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Biomedical subjects

Lee A Zimmer

Publications and source records attributed to Lee A Zimmer.

9 recordsLinked to original sources
PubMed2007

Expanded endonasal approach: a fully endoscopic completely transnasal resection of a skull base arteriovenous malformation.

OBJECTIVE AND IMPORTANCE: Vascular lesions with an intraosseus nidus involving the skull base are uncommon and challenging [Gianoli GJ, Amedee RG Vascular malformation of the sphenoid sinus. Ear Nose Throat J. 70:373-375;(1991), Malik GM, Mahmood A, Mehta BA Dural arteriovenous malformation of the skull base with intraosseous vascular nidus. Report of two cases. J. Neurosurg 81:620-623;(1994)]. We present a pediatric patient, with a life-threatening arteriovenous malformation (AVM) of the sphenoid sinus, clivus, and ventral skull base, who failed routine multimodality management of AVMs. An entirely transsphenoidal fully endoscopic resection was used to resect this ventral cranial base AVM with an intraosseus nidus located in the clivus. CLINICAL PRESENTATION: A 4-year-old female presented with recurrent, life-threatening hemorrhages from a clival and ventral skull base AVM of the entire clivus and ventral skull base. The patient had been temporized from the age of 2-4 years with multiple internal and external carotid arterial particulate and alcohol embolizations, including both external and internal carotid artery embolizations, intracranial ligation of the right internal carotid artery, and gamma knife irradiation. Despite these multiple interventions, the patient had persistent, life-threatening hemorrhages from arterial recanalization and recruitment requiring intubation, tracheostomy, and nasopharyngeal packing. INTERVENTION: The patient underwent a three-stage surgical intervention to resect the AVM. An open subfrontal approach, as the first procedure, provided minimal access to the feeding vessels and was therefore aborted. A two-stage image-guided fully endoscopic approach via a sublabial midface approach without external incisions was performed. Postoperative angiography revealed minimal residual shunting in the pharynx and cavernous sinus. The patient has been free of significant hemorrhages over the past three years. CONCLUSION: Technological advances in endoscopic surgery and image guidance are now allowing for purely endoscopic surgical treatment of previously unresectable lesions with acceptable morbidity. We report the successful and safe resection of a ventral cranial base AVM via a fully endoscopic approach. This paper reports the first AVM with a purely intraosseus nidus of the ventral skull base and demonstrates the ability to deal with complex ventral skull base lesions using a fully endoscopic transsphenoidal technique.

Cerebral Angiography↗
PubMed2006

Resection of a recurrent paraganglioma via an endoscopic transnasal approach to the jugular fossa.

OBJECTIVE: To present a novel endoscopic, transnasal approach to a recurrent paraganglioma of the jugular fossa (glomus jugulare). STUDY DESIGN: Case report and review of the literature. SETTING: The study was carried out at the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, U.S.A. PATIENT: A 64-year-old woman presented to the University of Pittsburgh Medical Center with a 9-month history of left otalgia, occasional vertigo, facial pain, and recurrent epistaxis. She had undergone two previous procedures over the past 35 years for a glomus tympanicum. Physical examination revealed a mass in the left nasopharynx originating from the eustachian tube. A computed tomographic scan revealed an expansive mass in the left jugular foramen extending into the posterior parapharyngeal space suggestive of a large jugular paraganglioma. INTERVENTION: The patient underwent preoperative embolization of the paraganglioma. An endoscopic, transnasal approach along the eustachian tube, the ascending parapharyngeal carotid artery, and into the jugular fossa was used to remove the tumor. Intraoperative image guidance assisted in the identification of key anatomic landmarks. RESULTS: Postoperative magnetic resonance imaging revealed a thin rim of enhancement at the posterior aspect of the jugular fossa consistent with residual tumor. The patient was discharged to home on postoperative Day 1 in stable condition. There have been no complications with 4 months of follow-up, and the left facial paralysis secondary to preoperative embolization has resolved. CONCLUSION: We report the successful subtotal resection of a recurrent paraganglioma via a novel endoscopic, transnasal, transclival, transpetrous approach with image guidance. This approach allowed the near-total resection of a recurrent glomus jugulare with minimal surgical morbidity. Technological advances and surgical experience with nasal endoscopy and image guidance allow minimally invasive surgical management of select extracranial lesions of the lateral cranial base.

Embolization, Therapeutic↗
PubMed2006

Base of tongue schwannoma: a case report.

Both malignant and benign lesions may be found on the base of the tongue, including metastasis from other sites. Various surgical approaches to the base of tongue have been described. Here, we report a case of a 26-year-old woman with a schwannoma in the base of tongue removed through a suprahyoid pharyngotomy approach. The biology and pathology of schwannoma in the oral cavity are discussed. The advantage of the suprahyoid pharyngotomy approach for complete excision of a mass in the base of tongue is demonstrated.

Adult↗
PubMed2005

Current use of 18F-fluorodeoxyglucose positron emission tomography and combined positron emission tomography and computed tomography in squamous cell carcinoma of the head and neck.

The history and physical examination, computed tomography (CT) and magnetic resonance imaging are the cornerstones for identifying new and recurrent cancers of the head and neck. The advent of positron emission tomography (PET) and combined PET/CT imaging technology is a promising development. These modalities have the potential to help stage patients presenting with head and neck cancer, identify responses to nonsurgical therapy, and allow earlier detection of recurrence in the hope of improving survival. The following paper provides a brief history of PET and PET/CT imaging. The current PET and PET/CT literature for squamous cell carcinoma of the head and neck is reviewed, and specific recommendations for its use are provided.

Carcinoma, Squamous Cell↗
PubMed2005

Head and neck malignancy: is PET/CT more accurate than PET or CT alone?

PURPOSE: To prospectively determine whether combined positron emission tomography (PET) and computed tomography (CT) is more accurate than either PET or CT alone in depicting malignant lesions in the head and neck. MATERIALS AND METHODS: Study was approved by the institutional review board, and patient informed consent was waived. Sixty-five consecutive patients (42 men, 23 women; age range, 43-83 years) known to have or suspected of having head and neck cancer were examined with combined PET/CT. CT was performed with intravenous administration of a contrast agent, and the CT data were used for attenuation correction. Each examination was interpreted in three ways: PET images in the absence of CT data, CT images in the absence of PET data, and fused PET/CT images. Probability of malignancy of each lesion was assigned a score by using a five-point scale. Receiver operating characteristic (ROC) analyses were performed by using biopsy, imaging, or clinical follow-up as the reference standard. The minimum follow-up was 6 months (range, 6-12 months). The results were additionally analyzed to assess the degree of radiologist confidence. RESULTS: Follow-up was available for 64 (98%) of 65 patients. ROC analyses demonstrated that PET/CT is significantly superior to PET or CT alone for depiction of malignancy in the head and neck (P < .05). In this series, PET/CT had a sensitivity of 98%, a specificity of 92%, and an accuracy of 94%. Radiologist confidence was substantially higher with the combined modality. CONCLUSION: Combined PET/CT is more accurate than PET or CT alone for the depiction of malignancy in the head and neck. Radiologist confidence is improved with the combined modality.

Adult↗
PubMed2005

The use of combined PET/CT for localizing recurrent head and neck cancer: the Pittsburgh experience.

We performed a retrospective study of 47 patients to ascertain the ability of combined positron-emission tomography and computed tomography (PET/CT) to localize recurrent head and neck cancer. When clinically warranted, biopsies were performed in an attempt to obtain pathologic confirmation of the PET/CT findings. Of the 47 patients, 33 exhibited PET/CT findings consistent with recurrent cancer. Of the 33 patients, 25 underwent either biopsy or surgical excision of disease in an attempt to obtain a pathologic confirmation. Biopsy analysis confirmed the PET/CT findings in 22 of these patients; in the remaining 3 patients, pathologic findings were inconsistent with the PET/CT diagnosis. Based on the subset of 25 patients who underwent pathologic testing, the sensitivity of combined PET/CT was 95% and the specificity was 60%. We conclude that combined PET/CT imaging is a valuable tool for localizing tumor recurrence in patients with head and neck cancer.

Aged↗
PubMed2004

Sources of registration error with image guidance systems during endoscopic anterior cranial base surgery.

OBJECTIVES: The goal of this study was to evaluate the accuracy of the registration process and to identify potential sources of error during anterior cranial base surgery. STUDY DESIGN AND SETTING: The registration accuracy of image guidance and the location of excluded fiducials were recorded prospectively from 50 endoscopic, anterior cranial base procedures in an academic university setting. RESULTS: The mean error of initial registration was 2.8 mm (range, 1.4 to 7.1 mm). Following the exclusion of fiducials the mean error of registration was 1.6 mm (range, 0.6 to 3.7 mm). There was a significant improvement in the mean error rate from initial to final registration following the exclusion of fiducials (P < 0.0001). Posterior fiducials were excluded most often and anterior fiducials were excluded the least. Registration accuracy was similar for CT and MRI (P = 0.64). CONCLUSIONS: The accuracy of the Stryker Image Guidance System is enhanced by the exclusion of individual fiducials with high registration errors. SIGNIFICANCE: The exclusion of fiducials with high registration errors increases the accuracy of image guidance in anterior cranial base surgery.

Aged↗
PubMed2003

Combined positron emission tomography/computed tomography imaging of recurrent thyroid cancer.

OBJECTIVE: The study goal was to evaluate the use of combined positron emission tomography/computed tomography (PET/CT) imaging for localization of recurrent disease in thyroid cancer patients. STUDY DESIGN AND SETTING: Eight patients with suspected recurrence of thyroid cancer on the basis of elevated serum thyroglobulin or calcitonin levels underwent combined PET/CT imaging on a prototype device. All 8 patients had previously undergone total thyroidectomy and (131)I ablation for thyroid carcinoma. Patients with papillary carcinoma had negative (131)I scans. RESULTS: Eight patients underwent combined PET/CT scanning. Four (50%) of 8 patients underwent PET/CT indicating recurrence in the head and neck. A total of 11 lesions in these 4 patients were suspicious for recurrence on combined PET/CT imaging. Three patients with 8 lesions suspicious for recurrence on PET/CT underwent surgical removal of disease. All 3 patients had pathologic confirmation of recurrence, with 6 (75.0%) of 8 lesions being positive. CONCLUSION: Combined PET/CT imaging is a valuable tool for the diagnosis and anatomic localization of recurrent thyroid cancer.

Adult↗