Intrathecal therapy for cancer and nonmalignant pain: patient selection and patient management.

Intrathecal drug delivery improves pain relief, reduces suffering, and enhances quality of life in the small proportion of patients who do not respond well to oral analgesics, including oral morphine. Although morphine is the "gold standard," and the only drug approved for intrathecal pain therapy in the United States, off-label use of alternative agents appears promising, particularly in patients with neuropathic pain. Careful patient selection and management are significant determinants of successful treatment outcomes. Patient selection criteria for cancer and nonmalignant pain are similar; however, a more comprehensive psychological and social assessment is required for patients with nonmalignant pain. In addition, all patients (those with cancer or nonmalignant pain) must exhibit a positive response to an epidural or intrathecal screening test. A multidisciplinary team approach, involving psychologists, nurses, physical therapists, social workers, and spiritual leaders should be used to manage patients. Current practices for patient selection and management, screening tests, and dosing guidelines for intrathecal drug delivery systems are discussed.

Psychological variables associated with outcome of spinal cord stimulation trials.

Study Design. This is a prospective study designed to identify psychological factors associated with response to spinal cord stimulation (SCS) trial. Summary of Background Data. In most centers, implantation of a permanent SCS system is preceded by a trial of a temporary stimulating electrode. Yet, even among those who report greater than 50% pain reduction during trial, a significant number of these patients fail to receive long-term pain relief from the permanent system. Because mood disorders can alter pain report, we hypothesized that refined definition of the psychological factors associated with SCS success could result in improved selection of candidates for SCS trial. Methods. The study sample consisted of 43 chronic pain patients (72% failed back surgery syndrome, 77% with radiating low back pain) who were referred for implantable pain management. Following psychological evaluation, patients were admitted for a three-day inpatient trial of SCS. Report of at least 50% pain relief during trial was considered a success and resulted in implantation of the permanent stimulator. Patients were retrospectively divided into two groups: those whose pretrial pain was relieved by at least 50% ("success") and those whose pain was relieved by less than 50% ("failure"). Results. Univariate t-test or chi-square analyzes of group means of an extensive psychological battery followed by a global, stepwise logistic regression model of trial outcome was used to analyze between group results of a psychological test battery. MMPI depression and mania subscores were found to be significantly elevated among the two outcome groups (p = 0.007 and 0.025, respectively). Conclusions. Patient mood state is an important predictor of trial outcome. Specific indicators of SCS trial outcome are the MMPI depression and mania subscale scores with successful trials being associated with individuals who are less depressed and have higher energy levels.

Clinical realities and economic considerations: economics of intrathecal therapy.

The estimated annual cost of medical management of chronic back pain is $25 billion. Such management is often ineffective and overly costly. Most physicians who have employed intrathecal pain therapy attest to its efficacy in the management of intractable chronic pain. However, few economic analyses are available to evaluate the cost effectiveness of different modalities and to aid in clinical decision making and third-party reimbursement policies. Current analyses tend to focus on short-term cost-benefit measurements and to ignore variables such as quality of life and patient functioning. This bias has impaired the ability of payers to make appropriate decisions regarding the safety, cost effectiveness, and efficacy of intrathecal pain therapy in noncancer patients. Clinical data demonstrate that for cancer patients whose expectancies exceed 3 months, the overall costs of intrathecal pain therapy may be less than those of tunneled epidural catheters or external infusion devices. In nonmalignant pain, intrathecal therapy appears to be cost effective compared to conventional medical management at 22 months. Further debate and fine tuning of these economic models from all perspectives are required.

Epidural opioid therapy for chronic nonmalignant pain: critique of current experience.

The current use of epidural catheter techniques for nonmalignant pain follows directly from its successful use of treating intractable malignant pain states. Long-term studies are confirming the safety of epidural infusions of morphine and local anesthetics. Limitations of this technique related to technical catheter considerations, neuropathic pain states, and cost considerations are being reevaluated as more information is developed. Epidural infusions in nonmalignant pain may prove their value in prolonged treatments for conditions that may resolve in time. They are also being utilized increasingly as screening tools prior to implanting permanent infusion pump systems.

Intrathecal narcotics for relief of pain from head and neck cancer.

We describe our experience with nine patients with head and neck pain of malignant origin who were treated with continuous low-dose intrathecal morphine via a lumbar catheter and implantable subcutaneous drug delivery pump. All patients had failed prior attempts at oral narcotic pain control due to either poor pain control or intolerable side effects. Using a visual analogue scale where the most severe pain is rated as 10 and no pain is rated as 0, the mean visual analogue scale was reduced from 7.6/10 (range, 5 to 10/10) before implantation to 1.9/10, 2.0/10, and 0.5/10 at 1 week, 1 month, and 2 months after implantation, respectively. Complications were acceptable. We conclude that intrathecal administration of morphine is a safe and effective means of pain control. This method deserves serious consideration in patients with intractable pain secondary to head and neck malignancy.

A comparison of patient-controlled analgesia and bolus PRN intravenous morphine in the intensive care environment.

We compared the use of patient-controlled analgesia (PCA) morphine and p.r.n. intravenous morphine in an intensive care unit setting. Thirty-eight patients scheduled for admission to the Surgical Intensive Care Unit (SICU) were prospectively randomized to either a PCA group or a p.r.n. intravenous morphine group. Assessments included pain and sedation scores, respiratory rates, pulse oximetry, and morphine utilization. PCA was found to be comparable in safety and efficacy to nurse-administered morphine in the intensive care environment. An unexpected finding was the higher initial morphine utilization seen in the patients utilizing PCA.

Cost analysis of two implantable narcotic delivery systems.

This survey compares costs of two commonly utilized implantable narcotic delivery systems. The systems are classified into type-I (exteriorized system using the DuPen epidural catheter) and type-II (implanted system using the Synchromed pump). Costs were analyzed by reviewing actual patient hospital financial service records and Homecare vendor quotations. From the perspective of cost analysis alone, we conclude that savings accrue when patients requiring treatment beyond 3 months duration are managed with a type-II implanted system compared with a type-I system with an external pump.

Glossopharyngeal nerve block using ultrasound guidance: a case report of a new technique.

A new technique for blocking the glossopharyngeal nerve is described using ultrasound guidance. It is felt this technique will decrease the incidence of complications and increase the efficacy of this block for pain relief in cancer patients. The pertinent anatomic and technical considerations are discussed.

Comparison of bupivacaine and alkalinized bupivacaine in brachial plexus anesthesia.

To define the effect of alkalinization of bupivacaine 0.5% in subclavian perivascular brachial plexus blockade, the time to onset, time to peak effect, and 6-hour regression of sensory and motor blockade were determined. Sixty physical status ASA I and II patients were randomly allocated to one of two groups and a double-blind design was used: group I (n = 30) received bupivacaine 0.5% (pH, 5.5) 3 mg/kg, while group II (n = 30) received alkalinized bupivacaine 0.5% (pH, 7.05-7.15) 3 mg/kg. Onset and regression of sensory blockade were determined by pinprick in the C4-T2 skin dermatomes, while motor blockade was assessed using a scheme of proximal to distal muscle group paralysis. Time to onset of sensory blockade (group I, 4.0 +/- 1.2 min; group II, 3.6 +/- 0.9 min) and time to peak sensory effect (group I, 17.7 +/- 1.8 min; group II, 16.3 +/- 1.8 min) did not differ significantly between the groups. Similarly, no difference in time to onset of motor blockade (group I, 6.9 +/- 1.7 min; group II, 6.3 +/- 1.5 min) or time to peak motor effect (group I, 18.1 +/- 1.9 min; group II, 15.1 +/- 1.9 min) was observed. Regression of postoperative sensory and motor blockade was similar in both groups. It is concluded that alkalinization of bupivacaine 0.5% solutions does not confer any added clinical advantage in subclavian perivascular brachial plexus blockade when compared with commercially available bupivacaine.

Clonidine prolongs canine tetracaine spinal anaesthesia.

Using a randomized blind cross-over design, the comparative efficacy of clonidine in prolonging tetracaine spinal anaesthesia was studied in six mongrel dogs. Lumbar subarachnoid injections (1 ml) of: tetracaine 4 mg with clonidine 150 micrograms, tetracaine 4 mg with epinephrine 200 micrograms, tetracaine 4 mg, clonidine 150 micrograms, epinephrine 200 micrograms, and five per cent dextrose in H2O (vehicle) were administered randomly to each animal at 5-7 day intervals. Subarachnoid tetracaine produced a motor blockade of 186 +/- 58 (mean +/- SEM) min. Both clonidine and epinephrine produced a similar prolongation of tetracaine motor blockade, 135 per cent (p less than 0.01) and 116 per cent (p less than 0.05) respectively, compared with tetracaine alone. No motor blockade was observed in dogs receiving clonidine, epinephrine or five per cent dextrose in H2O. The addition of clonidine to tetracaine spinal anaesthesia produced a significant increase in duration of sensory blockade, 56 per cent (p less than 0.01) and 107 per cent (p less than 0.01) respectively, when compared to tetracaine with and without epinephrine. Subarachnoid clonidine alone produced a sensory blockade of 76 +/- 17 minutes, while only one animal receiving subarachnoid epinephrine had a sensory blockade (40 minutes). No neurologic deficits were observed in any of the animals. The study concludes that during spinal anaesthesia with tetracaine in dogs, clonidine is as effective as epinephrine in prolonging motor blockade, but is more effective in prolonging sensory blockade.

Pseudomonas aeruginosa colonisation in an intensive therapy unit: role of cross infection and host factors.

Despite the sparsity of Pseudomonas aeruginosa in the environment colonisation and infection with this organism was found at several sites by selective culture in 20 out of 46 patients in an intensive therapy unit. Three patients developed Ps aeruginosa pneumonia. Serial serogrouping and phage typing identified multiple strains in the unit and in the same patient. Rectal carriage occurred in 16 patients but rectal strains did not subsequently appear in tracheal aspirates; strains varied in their affinity for the upper respiratory tract. Colonisation was not directly related to length of stay and was detected in 16 of those colonised within 24 hours of admission. In intubated patients, who were colonised more frequently than those not intubated, upper respiratory tract colonisation correlated strongly with low initial arterial pH values. Personnel were probably responsible for cross infection among patients when the unit was busy. Strain differences and the susceptibility of patients also influenced colonisation and infection. Elimination of major reservoirs of Ps aeruginosa and compliance with procedures to control cross infection remain essential if patients in hospital are to escape colonisation by the organism.