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Biomedical subjects

Ricardo Vallejo

Publications and source records attributed to Ricardo Vallejo.

At least 19 recordsLinked to original sources
PubMed2006

Percutaneous cement injection into a created cavity for the treatment of vertebral body fracture: preliminary results of a new vertebroplasty technique.

OBJECTIVES: Vertebral body fractures (VBFs) are the most common complication of osteoporosis. Minimally invasive placement of cement to stabilize VBFs results in significant pain reduction and improved performance of daily activities. The authors describe a modified percutaneous vertebroplasty (PV) procedure during which a cavity is created manually in the VBF, allowing the cement to be injected with less resistance. METHODS: Data were gathered from a retrospective chart review from 15 consecutive patients with acute compression VBFs who underwent 33 PV procedures with the Cavity Creation System. Mean follow-up was 30 weeks. Oral opiate intake, quality of life improvement, and visual analog pain scores (VAS) were measured before and 1 month after the procedure. RESULTS: All 15 patients exhibited a reduction in pain VAS (mean reduction 5.9 +/- 2.5). Improvement in quality of life was demonstrated by lower (improved) FACIT scores in the General Activity, Enjoyment of Life, Mood, Normal Work Routine, and Sleep subscales. In addition, opioid use decreased in 10 of the 12 (83%) patients who were taking opioids before surgery. In eight (67%) patients, opioid use decreased by over 50%. Complications included extrusion of cement in two patients (an incidence of 5.7% of the levels operated) and two patients with intraoperative rib fractures. No postoperative neurologic deficits were noted. CONCLUSIONS: The Cavity Creation System is a safe, cost-effective treatment of VBF resulting in good/excellent pain relief and an improved quality of life.

Activities of Daily Living↗
PubMed2006

Vertebroplasty.

Explore the source record for details and available documents.

Bone Cements↗
PubMed2005

Low back pain.

Explore the source record for details and available documents.

Journal Article↗
PubMed2005

Anterior cervical approach for stellate ganglion and T2 to T3 sympathetic blocks: a novel technique.

BACKGROUND: Stellate ganglion block is used for the diagnosis and treatment of sympathetically maintained pain syndromes. Multiple anatomic variations and inaccurate sympathetic block may mislead the diagnosis and prevent patients from receiving potentially beneficial interventions. We describe a novel approach to blockade of the sympathetic chain at C7 and at T2 to T3 with a single-needle injection. TECHNIQUE: With the patient in supine position, the uncinate process of C7 is identified fluoroscopically as a target for insertion of a catheter through a Touhy needle. The catheter is directed caudally to the junction of T2 and T3. Contrast injection confirms the spread to the appropriate levels before injection of local anesthetic. CONCLUSION: This novel approach to blockade of the upper extremity sympathetic innervation may enhance diagnostic accuracy and therapeutic benefit as compared with traditional approaches to the stellate ganglion alone. This approach may be expected to decrease the risk of pneumothorax when compared with the posterior approach to T2 to T3.

Journal Article↗
PubMed2004

Respiratory distress after intrathecal baclofen withdrawal.

We present the case of a 19-yr-old woman with a history of generalized dystonia who developed sudden onset of adductor spasms of the vocal cords and increased dystonia after the interruption or intrathecal baclofen therapy. Her symptoms resolved after intrathecal baclofen was restored. In patients with dystonia receiving intrathecal baclofen therapy, the onset of dyspnea associated with increased muscle tone should prompt the investigation of baclofen withdrawal.

Adult↗
PubMed2004

Seizures after a Bier block with clonidine and lidocaine.

A 47-yr-old man with history of complex regional pain syndrome type 1 underwent an IV Bier block with a mixture of lidocaine and clonidine. The tourniquet was deflated after 60 min, and approximately 10 min later he presented with complex partial seizures. The possible mechanisms for this are discussed, and the effects of clonidine, lidocaine, and the mixture of both are reviewed, as are four additional published cases reporting seizures after the administration of clonidine.

Adrenergic alpha-Agonists↗
PubMed2003

The predictive value of sympathetic block for the success of spinal cord stimulation.

OBJECTIVE: The purpose of this study was to assess the predictive value of response to sympathetic blockade (SB) on the success rate of spinal cord stimulation (SCS) in patients with complex regional pain syndrome. METHODS: We performed a retrospective study on 23 patients with complex regional pain syndrome who underwent both SB and subsequent SCS trials in the past 3 years at the Massachusetts General Hospital Pain Center, Boston, MA, and Walter Reed Army Medical Center, Washington, DC. Fifteen of these patients underwent permanent placement of an SCS device, and pain relief at 1- and 9-month follow-up was recorded. RESULTS: Among the 23 patients included in the study, those having transient pain relief with SB were more likely to have a positive SCS trial: all 13 with positive SB had good pain relief during the trial, compared with only 3 of the 10 with negative SB (100% versus 30%, P < 0.001). Among the 10 patients with negative SB, 7 noted poor pain relief during the trial despite adequate coverage, and they did not undergo placement of a permanent device. Among the patients who underwent permanent placement of an SCS device, those who received good pain relief with SB were more likely to have greater than 50% pain relief at 1-month follow-up (100% versus 33%, P = 0.029) and 9-month follow-up (87.5% versus 33.3%, P = 0.15). CONCLUSION: We conclude that patients with good response to SB before SCS are more likely to have a positive response during their SCS trial and long-term pain relief after placement of permanent SCS device.

Adult↗
PubMed2003

Perioperative immunosuppression in cancer patients.

Cancer patients commonly undergo surgical procedures. The perioperative period is characterized by immunosuppression and may predispose already immunosupressed cancer patients to tumor spread. Cancer patients typically show depression of both cellular and humoral immune functions. Possible mediating factors for immunosuppression during the perioperative period include anesthetic agents, opioids, surgery, blood transfusions, temperature changes, pain, and psychological stress. A surgically mediated decrease in natural killer (NK) cell activity has been implicated as the major contributing factor associated with an increase in metastasis. The decreased NK cell activity during the perioperative period is associated with increased risk of mortality and cancer. Commonly used anesthetic agents and opioids are known to inhibit NK cell activity. Despite the in vivo evidence of anesthetic- and analgesic-agent-mediated immunosupression, surgery by itself results in a three- to four-fold increase in retention of metastasis when compared to the groups in which anesthesia and analgesia were combined. The negative consequences associated with perioperative immunosuppression may be decreased by several strategies, including aggressive pain control, selection of specific anesthetic and analgesic agents, avoidance of unnecessary transfusions, and delay of elective surgeries until the patient's nutritional and immune status is optimized. Recognizing and neutralizing its mediating factors, perioperative immunosuppression in cancer patients may be reduced.

Analgesics↗
PubMed2003

Human immunodeficiency virus type 1 pharmacogenomics in clinical practice: relevance of HIV-1 drug resistance testing (Part 1).

Throughout most of the past century, physicians could offer patients no treatments for infections caused by viruses. The experience with treatment of infection by human immunodeficiency virus (HIV) has changed the way healthcare workers deal with viral infections and has triggered a growing rate of discovery and use of antiviral agents, the first fruits of the expanding genomics revolution. HIV treatment also provides an informative paradigm for pharmacogenomics because control of infection and its consequences is limited by the development of viral drug resistance and by host factors. This report summarizes studies published to date on the significance of testing of HIV-1 resistance to antiretroviral drugs. The only Food and Drug Administration-approved kit for HIV drug resistance testing by genotypic sequencing is commercially available through Visible Genetics, Inc. Genotyping sequencing alone is most likely an adequate test to assist in the therapeutic decision-making process for previous regimen failure, for treatment-naïve patients in areas of high prevalence of transmitted resistant virus, and for pregnant women. However, in exceptional cases of highly complex mutation patterns and extensive cross-resistance, it may be useful to obtain a phenotype test, because that result may more easily identify drugs to which virus is least resistant. There are no published clinical trials results on the usefulness of the so-called virtual phenotype over genotypic sequencing alone. Not only has the paradigm of viral pharmacogenomics in the form of HIV genotypic sequencing been useful in treating other viral diseases, but it is also important to the real-life implementation of the growing discipline ofgenomics or molecular medicine. The application of this paradigm to the thousands of potential therapeutic targets that have become available through the various human genome projects will certainly gradually change the landscape of diagnosis and management of many diseases, including cancer.

Anti-HIV Agents↗
PubMed2003

Human immunodeficiency virus type 1 pharmacogenomics in clinical practice: relevance of HIV-1 drug resistance testing (Part 2).

Throughout most of the past century, physicians could offer patients no treatments for infections caused by viruses. The experience with treatment of infection by human immunodeficiency virus (HIV) has changed the way healthcare workers deal with viral infections and has triggered a growing rate of discovery and use of antiviral agents, the first fruits of the expanding genomics revolution. HIV treatment also provides an informative paradigm for pharmacogenomics because control of infection and its consequences is limited by the development of viral drug resistance and by host factors. This report summarizes studies published to date on the significance of testing of HIV-1 resistance to antiretroviral drugs. The only Food and Drug Administration-approved kit is commercially available through Visible Genetics, Inc., for HIV drug resistance testing by genotypic sequencing. Genotyping sequencing alone is most likely an adequate test to assist in the therapeutic decision-making process in cases of previous regimen failure, treatment-naïve patients in areas of high prevalence of transmitted resistant virus, and pregnant women. However, in exceptional cases of highly complex mutation patterns and extensive cross-resistance, it may be useful to obtain a phenotype test, because that result may more easily identify drugs to which the virus is least resistant. There are no published clinical trial results on the usefulness of the so-called virtual phenotype over genotypic sequencing alone. The paradigm of viral pharmacogenomics in the form of HIV genotypic sequencing has been not only useful to the treatment of other viral diseases but also important to the real-life implementation of the growing discipline of genomics or molecular medicine. The application of this paradigm to the thousands of potential therapeutic targets that have become available through the various human genome projects will certainly gradually change the landscape of diagnosis and management of many diseases, including cancer.

Antiviral Agents↗
PubMed2002

Shy-Drager syndrome and severe unexplained intraoperative hypotension responsive to vasopressin.

IMPLICATIONS: We describe the first case of Shy-Drager syndrome diagnosed on the basis of intraoperative hemodynamic changes. The initial hypertension in the supine position followed by severe hypotension after hydralazine administration, ultimately responsive to vasopressin, led to a diagnosis of Shy-Drager syndrome. We suggest that vasopressin may be the drug of choice in patients with Shy-Drager syndrome with refractory hypotension.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Single needle approach for multiple medial branch blocks: a new technique.

BACKGROUND AND OBJECTIVES: Medial branch blocks are an important tool for the diagnosis of facet joint arthropathy. The most commonly used technique involves multiple needle placements, one for each nerve blocked. This multiple needle technique may require a large amount of local anesthetic for anesthetizing the skin, thereby increasing the rate of false-positive blocks. TECHNIQUE: Diagnostic lumbar medial branch blocks are usually performed using multiple needles, one for each branch. The authors describe a different technique using a single needle for all levels. Initially, the needle is directed toward the medial branch located at the level of the affected facet joint in the antero-posterior view. After anesthetizing this nerve with local anesthetic, the same needle is withdrawn to the skin with the tip still in the subcutaneous tissue and repositioned to block the medial branch above, and thereafter below, while continuing to use only the antero-posterior view, thereby using only one entry site. CONCLUSIONS: When performed correctly, the single needle technique provides accuracy similar to the more conventional multiple needle approach during the performance of diagnostic facet joint nerve blocks. Because only one skin entry point is needed, however, this technique may afford several advantages over the multiple needle approach. These may include less patient discomfort, less time required and less radiation exposure since only one C-arm position is used, a smaller volume of local anesthetic, and possibly a lower incidence of false-positive blocks.

Anesthesia, Spinal↗
PubMedDate not supplied

Opioid therapy and immunosuppression: a review.

The idea that opioids modulate the immune system is not new. By the late 19th century, Cantacuzene, used morphine to suppress cellular immunity and lower the resistance of guinea pigs to bacterial infection. While exogenous opioids mediate immunosuppression, endogenous opiates exert opposite actions. Acute and chronic opioid administration is known to have inhibitory effects on humoral and cellular immune responses including antibody production, natural killer cell activity, cytokine expression, and phagocytic activity. Opiates behave like cytokines, modulating the immune response by interaction with their receptors in the central nervous system and in the periphery. Potential mechanisms by which central opiates modulate peripheral immune functions may involve both the hypothalamic-pituitary-adrenal axis and the autonomic nervous system. The presence of opioid receptors outside the central nervous system is increasingly recognized. Those receptors have been identified not only in peripheral nerves but also in immune inflammatory cells. The immunosuppression mediated by opiates may explain the increased incidence of infection in heroin addicts. Opiates may also promote immunodeficiency virus infection by decreasing the secretion of alpha and beta chemokines (important inhibitory cytokines for the expression of HIV) and at the same time increasing the expression of chemoreceptors CCR5 and CCR3, coreceptors for the virus. The fact that peripheral immunosupression is mediated at least in part by opioid receptors located in the central nervous system and that intrathecally administered opioids do not exert the same immunosuppressive effects may have important clinical implications for those patients receiving long-term opioid therapy for malignant and nonmalignant pain.

Cytokines↗