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Biomedical subjects

Carl H Snyderman

Publications and source records attributed to Carl H Snyderman.

At least 19 recordsLinked to original sources
PubMed2007

Corridor surgery: the current paradigm for skull base surgery.

INTRODUCTION: Clival chordomas are rare tumors, especially in the pediatric population. In this report, we present the case of a 3-year-old boy who was found to have a large posterior pharyngeal, clival, and posterior fossa tumor detected on a CT scan after a closed head injury. DISCUSSION: Further questioning revealed a history of ataxia and dysphagia. Imaging confirmed severe extrinsic brain stem compression. The tumor was resected in multiple stages utilizing a minimally invasive endoscopic endonasal technique along with open transfacetal, transcondylar approach through the carotid-vertebral window. The child suffered no permanent complications as a result of our treatment and his dysphagia significantly improved. Although a complete resection was not feasible due to vascular encasement by the tumor, extensive decompression was obtained with minimal morbidity. CONCLUSION: We present this case to illustrate a new paradigm of skull base surgical approaches for large clival lesions in pediatric patients that allows aggressive resection with minimal morbidity.

Child, Preschool↗
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

A novel reconstructive technique after endoscopic expanded endonasal approaches: vascular pedicle nasoseptal flap.

BACKGROUND: In patients with large dural defects of the anterior and ventral skull base after endonasal skull base surgery, there is a significant risk of a postoperative cerebrospinal fluid leak after reconstruction. Reconstruction with vascularized tissue is desirable to facilitate rapid healing, especially in irradiated patients. METHODS: We developed a neurovascular pedicled flap of the nasal septum mucoperiosteum and mucoperichondrium based on the nasoseptal artery, a branch of the posterior septal artery (Hadad-Bassagasteguy flap [HBF]). A retrospective review of patients undergoing endonasal skull base surgery at the University of Rosario, Argentina, and the University of Pittsburgh Medical Center was performed to identify patients who were reconstructed with a vascularized septal mucosal flap. RESULTS: Forty-three patients undergoing endonasal cranial base surgery were repaired with the septal mucosal flap. Two patients with postoperative cerebrospinal fluid leaks (5%) were successfully treated with focal fat grafts. We encountered no infectious or wound complications in this series of patients. One patient experienced a posterior nose bleed from the posterior nasal artery. This was controlled with electrocautery and the flap blood supply was preserved. CONCLUSION: The HBF is a versatile and reliable reconstructive technique for defects of the anterior, middle, clival, and parasellar skull base. Its use has resulted in a sharp decrease in the incidence of postoperative cerebrospinal fluid leaks after endonasal skull base surgery and is recommended for the reconstruction of large dural defects and when postoperative radiation therapy is anticipated.

Adipose Tissue↗
PubMed2006

The expanded endonasal approach for an endoscopic transnasal clipping and aneurysmorrhaphy of a large vertebral artery aneurysm: technical case report.

OBJECTIVE: Aneurysms of the vertebral artery are rare, comprising less than 5% of all aneurysms. They can present with subarachnoid hemorrhage, medullary compression, and cranial neuropathies. In consideration of their surrounding regional anatomy, they present a formidable surgical challenge to the neurosurgeon using traditional techniques. Recent advances in endoscopic transnasal surgery have provided an additional approach for the treatment of these difficult lesions. CLINICAL PRESENTATION: We present a case of a large vertebral artery aneurysm causing mass effect on the medulla. Initial treatment consisted of endovascular trapping of the aneurysm; however, because of concerns that the remaining aneurysm and intraluminal thrombus was causing mass effect and continued brainstem compression, a decompressive procedure was required. INTERVENTION: After the endovascular trapping, the patient underwent a completely endoscopic transnasal surgical clipping and aneurysmorrhaphy. After exposure of the aneurysm, distal and proximal clips were applied transnasal, and the aneurysmorrhaphy completed using suction and ultrasonic aspiration. CONCLUSION: In consideration of their surrounding regional anatomy, aneurysms of the vertebral artery present a formidable surgical challenge to the neurosurgeon. Although endovascular techniques have proven to be extremely valuable for the treatment of these lesions, they are limited when patients have significant mass effect with brainstem compression or cranial neuropathy. Advances in endoscopic transnasal surgery have provided an additional approach for the treatment of these difficult lesions. This case report represents, to our knowledge, the first literature report of a transnasal endoscopic aneurysm clipping and thrombectomy.

Atlanto-Occipital Joint↗
PubMed2005

Expanded endonasal approach: the rostrocaudal axis. Part I. Crista galli to the sella turcica.

OBJECT: Transsphenoidal approaches have been used for a century for the resection of pituitary and other sellar tumors. More recently, the standard endonasal approach has been expanded to provide access to other, parasellar lesions. With the addition of the endoscope, this expansion carries significant potential for the resection of skull base lesions. METHODS: The anatomical landmarks and surgical techniques used in expanded (extended) endoscopic approaches to the rostral, anterior skull base are reviewed and presented, accompanied by case illustrations of each segment (or module) of approach. The rostral half of the anterior skull base is divided into modules of approach: sellar/parasellar, transplanum/transtuberculum, and transcribriform. Case illustrations of successful resections of lesions with each module are presented and discussed. CONCLUSIONS: Endoscopic, expanded endonasal approaches to rostral anterior skull base lesions are feasible and hold great potential for decreased morbidity. The effectiveness and appropriate use of these techniques must be evaluated by close examination of outcomes as case series expand.

Cranial Fossa, Posterior↗
PubMed2005

Expanded endonasal approach: the rostrocaudal axis. Part II. Posterior clinoids to the foramen magnum.

OBJECT: Transsphenoidal approaches have been used for a century for the resection of pituitary and other sellar tumors. Recently, however, the standard endonasal approach has been expanded to provide access to other parasellar lesions. With the addition of the endoscope, this expansion has significant potential for the resection of skull base lesions. METHODS: The anatomical landmarks and surgical techniques used in expanded (extended) endoscopic approaches to the clivus and cervicomedullary junction are reviewed and presented, accompanied by case illustrations of each segment (or module) of approach. The caudal portion of the midline anterior skull base and the cervicomedullary junction is divided into modules of approach: the middle third of the clivus, its lower third, and the cervicomedullary junction. Case illustrations of successful resections of lesions via each module of the approach are presented and discussed. CONCLUSIONS: Endoscopic expanded endonasal approaches to caudally located midline anterior skull base and cervicomedullary lesions are feasible and hold great potential for decreased morbidity. The effectiveness and appropriate use of these techniques must be evaluated by close examination of outcomes as case series expand.

Cranial Fossa, Posterior↗
PubMed2005

Endoneurosurgical hemostasis techniques: lessons learned from 400 cases.

The increasing popularity of minimally invasive neurosurgery has led to the development of transnasal expanded approaches for the treatment of skull base lesions. One of the greatest challenges in safely accomplishing resection of tumors, particularly intradural lesions, is effective hemostasis. Over the past 7 years the authors have progressively developed an organized approach to address this challenge. This has required the development of new instrumentation as well as variations on standard techniques. In this report they present the technique that has evolved at their institution for endoneurosurgical hemostasis.

Bone Diseases↗
PubMed2005

Evolution of reconstructive techniques following endoscopic expanded endonasal approaches.

Harvey Cushing first popularized the transsphenoidal route to the sella turcica, and Jules Hardy subsequently refined it by adding the operating microscope. Over the ensuing decades, attempts at extending the application of this approach have been advanced by Edward Laws and others. With the evolution of endoscopic approaches, the natural expansion of their use to intradural lesions followed. For the expanded endonasal approach to become a viable option, the paramount concerns surrounding consistent reconstruction of the dura mater must be overcome. In this review the authors chronicle the evolution of the reconstruction technique they currently use after performing expanded endonasal approaches. They also report the use of a balloon stent to buttress the reconstruction and counter the effects of graft migration and cerebrospinal fluid fistula formation. The technique described in this report represents an important step forward in the reconstruction of defects resulting from expanded endonasal approaches.

Endoscopy↗
PubMed2005

The management of cerebrospinal fluid leaks in patients at risk for high-pressure hydrocephalus.

OBJECTIVES/HYPOTHESIS: The transnasal endoscopic approach has become the preferred technique for the surgical management of patients with cerebrospinal fluid (CSF) leaks of the anterior, sellar, and parasellar skull base. The literature has reported an 85% to 100% success rate for the endoscopic repair of CSF leaks, which compares favorably with that reported after transcranial repair. Despite an adequate repair, a subpopulation of patients remain at high risk for recurrence of the CSF leak attributable to undiagnosed high-pressure hydrocephalus. Patients at high risk for high-pressure hydrocephalus include those who have had a subarachnoid hemorrhage as a result of trauma (accidental or surgical) or stroke and those with spontaneous CSF leaks. STUDY DESIGN: With the goal of reducing the risk of recurrence, the authors developed a protocol for the identification and management of patients with CSF leaks who are at risk for high-pressure hydrocephalus. METHODS: The protocol includes endoscopic repair, temporary CSF diversion, measurement of CSF pressure after the repair, and immediate ventriculoperitoneal shunting if necessary. RESULTS: During the period of September 1999 to April 2002, the authors repaired 25 CSF leaks through an endonasal endoscopic approach. Nineteen patients were considered at high risk for high-pressure hydrocephalus. Using the protocol described, the authors identified six patients (31%) with CSF leaks that could be associated with undiagnosed high-pressure hydrocephalus. All CSF leaks were successfully repaired using a transnasal endoscopic repair. Six patients with high-pressure hydrocephalus underwent ventriculoperitoneal shunting after repair of the CSF Leak. No recurrence has been observed at a follow-up ranging from 24 to 84 months (median period, 30 mo). CONCLUSION: Patients with high-pressure hydrocephalus may be identified in a prospective fashion to prevent recurrence or persistence of the CSF leaks. The presence or absence of high-pressure CSF may be established by means of direct CSF pressure measurement through lumbar puncture postoperatively. This allows early intervention and prevention of recurrence.

Adolescent↗
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

Teflon granuloma in the nasopharynx: a potentially false-positive PET/CT finding.

Positron emission tomography (PET) has become a critical diagnostic tool in the discovery and staging of malignancies in the head and neck. Although PET is accurate for detecting cancer, increased 18 F-fluorodeoxyglucose (FDG) uptake can be seen in healthy tissues such as muscle, fat, and glands and uptake can be seen in tissues affected by inflammation or granulomatous disease. Combined PET and CT (PET/CT) can often overcome these difficulties by fusing anatomic and physiological data, but radiographic findings of some disease processes can be confusing even with fused imaging techniques. We present two cases of FDG uptake in the posterior pharynx, localized by combined PET/CT, which was initially interpreted as squamous cell carcinoma. The increased activity was ultimately attributed to Teflon-induced granulomas. It is important for radiologists to recognize potential causes of false-positive PET/CT findings to improve our diagnostic accuracy and to avoid unnecessary biopsies and surgeries.

Aged↗
PubMed2004

Preauricular infratemporal fossa surgical approach: modifications of the technique and surgical indications.

A retrospective clinical analysis was performed to evaluate the effectiveness of the preauricular infratemporal fossa (ITF) surgical approach using modifications based on tumor pathology and extension, without compromising outcomes. Patients were surgically treated for tumors involving the ITF via a preauricular surgical approach during 1990 to 2000. Their clinical charts were reviewed to determine the association among pathological variables, details of the surgical procedure, and outcomes. Tumors in 65 patients were categorized as "malignant" and "benign." The malignant group included 44 patients (mean age, 49.5 years). Squamous cell carcinoma was the most common pathology followed by sarcomas. To achieve complete tumor resection, the ITF approach and dissection were combined with other procedures in 74% of these patients. No surgical complications were encountered in 74.4%, and a clinical cure was obtained in 55% of patients (follow-up, 2 years). The benign group included 21 patients (mean age, 36.7 years). Juvenile angiofibromas and meningiomas constituted most of the tumors in this group. An ITF approach alone was sufficient to achieve complete tumor excision in 66.7% of these patients. A clinical cure was achieved in 85% of patients (follow-up, 2 years), and 76.2% had no surgical complications. Chi-square tests revealed significant correlations between tumor extensions and surgical treatment variables. These were more evident in the malignant group, indicating the use of wider surgical exposures and more aggressive, extirpative surgery. The preauricular surgical approach to the ITF can be used to achieve a complete resection of a variety of tumors arising from or extending into the ITF. This approach can be tailored to the nature of the tumor and its extensions.

Journal Article↗
PubMed2004

Endoscopic transnasal transpterygopalatine fossa approach to the lateral recess of the sphenoid sinus.

OBJECTIVES: Lesions affecting the lateral recess of the sphenoid sinus are rarely discussed in the literature as a separate entity. This region is difficult to visualize and manipulate through the transnasal routes, especially when extensive pneumatization is present. External approaches to this area involve extensive surgery and are associated with significant morbidity. The objectives of this study are to present our experience with the endoscopic transpterygopalatine fossa approach as a method for exposing and manipulating lesions of the lateral recess of the sphenoid and to illustrate the detailed surgical steps of the procedure. STUDY DESIGN: Retrospective review. METHODS: Clinical charts of patients who had lesions originating from or extending into the lateral recess of the sphenoid sinus and who were treated at our institutions from September 1995 to June 2002 were retrospectively reviewed. All these patients were managed by the endoscopic transpterygopalatine fossa approach. RESULTS: Twelve patients (7 males and 5 females) were included in the study. Lesions included seven cerebrospinal fluid (CSF) leaks and five tumors. One patient with squamous cell carcinoma (SCC) of the sphenoid died of his disease. All CSF leaks were successfully repaired, and benign tumors were removed with good local control through the follow-up period. CONCLUSION: The endoscopic transpterygopalatine fossa approach is an excellent approach for dealing with lesions of the sphenoid lateral recess.

Adult↗
PubMed2003

Myoepithelial neoplasia of the submandibular gland: case report and therapeutic considerations.

Tumors of the submandibular gland typically arise from the seromucinous acini, which make up the majority of the gland. The most common benign tumor of this structure is the pleomorphic adenoma, whereas the most common malignancy of the submandibular gland is adenoid cystic carcinoma. We describe an unusual case of a neoplastic process of the myoepithelial cells of the submandibular gland in a middle-aged woman. This rare tumor is most commonly diagnosed in the parotid gland and in the minor salivary glands of the hard palate; a review of the literature uncovered only 5 previous reports of myoepithelioma of the submandibular gland. Distinguishing myoepithelioma from benign pleomorphic adenoma and malignant myoepithelial carcinomas can be challenging. Immunohistochemical staining can help to distinguish between the benign neoplasms, but histologic features remain the "gold standard" for diagnosing the malignant tumors. Increasing use of immunohistochemistry panels to assess parotid neoplasms also suggests that myoepithelioma may be underrecognized.

Adenoma, Pleomorphic↗
PubMed2003

Endonasal endoscopic repair of cerebrospinal fluid leaks of the sphenoid sinus.

BACKGROUND: Multiple reports have demonstrated the efficacy of the transnasal endoscopic repair of cerebrospinal fluid (CSF) leaks of the anterior cranial base. The literature, however, lacks a comprehensive clinical study specifically addressing the transnasal endoscopic repair of CSF leaks of the sphenoid sinus. OBJECTIVE: To ascertain the factors that significantly affect the surgical outcome after transnasal endoscopic repair of CSF leaks of the sphenoid sinus. METHODS: We retrospectively reviewed the medical records of all patients who underwent an endoscopic transnasal repair of CSF leaks of the sphenoid sinus at our teaching hospitals. RESULTS: Twenty-four patients with CSF leaks of the sphenoid sinuses that were repaired by the transnasal endoscopic approach were included in our study. Causes of the CSF leaks included trauma, surgery, neoplasms, and idiopathic causes. Obliteration was the most common technique used to repair the CSF fistulas (used in 15 [58%] of 26 procedures). Grafting materials included banked pericardium, mucosa, turbinate bone, and mucoperichondrium placed by underlay or onlay grafting or abdominal fat used to obliterate the sphenoid sinus. Twenty-two patients were successfully treated on the first attempt. A persistent leak in 2 patients with previously unrecognized high-pressure hydrocephalus was repaired during a second endoscopic surgery, quickly followed by ventriculoperitoneal shunting. CONCLUSIONS: Assuming an adequate repair, other factors such as the cause, the size of the defect, the technique and material used to repair the defect, and perioperative management do not affect the surgical outcome significantly. Untreated high-pressure hydrocephalus can lead to a recurrence or persistence of the leaks and should be suspected in patients with posttraumatic, idiopathic, or recurrent CSF leaks.

Adolescent↗