Syringosubarachnoid Shunt Research Articles

A critical appraisal of drainage in syringomyelia.

The use of drains in the treatment of syringomyelia has a simple and immediate appeal and has been practiced widely since the report of Abbe and Coley over 100 years ago. Good short-term results have been claimed in the past, but long-term outcome is largely unknown. An experience in Birmingham, England is reviewed in which 73 patients who had had some form of syrinx drainage procedure performed were subsequently followed up. In these cases, a total of 56 syringopleural and 14 syringosubarachnoid shunts had been inserted. Ten years after the operations, only 53.5% and 50% of the patients, respectively, continued to remain clinically stable. A 15.7% complication rate was recorded, including fatal hemorrhage, infection, and displacement of the drain from the pleural and syrinx cavities. At second operation or necropsy, at least 5% of shunts were discovered to be blocked. The effect of other drainage procedures that do not use artificial tubing, such as syringotomy and terminal ventriculostomy, was analyzed but found not to offer any substantial benefit. These results indicate that drainage procedures are not an effective solution to remedying the progressive, destructive nature of syringomyelia. It is suggested that, rather than attempting to drain the syrinx cavity, disabling the filling mechanism of the syrinx is more appropriate. Most forms of syringomyelia have a blockage at the level of the foramen magnum or in the subarachnoid space of the spine. Surgical measures that aim to reconstruct the continuity of the subarachnoid space at the site of the block are strongly recommended. Lowering the overall pressure of the cerebrospinal fluid is advocated when reestablishment of the pathways proves impossible. Syrinx drainage as an adjuvant to more physiological surgery may have a place in the treatment of syringomyelia. If two procedures are done at the same time, however, it is difficult to ascribe with certainty a success or failure, and it is suggested that the drainage procedure be reserved for a later attempt if the elective first operation fails.

Increased pulsatile movement of the hindbrain in syringomyelia associated with the Chiari malformation: cine-MRI with presaturation bolus tracking.

Cine-MRI with presaturation bolus tracking was used in patients with syringomyelia associated with a Chiari malformation to study pulsatile movement of the hindbrain, cervical spinal cord, cerebrospinal fluid and the fluid within the syrinx. Nine patients had 13 examinations, 6 preoperative, 3 after syringosubarachnoid shunting and 4 after posterior fossa decompression. Five controls were also examined. Dynamic display of the acquired images demonstrated downward displacement of the presaturation bolus on the cerebellar tonsils and medulla oblongata (or upper cervical cord) at the C1 level in all preoperative examinations and in two patients after syringosubarachnoid shunting but with residual foramen magnum obstruction. Downward displacement of the bolus on the cervical spinal cord was also demonstrated in 7 examinations, but not observed in the controls. Thus, the hind-brain-spinal cord axis showed larger pulsatile movements in patients with foramen magnum obstruction. Based on these observations and a review of the literature, a new theory on the mode of extension of syringomyelia, emphasising the role of increased pulsatile movement of the hind-brain-spinal cord axis is proposed: that the pulsatile movements, together with a one-way valve mechanism in the syrinx cavity act as a "vacuum-pump" to enlarge the syrinx.

Operative treatment and prognosis of syringomyelia.

Twenty-two patients suffering from syringomyelia were treated operatively. Different shunt procedures were performed. Most often syringo-subarachnoid shunt (seven cases) and syringopleural shunt (eight cases) were used. Operative findings and complications were discussed. Postoperative improvement was observed in five patients, twelve were stable-unchanged, four showed further deterioration and one died. Operative treatment should be performed before gross neurological deficit is established.

An approach to symptomatic children (ages 4-14 years) with Chiari type I malformation.

A review of 16 pediatric patients examined and treated from 1987 to 1991 is presented. The purpose for this review was to examine the different initial clinical presentation in the younger age group versus the older child and to identify the factors impacting on the patients' surgical outcome, including the patients' age, clinical presentation and MRI findings. Patients' ages ranged from 4 to 14 years. Ten were under 6 years of age. Seven males and 9 females were included. The diagnosis was confirmed by MRI in all patients and all were followed by clinical and MRI evaluations for at least 1 year postoperatively. The patients were grouped into three subgroups: (a) group IA patients with a Chiari I malformation, (b) group IB patients with a Chiari I malformation and syrinx, and (c) group IC patients with a Chiari I malformation and hydrocephalus with or without an associated syringomyelic cavity. A uniform surgical approach was used and tailored to the degree of anomalies seen on MRI. Patients with a Chiari IA and IB were treated by a suboccipital craniectomy, upper cervical laminectomy, arachnoidal retraction and duraplasty. Only 1 patient in group B required a syringosubarachnoid shunt initially. Patients with a Chiari IC malformation were treated by a ventriculoperitoneal shunt initially. The clinical presentation of younger children (less than 6 years old) appeared similar to older children (over 6 years of age) except for sleep apnea, which was limited to the younger age group. Patients with pronounced motor and sensory deficits had the worst prognosis for recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Interpleural analgesia: Its use, and a complication, in a quadriplegic patient with chronic benign pain

A 49-yr-old woman sustained a cervical spine fracture at the age of 21 yr as the result of a swimming accident. In 1986, she developed syringomyelia and underwent a C2-3 laminectomy, drainage of the syrinx, and placement of a syringo-subarachnoid shunt. At this time, she became ventilator dependent. Pain had been experienced in the right shoulder, neck, and lateral aspect of the forearm for 3 yr. A series of trigger point injections provided short-term relief, as did a series of stellate ganglion b:ocks. Several injections of steroid into the bursa of the shoulder joint also yielded no sustained relief, and further injections were refused. She was maintained on baclofen 100 mg daily, acetaminophen 350 mg four times daily, hydromorphone 3 mg every 3 hr, and amitriptyline 50 mg twice daily, but this regimen failed to provide adequate analgesia. When she came to the Pain Clinic, examination revealed a ventilated patient with a tracheostomy. There was limited range of motion of her neck, especially on rotation to the right. Neck movement was not painful. The neck was obese, and there was a posterior scar as a result of her previous laminectomy. Neurologic examination revealed flaccid quadriplegia, absent sensation ‘below C,, decreased reflexes in both upper and lower extremities, negative Babinski signs bilaterally, and finger contractures of both hands. Cervical spine radiographs showed demineralization of the lower cervical vertebrae, with no focal abnormality. The remainder of the examination was unremarkable. The right scapular pain was thought to be secondary to cervical osteoarthritis, and the shoulder pain was ascribed to bursitis. Cervical cpidural steroid injections were considered, but were then rejected due to the technical difficulties posed by a patient with an obese short neck, limited range of movement, prior neck surgery, and a tracheostomy band around the neck. A trial of interpleural analgesics was planned. With the patient in the left lateral position, a 17-gauge Tuohy needle was advanced at the T7-8 interspace. The interpleural space was identified using a “passive loss of resistance” technique. This method allows l-2 mI, of air from a syringe to be drawn into the interpleural

Syringomyelia presenting as shoulder instability

Three middle-aged women presented with shoulder instability as the first sign of syringomyelia. The patients' symptoms were unilateral in each case. Two patients had posterior shoulder instability, and one patient had anterior instability. Two patients had undergone surgery to stabilize the shoulder before referral to our center. In both cases the surgery had been unsuccessful. Review of two of the patients' plain radiographs after referral demonstrated radiographic changes highly suggestive of neuropathic arthropathy. The diagnosis of syringomyelia was confirmed by myelography, computed tomographic scanning, and magnetic resonance imaging. One patient had an associated Arnold-Chiari malformation that was treated by a syringosubarachnoid shunt. Each patient's shoulder disability, although significant, remained static throughout a follow-up period averaging 79 months. Shoulder instability can be a presenting symptom and sign of syringomyelia. Patients over age 40 presenting with a glenohumeral dislocation may, in addition to having a high probability of rotator cuff injury, have neuropathic arthropathy. Syringomyelia should be included in the differential diagnosis of shoulder instability so that unnecessary and unsuccessful surgery can be avoided.

Management of syringomyelia associated with chiari malformation: Comparative study of syrinx size and symptoms by magnetic resonance imaging

The authors reviewed the postoperative alteration of symptoms and syrinx size by magnetic resonance imaging (MRI) in 14 consecutive patients with syringomyelia associated with Chiari malformation. The patients were treated according to our treatment regimen and were divided into five groups according to operative modalities: (1) only foramen magnum decompression (D) for small syrinx; (2) D with ventriculoperitoneal (VP) shunt for small syrinx with hydrocephalus; (3) D with syringosubarachnoid (SS) shunt or (4) D with syringoperitoneal (SP) shunt for large syrinx; and (5) only VP shunt for syrinx with hydrocephalus and atlantoaxial dislocation, respectively. From the preoperative and postoperative sagittal MR images, the areas of the spinal cord and syrinx were measured by a digitizer and the syringo-cord (S-C) ratio was calculated. Out of 14 patients, 12 showed a reduction of syrinx size and a stabilization or improvement of symptoms after surgery. In the other two patients, the syrinx size did not change and their symptoms worsened. Magnetic resonance imaging follow-up showed that foramen magnum decompression without shunt is effective for patients with a small syrinx below 35% of the S-C ratio, and foramen magnum decompression with shunt was effective for patients with a large syrinx over 35% of the S-C ratio, but there was no significant difference between the SS and SP shunt group.

Surgical Management of Chiari Malformation and Syringomyelia: Experience in 14 Cases

Our experience with 14 patients afflicted with symptomatic Chiari malformation and syringomyelia, who were treated at King Khalid University Hospital between 1983 and 1990, is analyzed with reference to presentation, management, operative findings, and outcome. Patients with associated myelomeningocele, tethered cord, and spinal cord tumors were excluded from this series. The wide variations in natural history and clinical findings are emphasized. Neuroradiological studies included plain roentgenograms, myelograms, metrizamide-enhanced computed tomograms, and more recently magnetic resonance imaging scans. Posterior fossa decompression was the standard operation; other surgical procedures included syringosubarachnoid shunt, ventriculoperitoneal shunt, transoral odontoid resection, and terminal ventriculostomy. Four patients experienced definite improvement following surgery; the condition in seven was unchanged, and three suffered worsening of the disorder despite operation.

Syringo-subarachnoid shunt for syringomyelia associated with Chiari malformation (type 1)

The authors report the surgical results of 28 patients with syringomyelia associated with Chiari malformation (type 1). 28 patients underwent 34 operative procedures. Syringo-subarachnoid shunt was performed in 28 patients, foramen magnum decompression with syringo-subarachnoid shunt in three, ventriculo-peritoneal shunt in one, terminal syringostomy in one, and foramen magnum decompression with terminal syringostomy in one. In an average postoperative follow-up period of 3 years and 9 months ranging from one year to 7 years and one month, neurological symptoms and signs improved in 24 out of 28 patients (82%). Some improvement was noted in sensory deficit and motor weakness. In 3 patients, the symptoms did not change. In 3 patients whose symptoms were unchanged, preoperative studies demonstrated atrophy of the spinal cord, in which irreversible changes were shown. The symptoms deteriorated in one patient. In one patient whose symptoms increased 3 months after syringo-subarachnoid shunt, shunt insufficiency due to postoperative adhesive arachnoiditis was responsible for neurological deterioration. The authors propose that syringo-subarachnoid shunt is effective as a surgical procedure for syringomyelia associated with Chiari malformation (type 1) if the patient does not have symptoms due to Chiari malformation or has only mild signs and symptoms which do not require foramen magnum decompression, such as nystagmus or atrophy of sternocleidomastoid muscle.

Syringomyelia-Chiari complex: magnetic resonance imaging and clinical evaluation of surgical treatment

Thirty patients with syringomyelia-Chiari complex who underwent posterior fossa decompression or syringosubarachnoid shunting were studied clinically and by magnetic resonance (MR) imaging to assess the changes in the syrinx and in their clinical picture after surgery. When symptoms of posterior fossa compression were present, posterior fossa decompression was performed; however, when symptoms of posterior fossa compression were absent, the choice of posterior fossa decompression or syringosubarachnoid shunting depended, respectively, on whether the syrinx was narrow or wide on MR imaging. At least 1 year after surgery, subjective improvement or arrest of disease was recorded in 73% of the patients. The present study suggests that: 1) the symptoms attributed to spinal cord damage have no significant relationship to the size of the syrinx on MR images; 2) the surgical techniques employed in this series (posterior fossa decompression or syringosubarachnoid shunt) were equally useful in inducing syrinx collapse; and 3) when posterior fossa decompression is performed, plugging of the obex is not necessary for syrinx collapse.

Management of Scoliosis Due to Syringomyelia in Childhood and Adolescence

To determine the effect of syringomyelia treatment (drainage) on the efficacy of orthotic management and safety of operative management of an associated scoliosis, the records of four boys with scoliosis due to syringomyelia were reviewed. The average follow-up was 8 years. On presentation, all had an abnormal neurologic examination. Each syrinx was treated by laminectomy and insertion of a syringosubarachnoid shunt. After drainage, three of four improved neurologically. Two older patients underwent uneventful posterior spinal fusion with Harrington distraction instrumentation after their drainage procedures. One boy developed kyphosis at the site of his laminectomy. Two young patients, whose curves were initially well controlled with bracing, developed continued curve progression over time. Drainage of the syrinx delayed but did not prevent curve progression in immature patients, but did allow use of distraction instrumentation without complication for operative management of the associated scoliosis.

Hydrosyringomyelia Associated with a Chiari I Malformation in Children and Adolescents

Abstract The clinical presentation, radiological features, and results of surgical treatment were analyzed in 17 cases of hydrosyringomyelia associated with a Chiari malformation, in children and adolescents younger than 20 years of age. The initial symptoms were a skeletal abnormality (71%), such as scoliosis (11 patients) or pes cavus (1 patient), pain or numbness (24%), and motor weakness (6%). Frequently seen signs on admission were sensory deficit (100%), scoliosis (85%), muscle weakness (64%), muscle atrophy (35%), and lower cranial nerve palsy (35%), The characteristic neurological findings were unilateral sensory and motor deficits (65%) with decreased or absent deep tendon reflexes on the same side. The localization of the syrinx on the axial section varied according to the level, even in the same patient. In 11 patients with unilateral sensory disturbances or unilateral sensory and motor deficits, the syrinx was located in the region corresponding to the posterolateral portion on the same side as that of sensory disturbance at the cervical or thoracic level. On the other hand, in 6 patients with bilateral sensory and motor deficits, the syrinx was located in the central portion and extended into the posterolateral portion of the more affected side. A syringosubarachnoid shunt was placed in 16 patients, foramen magnum decompression without closure of the obex was performed in 1 patient, ventriculoperitoneal shunt in 1 patient, terminal syringostomy in 1 patient, and foramen magnum decompression with terminal syringostomy in 1 patient. In 15 of 17 patients (88%), the neurological symptoms improved after an average follow-up of 4 years and 1 month. We think that as a surgical treatment, placement of a syringosubarachnoid shunt is effective.

Hydrosyringomyelia associated with a Chiari I malformation in children and adolescents

The clinical presentation, radiological features, and results of surgical treatment were analyzed in 17 cases of hydrosyringomyelia associated with a Chiari malformation, in children and adolescents younger than 20 years of age. The initial symptoms were a skeletal abnormality (71%), such as scoliosis (11 patients) or pes cavus (1 patient), pain or numbness (24%), and motor weakness (6%). Frequently seen signs on admission were sensory deficit (100%), scoliosis (85%), muscle weakness (64%), muscle atrophy (35%), and lower cranial nerve palsy (35%). The characteristic neurological findings were unilateral sensory and motor deficits (65%) with decreased or absent deep tendon reflexes on the same side. The localization of the syrinx on the axial section varied according to the level, even in the same patient. In 11 patients with unilateral sensory disturbances or unilateral sensory and motor deficits, the syrinx was located in the region corresponding to the posterolateral portion on the same side as that of sensory disturbance at the cervical or thoracic level. On the other hand, in 6 patients with bilateral sensory and motor deficits, the syrinx was located in the central portion and extended into the posterolateral portion of the more affected side. A syringosubarachnoid shunt was placed in 16 patients, foramen magnum decompression without closure of the obex was performed in 1 patient, ventriculoperitoneal shunt in 1 patient, terminal syringostomy in 1 patient, and foramen magnum decompression with terminal syringostomy in 1 patient. In 15 of 17 patients (88%), the neurological symptoms improved after an average follow-up of 4 years and 1 month. We think that as a surgical treatment, placement of a syringosubarachnoid shunt is effective.

Facial Myokymia in Syringobulbia

A patient with a 2-year history of progressive ataxia and tingling in the right hand had prominent facial myokymia. Magnetic resonance imaging revealed syringomyelia and syringobulbia. After successful syringosubarachnoid shunting, the patient died of massive pulmonary embolism. Postmortem examination revealed a syrinx involving the spinal cord and lower half of the medulla; neither the facial nucleus nor facial nerve fibers were directly involved. We hypothesize that interruption of aberrant corticobulbar fibers in the medulla produced disinhibition of a rhythmic neural generator in the facial nucleus.

Surgical treatment of syringomyelia: Favorable results with syringosubarachnoid shunting

The authors review the clinical course of 29 patients who underwent syringosubarachnoid shunting for syringomyelia. Twenty-two patients presented hindbrain-related syringomyelia; seven patients had non-hindbrain-related syringomyelia secondary to trauma (four cases) and to spinal arachnoiditis (three cases). The surgical technique is described in detail. All patients showed postoperative deflation or collapse of the syrinx at follow-up magnetic resonance imaging evaluation. Symptoms stabilized in 17 cases (59%); 9 cases (31%) showed improvement in the neurological function; 3 cases (10%) presented delayed neurological deterioration, probably owing to spinal cord ischemia.

Surgical Treatment of Syringomyelia

The surgical approach to syringomyelia is controversial. In this study, the authors evaluated the results of various operative procedures applied in 31 patients with syringomyelia. Syringomyelia was associated with Chiari malformation in 17 cases, with spinal adhesive arachnoiditis in nine, with trauma in three, and with epidural arachnoid cyst in one. One case was idiopathic. A total of 38 operations were performed. Syringosubarachnoid shunting was applied in 17 patients, syringoperitoneal shunting in 11, terminal syringostomy in three, ventriculoperitoneal shunting in three, lumboperitoneal shunting in two, foramen magnum decompression (suboccipital craniectomy plus upper cervical laminectomy) and terminal syringostomy in one, and foramen magnum decompression with syringosubarachnoid shunting in one. The postoperative follow-up period ranged from 2 to 55 months (average, 26 months). Of the 31 patients, 23 showed neurological improvement, five were unchanged, and three deteriorated. Among the last three, one patient with Chiari malformation developed shunt malfunction due to arachnoiditis after syringosubarachnoid shunting. In two patients with syringomyelia secondary to adhesive arachnoiditis, the spinal cord was damaged by extensive separation of the arachnoid membrane at surgery. On the basis of the results in these 31 cases, the authors conclude that syringosubarachnoid shunting is effective for syringomyelia associated with Chiari malformation if syringomyelia is responsible for the clinical symptoms. Post-traumatic syringomyelia and syringomyelia secondary to adhesive arachnoiditis should be treated by syringoperitoneal shunting. If hydrocephalus is present, ventriculoperitoneal shunting is indicated. Finally, terminal syringostomy is no more effective than syringosubarachnoid or syringoperitoneal shunting.

Shunt Operation for Treatment of Syringomyelia

Although syringomyelia is a well known disease, there is still considerable controversy about the pathogenesis, the indication for surgery and the methods of surgical treatment in syringomyelia. We had the opportunity to study 3 patients with syringomyelia which included posttraumatic syringomyelia, syringomyelia secondary to spianl arachnoiditis, and syringomyelia associated with the Chiari malformation. Two patients were treated with syringoperitoneal shunt and all had good or excellent results with improvement of neurological deficit or cessation of progression. Remaining one patient was treated with syringosubarachnoid shunt and posterior fossa decompression and had excellent result. Follow-up period was very short, but thus favorable result was obtained. Although there are some problems in surgical management of syringomyelia, both syringoperitoneal shunt and syringosubarachnoid shunt are effective therapeutic modalities for many patients with syringomyelia.

Treatment of syringomyelia with a syringosubarachnoid shunt.

The surgical results in 40 patients with syringomyelia, treated with a syringosubarachnoid shunt or other procedures are reviewed. The principal indication for surgery was that of significant neurological deterioration. There were 12 patients with idiopathic syringomyelia without tonsillar ectopia, 12 with an associated Chiari malformation, 11 with post-traumatic syringomyelia and five patients with spinal arachnoiditis. There were 38 syringosubarachnoid shunts performed in 35 patients, and an excellent or good result was achieved in 26 patients (74.3%). In terms of the type of syringomyelia, the best results were obtained in the idiopathic group without tonsillar ectopia and in the post-traumatic group. A short duration of pre-operative symptoms favoured a better outcome, and in our opinion, early surgical treatment is indicated for all patients with neurological deterioration. All eight patients in whom a posterior fossa decompression was performed as the initial surgical procedure required a second operation, either a syringosubarachnoid or syringoperitoneal shunt to achieve neurological improvement or stabilization. Thus, the syringosubarachnoid shunt is an effective therapeutic modality for patients with syringomyelia, particularly for the idiopathic and post-traumatic groups. More than one surgical procedure may be required to achieve cessation of deterioration. Overall, excellent or good results were achieved in 29 (72.5%) of the 40 patients.

Surgical Treatment for Chiari Malformations associated with Congenital Anomalies

Chiari malformations are often associated with congenital anomalies. The authors evaluated several surgical procedures for Chiari malformations associated with basilar impression and/or syringomyelia. Twenty patients with Chiari malformations with and without congenital anomalies were treated by various surgical procedures. Associated anomalies were atlantoaxial dislocation in one, basilar impression in eight, and syringomyelia in 11. There were 11 males and nine females, ranging in age from 6 to 63 years. Nine patients were treated by foramen magnum decompression (suboccipital craniectomy and upper cervical laminectomy), one by foramen magnum decompression combined with terminal syringostomy, one by anterior decompression via the transoral approach, and nine by syringosubarachnoid shunting. The period of follow-up ranged from 5 months to 21 years (mean, 7 years). Seventeen of the 20 patients showed neurological improvement, one was unchanged, and two deteriorated. One of the patients who deteriorated had undergone syringosubarachnoid shunting, and the shunt malfunctioned because of arachnoiditis. A patient with basilar impression died of respiratory failure after suboccipital craniectomy and upper cervical laminectomy. On the basis of their results, the authors recommend posterior decompression for patients with Chiari malformations alone. If a foramen magnum lesion is responsible for the neurological manifestations and the clivoaxial angle is narrow in Chiari malformations associated with basilar impression and/or syringomyelia, anterior decompression with fusion should be performed. If the clivoaxial angle is within normal limits, the authors perform posterior decompression. Syringosubarachnoid shunting appears effective in patients in whom syringomyelia is the main cause of neurological symptoms.

MRI measurement of syrinx size before and after operation.

When patients with syringomyelia fail to improve after operation, factors such as incomplete cyst decompression or type of operation are often implicated. MRI has been used to confirm adequate syrinx decompression post-operatively and to compare the degree of collapse with the type of operation. Foramen magnum decompression was at least as effective in reducing cyst size as syringo-subarachnoid shunting. MRI may also provide a better classification of syringomyelia.