At times the surgeon performs the entire procedure in one operating theatre, and then moves to another operating theatre where the patient is already anaesthetised. At other times the surgeon will delegate the commencement or completion of an operation to a junior colleague, trainee or other trained health practitioner. The perceived advantages of utilising two operating theatres simultaneously for the surgeon include minimising downtime between cases, allowing a larger number of procedures to be performed within a given time period and improving overall theatre efficiency. The hospital can also benefit by an increased throughput of cases performed by expert clinical staff.

Overlapping surgery refers to the situation where two procedures overlap in their start and finish times, but where the ‘critical’ portions or those activities which require the skill and expertise of the primary surgeon do not overlap.

Simultaneous or concurrent surgery is when the primary surgeon is responsible for the ‘critical’ portions of two procedures that are happening at the same time.


Critical portions are defined as those portions of a procedure that require the essential technical expertise and judgment of the primary surgeon to achieve the optimal patient outcome that cannot be delegated to another health practitioner. These portions are difficult to define explicitly and definitions of critical portions state that the primary surgeon is the individual best placed to know which portions of an operation are critical. Non-critical portions are elements of the surgery that the primary surgeon does not believe requires their specific technical expertise or judgment and that they are comfortable delegating to an individual/s with less experience. Tasks commonly cited as non-critical include patient positioning, initial incisions and wound closure.

Key issues

Patient safety is the primary focus of all surgical procedures. Performing simultaneous, concurrent or overlapping surgery raises a number of important factors for consideration including:

  • Focusing on the clinical needs of two patients at all times, which may be more challenging when working across multiple theatres

The need for the surgeon to return to a patient to manage an unexpected problem, leaving a second patient whose operation has already commenced, when unexpected difficulties and complications occur during a surgical procedure.

  • Handover of responsibility if parts of a procedure are delegated to another health professional
  • Informing the patient that parts of their operation may be performed by another health professional or offering another alternative should they wish. Ensuring appropriate consent may be more challenging in instances of simultaneous, concurrent or overlapping surgery, and may complicate the process of open disclosure should an adverse event occur

All surgeons must ensure that operation safety practices for patients and theatre staff are adhered to, including completing a surgical safety checklist. It is difficult for a surgeon to contribute, communicate and demonstrate leadership to maximise team performance while working across two theatres simultaneously. Working across two theatres may compromise a surgeon’s ability to participate fully in a surgical safety checklist (i.e. time out at commencement and sign out at the end of a procedure) and may also contribute to an increased risk of adverse events (i.e. site/side error) if they are unable to dedicate their full attention to one patient.

RACS position

  • RACS recommends that every facility offering surgical services should have a policy on overlapping surgery and simultaneous (concurrent) surgery.
  • RACS considers that the practice of overlapping surgery is appropriate as long as the issues of patient safely have been appropriately addressed. RACS recommends that the practice of concurrent surgery is inappropriate.
  • RACS supports the statements on principles published by the American College of Surgeons (ACS) in regard to overlapping and simultaneous (concurrent) surgery which gives the following guidance as to when overlapping surgery is appropriate.

According to the ACS acceptable overlap of two distinct operations by the primary surgeon occurs in two general circumstances:

  1. The first and most common scenario is when the key or critical elements of the first operation have been completed, and there is no reasonable expectation that the primary surgeon will need to return to that operation. In this circumstance, a second operation is started in another operating room while a qualified practitioner performs noncritical components of the first operation for example, wound closure, allowing the primary surgeon to initiate the second operation. In this situation, a qualified practitioner must be physically present in the operating room of the first operation.
  2. The second and less common scenario is when the key or critical elements of the first operation have been completed and the primary surgeon is performing key or critical portions of a second operation in another room. In this scenario, the primary surgeon must assign immediate availability in the first operating room to another surgeon.

Key issues

Should overlapping surgery occur, institutions should develop processes to ensure that patient consent results in a complete understanding by the patient that their surgery will overlap with another patient’s operation. This may involve informing the patient another health practitioner may undertake a portion of their operation. Institutions should develop materials such as frequently asked questions, and educate patients ahead of their operation, giving them enough time to review materials and fully consider their options. Disclosure and informed consent where possible should be timed so that patients can choose whether or not to undergo surgery. If the patient does not agree to the proposed treatment plan, the surgeon should adjust their plans to do all of the operation personally or the surgeon should offer to refer the patient to another practitioner. It is recommended that in instances of overlapping surgery a primary surgeon’s presence and absence from the operating room should be documented in the operative notes and theatre records.

Adverse events

RACS supports the practice of medical professionals engaging in open disclosure with their patients when procedures do not go to plan and support the Australian Commission on Safety and Quality in Health Care (ACSQHC) National Guidelines for Open Disclosure and Medical Council of New Zealand (MCNZ) Disclosure of harm following an adverse event ensuring full informed consent has been obtained prior to any procedure will assist in the open disclosure process.