Does obesity affect the results of lumbar decompressive spinal surgery in the elderly?

The prevalence of obesity among the population is increasing, including in many elderly people. The purpose of this study was to evaluate whether lumbar spinal surgery in elderly patients with different body mass indices influences pain, satisfaction rate, and activities of daily living. Two hundred ninety-eight elderly patients (older than 65 years), 153 women and 145 men, who had decompressive laminectomy, discectomy, or combinations of these procedures during 1990 to 2000 were followed up. Indications for surgery included limitation in doing activities of daily living, severe pain, or both. The patients were classified into one of four categories in terms of their body mass index. The operative parameters, pain reduction, satisfaction rate, and activities of daily living using the Barthel index were assessed. The more obese patients were younger, tended to be female, and were more symptomatic. All four groups of patients had reduction in pain, improvement in activities of daily living, and were satisfied with the operation. Our data suggest that it is reasonable to operate on patients who are elderly and obese and who have lumbar symptoms, with the appropriate indications.     

Outcomes in patients admitted for rehabilitation with spinal neurological lesions following intervertebral disc herniation

BACKGROUND: Little information is available about the survival, neurological recovery, and length of stay in hospital for rehabilitation (LOS) of patients with spinal neurological deficit following disc herniation (DH). STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To report on outcomes and factors affecting these. SETTING: The Spinal Research Laboratory, Loewenstein Rehabilitation Hospital, Israel. SUBJECTS: A total of 158 patients with DH spinal neurological lesions (DHSNL). METHOD: Data were collected retrospectively. Survival was assessed using the Kaplan-Meier method; relative mortality risk by the Cox proportional hazard model. Neurological recovery was evaluated by calculating the change in Frankel grades, and factors that affect it were assessed by logistic regression. LOS associations were analyzed with ANOVA. RESULTS: The median age at lesion onset was 48 years, and the median survival 29 years. Age and gender had a significant effect on survival, but not so lesion severity, level, or decade of onset. Of the 69 patients who had Frankel grades A, B, or C on admission, 72% achieved useful recovery to grades D or E. The severity and level of the spinal neurological lesion (SNL) had a significant effect on recovery. The mean LOS was 87 days; it was significantly affected by lesion severity and level and by the decade of admission to rehabilitation, and decreased with time. CONCLUSIONS: Patients with DHSNL who were admitted for rehabilitation have favorable survival and recovery rates compared with previously studied patients with other types of SNL. Their LOS is probably a function of medical requirements, but is decreasing with time.     

Pharmacokinetics of the antimalarial drug, AQ-13, in rats and cynomolgus macaques

The purpose of this study was to evaluate the bioavailability and pharmacokinetics of a new antimalarial drug, AQ-13, a structural analog of chloroquine (CQ) that is active against CQ-resistant Plasmodium species, in rats and cynomolgus macaques. Sprague-Dawley rats (n = 4/sex) were administered a single dose of AQ-13 intravenously (i.v.) (10 mg/kg) or orally (20 or 102 mg/kg). Blood and plasma samples were collected at several timepoints. AQ-13 achieved C(max) after oral administration at approximately 3 to 4 h and could be detected in blood for 2 to 5 days after oral administration. The ratio of area under the curve (AUC) values at the high and low dose for AQ-13 deviated from an expected ratio of 5.0, indicating nonlinear kinetics. A metabolite peak was noted in the chromatograms that was identified as monodesethyl AQ-13. Oral bioavailability of AQ-13 was good, approximately 70%. The pharmacokinetics of AQ-13 was also determined in cynomolgus macaques after single (i.v., 10 mg/kg; oral, 20 or 100 mg/kg) and multiple doses (oral loading dose of 50, 100, or 200 mg/kg on first day followed by oral maintenance dose of 25, 50, or 100 mg/kg, respectively, for 6 days). The AUC and C(max) values following single oral dose administration were not dose proportional; the C(max) value for AQ-13 was 15-fold higher following an oral dose of 100 mg/kg compared to 20 mg/kg. Monodesethyl AQ-13 was a significant metabolite formed by cynomolgus macaques and the corresponding C(max) values for this metabolite increased only 3.8-fold over the dose range, suggesting that the formation of monodesethyl AQ-13 is saturable in this species. The bioavailability of AQ-13 in cynomolgus macaques following oral administration was 23.8% for the 20-mg/kg group and 47.6% for the 100-mg/kg group. Following repeat dose administration, high concentrations of monodesethyl AQ-13 were observed in the blood by day 4, exceeding the AQ-13 blood concentrations through day 22. Saturation of metabolic pathways and reduced metabolite elimination after higher doses are suggested to play a key role in AQ-13 pharmacokinetics in macaques. In summary, the pharmacokinetic profile and metabolism of AQ-13 are very similar to that reported in the literature for chloroquine, suggesting that this new agent is a promising candidate for further development for the treatment of chloroquine-resistant malaria.     

Tc-99m HMPAO to demonstrate diffuse cortical necrosis in vivo

Tc-99m hexamethylpropylene amineoxime (HMPAO) is a novel radiopharmaceutical demonstrated to be a sensitive indicator of abnormalities of cerebral perfusion. Most reports in the literature have evaluated patients with gross perfusion deficits, such as cerebrovascular accidents, and with dementia, where patterns of diffuse perfusion deficit were reported comparable with those seen in PET studies. We report a patient in whom there was the rapid onset of dementia, with the HMPAO images demonstrating diffuse loss of cortical perfusion in a nonfocal, and nonsegmental, fashion. Correlation with postmortem examination demonstrates good concordance between the diffuse nature of HMPAO loss, and diffuse cortical necrosis throughout both cerebral hemispheres. The technique was shown to be more sensitive than transmission CT scanning in demonstrating the extent of the deficit, and it correlated closely with the functional deficits noted in the patient.     

Carbamazepine toxicity following Oxybutynin and Dantrolene administration: a case report

OBJECTIVE: To report a case of Carbamazepine toxicity following the administration of Oxybutynin and Dantrolene. STUDY DESIGN: A case report. SETTING: The Spinal Rehabilitation Department, Loewenstein Hospital, Raanana, Israel. METHODS: A patient with C6D tetraplegia who sustained intoxication because of drug interaction is presented. She had been treated by Carbamazepine 1000 mg/day for neuropathic pain for 2 years without clinical or laboratory signs of toxicity. After administration of Oxybutynin concomitantly with an increase in the dose of Dantrolene, she presented the clinical symptoms and laboratory finding of Carbamazepine intoxication. Trying to adjust the treatment to the patient's requirements, Carbamazepine together with Oxybutynin and Dantrolene was readministrated in lower doses. RESULTS: The combination of these drugs, even small doses, caused toxicity. Adding Dantrolene and Oxybutynin elevated the blood level of Carbamazepine, possibly by inhibition of cytochrome P450. CONCLUSION: A possible pharmacokinetic interaction between Dantrolene and Oxybutynin should be borne in mind when considering Carbamazepine medication for a patient with a spinal cord lesion.     

The role of radiofrequency in the treatment of mechanical pain of spinal origin

Radiofrequency (RF) ablation is a method that has been gaining popularity over the past few years among spinal surgeons. It has a role when dealing with pain of spinal origin, either mechanical or neuropathic, after conservative treatment has failed. In the present study, 122 patients with a minimal follow up of 1 year were examined at our institution after having undergone RF heat lesion of the medial branch for mechanical spinal pain (low back pain, thoracic pain or cervical pain). They were followed up 1, 3, 6 and 12 months after treatment. Twenty-two of them were additionally followed up at 18 months. After 1 month, 91 patients (75%) were satisfied with the results. After 3 months, 87 patients (71%) had significant pain relief, while in 35 patients (29%) there was no improvement. After 6 months of follow-up, 80 patients (66%) had pain relief and in 42 patients (34%) there was no effect. At 12-months follow-up, 77 patients (63%) showed good results and 45 patients (37%) had no effect. In the case of the 22 patients who were followed for 18 months, all showed significant pain relief. Minor complications occurred in 27 patients (22%), who had transient discomfort and burning pain. We concluded that RF is a safe and partially effective procedure for mechanical back pain.     

Impact of medical and nonmedical factors on physician decision making for HIV/AIDS antiretroviral treatment

To examine influences of medical factors (e.g., viral load) and nonmedical factors (e.g., patient characteristics) on treatment decisions for highly active antiretroviral therapy (HAART), we sent a survey to a random sample of 995 infectious disease physicians who treat patients with HIV/AIDS in the United States in August, 1998. The response rate was 53%. Respondents were asked to report their current practices with respect to antiretroviral treatment and the extent to which each of three medical and 17 nonmedical factors would influence them for or against prescribing HAART to a hypothetical HIV-positive patient. Most reported initiating HAART with findings of low CD4+ cell counts and high viral loads, and weighing CD4+ cell counts, viral load, and opportunistic infection heavily in their decisions to prescribe HAART. Patients' prior history of poor adherence was weighed very much against initiating HAART. Patient homelessness, heavy alcohol use, injection drug use, and prior psychiatric hospitalization were cited by most physicians as weighing against HAART initiation. Thus, most physicians in this sample follow guidelines for the use of HAART, and nonmedical factors related to patients' life situations are weighed as heavily as disease severity in treatment decisions. As HIV increasingly becomes a disease associated with economic disadvantage and other social health problems, it will be essential to develop interventions and care support systems to enable patients experiencing these problems to benefit from HIV treatment advances.     

Synthetic peptide specificity of anti-myelin basic protein from multiple sclerosis cerebrospinal fluid

Human myelin basic protein (h-MBP) purified from central nervous system (CNS) myelin has a molecular mass of 18.5 kDa and 170 residues. Eighteen synthetic peptides ranging from 8 to 25 residues and covering the length of h-MBP were prepared by the Fmoc method. Antibodies to h-MBP (anti-MBP) were isolated and purified from cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) by two-step affinity chromatography. Purified anti-MBP was reacted with increasing amounts of h-MBP as well as each of the 18 synthetic peptides in an initial liquid phase assay, and then titers of free anti-MBP in the resulting mixtures were determined by a solid phase radioimmunoassay. Purified anti-MBP was neutralized by h-MBP and 6 of the 18 synthetic peptides used in this study. The antibody was completely neutralized by peptides No. 12 (residues: 80-97), No. 15 (residues: 91-106) and No. 56 (residues: 75-95) and was partially neutralized by peptides No. 27 (residues: 61-75), No. 16 (residues: 64-78) and No. 21 (residues: 69-83). The 12 remaining synthetic peptides covering both the amino (residues 1-63) and carboxyl (residues 117-162) terminals of h-MBP did not neutralize purified anti-MBP. These results suggest that anti-MBP purified from CSF of patients with MS have affinity for discontinuous epitopes located between residues 61 and 106 on the h-MBP molecule. Alternatively anti-MBP may be polyspecific recognizing different amino acid sequences.