**2. General characteristics of intraoperative ultrasound**

#### **2.1 Intraoperative ultrasound in open surgery**

Intraoperative ultrasonography (IOUS), according to Machi and coauthors [1] can provide a wide range of diagnostic information that would otherwise be unavailable or unavailable, as well as a guide or help with various surgical procedures in real time. With the technical development of the proper equipment, IOUS is currently used in a wide variety of surgical interventions, such as hepato-biliary, pancreatic, endocrine, cardiovascular, and neurologic surgeries. Among its numerous advantages, we underline safety, quickness, accuracy, and versatility. Therefore, IOUS is a valuable technique that surgeons are recommended to master to improve intraoperative decision-making. Furthermore increasing the attention for details, ultrasound Doppler allows the user to visualize blood flow and can assess the blood supply in and near the area of interest, thus avoiding injury to important vessels during dissection, as found by Vapenstad and collab [2]. Various intraoperative transducers are available for use, as mentioned by Marcal and team [3] in abdominal surgery: Linear array, curvilinear array, and phased array IOUS transducers are made available by different vendors. One of the most important criteria is that the probe fits snugly into the surgical incision and can be easily maneuvered in a narrow operative space. Higher-frequency transducers, in comparison with lower frequency transducers, can produce higher-resolution images.

Due to the faster attenuation, as the wave passes through the tissue, high-frequency echography waves have a mild tissue penetration. Moreover, from a didactic perspective, the operating room is a place in which the surgeon (more than in the case of other specialties) has a favorable environment to learn operative ultrasound use and interpretation, since the surgeon is already familiar with the anatomical structures that have to be examined during the procedure.

#### **2.2 Laparoscopic ultrasound**

Laparoscopic ultrasound is a relatively new method in point of surgical sonography, whose arrival can be attributed to the need for the development of specialized transducers that could fit through conventional laparoscopic trocars. The quality, reliability, and ease of use of such units have evolved quickly, so that laparoscopic ultrasonography became routine. One of the advantages of this procedure is that it helps the surgeon to peer into the tissues being operated on, compensating for the inability to palpate those tissues physically.

#### *Intraoperative Ultrasound in Colorectal Surgery DOI: http://dx.doi.org/10.5772/intechopen.100411*

As a result, not only did it help to replicate open surgery, but it also helped to improve existing laparoscopic surgical techniques. The monitoring of the tips of ultrasound (US) laparoscopes presents several particular challenges.

Instead of a camera, an ultrasound laparoscope's tip has an ultrasound array.

As a result, computer vision tracking methods cannot be used to detect the tip using the image from the laparoscope. The control levers on the laparoscope handle can be used to adjust the tip of the probe.

In contrast to endoscopes, which are rigid throughout, and the tip's pose can be calculated solely by tracking the handle, ultrasound laparoscopes require an additional sensor installed on the tip to obtain the pose, as defined in Chinmay's work [4].

An ultrasound array is located at the tip of the considered ultrasound laparoscope.

The probe's tip is movable, and the surgeon operating the laparoscope may use the control levers to adjust the tip's trajectory even further.

These levers are attached to the laparoscope's tip.

The movement of the laparoscope tip is usually regulated by two levers.

The laparoscope tip may be relocated in a hemispheric space inside the patient's body using them (**Figure 2**).

Alecu and coauthors [5] came to the following conclusions in a report on the efficiency of visualization and the general benefits of laparoscopic ultrasonography in abdominal surgery:


#### **Figure 2.**

*(a-c) A laparoscopic probe has a needle biopsy enhancement (a, above) and two lower images (b, c) showing the flexibility of the tip of the probe.*

**Figure 3.** *A surgical robot and the schematic approach to the colorectal area.*
