Babar Kahlon

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.

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?

OBJECTIVETo 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. METHODSThirty-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. RESULTSSix 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 μl) did not differ from the operated patients (95 ± 78 μl; 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 μl), middle (51–100 μl), and high (>100 μl). 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. CONCLUSIONThe 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.

Long-term outcome in patients with suspected normal pressure hydrocephalus

OBJECTIVETo evaluate the outcome of patients with suspected normal pressure hydrocephalus at 6 months and 5 years after shunt surgery. METHODSSeventy-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. RESULTSAt 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. CONCLUSIONPatients 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.

Vestibular PREHAB and gentamicin before schwannoma surgery may improve long-term postural function

Background: Unilateral vestibular deafferentation (uVD), as performed in vestibular schwannoma surgery, results in a chronic vestibular deficit, though most of the insufficiency can be compensated by other sensory input. By vestibular training (prehabituation) performed before surgery, motor adaptation processes can be instigated before the actual lesion. The adaptation processes of the altered sensory input could be affected if the vestibular ablation and surgery were separated in time, by pretreating patients who have remaining vestibular function with gentamicin. Objective: To determine whether presurgical deafferentation would affect postsurgery postural control also in a long-term perspective (6 months). Method: 41 patients subjected to trans-labyrinthine schwannoma surgery were divided into four groups depending on the vestibular activity before surgery (with no clinical significant remaining function n = 17; with remaining function n = 8), whether signs of central lesions were present (n = 10), and if patients with remaining vestibular activity were treated with gentamicin with the aim to produce uVD before surgery (n = 6). The vibratory posturography recordings before surgery and at the follow-up 6 months after surgery were compared. Results: The subjects pretreated with gentamicin had significantly less postural sway at the follow-up, both compared with the preoperative recordings and compared with the other groups. Conclusion: The results indicate that by both careful sensory training and separating the surgical trauma and the effects of uVD in time, adaptive processes can develop more efficiently to resolve sensory conflicts, resulting in a reduction of symptoms not only directly after surgery but also perhaps up to 6 months afterwards.

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.

Lumbar infusion test in normal pressure hydrocephalus.

Objective –  To compare potential clinical value of plateau pressure (Ppl), resistance to outflow (Rout), pulse‐pressure amplitude (PplA) and rate of pressure increase (vP), taken from the constant rate lumbar infusion test (LIT), as predictors for the outcome of shunt surgery.

Tumefactive demyelinating disease treated with decompressive craniectomy.

Background:  Tumefactive demyelinating disease (TDD) is a rare primary demyelinating disease with diagnostic and therapeutic challenges.

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

Abstract 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.

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.