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J Neurosurg: Spine / Volume 17 / September 2012

J Neurosurg Spine 17:199–211, 2012

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In the past it was believed that posttraumatic syringo-myelia was the result of a severe spinal cord injury and that it developed from an area of myelomalacia

after resorption of intramedullary blood and breakdown products of destroyed cord tissue.7 Although treatment was based on syrinx shunting to various compartments for decades, modern treatment principles follow differ-ent concepts, which have mainly evolved since the intro-duction of MRI in the 1980s. Current concepts recognize and treat the pathophysiology of syringomyelia, which is related to obstruction of CSF flow.24,32 In patients with posttraumatic syringomyelia, posttraumatic arachnopa-

thies at the injury level disturb CSF flow and require sur-gical management to reduce the syrinx and to stabilize the neurological status. This relationship between spinal arachnoid scarring and syringomyelia was recognized as early as 1938 by Adelstein,2 but its importance was not appreciated for a long time. The modern treatment of posttraumatic syringomyelia started in the 1980s with Bernard Williams,75 who still inserted syringoperitoneal or syringopleural shunts but also attempted to create a free CSF passage at the level of posttraumatic arachnoid scarring.

Since 1991, all patients presenting with spinal cord

Treatment of posttraumatic syringomyelia

Clinical article

Jörg KleKamp, m.D.Department of Neurosurgery, Christliches Krankenhaus, Quakenbrück, Germany

Object. This paper presents results of a prospective study for patients undergoing surgery for posttraumatic syringomyelia between 1991 and 2010.

Methods. A group of 137 patients with posttraumatic syringomyelia were evaluated (mean age 45 ± 13 years, mean follow-up 51 ± 51 months) with pre- and postoperative MRI and clinical examinations presenting in this period and followed prospectively by outpatient visits and questionnaires. Surgery was recommended for symptomatic pa-tients with a progressive course. Short-term results were determined within 3 months of surgery, whereas long-term outcomes in terms of clinical recurrences were studied with Kaplan-Meier statistics.

Results. Three groups were distinguished according to the type of trauma: Group A, patients with spinal trauma but without cord injury (ASIA E, n = 37); Group B, patients with an incomplete cord injury (ASIA C or D, n = 55); and Group C, patients with complete loss of motor function or a complete cord injury (ASIA A or B, n = 45). Overall, 61 patients with progressive symptoms underwent 71 operations. Of these operations, 61 consisted of arachnolysis, untethering, and duraplasty at the trauma level (that is, decompression), while 4 ASIA A patients underwent a cordec-tomy. The remaining procedures consisted of placement of a thecoperitoneal shunt, 2 opiate pump placements, and 2 anterior and 1 posterior cervical decompression and fusion. Seventy-six patients were not treated surgically due to lack of neurological progression or refusal of an operation. Neurological symptoms remained stable for 10 years in 84% of the patients for whom surgery was not recommended due to lack of neurological progression. In contrast, 60% of those who declined recommended surgery had neurological progression within 5 years. For patients present-ing with neurological progression, outcome was better with decompression. Postoperatively, 61% demonstrated a reduction of syrinx size. Although neurological symptoms generally remained unchanged after surgery, 47% of af-fected patients reported a postoperative improvement of their pain syndrome. After 3 months, 51% considered their postoperative status improved and 41% considered it unchanged. In the long-term, favorable results were obtained for Groups A and C with rates for neurological deterioration of 6% and 14% after 5 years, respectively. In Group B, this rate was considerably higher at 39%, because arachnolysis and untethering to preserve residual cord function could not be fully achieved in all patients. Cordectomy led to neurological improvement and syrinx collapse in all 4 patients.

Conclusions. The technique of decompression with arachnolysis, untethering, and duraplasty at the level of the underlying trauma provides good long-term results for patients with progressive neurological symptoms following ASIA A, B and E injuries. Treatment of patients with posttraumatic syringomyelia after spinal cord injuries with preserved motor functions (ASIA C and D) remains a major challenge. Future studies will have to establish whether thecoperitoneal shunts would be a superior alternative for this subgroup.(http://thejns.org/doi/abs/10.3171/2012.5.SPINE11904)

Key WorDs • posttraumatic tethering • spinal arachnoiditis • syringomyelia

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200 J Neurosurg: Spine / Volume 17 / September 2012

pathologies have been entered into a spinal cord data-base and followed prospectively. In 1997, a first study on patients with syringomyelia related to spinal arachnoid scarring using this database was published comparing results for traditional syrinx shunting operations with a modified Williams technique that established a free CSF passage at the level of arachnoid scarring in combination with an expansile duraplasty without additional shunting of the syrinx.33 This technique had been developed inde-pendently at the University of California in Los Ange-les by Ulrich Batzdorf in the late 1980s and at Nordstadt Hospital Hannover, Germany, in the early 1990s based on the original ideas of Bernard Williams. The 1997 study came to the conclusion that improving CSF flow at the in-jury level and enlarging the subarachnoid space gave far better long-term results than shunting operations.33 Since then, a number of other groups have published their favor-able results with this technique as well.3,15,29,43,50,53,67

The present paper describes the treatment results for patients with posttraumatic syringomyelia who were treated by improving CSF passage at the trauma level and presented between 1991 and 2010.

MethodsPatient Population

A total of 1151 patients with syringomyelia presented at the Nordstadt Hospital in Hannover, Germany, between 1991 and 2003 (chairman until 2002, Madjid Samii, M.D.; chairman in 2003, Michael Gaab, M.D.) or the Christ-liche Krankenhaus in Quakenbrück, Germany, between 2004 and 2010 with spinal cord pathologies and had their data entered into the spinal cord database. Apart from general patient data and specific features of each spinal cord pathology, the neurological examinations before sur-gery, before discharge from the hospital, 3 months post-operatively, and yearly thereafter were documented with respect to individual symptoms using a scoring system (Table 1).34 In 137 of the 1151 cases, the syringomyelia was related to trauma, and these cases were included in the present study. All patients presented with MR images. Additional cardiac-gated cine MRI studies were per-formed in some patients if the CSF flow obstruction was expected to extend beyond the injury level—as in patients who had undergone intradural operations—or in those

without obvious spinal injuries. Depending on the associ-ated posttraumatic pathology of the spine, CT scans and conventional radiographs were obtained. Myelograms and postmyelographic CT scans were obtained only in excep-tional cases, such as in patients with severe metal artifacts on MRI. In general, surgery was recommended as soon as neurological symptoms started to progress. For patients wishing to undergo surgery predominantly for pain relief, it was emphasized before surgery that successful opera-tions with resolution of the syrinx do not ensure improve-ment of dysesthetic or neuropathic pain syndromes even if other neurological symptoms may improve. In patients with profound degenerative changes of the cervical spine the decision which pathology required treatment first—the arachnopathy or the degenerative process—was based on clinical examinations.

Surgical Management

Decompression. All operations were performed with the patient in the prone position. In patients who had un-dergone fusion and for those with spinal stenosis, lami-nectomies were performed to expose the dura mater. In all other patients, the lamina were removed with a small craniotome so that they could be reinserted with titanium miniplates at the end of the procedure. After exposure of the dura, the extent of the arachnoid pathology was visu-alized with ultrasound. Then the dura was opened under the operating microscope in the midline without opening the arachnoid mater. With the dura held open with sutures, the arachnoid pathology could be studied and adequate cranial and caudal exposure was ensured to gain access to normal and unaffected subarachnoid space on either side. Only sharp dissection of the arachnoid was used to avoid tearing blood vessels which might be embedded in the arachnoid, as illustrated elsewhere.35,36 The arachnoid was grasped with microforceps and held under slight ten-sion during dissection. The posterior medial septum was identified first and incised with microscissors, leaving the so-called intermediate layer of the arachnoid, which covers spinal cord blood vessels,46 untouched on the cord surface. Once the area of the arachnopathy was reached, sharp dissection was continued in the same fashion. In this way, a free CSF passage in the posterior subarach-noid space could be created in every patient across the

TABLE 1: Neurological scoring system

Score PainSensory Disturbance,

Dysesthesias Motor Weakness Gait AtaxiaSphincterFunction

5 none normal full power normal normal4 slight, no medication present, not significant movement against

resistanceunsteady, no aid slight disturbance, no

catheter3 good control w/ med-

icationsignificant, function not restricted

movement against gravity

mobile w/ aid residual, no catheter

2 insufficient control w/ medication

some restriction of function movement w/o gravity few steps w/ aid rarely incontinent

1 severe despite medication

severe restriction of function contraction w/o movement

standing w/ aid frequent use of catheter

0 incapacitating incapacitated function plegia plegia permanent catheter


Posttraumatic syringomyelia

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region of trauma. Dissection was then continued laterally on either side toward the dentate ligaments. This led to complete untethering of the cord in the majority of cases. No arachnoid dissection was performed anterior to the dentate ligaments unless the patient had suffered a com-plete spinal cord injury. In those cases, a complete un-tethering—posteriorly, laterally, and anteriorly—was per-formed. In all other patients, areas of anterior arachnoid scarring were left untouched. If syrinx shunts had been implanted close to or at the level of the posttraumatic arachnopathy they were removed, provided they were not stuck inside the spinal cord. Syrinx shunts implanted in areas unaffected by the posttraumatic arachnopathy were left in place. At closing of the microsurgical part of the operation, an expansile duraplasty was performed with a tight running suture and finally lifted up with tenting sutures on either side. To avoid scar formation and tether-ing between duraplasty and spinal cord, artificial material was preferred for duraplasty (Gore-Tex, W. L. Gore & As-sociates GmbH) (Figs. 1 and 2). In patients with profound soft tissue scarring after multiple surgeries or severe soft tissue trauma, a lumbar drain was placed and removed after 5–10 days to prevent the formation of a CSF fistula.

Cordectomy. For patients with a complete cord in-jury, a cordectomy was offered as an alternative when-ever surgery aiming at improving the CSF pathway was considered not likely to succeed, as in patients who had undergone multiple shunting operations (Fig. 3) or those with severe posttraumatic kyphosis. For that purpose, the same surgical approach was used as described for decompression. After the dura was opened at the injury level, the spinal cord was detached from all fixations to surrounding structures and then completely transected immediately above the area of cord destruction. Another transection was then performed below the level of cord

injury to remove the destroyed cord segment. With the cranial and caudal part of the remaining cord untethered in this fashion, a duraplasty was inserted and the wound closed as described.

Outcome Analysis and Statistical MethodsAfter discharge from the hospital, all surgically treat-

ed patients were examined 3 months postoperatively, and yearly follow-up was conducted by means of further out-patient visits or questionnaires.

For statistical tests of significance, Student t-tests and Fisher tests were employed. Surgical morbidity was defined as a new, permanent postoperative deficit or a permanent aggravation of a preexisting deficit within 30 days after the operation. Long-term follow-up data were analyzed with Kaplan-Meier statistics30 to determine the percentages of patients with a stable neurological sta-tus (progression-free survival) or progressive symptoms (clinical recurrence).

Mean values are presented with standard deviations.

ResultsPreoperative Data

Between 1991 and 2010, 137 patients with post-traumatic syringomyelia (101 males, 36 females) were encountered. The mean age at presentation was 47 ± 14 years (range 3–74 years) (Table 2). The mean duration of follow-up was 55 ± 55 months (range 2 weeks–19 years). According to the degree of spinal cord involvement with the underlying trauma, 3 groups could be distinguished.

Group A was made up of patients with spinal injury without spinal cord trauma. Neurological symptoms had either been entirely absent or had consisted of radicular

Fig. 1. A: Sagittal T2-weighted MR image obtained in a 49-year-old male patient 30 years after a conservatively managed fracture at T-6 that was not associated with any neurological symptoms. It shows a syrinx from the T-1 to the T-10 level and a profound kyphosis. Ten years after the accident the patient started to notice weakness in his left leg. A syrinx was found between T-4 and T-10, which subsequently ascended to T-1. B: Axial T2-weighted image demonstrating an area of posterior tethering on the right side. At presentation 20 years after the onset of new symptoms, the patient had to use a walker due to a spastic paraparesis. A correction of the kyphosis was discussed but refused by the patient. He underwent T-6 and T-7 laminotomy with arachnolysis and duraplasty. C: Postoperative MR image obtained 7 months after surgery showing a reduction of the syrinx. As of this writing, the patient’s neurological situation has remained stable for 3 years.

J. Klekamp


symptoms that resolved completely (ASIA E4). There were 37 patients in this group (Fig. 1).

Group B was made up of patients who had an in-complete spinal cord injury with preserved motor func-tion with or without subsequent recovery (ASIA C or D). There were 55 patients in this group (Fig. 2).

Group C was made up of patients who had a complete spinal cord injury or incomplete cord injury with complete loss of motor function without subsequent recovery (ASIA A or B). There were 45 patients in this group (Fig. 3).

All syrinx cavities started at the level of trauma and expanded from there (Fig. 2). In 46% of cases, they ex-tended in the rostral direction, in 20% in the caudal di-rection, and in the remaining 36%, they extended in both directions, with the rostral component predominating in all cases. The lower the spinal level of trauma, the more likely the syrinx was to expand only in rostral direction and vice versa. There was no correlation between syrinx orientation and severity of the original cord injury.

The interval between trauma and the onset of new neu-rological symptoms was extremely variable and extended between 1 month and 46 years (mean 130 ± 121 months). From the time of symptom onset, an average of 56 ± 71 months (range 1 week–30 years) passed before the patients presented for neurosurgical evaluation. Clinical histories related to syringomyelia tended to be shorter for patients with more severe cord injuries (p = 0.1005, Fisher test), but there was no similar trend for a shorter interval between trauma and the onset of syrinx-related symptoms for pa-tients with more severe cord injuries (Table 2).

The most common initial symptoms of posttraumatic syringomyelia were a new motor deficit (the initial symp-tom in 28% of patients) and a new type of pain (in 26%). New sensory deficits, dysesthesias, or a worsening of gait were less common initial signs (in 14% each). Two pa-tients noticed sphincter disturbances and one had swal-lowing problems as the first new sign. Table 3 lists the percentages for individual neurological symptoms in all

Fig. 2. A: Sagittal T2-weighted MR image obtained in a 46-year-old male patient 17 months after a motor vehicle accident that caused a spinal cord concussion with a persistent sensory level at T7–8, showing a small syrinx from T-2 to T-4. B: Sagittal MR image obtained 1 year later showing a slight expansion of the syrinx now crossing the level of the T1–2 disc space. C and D: Axial T2-weighted images, adjacent slices. The first image (C) poorly demonstrates the surface contour of the cord at the lower end of the syrinx due to pulsation artifact from the arachnoid pouch that compresses the cord posteriorly on the next axial image below that level (D). E: Axial MR image showing that the demarcation and form of the spinal cord returned to normal below the arachnopathy at T-5. The abrupt change of syrinx caliber at T-4, the cranial ascent of the syrinx, the slight posterior compression at T-4, and the motion artifacts at that level are indirect signs of the posttraumatic arachnopathy causing the syrinx. A decompres-sion at T-4 was undertaken. F: Postoperative MR image obtained 3 months after decompression showing complete resolution of the syrinx. The patient’s clinical condition was unchanged.



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groups, providing an overview of the clinical spectrum at presentation.

ManagementOf 137 patients with posttraumatic syringomyelia, 76

patients (20 of 37 in Group A, 27 of 55 in Group B, and 29 of 45 in Group C) were not treated surgically, either for lack of progression of neurological symptoms (50 pa-tients) or because they refused surgery (26 patients). The 61 remaining patients underwent 71 surgical interven-tions (Table 4). Two of these made the decision to un-dergo surgery 6 and 11 years after the initial presentation.

First OperationsAmong the surgically treated patients, 5 of 17 pa-

tients in Group A, 9 of 28 patients in Group B, and 3 of 16 patients in Group C had already undergone placement of syrinx shunts without success. The remainder had under-gone no surgery other than interventions to deal with the initial spine trauma.

Four patients with asymptomatic syringomyelia (1 from Group A, 1 from Group B, and 2 from Group C) underwent cervical fusion procedures without decom-pression. The Group A patient and 1 Group C patient un-derwent posterior fusions for instability, and the Group B patient and 1 Group C patient underwent ventral fusions for cervical disc disease. One Group A patient refused de-compression surgery and was treated with an opiate pump for his pain syndrome. One patient in each of Groups B and C was treated with a cordectomy; the Group B patient had progressed from ASIA C to ASIA A, and the Group C patient presented after multiple shunting attempts and had posttraumatic kyphosis (Fig. 3).

Subsequent OperationsOne patient in Group C underwent subsequent inser-

tion of an opiate pump for treatment of persistent pain despite successful treatment of the syrinx with stabiliza-tion of his neurological status by decompression. Eleven patients experienced a clinical recurrence after decom-pression. Four of these refused further surgical attempts. The other 7 patients underwent 9 subsequent surgeries: 1 patient in Group C underwent a cordectomy for recur-

Fig. 3. Left: Sagittal T2-weighted MR image obtained in a 38-year-old male patient 20 years after a burst fracture at T6–7 that resulted in complete paraplegia. Within 3 years before presentation the patient un-derwent 7 attempts at syrinx shunting at other institutions (to control the syrinx) without any success. Due to the postsurgical arachnoid scarring and the kyphosis at the injury level, a decompression was considered unlikely to stabilize the ascending neurological symptoms. Right: Af-ter cordectomy, the syrinx completely collapsed and the patient noticed recovery of his hand function mainly due to improved sensory function. As of this writing the improvement has lasted for 2 years.

TABLE 2: Summary of clinical and demographic characteristics in 137 patients with posttraumatic syringomyelia*

Characteristic Group A Group B Group C All Pts

mean age at presentation (yrs) 46 ± 15 49 ± 13 45 ± 13 47 ± 14mean clinical history (mos)† 80 ± 97 50 ± 58 44 ± 54 56 ± 71mean latency (mos)‡ 103 ± 88 160 ± 132 119 ± 127 130 ± 121trauma level cervical 13 8 10 31 thoracic 20 36 34 90 conus 4 11 1 16

* Group A comprised patients with no spinal cord trauma (n = 37); Group B, patients with incomplete cord trauma (n = 55); Group C, patients with complete cord trauma (n = 45). For details, see Methods. Abbreviation: Pts = patients.† Duration from onset of symptoms of syringomyelia to presentation.‡ Interval between the initial trauma and the onset of new neurological symptoms.

TABLE 3: Symptoms at presentation

Percentage of Pts w/ Symptom DescribedSymptom Group A Group B Group C All Pts

hypesthesia 84 96 73 85dysesthesia 46 62 42 51pain 70 71 73 71motor weakness 78 85 62 77gait ataxia 89 94 100 95sphincter disturbance 57 71 100 78

J. Klekamp


rence of symptoms and syringomyelia. All other subse-quent surgeries involved 6 patients in Group B: 4 patients underwent revision at the site of decompression for recur-rent tethering of the spinal cord. One patient in Group B had progressed to ASIA A after multiple syrinx shunt-ing operations at another institution before presentation. A cordectomy was suggested but refused. After unsuc-cessful decompression he underwent placement of a the-coperitoneal shunt with short-term success (1 year), and then, after it became blocked, finally accepted the cordec-tomy, which was followed by sustained neurological im-provement. One patient with a cervical trauma underwent a second posterior decompression plus fusion and an an-terior revision with corpectomy, vertebral reconstruction, and plating to deal with spinal stenosis and instability af-ter the initial decompression.

Outcome for Surgically Treated PatientsAmong 61 operations undertaken with the goal of

improving CSF flow at the site of the trauma, 10 compli-cations were encountered, for a complication rate of 16%. Three postoperative hematomas and 3 wound infections, of which 2 were aseptic, were observed. One CSF leak developed and 1 paraplegic patient experienced a cardiac arrest 3 hours after surgery but recovered with no se-quelae after resuscitation. Two patients suffered a urinary tract infection. Permanent surgical morbidity (permanent neurological worsening within 1 month after surgery) was observed after 4 operations (6.5%). Transient postopera-tive deterioration occurred in 8% of patients and mainly involved sensory function.

Table 5 gives an overview of postoperative changes in syrinx size after decompression and shows that the best results were obtained in Group C. The rate of postopera-tive syrinx decrease was not influenced by the presence or absence of kyphotic angulation at the injury level (syr-inx decrease in 71% of patients with kyphosis and 61% of those without) (Fig. 1). After cordectomy, all syrinx cavities collapsed completely (Fig. 3), while syrinx cavi-ties remained unchanged after ventral or posterior cervi-cal fusion.

Short-term clinical outcome data for patients who underwent decompression surgery are provided in Table 6. Overall, significant improvements were observed for dysesthesias and pain in this period, whereas other neu-

rological symptoms remained unchanged. These trends were observed for each individual patient group. Overall, 51% considered their postoperative outcome as improved and 41% as unchanged, whereas 8% reported further worsening within 3 months after surgery. Overall, 47% of affected patients reported an improvement of dysesthetic or neuropathic pain syndromes with the remainder ob-serving no change.

Seven surgically treated patients were lost to follow-up. Long-term outcomes in terms of neurological recur-rence rates are presented in Table 7. The analysis revealed profound differences between Groups A, B, and C (Fig. 4), whereas a posttraumatic kyphosis did not have a nega-tive predictive effect. The best results were observed for patients in Groups A and C, with the difference from the results in Group B just failing to reach statistical signifi-cance (p = 0.07, log-rank test). Comparing first and re-vision surgeries demonstrated a trend for a lower recur-rence rate in patients undergoing a first decompression. In the long term, however, recurrence rates after 10 years were almost identical, with no statistically significant dif-ferences. Likewise, recurrence rates tended to be lower for patients without posttraumatic kyphosis, but this dif-ference was not statistically significant (Table 7).

All patients treated with cordectomy demonstrated sustained neurological improvements without a clinical recurrence during follow-up.

Among 7 patients undergoing further operations af-ter a first decompression, 4 were eventually stabilized. The condition of 3 patients in Group B continued to dete-riorate, and the patients declined further operations.

Outcome for Patients not Treated SurgicallySeventy-six patients (20 in Group A, 27 in Group B,

and 29 in Group C) were not treated surgically. Of these

TABLE 4: Types of operations*

TypeGroup A Group B Group C Total

1st Op 2nd Op Total 1st Op 2nd Op Total 1st Op 2nd Op Total 1st Op 2nd Op Total

decompression 14 0 14 25 4 29 13 0 13 52 4 56decompression & fusion 1 0 1 1 1 2 2 0 2 4 1 5cordectomy 0 0 0 1 1 2 1 1 2 2 2 4posterior fusion 1 0 1 0 0 0 0 0 0 1 0 1ventral fusion 0 0 0 1 1 2 0 0 0 1 1 2thecoperitoneal shunt 0 0 0 0 1 1 0 0 0 0 1 1opiate pump 1 0 1 0 0 0 0 1 1 1 1 2

* Values represent numbers of operations.

TABLE 5: Postoperative changes in syrinx size after decompression

Percentage of CasesPostop Size Group A Group B Group C All Pts

decrease 50 55 88 61no change 36 24 6 24increase 14 21 6 15



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76 patients, 19 were lost to follow-up. Of the remain-ing 57 patients, 38 remained in stable condition for up to 17 years after the initial presentation (mean 67 ± 61 months). This figure corresponds to rates of progression-free survival of 79% after 5 years and 65% after 10 years in the Kaplan-Meier analysis. There were no differences in outcome based on the type of cord trauma or whether patients had previously undergone shunt placement. The condition of 34 of the 38 patients in whom conservative management was recommended remained stable, while that of 4 patients progressed. Of 19 patients with a surgi-cal recommendation who had refused the operation ini-tially, 4 subsequently underwent decompression surgery in 2011 and 2012; the condition of 11 patients remained unchanged for up to 6 years while that of 4 patients de-teriorated. Comparing progression-free survival rates for patients with or without a recommendation for surgery revealed a significantly worse outcome for patients with a surgical recommendation after 5 years (40% vs 94%

after 5 years and 0% vs 84% after 10 years, respectively; p = 0.0004, log-rank test). In 6 of 8 patients with neuro-logical deterioration, the progression was related to the posttraumatic cord tethering, with worsening of gait and sphincter functions, rather than the syrinx, with ascend-ing neurological deficits.

Discussion

Incidence and Pathophysiology

The incidence of posttraumatic syringomyelia is dif-ficult to determine. Estimates are based on trauma cen-ter surveys of patients who have had spinal cord injury and were followed up regularly with MRI. These patients carry a risk for neurological deterioration of 2% per year from various causes—spinal instability, cord tethering, cord compression, and syringomyelia.55 However, areas of cord destruction followed by cystic degeneration (my-elomalacia) and formation of a new cyst expanding from the level of cord injury (posttraumatic syringomyelia) are not differentiated in most studies. Cystic changes at the site of cord trauma are common and occur in at least 50% of patients after severe spinal cord injuries.5 In a survey of spinal cord–injured patients 28% were identified with a posttraumatic syrinx.49 The spinal level of trauma ap-pears to be irrelevant to the probability of developing a posttraumatic syrinx.76 It has been proposed that the like-lihood of developing posttraumatic syringomyelia cor-relates with the severity of cord injury.16,50,69 However, posttraumatic syringomyelia may develop in patients af-ter complete recovery from cord injury63,68 as well as in patients without any spinal cord injury at all.13

The treatment of posttraumatic syringomyelia as de-scribed in this paper is based on the pathophysiological link to posttraumatic arachnoid scarring and CSF flow obstruction at the level of trauma.76 Spinal cord tether-ing may contribute further to its development.9 Syringo-myelia does not require a spinal cord injury to develop. Arachnoid scarring has been shown to raise the subarach-noid space pressure above the obstruction in a computer

TABLE 6: Early postoperative clinical results after decompression*

Group Group A Group B Group C All Pts

hypesthesia preop 3.1 ± 0.5 2.7 ± 0.8 3.1 ± 1.0 2.9 ± 0.8 postop 3.1 ± 0.8 3.1 ± 0.8 3.2 ± 1.1 3.2 ± 0.8 3 mos 3.2 ± 0.7 3.1 ± 0.7 3.3 ± 1.2 3.3 ± 0.8dysesthesia preop 3.4 ± 1.3 3.9 ± 1.0 3.7 ± 1.2 3.8 ± 1.1 postop 3.9 ± 0.9 4.1 ± 0.9 4.0 ± 1.1 4.1 ± 0.9 3 mos 3.9 ± 0.9 4.1 ± 0.8 4.1 ± 1.1 4.2 ± 0.9†pain preop 3.8 ± 1.2 3.9 ± 1.0 3.3 ± 1.0 3.7 ± 1.1 postop 4.0 ± 1.0 4.2 ± 0.7 3.8 ± 1.0 4.0 ± 0.9 3 mos 4.2 ± 0.7 4.1 ± 0.9 3.9 ± 1.0 4.1 ± 0.9†motor weakness preop 3.5 ± 0.8 3.1 ± 1.0 3.7 ± 1.2 3.4 ± 1.0 postop 3.3 ± 0.8 3.2 ± 1.1 3.8 ± 1.2 3.4 ± 1.0 3 mos 3.4 ± 0.9 3.2 ± 1.0 3.9 ± 1.3 3.5 ± 1.0gait ataxia preop 2.7 ± 1.2 2.1 ± 1.4 2.4 ± 1.4 postop 2.5 ± 1.3 2.1 ± 1.4 — 2.4 ± 1.4 3 mos 2.6 ± 1.3 2.1 ± 1.4 2.4 ± 1.4bladder dys preop 3.4 ± 1.5 2.6 ± 1.8 2.9 ± 1.8 postop 3.2 ± 1.6 2.6 ± 1.9 — 2.9 ± 1.9 3 mos 3.2 ± 1.6 2.7 ± 1.9 2.9 ± 1.9overall result improved 38% 52% 66% 51% unchanged 50% 39% 35% 41% worse 13% 9% — 8%

* Dys = dysfunction.† Significant difference between preoperative and 3-month postopera-tive scores (p < 0.01).

TABLE 7: Clinical recurrence rates after decompression or conservative management

Recurrence Rate (%)Treatment & Group 5 Yrs 10 Yrs

decompression Group A 6% 6% Group B 38% 74% Group C 14% — all 28% 55% 1st surgery 22% 56% revision surgery 38% 53%conservative management all 21% 35% surgery not advised 6% 16% surgery refused 60% 100%

J. Klekamp


model11 and in experimental studies.38 Obstruction of CSF flow also causes changes in the distribution of extra-cellular fluid in the spinal cord,38 leading to syringomy-elia.24,32,37 Increased flow in the perivascular spaces has been implicated in this effect.10,14,32,38,60,61 There appears to be an evolution from spinal cord edema (that is, the so-called presyrinx state) to syringomyelia.21 Once syringo-myelia has developed, the increased intramedullary pres-sure45 and fluid movement inside the syrinx3,64 may lead to progressive spinal cord damage23,52,59 and neurological symptoms.

Apart from the syrinx, posttraumatic tethering and compression of the cord by arachnoid scars, pouches, and cysts at the level of injury may also cause progressive neurological deficits1,16,18–20,42 (Figs. 1 and 2). This aspect is of particular significance for patients of Group B in this study. A further aspect to consider is posttraumatic spinal deformity. Restoration of spinal alignment in the acute phase may decrease the risk of posttraumatic sy-ringomyelia1,6,49,58 and should improve the chance of suc-cessful treatment for those patients who have developed it. Patients with dislocated spine fractures and spinal ste-nosis tend to develop a posttraumatic syrinx earlier than those without spinal canal compromise.49,69 A study by Perrouin-Verbe et al.,49 published in 1998, determined a cutoff point of 30% canal stenosis as a predictor for the development of a posttraumatic syrinx.

Therefore, patients with a posttraumatic syrinx may present new neurological symptoms from a variety of causes: spinal cord tethering or compression and spinal instability, as well as syringomyelia. Furthermore, de-generative processes of the spine have to be considered. Every patient with a posttraumatic syrinx requires a thor-ough evaluation to address the right target for surgery.Neuroradiological Diagnosis

Neuroradiological assessment in patients with post-traumatic syringomyelia has to account for the different mechanisms that may be involved in neurological pro-gression. It is not sufficient to just demonstrate the ex-act extent of the syrinx. To demonstrate a posttraumatic arachnopathy, a technically adequate MRI examination

is required, with particular emphasis on thin-slice axial T2-weighted images at the area of injury (Figs. 1 and 2). As the arachnoid is not visible on conventional MR im-ages, indirect signs of the arachnopathy have to be looked for, such as an area of cord displacement, adhesion, or compression18,28 (Figs. 1 and 2). As arachnoid webs move with the pulsatile flow of CSF, they may cause motion artifacts, distorting the surface contour of the spinal cord right at the level of the arachnopathy in sagittal and axial T2-weighted images (Fig. 2).28 Constructive interference steady state sequences can be used not only for the dem-onstration of the syrinx26 but may sometimes be helpful to detect arachnoid webs, scars, and cysts, because this tech-nique is less susceptible to CSF flow artifacts.26 Cine MRI should be applied to demonstrate the extent and precise levels of CSF flow obstruction,3 particularly in patients in whom previous operations may have caused additional arachnoid scarring on top of the posttraumatic arachnop-athy or in those without cord injury. In all patients, the syrinx starts at the level of injury and expands mainly in the rostral direction in the majority of patients12,25 (Fig. 2).

Myelography, on the other hand, is less sensitive than cine MRI for demonstrating areas of CSF flow obstruc-tion,44 because arachnopathies may involve the posterior subarachnoid space only,16 and intrathecal contrast may bypass such areas almost without any delay via unob-structed sections of the subarachnoid space.

For patients with spinal instrumentation, MRI may no longer be able to show the intradural anatomy at the injury level in sufficient detail. In such instances CT my-elography is recommended and extremely helpful for in-traoperative orientation.

Depending on the posttraumatic anatomy of the spine, a CT in bone window technique and functional ra-diographs may be required to demonstrate the size and form of the spinal canal in the involved area and to rule out insufficient instrumentation or spinal instabilities.

Clinical PresentationThe clinical picture is characterized by an extremely

variable interval after trauma before symptoms of post-traumatic syringomyelia begin.3,11,15,17,24,28,39,42,50,53,54,57,66,67,76 When symptoms develop, they may involve pain, sensory changes, motor weakness, deteriorations of gait, auto-nomic dysfunctions, or increased spasticity.3,12,16,18,39,42,54,76 Depending on the presence and severity of cord injury, the clinical course and the major concerns of the patients vary considerably. Patients in Group A became symptom-atic although they had a functionally intact spinal cord after the initial trauma. This explains the longer history before the diagnosis is made and the less severe neuro-logical symptoms before surgery compared with patients in Groups B and C. For patients in Group B, the most common major complaint was a deterioration of gait, which could be attributed to cord tethering or syringomy-elia. The clinical course should be considered in surgical planning: A patient with progressive gait problems but no signs of ascending neurological deficits will require a successful untethering procedure in addition to restora-tion of CSF flow to benefit from surgery. On the other hand, if a patient complains about ascending neurological

Fig. 4. Kaplan-Meier analysis demonstrating progression-free sur-vival (lack of clinical recurrence) after decompression in Groups A, B, and C (p = 0.07, log-rank test).



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deficits only, he may benefit from restoration of CSF flow and control of the syrinx even if untethering is not com-pletely achievable.

For patients in Group C, pain and new motor deficits predominated the clinical picture. Their new symptoms were exclusively related to the syrinx, as the complete cord injury rendered arachnoid scarring and tethering at the injury level either clinically irrelevant or of minor sig-nificance.

Surgical Management Considering the clinical courses for patients with and

without surgery as documented in this study, surgery for posttraumatic syringomyelia should be reserved for pa-tients with progressive neurological symptoms indicating a need for early intervention.16,18,57 The first line of treat-ment should focus on restoration of normal CSF flow at the trauma level combined with untethering of the cord and duraplasty (Figs. 1 and 2). Spinal realignment or fu-sion may be added, depending on the biomechanical sta-tus at that level.27 This strategy leads to better long-term results than syrinx shunting operations.3,29,33,57

The superior results for decompression can be at-tributed to 3 reasons. First of all, the cause of the syrinx can be treated effectively with this technique. Second, the posttraumatic tethering, which may lead to a progressive myelopathy in its own right,16,18,20 can be released as well. Third, syrinx shunting procedures are associated with a high rate of long-term complications requiring frequent revisions.8,25,56 By comparison, such shunts can only ad-dress symptoms related to the syrinx but will not influ-ence the neurological problems related to posttraumatic tethering or cord compression from an arachnopathy.

For the development of the surgical technique as de-scribed in this paper, the contributions of Bernard Wil-liams have to be acknowledged. He emphasized that a posttraumatic syrinx starts at the level of the injury and is related to arachnoid scarring and CSF flow obstruction right there. So he applied his strategy of decompressions for Chiari malformation to patients with posttraumatic syringomyelia. He restored CSF flow and created a pseu-domeningocele by suturing the dura into the muscle at the injury level. At first, he combined this with a syrinx shunt.75 In part due to the first results in Los Angeles and Hannover of using this technique without syrinx shunt placement, he did not recommend additional shunts in later publications.57,76 He was a strong advocate of large pseudomeningoceles to counterbalance the pressure dis-sociations he found with his pressure recordings,73 argu-ing that any duraplasty would unnecessarily limit the subarachnoid space at the level of the previous CSF flow obstruction. Two problems, however, may arise with this technique: 1) The subarachnoid space may be contami-nated with blood products from the wound provoking an arachnoiditis that can be severe enough to cause a my-elopathy or lead to reobstruction of CSF flow. 2) The size of the pseudomeningocele may decrease with time due to bulging of muscles into this artificial CSF space.

In the 1990s several centers published reports of large case series involving patients with spinal cord injuries who had suffered late progressive neurological symptoms

attributed to posttraumatic cord tethering. Even though an intraoperative collapse of an associated syrinx was com-monly seen after untethering, these groups did not fully appreciate the effects of cord untethering and improving CSF flow for treatment of posttraumatic syringomyelia. If they observed no syrinx collapse after untethering, a syrinx shunt was placed.16,18–20,42

To obtain a sufficient CSF passage at the injury level, arachnolysis and duraplasty alone may not be sufficient. For patients with a spinal stenosis or severe kyphotic deformity it may also be required to restore the sagittal alignment of the spine.15,27,50 In fact, this alone has been shown to decrease the size of a posttraumatic syrinx in some cases.27,54 Whereas establishing a sufficient size of the spinal canal to deal with a stenosis usually provides no problem, the correction of ventral compressions and kyphotic angulations may have to involve major surgical interventions depending on the involved spinal level.58 Falci et al.18 were rather restrictive in recommending kyphectomies for patients with posttraumatic cord tether-ing. Such surgery does carry considerable risks, particu-larly in the mid- and upper thoracic spine in patients with residual cord function.

In this study, a negative effect of posttraumatic kypho-sis on postoperative outcome after decompression could not be demonstrated (Fig. 1). This may be explained by the small number of patients with severe kyphosis but may also represent the selection of patients for surgery. Surgery to restore a free CSF pathway was not recommended for patients in Group C if severe kyphotic angulation was pres-ent, and a cordectomy was suggested instead.

Alternatively, thecoperitoneal shunts have been in-troduced, which drain CSF from the subarachnoid space above the trauma level to the peritoneal cavity.40,48,62,70,71 For cavities extending into the cervical cord, ventriculo-peritoneal shunts have been used for the same purpose.51,77 However, there exists little experience concerning the optimal pressure setting for such shunts. Programmable valves may be used, but they are not designed for this purpose. Where should the valve be placed? No data exist as to how much tissue coverage may be allowed over the valve without losing the ability to change the pressure set-ting with the programming device. Low-pressure valves have also been used. In one patient in this series even a low-pressure valve provided too much pressure resistance, so eventually a valveless drain was used. This worked for a year, after which the catheter became blocked and the paraplegic patient finally agreed to a cordectomy.

For patients with a complete cord lesion, cordecto-my is a very effective form of treatment for syringomy-elia17,22,31,41,57,74 (Fig. 3). However, the psychological burden entailed by a patient’s decision to accept this operation should not be underestimated. Most patients prefer to undergo a decompression first, and this procedure does provide good results in the great majority of patients.22 Patients will accept a cordectomy if the ascending neuro-logical symptoms cannot be arrested by a decompression or shunting procedures. On the other hand, in Group C patients with severe kyphotic deformities, a cordectomy is the reasonable first choice of treatment.

In patients with a posttraumatic syrinx, distinguish-

J. Klekamp


ing between symptoms related to syringomyelia and those related to cervical degenerative disc disease may be difficult. Such degenerative changes can be a profound problem for patients confined to a wheelchair.57 In a pa-tient without radicular symptoms or neck pain, the clini-cal picture of a cervical myelopathy can be indistinguish-able from a posttraumatic syrinx or posttraumatic cord tethering. In such instances functional radiographs of the cervical spine should be evaluated carefully. If signs of hypermobility or instability are detectable, a ventral or posterior fusion should be considered. The spinal cord of a patient with syringomyelia may react to hypermobility in the cervical spine earlier and more profoundly than one would generally expect. This should also be kept in mind for patients presenting with new neurological problems after successful treatment of a syrinx.

Complications and Surgical MorbidityPostoperative complications were observed in 16%

of cases in this series, a rate similar to those reported in the literature.3,19,57,67 Surgical treatment of arachnoid scar-ring, which may encase the spinal cord from all sides, is not without risks. In patients without previous spinal cord injury (Group A) severe tethering is very unlikely. In such cases, the arachnoid pathology is almost always restricted to the posterior subarachnoid space. If sharp arachnoid dissection respects the intermediate layer of the arachnoid on the spinal cord surface, no permanent surgical morbid-ity should occur. For patients with complete cord lesions (Group C), surgery at the injury level poses no danger of further loss of neurological function. Restoring CSF flow and untethering the cord can be performed without any restrictions—even to the extent of a cordectomy—without risking additional deficits. However, surgical morbidity may be a significant problem for patients after multiple syrinx shunting attempts and those with incomplete cord injuries (Group B). It is in these patients that arachnoid dissection and untethering threaten residual spinal cord function in an area of already existing structural dam-age. The low surgical morbidity in this study (6.1%) is a consequence of the conservative approach in these cases. A free CSF pathway can almost always be created poste-riorly. However, restrictions apply for the extent of unte-thering anteriorly.

Most papers on posttraumatic syringomyelia do not report data for surgical morbidity. Ushewokunze et al.67 reported a surgical morbidity rate of 10% in their group of 40 patients treated by means of arachnolysis and dura-plasty. Falci et al.18 presented a series of 362 patients with posttraumatic cord tethering after spinal cord injury. The authors described their surgical untethering in this and a previous paper.19 Their untethering extended further ante-riorly. The dentate ligaments were cut and the cord rotated along its longitudinal axis to achieve a complete untether-ing if found necessary. They stated that 9% of patients ex-perienced a loss of motor function, 7% a loss of light touch, and 12% a loss of pinprick sensation due to these opera-tions. According to their patients’ self assessment, 11% had lost some sensory or motor function with this surgery. The lower figure determined in this study may be attributable to the more conservative strategy toward anterior untethering.

Postoperative Radiological OutcomeAnalyzing postoperative MRI studies showed a re-

duction of the syringomyelia cavity in 61% of cases (Figs. 1 and 2), while 24% remained unchanged. Reexpansions were seen in 15% (Table 5). The best results were ob-tained for patients in Group C, in whom reexpansions were exceptional events. As a consequence of the surgi-cal restrictions in patients in Group B, radiological results were considerably worse in this group.

Other investigators reported similar figures for syrinx reductions with the decompression technique as applied in this study.3,57,67 However, they did not analyze these results in relation to the severity of the original cord in-jury. Even though it is well established that a syrinx may decrease very slowly after successful restoration of CSF flow,72 several authors recommend a syringosubarachnoid shunt if the syrinx does not collapse intraoperatively after untethering the cord.18–20,42 As insertion of a catheter may also cause additional arachnoid scarring, this strategy is not recommended.

Short-Term OutcomeThe best effect of surgery was obtained for pain.19,39,47,66

However, not all types of pain respond equally to success-ful treatment of posttraumatic syringomyelia. Pain pro-voked by maneuvers such as coughing or sneezing usually improves if the syrinx regresses postoperatively. On the other hand, the response of neuropathic and dysesthetic pain is unpredictable.65 A positive effect was reported by 9 (47%) of 19 affected patients after surgery in this study irrespective of changes of the syrinx or other neurological symptoms, which is similar to other reports in the litera-ture.18,65

Even with successful reduction of syrinx size, neuro-logical deficits usually remained unchanged in this study (Table 6). Similar experiences are reported in the litera-ture.3,18,29,76 Nevertheless, 51% of patients considered their condition improved 3 months after surgery, while 41% reported an unchanged status. Given the fact that surgery was restricted to patients with progressive symptoms, this can be considered a favorable short-term result.

Long-Term Outcome of Operated PatientsAnalysis of long-term results was performed with

Kaplan-Meier statistics to account for the varying follow-up times and to determine the rate of patients experienc-ing a neurological relapse after surgery (Table 7). Sixty-one operations were performed to improve CSF flow with arachnolysis and duraplasty. Overall, 14 clinical recur-rences were encountered (representing a recurrence rate of 23%). According to Kaplan-Meier statistics, this figure indicates 5- and 10-year progression-free survival rates of 72% and 45%, respectively. Similar figures were reported by Aghakhani et al.3 in their study involving 19 patients treated in this manner. Their analysis also clearly showed significantly better results with this technique than with syrinx shunt procedures. Ushewokunze et al.67 presented a series of 40 patients, continuing Williams’ work in Bir-mingham. They used his technique first but later changed their policy regarding the handling of the dura and per-



209

formed duraplasties. Their series included only patients with complete or incomplete cord injuries. Twenty-one of 33 patients adequately studied with MRI showed a reduc-tion of the syrinx postoperatively. After 6 months, 11 of 25 patients were neurologically improved and 6 considered their status unchanged, whereas 8 demonstrated progres-sion. In the long term, 23 of 40 patients required no further operations, while 17 patients underwent subsequent proce-dures for neurological recurrences. In 9 of these 17 cases, the patients’ condition could be stabilized with additional operations. Postoperative dysesthetic pain was observed in 5 patients—possibly related to leaving the dura open in some of the authors’ earlier cases.

Other authors mentioned the number of subsequent reoperations that were necessary after arachnolysis, unte-thering, and duraplasty to comment on long-term results. Lee et al.42 observed that only 1 of 19 patients required a revision after untethering the cord without syrinx shunt-ing. In the group of 25 patients treated with shunting only, 3 patients’ condition worsened and 2 needed shunt revi-sions, while in the group treated with untethering plus shunting 33% had a clinical recurrence.

Long-term results were considerably better for pa-tients in Groups A and C than for those in Group B (Table 7; Fig. 4). This could lead one to consider syrinx shunts for this subgroup instead. However, if the data on shunted patients from the study in 199733 are compared with the results for decompression in Group B of the present study, the recurrence rates for decompressions are significantly lower (38% at 5 years postoperatively, as compared with 88% in the 1997 study; p = 0.0004, log-rank test).

Long-Term Outcome Without SurgeryThe analysis of cases in which surgery was not per-

formed clearly indicates that patients with posttraumatic syringomyelia who present in clinically stable condition should not undergo surgery. Their course appears to be rather benign for a considerable amount of time. The rates for progression-free survival for up to 10 years for this subgroup of patients who did not undergo surgery are comparable to those for surgically treated patients in Groups A and C. For patients presenting with a history of progressive symptoms, however, results in surgically treated patients in Groups A and C are better than the results in patients who refused the operation.

For patients in Group B, on the other hand, the situa-tion is more complex. The number of cases with sufficient follow-up data involving patients who did not undergo surgery despite its being recommended is too low to al-low any conclusion to be drawn about whether decom-pression would have provided a better result.

ConclusionsThis study indicates that long-term results of surgery

for posttraumatic syringomyelia have improved with the technique of arachnolysis, restoration of CSF flow, un-tethering the cord, and duraplasty compared with times when a syrinx shunt was considered the only option. But the results are still far from perfect for a significant number of patients (Fig. 4). Patients who have progres-

sive neurological signs without initial cord injuries have a very good prognosis with this type of surgery. Clini-cal recurrences were observed in only 6% in this group within 10 years. Patients with complete cord injuries and deteriorating neurological condition can always be stabi-lized. If a decompression fails, a cordectomy can arrest further neurological progression once and for all. Howev-er, problems remain for patients with syringomyelia after incomplete cord injuries (Group B in this study). Stabiliz-ing their neurological status without risking their fragile residual cord function is a real challenge. Looking at the results of this study, it remains open whether decompres-sion provided a benefit for this subgroup compared with patients who were not treated surgically. Even if the syr-inx has been controlled, residual tethering may still cause a progressive myelopathy, threatening the patient’s walk-ing abilities and sphincter function. Performing surgery on an injured spinal cord does carry significant risks. Looking at this case series, one can see that a learning curve was clearly evident. It remains to be seen whether results can be improved for this subgroup with growing experience or whether thecoperitoneal shunts are a better alternative, even though they do not address symptoms related to posttraumatic tethering.

Disclosure

The author reports no conflict of interest concerning the mate-rials or methods used in this study or the findings specified in this paper.

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Manuscript submitted October 17, 2011.Accepted May 30, 2012.Please include this information when citing this paper: pub-

lished online July 13, 2012; DOI: 10.3171/2012.5.SPINE11904.Address correspondence to: Jörg Klekamp, M.D., Department of

Neurosurgery, Christliches Krankenhaus, Danziger Strasse 2, 49610 Quakenbrück, Germany. email: [email protected].

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