Cervical myelopathy caused by median disc herniation: analysis of the complications following anterior discectomy with and without Fusion Report of 90 cases

Between 1980 and 1992 about 400 patients underwent anterior cervical discectomy with or without intersomatic fusion at the Department of Neurosurgery of CTO Hospital (Rome) and Nuovo Pellegrini Hospital (Naples). Among them 90 patients were selected (50 from CTO and 40 from Nuovo Pellegrini Hospital). Clinical evaluation of postoperative results were assessed according to Odom's grading system and postoperative complications were discussed. No difference was observed in patients who underwent anterior cervical discectomy with and without fusion; however, postoperative complications were frequently observed in patients who underwent fusion. In conclusion, we consider the anterior microdiscectomy as the treatment of choice for the removal of soft disc herniations with or without osteophytosis even at two level disc. If cervical myelopathy is expression of one or more disc herniations, maybe calcified and associated with marked osteoarthrosic degenerative phenomena, we favour the evacuation of the herniated disc and the removal of osteophytes with Cloward's or Smith-Robinson's techniques.

Myelopathy due to hypoplasia of the atlas. A case report

The authors report a 73-year-old woman who had spinal cord compression develop because of hypoplasia of the atlas associated with a retroodontoid pseudotumor diagnosed by magnetic resonance imaging. Radiographs of the cervical spine showed narrowing of the spinal canal at the level of the atlas and severe osteoarthrosis of the atlantoaxial joint without atlantoaxial subluxation. A remarkable neurologic recovery followed decompressive laminectomy of the atlas with posterior occipitocervical fusion. Postoperative magnetic resonance imaging showed significant reduction of the retroodontoid pseudotumor by fusion alone. The magnetic resonance imaging finding of spontaneous reduction of retroodontoid pseudotumor after posterior fusion argues against a need for transoral removal, which has a significant complication rate.

Tethered thoracic cord resulting from spinal cord herniation

Tethered cord syndrome (TCS) usually involves tethering of the lower cord at the conus medullaris from dural abnormalities, but may occur after spinal cord herniation. A tethered thoracic spinal cord is rare. We present an unusual case of a 30-year-old woman with a history of myelopathy presumed to be secondary to T6 cord compression resulting from T6-T8 arachnoid cyst. She continued to deteriorate after partial excision of the cyst. Repeat magnetic resonance imaging suggested recurrence of the presumed arachnoid cyst with cord compression and showed tethering at T6-T8. Surgical exploration revealed myelocele with cord herniation through the anterior thoracic dura. Pathologic diagnosis showed neural tissue with gliosis. After physical therapy treatments, the patient had increased lower extremity strength, ambulated with a cane, and regained some bladder control. Progressive myelopathy may represent tethering of the cord resulting from cord herniation. Early recognition of TCS, even in patients with minimal neurologic deficits, could prevent progressive disability.

Gabexate mesilate, a synthetic protease inhibitor, prevents compression-induced spinal cord injury by inhibiting activation of leukocytes in rats

OBJECTIVE

Gabexate mesilate is a synthetic protease inhibitor capable of inhibiting both coagulation and cytokine production by monocytes. To investigate whether gabexate mesilate is useful for the prevention of posttraumatic spinal cord injury, we examined its effect on compression trauma-induced spinal cord injury in rats.

DESIGN

Prospective, randomized, blinded, controlled study.

SETTING

Research laboratory at a university medical center.

SUBJECTS

Male Wistar rats weighing 300 to 350 g.

INTERVENTIONS

Spinal cord injury was induced by applying a 20-g weight extradurally to the spinal cord at the level of the 12th thoracic vertebra for 20 mins. Spinal cord injury was evaluated by assessing the motor function of the rats 24 hrs posttrauma. The accumulation of leukocytes and histologic changes in the injured spinal cord tissue also were examined. Rats received gabexate mesilate (10 or 20 mg/kg i.p.) 30 mins before or after the compressive trauma. The effects of heparin or an inactive derivative of activated factor X (a selective inhibitor of thrombin generation) on compressive trauma-induced spinal cord injury also were examined. Leukocytopenia was induced by the administration of nitrogen mustard.

MEASUREMENTS AND MAIN RESULTS

The motor disturbances observed following traumatic spinal cord compression, evaluated by Tarlov's score, and the accumulation of leukocytes in the injured tissue, evaluated by measuring tissue myeloperoxidase activity, were markedly reduced by leukocyte depletion induced by nitrogen mustard and by pre- or posttreatment of animals with gabexate mesilate. Neither heparin nor the inactive derivative of activated factor X prevented the motor disturbances and the accumulation of leukocytes. Histologic examination demonstrated that intramedullary hemorrhages observed 24 hrs after trauma at the 12th thoracic vertebra were significantly attenuated by nitrogen mustard-induced leukocytopenia and the administration of gabexate mesilate.

CONCLUSIONS

The compression trauma-induced spinal cord injury demonstrated by this model was mainly mediated by leukocytes. Gabexate mesilate prevented spinal cord injury not by inhibiting coagulation, but by inhibiting the activation of leukocytes.

Spinal canal compromise in Proteus syndrome: case report and review of the literature

A 24-year-old Vietnamese man with Proteus syndrome presented to the emergency department with progressive paraplegia and underwent urgent operative decompression of an angiolipomatous mass compressing the spinal cord. The associated spinal deformity and difficulty in imaging the mass, together with the paucity of discussion regarding the spinal cord sequelae of this rare syndrome in the literature, made this an extremely challenging case. Spinal cord compromise in patients with Proteus syndrome can result from either infiltration of the spinal canal by an angiolipomatous mass or canal narrowing as a result of vertebral hypertrophy. Regardless of the cause, the prognosis for neural recovery remains poor.

Pathogenesis of cervical spondylotic myelopathy

OBJECTIVE

To determine whether either of two mechanical theories predicts the topographic pattern of neuropathology in cervical spondylotic myelopathy (CSM). The compression theory states that the spinal cord is compressed between a spondylotic bar anteriorly and the ligamenta flava posteriorly. The dentate tension theory states that the spinal cord is pulled laterally by the dentate ligaments, which are tensed by an anterior spondylotic bar.

METHODS

The spinal cord cross section, at the level of a spondylotic bar, is modelled as a circular disc subject to forces applied at its circumference. These forces differ for the two theories. From the pattern of forces at the circumference the distribution of shear stresses in the interior of the disc-that is, over the transverse section of the spinal cord-is calculated. With the assumption that highly stressed areas are most subject to damage, the stress pattern predicted by each theory can be compared to the topographic neuropathology of CSM.

RESULTS

The predicted stress pattern of the dentate tension theory corresponds to the reported neuropathology, whereas the predicted stress pattern of the compression theory does not.

CONCLUSIONS

The results strongly favour the theory that CSM is caused by tensile stresses transmitted to the spinal cord from the dura via the dentate ligaments. A spondylotic bar can increase dentate tension by displacing the spinal cord dorsally, while the dural attachments of the dentate, anchored by the dural root sleeves and dural ligaments, are displaced less. The spondylotic bar may also increase dentate tension by interfering locally with dural stretch during neck flexion, the resultant increase in dural stress being transmitted to the spinal cord via the dentate ligaments. Flexion of the neck increases dural tension and should be avoided in the conservative treatment of CSM. Both anterior and posterior extradural surgical operations can diminish dentate tension, which may explain their usefulness in CSM. The generality of these results must be tempered by the simplifying assumptions required for the mathematical model.

Imaging findings of spontaneous spinal epidural hematoma

The imaging studies of 12 patients with spontaneous spinal epidural hematomas (SSEHs) who were treated from 1987 to 1995 at Chang Gung Memorial Hospital were retrospectively analyzed. The advantages and disadvantages of myelography, computed tomographic myelography (CTM) and magnetic resonance imaging (MRI) in diagnosing SSEH were evaluated. We found that in subacute and chronic stages of SSEH, MRI was the diagnostic choice because of its pathognomonic magnetic resonance signal changes. However, in the first 24 hours of SSEH, the MRI signal changes of hematomas were confused with those of epidural metastatic tumors or abscesses. In this situation, enhancement was not an absolute sign to rule out hematomas, because gadolinium enhancement of a hematoma did occur in one of our patients. CTM was helpful in this stage because a hyperdense epidural mass was always noted. In conclusion, we found that MRI offers a noninvasive and specific diagnosis of SSEH, though it has some pitfalls in the first 24 hours of SSEH. CTM with sagittal reformations also provides a specific diagnosis, especially when a hyperdense mass is seen. By combining these diagnostic imaging modalities and clinical manifestations, an early diagnosis of SSEH is possible.

Coexisting peripheral nerve and cervical cord compression

STUDY DESIGN

The authors investigated the clinical usefulness of recording motor evoked potentials after transcranial magnetic stimulation in coexisting peripheral nerve and cervical cord lesions.

OBJECTIVE

To show that the measurement of central motor conduction time from the abductor policis brevis and the abductor digiti minimi can be used as a good screening method for double lesions involving peripheral nerves and the cervical cord.

SUMMARY OF BACKGROUND DATA

Transcranial magnetic stimulation has been used in the diagnosis of compressive cervical myelopathy. This technique could be useful in the assessment of patients with an entrapment neuropathy and cervical myelopathy.

METHODS

Motor evoked potentials after transcranial magnetic stimulation, compound muscle action potentials, and F waves after supramaximal peripheral nerve stimulation were recorded from the abductor policis brevis and the abductor digiti minimi. The central motor conduction time was calculated by subtracting the peripheral conduction time from the motor evoked potentials latency.

RESULTS

Ten patients with coexisting peripheral nerve and cervical cord lesions were evaluated. Two patients did not show satisfactory improvement after the decompression of the entrapment lesions, and six patients had hyperreflexia of lower limbs. In seven of these patients, the central motor conduction time was prolonged an average of 2.5 standard deviation of the normal value. The remaining two patients had spinal cord compression due to the ossification of the posterior longitudinal ligament. The spinal cord compression was demonstrated by magnetic resonance imaging, but the central motor conduction time was normal. Subjective symptoms improved in these two patients after decompressive surgery at the entrapment site alone.

CONCLUSIONS

Measurement of the central motor conduction time using motor evoked potentials is an ideal diagnostic approach for patients with coexisting entrapment neuropathy and cervical cord compression.

Cervical myelo-radiculopathy in athetoid cerebral palsy

Cervical myelopathy complicating athetoid cerebral palsy has not been adequately highlighted in the literature. We report two cases of patients with athetoid cerebral palsy and long histories of involuntary movements who developed cervical myelo-radiculopathy. Dystonic athetoid neck movements may cause excessive axial neck rotation as well as flexion and extension movements of the spine. These repetitive exaggerated movements may result in early degenerative changes of the vertebrae which may enhance the myelo-radiculopathy. The two patients were treated with combined anterior and posterior fusion with satisfactory results. They were bedridden preoperatively but have since started walking with or without a cane. We conclude that combined anterior and posterior fusion is the treatment of choice for severe myelopathy complicating athetoid cerebral palsy.

Neurological impairment during long-term intrathecal infusion of bupivacaine in cancer patients: a sign of spinal cord compression

Adequate pain relief in patients with far advanced cancer sometimes requires intrathecal (IT) administration of a combination of opioids and local anesthetics. Tumor progression as well as the IT administration of local anesthetics can lead to neurologic dysfunction during treatment. Five patients showed symptoms of compression of the cauda equina or spinal cord shortly after the start of combined IT administration of morphine and bupivacaine in a dosage usually not associated with neurologic symptoms. Unexpectedly, neurologic evaluation suggested compression of the cauda equina and spinal cord, which was confirmed radiographically. Manifestation of new neurologic symptoms during low dose bupivacaine infusion intrathecally might therefore be an early indicator of space-occupying processes within the spinal canal in cancer patients.

Sleep-related periodic leg movements associated with spinal cord lesions

We describe three patients who developed progressive paraparesis and sleep-related periodic leg movements (SRPLM) associated with thoracic spinal cord lesions; one patient had a schwannoma and two had intramedullary lesions. The patients showed periodic repetitive involuntary movements involving one or both lower limbs. The involuntary movements consisted of a single rapid dorsiflexion of the great toe or ankle, two to four repetitive dorsiflexions of the toes and ankle, and a mixture of repetitive jerks and prolonged spasms causing flexion of the hip and knee and dorsiflexion of the ankle and toes. In the patient with a schwannoma, paraparesis and SRPLM improved completely after surgical removal of the mass lesion. In one patient the SRPLM associated with an intramedullary lesion improved markedly after levodopa treatment. We suspect that thoracic spinal lesions partially disinhibit the lumbosacral generator. Such disinhibition seems to be enhanced by the activation of the neuronal systems related to periodic somatic and vegetative phenomena during sleep.

Clinical outcome in metastatic spinal cord compression. A prospective study of 153 patients

BACKGROUND

Despite many reports on metastatic spinal cord compression, only very few prospective studies of the clinical outcome of spinal cord compression have been carried out.

METHODS

153 consecutive patients with a known malignant solid tumor and a myelographically verified diagnosis of spinal cord compression were followed with regular neurological examination.

RESULTS

At time of diagnosis 79 patients were walking, while the remaining were bedridden. In total 21 of the 74 initially non-walking patients began walking after therapy. There was a need for urinary catheter in 57 (37%) patients at the time of diagnosis. During follow-up, 10 of 57 patients (18%) dispensed with the catheter. A total of 116 patients experienced radicular pain at the time of diagnosis, while in 95 of 116 patients (83%) the pain disappeared after therapy.

CONCLUSION

the present study confirms, that early diagnosis, i.e., while the patients are still ambulatory, is most important, but the prognosis for recovery of ambulatory function is not as pessimistic as earlier described. In addition the results indicate that supplementary systemic therapy, when available, may have a positive influence on recovery.

Lordotic alignment and posterior migration of the spinal cord following en bloc open-door laminoplasty for cervical myelopathy: a magnetic resonance imaging study

We investigated lordotic alignment and posterior migration of the spinal cord following en bloc open-door laminoplasty for cervical myelopathy. Fifty-five patients (32 men and 23 women) were studied, with an average follow-up of 2.4 years. Radiological examination included evaluation of lordosis of the cervical spine and spinal cord, degree of enlargement of bony spinal canal, and the magnitude of posterior cord migration. We also correlated these changes with neurological improvement. Postoperatively, there was an average of 5% loss of cervical spine lordosis (P > 0.01) on radiographs and 12% reduction in the lordotic alignment of the spinal cord (P > 0.05) on magnetic resonance imaging. Postoperatively, the size of the bony spinal canal increased by 48%. Posterior cord migration showed a significant correlation with the preoperative cervical spine and spinal cord lordosis (P < 0.05). Thirty-seven (67%) patients with neurological improvement exceeding 50% showed significant posterior cord migration following laminoplasty compared with those demonstrating less than 50% improvement (P = 0.01). Our results suggest that a significant neurological improvement is associated with posterior cord migration after cervical laminoplasty.

High cervical myelopathy presenting with the numb clumsy hand syndrome

We report two patients with numb clumsy hands due to cervical spondylotic spinal cord compression. It is proposed that arterial insufficiency in the watershed area between the central and radial arterial systems of the cervical cord explains the sensory findings in the upper extremities with preservation of motor function. Although this is a rare conditions, its recognition is important since the prognosis is improved by early surgical decompression.

Histological and functional evaluation of experimental spinal cord injury: evidence of a stepwise response to graded compression

Most experimental spinal cord injury studies described to date have relied on a limited number of injury gradations, and have tacitly assumed that outcome (functional, histological, and/or neurophysiological) is a monotonically graded function of injury severity. In contrast, the present study provides evidence that functional and morphological outcome after spinal cord compression injury may occur in a discontinuous, non-graded manner in response to linearly graded injury levels. The thoracic spinal cord of adult rats was transiently compressed to thicknesses from 1.8 to 0.8 mm in 0.2 mm steps, or sham injury was administered. Open field motor behavior and segmental reflexes were evaluated up to 21 days post injury and correlated with histological measures and injury level. The highest correlation was between histological outcome and open field motor scores. Among the six injury groups, only three significantly different outcomes were apparent in the open field, reflex, and histological measures, consisting of the injury group pairs 1.8/1.6, 1.4/1.2, and 1.0/0.8 mm. At day 21, the 1.8/1.6 mm injury groups were also indistinguishable from the sham injury group. The implications of these findings in terms of therapeutic studies are discussed. Comparison of the temporal outcome patterns among contusion and compression injuries in rats and other species also revealed a significant species difference: a period of delayed or secondary functional loss reported in the guinea pig was not present in the rat.

Nonfunctioning malignant paraganglioma of the posterior mediastinum with spinal cord compression. A case report

STUDY DESIGN

Case report and review of the literature.

OBJECTIVE

To present a case with an uncommon nonfunctioning malignant paraganglioma of the posterior mediastinum with compression of the spinal cord. An update survey is given with respect to diagnostic, histopathologic, and therapeutic aspects of paragangliomas.

SUMMARY OF BACKGROUND DATA

Paragangliomas in the posterior mediastinum are uncommon and rarely may produce spinal cord compression. To illustrate the low incidence, only two cases of paraganglioma of the posterior mediastinum were reported by the Mayo Clinic, Rochester, Minnesota, during a 40-year period.

METHOD

Case report and review of the literature.

RESULT

The diagnosis was made by modern imaging techniques (computed tomography, magnetic resonance imaging, and metaiodobenzylguanidine scan) and verified by computed tomography guided per thoracic puncture. A wide local resection was performed; the patient is disease-free 1 year after surgery.

CONCLUSION

The uncertainty of prognosis and possibility of local recurrence of paragangliomas even after a long period emphasizes the importance of wide local surgical resection with or without adjuvant therapy and makes long-term follow-up and continued surveillance of the patient mandatory.

Posterior limbus vertebral lesions causing lumbosacral radiculopathy and the cauda equina syndrome

This report reviews our experience with spinal decompression for posterior limbus vertebral lesions or osteocartilaginous vertebral corner defects in the lumbar spine in 29 children and young adults. There were 19 male and 10 female patients with a mean age of 16.5 years (range, 9 to 24 years). Twenty-four patients were involved with various athletic activities. Clinical presentation included low back pain with a variable degree of radiculopathy in 25 patients and a cauda equina syndrome in four. The level of the affected spinal area was L1-2 in one patient, L2-3 in one, L3-4 in seven, L4-5 in 17, and L5-S1 in three. The preoperative imaging workup showed lateralised "non-calcified' or 'calcified' limbus vertebral defects in 13 patients and centrally displaced lesions in 16 patients. All patients underwent posterior spinal decompression with a slightly extended laminotomy, except for three patients who had a subsequent posterolateral fusion. All of the patients consequently returned to practice their favourite preoperative sport and lifestyle, but five discontinued their previous sports. We suggest that patients with posterior limbus vertebral lesions require careful diagnosis and therapy that are different from those with an ordinary lumbar disc herniation.