Management of cerebellar ptosis following craniovertebral decompression for Chiari I malformation.

OBJECT: In this report the authors review their experience in the treatment of seven patients with symptomatic cerebellar ptosis following craniovertebral decompression (CVD) for Chiari I malformation. METHODS: The mean age of the patients was 37 years and the average amount of time between the initial suboccipital craniectomy and evaluation for cerebellar ptosis was 6.8 years. Five patients presented primarily with intractable headache and the remaining two patients with neurological deficits caused by recurrent syringomyelia. Three different surgical modalities were used to treat these patients: ventriculoperitoneal shunt placement (one patient), syringoperitoneal shunt placement (two patients), and partial suboccipital cranioplasty with or without intradural exploration (four patients). The mean follow-up period was 51 months. The three patients who underwent shunt placement procedures experienced poor results, with no evidence of symptom relief and continued neurological deterioration. In contrast, all four patients who underwent cranioplasty experienced good or excellent clinical outcomes. Postoperative magnetic resonance imaging studies revealed a reduction in the size of the syrinx cavity in patients who simultaneously underwent intradural exploration. CONCLUSIONS: The emergence of symptomatic cerebellar ptosis following CVD for Chiari I malformation is primarily caused when the suboccipital craniectomy is too large for the specific patient. The cerebellar ptosis usually presents with severe headache and/or neurological deficit due to persistent or recurrent syringomyelia. Partial suboccipital cranioplasty, with or without intradural exploration, is effective in treating this condition.

Treatment of severe retromastoid pain secondary to C1-2 arthrosis by using cervical fusion.

OBJECT: In this report the authors review their 5-year experience in the diagnosis and management of nine patients with severe retromastoid pain secondary to C 1-2 arthrosis. Patients with symptomatic joints unresponsive to nonoperative therapy underwent cervical fusion procedures. METHODS: The mean age of the patients was 71 years, and the onset of prior symptoms ranged from 6 months to 18 years. All patients suffered similar discrete nonneuropathic pain without radicular symptoms ipsilateral to the diseased facet joint. Four patients experienced relief from pain with the use of nonoperative therapy. Five patients continued to experience intractable pain and underwent C1-2 fusion. The follow-up period ranged from 6 to 26 months. The cervical fusion procedure was successful in treating the retromastoid pain in all patients. In patients who underwent surgery, complete relief of pain was demonstrated in four and significantly reduced in the fifth. CONCLUSIONS: The authors have drawn several conclusions. First, C1-2 arthrosis has a rather unique presentation and is a potential cause of upper posterior neck and head pain predominantly in elderly patients. Second, nonoperative management significantly improved the pain in nearly half of their patients and should be the first line of treatment. Last, C1-2 fusion was successful in treating the pain in patients in whom nonoperative management had failed to resolve symptoms.

Anterior cervical foraminotomy for unilateral radicular disease.

STUDY DESIGN: A clinical series of patients with unilateral radiculopathy treated with the anterior cervical foraminotomy procedure. OBJECTIVE: To establish procedural techniques and clinical and radiologic outcomes for the anterior cervical foraminotomy procedure. SUMMARY OF BACKGROUND DATA: Cervical radiculopathy is typically caused by unilateral disc herniation or uncovertebral osteophytes that compress the ventral aspect of the nerve. Direct removal of a cervical lesion causing radicular symptoms without concomitant fusion seems to be an ideal treatment in selected patients. The indications for an anterior cervical neural foraminotomy are limited to unilateral radicular symptoms at one or two levels, with minimal neck pain. METHODS: Twenty-one patients were treated with the anterior cervical neural foraminotomy procedure during a 3-year period with follow-up from 6 to 36 months. There were 13 men and 8 women (age range, 27-58 years). Fourteen patients had symptomatic soft disc herniation, and 7 had uncovertebral osteophytes confirmed by magnetic resonance imaging and/or myelogram and computed tomography. Sixteen patients had a single anterior cervical neural foraminotomy, and 5 had procedures at adjacent levels. RESULTS: Nineteen patients (91%) had improved or resolved radicular symptoms, and 2 (9%) had persistent radicular symptoms necessitating further surgery (one two-level anterior cervical neural discectomy and fusion and one posterior foraminal decompression). CONCLUSIONS: Patients treated with the anterior cervical neural foraminotomy procedure have equivalent or better outcomes than those who undergo current cervical procedures. It appears to be a good alternative procedure for carefully selected patients with unilateral cervical radiculopathy and avoids a fusion of the disc space.

Primary spinal syringomyelia: a personal perspective.

In this paper the author summarizes currently available surgical approaches to spinal syringomyelia that is unrelated to Chiari I malformation or hindbrain descent. Primary spinal syringomyelia is most commonly associated with spinal trauma but is also encountered as a sequela to intradural inflammatory processes (infections or chemical), as a delayed response to surgical procedures, and in association with intra- and extradural neoplasms as well as disc protrusions. The advantages of placing a shunt are its technical simplicity and immediate reduction of syrinx size; its major disadvantages are the high rate of failure observed in long-term follow up and the difficulty in applying this technique in septated cysts. Expansion of the subarachnoid space with resection of scars has better long-term results. Patients in whom a syrinx cavity has caused a kyphotic spinal deformity may need to undergo a procedure in which the kyphotic deformity is corrected to expand the subarachnoid space. Cyst obliteration is an experimental approach that cannot be evaluated at the present time.

Treatment of posttraumatic syringomyelia with extradural decompressive surgery.

The authors review the management of five patients with posttraumatic syringomyelia (PTS) associated with an uncorrected spinal deformity. Patients with evidence of progressive neurological deterioration underwent ventral spinal decompressive surgery. The mean patient age at the time of injury was 39 years, and the time between injury and the diagnosis of PTS ranged from 2 to 22 years. Mechanisms of injury consisted of fracture/subluxations in three patients and burst fractures in two. All patients experienced delayed neurological deterioration consistent with PTS. Magnetic resonance imaging revealed ventral deformities, and the spinal canal stenosis ranged from 20 to 50% (mean 39%). All patients underwent ventral epidural spinal decompressive surgery to correct the bone deformity and restore the spinal canal. The mean follow-up period was 38 months. The decompressive intervention was initially successful in treating the neurological deterioration in all patients. Symptoms resolved completely in four patients, and the other experienced neurological improvement. Postoperative magnetic resonance imaging revealed a reduction in the size of syrinx cavity in the patients whose symptoms resolved and no change in the remaining patient. Two patients required a subsequent second-stage posterior intradural exploration and duraplasty for recurrence of symptoms and/or syrinx. Posttraumatic spinal deformity may cause spinal canal stenosis and alter subarachnoid cerebrospinal fluid (CSF) flow in certain patients. Ventral epidural spinal decompressive surgery may result in neurological improvement and a reduction of the syrinx cavity, avoiding the need for placement of a shunt or other intradural procedures. However, some patients will also require reconstruction of the posterior subarachnoid space with duraplasty if the ventral decompressive procedure achieves only partial restoration of the subarachnoid CSF flow.

Syringomyelia persistence after Chiari decompression as a result of pseudomeningocele formation: implications for syrinx pathogenesis: report of three cases.

OBJECTIVE AND IMPORTANCE: We present the cases of three patients in whom pseudomeningocele (PSM) formations after posterior fossa decompression of hindbrain herniations (Chiari I malformations) were associated with persistence of syringomyelia. The physiological importance of correcting this complication has not been previously described. CLINICAL PRESENTATION: We identified three patients who developed suboccipital PSMs after undergoing posterior fossa decompression for hindbrain herniations and syringomyelia. All three patients experienced persistence of their symptoms and their syringomyelia, despite adequate posterior fossa decompression. TECHNIQUE: Subsequent exploration revealed cerebrospinal fluid leaking either from the dural suture line (one patient) or from perforations found within the bed of a polyglactin mesh dural graft (two patients). Correction of the PSM resulted in resolution of both the syringomyelia and the symptoms in all three patients. DISCUSSION: The persistence of syringomyelia in the presence of a PSM may be the result of dissipation of the cerebrospinal fluid systolic pressure wave into the distensible PSM cavity. This phenomenon suggests that the cerebrospinal fluid pressure exerted on the spinal cord surface favors resolution of the syrinx cavity.

A critical appraisal of syrinx cavity shunting procedures.

OBJECT: This study was conducted to evaluate the results of shunting procedures for syringomyelia. METHODS: In a follow-up analysis of 42 patients in whom shunts were placed in syringomyelic cavities, the authors have demonstrated that 21 (50%) developed recurrent cyst expansion indicative of shunt failure. Problems were encountered in patients with syringomyelia resulting from hindbrain herniation, spinal trauma, or inflammatory processes. A low-pressure cerebrospinal fluid state occurred in two of 18 patients; infection was also rare (one of 18 patients), but both are potentially devastating complications of shunt procedures. Shunt obstruction, the most common problem, was encountered in 18 patients; spinal cord tethering, seen in three cases, may account for situations in which the patient gradually deteriorated neurologically, despite a functioning shunt. CONCLUSIONS: Placement of all types of shunts (subarachnoid, syringoperitoneal, and syringopleural) may be followed by significant morbidity requiring one or more additional surgical procedures.

Treatment of syringomyelia associated with arachnoid scarring caused by arachnoiditis or trauma.

The authors conducted a retrospective study of 107 patients treated for syringomyelia associated with arachnoid scarring between 1976 and 1995 at the Departments of Neurosurgery at the Nordstadt Hospital in Hannover, Germany, and the University of California in Los Angeles, California. Twenty-nine patients have not been surgically treated to date because of their stable neurological status. Seventy-eight patients with progressive neurological deficits underwent a total of 121 surgical procedures and were followed for a mean period of 32 (+/- 37) months. All patients demonstrated arachnoid scarring at a level close to the syrinx. In 52 patients the arachnoid scarring was related to spinal trauma, whereas 55 had no history of trauma and developed arachnoid scarring was a result of an inflammatory reaction. Of these, 15 patients had undergone intradural surgery, eight had suffered from spinal meningitis, three had undergone peridural anesthesia, and one each presented with a history of osteomyelitis, spondylodiscitis, and subarachnoid hemorrhage. No obvious cause for the inflammatory reaction resulting in arachnoid scarring could be ascertained for the remaining 26 patients. The postoperative neurological outcome correlated with the severity of arachnoid pathology and the type of surgery performed. Shunting of the syrinx to the subarachnoid, pleural, or peritoneal cavity was associated with recurrence rates of 92% and 100% for focal and extensive scarring, respectively. Successful long-term management of the syrinx required microsurgical dissection of the arachnoid scar and decompression of the subarachnoid space with a fascia lata graft. This operation stabilized the preoperative progressive neurological course in 83% of patients with a focal arachnoid scar. For patients with extensive arachnoid scarring over multiple spinal levels or after previous surgery, clinical stabilization was achieved in only 17% with this technique.

Thoracic spinal Pantopaque cyst and associated syrinx resulting in progressive spastic paraparesis: case report.

OBJECTIVE AND IMPORTANCE: We describe a unique presentation of a thoracic spinal Pantopaque cyst. Although Pantopaque is no longer used, sequelae of its long-term use may continue to surface. CLINICAL PRESENTATION: Our patient presented to the emergency room with 4 months of progressive lower extremity numbness, spasticity, and incontinence and a 2-day history of left upper extremity dysesthesias. Magnetic resonance imaging at admission revealed a C7-T10 syrinx and an intrathecal extramedullary mass to the right of the spinal cord at T10-T11. INTERVENTION: Radiographic evidence led to the initial diagnosis of hemangioblastoma. The results of a critical analysis of the preoperative studies caused us to suspect a Pantopaque cyst. This suspicion was confirmed at the time of surgery, when a cyst filled with contrast medium was revealed. T9-T11 laminectomies were performed, allowing for a 5-cm dural opening. The cyst was aspirated and excised, and then the syrinx was decompressed. CONCLUSION: Our patient experienced significant sensory and motor improvement postoperatively. We present a previously undescribed complication of one of the most commonly used contrast media, Pantopaque. Despite its replacement with newer agents, it may continue to play a significant role in the pathological presentation of patients in whom it was previously used.

The surgical treatment of Chiari I malformation.

A retrospective study was undertaken on 133 patients with a Chiari I malformation treated within the last 16 years at the Departments of Neurosurgery at the Nordstadt Hospital Hannover, Germany, and the University of California, Los Angeles, U.S.A. Ninety-seven patients presented with symptoms related to accompanying syringomyelia and 4 with associated syringobulbia. They underwent 149 surgical procedures and were followed for a mean of 39 +/- 52 months. A decompression at the foramen magnum was performed in 124 patients, while 22 of those with syringomyelia were treated by shunting (7 syringosubarachnoid shunts, 15 syringoperitoneal or -pleural shunts), and 3 by ventriculoperitoneal shunts for hydrocephalus. Except for ventriculoperitoneal shunting, at least a short-term decrease in size of an associated syrinx was observed for all procedures in the majority of cases. However, no long-term benefit was observed for syrinx shunting operations. The best clinical long-term results were obtained with decompression of the foramen magnum in patients with (86% free of a clinical recurrence) and without syringomyelia (77% free of a clinical recurrence). We advise against syrinx shunting, a large craniectomy, and obex plugging which are associated with higher recurrence rates. Instead, surgery should consist of a small craniectomy, opening of the dura, archnoid dissection to establish normal cerebrospinal fluid (CSF) outflow from the 4th ventricle, and a fascia lata dural graft.

Posterior fossa volume and response to suboccipital decompression in patients with Chiari I malformation.

Smaller posterior fossa (PF) volume has been suggested to be one of the mechanisms responsible for tonsillar herniation through the foramen magnum in patients with Chiari I malformation (CM I). Although previous radiological analyses of the cranial anatomy have suggested a smaller PF volume in patients with CM I, the relationship of the PF volume to decompressive surgery has not been reported. We have measured the ratio of PF volume to supratentorial volume (PF ratio [PFR]) in 20 patients with CM I and 20 control patients by retrospectively studying their magnetic resonance images with a computerized image analyzer. The mean PFR in patients with CM I (with or without syringomyelia) was significantly smaller than for those in the control group (15.6 +/- 1.9 versus 17.5 +/- 1.2, P = 0.0008). Although PFR did not correlate with the extent of tonsillar herniation in patients with CM I, it did directly correlate with their age, i.e., younger patients with CM I (but not control patients) had smaller PFRs. All but three patients responded both clinically and radiographically to decompressive surgery. Those patients who did not benefit from surgical intervention had normal PFRs. We conclude that: 1) PFRs are smaller in most patients with CM I; 2) a smaller PF may be a primary cause of tonsillar herniation; 3) patients with CM I who have smaller PFRs tend to develop symptoms earlier than those with normal values; 4) patients with smaller PFRs tend to respond better to suboccipital decompression.

Posterolateral cervical or thoracic approach with spinal cord rotation for vascular malformations or tumors of the ventrolateral spinal cord.

This report describes a technique for exposing the ventrolateral quadrant of the spinal cord through an extended posterolateral approach that can be used in both cervical and thoracic regions. The surgical technique includes the following: 1) a midline skin incision with a transverse extension at the level of pathology; 2) unilateral division and retraction of the paraspinous muscles; 3) laminectomy and unilateral removal of facets and pedicles; 4) dural incision over the dorsal root entry zone; 5) multilevel division of the ipsilateral dentate ligaments; and 6) elevation and rotation of the spinal cord with dentate traction stiches. This technique provides exposure of the ventral root entry zone, the ipsilateral half of the ventral surface of the cord, and the anterior spinal artery. The surface of the spinal cord beyond the anterior spinal artery is not seen. This approach has been used for the treatment of seven ventrolateral spinal cord lesions: five spinal arteriovenous malformations (two Type II, one Type III, two Type IV), one hemangioblastoma, and one cavernous angioma. All the lesions were completely excised. Two patients had mild new neurological deficit after surgery, and one adolescent developed mild asymptomatic thoracic kyphosis, but no other spinal instability was observed over a follow-up period of 1 to 4 years. This operative approach provides significant advantages for ventrolateral perimedullary or intramedullary lesions of the cervical or thoracic spinal cord.

Ependymoma of the cauda equina region: diagnosis, treatment, and outcome in 15 patients.

New diagnostic imaging techniques make possible a reappraisal of current diagnostic, therapeutic, and management strategies for certain rare lesions of the central nervous system. With this in mind, we have reviewed our experience with ependymoma of the filum terminale and cauda equina region. Fifteen patients with this tumor have been treated since 1955. Typical presentations included pain, lower extremity weakness, and, occasionally, bladder dysfunction. Delays in arriving at the proper diagnosis have been the rule; however, we have noted a substantial increase in the number of these tumors referred to us since the advent of magnetic resonance imaging. Treatment includes surgical resection to the extent consistent with preservation of neurological function; postoperative irradiation appears to be of benefit in controlling recurrence except in those patients whose well-circumscribed tumors have been removed completely. Presence of urinary difficulties at the time of diagnosis is a relatively poor prognostic sign, and a more liberal use of magnetic resonance imaging in cases of persistent or recurrent low back and radicular pain unresponsive to conservative therapy may help to achieve earlier diagnosis. Because of the possibility of late recurrence, prolonged follow-up is mandatory for all patients, and magnetic resonance imaging is the diagnostic tool of choice.

Myxopapillary ependymoma with extensive sacral destruction: CT and MR findings.

There have been few reports documenting primary myxopapillary ependymomas in the sacrococcygeal region that result in extensive involvement of the sacrum. We present a 21-year-old man whose CT and MR findings showed massive bony destruction of the sacrum and a large lobulated soft tissue mass. Myxopapillary ependymoma should be included along with giant cell tumor, chordoma, and aneurysmal bone cyst in the differential diagnosis of a destructive osteolytic sacral lesion.

MR of hemorrhagic acoustic neuromas.

The magnetic resonance (MR) appearance of hemorrhagic acoustic neuromas has not previously been reported. Four patients with surgically proven acoustic neuromas containing spontaneous hemorrhage were preoperatively evaluated with MR imaging. All patients presented with new onset of symptoms and three had subarachnoid hemorrhage. Signal changes on T1- and T2-weighted spin echo sequences were characteristic for acute, subacute and chronic intraparenchymal hemorrhage. Recognition of hemorrhagic changes on MR is important since more rapid surgical intervention is required in this patient subgroup.

Surgical decompressive procedures for cervical spondylotic myelopathy. A study using magnetic resonance imaging.

Twenty-two patients who underwent a surgical decompressive procedure for cervical spondylotic myelopathy were studied with magnetic resonance imaging to evaluate the effectiveness of their decompressive procedures. Twelve patients were judged as adequately decompressed by magnetic resonance imaging criteria. Ten patients exhibited evidence of residual cord indentation. This along with cord atrophy, gliosis, and abnormal spine curvature presumably contributed to residual deficit in several patients. One patient underwent a second decompressive procedure for residual cord indentation, which subsequently improved, as seen on his second postoperative magnetic resonance image. Magnetic resonance imaging was useful in distinguishing mechanical problems from intrinsic cord damage or atrophy. Magnetic resonance imaging should be used after operation in patients with residual deficit to detect patients who may be considered for a second decompressive procedure.

Grisel's syndrome. Cervical spine clinical, pathologic, and neurologic manifestations.

Grisel's syndrome involves the subluxation of the atlantoaxial joint from inflammatory ligamentous laxity following an infectious process. Even though it was first described in 1830, it is a rare disease usually affecting children, but infrequent adult cases do occur. Patients generally seek treatment for progressive unrelenting throat and neck pain followed by torticollis and subluxation. Neurologic complications occur in approximately 15% of cases and can range from radiculopathy to myelopathy and even death. Principles of management include bacteriologic cure and correction of bony deformity and neurologic protection. The authors present two adult patients with Grisel's syndrome. The first illustrates the permanent spinal deformity that can occur if the disease remains unrecognized for a prolonged period of time. The second case demonstrates a delayed neurologic complication in an adult who had Grisel's syndrome in childhood. It is hoped that these two examples, together with a detailed discussion of the literature, will inform physicians of an unusual but important condition to be considered in the differential diagnosis of any patient complaining of neck pain.

Posttraumatic syringomyelia.

Posttraumatic syringomyelia is becoming increasingly recognized as a sequel to major and minor spinal cord injury, paralleling the development and widespread availability of magnetic resonance imaging as a diagnostic modality for evaluating possible spinal pathologic lesions. Delayed, subacute, or progressive neurologic deterioration in victims of traumatic spinal injury with "fixed deficits" should raise the suspicion of posttraumatic syringomyelia. Alternatively, it may present as sensory or motor complaints occurring on a delayed basis after minor spinal trauma causing no initial neurologic impairment. At our institution, we have treated six of eight patients with this condition by shunting fluid from the intramedullary cyst to the peritoneal cavity by means of a simple valveless shunt, resulting in sustained neurologic improvement in five patients.

Analysis of cervical spine curvature in patients with cervical spondylosis.

Computer-aided design techniques were used to analyze the degree of spinal curvature shown on cervical spine radiograms of 28 patients. On films standardized as to size, a geometrical chord was constructed from the 2nd to the 7th cervical vertebrae (C2 to C7), and an arc was drawn along the posterior margin of the vertebrae. The resulting area was used as an index of curvature, and the spinal canal diameter was measured. Severity of myelopathy as well as clinical improvement was related to the geometrical data. There was no clear correlation between severity of the preoperative myelopathy and degree of curvature. Severe myelopathy was seen in association with straight, lordotic, and hyperlordotic spines. Neck pain was most severe in patients with reversed cervical curvature. The degree of curvature, however, seems to relate to the postoperative clinical outcome. Patients with relatively normal curvature showed the greatest improvement in symptoms and signs. Postoperative magnetic resonance scanning confirms that posterior migration of the spinal cord after laminectomy may be inadequate to clear osteophytes in patients with straightened or reversed curvature of the cervical spine. Spinal geometry should be considered in the selection of the best surgical procedure and the extent of laminectomy for patients with spondylotic myelopathy. Significant abnormalities of spinal curvature may account for some instances of poor outcome after laminectomy.

Chiari I malformation with syringomyelia. Evaluation of surgical therapy by magnetic resonance imaging.

Five patients with a Chiari I-syringomyelia complex of adult onset were evaluated by magnetic resonance (MR) imaging. All patients underwent suboccipital craniotomy with upper cervical (C-1 and part of C-2) laminectomy, arachnoid retraction, and duraplasty. Postoperative MR studies of four patients disclosed collapse of the syringomyelic cavity, even when the cavity extended into the thoracic region. This appeared to be a progressive process taking place over several weeks. Operative complications are noted and physiological implications are discussed.