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

Basilar invagination and atlantoaxial dislocation as a complication of severe dystrophic cervical kyphosis correction in neurofibromatosis type 1: Report of a rare case and review of literature

INTRODUCTION AND IMPORTANCE

Neurofibromatosis type 1 (NF1) affects the musculoskeletal system as well as the cervical spine. It is associated with severe, progressive cervical kyphosis. Surgical intervention is the treatment of choice to avoid neurological impairment and malalignment.

CASE PRESENTATION

We herein report an 11-year-old NF-1 patient with severe cervical kyphosis and intact neurological status. We applied five days of cervical traction followed by surgery utilizing the combined cervical approach (posterior release, anterior corpectomy and reconstruction, and posterior cervicothoracic instrumentation). In one-year follow-up, atlantoaxial dislocation (AAD) and basilar invagination (BI) were detected in neuroimagings. The complication was corrected by adding C1 to the previous construct via unilateral C1 lateral mass screw, contralateral C1 sublaminar hook, unilateral C3 and contralateral C4 sublaminar hook insertion, fixed with contoured rods medial to previous rods. This led to the correction of the AAD and the BI and the patients remained neurologically intact.

CLINICAL DISCUSSION

Severe cervical kyphosis in the setting of NF-1 is progressive and carries a considerable risk of neurologic compromise. Surgical intervention is thus necessary.

CONCLUSION

The combined approach with complete spinal column reconstruction is the surgical approach of choice. However, complete curve correction to near-normal lordosis carries the risk of proximal junctional failure (PJF).

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.

Cervicothoracic dislocation due to congenital and bone-dysplasia-related vertebral malformations

PURPOSE

To evaluate the approaches to treatment of congenital and bone-dysplasia-related pediatric cervicothoracic dislocations and define the optimal treatment method.

METHODS

The publications available in PubMed and Google Scholar data bases were selected following such criteria as the disease in question, pediatric age, the treatment description, and follow-up results. The paper also includes the descriptions of our own six cases of the cervicothoracic dislocations detected in children with different vertebral malformations.

RESULTS

Only eight patients meeting the abovementioned selection criteria were found in the publications: three of them had the Klippel-Feil syndrome (KFS), two had one-level vertebral anomaly, one had neurofibromatosis (NF type 1), one had the Larsen syndrome, and one had a variation of VACTERL association. Their treatment was long term, multi stage, and complicated. Among six our own cases, four patients also had KFS, one had a variation of VACTERL association, and one had NF type 1. All the patients suffered from preoperative neurological disorders. Posterior instrumental fixation with posterior vertebral body resection was performed in four cases and one patient underwent a combined surgery. The parents of one of the patients refused the operation, so he was observed while receiving bracing treatment. Since the treatment was long term and complicated by reoperations, the average follow-up period comprised 5 years.

CONCLUSION

Congenital cervicothoracic dislocations are an extremely rare pathology that manifests itself in early age and requires an early surgical treatment. Failure to provide the treatment leads to the patient's disability. The surgical tactics for such patients is determined individually, but the published data and our own experience demonstrate that early multi-stage combined treatment has been the best option available so far. The cervicothoracic dislocations due to NF 1 manifest later and have a more favorable forecast.