient died of pulmonary embolism. The 1-year and 5-year survivals were 88% and 63% respectively.

Conclusion: Anterolateral skull base tumor management is challenging. Tumor control and a useful survival benefit can be achieved in most patients.

ANTERIOR CRANIOFACIAL RESECTION IN THE PREVIOUSLY IRRADIATED PATIENT

Eduardo M. Diaz, Jr., MD (presenter), Jeffrey N. Myers, MD, Yashail Y. Vora, MD, Franco DeMonte, MD, FRCSC (Houston, USA)

Background: Anterior craniofacial resection has been shown to be an effective alternative for the surgical control of malignancy of the anterior skull base. While the majority of these procedures are performed either alone or in conjunction with postoperative radiation, it is often necessary to consider this option as salvage in the previously irradiated patient. We reviewed our experience over the last ten years in order to establish success rates and rates of complication for patients with disease of varied histology in an area previously irradiated either immediately prior to surgery or in the remote past.

Methods: We reviewed the charts of 254 patients who underwent an anterior craniofacial resection during the period between September 1990 and September 2000.

Conclusions: Salvage anterior craniofacial resection after radiation is a viable alternative in the indicated patient. However, patient selection is important, as patients are susceptible to higher rates of complication.

MANAGEMENT OF SKULL BASE NEUROFIBROMATOSIS

Vincent DiNick, MD (presenter), Ian T. Jackson, MD (Southfield, USA)

Skull base neurofibromas are exceedingly challenging problems to deal with from many points of view. Firstly, to establish a true impression of the three-dimensional deformity can be difficult. An MRI scan will show the distribution of the soft tissue component and a CT scan can outline bony changes. However, to truly plan effective surgical rehabilitation it is helpful to have three-dimensional CT scanning, particularly of the interactive type and by far the most comprehensive at the present time is ANALYZE (Biomedical Imaging Systems, Mayo Medical Foundation, Rochester, Minnesota, USA). Using this system, it is possible to completely assess the deformity, to measure area and volume changes, and to perform mock surgery. An additional important investigation is angiography since many of these tumors can be extremely vascular and surgery on them can be a daunting experience.

The distribution of most skull base neurofibromatosis is a temporal orbital facial one; it is almost like a syndrome with a variable anatomical presentation. The soft tissue of the side of the head, including the ear and the eye, can be affected. The eye may or may not have vision. The sphenoid wing, the temporal fossa, and the orbit can be grossly deformed - from displacement to absence.

It has been found convenient to group the condition into three groups. The first one where the involvement is mainly soft tissue with a seeing eye. In these cases, debulking is performed if and when indicated. In group II, there is considerable bony involvement. There may be thinning of the temporoparietal area with an increase in lateral projection of the middle cranial fossa. The orbit may be greatly enlarged and egg-shaped with a varying defect in the posterior orbital wall due to absence of the sphenoid. The malar and zygomatic arch are hypoplastic. In these cases, the eye is kept at all costs. The middle cranial fossa may be decreased in size and the herniated portion of brain or arachnoid cyst displaced back intracranially. It has been found that a heavy metal mesh is best for replacement of the temporal region. The defect in the posterior wall of the orbit is bone grafted and the orbit itself is reduced in size to the same dimensions as the other side. The neurofibroma within the orbit is resected. The neurofibroma of the cheek area is resected and the ear is repositioned.

In Group III, the eye is often buthalmic, being involved in the condition. The bony deformity is more significant, frequently the same is true for the soft tissue deformity. In these cases, the eye is sacrificed. The previously described bony corrections are carried out and the soft tissue around the eye is dealt with using whatever method is possible. If the lids can be preserved, then every effort is taken to do so. If not, the skin of the lids may be used to line the socket and an external eye and eyelid prosthesis provided. If a large amount of tissue is resected from the cheek, then free tissue transfer is used in reconstruction of the cheek.

Experienced based on a series of 25 cases will be presented. Although the results of many of these leave a lot to be desired, they are encouraging. No patient wears an eye patch and all of them are gainfully employed which contrasts sharply with the preoperative situation, at that time they all kept the eye covered and only a few of them had jobs. It is considered that careful analysis of the deformity, extensive correction, and the use of osteotomies, bone grafts and free tissue transfer can rehabilitate these patients to a very significant degree.

MICROSURGICAL RESECTION OF MENINGIOMAS ARISING FROM THE FLOOR OF ANTERIOR CRANIAL FOSSA

Aclan Dogan, MD (presenter), Satish Sathyanarayana MD, Sherif Abdallah MD, Anil Nanda MD (Shreveport, USA)

Introduction: The authors report 16 cases of meningioma of the floor of anterior cranial fossa treated microsurgically over the last 8 years.

Methods: There were 12 women and 4 men between the ages of 43 and 66 (mean age, 56). Mean duration of clinical history was 30 months. Sphenoid wing was the most frequent location (12 cases) followed by olfactory groove and planum sphenoidale. Headache, seizure, and blurred vision were the main complaints. Decrease in visual acuity was present in 56 % of cases. Surgical approaches used were frontotemporal in 10 cases, bifrontal in 3 cases, pterional in 2 cases, and pterional with transzygomatic orbital osteotomy in 1 case.

Results: Complete removal was performed in 13 cases (81 %); in the remaining 3 (19 %), partial removal was performed because of arterial and cranial nerve encasement. There was no mortality. In the postoperative period, new cranial nerve deficit was developed in 2 patients. Although there was no tumor recurrence, seizure was the main symptom during follow-up periods.

Conclusion: Our experience suggests that the meningiomas of the anterior cranial fossa floor can be removed completely without mortality and acceptable morbidity.

THE REQUIREMENT OF OCCIPITAL CONDYLE RESECTION IN FAR-LATERAL APPROACH TO ANTERIOR FORAMEN MAGNUM LESIONS

Aclan Dogan, MD (presenter), Mustafa Baskaya MD, David A. Vincent, MD, Anil Nanda MD (Shreveport, USA)

Objective: To determine whether drilling out the occipital condyle facilitates surgery via the far-lateral approach, we compare 10 clinical cases with studies from 8 cadaver heads.

Methods: In the last 6 years, 10 patients have been operated on via the far-lateral approach to the foramen magnum. Six of these patients had anterior foramen magnum meningiomas, 1 had a dermoid cyst, 1 had rheumatoid disease of the craniocervical junction, and 2 suffered vertebral artery aneurysms. The approach consisted of retromastoid craniectomy and C1 laminectomy. The increase in the area of exposure that is gained by fractional removal of the occipital condyle was quantified by measuring the degrees of visibility on eight cadaveric specimens.

Results: The 7 tumors and pannus of rheumatoid disease were completely excised and the 2 aneurysms were clipped without drilling of the occipital condyle. No patients had complications associated with surgery. All had improved neurological function postoperatively. In the cadavers, removing one-third of the occipital condyle produced a mean increase of 15.9º visibility, and removing one-half produced a mean increase of 19.9º.

Conclusion: We suggest that removal of the occipital condyle is not necessary for the safe and complete resection of anterior intradural foramen magnum tumors.

TENSION PNEUMOCEPHALUS

Paul J. Donald, MD (presenter), (Sacramento, USA)

Tension pneumocephalus is a potentially life-threatening complication of cranial base surgery. The talk will focus on the etiology, treatment and prevention of this complication. The various theories of pneumocephalus will be explained. The specifics in the five cases of pneumocephalus in the UC Davis series will be discussed.

RADIOLOGICAL AND CLINICAL DETERIORATION OF HISTOLOGICALLY BENIGN TUMORS FOLLOWING STEREOTACTIC RADIOSURGERY