Image-guided navigation during abdominal surgery

Identification and sparing of the iliac vessels and ureters during abdominal
cancer surgery leads to decreased morbidity rates.

Primary Objective:
Feasibility and safety of an in-house developed electromagnetic navigation
system during abdominal surgery.
Secondary Objectives:
Evaluation of the accuracy of the system. Evaluation of possible improvements
of the navigation hardware and software, especially the handling in preparation
towards and during surgery.

An observational registration study.

Participation in the study will not involve additional visits to the hospital
for the included patients. Informed consent will be obtained during the
pre-operative outpatient clinic appointment or upon admission to the hospital
at least one day before operation.
One day before surgery, when patients are already admitted to the hospital, a
contrast-enhanced CT-scan of the abdomen is performed. During the scan three
removable electromagnetic reference-marker patches are placed on the skin at
superficial bony structures of the pelvis, such as the anterior superior iliac
spine. The CT scan will be used to create a three-dimensional anatomical
reconstructions of the organs at risk within the pelvis. Before surgery, the
reference-markers will be positioned at the same locations. The
reference-markers will be used during surgery to correlate the CT scan to the
actual patient position. An intra-operative CT scan will be acquired to
validate and improve the reference marker registration. During surgery, the
iliac vessels and ureters will be identified using the guidance of a blunt tip
probe of the navigation system. Total time of the proposed measurements will
take no longer than 20 minutes. It is highly unlikely that the iliac vessels
and ureters will be damaged during this procedure, since the navigation
procedure is aimed at sparing these structures. When the abdominal tumour is
rigid, e.g. sacral invasion, or when pathological lymph nodes are present
outside the standard total mesorectal excision region, the navigation system
will be used to localize these structures too. This is a pilot study to
evaluate the overall performance of the surgical navigation system during
abdominal surgery, without impact on the surgical procedure itself. However, if
available, the appointed locations of malignant tissue based on navigation will
be cross-correlated with pathology. The eventual goal of this project is to
implement the navigation system to reduce the risk of damage to healthy
structures and more radical abdominal surgery.