Bilateral telovelar approach: A safe route revisited for resections of various large fourth ventricle tumors

Ekkehardm Kasper,Rui Liu

doi:10.4103/2152-7806.126081

Abstract

Background:Tumors located in the posterior fossa and especially in the middle and upper fourth ventricle are comparatively rare and technically very challenging. For some lesions, the telovelar approach has been shown to be a suitable approach. The unilateral approach is sufficient in most cases of small lesions. However, large fourth ventricle tumors are more problematic since they distort the normal anatomy with both vermis and cerebellar peduncles thinned and stretched out. This puts the patient at increased risk for a neurological deficit, which is minimized with a bilateral telovelar approach. By illustrating the adequacy of this technique, we emphasize the suitability of a rather unusual bilateral approach, which will provide excellent panoramic visualization of entire fourth ventricle and thus avoids complications usually associated with resections of large fourth ventricle tumors.Case Description:Here we present three cases of benign intraventricular tumors (meningioma, solitary fibrous tumor and ependymoma) in patients with site specific symptoms from local mass effect. Typical symptoms of posterior fossa lesions were present preoperatively and resolved after surgery. The bilateral telovelar approach was used to remove these tumors completely and the pertinent intraoperative steps are described for each case. All three patients had excellent postoperative outcome and could be discharged after short hospital stays.Conclusion:The different pathological entities could be completely resected without added neurological deficit employing a bilateral approach. In cases of large or giant fourth ventricle tumors, the bilateral telovelar approach provides excellent intraoperative visibility allowing complete excision of extensive tumors with minimal morbidity.

Highlights

Tumors located in the posterior fossa and especially in the middle and upper fourth ventricle are comparatively rare and technically very challenging
Tumors located deep in the posterior fossa and especially in the middle and upper fourth ventricle are challenging to most neurosurgeons
The telovelar approach has been tried out and refined by a number of surgeons and over the past three decades, it has been demonstrated in various settings to be a reliable approach for access to the fourth ventricle.[9,11,13,15]

Summary

Conclusion

The different pathological entities could be completely resected without added neurological deficit employing a bilateral approach. The bilateral tela choroideae, lucent membranes covering the fourth ventricle around the foramen of Magendie, were opened with microinstruments to visualize and access the posterior‐superior part of the fourth ventricle Using this approach, an inferior vermian split was avoided and the caudal vermis could be elevated. Imaging was requested for non‐resolving symptoms and MRI with I/V contrast revealed a multilobulated, irregularly shaped, partially cystic but avidly contrast enhancing, mostly well demarcated tumor, which reached from within the mid fourth ventricle posteriorly toward the inferior velum and laterally into the recess of the fourth ventricle [Figure 3]. The tonsils were retracted, the cerebellomedullary (CM) fissure split and the tela choroidea was opened on both sides to access the posterior‐lateral part of the fourth ventricle Both PICAs were immediately visualized and could be dissected of the tumor mass and the veins of the cerebellomedullary fissure could be preserved. The patient had an unremarkable postoperative course and was discharged to home on POD #4

DISCUSSION

CONCLUSION