Sphenoethmoid cerebrospinal fluid leak repair with hydroxyapatite cement.

Despite advances in neurological, reconstructive, and endoscopic sinus surgery, sphenoethmoid cerebrospinal fluid (CSF) fistulae continually pose difficult management problems. Standard surgical techniques for fistulae closure succeed approximately 78% to 90% of the time. To improve this success rate, hydroxyapatite cement (HAC), a Food and Drug Administration-approved substance for cranial defect repair, was applied to this problem in a clinical setting. Twenty-one patients with spontaneous, posttraumatic, or postoperative CSF leaks of the sphenoid sinus, cribriform plate, or ethmoid region were treated with HAC. Study participants were prospectively accrued at 5 tertiary care medical centers in the eastern United States. The CSF leaks of all 21 patients treated with HAC were successfully sealed by its initial application. The sites of CSF leakage included the nasal cavity (n = 2) and sphenoid sinus (n = 19). Fifteen of the patients had previously undergone a failed repair by standard methods. There have been no recurrent CSF leaks with a maximum follow-up of 72 months, and an average follow-up of 36 months. All patients have survived to date. The only HAC-related morbidity was the extrusion of the HAC when placed in the nasal cavity. Hydroxyapatite cement is an effective method of repair for postoperative, posttraumatic, and spontaneous sphenoid CSF leaks. The efficacy of HAC in sealing the CSF leak was unaffected by previous attempts at leak closure by standard methods or by its origin. Hydroxyapatite cement should not be applied transnasally for the treatment of an ethmoid region fistula owing to its high probability of extrusion. Correct patient selection and technical familiarity with HAC are necessary for successful application.

Human dural replacement with acellular dermis: clinical results and a review of the literature.

BACKGROUND: The search for the ideal dural replacement in the setting where autogenous tissues are unavailable or inadequate still persists. Because of the ability of acellular dermis (AlloDerm, LifeCell Corporation, The Woodlands, TX) to remodel itself into native tissue, this dynamic quality is hypothesized to occur when used as a dural replacement. METHODS: We report the long-term outcome of a small cohort of patients who, to our knowledge, were the first patients to receive AlloDerm for dural replacement. In addition, to put these current findings in a historical perspective, we present a review of the literature for dural replacement. RESULTS: Ten patients all successfully underwent duraplasty with AlloDerm with only one postoperative complication that was not related to the acellular dermal dural repair. CONCLUSIONS: We contend that AlloDerm is a safe and viable option for dural replacement in cases in which autogenous tissues are either unavailable or insufficient for proper reconstruction.

Identification of intranasal cerebrospinal fluid leaks by topical application with fluorescein dye.

The purpose of this paper is to describe a safe new technique for intraoperative identification of the site of cerebrospinal fluid rhinorrhea. Cerebrospinal fluid (CSF) rhinorrhea after intracranial or intranasal surgery is a known potential complication with significant morbidity and mortality. It is currently accepted that endoscopic intranasal management of CSF rhinorrhea is the preferred method of surgical repair, with higher success rates and less morbidity than intracranial surgical repair in selected cases. Accurate identification of the site of CSF leakage is necessary for a successful endoscopic surgical repair. Computer tomography (CT) with or without intrathecal contrast and preoperative nasal endoscopy are frequently used to preoperatively localize the site of the leak. Intrathecal fluorescein administered immediately before surgery has aided in the intraoperative identification of the site of CSF leak in 25-64% of patients undergoing endoscopic repair of CSF rhinorrhea in whom preoperative CT scanning and nasal endoscopy had not identified the site of CSF leak. Intrathecal fluorescein, however, has been associated with severe complications, such as lower extremity weakness, numbness, generalized seizures, opisthotonus, and cranial nerve deficits. We present three cases of CSF rhinorrhea in which fluorescein was applied intranasally during the endoscopic surgical repair. Ten percent fluorescein was applied to the nose with a cotton swab. Under endoscopic visualization the fluorescein changed its fluorescent color from amber/yellow to a dark green and was found streaming from high in the nasal cavity, which led to accurate identification of the site of the CSF leak.

A potential role for nasal obstruction in development of acute sinusitis: an infection study in rabbits.

The sequence of events that predispose to the onset of sinusitis are usually attributed to pathophysiologic factors within the ostiomeatal complex. Ostial compromise or obstruction with reduced clearance of antral pathogens has been implicated as a major factor that contributes to early sinus disease. Recent work in this laboratory has indicated that other processes may also contribute to this cascade. Using an infectious model in rabbits, the role of nasal obstruction in early, acute sinusitis was studied. Unilateral nasal closure was followed by bilateral inoculation with 10(8) CFU of Streptococcus pneumoniae type 3. Antral gas composition was examined on days 1, 2, 3, 5, 7, and 14, and swabs obtained for culture. Representative rabbits underwent CT scans to evaluate changes in nasal and sinus mucosa. Results showed a significant increase in CO2 and a trend toward a decrease in O2 on the obstructed side. There was also a significant decrease in obstructed CO2 levels from postoperative days (POD) 1-14. Acute sinusitis was not observed in any animal: however, nasal obstruction gave rise to a dramatic prolongation of bacterial retention. On days 2-7 bacteria was consistently cultured from the obstructed side only. CT scans on POD 2 and POD 3 showed mucosal thickening in the sinus and infundibulum on the obstructed side, indicative of sinus pathology. These results indicate that nasal obstruction may be a key factor in the cascade of events that predispose to the onset of sinus disease.

Maxillary sinus mucosal blood flow during nasal vs tracheal respiration.

OBJECTIVE: To determine the effect of changes from nasal to tracheal respiration on maxillary sinus mucosal blood flow in rabbits with unobstructed sinus ostia. DESIGN: Animals underwent tracheotomy with a T tube and then a small window of intact maxillary sinus mucosa was exposed. Mucosal blood flow was recorded during normal nasal respiration using laser-Doppler velocimetry. At hourly intervals, respiration was changed from the nasal to the tracheal route and then back again. SUBJECTS: Ten anesthetized rabbits were used: 5 underwent single and 4 underwent multiple shifts in the respiratory route, while 1 was monitored continuously during long-term nasal breathing only. RESULTS: A significant decrease in maxillary sinus blood flow occurred on switching from nasal to tracheal respiration and a significant increase in blood flow occurred on return to nasal respiration. Where multiple switches were made, blood flow changes diminished in magnitude, but significant decreases (nasal to tracheal) or increases (tracheal to nasal) were evident in all cases. CONCLUSIONS: It is proposed that the maxillary sinus may act in an accessory capacity to the nose for humidification of inspired air via secretions liberated from the sinus ostium. Furthermore, we suggest that nasal airflow is involved with the reflex regulation of sinus blood flow, probably via stimulation of sensory receptors in the nasal cavity. Reduced maxillary sinus mucosal blood flow may thus contribute to supra-systemic levels of antral carbon dioxide. Since elevated carbon dioxide levels have been shown to reduce maxillary sinus mucociliary activity in vitro, nasal airflow compromise may contribute to the initiation of a cascade of pathophysiological events leading to acute sinusitis.