Surgical oncology

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SURGICAL ONCOLOGY

CASE 1. DORSAL RHINOTOMY Authors: P. Meyer, R. Brühl-Day

DIAGNOSIS

Name: Khala Species: dog

Recommendations for an adequate radiological study of the skull

Sex: female Age: 9 years

The following radiographs of the nasal cavity should be requested to ensure correct evaluation:

Breed: Belgian Shepherd mixed breed

1. Laterolateral (LL). Allows evaluation of the status of the nasal (dorsal) and palatal (ventral) bones. A drawback of this type of radiograph that should be borne in mind is the fact that the nasal cavities and sinuses overlap.

HISTORY AND INITIAL MANAGEMENT

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Khala was brought to the clinic by her owners after experiencing three nosebleeds in 2 weeks. The nosebleeds were unilateral (left nostril). On all three occasions the epistaxis was self-limiting, and stopped after a few minutes. The dog had no history of trauma. Over the 2 weeks in question she experienced isolated episodes of sneezing, which resulted in the elimination of small clots.

The general examination revealed no alterations, and a specific examination of the skull, especially the nasal and oral cavities, revealed no bone deformation, asymmetry, or other abnormalities. No signs of an epiphora were detected. The neurological examination showed no findings of interest. Khala maintained a good appetite and normal daily activity.

Radiographs of the chest, nasal cavity, and paranasal sinuses were requested, as well as a cardiological examination and a complete blood test including a coagulogram.

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Example of a laterolateral radiographic view (a). Real image of the skull as it appears on the radiograph to show the visible structures (b).

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2. Ventrodorsal (VD). With the mouth open, removing the jaw from the radiological field.

This allows correct evaluation of the pneumatisation of the two cavities separately.

Example of a ventrodorsal radiographic view of the nasal cavity with the mouth open (a). Real image (b). Note the normal pneumatisation of both cavities (red arrows) and both frontal sinuses (blue arrows).

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Example of a ventrodorsal radiographic view of the nasal cavity with the mouth closed (a). Real image (b). Unlike the open-mouth radiograph, some information is lost in this position due to the overlap with the mandible.

3. Skyline view of the frontal sinus. Allows evaluation of both frontal sinuses in a single radiological position. In the VD position with the mouth closed, the horizontal branches of the mandible overlap, thus reducing the nasal field that can be evaluated.

To correctly position and perform these radiographs, the patient must be anaesthetised.

Skyline view.

Radiograph showing good pneumatisation of both frontal sinuses.

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SURGICAL ONCOLOGY

Nasal endoscopy (oral and aboral) revealed the presence of a friable haemorrhagic mass, which occupied a large part of the left nasal cavity. The choanae were free of obstruction. The mass was located about 6 cm above the nostrils and extended to the caudal border of the nasal cavity, close to the border with the left choana. No alterations were evident on the right side.

Samples were taken for culture and histopathological diagnosis.

The CT images confirmed the presence of a mass in the left nasal cavity and involvement of the ipsilateral frontal sinus, which, based on tomographic density, appeared to contain only mucus (Figs. 4 and 5).

The results of the blood tests and thoracic radiographs were normal. Radiographs of the nasal cavity and the frontal sinuses showed an increase in radiodensity on the left side (Figs. 1–3).

Rhinoscopy with sampling and a CT scan of the skull were requested as additional tests.

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Figure 1. Ventrodorsal

radiographic view with the mouth open. An increase in radiodensity is evident on the left side.

Figure 4. Computed tomography image. The left

frontal sinus appears to contain mucosal content.

Figure 2. Laterolateral

radiographic view. Note the slight increase in the general radiodensity of the nasal cavity; overlapping frontal sinuses; and radiologically preserved osseous bullae.

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Figure 3. Skyline

Figure 5. Computed tomography image. Note the

radiographic view.

Increased radiodensity of the left frontal sinus is evident.

presence of a mass (probably a tumour) in the left nasal cavity.

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Diagnostic techniques in the nasal cavity Rhinoscopy

Biopsy

Allows exploration of the nasal cavity.

Procedure

Recommendations:

1. Determine the length of the cannula, which should not exceed the medial angle of the eye to avoid damaging the brain.

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Apply general anaesthesia to prevent movement by the patient.

Rhinoscopy can be retrograde, as shown in the illustration (exploration of the nasopharynx and choanae), or anterograde (evaluation of the nasal cavity).

First perform retrograde rhinoscopy. Nostril bleeding reduces visibility.

Irrigate with cold saline to ease the passage of the rhinoscope, remove mucus, and reduce bleeding.

Cover the entrance to the nasopharynx to prevent the entry of fluid into the airways.

2. Introduce the cannula into the nasal cavity via the nostrils. When it reaches and penetrates the tumour, an increase in pressure can be felt. Pull the plunger of the syringe while moving the cannula in various directions within the tumour.

Retrograde rhinoscopy.

3. The sample is deposited on a piece of gauze, where the blood is separated from the tissue. The tissue will be sent to the laboratory for histopathological analysis.

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SURGICAL ONCOLOGY

TREATMENT MEDICAL TREATMENT

Elevation of the periosteum is important, since it will be the first plane to be sutured and it is the tissue plane that will seal the nasal cavity.

Meloxicam (0.1 mg/kg/d) and omeprazole (20 mg/d) were prescribed. Because radiotherapy was not an option, surgical removal of the neoformation via dorsal rhinotomy was proposed.

Nasal cavity tumours, particularly malignant ones, are usually located close to the lamina cribrosa of the ethmoid bone.

Nasal cavity tumours can be malignant or benign. Malignant forms are more common. Generally, they are located in the most aboral portion of the nasal cavity, close to the cribriform plate of the ethmoid bone.

They can be epithelial (e.g. nasal carcinomas) or mesenchymal (e.g. nasal chondrosarcoma) in origin. Of these two tumour types, nasal carcinomas are much more prevalent than chondrosarcomas.

In general, nasal carcinomas can be treated with radiotherapy or surgery. Megavoltage radiotherapy must be performed, as orthovoltage radiotherapy lacks sufficient penetrative capacity.

Figure 6.

Positioning of Khala in preparation for nasal surgery.

SURGERY The patient received general anaesthesia, the surgical field was appropriately prepared, and the animal was correctly positioned for dorsal rhinotomy. The head should be elevated and supported by a band of adhesive tape, which fixes the jaw to prevent movement during the procedure.

Intra-surgical aspiration equipment and sterile wash solutions, previously cooled to the point of ice-flake formation (without fully freezing), should be available.

Cold solutions facilitate haemostasis during the procedure.

After placing surgical drapes around the field, an incision was made in the skin, extending rostrally along the midline from the frontal region, a few centimetres above the orbits, to the union of the bone with the nasal cartilage. Haemostasis was performed by compression and electrocoagulation (Figs. 6–8).

A scalpel was used to cut the periosteum along the dorsal midline. The periosteum was then lifted from the midline to either side using a periosteal elevator. A Gelpi retractor was used to facilitate the manoeuvre and ensure adequate exposure of the operative field (Fig. 9).

Figure 7. Placement of surgical drapes. Note that the nostrils are

exposed so that they can be freely accessed by the surgeon during the procedure.

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Next, the nasal cavity was opened using an oscillating saw. This manoeuvre was completed using a hammer and chisel. While cutting the bone with the saw, sterile physiological solution was instilled to reduce thermal osteonecrosis.

In addition to ensuring closure of the nasal cavity, suturing of the periosteum provides greater support for cutaneous sutures.

Failure to replace the nasal bone would give rise to a depression in the dorsal nasal cavity.

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Figure 8. Skin incision (a, b). Adequate haemostasis is performed by electrocoagulation. The subcutaneous plane is elevated to expose the nasal

bone (c).

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Figure 9. Periosteal incision along the dorsal midline (a) and elevation of the periosteum to expose the nasal bone (b). Elevation of the periosteum is

complete (c).

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SURGICAL ONCOLOGY

The approach includes both nasal cavities because it is necessary to examine both sides and, in addition, this allows bilateral removal of the nasal turbinates, including the nasal septum.

Given that rhinotomy and subsequent nasal curettage do not offer an adequate surgical margin for either carcinoma or chondrosarcoma, it is advisable to leave the nasal cavity empty of elements that could favour recurrence. Therefore, not only diseased tissue is removed, but also remnants of turbinates that appear macroscopically healthy.

Once the nasal bone has been fully cut, it is elevated using an osteotome and a bone hammer (Fig. 12). As soon as the bone rectangle has been extracted, the status of the nasal cavity can be assessed. Following the protocol, we first collect samples with a swab for bacteriological and mycological cultures. Next, both nasal cavities are examined and curettage of the cavities is performed, beginning with the affected side. During this process samples are also selected for histopathology.

Nasal curettage must be performed vigorously and quickly.

This way bleeding, which is usually profuse, is easier to control than if this manoeuvre is performed slowly. The manoeuvre should not be performed roughly, but fast enough to ensure effective control of blood loss. The curettes used should be of the appropriate size for the patient (Figs. 13 and 14).

A 2-cm wide rectangle was resected from the nasal bone, leaving 1 cm on each side of the midline (Figs. 10 and 11).

The limits of the impending curettage are represented by an imaginary line joining both medial ocular angles. Behind this line, within the nasal cavity, is the ethmoid cribriform plate, a structure that must be respected: failure to do so will result in entry into the cranial cavity.

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In cases of tumours, whether carcinomas or chondrosarcomas, the approach should include both nasal cavities and the nasal turbinates should be removed together with the septum, as well as any element that could favour tumour recurrence, since the safety margins provided by rhinotomy and nasal curettage may be insufficient.

Although the diagnosis indicates a unilateral lesion, in cases of cancer both nasal cavities must be approached.

Figure 10. Cutting of the nasal bone using an oscillating saw and irrigation of the bone with physiological solution to avoid thermal osteonecrosis.

Figure 11. Completion of cutting of the nasal

bone.

Figure 12. The cut is completed and the bone is lifted using an osteotome and a bone hammer.

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HEAD AND NECK

Haemostasis is performed concurrently, irrigating and aspirating with sterile, very cold saline slush.

Gauze compression is also applied. Curettage and intranasal tissue removal should be alternated with irrigation, aspiration, and compression. The objective is to leave the nasal cavity completely clear and to ensure that no tissue or clots remain in the nasal passages or nasopharynx. Once the patient is anaesthetised, it is recommended to place a gauze swab in the pharynx as a “seal” to prevent any leakage of fluids into the airway. Although the endotracheal tube cuff acts as a barrier, this increases the level of protection of this pathway.

The turbinates, the nasal septum, and any observable new formation in both nostrils were resected.

The frontal sinus had not been invaded by the tumour, but it contained accumulated fluid, drainage of which was prevented by the tumour. By removing the abnormal tissue, the contents of the frontal sinus began to drain without difficulty. Curettage, washing, and aspiration were continued until it was confirmed that neither tissue nor clots remained in the nasal cavity. A piece of gauze was passed over both nostrils to check for the presence of any remaining tissue (Fig. 14).

Figure 14. A gauze pad is passed through each nostril to remove any remaining tissue and clots (image taken in another patient to demonstrate the technique).

Figure 15.

Completion of curettage. Note that the nasal cavity is empty and clean.

Figure 13.

Aggressive bilateral nasal curettage.

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SURGICAL ONCOLOGY

Next, a cambric gauze bandage soaked in povidone-iodine was placed in the cavity (Fig. 16). It was arranged in a zigzag manner, occupying the entire nasal cavity, from distal to proximal and ventral to dorsal, exiting through a cutaneous incision above the incision used for the surgical approach. The gauze was held in place with a single suture. The gauze should provide some degree of intranasal compression to ensure adequate residual haemostasis. Some surgeons opt not to insert the gauze and report no complications. In our experience, this gauze is best left in place for 48–72 hours.

The objective of packing the nasal cavity with cambric gauze soaked with povidone-iodine is to ensure haemostasis and antisepsis, and to reduce the possibility of subcutaneous emphysema.

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Figure 16. Packing of the nasal cavity with cambric gauze soaked in povidone-iodine (a). The exit point of the bandage is shown at the aboral end of the initial skin incision (b).

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Figure 17. Suture of the periosteum using a simple interrupted suture pattern with 3-0 monofilament nylon.

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Figure 18. Suture of the subcutaneous plane and the skin.

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Khala underwent a second surgical intervention 8.5 months after the first to remove a local recurrence. This procedure allowed her to live for 5 more months free of disease. However, after a second recurrence with significant involvement of the palatine bone, it was decided to euthanise the patient.

Finally, the incision was closed. The periosteal plane was closed using a simple interrupted suture pattern (Fig. 17).

Next, the subcutaneous plane was closed using a continuous U suture, and the skin using a simple interrupted suture pattern (Fig. 18). Monofilament nylon (3-0) was used for all three planes.

It is important to correctly separate the periosteum during the initial surgical approach to ensure that it can be correctly sutured later.

Patients who undergo a rhinotomy with complete curettage of the nasal cavity have an adequate quality of life after surgery.

The patient adequately awoke from anaesthesia and was kept under observation for 24 hours to monitor the effects of postoperative analgesia.

The only possible unwanted effect is sneezing with serous or mucous discharge. This is due to constant irritation caused by the passage of air through the airway without prior heating and filtering of particles by the nasal turbinates and meatus.

COURSE

COMMENTS AND CONCLUSIONS

The patient showed good postoperative evolution. Khala was discharged 24 hours after the intervention.

On the third day, the gauze bandage was removed from the nose (this procedure can cause sneezing, with the expulsion of a clot, but rapidly self-resolves). The patient’s breathing was excellent. The sutures were removed after 7 days.

Khala’s course over the months after surgery was very good. Occasionally, she sneezed producing mild seromucosal discharge.

Rhinotomy is an alternative approach for the treatment of intranasal tumours if adequate radiotherapy is not available. Collateral effects or complications include incoercible bleeding during or immediately after the intervention. Another possible complication is subcutaneous emphysema (localised to the head or generalised).

The former is treated with whole blood transfusions to provide clotting factors and platelets, as well as red blood cells. This occurs in 1 % of patients.

Subcutaneous emphysema is seen in approximately 5 % of dogs and more than 50 % of cats. It is usually self-limiting and is caused by leakage of air between the open nasal cavity and the skin. For this reason, a temporary drain is generally prescribed to ventilate the nasal cavity. When the healing process is complete and the defect is closed, the trapped air is absorbed within a few days.

Histopathological diagnosis confirmed the presence of a low-grade nasal carcinoma. The patient was referred to an oncologist, who indicated adjuvant treatment with meloxicam.

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SURGICAL ONCOLOGY

CASE 2. ROSTRAL MAXILLECTOMY Authors: M. E. Martínez, P. Meyer, R. Brühl-Day

Name: Felipe Species: dog Sex: male Age: 10 years Breed: mixed breed

Figure 1. The patient was seen for a diagnosed rostral

maxillary tumour.

CLINICAL HISTORY AND INITIAL MANAGEMENT

PREOPERATIVE STUDY Presurgical tests performed: ■ Complete blood count.

■ Blood chemistry, with coagulogram.

■ Electrocardiogram and echocardiogram.

■ Radiological study: plain radiographs with ventrodorsal (VD), laterolateral (LL), and oblique views of the skull. These radiographs make it possible to establish the extent of the neoformation and of bone involvement, if present.

■ Computed tomography (CT) may also be helpful, if the necessary equipment is available.

The patient arrived at the clinic with a rostral maxillary tumour that had been detected 15 days earlier.

The clinical examination revealed the presence of a mass in the central rostral region of the maxilla, extending in the aboral (caudal) direction, almost reaching the first premolars (PM) (Fig. 1). Although feeding was somewhat difficult for the patient, he did not show excessive pain and continued to eat a soft diet.

SURGICAL PROCEDURE

TREATMENT

Maxillectomy is considered a clean-contaminated surgery.

Nonetheless, aseptic technique is respected. The oral mucosa is washed with chlorhexidine solution diluted 1:39 or using dental chlorhexidine solution.

Figure 3 shows the appearance of the tumour.

It was decided to remove the tumour by maxillectomy and to insert a tension band using the cantilever suture technique in order to keep the rostral portion of the muzzle elevated, thereby preventing drooping as a consequence of partial resection of the maxilla (Fig. 2).

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Figure 2. Cantilever

technique. Schematic depicting the surgical procedure (a).

Representation of the structural purpose of the suture supporting the nose, like a cantilever (b).

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Figure 3. Presentation and appearance of the tumour (a). Note the involvement of the incisors (b).

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SURGICAL ONCOLOGY

Monofilament nylon suture was used to attach the endotracheal tube to the labial commissure, thereby fulfilling two functions: (i) immobilising the endotracheal tube to avoid accidental displacement; and (ii) keeping it away from the surgical field so that it does not interfere with tumour resection (Fig. 4).

After placing the surgical drapes, a gauze swab was placed in the pharynx to prevent blood or physiological solution from entering the airways. Simultaneously, the nasopharynx was occluded so that bleeding caused during the maxillary ostectomy did not pass into the airways.

A mouth gag, anchored to the last PM, should be put in place taking care not to open it fully, as this can cause pain in the immediate postoperative period (Fig. 5).

The surgical approach began with a dorsal incision in the mucosa below the upper lip (Fig. 6). The mucosa of the hard palate was raised and reflected off the underlying bone to prepare the area for osteotomy of the maxilla. In this case, the safety margin consisted of resection up to the second premolar (Fig. 7).

Once the bone to be resected was prepared, osteotomy was performed using an oscillating saw, irrigating with abundant physiological solution during section of the bone (Fig. 8).

Figure 4. Note the position of the endotracheal tube, which is sutured

Figure 5. Gauze is placed in the pharynx to prevent the entry of blood

to the labial commissure.

or physiological solution during ostectomy of the maxilla.

Figure 6. Dorsal incision below the upper lip to separate the maxilla

Figure 7. Separation of the mucosa of the hard palate from the bone.

from the skin and subcutaneous tissue.

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