Operational Bulletin 423 - May 24, 2012
Summary
Effective June 1st, 2012, officers can request that an applicant's medical file be reassessed by a Medical Officer (MOF) or a Health Branch (HB) delegated staff for the issuance of a new medical certificate. The process applies to cases where a final decision of an officer is pending only due to the expiration of a medical certificate or when the validity of the medical certificate is about to expire and the applicant is unable to land before it expires. This process is limited to applicants who had a routine immigration medical examination (IME) done by a panel physician within the last 15 months in or outside Canada. The new medical certificate issued will be valid for 12 months.
So essentially their left hand applies to their right hand for an extension. Don't think it ever gets outside of the govnment offices.
MM_Sask