An office approach to the diagnosis of chronic cough

BACKGROUND: Some cancer patients require invasive techniques for control of chronic cancer pain. Many patients have benefited from local administration of opioids and anesthetics through an epidural catheter. However, epidural abscess and meningitis are side effects of epidural catheters that have serious morbidity and mortality. METHODS: In a retrospective study, the charts of all patients who received an epidural catheter for the management of chronic cancer pain in a 3-year period (1993-1996) were reviewed. Patients with nervous system infections were identified and pertinent clinical, radiologic (magnetic resonance imaging), and bacteriologic data were analyzed. RESULTS: Ninety-one patients received 137 epidural catheters for a total of 4326 catheter days. All but four patients had died at the time of the final analysis. The median survival after placement of the first epidural catheter was 38 days (range, 1 day--> 1000 days). Seventy-two patients received a percutaneous port whereas 19 patients were treated with an implanted subcutaneous port. Adequate pain relief was obtained in 76% of the 58 patients with nociceptive pain and in 73% of 33 patients with neuropathic pain. All neuropathic pain was associated with active tumor and could be classified as nociceptive nerve pain. Technical complications and superficial infections occurred in as many as 43% of patients. Deep infections occurred in 12 patients, 11 of whom had a spinal epidural abscess. CONCLUSIONS: Deep infection is a frequent complication of epidural analgesia and is associated with a high morbidity and mortality. Only cancer patients with a short life expectancy (< or =3 months) should be treated with epidural analgesia.     

A genome-wide scan for human obesity genes reveals a major susceptibility locus on chromosome 10

PURPOSE: To clarify the clinical feasibility of getting a long-term arterial access at the subclavian region by directly puncturing the artery under ultrasound guidance. MATERIALS AND METHODS: Percutaneous placements of arterial infusion catheters with implantable ports were performed in 30 patients with malignant abdominal tumors. The axillary artery in the subclavian region was punctured directly with an 18G needle under ultrasound guidance. Using the Seldinger technique, a 5Fr catheter was placed with its tip in the hepatic or the other tumor-supplying arteries. The catheter was connected to an implantable port, and both of them were embedded in the subcutaneous pocket. RESULTS: Percutaneous placements of infusion catheters were successfully performed in 29 cases. Transarterial chemotherapy through implanted ports was done uneventfully in 26 patients, while in the other three cases, catheter dislodgment occurred. Two local haematomas, one wound infection and one cerebellar infarction were also experienced. CONCLUSION: Ultrasound-guided subclavian approach is a minimally invasive way of implanting an infusion catheter for chemotherapy, although its indication for severely atherosclerotic patients should be limited.     

Splenic arterial portal infusion

A significant number of gynecologic oncologic patients require intravenous chemotherapy. Peripheral venous access frequently becomes difficult, necessitating reliable central venous access. This study was done to retrospectively review our experience with completely implanted venous access ports (ports). There were 100 women from 1984 to 1992 who received 115 ports. These ports remained in situ on average 350 +/- 2.3 days for a total of 110 patient years; 38 ports were in place for more than one year. An average of six courses of chemotherapy were given through each port. There was no statistically significant difference demonstrated in the complication rate secondary to site or side of placement (p = 0.5). Catheter performance in 77 percent of the patients was impeccable. We conclude that implantable ports are a safe and reliable method of chronic venous access in gynecologic oncologic patients requiring intravenous chemotherapy. Although ports reduce the number of complications and manipulations associated with percutaneous catheters, they are not devoid of problems.     

Reliability of the epidural test dose]

Complications associated with epidural anaesthesia include accidental intravascular or subarachnoid epidural catheter misplacement resulting in systemic toxicity and total spinal block, respectively. Epidural test doses are used routinely to prevent these events. It is not known whether the use of test doses improves the safety of epidural anaesthesia. The reliability of the epinephrine test dose in terms of detecting intravascular injection is impaired in elderly patients, patients receiving beta-blockers, patients undergoing vascular surgery, patients under general anaesthesia, and in women in labour. The ability of the epidural test dose to detect subarachnoid injection remains unknown. Studies are needed to determine 1) the reliability of the epidural test dose among different groups of patients, 2) the safety of the test dose, and 3) the incidence of epidural catheter misplacements.     

Infections complicating tunneled intraspinal catheter systems used to treat chronic pain

Tunneled intraspinal catheters and catheter-pump systems are increasingly common treatments for severe chronic pain, but these long-term catheters have caused meningitis, epidural abscesses, and other serious infections. At a cancer referral center, 81 catheters were placed in 72 patients over a 7-year period. There were seven catheter-associated infections: two were meningeal (one was accompanied by an epidural abscess and one by a pocket infection and bacteremia), four were associated with a pocket, and one was associated with a tunnel. The infection rate was 0.77 per 1,000 catheter-days. Pathogenic organisms that were isolated were primarily normal skin flora. By multivariate Cox analysis, the only factor significantly associated with catheter infection was prolonged catheter placement surgery, i.e., a procedure lasting at least 100 minutes (RR, 8.8; 95% CI, 1.6-50). Three patients were cured by removal of the catheter and treatment with antibiotics, and symptoms were satisfactorily suppressed in four patients with antibiotics alone. Considering the severity of illness in catheter recipients, the infection rate was relatively low. Removal of the catheter does not appear mandatory when the goal is suppression of infection-related symptoms, especially when the infection has not spread to the CNS, the infecting organism has an intrinsically low virulence, and the infected patient is terminally ill.     

Hydrothorax caused by intravasal triple-lumen subclavian catheter

A case in which a patient developed right-sided hydrothorax due to extravasal infusion of total parenteral nutrition (TPN) is reported. The catheter was a triluminal catheter and the tip was shown to be correctly placed in the superior vene cava by x-ray after injection of radio-opaque contrast. The most proximal injection port located 4.5 cm from the tip of the catheter was documented to be sited in the superior mediastinum outside the vena cava. The infusion was given through the proximal port of the catheter. The mechanisms underlying this complication are discussed. The case emphazises the need to control the position of all infusion ports regularly when using central venous catheters with more than one lumen.     

Epiduritis after long-term pain therapy with an epidural catheter--review of the literature with a current case report

Patients suffering from vascular disease are often a challenge for the acute pain service. Ischaemia, impaired wound healing, stump and phantom limb pain often require a complex analgesic regimen. Invasive measures such as spinal or epidural catheters can be very helpful but carry the risk of infection, as shown by this case report. A 53-year-old woman with a ten-year history of diabetes developed arterial vascular disease. Her right lower leg had been amputated two years previously. She was now admitted with necroses of the left forefoot. A bypass operation was performed under general anaesthesia. Because of intractable ischaemic pain, she was provided with an epidural catheter by the acute pain service. The bypass occluded, however, and a few days later her left lower leg also had to be amputated, this operation being performed under epidural anaesthesia with bupivacaine. The catheter was subsequently used for postoperative pain control and as a means to prevent phantom limb pain. When signs of superficial catheter infection were noticed days later, the catheter was immediately removed. Intractable pain then developed in the left leg which could not be sufficiently controlled with opioids and NSAIDs, and so a second epidural catheter was inserted one segment rostrally. Several days later the infected vascular prosthesis had to be removed followed by amputation of the thigh, this operation also being performed in epidural anaesthesia. Eleven days after insertion of the first epidural catheter, the patient complained of low back pain and headache. Examination by a neurologist revealed no signs of intraspinal infection. The second epidural catheter dislocated at this point in time and it was decided to introduce a third one, this being the only means to treat the otherwise intractable stump pain. Ten days later meningism, Kernig's sign and leucocytosis developed. NMR tomography detected intraspinal fluid in the epidural space at the dorsal border of the spinal canal. A hemilaminectomy was performed. The spinal epidural space showed signs of inflammation of the adipose tissue, but no pus. A little necrotic material and residues of an old haematoma were removed and the epidural space was lavaged. Specimens taken from the epidural material revealed colonisation with staphylococcus epidermidis, which was sensitive to the broad spectrum antibiotics formerly given to the patient to treat the infection in the left stump. By the next day, all signs of epiduritis had disappeared and the patient recovered completely.     

Chronic catheterization of the epidural space in rabbits: a model for behavioural and histopathological studies. Examination of meptazinol neurotoxicity

A technique of epidural catheterization in rabbits is described. Twelve albino rabbits received a totally implanted epidural catheter system. The system was implanted surgically, and the functioning of the system tested for a period of 3 months. X-ray examinations following epidural contrast injections showed a distribution up to Th4 following 1.5 ml and Th8-9 following 1.0 and 1.25 ml. Epidural injection of lidocaine throughout the study period proved the system to be functioning for all 3 months. Another 12 rabbits were included for the neurotoxicological examinations following epidural catheterization, without any injections (three rabbits), epidural injections of saline (four rabbits) and meptazinol (five rabbits) once a day for 14 days. Histopathological examinations showed a fibrous cocoon, at the tip of the catheter, in all rabbits. In the group of rabbits which did not receive any injections, the cocoon was slightly infiltrated with leukocytes and local depression of the spinal cord was observed in one rabbit. In the saline-injected group this infiltration was more pronounced and in one rabbit it extended into the meninges. Three rabbits showed local depression of the spinal cord and local myelopathy of the white matter in the area adjacent to the cocoon. In the group of rabbits receiving meptazinol, three out of five had local depression and myelopathy of the white matter. In this group these findings were more pronounced. In two rabbits the myelopathy extended transversely through the white matter into the grey matter of the spinal cord. The number of pathological changes in the group receiving meptazinol was significantly higher compared to the control and placebo groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increased anticoagulation during cardiopulmonary bypass by prostaglandin E1

We prospectively evaluated the diagnostic accuracy of an epinephrine-containing epidural test dose (EpiTD) as a marker of intravascular injection in 209 unmedicated laboring women. Maternal heart rate (MHR) was continuously monitored and recorded on a strip chart. A tocodynamometer monitored uterine activity. A lumbar epidural catheter was placed and aspirated. If aspiration was positive for blood or cerebrospinal fluid (CSF), the catheter was replaced. In uterine diastole and with stable MHR, 198 patients received an EpiTD (epinephrine 15 microg plus lidocaine 45 mg) via the catheter. MHR and the generated HR strip were observed. A positive EpiTD was defined as a sudden increase in MHR of 10 bpm more than the resting MHR, within one minute after the injection, with a fast acceleratory phase of more than 1 bpm. Absence of a tachycardiac response suggested a negative EpiTD. If the tachycardiac response was deemed equivocal or a uterine contraction followed the EpiTD injection within 1 min, the EpiTD was invalidated and repeated. Catheter aspiration was repeated, and the catheter was removed if aspiration was positive. All patients with negative EpiTD and aspiration received 6-12 mL of epidural bupivacaine 0.25% with or without fentanyl 50 microg. Absence of analgesia without signs or symptoms of systemic toxicity after a maximum of bupivacaine 30 mg defined failed epidural analgesia. All patients with positive EpiTD and negative aspiration received 5 mL of lidocaine 2% epidurally as a second test dose (Lido100TD). The presence of tinnitus and/or metallic taste defined a positive Lido100TD. There were 176 true negatives, 0 false negatives, 14 true positives, and 8 false positives. The sensitivity of EpiTD was 100%, the specificity 96%, the negative predictive value 100%, and the positive predictive value 63%. The prevalence of negative tests was 88%, and the prevalence of positive tests was 12%. The overall accuracy of an EpiTD was 95.5%. We conclude that EpiTD is a reliable test to identify i.v. catheters during the performance of lumbar epidural analgesia in laboring patients. Implications: Catheters inserted for epidural analgesia in laboring patients may accidentally enter a blood vessel. Local anesthetics injected through these catheters may cause seizures and cardiac arrest. In this study, we concluded that injecting a small amount of epinephrine before injecting a local anesthetic frequently helps to identify these misplaced catheters. Few catheters may actually be in the correct place even after responses to epinephrine.     

Erythrocyte Na/K ATPase activity and diabetes: relationship with C-peptide level

The purpose of this study is to clarify the volume effect of epidural saline injection 20 min after spinal anesthesia. Thirty patients undergoing combined spinal and epidural anesthesia for orthopedic surgery were randomly divided into two groups: a control group (n = 15) and a saline group (n = 15). In the control group, 2% lidocaine 3 ml with 0.4% tetracaine was injected into the subarachnoid space from L 4-5 interspace using Durasafe (Becton Dickinson, USA) and saline was not injected into the epidural space. In the saline group, saline 10 ml was injected through an epidural catheter 20 min after spinal anesthesia. The levels of analgesia 20 min after spinal anesthesia were not significantly different between the groups. However, the levels of analgesia 3, 5, 10, 40 and 100 min after epidural saline injection in the saline group were significantly higher than those in the control group (P < 0.05). The highest analgesic level was obtained 10 min after epidural saline injection and reached to T 4.3 +/- 1.1. In conclusion, epidural saline injection increases the analgesic level 20 min after spinal anesthesia because of the volume effect.     

Neurologic complications after placement of cerebrospinal fluid drainage catheters and needles in anesthetized patients: implications for regional anesthesia. Mayo Perioperative Outcomes Group

Subarachnoid or epidural needle placement in an anesthetized patient is controversial because general anesthesia and muscle relaxation may mask neural trauma. However, placement of a needle or catheter in the subarachnoid space for the purpose of cerebral spinal fluid (CSF) drainage is frequently performed in anesthetized patients undergoing neurosurgery. The records from 530 consecutive transsphenoidal surgeries performed with lumbar CSF drainage were reviewed to determine the types of neurologic complications attributable to spinal drainage and their rates of occurrence. All patients were anesthetized during CSF drain placement. A 19-gauge malleable needle was placed in 473 (89%) patients. Subarachnoid catheters (20- or 16-gauge catheters placed via 18- or 14-gauge epidural needles, respectively) were placed in 17 (3%) patients. In 40 (8%) patients, the type of drain was unspecified. No new neurologic deficits attributable to spinal drain insertion were detected in the immediate postoperative period or within 1 yr of surgery. Thirteen patients developed postdural puncture headache (2.5%, exact 95% confidence interval 1.3%-4.2%); seven required epidural blood patch (1.3%, 0.5%-2.7%). The low incidence (0%, 0.0%-0.7%) of neurologic injury from spinal drain insertion in anesthetized patients from this study is similar to the incidence of neurologic complications historically reported for both CSF drain insertion and spinal anesthesia. Implications: The performance of regional anesthesia in an anesthetized patient is controversial due to the possibility of unrecognized nerve injury. We report no cases of nerve injury caused by the placement of cerebrospinal fluid drainage needles and catheters in 530 anesthetized patients undergoing neurosurgery.     

CT contrast evidence of injectate encapsulation after long-term epidural administration

This case report provides radiographic evidence (CT scan with Iopamidol) to support the development of epidural injectate encapsulation in response to long-term epidural morphine injections via an implanted polyurethane catheter. The patient complained of intense low interscapular pain when the catheter was used for administration of epidural morphine for control of angina. The patient had previously enjoyed 3 months of excellent pain relief following the initiation of epidural morphine via an implanted portal device. The CT scan, with contrast dye injected via the epidural catheter, clearly showed loculation of the injectate and associated indentation of the spinal cord. It is significant to note that the dye in the encapsulated sheath occupied a significant proportion of the spinal canal extending from T7 to T9.     

Complications during and after surgery and childbirth where spinal or epidural analgesia is used. Guidelines for safe practice

When complications and neurological sequelae occur during a spinal or epidural anaesthetic the causes are clearly related to the procedures in the following cases: severe haemodynamic or respiratory derangement, documented needle trauma of nerve fibres, intraspinal haematoma in anticoagulated or heparinized patients, and epidural infection where an infected epidural catheter entry site is documented. A number of well documented cases have been published in which surgery or patient-related pathology were primary causes of "typical" spinal or epidural neurological complications. These emphasize the importance of searching for other risk factors of neurological sequelae after surgery or child birth in cases where there is no obvious deviation from the normal epidural or spinal procedures. Increased focus on the infrequent, but serious complications of these essentially very safe techniques for surgical anaesthesia and pain relief should serve to increase our vigilance, but should not reduce the application of spinal and epidural analgesia. Guidelines are offered for the effective and safe practice of spinal and epidural anaesthesia and pain relief: adequate supervision of trainee anaesthetists, vigilant monitoring for early detection and handling of complications, and trained nurses on surgical wards to monitor and handle patients during epidural analgesia are important. Sufficient readiness for urgent handling of the very rare, but devastating complications of intraspinal bleeding or infection is an absolute necessity.     

The impact of occupation on self-reported cardiovascular morbidity in western Germany: gender differences

Two hundred one consecutive patients with cancer pain who received intrathecal pain treatment between 1985 and 1993 were included in this retrospective study undertaken to test the hypothesis that epidural metastasis is a common cause of "refractory" cancer pain and that its presence may affect the efficacy and the complication rates of intraspinal pain treatment. Fifty-seven (approximately 28%) patients were investigated by metrizamide myelography, computerized tomography (CT), magnetic resonance imaging (MRI), laminectomy, or neurohistopathology. Epidural metastases were found in 40 (70%) and spinal stenosis in 33 (approximately 58%); 7 patients with total and 26 with partial occlusion of the spinal canal. Presence of epidural metastasis affected catheter insertion complications, daily dosages, and complications of the intrathecal pain treatment only when it was associated with spinal canal stenosis (partial or total). During the period of the intrathecal treatment, the patients with confirmed epidural metastasis and total spinal canal stenosis needed significantly (P < 0.05) higher daily doses of opioid (means = 77 +/- 103 versus 22 +/- 29 mg) and intrathecal bupivacaine (means = 65 +/- 44 versus 33 +/- 20 mg) and had significantly (P < 0.05) higher rates (14% versus 0%) of radicular pain at injection and poor distribution of analgesia than those without epidural metastasis and spinal canal stenosis. In contrast, the rate of occurrence of post-dural puncture headache was significantly (P < 0.05) lower in patients with partial (4%) and total (14%) spinal stenosis than in those without (29%). Unexpected paraplegia occurred in four patients and was due to accidental injury during attempted dural puncture (N = 1) and collapse (due to cerebrospinal fluid leakage leading to "medullary coning" of an unknown epidural metastasis (N = 3).     

The efficacy of epinephrine test doses during spinal anesthesia in volunteers: implications for combined spinal-epidural anesthesia

Epinephrine test doses may be administered during combined spinal-epidural anesthesia to determine intravascular placement of epidural catheters. This study was designed to determine systolic blood pressure (SBP) and heart rate (HR) responses to intravenous injection of epinephrine (15 microg) during spinal anesthesia. Twelve volunteers received three spinal anesthetics (lidocaine 100 mg, tetracaine 15 mg, and bupivacaine 15 mg) in a randomized, double blind, cross-over fashion. Epinephrine was administered prior to spinal anesthesia (control), 30 min after injection of spinal anesthesia, and at regression of sensory block to T-10. SBP was measured with a radial arterial catheter and HR with an electrocardiogram. Positive responses were defined as peak increase in SBP > or = 15 mm Hg or HR > or = 20 bpm after injection of epinephrine. Compared with control, peak SBP responses decreased by a mean of 12 mm Hg during spinal anesthesia with tetracaine and bupivacaine (P < 0.05). Peak HR responses decreased by 11 bpm during all three spinal anesthetics (P < 0.05). Incidences of detection of intravenous injection by positive SBP and HR responses ranged from 50% to 100% and were not significantly affected by spinal anesthesia. Spinal anesthesia reduces hemodynamic responses to intravenous epinephrine injection but is unlikely to reduce detection by positive SBP and HR criteria.     

The effect of prior dural puncture on cerebrospinal fluid sufentanil concentrations in sheep after the administration of epidural sufentanil

Sufentanil is a highly lipid soluble opioid that provides potent analgesia when administered in the subarachnoid space. Unfortunately, the penetration of sufentanil into the cerebrospinal fluid (CSF) after epidural administration is poor, and limits its effectiveness for epidural analgesia. Dural puncture may enhance the movement of epidural sufentanil into the subarachnoid space and increase its effectiveness. To determine whether the administration of epidural sufentanil adjacent to a dural puncture results in significantly greater CSF concentrations, 18 adult ewes were studied. Animals in the control group had an epidural catheter placed at the superior border of the pelvis without dural puncture. Animals in the study group had an epidural catheter placed, followed by a dural puncture performed using an 18-gauge Touhy needle. The dural puncture was performed one interspace cephalad to the epidural catheter. One hour after dural puncture, each animal received a loading dose of 0.35 microg/kg of sufentanil (5 microg/mL) through the epidural catheter, followed by an infusion of epidural sufentanil 0.15 microg x kg(-1) x h(-1) for a period of 4 h. After 4 h, CSF was sampled from a site one interspace caudad to the epidural catheter as well as at the cisterna magna. The mean CSF concentration of sufentanil at the level of the pelvis for animals with a dural puncture was 12.1 +/- 3.0 ng/mL compared with 1.8 ng/mL in controls with intact dura. Sufentanil concentrations at the cisterna magna were below the level of detection (0.08 ng/mL) for all animals in both groups. We conclude that an 18-gauge dural puncture significantly increases movement of sufentanil from the epidural to the intrathecal space. This increase in sufentanil concentration at the level of the pelvis was not associated with detectable levels of sufentanil at the brainstem. Implications: This study addresses the effect of dural puncture on spinal fluid concentrations of sufentanil after epidural administration. A sheep model was used to measure drug concentrations in the spinal fluid at the levels of the pelvis and brainstem after epidural administration. Dural puncture significantly enhanced movement of sufentanil into the spinal fluid at the level of the pelvis, but brainstem concentrations were below the level of detection. Analgesic concentrations of spinal sufentanil in the clinical setting, as well as brainstem concentrations associated with respiratory depression, have yet to be defined.     

Treatment of human pulmonary paragonimiasis with triclabendazole: clinical tolerance and drug efficacy

We report the anesthetic management of a patient with aortitis syndrome using combined spinal and epidural anesthesia. A 28-year-old gravida with aortitis syndrome accompanied by faints was scheduled for an urgent cesarean section. Combined spinal and epidural anesthesia was thought to be better for this case in order to monitor the cerebral circulation by her consciousness level and to reduce the hemodynamic change during surgery as compared to spinal or epidural anesthesia alone. After inserting an epidural catheter at the Th 12/L 1 interspace, spinal anesthesia was performed with 1.5 ml of 0.3% dibucaine at the L 4/L 5 interspace. The level of analgesia was under L 1 with the pinprick method 10 min after the spinal anesthesia. Next, 5 ml of 1.5% mepivacaine was injected through the epidural catheter. The level of analgesia reached to Th 6 without major hemodynamic changes. A healthy 2740 g infant was delivered and she had an uneventful recovery. We conclude that combined spinal and epidural anesthesia is useful in a patient with aortitis syndrome undergoing an urgent cesarean section in order to monitor the cerebral circulation by the consciousness level and to reduce the hemodynamic change.     

Usefulness of radiologic monitoring of epidural catheters using epidurography

INTRODUCTION: Peridural analgesia involves a segmental block which at the thoracic level allows for early pulmonary recovery after chest or high abdominal surgery. The approach is difficult in children for reasons related to anatomy, maintenance, insertion of the catheter and dosing. OBJECTIVE: To report the radiologic monitoring of epidural catheter placement by epidurography as a technique for placing the epidural catheter in 17 patients for whom postoperative analgesia was to be provided by the same route. PATIENTS AND METHODS: Eighteen children (aged from 2 to 12) were given general anesthesia followed by epidural anesthesia. After catheterization of the epidural space, 1 or 1-5 ml of contrast was injected. Immediately afterwards an X-ray of the thoracic or lumbar spinal column, as appropriate to each case, was obtained. Epidural analgesia was provided with a mixture of bupivacaine 0.125% and fentanyl, in continuous perfusion or in fractionated doses. RESULTS: Placement of the catheter tip was confirmed in 17 cases by visualization of symmetry and the presence of contrast medium in the epidural space. In one case we observed extravasation of contrast medium, which had invaded the paravertebral space. The course was linear in 17 cases, with no looping. No complications related to injection of contrast medium were observed. CONCLUSIONS: Epidurography provides objective monitoring of tip placement and trajectory of epidural catheters, advantages which argue in favor of more frequent application of this imaging technique.     

Spinal subdural enhancement after suboccipital craniectomy

PURPOSE: To characterize transient intraspinal subdural enhancement (potentially mimicking the subarachnoid spread of tumor) seen on MR images in some children after suboccipital craniectomy for posterior fossa tumor resection. METHODS: Radiologic and medical records of 10 consecutive children who had MR imaging for spinal staging after resection of posterior fossa tumor during a 9-month period were reviewed retrospectively. In addition, one case with similar findings of intraspinal enhancement on spinal staging MR images obtained at another institution was included in the review. RESULTS: Intraspinal enhancement thought to be subdural was seen in four of 10 patients undergoing spinal staging MR imaging 6 to 12 days after surgery. In these four patients, MR studies 50 to 18 days later, without intervening treatment, showed resolution of the abnormal enhancement. A fifth patient (from another institution) with similar intraspinal enhancement underwent CT myelography 4 days later, which showed no subarachnoid lesions. No metastases have developed in any of these five patients during the 2.5- to 3.5-year follow-up period. conclusions: From analysis of the MR appearance and on the basis of prior myelographic experience, we suggest an extraarachnoid, probably subdural, location of this enhancement. Awareness of this phenomenon will reduce the rate of false-positive diagnoses of metastatic disease. Preoperative spinal staging should be considered for patients undergoing suboccipital craniectomy.     

Redistribution of sufentanil to cerebrospinal fluid and systemic circulation after epidural administration in dogs

Due to its higher lipid solubility, sufentanil may be less likely than morphine to migrate rostrally in the cerebral spinal fluid (CSF) and cause delayed respiratory depression following epidural administration. However, early respiratory depression has been reported in patients after relatively large doses of epidural sufentanil. This has been attributed to systemic drug uptake. We used a dog model to investigate the pharmacokinetics and rostral spread of epidural sufentanil in CSF. Sampling catheters were placed in the lumbar subarachnoid space, the cisterna magna, and femoral arteries of six mongrel dogs. Samples of cisternal CSF, lumbar CSF, and blood were drawn at 0, 1, 5, 15, 30, 60, 90, 120, and 180 min after lumbar epidural sufentanil injection. We measured sufentanil concentrations by gas chromatography-mass spectrometry and used the least squares method to a fit tri-exponential function to each sufentanil concentration versus time data set. Paired t-test was used to test for statistical significance. After epidural sufentanil, lumbar CSF concentrations were significantly higher than plasma or cisternal CSF sufentanil concentrations at all assessment times. Sufentanil concentrations were significantly higher in cisternal CSF than in plasma at 30 and 60 min after injection. Sufentanil appeared rapidly in lumbar CSF, reaching a maximum concentration (Cmax) of 57 ng/mL at 6.5 min. In cisternal CSF, a Cmax of 1.2 ng/mL was reached at 21 min, and Cmax in plasma was 0.35 ng/mL at 6 min. The area under the concentration-time curve (AUC) of sufentanil in cisternal CSF was approximately six times higher than the plasma AUC (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)