Surgical treatment for symptomatic arachnoid cysts

During the period from 1983 to 1999, 12 patients with symptomatic arachnoid cyst were treated. The mean patient age was 20.6 years. The most common location was the middle fossa (10 cases). Initial CT scan revealed associated subdural hygroma in 7 patients and hydrocephalus in one. Clinical symptoms were related to increased intracranial pressure, cranio-megaly and seizure. One infant with a huge arachnoid cyst was treated, using a cystoperitoneal (CP) shunt. Four patients underwent membraectomy. Combination CP shunt and membraectomy was performed in 5 patients. The remaining 2 arachnoid cysts were complicated with subdural hygroma and, initially, they were observed conservatively, but hygroma gradually changed to hematoma. One was treated by irrigation and the other hematoma was spontaneously absorbed. Significant complications included extensive subdural effusion in one patient, contralateral chronic subdural hematoma in two, intracranial hypotension in two, and shunt dependency in one. There were no recurrences during the follow-up period (mean 3.6 years).     

Diagnostic method for differentiating external hydrocephalus from simple subdural hygroma

OBJECT: The various terms used to describe subdural fluid collection--"external hydrocephalus", "subdural hygroma", "subdural effusion", "benign subdural collection", and "extraventricular obstructive hydrocephalus"-reflect the confusion surrounding the diagnoses of these diseases. Differentiating external hydrocephalus from simple subdural hygroma may be difficult, but the former appears to be a distinct clinical entity separate from the latter. In this report, the authors present a diagnostic method for differentiating external hydrocephalus from simple subdural hygroma, based on their clinical experience in treating subdural fluid collection after mild head trauma. METHODS: Twenty patients with subdural fluid collection after mild head trauma were included in this study. Ventricle size was measured using a modified frontal horn index (mFHI); that is, the largest width of the frontal horns divided by the bicortical distance in the same plane, instead of the inner table distance. Bur hole trephination was performed on the appearance of a subdural fluid collection thicker than 15 mm on computed tomography (CT), persistent (longer than 4 weeks) or increasing in size, and accompanied by neurological symptoms (confusion or memory impairment). During the procedure, subdural pressure was measured using a manometer before opening the dura mater. Subdural pressure varied among the patients, ranging from 3 to 27.5 cm H2O. Four patients with a subdural pressure greater than 15 cm H2O had hydrocephalus after surgery (p < 0.05). Hydrocephalus developed in a pediatric patient (2 years old) with a subdural pressure of 12 cm H2O. All of the patients in whom hydrocephalus developed after bur hole trephination had had enlarged ventricles (mFHI > 33%) on preoperative CT scans. CONCLUSIONS: Monitoring subdural pressure may be a valuable tool for differentiating subdural hygroma from external hydrocephalus in patients with mild head trauma. Additionally, the mFHI reflects the nature of the subdural collection more accurately than the standard frontal horn index.     

Transcutaneous pressure adjustable valve for the treatment of hydrocephalus and arachnoid cysts in adults

Summary The authors report a series of 75 adults treated over the last four years for hydrocephalus (69 cases) or arachnoid cysts (6 cases) by using a transcutaneous pressure adjustable valve (Sophy SU 8), the mechanism of which is recalled.The shunt was ventriculo-atrial 46 times, ventriculo-peritoneal 23 times and cysto-peritoneal 6 times. The opening pressure of the valve was initially adjusted 56 times to the medium, 9 times to the high, and 10 times to the low position, according to each particular patient's needs. Following the evolution of the neurological status and/or the CT findings, the opening pressure was secundarily modified in 27 patients (i.e., in 36%), and in some of them several times.It was raised 16 times: 10 times because of subdural hygroma(s) (complicated by a subdural haematoma which required surgical removal, in one case), and 6 times because of clinical symptoms of intracranial hypotension associated with hyperdrainage signs on CT.It was diminished 20 times because of the absence of clinical improvement and persistence of dilated ventricles on CT.In these 27 patients the Sophy SU 8 valve allowed modification of its opening pressure according to the clinical and CT evolution, without need for re-operation.It is concluded that the patients who can benefit most from this valve system are patients with normal pressure hydrocephalus or with arachnoid cysts.     

Subdural hygroma as a complication of endoscopic neurosurgery--two case reports

Two cases of subdural hygroma occurred in a series of 77 neuroendoscopic procedures. An 8-year-old boy underwent neuroendoscopic cysto-cisternostomy of a left temporal arachnoid cyst. Routine postoperative magnetic resonance imaging 7 days later showed a large left-sided subdural hygroma without clinical symptoms. During the following 3 months, the subdural hygroma did not resolve spontaneously, so it was drained through a burr hole. A 3-month-old boy with aqueductal stenosis developed bilateral subdural hygromas after third ventriculostomy. Several punctures through the open anterior fontanelle relieved the hygromas but increasing head circumference required ventriculoperitoneal shunting 12 months later. Complications of neuroendoscopic procedures are increasingly reported, including various kinds of bleeding, infections, or damage of neuronal tissue. Only three previous cases of subdural hygroma or hematoma after neuroendoscopic interventions have been reported. The possible etiologies and clinical consequences of this rare complication have to be considered before selecting neuroendoscopy treatment.     

Ventricular dilation during the treatment of subdural hygromas]

Fifty-one cases with subdural hygroma experienced in the past 20 years were retrospectively reviewed. Eight patients showed definite ventricular dilation differing from simple restoration of the ventricles following disappearance of the cavity. The mean age was 72.4 years. Six patients presented with mental change as the initial symptom. On the initial computed tomography (CT), 75% of the cases had bilateral lesions, all were low density, and 88% were crescent shaped. Trepanation performed on six patients yielded watery clear or xanthochromic fluid. Nine to 61 days (mean 4 weeks) after admission, definite ventricular dilation was observed. Cisternography performed in four patients was all abnormal, although cerebrospinal fluid (CSF) pressure was within normal range. Cerebral blood flow images using 123I-iodoamphetamine and single photon emission CT in four patients revealed periventricular low uptake which was disproportionately large compared with the ventricular span on CT. A ventriculoperitoneal shunt was placed in four patients. The final outcome, however, was poor irrespective of treatment. These findings indicate that an impairment of the CSF circulation was not the sole cause of the ventricular dilation. Low CSF pressure and the disproportionately large periventricular low perfusion, compared with the ventricular span on CT scan, suggest a pre-existing periventricular parenchymal damage, which had been subsequently compromised by the presence of subdural mass lesion. Therefore, attention should be paid in aged patients with bilateral low dense, crescent-shaped subdural hygroma, presenting with mental change, for the risk of subsequent ventricular dilation which may affect the functional outcome.     

Image-guided epidural blood patch as effective treatment of intracranial hypotension. A case report

We report the case of a patient with postural headache. A CT scan revealed bilateral subdural hygroma. Brain MRI showed diffuse pachymeningeal enhancement. A diagnosis of intracranial hypotension was therefore made. Thoracic cerebrospinal fluid leak was proved by radionuclide cisternography and contrast myelography. Conservative medical treatment was ineffective. Two thoracic epidural blood patches with radiographic control were made. We think the blood patch is the most important element for success.     

Management of infratentorial subdural hygroma complicating foramen magnum decompression: a report of three cases

Decompression of the foramen magnum for symptomatic Chiari malformation attends a small but significant risk of infratentorial subdural extra-arachnoid hygroma when an arachnoid-sparing procedure is attempted. We present three cases whereby an arachnoid-sparing procedure was carried out and resulted in infratentorial subdural hygroma and hydrocephalus. The complication was managed by re-exploration of the posterior fossa and wide arachnoidotomy. In cases whereby the decision has been made to open the dura, we recommend routine arachnoidotomy in foramen magnum decompression, avoiding the risks of infratentorial subdural hygroma. In cases where arachnoid-sparing procedures have been attempted and subdural hygroma subsequently develops, we advocate re-exploration of the posterior fossa rather than cerebrospinal fluid diversion.     

Symptomatic Subdural Hygroma and Temporal Lobe Edema After Translabyrinthine Removal of Acoustic Neuroma

The translabyrinthine approach is familiar to most neurosurgeons and neuro-otologists and is frequently used to remove acoustic neuromas. Some of the complications associated with this surgery include cerebrospinal fluid (CSF) leaks, meningitis, and rarely fat graft prolapse. The authors report a 60-year-old woman who underwent a translabyrinthine approach and microsurgical resection of a right-sided 1-cm acoustic neuroma. Initially, she was discharged home after an uneventful postoperative course. Four days later, she sought treatment in the emergency room complaining of headaches, dizziness, and lethargy. A computed tomographic (CT) scan showed a large right-sided subdural hygroma and right temporal lobe edema. The patient underwent burr hole evacuation of the collection and placement of a subdural drain, after which the edema in the temporal lobe and hygroma resolved. We speculate that the underlying mechanism was the result of inadvertant damage to the venous drainage and an arachnoid tear that was not appreciated during surgery. Neurosurgeons and neuro-otogists should be aware of this unusual complication of translabyrinthine surgery and its possible underlying mechanisms.     

Intracranial hypovolemic syndrome with subdural hygroma developed massive hematoma: timing of treatment and histology of dural hypertrophy

We report a case of a 43-year-old man treated by craniotomy for chronical subdural hematoma (CSH) due to spontaneous intracranial hypovolemia. The patient complained of sudden onset severe headache. Initial CT scan showed normal brain structure, and his headache improved with bed rest in a few days. However, MR images obtained for vertigo one month later demonstrated bilateral subdural hygroma extending to the supracerebellar space and diffuse dural enhancement after gadolinium infusion. We diagnosed bilateral subdural hygroma due to spontaneous intracranial hypovolemia, and observed him conservatively. Four months after onset, he complained of severe headache again and MR images revealed enlargement of bilateral CSH with mass effect, which had heterogenous intensity on the right convexity. We evacuated hematoma on the right by craniotomy and aspirated the left side hematoma using a burr hole. His headache improved 2 weeks after the operation with strict bed rest. The follow-up MR images showed disappearance of abnormal meningeal enhancement and improvement of brain sagging.     

Protein analysis of subdural hygroma fluid

Summary The pathogenesis of posttraumatic subdural hygroma still remains largely unknown. One of the suggested pathological mechanisms is the traumatic development of an arachnoid tear and the subsequent efflux of CSF into the subdural space. We performed a multifactorial analysis of the hygroma fluid obtained at operation in comparison to the simultaneously taken plasma and lumbar CSF. The results of the protein analysis support the CSF origin of the subdural hygroma fluid.     

Posterior fossa subdural hygroma with supratentorial chronic subdural haematoma

Posterior fossa subdural hygromas are very rare. They tend to occur following direct occipital trauma. We present an unusual case of complex subdural hygroma of the posterior fossa, which was associated with a supratentorial chronic subdural haematoma. This developed after an apparently minor injury to the head. The unusual features of our case are discussed. We also review the literature and discuss the natural history and pathogenesis of subdural hygroma.     

The clinical course of surgically treated posttraumatic subdural hygromas

Summary The clinical course of 11 patients with a subdural hygroma, who underwent neurosurgery, was studied. In the first week after the operation no improvement of the mental status could be detected. We considered therefore that operation hardly contributed to improvement. Thus the need to operate is limited to special cases such as acute or space-occupying subdural hygroma.     

Subacute subdural hygroma and presyrinx formation after foramen magnum decompression with duraplasty for Chiari type 1 malformation

A 15-year-old girl developed a rare case of subdural hygroma after foramen magnum decompression for Chiari type 1 malformation manifesting as rapid symptom deterioration around 10 days after uncomplicated operation with uneventful immediate postoperative course. Progressive enlargement of the subdural hygroma in both supra- and infratentorial spaces was followed by the development of hydrocephalus. Syringomyelia improved shortly after the first operation but then deteriorated with massive presyrinx formation. Reoperation with wide opening of the arachnoid membrane lead to a rapid resolution of the hydrocephalus and the presyrinx. The present case shows that wide opening of the arachnoid membrane is an effective therapeutic option.     

Symptomatic subdural hygroma after petroclival meningioma surgery. Case report of a intractable complication

Although subdural hygroma development after craniotomy or aneurysm surgery is a well-known complication and subdural peritoneal or V-P shunt are commonly successful procedures, there are situations that cannot be treated by available surgical options. We reported a case of a 28-year-old young man who developed a symptomatic subdural hygroma after removal of petroclival meningioma. This hygroma increased in size and became bilateral in spite of implantation of V-P with programmable valve at open pressure variable from 30 to 180 mmH2O, placement of subdural-peritoneal shunt with low-low valve or without valve and external diversion. The occurrence of this case showed that there other factors can play role in hygroma development as disturbance of normal CSF dynamic with shunt of CSF from basal arachnoidal to subdural spaces secondary to surgery and/or slow growth of petroclival meningioma as well as postoperative progressive cerebral atrophy. Actually there are not effective diagnostic tools to detect causes and therefore, there are restricted therapeutic possibilities. This potential and serious complication should be always considered when planning petroclival meningioma surgery because of the severe consequences on functional outcome.     

Arachnoid cysts in adults: long-term follow-up of patients treated with internal shunts to the subdural compartment

BACKGROUND: We have previously presented an alternative method for surgical decompression of intracranial arachnoid cysts. This minimally invasive method, with insertion of an internal shunt from the cyst to the subdural compartment, seemed to be an efficient and simple, and hence promising technique. The aim of the present study was to investigate the long-term results of this procedure. METHODS: This study is a questionnaire-based retrospective study that includes 31 adult patients (>18 years) who were operated on in our department for an arachnoid cyst in the temporal fossa or overlying the frontal convexity with the internal shunt technique between April 1990 and October 2003. Follow-up ranged from 15 months to 14.8 years (mean = 8.2 years). RESULTS: Of the patients, 83% were asymptomatic or had insignificant complaints at follow-up. A total of 17% reported no reduction of the preoperative complaints. No patient experienced worsening of the symptoms. The cyst was no longer visible on postoperative radiologic examinations in 37% of the patients. In 37%, the postoperative fluid volume was less than 50% of the original volume. In 13%, the cyst volume was reduced but the postoperative volume was greater than 50% of the original cyst volume. Thus, the cyst was unchanged in only 13% of the patients. There was no correlation between volume reduction and clinical improvement. A complication (subdural hygroma or hematoma) occurred in 7 patients, all with temporal cysts, leading to reoperation in 4. None of the complications caused permanent neurologic deficits or invalidity. Seven patients were reoperated on because of suspected or established treatment failure. CONCLUSIONS: The internal shunt technique is a relatively simple, safe, and efficient alternative method for treatment of arachnoid cysts. It should be considered a valuable alternative in the treatment of arachnoid cysts.     

Post-operative spinal subdural extra-arachnoid hygroma causing cauda equina compression: a report of two cases

We present two cases of symptomatic, post-lumbar surgery cauda equina compression due to formation of a dissecting subdural extra-arachnoid cerebrospinal fluid (CSF) collection (hygroma) under tension. In both cases, a small inadvertent durotomy was sustained during the initial surgery. Surgical re-exploration confirmed a tension subdural extra-arachnoid hygroma due to one-way flow of CSF through a pinhole puncture in the arachnoid. The mechanism and clinico-radiological features of this rare post-operative complication are discussed.     

Incidence and risk factors for post-traumatic hydrocephalus following decompressive craniectomy for intractable intracranial hypertension and evacuation of mass lesions

There continues to be a considerable interest in decompressive craniectomy in the management of severe traumatic brain injury (TBI). Though technically straightforward, the procedure is not without significant complications. In this study we assessed the incidence and risk factors for the development of subdural hygroma and hydrocephalus after decompressive craniectomy. A total of 195 patients who had had a decompressive craniectomy for severe TBI between 2004 and 2010 at the two major trauma centers in Western Australia were considered. Of the 166 patients who survived after the acute hospital stay, 93 (56%; 95% confidence interval [CI] 48,63%) developed subdural hygroma; 45 patients (48%) had unilateral and 48 patients (52%) had bilateral subdural hygromas. Of the 159 patients who survived more than 6 months after surgery, 72 (45%; 95% CI 38,53%) developed radiological evidence of ventriculomegaly, and 26 of these 72 patients (36%; 95% CI 26,48%) developed clinical evidence of hydrocephalus and required a ventriculoperitoneal (VP) shunt. Maximum intracranial pressure prior to decompression (p=0.005), subdural hygroma (p=0.012), and a lower admission Glasgow Coma Scale score (p=0.009), were significant risk factors for hydrocephalus after decompressive craniectomy. Hydrocephalus requiring a VP shunt was associated with a higher risk of unfavorable neurological outcomes at 18 months (odds ratio 7.46; 95%CI 1.17,47.4; p=0.033), after adjusting for other factors. Our results showed a clear association between injury severity, subdural hygroma, and hydrocephalus, suggesting that damage to the cerebrospinal fluid drainage pathways contributes to the primary brain injury rather than the margin of the craniectomy as the factor responsible for these complications.     

Spontaneous evolution of posttraumatic subdural hygroma into chronic subdural haematoma

Summary Thirteen of 145 patients with post-traumatic subdural hygroma (SDHy) developed chronic subdural haematoma (CSDH) at the involved site over a period of 6 years. CSDHs were found at the site of SDHys with no history of further head injury at a mean interval of 56 days. It appeared that these 13 patients did not have any distinguishing clinical features early on. Old age and brain atrophy on CT scans do not seem to be reasonable causative factors in the evolution of SDHy into CSDH. Initial enlargement of subdural accumulations at an early stage of SDHy and a subsequent increase in density at a later stage may point to the development of CSDH from SDHy in some instances. Ten of these 13 CSDH cases underwent surgical drainage, and the remaining 3 cases received no specific management. All resolved completely. The prognosis was good in all patients. The possible mechanism for the evolution of SDHy into CSDH is discussed.     

Delayed evolution of posttraumatic subdural hygroma

Five hundred and forty-six patients in a consecutive series of 1,601 patients with craniocerebral trauma had computed tomography. One hundred and ninety-six patients had a follow-up CT scan. Thirteen patients (6.6%) developed apparently "silent" subdural hygromas of delayed evolution noted from six to 46 days after injury (average 22 days). Three of 10 patients (30%) improved after operation. No patient with a severe cerebral deficit (decortication or decerebration) improved. The three unoperated hygromas and the six that persisted after operation tended to resolve spontaneously. The infrequent and modest improvement following surgical treatment and the tendency to spontaneous resolution suggest that operation may be unnecessary in many patients with posttraumatic subdural hygroma of delayed evolution.     

Middle fossa arachnoid cyst presenting an interesting clinical course: a case report

The mechanism of the disappearance of arachnoid cysts is not fully understood. We report a case of arachnoid cyst which disappeared after head injury. A 28-year-old male was found to have an arachnoid cyst in the left middle fossa following head injury. We followed him up, because he had no symptoms. Two weeks later, he suffered from severe headache. CT image showed a dilatation of the subdural space, and his symptom deteriorated. We performed subdural-perifocal shunt, but one month after, he developed a subdural hematoma. The subdural hematoma was irrigated through a burr hole. His symptom disappeared post operatively. Two months later, CT image showed the disappearance of subdural hematoma and the arachnoid cyst. This case suggested one of the mechanisms involved in the disappearance of arachnoid cyst after head injury.