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Biomedical subjects

J P Leonetti

Publications and source records attributed to J P Leonetti.

At least 19 recordsLinked to original sources
PubMed2001

Extracranial lower cranial nerve sheath tumors.

OBJECTIVE: The purpose of this article is to review the clinicoradiographic features of lower cranial nerve sheath tumors and to outline surgical approaches that allow the safe and complete resection of these lesions. METHODS: Thirteen patients with lower cranial nerve sheath tumors of the infratemporal fossa were surgically treated between 7/88 and 10/99. A retrospective chart analysis provided details pertaining to clinical manifestations, radiographic assessment, intraoperative findings, tumor histology, and postoperative results. RESULTS: The most common presenting symptoms were neck pressure and voice change while submucosal palatal fullness and vocal cord paralysis were the most common presenting signs. All tumors were removed via lateral skull base approaches and the most common postoperative sequelae was dysphasia. CONCLUSION: Lower cranial nerve sheath tumors of the infratemporal fossa usually reach considerable size before diagnosis because of a naturally slow growth rate in this relatively silent location. The safe surgical removal of these tumors, based on superior control of the internal carotid artery, can be achieved through the use of contemporary lateral skull base techniques.

Adult↗
PubMed2001

Duration of neuronal stretch correlates with functional loss.

Postoperative cranial nerve weakness or paralysis is not uncommon in many otolaryngologic surgical procedures. Our study used a rat model to test the hypothesis that the length of time that a nerve is under tension may be an important variable in the amount of postoperative paresis. Forty Sprague-Dawley rats were divided into 4 groups that underwent either a sham operation or a traction injury for 1, 2, or 5 minutes. The traction injury was performed with a vessel loop placed around the sciatic nerve with 50 g of tension. Traction injury for 1 or 2 minutes did not result in any statistical differences in the motor capabilities of the lower limb. However, those animals with a stretch injury for 5 minutes had a significant loss of function (P < 0.01) when compared with all other groups. Histologic examination of nerves harvested on postoperative day 7 showed no evidence of mechanical injury. This study demonstrates that even minimal tension, if maintained for a significant amount of time, may result in postoperative weakness.

Animals↗
PubMed2001

Incidental petrous apex findings on magnetic resonance imaging.

We performed a retrospective chart review to categorize a group of petrous apex findings that were noted incidentally on magnetic resonance imaging (MRI) in 88 patients. These patients were among those who had been seen at a tertiary care center between July 1988 and July 1998. These incidental findings, which were unrelated to the presenting clinical manifestations, included asymmetric fatty bone marrow (n = 41), inflammation (19), cholesterol granulomas (14), cholesteatomas (9), and neoplasms (5). Followup imaging and clinical surveillance of these patients has not demonstrated any significant change in the incidentally detected lesions. In all cases, the incidental MRI findings represented benign pathology.

Adolescent↗
PubMed2000

Neuroprotection due to irrigation during bipolar cautery.

OBJECTIVE: To test whether irrigation during bipolar cautery confers thermoprotection from neuronal injury. DESIGN: A rat animal model (15 rats for each treatment group) was used to test the thermoprotective effects of irrigation during bipolar cautery. In this model, the sciatic nerve was exposed, and a 1-second stimulus was applied using bipolar cautery forceps at 40 or 20 W placed directly on the nerve in the presence or absence of simultaneous irrigation. The effects of cautery were determined on the basis of clinical gait analysis by means of the Sciatic Functional Index, temperature response, and neuropathological findings. RESULTS: The degree of paresis was reduced with irrigation. Neuropathological examination of the sciatic nerve after cautery showed significant axonal loss (more small than large fibers) with concomitant demyelination, which was partially inhibited by irrigation (chi2; P = .04). The mechanism of thermoprotection by irrigation was not the result of a reduction in the temperature spike that followed cautery, but resulted from a reduced temperature response during the 15 seconds that followed 40- or 20-W stimulation with bipolar cautery. CONCLUSIONS: Simultaneous irrigation and bipolar cautery enhance temperature recovery to basal levels and protect the peripheral nerve from the effects of cautery.

Animals↗
PubMed2000

Remifentanil-based anesthesia versus a propofol technique for otologic surgical procedures.

Otologic procedures require a still surgical field and are associated with a 50% incidence of emetic symptoms. Propofol reduces nausea and vomiting but not intraoperative movement. This study compares a remifentanil/propofol anesthetic to a propofol/fentanyl combination to determine which provides the best perioperative conditions for otologic microsurgery. Eighty healthy patients were randomly assigned to receive one of the anesthetic combinations. Demographic data, hemodynamic variables, movement, and bispectral index monitoring values in addition to anesthetic emergence, nausea, vomiting, pain, and other recovery variables were compared between groups with appropriate statistical methods. Both groups were similar. Times to eye opening (7.7 +/- 0.7 vs 12.4 +/- 1.2 minutes) and extubation (9.8 +/- 0.9 vs 12.4 +/- 1.0 minutes) were shorter with remifentanil. This group also had lower hemodynamic variables and movement (23% vs 65%) under anesthesia. Postoperative pain was mild in both groups, but remifentanil patients had more than the propofol group. All other postoperative parameters were similar. Remifentanil-based anesthesia produces better hemodynamic stability, less movement, and faster emergence after otologic surgery, with propofol's antiemetic effect, for the same cost.

Adolescent↗
PubMed2000

[Synthesis and properties of photolabile caged phosphotriester derivatives of dinucleoside phosphates].

Dinucleoside phosphates that harbor phosphate groups transiently blocked (caged) by o-nitrobenzyl or o-nitroveratryl residues were synthesized. It was shown that the conditions of the UV-induced deprotection largely depend on the nature of the protective group. The phosphotriesters obtained were resistant toward snake venom phosphodiesterase and nucleases of the cellular extract. The synthesis of the dinucleoside phosphates containing a photolabile group preceded the incorporation of the modified blocks into extended oligonucleotides by the phosphoramidite method.

Dinucleoside Phosphates↗
PubMed1999

Comparison of 3 different anesthetic techniques on 24-hour recovery after otologic surgical procedures.

Intravenous propofol anesthesia is better than inhalational anesthesia for otologic surgery, but cost and intraoperative movement make this technique prohibitive. This study compares a propofol sandwich anesthetic with a total propofol or inhalational anesthetic for otologic surgery to determine which produces the best perioperative conditions and least expense. One hundred twenty patients undergoing ear surgery were randomly chosen to receive an anesthetic with either isoflurane (INHAL), total propofol (TPROP), or propofol used in conjunction with isoflurane (PSAND). Postoperative wakeup and the incidence and severity of nausea, vomiting, and pain were compared among groups. Antiemetic administration and discharge times from recovery and the hospital were also compared. The groups were similar, but anesthesia times were longer in the INHAL group. Emergence from anesthesia after PSAND or TPROP was more rapid than after INHAL. Recovery during the next 24 hours was associated with less nausea and vomiting with PSAND than with INHAL. The cost of the PSAND anesthetic was similar to that of INHAL, and both were less than TPROP. PSAND anesthesia may be similar to TPROP and better than INHAL for otologic procedures. PSAND was less expensive than TPROP and produced a similar recovery profile and antiemetic effect in the 24-hour period after surgery.

Adult↗
PubMed1999

Treatment of malignant neoplasms of the lateral cranial base with the combined frontotemporal-anterolateral approach: five-year follow-up.

Technical advances in accessing the lateral cranial base have permitted disease in this area previously deemed inoperable to be resected. The procedures required to effect an oncologically adequate resection are often long and accompanied by the potential for serious, even life-threatening, complications. Although it has been demonstrated that such disease can be extirpated, the question of whether such heroic surgery improves long-term survival remains unanswered. We retrospectively reviewed the records of 25 patients who underwent a combination of frontotemporal craniotomy with other, more conventional, anterolateral procedures (eg, infratemporal fossa approach, maxillectomy, orbitectomy, mandibulopharyngectomy) to resect stage IV malignant disease of the lateral to midcranial base between 1983 and 1990. Perioperative deaths occurred in 2 patients, 1 patient died of unrelated causes free of disease, and 2 patients were lost to follow-up, leaving 20 patients with a minimum 5-year evaluation. Five (25%) of the 20 patients we monitored were free of disease. Of those patients in whom recurrent disease developed, local control was achieved in about 50%; however in 80% of those with recurrence, metastatic disease developed. Surgical treatment of selected stage IV malignant disease of the lateral to midcranial base appears to have provided long-term disease-free survival to 25% of patients in this series who would otherwise have had little hope of survival.

Adult↗
PubMed1998

Thermoprotective mechanisms of irrigation during bipolar cautery.

Bipolar cautery is routinely used in operations of the head and neck, as well as in other specialties, both for dissection and for achieving hemostasis. Whereas simultaneous irrigation is frequently used to minimize neuronal injury, its effectiveness has not been tested under controlled conditions. Our objectives in this study were to test the hypothesis that including irrigation during bipolar cautery is thermoprotective and to identify the mechanisms underlying the thermoprotective effect. The thermoprotective role of irrigation with bipolar cautery was tested in a rat model in which the sciatic nerve was exposed and a 1-second stimulus at 40 or 20 watts was applied with bipolar cautery forceps placed directly on the nerve in the presence or absence of simultaneous irrigation. We used the Sciatic Functional Index as used to quantitate the degree of paresis induced. The results showed that simultaneous irrigation reduced the percentage of animals showing paresis. This effect was significant for animals exposed to 40- and 20-watt cautery. The mechanism for the reduction in the degree of paresis by irrigation could not be attributed to a lowering of the maximal temperature achieved after bipolar cautery. Instead, the thermoprotective mechanism of the irrigation involved an enhanced recovery to basal temperatures when measured at 15 seconds after nerve stimulation with 40 or 20 watts. Reducing the power from 40 watts to 20 watts did not significantly lessen the tissue temperature. The results of this study suggest that irrigation done simultaneously with bipolar cautery enhances temperature recovery to basal levels and plays a role in thermoprotection against the effects of cautery.

Animals↗
PubMed1998

Ondansetron versus droperidol or placebo to prevent nausea and vomiting after otologic surgery.

This study compares the preoperative administration of ondansetron with that of droperidol or saline solution for the prevention of nausea and vomiting in otologic surgery patients. A total of 120 otherwise healthy individuals were randomly assigned to receive either saline solution, ondansetron (4 mg intravenously), or droperidol (25 microg/kg intravenously) before anesthetic induction. Intraoperative and postanesthesia care unit times were recorded along with incidence of nausea, vomiting, pain, nausea and recovery scores, and the administration of rescue antiemetics. Similar assessments were made during the next 24 hours. Demographics were similar, but more males received ondansetron. Anesthetic recovery scores were lower after administration of droperidol than after ondansetron. Incidence of nausea was similar between groups, but severity was greater with placebo and droperidol than with ondansetron. More vomiting occurred with placebo than with ondansetron or droperidol. No intergroup differences in rescue antiemetic administration were noted, however. Twenty-four hours later, more patients receiving placebo had nausea or vomited than patients receiving droperidol or ondansetron. Fewer women in the ondansetron group vomited than in the other two groups. Ondansetron 4 mg intravenously is as effective as droperidol and better than saline solution in preventing nausea and vomiting in patients undergoing otologic surgery. No cost advantage as determined by lower use of rescue antiemetics or shorter postanesthesia care unit times was noted after ondansetron therapy.

Adult↗
PubMed1998

Otalgia. An isolated symptom of malignant infratemporal tumors.

OBJECTIVE: This study aimed to review a series of 18 patients with malignant infratemporal fossa tumors who presented with otalgia as the primary symptom. STUDY DESIGN: This was a retrospective case analysis. SETTING: All patients were evaluated and treated at a tertiary care academic medical institution. PATIENTS: Eighteen patients evaluated for otalgia in a normal-appearing ear, between July 1988 and July 1996, who were found to have a malignant infratemporal fossa tumor participated. INTERVENTIONS: Diagnostic testing included radiographic evaluations and tissue sampling through fine-needle aspiration cytology. Treatment methods were histology dependent. MAIN OUTCOME MEASURES: The time between the onset of otalgia and the tumor diagnosis was recorded. Overall treatment outcomes were reviewed. RESULTS: The period between the onset of otalgia and tumor diagnosis ranged from 4-21 months with a mean of 7.5 months. Adenoid cystic carcinoma was the most commonly seen tumor in this series of patients. CONCLUSIONS: The infratemporal fossa is a relatively protected region that may be the site of malignant neoplasms causing the isolated symptom of otalgia.

Adult↗
PubMed1998

Cochlear neuromas.

OBJECTIVE: This study aimed to review the clinicoradiographic findings in 16 patients with unilateral cochlear neuromas. STUDY DESIGN: The data included in this presentation were obtained from a retrospective case review. SETTING: The study was conducted at a tertiary care academic institution. PATIENTS: Patients of any age, gender, or race with a unilateral cochlear neuroma participated. INTERVENTIONS: Standard audiometric and radiographic assessment was performed. MAIN OUTCOME MEASURES: Progressive sensorineural hearing loss was measured. RESULTS: Sensorineural hearing loss is out of proportion to the size of the tumor (< 8 mm in all 16 patients). CONCLUSIONS: Gadolinium-enhanced magnetic resonance imaging in the axial and coronal planes can help identify cochlear neuromas in selected patients with unilateral sensorineural hearing loss.

Adult↗
PubMed1997

Increased recurrence and metastasis in patients whose primary head and neck squamous cell carcinomas secreted granulocyte-macrophage colony-stimulating factor and contained CD34+ natural suppressor cells.

Human head and neck squamous cell carcinomas (HNSCC) that produce high levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) have been shown to contain CD34+ natural suppressor cells that inhibit the activity of intratumoral T-cells. The present study evaluated whether GM-CSF production and the presence of CD34+ cells within primary HNSCC would translate into increased recurrence, metastasis or cancer-related death during the 2 years following surgical excision. Freshly excised primary HNSCC of 20 patients that subsequently developed disease, and of 17 patients that remained with no evidence of disease were analyzed for production of GM-CSF and for CD34+ cell content. The cancers of patients that subsequently developed recurrences or metastatic disease produced almost 4-fold the levels of GM-CSF and had approximately 2.5-fold the number of CD34+ cells as did cancers of patients that remained disease-free. In a second method of analysis, the prognostic significance of high vs. low GM-CSF and CD34+ cell values was evaluated. These analyses showed that patients whose cancers produced high GM-CSF levels or had a high CD34+ cell content had a disproportionately high incidence of recurrence or metastatic disease (94% and 100%, respectively), while the majority of patients whose primary cancers produced low levels of GM-CSF or had a low CD34+ cell content remained disease-free (16% and 19%, respectively). Our results indicate that the presence of CD34+ cells in GM-CSF-producing HNSCC is associated with a poorer prognosis for the cancer patients and suggest the utility of these parameters as prognostic indicators of outcome. Mechanistically, our results suggest that the presence of immune suppressive CD34+ cells in GM-CSF-producing HNSCC leads to increased tumor recurrence or metastasis.

Adult↗
PubMed1997

Perioperative strategies in the management of carotid body tumors.

Despite the availability of noninvasive neuroradiographic techniques for the evaluation of head and neck neoplasms, paragangliomas of the carotid body often achieve substantial size before definitive diagnosis. Surgical "exploration" for the attempted resection of these lesions often results in significant blood loss, inadvertent cranial nerve injury, and procedure abandonment with partial tumor removal. Sixteen carotid body tumors were surgically resected at our institution between July 1988 and January 1995. Four of these patients had undergone cytologic examination by fine-needle aspiration (FNA) and another 6 patients underwent failed attempted resection of their lesions as the result of intraoperative hemorrhage. Of the remaining 6 patients referred for the first time evaluation of a "neck mass," the diagnosis was made by patient history, physical examination, magnetic resonance imaging, or magnetic resonance angiography. Complete tumor removal was accomplished in all 16 patients using a variety of lateral transcervical and skull base approaches. This article focuses on the clinicoradiographic diagnosis of carotid body tumors that do not need preoperative histologic confirmation. Specific intraoperative techniques for tumor removal, carotid artery management, and cranial nerve preservation are demonstrated through case presentations. Perioperative morbidity and overall results are detailed for this series of patients.

Adult↗
PubMed1997

Ondansetron versus droperidol or placebo when given prophylactically for the prevention of postoperative nausea and vomiting in patients undergoing middle ear procedures.

STUDY OBJECTIVE: To compare the prophylactic administration of ondansetron with droperidol or placebo to determine its effectiveness in reducing postoperative nausea and vomiting after middle ear procedures. DESIGN: Prospective, randomized, double-blind study. SETTING: Inpatient otolaryngology service at a university medical center. PATIENTS: 120 ASA physical status I and II patients presenting for elective middle ear surgical procedures. INTERVENTIONS: Patients were randomly assigned to receive either placebo (Group 1), ondansetron 4 mg intravenously (IV) (Group 2), or droperidol 25 mcg/kg i.v. (Group 3) 10 minutes before induction of general anesthesia using thiopental 5 mg/kg i.v. with fentanyl 2 mcg/kg i.v. and maintenance anesthesia with isoflurane 1% to 2% end-tidal in a 50% air/oxygen mixture. MEASUREMENTS AND MAIN RESULTS: Total surgical, anesthesia, extubation, and postanesthesia care unit (PACU) occupancy times were recorded along with anesthesia recovery scores. The incidence and severity of nausea, vomiting, and pain along with rescue antiemetic administration, also were recorded. Similar assessments were made over the next 24 hours. Intergroup demographic data were similar except that the male to female ratio was higher in the ondansetron group. Stewart scores, reflecting emergence from anesthesia, were higher with ondansetron compared with droperidol. The incidence of nausea was similar between the groups but the severity was less after ondansetron therapy. More patients vomited after placebo than when given either droperidol or ondansetron. No intergroup differences were noted in the use of rescue antiemetics. Twenty-four hours later, more patients who received the placebo drug had nausea or vomited compared with either ondansetron or droperidol. CONCLUSIONS: Ondansetron 4 mg i.v. is as effective as droperidol and better than placebo in preventing nausea and vomiting in patients undergoing middle ear surgery. No cost advantage as determined by lower use of rescue antiemetics or shorter PACU times was noted after the prophylactic administration of ondansetron.

Adult↗
PubMed1997

Intracranial complications of temporal bone osteoradionecrosis.

OBJECTIVE: To present four cases of life-threatening intracranial complications associated with temporal bone osteoradionecrosis. STUDY DESIGN: This study was a retrospective case review of four patients combined with a literature review. SETTING: All patients were treated at Loyola University Medical Center, which is a tertiary care facility. PATIENTS: The four patients were retrospectively reviewed without demographic constraints. INTERVENTIONS: All patients underwent preoperative radiographic assessment (magnetic resonance imaging/computed tomography scan), and three of the four patients underwent surgery. MAIN OUTCOME MEASURE: The role of surgical intervention in the management of advanced temporal bone osteoradionecrosis. RESULTS: Three patients underwent mastoid surgery after medical treatment of intracranial complications associated with temporal bone osteoradionecrosis. All three patients had dry, epithelialized mastoid cavities. One patient died as a result of meningitis. CONCLUSIONS: Mastoid surgery should be used in the overall management of patients with advanced temporal bone osteoradionecrosis to prevent secondary intracranial complications.

Adult↗