Chapter 45 - Pharynx part II SURGERY Flashcards
What is the primary surgical option for treating DDSP according to recent evidence?
Laryngeal tie-forward combined with partial bilateral resection of the thyrohyoideus muscle.
What surgical procedure is deemed ineffective for DDSP treatment?
Tension and thermal palatoplasty.
Which structural abnormalities should be addressed surgically in the nasopharynx?
Abnormalities such as epiglottitis, cysts, and granulomas.
What is the maximum length of soft palate that can be resected during staphylectomy without compromising the oropharynx-nasopharynx seal?
0.75 cm
How long does the laryngotomy site take to heal postoperatively?
Approximately 3 weeks.
What is the position of the horse during staphylectomy?
Dorsal recumbency with head and neck extended.
What incision length is typical for a laryngotomy during staphylectomy?
10 to 12 cm
What type of suture material is used to reappose the cricothyroid membrane?
No. 0 polyglactin 910
What is the purpose of a laryngeal tie-forward surgery?
To eliminate the gap between the epiglottis and the soft palate.
Staphylectomy should be reserved to resect what?
a granuloma or cyst from the caudal free edge of the soft palate or for treatment of permanent DDSP as an additional step following a laryngeal tie-forward procedure.
Describe the staphylectomy
A 10- to 12-cm (4- to 5-in) skin incision is made along the midline, centered over the cricothyroid space. The sternohyoideus muscles are divided bluntly using curved Mayo or Metzenbaum scissors. A self-retaining retractor, such as a Weitlaner or a Hobday, is placed between the separated sternohyoideus muscles, exposing the cricothyroid membrane. The cricothyroid membrane is sharply incised (along with the underlying laryngeal mucosa) with a scalpel along the midline, from the cricoid cartilage to the junction of the thyroid cartilages (Figure 45-22). A small blood vessel is usually also transected at the level of the caudal two thirds of the membrane. The vessel is ligated or cauterized. The self-retaining retractor is subsequently placed within the cricothyroid space. The caudal free margin of the soft palate rostral to the incision is identified. If the horse was intubated nasotracheally, the soft palate may not be displaced, and the caudal edge of the soft palate may have to be freed from beneath the epiglottis using a pair of sponge forceps. If the horse was intubated orally, the palate will be displaced and the endotracheal tube should be retracted at this time.
Id cyst and transect with satinsky thoracic scissors
Can be left to heal by 2nd intention or suture
Figure 45-22. Schematic showing view of the ventral cervical area of a horse in dorsal recumbency and illustrating the landmarks for a laryngotomy. The sternohyoideus muscles have been bluntly separated on the ventral midline, and the cricothyroid membrane and underlying laryngeal mucosa is sharply incised from the cricoid rostrally to the thyroid cartilage. CT, Cricothyroid muscle overlying the ventral aspect of the cricoid cartilage; T, tracheal ring.
In the treatment of permanent DDSP , the gap between the dorsal aspect of the epiglottis and the overlying soft palate is eliminated by the
tie-forward surgery (Figure 45-23, A and B). When needed, a laser-assisted staphylectomy follows the tie-forward procedure to permit the epiglottis to be repositioned dorsal to the soft palate after a swallow
Figure 45-23. Lateral radiographic projection of a 4-year-old Thoroughbred gelding with a permanent displacement of the soft palate prior to surgery (A) and after laryngeal tie-forward (B). Note the air in the mouth and the ventral position of epiglottis prior to surgery. After surgery (B) the epiglottis is bulging (arrow) against the soft palate. Linear white densities are 5-cm (2-in) pins used to measure magnification of radiographs
Figure 45-24. Intraoperative laser staphylectomy in a 4-year-old Thoroughbred colt with permanent DDSP after first having performed a laryngeal tie-forward. (A) The intended line of resection has been marked using a diode laser. (B) The left edge of the soft palate is grasped with a laryngeal forceps and the marked line of resection is cut.
Complications of staphylectomy
dysphagic, leading to signs of aspiration that include coughing, expulsion of feed material through the nose, and
pneumonia.
What postoperative care is recommended for horses following staphylectomy?
Muzzle for several hours and antibiotics for 7 days.
Standard myectomy what is it?
partial removal of sternohyoideus and sternothyroideus, with or without omohyoideus resection) is performed to reduce caudad retraction of the larynx
Is it performed GA or Standing the standard myectomy ?
sternothyroideus and sternohyoideus muscles are removed with the horse standing as the procedure was first described. If the plan is to ALSO REMOVE a section of omohyoideus muscle, the procedure should be performed under GA with the horse positioned in dorsal recumbency and the head and neck extended
A
10-cm ventral midline incision is made through the skin, continuing through the cutaneus colli muscles. The paired sternohyoideus muscles are identified. Using curved forceps, the sternohyoideus and sternothyroideus muscles are undermined. The sternothyroideus muscle is positioned caudolateral to the sternohyoideus muscle at this level of the neck. The muscles are elevated through the incision and clamped with a Rochester-Carmalt forceps at the proximal and distal extent of the incision. The muscle bellies are sharply transected between the forceps, removing a 6- to 8-cm-long section of muscle. The muscle tissue that was removed should be inspected to ensure that sections of both sternohyoid muscles and the smaller sternothyroid muscles were indeed removed. Previously, the omohyoideus muscle was sometimes removed; however, significant dead space was created, leading to a higher rate of incisional complications, and therefore resection of the omohyoideus is no longer recommended
What should be monitored postoperatively to assess success of the laryngeal tie-forward?
Endoscopic positioning of the epiglottis relative to the soft palate.
What is the common approach to minimize complications when performing a myectomy?
Avoiding resection of the omohyoideus muscle.
How long post-surgery can training typically resume after a standard myectomy?
2 weeks after surgery.
What are the common complications associated with standard myectomy?
Incisional seromas and infections.
In the end of standard myectomy what should you do?
The subcutaneous and skin layers are closed routinely. If a Penrose drain is used, it is placed alongside the ventral aspect of the trachea and tunneled through a stab incision distal to the surgical incision. A firm bandage is applied around the neck and may be removed along with the drain 24 hours later.
What is the postop for standard myectomy and minimally invasive myectomy?
NSAI Ds can be continued for 3 days, and antibiotics should be continued for 5 to 7 days. The horse is kept in a stall with daily hand walking for 2 weeks. Training can be resumed 2 weeks after surgery, when the sutures are removed. Complications are usually related to the incision and include incisional seromas and infections.
What is the reported success rate for standard myectomy in treating DDSP?
58% to 71%.
What is the common approach to minimize complications when performing a myectomy?
Avoiding resection of the omohyoideus muscle.
How long post-surgery can training typically resume after a standard myectomy?
2 weeks after surgery.
What are the common complications associated with standard myectomy?
Incisional seromas and infections.
What does minimally invasive myectomy involve?
Partial sternothyroidectomy or the Llewellyn procedure.
What is the length of incision typically made for minimally invasive myectomy?
5 to 7 cm.
What anatomical structure must be avoided during the transection of the sternothyroideus tendon?
The caudal laryngeal artery.
Describe surgical procedure of minimally invasive myectomy
Partial sternothyroideus myectomy and tenectomy is performed with the horse under general anesthesia.70 A 5- to 7-cm ventral midline skin incision is made centered on the cricoid cartilage. The subcutaneous tissue is incised, and the sternohyoideus muscles are divided bluntly using curved Mayo or Metzenbaum scissors. The blunt dissection is continued dorsal to the sternohyoideus muscle, exposing the caudolateral border of the thyroid cartilage. The tendon of insertion of the sternothyroideus muscle at the thyroid cartilage is identified, undermined, and elevated. The tendon is transected 1 cm caudal to its attachment to avoid
the caudal laryngeal artery, taking care to avoid damaging the cricothyroid muscle.Using one index finger, the sternothyroideus muscle is freed from the surrounding fascia and transected more proximally, thus removing a 3-cm section of muscle and do in the contralateral
During the minimally invasive myectomy damage to the cricothyroid muscles may result in what?
vocal cord collapse
What are the postoperative NSAID administration guidelines for minimally invasive myectomy?
For 3 to 7 days.
Figure 45-25. Schematic drawing showing the principle of the laryngeal tie-forward procedure. (A) Lateral view: note that the sutures are placed from the basihyoid into the lateral and caudal aspects of the lamina of the thyroid cartilage. The suture is passed four times through the thyroid cartilage and the most dorsal bite is immediately ventral to the tendon of the sternothyroid muscle. (B) Ventral view: the sutures course on the dorsal surface of the basihyoid bone and are tied with a slip knot on the ventral aspect of the junction of basihyoid bone and lingual process.
What anatomical structure does the laryngeal tie-forward aim to reposition?
The thyroid cartilage relative to the basihyoid bone.
How far rostral should the thyroid cartilage be positioned post-tie-forward surgery?
0.1 to 1.5 cm rostral to the caudal border of the basihyoid bone.
How long should the horse be kept in a stall postoperatively after a laryngeal tie-forward?
2 weeks.
What percentage increase in success rate is expected from laryngeal tie-forward compared to standard myectomy?
20% greater.
What is the length of the standard incision for a standard myectomy?
10 cm.
What is the significance of marking the resection site before laser-assisted staphylectomy
To prevent excessive resection due to the palate’s elasticity
What suture pattern is used to close the laryngotomy site?
Simple-continuous pattern.
What anatomical muscle is commonly resected during a standard myectomy?
Sternohyoideus.
What is the expected recovery time before resuming training after a minimally invasive myectomy for Standardbreds?
2 to 3 days.
How is the sternohyoideus muscle managed during a laryngeal tie-forward?
It is separated and dissected free.
What type of retractor is often used during laryngotomy?
Weitlaner or Hobday retractor.
What is the consequence of excessive soft palate resection in horses?
Dysphagia and potential aspiration pneumonia.
What are the anatomical landmarks for making a laryngotomy incision?
Centered over the cricothyroid space.
What are common postoperative assessments for laryngeal tie-forward surgery?
Endoscopic evaluation and radiographs with head in an extended position.
What is the principle of tie forward?
The principle of the procedure is to replace the action of the thyrohoideus muscles bilaterally by sutures placed between the thyroid cartilage and the basihyoid bone (fig 45-25)
Describe surgical approach of TIE FORWARD
The ventral cervical and intermandibular areas extending 10 cm rostral to the basihyoid bone are prepared aseptically. A ventral skin incision is made starting 1 cm caudal to the cricoid cartilage and extending 2 cm rostral to the caudal aspect of the basihyoid bone. The sternohyoideus muscle is separated on the midline and bluntly dissected free of the dorsolateral aspect of the larynx lateral to the thyrohyoideus muscles. The sutures are first passed through the thyroid cartilage. A No. 5 USP polyblend suture (Fiberwire) is passed four times through the right lamina of the thyroid cartilage ventral to the insertion of the sternothyroid tendon (see Figure 45-25, and Figure 45-26). Alternatively, a metal buttress is placed on the medial side of the thyroid cartilage to minimize cutting of the thyroid cartilage with sutures (F. Rossignol, personal communication, 2010). The junction of the basihyoid and lingual process is identified with a Crile forceps after limited blunt dissection, and a wire passer is inserted dorsal to the basihyoid bone immediately lateral to the lingual process. The wire passer courses over the dorsal aspect of the basihyoid bone and exits on the midline at the caudal aspect of the basihyoid bone (Figure 45-27). After the needle has been cut from the sutures, the dorsal (leader) and the ventral (trailer) ends of suture of the contralateral side are passed into the wire passer and retrieved. The procedure is repeated on the other side (Figure 45-28) such that the dorsal (leader) and ventral (trailer) ends of the sutures of each side can be tied over the ventral aspect of the basihyoid. A bilateral partial sternothyroidectomy is performed at this time
The sutures on each side are then tied so the rostral aspect of the thyroid cartilage is located immediately dorsal and ____ to ___ cm rostral to the caudal border of the basihyoid bone
The sutures on each side are then tied so the rostral aspect of the thyroid cartilage is located immediately dorsal and 0.1 to 1.5 cm rostral to the caudal border of the basihyoid bone
In the postop management of tie forward it is important that the horses is placed in which position?
ostoperatively the horses are fed and watered at shoulder height to reduce stress on the sutures. They are administered NSAI Ds for 3 to 5 days. Horses are maintained in a box stall for 2 weeks with daily hand walking. Training often is resumed 2 to 3 days after this rest period.
Figure 45-26. Intraoperative view of the laryngeal tie-forward procedure. Surgical view showing one suture passed twice (approximately 1-cm bites) through the lamina of the thyroid cartilage with the most dorsal suture entering ventral to the tendon of the sternothyroid tendon. This gives a dorsal (leader) and ventral (trailer) end of the sutures that will be passed around the basihyoid bone. Orientation: caudal (left), rostral
(right).
Figure 45-27. Intraoperative view of the laryngeal tie-forward procedure. Surgical view showing a wire passer in place where it enters immediately lateral to the lingual process in the corner (white arrows) of the junction of the basihyoid and lingual process. The wire passer courses over the dorsal aspect of the basihyoid bone and exits on the midline at the caudal aspect of the basihyoid bone (black arrow). Orientation: caudal (bottom), rostral (top).
Figure 45-28. Intraoperative view of the laryngeal tie-forward procedure, after the sutures have been placed so that the dorsal suture (leader) has been passed ipsilateral to the lingual process and the ventral (trailer) end is passed on the contralateral side. Orientation: caudal (left), rostral (right).
Figure 45-29. Postoperative view of the larynx in a 3-year-old Standardbred filly. Note that the epiglottis is elevated and not contacting the soft palate.
Figure 45-30. Lateral radiograph of a 3-year-old Thoroughbred filly with intermittent displacement of the soft palate prior to surgery (A) and after laryngeal tie-forward (B). Note the tip of the epiglottis is more rostral and dorsal after surgery. Also, the ossification at the base of the thyroid cartilage (white arrow) is more rostral and dorsal after surgery. Linear white densities are 5-cm pins used to measure magnification of radiographs.
Figure 45-31. Cleft palate repair via mandibular symphysiotomy. (A, B’ and B) A ventral midline incision is made from the angle of the mandible to the lip. Before splitting the symphysis, a hole is prepared to facilitate realignment of the bones during closure. The lip has been moved orally to avoid morbidity associated with incising it. (B) a, Mylohyoideus; b, mandibular lymph nodes; c, sternohyoideus and omohyoideus muscles
(C) The mandibles are spread, and the rostral oral mucosa is incised. The mylohyoid and geniohyoideus muscles are incised near their tendinous origin. They should be cut with enough tissue left to suture them together for closure. (D) The exposed ventral surface of the oral mucosa is tensed by further spreading of the mandibles. It is incised as far caudad as possible. Care is taken to avoid the sublingual salivary gland near the mandible and the lingual nerve near the tongue. (E) The edges of the incision are covered with moistened sponges or towels and spread as far as possible. The nasotracheal tube is visible through the cleft. Two stay sutures are placed at the caudal corners of the cleft.
(F) Tensing the edges of the cleft with the stay suture, a No. 12 Bard-Parker blade is used to split the thickness of the tissue. The stay sutures can be held by an instrument inserted through a laryngotomy. (G) A simple-continuous (or a Lembert) pattern is placed in the nasal side of the split edge in a rostral-to-caudal direction. (H) A continuous horizontal mattress pattern is placed in the oral side of the split edge. Two to four widely spaced interrupted vertical mattress sutures are placed to reduce tension on the primary suture line. (I) Soft tissues are apposed and a lag screw or pin with figure-of-eight wire is placed using the previously drilled hole. A cerclage wire around the rostral mandible just caudal to the erupted incisors augments stability.
Figure
Figure 45-32. Laryngotomy approach for repair of the caudal aspect of a cleft palate. The two parts of the cleft palate are retracted with Allis forceps. Good visibility of the cleft palate was achieved by splitting the thyroid cartilage longitudinally.
