Veterinary Surgical Oncology. Группа авторов

a Jamshidi needle are only 82% accurate (Sabattini et al. 2017), an earlier study found that in approximately 92% of cases, a correct diagnosis of tumor versus nontumor is achieved when using a Jamshidi needle (Powers et al. 1988).

Instrumentation includes a #11 blade and a Jamshidi needle (Figure 1.5). The surgical site is clipped free of fur, and the patient is prepared with aseptic technique and draped. A 1–2 mm stab incision is made over the bony lesion. The Jamshidi needle is introduced into the stab incision and pressed onto the bony lesion. The stylet is then removed from the needle, and the needle is twisted until the cis cortex is penetrated. The Jamshidi needle is rocked back and forth to loosen the sample and then removed. The stylet is reintroduced into the needle in the opposite direction of the initial location. As the stylet is moved through the Jamshidi needle, the biopsy will be ejected from the base of the Jamshidi needle.

For lesions that are large enough to be palpated, image guidance is not necessary. However, for small nonpalpable lesions, image guidance is recommended to document that the biopsy samples were indeed acquired from the lesion, preferably the center of the bone lesion. Fluoroscopy and radiography can be used and sometimes even CT‐guidance can be helpful.

       Lymph Node Biopsy

      Treatment and biopsy of lymph nodes in neoplastic disease remain controversial (Gilson 1995). It is demonstrated that lymph node size (Langenbach et al. 2001; Williams and Packer 2003) and needle aspirates are not great at detecting metastases (Ku et al. 2017; Fournier et al. 2018). Removing a lymph node or performing an incisional biopsy of a lymph node can aid in staging the patient and assist in the determination of prognosis or treatment options. The surgical oncologist should have a thorough knowledge of the anatomic location of the probable draining lymph node for a mass in a particular location. Alternatively, sentinel lymph node detection techniques such as lymphography and scintigraphy can be used (see Chapter 14). The excisional biopsy of superficial lymph nodes such as the mandibular, superficial cervical (prescapular), axillary, inguinal, or popliteal lymph nodes is described below. For removal of lymph nodes within the thorax or abdomen, an exploration of that body cavity is performed and the lymph nodes are removed by careful dissection and maintenance of hemostasis.

      Instrumentation includes a #10 or #15 blade, Metzenbaum scissors, forceps, Mayo scissors, and suture. The surgical site is clipped free of fur, and the patient is prepared with aseptic technique and draped. An incision slightly larger than the palpable lymph node is made parallel to the axis of the lymph node. The superficial tissue overlying the lymph node is bluntly and sharply dissected. The lymph node capsule is then grasped with the forceps and blunt and/or sharp dissection is performed around the lymph node to free it from the surrounding tissue. Vessels that are encountered may need to be ligated. The lymph node is then removed, and the subcutaneous tissue and skin are closed. Many “lymph nodes” are actually lymphocenters. The implication is that multiple lymph nodes can be present in one location, for example, the mandibular lymphocenter often has two to three lymph nodes.

Figure 1.5 (a) Jamshidi needle (left) with the two stylets (middle and right). The stylet in the middle is used to approach the bone. The stylet to the right is used to remove the sample from the needle after being acquired. (b) The end of the needle is tapered, helping to keep the sample in the needle when the needle is removed from the bone. (c) To remove the sample from the needle, the stylet is introduced through the tip of the needle and the sample is pushed to exit the base at the handle. In some instances, there is too much resistance to push the sample out of the handle end, in which case the first stylet is used to push the sample out through the tip. It is not ideal because in theory the sample can suffer some damage going through the narrowed end, but sometimes it is necessary.

       Endoscopic Biopsy

      Esophagoscopy, gastroscopy, duodenoscopy, and colonoscopy are routinely performed in veterinary medicine as minimally invasive techniques to attain biopsies of the gastrointestinal tract. Biopsies attained during these procedures are generally smaller than what can be achieved with an open procedure; however, the biopsies are often diagnostic, and the morbidity associated with these procedures is reduced over open procedures (Magne 1995; Moore 2003).

      Laparoscopy and thoracoscopy are still relatively underutilized modalities, but successful procurement of kidney, bladder, liver, spleen, adrenal gland, pancreas, stomach, intestine, and lung biopsies have been described by the use of these procedures (Rawlings et al. 2002; Lansdowne et al. 2005; Vaden 2005; Barnes et al. 2006). Case selection is essential when considering these minimally invasive alternatives, as cases that have excessively large tumors or other potential contraindications should undergo an open procedure.

      Laparoscopy and thoracoscopy may have a role in the staging of veterinary patients as the use of these techniques increases. In cases where lymph node evaluation and biopsy would assist in predicting outcome or determining treatment, these procedures could be performed by minimally invasive techniques (Fagotti et al. 2007; Steffey et al. 2015; Lim et al. 2017).

      Surgical Considerations for Curative‐Intent Surgery

      Certain surgical technical principles will improve the chance of success and minimize the risk of local or distant seeding of tumor cells. The tumor should be draped off from the rest of the surgical field. Surgeons should attempt to not contact ulcerated or open areas of tumor with gloves or instruments. Sharp dissection is preferred over blunt dissection, when possible, as this will decrease the likelihood of leaving neoplastic cells within the patient and decrease the risk of straying from the preestablished margin. Tension on skin closures should be avoided whenever possible, especially in cases that have undergone radiotherapy. Proper knowledge of tension‐relieving techniques such as tension‐relieving sutures and flaps can assist in closure (Soderstrom and Gilson 1995; Aiken 2003); however, tension‐relieving skin incisions are contraindicated after removal of a neoplasm. If an indwelling drain is deemed necessary in a tumor resection site, the drain should be located in an area that can be resected during a subsequent surgery or in an area that will not compromise radiation therapy and can easily be included in the radiation field. Lastly, control of hemostasis and prevention of seroma or abscess development due to dead space is encouraged. Seromas or hematomas following an incomplete resection allow tumor cells to gain access to areas beyond the surgical field as these fluids may be widely dispersed throughout the subcutaneous space during movement.

      To decrease the risk of recurrence after tumor resection, there are several techniques that the surgeon should practice. For tumors that have been previously biopsied or for which a drain has been placed, the biopsy tract and/or drain hole need to be removed en bloc with the tumor. Similarly, adhesions should be removed en bloc with the tumor, when possible. Leaving any of these can result in an increased risk of tumor recurrence. Additionally, when establishing a margin during surgical dissection, this margin must be maintained around the periphery of the tumor down to the deep margin. Straying from this may result in an incomplete resection. Similarly, the pseudocapsule present around a tumor should not be penetrated, as this pseudocapsule is constructed of a compressed layer of neoplastic cells (Soderstrom and Gilson 1995). Seeding of these cells will likely result in recurrence, and healing may be inhibited. Lastly, it is important that a new set of instruments, gloves, and possibly drapes be utilized for closure of a wound created by tumor removal or reconstruction of a wound. This principle applies to the removal of subsequent