Split cord malformation types I and II: a personal series of 131 patients

One-stage Spine-shortening Osteotomy Treated Severe Spinal Deformity Associated With Spinal Cord Malformations

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To evaluate the safety and efficacy of spine-shortening using 1-stage 3-column osteotomy for a severe rigid spinal deformity with a spinal cord malformation (SCM).

SUMMARY OF BACKGROUND DATA

One-stage spine-shortening osteotomy has been suggested for the treatment of a tethered spinal cord. However, the safety and efficacy of 1-stage spine-shortening osteotomy for the treatment of a severe spinal deformity with an SCM is not known.

METHODS

The records of 32 patients with a severe spinal deformity and SCM treated with spine-shortening using 3-column osteotomy from January 2010 to December 2016 were analyzed retrospectively. Intraoperative neurophysiological monitoring was used in all cases. Imaging parameters and neurological complications were analyzed to evaluate clinical safety and efficacy.

RESULTS

Spine-shortening using a 3-column osteotomy was conducted successfully in all 32 patients. The mean main coronal curve and maximum kyphotic angle were corrected from 119.8 and 119.1 degrees to 58.6 and 53.9 degrees, respectively, with the corrective rate of 51.4% and 54.3%. The mean correction loss of the major coronal curve and maximum kyphosis was 2.3 and 2.6 degrees, respectively, at a mean follow-up of 73.6 months. Intraoperative monitoring events occurred in 9 patients; of these 9 patients, 3 suffered transient SC injury, and all recovered within 1 year without suffering permanent paralysis.

CONCLUSIONS

Spine-shortening using a 3-column osteotomy seems to be safe and efficacious for treating a severe spinal deformity with an SCM. A deep understanding of the method and intensive intraoperative neuromonitoring improved the safety of this challenging and complex surgical procedure.

A Case of Neonate with Split Cord Malformation Presenting with Hypoplasia of the Left Lower Extremity

The frequency of split cord malformation (SCM) is approximately 1 in 5000 births; however, patients are rarely diagnosed with SCM in the neonatal period. Moreover, there have been no reports of SCM with hypoplasia of the lower extremities at birth. A 3-day-old girl was transferred to our hospital for a thorough examination of hypoplasia of the left lower extremity and lumbosacral abnormalities detected after birth. The spinal magnetic resonance imaging (MRI) revealed a split spinal cord in a single dural tube. Based on the MRI findings, the patient was diagnosed with SCM type II. Following discussions with the parents, pediatricians, neurosurgeons, psychologists, and social workers, we decided to perform untethering to prevent further neurological impairment after achieving a sufficient body weight. The patient was discharged on day 25 of life. Early diagnosis and intervention may improve the neurological prognosis in terms of motor function, bladder and bowel function, and superficial sensation; thus, clinicians should report infrequent findings that may lead to SCM diagnosis. SCM should be differentiated in patients with left-right differences in the appearance of the lower extremity, particularly in those with lumbosacral abnormalities.

Split cord malformation concomitant with spinal teratoma without open spinal dysraphism

PURPOSE

Split cord malformation (SCM) presenting concomitant with spinal teratoma without any open spinal dysraphism has rarely been reported in the literature. We aimed to make a systematic review and qualitative analysis of the literature about the topic and present the first case of SCM concomitant with spinal teratoma harboring papillary thyroid carcinoma (PTC) component.

METHODS

Two big search tools (Pubmed/MEDLINE) and Scopus were used. The search strategy was compatible to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). An exemplary case of ours was also presented.

RESULTS

There were 30 patients (15 pediatric and 15 adult). Female and male distribution was even. Median age of the patients was 18 years (range = 0-66 years). The most common presenting symptoms were back pain and lower limb weakness. Spinal teratoma and SCM mostly presented at thoracic/thoracolumbar region in children and lumbar region in adults. Surgical outcome was better in the children compared to the adults.

CONCLUSION

Thoracolumbar region is the most common location for such entity in children, whereas lumbar region for the adults. Surgical resection should be done as much as possible under neuromonitorization. The resected material should be evaluated thoroughly not to miss any malign pathology. Surgical outcome is better when it is done at an early age.

Adult-onset presentation of cervicothoracic split cord malformation: illustrative case

BACKGROUND

A 60-year-old female presented with a 6-month history of progressive lower limb pain, weakness, and declining mobility. She was initially diagnosed as having possible hip osteoarthritis or ligamental knee injury. She was eventually seen by a neurologist, who admitted her to a tertiary hospital with new-onset upper motor neuron signs and urinary incontinence. Magnetic resonance imaging of the whole spine revealed evidence of C7–T2 type 1 split cord malformation (SCM) necessitating urgent spinal surgery. She had an excellent outcome with intensive rehabilitation and returned to her premorbid level of function and mobility.

OBSERVATIONS

The patient presented with nonspecific symptoms, which led to multiple referrals and a significant delay in her diagnosis.

LESSONS

Clinicians should be aware of the importance of a detailed history with thorough neurological and spinal examinations.

Combined Type 1 and 2 split cord malformations, kyphoscoliosis, tethered cord, and a lipoma

Background:

Split cord malformations (SCMs) are uncommon congenital anomalies. They can be divided into Type 1 (bony septum and two separate dural sheaths) and Type 2 (fibrous septum and a single dural sheath).[1,2,4] Rarely,SCM can be associated with orthopedic anomalies (mostly seen in older children), such as scoliosis, followed by kyphosis, and/or both.[1-3] Conversely, patients with congenital scoliosis have 40% risk of congenital underlying neural deformities, with 16.3% attributed to SCM.[1,4] Those with thoracic or lumbosacral SCM may have congenital tethering lesions, predominantly consisting of intradural lipomas.[3,4] Surgery is optimally performed in two stages: first, removal of the spinal septum and untethering of the cord, and second, correction of the kyphosis, scoliosis, and/or both.[1-5]

Case Description:

In this video, a 44-year-old female initially presented after having progressively developed kyphoscoliosis since childhood. Three months before presentation, she had developed increased left lower extremity pain with hypoesthesia followed 1 month later by the onset of the left lower extremity monoplegia (0/5). The computed tomography and magnetic resonance imaging studies revealed a SCM at the L3 level with bony and membranous septum, accompanied by an intradural lipoma, and tethered cord. She underwent a two- stage procedure; first, removal of the bony and membranous septum, resection of the intradural lipoma, and untethering of the cord; second, she had correction of the kyphoscoliosis. Postoperatively, although the pain and sensory deficits improved, the left lower extremity monoplegia remained.

Conclusion:

SCM is a rare cause of spinal deformity. If left untreated, the associated neurological deficits may progress. Treatment should include a two-staged approach; first, the bony and membranous septum should be removed followed by lipoma resection and untethering the cord with adequate cord decompression, while second, a fusion may be performed to address attendant kyphoscoliosis.

Keywords:

Intradural lipoma, Kyphoscoliosis, Split cord malformation, Tethered cord

Klippel-Feil Syndrome with Cervical Diastematomyelia in an Adult with Extensive Cervicothoracic Fusions: Case Report and Review of the Literature

Split cord malformation (SCM) is a developmental disorder that is usually symptomatic and diagnosed in childhood. The majority of these lesions are in the thoracic and lumbar spine, with only 1%-3% of cases found in the cervical spine. This is a case report of a 55-year-old female patient with an unremarkable medical history who presented with neck pain. Upon workup, she was found to have extensive developmental anomalies throughout her cervical and thoracic spine, including an incidentally found type 2 SCM and multiple autofused vertebrae. There are only 6 similar studies published in the literature. There was extensive facet degeneration in her cervical spine, which was suspected to be the etiology of her neck pain. This case illustrates the rare finding of asymptomatic adult cervical SCM and the likely significance of her autofused vertebrae causing accelerated symptomatic facet spondylosis.

Posterior-Only Surgical Correction with Heavy Halo-Femoral Traction for the Treatment of Severe and Rigid Congenital Scoliosis Associated with Tethered Spinal Cord and Type II Split Cord Malformation

OBJECTIVE

To evaluate the safety and efficacy of posterior-only surgical correction with heavy halo-femoral traction for the treatment of severe and rigid congenital scoliosis (SRCS) associated with tethered spinal cord (TSC) and type II split cord malformation (SCM).

METHODS

Thirteen patients with SRCS associated with TSC and type II SCM underwent posterior-only surgical correction with heavy halo-femoral traction. The preoperative mean coronal Cobb angle was 88.87° ± 12.15°; the mean flexibility was 15.28% ± 3.88%; and the mean angle of thoracic kyphosis and lumbar lordosis was 39.63° ± 18.47° and 56.99° ± 10.02°, respectively.

RESULTS

The mean duration of surgery was 320 ± 43.64 minutes and the mean blood loss was 1422.31 ± 457.59 mL. The mean follow-up period was 24.46 ± 7.53 months. After heavy halo-femoral traction, the mean coronal Cobb angle was reduced to 59.14° ± 8.75°. After posterior-only surgical correction, postoperative mean coronal Cobb angle was further reduced to 33.85° ± 8.77°. The postoperative mean correction rate was 62.46% ± 5.04%. The postoperative mean angle of thoracic kyphosis and lumbar lordosis was 29.31° ± 6.75° and 47.79° ± 3.68°, respectively. At the final follow-up, the corrective loss rate of Cobb angle was only 0.69%. There were no significant differences between final follow-up and preoperative modified Japanese Orthopaedic Association total scores. The Scoliosis Research Society-22 total score improved at the final follow-up evaluation compared with the preoperative total score.

CONCLUSIONS

Without prophylactic neurosurgical intervention and spine-shortening osteotomy, posterior-only surgical correction with heavy halo-femoral traction could be safe and effective for the treatment of SRCS associated with TSC and type II SCM.

Split Cord Malformation Type 2 with Double Dorsal Lipoma: A Sequela or a Chance

An 11-month-old baby girl, with normal perinatal history, presented with a congenital lumbosacral swelling and a sacral dimple. Imaging revealed a split cord malformation (SCM) type 2 at L1–L3 with a lipomeningocoele extending intradurally and tethering both the hemicords, the conus was noted to be at L4. She underwent excision of the lipoma and detethering of the hemicords. Intraoperatively, the split cord was seen from L1 to L3 with an aberrant median vessel passing between the hemicords. Two lipomas were seen separately attached to each of the hemicords, the lipomas were dissected off the hemicords, and the hemicords were neurulated. The case helps revisit the unified theory proposed by Pang for SCM as well as the theory of premature disjunction in the pathogenesis of lipomeningocoele. Formation of the endomesenchymal tract splits the developing cord into two, whereas the premature detachment of neuroectoderm from the cutaneous ectoderm can lead to lipomeningocoeles. The present case is only the fourth case ever reported of an SCM type 2 with double lipoma. In the case report, we discuss the embryological basis of this condition and surgical nuances of management.

Posterior-only surgical correction with heavy halo-femoral traction for the treatment of rigid congenital scoliosis associated with split cord malformation

Background

Whether or not, prophylactic neurosurgical interventions of split cord malformation (SCM) before undertaking corrective surgery was the focus of debate. The present study was performed to evaluate the safety and efficacy of posterior-only surgical correction with heavy halo-femoral traction for the treatment of rigid congenital scoliosis (RCS) associated with SCM.

Methods

From 2011 to 2017, 24 patients suffered from RCS associated with SCM underwent posterior-only surgical correction with heavy halo-femoral traction. The apex of the deformity was lumbar (n = 9), thoracic (n = 11), and thoracolumbar (n = 4). There were 13 cases of failure of segmentation; 4 cases of failure of formation and 7 cases of mixed defects. Based on SCM classification, there were 14 patients with SCM type 1 and 10 patients with SCM type 2. The Scoliosis Research Society (SRS)-22 and modified Japanese Orthopaedic Association (mJOA) scores were assessed preoperatively and at the final follow up.

Results

The mean duration of surgery was 327.08 ± 43.99 min and the mean blood loss was 1303.33 ± 526.86 ml. The mean follow-up period was 20.75 ± 8.29 months. The preoperative mean coronal Cobb angle was 80.38° ± 13.55°; on the bending radiograph of the convex side, the mean Cobb angle was 68.91° ± 15.48°; the mean flexibility was 15.04% ± 7.11%. After heavy halo-femoral traction, the mean coronal Cobb angle was reduced to 56.89° ± 13.39°. After posterior-only surgical correction, postoperative mean coronal Cobb angle was further reduced to 32.54° ±11.33°. The postoperative mean correction rate was 60.51% ± 7.79%. At the final follow up, the corrective loss rate of Cobb angle was only 3.17%. The SRS-22 total score improved at the final follow-up evaluation compared with the preoperative SRS-22 total score. The spinal cord function was stable and there were no new neurological symptoms after correction. There were no significant differences between final follow-up and preoperative mJOA total scores.

Conclusions

Without prophylactic neurosurgical intervention and spine-shortening osteotomy, posterior-only surgical correction with heavy halo-femoral traction could be safe and effective for the treatment of RCS associated with SCM.

Split Cord Malformation: Presentation, Management, and Surgical Outcome

BACKGROUND

Split cord malformation (SCM) is a rare anomaly characterized by a split along the midline of the cord, which divides it into 2 symmetric or nonsymmetric entities. SCM surgical indications and outcomes are still debatable, the signs and symptoms are generally nonspecific and are commonly associated with other anomalies and deficits.

METHODS

We retrospectively searched the hospital database at King Abdulaziz Medical City, Riyadh, Saudi Arabia for patients with SCM between 1998 and 2018. Descriptive statistics were used to present categorical data as percentages and frequencies.

RESULTS

A total of 25 patients were included in this series. The mean age of patients at the time of diagnosis was 4.4 years. A total of 18 patients (72%) underwent surgical correction. The mean difference between the age at diagnosis and the age at correction was 7 months. All patients underwent intraoperative neurophysiologic monitoring. Postoperative complications were minimal. Cerebrospinal fluid leakage was noted in 2 patients, transient urinary retention was noted in 1 patient, and transient unilateral leg paresis was noted in 1 patient. Most patients (n = 15, 83%), were discharged within 19 days after surgery, and 81% showed improvement postoperatively. Over the long-term follow-up, none of the patients developed new urologic or neurologic deficits.

CONCLUSIONS

Most patients with SCM present during childhood. Postoperative complications after SCM corrective surgery are generally minimal, and the overall outcomes, mainly including partial or complete symptomatic improvement and/or symptom stability and hydronephrosis resolution, were favorable.

Chinese expert consensus on diagnosis and management of split cord malformation

Split cord malformation (SCM) is a neural tube defect that the spinal cord is longitudinally separated into two hemicords with individual functions, which causes severe spinal cord impairment and sensorimotor deficit. As a kind of myelodysplasia and a special type of tethered cord syndrome, SCM is not widely understood, and common issues in the diagnosis and treatment of SCM should be clarified. In this paper, the Chinese Split Cord Malformation Working Group made a consensus for SCM on embryopathogenesis and types, clinical presentations, neuroimaging assessment, indications and principle of the surgery, surgical techniques and nuances, and prognosis and follow up.

The Treatment of Severe Congenital Scoliosis Associated With Type I Split Cord Malformation: Is a Preliminary Bony Septum Resection Always Necessary?

BACKGROUND

Single-stage spine-shortening osteotomy without treating spinal cord malformations may have potential advantages for the treatment of severe congenital scoliosis (CS) with type I split spinal cord malformation (SSCM); however, the study of this technique was limited.

OBJECTIVE

To evaluate the safety and efficacy of a single-stage spine-shortening osteotomy in the treatment of severe CS associated with type I SSCM.

METHODS

A retrospective study was designed to compare 2 case series including 12 severe CS patients with type I SSCM and 26 patients with type A cord function (without spinal cord malformations, evoked potential abnormalities, and neurological dysfunctions preoperatively) treated with a single-stage spine-shortening posterior vertebral column resection (PVCR). Patient demographic, clinical, operative, and radiographic data were obtained and compared between groups.

RESULTS

The surgical procedure was successfully performed in both groups, and the patients were observed for an average of 44.9 mo (range 25-78 mo) after the initial surgery. The radiographic parameters, intraoperative data, and new neurological deficits showed no difference, while deformity angular ratio (SSCM group: control group = 16.6 ± 3.6: 20.1 ± 3.9, P = .01) and corrective rate (SSCM group: control group = 50%: 58%, P = .046) of the main curve were statistically different between groups. All of the new neurological deficits were recovered within 1 yr.

CONCLUSION

The single-stage spine-shortening PVCR with moderate correction could be applied to the treatment of CS associated with type I SSCM. This strategy can achieve safe spinal deformity correction while obviate the neurological complications brought by the detethering procedures, which merits further clinical investigation.

Management of split cord malformation in children: the Lyon experience

INTRODUCTION

Split cord malformation (SCM) is a rare congenital spinal abnormality. Clinical presentation varies. Other congenital defects can be associated. Management is surgical.

MATERIAL AND METHODS

We retrospectively reviewed all our SCM cases and reported our experience for its management. From 1990 to 2014, 37 patients were operated. Five situations lead to the diagnosis (orthopedic disorders (n = 8), orthopedic and neurological disorders (n = 16), pure neurological disorders (n = 5), no symptoms except cutaneous signs (n = 7), antenatal diagnosis (n = 1)). Scoliosis was the most common associated condition. The level of the spur was always under T7 except in one case. There were more type I (n = 22) than type II (n = 15) SCM.

RESULTS

Patients with preoperative neurological symptoms (n = 21) were improved in 71.4%. Five out of nine patients that had preoperative bladder dysfunction were improved. Eleven patients needed surgical correction of the scoliosis.

CONCLUSIONS

For us, the surgical procedure is mandatory even in case of asymptomatic discovery in order to avoid late clinical deterioration. In any case, the filum terminale need to be cut in order to untether completely the spinal cord. In case a surgical correction of a spinal deformity is needed, we recommend a two-stage surgery, for both SCM type. The SCM surgery can stop the evolution of the scoliosis and it may just need an orthopedic treatment with a brace.

Benefit of Intraoperative Neurophysiological Monitoring in a Pediatric Patient with Spinal Dysmorphism, Split Cord Malformation, and Scoliosis

Intraoperative neurophysiological monitoring (IONM) consists of a group of neurodiagnostic techniques that assess the nervous system's functional integrity during surgical operations. A retrospective analysis of a pediatric female patient was conducted who underwent 12 operations for the correction of scoliosis, tethered cord, and split spinal cord wherein IONM played an important role. From age 3 to 6, she underwent six procedures including a release of the tethered cord, resection of the filum terminale, removal of a T11-T12 bony spur, release of L3 adhesions, repair of subcutaneous meningocele, and correction of scoliosis with a vertical expandable prosthetic titanium rod (VEPTR) technique without the use of IONM. However, a multimodality IONM protocol with somatosensory evoked potentials, transcranial electrical motor evoked potentials (TCeMEP), and an electromyogram was utilized during the later procedures. At age 6 (the seventh procedure), a VEPTR expansion was performed, with loss and recovery of the lower extremity motor evoked potentials. The postoperative magnetic resonance imaging (MRI) showed a partial split cord malformation with retethering of the spinal cord. We repaired her split cord malformation and tethered cord while employing IONM. Using IONM for her operation was crucial because a sudden significant loss of TCeMEP resulted in a cancellation of the procedure; the MRI showed a thick remnant attached to the spinal cord. If the procedure was performed without IONM, we could have missed the underlying pathology, an error that may have resulted in paraplegia. We strongly recommend using IONM during high-risk surgical procedures to help significantly reduce the risk of permanent postoperative complications.

Surgical management of 142 cases of split cord malformations associated with osseous divide

OBJECTIVES

To investigate the key surgical points in treating split cord malformations associated with osseous divide and scoliosis (SCM-OD-S).

MATERIALS AND METHODS

The surgical options and methods of a total of 142 SCM-OD-S cases were retrospectively analyzed, and the surgical precautions and imaging diagnosis were also discussed.

RESULTS

The 142 patients were performed osseous divide resection plus dural sac molding, which achieved good results and no serious complication such as spinal cord and nerve injury occurred; certain symptoms such as urination-defecation disorders, muscle strength subsidence, Pes Cavus, and toe movement disorder in partial patients achieved various degrees of relief, and it also created good conditions for next-step treatment against scoliosis.

CONCLUSIONS

The diagnosis of SCM-OD mainly depended on imaging inspection, routine magnetic resonance imaging (MRI) combined with computed tomography (CT) 3D reconstruction, which can comprehensively evaluate the types and features of diastematomyelia as well as other concomitant diseases. SCM alone needed no treatment, but surgery will be the only means of treating SCM-OD. Intraoperatively removing osseous divide step-by-step, as well as carefully freeing the spinal cord and remodeling the dural sac, can lay good foundations for relieving tethered cord, improving neurological symptoms, and further scoliosis orthomorphia, thus particularly exhibiting importance for the growth and development of adolescents.

Composite split cord malformation associated with a dermal sinus tract, dermoid cyst, and epidural abscess: A case report and review of literature

Background:

Split cord malformation (SCM) is typically present at a single level but rarely, may be present at multiple levels in the spinal cord and can be associated with a wide array of lesions such as myelomeningoceles, lipomas, teratomas, and dermal sinus tracts (DSTs).

Case Description:

We describe a case of a 15-month-old female child who presented with high-grade fever and progressive motor weakness in the lower limbs. Magnetic resonance imaging revealed the presence of SCM along with an epidural abscess, DST, and dermoid cyst. The child underwent surgery for excision of DST along with removal of the dermoid cyst and drainage of epidural abscess. The postoperative course was uneventful. Elective repair of the SCM was performed 4 weeks later. The postoperative course was uneventful again.

Conclusion:

To the best of our knowledge, the combination of a composite SCM with a DST and dermoid cyst with associated epidural abscess has rarely been reported in literature.

Incidence and type of foot deformities in patients with spina bifida according to level of lesion

AIM

The previously suggested association between the incidence of high-level foot deformity and muscle imbalance is no longer supported, when evaluated independent from motor and sensory loss and level of lesion, by current studies. The purpose of this study was to evaluate the association between level of lesion and foot deformity.

METHODS

Of 545 patients, a total of 136 (272 feet) patients admitted to the spina bifida clinic between 2010 and 2014 were included in this study. Levels of all lesions were evaluated using initial operation data, the motor-sensory exams, and direct radiography. All patients were categorized into four different groups: Thoracic region (group 1), high-level lumbar-L1-2 region (group 2), mild and lower lumbar regions (L3-4-5) (group 3), and Sacral region (group 4).

RESULTS

The mean follow-up time was 34.9 months (range 8-176 months). Group 1, group 2, group 3, and group 4 included 24 (17.6%), 14 (10.3%), 19 (14%), and 79 (58.1%) patients with regards to level of lesion, respectively. The incidences of foot deformity were 85.4, 85.7, 81.5, and 50.6% in groups 1, 2, 3, and 4, respectively. Of all patients, 22% (61 feet) had clubfoot, 16% (44 feet) pes cavus, 10% (26 feet) pes valgus, 6% (17 feet) isolated equinus, 6 % (17 feet) pes calcaneus, and 5% (13 feet) metatarsus adductus. Patients without a foot deformity (81% of normal feet) usually had a lesion at the sacral level (p ≤ 0.05). On the other hand, isolated equinus (70%) and clubfoot (49%) deformities were mostly observed in spinal lesions (p > 0.05). The incidence of pes calcaneus, pes valgus, and adductus deformities inclined as the lesion level decreased (p > 0.05).

CONCLUSION

In this study, it was concluded that foot deformities were directly related to the level of lesion. The comparison of higher and lower level lesions revealed that the types of foot deformity differed significantly. The muscle imbalance due to spina bifida was not sufficient to explain the pathology. On the other hand, the level of spinal lesion is an important factor for the type of deformity.

Safety and Efficacy of One-stage Spinal Osteotomy for Severe and Rigid Congenital Scoliosis Associated with Split Spinal Cord Malformation

STUDY DESIGN

Retrospective clinical study.

OBJECTIVE

To retrospectively evaluate the safety and efficacy of one-stage spinal osteotomy in the treatment of severe and progressive congenital scoliosis (CS) associated with split spinal cord malformation (SSCM).

SUMMARY OF BACKGROUND DATA

For severe and rigid spinal deformity, spinal osteotomies are often advocated for correcting the deformity. However, the safety and efficacy of one-stage spinal osteotomy in the treatment of severe and rigid CS with SSCM have been unclear thus far.

METHODS

Patients were treated by one-stage spinal osteotomy between September 2007 and June 2011 in our hospital. The clinical records were reviewed for demographic and radiographical data, operative time, intraoperative blood loss, blood transfusion, perioperative complications, and functional outcomes.

RESULTS

There were 18 females and 11 males with an average age of 15.5 ± 3.6 years (range, 12-28 yr). Spinal cord was longitudinally split by a bony spur in 11 patients (type I SSCM) and by a fibrous band in 18 patients (type II SSCM). Patients were observed for a minimum of 24 months after initial surgical treatment with an average follow-up of 43.0 ± 17.1 months (range 24-68 mo) from September 2007 to June 2013. The mean operative time and average blood loss of type ISSCM was significantly greater than those of type II SSCM (P < 0.05). The major curve was corrected from an average of 97.2°± 17.8° to 35.7°± 15.9°, a mean correction rate of 64.3% ± 11.0%. The average loss of correction at final follow-up was 2.9% for major curves. The overall complication rate was 24.1%, including transient neurological deterioration in 3 patients, cerebrospinal fluid leakage in 2 patients, urinary tract infection in 1 patient and pleural rupture in 1 patient.

CONCLUSION

Relative to multistage corrective surgery, one-stage spinal osteotomy is effective for the correction of severe CS and SSCM without increasing the rate of surgical complications. However, surgical treatment of type I SSCM does require more operating time and blood loss.

LEVEL OF EVIDENCE

4.

Cutting filum terminale is very important in split cord malformation cases to achieve total release

AIM

Split cord malformations (SCMs) are rare congenital anomalies of the vertebrae and the spinal cord. Tethered cord syndrome (TCS) is a clinical condition of various origins that arises from tension on the spinal cord. Radiographic findings may include and/or associate split cord malformations and the other neural tube defects. However, the spinal cord can even be tethered by a filum terminale with normal appearance and normal level conus medullaris in magnetic resonance imaging (MRI). The aim of our study is to show whether SMC patients with normal or abnormal MRI findings had all histological abnormal filum terminale and also to show that the standard SCM repairing operation without cutting filum will not achieve total release.

MATERIAL AND METHODS

We have reviewed 33 SCM patients between July 2005 and December 2013. They were operated by adding untethering procedure of filum terminale following standard surgical intervention, and a part of the filum was taken for histopathological examination even though MRI did not show the presence of abnormality of filum terminale.

RESULTS

We found that abnormal filum terminale with a normal appearance may had dense collagen fibers, wide and numerous capillaries, and hyaline formation, while normal filum terminale is a mixture of collagen fibers and blood vessels. We did not obtain positive Verhoeff elastic fiber staining. The elastic fibers had disappeared in all fila terminalia, except control cadaver group.

CONCLUSION

Our results showed that all fila of SCM patients had loss of elastic fibers and increased of hyalinization, which means loss of elasticity of filum terminale. Less severe traction may remain asymptomatic in childhood and present with neurological dysfunction later in life. For this reason, surgical procedure of SCM patients including releasing of filum terminale seems more beneficial for the patients and be better for long term.