Lumbar infusion test in normal pressure hydrocephalus.

OBJECTIVE: To compare potential clinical value of plateau pressure (P(pl)), resistance to outflow (R(out)), pulse-pressure amplitude (P(plA)) and rate of pressure increase (v(P)), taken from the constant rate lumbar infusion test (LIT), as predictors for the outcome of shunt surgery. METHODS: Recordings from preoperative LIT in 55 patients were scrutinized for the values of P(pl), P(plA), v(P) and R(out). Gait, memory, spatial capacity and reaction ability were tested before and 6 months after shunt surgery. RESULTS: Forty-three (78%) of the patients improved. There were no statistically significant differences in P(pl), R(out), P(plA) or v(P) between improved and not improved patients. Five patients with P(pl) below 22 mmHg (the cut off level) improved after shunting, while 16 and eight patients with R(out) below the cut off levels of 18 and 14 mmHg/ml/min improved. P(plA) correlated with P(pl) and R(out) (r = 0.74 and 0.63, respectively). In the group of patients with high P(plA) (>/=20 mmHg) as many as 93% improved but a high P(plA) did not recruit more improved patients than P(pl) or R(out) alone. CONCLUSION: v(P) or P(plA) does not add useful information to P(pl) for selecting patients with suspected NPH for surgery. R(out) calculations from LIT does not provide advantage over using the steady-state plateau pressure for selecting patients for surgery and may increase the risk of missing patients who should benefit from surgery.

Comparison between the lumbar infusion and CSF tap tests to predict outcome after shunt surgery in suspected normal pressure hydrocephalus.

OBJECTIVE: To compare the lumbar infusion test and the cerebrospinal fluid (CSF) tap test for predicting the outcome of shunt surgery in patients with suspected normal pressure hydrocephalus. METHODS: 68 patients with suspected normal pressure hydrocephalus were studied. The absence of preceding history indicated idiopathic disease in 75% of these. All patients were assessed twice with walking and psychometric tests before lumbar infusion test and tap test assessments. The lumbar infusion test was done using a constant infusion rate (0.80 ml/min) and regarded as positive if the steady state CSF plateau pressure reached levels of > 22 mm Hg (resistance to outflow > 14 mm Hg/ml/min). The tap test was regarded as positive if two or more of four different test items improved after CSF removal. As the variability in baseline test results was large, the better of two evaluations was used in comparisons with the results after CSF removal, as well as to evaluate the outcome after shunt surgery. Only patients with a positive lumbar infusion test or a positive tap test had surgery. RESULTS: The results of the CSF tap test and the lumbar infusion test agreed in only 45% of the patients. Of the total cohort, 47 (69%) had positive test results and were operated on; 45 (96%) of these reported subjective improvement, and postoperative assessments verified the improvements in 38 (81%). Improvements were highly significant in walking, memory, and reaction time tests (p < 0.001). Most of the patients improved by surgery (84%) were selected by a positive lumbar infusion test, and only 42% by a positive tap test. Positive predictive values were 80% for lumbar infusion test and 94% for tap test. The false negative predictions in the operated group were much higher (58%) with the tap test than with the lumbar infusion test (16%). CONCLUSIONS: Both the lumbar infusion test and the tap test can predict a positive outcome of shunt operations in unselected patients with suspected normal pressure hydrocephalus. The two tests are complementary and should be used together for optimal patient selection.

Severe traumatic brain lesions in Sweden. Part I: Aspects of management in non-neurosurgical clinics.

This paper reports a study of 587 consecutive patients treated for severe traumatic brain lesions (coma greater than 6 hours) during 1977-1984. Epidemiology, management and outcome were documented in 425 patients during the first part of the study (1977-1982) as a basis for future efforts at improvements. A total of 70-80 patients with severe head injuries were admitted annually to the Department of Neurosurgery in Lund and 88.6% of these patients were referred from 14 local hospitals, most of which are situated more than 50 km from Lund. Half of the patients were older than 40 years and 25% older than 60. Focal intracranial mass lesions were diagnosed in 64% of the patients. In the total study 41% of the patients were described as 'talk and deteriorate' and 13% as 'talk and die'. In 1983 a protocol for primary management was introduced in all local hospitals in the region. The management protocol caused a significant decrease (p less than or equal to 0.05) in the number of explorative craniotomies in local hospitals and a virtual disappearance of late surgical procedures (greater than 6 hours after injury). A fall was observed in the number of patients arriving at the Department of Neurosurgery with respiratory insufficiency. The study illustrates the epidemiology of severe head injuries in Sweden and the present state of management of these patients in non-neurosurgical departments. It is concluded that an overall outcome comparable to other reported series is also feasible in regions with a relatively sparse population and large geographical distances provided that strict recommendations for initial management are given to the local hospitals.

Severe traumatic brain lesions in Sweden. Part 2: Impact of aggressive neurosurgical intensive care.

During a 6 year period (1977-1982), 425 patients were treated in the Department of Neurosurgery, University Hospital of Lund, for severe traumatic brain lesions (coma greater than 6 hours). From 1983 a more aggressive management protocol was introduced including early recording of intracranial pressure (ICP) and 162 patients were included in the study 1983-1984. A dangerous increase in ICP in spite of adequate surgical treatment and moderately controlled hyperventilation was the incentive for barbiturate coma therapy in selected patients. In the first part of the study overall mortality was 48% whereas 39% of the patients reached good recovery/moderate disability 6 months after injury. During the second part of the study the corresponding figures were 35% and 54%, respectively (in both cases p less than or equal to 0.01). In the group of patients with focal intracranial mass lesions mortality decreased from 59% to 46% (p less than or equal to 0.05) and good recovery/moderate disability increased from 30% to 42% (p less than or equal to 0.05). Improvement in outcome was even more pronounced in patients with no-mass lesions, mortality decreased from 30% to 12% and good recovery/moderate disability increased from 56% to 80% (p less than or equal to 0.05 and p less than or equal to 0.01, respectively). No change occurred in age distribution or in the types of intracranial lesions that could explain these improvements. It is concluded that aggressive neurosurgical intensive care significantly improves outcome in patients with severe traumatic brain lesions.

Severe traumatic brain lesions in Sweden. Part 3: Economic aspects of aggressive neurosurgical intensive care.

The present study had two main objectives: Firstly, to document the economic differences between 'ordinary' and 'aggressive' neurosurgical intensive care and secondly, to evaluate the medical benefits in relation to costs for different subgroups of head-injured patients. The study compares patients injured in traffic accidents and treated in the Department of Neurosurgery, University Hospital of Lund, during 1977-1978 (n = 67) with similar patients treated during 1983-1984 (n = 87) after introduction of more vigorous neurosurgical intensive care. The economic analysis was performed by means of the CRISE-method (Cost Related Index Score Evaluation) and all costs were related to the monetary value in 1984. Adoption of a program for 'aggressive' neurosurgical intensive care increased the costs per treated patient by about 46% (from 70.887 Swedish Crowns (SEK) to 103.452 SEK). Mortality decreased significantly after the change in intensive care and the cost per surviving patient remained virtually unaffected (131.928 SEK vs. 132.357 SEK). Further, after introduction of the 'aggressive' programme a larger proportion of the economic expenditures were spent on patients who ultimately recovered well. It is concluded that the increase in costs following introduction of a more vigorous intensive care programme in patients with severe traumatic brain lesions is very reasonable in relation to the documented medical benefits.

Cerebral blood flow, vasoreactivity, and oxygen consumption during barbiturate therapy in severe traumatic brain lesions.

Mean hemispheric cerebral blood flow (CBF) and intracranial pressure (ICP) were measured in 19 severely head-injured patients treated with barbiturate coma. The CBF was calculated from the clearance of tracer substance monitored by extracranial scintillation detectors after intravenous administration of xenon-133. In 11 of the patients cerebral arteriovenous oxygen differences were measured simultaneously. In all patients the effects of pronounced hyperventilation were recorded prior to initiation of barbiturate treatment. A normal CBF response to hyperventilation (delta CBF/delta PaCO2 greater than or equal to 1) was obtained in eight patients. In these patients induction of barbiturate coma was accompanied by physiological decreases in CBF and in the calculated cerebral metabolic rate of oxygen (CMRO2); they also exhibited a rapid and lasting decrease in ICP. A decreased or an abolished CO2 reactivity was recorded (delta CBF/delta PaCO2 less than 1) in 11 patients. In 10 of these 11 patients the physiological decreases in CBF and CMRO2 were not obtained during barbiturate treatment and the decrease in ICP was transitory. This study demonstrates a correlation between cerebral vasoreactivity, physiological effects of barbiturate therapy, and clinical outcome.

Translabyrinthine acoustic neuroma surgery as performed by the otoneurosurgical group at Lund University Hospital.

The Lund otoneurosurgical group has operated 97 out of 118 pontine angle tumours using the translabyrinthine approach originally described by House. The pre- and postoperative evaluation of these 97 patients is described. The traditional classification of acoustic neuromas, the results of the reported surgery and complications are discussed.

Complications due to prolonged ventricular fluid pressure recording.

All complications in a consecutive series of 648 patients subjected to prolonged recording of the ventricular fluid pressure (VFP) during 1982-1986 were registered and analysed. The procedure did not cause permanent symptoms or deficits in any case except for one haemorrhagic complication. Definite infections caused by the VFP recording were found in 4.3% of the 540 patients (83%) surviving their disease or lesion, and in 1.9% in non-survivors. These infections were almost exclusively registered in patients treated with prolonged drainage of hemorrhagic ventricular fluid, while definite infections in other patients were found in only 1.3%. Most infections were caused by Staphylococcus epidermidis and all infections could be treated successfully. Infection did not cause or contribute to the lethal outcome in any case. In 60% of the cases with infectious complications laboratory signs of ventriculitis occurred after a surgical revision of the ventriculostomy. The duration of VFP recording was of subordinate importance for the development of infection. In 13 patients (1.9%) during the studied period a reliable VFP recording was not obtained, a fact that points to the need for alternative methods in a minority of patients with elevated intracranial pressure. It is concluded that complications caused by VFP recording can be kept at an acceptably low frequency in patients without haemorrhagic cerebrospinal fluid demanding long-term drainage.

A comparison of intraparenchymatous and intraventricular pressure recording in clinical practice.

A comparison of intraventricular pressure (IVP) and intraparenchymatous pressure was performed in 11 patients with severe traumatic brain lesions. Intraparenchymatous pressure was measured with a Honeywell microtransducer placed intracerebrally. Before the microtransducer was used in clinical practice, basic data on drift and temperature sensitivity were tested in experiments in vitro. Under clinical conditions the correspondence between the measured IVP and intraparenchymatous pressures appeared to be better than previously reported for different devices for epidural or subdural pressure recording. It is concluded that intraparenchymatous pressure monitoring is reliable in clinical practice and that such measurements are valuable in patients with compressed and/or distorted ventricles that preclude possibilities for IVP recording.

Bacterial contamination in cerebrospinal fluid shunt surgery.

Infection is a major complication of cerebrospinal fluid (CSF) shunt treatment with a reported incidence of 8-27%. In the present study, comprising 64 patients operated under strictly defined preoperative and peroperative hygienic measures and without use of prophylactic antibiotics, the infection rate was 3.1%. Out of the 2 cases of shunt infection recorded, 1 was probably caused by peroperative contamination and 1 by postoperative, hematogenous spread. Bacterial cultures from the operation area before incision and during operation were negative in 95% and 78%, respectively, and when positive yielded low numbers of organisms. Specimens taken after skin closure revealed growth in 59% and high bacterial numbers in 20%, mostly of Staphylococcus epidermidis and other resident skin bacteria. In addition, cultures of irrigation solutions, kept in open bowls during operation, yielded bacterial growth in 65% with a predominance of S. epidermidis. Thus, the strict hygienic measures did not prevent bacterial recolonization of the wound during operation. It is conceivable that endogenous as well as exogenous spread may be of importance in this context. The contamination of irrigation solutions indicates that closed irrigation systems should be used in this type of surgery.

Cerebral hemodynamics in patients with acute severe head trauma.

Mean hemispheric cerebral blood flow (CBF) was studied in 11 comatose brain-injured patients following intravenous administration of xenon-133. Repeated measurements were performed in order to evaluate cerebral vasoreactivity following a decrease in PaCO2. In addition, the effect of induced barbiturate coma was evaluated in patients with intracranial hypertension. The cerebral vasoreactivity and the CBF response following induction of barbiturate coma varied. In patients with normal CO2 reactivity, barbiturate treatment was accompanied by a considerable decrease in CBF as compared to patients with decreased or abolished CO2 response. During barbiturate treatment the intracranial pressure (ICP) became normal in three of four patients with preserved CO2 response, but reached normal levels in only one of five patients with impaired CO2 reactivity. Patients whose ICP became normal recovered. The data suggest a positive correlation between CO2 reactivity and the effect of barbiturate treatment. Furthermore, preserved cerebral vasoreactivity after severe head injury may be of prognostic value.

Postoperative CT findings in acoustic neurinomas operated upon by a translabyrinthine approach.

The findings at CT examinations, performed on 46 patients with acoustic neurinomas about 6 months after translabyrinthine surgery, were analyzed and compared with preoperative findings. Direct as well as indirect signs of expansion had disappeared postoperatively. Bulging of cerebellar tissue towards the operative defect in the petrous bone, a finding not connected with local adhesions, was notable. Hypodensity in the vicinity of the removed tumor occurred either due to local widening of the subarachnoid space or due to changes within the cerebellar parenchyma. Local and general widening of the fourth ventricle as a sign of atrophy was a frequent finding.

Subarachnoid hemorrhage of unknown origin: prognosis and prognostic factors.

The cases of 127 consecutive patients with subarachnoid hemorrhage (SAH), in whom cerebral panangiography revealed no cause for the bleeding nor any sign of an intraparenchymatous hemorrhage, were reviewed in a study of the long-term prognosis and the possible prognostic factors in this condition. Data for all 127 patients in the study were obtained, with an average follow-up period of 5.4 years. After the 1st week post-SAH, only three rebleeds had occurred. In all, 80% of the patients had returned to full activity, 91% to at least part-time work; if the patients with hypertension were excluded, these figures rose to 86% and 95%, respectively. Decreased wakefulness on admission related to a slightly poorer prognosis, whereas age and red blood cell count in the cerebrospinal fluid had no prognostic significance. Of those patients who, at the end of the 2nd week following the SAH, were fully awake and had not developed any symptoms of delayed cerebral ischemia (87% of all patients admitted), 88% returned to full activity, 97% to at least part-time work. The survival rate for this group, as well as causes of death, seem to be within the range for normal individuals. It should thus be possible to inform these patients (at least the normotensive ones) of the benignity of their condition, directly after normal angiography. Even among the patients who were able to return to full activity, symptoms attributable to the SAH were common: 22% experienced problems such as frequent headaches, vertigo, irritability, and increased fatigability.

Pain relief from peripheral conditioning stimulation in patients with chronic facial pain.

In a prospective study, 50 consecutive patients, referred to a pain treatment unit for surgery to alleviate various forms of facial pain, were all given transcutaneous nerve stimulation (TNS) therapy and followed for 2 years. Of the 44 patients remaining at the 2-year follow-up review, 20 (45%) reported satisfactory analgesia from conventional or acupuncture-like TNS. The latter technique markedly improved the overall results. No serious side effects were seen. Atypical facial pain of known etiology responded best to treatment, but satisfactory relief was often produced with tic douloureux. Duration of the pain condition as well as sex of the patient were predictors of treatment results. It is concluded that TNS therapy represents a valid alternative to surgery when pharmacological therapy fails, especially in the elderly and in patients with atypical facial pain.

Aerobic and anaerobic bacteria in neurosurgical infections. Per-operative culture with flexible contact agar film.

Fourteen of 80 patients (17.5 per cent) who underwent elective craniotomy preceded by a strict pre-operative routine of skin decontamination contracted postoperative wound infection. Most of the infections were probably from endogenous sources and from eight of the wounds low-virulent resident skin bacteria, Propionibacterium acnes and/or Staphylococcus epidermidis, were isolated. Since thorough pre-operative preparation of the skin did not reduce the incidence of infection to an acceptable level, antibiotic prophylaxis might be indicated in this type of surgery.

Early management of aneurysmal subarachnoid hemorrhage.

The Lund Clinic serves a population of 1.46 million inhabitants. During the calendar year 1981, 72 patients presented with a ruptured supratentorial aneurysm, diagnosed either at angiography or at autopsy. Upon admission, 60% of the patients were in good condition and 40% were in poor condition. Eighty-three per cent were admitted within 72 hours after the subarachnoid hemorrhage (SAH). In the total series, 50% made a good recovery; the overall management morbidity was 19% and the management mortality was 31%. Thirty-one patients in Grades I-III underwent early operation (43% of the total series), with a favorable outcome in 74% and 7% mortality. Of the 35 patients who were admitted early and in good condition, 71% made a good recovery, and the management mortality was 9%. These figures may be compared to the 51% favorable outcome and 27% mortality reported from the Cooperative Aneurysm Study with late operation. In the early operation cases, the incidence of significant arterial narrowing at postoperative angiography performed on Day 9 +/- 2 after SAH was 30% and the incidence of permanent neurological deficits of delayed onset was 10%. Two of the early operation patients developed permanent symptomatic hydrocephalus.