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 C2-6anterior 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.

Integrity of the tectorial membrane is a favorable prognostic factor in atlanto-occipital dislocation.

Objective: Atlanto-occipital dislocation is usually considered to be a fatal injury or one that leaves the victim with serious neurological deficits. The aim of this study is to illustrate a novel positive prognostic factor for atlanto-occipital dislocation, based on cervical MRI studies of patients who suffered this injury.Methods: Over the course of the past year, the authors have treated three consecutive patients with atlanto-occipital dislocation who attained an excellent clinical outcome. We retrospectively evaluated clinical, surgical and radiographic parameters in search of a common denominator to explain the excellent outcome of these patients.Results: All patients presented with severe polytrauma that required urgent surgical intervention including two laparotomies and a thoracotomy. The patients were subsequently treated with an occipitocervical fusion. No patient developed neurological deficits on long-term follow-up. The cervical MRI studies of all patients were notable for a having a preserved tectorial membrane, while other primary stabilizers of the craniocervical junction such as the apical, alar and cruciate ligaments were shown to be severely disrupted. We consider this anatomical distinction to account for their benign clinical course.Conclusion: A preserved tectorial membrane appears to be an important favorable prognostic factor in atlanto-occipital dislocation and may serve to mitigate neurological outcome in such injuries. To determine the integrity of the ligament and consequently affect clinical management, expeditious MRI of the cranio-cervical junction should be considered routinely in such injuries in addition to cervical CT scans.

Surgical considerations in posterior C1-2 instrumentation in the presence of vertebral artery anomalies: case illustration and review of literature.

Vascular anomalies involving the V3 segment of the vertebral artery are common and may complicate posterior atlantoaxial instrumentation. We report a patient with a fenestrated vertebral artery that underwent successful C1-2 instrumentation and fusion. Various vertebral artery anomalies are discussed with a review of pertinent literature.

Cervical arthroplasty: what does the labeling say?

OBJECTIVE The aim of this paper was to comprehensively review each of the Food and Drug Administration (FDA)-approved labels of 7 total cervical disc replacements, assess the exact methodology in which the trial was conducted, and provide a broad comparison of these devices to allow each surgeon to determine which disc best suits his or her specific treatment goals based on the specific labels and not the studies published. METHODS The FDA-approved labels for each of the 7 artificial discs were obtained from the official FDA website. These labels were meticulously compared with regard to the statistical analysis performed, the safety and efficacy data, and the randomized controlled trial that each artificial disc was involved in to obtain the FDA approval for the product or device. Both single-level and 2-level approvals were examined, and primary and secondary end points were assessed. RESULTS In the single-level group, 4 of the 7 artificial discs-Prestige LP, Prestige ST, Bryan, and Secure-C-showed superiority in overall success. Prestige ST showed superiority in 3 of 4 outcome measures (neurological success, revision surgery, and overall success), while the other aforementioned discs showed superiority in 2 or fewer measures (Prestige LP, neurological and overall success; Bryan, Neck Disability Index [NDI] and overall success; Secure-C, revision surgery and overall success; Pro-Disc C, revision surgery). The PCM and Mobi-C discs demonstrated noninferiority across all outcome measures. In the 2-level group, Prestige LP and Mobi-C demonstrated superiority in 3 outcome measures (NDI, secondary surgery, and overall success) but not neurological success. CONCLUSIONS This paper provides a comprehensive analysis of 7 currently approved and distributed artificial discs in the United States. It compares specific outcome measures of these devices against those following the standard of care, which is anterior cervical discectomy and fusion. This information will provide surgeons the opportunity to easily answer patients' questions and remain knowledgeable when discussing devices with manufacturers.

Intubation Biomechanics: Laryngoscope Force and Cervical Spine Motion during Intubation in Cadavers-Cadavers versus Patients, the Effect of Repeated Intubations, and the Effect of Type II Odontoid Fracture on C1-C2 Motion.

BACKGROUND: The aims of this study are to characterize (1) the cadaver intubation biomechanics, including the effect of repeated intubations, and (2) the relation between intubation force and the motion of an injured cervical segment. METHODS: Fourteen cadavers were serially intubated using force-sensing Macintosh and Airtraq laryngoscopes in random order, with simultaneous cervical spine motion recorded with lateral fluoroscopy. Motion of the C1-C2 segment was measured in the intact and injured state (type II odontoid fracture). Injured C1-C2 motion was proportionately corrected for changes in intubation forces that occurred with repeated intubations. RESULTS: Cadaver intubation biomechanics were comparable with those of patients in all parameters other than C2-C5 extension. In cadavers, intubation force (set 2/set 1 force ratio = 0.61; 95% CI, 0.46 to 0.81; P = 0.002) and Oc-C5 extension (set 2 - set 1 difference = -6.1 degrees; 95% CI, -11.4 to -0.9; P = 0.025) decreased with repeated intubations. In cadavers, C1-C2 extension did not differ (1) between intact and injured states; or (2) in the injured state, between laryngoscopes (with and without force correction). With force correction, in the injured state, C1-C2 subluxation was greater with the Airtraq (mean difference 2.8 mm; 95% CI, 0.7 to 4.9 mm; P = 0.004). CONCLUSIONS: With limitations, cadavers may be clinically relevant models of intubation biomechanics and cervical spine motion. In the setting of a type II odontoid fracture, C1-C2 motion during intubation with either the Macintosh or the Airtraq does not appear to greatly exceed physiologic values or to have a high likelihood of hyperextension or direct cord compression.

Surgical resection of subependymoma of the cervical spinal cord.

Subependymomas can rarely occur in the spinal cord, and account for about 2% of symptomatic spinal cord tumors. It most often occurs in the cervical spinal cord, followed by cervicothoracic junction, thoracic cord and conus medullaris. It often has an eccentric location in the spinal cord and lacks gadolinium enhancement on magnetic resonance imaging. We present a rare case of symptomatic subependymoma of the cervical spinal cord, which underwent successful gross total resection. Surgical pearls and nuances are discussed to help surgeons to avoid potential complications. The video can be found here: http://youtu.be/Rsm9KxZX7Yo.

Correction: The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis).

[This corrects the article DOI: 10.1371/journal.pone.0274634.].

The Evolving Role of Postgraduate Year 7 in Neurological Surgery Residency.

BACKGROUND AND OBJECTIVES: In 2013, all neurosurgery programs were mandated to adopt a 7-year structure. We sought to characterize how programs use the seventh year of training (postgraduate year 7 [PGY7]). METHODS: We surveyed all accredited neurosurgery programs in the United States regarding the PGY7 residents' primary role and the availability of enfolded fellowships. We compiled responses from different individuals in each program: chair, program director, program coordinator, and current chiefs. RESULTS: Of 120 accredited neurological surgery residency programs within the United States, 91 (76%) submitted responses. At these programs, the primary roles of the PGY7 were chief of service (COS, 71%), enfolded fellowships (EFF, 18%), transition to practice (10%), and elective time (1%). Most residencies have been 7-year programs for >10 years (52, 57%). Sixty-seven programs stated that they offer some form of EFF (73.6%). The most common EFFs were endovascular (57, 62.6%), spine (49, 53.9%), critical care (41, 45.1%), and functional (37, 40.7%). These were also the most common specialties listed as Committee on Advanced Subspecialty Training accredited by survey respondents. Spine and endovascular EFFs were most likely to be restricted to PGY7 (24.2% and 23.1%, respectively), followed by neuro-oncology (12, 13.2%). The most common EFFs reported as Committee on Advanced Subspecialty Training accredited but not restricted to PGY7 were endovascular (24, 26.4%) and critical care (23, 25.3%). CONCLUSION: Most accredited neurological surgery training programs use the COS as the primary PGY7 role. Programs younger in their PGY7 structure seem to maintain the traditional COS role. Those more established seem to be experimenting with various roles the PGY7 year can fill, including enfolded fellowships and transition-to-practice years, predominantly. Most programs offer some form of enfolded fellowship. This serves as a basis for characterization of how neurological surgery training may develop in years to come.

Risk factors for C5 palsy: a systematic review and multivariate analysis.

OBJECTIVE: Postoperative C5 palsy (C5P) is a known complication in cervical spine surgery. However, its exact pathophysiology is unclear. The authors aimed to provide a review of the current understanding of C5P by performing a comprehensive, systematic review of the existing literature and conducting a critical appraisal of existing evidence to determine the risk factors of C5P. METHODS: A systematic search of PubMed/MEDLINE (January 1, 2019, to July 2, 2021), EMBASE (inception to July 2, 2021), and Cochrane (inception to July 2, 2021) databases was conducted. Preestablished criteria were used to evaluate studies for inclusion. Studies that adjusted for one or more of the following factors were considered: preoperative foraminal diameter (FD) at C4/5, posterior spinal cord shift at C4/5, preoperative anterior-posterior diameter (APD) at C4/5, preoperative spinal cord rotation, and change in C2-7 Cobb angle. Studies were rated as good, fair, or poor based on the Quality in Prognosis Studies (QUIPS) tool. Random effects meta-analyses were done using methods outlined by Cochrane methodologists for pooling of prognostic studies. Overall quality (strength) of evidence was based on Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methods for prognostic studies. The protocol for this review was published on the PROSPERO (CRD264358) website. RESULTS: Of 303 potentially relevant citations of studies, 12 met the inclusion criteria set a priori. These works provide moderate-quality evidence that preoperative FD substantially increases the odds of C5P in patients undergoing posterior cervical surgery. Pooled estimates across 7 studies in which various surgical approaches were used indicate that the odds of C5P approximately triple for each millimeter decrease in preoperative FD (OR 3.05, 95% CI 2.07-4.49). Preoperative APD increases the odds of C5P, but the confidence is low. Across 3 studies, each using different surgical approaches, each millimeter decrease in preoperative APD was associated with a more than 2-fold increased odds of C5P (pooled OR 2.51, 95% CI 1.69-3.73). Confidence that there is an association with postoperative C5P and posterior spinal cord shift, change in sagittal Cobb angle, and preoperative spinal cord rotation is very low. CONCLUSIONS: The exact pathophysiological process resulting in postoperative C5P remains an enigma but there is a clear association with foraminal stenosis, especially when performing posterior procedures. C5P is also related to decreased APD but the association is less clear. The overall quality (strength) of evidence provided by the current literature is low to very low for most factors. Systematic review registration no.: CRD264358 (https://www.crd.york.ac.uk/prospero/).

Failure of porous tantalum cervical interbody fusion devices: two-year results from a prospective, randomized, multicenter clinical study.

OBJECTIVE: The objective of this study was to assess the safety and efficacy of 2 novel cervical interbody fusion devices in the treatment of single-level degenerative cervical disk disease. Both devices were fabricated from a porous tantalum material. The high overall porosity of the devices was intended to facilitate anterior cervical interbody fusion. METHODS: A prospective, randomized, 3-armed, clinical study was initiated with the following treatment groups: porous tantalum ring device packed with autograft, porous tantalum block device, and iliac crest autograft control. All the patients had single-level symptomatic cervical disk disease that had failed to respond to nonoperative therapy. Clinical and radiographic data were collected preoperatively, during surgery, before hospital discharge, and at 6 weeks, 3 months, 6 months, 12 months, and 24 months postoperatively. RESULTS: Six investigators participated in the clinical study at 6 investigational centers in the United States. Enrollment into the study was terminated after 39 patients had been accrued because of concerns over delayed fusion in the porous tantalum treatment groups. Of the 39 patients enrolled into the clinical study, 11 patients received the control treatment of iliac autograft fusion, 13 patients received the porous tantalum ring device with the center cavity packed with cancellous iliac crest autograft, and 15 patients received the porous tantalum block device. These patients were evaluated for 24 months as per the study protocol. There were no significant differences in any of the patient demographic variables collected. The mean operative times for both the ring and block device groups were slightly lower than the control treatment. Two patients in the block treatment group were determined to be nonunion between the 6- and 12-month time points and underwent additional surgery. Five patients with porous tantalum devices showed radiographic evidence of device fragmentation, and one patient in addition had radiographic evidence of erosion of the involved vertebral bodies by the device. One patient in the ring treatment group died from a myocardial infarction and kidney failure subsequent to the 12-month follow-up visit, which was unrelated to the device or the spinal fusion procedure. Fusion rate at 2 years for the tantalum device was very low as compared with the control arm (44% vs. 100%). Patient Neck Disability Index scores, Short Form-36 scores, and neurological status scores were similar between the 3 treatment groups. CONCLUSIONS: This study demonstrates that stand-alone porous tantalum material is not ideal for a cervical spine interbody fusion because of the low rate of arthrodesis and the risk of device fragmentation in patients who fail to fuse.

Comparison of Perioperative Complications After Anterior-Posterior Versus Posterior-Anterior-Posterior Cervical Fusion: A Retrospective Review of 153 Consecutive Cases.

BACKGROUND: Although published data support the utilization of circumferential fusion to treat select cervical spine pathologies, it is unclear whether the posterior-anterior-posterior (PAP) fusion has increased risks compared with the anterior-posterior fusion. OBJECTIVE: To evaluate the differences in perioperative complications between the 2 circumferential cervical fusion approaches. METHODS: One hundred fifty-three consecutive adult patients who underwent single-staged circumferential cervical fusion for degenerative pathologies from 2010 to 2021 were retrospectively reviewed. Patients were stratified into the anterior-posterior ( n = 116) and PAP ( n = 37) groups. The primary outcomes assessed were major complications, reoperation, and readmission. RESULTS: Although the PAP group was older ( P = .024), predominantly female ( P = .024), with higher baseline neck disability index ( P = .026), cervical sagittal vertical axis ( P = .001), and previous cervical operation rate ( P < .00001), the major complication, reoperation, and readmission rates were not significantly different from the 360° group. Although the PAP group had higher urinary tract infection ( P = .043) and transfusion ( P = .007) rates, higher estimated blood loss ( P = .034), and longer operative times ( P < .00001), these differences were insignificant after the multivariable analysis. Overall, operative time was associated with older age (odds ratio [OR] 17.72, P = .042), atrial fibrillation (OR 158.30, P = .045), previous cervical operation (OR 5.05, P = .051), and lower baseline C1 - 7 lordosis (OR 0.93, P = .007). Higher estimated blood loss was associated with older age (OR 1.13, P = .005), male gender (OR 323.31, P = .047), and higher baseline cervical sagittal vertical axis (OR 9.65, P = .022). CONCLUSION: Despite some differences in preoperative and intraoperative variables, this study suggests both circumferential approaches have comparable reoperation, readmission, and complication profiles, all of which are high.

Preservation of spinal instrumentation after development of postoperative bacterial infections in patients undergoing spinal arthrodesis.

STUDY DESIGN: This is a retrospective review. OBJECTIVE: The purpose of this study is to evaluate the efficacy of medical and surgical management of postoperative infections after the placement of spinal instrumentation in the context of retaining the instrumentation. SUMMARY OF BACKGROUND DATA: The implementation of spinal instrumentation for the treatment of various spinal conditions is associated with a risk of developing a postoperative wound infection. An aggressive medical and surgical approach is necessary for eradication of subfascial infections and treatment is often performed with the guidance of infectious diseases consultants. These medical specialists frequently recommend removal of the implanted spinal instrumentation due to the concern for the potential of persistent microbial infection resulting from the formation of bacteria harboring biofilm on the indwelling spinal hardware. METHODS: Of 854 consecutive patients who had undergone spinal instrumentation by the senior author, 17 patients were identified who developed postoperative infections, 16 of which were treated by the senior author. RESULTS: All patients underwent surgical debridement and received antimicrobial therapy in consultation with the infectious diseases consultants. Spinal instrumentation was preserved in all cases. Two patients had clinical and radiologic evidence of nonunion and later underwent a staged instrumentation revision procedure. Eradication of the infection was successful in all patients. The mean follow-up period was 2.1 years (range, 12 mo to 4.5 y). CONCLUSIONS: A combination of aggressive surgical debridement with microbial-guided pharmacotherapy enabled infection cure in all patients with postoperative bacterial infections after spinal instrumentation. Adjunct measures including the use of wound vacuum devices and long-term suppressive antimicrobial therapy were also used in high-risk patients. These results show that postoperative bacterial infections in the setting of spinal instrumentation can be successfully treated without removing titanium alloy instrumentation.

The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis).

BACKGROUND & IMPORTANCE: This patient and public-involved systematic review originally focused on arachnoiditis, a supposedly rare "iatrogenic chronic meningitis" causing permanent neurologic damage and intractable pain. We sought to prove disease existence, causation, symptoms, and inform future directions. After 63 terms for the same pathology were found, the study was renamed Diseases of the Leptomeninges (DLMs). We present results that nullify traditional clinical thinking about DLMs, answer study questions, and create a unified path forward. METHODS: The prospective PRISMA protocol is published at Arcsology.org. We used four platforms, 10 sources, extraction software, and critical review with ≥2 researchers at each phase. All human sources to 12/6/2020 were eligible for qualitative synthesis utilizing R. Weekly updates since cutoff strengthen conclusions. RESULTS: Included were 887/14286 sources containing 12721 DLMs patients. Pathology involves the subarachnoid space (SAS) and pia. DLMs occurred in all countries as a contributor to the top 10 causes of disability-adjusted life years lost, with communicable diseases (CDs) predominating. In the USA, the ratio of CDs to iatrogenic causes is 2.4:1, contradicting arachnoiditis literature. Spinal fusion surgery comprised 54.7% of the iatrogenic category, with rhBMP-2 resulting in 2.4x more DLMs than no use (p<0.0001). Spinal injections and neuraxial anesthesia procedures cause 1.1%, and 0.2% permanent DLMs, respectively. Syringomyelia, hydrocephalus, and arachnoid cysts are complications caused by blocked CSF flow. CNS neuron death occurs due to insufficient arterial supply from compromised vasculature and nerves traversing the SAS. Contrast MRI is currently the diagnostic test of choice. Lack of radiologist recognition is problematic. DISCUSSION & CONCLUSION: DLMs are common. The LM clinically functions as an organ with critical CNS-sustaining roles involving the SAS-pia structure, enclosed cells, lymphatics, and biologic pathways. Cases involve all specialties. Causes are numerous, symptoms predictable, and outcomes dependent on time to treatment and extent of residual SAS damage. An international disease classification and possible treatment trials are proposed.

Minimally Invasive Posterior Cervical Foraminotomy Versus Anterior Cervical Fusion and Arthroplasty: Systematic Review and Meta-Analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVES: Patients with lateral cervical disc and foraminal pathology can be treated with anterior and posterior approaches including anterior cervical discectomy and fusion(ACDF), cervical total disc arthroplasty(TDA), and minimally invasive posterior cervical foraminotomy(MIS-PCF). Although MIS-PCF may have some advantages over the anterior approaches, few comparative studies and meta-analyses have been done to assess superiority. METHODS: This study includes a systematic review of the literature and meta-analysis of studies directly comparing minimally invasive posterior cervical foraminotomy to either anterior cervical discectomy and fusion or cervical total disc arthroplasty. RESULTS: In comparing patients undergoing ACDF and MIS-PCF, operative time ranged from 68 to 97.8 minutes in the ACDF group compared to 28 to 93.9 minutes in the MIS-PCF group. Mean postoperative length of stay ranged from 33.84 to 112.8 hours in the ACDF group compared to 13.68 to 83.6 hours in the MIS-PCF group. The total complication rates were 3.72% in the ACDF group and 3.73% in the MIS-PCF group. A random-effects model meta-analysis was carried out which failed to show a statistically significant difference in the complication rate between the two procedures(OR .91; 95% CI 0.13, 6.43; P = .92, I2 = 59%). The total reoperation rate was 3.5% in the ACDF group and 5.4% in the MIS-PCF group. A random-effects model meta-analysis was carried out which failed to show a statistically significant difference in the reoperation rate between the two procedures(OR .66; 95% CI 0.33, 1.33; P = .25, I2 = 0). In comparing patients undergoing TDA and MIS-PCF, operative time ranged from 90.3 to 106.7 minutes in the TDA group compared to 77.4 to 93.9 minutes in the MIS-PCF group. Mean postoperative length of stay ranged from 103.2 to 165.6 hours in the TDA group and 93.6 to 98.4 hours in the MIS-PCF group. The complication rate ranged from 23.5 to 28.6% in the TDA group and 0 to 14.3% in the MIS-PCF group. The overall reoperation rates were 2.6% in the TDA group and 10.2% in the MIS-PCF group. CONCLUSIONS: There is no clear superiority between MIS-PCF and ACDF/TDA in terms of operative time, postoperative length of stay, or rate of complications/reoperations. Further studies with increased follow-up intervals >48 months, and higher sample sizes are necessary to determine the true superiority of MIS-PCF and anterior neck approaches in treatment of lateral disc and foraminal pathology.

Clinical Outcomes After 4- and 5-Level Anterior Cervical Discectomy and Fusion for Treatment of Symptomatic Multilevel Cervical Spondylosis.

OBJECTIVE: There are limited patient-reported outcome measure (PROM) data on 4-level and 5-level anterior cervical discectomy and fusion (ACDF). The largest series to date solely focused on complications. This retrospective series evaluates PROMs after 4-level and 5-level ACDF. METHODS: Pertinent data from adult patients treated with a 4-level or 5-level ACDF in 2011-2019 were analyzed. PROMs and minimal clinically important differences (MCIDs) were assessed. Factors associated with favorable and unfavorable outcomes were identified. RESULTS: There were 34 patients (30 underwent 4-level and 4 underwent 5-level ACDFs) with a mean age of 59.6 years; 55.9% were women. At 3 months, there were significant improvements in PROMs except Short-Form 12-Item Survey (SF-12) mental component subscale, which showed modest improvement. At 12 months, there were significant improvements in PROMs except SF-12 physical component subscale (PCS), which showed moderate improvement. The proportions of patients who met the MCID cutoffs ranged from 35.3% (numeric rating scale [NRS]-neck) to 75% (Veteran RAND 12-Item Survey [VR-12] PCS) at 3 months and 38.2% (NRS-arm) to 65.5% (VR-12 mental component subscale) at 12 months. Shorter symptom duration was associated with significantly reduced postoperative pain and Neck Disability Index scores. Shorter length of stay was associated with significantly improved postoperative functional outcomes. patients undergoing 4-level compared with 5-level ACDF achieved better postoperative PROMs. Shorter procedure duration was associated with improved PROMs at 3 months. No patient returned to the operating room within 30 days. Patients who required reoperation achieved significantly inferior Neck Disability Index, NRS-neck, and SF-12 PCS scores at 3 months. CONCLUSIONS: This study showed satisfactory PROMs up to 12 months after 4-level and 5-level ACDF despite the complication rate. With thorough preoperative planning and meticulous technique, performing this procedure in carefully selected patients may be associated with acceptable PROMs.

Comparison of Fusion versus Nonunion After 4-Level and 5-Level Anterior Cervical Diskectomy and Fusion With Anterior Plate Fixation.

BACKGROUND: Nonunion remains a concern in multilevel anterior cervical discectomy and fusion (ACDF), yet there are limited data on nonunion after 4 to 5-level ACDF. In fact, the largest series on 4-level or 5-level ACDF focused specifically on the swallowing outcomes. OBJECTIVE: To assess nonunion after 4 to 5-level ACDF. METHODS: Forty-one patients treated with 4 to 5-level ACDF with minimum of 12-month radiographic follow-up were retrospectively reviewed. Nonunion was found in 25 patients (61%) and 42 levels (25%) and complete fusion in 16 (39%) patients and 126 levels (75%). The 2 groups were further compared. RESULTS: One-level nonunion was by far the most common pattern compared with multilevel nonunion. Nonunion occurred more frequently at the caudal than the cranial or middle segments ( P < .0001). There were significantly more subsidence ( P < .0001) and screw fractures/pullouts ( P < .0001) in the nonunion compared with the fusion group. The symptomatic patients were significantly younger than the asymptomatic patients ( P = .044). The symptomatic levels were significantly more than asymptomatic levels ( P = .048). Equal proportion of patients implanted with allograft and polyetheretherketone had nonunion. However, there were markedly more nonunion than fused levels with allograft and more fused than nonunion levels with polyetheretherketone ( P = .023). The reoperation rate was 24.4% and mostly due to nonunion. There were no reoperations within 90 days of the primary surgery. CONCLUSION: The nonunion rate for 4-level and 5-level ACDF may be higher than previously reported. Symptomatic nonunion remains a major reason for reoperation after multilevel ACDF. Baseline characteristics that negatively affect fusion may be obviated by careful patient selection.

Cervical Alignment Analysis Comparing Two-Level Cervical Disc Arthroplasty with Anterior Cervical Discectomy and Fusion with Anterior Plate Fixation.

OBJECTIVE: This study assesses cervical alignments after 2-level cervical disc arthroplasty (CDA) versus anterior cervical discectomy and fusion (ACDF) with anterior plate fixation. METHODS: Eighty-two patients who underwent 2-level CDA or ACDF in 2014-2019 were identified. Cervical alignment parameters were compared between the 2 cohorts. Subgroup analyses were performed to determine factors that differentiate alignment outcomes between the 2 procedures. RESULTS: Although both cohorts achieved significant focal lordosis (FL) and overall cervical lordotic (CL) gains, CDA cohorts achieved significantly greater 12-month FL gain (P = 0.022). However, in a multivariate analysis controlling for preoperative variables, FL gain was no longer significant. Although the CDA cervical sagittal vertical axis (cSVA) significantly improved at 3 (P = 0.030) and 12 (P = 0.007) months, these improvements were not superior to the ACDF cSVA. Male patients undergoing CDA achieved greater 12-month CL gain. Patients undergoing CDA with body mass index >25 kg/m2 achieved greater 12-month FL gain. Patients undergoing CDA with symptom duration >12 months achieved greater FL gain at 3 and 12 months. Patients undergoing CDA with high baseline T1 slope or cSVA achieved greater 12-month cSVA reduction. Clinical outcomes were comparable between the 2 cohorts. Unlike the ACDF group, CL gain in the CDA group was significantly correlated with the cSVA reduction, which was associated with significant improvement in the Neck Disability Index, arm pain, and 12-Item Short-Form Mental Component Scores. Heterotopic ossification was not found to significantly affect patient outcome and cervical alignment in both cohorts. CONCLUSIONS: ACDF and CDA are viable options for 2-level degenerative disc disease in carefully selected patients. Both approaches produced equivalent postoperative alignment changes in a 2-level operation.

Cervical spinal cord, root, and bony spine injuries: a closed claims analysis.

BACKGROUND: The aim of this study was to characterize cervical cord, root, and bony spine claims in the American Society of Anesthesiologists Closed Claims database to formulate hypotheses regarding mechanisms of injury. METHODS: All general anesthesia claims (1970-2007) in the Closed Claims database were searched to identify cervical injuries. Three independent teams, each consisting of an anesthesiologist and neurosurgeon, used a standardized review form to extract data from claim summaries and judge probable contributors to injury. RESULTS: Cervical injury claims (n = 48; mean ± SD age 47 ± 15 yr; 73% male) comprised less than 1% of all general anesthesia claims. When compared with other general anesthesia claims (19%), cervical injury claims were more often permanent and disabling (69%; P < 0.001). In addition, cord injuries (n = 37) were more severe than root and/or bony spine injuries (n = 10; P < 0.001), typically resulting in quadriplegia. Although anatomic abnormalities (e.g., cervical stenosis) were often present, cord injuries usually occurred in the absence of traumatic injury (81%) or cervical spine instability (76%). Cord injury occurred with cervical spine (65%) and noncervical spine (35%) procedures. Twenty-four percent of cord injuries were associated with the sitting position. Probable contributors to cord injury included anatomic abnormalities (81%), direct surgical complications (24% [38%, cervical spine procedures]), preprocedural symptomatic cord injury (19%), intraoperative head/neck position (19%), and airway management (11%). CONCLUSION: Most cervical cord injuries occurred in the absence of traumatic injury, instability, and airway difficulties. Cervical spine procedures and/or sitting procedures appear to predominate. In the absence of instability, cervical spondylosis was the most common factor associated with cord injury.