| Chordomas belong to rare malignant primary bone tumors, arising from remnants of the embryonic notochord. And they grow slowly and invasively. The sacrococcygeal region and the skull base represent the most common sites.The skull base chordomas locate deep and have a closed relationship with surrounding vessels and cranial nerves. The age ranges from 3 to 95 years according to the references. Discontinuous and extensive headache represents the most common clinical manifestation and diplopia which is caused by abducent nerve deficiency follows.Some cases present vision short-sightedness, nasal obstruction,dysfunction of pituitary gland and so on. Its treatment is intractable because chordoma has less sensitivity to radiotherapy and chemotherapy is useless. Chordoma has a bad prognosis and patients will suffer from death after diagnosis in 3 or 4 years,which is caused by the damage of vital vessels and nerves.Post-radiotherapy can prolong the life-time of the patients. Presently the main therapy of skull base chordomas are surgical operations.And surgical approaches include transnasal transsphenoidal approach and transcranial approach.So the choice of the approach is extremely important. The transnasal transsphenoidal approach is widely used for chordomas of the upper and middle clival and sellar region. The surgical route is short and view is clear.The postoperative applications are also few.This approach has a wide application prosperity.The therapy of skull base chordomas have lots of new advances along with the development of skull base surgery,stereotactic radiosurgery, neuro- navigation and neuro-endoscopy.Objective: To investigate the experience of clinical efficacy, surgical indications and postoperative complications in microsurgery of skull base chordoma by transnasal transsphenoidal approach and conduct a comparison statistically between transsphenoidal approach and transcranial approach with the rate of total excision and incident postoperative complications.Method: A retrospective review of 25 patients suffering from skull base chordoma diagnosed by virtue of pathological and immuno- histochemical methods was performed between January 2004 and December 2008.There were 9 male patients and 16 female patients ranging from 32 to 59 years old, with a median age of 45.4 years old. All the patients were conducted first operations without preoperative radiotherapy. The course of disease ranged from 2 months to 15 years, with a median course of 1.5 years old.Headache was the most common clinical sign with 19 cases and diplopia was followed with 14 cases. Abducent nerve deficiency was clinical symptom with 12 cases. All the cases were conducted skull base CT scanning and cranial MRI pre-operatively. The CT of the skull base displayed the tumor on the clivus, saddle area and nasopharynx. The boundary of the tumor is not clear. The morphous of the tumor is not regulated.It is sub-lobed or noduled with widespread osteolysis bone destruction around. The tumor presente the confounding or equal density, with the calcification of nodules. One or several low density areas sometimes present in the tumor. There are widespread bone destruction and calcification of nodules dispersed in the tumor on the clivus in the bone window level of CT. The tumor in the MRI is equal and low T1WI signal intensity and medium or extremely high T2WI signal intensity. Chordoma is always medium or conspicuous intensified in contrast scan of MRI.Occasionally ,it is slightly intensified or no intensified.The main parts of all tumors were located sellar region, upper and middle clivus. Of all the cases, eight cases presented the extension to sphenoidal sinus. Five optic nerves were raised and compressed. Five cases presented compression of brain stem. Four cases presented the extension to unilateral or bilateral cavernous sinuses. Two tumors invaded nasopharyngeal cavity. Two tumors involved ethmoidal sinuses. According to the MRI,the maximum diameters ranged from 3.0 to 5.4cm with the average 4.1cm. The transnasal transsphenoidal approach microsurgery was used to accomplish resection of the lesions involving the clivus and extending up to the parasellar region in all cases. And two cases were guided by neuronavigation. We slected 30 patients who suffered from skull base chordoma diagnosed by virtue of pathological and immunohistochemical methods. This class consisted of 17 male patients and 13 female patients ranging from 19 to 67 years old, with a median age of 48.5 years old and the course of disease ranged from 6 months to 10 years with a median course of 2 years old. Results: 21 cases represented classical chordomas and 4 cases represented chondroid chordomas.The immunohistochemistry showed that S-100,CK and EMA were positive in chondroid chordomas,which demonstratede that they were originated from epithelium.In the same time,Vim was also positive,which demonstratede that they had the tendency to differentiate lobus intermedius. Complications included death, CSF lesk and intralcranial infection were not presented. 16 cases in 19 patients got their headache ameliorating and the rate of the amelioratement was 84%. 6 cases in 9 patients got their vision and view improving. Chordomas belong to rare malignant primary bone tumors which invade skull bone widely,so the total pathological resection is not available.The standard of the total resection is complete excision in operation and no tumor imaging is visible after conducting post-operative imaging test.According to this standard, total and partial resections of the tumor were achieved in 21 and 4 patients respectively and the rate of total excision was 84%.In transcranial approach group, total and partial resections of the tumor were achieved in 18 and 12 patients respectively and the rate of total excision was 60%. Fish exact test was processed, P=0.053>0.05 and this was not statistically significant underα=0.05.There were 3 cases with postoperative complications in transsphenoidal group and the rate of postoperative complications incidence was 12%.One case was encountered post- operative oculomoter nerve palsy and another case was encountered diabetes insipidus, which were back to normality after leaving hospital. One case presented with new hemiparesis postoperatively and the muscle strength of the right limb was grade 3 because of compression of brain stem and the edema of brain stem and vasospasm. The muscle strength of the right limb was back to grade 4 after leaving hospital. In transcranial group,11 cases suffered postoperative complications including intralcranial infection, diabetes insipidus(electrolyte disorders),digestive tract hemorrhage and so on.The rate of post- operative complications incidence was 37%.Fish exact test was processed, P=0.036<0.05 and this was statistically significant underα=0.05.The average operation time and hospitalization time were 50min and 7d respectively in transsphenoidal group. In transsphenoidal group , operation time was more than 2h and hospitalization time was more than 10d.Conclusion: The transnasal transsphenoidal approach allows a rapid, extracerebral, direct exposition of the clival and parasellar region. The main limits of the approach are represented the tumor being primarily centered on the inferior clivus or extended to the occipital condyle , a significant lateral extension of the tumor, and extensive intradural invasion of the tumor. The advantages of transnasal trans- sphenoidal approach have small trauma with short time for operation. Postoperative applications are few. The expense of operation is reduced. And complete excision rate is high. This approach is available for primarily centered on the superior and middle clivus and extended to the parasellar region. |
