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Biomedical subjects

J B Newkirk

Publications and source records attributed to J B Newkirk.

9 recordsLinked to original sources
PubMed1982

Fetal treatment 1982.

Explore the source record for details and available documents.

Congenital Abnormalities↗
PubMed1982

A surgical approach to the treatment of fetal hydrocephalus.

Untreated fetal hydrocephalus results in gross cranial and facial abnormalities and profound brain damage. In an attempt to prevent both, a ventriculoamniotic shunt was implanted in a fetus with probable X-linked aqueductal stenosis and hydrocephalus. Performed at 24 weeks' gestation, the procedure used techniques similar to those used for intrauterine transfusion. After shunt placement, the fetal head size grew normally until after the 32d week, when the shunt failed. A cesarean delivery was performed at 34 weeks' gestation. The infant received a standard ventriculoperitoneal shunt after delivery, and his neonatal course has been evaluated through the first three months of life. In selected cases, the ventriculoamniotic shunt may be an acceptable treatment for fetal hydrocephalus.

Adult↗
PubMed1979

Endolymphatic sac valve implant surgery. II: The unidirectional inner ear valve implant.

A unidirectional inner ear valve implant was developed to direct excess endolymph out of the inner ear in the hydropic state (Ménière's disease) into the mastoid cavity. A detailed technical description of the valve implant is presented as well as some technical aspects of the valve implant based on the surgical anatomy of the endolymphatic sac.

Ear, Inner↗
PubMed1978

Unidirectional inner ear valve implant for endolymphatic sac surgery in Meniere's disease.

In five patients with long-standing Meniere's disease, a unidirectional inner ear valve was implanted into the endolymphatic sac (ELS) to facilitate removal of excess endolymph in the hydropic state. These patients were all candidates for ablative surgery. They all had intractable vertigo and severe hearing losses. Four out of five patients had positive preoperative glycerol tests. In the patients with positive glycerol tests, the group averages before surgery were as follows: pure-tone average (PTA), 63 dB; speech reception threshold (SRT), 79 dB; and discrimination score, 27%. All of the patients, except a patient with a negative glycerol test, benefited from the surgery, including exceptional hearing improvements, averages of 21 dB in PTA, 30.5 dB in SRT, and 48% in discrimination, which remained so for at least a one-year minimum follow-up. All patients with preoperative positive glycerol tests had a class A result according to the criteria set forth by the American Academy of Ophthalmology and Otolaryngology. The cumulative follow-up exceeded the minimal requirements by a factor of 39 times. The only failure was in a patient with a negative glycerol test, which was predictable. Results of tomography confirmed the correct position of the valve without evidence of migration or extrusion even in the failure. This new valve appears to be a safe and more effective implant than Silastic sheeting alone or any other ELS implant in patients with a positive glycerol test.

Adult↗
PubMed1976

Valve implants in filtering surgery.

A valve implant for glaucoma incorporated upper and lower intraocular pressure limits for outflow. The device consisted of an open Supramid tube sealed to a Silastic tube with a slit valve. The valve implants had opening pressures of 11 to 16 mm Hg and closing pressures 1 to 3 mm Hg lower. A surgical technique was developed in monkey eyes and applied later in modified form to three patients with glaucoma. In four of seven monkey eyes the implants remained in place and were patent for over one year. Follow-up studies were carried out for over six months in the three patients. In two patients the valve implants were functioning with controlled intraocular pressures. In one patient the implant migrated posteriorly. This was replaced by using a new valve and a buried fixation suture and has since functioned without problem. The valve implants were well tolerated and offered possibilities for predictable intraocular pressures after glaucoma surgery.

Adolescent↗