Lesson learned from Linnc Asia 2019 and put to use 3 years later - Drilling the IPS

• a 60-year-old diabetic female patient who presented with redness in her left eye
• Ophthalmological evaluation and cross-sectional imaging of a suspected left-sided carotico-cavernous fistula

Left ECA and ICA angiography

• Dural AV fistula of the left cavernous sinus with venous outflow through the facial vein
• Occlusion of the inferior petrosal sinus

Right ECA and ICA angiography

• Dural AV fistula of the left cavernous sinus with venous outflow through the facial vein

Drainage through the facial vein due to occlusion of the IPS. 

PLAN –A 

• Attempt to access the cavernous sinus through the facial vein resulted in dissection of the vein

Plan-B

• IPS drilling to reach the cavernous sinus

Anatomy of inferior petrosal sinus

• pars nervosa: anteromedial and smaller
• pars vascularis: posterolateral and larger

Anatomy continued  

• The IPS is located in the pars nervosa
• We can either take a view of the jugular foramen to guide us (transoral view with or without the head turned to 10 degrees opposite)
• or we can use a cone beam CT to help us precisely locate the pars nervosa

Material

• 6f short sheath in left ijv
• 5f mpa shaped diagnostic catheter
• 035 hydrophilic guide wire with straight tip
• 017 microcatheter
• 012 microwire
• Detachable coils 10 or 18 system
• +/- liquid embolic agent

Cone beam CT 

• Confirms the location of the wire in the pars nervosa

• After stabilisation of the 5f mpa diagnostic catheter in the pars nervosa, gentle drilling of the IPS with a straight-tipped 035 hydrophilic wire
• The 035 wire is removed under a blank roadmap
• Microwire and microcatheter navigated under a negative roadmap

Coiling of the foot of the SOV and the cavernous sinus

• Left CCA injection shows obliteration of CCF
• Right CCA injection shows obliteration of CCF

After 3 days 

• Resolution of redness of the eye
• Facial swelling and bruising at the facial vein access

15 days follow-up

• No more redness of the eye
• Resolution of subcutaneous hemorrhage

• Recanalisation of the inferior petrous sinus is a useful technique for reaching the cavernous sinus in indirect CCF
• Knowledge of anatomy is vital for plannning and execution
• This case demonstrates that a technique learned in a real case conference can be replicated