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Biomedical subjects

M Arriaga

Publications and source records attributed to M Arriaga.

18 recordsLinked to original sources
PubMed1996

Enhanced retrosigmoid exposure with posterior semicircular canal resection.

A subset of patients with acoustic neuromas and useful hearing have tumors that are inadequately approached by both middle fossa and retrosigmoid techniques. The enhanced retrosigmoid technique combines the hearing preservation of posterior semicircular canal ablation to achieve lateral internal auditory canal exposure with the ample cerebel-lopontine angle exposure of the standard retrosigmoid technique.

Cerebellopontine Angle↗
PubMed1993

Acoustic neuroma volume: MRI-based calculations and clinical implications.

This study developed a technique for magnetic resonance imaging (MRI)-based volume calculation and defined the specific volume-diameter relationship in acoustic neuromas (AN). Computer-assisted measurement calculated the area of tumor in each MRI slice. Volume was determined by multiplying area by slice interval. The technique was validated by imaging known volumes of gadolinium. The precision was greater than 95%. Our volume calculations revealed a specific volume-diameter relationship in ANs. The following conclusions can be drawn: 1. our technique can accurately determine AN tumor volume; 2. the AN volume-diameter relationship is a specific function and cannot be predicted by assumptions of tumor shape; 3. the volume-diameter relationship should be combined with clinical data to determine the "break point" at which small increments of diameter produce significant clinical sequelae.

Humans↗
PubMed1992

Selection of surgical approaches for meningiomas affecting the temporal bone.

The varied locations of meningiomas within the temporal bone require a wide array of neurotologic approaches to accomplish complete resection with minimal morbidity. We reviewed 56 consecutive patients with temporal bone meningiomas. The six surgical approaches are described with regard to site of lesion, morbidity of procedure, and long-term patient outcome. Recommendations are made for selection of surgical approach. Hearing preservation was attempted in 25%. Middle fossa tumor removal was performed in nine patients (16%), retrosigmoid (suboccipital) in five patients (9%), translabyrinthine in 24 patients (43%), transcochlear in 15 patients (27%), infratemporal fossa in two patients (4%), and retrolabyrinthine in one patient (2%). Overall, meningioma surgery has higher morbidity, poorer facial nerve outcome, and higher recurrence rates than acoustic neuroma surgery. Thirteen percent of patients were unable to resume full preoperative activities after their surgery. Facial nerve transection occurred in 9% of the cases, and 83% of cases with more than 1 year followup had satisfactory or intermediate facial function (grades I to IV). Meningiomas of the temporal bone are insidious and aggressive lesions. Particular care is required to select the surgical approach appropriate for location, level of hearing, and the anatomic structures involved. Patients must be realistically counseled about the surgical morbidity and long-term outcome associated with each approach.

Facial Nerve↗
PubMed1992

Hearing preservation following surgical removal of meningiomas affecting the temporal bone.

It is a common clinical impression that preservation of hearing is more often achieved when removing a meningioma than a similarly sized acoustic tumor. However, relatively few reports have focused on postoperative hearing results after meningioma removal, and detailed audiometric data are not commonly provided, particularly in the neurosurgical literature. During the past 16 years, 56 meningiomas affecting the temporal bone have been surgically removed at the House Ear Clinic. Hearing preservation was attempted in 16 (29%) of the 56 cases, and these were the focus of this study. The primary presenting symptom was otologic in 67% of these cases, including hearing loss as the primary symptom in 27%. Measurable postoperative hearing was present in 11 (92%) of 12 patients with postoperative audiograms available, and 8 (67%) of 12 patients had good hearing postoperatively. Hearing was preserved near the preoperative level (within 10 dB speech reception threshold and 15% speech discrimination) in 75% of cases.

Aged↗
PubMed1991

The role of preoperative CT scans in staging external auditory meatus carcinoma: radiologic-pathologic correlation study.

Survival is related to the pathologic extent of tumor in external auditory meatus (EAM) carcinoma. This study assesses the validity of preoperative CT scans in staging EAM carcinoma. The accuracy of staging EAM carcinoma with preoperative CT scans was evaluated by comparing radiography and histopathology. Patients who received preoperative CT scan were selected from a retrospective series of 35 temporal bone resections for EAM squamous cell carcinoma. The CT scans were systematically reviewed for tumor involvement in 12 anatomic areas. The histopathology slides for the corresponding patients were reviewed according to the same criteria. CT scan findings accurately diagnosed the extent of tumor involvement identified during histopathologic examination. These tumors demonstrated the capacity to spread along existing anatomic pathways as well as direct bone erosion. We conclude that preoperative CT scans accurately stage EAM squamous cell carcinoma.

Carcinoma, Squamous Cell↗
PubMed1990

Otolaryngologic management of posttransplant lymphoproliferative disease in children.

Twelve of 14 children (86%) given a pathologic diagnosis of posttransplantation lymphoproliferative disease (PTLD) at the Children's Hospital of Pittsburgh presented with head and neck symptoms, and are included in this retrospective analysis. Upper airway obstruction was the most common symptom, evident in nine children (75%). Ten children (83%) had febrile illnesses with dysphagia, odynophagia, and evidence of hypertrophy of components of Waldeyer's ring. Associated findings included cervical adenopathy, sinusitis, and otitis media. The two remaining children had an intratracheal and paratracheal mass, respectively. Excision of obstructing lymphoid tissue with proper handling of the specimen is advocated for diagnosis and relief of airway obstruction. Systemic therapy is necessary for treatment of PTLD and includes reduction of immunosuppression. Erythromycin causes elevation in cyclosporine levels and should be avoided in patients taking this drug.

Adolescent↗
PubMed1990

Staging proposal for external auditory meatus carcinoma based on preoperative clinical examination and computed tomography findings.

An accepted staging system for squamous cell carcinoma of the external auditory meatus is currently lacking and would permit accurate comparison of treatment strategies and results for patients with this unusual neoplasm. In order to develop such a staging system we reviewed the prognostic variables and the accuracy of radiographic diagnosis in 39 patients undergoing temporal bone resection for squamous carcinoma of the external auditory meatus. Predictors of poor survival were extensive tumor involvement, facial nerve paralysis, middle ear involvement, and cervical or periparotid lymphadenopathy. In a comparison of 12 specific anatomic sites, computed tomography was found to be an accurate indicator of histopathologically proven tumor invasion. On the basis of this clinical radiographic-histopathologic analysis, we propose a TNM staging system for external auditory meatus carcinoma utilizing preoperative computed tomography and physical examination. This system fulfills the requirements of the American Joint Committee on Cancer that a staging system should provide a sound basis for therapeutic planning for cancer patients by describing the survival and resultant treatment of different patient groups in comparable form.

Aged↗
PubMed1990

Facial translocation: a new approach to the cranial base.

Nasopharynx, clivus, and cavernous sinus are difficult regions of the cranial base in which to perform oncologic surgery. We have developed an approach to this area by using facial soft tissue translocation and craniofacial osteotomies. Surgical field obtained at the skull base can extend from the contralateral eustachian tube to ipsilateral geniculate ganglion. It includes the nasopharynx, clivus, sphenoid, and cavernous sinus, as well as the entire infratemporal fossa and superior orbital fissure. Our experience with this technique in 12 patients is reported. All patients healed primarily.

Face↗
PubMed1989

Squamous cell carcinoma of the external auditory meatus (canal).

A retrospective study of 35 patients with squamous cell carcinoma of the external auditory meatus treated at the Eye and Ear Hospital of the University of Pittsburgh was performed. The standard treatment was a temporal bone resection that corresponded to the extent of the lesion, followed by postoperative radiation therapy. The tumor extensions, symptoms, treatments, survival rates, and prognostic variables were reviewed. Overall, 12 of 35 patients survived. Lesions limited to the external auditory meatus with no erosion had excellent prognoses. Survival in intermediate lesions with bony erosion or middle ear involvement was related to the status of surgical margins after partial or subtotal temporal bone resections. Extensive lesions that involved the surrounding soft tissue or dura had poor prognoses. The survival value of total temporal bone resection remains unproved.

Aged↗
PubMed1987

Interrelationship between mitosis and endomitosis in cultures of human megakaryocyte progenitor cells.

Sera from dogs rendered aplastic by total-body irradiation stimulate human bone marrow megakaryocyte progenitors to form megakaryocyte colonies in plasma clot cultures. In this investigation, we evaluated the effects of varying concentrations of such sera on both the mitotic and endomitotic phases of human megakaryocyte development in vitro. When low concentrations of aplastic canine sera (2.5% to 5.0% [vol/vol]) were added to cultures of human peripheral blood mononuclear cells in place of normal AB serum, megakaryocyte colony formation was augmented fivefold, cell numbers per colony increased approximately 2.5-fold, and the geometric mean megakaryocyte ploidy almost doubled. Further increasing the aplastic canine serum concentration from 10% to 30% (vol/vol) stimulated no additional colony formation. However, there was a further augmentation of cell numbers per colony associated with a progressive decrease in the mean megakaryocyte ploidy. Megakaryocyte cultures were harvested after 7, 12, 15, and 19 days of incubation, and these demonstrated that the lower mean ploidy values found at the higher concentrations of aplastic canine serum did not result from delayed endoreduplication. At all aplastic serum concentrations evaluated, there existed a strong correlation between nuclear ploidy and cell diameter. We conclude that both the mitotic and endomitotic events in human megakaryocytopoiesis may be influenced by a factor or factors present in aplastic canine serum. At lower in vitro concentrations, such sera stimulate both mitosis and endomitosis, which promotes the development of megakaryocyte colonies composed of larger cells with a higher mean ploidy. With increasing aplastic serum concentrations, colony formation plateaus and mitosis is favored over endomitosis. This results in colonies composed of more numerous but smaller megakaryocytes with a lower mean ploidy. Our data suggest that the size and extent of polyploidization that can be achieved by a developing megakaryocyte may be influenced by the mitotic prior history of its immediate precursor cell.

Adult↗