Skull base chordomas. A management dilemma

Thursday, 10July 1997 an inter-disciplinary team between 1982 and 1996.82% had malignant lesions. A"geographic site classification system was used for tumor localization. The majority of lesions involved the anterior cranial base and paranasal sinuses. 01 12 patients with esthesioneuroblastomas 75% are alive with no evidence of disease at an average follow-up of 5 years. In the group of patients with squamous cell carcinoma (36) the 4 and 5 year survival was 71% and 65% respectively with 53% beingdisease-free at 4 years. Therewas an overall40% incidence of post-operative complications although the majority were transient and reversible. Only 16% were considered serious complications. Functional statusof our patientsusinga Karnofsky scale revealed 80% to be fully functional and less than 5% severelycompromised. In conclusion, an inter-disciplinary approach to craniofacial resection has had a significant positive impact in survival of neoplasms involving the skull base.

I0-21-311 I The extended transbasal approach: A clinical stUdy B. Evans, S. Honeybul, D. Lang, G. Neil-Dwyer. SUHT, Tremona Road, Southampton, S016 6YD, UK Introduction: The extended transbasal approach involvesen bloc mobilisation of the supraorbital rim, orbital roofsand the nasoethmoidal complex. Methods: 13 patientswith a difficultdeep seated centralskull basetumour are presented highlighting patientselection, surgical morbidity and outcome. In 8 patientsan attemptwas made to maintainolfaction. Resu"s: The patients' ages ranged form 5-80; there were 8 females. All but 1 patient presented with progressive visual failure; 4 had raised intracranial pressure. There were 8 meningiomas, 2 chordomas, 1 invasivepituitary adenoma, 1 craniopharyngioma and 1 fibrous dysplasia. 2 patients had received previous radiotherapy and 6 a prior opera1ion. Overall at 1 yearpostoperatively 10 patients had made a good recovery returning to their former occupations and socialactivities, 1 was severely disabledand 2 died. Of the 8 patients who had an olfaction preservation procedure 4 had appreciation of smellon formal testing. Conclusion: This technique provides wide exposure in a shallow surgical field in patients with progressive and extensive deep seatedpathology. Complication rates were acceptable and most patients had a good outcome. In some selectedpatients it was possibleto preserve olfaction.

I0-21-3121

Skull base chordomas. A management dilemma

Luis A.B. Borba, OssamaAI-Mefty. FederalUniversity of Sao Paulo, Sao Paulo, Brasil, University of Arkansas, Little Rock, USA Because of their critical location, invasive nature, and aggressive recurrence, chordomas remain challenging and, at times, frustrating tumors to treat. Both radicalsurgical removal and high-doseof radiation therapy, particularly protonphoton beam (PB) therapy have been shown to be effective in controlling this tumorand improving survivalrates.We positthat thesepatientsare besttreated by radicalsurgeryfollowedby PB therapy. Duringthe last five years, we treated 24 patientsfor chordoma of the skull base.Thirty-two surgical procedures were performed by us in 22 patients. Radical removal was achieved in 10 patients, subtotal removal in 10, and partial removal in 2 patients. Postoperative proton beam therapy was administered to 17 patients; 2 patients had conventional radiation therapy; and 3 patients had no adjunct therapy. To date, this series has 3 mortalities: a patientwho had undergone a previous surgeryand sacrifice of the ICA and died from massivestroke; 1 patient who died from adenocarcinoma of pancreas; and 1 patientwho died at 25 months secondary to recurrent tumor. Two patients had a permanent cranial nerve deficit. Three patients had complications of the radiation treatment. t last follow-up, mean 25.4 months (range 3-58 months), 16 patients had no evidenceof recurrence,S patientshad recurrence (4 clinicalrecurrence and 1 radiological recurrence) . Although longer follow-up is necessary, we believe that radicalsurgical removal that includenot only the resection of the soft tumor, but an extensive drilling of the surrounding queslionable bone through a wide variety of surgical approaches followed by postoperative proton beam therapyprovidesthe strongest initial meanin treating this tumor. Skull base approaches to this tumor prove to be effective and carry a low mortalityand morbidity.

Tumours of the eNS - Various Locations

SI89

pared. In case of strong lesion adherencewiththe brainstem. the sensitivily and reliability of SEP recording was further analyzed during tumordebulking. Methods: Patients with posterior fossa or upper cervical spine lesions planned for the semi-sitting or the supine position with neck rotation were investigated by pre-operative runcnonal cervicalx-raysand a positivetest for 5 minutes. After induction of general anesthesia (in selected cases with severe brainstem compression fiberoptic endoscopy was performed) median nerve SSEP were set up and controlled continuously during positioning and (at intervals) during surgery. (Unilateral) Amplitude reductions or latency increases werecounteracted by position adjustment, until SEP recovery. Results: During a period of 4 years, position monitoring of the semi-silting position was performed in 1005 patients, with 16 cases of necessary position adjustments in order to achieveSEP recovery. In 4 cases of SEP loss and lack of recovery, positioningand anesthesia had to be stopped, and were justified in view of temporary sensoryand/ormotordisturbances; furtherdiagnosticsand/or cervical disk surgerylfusion were indicated; the procedure was set up again by fiberoptic intubation and positioning in the awake patient. In 3 further cases, basedon theseexperiences, problems were prevented the fiberopticintubation and positioning in the awake patient. In 74 patients position monitoring was performed for the supine position with head rotation, with the necessity of adjustment in 4 cases; in 1 patientthe procedure hadto be stoppedand cervical disksurgerywasrecommended . Significant SEPdeteriorations andabolishment were encountered during tumor debulking of the brainstem in 29 patients; the extent SEP deterioration correlated with the degree of post-operative paresis and/orthe chanceof functional recovery. Discussion and Conclusions: Positioning with neck flexion and especially with neck rotation (in the semi-silting and in the supine position) bear a certain risk of neural compromize in 1. patientswith severe brainstem or uppercervical spinecompression, 2. in elderlypatients withadvancedosteochondrotic cervical changes andlatentcervical diskprolapses, 3. in youngpatientswithhypermobile spines or cranio-cervical anomalies. At least in these candidates continuous monitoring of the SEP during positioning has been proven to be very useful in preventing SEP deteriorating or loss and in minimizing neurological symptoms. In severe adhesion with the brainstem the intraoperative SEP recording is a reliable tool during tumor dissection and may help in setting limits in severely adherent or infiltrative tumors.

I0-21-314 [ jugular Combined neurootological management of glomus tumor: Long term follow-up Akio Morita, Michael J. Ebersold, Kerry D. Olsen, Lynn M. Quast. Mayo Clinic, Rochester, MN, USA, George Washington University, Washington, DC, USA Introduction: Glomusjugulare tumors are benign but locally invasive tumors requiring specific multi-3 years) were reviewed. Median age of patients was 44 (ranged 17-70). Fisch tumor grades were B in 11, C in 3, D1 in 9 and D2 in 10 cases. Seven cases had previous surgeryand 2 had radiotherapy. Multiplechemodectomas were seen in 5 and 3 patientshad familial trail. Result: Totalresection could be achieved in 24 cases (73%). Operativecomplications were cranial nerve deficits including 17 facial weakness (permanent 3), 13 vocal cord. 5 hypoglossal and 6 accessorynerve deficits, CSF leak in 1, and venous hypertension in 1 case. No operative mortality was noted. Tumor recurrence was noted in 8 patients (24%; all cases, 16% after total resection) who were managed successfully with surgery (2) and/or radiotherapy (6). Follow-upKamotskyscore (median follow-up 10 years) were 90 in 23, 80 in 8 and 70 in 1 case. One patientdied of tumorprogression. Conclusion: The oto-neurosurgical approach is very effectivein managing large glomusjugulare tumors for the long term, not only providing control, but with significant chanceof cure. In medicallylow risk patients, surgical excision shouldbe considered as a gold standard for initial treatment. While recurrence rates are relatively high, recurrent tumor can be managed successfully with salvagetreatment. Since cranial neuropathies are frequently encountered preandpost-operatively, meticulOUS careis mandatory topreventserioussecondary complication and medically high risk patient should be directed toward less aggressive management such as radiosurgery.

10 -21-313 1 The use of somatosensory evoked potentials (SSEP) in posterior fossa lesions for patient positioning and surgery C. Matthies, D. Suhr. P. Vorkapic, M. Samii. Dept. of Neurosurgery. Hannover, Germany Introduction: In order to recognize and counteract impending dangers of the semi-sitting position, continuous monitoring of MedianNerveSSEP during patient positioning has been routinely included in our monitoring protocol since 1993. As an alternative the supine position with neck rotation should be com-

I0-21-3151 management Craniospinal tumors and cysts. Some considerations I. Stoev, A. Petkov, L. Petrov, P. Popov. Military MedicalAcademy. Sofia,

Bulgaria The craniospinal junction is a very sophisticated region. Space occupying lesions of this area affect some of the most importantCNS structures mimicking some neurodegenerative and vascular diseasesand consti1uting a seriousdiag-