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Biomedical subjects

A A Patil

Publications and source records attributed to A A Patil.

At least 19 recordsLinked to original sources
PubMed1995

Modifications of transnasal and transoral stereotactic procedures--technical notes.

Stereotactic transnasal and transoral procedures have been reported by different authors in the past. In this paper, several modifications of these methods are described. The modifications are: transnasal approach to the frontal skull base and suprasellar regions; and transoral approaches to the clivus, the petroclival junction, medial part of the cerebellopontine angle and the lateral mass of C-1. Eleven patients were operated on using these modifications. The procedures were for biopsy and brachytherapy. No complications resulted from the procedures.

Adolescent↗
PubMed1995

Stereotactic location and excision of seizure focus with xenon-enhanced CT.

A case of intractable seizures, originating in the motor cortex, was successfully treated with excision of the seizure focus after precise location of the focus on depth electrode recordings. The depth electrode was placed stereotactically with coordinates from xenon-enhanced CT images. Prior attempts at treating the seizures with ablation of seizure foci had resulted in disappearance of seizure activity on electrocorticography study without cessation of clinical seizures.

Brain Mapping↗
PubMed1994

Electroconvergent cautery.

A new cautery system known as the electroconvergent cautery system is described. This cautery system uses a radiofrequency current of 13.56 MHz. The current is passed through an amplifier, an impedance matching system, and a loading and tuning coil into a probe. After the probe tip is touched to the tissue, the mismatch of impedance between the probe tip and the generator is minimized to almost zero, resulting in high-current density at the probe tip, which causes pinpoint heating of the tissue at the point where it is touched by the probe without spread of heat to the surrounding tissue. This heat can cut and vaporize tissue and coagulate vessels. The probe can also be used to coagulate vessels with standard surgical forceps. Because convergence of energy is used for tissue heating, a grounding pad is not needed. The system can also be used under cerebrospinal fluid or saline.

Astrocytoma↗
PubMed1992

Stereotactic external beam irradiation system.

Stereotactic localization is of vital importance in treating small intracranial lesions either with interstitial or external beam irradiation. This article describes a simple, fast, accurate, and verifiable system that can be used with a standard computerized axial tomography (CAT) scanner and linear accelerator for stereotactic external beam irradiation.

Brachytherapy↗
PubMed1991

Free-standing, stereotactic, microsurgical retraction technique in "key hole" intracranial procedures.

Free-standing, stereotactic, microsurgical retraction technique involves integration of a standard image-guided stereotaxis, an operating microscope and free-standing micro-retractors, data acquisition from computed tomography (CT) images, trajectory determination, and obtaining tumor configuration "in line" with the trajectory using standard CT computer program. The free-standing stereotactic micro-retractors are directed to the lesion using the stereotactic frame. The remainder of the procedure is carried out independent of the stereotactic frame. The technique allows unobstructed access to deep lesions through a "key-hole" opening with excellent visualization of the lesions, and accurate retractor placement. Independent retractor movement also allows visualization of the different corners of the wound. Experience with the first 15 consecutive procedures for stereotactic excision of deep lesions using the Patil frame is reported. Based on this preliminary experience, this technique is free of obstruction, accurate and safe.

Adolescent↗
PubMed1991

Axial herniation with brain stem deformity as a cause of sleep apnea.

A patient with an intracerebral hematoma and associated edema in the high right hemisphere parasagittal convexity had several episodes of apnea at night and during the day when she was asleep. On computed tomography (CT) scan, the hematoma demonstrated no evidence of brainstem compression. Sagittal magnetic resonance image (MRI), revealed the hematoma and edema mass resulted in central herniation with axial deformity of the brainstem. This is believed to be the cause of the apneic episodes. Treatment with mannitol and steroids promptly relieved the symptom.

Brain Edema↗
PubMed1991

Accuracy of thalamotomy target determination using axial images only.

The target point for thalamotomy is generally determined in relationship to the intercommissural line. Standard axial computed tomography (CT) images can show both the anterior and posterior commissures. However, these commissures may not always be visible on the same axial image, as the plane in which the two commissures are located may not be the same as the plane of scanning. Mathematical calculations were performed to determine the degree of error that would occur if the target point determination was performed using axial images alone, even when the two commissures were not in the same plane as the CT images. The degree of error was found to be directly proportional to the distance between the plane of scanning for the two commissures. For each millimeter separation of these planes an error of approximately 0.11 mm in the z-coordinate (caudo-cephaled distance) and 0.04 mm in the y-coordinate (antero-posterior distance) was observed. These errors were felt to be negligible, especially since the final target point determination is based on physiological responses.

Humans↗
PubMed1991

Intraoperative calibration of the Patil stereotactic system during computed tomography (CT) guided stereotactic procedures--a technical note.

A method for intraoperative calibration of the Patil stereotactic system is described. After adjusting the z and y coordinates, a marker is placed in the pivot block and a CT scan is obtained. The presence of the marker in the indicator block on the same horizontal line as the target, on the image of the target, would indicate that the y and z coordinates adjustments are accurate. After the arc is attached with the x coordinate adjusted, a CT scan is obtained with the arc vertical and the probe holder at zero angle (from the vertical) position. The presence of the middle of the probe holder in the same vertical line as the target would indicate accurate x coordinate adjustment. This technique, which can be applied also to other stereotactic systems, allows the surgeon to check not only the accuracy of the system but also the accuracy of the procedure prior to inserting the probe into the brain.

Brain↗
PubMed1991

Brachytherapy: a viable alternative in the management of basal meningiomas.

Thirteen patients with intracranial meningiomas of the skull base were treated with one or more high-activity iodine-125 seeds. In 11 patients, the seeds were implanted stereotactically under local anesthesia. A minimum dose of 100 to 500 Gy was delivered to the tumor at a dose rate of 5 to 25 cGy/h. Indications for this procedure included recurrence after initial surgery or as the primary modality of treatment in patients who were not candidates for surgery. All 13 patients are alive at a median follow-up of 15 months. Nine of 11 patients (82%) without calcification in their meningiomas achieved complete response. The remaining 4 patients-2 with calcification and 2 without--achieved partial response. No early or late complications were observed. We conclude from our experience that both recurrent and primary meningiomas of the skull base can be treated effectively with permanent iodine-125 brachytherapy.

Adult↗
PubMed1990

Intraventricular neurocytoma: a report of two cases.

Intraventricular neurocytoma is a rare clinicopathological entity that has been recently recognized. Previous reports have not described the magnetic resonance imaging findings of this tumor. This paper describes two patients with neurocytoma in which serpiginous flow voids and isointensity with cortex were distinctive features on the magnetic resonance imaging scan. Immunohistochemical studies showed reactivity for neuron-specific enolase, Leu-7, and S-100 protein.

Adult↗
PubMed1989

Survival of patients with glioblastoma multiforme treated by intraoperative high-activity cobalt 60 endocurietherapy.

The authors report their initial treatment results in 49 patients with glioblastoma multiforme (GM) who received intraoperative endocurietherapy (ECT) with high-activity cobalt 60 (60Co) probe. Thirty poor prognosis (unresectable tumor) patients (Group I) with newly diagnosed GM were treated by either biopsy or subtotal excision, followed by 20.00-Gy single-fraction 60Co probe ECT, and 60.00-Gy external-beam radiation therapy (EXRT) (80.00 Gy total tumor dose). Nineteen patients (Group II) with recurrent, previously resected and externally irradiated GM were retreated with 20.00-Gy single-fraction 60Co probe ECT alone. The authors' initial experience with intraoperative ECT of GM is discussed.

Adolescent↗
PubMed1989

Transoral stereotactic biopsy of the second cervical vertebral body: case report with technical note.

Although the transoral approach to the atlantoaxial region is generally an open surgical procedure, in patients in whom only tissue diagnosis is required, a needle biopsy can be done. In this paper a patient with a metastatic lesion in the second cervical vertebral body is presented, and the technique for needle biopsy of the second cervical body using stereotactic methods is described.

Adenocarcinoma↗
PubMed1988

Preliminary studies on combiners and combinations for quality traits in tomato (Lycopersicon esculentum Mill.).

Line x Tester analysis of 2 testers and 10 lines was conducted for fruit quality characters. Though both general (gca) and specific combining ability (sca) variances contributed significantly for these traits, the contribution of sca variance was more prominent for titratable acidity, total soluble solids and ascorbic acid content, while for pericarp thickness gca variance was more important. The highest gca effects for pericarp thickness, total soluble solids, ascorbic acid content and titratable acidity were recorded by the lines SM, Sioux, TT and SW 72, respectively. Based on pooled gca score, SW 72 was recognised as a good combiner for quality traits. The magnitude and significance of sca effects varied with the characters. Two superior crosses were identified and the implication of combining ability effects on handling these crosses are discussed.

Analysis of Variance↗
PubMed1988

Properties of electromagnetic field focusing probe.

The electromagnetic field focusing (EFF) apparatus consists of a radio frequency generator, solenoidal coil, and a hand-held or catheter probe. Applications such as aneurysm treatment, angioplasty, and neurosurgery in various models have been reported. The probe is operated in the near field (within one wavelength of an electromagnetic field source) of a coil inducing eddy currents in biological tissues, producing maximal convergence of the induced current at the probe tip. The probe produces very high temperatures depending on the wattage selected for the given radio frequency of output power. The high temperature can be used in cutting, cauterizing, or vaporizing. The EFF probe is comparable to different types of lasers and to bipolar and monopolar cautery. The EFF probe can be used with catheters or endoscopes. Objectives of this study were to determine what the thermal properties of the EFF probe are and how instrument parameters can be varied to obtain different temperatures in the tissue near the probe tip. In this study an F2 catheter was used as an insulated sheath and the tip of the guide wire was used as the probe tip. Different powers, wave forms, coil-to-probe distances, and probe-tip lengths were tested on a phantom that simulates tissue electrical properties. Some of the experiments were conducted under normal saline to simulate treatment of tissue with body fluids such as blood vessels or brain tissue under normal physiologic conditions. It is concluded that the EFF probe has the advantages of easy manipulation, relative safety, cost effectiveness, and a high degree of spatial control.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocoagulation↗