Effect of Chitodex Gel in Tympanoplasty Surgery

The general purpose of this study is to compare Chitosan-dextran (Chitodex) gel versus current standard of care, Gelfoam, as a middle ear (ME) and external auditory canal (EAC) packing agent as part of tympanoplasty procedures to close tympanic membrane perforations (TMP), or ossiculoplasty due to ossicular chain disruption and its sequelae, or mastoidectomy for Chromin Otitis Media (COM) or its sequelae eg cholesteatoma.

The investigators aim to compare the success rates of middle ear surgery between the two products. The ultimate goal is to identify the ME packing agent-of-choice to ensure TMP closure as well as minimal inflammation of the middle ear mucosa. The most critical measure of success during tympanoplasty surgery is the closure of a chronic, pre-existing TMP. As such, the primary outcome will be a measure of tympanic membrane closure. This is performed under direct vision during routine post-operative surveillance via the use of either a hand-held otoscope or an operating otologic microscope. The investigators will perform this check at 4 distinct time-points: 2 and 6 weeks post-op, 3 months post-op and 6 months post-op.

Chitosan-dextran gel is packaged within a syringe and has a cannula attached, much like the Gelfoam syringe system. Approx 3-5mL of product is applied during the surgery. Approx 2mL into the middle ear, as a support material for the graft. After graft suturing is complete, another 3mL (approx) is applied into the external ear canal as a packing agent. This is the same procedure as Gelfoam is currently used for this purpose.

The surgeon will administer the gel during the surgery as they would with the standard of care Gelfoam. The product comes in a sterile kit to be opened by Scrub Nurse.

Fidelity of the interventions is measured in several ways by the surgeon at the end of the operation. A good seal for the graft is always assessed for by the surgeon prior to completing any tympanoplasty. This is determined via any evidence of air escape from the middle ear when palpating the tympanic membrane and graft at the end of the procedure. A good seal indicates a well-positioned graft. The surgeon's operative notes will indicate this. The investigators will also obtain endoscopic images and videos at the end of procedure to assess positioning of the graft.

Inclusion criteria

• Individuals who have otoscopic evidence of tympanic membrane perforation that is also confirmed by tympanometry (Defined as a Type B tympanogram, with elevated EAC volume) AND

• The TM perforation is associated with at least 15dB of conductive hearing loss on the affected side AND
• Are indicated to undergo closure of the perforation via tympanoplasty surgery
• OR Individuals who are indicated for ossiculoplasty due to ossicular chain disruption and its sequelae
• OR Individuals who are indicated for mastoidectomy for COM or its sequelae eg cholesteatoma
• Demonstrate healthy, dry middle ear mucosal cavities at time of surgery AND
• Are 18 years of age or over AND
• Are able to give written informed consent AND
• Are committed to returning for post-operative assessments at 2 and 6 weeks post-op, 3-, and 6- months post-op

Exclusion criteria

• Operative ear is the better or only hearing ear
• The ear has evidence of cholesteatoma or other middle ear tumour during otoscopic examination
• dysfunction during otoscopic and tympanometric examination
• Known allergy to shellfish or ciprofloxacin antibiotics
• Pregnant or breastfeeding
• Hepatitis, HIV or any blood disorders
• COVID-19 positive patients
• Contra-indications for MRI