The bispectral index declines during neuromuscular block in fully awake persons

Bispectral index (BIS) is an electroencephalographic variable promoted for measuring depth of anesthesia. Electromyographic activity influences surface electroencephalography and the calculation of BIS. In this study, we sought to determine the effect of spontaneous electromyographic activity on BIS. BIS was monitored in three volunteers by using an Aspect A-1000 monitor. The experiment was repeated in one volunteer. Electromyographic activity was recorded. Alcuronium and succinylcholine were administered. No other drugs were used. In parallel with spontaneous electromyographic activity of the facial muscles, BIS decreased in response to muscle relaxation to a minimum value of 33 and, in the repeated measurement, to a minimum value of 9 when total neuromuscular block was achieved. In two volunteers, no total block was achieved. BIS decreased to a minimal value of 64 and 57, respectively. In turn, recovery of BIS coincided with the reappearance of spontaneous electromyographic activity. During the entire experiment, the volunteers had full consciousness. BIS, assessed by software Version 3.31, correlates with spontaneous electromyographic activity of the facial muscles. BIS failed to detect awareness in completely paralyzed subjects. Thus, in paralyzed patients, BIS monitoring may not reliably indicate a decline in sedation and imminent awareness.

IMPLICATIONS

The bispectral index (BIS) is an electroencephalographic variable intended for measuring depth of anesthesia. Electromyographic activity influences the calculation of BIS. We found that the administration of a muscle relaxant to unanesthetized volunteers decreases the bispectral index value. Thus, awareness in totally paralyzed patients cannot be excluded.

[Application of muscle relaxants for rapid-sequence induction of anaesthesia]

The present study evaluates the use of muscle relaxants for rapid-sequence induction (RSI) and different application techniques (pre-curarisation, priming, timing) as a part of a nationwide survey in Germany. In 86.8% of anaesthesia departments succinylcholine is used for RSI and an average of 56.5% of respondents used only succinylcholine for RSI. Of all non-depolarising muscle relaxants rocuronium is the most frequently used alternative. Of the anaesthesia departments 2.6% use rocuronium regularly in patients with increased risk for aspiration of stomach contents; level one centres significantly more than others, 12.9% answered that pre-curarisation techniques were never used, whereas 45.6% use non-depolarising neuromuscular blocking drugs before giving succinylcholine in 80-100% of cases. Priming is not used by 64.4% of respondents, as opposed to 9.8% who utilise this technique regularly. The statements regarding timing are 71.1% and 5.4%, respectively. Alcuronium is used for RSI in departments in which the financial aspect is the primary decision criteria. Despite ist known side-effects and the on-going discussion over the past years, succinylcholine is still the most frequently used muscle relaxants for RSI. Priming is often declined by anaesthetists in Germany, most probably due to the absence of clear advantages and the possibility of severe complications. It is the opinion of the authors that timing but also drugs with a slow onset (e.g., alcuronium and Pancuronium) are obsolete in the context of RSI.

[Neuromuscular blockade after atracurium and alcuronium with propofol and thiopental]

Does propofol or thiopentone enhance the effect of nondepolarizing muscle relaxants? We evaluated the effects of propofol and thiopentone on the pharmacodynamics of atracurium and alcuronium in 43 surgical patients (ASA I and II) under general anaesthesia.

METHODS

The patients were randomized into five groups, A-E. Anaesthesia was induced in all patients with fentanyl 4 micrograms/kg i.v. Patients in groups A and C patients received thiopentone 7 mg/kg i.v., and relaxation was achieved with alcuronium 0.25 mg/kg (group A) and atracurium 0.5 mg/kg (group C). Electromyography (train of four, TOF) was used to determine the time of onset of relaxation (AZ) and the maximum degree of blockade (T%). The recovery times to 25%, 50% and 75% of baseline muscle strength were recorded. Additionally, the TOF ratio T4:T1 was calculated, indicating the probable end of relaxation at a ratio of 0.7. At the beginning of the recovery phase (T1 = 15%) propofol 1% 3 mg/kg was given, and the effect on the TOF was measured. Patients in groups B and D patients received total intravenous anaesthesia (TIVA) with propofol 1% 6-12 mg/kg per hour continuously after induction with 3 mg/kg. The action profile of alcuronium 0.25 mg/kg (group B) and atracurium 0.5 mg/kg (group D) were recorded. Group E patients received thiopentone (10 mg/kg per hour) under the use of atracurium 0.5 mg/kg. Ventilation was performed with 30%/70% oxygen and N2O. The results were analyzed for significance using the Mann-Whitney U-test (P = 0.019).

RESULTS

A slight difference in AZ was noted for alcuronium under the use of TIVA between propofol and thiopentone: 13 min and 5 min, respectively. Otherwise, the pharmacodynamics (T% and recovery of neuromuscular function) of the two relaxants exhibited no major differences related to thiopentone, propofol or their combination. The TOF was not influenced under additional propofol application. Noteworthy were the wide distribution of the time course of action (up to 3 h) and the magnitude of T% depression under alcuronium.

CONCLUSION

Propofol and thiopentone have no potentiating influence on the time course of action and the magnitude of relaxation with alcuronium and atracurium. Pharmacodynamics of nondepolarizing muscle relaxants do not seem to be influenced by these two hypnotics.

Cerebral arterial blood flow velocity during induction of general anesthesia: rapid intravenous induction versus awake intubation

Changes in middle cerebral arterial flow velocity (MCAV) during rapid intravenous induction and awake intubation using transcranial Doppler sonography were investigated. The study involved 20 patients without disorders of the central nervous or cardiovascular systems who were scheduled for maxillofacial surgery. In the intravenous induction group, anesthesia was induced with sodium thiopental, and orotracheal or nasotracheal intubation was facilitated with succinylcholine chloride or alcuronium chloride. In the awake intubation group, orotracheal or nasotracheal intubation was performed under intravenous sedation with diazepam and topical anesthesia with 4% lidocaine. Arterial blood pressures, heart rate, and MCAV were monitored at specific intervals. During intravenous induction, blood pressures decreased after the administration of thiopental and muscle relaxants and increased during endotracheal intubation. MCAV was remarkably slowed after the administration of thiopental and during mask ventilation. During awake intubation, blood pressures were increased by endotracheal intubation. MCAV was decreased from the administration of diazepam to the transtracheal injection of lidocaine, but returned to the control value from endotracheal spray to endotracheal intubation. These results suggest that smooth awake intubation may be the safest method of induction for patients with cerebrovascular disorders.

Early tracheal intubation with thiopentone in elective surgery

We have studied tracheal intubating conditions within 30 s of administration of thiopentone in 24 patients and compared this with our usual method of tracheal intubation, which involves 3 min of manual ventilation in 29 patients. All patients received papaveretum 10 mg 3 min before induction and alcuronium at induction of anaesthesia. Satisfactory intubating conditions were observed in 83% of patients in both groups. There were no difficult or failed intubations and no patient had laryngospasm. The duration of laryngoscopy in the control group was 14.1 (SD 8.6) s (range 7-50 s), compared with 12.4 (3.1) s (range 6-20 s), in the early intubation group (ns). In the control group there was a significant decrease in systolic pressure before tracheal intubation and a significant increase in heart rate after intubation, compared with baseline values. The average systolic pressure in the early intubation group increased only minimally: from a pre-intubation value of 143.3 (21.2) mm Hg to 145.5 (25.1) mm Hg after intubation. Our results demonstrate that early tracheal intubation under thiopentone supplemented with an opioid and a non-depolarizing neuromuscular block is feasible, associated with minimal changes in arterial pressure and not accompanied by an increased incidence of side effects.

Determinants of the reversal time of competitive neuromuscular block by anticholinesterases

We have assessed, in 200 patients, the determinants of the reversal time of competitive neuromuscular block by anticholinesterase when alcuronium and atracurium neuromuscular block were antagonized by neostigmine 0.04 and 0.08 mg kg-1 and edrophonium 0.5 and 1.0 mg kg-1. A biexponential relationship was found between the reversal time (time from injection of anticholinesterase to a train-of-four ratio of 70%) and the degree of neuromuscular block at reversal (all groups; F ratio, P less than 0.05). Reversal time was determined by two processes: direct antagonism by the anticholinesterase and spontaneous recovery of the neuromuscular blocking agent, with the latter becoming the major determinant at profound levels of neuromuscular block (0-10% of control twitch height). Neostigmine, in the doses studied, appeared to have a higher "ceiling" of neuromuscular block which it completely antagonized, although edrophonium had a more rapid onset of action. The reversal time for alcuronium became progressively longer relative to atracurium as neuromuscular block increased because of the slower spontaneous recovery rate. Avoidance of profound neuromuscular block at the completion of surgery is required to ensure reliable antagonism of the block within 5-10 min by an anticholinesterase. Neostigmine 0.08 mg kg-1 was found to be the most effective agent in antagonizing profound neuromuscular block.

Comparison of trichloroethylene and enflurane as adjuncts to nitrous oxide and relaxant anaesthesia

Forty women who underwent gynaecological surgery were randomly allocated to receive trichloroethylene, enflurane, or enflurane plus fentanyl as adjuncts to nitrous oxide/relaxant anaesthesia with controlled ventilation. No serious cardiac dysrhythmias were seen in any group. Each patient was observed postoperatively for 4 hours by a nurse blind to the technique used, and questioned at 24 hours by a similarly blinded anaesthetist. Recovery after trichloroethylene was not significantly prolonged although postoperative analgesia by visual analogue was better, opiate analgesia was required less frequently and there was less nausea and vomiting than in either of the enflurane groups. We argue for the continued use of trichloroethylene by this technique, because it costs one hundred times less than enflurane and because of the potential morbidity of the postoperative opiate dosage required after enflurane.

Measurement of functional residual capacity by sulfur hexafluoride washout

Measurement of functional residual capacity (FRC) by the open-circuit multiple breath tracer gas washout technique is an established method. A system based upon washout of sulfur hexafluoride (SF6) during mechanical ventilation is described. The central unit in the system is a sensitive and rapid-response infrared SF6 analyzer. SF6 is washed in until the alveolar concentration of SF6 is 0.5%, a concentration so low that the supply of other gases is hardly influenced. During washout, the flow of SF6 from the lungs is calculated by a computer every 10 ms from signals representing expiratory flow and SF6 concentration. The total volume of SF6, washed out, is calculated by integration of SF6 flow. Since the alveolar concentration at the end of washin is known, the lung volume may be obtained. The measurement procedure is highly automated and the result is presented by the computer immediately after washout. Accurate and reproducible results in model lung tests were obtained during air and N2O/O2 ventilation. Comparison with body plethysmography (FRCBOX) in eight sitting healthy subjects gave the following: FRCSF6 = 7 ml + 0.98 X FRCBOX, r = 0.99. Comparison with nitrogen washout (FRCN2) in five postoperative patients gave the following: FRCSF6 = 59 ml + 0.97 X FRCN2, r = 0.97. FRCSF6 during N2O/O2 ventilation was the same as during air/O2 ventilation in a group of paralyzed patients. The measurement system has not been tested in patients with obstructive lung disease.

Clinical comparison of atracurium and alcuronium in gynaecological surgery

In a double-blind, prospective, randomised trial in 51 female patients, atracurium 0.6mg/kg provided acceptable intubating conditions more rapidly than did alcuronium 0.25 mg/kg. Atracurium produced more profound neuromuscular twitch suppression than alcuronium. The effect of atracurium was longer-lasting than that of alcuronium (32 minutes and 22 minutes respectively to achieve 10% recovery) and it took slightly longer to reverse with neostigmine. Seven patients in the atracurium group who underwent short surgical procedures required supplementary neostigmine to achieve adequate reversal. Two cases of sinus bradycardia were noted in the atracurium group, but hypotension was not a clinical problem in any patient. Atracurium appears to be a useful relaxant, but a smaller dose than that used here should be chosen for short procedures.

[A case of anaphylactoid reaction following administration of etomidate]

After injection of etomidate during surgery for herniation of an intervertebral disk an anaphylactoid reaction occurred. Generalized erythema, severe urticaria, and rise in heart rate and blood pressure drop were observed. After treatment with an antihistaminic and a corticosteroid the phenomenons completely disappeared within 45 minutes.

Failed intubation. A case report

A case report illustrates one of the dangers of intubation with use of a long-acting muscle relaxant where the clinical situation was misjudged. There is still a good case to be made out for the use of suxamethonium for intubation in a routine operating list to provide additional cover in the event of 'failed intubation'.

Effects of pancuronium and alcuronium on the changes in arterial pressure and plasma catecholamine concentrations during tracheal intubation

The changes in the plasma concentrations of noradrenaline, adrenaline and dopamine, during tracheal intubation, were studied in 17 patients. Nine patients received pancuronium and eight alcuronium to produce neuromuscular blockade. In the patients receiving pancuronium, intubation of the trachea was accompanied by an increase in mean arterial pressure, and in the plasma concentrations of noradrenaline and adrenaline. In the alcuronium group, there were no significant changes in the plasma concentrations of any catecholamine, nor any change in mean arterial pressure in response to intubation of the trachea.

Total intravenous anaesthesia by an intermittent technique. Use of methohexitone, ketamine and a muscle relaxant

Good quality anaesthesia with smooth recovery can be induced by methohexitone 40 mg, ketamine 100 mg, diazepam 5 mg and alcuronium 15-20 mg and maintained with methohexitone 30 mg and ketamine 10 mg at 5-minute intervals and controlled ventilation with 30% oxygen in air. The technique is economical in running and capital costs and may have special implications for avoiding atmospheric pollution, for use in developing countries, and in emergency situations.

Anaesthesia for patients undergoing prolonged reconstructive and microvascular plastic surgery

The anaesthesiological problems related to prolonged reconstructive plastic surgery in 22 patients were investigated in retrospect. Surgery consisted mainly of reconstructions, including microvascularization (7 emergency reimplantations, 15 plastic reconstructions), and the duration of the balanced anaesthesias varied between 5 h 10 min and 15 h 35 min. As the patients were relatively young and healthy, no serious cardiovascular complications occurred. Blood loss was intentionally replaced with dextran, in most instances, and in a group of 15 elective patients, mean haematocrit level decreased from 0.41 to 0.31 during surgery. In about half of the material, the central temperature was monitored; it remained within 35.8-38 degrees C. In the longest anaesthesia (15 h 35 min) the temperature stayed within 0.4 degrees C, the patient placed on a heating mattress. In 2 patients, transient paresis of the muscles of the hand, which was exposed and abducted for i.v. infusion and blood pressure recording, was observed. A questionnaire was sent to the patients and 19 of 20 responded. The predominant subjective complaint was nausea, while sensations following catheterization of the bladder were also a common untoward recollection. One patient developed laryngeal oedema after extubation and about a third experienced breathing difficulties on awakening from the anaesthesia. Postoperative pain appeared not to be a significant problem.

Morbidity after outpatient anaesthesia. A comparison of two techniques of endotracheal anaesthesia for dental surgery

A comparison was made of two anaesthetic techniques for outpatient dental surgery; the basis for comparison was symptomatic morbidity. One group of patients was managed with spontaneous breathing of nitrous oxide, oxygen and halothane; the other was ventilated mechanically, and received fentanyl and alcuronium. The latter anaesthetic was associated with a significantly higher incidence of morbidity on the day of operation, but not subsequently. The incidence of dysrhythmias was not significantly different. The comfort and safety of patients are discussed in relation to the choice of anaesthetic.

Total intravenous anaesthesia: a technique using flunitrazepam, ketamine, muscle relaxants and controlled ventilation of the lung

A potentially acceptable and uncomplicated technique of total intravenous anaesthesia is described using flunitrazepam for induction, and maintenance by ketamine infusion with neuromuscular blockade and controlled ventilation using oxygen-enriched room air. A significant complication was the 23% incidence of nausea and/or vomiting encountered in the fifty-six patients studied. Definite factual recall of the surgical experience was reported by one patient. This was attributable to an accidental error in technique. Postoperative drowsiness was also a feature of the technique. The usual cardiovascular and psychomimetic effects associated with ketamine administration appeared markedly attenuated by flunitrazepam induction. Fifty-three (96.3%) patients expressed their willingness to receive the same anaesthetic again. Further experience of total intravenous anaesthesia with the introduction of cerebral function monitoring, allowing correlation of depth of anaesthesia with drug dosage, should allow further refinement of the technique to ensure successful and acceptable anaesthesia.

[A comparative study on the effect of halothan-N2O-anaesthesia and neuroleptanalgesia on plasma catecholamines during the intra- and postoperative period (author's transl)]

The influence of neuroleptanalgesia and halothane-N2O-anaesthesia on the activity of the sympathetic nervous system was studied continuously in the intra- and postoperative period in 2 groups of 10 patients undergoing abdominal operations. In the neuroleptanalgesia-group the noradrenaline level in plasma rose continuously during the course of the operation and this increase was highly significant. The adrenaline level in plasma increased as well, however this increase did not depend on the duration of the operation. In the halothane-N2O-group only a small increase of both adrenaline and noradrenaline in plasma could be demonstrated intraoperatively. One hour after the end of the operation the plasma levels of adrenaline and noradrenaline were elevated in both groups. The noradrenaline level was even higher after neuroleptanalgesia. Four hours after the end of surgery the levels of adrenaline and noradrenaline started to decrease, but were still above the preanaesthetic level. The increase of the concentration of catecholamines in plasma indicating an activation of the sympathetic nervous system was not associated with a corresponding increase in heart rate and blood pressure intra- as well as postoperatively in either group. Only in the neuroleptanalgesia-group was there a small, but insignificant increase of the systolic and diastolic pressure postoperatively.

Comparison of domperidone, droperidol, and metoclopramide in the prevention and treatment of nausea and vomiting after balanced general anesthesia

Women (185) undergoing elective orthopedic surgery under balanced general anesthesia were given 5 or 10 mg of domperidone, 1.25 mg of droperidol, 10 mg of metoclopramide, or a saline placebo intravenously in a double-blind random fashion 5 minutes before the end of anesthesia to prevent postoperative vomiting. Administration of the same antiemetic was repeated intramuscularly during the first 24 hours postoperatively if the patient complained of nausea or retched or vomited. Sigificantly (p less than 0.05 to p less than 0.001), fewer of the patients given droperidol were nauseated (25%) or vomited (17%) in comparison with patients given saline (incidence of nausea was 55% and vomiting 40%). Incidences of nausea and vomiting were similar in patients given domperidone, metoclopramide, or saline. Furthermore, 39 to 45% of the patients given domperidone, metoclopramide, or saline needed additional doses of the same drug, whereas only 22% of the patient given droperidol required a second dose. It is concluded that droperidol is effective in the prevention and treatment of postoperative nausea and vomiting after balanced general anesthesia but that domperidone or metoclopramide are not.

[Behaviour of plasma-cortisol during ophthalmological operations in patients under electrostimulation anaesthesia (author's transl)]

Plasma cortisol was determined before, during and after ophthalmological operations. These were performed under electrostimulation anaesthesia using adhesive electrodes attached to the dermatome of the site of operation. Plasma cortisol decreased after premedication and induction of anaesthesia; it increased continuously during surgery beyond the end of operation. Thirty minutes after extubation plasma cortisol decreased again.

[Plasma-catecholamines under electrostimulation and neurolept anaesthesia for retina and vitreous body operations (author's transl)]

We determined in two groups of patients with normal circulation and metabolism during operations on the retina and vitreous body the concentration of plasma catecholamines. The intensity of stress was compared between electrostimulation anaesthesia and neuroleptanaesthesia. Venous blood was sampled 1) before premedication, 2) 30' after premedication, 3) at the start of surgery, 4) 45' after the start of surgery, 5) 30' after extubation. Plasma catecholamines (adrenaline and noradrenaline) were determined using a modified trihydroxyindol-spectrofluoremetric method (combined "Batch-technique"). There was no relevant difference between the two techniques of anaesthesia when using the concentrations of plasmacatecholamines as an indicator of stress resulting from operation and anaesthesia.

[The circulatory system in patients under electrostimulation anaesthesia during ophthalmological operations (author's transl)]

Anaesthesia by electrostimulation and its effects on the circulatory system were investigated in 65 elderly patients, in whom operations on the retina and vitreous body were performed. Stimulation of the dermatomes of the first and second trigeminal nerve as well as of C3 and C4 was performed using stimulating needles in 25 patients and adhesive electrodes in 40 patients. All patients were intubated after injection of thiopentone and a muscle relaxant. Anaesthesia was maintained by continuous electrostimulation, intermittent relaxation and normoventilation with N2O/O2 in a ratio of 1/1. During this anaesthesia technique, marked stability of the circulatory system was observed. This was noted in 32 normotensive and 33 hypertensive patients, the latter being partly under antihypertensive medication. Electrostimulation anaesthesia therefore may be recommended for elderly and high risk patients.

General anaesthesia with intravenous flunitrazepam, continuous ketamine infusion and muscle relaxant. A preliminary report

We present a preliminary report of an anaesthetic technique for abdominal surgery involving a combination of flunitrazepam induction and continuous ketamine maintenance of anaesthesia, specifically avoiding the use of any inhalational agents. Standard techniques of muscle relaxation, intubation and ventilation with oxygen-enriched air were employed.

Hemodynamic effects of locally applied epinephrine used with various general anesthetic techniques

Halothane-nitrous oxide-oxygen (GOF), nitrous oxide-oxygen with diallyl-nor-toxiferine (Jackson-Rees method), or nitrous oxide-oxygen with droperidol-pentazocine (modified NLA) were administered in 190 instances of repair of cleft lips and cleft palates. Epinephrine, 1:30,000, 1:100,000, or 1:300,000, was injected as the vasoconstrictor around the operative field. Epinephrine concentration of 1:100,000 provided sufficient hemostasis, whereas 1:300,000 was insufficient. With the same concentration of epinephrine, GOF and modified NLA seemed to be better than the Jackson-Rees method, since the GOF and modified NLA groups showed less increase of pulse rate, blood pressure, and plethysmographic changes. A 1:30,000 concentration of epinephrine could be used safely with the Jackson-Rees method and the hemostasis with this concentration was superior to 1:100,000. However, it is recommended only for the cleft lip operation, since these patients are younger and need better hemostasis, and hypersalivation after reversal does not disturb the postoperative course. So-called epinephrine-induced arrhythmia with halothane anesthesia occurred in 1 of 34 instances with 1:300,000 solution and in 5 of 48 instances with 1:100,000 solution. Propranolol was given in only one instance. All others returned to normal rhythm with hyperventilation with pure oxygen. The use of 1:100,000 solution of epinephrine as an adjunct with modified NLA is the most satisfactory and safe method for cleft palate operations, and 1:30,000 with the Jackson-Rees is the better method for cleft lip repairs.

Respiration, circulation and anaesthetic management in obesity. Investigation before and after jejunoileal bypass

Some ventilatory and circulatory parameters were studied in 17 very obese patients before and after weight reduction following jejunoileal bypass. A low vital capacity and signs of impaired lung function with intrapulmonary shunting, increased alveolar-arterial Po2 difference and low Pao2 were found. Although the spirometric values improved significantly after weight reduction, the ventilatory disturbance persisted. A normal response to inhalation of CO2 was seen. The total blood volume was high and did not change after weight reduction. However, if calculated as blood volume per kg body weight, the values were lower than normal, and they increased as a consequence of weight reduction. Cardiac output was slightly lower than normal in relation to oxygen consumption. Total peripheral resistance was normal. Arterial blood pressure, which was in the high normal range preoperatively, decreased significantly after weight reduction. Total doses of intravenous anaesthetic agents and muscle relaxants were the same as for patients of normal weight. The importance of preoperative evaluation and of respiratory care of obese patients undergoing elective surgery is stressed.

Rapid intubation with fazadinium. A comparison of fazadinium with suxamethonium and alcuronium

The speed of onset and intubation conditions have been compared for suxamethonium 1 mg/kg, alcuronium 0-32 mg/kg and fazadinium 1 mg/kg and 1-25 mg/kg. Fazadinium 1 mg/kg was not significantly different in times to intubation from suxamethonium although the latter gave a highly significant greater number of patients with excellent conditions. The higher dose of 1-25 mg/kg fazadinium did not give significantly better intubating conditions than the lower dose. Although the times to intubation for the two dose levels of fazadinium did not differ statistically, the higher dose was significantly slower in onset than suxamethonium. Alcuronium was slower than either suxamethonium or fazadinium 1 mg/kg in producing satisfactory conditions. The nondepolarizing drug, fazadinium, may be a useful neuromuscular blocking agent in emergency cases where rapid intubation is required and when it is wished to avoid possible or probable adverse effects from the depolarising drug suxamethonium.

Techniques, indications and results of intraoperative radiotherapy of advanced cancers

After removing resectable lesions at operation, residual cancer nests were sterilized by irradiation before surgical closure. The great advantage of intraoperative radiotherapy lies in the treatment of lesions such as gastric cancers located near radiosensitive organs, and radioresistant tumors, such as soft-tissue sarcoma. Since the lesion is exposed directly to irradiation, a cancerocidal dose can be delivered without affecting normal structures. Clinical results have shown that cure can be expected following excision of the primary mass.