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Biomedical subjects

S Pomeranz

Publications and source records attributed to S Pomeranz.

At least 19 recordsLinked to original sources
PubMed1998

Moderate hypothermia for 48 hours after temporary epidural brain compression injury in a canine outcome model.

In a previous study with this dog model, post-insult hypothermia of 31 degrees C for 5 h prevented secondary intraventricular pressure (IVP) rise, but during 35 degrees C or 38 degrees C, one-half of the dogs developed delayed IVP rise to brain death. We hypothesized that 31 degrees C extended to 48 h would prevent brain herniation. Using epidural balloon inflation, we increased contralateral IVP to 62 mm Hg for 90 min. Controlled ventilation was to 72 h and intensive care to 96 h. Group 1 dogs (n = 10) were normothermic controls (37.5 degrees C). Group 2 dogs (n = 10) were surface-cooled from 15 to 45 min of balloon inflation and maintained at moderate hypothermia (31 degrees C) to 48 h. Rewarming was from 48 to 72 h. Four additional dogs of hypothermia Group 2 had to be excluded from analysis for pneumonia and/or bleeding diathesis. After balloon deflation, IVP increased to 20 mm Hg or greater at 154 +/- 215 (range 15-720) min following the insult in Group 1 and at 1394 +/- 1191 (range 210-3420) min in Group 2 (p = 0.004), still during 31 degrees C but without further increase during hypothermia. Further IVP rise led to brain death in Group 1 in 6 of 10 dogs at 44 +/- 18 (range 21-72) h (all during controlled ventilation); and in Group 2, in 6 of 10 dogs at 87 +/- 11 (range 72-96) h (p = 0.001), all after rewarming, during spontaneous breathing. Survival to 96 h was achieved by 4 of 10 dogs in Group 1, and by 7 of 10 dogs in Group 2 (NS). Three of the six brain deaths in Group 2 occurred at 96 h. The macroscopically damaged brain volume was only numerically smaller in Group 2. The vermis downward shift was 6.8 +/- 3.5 mm in Group 1, versus 4.7 +/- 2.2 mm in Group 2 (p = 0.05). In an adjunctive study, in 4 additional normothermic dogs, hemispheric cerebral blood flow showed post-insult hypoperfusion bilaterally but no evidence of hyperemia preceding IVP rise to brain death. In conclusion, in this model, moderate hypothermia during and for 48 h after temporary epidural brain compression can maintain a low IVP during hypothermia but cannot prevent lethal brain swelling after rewarming and may cause coagulopathy and pulmonary complications.

Animals↗
PubMed1997

Serotype-related differences in inflammatory response to Streptococcus pneumoniae in experimental meningitis.

It has been suggested that serotype influences severity of experimental pneumococcal meningitis. This hypothesis was tested with strains of serotypes 1, 5, 6B, 7F, 14, and 23F, prevalent in Israel, in an experimental rabbit model. Cerebrospinal fluid (CSF) bacterial titers, leukocyte densities, concentrations of lactate, protein, and glucose, tumor necrosis factor-alpha levels, brain water content, and cerebral blood flow were measured 18 h after inoculation of pneumococci. Serotypes 5 and 7F exhibited mild inflammatory responses (leukocytosis <1000/mm3, lactate <4 mmol/L); types 6B, 14, and 23F showed severe inflammatory responses (leukocytosis >5000/mm3, lactate >10 mmol/L); serotype 1 had intermediate inflammatory responses but exceptionally high CSF bacterial titers. Leukocyte count correlated with all other variables; lactate with all except brain water content. On the basis of 6 Streptococcus pneumoniae serotypes, three discrete levels of inflammatory responses could be delineated in experimental pneumococcal meningitis.

Animals↗
PubMed1997

Foraminal herniation of a lumbar disc mimicking neurinoma on CT and MR imaging.

A case of a large L3-L4 intervertebral disc herniation causing a widening of the intervertebral foramen is reported. There was a soft-tissue mas within the spinal canal and intervertebral foramen. The soft-tissue mass within the spinal canal and intervertebral foramen showed marked enhancement on magnetic resonance scans after injection of a paramagnetic contrast agent (Gd-DTPA). The combination of lesion configuration and paramagnetic contrast enhancement mimicked a spinal neurinoma. There exists a degree of overlap between the imaging of herniated discs and spinal neurinomas. When this overlap involves several aspects, such as anatomic configuration, mass enhancement, and secondary foraminal dilatation, the differential diagnosis between a herniated disc and a neurinoma may be problematic.

Diagnosis, Differential↗
PubMed1996

[Cranial base surgery].

A review of 172 consecutive patients who underwent surgery for cranial base tumors was undertaken to determine efficacy and complication rate. 95% of the tumors were benign or of low grade malignancy; 24% were greater than 4.5 cm in diameter and 34% were 3-4.5 cm; 32 were petro/clival and 17 cavernous sinus tumors. Radical tumor resection was attained in 60% and subtotal (> 90% of volume) in 35%. The mean preoperative Karnofsky functional score was 72, which postoperatively had improved significantly to 83.5 patients (2.9%) died perioperatively, and later an additional 3 died of their disease; 3/5 died following reoperation at other hospitals. 3 (1.7%) had major, prolonged deterioration following surgery. This series presents experience with, and demonstrates overall high quality outcome, in patients with cranial base tumors at a center with special interest in and facilities for cranial base surgery.

Female↗
PubMed1996

Subclinical status epilepticus in a child after closed head injury.

A 14-year-old girl with closed head injury and a normal computerized tomographic scan underwent an electroencephalographic tracing that surprisingly revealed typical status epilepticus electrical activity. No episodes of motor clinical convulsions were observed from the moment of trauma throughout the admission period. Treatment with phenytoin caused a dramatic clinical improvement. Repeated electroencephalogram (EEG) 4 days later was within normal limits. Posttraumatic seizures are reported after head injury, yet, the issue of "invisible" or "subclinical" seizures associated with trauma is not discussed. In these cases EEG, (an uncommon examination in the early period after head injury) may be the only tool for proper diagnosis and treatment with anticonvulsants. This case report raises the question of the role of EEG in the unconscious patients who does not present with obvious convulsions. Clinical indications for performing EEG after head trauma without seizures are discussed.

Adolescent↗
PubMed1995

Intracranial craniopharyngioma seeding following radical resection.

A rare case of intracranial seeding from a craniopharyngioma is presented. A 12-year-old boy underwent radical resection of a suprasellar craniopharyngioma 2 years previously. There had been no evidence of recurrence during follow-up. He became symptomatic 1 week prior to admission, when imaging showed a recurrent tumor. The metastatic, subfrontal craniopharyngioma was not anatomically connected to the suprasellar region, but originated from the floor of the anterior fossa along the former surgical approach. The significance of this finding and its relation to recurrent craniopharyngioma is discussed.

Child↗
PubMed1994

Intracranial haematomas following bone marrow transplantation.

Intracranial haemorrhage (ICH) is a known grave complication of leukaemia and has been described post mortem following bone marrow transplantation (BMT). Ante mortem following BMT, the incidence and significance of ICH is not well defined. The records of 471 bone marrow transplantation recipients over 11 years at the Hadassah University Hospital Bone Marrow Transplantation Department were reviewed. The relevant data of all patients with ICH were analysed. A resolute diagnostic and treatment protocol for subdural haematomas had been employed. The indication for transplantation in 273 of the patients was leukaemia. Thirteen of these patients developed subdural haematomas within 42 days of the transplant, and nine of these haematomas were bilateral. None of the 198 patients with other malignancies or nonmalignant indications for BMT (predominantly aplastic anaemia and beta thalassaemia major) had subdural haematomas. One thalassaemia patient and three leukaemia patients had intracerebral haematomas. There was no mortality or major morbidity from the subdural haematomas, which were all successfully resolved. In contrast, all of the patients with intracerebral haematomas consequently died. Subdural haematomas occur in approximately 5% of patients with leukaemia following BMT, but the clinical outcome is relatively benign. Intracerebral haematomas are a sporadic, lethal complication following BMT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Giant cranial base tumours.

Thirty-three patients with giant (diameter > or = 4.5 cm) cranial base tumours who underwent surgery at the Hadassah Hospital over the last ten years are described. Twenty-three of the patients had meningiomas, 4 neurinomas, one giant cell tumour, one haemangiopericytoma, and 4 had malignant meningiomas. Four tumours were at the cerebellopontine angle, 9 within the anterior cranial fossa, 8 petroclival, 8 on middle fossa floor, and 4 along the sphenoid ridge. The average pre-operative symptom duration was 31 months, range 3-180 months. Nineteen patients had a radical tumour resection, 10 subtotal, and 4 a partial resection on an average 1.7 operations per patient. The mean follow-up period from the first operation was 39 months (range 2-120). There was no mortality peri-operatively or during the follow-up period. The mean pre-operative Karnofsky score was 68 and at the last follow-up 76. There was no correlation between histology and degree of resection, complications, or status at last follow-up. The best resections (92% radical) and outcome (mean Karnofsky 92) with the least number of operations (mean 1.4) were in the anterior fossa and along the sphenoid wing. The patients requiring the most operations (mean 2.1), having the smallest percentage of radical resections (25%) and the least favourable outcomes (mean Karnofsky 52) were those with petroclival tumours. Patients with giant cranial base tumours have a good overall long-term prognosis, but especially those with petroclival tumours challenge us to improve our techniques.

Adolescent↗
PubMed1994

Conservative treatment of a traumatic subdural hematoma of the posterior fossa in a child: case report.

Traumatic posterior fossa hematomas are uncommon. Subdural hematomas in this location are probably the rarest. The natural history in acute cases is one of rapid deterioration and death from brain-stem compression. Rapid surgical intervention is indicated in acute cases. We report a case of a traumatic posterior fossa subdural hematoma in a 3-year-old child treated conservatively with a good outcome.

Child, Preschool↗
PubMed1994

Sciatic nerve palsy as a complication after acoustic neurinoma resection in the sitting position.

We present a case of sciatic neuropathy after operation in the sitting position. Sciatic nerve palsy as a complication of the sitting position appears to be extremely rare. The patient we describe was a short, plump woman. To attain optimal surgical exposure, a greater flexion of the hips than usual was utilized. That may explain the possible stretch injury of the sciatic nerve.

Adolescent↗
PubMed1994

Nystagmus as the presentation of tentorial incisure subdural haematoma.

A case of chronic subdural haematoma in the posterior fossa, secondary to anticoagulant treatment, is presented. The unusual clinical presentation of vertigo and nystagmus and the atypical CT are discussed. This seems to be the first report to describe a chronic subdural haematoma in the posterior fossa in an alive adult.

Aged↗
PubMed1994

Excision of petroclival tumors by a total petrosectomy approach.

The surgical removal of intradural petroclival tumors of any size is demanding because of the restricted surgical exposure and relation of the tumor with the brain stem, cranial nerves, and vertebrobasilar artery and branches. When petroclival tumors are large or giant sized and involve multiple areas of the clivus, adequate surgical exposure is difficult to achieve, yet is critical for safe tumor removal. In 17 patients with extensive petroclival tumors, total removal of the petrous bone was performed to gain a wide and shallow surgical exposure. This report details the intraoperative and postoperative complications, cranial nerve status, pre- and postoperative disability scores, and extent of tumor resection in these 17 patients. Deterioration of facial nerve function was the most common new cranial nerve injury following surgery. Three patients suffered major neurologic complications; six other patients suffered significant but temporary neurologic complications. Gross total tumor resection was accomplished in 9 of 17 patients, and most patients (15/17) maintained or improved their disability status. Tumor residual was related to cavernous sinus involvement, vascular encasement, or brainstem pial invasion. Total petrosectomy is an intensive and complex approach with inherent morbidity and thus should be reserved for extensive petroclival tumors that cannot be removed using less complicated approaches.

Adolescent↗
PubMed1993

The effect of intracranial hypotension on cerebral blood flow in a feline model.

Intracranial hypotension is a known clinical entity but its pathophysiology has been meagerly studied. Any setting with cerebrospinal fluid leakage or drainage can cause intracranial hypotension. A feline model of kaolin induced chronic hydrocephalus with controlled cerebrospinal fluid drainage from a lateral ventricle yields reproducible intracranial hypotension of up to -15 torr for several hours to -80 torr of about 10 minutes. The magnitude of this hypotension is significantly greater than can be attained by cisterna magna drainage. This new model allows multiple cerebral parameters to be studied during intracranial hypotension. In 11 cats with stable blood pressure and intracranial hypotension of at least -15 torr, regional blood flow utilizing the hydrogen clearance method in the cerebral cortex and subcortical nuclei was unchanged relative to the baseline. These results imply that: 1) cerebral vascular autoregulation is maintained during significantly increased perfusion pressure due to negative intracranial pressure, 2) the symptomatology of clinical intracranial hypotension is not due to decreased cerebral perfusion.

Animals↗
PubMed1993

The effect of resuscitative moderate hypothermia following epidural brain compression on cerebral damage in a canine outcome model.

A canine model of temporary epidural cerebral compression and standardized intensive care was developed to evaluate the effect of resuscitative (postinsult) moderate systemic hypothermia. A balloon was inflated over the temporal region to maintain contralateral intraventricular pressure (IVP) at 62 mm Hg for 90 minutes. For a 66-hour period after initiation of brain compression, the intubated dogs received controlled ventilation and standard intensive care. From 66 to 90 hours postinjury, the extubated dogs were evaluated as to functional outcome. Morphological brain damage was evaluated at 90 hours or earlier if brain death occurred. Eight dogs in a control group were maintained at a body of temperature of 38 degrees C. Eight treated dogs had core body temperature reduced by surface cooling starting 15 minutes after balloon inflation, first to 31 degrees C for 5 hours and then to 35 degrees C from 5 to 62 hours after insult. Intraventricular pressure increased to 20 mm Hg or greater in the control group at a mean of 2.9 hours (range 2 to 4 hours) following the insult, and in the hypothermic group at a mean of 14.8 hours (range 5 to 30 hours)--that is, during the time period when the body temperature was 35 degrees C, not 31 degrees C (p = 0.01). There was no difference in peak pressures between the two groups. Brain death occurred in four of the eight dogs in the normothermic group at 18, 24, 24, and 48 hours (mean +/- standard deviation 28 +/- 13 hours) and in three of the eight in the hypothermic group at 27, 42, and 45 hours (mean 38 +/- 10 hours) (not significant). The animals surviving 90 hours (four in the normothermic and five in the hypothermic group) were neurologically near normal. The total mean macroscopically damaged brain volume was 2584 +/- 1890 cu mm in the normothermic versus 765 +/- 611 cu mm in the hypothermic group (p = 0.03). The mean necrotic volume was 741 +/- 599 cu mm in the normothermic versus 263 +/- 346 cu mm in the hypothermic group (p = 0.07). Microscopically, the damaged regions consisted of ischemic neurons, reactive glia, edema, vascular endothelial hypertrophy, and erythrocyte extravasation. It is concluded that, in this model, immediate postinsult hypothermia of 31 degrees C (not 35 degrees C) for 5 hours prevents a rise in IVP and significantly decreases cerebral tissue damage, but does not prevent brain herniation during rewarming.

Animals↗
PubMed1992

Temporal bone neoplasms: a report on 20 surgically treated cases.

The surgical resection of neoplasms involving the petrous bone and surrounding areas in 20 patients is reported. Technical advances described include the total resection of several tumors previously considered inoperable due to involvement of dura and brain, petrous internal carotid artery (ICA), the vein of Labbé, and adjacent areas such as the clivus and the cavernous sinus. Areas of reconstruction after resection included the ICA, the seventh and 11th cranial nerves, and the cranial base, often requiring the use of vascularized flaps. There were no intraoperative deaths. Many patients experienced significant temporary morbidity related primarily to wound healing and to lower cranial nerve palsy; however, all but three patients (all with fast-growing malignancies) returned to their preoperative functional status. During a median follow-up period of 30 months (range 17 to 63 months), the 10 patients with benign tumors and slow-growing malignancies fared well, seven being alive and disease-free. The 10 patients with fast-growing malignancies fared poorly, only two being alive without disease. This outcome appeared to be related to tumor pathology and extent of invasion; both survivors harbored tumors confined to the petrous bone. An anatomical classification system of tumor spread is introduced, which should be considered concomitantly with tumor pathology.

Adolescent↗