Persistent Enlarged Occipital Sinus with Absent Unilateral Transverse Sinus

Abstract

The occipital sinus may occasionally remain patent, but the incidence is extremely low and observed in less than 10% of cases. A persistent patent occipital sinus (POS) may be associated with other venous sinus abnormality. The absence of transverse sinus in association with POS is an extremely rare condition and not reported yet. The neuroradiologist, neurosurgeons, otolaryngologist, and neurologist must be aware of the possible existence of POS and other associated venous sinus anomaly, as its warrants very crucial modification of surgical planning, selection of appropriate approaches, and, additionally, may also critically limit the extent of surgical exposure of target, and may hinder intended extent of surgical excision of tumor and associated possibility of injury to POS, which may produce catastrophic hemorrhage, brain swelling, and neurosurgical morbidity. The authors report a 35-year-old male who underwent suboccipital craniotomy for right-side giant acoustic schwannoma. Following the raising bone flap, a markedly prominent, turgid, occipital sinus was observed, not placed exactly in the midline but deviated to the right side, causing further restraining of dural opening. Surgical nuances and intraoperative difficulty encountered along with pertinent literature is reviewed briefly.

Keywords: absent transverse sinus; acoustic schwannoma; patent occipital sinus; posterior fossa; surgical exposure.

Fig. 1

Intraoperative photograph showing persistent dilated, tortuous, occipital sinus (arrow head) with absent transverse sinus (arrow) led to severe restriction of dural opening and grossly minimizing surgical exposure.