Surgical Approaches to the Middle Cranial Base Tumors

OBJECTIVE: We analysed various surgical approaches and surgical results of 28 middle cranial base tumors for the purpose of selecting optimal surgical approach to the middle cranial base tumor. METHODS: In this retrospective review, 28 patients, including 16 meningioma, 6 trigeminal neurinoma, 2 pituitary adenoma, 2 craniopharyngioma, 1 facial neurinoma, and 1 metastatic tumor, underwent surgical treatment using skull base technique. Of theses, 16 tumors were mainly confined to middle cranial fossae, 5 tumors with extension into both anterior and middle fossa, and 7 tumors with extension into both middle and posterior fossa. Tumors that confined to the middle cranial fossa or extended into the anterior cranial fossa were operated with modified pterional, orbitozygomatic or Dolen'c approach, and tumors that extended into the posterior cranial fossa were operated with anterior, posterior or combined transpetrosal approach. Completeness of tumor resection, surgical outcome, postoperative complication, and follow up result were studied. RESULTS: Total tumor removal was achieved in 9 tumors of 10 tumors that did not extended to the cavernous sinus, and was achieved in 7 tumors of 8 tumors that extended to the lateral wall of the cavernous sinus. Of 10 tumors that extended to the venous channel of the cavernous sinus, only 2 were removed totally. Surgical outcome was excellent in 14 patients, good in 10, fair in 2 and poor in 2. There were no death in this series. Dumbell type tumor which extended into both middle and posterior fossae showed tendency of poor prognosis as compared with tumors that confined middle cranial fossa and extended into both anterior and middle cranial fossa. Postoperative dysfunctions were trieminal hypesthesia in 3, oculomotor nerve palsy in 2, abducens nerve palsy in 2, hemiparesis in 2, cerebellar sign in 1, facial palsy in 1 and hearing impairment in 1. CONCLUSION: Based on our findings and a review of the literature, we conclude that, when selecting the surgical approach to the middle cranial fossa tumors, the most important factors to be considered were exact location of the tumor mass and existence of the cavernous sinus invasion by tumor mass. We recommend modified pterional or orbitozygomatic approach in cases with tumors located anterior and middle cranial base, without cavernous sinus invasion. In cases with tumors invading into cavernous sinus, we recommend Dolen'c or orbitozygomatic approach. And in lateral wall mass and the cavernous sinus, it is preferred to approach the tumor extradurally. For the tumor involing with middle fossa and posterior fossa(dumbell type) a combined petrosal approach is necessary. In cases with cavernous sinus invasion and internal carotid artery encasement, we recommend subtotal resection of the tumor and radiation therapy to prevent permanent postoperative sequele.

SPECT Imaging of Dopamine Transporter with I-123 IPT in Normal Controls and Parkinson's Patients

OBJECTIVES: Dopamine transporter concentrations have been known to decrease in Parkinson's disease(PD). The aim of the present study was to evaluate the correlation between SPECT measurements of [I-123]N-(3-iodopropene-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane(IPT) as an imaging agent for measuring changes in transporter concentrations with PD. PATIENTS AND METHODS:IPT labelled with 4.87+/-1.29mCi(180.19+/-47.73 MBq) of [I-123] was intravenously injected into 23 patients(age:58+/-12) with PD and three normal controls(NC)(age:37+/-7) as bolus. Brain SPECT were then performed at 1 hour and 2 hours after injection on a double headed camera. The statistical parameters were the contrast ratio of left basal ganglia(BG) and right basal ganglia to occipital cortex(OCC) per milli curies of injected radiotracer at 1 hour and 2 hours. The correlations were evaluated between these parameters and Hoehn-Yahr classification of the patients. RESULTS: The(BG-OCC)/OCC/mCi ratios at 1 hour and 2 hours for PD and NC were 0.14+/-0.07 and 0.27+/-0.07(1 hour) and 0.12+/-0.07 and 0.34+/-0.04(2 hour), respectively. The(BG-OCC)/OCC/mCi ratios of Parkinson's disease were decreased with higher grade of Hoehn-Yahr classification of the patients. The ratio between BG and OCC for PD were clearly separated from NC and may be useful outcome measures for clinical diagnosis. CONCLUSION: The findings suggest that IPT may be a very useful tracer for early diagnosis and treatment of PD and study of dopamine re-uptake site.