The role of occipital condyle and atlas anomalies on occipital cervical fusion outcomes in Chiari malformation type I with syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Congenital anomalies of the atlanto-occipital articulation may be present in patients with Chiari malformation type I (CM-I). However, it is unclear how these anomalies affect the biomechanical stability of the craniovertebral junction (CVJ) and whether they are associated with an increased incidence of occipitocervical fusion (OCF) following posterior fossa decompression (PFD). The objective of this study was to determine the prevalence of condylar hypoplasia and atlas anomalies in children with CM-I and syringomyelia. The authors also investigated the predictive contribution of these anomalies to the occurrence of OCF following PFD (PFD+OCF).

METHODS

The authors analyzed the prevalence of condylar hypoplasia and atlas arch anomalies for patients in the Park-Reeves Syringomyelia Research Consortium database who underwent PFD+OCF. Condylar hypoplasia was defined by an atlanto-occipital joint axis angle (AOJAA) ≥ 130°. Atlas assimilation and arch anomalies were identified on presurgical radiographic imaging. This PFD+OCF cohort was compared with a control cohort of patients who underwent PFD alone. The control group was matched to the PFD+OCF cohort according to age, sex, and duration of symptoms at a 2:1 ratio.

RESULTS

Clinical features and radiographic atlanto-occipital joint parameters were compared between 19 patients in the PFD+OCF cohort and 38 patients in the PFD-only cohort. Demographic data were not significantly different between cohorts (p > 0.05). The mean AOJAA was significantly higher in the PFD+OCF group than in the PFD group (144° ± 12° vs 127° ± 6°, p < 0.0001). In the PFD+OCF group, atlas assimilation and atlas arch anomalies were identified in 10 (53%) and 5 (26%) patients, respectively. These anomalies were absent (n = 0) in the PFD group (p < 0.001). Multivariate regression analysis identified the following 3 CVJ radiographic variables that were predictive of OCF occurrence after PFD: AOJAA ≥ 130° (p = 0.01), clivoaxial angle < 125° (p = 0.02), and occipital condyle-C2 sagittal vertical alignment (C-C2SVA) ≥ 5 mm (p = 0.01). A predictive model based on these 3 factors accurately predicted OCF following PFD (C-statistic 0.95).

CONCLUSIONS

The authors' results indicate that the occipital condyle-atlas joint complex might affect the biomechanical integrity of the CVJ in children with CM-I and syringomyelia. They describe the role of the AOJAA metric as an independent predictive factor for occurrence of OCF following PFD. Preoperative identification of these skeletal abnormalities may be used to guide surgical planning and treatment of patients with complex CM-I and coexistent osseous pathology.

Os odontoideum: database analysis of 260 patients regarding etiology, associated abnormalities, and literature review

Introduction

Since the first description of os odontoideum in 1886, its origin has been debated. Numerous case series and reports show both a possible congenital origin and origin from the secondary to craniovertebral junction (CVJ) trauma. We conducted a detailed analysis of 260 surgically treated cases to document the initial symptoms, age groups, radiographic findings, and associated abnormalities, aiming to enhance the confirmation of the etiology. A literature search (1970-2022) was performed to correlate our findings.

Methods and materials

A total of 260 patients underwent surgical management of a referral database of 520 cases (1978-2022). All patients were examined by plain radiography and myelotomography as needed until 1984, and since then, CT and MRI have been employed. History of early childhood (aged below 6 years) CVJ trauma was investigated, including obtaining emergency department's initial radiographs from the referral and subsequent follow-up. Associated radiographic and systemic abnormalities were noted, and the atlas development was followed.

Results

The age of the patients ranged from 4 to 68 years, mostly between 10 and 20 years. There were 176 males and 86 females. Orthotopic os odontoideum was identified in 24 patients, and 236 patients had dystopic os odontoideum. Associated abnormalities were found in 94 of 260 patients, with 73 exhibiting syndromic abnormalities and 21 having Chiari I malformation. Two sets of twins had spondyloepiphyseal dysplasia. Of 260 patients, 156 experienced early childhood trauma /. Among these, 54 initially presented with normal radiographs but later demonstrated anterior atlas hypertrophy. In addition, a smaller posterior C1 arch was observed, leading to the development of os odontoideum. Two children had initial CVJ trauma as documented by MRI, with subsequent classical findings of os odontoideum and atlas changes. Syndromic patients had an earlier presentation. The literature reviewed confirms the multifactorial etiology.

Conclusions

The early presentation and associated abnormalities (such as Down syndrome, Klippel-Feil syndrome, Chiari I malformation, spondyloepiphyseal dysplasia, Morquio syndrome, and others) along with case reports documenting familial, hereditary, and twin presentations strongly support a congenital origin. Likewise, surgical complications are more prevalent in syndromic patients (40%) compared to 15% in other cases, as reported in the literature. The documentation of normal odontoid in early childhood trauma cases followed by the later development of os odontoideum provides evidence supporting trauma as an etiological factor. This process also involves vascular changes in both the atlas and the formation of os odontoideum. Associated abnormalities exhibit an earlier presentation and are only seen in cases with a non-traumatic origin.

Surgical outcomes and risk factors for recurrence of myxopapillary ependymoma: a single-center experience

OBJECTIVE

Myxopapillary ependymomas (MPEs) are low-grade, well-circumscribed tumors that often involve the conus medullaris, cauda equina, or filum terminale. They account for up to 5% of all tumors of the spine and 13% of spinal ependymomas, with a peak incidence between 30 and 50 years of age. Because of the rarity of MPEs, their clinical course and optimal management strategy are not well defined, and long-term outcomes remain difficult to predict. The objective of this study was to review long-term clinical outcomes of spinal MPEs and identify factors that may predict tumor resectability and recurrence.

METHODS

Pathologically confirmed cases of MPE at the authors' institution were identified and medical records were reviewed. Demographics, clinical presentation, imaging characteristics, surgical technique, follow-up, and outcome data were noted. Two groups of patients-those who underwent gross-total resection (GTR) and those who underwent subtotal resection (STR)-were compared using the Mann-Whitney U-test for continuous and ordinal variables and the Fisher exact test for categorical variables. Differences were considered statistically significant at p ≤ 0.05.

RESULTS

Twenty-eight patients were identified, with a median age of 43 years at the index surgery. The median postoperative follow-up duration was 107 months (range 5-372 months). All patients presented with pain. Other common presenting symptoms were weakness (25.0%), sphincter disturbance (21.4%), and numbness (14.3%). GTR was achieved in 19 patients (68%) and STR in 9 (32%). Preoperative weakness and involvement of the sacral spinal canal were more common in the STR group. Tumors were larger and spanned more spinal levels in the STR group compared with the GTR cohort. Postoperative modified McCormick Scale grades were significantly higher in the STR cohort compared with the GTR group (p = 0.00175). Seven of the 9 STR patients (77.8%) underwent reoperation for recurrence at a median of 32 months from the index operation, while no patients required reoperation after GTR, for an overall reoperation rate of 25%.

CONCLUSIONS

Findings of this study emphasize the importance of tumor size and location-particularly involvement of the sacral canal-in determining resectability. Reoperation for recurrence was necessary in 78% of patients with subtotally resected tumors; none of the patients who underwent GTR required reoperation. Most patients had stable neurological status postoperatively.

MR documented craniocervical ligamentous injury at age 18 months: delayed formation of OS odontoideum. Complex management issues. Case-based review

OBJECTIVE

There are two separate theories regarding the genesis of os odontoideum: congenital and post-traumatic. Trauma documentation in the past has been the presence of a normal odontoid process at the time of initial childhood injury and subsequent development of the os odontoideum. True MR documentation of craniocervical injury in early childhood and subsequent os odontoideum formation has been very rare.

METHODS

An 18-month-old sustained craniocervical ligamentous injury documented on MRI with transient neurological deficit. Chiari I abnormality was also recorded. Subsequent serial imaging of craniocervical region showed the formation of os odontoideum and instability. He became symptomatic from the os odontoideum and the Chiari I abnormality. The patient underwent decompression and intradural procedure for Chiari I abnormality and occipitocervical fusion. Postoperative course was complicated by the failure of fusion and redo. He later required transoral ventral medullary decompression. He recovered.

RESULTS

This is an MR documented craniocervical ligamentous injury with sequential formation of os odontoideum with accompanying changes in the atlas. Despite a subsequent successful dorsal occipitocervical fusion, he became symptomatic requiring transoral decompression.

CONCLUSIONS

Os odontoideum here is recognized as a traumatic origin with the presence of congenital Chiari I abnormality as a separate entity. The changes of the anterior arch of C1 as well as the os formation were serially documented and give credence to blood supply changes in the os and atlas as a result of the trauma. The recognized treatment of dorsal occipitocervical fusion failed in this case requiring also a ventral decompression of the medulla.

Ventriculus terminalis cyst in an infant: a case report

BACKGROUND

Filar cysts are frequently found on neonatal ultrasound and are physiologically involuting structures with natural resolution. Hence, there has been no previous histologic correlation. Ventriculus terminalis is a focal central canal dilation in the conus medullaris and usually not clinically significant. Extra-axial cyst at the conus-filum junction connected to ventriculus terminalis is extremely rare, especially when associated with tethered lipomatous filum terminale and with progressive cyst enlargement.

CASE PRESENTATION

A Caucasian female neonate with abnormal gluteal cleft had ventriculus terminalis cyst with an extra-axial cyst at the conus-filar junction and taut lipomatous filum on ultrasound examination and magnetic resonance imaging. This persisted at 6-month follow up imaging. In light of the nonresolving extra-axial mass and thick taut lipomatous filum, the child underwent L1-L3 osteoplastic laminectomies. The extra-axial cyst expanded after bony decompression and furthermore on dural opening; visualized on ultrasound. It communicated with the central canal and was documented with intraoperative photomicrographs. It was excised and filum sectioned. Histological immunostaining of the cyst wall showed neuroglial and axonal elements. The child did well without deficits at 4-year follow up with normal urodynamics.

CONCLUSION

Progression dilation of ventriculus terminalis and extra-axial conofilar cyst with tethered lipomatous filum will likely progress to clinical significance and require surgical intervention. The embryologic basis for this pathology is discussed, with literature review.

Complications and outcomes of posterior fossa decompression with duraplasty versus without duraplasty for pediatric patients with Chiari malformation type I and syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

The aim of this study was to determine differences in complications and outcomes between posterior fossa decompression with duraplasty (PFDD) and without duraplasty (PFD) for the treatment of pediatric Chiari malformation type I (CM1) and syringomyelia (SM).

METHODS

The authors used retrospective and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM1-SM who received PFD or PFDD and had at least 1 year of follow-up data. Preoperative, treatment, and postoperative characteristics were recorded and compared between groups.

RESULTS

A total of 692 patients met the inclusion criteria for this database study. PFD was performed in 117 (16.9%) and PFDD in 575 (83.1%) patients. The mean age at surgery was 9.86 years, and the mean follow-up time was 2.73 years. There were no significant differences in presenting signs or symptoms between groups, although the preoperative syrinx size was smaller in the PFD group. The PFD group had a shorter mean operating room time (p < 0.0001), fewer patients with > 50 mL of blood loss (p = 0.04), and shorter hospital stays (p = 0.0001). There were 4 intraoperative complications, all within the PFDD group (0.7%, p > 0.99). Patients undergoing PFDD had a 6-month complication rate of 24.3%, compared with 13.7% in the PFD group (p = 0.01). There were no differences between groups for postoperative complications beyond 6 months (p = 0.33). PFD patients were more likely to require revision surgery (17.9% vs 8.3%, p = 0.002). PFDD was associated with greater improvements in headaches (89.6% vs 80.8%, p = 0.04) and back pain (86.5% vs 59.1%, p = 0.01). There were no differences between groups for improvement in neurological examination findings. PFDD was associated with greater reduction in anteroposterior syrinx size (43.7% vs 26.9%, p = 0.0001) and syrinx length (18.9% vs 5.6%, p = 0.04) compared with PFD.

CONCLUSIONS

PFD was associated with reduced operative time and blood loss, shorter hospital stays, and fewer postoperative complications within 6 months. However, PFDD was associated with better symptom improvement and reduction in syrinx size and lower rates of revision decompression. The two surgeries have low intraoperative complication rates and comparable complication rates beyond 6 months.

Pediatric cervical kyphosis in the MRI era (1984-2008) with long-term follow up: literature review

OBJECTIVE

Cervical kyphosis is rare in the pediatric population. It may be syndromic or acquired secondary to laminectomy, neoplasia, or trauma. Regardless, this should be avoided to prevent progressive spinal deformity and neurological deficit. Long-term follow-up is needed to evaluate fusion status, spine growth, potential instability, and neurological function.

METHODS AND MATERIALS

A retrospective review of 27 children (6 months to 16 years) with cervical kyphotic deformity was performed and limited to the MRI era until 2008, to provide a long-term follow-up after which complex instrumentation was available. There were 27 patients, 19 syndromic (average age 5.36 years), and 8 non-syndromic (average age 14 years). Syndromes encountered were spondyloepiphyseal dysplasia (SED) 4, spondylometaphyseal dysplasia 1, unnamed collagen abnormality syndrome 1, osteogenesis imperfecta (OI) 2, Aarskog syndrome 1, Weaver syndrome 1, Larsen syndrome 1, multiple cervical level disconnection syndrome 1, Klippel-Feil 3, congenital absence of C2 pars 4. Non-syndromic cases; 2 with neurofibromatosis (NF1) and prevertebral tumors, fibromatosis 1, spontaneous kyphosis 1, and postlaminectomy 4. Factors considered were age, pathology, flexibility on cervical spine dynamic films, reduction with traction and spinal cord compression. Patients with flexible kyphosis underwent dorsal fixation. Children with non-flexible ventral compression/kyphosis had crown halo traction. Irreducible kyphosis had ventral decompression and fusion as well as dorsal fusion. Eleven of 19 syndromic children with flexible and reducible kyphosis underwent dorsal fixation alone. Four of 8 non-syndromic (2 NF1) needed ventral and dorsal approaches.

RESULTS

The preoperative deformity (global and local Cobb angles) as well as neurological status improved. Growth during follow-up was not impaired, and we did not encounter instability or junctional kyphosis. The only complications were seen in syndromic patients. One patient with SED showed delayed cantilever bending of the ventral fusion mass requiring reoperation, and 1 other OI child had left C5 and C6 nerve root weakness after anterior C4 and C5 decompression which resolved over 1 year. One child with SED developed cervicothoracic junction scoliosis 18 years later after thoracic scoliosis surgery.

CONCLUSIONS

Syndromic pathology presented early with neurological dysfunction and 24% had rigid kyphosis. An attempt at traction/reduction was successful as in Tables 1 and 2. The majority exhibited long-term improvement in kyphosis and function. A treatment algorithm and literature review is presented. Table 1 Motor function of the modified Japanese Orthopedic Association (JOA) score in children [24, 37] Score Upper extremity •Unable to move hands or feed oneself 0 •Can move hands; unable to eat with spoon 1 •Able to eat with spoon with difficulty 2 •Able to use spoon; clumsy with buttoning 3 •Healthy; no dysfunction 4 Lower extremity •Unable to sit or stand 0 •Unable to walk without cane or walker 1 •Walks independently on level floor but needs support on stairs 2 •Capable to walking, clumsy 3 •No dysfunction 4 Table 2 Pediatric cervical kyphosis-preoperative evaluations Case ID, year presented Age Sex Diagnosis Presentation Imaging Apex Cobb angle degree Reducibility Preop traction Syndromic #1 2003 4 years M SED Progressive quadriparesis Bladder incontinence Severe C2-4 kyphosis with cord compression C3-4 85° No No #2 2001 3 years M SED Progressive quadriparesis C2-3 kyphosis. No dorsal C2. Buckled cord C2-3 25° No No Recurrent weakness after recovery 2 years later Kyphosis at fusion site C2-3 33° No No #3 1997 13 years M SED Neck pain. Hand weakness. Thoracic scoliosis C1-3 kyphosis Os odontoideum C2-3 30° Yes No #4 2006 6 years F SED Tingling in hands Bladder incontinence Deformed C2 body and odontoid C1-2 instability C2-3 27° Yes No #5 1997 4 years M SMD Quadriparesis. Previous C2-3 kyphosis with O-C3 dorsal fusion elsewhere Fixed C1-2 dislocation. C2-3 kyphosis. O-C4 fusion C2 35° Partial Yes 4 days #6 2007 13 years F Syndromic collagen abnormality Neck pain. Leg length discrepancies. T-L scoliosis. Quadriparesis Bilateral C2 and partial C3 spondylolysis C-T levoscoliosis C2-3 35° Partial Yes 4 days #7 2003 14 years F Osteogenesis imperfecta (OI) Only able to use right upper extremity C3-5 kyphosis. Canal diameter 4 mm at C4 C4 25° No No #8 1989 3 years F OI - Bruck's syndrome Quadriparesis age 9 months. Had C1-C3 posterior decompression and fusion elsewhere Progressive kyphosis Worse weakness Bend in fusion C1-2 40° No No #9 1996 11 years M Aarskog syndrome Neck pain with limited neck motion Cervical myelopathy Psychomotor delay C4-5 spondylolysis C5-6 kyphosis C5 30° No Yes 3 days #10 1989 3½ years F Weaver syndrome Quadriparesis age 2 years. Elsewhere C1-C3 dorsal rib fusion and wires Fusion failure C2-3 subluxation Cord compression C2-3 3° Yes Yes 1 day #11 1986 11 years F Larsen syndrome Neck pain in extension Quadriparesis C2-3 kyphosis. Deformed bodies C2-5 Os odontoideum C1-2 instability C2-3 28° Yes Yes 1 day #12 1996 5 years M Multilevel cervical disconnect syndrome Horner pupil on right Small right arm Quadriparesis C4, C5 vertebral bodies behind C5 C5 body in canal Left vertebral artery in C5 body C4-5 35° No No #13 1985 3 years F Klippel-Feil Neck pain. Weak hands Atlas assimilation C3-4 kyphosis No posterior bony arches C3, C4 C3-4 40° Yes No #14 1994 3 years F Klippel-Feil Unable to sit. Floppy. Quadriparesis C2-3 kyphosis No posterior arches C2-3 and L4 C2-3 45° Yes No #15 1993 11 months F Tuberous sclerosis Spondylolysis C2 Salam seizures Quadriparesis No pars C2 C2-3 kyphosis C2-3 30° Yes No #16 1998 2 years M C2 spondylolysis Quadriparesis, arms worse than legs C2 spondylolysis C2-3 kyphosis C2-3 35° Yes No #17 1998 6 months M C2 spondylolysis Failure to thrive Apneic spells Weak in arms after endoscopy C2-3 kyphosis No C2 lamina Cord compression C3-4 on MRI C2-3 45° Yes No #18 1990 4 years F C2 spondylolysis Developmental delay Quadriparesis C2 spondylolysis C2-3 kyphosis C3 45° Yes No #19 1994 4 years F Klippel-Feil No posterior C2 Torticollis age 6 mo Quadriparesis C2-3 kyphosis No posterior arch C2 Fused C3-4 bodies C2-3 45° Yes No Non-syndromic #20 1996 15 years M NF1. Ventral prevertebral plexiform neurofibroma Neck pain Weak arms Cervical myelopathy C4-5 kyphosis Cord draped over C4-5 Enhanced prevertebral tumor C4-5 60° Partial Yes 4 days #21 1996 6 years M NF1 Age 6 mo had C1-3 laminectomies elsewhere Progressive kyphosis Quadriparesis C3-5 plexiform neurofibromas C2-4 kyphosis C3-4 45° No No #22 1993 11 years M "Fibromatosis" Neck pain Gag ↓ Right hemiparesis C2 body and odontoid curved dorsally C2-3 kyphosis C2 40° No Yes 3 days #23 2007 13 F Mid-cervical kyphosis Neck pain Unable to move neck C3-4 kyphosis C3-4 45° Yes Halo vest elsewhere 6 weeks Repeat traction on referral #24 1998 12 years M Chiari I Syringohydromyelia Difficulty swallowing Quadriparesis Previous posterior fossa and C1-3 decompression Basilar invagination C3-4 kyphosis C3-4 50° Yes Halo traction 3 days #25 1994 16 years M Chiari I. SHM Difficult speech Quadriparesis Previous posterior fossa and C1-4 laminectomies C3-4 kyphosis Basilar invagination C3-4 55° Yes Halo traction 3 days #26 2002 11 years M Chordoma C3-5 Initial quadriparesis improved after posterior decompression then worse Dorsal and lateral tumor C3-4 C3-4 20° Yes Traction 3 days #27 2006 13 years M C4 lamina Aneurysmal bone cyst Neck and shoulder pain C4 laminectomy for tumor resection Worse 4 months later C4-5 kyphosis C3-4 40° Yes No Table 3 Pediatric cervical kyphosis-postoperative evaluations Case ID Diagnosis Treatment-operation Complication PO orthosis F/U time Fusion status Preop Cobb Postop Cobb Preop JOA Postop JOA Comments Syndromic #1 SED Crown halo traction 1. Median mandibular glossotomy. Resection C2-3 bodies with rib graft fusion 2. Dorsal O-C3 rib graft fusion None Halo vest 3 months Soft collar 3 months 8 years Complete anterior and posterior fusion 85° 10° 2 8 Complete neurological recovery #2 SED Crown halo traction 1. Median mandibular glossotomy. C2-4 corpectomies. C2-5 anterior rib graft fusion Recurrent weakness 2 years s later Halo vest 3 months 2 years Fused 25° 20° 4 5 T. scoliosis. Cardiac abnormalities. Walking then quadriparesis Redo ventral resection and C1-4 iliac bone graft Worsening quadriparesis Minerva brace 1 year 18 years Fused 33° 15° 3 5 Much improved in 6 months #3 SED Crown halo traction Dorsal O-C4 fusion with loop and rib graft None Miami J collar 3 months 10 years Fused 30° 13° 4 7 Works in bookstore #4 SED Crown halo traction Dorsal O-C3 fusion with loop and rib graft 4 years later developed C-T scoliosis after T. scoliosis surgery Miami J collar 3 months 14 years Fused 27° 5° 5 7 C-T scoliosis developed after thoracic scoliosis correction #5 SMD Crown halo traction Transoral C2 odontoid resection None Minerva brace 6 months 20 years No from preop status 35° 10° 1 4 In wheelchair. Works as programmer #6 Collagen abnormality Crown halo traction C2-5 ACDF C2-5 plate with C3-4 lag screws Junctional kyphosis 7 years later after scoliosis correction Miami J collar 6 weeks 12 years Fused 36° 5° 4 7 Abnormal vertebral arteries. Thoracic outlet syndrome May-Thurner syndrome #7 OI Crown halo traction C3-5 corpectomies C2-6 Orion plate with iliac crest graft None Soft collar 4 years Fused 25° 30° 1 5 Restrictive lung disease. Multiple fractures Expired #8 OI - Bruck syndrome 1. Redo C1-2 dorsal rib graft fusion No change Molded Minerva brace 4 years Fused 40° 35° 3 4 Increased weakness age 7 2. 11 years age anterior C3-7 decompression and plate C3-7 Worsening left deltoid and biceps function Molded Minerva brace 30 years Fused 52° 34° 3 5 Lives alone. Wheelchair. Computer technologist Uses hands well #9 Aarskog syndrome Crown halo traction C2-6 anterior cervical fusion with iliac crest graft None Molded Minerva brace 20 years Fused 30° 14° 4 7 Works on a farm. No myelopathy. Syndrome in family #10 Weaver syndrome Crown halo traction Redo C1-4 dorsal rib graft fusion None Miami J collar 2 years Fused 3° 10° 2 5 Neuroblastoma age 3 months. Chemotherapy Stable #11 Larsen syndrome Crown halo traction O-C5 dorsal fusion None Halo vest 6 weeks Miami J 3 months 6 years Fused 28° 10° 3 7 Doing well #12 Multilevel cervical disconnect syndrome Crown halo traction C5 corpectomy C4-6 iliac bone fusion anteriorly Dorsal C4-6 fusion None Halo vest 3 months 5 years Fused 35° 5° 3 7 Persistent Horner pupil #13 Klippel-Feil Crown halo traction C2-6 posterior rib graft fusion None Halo vest 3 months 19 years Fused 40° 12° 3 7 Hearing loss Genitourinary abnormalities Sprengel's deformity #14 Klippel-Feil Crown halo C2-5 dorsal rib graft fusion None Halo vest 3 months 35 years Fused 45° 10° 1 6 Hearing loss Genitourinary abnormalities #15 Tuberous sclerosis Spondylolysis C2 C1-4 dorsal interlaminar rib fusion None Halo vest 3 months 6 years Fused 30° 5° 1 6 Psychomotor delay #16 C2 spondylolysis C1-4 dorsal interlaminar fusion None Halo vest 3 months 4 years Fused 35° 10° 2 6 Recovered full function in one year #17 C2 spondylolysis Tracheostomy Molded cervicothoracic brace None Mold brace 4 years 6 years Formed C2 posterior arches 45° 20° 1 3 Reformed C2 at 4 years on CT Parents did not wish surgery #18 C2 spondylolysis Intraoperative traction C1-3 dorsal rib graft fusion None Neck brace 4 months 8 years Fused 45° 12° 2 5 Developed C2 posterior elements #19 Klippel-Feil Intraoperative traction O-C4 fusion with rib graft None Molded brace 6 months 1 years Fused O-C2 dorsally 45° 16° 1 4 Able to sit and use hands Non-syndromic #20 NF1 Resection of ventral tumor C3-6 C4-5 corpectomies; C4-5 iliac graft; C3-7 Orion plate None Halo vest 6 weeks 14 years Fused 60° 15° 3 7 Recovered in 6 weeks. Works on a farm #21 NF1 Intraoperative traction Resect prevertebral tumor C2-5 kyphectomies; C2-6 anterior fusion iliac crest None Halo vest 3 months 2 years Fused 45° 20° 3 5 Initial C1-3 decompression done elsewhere #22 Fibromatosis 1. Transoral C2 decompression 2. Dorsal O-C3 fusion with loop None Brace 3 months 12 years Fused 40° 12° 4 6 Age 2 years had neck mass resected. Diagnosis "fibromatosis" #23 Mid-cervical kyphosis Traction C2-5 lateral mass fusion with screws, rods and rib grafts Worse after removal of initial traction Brace 3 months 8 years Fused 45° 15° 7 8 Doing well #24 Chiari I SHM Intraoperative traction O-C5 rib graft fusion None Halo vest 3 months 21 years Fused 50° 7° 2 6 Facets atrophied C2, C3 at surgery #25 Chiari I SHM Intraoperative traction O-C5 dorsal fusion with loop and rib None Miami J brace 4 months 22 years Fused 55° 10° 3 6 Facets atrophied C2-4 at surgery #26 Chordoma C3-4 1. Dorsal lateral C3-6 fusion 2. C2-5 anterior fusion with iliac bone None Miami J brace 6 months 18 years Fused 20° 12° 5 8 Weak in hands after initial surgery elsewhere #27 ABC tumor C4 Anterior C3-5 fusion with plate and bone None Miami J brace 4 weeks 12 years Fused 40° 15° 5 8 No recurrence SED spondyloepiphyseal dysplasia, SMD spondylometaphyseal dysplasia, JOA Japanese Orthopedic Association, MRI magnetic resonance imaging, SHM syringohydromyelia, NF1 neurofibromatosis type 1, f/u follow up, OI osteogenesis imperfecta, CT computed tomography, JK junctional kyphosis.

Socioeconomic and demographic factors in the diagnosis and treatment of Chiari malformation type I and syringomyelia

OBJECTIVE

The goal of this study was to assess the social determinants that influence access and outcomes for pediatric neurosurgical care for patients with Chiari malformation type I (CM-I) and syringomyelia (SM).

METHODS

The authors used retro- and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM-I and SM who received surgical treatment and had at least 1 year of follow-up data. Race, ethnicity, and insurance status were used as comparators for preoperative, treatment, and postoperative characteristics and outcomes.

RESULTS

A total of 637 patients met inclusion criteria, and race or ethnicity data were available for 603 (94.7%) patients. A total of 463 (76.8%) were non-Hispanic White (NHW) and 140 (23.2%) were non-White. The non-White patients were older at diagnosis (p = 0.002) and were more likely to have an individualized education plan (p < 0.01). More non-White than NHW patients presented with cerebellar and cranial nerve deficits (i.e., gait ataxia [p = 0.028], nystagmus [p = 0.002], dysconjugate gaze [p = 0.03], hearing loss [p = 0.003], gait instability [p = 0.003], tremor [p = 0.021], or dysmetria [p < 0.001]). Non-White patients had higher rates of skull malformation (p = 0.004), platybasia (p = 0.002), and basilar invagination (p = 0.036). Non-White patients were more likely to be treated at low-volume centers than at high-volume centers (38.7% vs 15.2%; p < 0.01). Non-White patients were older at the time of surgery (p = 0.001) and had longer operative times (p < 0.001), higher estimated blood loss (p < 0.001), and a longer hospital stay (p = 0.04). There were no major group differences in terms of treatments performed or complications. The majority of subjects used private insurance (440, 71.5%), whereas 175 (28.5%) were using Medicaid or self-pay. Private insurance was used in 42.2% of non-White patients compared to 79.8% of NHW patients (p < 0.01). There were no major differences in presentation, treatment, or outcome between insurance groups. In multivariate modeling, non-White patients were more likely to present at an older age after controlling for sex and insurance status (p < 0.01). Non-White and male patients had a longer duration of symptoms before reaching diagnosis (p = 0.033 and 0.004, respectively).

CONCLUSIONS

Socioeconomic and demographic factors appear to influence the presentation and management of patients with CM-I and SM. Race is associated with age and timing of diagnosis as well as operating room time, estimated blood loss, and length of hospital stay. This exploration of socioeconomic and demographic barriers to care will be useful in understanding how to improve access to pediatric neurosurgical care for patients with CM-I and SM.

Cognitive and Psychological Functioning in Chiari Malformation Type I Before and After Surgical Decompression - A Prospective Cohort Study

BACKGROUND

Chiari Malformation Type I (CM-I) is defined as cerebellar tonsil displacement more than 5 mm below the foramen magnum. This displacement can alter cerebrospinal fluid flow at the cervicomedullary junction resulting in Valsalva-induced headaches and syringomyelia and compress the brainstem resulting in bulbar symptoms. However, little is known about cognitive and psychological changes in CM-I.

OBJECTIVE

To prospectively assess cognitive and psychological performance in CM-I and determine whether changes occur after surgical decompression.

METHODS

Blinded evaluators assessed symptomatic CM-I patients ages ≥18 with a battery of neuropsychological and psychological tests. Testing was conducted preoperatively and 6 to 18 mo postoperatively. Data were converted to Z-scores based on normative data, and t-tests were used to analyze pre-post changes.

RESULTS

A total of 26 patients were included, with 19 completing both pre- and post-op cognitive assessments. All patients had resolution of Valsalva-induced headaches and there was improvement in swallowing dysfunction (P < .0001), ataxia (P = .008), and sleep apnea (P = .021). Baseline performances in visual perception and construction (z = -1.11, P = .001) and visuospatial memory (z = -0.93, P = .002) were below average. Pre-post comparisons showed that CM-I patients had stable cognitive and psychological functioning after surgery, without significant changes from preoperative levels.

CONCLUSION

CM-I patients had below average performance in visuospatial and visuoconstructional abilities preoperatively. Prospective longitudinal data following surgery demonstrated improved neurologic status without any decline in cognition or psychological functioning. Routine pre- and postoperative formal neuropsychological assessment in CM-I patients help quantify cognitive and behavioral changes associated with surgical decompression.

Fourth ventricle roof angle as a measure of fourth ventricle bowing and a radiographic predictor of brainstem dysfunction in Chiari malformation type I

OBJECTIVE

Chiari malformation type I (CM-I) is a congenital and developmental abnormality that results in tonsillar descent 5 mm below the foramen magnum. However, this cutoff value has poor specificity as a predictor of clinical severity. Therefore, the authors sought to identify a novel radiographic marker predictive of clinical severity to assist in the management of patients with CM-I.

METHODS

The authors retrospectively reviewed 102 symptomatic CM-I (sCM-I) patients and compared them to 60 age-matched normal healthy controls and 30 asymptomatic CM-I (aCM-I) patients. The authors used the fourth ventricle roof angle (FVRA) to identify fourth ventricle "bowing," a configuration change suggestive of fourth ventricle outlet obstruction, and compared these results across all three cohorts. A receiver operating characteristic (ROC) curve was used to identify a predictive cutoff for brainstem dysfunction. Binary logistic regression was used to determine whether bowing of the fourth ventricle was more predictive of brainstem dysfunction than tonsillar descent, clival canal angle, or obex position in aCM-I and sCM-I patients.

RESULTS

The FVRA had excellent interrater reliability (intraclass correlation 0.930, 95% CI 0.905-0.949, Spearman r2 = 0.766, p < 0.0001). The FVRA was significantly greater in the sCM-I group than the aCM-I and healthy control groups (59.3° vs 41.8° vs 45.2°, p < 0.0001). No difference was observed between aCM-I patients and healthy controls (p = 0.347). ROC analysis indicated that an FVRA of 65° had a specificity of 93% and a sensitivity of 50%, with a positive predictive value of 76% for brainstem dysfunction. FVRA > 65° was more predictive of brainstem dysfunction (OR 5.058, 95% CI 1.845-13.865, p = 0.002) than tonsillar herniation > 10 mm (OR 2.564, 95% CI 1.050-6.258, p = 0.039), although increasing age was also associated with brainstem dysfunction (OR 1.045, 95% CI 1.011-1.080, p = 0.009). A clival canal angle < 140° (p = 0.793) and obex below the foramen magnum (p = 0.563) had no association with brainstem dysfunction.

CONCLUSIONS

The authors identified a novel radiographic measure, the FVRA, that can be used to assess fourth ventricular bowing in CM-I and is more predictive of brainstem dysfunction than tonsillar herniation. The FVRA is easy to measure, has excellent interrater variability, and can be a reliable universal radiographic measure. The FVRA will be useful in further describing CM-I radiographically and clinically by identifying patients more likely to be symptomatic as a result of brainstem dysfunction.

Extradural decompression versus duraplasty in Chiari malformation type I with syrinx: outcomes on scoliosis from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is common in patients with Chiari malformation type I (CM-I)-associated syringomyelia. While it is known that treatment with posterior fossa decompression (PFD) may reduce the progression of scoliosis, it is unknown if decompression with duraplasty is superior to extradural decompression.

METHODS

A large multicenter retrospective and prospective registry of 1257 pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for patients with scoliosis who underwent PFD with or without duraplasty.

RESULTS

In total, 422 patients who underwent PFD had a clinical diagnosis of scoliosis. Of these patients, 346 underwent duraplasty, 51 received extradural decompression alone, and 25 were excluded because no data were available on the type of PFD. The mean clinical follow-up was 2.6 years. Overall, there was no difference in subsequent occurrence of fusion or proportion of patients with curve progression between those with and those without a duraplasty. However, after controlling for age, sex, preoperative curve magnitude, syrinx length, syrinx width, and holocord syrinx, extradural decompression was associated with curve progression > 10°, but not increased occurrence of fusion. Older age at PFD and larger preoperative curve magnitude were independently associated with subsequent occurrence of fusion. Greater syrinx reduction after PFD of either type was associated with decreased occurrence of fusion.

CONCLUSIONS

In patients with CM-I, syrinx, and scoliosis undergoing PFD, there was no difference in subsequent occurrence of surgical correction of scoliosis between those receiving a duraplasty and those with an extradural decompression. However, after controlling for preoperative factors including age, syrinx characteristics, and curve magnitude, patients treated with duraplasty were less likely to have curve progression than patients treated with extradural decompression. Further study is needed to evaluate the role of duraplasty in curve stabilization after PFD.

Occipital-Cervical Fusion and Ventral Decompression in the Surgical Management of Chiari-1 Malformation and Syringomyelia: Analysis of Data From the Park-Reeves Syringomyelia Research Consortium

BACKGROUND

Occipital-cervical fusion (OCF) and ventral decompression (VD) may be used in the treatment of pediatric Chiari-1 malformation (CM-1) with syringomyelia (SM) as adjuncts to posterior fossa decompression (PFD) for complex craniovertebral junction pathology.

OBJECTIVE

To examine factors influencing the use of OCF and OCF/VD in a multicenter cohort of pediatric CM-1 and SM subjects treated with PFD.

METHODS

The Park-Reeves Syringomyelia Research Consortium registry was used to examine 637 subjects with cerebellar tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and at least 1 yr of follow-up after their index PFD. Comparisons were made between subjects who received PFD alone and those with PFD + OCF or PFD + OCF/VD.

RESULTS

All 637 patients underwent PFD, 505 (79.2%) with and 132 (20.8%) without duraplasty. A total of 12 subjects went on to have OCF at some point in their management (PFD + OCF), whereas 4 had OCF and VD (PFD + OCF/VD). Of those with complete data, a history of platybasia (3/10, P = .011), Klippel-Feil (2/10, P = .015), and basilar invagination (3/12, P < .001) were increased within the OCF group, whereas only basilar invagination (1/4, P < .001) was increased in the OCF/VD group. Clivo-axial angle (CXA) was significantly lower for both OCF (128.8 ± 15.3°, P = .008) and OCF/VD (115.0 ± 11.6°, P = .025) groups when compared to PFD-only group (145.3 ± 12.7°). pB-C2 did not differ among groups.

CONCLUSION

Although PFD alone is adequate for treating the vast majority of CM-1/SM patients, OCF or OCF/VD may be occasionally utilized. Cranial base and spine pathologies and CXA may provide insight into the need for OCF and/or OCF/VD.

Tethered spinal cord syndrome in adults in the MRI era: recognition, pathology, and long-term objective outcomes

OBJECTIVE

Tethered cord syndrome (TCS) has been well described in pediatric patients. Many recent reports of TCS in adult patients have grouped retethering patients with newly diagnosed ones without separately analyzing each entity and outcome. The authors reviewed their experience of newly diagnosed adult TCS patients to identify and explore TCS misdiagnosis, recognition, subtype pathology, and individual objective outcomes.

METHODS

This study included 24 adult patients (20 female and 4 male) who fit the criteria of being newly diagnosed and aged 20 years and older (age range 20-77 years). Preexisting dermal sinus was present in 6 patients, hypertrichosis in 5, skin tag/cleft/dimple and fatty subcutaneous masses in 5, scoliosis in 2, and neurological abnormalities in 4 patients. The pathology consisted of TCS with taut filum in 8 patients, conus lipoma with TCS in 7, diastematomyelia in 7, and cervical cord tethering in 2 patients. Of the 24 study patients, nondermatomal low-back or perineal pain occurred in 19 patients, bladder dysfunction in 21, and motor, sensory, and reflex abnormalities in 21 patients. Aggravating factors were repeated stretching, multiple pregnancies, heavy lifting, and repeated bending. Urological evaluation included bladder capacity, emptying, postvoid residuals, detrusor function, pelvic floor electromyography (EMG), bladder sensitivity, and sphincter EMG, which were repeated at 6 months and 1 year postoperatively. The follow-up was 1 to 30 years. Detailed postoperative neurological findings and separate patient outcome evaluations were recorded. Four of the 24 patients did not have an operation.

RESULTS

Resolution of pain occurred in 16 of the 19 patients reporting low-back or perineal pain. Motor and sensory complaints resolved in 17 of 20 patients. Regarding bladder dysfunction, in the 20 patients with available data, bladder function returned to normal in 12 patients, improved in 3 patients, and was unchanged in 5 patients. If the symptom duration was less than 6-8 months, there was recovery of all parameters of pain, bladder dysfunction, and neurological deficit, and recovery from hyperreflexia matched that from neurological deficit. Fifteen patients were employed preoperatively and returned to work, and an additional 3 others who were unable to work preoperatively were able to do so postoperatively.

CONCLUSIONS

Most adults with newly diagnosed TCS have unrecognized neurocutaneous abnormalities and neurological deficits. The triad of nondermatomal sacral or perineal pain, bladder dysfunction, and neurological deficit should not be confused with hip or degenerative lumbosacral disease. Addressing the primary pathology often leads to successful results.

Dural augmentation approaches and complication rates after posterior fossa decompression for Chiari I malformation and syringomyelia: a Park-Reeves Syringomyelia Research Consortium study

OBJECTIVE

Posterior fossa decompression with duraplasty (PFDD) is commonly performed for Chiari I malformation (CM-I) with syringomyelia (SM). However, complication rates associated with various dural graft types are not well established. The objective of this study was to elucidate complication rates within 6 months of surgery among autograft and commonly used nonautologous grafts for pediatric patients who underwent PFDD for CM-I/SM.

METHODS

The Park-Reeves Syringomyelia Research Consortium database was queried for pediatric patients who had undergone PFDD for CM-I with SM. All patients had tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and ≥ 6 months of postoperative follow-up after PFDD. Complications (e.g., pseudomeningocele, CSF leak, meningitis, and hydrocephalus) and postoperative changes in syrinx size, headaches, and neck pain were compared for autograft versus nonautologous graft.

RESULTS

A total of 781 PFDD cases were analyzed (359 autograft, 422 nonautologous graft). Nonautologous grafts included bovine pericardium (n = 63), bovine collagen (n = 225), synthetic (n = 99), and human cadaveric allograft (n = 35). Autograft (103/359, 28.7%) had a similar overall complication rate compared to nonautologous graft (143/422, 33.9%) (p = 0.12). However, nonautologous graft was associated with significantly higher rates of pseudomeningocele (p = 0.04) and meningitis (p < 0.001). The higher rate of meningitis was influenced particularly by the higher rate of chemical meningitis (p = 0.002) versus infectious meningitis (p = 0.132). Among 4 types of nonautologous grafts, there were differences in complication rates (p = 0.02), including chemical meningitis (p = 0.01) and postoperative nausea/vomiting (p = 0.03). Allograft demonstrated the lowest complication rates overall (14.3%) and yielded significantly fewer complications compared to bovine collagen (p = 0.02) and synthetic (p = 0.003) grafts. Synthetic graft yielded higher complication rates than autograft (p = 0.01). Autograft and nonautologous graft resulted in equal improvements in syrinx size (p < 0.0001). No differences were found for postoperative changes in headaches or neck pain.

CONCLUSIONS

In the largest multicenter cohort to date, complication rates for dural autograft and nonautologous graft are similar after PFDD for CM-I/SM, although nonautologous graft results in higher rates of pseudomeningocele and meningitis. Rates of meningitis differ among nonautologous graft types. Autograft and nonautologous graft are equivalent for reducing syrinx size, headaches, and neck pain.

MRI characteristics and resectability in spinal cord glioma

OBJECTIVE

The histopathology of intramedullary spinal cord tumors (IMSCT) can be suspected from the MRI features and characteristics. Ultimately, the confirmation of diagnosis requires surgery. This retrospective study addresses MRI features including homogeneity of enhancement, margination, and associated syrinx in intramedullary astrocytomas (IMA) and ependymomas (IME) that assist in diagnosis and predict resectability of these tumors.

METHODS

Single-center retrospective analysis of IMA and IME cases since 2005 extracted from the departmental registry/electronic medical records post IRB approval (IRB 201,710,760). We compared imaging findings (enhancement, margination, homogeneity, and associated syrinxes) between tumor types and examined patient outcomes.

RESULTS

There were 18 IME and 21 IMA. On preoperative MRI, IME was favored to have homogenous enhancement (OR 1.8, p = 0.0001), well-marginated (p < 0.0001, OR 0.019 [95 % CI 0.002-0.184]), and associated syrinx (p = 0.015, OR 0.192 [95 % CI 0.049-0.760]). Total excision, subtotal excision, and biopsy were performed in 12, 5, and 1 patients in the IME cohort, respectively. In the IMA group, tumors were heterogeneous and poorly marginated in 20 of the 21 patients. Total excision, subtotal excision, and biopsy were undertaken in 2, 13, and 6 patients, respectively. The success of excision was predicted by MRI, with a significant difference in the extent of resection between IME and IMA (X2 = 14.123, p = 0.001). In terms of outcome, ordinal regression analysis showed that well-margined tumors and those with homogeneous enhancement were associated with a better postoperative McCormick score. Extent of resection had statistically significant survival (p = 0.026) and recurrence-free survival (p = 0.008) benefits.

CONCLUSION

The imaging characteristics of IME and IMA have meaningful clinical significance. Homogeneity, margination, and associated syrinxes in IME can predict resectability and complexity of surgery.

CONGENITAL CERVICAL TETHERED SPINAL CORD IN ADULTS: RECOGNITION, SURGICAL TECHNIQUE AND LITERATURE REVIEW. CASE SERIES

OBJECTIVE

Recognition of congenital tethered cervical cord in adults and literature review.

METHODS

Retrospective review of adult onset tethered cervical cord patients (more than 20 years of age).

RESULTS

Three adults were identified; 2 female and 1 male with an average age of 47 years. The presenting symptoms were neck pain with restricted movement (3), quadriparesis (2), sensory changes (2). Hyperreflexia was present in all these. Bony abnormalities were mainly bifid cervical spinous processes (3) and Klippel-Feil abnormalities in 1. The neurocutaneous stigmata was seen in 2. MRI revealed "limited dorsal myeloschisis" in all 3 patients. The dorsal aspect of the cervical cord extruded into the tract leading to the surface.

CONCLUSIONS

Neurocutaneous stigmata should not be considered benign. A missed clinical diagnosis was apparent in all 3 patients; 2 of whom underwent surgery with excellent results. MRI can identify the abnormal cervical cord protruding towards the "sinus tract" and allow planning to avert injury to the spinal cord during release.

Current management of juvenile idiopathic arthritis affecting the craniovertebral junction

PURPOSE

Craniovertebral instability is a rare and serious problem. While previously treated surgically, better understanding of disease processes has permitted the field to move towards conservative management. Juvenile idiopathic arthritis (JIA) is one cause of pediatric craniovertebral instability. Early recognition and institution of appropriate medical therapy and bracing in a multidisciplinary fashion is critical to avoid long-term instability, joint abnormalities, or morbid surgical procedures. We seek to highlight cases of this rare problem and provide a principled approach to management decisions.

METHODS

We review 6 cases that have presented over the last 6 years and highlight 3 cases in particular regarding craniovertebral instability as a presentation of JIA. We reviewed the clinical records and radiographic features with particular emphasis of the stability of the craniovertebral junction.

RESULTS

Age range of the subjects was from 5 to 12. All patients presented with neck pain and abnormal head rotation. Four of the patients responded to medical management and/or cervical bracing with no long-term sequelae or instability. Two patients had refractory rotary subluxation, one that responded to manual reduction under pharmacological paralysis and bracing; the other had an incompetent transverse ligament requiring surgical reduction and fixation.

CONCLUSIONS

Neck pain and abnormal head rotation in an older child is rare finding but should prompt suspicion as a manifestation of JIA to the general pediatrician or initial provider. Appropriate serologic studies and MRI studies with contrast at the craniovertebral junction is necessary for evaluation. Early institution of medical management and cervical bracing under a multidisciplinary team of pediatric rheumatology and neurosurgery is key to avoiding surgical intervention and long-term abnormalities at the craniovertebral junction.

Factors associated with syrinx size in pediatric patients treated for Chiari malformation type I and syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Factors associated with syrinx size in pediatric patients undergoing posterior fossa decompression (PFD) or PFD with duraplasty (PFDD) for Chiari malformation type I (CM-I) with syringomyelia (SM; CM-I+SM) are not well established.

METHODS

Using the Park-Reeves Syringomyelia Research Consortium registry, the authors analyzed variables associated with syrinx radiological outcomes in patients (< 20 years old at the time of surgery) with CM-I+SM undergoing PFD or PFDD. Syrinx resolution was defined as an anteroposterior (AP) diameter of ≤ 2 mm or ≤ 3 mm or a reduction in AP diameter of ≥ 50%. Syrinx regression or progression was defined using 1) change in syrinx AP diameter (≥ 1 mm), or 2) change in syrinx length (craniocaudal, ≥ 1 vertebral level). Syrinx stability was defined as a < 1-mm change in syrinx AP diameter and no change in syrinx length.

RESULTS

The authors identified 380 patients with CM-I+SM who underwent PFD or PFDD. Cox proportional hazards modeling revealed younger age at surgery and PFDD as being independently associated with syrinx resolution, defined as a ≤ 2-mm or ≤ 3-mm AP diameter or ≥ 50% reduction in AP diameter. Radiological syrinx resolution was associated with improvement in headache (p < 0.005) and neck pain (p < 0.011) after PFD or PFDD. Next, PFDD (p = 0.005), scoliosis (p = 0.007), and syrinx location across multiple spinal segments (p = 0.001) were associated with syrinx diameter regression, whereas increased preoperative frontal-occipital horn ratio (FOHR; p = 0.007) and syrinx location spanning multiple spinal segments (p = 0.04) were associated with syrinx length regression. Scoliosis (HR 0.38 [95% CI 0.16-0.91], p = 0.03) and smaller syrinx diameter (5.82 ± 3.38 vs 7.86 ± 3.05 mm; HR 0.60 [95% CI 0.34-1.03], p = 0.002) were associated with syrinx diameter stability, whereas shorter preoperative syrinx length (5.75 ± 4.01 vs 9.65 ± 4.31 levels; HR 0.21 [95% CI 0.12-0.38], p = 0.0001) and smaller pB-C2 distance (6.86 ± 1.27 vs 7.18 ± 1.38 mm; HR 1.44 [95% CI 1.02-2.05], p = 0.04) were associated with syrinx length stability. Finally, younger age at surgery (8.19 ± 5.02 vs 10.29 ± 4.25 years; HR 1.89 [95% CI 1.31-3.04], p = 0.01) was associated with syrinx diameter progression, whereas increased postoperative syrinx diameter (6.73 ± 3.64 vs 3.97 ± 3.07 mm; HR 3.10 [95% CI 1.67-5.76], p = 0.003), was associated with syrinx length progression. PFD versus PFDD was not associated with syrinx progression or reoperation rate.

CONCLUSIONS

These data suggest that PFDD and age are independently associated with radiological syrinx improvement, although forthcoming results from the PFDD versus PFD randomized controlled trial (NCT02669836, clinicaltrials.gov) will best answer this question.

Differences and characteristics of symptoms by tumor location, size, and degree of spinal cord compression: a retrospective study on 53 surgically treated, symptomatic spinal meningiomas

OBJECTIVE

The differences in symptoms of spinal meningiomas have rarely been discussed from the perspective of tumor characteristics. The main purpose of this paper was to define the differences, if any, in symptoms in patients with spinal meningiomas with respect to tumor size, location, and degree of spinal cord compression. The authors also sought the threshold of spinal cord compression that causes motor weakness.

METHODS

The authors conducted a retrospective study of 53 cases of spinal meningiomas that were surgically treated from 2013 to 2018. Symptoms related to the tumor were classified as motor weakness, sensory disturbance, pain, and bowel/bladder dysfunction. Based on MR images, tumor location was classified by spinal level and by its attachment to the dura mater. Tumor dimensions were also measured. Occupation ratios of the tumors to the spinal canal and degree of spinal cord flattening were sought from the axial MR images that showed the highest degree of spinal cord compression.

RESULTS

Motor weakness and sensory disturbance were significantly more common in thoracic spine meningiomas than in cervical spine meningiomas (p < 0.001 and p = 0.013, respectively), while pain was more common in meningiomas at the craniovertebral junction (p < 0.001). The attachment, height, width, depth, and volume of the tumor showed no significant difference irrespective of the presence or absence of each symptom. In cases of motor weakness and sensory disturbance, occupation ratios and spinal cord flattening ratios were significantly larger. However, these ratios were significantly smaller in the presence of pain. Multivariate logistic regression analysis revealed that occupation ratio independently contributed to motor weakness (OR 1.14, p = 0.035) and pain (OR 0.925, p = 0.034). Receiver operating characteristic curve analysis suggested that occupation ratio with a value of 63.678% is the threshold for the tumor to cause motor weakness.

CONCLUSIONS

The study showed the difference in clinical presentation of spinal meningiomas by spinal level, occupation ratio, and spinal cord flattening ratio. An occupation ratio of approximately 64% could be utilized as the threshold value of tumor growth to cause motor weakness. Tumor growth in the cervical spine might cause pain symptoms before causing motor weakness. The relationship between the tumor and its symptomatology should be discussed with respect to tumor size relative to the surrounding spinal canal.

Multidisciplinary care for a patient with syndromic craniosynostosis: A case report with 20 years of special care

AIM

The functional and structural complexities accompanying syndromic craniosynostosis make dental care for these patients particularly challenging. We report a case of long-term care for a syndromic craniosynostosis patient. The objective of this report is to introduce special care guidance and clinical recommendation, so that oral health care providers, as key members of a multidisciplinary care team, can provide optimal diagnosis, treatment, and management for the patient with syndromic craniosynostosis.

CASE REPORT

The patient of this case report had a medical history of syndromic craniosynostosis involving multiple comorbidities. Over the past 20 years, a multidisciplinary care team has successfully treated the patient. Dental and medical procedures that the patient has received include cranial surgeries, prophylactic dental care, caries control, growth hormone therapy, comprehensive orthodontic treatment in conjunction with orthognathic surgeries, and plastic surgery.

CONCLUSION

Oral health care providers can play essential roles in multidisciplinary care for patients with craniosynostosis by understanding the patients' unique oral health conditions and dentofacial deformities. To provide optimal oral health care in a multidisciplinary team, clear communication between the members of the care team is crucial.

Fourth Ventricle Enlargement in Chiari Malformation Type I

OBJECTIVE

How Chiari malformation type I (CM-I) affects posterior fossa brain structures and produces various symptoms remains unclear. The fourth ventricle is surrounded by critical structures required for normal function. The foramen of Magendie can be obstructed in CM-I; therefore, fourth ventricle changes may occur. To test this hypothesis, we assessed fourth ventricle volume in CM-I compared with healthy controls.

METHODS

Using our database from 2007-2016, we studied 72 patients with CM-I and 30 age-matched healthy control subjects. Fourth and lateral ventricle volumes and posterior fossa volumes (PFV) were assessed and correlated with clinical signs and symptoms. Statistical analysis was performed.

RESULTS

Patients with CM-I had larger fourth ventricle volumes compared with control subjects (1.31 vs. 0.95 mL; P = 0.012). There were no differences in lateral ventricle volume or PFV. CM-I fourth ventricle volume was associated with tonsillar descent (P = 0.030). CM-I fourth ventricle volume variance was larger than healthy controls (F_71,29 = 8.33; P < 0.0001). Patients with CM-I with severe signs and symptoms had a significantly larger fourth ventricle than patients with CM-I with mild signs and symptoms (1.565 vs. 1.015 mL; P = 0.0002).

CONCLUSIONS

The fourth ventricle can be enlarged in CM-I independent of lateral ventricle size and is associated with greater tonsillar descent. Most importantly, fourth ventricle enlargement was associated with a worse clinical and radiographic presentation independent of PFV. Fourth ventricle enlargement can affect critical structures and may be a mechanism contributing to symptoms unexplained by tonsil descent. Fourth ventricle enlargement is a useful adjunct in assessing CM-I.

Radiological and clinical predictors of scoliosis in patients with Chiari malformation type I and spinal cord syrinx from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is frequently a presenting sign of Chiari malformation type I (CM-I) with syrinx. The authors' goal was to define scoliosis in this population and describe how radiological characteristics of CM-I and syrinx relate to the presence and severity of scoliosis.

METHODS

A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°).

RESULTS

Based on available imaging of patients with CM-I and syrinx, 260 of 825 patients (31%) had a clear diagnosis of scoliosis based on radiographs or coronal MRI. Forty-nine patients (5.9%) did not have scoliosis, and in 516 (63%) patients, a clear determination of the presence or absence of scoliosis could not be made. Comparison of patients with and those without a definite scoliosis diagnosis indicated that scoliosis was associated with wider syrinxes (8.7 vs 6.3 mm, OR 1.25, p < 0.001), longer syrinxes (10.3 vs 6.2 levels, OR 1.18, p < 0.001), syrinxes with their rostral extent located in the cervical spine (94% vs 80%, OR 3.91, p = 0.001), and holocord syrinxes (50% vs 16%, OR 5.61, p < 0.001). Multivariable regression analysis revealed syrinx length and the presence of holocord syrinx to be independent predictors of scoliosis in this patient cohort. Scoliosis was not associated with sex, age at CM-I diagnosis, tonsil position, pB-C2 distance (measured perpendicular distance from the ventral dura to a line drawn from the basion to the posterior-inferior aspect of C2), clivoaxial angle, or frontal-occipital horn ratio. Average curve magnitude was 29.9°, and 37.7% of patients had a left thoracic curve. Older age at CM-I or syrinx diagnosis (p < 0.0001) was associated with greater curve magnitude whereas there was no association between syrinx dimensions and curve magnitude.

CONCLUSIONS

Syrinx characteristics, but not tonsil position, were related to the presence of scoliosis in patients with CM-I, and there was an independent association of syrinx length and holocord syrinx with scoliosis. Further study is needed to evaluate the nature of the relationship between syrinx and scoliosis in patients with CM-I.

Spinal arachnoid cysts in adults: diagnosis and management. A single-center experience

OBJECTIVEAdult spinal arachnoid cysts (SACs) are rare entities of indistinct etiology that present with pain or myelopathy. Diagnosis is made on imaging studies with varying degrees of specificity. In symptomatic cases, the standard treatment involves surgical exploration and relief of neural tissue compression. The aim of this study was to illustrate features of SACs in adults, surgical management, and outcomes.METHODSThe authors searched medical records for all SACs in adults in the 10-year period ending in December 2016. Radiology and pathology reports were reviewed to exclude other spine cystic disorders. Recurrent or previously treated patients were excluded. Demographic variables (age, sex) and clinical presentation (symptoms, duration, history of infection or trauma, and examination findings) were extracted. Radiological features were collected from radiology reports and direct interpretation of imaging studies. Operative reports and media were reviewed to accurately describe the surgical technique. Finally, patient-reported outcomes were collected at every clinic visit using the SF-36.RESULTSThe authors' search identified 22 patients with SACs (mean age at presentation 53.5 years). Seventeen patients were women, representing an almost 3:1 sex distribution. Symptoms comprised back pain (n = 16, 73%), weakness (n = 10, 45%), gait ataxia (n = 11, 50%), and sphincter dysfunction (n = 4, 18%). The mean duration of symptoms was 15 months. Seven patients (32%) exhibited signs of myelopathy. All patients underwent preoperative MRI; in addition, 6 underwent CT myelography. SACs were located in the thoracic spine (n = 17, 77%), and less commonly in the lumbar spine (n = 3, 14%) and cervical/cervicothoracolumbar region (n = 2, 9%). Based on imaging findings, the cysts were interpreted as intradural SACs (n = 11, 50%), extradural SACs (n = 6, 27%), or ventral spinal cord herniation (n = 2, 9%); findings in 3 patients (14%) were inconclusive. Nineteen patients underwent surgical treatment consisting of laminoplasty in addition to cyst resection (n = 13, 68%), ligation of the connecting pedicle (n = 4, 21%), or fenestration/marsupialization (n = 2, 11%). Postoperatively, patients were followed up for an average of 8.2 months (range 2-30 months). Postoperative MRI showed complete resolution of the SAC in 14 of 16 patients. Patient-reported outcomes showed improvement in SF-36 parameters. One patient suffered a delayed wound infection.CONCLUSIONSIn symptomatic patients with imaging findings suggestive of spinal arachnoid cyst, surgical exploration and complete resection is the treatment of choice. Treatment is usually well tolerated, carries low risks, and provides the best chances for optimal recovery.

Resection of a Pediatric Intramedullary Spinal Cord Tumor: 2-Dimensional Operative Video

This video is a case presentation and demonstration of surgical approach to a pediatric intramedullary spinal cord tumor (IMSCT). IMSCT can be associated with significant morbidity and aggressive resection is associated with more favorable long-term outcome. A 13-yr-old male presented to clinic for evaluation of rapidly progressive scoliosis to the left. A contrasted MRI revealed expansion of the spinal cord with edema from approximately T3 to T9 and an enhancing lesion at T6-7 associated with a small cyst. On neurological exam, the patient had good strength throughout, but decreased sensation in the T7-12 dermatomes and decreased deep tendon reflexes in his lower extremities. The procedure included T5 to T8 osteoplastic laminectomies and IMSCT resection followed by spinal reconstruction. Intraoperative ultrasound was used to verify the tumor's location and somatosensory and motor evoked potentials were monitored throughout the procedure. Intraoperative consultation with neuropathology suggested the mass was likely pilocytic astrocytoma; therefore, it was aggressively debulked using microsurgical techniques including an ultrasonic aspirator. There was a plane between the tumor and spinal cord white matter allowing for a gross total resection. Postoperatively the patient had good strength throughout and sensation was intact except for continued numbness of the anterior thigh bilaterally. Immediate postoperative MRI demonstrated complete resection of the tumor without residual enhancement and the patient was ultimately discharged home on postoperative day 8. Follow-up imaging remained stable at 2 mo and the patient continued to do well neurologically. All patient identifiers were removed from the presented material, thus, patient consent was not obtained.

Autologous cervical fascia duraplasty in 123 children and adults with Chiari malformation type I: surgical technique and complications

OBJECT Techniques for combined extradural and intradural decompression with expansile duraplasty for Chiari malformation type I (CM-I) have been well described, with various allogenic and autologous materials used for duraplasty. However, the approach and surgical technique used for duraplasty in our treatment of CM-I and developed by the senior author in the 1990s has not been described. METHODS A prospective database was initiated in March 2003 to denote the use of cervical fascia for duraplasty and incorporate an ongoing detailed record of complications during the surgical treatment of children and adults with CM-I with and without syringomyelia. A total of 389 surgeries for CM-I were performed on 379 patients from March 2003 to June 2016. A total of 123 posterior procedures were performed on 123 patients in which both a posterior fossa extradural and intradural decompression with duraplasty (extra-intradural) was performed. In this paper the authors describe the surgical technique for harvesting and using cervical fascia for duraplasty in the surgical treatment of CM-I and analyze and discuss complications from a prospective database spanning 2003-2016. RESULTS The authors found that cervical fascia can be harvested in patients of all ages (2-61 years old) without difficulty, and it provides a good substitute for dura in creating an expansile duraplasty in patients with CM-I. Cervical fascia is an elastic-like material with a consistency that allows for a strong watertight closure. Harvesting the cervical fascia graft does not require any further extension of the incision superiorly or inferiorly to obtain the graft. Complications were uncommon in this study of 123 children and adults. The risk of any type of complication (aseptic meningitis, CSF leak, pseudomeningocele, infection, development of hydrocephalus, and need for ventriculoperitoneal shunt) for the 78 patients in the pediatric age group was 0%. The risk of complication in the adult group was 6.7% (1 patient with aseptic meningitis and 2 patients with CSF leak). CONCLUSIONS Autologous cervical fascia is easy to obtain in patients of all ages and provides an effective material for duraplasty in the treatment of CM-I. Complications from the combination of both an extradural and intradural decompression with autologous cervical fascia duraplasty are uncommon.

Syringobulbia in pediatric patients with Chiari malformation type I

OBJECTIVE Syringobulbia (SB) is a rare entity, with few cases associated with Chiari malformation type I (CM-I) in the pediatric population. The authors reviewed all pediatric cases of CM-I-associated SB managed at their institution in order to better understand the presentation, treatment, and surgical outcomes of this condition. METHODS A prospectively maintained institutional database of craniovertebral junction abnormalities was analyzed to identify all cases of CM-I and SB from the MRI era (i.e., after 1984). The authors recorded presenting symptoms, physical examination findings, radiological findings, surgical treatment strategy, intraoperative findings, and outcomes. SB cases associated with tumors, infections, or type II Chiari malformations were excluded. RESULTS The authors identified 326 pediatric patients with CM-I who were surgically treated. SB was identified in 13 (4%) of these 326 patients. Headache and neck pain were noted in all 13 cases. Cranial nerve abnormalities were common: vagus and glossopharyngeal nerve dysfunction was the most frequent observation. Other cranial nerves affected included the trigeminal, abducens, and hypoglossal nerves. Several patients exhibited multiple cranial nerve palsies at presentation. Central sleep apnea was present in 6 patients. Syringomyelia (SM) was present in all 13 patients. SB involved the medulla in all cases, and extended rostrally into the pons and midbrain in 2 patients; in 1 of these 2 cases the cavity extended further rostrally to the cerebrum (syringocephaly). SB communicated with the fourth ventricle in 7 of the 13 cases. All 13 patients were treated with posterior fossa decompression with intradural exploration to ensure CSF egress out of the fourth ventricle and through the foramen magnum. The foramen of Magendie was found to be occluded by an arachnoid veil in 9 cases. Follow-up evaluation revealed that SB improved before SM. Cranial nerve palsies regressed in 11 of the 13 patients, and SB improved in all 13. CONCLUSIONS The incidence of SB in our surgical series of pediatric patients with CM-I was 4%, and all of these patients had accompanying SM. The SB cavity involved the medulla in all cases and was found to communicate with the fourth ventricle in 54% of cases. Posterior fossa decompression with intradural exploration and duraplasty is an effective treatment for these patients.

Intracranial extradural arachnoid cyst in a child

INTRODUCTION

Arachnoid cysts are benign developmental anomalies of arachnoid membrane origin that can occur anywhere along the neuro-axis. They are believed to develop from the splitting or duplication of the arachnoid membrane by CSF that is trapped by a ball-valve mechanism. Intracranial arachnoid cysts have only been described as intradural lesions while spinal arachnoid cysts can be both intradural or extradural.

CASE REPORT

After an extensive literature review, we report the first case of an intracranial, extradural arachnoid cyst in a 5-yearold girl. The child presented with a 2-week history of suspected seizure-like activity and imaging revealed a large midline extradural CSF-containing arachnoid cyst causing severe compression of the superior sagittal sinus and underlying brain. Venous flow through the sagittal sinus was nearly obliterated. Osseous changes and bone growth adjacent to the cyst was also noted on imaging and intraoperatively. She underwent a bifrontal craniotomy and cyst excision with decompression of underlying brain and reestablishment of venous flow through the sagittal sinus.

Intradural pathology and pathophysiology associated with Chiari I malformation in children and adults with and without syringomyelia

OBJECTIVE The pathophysiology underlying tonsillar herniation and CSF obstruction in Chiari malformation Type I (CM-I) is unclear, and the cause of CM-I-associated syringomyelia is not well understood. A better understanding of this pathophysiology is important for an improved treatment strategy. Therefore, the authors sought to identify, characterize, and examine the intradural pathology and CSF flow pathophysiology in the posterior fossa and at the level of the foramen magnum that occurs in the setting of CM-I. They determined the incidence of these intradural findings and assessed differences across age, with the degree of tonsillar herniation, and in the presence and absence of syringomyelia. METHODS A prospective database initiated in March 2003 recorded all intraoperative findings during surgical treatment of children and adults with CM-I with or without syringomyelia. A total of 389 surgeries for CM-I were performed in 379 patients between March 2003 and June 2016. A total of 109 surgeries were performed in 109 patients with CM-I (without osseoligamentous abnormalities) in whom both a posterior fossa extradural and intradural decompression with duraplasty was performed (first-time intradural procedures). Using a surgical microscope, intradural pathology and obstruction of CSF channels were identified and assessed. Student t-tests and Fisher's exact tests compared groups in a series of univariate analyses, followed by multivariate logistic regression. RESULTS The following intradural pathological entities were observed (prevalence noted in parentheses). These include those that did not obstruct CSF flow channels: opacified arachnoid (33.0%), thickened arachnoid (3.7%), ischemic and gliotic tonsils (40.4%), tonsillar cysts (0.9%), and inferior descent of the fourth ventricle and cervicomedullary junction (CMJ) (78.0%). The following intradural pathological entities were observed to obstruct CSF flow channels: medialized tonsils (100%), tonsil overlying and obstructing the foramen of Magendie (21.1%), intertonsillar and tonsil to CMJ arachnoid adhesions (85.3%), vermian posterior inferior cerebellar artery branches obstructing the foramen of Magendie (43.1%), and arachnoid veils or webs obstructing or occluding the foramen of Magendie (52.3%). Arachnoid veils varied in type and were observed in 59.5% of patients with CM-I who had syringomyelia, which was significantly greater than the 33.3% of patients with CM-I without syringomyelia who had an arachnoid veil (p = 0.018). The presence of CM-I with an arachnoid veil had 3.22 times the odds (p = 0.013, 95% CI 1.29-8.07, by multivariate logistic regression) of being associated with syringomyelia, adjusting for tonsillar herniation. The inferior descent of the fourth ventricle and CMJ occurred with a greater degree of tonsillar herniation (p < 0.001) and correlated with a cervicomedullary kink or buckle on preoperative MRI. CONCLUSIONS Intradural pathology associated with CM-I with or without syringomyelia exists in many forms, is more prevalent than previously recognized in patients of all ages, and may play a role in the pathophysiology of CM-I tonsillar herniation. Arachnoid veils appear to partially obstruct CSF flow, are significantly more prevalent in cases of CM-I with syringomyelia, and therefore may play a role in the pathophysiology of CM-I-associated syringomyelia.

Symptomatic spinal extradural arachnoid cyst with cord compression in a family: case report

A family with familial spinal extradural arachnoid cyst is presented. A 14-year-old boy had an extensive T-8 through L-2 dorsal extradural arachnoid cyst with spinal cord compression and slowly progressive myelopathy. His mother had presented 4 years earlier with acute excruciating back pain due to the combination of a lumbar extradural arachnoid cyst at L2–4 and an extruded disc at L3–4. The literature is reviewed in light of the pathogenesis, imaging, and surgical technique required for treatment.

Pediatric meningiomas: 65-year experience at a single institution

OBJECTIVE Meningiomas are relatively common, typically benign neoplasms in adults; however, they are relatively rare in the pediatric population. Pediatric meningiomas behave very differently from their adult counterparts, tending to have more malignant histological subtypes and recur more frequently. The authors of this paper investigate the risk factors, pathological subtypes, and recurrence rates of pediatric meningiomas. METHODS A retrospective chart review was conducted at the University of Iowa to identify patients 20 years old and younger with meningiomas in the period from 1948 to 2015. RESULTS Sixty-seven meningiomas in 39 patients were identified. Eight patients had neurofibromatosis, 2 had a family history of meningioma, and 3 had prior radiation exposure. Twelve (31%) of the 39 patients had WHO Grade II or III lesions, and 15 (38%) had recurrent lesions after resection. CONCLUSIONS Pediatric meningiomas should be considered for early treatment and diligent follow-up.

Reduction of atlantoaxial dislocation prevented by pathological position of the transverse ligament in fixed, irreducible os odontoideum: operative illustrations and radiographic correlates in 41 patients

OBJECTIVE Os odontoideum (OO) is a craniovertebral junction (CVJ) abnormality in which an ossicle (small bone) is cranial to a hypoplastic dens by a variable gap. This abnormality can result in instability, which may be reducible or irreducible. What leads to irreducibility in OO is unclear. Therefore, the authors sought to better understand the causes of irreducibility in OO. METHODS A retrospective review was conducted, which identified more than 200 patients who had undergone surgical treatment for OO between 1978 and 2015 at the University of Iowa Hospitals and Clinics. Only the 41 patients who had irreducible OO were included in this study. All inpatient and outpatient records were retrospectively reviewed, and patient demographics, clinical presentation, radiographic findings, surgical treatment, and operative findings were recorded and analyzed. RESULTS The cohort of 41 patients who were found to have irreducible OO included both children and adults. A majority of patients were adults (61% were 18 years or older). Clinical presentation included neck pain and headache in the majority of patients (93%). Weakness, sensory disturbances, and myelopathy were invariably present in all 41 patients (100%). Down syndrome was much more common in the pediatric cohort than in the adult cohort; of the 16 pediatric patients, 6 had Down syndrome (38%), and none of the adults did. Of the 16 pediatric patients, 5 had segmentation failure (31%) in the subaxial spine, and none of the adults did. A form of atlantoaxial dislocation was seen in all cases. On CT imaging, atlantoaxial facets were dislocated in all 41 cases but did not have osseous changes that would have prevented reduction. On MRI, the transverse ligament was identified anterior and inferior to the ossicle and superior to the hypoplastic odontoid process in all cases in which these studies were available (i.e., post-MRI era; 36 of 36 cases). The ligament was hypointense on T2-weighted images but also had an associated hyperintense signal on T2 images. Intraoperatively, the transverse ligament was identified anterior and inferior to the ossicle and superior to the hypoplastic odontoid process in all 41 cases. CONCLUSIONS In the largest series to date of irreducible OO and the only study to examine variable factors that lead to irreducibility in OO, the authors found that the position of the transverse ligament anterior and inferior to the ossicle is the most common factor in the irreducibility of OO. The presence of granulation tissue and of the dystopic variant of OO is also associated with irreducibility. The presence of Down syndrome and segmentation failure probably leads to faster progression of ligamentous incompetence and therefore earlier presentation of instability and irreducibility. This is the first study in which intraoperative findings regarding the transverse ligament have been correlated with MRI.

Role of resection and adjuvant therapy in long-term disease outcomes for low-grade pediatric intramedullary spinal cord tumors

OBJECTIVE Surgical excision is the mainstay treatment for resectable low-grade intramedullary spinal cord tumors (IMSCTs) in the pediatric age group. Chemotherapy and radiation treatments are generally reserved for progressive or recurrent disease. Given the indolent nature of low-grade tumors and the potential side effects of these approaches, their long-term treatment benefits are unclear. The aim of the study was to determine long-term disease outcomes and the therapeutic roles of surgery and adjuvant therapies in pediatric patients with low-grade IMSCTs over an extended follow-up period. METHODS Case records for all pediatric patients (< 21 years of age) with a histopathological diagnosis of low-grade IMSCT were selected over a period from January 1975 to January 2010. Outcome variables including McCormick functional grade, overall survival (OS), and progression-free survival (PFS) were analyzed with respect to demographic and treatment variables. RESULTS Case records of 37 patients with low-grade IMSCTs were identified, with a mean follow-up duration of 12.3 ± 1.4 years (range 0.5-37.2 years). Low-grade astrocytomas were the most prevalent histological subtype (n = 22, 59%). Gross-total resection (GTR) was achieved in 38% of patients (n = 14). Fusion surgery was required in 62% of patients with pre- or postoperative deformity (10 of 16). On presentation, functional improvement was observed in 87% and 46% of patients in McCormick Grades I and II, respectively, and in 100%, 100%, and 75% in Grades III, IV, and V, respectively. Kaplan-Meier PFS rates were 63% at 5 years, 57% at 10 years, and 44% at 20 years. OS rates were 92% at 5 years, 80% at 10 years, and 65% at 20 years. On multivariate analysis, shunt placement (hazard ratio [HR] 0.33, p = 0.01) correlated with disease progression. There was a trend toward improved 5-year PFS in patients who received adjuvant chemotherapy and radiation therapy (RT; 55%) compared with those who did not (36%). Patients who underwent subtotal resection (STR) were most likely to undergo adjuvant therapy (HR 7.86, p = 0.02). CONCLUSIONS This extended follow-up duration in patients with low-grade IMSCTs beyond the first decade indicates favorable long-term OS up to 65% at 20 years. GTR improved PFS and was well tolerated with sustained functional improvement in the majority of patients. Adjuvant chemotherapy and RT improved PFS in patients who underwent STR. These results emphasize the role of resection as the primary treatment approach, with adjuvant therapy reserved for patients at risk for disease progression and those with residual tumor burden.

Comparison of hinged and contoured rods for occipitocervical arthrodesis in adults: A clinical study

INTRODUCTION

A rigid construct that employs an occipital plate and upper cervical screws and rods is the current standard treatment for craniovertebral junction (CVJ) instability. A rod is contoured to accommodate the occipitocervical angle. Fatigue failure has been associated these acute bends. Hinged rod systems have been developed to obviate intraoperative rod contouring.

OBJECT

The aim of this study is to determine the safety and efficacy of the hinged rod system in occipitocervical fusion.

MATERIALS AND METHODS

This study retrospectively evaluated 39 patients who underwent occipitocervical arthrodesis. Twenty patients were treated with hinged rods versus 19 with contoured rods. Clinical and radiographic data were compared and analyzed.

RESULTS

Preoperative and postoperative Nurick and Frankel scores were similar between both groups. The use of allograft, autograft or bone morphogenetic protein was similar in both groups. The average number of levels fused was 4.1 (±2.4) and 3.4 (±2) for hinged and contoured rods, respectively. The operative time, estimated blood loss, and length of stay were similar between both groups. The occiput to C2 angle was similarly maintained in both groups and all patients demonstrated no movement across the CVJ on flexion-extension X-rays during their last follow-up. The average follow-up for the hinged and contoured rod groups was 12.2 months and 15.9 months, respectively.

CONCLUSION

Hinged rods provide a safe and effective alternative to contoured rods during occipitocervical arthrodesis.

The Application of the Revised Condyle-C1 Interval Method to Diagnose Traumatic Atlanto-occipital Dissociation in Adults

STUDY DESIGN

Retrospective study.

OBJECTIVE

Traumatic atlanto-occipital dissociation (AOD) remains a diagnostic challenge, and delay in diagnosis is associated with catastrophic outcomes. Recently, a revised version of the condyl-C1 interval (CCI) utilizing parasagittal computed tomography (CT) reconstruction was used successfully with unilateral dislocation of 2.5 mm at the level of that joint diagnostic of AOD. We report the utility of this simple technique in the diagnosis of six patients with AOD.

METHODS

Two blinded neurosurgeons assessed CTs of six patients with AOD and 30 patients without AOD. The following methodologies were applied: basion-dens interval (BDI), basion-axial interval (BAI), Lee X-lines, Powers ratio, CCI, and revised CCI. The average sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) as well as the kappa statistic indicating interrater reliability of each method were investigated.

RESULTS

The average sensitivity for BDI, BAI, Lee X-lines, Power ratio, CCI, and revised CCI was 0.75, 0.33, 0.67, 0.50, 1.00, and 1.00, respectively. The average specificity was 1.00, 1.00, 0.50, 1.00, 0.94, and 1.00, respectively. The average PPV was 1.00, 1.00, 0.25, 1.00, 0.80, and 1.00, respectively. The average NPV was 0.96, 0.88, 0.89, 0.91, 1.00, and 1.00, respectively, and the kappa statistic was 0.57, 0.25, 0.25, 0.20, 1.00, and 1.00, respectively.

CONCLUSION

Based on this study, the revised CCI method is simple yet the most sensitive and reliable technique for the diagnosis of AOD.

Evolution of transoral approaches, endoscopic endonasal approaches, and reduction strategies for treatment of craniovertebral junction pathology: a treatment algorithm update

The craniovertebral junction (CVJ), or the craniocervical junction (CCJ) as it is otherwise known, houses the crossroads of the CNS and is composed of the occipital bone that surrounds the foramen magnum, the atlas vertebrae, the axis vertebrae, and their associated ligaments and musculature. The musculoskeletal organization of the CVJ is unique and complex, resulting in a wide range of congenital, developmental, and acquired pathology. The refinements of the transoral approach to the CVJ by the senior author (A.H.M.) in the late 1970s revolutionized the treatment of CVJ pathology. At the same time, a physiological approach to CVJ management was adopted at the University of Iowa Hospitals and Clinics in 1977 based on the stability and motion dynamics of the CVJ and the site of encroachment, incorporating the transoral approach for irreducible ventral CVJ pathology. Since then, approaches and techniques to treat ventral CVJ lesions have evolved. In the last 40 years at University of Iowa Hospitals and Clinics, multiple approaches to the CVJ have evolved and a better understanding of CVJ pathology has been established. In addition, new reduction strategies that have diminished the need to perform ventral decompressive approaches have been developed and implemented. In this era of surgical subspecialization, to properly treat complex CVJ pathology, the CVJ specialist must be trained in skull base transoral and endoscopic endonasal approaches, pediatric and adult CVJ spine surgery, and must understand and be able to treat the complex CSF dynamics present in CVJ pathology to provide the appropriate, optimal, and tailored treatment strategy for each individual patient, both child and adult. This is a comprehensive review of the history and evolution of the transoral approaches, extended transoral approaches, endoscopie assisted transoral approaches, endoscopie endonasal approaches, and CVJ reduction strategies. Incorporating these advancements, the authors update the initial algorithm for the treatment of CVJ abnormalities first published in 1980 by the senior author.

Clinical presentation and management of proatlas segmentation defect presenting with palatal myoclonus: case report

Clinical presentation of craniovertebral junction disorders may range from acute catastrophic neurological deficits to insidious signs and symptoms that may mask the underlying etiology. Prompt recognition and treatment is essential to avert long-term neurological morbidity. Proatlas segmentation disorders are a rare group of developmental disorders involving the craniocervical junction. Abnormal bony segmentation leads to malformed bony structures that can in turn lead to neurological deficits through bony compression of the cervicomedullary junction. This report details a proatlas segmentation defect presenting as palatal myoclonus, a rare movement disorder. The clinical presentation, surgical management, and neuroanatomical basis for the disorder is presented. This report highlights the myriad clinical presentations of craniovertebral disorders and emphasizes a rare but treatable etiology for palatal myoclonus.

Syringohydromyelia in association with syringobulbia and syringocephaly: case report

The authors present the case of a 14-year-old boy with holocord syringohydromyelia extending into the brainstem, cerebral peduncle, internal capsule, and cerebral cortex. At the posterior fossa exploration, an opaque thickened arachnoid with occlusion of the foramen of Magendie was encountered. Careful documentation of postoperative regression of the syringocephaly, syringobulbia, and syringohydromyelia was made. The pathophysiology is discussed.

Disease outcomes for skull base and spinal chordomas: a single center experience

OBJECTIVE

Chordomas carry significant morbidity due to their growth patterns and surgical constraints in resection. En bloc resection, when feasible, is the ideal treatment goal, but is associated with significant morbidity. We sought to elucidate the relationship between extent of surgery, location and radiotherapy in relation to overall disease and progression free survival (PFS).

METHODS

We reviewed case records for all patients with a primary histopathological diagnosis of clival and spinal chordomas that was presented to our institution between 1978 and 2010.

RESULTS

A total of 49 patients (location: n=30, skull base/clival; n=12 vertebral column; n=7 sacrum) were identified with mean follow-up period of 6.3 years (range 0.25 months-33 years). Improved 5 year and 10 year survival rates were noted following gross total resection (n=8, 5 year and 10 year survival=88%) as compared to patients that underwent subtotal resection (n=41, 55% and 31%, respectively), (p-value>0.05, GTR versus STR). Adjuvant high-dose stereotactic fractionated radiotherapy (HS-FSRT) significantly improved 5 year PFS in craniocervical chordoma patients (70%, n=13) as compared to standard dose radiation therapy (20%, n=16; p-value=0.03). Overall 10 year survival for craniocervical patients undergoing HD-FSRT (40%) was however not significantly different in comparison with conventional radiotherapy (45%). Sacral chordomas had the worst prognosis with 3 year survival of 28.6%.

CONCLUSIONS

GTR offers the best prognosis for improved long-term survival. Adjuvant HD FSRT for cranio-cervical/clival chordomas significantly improves disease free survival though the long-term benefits on survival have yet to be established. Sacral chordomas are associated with a worse prognosis and poor long-term survival.

Intradiploic occipital pseudomeningocele in a patient with remote history of surgical treatment of Chiari malformation

An intradiploic CSF pseudocyst is a rare entity that has been described in association with trauma, as a sequela of untreated hydrocephalus, or occasionally as a congenital finding in older adults. The authors present the case of a woman with a remote history of a posterior fossa intradural procedure, in which she underwent Chiari malformation decompression, Silastic substitute–assisted duraplasty, and occipitocervical fusion; she presented 19 years later with recurrent symptoms of Chiari malformation. She was found to have an occipital intradiploic pseudomeningocele, arising within her dorsal occipitocervical fusion mass and resulting in dorsal hindbrain compression. She underwent a posterior fossa decompression and revision of her failed duraplasty, and she had a good recovery. This case demonstrates intradiploic CSF pseudomeningocele as a rare potential delayed complication of an intradural procedure for the treatment of Chiari malformation with occipitocervical fusion.

Long-term incidence and risk factors for development of spinal deformity following resection of pediatric intramedullary spinal cord tumors

OBJECT

Spinal deformity in pediatric patients with intramedullary spinal cord tumors (IMSCTs) may be either due to neurogenic disability or due to secondary effects of spinal decompression. It is associated with functional decline and impairment in health-related quality-of-life measures. The authors sought to identify the long-term incidence of spinal deformity in individuals who had undergone surgery for IMSCTs as pediatric patients and the risk factors and overall outcomes in this population.

METHODS

Treatment records for pediatric patients (age < 21 years) who underwent surgical treatment for histology-proven primary IMSCTs between 1975 and 2010 were reviewed. All patients were evaluated in consultation with the pediatric orthopedics service. Clinical records were reviewed for baseline and follow-up imaging studies, surgical fusion treatment, and long-term skeletal and disease outcomes.

RESULTS

The authors identified 55 patients (30 males and 25 females) who were treated for pediatric IMSCTs between January 1975 and January 2010. The mean duration of follow-up (± SEM) was 11.4 ± 1.3 years (median 9.3 years, range 0.2-37.2 years). Preoperative skeletal deformity was diagnosed in 11 (20%) of the 55 patients, and new-onset postoperative deformity was noted in 9 (16%). Conservative management with observation or external bracing was sufficient in 8 (40%) of these 20 cases. Surgical fusion was necessary in 11 (55%). Posterior surgical fusion was sufficient in 6 (55%) of these 11 cases, while combined anterior and posterior fusion was undertaken in 5 (45%). Univariate and multivariate analysis of clinical and surgical treatment variables indicated that preoperative kyphoscoliosis (p = 0.0032) and laminectomy/laminoplasty at more than 4 levels (p = 0.05) were independently associated with development of spinal deformity that necessitated surgical fusion. Functional scores and 10-year disease survival outcomes were similar between the 2 groups.

CONCLUSIONS

Long-term follow-up is essential to monitor for delayed development of spinal deformity, and regular surveillance imaging is recommended for patients with underlying deformity. The authors' extended follow-up highlights the risk factors associated with development of spinal deformity in patients treated for pediatric IMSCTs. Surgical fusion allows patients who develop progressive deformity to achieve long-term functional and survival outcomes comparable to those of patients who do not develop progressive deformity.

Long-term disease and neurological outcomes in patients with pediatric intramedullary spinal cord tumors

OBJECT

Radical resection is recommended as the first-line treatment for pediatric intramedullary spinal cord tumors (IMSCTs), but it is associated with morbidity, including risk of neurological decline and development of postoperative spinal deformity. The authors report long-term data on clinical and treatment determinants affecting disease survival and neurological outcomes.

METHODS

Case records for pediatric patients (< 21 years of age at presentation) who underwent surgery for IMSCTs at the authors' institution between January 1975 and January 2010 were analyzed. The patients' demographic and clinical characteristics (including baseline neurological condition), the treatment they received, and their disease course were reviewed. Long-term disease survival and functional outcome measures were analyzed.

RESULTS

A total of 55 patients (30 male and 25 female) were identified. The mean duration of follow-up (± SEM) was 11.4 ± 1.3 years (median 9.3 years, range 0.2-37.2 years). Astrocytomas were the most common tumor subtype (29 tumors [53%]). Gross-total resection (GTR) was achieved in 21 (38%) of the 55 patients. At the most recent follow-up, 30 patients (55%) showed neurological improvement, 17 (31%) showed neurological decline, and 8 (15%) remained neurologically stable. Patients presenting with McCormick Grade I were more likely to show functional improvement by final follow-up (p = 0.01) than patients who presented with Grades II-V. Kaplan-Meier actuarial tumor progression-free survival rates at 5, 10, and 20 years were 61%, 54%, and 44%, respectively; the overall survival rates were 85% at 5 years, 74% at 10 years, and 64% at 20 years. On multivariate analysis, GTR (p = 0.04) and tumor histological grade (p = 0.02) were predictive of long-term survival; GTR was also associated with improved 5-year progression-free survival (p = 0.01).

CONCLUSIONS

The prognosis for pediatric IMSCTs is favorable with sustained functional improvement expected in a significant proportion of patients on long-term follow-up. Long-term survival at 10 years (75%) and 20 years (64%) is associated with aggressive resection. Gross-total resection was also associated with improved 5-year progression-free survival (86%). Hence, the treatment benefits of GTR are sustained on extended follow-up.

Primary atlantoaxial bone tumors in children: management strategies and long-term follow-up

OBJECT

Atlantoaxial tumors account for a substantial proportion of primary bone tumors in children. Before resection, surgeons must consider the complex regional anatomy, the potential for neurological compromise, craniocervical instability, and the question of tumor resectability in a growing spine. Using current technology, the authors analyzed surgical cases in this light and present outcomes and treatment recommendations after long-term patient follow-up.

METHODS

The authors reviewed clinical records for 23 children whose primary atlantoaxial bone tumors were treated from 1996 through 2010.

RESULTS

Pathological lesions among the 23 patients were 4 aneurysmal bone cysts, 2 osteochondromas, 5 chordomas, 4 osteoblastomas, 3 fibrous dysplasias, 4 eosinophilic granulomas, and 1 Ewing's sarcoma. Clinical presentation consisted of neck pain (n = 23), headaches and occipital pain (n = 16), myelopathy (n = 8), and torticollis (n = 4). Selective angiography and coil embolization were undertaken for all patients with aneurysmal bone cysts and osteoblastomas, 2 patients with chordomas, 1 patient with fibrous dysplasia, and 1 patient with Ewing's sarcoma. Primary embolization treatment of radiation-induced aneurysmal bone cyst of the atlas showed complete reossification. Results of CT-guided needle biopsy were diagnostic for 1 patient with eosinophilic granuloma and 1 with Ewing's sarcoma. Needle biopsies performed before referral were associated with extreme blood loss for 1 patient and misdiagnosis for 2 patients. Surgery involved lateral extrapharyngeal, transoral, posterior, and posterolateral approaches with vertebral artery rerouting. Complete resection was possible for 9 patients (2 with osteochondroma, 3 with fibrous dysplasia, 2 with chordoma, and 2 with osteoblastoma). Decompression and internal fusion were performed for 3 patients with aneurysmal bone cysts. Of the 23 patients, 7 underwent dorsal fusion and 4 underwent ventral fusion of the axis body. Chemotherapy was necessary for the patients with eosinophilic granuloma with multifocal disease and for the patient with Ewing's sarcoma. There was no morbidity, and there were no deaths. All patients with benign lesions were free of disease at the time of the follow-up visit (mean ± SD follow-up 8.8 ± 1.1 years; range 2-18 years). Chordomas received proton or LINAC irradiation, and as of 4-15 years of follow-up, no recurrence has been noted.

CONCLUSIONS

Because most atlantoaxial tumors in children are benign, an intralesional procedure could suffice. Vascular control and staged resection are critical. Ventral transoral fusion or lateral extrapharyngeal fusion has been successful. Resection with ventral fusion and reconstruction are essential for vertebral body collapse. Management of eosinophilic granulomas must be individualized and might require diagnosis through needle biopsy.

Management of operative complications related to occipitocervical instrumentation

BACKGROUND

The continued evolution of instrumentation techniques for fusions at the craniovertebral junction has enabled surgical treatment of a wide range of developmental, neoplastic, traumatic, and degenerative conditions. There has been an increased recognition of the morbidity associated with the complications secondary to occipitocervical instrumentation.

OBJECTIVE

To present representative complications secondary to occipitocervical instrumentation in patients who presented to our institution and to emphasize underlying principles in diagnosis and management of craniovertebral disease conditions through illustrative examples of their presentation, management, and follow-up.

METHODS

Clinical records for patients referred to the senior author (A.H.M.) between 2005 and 2010 for evaluation and management of their symptoms arising as a consequence of surgical intervention by a different primary neurosurgeon were reviewed.

RESULTS

Eight patients were identified with representative complications secondary to occipitocervical instrumentation. These complications included incorrect surgical technique, persistent instability, hardware misplacement with potential for vascular injury, associated neural injury, and secondary complications of wound healing resulting from methyl methacrylate use. Surgical revision was required in 2 patients. The remaining patients improved with removal of the offending hardware and acrylic cement. All patients reported symptom resolution, and dynamic imaging studies on follow-up indicated stable alignment and bony fusion.

CONCLUSION

These cases serve as illustrative examples of the spectrum of neural, vascular, biomechanical, and instrument-related complications associated with occipitocervical arthrodesis. Basic principles of occipitocervical instrumentation that enable safe and successful treatment of craniovertebral junction disease conditions have been highlighted. Potential complications and management strategies are discussed.