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Biomedical subjects

Michael K Urban

Publications and source records attributed to Michael K Urban.

8 recordsLinked to original sources
PubMed2006

Interscalene block anesthesia at an ambulatory surgery center performing predominantly regional anesthesia: a prospective study of one hundred thirty-three patients undergoing shoulder surgery.

Interscalene block (ISB) of the brachial plexus is frequently used for patients undergoing ambulatory shoulder surgery. We previously reported that the incidence of postoperative complaints (neurapraxia) after an ISB was low (3% at 2 weeks), but objective neurologic assessment was not included in the study. The present study combines subjective findings with both preoperative and postoperative objective sensory and motor assessments after an ISB. We prospectively evaluated 133 patients undergoing elective ambulatory shoulder surgery. ISB anesthesia was accomplished by use of 1.5% mepivacaine alone or in combination with bupivacaine (0.5%-0.75%) via a paresthesia technique and a 23-gauge needle. All of the blocks were performed by experienced anesthesiologists. The number of passes with the needle, site of paresthesia, ease of performing the block, and success of the ISB were recorded for each patient. Neurologic assessment was performed preoperatively and up to 2 weeks postoperatively by 1 of 4 health care professionals but not by the anesthesiologists who performed the ISB and included diminished sensation, localized nerve pain, Semmes-Weinstein monofilament pressure threshold sensibility, Weber static 2-point discrimination, and grip strength changes. Patients with postoperative changes were followed up until resolution of symptoms occurred. Successful surgical anesthesia was achieved in 98% of the patients. There was 1 major perioperative complication (0.7%), a seizure that occurred within 5 minutes of the ISB. Two (1.4%) complained of transient postoperative neurapraxias. Neither patient had any changes in objective sensory and motor measurements. Hence, there was no correlation between subjective complaints and objective findings in this study. This study demonstrates that, in the hands of anesthesiologists doing predominantly regional anesthesia, there is a 1.4% incidence of neurologic complications after an ISB. ISB is a safe and effective technique for patients undergoing ambulatory shoulder surgery when an anesthesiologist experienced with regional anesthesia is involved.

Adult↗
PubMed2006

Pott disease in the thoracolumbar spine with marked kyphosis and progressive paraplegia necessitating posterior vertebral column resection and anterior reconstruction with a cage.

STUDY DESIGN: Case report. OBJECTIVES: To report on a patient with Pott disease, progressive neurologic deficit, and severe kyphotic deformity, who had medical treatment fail and required posterior/anterior decompression with instrumented fusion. Treatment options will be discussed. SUMMARY OF BACKGROUND DATA: Tuberculous spondylitis is an increasingly common disease worldwide, with an estimated prevalence of 800,000 cases. METHODS: Surgical treatment consisting of extensive posterior decompression/instrumented fusion and 3-level posterior vertebral column resection, followed by anterior debridement/fusion with cage reconstruction. RESULTS: Neurologic improvement at 6-month follow-up (Frankel B to Frankel D), with evidence of radiographic fusion. CONCLUSIONS: A 70-year-old patient with progressive Pott paraplegia and severe kyphotic deformity, for whom medical treatment failed is presented. A posterior vertebral column resection, multiple level posterior decompression, and instrumented fusion, followed by an anterior interbody fusion with cage was used to decompress the spinal cord, restore sagittal alignment, and debride the infection. At 6-month follow-up, the patient obtained excellent pain relief, correction of deformity, elimination of the tuberculous foci, and significant recovery of neurologic function.

Aged↗
PubMed2002

Reduction in postoperative pain after spinal fusion with instrumentation using intrathecal morphine.

STUDY DESIGN: The efficacy of intrathecal (spinal) morphine in the treatment of pain after posterior spinal fusions was assessed. OBJECTIVE: To investigate improved posterior pain control with fewer side effects in patients with posterior spinal fusions. SUMMARY OF BACKGROUND DATA: After multilevel spinal fusion with instrumentation, patients experience considerable pain that is difficult to treat. METHODS: For this study, 65 patients undergoing elective multilevel posterior spinal instrumentation were randomized to receive spinal morphine as follows: 10 microgram/kg, 20 microgram/kg, or none. These patients were assessed after surgery for pain control and narcotic-associated complications. RESULTS: The patients who received 20 microgram/kg of spinal morphine were more comfortable immediately after surgery, remained pain free for a longer period, and required significantly less additional narcotic. These patients also had fewer respiratory complications. CONCLUSIONS: Relatively high-dose spinal morphine administration provides simple, reliable postoperative pain control after posterior spinal fusions. This may contribute to reduced postoperative respiratory morbidity and an improved outcome.

Analgesics, Opioid↗
PubMed2002

Two linked hairy/Enhancer of split-related zebrafish genes, her1 and her7, function together to refine alternating somite boundaries.

The formation of somites, reiterated structures that will give rise to vertebrae and muscles, is thought to be dependent upon a molecular oscillator that may involve the Notch pathway. hairy/Enhancer of split related [E(spl)]-related (her or hes) genes, potential targets of Notch signaling, have been implicated as an output of the molecular oscillator. We have isolated a zebrafish deficiency, b567, that deletes two linked her genes, her1 and her7. Homozygous b567 mutants have defective somites along the entire embryonic axis. Injection of a combination of her1 and her7 (her1+7) morpholino modified antisense oligonucleotides (MOs) phenocopies the b567 mutant somitic phenotype, indicating that her1 and her7 are necessary for normal somite formation and that defective somitogenesis in b567 mutant embryos is due to deletion of her1 and her7. Analysis at the cellular level indicates that somites in her1+7-deficient embryos are enlarged in the anterior-posterior dimension. Weak somite boundaries are often found within these enlarged somites which are delineated by stronger, but imperfect, boundaries. In addition, the anterior-posterior polarity of these enlarged somites is disorganized. Analysis of her1 MO-injected embryos and her7 MO-injected embryos indicates that although these genes have partially redundant functions in most of the trunk region, her1 is necessary for proper formation of the anteriormost somites and her7 is necessary for proper formation of somites posterior to somite 11. By following somite development over time, we demonstrate that her genes are necessary for the formation of alternating strong somite boundaries. Thus, even though two potential downstream components of Notch signaling are lacking in her1+7-deficient embryos, somite boundaries form, but do so with a one and a half to two segment periodicity.

Animals↗
PubMedDate not supplied

Pulmonary complications in anterior-posterior thoracic lumbar fusions.

BACKGROUND CONTEXT: Surgery for adult spinal deformity may require both an anterior and posterior approach in order to stabilize the spine and achieve the desired correction. These procedures can be associated with significant pulmonary complications, including atelectasis, pneumonia and respiratory failure. The etiology of some of the respiratory complications is clear: poor inspiratory effort from incision pain and previous pulmonary disease. However, for many patients the direct cause of these complications is not obvious. PURPOSE: To delineate the incidence, severity and risks associated with pulmonary complications in the setting of major spine surgery. STUDY DESIGN/SETTING: Retrospective chart review study of adult patients undergoing combined anterior-posterior thoracic, lumbar and sacral fusion spine surgery. PATIENT SAMPLE: A total of 60 charts were reviewed for this study. OUTCOME MEASURES: Radiographic abnormalities correlated with clinical findings, postoperative need for ventilation and lengths of hospital stay were used as outcome measures. METHODS: Perioperative pulmonary complications were assessed for 60 patients with spinal deformities who underwent combined anterior-posterior thoracic, lumbar and sacral fusion over a 2-year period. RESULTS: One patient was eliminated from analysis because of multiple surgeries during his hospital course. Of the remaining 59 patients, 38 (64%) developed roentgenographic abnormalities. The most common radiographic finding was an effusion found in 66% of these patients, followed by atelectasis in 53%. Twenty-one percent (8 of 38) had infiltrates. Five (5 of 38) or 13% had evidence of partial or complete lobar collapse; in two bronchoscopy was required because of profound hypoxemia. Two patients had pneumonia requiring antibiotic treatment. All but two patients were extubated within 36 hours of surgery. They were kept intubated because of hemodynamic instability. There was no statistically significant difference in the group of patients with and without roentgenographic abnormalities with regard to age, weight, American Society of Anesthesiologists class, smoking history, pulmonary function test results, blood loss, perioperative blood and crystalloid requirement and length of surgery. Patients with radiographic abnormalities were more likely to have had invasion of their thoracic cavity (p=.02) and had a longer mean hospital stay of 13.5 versus 10.2 days (p=.009). CONCLUSION: Radiographic abnormalities of the lungs are common after major spine surgery involving both an anterior and posterior approach, especially when the thoracic cavity is invaded. In view of the morbidity and longer hospital stay associated with such findings, close monitoring of pulmonary status with aggressive pulmonary toilet are indicated.

Adult↗
PubMedDate not supplied

Pulmonary injury in patients undergoing complex spine surgery.

BACKGROUND CONTEXT: Previous reports have shown that 15% of patients who undergo sequential anterior, then posterior, surgical corrections for spinal deformities demonstrate evidence of acute lung injury. By analyzing the bronchoalveolar lavage (BAL) fluid from these patients for evidence of acute inflammation, we might gain some insight into the etiology of this acute lung injury. PURPOSE: To elucidate the etiology of acute lung injury after corrective surgery for adult spinal deformities. STUDY DESIGN/SETTING: Fifteen adult patients with scoliosis scheduled for elective sequential anterior then posterior corrective (A/P) spinal deformity surgery. PATIENT SAMPLE: Consecutive adult patients with scoliosis scheduled for elective corrective surgery with the author (OBA). OUTCOME MEASURES: Patients were assessed for postoperative respiratory complications by oxygen requirements, continued mechanical ventilation, and radiological evidence of diffuse bilateral interstitial or alveolar infiltrates. An acute pulmonary inflammatory response included the presence of inflammatory cells and elevated cytokines in BAL fluid. METHODS: BAL were performed after induction of anesthesia but before surgery, at the completion of surgery, and on the morning after surgery with the patient still intubated. BAL fluid was analyzed for inflammatory cells and cytokine interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) levels. Patients were assessed postoperatively for increased pulmonary vascular resistance, radiological evidence of diffuse bilateral alveolar infiltrates, and the requirement for ventilatory support beyond the first postoperative day (POD1). RESULTS: The cell counts of BAL fluid demonstrated significant increases in neutrophils, lymphocytes, and lipid laden macrophages (LLMAC) with surgery. The concentration of the cytokines IL-6 and TNF-alpha also increased with surgery. The elevations in BAL inflammatory cells and cytokine levels correlated positively with increased pulmonary vascular resistance and the requirement for mechanical ventilation. CONCLUSIONS: After A/P spine fusions, patients have evidence of an acute inflammatory pulmonary injury. Several etiologies exist for this finding, including blood and fluid infusions, direct trauma to the lung, a systemic inflammatory response, and the embolization of fat and bone-marrow debris. The presence of LLMAC in the lungs of these patients and the finding that the patient with the requirement for the longest ventilatory support also had the highest BAL LLMAC count, suggest that the embolization of fat and bone debris released from the spine during surgery may be at least partially responsible for the lung injury. Further studies on the mechanism of lung injury during this procedure are warranted.

Adult↗
PubMedDate not supplied

Lumbar microdiscectomy under epidural anesthesia: a comparison study.

BACKGROUND CONTEXT: Lumbar microdiscectomy is most commonly performed under general anesthesia, which can be associated with several perioperative morbidities including nausea, vomiting, atelectasis, pulmonary aspiration, and prolonged post-anesthesia recovery. It is possible that fewer complications may occur if the procedure is performed under epidural anesthesia. PURPOSE: To investigate the safety and efficacy of epidural anesthesia in elective lumbar microdiscectomies. STUDY DESIGN: A prospective study evaluating the relative morbidities associated with epidural anesthesia and general anesthesia for lumbar microdiscectomy. PATIENT SAMPLE: Forty-three patients scheduled for primary lumbar microdiscectomy. Two cohorts were formed and were studied separately; one observational of all the 43 patients, and a second cohort of 17 patients who agreed to enter in the randomized trial. OUTCOME MEASURES: The clinical outcome was determined by the presence of postoperative pain, the absence of anesthesia-related complications, and the overall postoperative recovery. METHODS: This was a prospective study. With institutional review board approval, 43 consecutive patients were enrolled in the study. However, only 17 patients agreed to be randomized to receive either general or epidural anesthesia for the procedure; the remaining 26 patients selected the type of anesthesia of their preference. Recorded data for all patients included: age; total surgical time; occurrence of nausea, vomiting, atelectasis, or cardiopulmonary complication; ability to arise out of bed on the day of surgery; and the total number of inpatient hospital days. Postoperative pain and satisfaction were assessed only in the randomized cohort. RESULTS: There were a total of 43 patients, with a mean age of 38.1 years. The patients undergoing epidural anesthesia were marginally older than those undergoing general anesthesia. The epidural and general anesthetic groups were not different with respect to surgical time, pain assessed with a linear visual analogue scale, hospital stay, or the likelihood of arising out of bed on the day of surgery. There were no major cardiopulmonary complications in either group. Patients with epidural anesthesia had significantly less nausea and vomiting. CONCLUSIONS: Epidural anesthesia as an alternative to general anesthesia has shown less postoperative nausea and vomiting in lumbar microdiscectomy. Nevertheless, given the small number of patients, this study should be considered as preliminary, showing small differences in minor potential complications.

Adult↗