Biomedical subjects
Publications and source records attributed to A Goel.
An alternative method of preservation of the skull bone flap in the subgaleal space is described. The method was used in eight patients and the flap was successfully replaced to the original site in four of these cases. The period of preservation varied from 3-16 months. The procedure had the advantages of ease of placement and prolonged survival of flap.
For a subtemporal transtentorial approach to the anterior part of the posterior fossa a tentorial dural flap is described. An incision is begun at the free edge of the tentorium at the level of the posterior edge of the cerebral peduncle and is then directed anterolaterally towards the superior petrosal sinus. A triangular flap of the tentorial dura is everted over the superior petrosal sinus. The flap has the advantage of being simple and safe, and provides a wide window to the infratentorial structures. In addition the occasional troublesome bleeding from the superior petrosal sinus and the petrosal vein is avoided. The fourth and fifth cranial nerves are protected and exposed widely.
A series of 22 cases of large suprasellar tumours was studied retrospectively. These patients had undergone a preoperative shunt to facilitate surgical exposure of the tumour and to reduce intracranial pressure in critically ill patients. Our observations on the clinical progress of these patients following the shunt is analysed. Nine patients worsened to a varying degree following insertion of the shunt. Seven patients became drowsy, one developed worsening of vision and a hemiparesis, and one became an akinetic mute. The worsening was probably related to alteration of intracranial pressure dynamics and resultant compression in the hypothalamic region by subtle superior migration of the tumour. Operative difficulties were encountered during the dissection of the tumour from the neural structures in these cases. We conclude that with the availability of modern decongestive measures and basal surgical exposures, preoperative shunting is rarely indicated and can be occasionally dangerous. In the absence of actual proof, it is postulated that the secondary ventricular enlargement appears to be a protective mechanism of the brain helping to reduce tumour pressure on the basal forebrain structures.
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A 32-year-old female presented with a rare thoracic intradural anterior epidermoid tumor manifesting as acute onset of paraplegia. The tumor was completely removed through a laminectomy. She achieved a full neurological recovery. This is a very unusual presentation for an epidermoid tumor.
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Two cases of giant pituitary tumours are reported. The patients underwent transcranial operation, one by the pterional and one by the subfrontal route. Only partial resection of the tumour was possible in each instance for various reasons. Acute worsening of the clinical condition in the immediate postoperative phase led to reoperation in both patients. In one case the reoperation was carried out within 45 min of the closure of the wound and in the other after 12 h. Massive swelling of the tumour with evidence of haemorrhagic infarction was a surprise finding. After a turbulent postoperative phase, both patients died. We postulate that these patients developed pituitary apoplexy of the residual tumours.
Five cases of Chiari malformation associated with atlantoaxial dislocation are presented. A lateral plate and screw fixation was performed in all cases. Reversal foramen magnotomy was performed in three cases and two patients underwent the conventional posterior bony decompression for Chiari malformation. In an average postoperative follow-up period of 8 months (range 3 months to 2 years) neurological symptoms and signs improved in all patients, with radiological and clinical evidence of bony union and stability of the craniovertebral region. The surgical problems encountered in such cases where a posterior decompression was required in addition to a fixation procedure are enumerated in this report. The advantages of the proposed operations are described.
A case of intracavernous sinus cavernous hemangioma is reported. The tumor was totally resected en masse. The management of the lesion and technical issues concerning the surgery are discussed.
Two case reports illustrate a long vascular pedicle cranial bone flap. A split or full thickness skull bone flap is based on the pericranium layer. The temporalis muscle with its overlying fascial layers and vascular pedicles form the base of this flap and assure its adequate vascularization. The technique and its uses in the reconstruction of calvarial defects is discussed.
The results from the experiments performed with a mutant deficient in citrate synthase activity can be summarized as follows. (1) Totally blocking entry into the TCA cycle did not appreciably alter the cellular ATP yield. The unchanged yield suggests that for growth on abundant glucose, the sensitivity of ATP yield to TCA cycle flux is low. ATP production in the mutant is altered, in part, by modulating the relative amounts of formate and acetate produced. (2) The in vivo operation of pyruvate-formate lyase and malic enzyme corresponds to proposals developed from in vitro studies. Namely, pyruvate activates the former, and acetyl CoA inhibits the latter. Overall, the diversion of pyruvate to formate under aerobic conditions constitutes an adaptation of the mutant to the enzymatic lesion. The low alpha-ketoglutarate dehydrogenase flux estimated for the mutant indicates that the enzyme is highly repressed in cells growing rapidly on glucose, which is in accord with prior induction-repression studies. Moreover, the lack of a change in uptake flux during the bulk of batch growth is consistent with prior induction-repression studies. (3) The mutant exhibits a heightened sensitivity to CO2 as compared to wild-type counterparts. Growth rate is increased, and the production of formate, malate, glycerate, and pyruvate is reduced. This sensitivity illustrates that citrate synthase is more than an expendable component in an amphibolic pathway. Its presence in wild-type cells "immunizes" against the effect of CO2 fluctuations. (4) The effects of CO2 can be tentatively explained by assuming that the PEP carboxylase-catalyzed reaction is stimulated.
A case is reported where a vascularized outer-table of the frontal bone was successfully used to reconstruct a large defect in the anterior skull base following excision of a massive olfactory groove meningioma extending into the ethmoid sinuses. The flap provided a firm barrier between the cranial cavity and paranasal air sinuses, as the dural and bony integrity of the base was compromised after the radical resection of the tumour. It appears that such a flap can be effectively used for skull base reconstruction.
Our experience with 30 cases of atlanto-axial dislocation, over the period of 3 years and 9 months, is described. A modified plate and screw method of fixation of the lateral masses of the atlas and axis was successfully used in these cases. The technical aspects and merits of the method, wherein a 100% union rate was achieved, with no morbidity, mortality, or instrument fatigue or failure, are presented. The average follow-up period is of 19 months. The technique provided immediate rigid segmental internal fixation, permitting early mobilization with minimal external support. Onlay and interfacetal bone grafts subsequently produced bony fusion. Direct application of screws to the atlas and axis, thus utilizing the firm purchase in their thick and large cortico-cancellous lateral mass, provides a biomechanically strong fixation of the region. Occipito-cervical fusion can be achieved in selected cases by a modification of the method. It appears that such a method of fixation could be useful at least in some complex congenital or traumatic craniovertebral region instability where the conventional methods have failed or are not suitable.
This study was undertaken to investigate the protective effect of Liv-52, a herbal formulation, on various serum and liver marker enzymes, lipid peroxidation and histological changes in the liver of male albino rats suffering long-term carbon tetrachloride (CCl4) poisoning. It was observed that the activities of serum marker enzymes, hepatic enzymes and NADPH-dependent lipid peroxidation were significantly elevated after treatment with CCl4. However, in rats given Liv-52 at the same time as CCl4, the levels of all the marker enzymes were closer to those found in control animals. A similar trend was seen in the case of lipid peroxidation after Liv-52 treatment. CCl4 alone caused severe liver damage, but when Liv-52 was simultaneously given, there was much less effect on the structure of the organ. Circulating T3 and T4 concentrations were also determined after 6 weeks of simultaneous treatment with Liv-52 and CCl4. Concentrations of T3 were significantly lowered after CCl4 treatment alone, but Liv-52 administration together with CCl4 resulted in maintenance of the T3 activity within normal limits, thus suggesting indirect beneficial effects of Liv-52 on the regulation of thyroid hormone concentrations.
We present a case of hypoparathyroidism, demonstrating extensive intracranial calcification, not only in basal ganglia, but also outside the extrapyramidal system. The patient presented with an unexplained epileptifors disorder, accompanied by extrapyramidal dysfunction in the form of choreoathetosis and hemiballismus. Hemiballismus is reported for the first time to our knowledge in association with hypoparathyroidism.
A case of massive benign osteoblastoma involving the clivus and atlas is reported. Usually, these tumours involve the posterior elements of a vertebra and are detected when small as a result of the usual presenting symptom of pain. The unusual site, massive size and presentation with neurological deficits are rare for benign osteoblastomas. The problems encountered in the surgical management of the patient are discussed.
A temporalis osteomyoplastic bone flap was successfully used for reconstruction of the middle cranial fossa base. Rotation vascularized pedicle bone flaps are particularly suited for reconstruction after skull base surgery.