CLINICAL ARTICLE J Neurosurg 128:250–257, 2018

Does subjective improvement in adults with intracranial arachnoid justify surgical treatment?

Katrin Rabiei, MD, PhD,1,2 Per Hellström, PhD,1 Mats Högfeldt-Johansson, MD,1,2 and Magnus Tisell, MD, PhD1,2

1Institute of Neuroscience and Physiology, Sahlgrenska Academy; and 2Department of , Sahlgrenska University Hospital, Gothenburg, Sweden

OBJECTIVE Subjective improvement of patients who have undergone for intracranial arachnoid cysts has justi- fied surgical treatment. The current study aimed to evaluate the outcome of surgical treatment for arachnoid cysts using standardized interviews and assessments of neuropsychological function and balance. The relationship between arach- noid location, postoperative improvement, and arachnoid cyst volume was also examined. METHODS The authors performed a prospective, population-based study. One hundred nine patients underwent neu- rological, neuropsychological, and physiotherapeutic examinations. The arachnoid cysts were considered symptomatic in 75 patients, 53 of whom agreed to undergo surgery. In 32 patients, results of the differential diagnosis revealed that the symptoms were due to a different underlying condition and were unrelated to an arachnoid cyst. Neuropsychological testing included target reaction time, Grooved Pegboard, Rey Auditory Verbal Learning, Rey Osterrieth complex figure, and Stroop tests. Balance tests included the extended Falls Efficacy Scale, Romberg, and sharpened Romberg with open and closed eyes. The tests were repeated 5 months postoperatively. Cyst volume was pre- and postoperatively measured using OsiriX software. RESULTS Patients who underwent surgery did not have results on balance and neuropsychological tests that were dif- ferent from patients who declined or had symptoms unrelated to the arachnoid cyst. Patients with a temporal arachnoid cyst performed within the normal range on the neuropsychological tests. Seventy-seven percent of the patients who underwent surgery reported improvement, yet there were no differences in test results before and after surgery. Arach- noid cysts in the temporal region and posterior fossa did not influence the preoperative results of neuropsychological and motor tests. The arachnoid cyst volume decreased postoperatively (p < 0.0001), but there was no relationship between volume reduction and clinical improvement. CONCLUSIONS The results of this study speak against objectively verifiable improvement following surgical treatment in adults with intracranial arachnoid cysts. https://thejns.org/doi/abs/10.3171/2016.9.JNS161139 KEY WORDS intracranial arachnoid cysts; neuropsychological testing; balance testing; cyst volume

rachnoid cysts are benign, fluid-filled malforma- ment are among the most common symptoms associated tions of the arachnoid tissue.20 Intracranial arach- with an arachnoid cyst.1 However, these symptoms are noid cysts have a prevalence of around 2%, and frequently encountered in the general population and are mostA are found incidentally.19 Individuals with arachnoid subjective and difficult to validate. Hence, the causal link cysts may be asymptomatic or present with a wide range between them and an arachnoid cyst is often uncertain or of neurological symptoms and signs.1 Symptoms related dubious. The indication for surgical treatment is therefore to arachnoid cysts are either secondary to hydrocepha- challenging in the case of the most common symptoms lus or due to compression of the adjacent neural tissue.1,27 associated with arachnoid cysts.1,19 , dizziness or imbalance, and cognitive impair- The aim of this study was to evaluate the clinical effect

ABBREVIATIONS FES(S) = Falls Efficacy Scale, Swedish version; MMSE = Mini–Mental State Examination; RAVLT = Rey Auditory Verbal Learning Test; ROCF = Rey- Osterrieth complex figure. SUBMITTED May 4, 2016. ACCEPTED September 28, 2016. INCLUDE WHEN CITING Published online February 17, 2017; DOI: 10.3171/2016.9.JNS161139.

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Unauthenticated | Downloaded 09/25/21 05:26 AM UTC Can subjective improvement justify surgery for arachnoid cysts? of surgical fenestration of intracranial arachnoid cysts. In patients were excluded at this point, based on nascent vas- addition to the patients’ reported symptoms, cognitive and cular and Parkinson’s dementia, leaving 107 pa- balance impairment were tested before and after surgery. tients in the study (mean age 47.3 years, SD 16.2 years, Furthermore, we aimed to examine, using volumetrics, range 18–76 years). Seventy-five patients were considered whether postoperative improvement and radiological re- symptomatic and were offered surgical treatment, of whom duction in cyst volume were related. 53 consented and 22 declined (Fig. 1). In 32 patients, the symptoms were found to be unrelated to the arachnoid cyst and were caused by a different underlying condition (e.g., Methods tension or ). Patient characteristics and Patient Population test results are presented in Table 1. All adults who had de novo cysts and were from the The surgical method of choice was fenestration per- western region of Sweden were prospectively and con- formed under general anesthesia. Patients who had under- secutively included in this study between December 2004 gone surgery were evaluated using the same test battery and December 2009. During this time, 125 patients (57 and by the same research team following the same proto- females and 68 males) between 18 and 83 years old (mean cols 5 months postoperatively. The treating neurosurgeons age 43 years) were included. The reasons for the initial were not part of the evaluation team. All new and residual imaging studies obtained in these patients were headache, symptoms and the patients’ reported outcome of surgery dizziness or imbalance, trauma, visual disturbance, sei- were noted by a neurologist who did not take part in the zures, cognitive impairment, and focal neurological signs patient’s surgical treatment. MRI was repeated 5 months (Supplemental eTable 1). and 1 year postoperatively. Patients who declined surgery Evaluations of images and referrals were performed by underwent follow-up by visiting the neurosurgical outpa- 2 senior neurosurgeons. All images were also reviewed by tient clinic. a neuroradiologist. One patient had an epidermoid cyst, and another patient was found to have a mega cisterna Neuropsychological Testing magna; both patients were excluded. Fourteen patients The same neuropsychologist (P.H.) examined all pa- were excluded from further investigation due to the com- tients. A clinical interview including medical history, bination of a lack of symptoms and a small cyst, leaving educational and occupational background, and patient 109 patients for further evaluation (Fig. 1). symptoms preceded the neuropsychological testing. The The study was approved by the Ethics Committee for psychometric tests performed were 1) target reaction time, Medical Research at Gothenburg University, and all pa- 2) Grooved Pegboard test performed with the dominant tients gave their written consent to participate in the study. and nondominant hand (Lafayette Instrumentation Co.), 3) the Rey Auditory Verbal Learning Test (RAVLT), 4) Clinical Examination the Rey-Osterrieth complex figure (ROCF), and 5) the One hundred nine patients were admitted for evalua- Swedish Stroop test.12,16,23,30 These tests measure different tion in the Research Unit at Sahlgrenska aspects of memory and recall: verbal learning and recall University Hospital. The evaluations included MRI and (RAVLT), visuospatial learning and recall (ROCF), at- neurological, neuropsychological, and physiotherapeutic tention and cognitive control (Stroop test and target reac- examinations and were all based on predetermined fixed tion time), and manual dexterity (Grooved Pegboard test). protocols. In addition to medical history and routine neu- These tests involve the function of many brain structures, rological examination, previous head trauma, hospital ad- including the region, anterior cingulate, the missions, and complications during birth and trauma in dorsolateral prefrontal cortex, and the head of the left cau- early childhood and later in life were recorded. The neuro- date.9,17,24 For neuropsychological tests, T-values based on logical examinations included the Mini–Mental State Ex- the subject’s age and sex were calculated (Table 1). amination (MMSE), the Bingley visual memory test, and the identical forms test.5,6,31 If headache was present, ex- Balance Testing tensive headache anamnesis was part of the fixed protocol. An experienced physiotherapist conducted the same At least 2 senior consultant neurologists were involved in standardized tests in all patients. The examination started the evaluation of the patients. Only patients with headache with an interview about the patient’s symptoms. The bal- classified by the International Headache Society’s ICHD-2 ance tests performed were the expanded version of the (International Classification of Headache Disorders, 2nd Falls Efficacy Scale, Swedish version [FES(S)]; the Rom- edition) as “headache attributed to nonvascular intracra- berg test; and the sharpened Romberg test with open and nial disorder” or “headache related to space-occupying closed eyes.11 The tests were performed twice, and the best lesion” were considered to have arachnoid cyst–related test value was noted. headache.10 A fixed protocol was used for the MRI examinations of all patients with arachnoid cysts, including FLAIR-, dif- Cyst Volume Measurement fusion-, and T1-weighted sequences, to allow both a dif- The cyst volume was measured preoperatively and 5 ferential diagnosis and volumetric measurements. months and 1 year postoperatively using FLAIR sequenc- After the examinations, each case was discussed at a es of 1.5-T MR images and OsiriX software version 6.5. multidisciplinary conference, and patients whose symp- The region of interest was manually outlined on each MRI toms had no other explanation were offered surgery. Two slice and was calculated by the software.25

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TABLE 1. Patient demographics and neuropsychological and balance testing Surgically Treated Patients Declined Surgery Patients w/ Symptoms Unrelated to AC Variable (n = 53) (n = 22) (n = 32) p Value Age in yrs 46.5 (16.8) 48.9 (17.5) 47.4 (14.8) NS Sex (F/M) 30/23 9/13 12/20 History of trauma 15/56 (27%) 6/22 (27%) 9/32 (28%) NS Cyst vol in ml 49.5 (52.4) 44 (36.7) 18 (20.8) NS*; 0.005† MMSE 27.6 (2.3) 28.6 (2.0) 30.0 (1.6) NS Bingley test 7.2 (1.91) 7.3 (1.65) 7.8 (1.88) NS Identical forms test 28.5 (11.7) 29.0 (11.6) 35.5 (14.4) NS*; 0.027† RAVLT 42.2 (13) 42.4 (13) 46.4 (13) NS RAVLT, delayed recall 45 (13) 45 (12) 50 (13) NS ROCF test (range)‡ >40 (28 to >40) >40 (28 to >40) >40 (28 to >40) NS Grooved Pegboard test Dominant hand 41.2 (23.0) 36.4 (20.5) 49.8 (18.2) NS*; 0.012†§ Nondominant hand 42.1 (19.2) 23.5 (39.9) 47.6 (14.5) 0.007*; NS† Target reaction time 49.0 (14.2) 41.4 (14.7) 49.7 (12.1) NS Swedish Stroop test 49.1 (10.7) 52.1 (9.4) 54.0 (12.0) NS Romberg test 53.4 (16.9) 56.5 (12.3) 54.7 (15.9) NS Sharpened Romberg Eyes open 49.1 (20.2) 49.6 (17.5) 49.0 (21.6) NS Eyes closed 21.1 (21.4) 22.8 (21.2) 22.9 (22.6) NS FES(S) score 5.49 (0.66) 5.44 (0.51) 5.22 (1.30) NS Cyst location Temporal 16 14 16 Frontal 9 2 4 Parietal 3 0 1 Occipital 5 0 1 Posterior fossa 13 4 9 Suprasellar 1 0 0 Intraventricular 1 1 0 Perimesencephalic 1 0 1 Ambient cistern 1 0 0 Multilobular 4¶ 1** 0 AC = arachnoid cyst; NS = not significant. For continuous variables, means (SD) are presented unless indicated otherwise. Neuropsychological test scores are T-values. For all tests the scores were compared between surgically treated patients and patients who declined surgery and those whose symptoms were due to other causes. Also, patients who declined surgery and those whose symptoms were due to other causes were compared. Only statistically significant values are presented. * Difference between surgically treated patients and those who declined surgery. † Difference between surgically treated patients and those whose symptoms were unrelated to an arachnoid cyst. ‡ The norms for the initial trial on the ROCF are presented in terms of cutoff values where “>40” means that the patient’s performance is less than 1 SD from the mean of healthy individuals and thereby considered normal. The exact T-values are not presented due to a heavily negatively skewed distribution in the normative sample. § Patients whose symptoms were due to other causes performed significantly worse than patients who underwent surgery later and those who declined surgery. ¶ One frontotemporal, 1 frontotemporoparietal, and 2 temporoparietal. ** Temporoparietal.

Statistical Analysis variables. All tests were 2-tailed; p < 0.05 was considered The chi-square test was used for nonordered categori- significant. The data were analyzed using version 9.4 of the cal variables, Fisher’s exact test for dichotomous variables, SAS System for Windows (SAS Institute). and the Mann-Whitney U-test for continuous variables. For comparison over time, the Wilcoxon signed-rank test was used for continuous variables and the sign test for categori- Results cal variables. For comparisons between 3 groups, the Man- Overall, the patients exhibited a wide range of symp- tel-Haenszel chi-square test was used for ordered categori- toms, including headache (60%), dizziness and/or imbal- cal variables and the Kruskal-Wallis test for continuous ance (42%), cognitive impairment (17%), (9%),

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FIG. 1. Flowchart showing the patient population. AC = arachnoid cyst. visual disturbance (7%), and focal neurological symptoms lobe region (1 case). One patient with persistent CSF leak- (6.5%) (Table 2). The reported frequency of head trauma age (who initially underwent surgery in the posterior fossa) was the same in all 3 groups (27%–28%). underwent reoperation with endoscopic third ventriculos- Headache was as prevalent in patients who opted for tomy and, later on, ventriculoperitoneal shunting. surgical treatment as in patients with symptoms unrelat- The permanent complications consisted of a venous in- ed to the arachnoid cyst (p = 0.96), but less prevalent in farction in combination with intracerebral fol- those who declined surgical treatment (p = 0.007). The lowing ligation of frontal bridging veins, which resulted frequency of the other symptoms did not differ between in complete damage to the right frontal lobe. The second the 3 patient groups (Table 2). patient developed epileptic seizures following a subdural empyema that was surgically evacuated with removal of the bone flap and reoperation with cranioplasty. Surgically Treated Patients At the 5-month follow-up, 41 (77%) patients described Of the 53 patients who underwent surgical treatment, their overall symptoms as improved, 8 (15%) considered 50 underwent open microsurgical fenestration and 3 un- their symptoms to be unchanged, and 2 (4%) were worse. derwent endoscopic fenestration. Shunting was performed One patient was lost to follow-up and another did not an- after the procedure in 4 patients because of concomitant swer this question. However, when comparing the number hydrocephalus. of symptoms before and after surgery, only 23 (43%) pa- Eleven patients (21%) suffered 15 complications, of tients were found to have complete remission of at least 1 which 13 were transient and 2 caused permanent sequelae preoperative symptom, while 26 (49%) were unchanged (3.8%). Six additional surgical procedures were performed and 3 (6%) had more symptoms than before surgery. Pa- to treat the different complications. tients reported improvement of headache and dizziness The transient complications consisted of epidural hema- but not of cognitive symptoms (Table 3). toma (1 case), (2 cases), subdural hy- No arachnoid cyst location could be associated with groma (2 cases), CSF leakage (3 cases), (1 case), patient-reported improvement. Furthermore, no arachnoid occipital neuralgia (1 case), pseudomeningocele (1 case), cyst location could be associated with improvement de- and transient aphasia related to edema in the left temporal fined as remission of at least 1 clinical symptom. Neither

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TABLE 2. Major complaints among all patients TABLE 4. Neuropsychological and balance test results before and after surgery in surgically treated patients No. of Patients (%) Surgically Patients w/ Variable Preop Value Postop Value p Value Treated Declined Symptoms Cyst vol in ml 49.5 (52.4) 31.0 (50.9) <0.0001 Patients Surgery Unrelated to Total RAVLT, total 42.2 (13) 42.7 (12) 0.93 Variable (n = 53) (n = 22) AC (n = 32) (n = 107) RAVLT, delayed recall 45.8 (13) 45.8 (13) 1.00 Headache 36 (68) 7 (32)* 21 (66) 64 (60) Grooved Pegboard test Dizziness or imbal- 23 (43) 11 (50) 11 (34) 45 (42) Dominant hand 41.2 (23.0) 38.1 (22.9) 0.56 ance Nondominant hand 42.1 (19.2) 34.2 (27.0) 0.29 Cognitive impairment 11 (20) 4 (18) 3 (9) 18 (17) Target reaction time 49.0 (14.2) 45.4 (12.5) 0.048 Visual disturbance 5 (9) 0 (0) 2 (6) 7 (7) Swedish Stroop test 47.1 (10.7) 49.1 (12.4) 0.80 Seizures 6 (11) 3 (14) 1 (3) 10 (9) ROCF (range)* >40 (28 to >40) >40 (28 to >40) 0.63 Focal neurological 4 (7) 1 (5) 2 (6) 7 (7) Romberg 53.4 (16.9) 53.8 (16.4) 0.83 symptoms Sharpened Romberg Other symptoms 6 (11) 0 2 (6) 8 (7.5) Eyes open 49.1 (20.2) 43.2 (24.0) 0.41 No subjective symp- NA 0 2 (6) 3 (3) toms Eyes closed 21.1 (21.4) 25.2 (24.3) 0.51 FES(S) 5.49 (0.66) 5.48 (0.80) 0.74 NA = not applicable. * Headache was less prevalent in patients who declined surgery (p = 0.007) Mean values (SD) are presented unless indicated otherwise. The mean values than in those who opted for surgery and those in whom the symptoms were are T-values. For comparison between groups, the Mann-Whitney U-test was considered to be due to other causes. used for continuous variables. * The norms for the initial trial on the ROCF are presented in terms of cutoff values where “>40” means that the patient’s performance is less than 1 SD from the mean of healthy individuals and thereby considered normal. The ex- headache nor dizziness was associated with a particular act T-values are not presented due to a heavily negatively skewed distribution arachnoid cyst location. in the normative sample. Neuropsychological Testing Balance Testing The neuropsychological test results of the surgically treated patients were similar to those of patients who de- The results of the balance tests were similar between clined or had symptoms unrelated to the arachnoid cyst. the patients who underwent surgery and those who de- Overall, the test results were within the reference range clined surgery or had symptoms unrelated to their arach- for all groups (Table 1). Following surgery, the patients noid cyst (Table 1). The patients who underwent surgery did not improve on any of the test variables except perhaps did not improve on any of the test parameters (Table 4). target reaction time (p = 0.048) (Table 4). Furthermore, Furthermore, the results of the balance tests did not dif- there were no differences in the test results of patients fer between those with posterior fossa arachnoid cysts and who reported cognitive impairment and those who did those with arachnoid cysts in other locations. A temporal not. Additionally, patients with temporal arachnoid cysts location was not found to affect the results of the balance performed within the normal range of neuropsychological tests. tests, and their test results were similar to those of patients Patients reporting dizziness/imbalance preoperatively with arachnoid cyst in other locations. exhibited worse results on the Romberg test (p = 0.004) and the sharpened Romberg tests with the eyes open (p = 0.012) and closed (p = 0.0081), but not on FES(S) (p = TABLE 3. Major complaints among surgically treated patients 0.085), compared with those who did not experience this before and after surgery symptom. These patients did not improve on any of the performed tests postoperatively. Preoperatively, patients No. of Patients (%) with posterior fossa arachnoid cysts performed similarly Preop Symptom Postop Symptom p on the balance tests to patients with an arachnoid cyst in Variable (n = 53) (n = 52) Value other locations. However, postoperatively, they performed Headache 36 (68) 19 (37) 0.0003 worse than patients with an arachnoid cyst in other loca- tions on the Romberg test (p = 0.0003) and the sharpened Dizziness or imbalance 23 (43) 10 (19) 0.005 Romberg test with the eyes open (p = 0.015) but not with Cognitive impairment 11 (20) 10 (19) NS the eyes closed (p = 0.17), and FES(S) (p = 0.51). The dif- Visual disturbance 5 (9) 2 (4) NS ference between preoperative and postoperative values Seizures 6 (11) 2 (4) NS within the group of patients with posterior fossa cysts Focal neurological 4 (7) 1 (2) NS was statistically significant only for the Romberg test (p symptoms = 0.050). Other symptoms 6 (11) 9 (17) NS Cyst Volume Measurements No subjective symptoms NA 8 (15) 0.02 The mean preoperative cyst volume in surgically

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Unauthenticated | Downloaded 09/25/21 05:26 AM UTC Can subjective improvement justify surgery for arachnoid cysts? treated patients was 49 ml (SD 52.4 ml, median 30 ml). ascribed to it in the general population.19 The increased At follow-up, this volume was reduced to 31 ml (SD 50.9 use of medical imaging in the assessment of patients re- ml, median 11 ml) (p < 0.0001). The cyst volume further porting multifactorial and prevalent symptoms has led to decreased to 29 ml (SD 49.4 ml, median 9 ml) at the 1-year an increase in the number of identified arachnoid cysts. radiological follow-up (p = 0.0005). Clinical improvement In such cases, clinical evaluation is challenging and com- was not related to a reduction in cyst volume (p = 0.71). plex.22,26,28,29 In fact, although most neurosurgeons agree that surgery should be reserved for symptomatic patients, arachnoid cyst size has been shown to be the most impor- Patients Who Declined Surgery and Patients With 3 Symptoms Unrelated to the Arachnoid Cyst tant predictor of surgical treatment. Headache, the most common symptom in arachnoid Of the 22 patients who declined surgery, 11 (50%) re- cyst, is also one of the most common and disabling condi- ported spontaneous improvement in their presenting symp- tions of humankind.8,15 In our study, headache was the most toms within 3 months and did not desire further follow-up. frequently reported symptom in the group of patients who Eight patients’ conditions improved over the following year. underwent surgery, whereas it was less prevalent among The remaining 3 patients eventually underwent surgery. those who declined surgery. The headache was improved in a significant number of our patients (47% of those who Neuropsychological Testing and Balance Testing complained of headache preoperatively did not suffer from There were no differences in performance on the Rom- headache at follow-up). This beneficial effect may be due to berg test, sharpened Romberg tests with the eyes open and our multidisciplinary approach to patient evaluation, with closed, FES(S), target reaction time, RAVLT, ROCF, and the involvement of experienced neurologists and a phys- Swedish Stroop test between the patients who declined iotherapist (evaluation of exertion headache). However, we surgery and those who underwent surgery and patients cannot rule out the placebo effect of surgery on symptom with symptoms unrelated to arachnoid cyst. Patients who improvement during this relatively short-term follow-up.7 declined surgery performed better than patients who un- Dizziness or imbalance, the second most common derwent surgery on the Grooved Pegboard test performed symptom in arachnoid cyst, is yet another complex and with the dominant hand. At the same time, patients who multifactorial condition.14,32,33 Our patients reported a high were not offered surgery performed worse than the other rate of improvement regarding this symptom postopera- groups on the same test (Table 1). tively (57% of those who suffered preoperatively no longer reported dizziness or imbalance during follow-up). How- Cyst Volume Measurements ever, their test results did not improve postoperatively. In The mean cyst volume in patients who declined surgery the arachnoid cyst patients in our study, the dizziness/im- was 44 ml (SD 36.7 ml, median 27.8 ml) and did not dif- balance may have had causes other than the arachnoid cyst, and, if at all related to the arachnoid cyst, this symptom fer from patients who underwent surgery (p = 0.96). Pa- did not respond to surgical decompression despite subjec- tients with symptoms unrelated to their arachnoid cyst had tive reports of improvement. Furthermore, perhaps surpris- a smaller mean arachnoid cyst volume of 18 ml (SD 20.8 ingly, the performance of patients with a posterior fossa ml, median 9.8 ml) than patients who accepted surgical arachnoid cyst did not differ from those with arachnoid treatment and those who declined surgery (p = 0.0025 and cysts in other locations preoperatively, but had deteriorated p = 0.0006, respectively). following surgical treatment. However, the difference be- tween pre- and postoperative results within this group was Discussion statistically significant only on the Romberg test, possibly In this prospective study on adult patients with arachnoid due to the small number of patients. cysts, we found no differences in the test results of patients Complaints of cognitive disturbances are often associ- considered to be symptomatic and those whose symptoms ated with arachnoid cysts and have been used as a justi- were not considered to be related to their arachnoid cyst. fication for surgical treatment, especially in the case of Furthermore, arachnoid cyst location did not influence temporal arachnoid cysts.21 Our results do not show that a the results of any of the performed tests. The majority of temporal arachnoid cyst causes cognitive disturbances but the surgically treated patients (77%) rated themselves as rather confirm the quiescent nature of arachnoid cysts.13 having improved at follow-up. However, only 43% had Furthermore, following surgery, the only significant dif- complete remission of at least 1 preoperative symptom. ference in the neuropsychological test results of surgically Furthermore, the test results did not improve in those who treated patients was impaired performance on the target underwent surgical treatment. Half of the patients who de- reaction time test. clined surgical treatment (50%) improved spontaneously The high improvement rates reported in previous within 3 months and 86% within the 1st year. studies have also been used to justify surgical treatment, The main strength of our study is the prospective de- despite the risk of complications. The evaluation of im- sign, the defined population, the extensive preoperative provement diverges considerably. In accordance with most and postoperative examinations, and the volumetric mea- previous studies, we found a high rate of improvement surement of the arachnoid cyst volume. However, the study (77%) when asking patients about the evaluation of their is uncontrolled, and the follow-up time is relatively short. symptoms. However, the rate of improvement drops to less A primary arachnoid cyst is a benign condition and than half when total remission of at least 1 symptom is is often found incidentally, with a reported prevalence of required. We speculate that patient-reported improvement 2% and no association with the most common symptoms rates, at least in part, might reflect the impact of anxiety of

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Unauthenticated | Downloaded 09/25/21 05:26 AM UTC K. Rabiei et al. being diagnosed with an intracranial lesion and the subse- no role in the study design, the collection and analysis of the data, quent postoperative relief that is unrelated to the arachnoid the data interpretation, or the writing of this paper. cyst itself.27 In fact, in our recent study on children with arachnoid cysts, almost all patients or parents considered the surgery worthwhile, based on the preoperative anxi- References ety connected to the diagnosis of the arachnoid cyst and 1. Al-Holou WN, Terman S, Kilburg C, Garton HJ, Muraszko regardless of the impact of surgery on their symptoms.18 KM, Maher CO: Prevalence and natural history of arachnoid The high rate of improvement may also be spontane- cysts in adults. J Neurosurg 118:222–231, 2013 1 2. Al-Holou WN, Yew AY, Boomsaad ZE, Garton HJ, Mu- ous. In our study, 86% of the 22 patients who declined raszko KM, Maher CO: Prevalence and natural history of surgery eventually improved. Since there was no differ- arachnoid cysts in children. J Neurosurg Pediatr 5:578–585, ence in arachnoid cyst volume between these patients and 2010 those who chose surgery (p = 0.96), this improvement rate, 3. Ali M, Bennardo M, Almenawer SA, Zagzoog N, Smith AA, similar to that of many surgical series, is remarkable. Fur- Dao D, et al: Exploring predictors of surgery and compar- thermore, we found that improvement was unrelated to the ing operative treatment approaches for pediatric intracranial arachnoid cyst volume in the patients who underwent sur- arachnoid cysts: a case series of 83 patients. J Neurosurg Pediatr 16:275–282, 2015 gery, making the disappearance or decompression of the 4. Auschwitz T, DeCuypere M, Khan N, Einhaus S: Hemor- arachnoid cyst as a measure of surgical outcome pointless. rhagic infarction following open fenestration of a large in- In Sweden, the rate of surgery for intracranial arach- tracranial arachnoid cyst in a pediatric patient. J Neurosurg noid cyst in adults has almost doubled over the past 5 years Pediatr 15:203–206, 2015 compared with the study period, according to the Swedish 5. Bingley T: Mental symptoms in temporal lobe and National Board of Health (The National Board of Health temporal lobe gliomas with special reference to laterality of and Welfare, www.socialstyrelsen.se/english, accessed on lesion and the relationship between handedness and brained- March 25, 2016) (Supplemental eFig. 1). The increasing ness; a study of 90 cases of temporal lobe epilepsy and 253 cases of temporal lobe glioma. Acta Psychiatr Neurol use of radiological examinations, together with a common Scand Suppl 120:1–151, 1958 radiological finding, frequently encountered symptoms as- 6. Folstein MF, Folstein SE, McHugh PR: “Mini-mental state”: cribed to it, and a high reported rate of improvement in A practical method for grading the cognitive state of patients surgical series are perhaps the underlying causes. In this for the clinician. J Psychiatr Res 12:189–198, 1975 study, surgery was offered to all patients in whom other 7. Freeman TB, Vawter DE, Leaverton PE, Godbold JH, Hauser causes of their symptoms were ruled out. Yet, the benign RA, Goetz CG, et al: Use of placebo surgery in controlled nature, and what is now known about the natural history trials of a cellular-based therapy for Parkinson’s disease. N of arachnoid cysts,1,2 together with the risk of serious com- Engl J Med 341:988–992, 1999 4 8. Global Burden of Disease Study 2013 Collaborators: Global, plications associated with surgical treatment and the lack regional, and national incidence, prevalence, and years lived of verifiable improvement despite diminished cyst size, with disability for 301 acute and chronic diseases and injuries speak mainly against surgical treatment. in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet 386:743–800, 2015 Conclusions 9. Harrison BJ, Shaw M, Yücel M, Purcell R, Brewer WJ, We found no differences in the neuropsychological Strother SC, et al: Functional connectivity during Stroop task and balance test results of patients with and those with- performance. Neuroimage 24:181–191, 2005 out symptomatic arachnoid cysts. Results on balance and 10. Headache Classification Subcommittee of the International cognitive performance tests did not improve in surgically Headache Society: The International Classification of Head- ache Disorders 2nd edition. Cephalalgia 24 (1 Suppl):8–160, treated patients, despite self-reported improvement and re- 2004 duction in the arachnoid cyst volume. The results of the 11. Hellström K, Lindmark B: Fear of falling in patients with study speak against objectively verifiable improvement af- : a reliability study. Clin Rehabil 13:509–517, 1999 ter surgical treatment in adults with intracranial arachnoid 12. Hellström P, Edsbagge M, Archer T, Tisell M, Tullberg M, cysts. Wikkelsø C: The neuropsychology of patients with clinically diagnosed idiopathic normal pressure hydrocephalus. Neuro- surgery 61:1219–1228, 2007 Acknowledgments 13. Hund-Georgiadis M, Yves Von Cramon D, Kruggel F, Preul We gratefully acknowledge Elisabeth Blomsterwall for physio- C: Do quiescent arachnoid cysts alter CNS functional or- therapeutic assessment of the patients and guidance regarding the ganization?: A fMRI and morphometric study. Neurology interpretation of the balance tests performed, Roberto Doria Medi- 59:1935–1939, 2002 na for volumetric measurements, all members of the Hydrocephalus 14. Karatas M: Central vertigo and dizziness: epidemiology, Research Unit involved in the evaluation and patient care, especially differential diagnosis, and common causes. Neurologist Gudrun Barrows and Gunilla Ahl-Börjesson for coordination of 14:355–364, 2008 the study and investigations involved and for extensive work on the 15. Murray CJ, Vos T, Lozano R, Naghavi M, Flaxman AD, Mi- patient database, and Cecilia Kjellman at Statistiska Konsultgrup- chaud C, et al: Disability-adjusted life years (DALYs) for 291 pen for the statistical analyses. diseases and injuries in 21 regions, 1990–2010: a systematic The study was supported by the Göteborg Foundation for analysis for the Global Burden of Disease Study 2010. Lan- Neurological Research (ISNF), Sahlgrenska University Hospital’s cet 380:2197–2223, 2012 (Erratum in Lancet 381:628, 2013) research foundations, The Göteborg Medical Society and Kristina 16. Osterrieth PA: [The test of copying a complex figure: a con- Stenborg’s Foundation, Edit Jacobson Foundation, the Rune and tribution to the study of perception and memory.] Arch Psy- Ulla Amlöv Foundation, Hjalmar Svensson’s Research Foundation, chol (Geneve) 30:206–356, 1944 (Fr) and the John and Brit Wennerström Foundation. The funders had 17. Peterson BS, Skudlarski P, Gatenby JC, Zhang H, Anderson

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AW, Gore JC: An fMRI study of Stroop word-color interfer- 30. Stroop JR: Studies of the interference in serial verbal interac- ence: evidence for cingulate subregions subserving multiple tions. J Exp Psychol 18:643–662, 1935 distributed attentional systems. Biol Psychiatry 45:1237– 31. Thurstone L, Jeffrey TE: Perceptual Speed: Identical 1258, 1999 Forms. Test Administration Manual. Chicago: Industrial 18. Rabiei K, Högfeldt MJ, Doria-Medina R, Tisell M: Surgery Relations Center, 1966 for intracranial arachnoid cysts in children-a prospective 32. Tschan R, Wiltink J, Adler J, Beutel ME, Michal M: De- long-term study. Childs Nerv Syst 32:1257–1263, 2016 personalization experiences are strongly associated with 19. Rabiei K, Jaraj D, Marlow T, Jensen C, Skoog I, Wikkelsø C: dizziness and vertigo symptoms leading to increased health Prevalence and symptoms of intracranial arachnoid cysts: a care consumption in the German general population. J Nerv population-based study. J Neurol 263:689–694, 2016 Ment Dis 201:629–635, 2013 20. Rabiei K, Tisell M, Wikkelsø C, Johansson BR: Diverse 33. Wiltink J, Tschan R, Michal M, Subic-Wrana C, Eckhardt- arachnoid cyst morphology indicates different pathophysi- Henn A, Dieterich M, et al: Dizziness: anxiety, health care ological origins. Fluids Barriers CNS 11:5, 2014 utilization and health behavior—results from a representative 21. Raeder MB, Helland CA, Hugdahl K, Wester K: Arachnoid German community survey. J Psychosom Res 66:417–424, cysts cause cognitive deficits that improve after surgery. Neu- 2009 rology 64:160–162, 2005 22. Rasmussen BK, Jensen R, Schroll M, Olesen J: Epidemiology of headache in a general population—a prevalence study. J Disclosures Clin Epidemiol 44:1147–1157, 1991 The authors report no conflict of interest concerning the materi- 23. Rey A: L’examen psychologique dans les cas als or methods used in this study or the findings specified in this d’encéphalopathie traumatique. Archives de Psychologie paper. 28:286–340, 1941 24. Ricci M, Graef S, Blundo C, Miller LA: Using the Rey Au- Author Contributions ditory Verbal Learning Test (RAVLT) to differentiate Alz- Acquisition of data: all authors. Analysis and interpretation of heimer’s dementia and behavioural variant fronto-temporal data: Rabiei, Hellström, Tisell. Drafting the article: Rabiei. Criti- Clin Neuropsychol 26: dementia. 926–941, 2012 cally revising the article: Rabiei, Hellström, Tisell. Reviewed 25. Rosset C, Rosset A, Ratib O: General consumer communica- submitted version of manuscript: all authors. Approved the final tion tools for improved image management and communica- version of the manuscript on behalf of all authors: Rabiei. Study J Digit Imaging 18: tion in medicine. 270–279, 2005 supervision: Tisell. 26. Schramm SH, Moebus S, Lehmann N, Galli U, Obermann M, Bock E, et al: The association between stress and head- Supplemental Information ache: a longitudinal population-based study. Cephalalgia 35:853–863, 2015 Online-Only Content 27. Spansdahl T, Solheim O: Quality of life in adult patients Supplemental material is available with the online version of the with primary intracranial arachnoid cysts. Acta Neurochir article. (Wien) 149:1025–1032, 2007 Supplemental eTable 1 & eFig. 1. https://thejns.org/doi/ 28. Steiner TJ, Stovner LJ, Katsarava Z, Lainez JM, Lampl C, suppl/10.3171/​2016.9.JNS161139. Lantéri-Minet M, et al: The impact of headache in Europe: principal results of the Eurolight project. J Headache Pain Correspondence 15:31, 2014 Katrin Rabiei, Institute of Neuroscience and Physiology, c/o 29. Stovner LJ, Haimanot RT: Epidemiology of common head- Department of Neurosurgery, Sahlgrenska University Hospital, ache disorders, in Martelletti P, Steiner TJ (eds): Handbook Blå stråket 5, vån 3, Gothenburg SE-413 45, Sweden. email: of Headache. Milan: Springer, 2011, pp 17–35 [email protected].

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