Anterior Fusion and Posterior Correction of Severe Cervical Kyphosis Using Pedicle Screw Fixation in a Patient with Neurofibromatosis

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.

Uninstrumented fusion in cervical kyphosis due to neurofibromatosis type I: report of two paediatric cases

PURPOSE

Severe cervical kyphosis (CK) in neurofibromatosis type 1 (NF-1) is associated with a high risk for progression and neurologic impairment in children. We present our surgical technique and mid-term outcomes of uninstrumented anterior tibial strut grafting for severe CK secondary to NF-1.

METHODS

Case report. The Consensus-based Clinical Case Reporting Guideline Development (CARE) guidelines were followed.

RESULTS

Two paediatric patients (8- and 3-year-old) presented with severe CK secondary to NF-1. A halo body jacket (HV) allowed the progressive distraction of the cervical spine, avoiding neurological compromise and deformity progression. Circumferential fusion was obtained with anterior tibial strut autograft and posterior onlay bone graft. Cervical spine fusion was successfully maintained at a minimum 4-year follow-up in both patients.

CONCLUSION

In children with severe CK secondary to NF-1, cervical distraction and immobilisation with a HV followed by uninstrumented anterior tibial strut grafting and posterior bone grafting, provided spinal fusion and stability without increasing the risk of neurological injury and donor site morbidity. The reported surgical technique appears to be a valuable tool in the armamentarium of the spinal surgeon.

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.

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.

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.

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.

A Radiographic Analysis of Cervical Sagittal Alignment in Adolescent Idiopathic Cervical Kyphosis

OBJECTIVE

The aim of this study was to analyze the radiologic features of adolescent idiopathic cervical kyphosis.

SUMMARY OF BACKGROUND DATA

There are few previous reports about radiographic analysis of cervical sagittal alignment of adolescent idiopathic cervical kyphosis. A new method was proposed in this article to evaluate the severity of cervical kyphosis.

PATIENTS AND METHODS

A total of 41 adolescent patients with cervical kyphosis were reviewed. Several angles were measured from the radiographs utilizing the 2-line Cobb method and Harrison posterior tangent method. Ishihara's Curvature Index (CI), Kyphosis Index (KI), kyphosis levels, and the apex of the kyphosis were also measured.

RESULTS

The results showed that the apex of the kyphosis is located at the posterior-superior edge of C4 (70.7%) and C5 (29.3%). C2-C7 angles ranged from 4.7 to 71.3 degrees (36.2±13.6 degrees) and from 9.8 to 83.1 degrees (36.4±15.1 degrees) in the above 2 methods, respectively. Local angles of kyphotic area ranged from 21.8 to 96.3 degrees (50.5±23.7 degrees) in 2-line Cobb method and from 19.8 to 105.6 degrees (52.0±19.5 degrees) in Harrison posterior tangent method. CI and KI ranged from 8.6 to 79.8 (36.8±16.7) and 15.2 to 141.9 (50.6±23.7), respectively. Statistical analysis showed that there was significant positive correlation between KI and kyphosis angle.

CONCLUSIONS

In adolescent idiopathic cervical kyphosis, the alteration of the sagittal profile only occurs on partial cervical alignment rather than the whole cervical spine. The apex of the kyphosis locates at posterior-superior edge of the vertebrae. It seems that KI can accurately depict the severity of cervical kyphosis.

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.

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

Severe cervical kyphosis requiring surgical treatment is rare in patients with neurofibromatosis Type 1 (NF1). When it occurs, however, dystrophic changes in the vertebrae make surgical correction and fusion of the deformity extremely difficult.

The authors report on 3 cases of severe cervical kyphosis associated with NF1 that were successfully treated with combined anterior and posterior correction and fusion. All patients underwent halo-gravity traction for approximately 1 month prior to surgery to correct the deformity gradually. Posterior correction and fusion were performed with segmental spinal instrumentation consisting of lateral mass screws, lamina screws, pedicle screws, and polyethylene tape for sublaminar wiring. Anterior spinal fusion was performed using a fibula strut to induce solid bone fusion. All patients used a halo vest for postoperative external fixation.

Preoperative CT scans showed dystrophic cervical spine changes, and MR images demonstrated extensive neurofibromas outside the cervical spine in all 3 patients. The preoperative kyphotic angles were as follows: Case 1, 140°; Case 2, 81°; and Case 3, 72°; after halo-gravity traction, the kyphosis angles improved to 50°, 55°, and 51°, respectively; and after surgery, they were 50°, 15°, and 27°, respectively. Solid bone union was observed in all patients at the latest follow-up. All three patients experienced postoperative complications consisting of superficial infection, severe pneumonia, and partial dislocation of the distal fibula graft after removing the halo vest, in one patient each.

Although dystrophic cervical vertebral changes in these patients with NF1 complicated the correction of severe cervical kyphosis, the use of preoperative halo-gravity traction, a combination of spinal instrumentations, an anterior strut bone graft, and postoperative halo-vest fixation made it possible to correct the kyphosis, maintain the correction, and achieve solid bone fusion.

Cervical neurofibromatosis with tetraplegia: management by cervical suspensory traction

STUDY DESIGN

A case report.

OBJECTIVE

To describe a new method called "cervical suspensory traction" and to report its effect in the treatment of severe cervical kyphotic deformity with neurofibromatosis-1 (NF-1) in a teenager.

SUMMARY OF BACKGROUND DATA

Cervical kyphotic deformity exceeding 100° due to NF-1 is a challenging surgical problem. Surgery alone may result in poor corrective efficiency, too long range of fusion, sacrificing more mobile segments.

METHODS

An 18-year-old teenager with NF-1 presented with tetraplegia. Radiographs of the cervical spine revealed that kyphotic deformity of C3-C6 was 125°. Spinal release surgery was undertaken in advance, followed by cervical suspensory traction and subsequent posterior instrumentation and fusion surgery.

RESULTS

During a 4-year follow-up, the patient made a full neurological recovery. Cervical curve of C3-C6 was improved with a residual kyphosis of 30°. Stable bone fusion was obtained in the lower cervical spine. No complication had occurred.

CONCLUSION

Cervical suspensory traction is a viable and safe adjunct technique for applying gradual and sustained effort to maximize postoperative correction in the treatment of NF-1 patients with severely rigid and large curves. This report should contribute to expanding the alternative method for the staged treatment strategy to complex abnormalities.

Surgical management of cervical spine manifestations of neurofibromatosis Type 1: long-term clinical and radiological follow-up in 22 cases

Object

Patients with neurofibromatosis Type 1 (NF-1) at the cervical spine present significant surgical challenges due to neural compression, multiplicity of tumors, and complex spinal deformities. Iatrogenic instability following resection of tumors is underappreciated in the literature. The focus of this study was to understand the indications for stabilization in this specific group of patients.

Methods

The authors performed a retrospective review of 20 cases involving NF-1 patients with symptomatic cervical spine neurofibromas who underwent surgical decompression and tumor resection, with or without instrumentation, between 1991 and 2008. They also included 2 additional cases involving patients treated before 1991. Imaging findings and data pertaining to clinical presentation, intraoperative management, and postoperative assessment were compiled to clarify the indications for stabilization. An ordinal pain scale based on patient self-assessment was used. Neurological function was evaluated using American Spinal Injury Association Impairment Scale scores.

Results

The patient group comprised 13 men and 9 women. Their median age at presentation was 42.5 years; their median age at initial diagnosis of NF-1 was 30 years (range 8–74 years). The median duration of follow-up (since presentation) was 7 years (range 1–32 years). Progressive myelopathy was the main presenting symptom. Spinal cord compression was identified in 13 patients on presentation. Complete removal of the symptomatic tumors was performed in 11 patients. Ten patients underwent instrumented fusion during their first surgery. Six of these 10 required a second surgery—with fixation in 4 cases and without in 2. Of the 12 patients who did not receive instrumented fusion in their first surgery, 8 required a second surgery—with fixation in 5 cases and without in 3. Neurological deterioration due to progressive deformity was the indication for the second surgery in 3 of the 5 patients who required instrumented fusion only in their second surgery; the other 2 patients presented with neurological deterioration secondary to tumor progression. Four patients needed a third operation and instrumented fusion: 3 for deformity-related deficit and 1 for tumor progression. Based on the latest follow-up, 21 patients were stable clinically and radiologically, and 1 patient had died.

Conclusions

This specific group of patients represents a significant surgical challenge. In this retrospective analysis, emphasis is placed on early stabilization of the cervical spine to prevent late deformity as part of the comprehensive management of patients with NF-1.

Surgical treatment of severe cervical dystrophic kyphosis due to neurofibromatosis Type 1: a review of 8 cases

Object

The goal in this study was to retrospectively investigate the clinical efficacy of surgical treatment for cervical dystrophic kyphotic deformity due to neurofibromatosis Type 1.

Methods

Between January 1998 and July 2008, 8 patients with cervical dystrophic kyphotic deformity due to neurofibromatosis Type 1 (mean Cobb angle of 58.5°) were surgically treated in the authors' department. The mean age at surgery was 19 years (range 12–38 years). Among these patients, 1 with a Cobb angle of 52° and good flexibility underwent single anterior correction, whereas the other 7 patients with severe deformity and poor flexibility received combined anterior and posterior cervical osteotomy. Motor-evoked potential studies were used intraoperatively for spinal cord monitoring. Radiographic assessment and Japanese Orthopaedic Association scoring were used to evaluate the clinical outcome.

Results

No severe neurological complications were noted. Two patients complained of persistent neck and shoulder pain after combined anterior and posterior correction, which alleviated after conservative treatment half a year later. All patients were followed up for a mean of 21.1 months (range 6–36 months). All patients had a solid bone fusion at the latest follow-up, with Japanese Orthopaedic Association scoring improving from 11.5 preoperatively to 14.1 postoperatively (p < 0.01) at the final follow-up. The kyphotic deformities improved significantly, with average Cobb angles of 2.5° postoperatively and 4.1° at final follow-up.

Conclusions

The deformity of neurofibromatosis with cervical kyphosis is severe, and surgery carries a high risk of failure. Although premature fusion may be performed, the deformity may still progress, and this situation may lead to failure of surgery. The successful management of this disease requires early recognition and a more aggressive and reliable intervention to prevent disastrous worsening of the deformity. Meticulous preoperative evaluation, appropriate surgical strategy, and skilled technique were essential for successful surgical treatment and good clinical results.

Research update and recent developments in the management of scoliosis in neurofibromatosis type 1

Neurofibromatosis type 1 (NF-1) is an autosomal dominant hereditary disease characterized by an abnormal proliferation of cells from the neural crest. Neurofibromatosis type 1 is often associated with orthopedic disorders, especially scoliosis, which is the most common skeletal manifestation of NF-1. The effects of treatment of scoliosis in NF-1 are less satisfactory than other scoliotic types due to the particular pathogenesis and clinical characteristics. Early diagnosis and treatment may be the best way to improve outcomes. This article summarizes the recent genetic and clinical developments of scoliosis in NF-1.

Simulated surgery for a patient with neurofibromatosis type-1 who had severe cervicothoracic kyphoscoliosis and an anomalous vertebral artery

STUDY DESIGN

Case report.

OBJECTIVE

To describe the usefulness of simulated surgery for evaluation of a patient with neurofibromatosis type-1 (NF-1) who had severe cervicothoracic kyphoscoliosis and an anomalous vertebral artery (VA).

SUMMARY OF BACKGROUND DATA

Several surgical procedures have been used in the treatment of cervicothoracic kyphoscoliosis associated with myelopathy in patients with NF-1. However, to our knowledge, there has been no report that describes a surgical procedure for NF-1 patients with anomalous VA at the cervical spine.

METHODS

A 45-year-old man with NF-1 developed cervical myelopathy. Preoperative examinations revealed severe cervicothoracic kyphoscoliosis, dystrophic changes of the cervical vertebrae, and the anomalous course of a VA and VA aneurysms. To assist in the preoperative planning and intraoperative navigation, we created 3-dimensional (3D) full-scale models of the patient's spine. Using a model, we performed a simulation of the planned surgery for spinal cord decompression with spinal fusion through both anterior and posterior approaches.

RESULTS

Through the simulation, we could evaluate the risk of VA injury at the process of corpectomy, and altered the surgical procedure for the spinal cord decompression with spinal fusion from a posterior approach and a bone graft alone from an anterior approach. We accomplished the surgery successfully without any neurovascular complications. After surgery, the patient experienced relief from myelopathy.

CONCLUSION

Preoperative surgical simulation using a 3D full-scale model was useful for improving the accuracy and safety of the surgery for cervicothoracic kyphoscoliosis with NF-1.

Scoliosis associated with neurofibromatosis

Neurofibromatosis type 1 (NF-1) is a multisystemic disease. It may manifest as abnormalities of the nervous tissue, bones, soft tissue, and skin. The manifestations of NF-1 vary from person to person and range from subclinical to severe. Individuals who carry the gene eventually exhibit some clinical feature of the disease. The penetrance for NF-1 nears 100% during adulthood. Skeletal abnormalities are common in NF-1, with most patients presenting with some type of bony dysplasia. The orthopedic complications usually appear early. They include spinal deformities, such as scoliosis or kyphosis, congenital tibial dysplasia with bowing and pseudarthrosis of the tibia, forearm, other bones, as well as overgrowth phenomenon of an extremity, and soft tissue tumors.

Complex Deformities of the Cervical Spine

Cervical deformities arise from a multitude of causes, including genetic, congenital, inflammatory, degenerative, and iatrogenic etiologies. They often require surgical intervention for treatment of pain, progressive structural decompensation, and neurologic deterioration. Although congenital and hereditary causes of cervical deformity require specialized attention to particular clinical features and operative considerations, postsurgical (iatrogenic) cervical deformity after surgery is the most common single cause. Appropriate treatment involves careful selection of conservative and aggressive measures and familiarity with advanced surgical techniques that allow for the safe correction of these challenging deformities. Flexible deformities can be managed with single-staged procedures, whereas fixed deformities require two-staged or even three-staged procedures. Staged surgery for fixed cervical deformities can achieve up to 28 degrees of angular correction and 31% translational correction.

The clinical risk of vertebral artery injury from cervical pedicle screws inserted in degenerative vertebrae

STUDY DESIGN

Postoperative outcomes of cervical pedicle screw (CPS) placement were evaluated. The screws were inserted in degenerative vertebrae using anatomic landmarks.

OBJECTIVE

To evaluate the risks of this procedure caused by misplacements and subsequent complications.

SUMMARY OF BACKGROUND DATA

The CPS gives superior vertebral fixation but risks causing vertebral artery and spinal cord injury. However, few clinical reports have been published concerning CPS misplacement and subsequent complications. Therefore, the risk of this procedure is still unclear.

METHODS

There were 18 consecutive patients, who submitted to CPS fixation of degenerative vertebrae C2-C6, evaluated using computerized tomography (CT). In 5 of 9 patients in whom the screw critically violated the transverse foramen, viability of the vertebral artery was evaluated using multi-detector row CT angiography.

RESULTS

There were no intraoperative vertebral artery or spinal cord injuries and no serious postoperative complications. A total of 86 screws were inserted, and 25 (29%) breached the pedicle cortex. Of them, 84% deviated laterally and violated the transverse foramen. There were 13 screws (15%) that deviated more than 2 mm. However, multi-detector row CT angiography showed the continuity of the vertebral artery in all cases.

CONCLUSIONS

The deviation rate of CPS placement using anatomic landmarks was higher than anticipated, although no serious complications were encountered. Refinement of the technique (e.g., using a computer-assisted navigation system) is strongly recommended.

Spinal reconstruction using a cervical pedicle screw system

Although the cervical pedicle screw system is considered the most effective instrumentation for posterior cervical spine surgery, reports on clinical application are limited because of the unresolved and inherent risk of neurovascular complications. The purpose of this study is to retrospectively evaluate the accuracy of placement and clinical effectiveness of the cervical pedicle screw. The cases of 26 patients were investigated. The average followup was 20 months. All but one patient had simultaneous decompression and fusion of various extent. In these cases, screw placement, alignment of the fused segment, fusion rate, neurologic improvement, and complications were assessed. Using an image intensifier, 134 screws were inserted. Five screws (3.7%) completely perforated and 10 (7.4%) partially perforated. The complete perforations occurred in the first 10 patients. Except for two patients with metastasis, bony union was obtained in all patients without loss of correction. Neurologic impairment also was improved in all patients, and no complications associated with the cervical pedicle screw were seen. Clinical results of the cervical pedicle screw system were excellent with few complications. However, there is the possibility of screw perforation, which could cause neurovascular complications. Increased accuracy of screw insertion is needed to make this instrumentation safer.