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Biomedical subjects

S G Harner

Publications and source records attributed to S G Harner.

At least 37 records · Page 2Linked to original sources
PubMed1993

Acoustic neuroma and pregnancy.

From January 1978 through July 1989, 360 patients underwent primary removal of an acoustic neuroma at the Mayo Clinic. Seventy of these patients were women under the age of 46 years; six of them were pregnant between the time of onset of their symptoms and the removal of their tumor. A review of the records of these six women revealed the presenting complaint in most to be central neurologic symptoms rather than labyrinthine symptoms. All had unilateral tumors. These tumors tended to be larger and more vascular than those in the nonpregnant cohort, and to have greater surgical morbidity. The pure-tone hearing levels were normal in four of these patients. All women experienced normal vaginal delivery without complication. Based on our experience with these women, we believe that acoustic neuroma present during pregnancy may be managed by close observation until the postpartum period, provided there are no impending neurologic complications.

Adolescent↗
PubMed1993

Does the distribution of Schwann cells correlate with the observed occurrence of acoustic neuromas? .

Acoustic neuromas account for 75 to 80 percent of cerebellopontine angle tumors and 8 to 10 percent of all intracranial neoplasms. These tumors arise from the Schwann cell sheath that surrounds the peripheral portion of the facial, cochlear, superior, and inferior vestibular nerves. Theoretically, a schwannoma may arise from Schwann cells anywhere along these nerves from the glial-Schwann cell junction to the end organ. Clinically, however, they most frequently originate from the vestibular nerves, occasionally from the facial, and only rarely from the cochlear nerve. This investigation utilized light microscopy, immunochemistry, and digital optical morphologic analysis to determine the distribution of Schwann cells along the facial and vestibulocochlear nerves in an attempt to explain the observed distribution of tumors, and to evaluate currently accepted theories. No direct correlation between the distribution of Schwann cells and the observed distribution of schwannomas was found. Thus, this study did not confirm the currently held theories regarding schwannoma distribution in these nerves.

Cell Count↗
PubMed1992

Effect of BAEP monitoring on hearing preservation during acoustic neuroma resection.

We measured the effect of brainstem auditory evoked potential (BAEP) monitoring on hearing preservation in acoustic neuroma resection in 90 consecutive patients with monitoring compared with 90 historical controls matched for tumor size and preoperative hearing status. In small tumors (less than 2 cm), BAEP monitoring was associated with a higher rate of hearing preservation and a greater chance that the hearing preserved was clinically useful. Changes in the BAEP intraoperatively showed a good correlation with postoperative hearing status.

Evoked Potentials, Auditory, Brain Stem↗
PubMed1992

Current results of the retrosigmoid approach to acoustic neurinoma.

Since 1984 when cranial nerve monitoring became routinely performed at the Mayo Clinic, 255 patients have undergone 256 procedures using the retrosigmoid approach for the removal of acoustic neurinomas. Of these, 221 patients had some hearing before surgery and 52 maintained hearing following surgery. The anatomical continuity of the facial nerve was preserved in 237 of these 256 procedures. It was possible to perform a primary end-to-end anastomosis in seven of the remaining 19 patients, and one patient had a cable graft inserted. Thus, 95.7% of these patients were believed to have potential for spontaneous facial nerve function. Of the 11 patients in whom this was not possible, seven underwent early spinal accessory facial anastomosis, in two hypoglossal-facial anastomosis was performed, and two had no facial nerve procedures and have paralysis of the facial nerve. There were two deaths from a pulmonary embolus in the early postoperative period, both 4 days following otherwise uneventful surgery. The most common postoperative complication was cerebrospinal fluid leakage, which has not resulted in significant permanent morbidity although early repair for this problem is now routinely recommended. Other complications were quite rare and have generally not resulted in any major change in patient lifestyle or activity level. This review reconfirms that the retrosigmoid surgical treatment of acoustic tumors continues to be an acceptable treatment option.

Adolescent↗
PubMed1991

Auditory monitoring during acoustic neuroma removal.

Preservation of hearing has become attainable for patients with small acoustic neuromas. Brain-stem auditory evoked response was monitored intraoperatively in 60 patients undergoing acoustic neuroma surgery via the posterior fossa approach. The overall rate of hearing preservation was 30% in the monitored group and 20% in 60 patients who were matched for tumor size and preoperative hearing level and underwent the same surgical procedure but without intraoperative brain-stem auditory evoked response monitoring. The rate of hearing preservation was correlated with tumor size: with tumors less than or equal to 1 cm, hearing was preserved in 82% of monitored and 36% of unmonitored patients; hearing was not preserved with tumors larger than 3 cm. Intraoperative brain-stem auditory evoked response monitoring appears to have improved the preservation of hearing during removal of small tumors.

Adolescent↗
PubMed1991

Longitudinal followup of patients with Menière's disease.

The etiology, pathophysiology, and natural history of Menière's syndrome are poorly understood. The reported studies have had inadequate followup or insufficient numbers of patients to allow conclusions about the natural history. Our study group was 119 patients who had the classic symptom complex of episodic vertigo, tinnitus, and hearing loss in the year 1970. After initial review of these charts, follow-up information was obtained by questionnaire, telephone interview, chart review, or repeat examination, when possible, both in 1983 and in 1988, for a total followup of 18 years. In the patients with followups of at least 14 years, vertiginous episodes had disappeared completely in 50% of patients and somewhat resolved in 28%; hearing was absent in 48% and worse in 21%. Surprisingly, 43% of patients underwent surgery at some point for control of vertigo. Bilateral disease was present initially in 13% and developed subsequently in 45% of patients. Other areas reviewed included the efficacy of long-term medical treatment, frequency and severity of vertiginous attacks, and contralateral ear symptoms.

Adult↗
PubMed1990

Preoperative and postoperative auditory brain-stem response results for patients with eighth-nerve tumors.

Preoperative and postoperative auditory brain-stem response results and audiologic data were reviewed for seven patients whose hearing was preserved after eighth-nerve tumor surgery. Auditory brain-stem response absolute latencies (I, III, and V) and interpeak intervals (I-III, III-V, and I-V) were identified more often postoperatively than preoperatively. Even though postoperative absolute latencies were usually abnormal, the interpeak intervals were usually normal following surgery. Postoperative hearing sensitivity was unchanged or slightly poorer for five of the seven patients, but postoperative speech discrimination was the same or better for six of the seven patients. All three patients having acoustic reflex testing showed improvement postoperatively.

Adult↗
PubMed1990

Retrosigmoid removal of acoustic neuroma: experience 1978-1988.

The need to preserve hearing during acoustic neuroma removal has rekindled interest in labyrinth-sparing procedures. This review of 11 years' experience with the retrosigmoid approach to acoustic neuroma removal includes 335 procedures in 332 patients. There were no intraoperative deaths; two patients died in the postoperative period. The facial nerve was preserved in 86.3% of procedures, and auditory function was preserved in 45 procedures (34% of those tumors were 2 cm or smaller). Postoperative complications occurred in 101 procedures, the most common being cerebrospinal fluid otorhinorrhea in 40 cases; 25 of these required secondary surgery. Meningitis occurred 16 times and aspiration 8 times; all other complications were less frequent. Tumor removal was incomplete in eight procedures; in only one of these cases has tumor recurred. The six recurrences usually were identified 5 or more years postoperatively. This has prompted us to follow patients for 7 years postoperatively. Major changes in our management include the use of the supine position and of electrophysiologic monitoring. Advantages of the approach are: (1) wide access to the tumor, (2) applicability to all tumor sizes, (3) potential to preserve facial and auditory function in all cases, and (4) ability to change procedure without sacrificing labyrinth. This review confirms our confidence in this approach to acoustic neuroma removal.

Adolescent↗
PubMed1990

[Auditory brainstem response in the aged and elderly].

Auditory brainstem response(ABR) was studied in 63 old healthy individuals (mean age = 66.42 +/- 9.88 years). They presented some degree of hearing loss (pure tone hearing threshold for 4 frequencies less than or equal to 30dB HL). Meanwhile 24 younger subjects (half for each sex, mean age = 17.61 +/- 2.63 years) with normal hearing were chosen as the control group. It was found that (a) the older group had greater mean values for both absolute peak latencies and inter-peak latencies than the younger group. The results indicate that age-related hearing loss is due to cochlear pathology but do not exclude the possibility of central auditory involvement. (b) the main parameters of ABR in both ears for each individual were quite symmetric. This fact implicates the diagnostic significance in differentiating presbycusis and space occupying lesion in the brainstem. (c) sex also affected the ABR in both age groups. Males were easier to be affected than females.

Aged↗
PubMed1988

Mast cell pharyngitis as a cause of supraglottic edema.

A 30-year-old nonatopic woman had experienced a 9-year history of persistent symptoms of supraglottic edema. She had previously undergone epiglottectomy and excision of redundant left arytenoid tissue to improve her breathing and dysphagia. Uvular tissue was removed surgically at our clinic for histopathological examination of the excised tissues. This revealed diffuse infiltration by mast cells, many of which appeared degranulated. Uvular tissue from control patients undergoing uvulopalatopharyngoplasty for obstructive sleep apnea contained significantly fewer mast cells per high power field. To our knowledge such a degree of mast cell infiltration into supraglottic tissues has not been reported previously or associated with clinical symptoms.

Adult↗
PubMed1988

The effect of fibrin tissue adhesive on the middle and inner ears of chinchillas.

The purpose of this study was to examine potential toxic effects of fibrin tissue adhesive to the middle and inner ears. Using the chinchilla as our experimental model, we placed fibrin sealant on either the footplate or the round window membrane in one ear, and placed similar amounts of normal saline in the same area of the opposite ear. In addition, the fibrin adhesive was used to anchor a fascia lata graft for myringoplasty. Both fibrin adhesive and normal saline produced mild reactions in the middle and inner ears when they were placed on the round window membrane; little reaction occurred when fibrin adhesive was placed on the oval window or when it was used for myringoplasty.

Animals↗
PubMed1988

Intraoperative monitoring of the facial nerve.

Anatomic preservation of the facial nerve, with maximal facial function, is one of the goals of acoustic neuroma surgery. Application of electrophysiologic monitoring techniques is useful in achieving this goal. Preoperative electromyography and nerve conduction studies provide important prognostic information for preservation of the nerve and postoperative function. Intraoperative electromyography alerts the surgeon to facial nerve proximity and potential injury. Direct nerve stimulation is utilized to confirm the location and integrity of the nerve. Matched-pair analysis of two groups of patients demonstrated an increased ability to preserve the facial nerve with less postoperative facial deformity.

Adolescent↗
PubMed1987

Improved preservation of facial nerve function with use of electrical monitoring during removal of acoustic neuromas.

Continuous spontaneous electromyographic activity and responses to electrical stimulation of the facial nerve in the surgical field were monitored in 48 patients undergoing primary removal of an acoustic neuroma. The operative and postoperative results in these patients were compared with the results in 48 patients who were matched for age and size of tumor and who underwent the same surgical procedure without intraoperative monitoring. Eighty-three percent of the patients had preoperative evidence of facial neuropathy, which was more severe with larger tumors. Postoperative facial nerve function was most accurately predicted on the basis of the extent of facial neuropathy on preoperative electrophysiologic testing. Anatomic preservation of the facial nerve in patients with large tumors was substantially improved in the monitored patients (67%) in comparison with those without monitoring (33%). No difference was noted in facial nerve function in the two groups of patients immediately postoperatively. By 3 months, the degree of improvement in the monitored group exceeded that in those who were not monitored, particularly in patients with medium-sized and large tumors.

Adult↗
PubMed1987

Peripheral labyrinthine causes of dizziness.

A patient's complaint of dizziness must be defined specifically. Many dizzy patients do not have labyrinthine or balance system disease. The patient with dysequilibrium, on the other hand, often has a balance system disease but not necessarily a labyrinthine disorder. The patient with vertigo most likely has labyrinthine disease. Vertigo is accompanied by nystagmus, which can be identified only when the examiner specifically looks for it. Although vertigo is the classic symptom of labyrinthine disease, not all labyrinthine diseases have associated vertigo. Careful history taking, physical examination, audiometry, caloric testing, electronystagmography, and radiographic studies will identify patients with labyrinthine disorders. Treatment depends on the diagnosis. Usually it is medical, but occasionally it may be surgical. Most patients have no residual problems; a few have permanent disability.

Acute Disease↗
PubMed1987

Chondroblastoma of the skull and facial bones.

A series of 30 chondroblastomas was reviewed: 21 had occurred in the lateral part of the temporal bone, 6 in the mandible, 1 in the parietal bone, and 2 in the region that included the temporal bone and mandible. Of the 30 patients in the series, 20 were males and 9 were females; the sex of 1 patient was not stated. The ages of 29 patients ranged from 2 years 11 months to 70 years (mean, 43.5 years). Radiologic findings were not suggestive of a specific diagnosis, although the lesions appeared to be benign. Histologically, most tumors were classic chondroblastomas. However, some showed aneurysmal bone cyst-like areas and nodules of epithelioid cells without chondroid differentiation. Conservative reexcisions were usually curative. Approximately half of the patients had recurrence after curettage.

Chondroblastoma↗
PubMed1987

Relationship of the optic nerve to the paranasal sinuses as shown by computed tomography.

Restricted exposure and inconsistencies in sinus pneumatization place the optic nerve at risk during operations on the sphenoid sinus and posterior ethmoid cells. In this study, computed tomography was used to examine these relationships. We reviewed 80 patients who underwent high-resolution computed tomographic scanning for ophthalmologic complaints in which the scan was negative. Forty-eight percent of posterior ethmoid cells are separated from the optic nerve by the thin bony lamina of the optic canal. Nearly 90% of sphenoid sinuses contact the ipsilateral optic nerve and 10% contact both nerves. Eight percent of posterior ethmoid cells override the ipsilateral sphenoid sinus and contact the optic nerve on that side. Paraxial reformatted displays allowed estimation of the degree of projection of the optic nerve into adjacent sinus cavities. Three percent of optic nerves have significant projection into the posterior ethmoid cell, and 23% project significantly into the sphenoid sinus. The width of the bony plate that separates the optic nerve from the sinus cavity was the same for sphenoid and ethmoid sinuses. Although sinus pneumatization varies among individuals, right and left sides are generally similar within one person.

Adolescent↗
PubMed1987

Residual and recurrent acoustic neuromas.

A retrospective study was conducted on all 23 patients who underwent operation for residual or recurrent acoustic neuromas during the 10-year period January 1976 through December 1985. The most common symptoms at the time of reoperation were ataxia (16 patients), facial paresthesias (13 patients), and headaches (9 patients). Primary procedures had consisted of suboccipital posterior fossa approaches in 22 patients and a middle fossa approach in one. Reoperation for recurrent or residual tumor consisted of a retrosigmoid approach in 17 patients and a translabyrinthine or translabyrinthine/retrosigmoid approach in six patients. This study confirms that residual or recurrent acoustic tumors are not common. It also suggests that long-term follow-up, for at least 7 to 8 years, is indicated.

Adult↗