Outcome of Severe Traumatic Brain Injury at KSMC: Functional Outcomes of ICP Monitor Insertion-Two Years' Experience.

PURPOSE: To evaluate functional outcomes of severe traumatic brain injuries after insertion of intracranial pressure (ICP) monitor at King Saud Medical City (KSMC) and their correlation to each other. PATIENTS AND METHODS: A retrospective observational study for all adult patients (age >18 years) who were diagnosed with severe head injury and underwent ICP insertion at KSMC. Patients diagnosed between 2017 and 2019 were included. Data for measured outcomes, Glasgow outcome scale (GOS), Karnofsky Performance Score (KPS) and length of stay (LOS) and prognostic factors, data like: age, gender and primary Glasgow coma score (GCS) was obtained from patients' files and direct communication with patients or their caregivers. We also compared patients who underwent ICP monitoring alone with those who underwent ICP with decompressive craniectomy (DC). Follow-up period ranged from 6-24 months. RESULTS: Seventy-four patients were included in this cohort study. Outcome measurements for patients with decompression and ICP were lower than those with ICP alone. KPS and GOS showed strong correlation (p<0.01) in whole cohort and in both subgroups (ICP alone and ICP with DC). KPS showed significant correlation with length of stay (p=0.026). CONCLUSION: ICP monitoring is valid tool in management of severely head injured patients. Patients who underwent DC had a worse outcome. KPS can be used as alternative tool to measure functional outcome in severe traumatic brain injury.

Different Visual Weighting due to Fast or Slow Vestibular Deafferentation: Before and after Schwannoma Surgery.

Background: Feedback postural control depends upon information from somatosensation, vision, and the vestibular system that are weighted depending on their relative importance within the central nervous system. Following loss of any sensory component, the weighting changes, e.g., when suffering a vestibular loss, the most common notion is that patients become more dependent on visual cues for maintaining postural control. Dizziness and disequilibrium are common after surgery in schwannoma patients, which could be due to interpretation of the remaining sensory systems involved in feedback-dependent postural control and spatial orientation. Objective: To compare visual dependency in spatial orientation and postural control in patients suffering from unilateral vestibular loss within different time frames. Methods: Patients scheduled for schwannoma surgery: group 1 (n = 27) with no vestibular function prior to surgery (lost through years), group 2 (n = 12) with remaining vestibular function at the time of surgery (fast deafferentation), and group 3 (n = 18) with remaining function that was lost through gentamicin installations in the middle ear (slow deafferentation). All patients performed vibratory posturography and rod and frame investigation before surgery and 6 months after surgery. Results: Postural control improved after surgery in patients that suffered a slow deafferentation (groups 1 and 3) (p < 0.001). Patients that suffered fast loss of remaining vestibular function (group 2) became less visual field dependent after surgery (p ≤ 0.035) and were less able to maintain stability compared with group 1 (p = 0.010) and group 3 (p = 0.010). Conclusions: The nature and time course of vestibular deafferentation influence the weighting of remaining sensory systems in order to maintain postural control and spatial orientation.

Improved lumbar infusion test analysis for normal pressure hydrocephalus diagnosis.

OBJECTIVES: Constant infusion lumbar infusion test (LIT) is an important way to find which patients, of those with signs and symptoms corresponding to normal pressure hydrocephalus (NPH) who will improve from shunt operation. LIT is a stress test on the ability for cerebrospinal fluid re-absorbtion. The aim of this study is to show how the information from LIT can be improved by quantitative analysis and avoidance of methodological pitfalls. MATERIAL AND METHODS: The potential pitfalls, and the analysis method, are described in detail. The analysis was applied on pre-operative constant infusion LIT from 31 patients operated for NPH, with known outcome. The pre- and post-operative walking speed was used to grade pathology progression or improvement. RESULTS: The maximal, plateau, intra-spinal pressure at constant infusion LIT is an ambivalent indicator for NPH: while low maximal pressure indicates no cerebrospinal fluid (CSF) absorbtion pathology, too high pressure (≥47 mmHg) may mean no diagnosis, because of stenosis of the Sylvian aqueduct. When subjects with too high intra-spinal pressure were excluded, the new analysis gave a couple of diagnostic volume parameters, of which one appears to be an optimal LIT parameter for identifying NPH patients with 14% better accuracy than plateau pressure. CONCLUSION: By avoiding methodological pitfalls, and optimal analysis of the results from lumbar infusion test, the number of NPH patients who do not have a successful outcome after shunt operation may be further decreased.

Improved Outcomes following the Establishment of a Neurocritical Care Unit in Saudi Arabia.

BACKGROUND: Dedicated neurocritical care units have dramatically improved the management and outcome following brain injury worldwide. AIM: This is the first study in the Middle East to evaluate the clinical impact of a neurocritical care unit (NCCU) launched within the diverse clinical setting of a polyvalent intensive care unit (ICU). DESIGN AND METHODS: A retrospective before and after cohort study comparing the outcomes of neurologically injured patients. Group one met criteria for NCCU admission but were admitted to the general ICU as the NCCU was not yet operational (group 1). Group two were subsequently admitted thereafter to the NCCU once it had opened (group 2). The primary outcome was all-cause ICU and hospital mortality. Secondary outcomes were ICU length of stay (LOS), predictors of ICU and hospital discharge, ICU discharge Glasgow Coma Scale (GCS), frequency of tracheostomies, ICP monitoring, and operative interventions. RESULTS: Admission to NCCU was a significant predictor of increased hospital discharge with an odds ratio of 2.3 (95% CI: 1.3-4.1; p=0.005). Group 2 (n = 208 patients) compared to Group 1 (n = 364 patients) had a significantly lower ICU LOS (15 versus 21.4 days). Group 2 also had lower ICU and hospital mortality rates (5.3% versus 10.2% and 9.1% versus 19.5%, respectively; all p < 0.05). Group 2 patients had higher discharge GCS and underwent fewer tracheostomies but more interventional procedures (all p < 0.05). CONCLUSION: Admission to NCCU, within a polyvalent Middle Eastern ICU, was associated with significantly decreased mortality and increased hospital discharge.

Perioperative serum cortisol levels in ACTH sufficient and ACTH deficient patients during transsphenoidal surgery of pituitary adenoma.

PURPOSE: No previous study has analyzed serum cortisol levels during transsphenoidal endoscopic pituitary surgery in patients with and without hydrocortisone (HC) substitution. METHODS: A total of 15 patients undergoing surgery for a pituitary adenoma were studied. Those with normal ACTH function were either not given HC (n = 7) or received 50 mg intravenous HC at the start of surgery (n = 4). Patients with ACTH deficiency received intravenous HC of 100 mg in the morning before surgery (n = 4) with the additional 50 mg for an afternoon operation (n = 2). Propofol and remifentanil were used as anesthetics. Serum cortisol was measured at the start of and every 30 min during surgery. RESULTS: Among 7 patients with normal ACTH function without HC substitution, cortisol levels before surgery were 126-244 nmol/L, among the 4 patients undergoing surgery in the morning, whereas the 3 who underwent surgery in the afternoon had lower levels, 38-76 nmol/L. During nose/sinus surgery cortisol levels decreased to 79-139 and 24-54 nmol/L, respectively. At intrasellar manipulation a distinct rise was noted. Also, in the 4 ACTH sufficient patients receiving HC, cortisol levels decreased during nose/sinus surgery, but only with a slight increase during intrasellar surgery. In the 4 ACTH deficient patients cortisol peaked at 1914-2582 nmol/L. CONCLUSIONS: Patients with normal ACTH function without HC substitution had very low cortisol levels during the first part of surgery, likely suppressed by the anesthetics. After mechanical impact in the sella, a marked increase in cortisol was noted. Supraphysiological cortisol levels were achieved with our routine HC substitution, advising us to reduce the supplementation.

PREHAB vs. REHAB - presurgical treatment in vestibular schwannoma surgery enhances recovery of postural control better than postoperative rehabilitation: Retrospective case series.

OBJECT: To evaluate post-surgical postural stability when treating patients with remaining vestibular function with intratympanic gentamicin (PREHAB) prior to schwannoma surgery. METHOD: 44 consecutive patients with some form remaining vestibular function scheduled for vestibular schwannoma surgery. 20 were medically deafferented with intratympanic gentamicin before surgery and 24 were not. Both groups were of the same age, had the same tumor size, same type of surgery, and same perioperative sensory rehabilitation (training exercises), and no surgical complications. Postural stability measured as energy expenditure while standing on a force platform during vibratory stimulation of the calf muscles, performed prior to surgery (or gentamicin treatment) and 6 months after surgery. RESULTS: Patients pretreated with gentamicin had significantly better postural stability at the time for follow-up (p < 0.05) and displayed a better adaptive capacity when faced with a postural challenge (p < 0.01). They were also able to use vision more efficiently to control their stability (p < 0.05). CONCLUSIONS: By separating the sensory loss (through intratympanic gentamicin, that ablates the remaining vestibular function) from the intracranial surgical trauma, the postural control system benefited from a better short-term (adaptation) and long-term (habituation) recovery, when experiencing a postural challenge or resolving a sensory conflict. The benefits could be attributed to; active and continuous motor learning as the vestibular function slowly attenuates; no concomitant central nervous dysfunction due to effects from neurosurgery, thus allowing time for a separate unimpeded recovery process with more limited challenges and objectives; and the initiation and certain progression of sensory reweighting processes allowed prior to surgery. In contrast, worse compensation could be due to; immobilization from nausea after surgery, harmful amount of stress and cognitive dysfunction from the combination of surgical and sensory trauma and an abrupt vestibular deafferentation and its consequences on sensory reweighting.

Quality of Life and Work Capacity Are Unrelated to Approach or Complications After Pituitary Surgery.

OBJECTIVE: Endoscopic pituitary surgery has shown favorable clinical outcomes. Less is known about the impact of surgical approaches on health-related quality of life (HRQoL) and work capacity. The present study was undertaken to compare transsphenoidal microscope-assisted surgery with endoscopic transsphenoidal surgery regarding preoperative and surgical factors for the final outcome of HRQoL and work capacity. METHODS: In a retrospective study of patients operated on for pituitary adenoma, outcome was compared between those operated on before and after transition with endoscopic surgery at our department. Data were gathered via patient questionnaires and patients' files. RESULTS: After exclusions, 235 patients were included (99 microsurgical and 136 endoscopic). Frequency of complications was similar but tumor size was significantly larger in the endoscopic group. Complications did not affect HRQoL or work capacity. HRQoL was not affected by surgical technique but showed an overall trend toward lower values compared with the general population. Sick leave, return to work frequency, and permanent sick leave were not affected by surgical technique. Female gender was a factor for lower ratings in all outcome variables. CONCLUSIONS: Surgical technique does not influence HRQoL or work capacity in this long-term follow-up although both are decreased compared with the general population. We conclude that fully endoscopic pituitary surgery, despite including larger tumors, bears the same risk for complications as microsurgery. In addition, females have a greater risk for decrease in HRQoL and work ability. This factor should be taken into account when informing patients and appreciating expectations of treatment.

Vascular risk factors in INPH: A prospective case-control study (the INPH-CRasH study).

OBJECTIVE: To assess the complete vascular risk factor (VRF) profile of idiopathic normal pressure hydrocephalus (INPH) using a large sample of representative patients with INPH and population-based controls to determine the extent to which vascular disease influences INPH pathophysiology. METHODS: All patients with INPH who underwent shunting in Sweden in 2008-2010 were compared to age- and sex-matched population-based controls. Inclusion criteria were age 60-85 years and no dementia. The 10 most important VRFs and cerebrovascular and peripheral vascular disease were prospectively assessed using blood samples, clinical examinations, and standardized questionnaires. Assessed VRFs were hypertension, hyperlipidemia, diabetes, obesity, psychosocial factors, smoking habits, diet, alcohol intake, cardiac disease, and physical activity. RESULTS: In total, 176 patients with INPH and 368 controls participated. Multivariable logistic regression analysis indicated that hyperlipidemia (odds ratio [OR] 2.380; 95% confidence interval [CI] 1.434-3.950), diabetes (OR 2.169; 95% CI 1.195-3.938), obesity (OR 5.428; 95% CI 2.502-11.772), and psychosocial factors (OR 5.343; 95% CI 3.219-8.868) were independently associated with INPH. Hypertension, physical inactivity, and cerebrovascular and peripheral vascular disease were also overrepresented in INPH. Moderate alcohol intake and physical activity were overrepresented among the controls. The population-attributable risk percentage was 24%. CONCLUSIONS: Our findings confirm that patients with INPH have more VRFs and lack the protective factors present in the general population. Almost 25% of cases of INPH may be explained by VRFs. This suggests that INPH may be a subtype of vascular dementia. Targeted interventions against modifiable VRFs are likely to have beneficial effects on INPH.

Incidence and outcome of surgery for adult hydrocephalus patients in Sweden.

OBJECT: To present population-based and age related incidence of surgery and clinical outcome for adult patients operated for hydrocephalus, registered in the Swedish Hydrocephalus Quality Registry (SHQR). METHODS: All patients registered in SHQR during 2004-2011 were included. Data on age, gender, type of hydrocephalus and type of surgery were extracted as well as three months outcome for patients with idiopathic normal pressure hydrocephalus (iNPH). RESULTS: The material consisted of 2360 patients, 1229 men and 1131 women, age 63.8 ± 14.4 years (mean ± standard deviation (SD)). The mean total incidence of surgery was 5.1 ± 0.9 surgeries/100,000/year; 4.7 ± 0.9 shunt surgeries and 0.4 ± 0.1 endoscopic third ventriculostomies. For iNPH, secondary communicating hydrocephalus and obstructive hydrocephalus, the incidence of surgery was 2.2 ± 0.8, 1.9 ± 0.3 and 0.8 ± 0.1/100,000/year, respectively. During 2004-2011, the incidence of surgery increased in total (p = .044), especially in age groups 70-79 years and ≥80 years (p = .012 and p = .031). After surgery, 253 of 652 iNPH patients (38.8%) improved at least one step on the modified Rankin scale (mRS). Number needed to treat was 3.0 for improving one patient from unfavourable (mRS 3-5) to favourable (mRS 0-2). The mean score of a modified iNPH scale increased from 54 ± 23 preoperatively to 63 ± 25 postoperatively (p < .0001, n = 704), and 58% improved. No significant regional differences in incidence, surgical techniques or outcome were found. CONCLUSIONS: Incidence of hydrocephalus surgery increased significantly during 2004-2011, specifically in elderly patients. Surgical treatment of iNPH markedly improved functional independence, but the improvement rate was low compared to recent single- and multicentre studies. Thus, the potential for surgical improvement is likely lower than generally reported when treating patients as part of everyday clinical care.

Hearing and Vestibular Function After Preoperative Intratympanic Gentamicin Therapy for Vestibular Schwanomma as Part of Vestibular Prehab.

OBJECTIVE: To evaluate auditory and vestibular function after presurgical treatment with gentamicin in schwannoma patients. BACKGROUND: The vestibular PREHAB protocol aims at diminishing the remaining vestibular function before vestibular schwannoma surgery, to ensure less acute symptoms from surgery, and initiate a more efficient vestibular rehabilitation already before surgery. However, the potential cochleotoxicity of gentamicin is a concern, since modern schwannoma surgery strives to preserve hearing. STUDY DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: Seventeen patients diagnosed with vestibular schwannoma between 2004 and 2011, and took part in vestibular PREHAB program. The patients were of age 21 to 66 years (mean 48.8), 9 females and 8 males. INTERVENTION: Intratympanic gentamicin installations before surgery as part of the vestibular PREHAB. MAIN OUTCOME MEASURES: Hearing thresholds, word recognition score, caloric response, subjective visual vertical and horizontal, cVEMP, and vestibular impulse tests. RESULTS: Combined analysis of frequency and hearing threshold showed a significant decrease after gentamicin therapy (p < 0.001). Pure-tone average decreased with 7.1 ± 8.5 dB (p = 0.004), and speech recognition with 10%. The treatment resulted in unilateral vestibular deafferentation with no notable reaction to bithermal caloric irrigation (reduction 64%, p < 0.001), loss of the vestibulo-ocular response measured by the head-impulse test, and deviation of subjective horizontal/vertical to the side of the lesion (+2.2 degrees, p = 0.010). CONCLUSIONS: Intratympanic installations of gentamicin, as part of the vestibular PREHAB, result in unilateral vestibular deafferentation, but constitute a definite risk for high-frequency hearing loss. The hearing results are in line with those reported upon when treating Menière's disease.

A Patient-Assessed Morbidity to Evaluate Outcome in Surgically Treated Vestibular Schwannomas.

OBJECTIVE: Outcome after treatment of vestibular schwannomas can be evaluated by health providers as mortality, recurrence, performance, and morbidity. Because mortality and recurrence are rare events, evaluation has to focus on performance and morbidity. The latter has mostly been reported by health providers. In the present study, we validate 2 new scales for patient-assessed performance and morbidity in comparison with different outcome tools, such as quality of life (QOL) (European Quality of Life-5 dimensions [EQ-5D]), facial nerve score, and work capacity. METHODS: There were 167 total patients in a retrospective (n = 90) and prospective (n = 50) cohort of surgically treated vestibular schwannomas. A new patient-assessed morbidity score (paMS), a patient-assessed Karnofsky score (paKPS), the patient-assessed QOL (EQ-5D) score, work capacity, and the House-Brackmann facial nerve score were used as outcome measures. Analysis of paMS components and their relation to other outcomes was done as uni- and multivariate analysis. RESULTS: All outcome instruments, except EQ-5D and paKPS, showed a significant decrease postoperatively. Only the facial nerve score (House-Brackmann facial nerve score) differed significantly between the retrospective and prospective cohorts. Out of the 16 components of the paMS, hearing dysfunction, tear dysfunction, balance dysfunction, and eye irritation were most often reported. Both paMS and EQ-5D correlated significantly with work capacity. CONCLUSIONS: Standard QOL and performance instruments may not be sufficiently sensitive or specific to measure outcome at the cohort level after surgical treatment of vestibular schwannomas. A morbidity score may yield more detailed information on symptoms that can be relevant for rehabilitation and occupational training after surgery.

Age, gender and tumour size predict work capacity after surgical treatment of vestibular schwannomas.

AIMS: The aim of the present study was to identify predictive factors for outcome after surgery of vestibular schwannomas. DESIGN: This is a retrospective study with partially collected prospective data of patients who were surgically treated for vestibular schwannomas at a single institution from 1979 to 2000. Patients with recurrent tumours, NF2 and those incapable of answering questionnaires were excluded from the study. The short form 36 (SF36) questionnaire and a specific questionnaire regarding neurological status, work status and independent life (IL) status were sent to all eligible patients. PATIENTS AND METHODS: The questionnaires were sent to 430 eligible patients (out of 537) and 395 (93%) responded. Scores for work capacity (WC) and IL were compared with SF36 scores as outcome estimates. Patients were divided into two groups (<64, ≥64-years-old) in order to assess them for either WC or IL. Putative preoperative and postoperative predictive factors were tested in univariate and multivariable regression analysis for the outcome scores of WC, IL and SF36. RESULTS: In the group <64 years, age, gender and tumour diameter were independent predictive factors for postoperative WC in multivariate analysis. A high-risk group was identified in women with age >50 years and tumour diameter >25 mm. In patients ≥64, gender and tumour diameter were significant predictive factors for IL in univariate analysis. Perioperative and postoperative objective factors as length of surgery, blood loss and complications did not predict outcome in the multivariable analysis for any age group. Patients' assessment of change in balance function was the only neurological factor that showed significance both in univariate and multivariable analysis in both age cohorts. While SF36 scores were lower in surgically treated patients in relation to normograms for the general population, they did not correlate significantly to WC and IL. CONCLUSIONS: The SF36 questionnaire did not correlate to outcome measures as WC and IL in patients undergoing surgery for vestibular schwannomas. Women and patients above 50 years with larger tumours have a high risk for reduced WC after surgical treatment. These results question the validity of quality of life scores in assessment of outcome after surgery of benign skullbase lesions.

Vestibular "PREHAB".

A sudden unilateral loss or impairment of vestibular function causes vertigo, dizziness, and impaired postural function. In most occasions, everyday activities supported or not by vestibular rehabilitation programs will promote a compensation and the symptoms subside. As the compensatory process requires sensory input, matching performed motor activity, both motor learning of exercises and matching to sensory input are required. If there is a simultaneous cerebellar lesion caused by the tumor or the surgery of the posterior cranial fossa, there may be a risk of a combined vestibulocerebellar lesion, with reduced compensatory abilities and with prolonged or sometimes permanent disability. On the other hand, a slow gradual loss of unilateral function occurring as the subject continues well-learned everyday activities may go without any prominent symptoms. A pretreatment plan was therefore implemented before planned vestibular lesions, that is, "PREHAB." This was first done in subjects undergoing gentamicin treatment for morbus Ménière. Subjects would perform vestibular exercises for 14 days before the first gentamicin installation, and then continue doing so until free of symptoms. Most subjects would only experience slight dizziness while losing vestibular function. The approach--which is reported here--was then expanded to patients with pontine-angle tumors requiring surgery, but with remaining vestibular function to ease postoperative symptoms and reduce risk of combined cerebellovestibular lesions. Twelve patients were treated with PREHAB and had gentamicin installations transtympanically. In all cases there was a caloric loss, loss of VOR in head impulse tests, and impaired subjective vertical and horizontal. Spontaneous, positional nystagmus, subjective symptoms, and postural function were normalized before surgery and postoperative recovery was swift. Pretreatment training with vestibular exercises continued during the successive loss of vestibular function during gentamicin treatment, and pre-op gentamicin ablation of vestibular function offers a possibility to reduce malaise and speed up recovery.

Preoperative vestibular ablation with gentamicin and vestibular 'prehab' enhance postoperative recovery after surgery for pontine angle tumours--first report.

CONCLUSIONS: Preoperative gentamicin in combination with vestibular 'prehab' offers a possibility to reduce postoperative malaise and speed up recovery and may be used for patients undergoing such surgery when there is remaining vestibular function. OBJECTIVES: Removal of pontine angle tumours in a patient with remaining vestibular function causes symptoms of acute vestibular loss. A simultaneous cerebellar lesion can cause a combined vestibule-cerebellar lesion. PATIENTS AND METHODS: Twelve patients with pontine angle tumours but with near normal vestibular function were treated with intratympanic gentamicin in combination with vestibular 'prehab' to achieve preoperative vestibular ablation and compensation. After work-up patients started with a home-based vestibular training programme for 14 days. They then received a total of 1.2 ml of 30 mg/ml buffered gentamicin in four intratympanic installations over 2 days. They continued training and returned 6-16 weeks later. All patients were tested with calorics, vestibular video-impulse testing of all six canals, VEMP, subjective visual vertical and horizontal, posturography and pure tone and speech audiometry. RESULTS: There was a loss of caloric reactions and loss of impulses. In two patients the hearing deteriorated and in one hearing improved. All subjects were vestibulary compensated before surgery and no patient complained of dizziness or vertigo after surgery.

Long-term outcome in patients with suspected normal pressure hydrocephalus.

OBJECTIVE: To evaluate the outcome of patients with suspected normal pressure hydrocephalus at 6 months and 5 years after shunt surgery. METHODS: Seventy-five patients (mean age, 72.5 6 9 yr), with normal pressure hydrocephalus symptoms were included. Fifty-four patients with positive lumbar infusion and/or cerebrospinal fluid tap tests received a cerebrospinal fluid shunt, whereas 21 patients with negative test results did not undergo operation. Walk, reaction time, memory, and identical forms tests were used as baseline (before surgery) tests and were repeated at short- (6.1 6 4.6 mo) and long-term (5.5 6 1.4 yr) follow-up evaluations. Activities of daily life functions were assessed using the Barthel index. RESULTS: At the 6-month follow-up examination, 83% of the operated patients improved in gait, 65% improved in reaction time, 46% improved in memory, and 31% improved in identical forms tests; 96% found themselves subjectively improved. Because of unrelated mortality (37%) and declining general health from comorbidity, only 27 patients were available for the 5-year follow-up evaluation. Twenty-three of these patients had been treated with a shunt and had a remaining improvement in close to 40% in gait and reaction time, whereas fewer than 10% had an improvement in cognitive tests. Fifty-six percent reported subjective improvement compared with preoperative findings. More patients (64%) improved if younger than 75 years; for patients older than 75 years, only 11% of the patients improved. The Barthel index was higher (P < 0.05) in improved patients. CONCLUSION: Patients with normal pressure hydrocephalus benefit from shunt surgery for at least 5 years. High mortality rate, comorbidity, and old age hamper good long-term outcome and emphasize the importance of patient selection.

Is aqueductal stroke volume, measured with cine phase-contrast magnetic resonance imaging scans useful in predicting outcome of shunt surgery in suspected normal pressure hydrocephalus?

OBJECTIVE: To evaluate clinical usefulness of cerebrospinal fluid stroke volume (SV) assessed in the cerebral aqueduct, via cine phase-contrast magnetic resonance imaging, for predicting outcome after shunt surgery in suspected normal pressure hydrocephalus. METHODS: Thirty-eight patients with suspected normal pressure hydrocephalus were included. SV was assessed using cine phase-contrast magnetic resonance imaging, and the results were kept blinded until postoperative follow-up after 7 +/- 5.8 months (mean +/- standard deviation). Selection to surgery was based on a positive lumbar infusion test or cerebrospinal fluid tap test, and outcome was evaluated with objective tests. RESULTS: Six patients were excluded from SV measurements because of technical difficulties. Eight patients were not operated (negative lumbar infusion test and cerebrospinal fluid tap test). SV in the not operated patients (mean, 66 +/- 53 microl) did not differ from the operated patients (95 +/- 78 microl; P = 0.335). Operated patients showed statistically significant improvements in walk (P = 0.020), reaction time (P = 0.006), and memory (P = 0.001) tests. Patients were divided into three groups according to SV range: low (0-50 microl), middle (51-100 microl), and high (>100 microl). No statistically significant (P > 0.05) improvements in any of the objective tests were found in any of the SV ranges. The numbers of individually improved patients were similar in the different SV ranges: six out of seven in the low, nine out of nine in the middle, and five out of eight in the high range. Weak correlations were found between SV and the initial pulse amplitude (Rs = 0.043; P = 0.014) as well as the plateau pulse amplitude (Rs = 0.043; P = 0.014) as measured with the lumbar infusion test. CONCLUSION: The data from this study show no evidence that cine phase-contrast magnetic resonance imaging measurements of SV in the cerebral aqueduct are useful for selecting patients with normal pressure hydrocephalus symptoms to shunt surgery.