Subarachnoid drainage of an established or chronic pseudomeningocele

Incidental dural tears are a common complication of lumbar spine surgery, but if unrecognized cerebrospinal fluid (CSF) leakage can lead to the formation of a fistula or pseudomeningocele. Traditionally, fistulae and pseudomeningoceles have been treated with open revision surgery, but acute fistulae with direct CSF leakage through the incision site have reportedly been treated by extracorporal drainage. This report presents a case in which an established or chronic pseudomeningocele was successfully managed without open surgical repair.     

Surgical procedures for posterior fossa tumors in children: does craniotomy lead to fewer complications than craniectomy?

OBJECT: Traditionally, access to the posterior fossa involved a suboccipital craniectomy. More recently, posterior fossa craniotomies have been described, although the long-term benefits of this procedure are not clear. The authors compared the postoperative complications of craniectomies and craniotomies in children with posterior fossa tumors. METHODS: From a total of 110 children undergoing surgery for posterior fossa tumors, 56 underwent craniectomy and 54 had a craniotomy. The mean duration of the hospital stay was longer in the craniectomy group (17.5 compared with 14 days). At operation, similar numbers of patients in both groups had total macroscopic clearance of the tumor, complete dural closure, and duraplasty. Postoperatively, more patients in the craniectomy group were noted to have cerebrospinal fluid (CSF) leakage (27 compared with 4%; p < 0.01) and pseudomeningoceles (23 compared with 9%; p < 0.05). There was no significant difference between the two groups in the numbers of patients with CSF infections, wound infections, or hydrocephalus requiring permanent CSF drainage. Patients with CSF leaks had a longer duration of hospital stay (20.7 compared with 14.9 days; p < 0.01), and were more likely to have CSF infections (35 compared with 12%; p < 0.01) and wound infections (24 compared with 1%; p < 0.01) than patients without CSF leaks. Postoperatively, wound exploration and reclosures for CSF leakage were more likely in the craniectomy group (11 compared with 0%; p < 0.01). Multivariate analysis revealed that the only predictor of CSF leakage postoperatively was the type of surgery (that is, craniotomy compared with craniectomy; odds ratio 10.8; p = 0.03). CONCLUSIONS: Craniectomy was associated with postoperative CSF leaks, pseudomeningocele, increased wound reclosures, and thus prolonged hospital stays. In turn, CSF leakage was associated with infections of the CSF and wound. The authors propose mechanisms that may explain why CSF leakage is less likely if the bone flap is replaced.     

Reconstruction after retrosigmoid approaches using autologous fat graft-assisted Medpor Titan cranioplasty: assessment of postoperative cerebrospinal fluid leaks and headaches in 60 cases

Background

Postoperative cerebrospinal fluid (CSF) leaks and headaches remain potential complications after retrosigmoid approaches for lesions in the posterior fossa and cerebellopontine angle. The authors describe a simple repair technique with an autologous fat graft-assisted Medpor Titan cranioplasty and investigate the incidence of postoperative CSF leaks and headaches using this technique.

Methods

A retrospective chart review was conducted on all cases (n?=?60) of retrosigmoid craniectomy from September 2009 to May 2014 in patients who underwent fat graft-assisted cranioplasty. After obtaining a watertight dural closure and sealing off any visible mastoid air cells with bone wax, an autologous fat graft was placed over the dural suture line and up against the waxed-off air cells. The fat graft filled the retrosigmoid cranial defect and was then bolstered with a Medpor Titan (titanium mesh embedded in porous polyethylene) cranioplasty. A postoperative mastoid pressure dressing was applied for 48 h, and prophylactic lumbar drainage was not used. Factors examined in this study included postoperative CSF leak (incisional, rhinorrhea, otorrhea), pseudomeningocele formation, incidence and severity of postoperative headache, length of hospital stay, and length of follow-up.

Results

No patients developed postoperative CSF leaks (0 %), pseudomeningoceles (0 %), or new-onset postoperative headaches (0 %) with the described repair technique. There were no cases of graft site morbidity such as hematoma or wound infection. Mean duration of postoperative hospital stay was 3.8 days (range 2–10 days). Mean postoperative follow-up was 12.4 months (range 2.0–41.1 months).

Conclusions

Our multilayer repair technique with a fat graft-assisted Medpor Titan cranioplasty appears effective in preventing postoperative CSF leaks and new-onset postoperative headaches after retrosigmoid approaches. Postoperative lumbar drainage may not be necessary.     

Management of pseudomeningocele following neurotologic procedures.

OBJECTIVES: A pseudomeningocele results from the escape of cerebrospinal fluid through a dural defect with trapping of subarachnoid fluid in surrounding soft tissue. The present study evaluates the incidence of pseudomeningocele following neurotologic procedures and delineates an algorithm for management. METHODS: A retrospective review of 375 consecutive patients undergoing neurotologic procedures at a single institution identified 17 patients with the postoperative complication of pseudomeningocele. RESULTS: The incidence of pseudomeningocele formation was 4.5% in the present study. Fourteen pseudomeningoceles resolved with nonoperative management including pressure dressing, bed rest, and lumbar spinal drainage. Three patients failed nonoperative management and required surgical procedures for resolution. All patients ultimately had resolution of their pseudomeningocele. CONCLUSION: Skull-base pseudomeningoceles occur as a complication following neurotologic procedures and can cause complications as they enlarge. The majority of these cases can be dealt with in a nonsurgical manner, but those failing to respond to conservative management should be considered for surgical intervention.     

Lumbar peritoneal shunting with video-laparoscopic assistance: a useful technique for the management of refractory postoperative lumbar CSF leaks

BACKGROUND: Cerebrospinal fistulas and pseudomeningoceles can occur after lumbar spinal surgery, and are sometimes refractory to direct repair, external drainage, and blood patches. The authors report a technique for cerebrospinal fluid (CSF) diversion from the lumbar spine to the peritoneum to assist with the management of these difficult situations. METHODS: Using video-laparoscopic assistance, two shunts are placed from the lumbar region into the peritoneal cavity: first, a lumbar subarachnoid space to peritoneum shunt; and second, a meningocele cavity to peritoneum shunt. Patients are ambulated immediately after the procedure. External drains are not used. RESULTS: Four patients with refractory CSF leaks were successfully managed with this technique. Complications associated with prolonged bedrest and external drains were avoided. Ancillary procedures were minimized, and hospital stay was shortened. Laparoscopic assistance offered verification of accurate placement of the peritoneal catheter and shortened operative times. CONCLUSIONS: Dual lumbar peritoneal shunts (intrathecal-peritoneal and meningocele cavity-peritoneal), placed with laparoscopic assistance, proved effective in the management of four patients with postoperative lumbar CSF leaks, who had failed to respond to conventional treatment.     

Migrating pseudomeningocele causing posterior fossa syndrome

We present two cases of spontaneous intracerebellar migration of a pseudomeningocele. This is a rarely reported complication of posterior fossa surgery with possible life threatening cerebellar mass effect. The probable mechanism is a slow but progressive cerebrospinal fluid (CSF) movement (one-way valve mechanism) into the pseudomeningocele with secondary herniation or dissection through a weakened dura into the cerebellum causing progressive or acute cerebellar dysfunction. Evacuation and dural repair with or without CSF shunting or marsupialisation results in resolution of the symptoms.     

Delayed Cerebrospinal Fluid Leak after Watertight Dural Closure with a Polyethylene Glycol Hydrogel Dural Sealant in Posterior Fossa Surgery: Case Report

A polyethylene glycol (PEG) hydrogel sealant recently has been approved as an adjunct to sutured dural closure in Japan. We treated consecutive six patients with PEG hydrogel sealant in posterior fossa operation. Three of six cases suffered delayed cerebrospinal fluid (CSF) leak after watertight dural closure with the PEG hydrogel sealant, although there was no leak case which was treated with fibrin glue, before 2 years until the adoption of the new material. These patients underwent posterior fossa craniotomy and discharged without remarkable CSF leak. The pseudomeningocele under the occipital wound caused the CSF leak occurr from 5th to 7th week postoperatively. All CSF leak cases needed surgical repair. At the repair, the PEG hydrogel was liquefied and almost absorbed. A fistula on the closure line and a dead space after the absorption of the PEG hydrogel was observed. When the absorbable PEG hydrogel sealant plugs in small gaps of sutured dura, its properties to prevent adhesion might suppress healing process of dural closure, so that CSF could leak through the gaps and collect as a pseudomeningocele in the dead space after absorption of the PEG hydrogel. In posterior fossa surgery a PEG hydrogel sealant should be applied when dural edges are closed tightly without any gaps.     

MRI study of the natural history and risk factors for pseudomeningocoele formation following postfossa surgery in children

Surgical approaches to the posterior fossa may be complicated by pseudomeningocoele formation. We report on its natural history and risk factors for its formation, as seen on serial MRI postoperatively in children with posterior fossa tumours. In a retrospective study of 84 children undergoing surgery for posterior fossa tumours, 13 (16%) developed clinically apparent pseudomeningocoeles. On postoperative MRI, pseudomeningocoeles were apparent in 34 (41%) patients at 1-5 days, but in only four patients at 10-15 months postsurgery. There was a progressive decrease in the mean depth of pseudomeningocoele measured from the MRI scans postoperatively. Patients with pseudomeningocoeles were more likely to have a postoperative CSF leak from the wound (39 v. 13%), lumbar punctures or lumbar drains (54 v. 25%), wound re-closures (23 v. 1%) and prolonged hospital stay (19.9 v. 14.5 days). On multivariate analysis, patients with pseudomeningocoeles were also more likely to have undergone a suboccipital craniectomy than those without pseudomeningocoeles (69 v. 38%). Postoperative pseudomeningocoele formation following posterior fossa surgery is more apparent radiologically than clinically, but there is clinical and radiological evidence that pseudomeningocoeles gradually resolve over the postoperative period. The risk of pseudomeningocoele formation is increased by performing a suboccipital craniectomy and there is an association with increased CSF leaks, needing re-closure of the wounds.     

Pertreatment radiation induced oedema causing acute hydrocephalus after radiosurgery for multiple cerebellar metastases

Summary ¶Background. Most complications of radiosurgery occur after 6–12 months and some long term complications up to after 5–10 years. Although severe, immediate side effects are rare, we report a patient who shows that this possibility should be taken into account when large volumes are treated especially in the posterior fossa. Case report. A patient was treated with radiosurgery for multiple brain metastases, of which 5 were located in the posterior fossa. Deterioration occurred, radiosurgery was halted abortion and CT showed acute hydrocephalus caused by a significant edema in the posterior fossa, not present in an MR examination performed some 6 hours earlier. After intubation and external ventricular CSF drainage, a permanent shunt was inserted, the edema resolved, and the patient recovered to her pretreatment condition within 10 days. The remaining metastases were treated during the first session and MR images showed the hydrocephalus resolved when all the radiated tumors had significantly decreased in size. Interpretation. Care should be taken when treating with radiosurgery patients posterior fossa metastases and signs of compressed CSF pathways. Exceptionally, an acute radiation induced edema could result in a block of the CSF pathways, necessitating a surgical intervention. Prophylactic shunt insertion or hospitalization the night following the treatment should be considered.Published online July 23, 2003     

Closed continuous drainage of cerebrospinal fluid via a lumbar subarachnoid catheter for treatment or prevention of cranial/spinal cerebrospinal fluid fistula.

One hundred and seven patients who had a lumbar subarachnoid catheter (teflon or silicone) placed for closed continuous cerebrospinal fluid (CSF) drainage between 1983-1991 are presented. Overall, the drain was successful in achieving the desired goal in 101 of 107 (94%) cases. There were no deaths. Five of 107 (5%) patients developed infections including two cases (2%) of meningitis. There were three cases (3%) of overdrainage with temporary neurologic decline, but all recovered. Five of fifteen (33%) teflon catheters required replacement because of occlusion, but only 5 of 92 (5%) silicone catheters required replacement. Transient lumbar nerve root irritation was seen in 15 of 107 (14%) patients treated for a CSF fistula, and all symptoms resolved after drain removal. CSF fistula/pseudomeningocele after spine surgery was cured by CSF drainage in 36 of 39 (92%) cases; there was a 10% incidence of infection (1 wound, 2 discitis, 1 meningitis). CSF fistula after cranial surgery was cured in 22 of 25 (87%) cases; there was 1 case of (4%) infection and 1 case (4%) of overdrainage. A drain was used to augment a tenuous dural closure in 38 patients with 100% success; no infection occurred and there were 2 cases (5%) of overdrainage. Five patients were successfully treated for traumatic CSF rhinorrhea/otorrhea without complications. The silicone catheter appears superior to the teflon catheter; however, both are simple, safe, and efficacious for the treatment or prevention of CSF fistulas.     

Spinal cord compression from traumatic anterior cervical pseudomeningoceles. Report of three cases

Pseudomeningoceles rarely develop after cervical trauma; in all reported cases the lesions have extended outside the spinal canal. The authors report the first known cases of anterior cervical pseudomeningoceles contained entirely within the spinal canal and causing cord compression and neurological injury. The authors retrospectively reviewed the cases of three patients with traumatic cervical spine injuries and concomitant compressive anterior pseudomeningoceles. The lesion was recognized in the first case when the patient's neurological status declined after he sustained a severe atlantoaxial injury; the pseudomeningocele was identified intraoperatively and decompressed. After the decompressive surgery, the patient's severe tetraparesis partially resolved. In the other two patients diagnoses of similar pseudomeningoceles were established by magnetic resonance imaging. Both patients were treated conservatively, and their mild to moderate hemiparesis due to the pseudomeningocele-induced compression abated. The high incidence of anterior cervical pseudomeningoceles seen at the authors' institution within a relatively brief period suggests that this lesion is not rare. The authors believe that it is important to recognize the compressive nature of these lesions and their potential to cause devastating neurological injury.     

Cerebrospinal fluid leakage after posterior fossa surgery may impair brain metabolite clearance

The discovery of the important role of cerebrospinal fluid (CSF) drainage of cerebral metabolite waste, known as the glymphatic system, has changed our view of brain waste clearance. We recently performed experiments to evaluate the glymphatic system in non-human primates (NHP). Here, we report the case of an NHP with iatrogenic CSF leakage. In this animal, solute transport through the brain, assessed by gadolinium injection in the CSF, was severely impaired by iatrogenic pseudomeningocele. This observation raises an important question: does brain surgery, and particularly posterior fossa surgery, lead to chronic impairment of parenchymal CSF circulation and solute transport?     

Utilization of preoperative cerebrospinal fluid drain in skull base surgery.

OBJECTIVE: Retrospectively assess the efficacy of lumbar cerebrospinal fluid (CSF) drainage placed preoperatively in skull base operations in decreasing the incidence of postoperative CSF fistula. METHODS: A retrospective review of 150 patients undergoing a posterior fossa craniotomy from 1989 to 2000 was conducted. Patients were divided into those receiving preoperative lumbar drains and those that did not. The rates of postoperative CSF leakage were compared between the two groups. Patient data were analyzed to determine if there were other comorbidities affecting the postoperative incidence of CSF leakage such as smoking, diabetes, or hypertension. RESULTS: Between 1989 and 1994, 25/72 (35%) patients with no preoperative lumbar drain had a postoperative CSF leak. From 1995 to 2000, 9/78 (12%) patients with a preoperative lumbar drain had a CSF leak. This was a 23% decreased incidence of postoperative CSF leakage and a significant decrease in the probability (p < 0.001) of CSF leakage in patients treated with a preoperative lumbar drain. The comorbidities of diabetes, smoking, or hypertension did not increase the probability of a CSF leak (p = 0.43). CONCLUSIONS: A preoperatively placed lumbar drain can significantly lower the rate of postoperative CSF leakage after skull base surgery. The drain is a well-tolerated adjunct to dural closure and helps increase surgical exposure of the posterior fossa. The comorbidities of diabetes, smoking, or hypertension do not contribute to an increased rate of CSF leakage.dagger Lyal Leibrock M.D., F.A.C.S. is Deceased.     

Transient meningism in children after non-autologous duraplasty for Chiari Malformation surgery: A case series

BackgroundIncreasing the posterior fossa volume is the mainstay of treatment for Chiari type 1 Malformation (C1M) and type 1.5 (C1.5M). Different options to restore CSF flow have been described but no consensus has been reached yet. Bony decompression of posterior cranial fossa with dural opening provides good results but at the price of complications such as pseudomeningocele and aseptic meningitis. A single center retrospective analysis was conducted to find any relationships between outcome and perioperative factors. As a second goal a specific analysis was conducted on the complications and their hypothetical causes.MethodsAll the pediatric patients who underwent to posterior fossa bony decompression and dural opening for C1M or C1.5M in the period 2008-2020 were included in the study. A minimum period of three-months follow-up was considered among the inclusion criteria.ResultsA population of fifty-three consecutive patients was collected. Pseudomeningocele and a mild meningeal irritation resulted the most frequent complications. Considering preoperative and intraoperative factors, the type of dural graft showed a relatively strong correlation (P < .01) with pseudomeningocele appearance and the development of meningism. In the latter case, a short course of steroids was the only treatment required to control symptoms.ConclusionsDifferent factors could influence the outcome in Chiari Malformation surgery and eventually the development of complications. An adequate dural graft selection is of paramount importance when a dural opening for posterior fossa augmentation is planned. In case of mild meningeal irritation, a trial with short course steroids could avoid revision surgery.     

Collagen matrix duraplasty for cranial and spinal surgery: a clinical and imaging study

OBJECT: The repair of dural defects is controversial in contemporary neurosurgery. To date, collagen-based products remain a continued area of interest in the development of dural grafts. The authors conducted a prospective case-control study in which they evaluated collagen matrix in the repair of dural defects following cranial and spinal surgery by using specific clinical and magnetic resonance (MR) imaging outcome measures. METHODS: Enrolled in the study were 79 patients, 36 male (45.6%) and 43 female (54.4%), with a mean age of 53 +/- 15.8 years. The pathological diagnosis was brain tumor in 49 cases (62%), vascular conditions in 16 (20.2%), degenerative spine in 10 (12.7%), trauma in two (2.5%), and other in two (2.5%). Most of the patients underwent supratentorial craniotomy (57; 72.2%), whereas 11 patients (13.9%) each underwent posterior fossa and spinal surgery. Sixty-three patients (79.7%) completed the study, which included clinical and MR imaging evaluations at 3 months postsurgery. There were no cerebrospinal fluid (CSF) leaks or delayed hemorrhages. The neurosurgical wound infection rate was 3.8%: superficial wound infection in two cases and deep infection and brain abscess in one case (recurrent brain tumor following radiation therapy). Among the 63 patients in whom 3-month postsurgery imaging data were available, asymptomatic small pseudomeningoceles were detected on MR imaging in two (3.2%); a minor subgaleal fluid collection, which resolved spontaneously, was apparent in another patient (1.6%). Nonspecific dural enhancement was demonstrated on images obtained in seven patients (11.1%), and asymptomatic spinal epidural enhancement was observed on images obtained in two of three patients who had undergone lumbar laminectomy for spinal stenosis. CONCLUSIONS: When used as a dural onlay graft, collagen matrix had a 100% CSF containment rate but might be associated with occult radiological abnormalities.     

Direct pressure on a pseudomeningocele resulting in intraoperative cerebral ischemia

Purpose

When positioning patients with meningocele and meningomyelocele, it is standard practice to avoid direct pressure on the lesions. That caution is intended to prevent injury to neural elements within the lesion and violation of the cerebrospinal fluid space. We herein report an additional hazard of direct intraoperative pressure on such lesions. An adult patient with a lumbosacral pseudomeningocele sustained a cerebral ischemic injury as a consequence of direct pressure on the lesion during general anesthesia.

Clinical features

A 32-yr-old male with spina bifida and a pseudomeningocele related to recent lumbar surgery underwent a urologic procedure in the lithotomy position. Because the lesion was recognized to lie to the left of the midline, cushioning was placed under the patient’s left hip and buttock. The patient was slow to awaken and has sustained significant long-term cognitive deficits. Imaging is consistent with a diffuse cerebral ischemic insult.

Conclusion

In retrospect, the size and leftward extent of the pseudomeningocele were not appreciated preoperatively, and in spite of the care taken, intraoperative pressure was placed on the lesion. This report cautions that intraoperative pressure related to positioning patients with extra-axial lesions containing cerebrospinal fluid (CSF), e.g., meningoceles and pseudomeningoceles, can result in increases in CSF pressure and thereby a reduction in cerebral perfusion pressure sufficient to result in cerebral ischemia.     

Continuous cerebrospinal fluid drainage using a lumbar subarachnoid catheter for cerebrospinal fluid rhinorrhea after functional endoscopic sinus surgery

Anesthesiologists are frequently consulted for performing lumbar cerebrospinal fluid (CSF) drainage to facilitate surgery or manage complications. Functional endoscopic sinus surgery (FESS) is a common treatment for chronic sinus diseases. Cerebrospinal fluid (CSF) leakage is a serious complication following FESS and is typically treated with an endonasal free or rotational mucoperichondrial flap. Continuous drainage of CSF with a lumbar subarachnoid catheter has been used in patients who have undergone neurosurgery but it is seldom used in the treatment of post-FESS CSF rhinorrhea. We present a 71-year-old male patient who suffered from CSF rhinorrhea after FESS, and was treated successfully with continuous lumbar CSF drainage. We are of the opinion that continuous CSF drainage with a lumbar subarachnoid catheter is an effective and safe modality of treatment for post-FESS CSF leakage.     

Sacral fracture with pseudomeningocele and cerebrospinal fluid fistula: case report and review of the literature

A patient who sustained an isolated transverse sacral fracture is presented. A large ventral sacral pseudomeningocele with cerebrospinal fluid (CSF) fistula developed. Eighteen previous cases of traumatic pseudomeningocele have been documented. A review of those cases leads these authors to conclude that: transverse sacral fractures are rare and have not been reported in association with a pseudomeningocele formation; at the 4th sacral vertebra, this is the lowest reported pseudomeningocele; and CSF fistula with sacral fracture is distinctly uncommon, reported in only one previous case. The presenting symptoms, diagnostic evaluation, treatment, and prognosis are discussed.     

腰椎间盘突出症再手术中BAK的应用

目的：本文报告8例腰椎间盘突出症再手术治疗使用BAK作后路植骨融合，目的在于明确手术适应征和探讨BAK在再手术治疗的优点及并发症。方法：对1998-2001年8例腰突症再手术病人的临床资料，影像学资料及手术操作进行分析，6例为原间隙椎间盘再突出，2例为原间隙侧隐窝狭窄。结果：本组病例随访8-30月，全部骨性融合BAK移动、脱落、下陷，术前症状基本消除。结论：严格掌握手术适应证，进行规范操作，腰突症再手术中使用BAK作后路植骨融合是安全、疗效显著。     

Marked reduction of cerebral vasospasm with lumbar drainage of cerebrospinal fluid after subarachnoid hemorrhage

OBJECT: Cerebral vasospasm after subarachnoid hemorrhage (SAH) continues to be a major source of morbidity in patients despite significant clinical and basic science research. Efforts to prevent vasospasm by removing spasmogens from the subarachnoid space have produced mixed results. The authors hypothesize that lumbar cisternal drainage can remove blood from the basal subarachnoid spaces more effectively than an external ventricular drain (EVD). This non-randomized, controlled-cohort study was undertaken to evaluate the effectiveness of a lumbar drain in patients with SAH compared with those in whom an EVD or no form of cerebrospinal fluid (CSF) drainage was used to prevent the development of clinical vasospasm and its sequelae. METHODS: The authors collected data on 266 patients with nontraumatic SAH who were admitted to the University of Utah Health Sciences Center between January 1994 and January 2003. Of these, 167 met the study entry criteria. The treatment group consisted of 81 patients in whom a lumbar drain had been placed for CSF shunting, whereas the control group was composed of 86 patients who received no form of CSF drainage or who were treated solely with an EVD. Primary outcome measures were as follows: 1) clinically evident vasospasm; 2) the need for endovascular intervention; 3) vasospasm-induced infarction; 4) disposition at time of discharge; and 5) Glasgow Outcome Scale (GOS) score at 1 to 3 months postdischarge. Secondary outcomes included length of stay and the need for CSF shunting. The presence of a lumbar drain conferred a statistically significant protective and beneficial effect across all outcome measures, reducing the incidence of clinical vasospasm from 51 to 17%, the need for angioplasty from 45 to 17%, and the occurrence of vasospastic infarction from 27 to 7% (all p < or = 0.001-0.008). Patients in the treatment group were more likely to be discharged home (54% compared with 25%, p = 0.002) and to have a GOS score of 5 at follow up (71% compared with 35%, p < 0.001). The mean number of days spent in the intensive care unit and in the hospital overall was also fewer in the treatment group. A similar degree of benefit was found in patients with different Fisher grades and regardless of whether an EVD was needed on presentation, both by subgroup analysis and multivariate logistic regression modeling. There was no statistical difference between the groups in terms of patients requiring a shunt. Complications with lumbar drains were rare and yielded no permanent sequelae. CONCLUSIONS: Shunting of CSF through a lumbar drain after an SAH markedly reduces the risk of clinically evident vasospasm and its sequelae, shortens hospital stay, and improves outcome. Its beneficial effects are probably mediated through the removal of spasmogens that exist in the CSF. The results of this study warrant a randomized clinical trial, which is currently under way.