Department of Otorhinolaryngology - Head and Neck Surgery

McGovern Medical School

Research Update

Otorhinolaryngologists at The University of Texas Health Science Center at Houston (UTHealth) Medical School and Memorial Hermann-Texas Medical Center are engaged in research efforts that drive the innovation that moves medicine forward into the future.  The following reports were presented at the 2011 annual meetings of the American Academy of Otolaryngology-Head and Neck Surgery, the American Academy of Otolaryngic Allergy, the American Academy of Facial Plastic Surgery and the American Rhinologic Society in San Francisco, CA.

Increased Percentage of Mast Cells Within Sinonasal Mucosa of Chronic Rhinosinusitis with Nasal Polyp Independent of Atopy

While surgery in appropriate patients may be a good initial step in the treatment of chronic rhinosinusitis (CRS), patients are at risk of relapse as long as the disease is not well understood.   Through her research, Amber Luong, MD, PhD, is seeking to discover the best course for continued CRS treatment once surgery allows access to the diseased sinus mucosa.

“Because there is currently no curative treatment for chronic rhinosinusitis, all medications are prescribed to control symptoms,” says Dr.  Luong, an assistant professor and director of research in the department of Otorhinolaryngology-Head and Neck Surgery at McGovern Medical School.   “Most research aimed at understanding the pathophysiology of CRS has been focused on eosinophils, white blood cells that are one component of the immune system responsible for fighting infections.  We’re looking for new pathways that may lead to better treatment.”

To that end, she and her research team are examining the role of mast cells in CRS.  “Chronic rhinosinusitis is typically classified by the presence or absence of nasal polyps,” she says.  “We’ve found that CRS sufferers with nasal polyps have elevated levels of mast cells, which suggests that mast cells are playing an important role, either in the formation or maintenance of the disease.”

The researchers examined ethmoid sinonasal mucosa from three groups of patients who underwent endoscopic sinus surgery: healthy controls, patients with CRS without nasal polyps and patients with CRS with nasal polyps.  The results were presented at the American Rhinologic Society annual meeting held last September in San Francisco.

“To understand the role of mast cells, we looked at an enzyme called prostaglandin D2 synthase, which is made primarily by mast cells.  We found elevated levels of the enzyme in CRS patients with nasal polyps, regardless of whether they had a genetic predisposition toward atopic allergy, which is most commonly manifested as allergic rhinitis,” Dr.  Luong says.

“Our results reveal a pathway that may be important in the treatment of CRS,” she says.  “There are medications that stabilize mast cells.  They might ultimately be effective in the treatment of CRS.”

Histopathological Analysis of Irradiated Costal Cartilage Homograft vs.  Costal Cartilage Autograft in the Rabbit Model

Structural cartilage grafting plays an important role in functional and aesthetic nasal reconstructive surgery.  While conventional wisdom holds that irradiated costal cartilage homographs taken from cadavers tend to be resorbed by the body faster than autogenous grafts using the patient’s own bone, a study done at UTHealth and Memorial Hermann has shed new light on the issue.

“The goal of our study was to learn more about how the two types of costal cartilage grafts interact in vivo in the body and to determine which type of graft survives longer,” says principal investigator Tang Ho, MD, MSc, assistant professor of facial plastic and reconstructive surgery in the Department of Otorhinolaryngology at the UTHealth Medical School.

Nine New Zealand White rabbits, including one homograft donor animal and eight experimental animals, were used for the study.  Thirty costal cartilage homografts were harvested from the donor animal and irradiated using a Cesium-137 source.  The remaining eight study rabbits underwent surgical costal cartilage graft harvest and implantation.  Three irradiated homographs and three fresh costal cartilage autografts were implanted along the midline nasal dorsum of each experimental animal.  The results of the study were presented by resident Ibrahim Alava, MD, a fourth-year resident in the department, at the annual meeting of the American Academy of Facial Plastic and Reconstructive Surgery held last September in San Francisco.

“We found the density of the irradiated homografts and the autografts to be similar at the end of a three-month period,” Dr.  Ho says.  “The irradiated homografts produced very little inflammation in the surrounding tissue, and demonstrated replacement of the graft with calcifications, while the autografts caused more inflammatory response.  Both types of grafts held up fairly well, but the autogenous graft did maintain its bulk better.”

Pilot Study Comparing Total Intravenous to Inhalational Anesthesia in Endoscopic Sinus Surgery: A Novel Approach to Blood Flow Quantification

Providing a relatively bloodless surgical field during endoscopic sinus surgery under anesthesia is a critical factor for optimal visualization by the surgeon.  To learn how blood flow into the nose is affected by the type of anesthesia used, researchers at the UTHealth Medical School and Memorial Hermann conducted a study comparing total intravenous anesthesia (TIVA) to inhalational anesthesia.  They presented their results at the 2011 annual meeting of the American Academy of Otolaryngology last September.

“We found that the group that received TIVA had a higher blood flow to the nose starting midway through surgery to the end of the procedure, compared to the inhalational group,” says principal investigator Samer Fakhri, MD, FACS, FRCS(C), an associate professor and residency program director in the UTHealth Department of Otorhinolaryngology-Head and Neck Surgery.  “This is the first study to quantify that there is increased blood flow using TIVA over inhalational agents, and we objectively documented our results using optical rhinometry, a novel way of measuring blood flow into the nose.” Optical rhinometry uses a wavelength light emitter and an optical sensor placed across the bridge of the nose to detect changes in blood flow into the nasal mucosa.

Twenty-three patients with chronic rhinosinusitis with or without polyps, who were scheduled to undergo endoscopic sinus surgery, participated in the study.  Investigators used the Rhinolux system to measure nasal blood flow beginning with the induction of general anesthesia and continuing until the end of the procedure.  They measured blood loss by evaluating the volume in collection canisters and subtracting the volume of irrigation used during surgery.

There was no difference in surgical field quality between the two types of anesthesia, which was confirmed by four independent reviewers who assessed the operative field based on video recordings presented in a blinded fashion.  There was also no difference in total blood loss between the two groups.  In addition, the research team compared postoperative pain, nausea and vomiting, the need for pain medications and recovery time, and found no differences between the two groups.

“Our results go a little against some of the data published in the literature showing that TIVA is superior in terms of surgical field visualization and can lead to less blood loss,” Dr.  Fakhri says.  “We’ll be continuing our investigation in the future to determine the real significance of our results.”

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