Correction Of Cervical Kyphosis Research Articles

Finite element analysis of a new preoperative traction for cervical kyphosis: suspensory traction.

A finite element model of cervical kyphosis was established to analyze the stress of cervical spine under suspensory traction and to explore the mechanism and effect of it. A patient with typical cervical kyphosis (C2-C5) underwent CT scan imaging, and 3D slicer was used to reconstruct the C2 to T2 vertebral bodies. The reconstructed data was imported into Hypermesh 2020 and Abaqus 2017 for meshing and finite element analysis. The changes of the kyphotic angle and the von Mises stress on the annulus fibrosus of each intervertebral disc and ligaments were analyzed under suspensory traction conditions. With the increase of suspensory traction weight, the overall kyphosis of cervical spine showed a decreasing trend. The correction of kyphosis was mainly contributed by the change of kyphotic segments. The kyphotic angle of C2-C5 was corrected from 45° to 13° finally. In cervical intervertebral discs, the stress was concentrated to anterior and posterior part, except for C4-5. The stress of the anterior longitudinal ligament (ALL) decreased from the rostral to the caudal, and the high level von Mises stress of the kyphotic segments appeared at C2-C3, C3-C4, and C4-C5. The roles of the other ligaments were not obvious. The kyphotic angle was significantly reduced by the suspensory traction. Shear effect due to the high von Mises stress in the anterior and posterior parts of annulus fibrosus and the tension on the anterior longitudinal ligament play a role in the correction of cervical kyphosis.

Cervical kyphosis correction in Marfan syndrome: our experience and literature review.

Spinal deformities are common in Marfan syndrome (MFS). They usually involve the thoraco-lumbar spine but rarely involves the cervical spine. Kyphosis is the common spine deformity of the cervical spine and mandates surgical correction as they are at risk of neurological deterioration since they are refractory to conservative management. Few studies of surgical correction of spine deformity included cervical deformity. To analyze the challenges faced during surgery, clinical and radiological outcome, and complications following surgical correction for cervical kyphosis in Marfan syndrome. We identified that 5 patients with a diagnosis of MFS with cervical kyphosis who underwent fusion surgery between the years 2010 and 2022 were reviewed, retrospectively. We analyzed the demographic details, radiological parameters, operative variables (blood loss and nuances), perioperative complications, length of stay, clinical and radiological outcome, and complications following fusion surgery for cervical kyphosis in MFS. The mean age of patients was 16.6 ± 4.72years (range, 12-23years). The average kyphotic vertebra involved is 3 ± 0.7 bodies (range 2-4) with 2 patients with thoracic deformity. All patients underwent surgical deformity correction. All patients improved clinically with Nurick grade (pre vs. post: 3.4 vs. 2.2) and mJOA (pre vs. post: 8.2 vs. 12.6). There was significant deformity correction from 37.48° to 9.1°. Mean blood loss encountered was 900 ± 173.2ml. Perioperative complications: wound complication with CSF leak (1). Late complications: ventilator dependence (1) and junctional kyphosis (1). Mean length of hospital stay was 103 ± 178.9days. All patients were doing symptomatically better after mean follow-up of 58 ± 28.32months. One patient is bedridden and hospitalized. Cervical kyphosis is a rare spine deformity in patients with MFS, and they usually present with neurological deterioration mandating surgical correction. Multidisciplinary approach (pediatrics, genetics and cardiology) is required for systematic evaluation of these patients. They should be evaluated with necessary imaging to rule out associated spinal deformity (atlanto-axial subluxation, scoliosis, and intraspinal pathology like ductal ectasia). Our results suggest better surgical outcome in terms of low operative complications with neurologic improvement in MFS patients. These patients require regular follow-up to identify late complications (instrument failure, non-union, and pseudarthrosis).

Correction of pediatric cervical kyphosis with standalone posterior approach-a single-center experience of seven cases.

To study clinical and radiological outcomes of pediatric cervical kyphosis correction with a standaloneposterior cervical approach. Cervical spine kyphotic deformity in pediatric age group is a distinct entity and themanagement is challenging. Pediatric cervical kyphosis is less often encountered, and literature is sparse with onlyfew case series. Management algorithms are devised keeping the flexibility of the deformity at the core of decisionmaking. Circumferential fusion is mostly recommended for non-flexible (rigid) kyphosis. Authors present a single center retrospective analysis of cases of pediatric cervical kyphosis managed bya standalone posterior approach. Pre- and post-operative clinical and radiological parameters were recorded andanalyzed. Changes in neurological status, kyphosis correction and bony fusion were assessed. Surgical andimplant related complications were noted. Seven cases (6 male, 1 female) were included. Mean age was 13.9±2.9 years, ranging from 8-17 years.Etiology was traumatic in 2 cases, developmental in 2, and syndromic, Hirayama disease and post-laminectomy in1 case each. Mean kyphosis correction was 36.80±19.30 (87%±21%) with a mean pre-operative kyphosis angle of37.80±15.30 and mean immediate post-operative kyphosis angle of 3.70±8.70. Mean hospital stay duration was10±6 days. Median follow-up duration was 36 months. Myelopathy improved in 5 cases at last follow-up. Six casesdemonstrated bony fusion at a mean follow-up of 8.4±1.5 months. Significant immediate correction in pediatric cervical kyphosis may be achieved with a standaloneposterior approach with proper planning and technique in selected cases. Inserting pedicle screws at strategiclocations of implant construct offer better corrections and pull-out strength and maintain long-term stability resultingin higher arthrodesis rates. Larger studies with longer follow up are needed to further ascertain the role ofstandalone posterior cervical approaches in pediatric cervical kyphosis.

Patient-specific numerical investigation of the correction of cervical kyphotic deformity based on a retrospective clinical case

Little research has been reported on evaluating the safety of the fixation construct in cervical kyphosis correction. In this study, we proposed a principal-strain criterion to evaluate the safety of the fixation construct and validated the modeling method against a retrospective case of anterior cervical discectomy fusion (ACDF). From C2 to T2 vertebra bodies, fixation instruments were reconstructed and positioned as per postoperative computed tomography (CT) scans. Head weight (HW) and various moments estimated from isometric strength data were imposed onto the C2. The postoperative stability of non-surgical segments, deformations surrounding the screw trajectories, and contact slipping on zygapophysial joints were analyzed. The model was validated against the reality that the patient had a good fusion and deformity correction. The ACDF restricted the range of motions (ROMs) of cervical segments and lent stability to vertebra fusion, no failure was found in the finite element (FE) model of cervical vertebrae. The deformation surrounding the screw trajectories were concentrated to the lateral sides of trajectories, recommending that the shape of the anterior cervical plate conforming to the curvature of the vertebra and screws fully inserted into vertebrae reduced the deformation concentration around the screw trajectories.

Spinal screening, malignancy, medical therapy, and surgical correction of deformity in pediatric patients with neurofibromatosis type 1: a systematic review.

The objective of this systematic review was to synthesize evidence regarding spinal screening recommendations, types of spinal and thoracic neurofibromatosis type 1 (NF1) tumors, medical therapy for NF1-associated neoplasms, and treatment with magnetically controlled growing rods (MCGRs) or cervical kyphosis correction in pediatric patients with NF1. We queried PubMed, Embase, Cochrane Library, Web of Science, Scopus, Clinicaltrials.gov, and medRxiv for studies reporting spinal screening recommendations, prognosis, and medical therapy for NF1-associated spinal tumors and MCGR use or cervical kyphosis correction in pediatric NF1 patients, yielding 758 publications, 33 of which were included. There is no consensus on spinal screening interval. Computed tomography is recommended for postoperative monitoring. Patients with gangliomas and spinal neurofibromas had nearly complete symptom resolution after resection. Plexiform neurofibromas were most commonly treated with resection and laminectomy; some patients reported tumor enlargement after intervention. Malignant nerve sheath tumors have high rates of metastasis even after chemoradiation and resection. MEK-inhibitors produced limited regression in tumor size. Sirolimus and thalidomide reduced tumor size but caused more severe adverse effects than MEK-inhibitors. Improvements in major curves and T1-T12 height gain were reported after MCGR intervention. Anteroposterior arthrodesis produced the greatest correction of dystrophic cervical kyphosis. There may be value in establishing standardized spinal screening protocols for pediatric NF1 patients. Surgical correction of NF1-associated spinal deformity is effective, though current medical therapies for spinal tumors have limited success. Areas for further investigation include determining appropriate screening intervals, choice of medical therapy for spinal tumors, and long-term outcomes of MCGRs. Level of Evidence: IV.

Halo traction combined with posterior-only approach correction for cervical kyphosis with Neurofibromatosis-1: minimum 2\u2009years follow-up

BackgroundSurgical 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.MethodsTwenty-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.ResultsIn 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.ConclusionHalo 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.

Front-Back Cervical Deformity Correction by Anterior Cervical Discectomy and Fusion With Posterior Instrumentation: 2-Dimensional Operative Video.

Front-back procedures for cervical deformity permit the correction of cervical kyphosis in the setting of unfused facets. Here, we highlight the operative treatment of a 65-yr-old female entailing a 4-level anterior cervical discectomy and fusion (ACDF) at C3-C4, C4-C5, C5-C6, and C6-C7 with hyperlordotic interbody implants, supplemented by a posterior C2-T2 instrumented fusion. The patient initially presented with symptoms of treatment-refractory neck pain while neurologically intact on examination. Her imaging demonstrated significant cervical kyphosis measuring 46° as the Cobb angle between C2 and C7 without neural compression. The patient consented to the procedure and publication of their image. After 2 d of traction, the operation proceeded with the patient initially in a supine position with dissection medial to the sternocleidomastoid muscle down to the vertebral bodies. Discectomies were performed at each level followed by installation of the interbody implants. After closure of this access wound, the patient was turned to a prone position for the posterior element of the operation. The posterior bony elements were exposed and a C2-T2 instrumented fusion performed. Postoperative imaging demonstrated improvement of her sagittal cervical curvature and the patient described improvement in her neck pain.

The differential effect of cervical kyphosis correction surgery on global sagittal alignment and health-related quality of life according to head- and trunk-balanced subtype.

No reports have investigated how cervical reconstructive surgery affects global sagittal alignment (GSA), including the lower extremities, and health-related quality of life (HRQOL). The study was aimed at elucidating the effects of cervical reconstruction on GSA and HRQOL. Twenty-three patients who underwent reconstructive surgery for cervical kyphosis were divided into a head-balanced group (n = 13) and a trunk-balanced group (n = 10) according to the values of the C7 plumb line, T1 slope (T1S), and pelvic incidence minus lumbar lordosis (PI-LL). Head-balanced patients are those with a negative C7 sagittal vertical axis (SVA), a larger LL than PI, and a low T1S. Trunk-balanced patients are those with a positive SVAC7, a normal PI-LL, and a normal to high T1S. Various sagittal Cobb angles, SVA, and lower-extremity alignment parameters were measured before and after surgery using whole-body stereoradiography. Cervical malalignment was corrected to achieve cervical sagittal balance and occiput-trunk (OT) concordance (center of gravity [COG]-C7 SVA < 30 mm). Significant changes in the upper cervical spine and thoracolumbar spine were observed in the head-balanced group, but no significant change in lumbopelvic alignment was observed in the trunk-balanced group. Lower-extremity alignment did not change substantially in either group. HRQOL scores improved significantly after surgery in both groups. SVACOG-C7 and SVAC2-7 were negatively and positively correlated with the 36-Item Short-Form Health Survey physical component score and Neck Disability Index, respectively. The visual analog scale for back pain, Oswestry Disability Index, and PI-LL mismatch improved significantly in the head-balanced group after cervical reconstruction surgery. Patients with cervical kyphosis exhibited compensatory changes in the upper cervical spine and thoracolumbar spine, instead of in the lower extremities. These compensatory mechanisms resolved reciprocally in a different fashion in the head- and trunk-balanced groups. HRQOL scores improved significantly with GSA restoration and OT concordance following cervical reconstruction.

Surgical Impact on Global Sagittal Alignment and Health-Related Quality of Life Following Cervical Kyphosis Correction Surgery: Systematic Review.

When spinal imbalance occurs, the human body reacts through various compensatory mechanisms to maintain the head over the pelvis and to retain a horizontal gaze. These compensations occur through mobile spine segments as well as pelvic tilt and lower extremities. The purpose of this review was to understand the surgical impact on global sagittal alignment and health-related quality of life (HRQoL) following cervical kyphosis correction surgery. The cervical kyphosis correction surgery induces reciprocal changes in craniocervical and thoracolumbar alignment. Successful cervical deformity correction needs to focus not only on restoring proper cervical lordosis, but also on achieving global balance of the cervical spine with other parts of the spine. The goal of the surgery is to achieve occiputtrunk (OT) concordance (the center of gravity-C7 sagittal vertical axis < 30 mm) and cervical sagittal balance. Once OT-concordance is achieved, subsequent thoracolumbar alignment changes occur as needed to harmonize global spinal alignment. Reciprocal changes after surgery exhibit different patterns depending on whether patients have compensation ability in their thoracolumbar spine or not. C2–7 sagittal vertical axis and sagittal morphotype of the cervical kyphosis are correlated with HRQoL. Changes in cervical lordosis minus T1 slope correlate to HRQoL improvements.

Modified C7 pedicle subtraction osteotomy for the correction of cervicothoracic kyphosis

BackgroundOsteotomies in the cervical spine are technically challenging. The purpose of this study was to evaluate the feasibility of the modified pedicle subtraction osteotomy (PSO) technique at C7 to be used for the treatment of cervicothoracic kyphosis secondary to ankylosing spondylitis.MethodsA total of 120 cervical spine computed tomography (CT) scans (of 82 male and 38 female patients) were evaluated. The scans were taken parallel to the middle sagittal plane and the sagittal plane intersecting the pedicles. Simulated osteotomy was performed by setting the apex of the wedge osteotomy at different points, and morphologic measurements were obtained. Seven patients with cervicothoracic kyphosis who underwent a modified PSO at C7 between May 2009 and June 2015 were retrospectively evaluated. The mean follow up was 32.9 months (range 21–54 months). Preoperative and postoperative chin-brow vertical angle (CBVA), sagittal vertical axis (SVA) and sagittal Cobb angle of the cervical region were reviewed. The outcomes were analyzed through various measures, which included the 36-Item Short Form Health Survey (SF-36) and a visual analog scale for neck pain.ResultsIn this morphometric study, a modified PSO was performed on 87 patients (59 male and 28 female) with a reasonable ratio of 72.5%. In the case series, radiographic parameters and health-related quality-of-life measures were found to show significant postoperative improvement in all patients. No major complications occurred, and no implant failures were noted until the latest follow up.ConclusionsThe modified PSO is a safe and valid alternative to the classic PSO, allowing for excellent correction of cervical kyphosis and improvement in health-related quality-of-life measures.

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

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. 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. 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. 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.

Cervical Spine Deformity Correction Techniques.

Cervical kyphotic deformity can be a debilitating condition with symptoms ranging from mechanical neck pain, radiculopathy, and myelopathy to impaired swallowing and horizontal gaze. Surgical correction of cervical kyphosis has the potential to halt progression of neurological and clinical deterioration and even restore function. There are various operative approaches and deformity correction techniques. Choosing the optimal strategy is predicated on a fundamental understanding of spine biomechanics. Preoperative characterization of cervical malalignment, assessment of deformity rigidity, and defining postoperative clinical and radiographic objectives are paramount to formulating a surgical plan that balances clinical benefit with morbidity. This review of cervical deformity treatment provides an overview of the biomechanics of cervical kyphosis, radiographic classification, algorithm-based management, surgical techniques, and current surgical outcome studies.

Total uncinectomy of the cervical spine with an osteotome: technical note and intraoperative video.

Total uncinate process resection or uncinectomy is often required in the setting of severe foraminal stenosis or cervical kyphosis correction. The proximity of the uncus to the vertebral artery, nerve root, and spinal cord makes this a challenging undertaking. Use of a high-speed burr or ultrasonic bone dissector can be associated with direct injury to the vertebral artery and thermal injury to the surrounding structures. The use of an osteotome is a safe and efficient method of uncinectomy. Here the authors describe their technique, which is illustrated with an intraoperative video.

Surgery treatment of neurofibromatosis associated severe cervical kyphotic deformity: mid- and long-term follow-up and efficacy analysis

Objective: To investigate the surgical strategy and mid-and long-term outcomes of neurofibromatosis associated cervical kyphotic deformity. Methods: Thirteen patients with neurofibromatosis associated cervical kyphotic deformity operated in Shanghai Changzheng Hospital from January 1998 to December 2015 were analyzed retrospectively. There were 7 males and 6 females in this group, aged from 12 to 61 years, with an average age of (28±15) years. Eight patients were treated with anterior surgery (Group A) and 5 patients were treated with combined anterior and posterior surgery (Group A+P). Cobb angle correction of cervical kyphosis and improvement of clinical symptoms were followed up. Clinical efficacy between the two groups was compared and analyzed. Chi-square test, Fisher exact test and independent sample t test were used for comparative analysis between the two groups. Results: All patients were operated successfully and finished follow up. The follow-up period was from 42 to 128 months ((80±22) months). After the surgery, neurological symptoms and pain were significantly improved in all patients. Compared with preoperative values, Japanese Orthopedic Association (JOA) score and visual analogue scale (VAS) score for pain at the last follow-up were significantly improved (t=7.63, -5.19, 8.63, -4.75, all P<0.01). Cervical kyphosis was significantly improved in all patients after surgery. In group A, the Cobb angle was improved from 64°±24° preoperatively to 12°±11° at the last follow-up, and the average correction rate of Cobb angle was 82.6%. In group A+P, the Cobb angle was improved from 55°±10° preoperatively to 7°±9° at the last follow-up, and the average correction rate of Cobb angle was 88.3%. The operation time, intraoperative blood loss and length of stay in group A were all significantly lower than those in group A+P (t=-6.32, -11.92, -6.52, all P<0.01). At the last follow-up, there was no significant difference in Cobb angle, JOA score and VAS score between the two groups (t=0.89, 0.94, 1.02, all P>0.05). Conclusions: Mid-and long-term results of anterior and combined anterior and posterior surgery for neurofibromatosis associated severe cervical kyphosis are satisfactory. Moderate correction strategy for cervical kyphosis is safe and effective. The incidence of complications of nerve injury can be reduced.

Long-Term Changes in Vertebral Morphology After Cervical Spinal Fusion in Adolescent Pediatric Patients: Retrospective Case Series with up to a Minimum 12 Years of Follow-up

The mechanical alteration in the adolescent/pediatric cervical spine after spinal fusion remains unknown. The purpose of this study was to investigate morphologic changes in the cervical spine in adolescent/pediatric patients who underwent spinal fusion. Ten adolescent/pediatric patients (9-18 years) who underwent cervical spinal fusion were included. The anteroposterior diameter (AP-D) of the vertebral body was evaluated using lateral radiographs. The AP-D ratio was defined as the ratio of the AP-D at final follow-up to the postoperative value. The kyphosis angles at the fused level and cervical spine (C2-C7) also were measured. The mean follow-up period was 20.0 years (range, 12-40 years). The AP-D was reduced in 4 patients and increased or remained unchanged in 6 patients. The AP-D reduction was usually seen at the middle of the fused levels and was remarkable in patients who underwent kyphosis correction using posterior instrumentation combined with anterior fusion. The AP-D ratio was significantly correlated to segments of anterior fusion (P= 0.029) and the kyphosis angle of the fused levels (P= 0.016). Cervical kyphosis correction using posterior instrumentation combined with endplate destruction by anterior bone grafting is a risk factor for atrophic morphologic changes in the vertebral body in adolescent/pediatric patients. Endplate destruction and instrumentation-induced stress shielding could alter bone remodeling.

Cervical Deformity Patients Have Baseline Swallowing Dysfunction but Surgery Does Not Increase Dysphagia at 3 Months: Results From a Prospective Cohort Study.

Study Design:Prospective cohort study.Objectives:Most studies of dysphagia in the cervical spine have focused on a degenerative patient population; the rate of dysphagia following surgery for cervical deformity (CD) is unknown. This study aims to investigate if surgery for cervical deformity results in postoperative dysphagia.Methods:Patients with CD undergoing surgery from 2013 to 2015 were prospectively enrolled to evaluate dysphagia. Demographic, operative, and radiographic variables were analyzed. The Quality of Life in Swallowing Disorders (SWAL-QoL) was used to measure dysphagia. Paired t test, independent t tests, and bivariate Pearson correlations were performed.Results:A total of 88 CD patients, aged 61.52 ± 10.52 years, were enrolled. All patients (100%) had 3-month SWAL-QoL for analysis. The baseline preoperative SWAL-QoL was 78.35. This is roughly the same level of dysphagia as an anterior cervical discectomy patient that is 3 weeks removed from surgery. Increasing body mass index (BMI) was correlated with decreased SWAL-QoL score (r = −0.30, P = .001). Age, gender, smoking, and Charlson Comorbidity Index (CCI) showed no significant correlations with preoperative SWAL-QoL. Patients with prior cervical surgery had a lower preoperative SWAL-QoL (P = .04). While 11 patients had acute postoperative dysphagia, CD surgery did not result in lower SWAL-QoL at 3 months (77.26 vs 78.35, P = .53). Surgical variables, including estimated blood loss (EBL), anterior or posterior fusion levels, steroid use, preoperative traction, staged surgery, surgical approach, anterior corpectomy, posterior osteotomy, and UIV (upper instrumented vertebrae) location, showed no impact on postoperative SWAL-QoL. Correction of cervical kyphosis was not correlated to 3-month SWAL-QoL scores or the change in SWAL-QoL scores.Conclusions:While patients undergoing surgery for cervical deformity had swallowing dysfunction at baseline, we did not observe a significant decline in SWAL-QoL scores at 3 months. Patients with prior cervical surgery and higher BMI had a lower baseline SWAL-QoL. There were no surgical or radiographic variables correlated to a change in SWAL-QOL score.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P109. Effect of cervical deformity correction on stenosis, spinal canal and cord compression utilizing magnetic resonance and computed tomography imaging modalities

BACKGROUND CONTEXT Cervical deformity (CD), often degenerative in etiology, is typically accompanied by the onset of symptomatic spinal stenosis. It is hypothesized that causation of spinal canal and cord compressive forces is multifactorial, with reduction of compressive forces being a key driver of symptom alleviation. PURPOSE To quantify and assess the relationship between postoperative changes to sagittal alignment, canal or cord decompression, and symptom alleviation. STUDY DESIGN/SETTING Retrospective review of a prospective CD database. PATIENT SAMPLE Twenty-seven CD patients. OUTCOME MEASURES Stenotic Levels, Pavlov Ratio, Spinal Canal Cross-Sectional Area, Spinal Cord Cross-Sectional Area, mJOA scores, NSR Neck Pain scores. METHODS ConsecutiveCD patients (C2–C7 Cobb>10°, CL>10°, cSVA>4 cm, or CBVA>25°) undergoing multilevel fusion. Those with pre-operative magnetic resonance imagings (MRIs) and 1-year post-operative cervical MRI or CT scans were assessed for spinal canal and cord cross-sectional area, using dedicated imaging software at each interspace and body from C2–C7, and the apex of deformity[apex]. Stenotic vertebral levels were measured using Pavlov's method from C2 to C7: a ratio of canal to vertebral body RESULTS A total of 27 patients were included (61±10 years, 64.2%F, BMI: 29.6±8.0, CCI: 0.81±1.1). BL radiographic assessment: TS-CL: 34.0±17.2; Cervical Lordosis: −1.6±15.7; cSVA: 36.3±18.5; PI-LL: 0.12±19.3; Pelvic Tilt: 20.1±11.6; SVA: 0.94±71.6. Ames classification deformity descriptors: C: 57.7%, CT: 30.8%, T: 7.7%, S: 3.8%. Surgical approach included 7.4% anterior, 51.9% posterior, 40.7% combined; 23(79%) patients had decompression procedures, all patients had an osteotomy, and mean fusion length was 8.6±4.2 levels. Following surgical intervention, mean canal cross-sectional area (267.5 mm2 vs. 320.5 mm2, p=.025), apex canal cross-sectional area (240 mm2 vs. 301.3 mm2, p=.039), and apex cord cross-sectional area (60.6 mm2 vs. 70.1 mm2, p=.019) all increased (regardless of decompression procedure status). Decreased stenotic levels (4.11vs. 2.97, p=.003) and improved apex pavlov ratios (0.76vs. 0.91, p=.032) were also observed. Cervical kyphosis correction correlated with Δ in stenotic levels (rs: 0.664, p=.001), Δ in mean C2–C7 pavlov ratio (rs: 0.601, p=.004), and Δ in apex canal area (rs: 0.562, p=.024). TS-CL correction correlated with Δ in stenotic levels (rs: 0.751, p CONCLUSIONS Sagittal realignment was associated with reduction of symptomatic stenosis and cord compressive forces, regardless of decompression status. Stenotic level reduction was associated with improved mJOA scores, while alleviation of dynamic radial compressive forces at the apex of deformity significantly reduced patient neck pain.

Review of surgical correction of cervical kyphosis

Kyphotic deformity of the subaxial cervical spine can be debilitating to the patient, as well as challenging to the spine surgeon. Cervical kyphotic deformity is frequently progressive and can result in neurologic decline that mirrors the increase in deformity thus requiring surgical correction to alter the natural progression of the deformity. We review common etiologies, clinical and diagnostic workup, as well as pearls and pitfalls of each of the approaches to the cervical spine. Indications and contraindications for anterior, posterior, and combined approach are addressed.

Effect of correction surgery for cervical kyphosis on compensatory mechanisms in overall spinopelvic sagittal alignment.

Progression of kyphotic deformity at the middle/lower cervical spine can cause difficulty with horizontal gaze, so compensation at other spinopelvic parts may occur. However, the precise mechanism remains unclear. The present study investigated the effect of correction surgery for cervical kyphosis on the compensatory mechanisms in overall spinopelvic sagittal alignment. Forty-one patients, comprising 23 males and 18 females (mean age 67years), underwent correction surgery for cervical kyphosis using the posterior screw-rod system. Spinopelvic lateral radiographs in the standing position were taken before and after surgery. C0-1 angle, C1-2 angle, clivo-axial angle (CAA), C2-7 angle, thoracic kyphosis, lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope were measured. Correlations between C2-7 angle and these parameters before surgery, and correlations between the correction angle of cervical kyphosis and postoperative changes of these parameters were evaluated. Negative correlations were found between the C2-7 angle and CAA (R=-0.640, p<0.01), and C2-7 angle and C0-1 angle (R=-0.762, p<0.001) before surgery. Negative correlations were found between the correction angle of C2-7 and change of CAA (R=-0.718, p<0.001), and between the correction angle of C2-7 and change of C0-1 angle (R=-0.672, p<0.01) after surgery. The present study demonstrated that C0-1 angle and CAA are more important in the compensatory mechanism for kyphotic deformity at the middle/lower cervical spine compared to downward parameters. That is, to maintain horizontal gaze, lordosis increases at the cranio-cervical junction with greater kyphosis at the middle/lower cervical spine. Correction of cervical kyphosis in the middle/lower cervical spine resulted in normalization of the C0-1 angle and CAA because the compensatory mechanism at the cranio-cervical junction for obtaining horizontal gaze was no longer necessary after surgical intervention.

Outcomes of Spinal Fusion for Cervical Kyphosis in Children with Neurofibromatosis.

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