S YRINGOMYELIA and syringobulbia are

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1 Syringomyelia: A Look at Surgical Therapy J. GRAFTON LOVE, M.D. AND RICHARD A. OLAFSON, M.D. Mayo Clinic and Mayo Foundation, Section of Neurologic Surgery, and Mayo Graduate School of Medicine, University of Minnesota, Rochester, Minnesota S YRINGOMYELIA and syringobulbia are characterized by an accumulation of fluid in a cyst within the substance of the spinal cord or medulla or both. These cysts arise from various pathological processes and have been treated by surgical incision and drainage and by irradiation3,s Different materials have been inserted between the syrinx and the subarachnoid space to provide permanent drainage. In 1953, while attending a meeting of the Society of Neurological Surgeons in New Orleans, one of us heard Dr. Dean Echols explain his technique of using a tantalum wire to maintain a fistula between a syrinx of the spinal cord and the spinal subaraehnoid space and saw his patients who had had this operative procedure. The results were impressive, and we have employed this technique at our clinic since that time. In an effort to determine whether results have improved since the introduction of this technique, we have reviewed the records of patients with syringomyelia or syringobulbia and syringomyelia but without associated neoplasm who were operated on at the Mayo Clinic between 1948 and 196~. Evaluation Forty patients underwent 44 operative procedures for syringomyelia or syringomyelia and syringobulbia. These patients do not represent all those with syringomyelia who were seen at the Mayo Clinic, as only surgically verified cases were studied. We have analyzed the subjective complaints and objective neurological findings both before and after operation and throughout the follow-up period. In addition we have reviewed diagnostic studies, operative findings, and surgical methods employed. All patients considered as having adequate follow-up studies had neurological re-examinations at least 1 year after operation; the longest follow-up was 10 years. The majority of our patients Received for publication June ~8, Revision received Octoher ~5, had complete follow-up for ~ years or more. Thirty-five patients with syringomyelia did not have associated anomalies and were without evidence of other pathologic processes related to the central nervous system. Three of these, however, had minimal platybasia, but this did not contribute to the patients' symptoms. The remaining 5 patients had syringomyelia or syringobulbia and syringomyelia associated with Arnold- Chiari malformations. These 5 eases will be discussed separately. Symptoms The common complaint in syringomyelia is one of an asymmetrical diminution of sensation plus muscular weakness at and below the level of the cyst. Because of the preference of the syringomyelic process for the cervical and cervicothoracic region, diminution of sensation in the hands and forearms is a common early finding. Nineteen of our 40 patients said that radicular pain, corresponding to the level of the syrinx, had been an early symptom. The pain, as described, was indistinguishable from radicular pain produced by other space-occupying intraspinal masses. The symptom-complex most typical of syringomyelia includes bilateral diminution of temperature perception and asymmetrical hypalgesia. Proprioception and vibratory sensation are generally reduced to a moderate degree, whereas diminution of touch and pressure may be minimal. Characteristically, the motor disturbances in syringomyelia are those of weakness at or below the upper level of disturbed sensation. The weakness at the upper level of sensory disturbance is generally associated with atrophy and hyporeflexia indicative of denervation, whereas in the lower extremities there are hyperreflexia, pathologic reflexes, and spasticity indicative of corticospinal-tract involvement. The major motor disturbances distally are generally opposite the side of major sensory disturbance. 714

2 Surgical Treatment of Syringomyelia 715 Sex and Age In syringomyelia without complications, males tend to be affected more frequently than females (23 males to 12 females). Of the 5 patients with associated Arnold-Chiari malformation, 3 were males and 2 were females. Twenty-one of the 40 patients were between 20 and 40 years of age. The ages of patients at the time of surgery ranged from 12 to 60 years. A few patients did not have onset of symptoms prior to the age of 40 years. One of the 5 patients with syringomyelia-syringobulbia and associated Arnold- Chiari malformation had a Klippel-Feil anomaly with fusion of the C-1 and C-2 vertebrae as well. Of the other 35 patients, 30 patients had cervical syrinxes, 4 patients had thoracic syrinxes, and 1 patient had a cervical and thoracic syrinx. Diagnosis In all 35 patients with uncomplicated syringomyelia, the history and neurological examination suggested the diagnosis. In this group, 27 lumbar punctures were pe~5~ormed. Jugular compression done at the time of the lumbar puncture revealed no evidence of subarachnoid-space block in 19 cases. There was evidence suggestive of partial block in 5 and of complete block in 3 cases. Seventeen contrast-medium (Pantopaque) myelograms and 1 air myelogram were done in this group of patients. Of these 1~ demonstrated widening of the spinal cord at the level of the syrinx, and 2 showed no abnormal changes. Three of the contrast-medium myelograins and the 1 air myelogram revealed complete block at the level of the spinal-cord cyst. In the majority of patients with syringomyelia or syringobulbia and syringomyelia, the level of the lesion can be determined by neurological methods, and thus contrast myelography is not necessary. The value for cerebrospinal-fluid protein was elevated above the normal of 45 mg./100 nil. in 18 of the 27 patients in whom it was studied. Four patients had values of 750 rag. or greater; 2 of these had thoracic cysts and 2 had cervical syrinxes. Values for protein content in fluid removed from syringomyelic cavities ranged from 10 to 180 nlg. /100 ml. in 10 recorded specimens. The 1 specimen of 180 mg. was taken from a patient who had a cerebrospinal-fluid protein value of 900 mg. In the remaining 9 patients, the protein values of the fluid from the cysts was at least 20 rag. below the values of the cerebrospinal-fluid protein. The range of values of syrinx-fluid protein in these 9 patients was 10 to 40 rag./100 ml. Surgical Methods The surgical procedures were perfolnned by several neurological surgeons, providing various approaches for comparison. The procedures included the following: laminectomy alone, laminectomy with simple evacuation of the syrinx, laminectomy with syringostomy for drainage by the use of various materials to maintain cyst and subarachnoid communication (rubber drain, polyethylene tubing, cotton wicks, silk sutures, and tantalum-wire sutures), and suboccipital craniectomies with cervical laminectomies alone and with both simple drainage of cysts and syringostomies with permanent-drain materials. In all but 15 of the 44 operative procedures, some form of permanent drainage of the syrinx was attempted. Two of these operations were reoperations in which the spinal cyst was found to be collapsed. The initial procedure in 1 patient had been simple drainage of a thoracic cyst; and the second patient had had a tantalum-wire syringostomy for a cervical syrinx previously. Results of Surgical Treatment Results of surgical therapy were classified as excellent, good, or poor. Results were considered excellent when detailed examination revealed definite objective improvement in neurological status and when subjective improvement was noted by the patients themselves. Results were considered good when the neurological deficit did not increase or decrease and no subjective increase in deficit was noted by the patients themselves. However, most patients of this second group believed that they had definitely been improved by operation. Results were classified as poor if the neurological deficit increased after surgery even though the patients themselves may have considered their condition improved. Of the 35 patients with syringomyelia alone, 5 were lost to follow-up. The neurological status of these 5 patients 7 to 10 days after operation was essentially unchanged

3 716 J. Grafton Love and Richard A. Olafson from their preoperative condition. All 5 had cervical laminectolnies : 1 had simple drainage of the syrinx, 1 had polyethylene-tube syringostomy, 1 had silk-suture syringostomy, and ~ had tantalum-wire syringostomies in addition to cervical laminectomy. Excellent Results. Ten patients were classed as having obtained excellent results from surgical treatment of syringomyelia. In this group the follow-up periods ranged from 1 to 10 years. The 10 patients had symptoms referable to syringomyelia for from 1 to 8 years: In this group, ~ patients had cervical laminectomy with simple drainage of the cyst, ~ patients had cervical laminectomy with cotton-wick syringostomy, 1 patient had cervical laminectomy with silk-suture syringostomy, 4 patients had cervical laminectomy with tantalum-wire syringostomy, and 1 patient had suboccipital craniectomy plus cervical laminectomy with tantalumwire syringostomy. All 10 patients in this group were rehabilitated, and 5 returned to full-time work, 1 as a physician. Two patients who had been invalids were able to walk again and to care for themselves. Good Results (condition unchanged). The condition of 1~ patients was considered to have remained unchanged. All of these patients, however, believed that their condition had improved, and no worsening of neurological deficits was evident during the 1 to 4 year follow-up. Patients classified in this group had noted symptoms from 1 to ~5 years prior to operation. Surgical procedures in this group were of the varieties previously listed. Five patients underwent tantalumwire syringostomy. One patient had simple drainage of both a cervical syrinx and a thoracic syrinx. One patient had only a cervical laminectomy and the Cyst was undisturbed. Two patients had simple drainage of a syrinx, and ~ had silk-suture syringostomy. In 1 patient, polyethylene-tube syringostomy was performed in addition to laminectomy. In 3 instances, suboccipital craniectomy was carried out along with cervical laminectomy. Poor Results. Eight patients continued to deteriorate after the operation. Two of these patients had noted symptoms for 1 to years. The remaining 6 patients had had symptoms from 5 to ~6 years. Again there was no deviation from the basic surge)\v previously described in this series. Two patients in this group had a second surgical procedure at the same level: one had had simple drainage of a cyst 10 years previously and reoperation revealed that the syrinx was collapsed; the other had had laminectomy and tantalum-wire syringostomy 3 years before and re-exploration revealed a collapsed syrinx. One other patient in this group had had tantalum-wire syringostomy. Three of these patients had markedly elevated spinal-fluid protein values (~00 mg., 750 rag. and 900 mg./100 ml., respectively). One patient had a complete block to the flow of contrast medium at the T-9 level; the s had an alnmst complete block at the C-7 level, and the 3rd had generalized swelling of the entire cord from the upper cervical region through the conus medullaris. At operation the patient with the cervical lesion had simple drainage of the cyst; the patient with the thoracic lesion had a tantalum-wire syringostomy, and the patient with generalized swelling of the cord had low-thoracic laminectomy with a cotton-wick and polyethylene-tube syringostomy. No tumor was identified at operation in any of these 3 patients although their spinal fluid and lnyelographic findings were strongly suggestive of a neoplasm. The failure of operation in these patients may, therefore, be the result of a neoplasm that was not identified during the operation. Since we cannot prove this suspicion, these patients have been included in the group with poor surgical results. The remaining 3 patients whose signs and symptoms became worse during the follow-up period of 1 to 6 years underwent the following surgical procedures: ~, cotton-wick syringostomy, and 1, rubber-drain syringostomy in addition to laminectomy. Syringomyelia with Arnold-Chiari Syndrome. Of the 5 patients with syringomyelia and Arnold-Chiari malformation, ~ were lost to follow-up: one had a suboccipital craniectomy and cervical lamineetomy with simple drainage of the cyst, and the second had had fusion of the C-1 and C-~ vertebrae for a Klippel-Feil syndrome. The latter was treated with a suboccipital craniectomy, upper cervical laminectomy and simple drainage of the syrinx. At the time of discharge, the patient's neurological status was unchanged. The 3 remaining patients who were ade-

4 quately followed (~ to 6 years) each had a laminectomy (~, cervical and 1, thoracic). Two had tantalum-wire syringostomy, and the 3rd had simple drainage of the syrinx with subsequent tantalum-wire syringostomy 4 years later. All 8 continued to deteriorate. Two patients returned to our clinic where, 4 years after the initial procedure, they had suboccipital and upper-cervical laminectomy for decompression of the Arnold-Chiari malformation. One of these patients had a tantalum-wire syringostomy performed as a second surgical procedure. There was no further increase in neurological deficit, and this patient was able to resume his normal activities. The ~nd patient who had only a decompression as a 2nd procedure continued to deteriorate and eventually became incapacitated. The 3rd patient with Arnold- Chiari malfo~nation was treated by suboccipital craniectomy elsewhere and was lost to further follow-up. In summary, we have adequate follow-up data on 33 of 40 patients. If we include those patients who have had no further progression of disease as having satisfactory results, then surgical treatment in this condition has been beneficial in ~ of the 33 patients. Ten of the s patients with satisfactory results had tantalum-wire syringostomies. Discussion The cause of syringomyelia and syringobulbia has not been definitely established. I-~ The history and neurological examination usually suggest the diagnosis. These patients have the symptoms and signs of deep intramedullary lesions of the spinal cm'd or brain stem. The condition may be indistinguishable from other intramedullary mass lesions. Occasionally, an intraspinal extramedullary space-occupying lesion produces symptoms and signs that are suggestive of a syrinx. Contrast-medium myelography is the most satisfactory method of investigation of syringomyeliawhen neurological examination alone does not allow precise localization, because, in addition to giving the most reliable evaluation of the pathologic process by radiologic evidence, 4 it allows for analyses of cerebrospinal-fluid dynamics, cell abnormality and chemical concentrations. Fractional pneumoencephalography is helpful Surgical Treatment of Syringomyelia 717 and may be the radiologic study of choice for some bulbar lesions and those associated with the Arnold-Chiari malformation. The value of lumbar puncture and the study of cerebrospinal-fluid dynamics and the analysis of the fluid in all cases cannot be overemphasized. The Queckenstedt test should not be performed in the presence of suspected syringobulbia or Arnold-Chiari malformation. A neoplasm of the spinal cord should be considered in any patient with a complete block, and extra efforts should be taken at the time of operation to locate a tumor of the cord. Those patients exhibiting marked symptoms or neurological signs or both are served better when the spinal-fluid examinations are carried out on the day of the operation. A transverse-cord lesion may be precipitated in a patient with a spinal block if fluid is removed from below the block; the same complication may develop in a patient without a block when the Queckenstedt test is done. Myelography helps the neurosurgeon to plan his approach to the pathologic process in the cord. Our experience suggests that the duration of symptoms has a definite bearing on the response to surgery. Patients with long-term symptoms and evidence of severe neurological deficit respond less well to therapy 4 than those patients with histories of symptomatology of only 1 to ~ years. Patients with rapidly progressing deficits also respond less well to surgery. These impressions lead us to urge complete diagnostic study of patients with suspected syringomyelia as soon as a neurological deficit is detected. Early diagnosis and therapy assure the best possible results. We believe that surgical decompression accompanied by syringostomy is the treatment of choice, and that tantalum-wire syringostomy is the most effective means of providing prolonged or permanent drainage of the syrinx. The shorter the pre-operative history and the less severe the neurological deficit, the more likely that surgical intervention will be successful. Surgical intervention is not curative or even palliative in all cases of syrinx in the spinal cord or brain. Variations in surgical results are likely, due to underlying differences in the basic pathology. 1,4 The symptoms of syringomyelia result from destruction of spinal cord substance;

5 718 J. Grafton Love and Richard A. Olafson cells and fibers in the central nervous system that have been destroyed do not regenerate. Hence, objective neurological improvement can occur only in those patients in whom the pressure within the cyst has been released. This may bring about improvement in uninterrupted fibers whose function has been reduced by pressure. These facts are sufficient justification for the surgical treatment of syringomyelia, for if nothing is done to stop the progressive enlargement of the syrinx the patient ultimately becomes markedly disabled if the lesion is in the cord or dies if the lesion is in the medulla. References 1. GARDNER, W. J., and ANGEL, J. The mechanism of syringomyelia and its surgical correction. Clin. Neurosurg., 1959, 6: ~. KIRGIS, H. D., and ECItOLS, D.H. Syringo-encephalomyelia. Discussion of related syndromes and pathologic processes, with report of a case. J. Neurosurg., 1949, 6: ,~. NETSKY, M.G. Syringomyelia: a clinicopathologic study. Arch. Neurol. Psychiat., Chicago, 1953, 70: PITTS, F. W., and GROFF, R. A. Syringomyelia: current status of surgical therapy. Surgery, 1964, 56: POSER, C.M. The relationship between syringomyelia and neoplasm. Springfield, Ill.: Charles C Thomas, 1956, 98 pp.