Surgical correction of severe cervical kyphosis in patients with neurofibromatosis Type 1

Surgical Treatment Outcomes of Anterior-Only Correction and Reconstruction for Severe Cervical Kyphotic Deformity with Neurofibromatosis-1: A Retrospective Study with a 5-Year Follow-Up

OBJECTIVES

Currently, anterior-only (AO), posterior-only, and combined anterior-posterior spinal fusions are common strategies for treating cervical kyphosis in patients with neurofibromatosis-1 NF-1. Nevertheless, the choice of surgical strategy remains a topic of controversy. The aim of our study is to evaluate the safety and effectiveness of anterior decompression and spinal reconstruction for the treatment of cervical kyphosis in patients with NF-1.

METHODS

Twelve patients with NF-1-associated cervical kyphotic deformity were reviewed retrospectively between January 2010 and April 2020. All patients underwent AO correction and reconstruction. The X-ray was followed up in all these patients to assess the preoperative and postoperative local kyphosis angle (LKA), the global kyphosis angle (GKA), the sagittal vertical axis, and the T1 slope. The visual analog scale score, Japanese Orthopedic Association (JOA) score, and neck disability index (NDI) score were used to evaluate the improvement inclinical symptoms. The results of the difference in improvement from preoperatively to the final follow-up assessment were assessed using a paired t-test or Mann-Whitney U-test.

RESULTS

The LKA and GKA decreased from the preoperative average of 64.42 (range, 38-86) and 35.50 (range, 10-81) to an average of 16.83 (range, -2 to 46) and 4.25 (range, -22 to 39) postoperatively, respectively. The average correction rates of the LKA and GKA were 76.11% and 111.97%, respectively. All patients had achieved satisfactory relief of neurological symptoms (p < 0.01). JOA scores were improved from 10.42 (range, 8-16) preoperatively to 15.25 (range, 11-18) at final follow-up (p < 0.01). NDI scores were decreased from an average of 23.25 (range, 16-34) preoperatively to an average of 7.08 (range, 3-15) at the final follow-up (p < 0.01).

CONCLUSION

Anterior-only correction and reconstruction is a safe and effective method for correcting cervical kyphosis in NF-1 patients. In fixed cervical kyphosis cases, preoperative skull traction should also be considered.

Correction of pediatric cervical kyphosis: our experience and systematic-literature review

BACKGROUND

Pediatric cervical kyphosis is a distinct entity with diverse etiology (congenital, syndromic, traumatic, metabolic or neoplastic). Surgical correction in pediatric population is challenging due to their growing spine and low blood volume.

PURPOSE

To analyse their presentation, surgical techniques and outcome of pediatric cervical kyphosis and systematically review the pertinent literature.

DESIGN

Retrospective study.

PATIENT SAMPLE

16 patients aged ≤ 18 years who underwent correction for cervical kyphosis between 2009 and 2021.

OUTCOME MEASURES

Nurick's grading, mJOA score and Global cobb's angle.

METHODS

Clinical parameters (Nurick grading and mJOA score) were noted from database on admission and on follow-up at 6 months. Radiological parameters of assessment included Global Cobb's angle. The C2-C7 Cobb angle was the angle of C2 vertebra lower end plate and C7 vertebra lower end plate. For C1-2 kyphosis, anterior border of C1 and anterior border of C2 angle was taken. Radiographic parameters were studied on CT and radiographs of cervical spine to assess for stability, the degree of deformity correction and fusion status at 6 months follow-up.

RESULTS

16 patients with mean age of 14.2 ± 3 years (9 syndromic, 4 post-traumatic, 2 metabolic and 1 post-laminectomy). All underwent surgical correction, 6 underwent Antero-posterior spinal fusion, 6 underwent Posterior spinal fusion and 4 underwent Anterior spinal fusion. There was significant clinical improvement postoperatively with-Nurick grade (pre vs. post: 2.8 vs. 1.8, p = 0.004), mJOA score (pre vs. post: 11.3 vs. 14, p = 0.003). There was significant deformity correction of Cobb's angle from 40.7 ± 26.5° to 14.9 ± 10° (p = 0.001). Early complications included intraoperative hemodynamic instability (3) and wound complication (1). Mean follow-up was 76.9 ± 59.3 months.

CONCLUSION

Pediatric cervical kyphosis is a debilitating condition which are managed surgically. Approach has to be individualized to the pathology and good results can be achieved. Patients should be screened for syndromic association and followed-up regularly.

Clinical features and surgical treatments of scoliosis in neurofibromatosis type 1: a systemic review and meta-analysis

BACKGROUND

Neurofibromatosis type 1 (NF 1) is an autosomal-dominant tumor predisposition genetic disease affecting approximately 1 in 3000 live births. The condition could present various manifestations ranging from skin abnormalities to neurological tumors. The musculoskeletal system could also be frequently affected, and scoliosis is the most common orthopedic manifestation. Characterized by the early-onset and rapid progression tendency, NF 1-related dystrophic scoliosis presented discrepancies from idiopathic scoliosis in terms of natural history, clinical features, and management outcomes and thus required special attention. In the current study, the authors conducted a systemic review to outline the body of evidence of the natural history, clinical characteristics, surgical outcomes, and surgical complications of NF 1-induced scoliosis, aiming to provide an elucidative insight into this condition.

METHOD

Systemic review and meta-analysis were conducted according to the latest Preferred Reporting Items for Systematic Reviews Meta-Analyses (PRISMA) guidelines. The search was performed in Medline, Embase, and Web of Science Core Collection up to December 27, 2022, using related keywords. Clinical features such as frequencies, segmental involvement, and hereditary information were summarized and described qualitatively. Meta-analysis was conducted using R software and the 'meta' package to yield an overall outcome of efficacy and safety of surgical management, precisely, spinal fusion procedure and growing rods procedure. Corrective rate of Cobb angle, sagittal kyphosis angle, and T1-S1 length post-operative and at the last follow-up was used to evaluate the efficacy, and the occurrence of surgery-related complications was used to evaluate the safety.

RESULT

A total of 37 articles involving 1023 patients were included. Approximately 26.6% of the NF 1 patients would present with scoliosis. Patients tend to develop scoliosis at an earlier age. The thoracic part turned out to be the most affected segment. No obvious correlation between scoliosis and genotype or hereditary type was observed. Both spinal fusion and growing rod surgery have shown acceptable treatment outcomes, with spinal fusion demonstrating better performance in terms of effectiveness and safety. The growing rods technique seemed to allow a better lengthening of the spine. The mainstay post-operative complications were implant-related complications but could be managed with limited revision surgery. Severe neurological deficits were rarely reported.

CONCLUSION

Scoliosis, especially the subtype characterized by dystrophic bony changes, is a significant orthopedic manifestation of NF1. It has an early onset, a tendency to persistently and rapidly progress, and is challenging to deal with. The current review outlines the available evidence from the perspective of natural history, clinical features, and the treatment efficacy and safety of the mainstay surgical options. Patients with NF1 scoliosis will benefit from a better understanding of the disease and evidence based treatment strategies.

Acute Progressive Pediatric Post-Traumatic Kyphotic Deformity

Cervical kyphosis is a rare entity with challenging management due to the limitations of pediatric age, along with a growing spine. The pathogenesis is made up of a large group of congenital, syndromic and acquired deformities after posterior element deterioration or as a result of previous trauma or surgery. In rare progressive cases, kyphotic deformities may result in severe "chin-on-chest" deformities with severe limitations. The pathogenesis of progression to severe kyphotic deformity after minor hyperflexion trauma is not clear without an obvious MR pathology; it is most likely multifactorial. The authors present the case of a six-month progression of a pediatric cervical kyphotic deformity caused by a cervical spine hyperflexion injury, and an MR evaluation without the pathology of disc or major ligaments. Surgical therapy with a posterior fixation and fusion, together with the preservation of the anterior growing zones of the cervical spine, are potentially beneficial strategies to achieve an excellent curve correction and an optimal long-term clinical outcome in this age group.

Severe cervical kyphosis in a young adult with fixed dropped head syndrome, dysphagia, and myelopathy: A case report

BACKGROUND

Several reports exist on syndromic cervical kyphosis in the elderly, including dropped head syndrome, degenerative spondylosis, and neurological diseases; however, it is rarely reported in young patients especially with complications.

CASE PRESENTATION

We describe a case of a 25-year-old man who presented severe cervical kyphosis with dropped head syndrome, horizontal-gaze disorder, dysphagia, and myelopathy. The etiology of this cervical kyphosis was suspected to be as a result of a combination of an underlying developmental disorder and habitual, long-term cervical flexion postures while engaging in smartphone games. Combined anterior and posterior surgeries resulted in good outcomes and improved the patient's quality of life remarkably.

CONCLUSION

Cervical kyphosis awareness in young patients is crucial. Moreover, combined anterior and posterior approach provides secure, good results, and with less sequelae.

Effect of cervical suspensory traction in the treatment of severe cervical kyphotic deformity

Objective

This study aimed to investigate a new noninvasive traction method on the treatment of severe cervical kyphotic deformity.

Methods

The clinical data of patients with severe cervical kyphosis (Cobb > 40°) treated in Peking University Third Hospital from March 2004 to March 2020 were retrospectively summarized. 46 cases were enrolled, comprising 27 males and 19 females. Fifteen patients underwent skull traction, and 31 patients underwent suspensory traction. Among them, seven used combined traction after one week of suspensory traction. Bedside lateral radiographs were taken every two or three days during traction. The cervical kyphosis angle was measured on lateral radiographs in and extended position at each point in time. The correction rate and evaluated Japanese Orthopedic Association (JOA) scoring for the function of the spinal cord were also measured. The data before and after the operation were compared with paired sample t-test or Wilcoxon signed-rank test.

Results

No neurological deterioration occurred during the skull traction and the cervical suspensory traction. There were 12 patients with normal neurological function, and the JOA score of the other 34 patients improved from 11.5 ± 2.8 to 15.4 ± 1.8 at the end of follow up (P < 0.05). The average kyphotic Cobb angle was 66.1° ± 25.2, 28.7° ± 20.1 and 17.4° ± 25.7 pre-traction, pre-operative, and at the final follow-up, respectively (P < 0.05). The average correction rate of skull traction and suspensory traction was 34.2% and 60.6% respectively. Among these, the correction rate of patients with simple suspensory traction was 69.3%. For patients with a correction rate of less than 40% by suspensory traction, combined traction was continued, and the correction rates after suspensory traction and combined traction were 30.7% and 67.1% respectively.

Conclusions

Pre-correction by cervical suspensory traction can achieve good results for severe cervical kyphotic deformity, with no wound and an easy process. Combined traction is effective for supplemental traction after suspensory traction.

Surgical challenges and functional outcomes in dystrophic cervical kyphosis in Neurofibromatosis -1: an institutional experience

OBJECTIVE

Dystrophic cervical kyphosis secondary to neurofibromatosis 1 (NF1) is rarely reported. The primary objective is to highlight the clinical presentation and surgical outcomes based on clinical and biomechanical parameters. The secondary objective is to highlight the early and late complications of these surgeries.

METHODS

The hospital records of six patients operated between 2008 and 2018 were retrospectively reviewed with a minimum follow-up of 24 months. Besides demographics information, radiological findings and operative details, the outcome measures reported were neurological (MJOA score, Nurick scale), pain (VAS score) and operative complications.

RESULTS

The mean age of patients was 15.1 years (8-32 years). The average kyphotic vertebra involved-3.6 bodies (range 2-5 bodies) with four patients showing intraspinal anomaly-neurofibromas, dural ectasia. Clinically, patients improved postoperatively with-VAS (pre vs. post-: 6.6 vs. 2.6, p - < 0.05), MJOA score (pre vs. post: 10.3 vs. 13.3, p - < 0.05), Nurick grade (pre vs. post: 3.5 vs. 2.1, p - < 0.05). There was significant deformity correction from 66.8° to 20.7° (p value < 0.031), mean T1 Slope (pre vs. post - 1.8 ± 20.4 to 0.6 ± 12.8, p value - < 0.43). Mean blood loss encountered was 1800 ± 434.6 cc; however, patients with paraspinal neurofibromas reported greater blood loss. Late complications included pseudoarthrosis (1), C5 palsy (1) and junctional kyphosis (1). Vertebral dysplasia and erosions continued in all patients post-operatively.

CONCLUSIONS

Antero-posterior approach provides circumferential decompression and better sagittal balance correction. Cervical spine must be screened in all NF-1 patients and followed up regularly to assess for dystrophic changes.

Vital Role of In-House 3D Lab to Create Unprecedented Solutions for Challenges in Spinal Surgery, Practical Guidelines and Clinical Case Series

For decades, the advantages of rapid prototyping for clinical use have been recognized. However, demonstrations of potential solutions to treat spinal problems that cannot be solved otherwise are scarce. In this paper, we describe the development, regulatory process, and clinical application of two types of patient specific 3D-printed devices that were developed at an in-house 3D point-of-care facility. This 3D lab made it possible to elegantly treat patients with spinal problems that could not have been treated in a conventional manner. The first device, applied in three patients, is a printed nylon drill guide, with such accuracy that it can be used for insertion of cervical pedicle screws in very young children, which has been applied even in semi-acute settings. The other is a 3D-printed titanium spinal column prosthesis that was used to treat progressive and severe deformities due to lysis of the anterior column in three patients. The unique opportunity to control size, shape, and material characteristics allowed a relatively easy solution for these patients, who were developing paraplegia. In this paper, we discuss the pathway toward the design and final application, including technical file creation for dossier building and challenges within a point-of-care lab.

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.

Halo traction combined with posterior-only approach correction for cervical kyphosis with Neurofibromatosis-1: minimum 2 years follow-up

Background

Surgical management of cervical kyphosis in patients with NF-1 is a challenging task. Presently, anterior-only (AO), posterior-only (PO) and combined anterior-posterior (AP) spinal fusion are common surgical strategies. However, the choice of surgical strategy and application of Halo traction remain controversial. Few studies have shown and recommended posterior-only approach for cervical kyphosis correction in patients with NF-1. The aim of this study is to evaluate the safety and the effectiveness of halo Traction combined with posterior-only approach correction for treatment of cervical kyphosis with NF-1.

Methods

Twenty-six patients with severe cervical kyphosis due to NF-1 were reviewed retrospectively between January 2010 and April 2018. All the cases underwent halo traction combined with posterior instrumentation and fusion surgery. Correction result, neurologic status and complications were analyzed.

Results

In this study, cervical kyphosis Cobb angle decreased from initial 61.3 ± 19.7 degrees to postoperative 10.6 ± 3.7 degrees (P<0.01), with total correction rate of 82.7%, which consist of 45.8% from halo traction and 36.9% from surgical correction. JOA scores were improved from preoperative 13.3 ± 1.6 to postoperative 16.2 ± 0.7 (P<0.01). Neurological status was also improved. There was no correction loss and the neurological status was stable in mean 43 months follow-up. Three patients experienced minor complications and one patient underwent a second surgery.

Conclusion

Halo traction combined with PO approach surgery is safe and effective method for cervical kyphosis correction in patients with NF-1. A satisfied correction result, and successful bone fusion can be achieved via this procedure, even improvement of neurological deficits can also be obtained. Our study suggested that halo traction combined with PO approach surgery is another consideration for cervical kyphosis correction in patients with NF-1.

Staged Management of Cervicothoracic Lordosis and Scoliosis in an Emery-Dreifuss VI Muscular Dystrophy Patient: A Case Report

CASE

We report the case of an 18-year-old man with extreme cervicothoracic lordosis and a progressive scoliosis secondary to Emery-Dreifuss Type VI muscular dystrophy. In a staged fashion, the patient underwent posterior cervical muscle release, halo-gravity traction, and posterior instrumented spinal fusion from C3-L4 with multiple posterior column osteotomies. The patient was followed over 2 years postoperatively with restoration of normal spinal alignment in both the coronal and sagittal profiles.

CONCLUSION

This is the first reported case illustrating the gradual correction of severe lordoscoliosis in this patient population.

Atlantoaxial Dislocation Associated with Type 1 Neurofibromatosis: Case Report and Review of the Literature

BACKGROUND

Neurofibromatosis type 1 (NF-1) is an autosomal dominant genetic condition in which spinal deformities are commonly involved. However, atlantoaxial dislocation in NF-1 is extremely rare. A review of the English literature has identified only 10 cases in 8 reports. We report a rare case involving NF-1 associated with severe atlantoaxial dislocation.

CASE DESCRIPTION

A 22-year-old woman with NF-1 presented with progressive numbness in her left upper and lower extremities and gait difficulty for 2 months. She was treated with skull traction and partial reduction was achieved. Initial surgical strategy was posterior fusion using a screw-rod-wire construct, but significant bleeding was encountered during the surgery. To shorten the procedure time, a single sublaminar wire of the atlas was tied to the spinous process of the axis to accomplish the reduction and fixation. C1-C2 fusion was performed using iliac crest autograft. The patient had significant improvement of neurologic deficit after surgery. Due to relatively poor fixation provided by the wire, she was requested to rest in bed for the first 3 months and to wear a cervical orthosis for the next 3 months. Solid bony fusion was confirmed by radiologic examination at 18-month follow-up.

CONCLUSIONS

Atlantoaxial dislocation is a rare complication in NF-1 patients. Surgical reduction combined with fusion is essential for a good outcome. Spine surgeons should also be knowledgeable about the possibility of significant hemorrhage before surgery.

Two surgical strategies for treating multilevel cervical spondylotic myelopathy combined with kyphotic deformity

This study compared the surgical outcomes of two surgical methods for treating multilevel cervical spondylotic myelopathy (MCSM) combined with cervical kyphotic deformity (CKD): (1) the ELTA method consisted of expansive open-door laminoplasty (EOLP) followed by three-segment anterior cervical discectomy fusion (ACDF), and (2) the LAPI method consisted of long-segment ACDF followed by long-level posterior instrumented fusion (PIF). Surgical treatment of CKD combined with MCSM remains challenging. Surgical considerations should include adequate spinal cord decompression and restoration of satisfactory cervical sagittal alignment (CSA). In certain situations, a solid PIF structure is vital to prevent failure.We included 105 patients who underwent the aforementioned surgical methods for MCSM combined with CKD from January 2013 to December 2017. The minimum follow-up period was 1 year. Comparative analysis was performed to compare the two surgical strategies' preoperative and postoperative functional outcomes, including a visual analog scale for neck pain, neck disability index, the Japanese Orthopedic Association cervical myelopathy score, and the Nurick score, as well as the CSA radiographic outcomes, including C2-7 Cobb angle, C2-7 sagittal vertical axis, and C7 slope. The risk factors related to reduced improvement in functional status were analyzed.A total of 63 patients underwent ELTA and 42 patients underwent LAPI. Improvements in functional outcomes were considerable in both groups. The mean C2-7 Cobb angle was restored from 7.4° ± 2.1° kyphosis to 8.8° ± 4.7° lordosis in the ELTA group and from 15.3° ± 4.2° kyphosis to 15.8° ± 8.1° lordosis in the LAPI group. The maximal correction angle was 22.6° in the ELTA group and 42.6° in the LAPI group.Although changes in CSA seemed to be significantly correlated with improvements of functional status, the ELTA and LAPI methods were both effective for treating MCSM combined with CKD, when appropriately selected. The ELTA method was indicated for MCSM patients who had a low degree of CKD, whereas the LAPI method was indicated for MCSM patients who had poor function scores and a high degree of CKD.

Halo-gravity traction for the treatment of pediatric cervical spine disorders

OBJECTIVE

Halo-gravity traction (HGT) is an effective and safe method for gradual correction of severe cervical deformities in adults. However, the literature is limited on the use of HGT for cervical spine deformities that develop in children. The objective of the present study was to evaluate the safety and efficacy of HGT for pediatric cervical spine deformities.

METHODS

Twenty-eight patients (18 females) whose mean age was 11.3 ± 5.58 years (range 2-24.9 years) underwent HGT. Common indications included kyphosis (n = 12), rotatory subluxation (n = 7), and basilar invagination (n = 6). Three children (11%) received traction to treat severe occipitocervical instability. For these 3 patients, traction combined with a halo vest, with bars attached rigidly to the vest, but with the ability to slide through the connections to the halo crown, was used to guide the corrective forces and moments in a specific and controlled manner. Patients ambulated with a wheelchair or halo walker under constant traction. Imaging was done before and during traction to evaluate traction efficacy. The modified Clavien-Dindo-Sink classification was used to categorize complications.

RESULTS

The mean duration of HGT was 25 days (IQR 13-29 days), and the mean traction was 29% ± 13.0% of body weight (IQR 19%-40% of body weight). The mean kyphosis improved from 91° ± 20.7° (range 64°-122°) to 56° ± 17.6° (range 32°-96°) during traction and corresponded to a mean percentage kyphosis correction of 38% ± 13.8% (range 21%-57%). Twenty-five patients (89%) underwent surgical stabilization, and 3 patients (11%) had rotatory subluxation that was adequately reduced by traction and were treated with a halo vest as their definitive treatment. The mean hospital stay was 35 days (IQR 17-43 days).Nine complications (32%) occurred: 8 grade I complications (28%), including 4 cases of superficial pin-site infection (14%) and 4 cases of transient paresthesia (14%). One grade II complication (4%) was seen in a child with Down syndrome and a preexisting neurological deficit; this patient developed flaccid paralysis that rapidly resolved with weight removal. Six cases (21%) of temporary neck discomfort occurred as a sequela of a preexisting condition and resolved without treatment within 24-48 hours.

CONCLUSIONS

HGT in children is safe and effective for the gradual correction of cervical kyphosis, atlantoaxial subluxation, basilar invagination, and os odontoideum. Cervical traction is an additional tool for the pediatric spine surgeon if uncertainties exist that the spinal alignment required for internal fixation and deformity correction can be safely achieved surgically. Common complications included grade I complications such as superficial pin-site infections and transient paresthesias. Halo vest gravity traction may be warranted in patients with baseline neurological deficits and severe occipitocervical instability to reduce the chance of catastrophic movement.

Halo Fixator and Halo Traction - Value for the Treatment of Spinal Disorders in Childhood

The application of the Halo fixateur in case of spinal pathologies in childhood is a standardized technique. The halo fixateur may be used for treatment of injuries of the cervical spine, for additional stabilization following extended surgery at the cervical spine and their transitional regions as well as to achieve preoperative reduction in case of severe and rigid deformity. These indications are, referred to the early age, rare. However, the successful use of the Halo fixateur presumes a certain familiarity with the device and experiences regarding the underlying diseases to minimize related risks and to avoid possible complications. In this article the use and specific features regarding the application of the halo fixateur in childhood based on presented cases and the literature will be discussed.

Preoperative and Intraoperative Skull Traction Combined with Anterior-Only Cervical Operation in the Treatment of Severe Cervical Kyphosis (>50 Degrees)

OBJECTIVE

To evaluate the clinical and radiographic outcomes of an anterior-only approach for the correction of severe cervical kyphotic deformities.

METHODS

We performed a retrospective study of 33 consecutive patients with severe cervical kyphosis treated with an anterior cervical operation and preoperative and intraoperative skull traction. Cobb angle, kyphosis index (KI), kyphosis level, C2-7 sagittal vertical axis (SVA), and T1 slope were measured. The preoperative and postoperative Japanese Orthopedic Association (JOA) scores, visual analog scale (VAS) score for neck pain, Neck Disability Index (NDI) scores, and cervical alignment were compared.

RESULTS

The mean angle of the kyphosis was 83.2 ± 20.4°. The mean Cobb angle of the operative region was 71.7 ± 18.5° preoperation, which was reduced to 10.6 ± 5.7° postoperation (mean correction, 85.2%). The mean KI was 75.1 ± 18.2 preoperation, which was reduced to 14.4 ± 9.1 postoperation (mean correction, 80.8%). The preoperative and postoperative mean C2-7 Cobb angle was 53.8 ± 16.5° and 14.7 ± 7.6°, respectively. The preoperative and postoperative mean C2-7 SVA was 3.9 ± 14.5 mm and 12.8 ± 7.3 mm, respectively. The preoperative and postoperative mean T1 slope was -9.4 ± 15.7° and 7.3 ± 13.1°, respectively. The average postoperative C2-7 Cobb angle, Cobb angle of the operative region, KI, C2-7 SVA, and T1 slope changed significantly compared with preoperative values (P < 0.05). The average postoperative JOA, VAS, and NDI scores improved significantly compared with preoperative scores (P < 0.05).

CONCLUSIONS

Preoperative and intraoperative skull traction combined with anterior-only cervical operation may be a safe and effective technique for treating severe cervical kyphosis. If the postoperative correction is >80%, sufficient decompression could be achieved.

Cervical Spine Deformity: Indications, Considerations, and Surgical Outcomes

Cervical spinal deformity (CSD) in adult patients is a relatively uncommon yet debilitating condition with diverse etiologies and clinical manifestations. Similar to thoracolumbar deformity, CSD can be broadly divided into scoliosis and kyphosis. Severe forms of CSD can lead to pain; neurologic deterioration, including myelopathy; and cervical spine-specific symptoms such as difficulty with horizontal gaze, dysphagia, and dyspnea. Recently, an increased interest is shown in systematically studying CSD with introduction of classification schemes and treatment algorithms. Both major and minor complications after surgical intervention have been analyzed and juxtaposed to patient-reported outcomes. An ongoing effort exists to better understand the relationship between cervical and thoracolumbar spinal alignment, most importantly in the sagittal plane.

A case report of revision occipital-cervical fusion after atlanto-axial instrumentation failure for neurofibromatosis type I

BACKGROUND

Neurofibromatosis type 1 is an autosomal dominant genetic disease with characteristic café-au-lait spots, neurofibroma, and dystrophic changes in the bones. However, complications involving atlanto-axial dislocation are rare.

CASE PRESENTATION

We report a case of neurofibromatosis with atlanto-axial dislocation. The chief complaints were numbness of the upper limb and gait disturbance. We performed short fusion using the Brooks method. However, recurrence of the dislocation was found after 5 months recovery, and the patient underwent posterior fusion from the occipital bone to C4. Thereafter, she had a good postoperative course.

CONCLUSIONS

Neurofibromatosis patients often exhibit a low bone mineral density because of dystrophic changes, and are prone to fragile bones. In the present case, the use of long fusion at the first surgery may have helped to form a strong fusion of fragile bone.

Acute progressive adolescent idiopathic cervical kyphosis: case report

Acute progressive adolescent idiopathic cervical kyphosis (AICK) is rare, and its treatment strategy is controversial. The authors present a case of AICK successfully treated with preoperative halo-gravity traction, followed by combined anterior-posterior surgery. A 15-year-old girl with no relevant past or family history presented with axial neck pain without any cause. A few months after the development of cervical myelopathy, cervical kyphosis progressed to 71° despite conservative treatment. CT scanning demonstrated osteophyte formation at the anterior aspect of the vertebral body. MRI showed a forward migration of the spinal cord with a ratio (C/M ratio) between the anteroposterior diameter of the medulla-pons junction and the spinal cord at the apex of the kyphosis of 0.27. After 2 weeks of preoperative halo-gravity traction, anterior release and posterior fusion was performed. After surgery, cervical kyphosis was corrected to 0°, and cervical myelopathy improved. One year after surgery, the patient was neurologically intact, and bony union and improved cervical alignment were observed. Preoperative halo-gravity traction followed by combined anterior-posterior surgery led to safe and effective correction. Osteophyte formation at the anterior aspect of the vertebral body and the C/M ratio were useful in predicting the progression of AICK.

Management of Cervical Instability as a Complication of Neurofibromatosis Type 1 in Children: A Historical Perspective With a 40-Year Experience

STUDY DESIGN

Literature review with supplementary case examples.

OBJECTIVES

The objective of this article was to review neurofibromatosis type 1 (NF1) and the associated spinal pathology with a focus on the disorder's manifestations in the immature cervical spine.

SUMMARY OF BACKGROUND DATA

NF1 is one of the most common inheritable genetic disorders. The disorder is associated with spinal deformities, long bone dysplasia, and osteoporosis. The manifestations of NF1 in the cervical spine commonly include instability secondary to kyphosis, neurofibromas, and dural ectasia.

METHODS

Literature relevant to the evaluation and management of NF1 in the cervical spine was reviewed using the PubMed/NCBI database with a focus on recent clinical studies. The review was supplemented with a historical perspective and patient cases.

RESULTS

The prevalence of NF1 cervical spine lesions is difficult to define because many patients may be asymptomatic. Symptoms of cervical kyphosis can include pain or nerve deficits but some have a surprisingly high tolerance for deformity and may have frank dislocation of one vertebral body over another (spondyloptosis) with few associated symptoms. Cervical radiographs should be obtained in patients requiring traction, surgery, or intubation, and those with neck pain or symptoms that suggest spinal neurofibromas. Patients with progressive symptoms should be offered surgery. Careful planning is required because many patients will have small, dysplastic vertebral bodies, thin posterior elements, plexiform neurofibromas, or dural ectasia. The decision to use preoperative traction will vary from patient to patient. Combined anterior-posterior fusion is recommended for most cases of severe symptomatic kyphosis, and the fusion should extend from parallel to parallel vertebrae (or six or more levels). Anterior or posterior fusion alone may be an alternative for skeletally mature patients with smaller, flexible curves.

CONCLUSIONS

Spinal deformity is the most common musculoskeletal manifestation of NF1. Cervical lesions are frequently asymptomatic, but patients with thoracolumbar scoliosis, dystrophic features, or a history of laminectomy should have the cervical spine carefully evaluated. For severe and progressive kyphotic deformities, most authors recommend a period of traction followed by a combined anterior-posterior fusion that is instrumented from parallel to parallel vertebra (or six or more levels). Close follow-up is very important because complications and progression are frequent.

National Trends in Spinal Fusion Surgery for Neurofibromatosis

STUDY DESIGN

Analysis of a national database.

OBJECTIVE

To analyze trends in spinal fusion surgery for neurofibromatosis type I (NF-1) patients and to compare the surgical approaches.

SUMMARY OF BACKGROUND DATA

The preferred surgical approach for fusion treatment of spinal deformity in NF is not well established.

METHODS

We identified 548 patients with a diagnosis of NF-1 who had received spinal fusion surgery between 2003 and 2014. We compared posterior spinal fusion (PSF), anterior-posterior spinal fusion (APSF), and anterior spinal fusion with respect to patient demographics, institutional characteristics, in-hospital complications, and hospitalization lengths and costs. Significance was set at a value of p less than .05.

RESULTS

The number of spinal fusions for NF-1 significantly increased (p = .02) over the study period. The rate of PSF surgeries increased 2.9-fold, whereas the rate of APSF surgeries decreased 2.2-fold. There was also a significant association between the location of the fusion and surgical approach (p<.01), with 66% of ASF cases being cervical spine cases. Compared with patients undergoing PSF and ASF, patients undergoing APSF were significantly younger (p<.01) and had significantly higher hospitalization lengths and costs (p<.01). APSF costs were $180,714 as compared to $144,027 for PSF and $105,312 for ASF.

CONCLUSIONS

There have been significant increases in the rate of spinal fusion surgeries for NF-1 patients. Surgical treatment has shifted over the years and is dependent on the location of the deformity. Patients undergoing APSF are significantly younger.

LEVEL OF EVIDENCE

Level III.

Clinical outcomes of anterior correction and reconstruction for neurofibromatosis-associated severe cervical kyphotic deformity

PURPOSE

To assess the clinical outcome of anterior correction and reconstruction for severe cervical kyphotic deformity due to neurofibromatosis type 1 (NF-1).

METHODS

In this study, we reviewed a series of seven patients who underwent anterior procedures for correction of NF-1-associated cervical kyphotic deformity. After continuous preoperative skull traction, all patients received anterior corpectomy and fusion (ACCF), anterior discectomy and fusion (ACDF), or combined ACCF and ACDF for surgical correction and reconstruction. Pre- and postoperative local and global Cobb angles, correction rate, sagittal vertical axis (SVA), and T1-slope were assessed by X-ray. Japanese Orthopaedic Association (JOA) score, JOA recovery rate, visual analog scale (VAS), and Neck Disability Index (NDI) scores were recorded to assess the outcome.

RESULTS

Kyphosis was corrected successfully in all patients in terms of local and global Cobb angles (P < 0.05), with a correction rates of 83.1% (range, 66.0 to 115.5%) and 88.6% (range, 61.1 to 125.0%), respectively. JOA scores of patients were improved from preoperative 10.4 (range, 6 to 14) to postoperative 15.4 (range, 14 to 17), with a recovery rate as 77.6% (range, 66.7 to 100%). NDI scores were reduced from preoperative 25.1 (range, 13 to 35) to postoperative 8.7 (range, 5 to 12). VAS scores were reduced from preoperative 7.0 (range, 4 to 9) to postoperative 2.3 (range, 1 to 3).

CONCLUSION

This study has demonstrated that anterior correction and reconstruction is an alternative option for the treatment of NF-1-associated severe cervical kyphosis when deformity is localized, flexible, or fixed.

Correction of Progressive Severe Cervical Kyphosis in a 21-Month-Old Patient With NF1: Surgical Technique and Review of Literature

BACKGROUND

Severe cervical kyphosis in the setting of neurofibromatosis type 1 (NF1) is a rare manifestation of the disease in the pediatric population. Dystrophic and immature bone complicate the placement of hardware necessary for surgical correction of alignment and a review of the literature yields 4 cases of pediatric patients with NF1 requiring surgical intervention in which the youngest patient was 10 yr old.

OBJECTIVE

To report the case of an 11-mo-old female with NF1 who presented with a plexiform cervical neurofibroma and focal cervical kyphosis. A comprehensive review of the literature and a detailed description of nonsurgical and surgical management for this patient population is described.

METHODS

A literature review was completed for article reviewing management of pediatric patients with cervical spine injuries and NF1. The patient's chart was reviewed and the patient was followed for a year to provide adequate follow-up. Institutional Review Board (IRB)/ethics committee approval and patient consent were neither required nor sought for this study.

RESULTS

The literature was reviewed, summarized, and utilized for operative planning and postoperative management. Postoperative imaging and 1-yr follow-up imaging showed anterior construct and lateral mass fusion, restoration of cervical alignment, and no neurological deficits.

CONCLUSION

This is the youngest reported patient to have surgical cervical kyphosis correction in the setting of NF1. A review of the literature helped develop a long-term plan and shape a novel same-day front-back-front approach to restore alignment that will be of use to teams managing these complex patients in the future.

Buckling Collapse of Midcervical Spine Secondary to Neurofibromatosis

Buckling collapse is the term typically used to describe severe kyphosis >100 degrees, characteristically seen in thoracolumbar tuberculosis. Neurofibromatosis is rarely associated with severe cervical kyphosis. Dystrophic changes in vertebra make surgical correction and fusion challenging. Single-stage cervical osteotomies (e.g., pedicle subtraction osteotomy, vertebral column resection) are commonly done in cervicothoracic junction. However, it is technically challenging and associated with high risk of vertebral artery injury, neural injury, etc. when performed in higher cervical spine. Hence in our case we did a staged procedure performing circumferential osteotomy for buckling kyphosis in the midcervical spine. Because it involved midcervical spine and there was no chin-to-chest deformity, we preferred the anterior-posterior-anterior sequence.

Pharmacologically targeting beta-catenin for NF1 associated deficiencies in fracture repair

Patients with Neurofibromatosis type 1 display delayed fracture healing and the increased deposition of fibrous tissue at the fracture site. Severe cases can lead to non-union and even congenital pseudarthrosis. Neurofibromatosis type 1 is caused by a mutation in the NF1 gene and mice lacking the Nf1 gene show a fracture repair phenotype similar to that seen in patients. Tissue from the fracture site of patients with Neurofibromatosis type 1 and from mice deficient in the Nf1 gene both show elevated levels of β-catenin protein and activation of β-catenin mediated signaling. Constitutively elevated β-catenin leads to a delayed and fibrous fracture repair process, and (RS)-5-methyl-1-phenyl-1,3,4,6-tetrahydro-2,5-benzoxazocine (Nefopam, a centrally-acting, non-narcotic analgesic agent) inhibits β-catenin mediated signaling during skin wound repair. Here we investigate Nefopam's potential as a modulator of bone repair in mice deficient in Nf1. Mice were treated with Nefopam and investigated for bone fracture repair. Bone marrow stromal cells flushed from the long bones of unfractured mice were treated with Nefopam and investigated for osteogenic potential. Treatment with Nefopam was able to lower the β-catenin level and the Axin2 transcript level in the fracture calluses of Nf1 deficient mice. Cultures from the bone marrow of Nf1^-/- mice had significantly lower osteoblastic colonies and mineralized nodules, which was increased when cells were cultured in the presence of Nefopam. Fracture calluses were harvested and analyzed 14days and 21days after injury. Nf1^-/- calluses had less bone, less cartilage, and higher fibrous tissue content than control calluses. Treatment with Nefopam increased the bone and cartilage content and decreased the fibrous tissue content in Nf1^-/- calluses. These findings present a potential treatment for patients with Neurofibromatosis 1 in the context of bone repair. Since Nefopam is already in use in patient care, it could be rapidly translated to the clinical setting.

Coronal Multiplane Reconstructed Computed Tomography Image Determining Lateral Vertebral Notch-Referred Pedicle Screw Entry Point in Subaxial Cervical Spine: A Preclinical Study

OBJECTIVE

To evaluate feasibility of computed tomography (CT) coronal multiplane reconstruction image (CMRI) to determine subaxial cervical pedicle screw (PS) entry point and guide lateral vertebral notch (LVN)-referred technique for subaxial cervical PS insertion.

METHODS

Cervical CT scans were performed in 40 volunteers. PS entry point was determined by quantitating PS entry point related to LVN on CMRI. Pedicle mediolateral angle (α) and cephalocaudad angle (β) were also measured to guide the trajectory of PS insertion. Based on these quantitations, 12 human cadaveric subaxial cervical pedicles were inserted with PS referring to LVN. Cortical integrity of each pedicle was evaluated after dissecting the cadaveric vertebrae one by one and confirmed by radiography and CT. The cortical penetration and PS position were classified into 4 grades: 0 (excellent position), I (good position), II (fair position), and III (poor position).

RESULTS

On CT CMRI, PS entry point was consistently located approximately 2.2 mm medial to LVN from C3 to C7 and approximately 1.4 mm lower to LVN from C3 to C6, but 1.2 mm higher at C7. Bilateral α angle and β angle showed substantial decrease from cranial to caudal. Cortical integrity of PS positions was excellent and good in 88.33%, fair in 8.33%, and poor in 3.33%.

CONCLUSIONS

CMRI is reliable for determining subaxial cervical PS entry point. LVN is a consistent landmark for the notch-referred technique, which is a practical and easy to master technique for subaxial cervical spine PS insertion.

The accuracy of the lateral vertebral notch-referred pedicle screw insertion technique in subaxial cervical spine: a human cadaver study

STUDY DESIGN

This is a cadaver specimen study to confirm new pedicle screw (PS) entry point and trajectory for subaxial cervical PS insertion.

OBJECTIVE

To assess the accuracy of the lateral vertebral notch-referred PS insertion technique in subaxial cervical spine in cadaver cervical spine.

BACKGROUNDS

Reported morphometric landmarks used to guide the surgeon in PS insertion show significant variability. In the previous study, we proposed a new technique (as called "notch-referred" technique) primarily based on coronal multiplane reconstruction images (CMRI) and cortical integrity after PS insertion in cadavers. However, the PS position in cadaveric cervical segment was not confirmed radiologically. Therefore, the difference between the pedicle trajectory and the PS trajectory using the notch-referred technique needs to be illuminated.

METHODS

Twelve cadaveric cervical spines were conducted with PS insertion using the lateral vertebral notch-referred technique. The guideline for entry point and trajectory for each vertebra was established based on the morphometric data from our previous study. After 3.5-mm diameter screw insertion, each vertebra was dissected and inspected for pedicle trajectory by CT scan. The pedicle trajectory and PS trajectory were measured and compared in axial plane. The perforation rate was assessed radiologically and was graded from ideal to unacceptable: Grade 0 = screw in pedicle; Grade I = perforation of pedicle wall less than one-fourth of the screw diameter; Grade II = perforation more than one-fourth of the screw diameter but less than one-second; Grade III = perforation more than one-second outside of the screw diameter. In addition, pedicle width between the acceptable and unacceptable screws was compared.

RESULTS

A total of 120 pedicle screws were inserted. The perforation rate of pedicle screws was 78.3% in grade 0 (excellent PS position), 10.0% in grade I (good PS position), 8.3% in grade II (fair PS position), and 3.3% in grade III (poor PS position). The overall accepted accuracy of pedicle screws was 96.7% (Grade 0 + Grade I + Grade II), and only 3.3% had critical breach. There was no statistical difference between the pedicle trajectory and PS trajectory (p > 0.05). Compared to the pedicle width (4.4 ± 0.7 mm) in acceptably inserted screw, the unacceptably screw is 3.2 ± 0.3 mm which was statistically different (p < 0.05).

CONCLUSION

The accuracy of the notch-referred PS insertion in cadaveric subaxial cervical spine is satisfactory.

Outcomes of Spinal Fusion for Cervical Kyphosis in Children with Neurofibromatosis

BACKGROUND

Cervical kyphosis may occur with neurofibromatosis type I (NF1) and is often associated with vertebral dysplasia. Outcomes of cervical spinal fusion in patients with NF1 are not well described because of the rarity of the condition. We aimed to (1) characterize the clinical presentation of cervical kyphosis and (2) report the outcomes of posterior and anteroposterior cervical fusion for the condition in these children.

METHODS

The medical records and imaging studies of 22 children with NF1 who had undergone spinal fusion for cervical kyphosis (mean, 67°) at a mean age of 11 years and who had been followed for a minimum of 2 years were reviewed.

RESULTS

Thirteen children presented with neck pain; 10, with head tilt; 9, with a previous cervical laminectomy or fusion; and 5, with a neurologic deficit. Two patients had spontaneous dislocation of the mid-cervical spine without a neurologic deficit. Eleven had scoliosis, with the major curve measuring a mean of 61°. Nine patients underwent posterior and 13 underwent anteroposterior surgery. Twenty-one received spinal instrumentation, and 1 was not treated with instrumentation. Preoperative halo traction was used for 9 patients, and it reduced the mean preoperative kyphosis by 34% (p = 0.0059). At the time of final follow-up, all spinal fusion sites had healed and the cervical kyphosis averaged 21° (mean correction, 69%; p < 0.001). The cervical kyphosis correction was significantly better after the anteroposterior procedures (83%) than after the posterior-only procedures (58%) (p = 0.031). Vertebral dysplasia and erosion continued in all 17 patients who had presented with dysplasia preoperatively. Thirteen patients had complications, including 5 new neurologic deficits and 8 cases of junctional kyphosis. Nine patients required revision surgery. Junctional kyphosis was more common in children in whom ≤5 levels had been fused (p = 0.054).

CONCLUSIONS

Anteroposterior surgery provided better correction of cervical kyphosis than posterior spinal fusion in children with NF1. Erosion of vertebral bodies continued during the postoperative follow-up period in all patients who had presented with dysplastic changes preoperatively. The cervical spine should be screened in all children with NF1. Fusion should include at least 6 levels to prevent junctional kyphosis.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Posterior 2-Level Vertebral Column Resection for the Treatment of Progressive Rotational Dislocation in Kyphoscoliotic Deformities

OBJECTIVE

Progressive rotational dislocation of the spine is rare and surgical treatment is challenging. Few reports have described surgical decompression, fusion, and partial correction by traditional 2-stage anterior decompression and the posterior fixation technique. The goal of this retrospective study was to report a series of 6 patients with this deformity and the outcome after treatment by posterior-only 2-level vertebral column resection (PVCR).

METHODS

Between 2011 and 2014, 6 patients were treated for kyphoscoliotic deformities with progressive rotational dislocation. In these 6 patients (2 males and 4 females), the diagnosis included 4 cases of congenital kyphosis and 2 cases of neurofibromatosis; the distribution of spine level was from T4 to T11; the kyphosis angle of the patients was 115° (range, 107-125°); the scoliosis angle was 97° (range, 80°-117°); follow-up ranged from 13 to 51 months (mean, 27 months). Four patients developed progressive onset of neurologic deficit. All patients underwent surgery by 2-level PVCR for decompression and correction of kyphoscoliosis.

RESULTS

Postoperatively, the patients all had different kyphosis correction rates, from 49% to 72% (mean, 63%) and scoliosis correction rates, from 57% to 78% (mean, 65%). All patients achieved successful spinal fusion with less than 3° of loss of correction at the latest follow-up evaluation. The 4 patients with incomplete neurologic deficits improved 1 or 2 American Spinal Injury Association scales at follow-up of at least 6 months.

CONCLUSIONS

Two-level PVCR is a safe and efficacious surgical option for the treatment of rotational dislocation in kyphoscoliosis and associated neurologic deficit.