Surgical Tools

Documentation

Surgical tools for rodents comprise all the instruments required for performing surgical techniques in animal laboratories. Different survival and non-survival rodent surgeries include laparotomy, thoracotomy, spinal transection, bone replacement, craniotomy, and stereotaxic surgeries for implanting guide cannulas or microdialysis probes. The precise utilization of surgical tools requires planning and execution. The researcher/surgeon must practice the skill with patience to be successful.

High-quality surgical tools are durable, corrosion-free, and resistant to physical and chemical changes. Conduct Science offers various surgical tools for basic, general, ophthalmic, stereotaxic, and neurological surgeries. These instruments are made of excellent quality stainless steel and are available at economical prices. They can also be designed according to your experimental needs.

Surgical tools for beginners can be divided into four major categories:

Cutting and Dissecting
Clamping and Occluding
Grasping and Holding
Retracting and Exposing

Cutting and Dissecting Tools

Cutting and dissecting instruments are mainly used for tissue incision or dissection. Their main purpose is to remove unnecessary layers or tissues during surgery. These surgical instruments mainly include scalpels, scissors (like straight and curved mayo scissors and Metzenbaum scissors), dissectors, amputation knives, saws, etc.

Scalpel handles are used to hold blades during anatomical surgeries and dissections. These blades and handles are available in different sizes, and the experimenter must choose the correct size according to individual requirements. For instance, the #7 handle with a #15 blade is used to cut deep tissues, whereas the #3 handle with a #10 blade is used to cut superficial layers. Similarly, a skinning knife with handle #4 and blade #20 is used for incising the skin. Straight mayo scissors, also known as suture scissors, are used to cut sutures. In contrast, curved mayo scissors available in regular and long sizes are suitable for dissecting heavy tissues like fascia muscles, breasts, and uterus. Metzenbaum scissors are appropriate for delicate tissue dissection.

Clamping and Occluding Tools

Clamping and occluding instruments are used to hold or compress blood vessels to achieve hemostasis or prevent spillage. They include hemostats, Kelly, mosquito, etc.

Hemostats are used in rodent surgeries to maintain hemostasis by clamping the ends of punctured or cut vessels and for “preventive hemostasis” before cutting the vessel. They may have straight or curved jaws. Mosquito forceps are fine artery forceps used to clamp smaller blood vessels, whereas a Kelly is used for larger vessels and tissues. Publishers have two closed finger rings, and they clamp deeper blood vessels. Similarly, a right angle, also known as a mixer, is used to clamp vessels that are hard to reach and for suturing behind or around the vessel. Additionally, a hemoclip applier with hemoclips is used to clip the vessels so that they remain occluded during surgery.

Grasping and Holding Tools

Grasping and holding instruments are used to grasp tissues. These instruments aid the scalpels and are usually held in the non-dominant hand. Any instrument that is used for grasping is termed a forceps. Forceps may be fine or heavy, toothed, or smooth, all depending on their utility. These forceps may have a tweezer-like or scissor-like appearance. They are used to grasp the tissues while dissecting. Grasping forceps includes an Allis, a Babcock, a Kocher, a Foerster sponge, and even a dissector.

Adson or Gillie forceps are used to hold delicate tissues, often utilized for final skin closure. They usually have serrated tips. Allis forceps, on the other hand, are toothed and ratcheted. They are used to grasp tissues requiring a firm grip, such as the quadriceps tendon during lipoma capsule excision repair.

Kocher forceps are heavy ratcheted forceps with grooves on the blades, used for grasping heavy tissues or fascia. Another example of heavy but non-toothed forceps is Babcock forceps used to hold delicate tissues like the ovary or fallopian tube. However, they might slip and not have a firm grip over tissues. Mayo-Hager forceps are needle-holding forceps and have a ratcheted scissors-like appearance.

Retracting and Exposing Tools

Retractors are used to hold organs and tissues to improve the exposure of the surgical site and make it visible. Retractors can be handheld or self-retaining. Retractor wires or tips can achieve retraction in rodents. Retractor wires lock into the fixator jaws at desired elevation and facilitate rotational adjustment along the wire length. Retractor tips can be used in conjunction with wires to achieve dynamic retraction. Wire retractors are the simplest form of retractors used for rodents. The most common types of retractors include Belfour, Gelpi, Barraquer, and wire retractors.

Pre-Operative Care

Surgical Area Preparation

Choose an uncluttered, calm working area away from laboratory traffic, ventilators, or open ducts.
Utilize a separate room for aseptic procedures.
Disinfect the work surface and apply a clean drape over where the surgery is to be performed.
Ensure the sterility of the workspace, surgical tools, and surroundings.

Animal Preparation

Anesthetize the animal with isoflurane and confirm sedation by pinch withdrawal reflex.
Constantly monitor the subject’s body temperature via a homeothermic monitoring system and use a heating pad to prevent perioperative hypothermia.
Administer appropriate presurgical analgesic before anesthesia induction.
Apply ophthalmic ointment to prevent the eyes from drying out.
Depilate the hair at the surgical site using a clipper blade.
Prepare the surgical site aseptically. Clean the site with povidone-iodine or chlorhexidine solution.
Apply 70% alcohol or sterile saline on gauze and use it to wipe away excess chlorhexidine.
Avoid excessive wetting of surgical sites with the products mentioned above, as it can exacerbate hypothermia.
Cover the rodent with a sterile drape or towels to minimize skin trauma (Miwa and Sladky, 2016).

Post-Operative Care

Maintain the subject’s body temperature during post-operative recovery. Recovery in an incubator might be preferred.
Administer post-surgical analgesics, including opioids and non-steroidal anti-inflammatory agents (Smith et al., 2020).

Sterilization of the Surgical Tools

A reusable surgical instrument should be easy to sterilize. Aseptic techniques are indispensable for limiting microbial contamination in survival surgeries that otherwise leads to suppuration or infection. Therefore, the surgeon must ensure asepsis throughout the surgery. In this regard, the sterilization of surgical instruments, supplies, and implanted materials is requisite. The instruments can be sterilized using any of the underlying methods.

Method

Comments

Autoclave

Steam sterilization is performed by autoclaving the surgical equipment at 121oC for 15 minutes or at 131oC for 3 minutes.

Dry Heat

Heat the tools at 250oC for 15 seconds in a hot bead sterilizer. The instruments must be cleaned and cooled down before use.

Ethylene Oxide

This gas serves as a good sterilant when applied at 30% relative humidity in a chamber placed in a fume hood. Do not forget to aerate the tools for a long time after ethylene oxide exposure because it is irritating to the tissues. It can also be harmful to the researchers.

Chemical Sterilant

Chemical sterilants include formaldehyde, hydrogen peroxide, chlorine dioxide, etc. the effectiveness of these chemicals depends on their contact time with the instruments, composition, age of the solution, and removal of organic material from the tools.

Summary

Surgical tools for rodents comprise all the instruments required for performing surgical techniques in animal laboratories.
Cutting and dissecting instruments are mainly used for tissue incision or dissection. These surgical instruments mainly include scalpels, scissors, dissectors, amputation knives, and saws, etc.
Clamping and occluding instruments are used to hold or compress blood vessels to achieve hemostasis or prevent spillage. They include hemostats, Kelly, mosquito, etc.
Grasping and holding instruments are used to grasp tissues. They include an Allis, a Babcock, a Kocher, a Foerster sponge trick, and even a dissector.
Retractors are used to hold organs and tissues to improve the exposure of the surgical site and make it visible. Retractors can be handheld or self-retaining.
Maintenance of asepsis throughout the surgery is requisite for successful survival surgeries of rodents.

References

Smith, A. C., & Swindle, M. M. (2020). Surgical facilities, perioperative care, anesthesia, and surgical techniques. In Animal Models in orthopedic research (pp. 59-69). CRC Press.
Miwa, Y., & Sladky, K. K. (2016). Small mammals: common surgical procedures of rodents, ferrets, hedgehogs, and sugar gliders. The veterinary clinics of North America. Exotic animal practice, 19(1), 205.