Hypopharyngeal hemangiomas are uncommon neoplasms that can cause dysphagia, recurrent bleeding, and airway obstruction. These lesions are a therapeutic challenge, and surgical resection is the mainstay of therapy. The goal of therapy is directed at control of the tumor and relief of symptoms rather than total eradication of the lesion.
Laser therapy is a very useful adjunct in the management of these vascular neoplasms. The neodymium: yttrium-aluminum-garnet laser (Nd:YAG laser) functions at a wavelength that provides deep thermal coagulation. This allows its use for these vascular lesions. With laser surgery, hemorrhage is the most frequent and dangerous complication, and its control is extremely important. Ligation and suture remain the traditional methods of hemostasis in most surgical situations. However, on certain occasions problems arise, particularly with large oozing surfaces or when surgical access is poor. Topical hemostatic agents are widely used in a variety of surgical procedures to successfully solve such problems. Microfibrillar collagen (Avitene) is one of the absorbable, topical, hemostatic agents, and is used effectively to control bleeding in many surgical situations. Since we began to use microfibrillar collagen (AviteneTM, MedchemProduct, Inc., Woburn, MA01801) to stop the massive oozing of the laser-induced surgical wound, no episodes of bleeding had ever occurred. It is concluded that Avitene is an effective agent for maintaining hemostasis in many surgical procedures, and we consider it a good remedy for management of laser-induced bleeding complications. (Chang Gung Med J 2003;26:65-9)
Keywords：
microfibrillar collagen (Avitene), hypopharyngeal hemangioma, Nd:YAG laser.

CASE REPORT

A 32-year-old man presented with a six-month history of a globus sensation. He denied otalgia, chronic cough, dysphagia, or change of voice. Physical examination revealed normal findings in ear, nose, nasopharynx, and oropharynx. Examination by flexible endoscopy demonstrated a purple tumor mass with a smooth contour at the right pyriform sinus. The vocal cord is free in motion. Computed tomography (CT) identified extension of the lesion into the right para-laryngeal space and slight enhancement of the lesion after intravenous contrast medium injection (Fig. 1). As angiography showed no definite tumor vessels, tumor stain, or abnormal arteriovenous (AV) shunting at the laryngeal area, embolization was not performed.
The patient underwent suspension microlaryngoscopy under general anesthesia, revealing a hemangioma of the right hypopharynx (Fig. 2). We performed Nd:YAG photocoagulation with the laser set at 15 W in the continuous mode. A profuse oozing was encountered during photoablation, and attempts to achieve hemostasis with compression, pressure, electrocautery, and suture ligatures were unsuccessful. Thus, we introduced Avitene upon the bleeding site using sterile forceps; then, pressure was applied until the bleeding stopped. The blood loss was estimated to be about 100 c.c..
Microscopically, the tumor tissue was composed of aggregates of irregular dilated blood channels and capillaries lined by flattened endothelium, and the vessels' luminae were filled with blood cells. The histopathological diagnosis was hypopharyngeal hemangioma (Fig 3). Thereafter, there was no episode of bleeding. The patient made a good recovery without voice change or airway distress, and was discharged on the third postoperative day. He has done well, with complete resolution of his symptoms,although a 3-month follow-up examination in the office revealed the remaining residual hemangioma on the right hypopharynx (Fig. 4). Furthermore, no postoperative cicatrix was noted, and the patient had a satisfactory postoperative course.

DISCUSSION

Hypopharyngeal hemangiomas are uncommon neoplasms(1) that can cause dysphagia, recurrent bleeding, and airway obstruction. These lesions are a therapeutic challenge, and surgical resection is the mainstay of therapy. Hypopharyngeal hemangiomas are usually of the cavernous or mixed type, with a thin, friable mucosa overlying the vascular stroma.(2) Preoperative CT with contrast enhancement and angiography are helpful in both planning the surgical procedure and avoiding injury to adjacent vessels. Laser therapy is a very useful adjunct in the management of these vascular neoplasms.
Photocoagulation with the Nd:YAG laser offers the clinician an effective alternative therapy to open surgical procedures. The Nd:YAG laser, at 1.06 mm, has the longest penetration depth of any of the surgical lasers. The tissue characteristics of the Nd:YAG laser result in deep penetration and scatter of laser energy that is preferentially absorbed by pigmented or vascular tissue. This laser produces a homogenous zone of thermal coagulation and necrosis that may extend 4 mm from the impact site, thereby providing deep thermal coagulation.(3) These characteristics allow its use for vascular lesions. If too much laser energy is directed in one spot, the result may be mucosal disruption and hemorrhage. Excessive bleeding also results from extravasation of the contents of the hemangioma into adjacent normal tissue, or rupture of the capsule. Hemorrhage is the most frequent and dangerous complication associated with laser surgery, and its control is extremely important. In our case, the patient did not undergo superselective embolization because there were no definite tumor vessels, tumor stain, or abnormal AV shunting in the laryngeal area on angiography.
As hemangiomas are benign lesions, it is better to undertreat them and monitor their evolution over time than to damage healthy tissue. The goal of therapy is directed at control of the tumor and relief of symptoms rather than total eradication of the lesion.(4)
Ligation and suture remain the traditional methods of hemostasis in most surgical situations. However, on certain occasions problems arise, particularly with large oozing surfaces or when surgical access is poor. Topical hemostatic agents are widely used in a variety of surgical procedures. Microfi-brillar collagen (Avitene) is an absorbable, topical, hemostatic agent that is used effectively to control bleeding in many surgical situations. It is insoluble in water and consists of a dry, fluffy, off-white powder. It provides a surface for platelet adhesion. The platelets adhere to the collagen surface and then undergo a release reaction that leads to aggregation of surrounding platelets and clot formation. Avitene is inactivated by autoclaving and, therefore, cannot be reused. Avitene is used by applying the powder with dry instruments to the bleeding site, which has previously been cleaned of excess blood.(5) Pressure is placed to the area of application. When hemostasis occurs, the excess Avitene that has not been incorporated into the clot is removed gradually. Recurrence of bleeding following removal of excess collagen can be controlled by reapplication. Topical hemostatic agents are potentiators of infection and should be used in the smallest quantities possible where a risk of bacterial contamination exists.(6) Uses of Avitene in otorhinolaryngologic surgery have been described in nonsurgical repair of extratemporal facial nerves,(7) tracheal autograft prefabrication,(8) and hemostasis in epistaxis.(9)
It is important to note that topical hemostatic agents are not used to stop arterial bleeding. Rather, they are used to control oozing from raw surfaces. Avitene offers effective hemostasis of diffuse oozing surfaces, such as occurs with laser surgery. Precautions against aspiration should include removal of all excess dry material. To the best of the authors' knowledge, there is no previous report of bleeding management with microfibrillar collagen for control of oozing blood loss as a complication of laser laryngomicrosurgery.
In conclusion, microfibrillar collagen can be used as an adjunct in hemostasis when control of bleeding by ligature or conventional procedures is ineffective or impractical. From our experience, we found that it is a good remedy for management of bleeding as a complication of laser surgery.

REFERENCES

1. Guo YC, Chu PY, Ho DM, Chang SY. Hemangioma of the pyriform sinus. Otolaryngol Head Neck Surg 2001; 124:707-8.
2. Sie KC, Tampakopoulou DA. Hemangioma and vascular malformations of the airway. Otolaryngol Clin North Am 2000;33:209-20.
3. Courey MS, Ossoff RH. Laser applications in adult laryngeal surgery. Otolaryngol Clin North Am 1996;29:973-84.
4. Yellin SA, Labruna A, Anand VK. Nd:YAG laser treatment for laryngeal and hypopharyngeal hemangioma: a new technique. Ann Otol Rhinol Laryngol 1996; 105:510-15.
5. Decker CJ. An efficient method for the application of Avetene hemostatic agent. Surg Gynecol & Obstet 1991; 172:489.
6. Kenneth SS, James A CJ. Effects of oxidized cellulose and microfibrillar collagen on infection. Surgery 1982; 91:301-4.
7. Parker G. Surgical repair of extratemporal facial nerve: a comparison of suture repair and microfibrillar collagen repair. Laryngoscope 1984;94:950-3.
8. Daniel BK, Jose NF. Tracheal autograft prefabrication using microfibrillar collagen and bone morphogenetic protein. Arch Otolaryngol Head Neck Surg 1996;122: 1385-9.
9. Walike JW, Chinn J. Evaluation and treatment of acute bleeding from the head and neck. Ear Nose Throat Clin North Am 1979;12:455-63.

From the Department of Otolaryngology, Chang Gung Memorial Hospital, Taipei, Chang Gung University, Taoyuan, Taiwan.
Received: Jan. 2, 2002; Accepted: Apr. 26, 2002
Address for reprints: Dr. Hsueh-Yu Li, Department of Otolaryngology, Chang Gung Memorial Hospital. 5, Fu Shin Street, Kweishan, Taoyuan 333, Taiwan, R. O. C. Tel.: 886-3-3281200 ext. 3967; Fax: 886-3-3279361; E-mail: hyli38@cgmh.org.tw