# Frontal Sinus Fracture > Frontal sinus fracture for BDS Oral Surgery — anterior and posterior table injuries, CSF rhinorrhoea, nasofrontal duct, obliteration and cranialisation. - Canonical URL: https://prepelephant.com/topics/bds/oral-surgery/frontal-sinus-fracture-bds - Exam / course: BDS · Subject: Oral Surgery - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Frontal Sinus Fracture", PrepElephant, https://prepelephant.com/topics/bds/oral-surgery/frontal-sinus-fracture-bds ## Direct answer Frontal sinus fractures carry consequences far beyond the forehead bruise: displaced anterior tables heal as visible depressions, posterior table fractures risk dural tears with cerebrospinal fluid leak and meningitis, and injury to the nasofrontal duct obstructs drainage, setting up mucocele and mucopyocele years later. Management follows three questions — is the anterior table displaced, is the posterior table displaced or comminuted, and is the drainage duct involved. Undisplaced fractures are observed; displaced anterior tables are reduced and plated; duct injury with damaged mucosa leads to sinus obliteration after removal of all mucosa, while severe posterior table injuries with dural involvement are treated by cranialisation, converting the sinus into part of the anterior cranial fossa. ## What you must remember - **Anatomy first:** the paired frontal sinuses drain through the nasofrontal duct (frontal recess) into the middle meatus; the anterior table is thick and cosmetically critical, the posterior table is thin and fused with dura in places. - **Classification axes:** anterior table versus posterior table versus duct (floor) involvement; each further divided into linear, displaced (more than one table thickness is a common benchmark), and comminuted. - **CSF leak workup:** clear rhinorrhoea with a halo sign on gauze, confirmed classically by beta-2 transferrin assay; most traumatic leaks stop within a week of conservative management — head elevation, avoidance of straining and nose blowing, and antibiotics per unit policy. - **Obliteration principle:** remove every trace of mucosa (bur and diamond drill), occlude the duct, and fill the cavity with fat, bone dust, muscle, hydroxyapatite or a pericranial flap — residual mucosa is the seed of late mucocele. - **Cranialisation:** for comminuted or widely displaced posterior table fractures with dural injury — the posterior table is removed, sinus mucosa extirpated, duct occluded, and the brain allowed to fill the space. - **Late complications checklist:** mucocele and mucopyocele presenting years to decades later, meningitis, pneumocephalus, persistent CSF fistula, osteomyelitis and cosmetic deformity. - **Imaging:** fine-cut computed tomography in axial and coronal planes is mandatory; plain films are useless for surgical planning. ## A typical decision pathway A 24-year-old strikes his forehead on a dashboard. He has a forehead haematoma and, on questioning, admits to a salty nasal drip. Computed tomography shows a displaced anterior table fracture with a minimally displaced posterior table and air in the sinus. The pathway branches at each finding. Clear rhinorrhoea is sampled; beta-2 transferrin confirms CSF, so he is managed with head elevation, stool softeners, instructions against nose blowing and sneezing with an open mouth, and observation — the majority of leaks seal within seven to ten days. The anterior table, displaced by more than its own thickness, is explored through a coronal or seagull incision, reduced and fixed with low-profile miniplates for contour. The critical intraoperative judgement is the nasofrontal duct: if the floor region is fractured and the duct cannot be trusted, obliteration is performed — total mucosectomy under magnification, occlusion of the duct, and filling with abdominal fat — because a blocked, mucosa-lined sinus is a delayed bomb. Had the posterior table been comminuted with a dural tear and brain herniation, the operation becomes cranialisation with neurosurgical cooperation. ## How the exam frames it This topic rewards candidates who think in pathways rather than lists, and Indian examiners reliably test three junctions. The first is the fluid question: "clear discharge after head injury — how do you confirm CSF?" — beta-2 transferrin is the answer that earns the mark, with the halo sign as the bedside clue. The second is the obliteration-versus-cranialisation fork: obliteration for duct injury with an intact posterior table, cranialisation for severe posterior table injury with dural involvement — swapping the two is a common error. The third is the delayed complication: a frontal mucocele presenting ten or twenty years after a forgotten childhood forehead injury is a celebrated clinical case, and the viva expects the candidate to connect the old injury to the new swelling. Always remove all mucosa is the sentence examiners wait to hear. ## Frequently asked questions ### How is CSF rhinorrhoea confirmed? Beta-2 transferrin assay of the clear nasal fluid is the standard confirmatory test; the double-ring halo sign on gauze is a bedside clue. ### When is frontal sinus obliteration indicated? Nasofrontal duct injury or obstruction with damaged sinus mucosa, with an intact or minimally injured posterior table — after complete mucosectomy and duct occlusion. ### What is cranialisation of the frontal sinus? Removal of the posterior table and all mucosa with occlusion of the duct, allowing frontal lobe expansion to fill the sinus — reserved for severely comminuted posterior table fractures. ### Why must all sinus mucosa be removed during obliteration? Trapped mucosa in a blocked sinus secretes mucus and expands over years into a mucocele or infected mucopyocele. ### Which late complication should every frontal sinus fracture patient be warned about? Mucocele or mucopyocele, which can present many years after the injury, plus the small ongoing risk of meningitis with persistent communication.