Paravertebral Injection Research Articles

Intramuscular Oxygen-Ozone Therapy in the Treatment of Acute Back Pain With Lumbar Disc Herniation

Multicenter randomized, double-blind, simulated therapy-controlled trial in a cohort of patients with acute low back pain (LBP) due to lumbar disc herniation (LDH). To assess the benefit of intramuscular-paravertebral injections of an oxygen-ozone (O2O3) mixture. Recent findings have shown that O2O3 therapy can be used to treat LDH that fails to respond to conservative management. However, these findings are based on intradiscal/intraforaminal O2O3 injection, whereas intramuscular-paravertebral injection is the technique used most in clinical practice in Italy and other Western countries. Sixty patients suffering from acute LBP caused by LDH was randomized to an intramuscular O2O3 or control group. Patients were observed up to assess pain intensity, LBP-related disability, and drug intake (15 [V2] and 30 [V3] days after treatment started, and 2 weeks [V4], and 3 [V5] and 6 [V6] months after treatment ended). A significant difference between the 2 groups in the percentage of cases who had become pain-free (61% vs. 33%, P < 0.05) was observed at V6. Patients who received O2O3 had a lower mean pain score than patients who received simulated therapy throughout the observation period. A significant improvement was observed in LBP-related disability in the study group patients when compared with the control group patients. Active O2O3 therapy was followed by a significantly lower number of days on nonsteroidal anti-inflammatory drugs at V2 and V3 and by a lower number of days at V4. No adverse events were reported. Treatment of LBP and sciatica is a major concern. Although the natural history of acute LBP is often self-limiting, conservative therapies are not always effective; in such cases, O2O3 intramuscular lumbar paravertebral injections, which are minimally invasive, seem to safely and effectively relieve pain, as well as reduce both disability and the intake of analgesic drugs.

Prednisolonacetat als Auslöser eines generalisierten urtikariellen Exanthems

We report on a sixty-six year old female patient, who developed a generalized urticarial exanthema 24 hours after paravertebral injection of bupivacainehydrochloride and prednisoloneacetate due to discomfort of the cervical spine. By means of skin tests a delayed-type reaction to prednisolone and budesonide was evaluated. According to the classification of glucocorticoids regarding their cross-reactivity, prednisolone belongs to the contact allergy-group A of steroids and budesonide to the group B. Accordingly, we performed a local, an oral and a subcutaneous challenge with bethametasone-valerate, fluocortolone and betamethasone. By provocation tests, the compounds of the contact allergy-group C and D1 were tolerated without local or systemic complications.

Role of botulinum toxin type A or B in the complex, multimodality treatment of neck and back pain. Experience on a series of 490 patients

Introduction : There are many reports concerning the successful use of Botulinum Toxin (BoNT) for the treatment of myofascial pain and related disorders. Authors report their experience which started as pilot in 1988, in treating chronic neck and back pain due to myofascial pain originating in muscles as anterior scalenus, ileopsoas or superficial muscles as paravertebral and quadratus lomborum usinglocal injections of BoNT. For the procedure it is important to identify the anatomy of muscles. Pain and myofascial syndrome is subacute or chronic. There are trigger points in tight bands of the muscle. Pain is mediated by endorphine, but there is also a component of neurogenic pain. Material and methods : A total series of 490 adults (301 males, 189 females, age 23–79) have been treated during the years 2004–2007 at the Centro Disordini del Movimento e Sindrome di Tourette in Istituto Galeazzi IRCCS, Milan and by one of the authors (MP) at the Pain Center of Policlinico San Marco, Bergamo. A complete anamnestic, clinical and instrumental (CT and MRI, Rx with functional flexion–extension study) evaluation has been conducted in order to rule out structural causes of the syndrome. Echography was also performed in cases in which an abdominal space-occupying lesion had to be excluded. Electromyography was not considered mandatory. Sixty-nine patients were injected at the scalenus complex, 350 at the piriformis and 59 at the ileopsoas muscles, 12 at the quadratus lomborum: 80–150 IU of BoNT (Botox) was injected with a CT-assisted procedure for ileopsoas or piriformis muscles, while EMG monitoring or direct palpation was used for injection into the paravertebral muscles (quadratus lomborum). Clinical picture evolution was documented with a 10-points-based VAS scale, with personal interview with the patient and with a PROLO economic functional evaluation scale. Results : Significant–total relief from pain was documented in 407 (83%) patients, little improvement was documented in 49 (10%), while 34 (7%) patients did not experience any improvement. No side effects were reported. Medical treatment with NSAIDS was routinely performed for 7 days during the postoperative period. Conclusions : The exact etiology of myofascial back pain still has to be determined: BoNT injection provides relief by direct reduction of muscle spasm, interference with the fuse–receptor loop, and impairment of sympathetic transmission. BoNT represents an interesting and safe tool for the management of patients with myofascial pain. A stretching program is mandatory for 6 weeks after the procedure. A well-experienced operator is mandatory when performing this procedure.

(228) Repetitive paravertebral nerve block using a mixture of ketamine, bupivacaine and methylprednisolone for pain relief in intractable post herpetic neuralgia

We present a case of postherpetic neuralgia (PHN) treated successfully with repetitive paravertebral blocks (PVB) with bupivacaine, ketamine and methylprednisolone. A 65-yr-old male patient, ASA II, weight 55 kg, previously healthy was referred with 24 month left sided parietal chest pain diagnosed as PHN with 8–9/10 on VAS scale. Previous pain treatment included non-steroidal anti-inflammatory drugs and tramadol, combined with oral oxcarbazepine 600 mg per day and amitryptyline 75 mg per day with no improvement. A few months later, gabapentin was added at a dose of 300 mg three times per day that was increased gradually to 1800 mg per day over a 6 month period. Upon presentation, the patient was still complaining of persistent pain with a VAS 8-9/10 in the left thoracic region mainly at T4 extending to T7 associated with mood changes and sleep disturbance. Physical examination revealed an allodynia and hyperaesthesia of the corresponding dermatomes. A unilateral left sided paravertebral block at T4–T5 levels was performed with 20 ml of bupivacaine 0.125% in ketamine 25 mg and methylprednisolone 80 mg. Sedation was achieved with midazolam 2-4 mg. Three more PVB injections were given on weekly interval with the same mixture in 40 mg of methylprednisolone. Blood pressure, ECG, and SpO2 were continuously monitored throughout the procedure and for two hours in the recovery room. There were no serious complications. The patient obtained satisfactory pain relief (VAS 3) over a 6 month follow-up period. Our report showed that weekly paravertebral injections of a mixture of bupivacaine, ketamine and methylprednisolone for 4 weeks resulted successfully in sustained pain relief for PHN.

Comparison of the Hemodynamic Effects of a Single 5 mg/kg Dose of Lidocaine With or Without Epinephrine for Thoracic Paravertebral Block

Epinephrine is often added to local anesthetic solutions to minimize and slow the systemic absorption of local anesthetics, and thus reduce the possibility of adverse effects of these drugs. In an earlier study we found that the injection of 5 mg/kg of lidocaine via the paravertebral route depressed myocardial contractility by up to 30%, with practically no changes in heart rate or blood pressure. In the present study we investigated whether these alterations are due to systemic absorption of the local anesthetic, and whether such absorption can be minimized by adding epinephrine to the local anesthetic solution. A prospective, blind, and randomized study was made of 50 patients subjected to lung resection surgery. The subjects were divided into two groups: Lid group (5 mg/kg bolus dose of lidocaine in the thoracic paravertebral space) and Lid+E group (addition of 5 mcg/mL of epinephrine to the local anesthetic). The anesthetic solution was administered through a paravertebral catheter ipsilateral to the operative side. In addition to routine hemodynamic monitoring (heart rate and radial artery blood pressure), an aortic transpulmonary thermodilution catheter was inserted into the femoral artery for recording of the following variables: cardiac index, cardiac function index, maximum pressure derivative, global end diastolic volume, and intrathoracic total blood volume index. Data collection was carried out immediately before administration of the anesthetic solution and 15, 30, and 45 minutes after administration. Measurements were made of the plasma lidocaine levels at those same postparavertebral injection time points. Prior to paravertebral dosing there were no differences in terms of the hemodynamic variables studied. However, 15 minutes after dosing in the Lid+E group, lesser reductions in contractility, cardiac function index, and cardiac index were recorded, compared with the Lid group, with a significant reduction in cardiac filling volumes. Blood lidocaine levels were 53% and 34% lower in Lid+E group, as recorded 15 and 30 minutes after injection. The patients who, 15 minutes after paravertebral injection, had blood lidocaine levels greater than 3 mcg/mL (independently of the type of anesthetic solution used) had a significant reduction in mean blood pressure, cardiac function index, cardiac index, and maximum pressure derivative, compared with the patients with lower blood lidocaine concentrations. Addition of epinephrine to lidocaine when performing thoracic paravertebral block, attenuates the cardiodepressive effects associated with the systemic absorption of lidocaine and also, as a result of the beta-adrenergic consequences of epinephrine, systemic absorption from the paravertebral space.

Unusual case of camptocormia triggered by lumbar-disc herniation

A 21-year-old male patient with low back pain and marked forward bending was presented. The exaggerated lumbar flexion was preventing him to stand in erect posture but disappeared while lying. The symptoms had begun after he had lifted a heavy object. Straight-leg-raising test could not be performed properly because of the exaggerated pain. The light-touch sense was decreased on L5 and S1 dermatomes. There was no loss of muscle strength. The deep-tendon reflexes were normal. Plain graph showed mild narrowing in the L4-5 and L5-S1 intervertebral spaces. Lumbar magnetic resonance imaging revealed disc protrusions in L4-5 and L5-S1 levels. During his stay in the department, the patient was given tizanidine and tramadol, and physical therapy was performed. A paravertebral intramuscular injection with lidocaine was applied. Moreover, the patient was referred to psychiatrist for evaluation regarding his medical history of conversive seizures and possible efforts for secondary gain. No response was obtained from all the treatments. The final diagnosis was camptocormia triggered by lumbar-disc herniation. He was applied supportive psychotherapy, psychoeducation regarding secondary gain, strong suggestions to improve posture, positive reinforcement, and behavioral therapy. His postural abnormality resolved and disappeared completely with mild pain.

Thoracic Paravertebral Block for Breast Cancer Surgery: A Randomized Double-Blind Study

We examined in this randomized, double-blind study whether a multilevel paravertebral block performed before general anesthesia with propofol and a laryngeal mask enhances postoperative analgesia after breast cancer surgery. Eighty-eight patients were randomized to receive paravertebral injections with either ropivacaine 0.5% (30 mL) or an equivalent amount of isotonic saline. Nine patients were excluded after randomization, thus 79 patients remained for evaluation (ropivacaine, n = 38; placebo, n = 41). Variables of efficacy were the amount of fentanyl delivered by the patient-controlled analgesia device in the postanesthesia care unit (PACU), postoperative pain measured on a numeric rating scale at regular intervals from the day of surgery and until the second postoperative day. The median consumption of fentanyl in the PACU was less in the ropivacaine group compared with the placebo group (0 microg [range: 0-250 microg] versus 100 microg [range: 0-800 microg], P = 0.001). Also, fewer patients in the ropivacaine group reported pain > or =3 on the numbers rating scale in the PACU (13 vs 31, P < 0.0001). No statistical difference in pain scores or consumption of analgesics could be demonstrated after discharge from the PACU. A multilevel paravertebral block provides good analgesia for breast surgery, but the duration of analgesia is briefer than described in previous studies.

Complications of spinal injections

Spinal injections are frequently performed for the relief of pain. These injections include both interlaminar and transforaminal approaches to the epidural space, spinal injections, and paravertebral injections. Frequently steroids are used, but neurolytic procedures may be performed as well. These injections have a good safety record, but a thorough understanding of the possible complications will improve patient safety even further. The goal of this article is to discuss these complications, including infections, hematomas, compromise of the vascular supply to the spinal cord, and reactions to contrast or corticosteroids.

Fulminating Septicemia Secondary to Oxygen-Ozone Therapy for Lumbar Disc Herniation

A case report and clinical discussion. To describe a rare but fatal complication secondary to oxygen-ozone therapy for the treatment of herniated lumbar disc. Previously reported complications secondary to oxygen-ozone therapy are rarely reported. Septic discitis and epidural abscesses have been reported after myelography, lumbar puncture, paravertebral injections, epidural anesthesia, acupuncture, and intradiscal therapy with chymopapain. We report the first case of a local infection with systemic fatal dissemination secondary to this treatment. A 57-year-old man previously treated with oxygen-ozone therapy presented low back and bilateral pain. The lumbar computed tomography revealed the presence of L4-L5 and L5-S1 herniated discs. Three days after admission in the hospital, the patient developed a fulminant septicemia. An abdominal-pelvic and chest computed tomography and blood culture led to the diagnosis of pyogenic lumbar muscle involvement, accompanied with septic pulmonary embolism secondary to Escherichia coli infection. This case report identifies a rare and fatal complication of oxygen-ozone therapy in the treatment of a herniated lumbar disc. Acute fatal septicemia should be considered among the major complications of the oxygen-ozone therapy in the treatment of a herniated lumbar disc.

Sensory blockade after thoracic paravertebral injection of ropivacaine or bupivacaine

No clinical trials comparing the characteristics of sensory blockade caused by various local anaesthetics in thoracic paravertebral blockade have been published. The aim of this prospective study was a clinical assessment of sensory blockade after paravertebral injection of ropivacaine or bupivacaine in patients undergoing modified radical mastectomy. Seventy ASA I-II patients were randomized to receive a single injection of ropivacaine 0.5% (n = 35) or bupivacaine 0.5% (n = 35) at the T4 level. General anaesthesia with propofol and fentanyl was provided during the procedure and patients were not intubated. The following parameters were analysed: duration and dynamics of the sensory blockade and the patient's and surgeon's assessment. Both ropivacaine and bupivacaine provided a similar level of analgesia. Ropivacaine was characterized by more rapid onset - after only 5 min 53% of patients in this group had the extent of sensory blockade wide enough to perform modified radical mastectomy in comparison to only 20% after bupivacaine (P 9 segments blocked) was noted more often in the ropivacaine group (88% vs. 65%, P < 0.05), lasted longer and appeared to be wider than sensory blockade produced by bupivacaine. Regression of sensory blockade was initially similar, but after 24 h sensory blockade in the ropivacaine group still had a potential to provide analgesia for modified radical mastectomy in 81% of patients in comparison to only 50% of such patients in the bupivacaine group (P < 0.05). Degree of postoperative pain, performance of the cardiovascular system, consumption of medications and complications were all similar between the study groups. Both agents provide satisfactory conditions for mastectomy, but ropivacaine seems to be superior to bupivacaine for thoracic paravertebral blockade during breast cancer surgery.

Permeability of Injured and Intact Peripheral Nerves and Dorsal Root Ganglia

Nerve injury that produces behavioral changes of allodynia and hyperalgesia in animals is associated with electrophysiologic changes in dorsal root ganglion (DRG) cells. The introduction of drugs into the DRG or the peripheral nerve that alter calcium, sodium, or potassium channel activity may be of therapeutic benefit after nerve injury. For this reason, the authors sought to determine whether drugs that do not ordinarily cross the blood-nerve barrier will enter the DRG after intravenous or regional injection and to determine whether nerve injury alters drug access to DRGs or peripheral nerves. Both intact and spinal nerve-ligated rats were injected with sodium fluorescein by intravenous, intrathecal, peri-DRG, perisciatic, and epidural routes. DRG, sciatic nerve, and spinal cord tissues were harvested and frozen, and histologic sections were analyzed quantitatively for tissue fluorescence. In both intact and nerve-injured animals, fluorescein accumulated in DRGs after intravenous, peri-DRG, and epidural injection. There was accumulation in the proximal portion of the ganglion after intrathecal injection. Minimal amounts of fluorescein were found in the sciatic nerve in intact animals after intravenous or perineural injection, but substantial amounts were found in some nerve fascicles in nerve-injured animals after both intravenous and perineural injection. There was almost no fluorescein found in the spinal cord except after intrathecal administration. In both intact and nerve-injured animals, fluorescein accumulates freely in the DRG after intravenous, epidural, or paravertebral injection. The sciatic nerve is relatively impermeable to fluorescein, but access by either systemic or regional injection is enhanced after nerve injury.

Thoracic Paravertebral Block: Influence of the Number of Injections

The purpose of this study was to assess the radiographic and clinical distribution of 1 to 4 paravertebral injections by use of the same total volume of local anesthetic mixture. Sixty-nine patients scheduled for surgical interventions suitable for bilateral PVB were included in the study and were randomly assigned to 1 of 3 treatment groups. Group 1 received 4 paravertebral injections on one side versus 1 injection on the contralateral side (23 patients), group 2 received 4 injections versus 2 injections (23 patients), and group 3 received 4 injections versus 3 injections (23 patients). Sixty-one patients were included in the final analysis, which resulted in 368 thoracic paravertebral injections. Overall, 97% of the patients had adequate loss of sensation within the targeted area at the side of 4 injections, compared with only 11% for the single injections. The average vertical spread of contrast was found to be significantly greater in the set of 4 injections, with mean (SD) 6.5 (2.01) dermatomes, compared with the single injection, with 3.0 (1.19) dermatomes (P < .05). The average vertical spread of contrast and complete absence of sensation were significantly greater in the set of 4 injections compared with the set of 2 and 3 injections (P < .05). The main finding of the present study was that multiple paravertebral injections resulted in more reliable radiographic and clinical distribution compared with a single-injection technique.

Efficacy of Single-dose, Multilevel Paravertebral Nerve Blockade for Analgesia after Thoracoscopic Procedures

Although video-assisted thoracoscopic surgery for pulmonary resection is increasingly chosen over thoracotomy, the optimal analgesia regimen for thoracoscopy is unknown. The purpose of this trial was to compare the efficacy of analgesia from preoperative bupivacaine paravertebral nerve blockade with that from placebo injections. Eighty adult patients undergoing unilateral thoracoscopic procedures were enrolled in a prospective, double-blinded, randomized clinical trial of preoperative, multilevel, single-dose paravertebral nerve blockade. Patients received six paravertebral injections with 5 ml of either 0.5% bupivacaine with 0.0005% epinephrine (treated, n = 40) or preservative-free saline (control, n = 40). Cumulative weight-adjusted intraoperative fentanyl and postoperative patient-controlled morphine usage, visual analog pain scores, and spirometry were used to compare efficacy of analgesia between groups. The treated group received significantly less intraoperative fentanyl compared with the control group (P = 0.003) and had a 31% smaller cumulative patient-controlled morphine dose (P = 0.03) in the 6 h after block placement. Within 6 h, treated patients also reported lower maximum pain scores (P = 0.02) and demonstrated less pain score variability (P = 0.01). No statistically significant difference in cumulative morphine usage existed at 12 or 18 h after block placement. No significant difference in spirometry, cortisol levels, or cytokine production was found between treatments. Single-dose paravertebral nerve blockade with bupivacaine is effective in reducing pain after thoracoscopic surgery, but only during the first 6 h after nerve blockade. Because of the limited duration of effect with currently available local anesthetic agents, the current data suggest that, at present, this technique is not indicated in the setting of thoracoscopic surgery.

Arterial and Venous Pharmacokinetics of Ropivacaine with and without Epinephrine after Thoracic Paravertebral Block

Animal and volunteer studies indicate that ropivacaine is associated with less neurologic and cardiac toxicity than bupivacaine. Ropivacaine may offer advantages when used for thoracic paravertebral block. This study was designed to describe the pharmacokinetics of ropivacaine after thoracic paravertebral block. Twenty female patients undergoing elective unilateral breast surgery were randomly assigned to receive a single bolus thoracic paravertebral injection of 2 mg/kg ropivacaine, with or without 5 mug/ml epinephrine. Simultaneous arterial and venous blood samples were obtained for plasma ropivacaine assay. Data were analyzed with NONMEM, using two possible absorption models: conventional first-order absorption and absorption following the inverse gaussian density function. Epinephrine reduced the peak plasma concentrations and delayed the time of peak concentration of ropivacaine in both the arterial and venous blood. The time course of drug input into the systemic circulation was best described by two inverse gaussian density functions. The median bioavailability of the rapid component was approximately 20% higher when epinephrine was not used. The mean absorption times were 7.8 min for the rapid absorption phase and 697 min for the slow absorption phase, with wide dispersion of the absorption function for the acute phase. The half-time of arterial-venous equilibration was 1.5 min. The absorption of ropivacaine after thoracic paravertebral block is described by rapid and slow absorption phases. The rapid phase approximates the speed of intravenous administration and accounts for nearly half of ropivacaine absorption. The addition of 5 mug/ml epinephrine to ropivacaine significantly delays its systemic absorption and reduces the peak plasma concentration.

Neuropathic scrotal pruritus: Anogenital pruritus is a symptom of lumbosacral radiculopathy

Anogenital pruritus is defined as an itch localized to the anus, perianal, and genital skin. Anogenital pruritus is usually a symptom of an underlying disorder of the skin or mucosa or a consequence of anorectal pathology. When no demonstrable cause is found, anogenital pruritus is often described as "idiopathic". To investigate the role of lumbosacral radiculopathy in the pathogenesis of anogenital pruritus. Included in the study were consecutive patients with anogenital pruritus. Radiographs and nerved conduction studies were performed in all patients. Needle electromyography studies and computerized tomography were performed when necessary. Nerve conduction studies included measurement of distal sensory and motor latency, conduction velocity, and F-responses of the peroneal and tibial nerves. Patients with confirmed radiculopathy were treated with paravertebral injection of a mixture of triamcinolne acetonide and lidocaine. Response to the injections was assessed using visual analogue scales by the patients. Mean scores before and after treatment were compared using paired t tests. Included in the study were 20 patients with anogenital pruritus. There were 18 men (90%) and 2 (10%) women. The mean age was 52.7 years (standard deviation [SD] 11.7 years). In 16 patients (80%), radiographs demonstrated degenerative changes of the lower spine. In 16 patients (80%) the presence of lumbosacral radiculopathy was confirmed by nerve conduction studies. Fifteen patients (75%) were treated with paravertebral injections, with significant decrease in mean pruritus score as assessed by the patients (6.3 [+/-2.8]; 4.5 [+/-2.7], before and after treatment, respectively, P = .033). "Idiopathic" anogenital pruritus may be attributable to lumbosacral radiculopathy. Paravertebral blockade may be used for alleviation of symptoms in patients with anogenital pruritus.

Extensive abscess formation after repeated paravertebral injections for the treatment of chronic back pain

Paravertebral injections are commonly used for the treatment of chronic back pain despite the lack of evidence for their efficacy. Here, we report a case in which repeated paravertebral injections of local anesthetics, corticosteroids and botulinum toxin resulted in extensive abscess formation involving the entire paravertebral musculature descending to the level of the midthighs. These abscesses induced a systemic inflammatory response syndrome and required surgical drainage as well as broad-spectrum antibiotic therapy.

Continuous percutaneous paravertebral block for minimally invasive cardiac surgery

p OSTOPERATIVE PAIN after thoracotomy is managed by a number of modalities, including thoracic epidural analgesia (TEA), intercostal block (ICB), interpleural block, and paravertebral b l o c k y Although most regional blocks need to be inserted before surgery, Sabanathan et aP have described a technique of stripping the pleura posteriorly via the surgical incision to position a catheter in the paravertebral space after thoracotomy for infusion of local anesthetics. This technique, in some studies, has been documented to be as good as TEA, the latter being the gold standard for postthoracotomy analgesia.1 Minimally invasive direct coronary artery bypass graft surgery (MIDCABG) without the aid of cardiopulmonary bypass (CPB) is performed more frequently using a minithoracotomy. In the authors' institution, patients come in as a same day admit on the morning of surgery. These patients are extubated on the operating table at the end of anesthesia and are discharged home 48 to 72 hours later. To optimize benefits from such surgical fast-tracking, the anesthesia and analgesia have to be titrated. The authors are currently evaluating TEA for MIDCABG surgery, comparing it with continuous ICB inserted by the surgeon at the end of surgery using the technique described by Sabanathan et al. 3 It is difficult to strip the parietal pleura posteriorly adequately through the small anterior thoracotomy and to insert the catheter far enough posteriorly to position the catheter closer to the paravertebral area (Fig 1). Because ICB is initiated only at the end of surgery, the patients in this group, compared to the TEA group, required higher doses of intraoperative fentanyl (TEA = 269 _+ 120 ~g v ICB = 1,160 + 539 pg), nitroglycerin (TEA = 4,089 -+ 2,863 pg v ICB = 7,953 -+ 5,174 ~tg), and morphine (TEA = 0 v ICB = 6.3 _+ 5.8 mg) 6 as well as requiring higher end-tidal concentrations of isoflurane to achieve hemodynamic control during the intense surgical stimulation associated with thoracotomy. All of these factors may contribute to the need for postoperative ventilation. In view of this experience, the authors believe that insertion of the paravertebral block before surgical incision may facilitate early extubation. Rather than continuous infusion, multiple paravertebral injections from T1 to T8 are used for breast surgery, 4 which encompasses a similar dermatomal segment as minithoracotomy for MIDCABG. Single injections are inadequate for the 24 to 36 hours' duration of analgesia required after MIDCABG. This article reports the use of a continuous paravertebral catheter inserted percntaneously just before surgery for pain relief after MIDCABG via minithoracotomy.

Artificial Displacement of Kidneys, Spleen, and Colon by Injection of Physiologic Saline and CO 2 as an Aid to Percutaneous Procedures: Experimental Results

To determine whether displacement of the kidneys, spleen, or bowel with injection of fluids or CO2 can be used to create a direct and potentially safer access route to the retroperitoneum for large-bore needle biopsy or abscess drainage. In cadavers (n = 24), the kidneys were displaced laterally by means of computed tomography (CT)-guided paravertebral injection of 120 mL of physiologic saline solution (n = 18) and 120 cm3 of CO2 (n = 6). The spleen (n = 11) and retroperitoneal colon (n = 7) were also displaced with saline. Displacement of the organs from the needle tip was measured on CT scans. After fluid injection the kidneys shifted 1.47 cm +/- 0.51, the spleen shifted 1.14 cm +/- 0.44, and the retroperitoneal colon shifted 1.38 cm +/- 0.37. The kidneys obstructed access to the para-aortic space in 17% of cases (four of 24 cases) and to the entire adrenal gland in 72% (13 of 18 cases) before saline injection and in 0% (zero of 24 cases) and 39% (seven of 18 cases), respectively, after injection. The result with fluid were significantly better than those with CO2 (P < .05). Displacement of kidneys, spleen, or retroperitoneal colon with a saline injection is effective in gaining an access route for biopsy or abscess drainage. Potential for patient discomfort, decrease in target-lesion conspicuity, and adverse effects of absorbed fluid in patients with kidney or heart disease must be considered with use of this technique in the clinical setting.

Iatrogenic Compressive Lumbar Myelopathy and Radiculopathy in Adult Cattle following Injection of an Adjuvanted Bacterin into Loin Muscle: Histopathology and Ultrastructure

Compressive lumbar myelopathy is a recognized iatrogenic complication of injecting water-in-oil vaccines into paravertebral sites of laboratory animals and chickens. Herein, we report the histologic and ultrastructural features of a similar complication in a herd of cattle. Iatrogenic posterior paresis developed over 34 days in 56 of 610 cows (9.2%) following injection of a commercial bacterin 11-34 days earlier into M. longissimus lumborum. The bacterin was composed of inactivated Escherichia coli and Campylobacter fetus ssp. venerealis in a proprietary adjuvant. Tissues were collected for histopathology from 9 affected cattle that died or were euthanized after clinical signs lasting 6-38 days. A range of tissues, including the injection site lesion and lumbar spinal nerve roots, was obtained for ultrastructural examination from a cow with paresis of 31 days duration. There was locally extensive pyogranulomatous myositis with fibrosis and necrosis in right M. longissimus lumborum. Extension of the lesion into the vertebral canal via spinal nerve foramina resulted in focal pyogranulomatous inflammation in epidural fat and in adjacent dura mater. There was axonal degeneration in dorsal, lateral, and ventral columns and chromatolysis of spinal motor neurons in lumbar spinal cord, secondary to compression. A distinctive histologic and ultrastructural feature of pyogranulomata was the presence of osmiophilic material at the center of inflammatory foci, surrounded by macrophages and giant cells that contained intracytoplasmic lipid droplets. Ultrastructural examination of entrapped spinal nerves revealed axonal degeneration and loss of myelinated and unmyelinated fibers, segmental demyelination with remyelination, axonal spheroid formation, and early axonal regeneration.(ABSTRACT TRUNCATED AT 250 WORDS)

A thermographic study of paravertebral analgesia

Six patients undergoing paravertebral blocks for chronically painful conditions of the chest wall were thermographically imaged so that the extent of cutaneous vasodilatation and hence sympathetic block could be correlated with the distribution of the somatic block. All blocks were performed by a single experienced operator, with a single percutaneous entry, using 15 ml of 0.5% bupivacaine at a mean level of T9-10 (range T7-8--T10-11), with radiological confirmation of correct needle placement. There was a mean distribution of the somatic block of five dermatomes (range 1-8), as evidenced by loss of pinprick sensation, with upper and lower limits of T6 and L3. The mean distribution of the sympathetic block was eight dermatomes (range 6-10), as evidenced by ipsilateral skin warming (p = 0.0005-0.001), with upper and lower limits of T5 and L3. No bilateral spread was observed. No significant postural changes in blood pressures were seen, although there was a small but significant decrease in supine heart rate (p = 0.05). This study demonstrates that a large unilateral somatic and sympathetic block is obtainable with a single thoracic percutaneous paravertebral injection. It challenges the suggestions that this method of analgesia is ineffective and hazardous, that a sympathetic component is a rare accompaniment and that the lumbar nerve roots are spared.