Results

A total of ten patients were admitted for recurrent frontal osteomyelitis following initial treatment of covid associated sinonasal mucormycosis. A total of eight patients (80%) were diagnosed with recurrent Mucormycosis by KOH mount of pus from the frontal bone osteomyelitis sent intraoperatively (Fungal elements/broad aseptate hyphae). Nine patients were male (90%) and one female (10%). All the patients (100%) had previously diagnosed sinonasal mucormycosis and previous history of COVID 19 infection. 3 patients (30%) had previously undergone orbital exenteration for CAM.
The average duration of the recurrence was 22 days following the initial treatment Range (10 days to 33 days). The patients presented with frontal headache (100%), frontal bulge (60%), discharging sinus near the medial canthus (10%) (Figure -1), and fever (40%). The diagnostic nasal endoscopy commonly revealed mucosalization of the nasal cavity with mild polypoidal changes in the opened sinuses, there was evidence of pus discharge from the frontal ostium in 30% cases and 40% cases had frontal outflow tract obstruction. Retrospective radiographic review of these patients showed partial to complete opacification frontal sinus in 30% of cases during the initial disease presentation. 30% of patients had undergone debridement of frontal sinus during the initial surgery for CAM.
CECT scan was done to look at the bony status and a complimentary MRI scan was done to look for the soft tissue extent (intraorbital, orbital apex and intracranial extension) and as problem solving tool. The cross sectional imaging revealed extracranial bossing following outer frontal cortex erosion in 30% of cases (Figure -2), bicortical erosion in 30%, bifrontal involvement (20%), Dural involvement (30%), brain parenchymal involvement and prefrontal cortex (20%) case (Table -1).
Open surgical debridement was preferred due to recurrent nature of the disease and for adequate disease clearance. Bifrontal craniotomy with complete debridement of the frontal bone and pericranial flap was done in 7 patients (70%), ipsilateral supraorbital craniotomy was done for 2 patients (20%), intraoperative CSF leak was seen in 2 patients (20%) and was repaired by primary closure with onlay pericranial flap. reconstruction with free flaps and alloplastic materials were not done due to the possibility of seeding in the graft and foreign body reaction. Frank pus was seen in all the patients after exteriorizing the frontal sinus. Bony sequestrum and involucrum was seen along the frontal bone in all the cases (Figure -3). Debridement entailed removal of entire sequestrous bone and a part of involucrum till normal bone was identified.
None of the patients had post operative CSF leak. A closed suction drain was placed in the cavity, removed if drain was less than 25ml. Nasal tamponade packing was removed on postoperatively following 48h.
No patients had neurological deficits following the surgery, 2 patients had local wound collection which needed exploration and evacuation under anaesthesia (Clavein Dindo Grade 3b). All the patients received prophylactic broad spectrum antibiotic coverage and antifungal treatment with Amphotericin B. Amphotericin B was continued till radiological disease clearance. The mean duration of admission was 4 weeks (3 to 6 weeks). All treated patients are currently alive without disease, confirmed by CECT.