Satish Govindaraj

Applications of Fast-Setting Hydroxyapatite Cement: Cranioplasty

A variety of autogenous and synthetic materials have been used to repair cranial defects resulting from traumatic and iatrogenic causes. In theory, the ideal material should be readily available and safe. It should adequately protect the underlying central nervous system, resist cerebrospinal fluid fistula formation, and be easily contoured. One promising synthetic biomaterial that has been used for cranioplasty is hydroxyapatite cement. This biomaterial has successfully restored cranial contour in most patients in whom it has been used; however, difficulties have arisen because of the materials prolonged water solubility. When exposed to cerebrospinal fluid or blood, inadequate setting of the cement occurs, resulting in loss of its structural integrity. This problem can be alleviated with the use of fast-setting hydroxyapatite cement, which hardens 6 to 12 times faster than the traditional cement. We present, to the best of our knowledge, the first series of the use of this material in 21 patients requiring cranioplasty. The advantages and limitations of fast-setting hydroxyapatite cement will be discussed. (Otolaryngol Head Neck Surg 2000; 123:409-12.)

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

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.

The use of acellular dermis in the prevention of Frey's syndrome.

Educational Objective At the conclusion of this presentation, the participant should be able to discuss the indications and advantages of using acellular dermis in the prevention of post‐parotidectomy gustatory sweating (Freys Syndrome).

A meta-analysis of dexamethasone use with tonsillectomy

ABSTRACT OBJECTIVE: To determine the quantitative impact of intravenous dexamethasone on recovery after ton-sillectomy using established principles for meta-analysis. STUDY DESIGN/SETTING: Double-blind randomized-control trials in which subjects were treated identically except for the presence or absence of peri-operative intravenous dexamethasone. Six articles met inclusion criteria. Two investigators extracted data regarding postoperative emesis and return to a soft/regular diet. RESULTS: Pooled analysis using a random effects model revealed a 27% decrease (P < 0.00001) in postoperative emesis attributable to dexamethasone (95% CI, 12% to 42%). Dexamethasone increased the tolerance of a soft/regular diet at 24 hours by 22% (P < 0.001), but studies were heterogenous with low precision (95% CI, 1% to 44%). CONCLUSION: To prevent emesis in 1 child after tonsillectomy, approximately 4 children must receive perioperative dexamethasone. An additional benefit is earlier tolerance of a soft/regular diet, but low precision and heterogeneity among studies preclude definitive conclusions. SIGNIFICANCE: Perioperative dexamethasone administration had a positive impact on recovery from tonsillectomy.

Tympanic Membrane Repair With a Dermal Allograft

Objectives To assess the use of an acellular dermal allograft in the repair of chronic tympanic membrane perforations. Chronic tympanic membrane perforations are a common problem in otolaryngology, and although surgical tympanoplasty using either temporalis fascia or rice paper has proven to be highly successful, these materials are not without their own limitations. The search has continued for a simpler, yet equally effective, means of repairing persistent tympanic membrane perforations in an office setting. In this study we experimentally evaluated the use of an acellular dermis (AlloDerm, (LifeCell Corporation, The Woodlands, TX) as an alternative to traditional tympanoplasty materials.

Endoscopic sinus surgery: evolution and technical innovations

Prior to the introduction of functional endoscopic sinus surgery, several surgeons had begun to use telescopes to perform surgical procedures in the nose and sinuses. However, the central concepts of functional endoscopic sinus surgery evolved primarily from Messerklingers endoscopic study of mucociliary clearance and endoscopic detailing of intranasal pathology. The popularity of a combination of endoscopic ethmoidectomy plus opening of secondarily involved sinuses grew rapidly during the latter part of the twentieth century, and endoscopic intranasal techniques began to expand to deal with pathology other than inflammation. We present a review of the evolution of knowledge regarding the pathogenesis of inflammatory sinus disease since that point in time, and of the impact that this has had on the management of inflammatory sinus disease. We also detail the technological advances that have allowed endoscopic intranasal techniques to expand and successfully treat other pathology, including skull base and orbital disease. In addition, we describe evolving technologies which may further influence development within this field.

Sinonasal melanoma: survival and prognostic implications based on site of involvement

Sinonasal melanoma (SNM) is a rare malignancy that commonly presents at an advanced age and has a slight male predominance. Local recurrence has been implicated as a major reason for treatment failure, and there are poor reported 5‐year survival rates. We analyzed the impact of specific location within the sinonasal region on the survival of this rare malignancy.

Diffuse large B-cell lymphoma of the sinonasal tract: Analysis of survival in 852 cases

PURPOSE Diffuse large B-cell lymphomas (DLBCLs) are rare tumors of the head and neck that often have non-specific presentations and significant morbidity and mortality. In this analysis we use a large cohort to compare the demographic and disease-specific parameters affecting survival and incidence of DLBCLs. METHODS The United States National Cancer Institutes Surveillance, Epidemiology, and End Results (SEER) registry was utilized to extract data regarding sinonasal diffuse large B-cell lymphoma between 1973 and 2009. A total of 852 cases of sinonasal DLBCLs were found. Presenting symptoms, demographics, disease specific survival, relative survival and survival by treatment modality were described for this rare tumor. RESULTS Overall disease specific survival (DSS) at 1-year was 84.7% and at 5 years was 68.0%. DSS was significantly lower for those not treated with radiation therapy, with 1- and 5-year survival rates of 77.3% and 62.5%, versus those treated with radiation therapy, with 1- and 5-year rates of 89.2% and 71.5% (p<0.05). Prognosis was significantly better for patients treated with radiation therapy (HR 0.6, p<0.05) while it was poorer for patients with involvement of multiple sinuses (HR 1.5, 1.8, p<0.05). CONCLUSIONS DLBCLs of the sinonasal tract are rare tumors of the head and neck. Survival is significantly improved for those treated with radiation therapy while the involvement of multiple sinuses is a negative prognostic indicator.

Salvage endoscopic nasoseptal flap repair of persistent cerebrospinal fluid leak after open skull base surgery

PURPOSE Persistent cerebrospinal fluid (CSF) rhinorrhea after open skull base surgery can be challenging to manage due to the risk of meningitis, brain abscess, surgical morbidity associated with revision craniotomy, and the lack of available healthy autologous tissue after failure of a pericranial flap. Given the recent success of the vascularized pedicled nasoseptal flap (PNSF) for reconstruction after endoscopic skull base surgery, we have adopted this technique as a salvage method to treat recalcitrant CSF rhinorrhea after previous open skull base surgery in order to avoid revision craniotomy. To our knowledge, use of the PNSF in this setting has not been previously described in the literature. METHODS A retrospective analysis was performed on 4 patients who underwent endoscopic endonasal PNSF repair of persistent CSF rhinorrhea after having undergone previous open transcranial skull base operation. Pathologies consisted of one sinonasal anterior skull base squamous cell carcinoma, one recurrent petrosal skull base meningioma, and 2 traumatic gunshot wounds to the head. RESULTS All 4 patients underwent successful repair of CSF rhinorrhea without complications using the salvage endoscopic endonasal PNSF technique after a mean follow-up of 21.5 months. CONCLUSIONS In patients who have undergone previous open skull base surgery as the primary approach, persistent CSF rhinorrhea can be safely repaired using the vascularized PNSF via an endoscopic endonasal approach. This minimally invasive strategy has the advantage of providing new healthy vascularized tissue for skull base reconstruction while avoiding revision craniotomy.

Reepithelialization of orthotopic tracheal allografts prevents rejection after withdrawal of immunosuppression.

Prior work has demonstrated that immunosuppressed orthotopic tracheal allografts undergo progressive reepithelialization over a 48-day period with recipient-derived tracheal epithelium. We hypothesized that reepithelialization of tracheal allografts would prevent rejection after withdrawal of immunosuppression. BALB/c murine tracheal grafts were transplanted orthotopically into either syngeneic or allogeneic C57/BL6 recipients. The recipients were either not immunosuppressed, immunosuppressed with cyclosporine A (10 mg/kg per day) continuously, or immunosuppressed for 48 days and then withdrawn from immunosuppression. The grafts were assessed for acute and chronic rejection 10 days and 50 days after immunosuppression withdrawal. The immunosuppressed allograft recipients maintained a ciliated epithelium acutely and chronically after immunosuppression withdrawal. Ten days after immunosuppression withdrawal, there was a mild cellular infiltrate, which resolved 50 days after withdrawal. Electron microscopy, lymphocyte subpopulation assays, and lamina propria analysis demonstrated that immunosuppression withdrawal did not result in tracheal allograft rejection. In vitro and in vivo assessments did not demonstrate evidence of systemic or local immune tolerance. We conclude that reepithelialization of orthotopic tracheal allografts with recipient-derived mucosa prevents rejection of allograft segments. Tracheal transplantation may require only transient immunosuppression, which can be withdrawn after tracheal reepithelialization.