Cervical Spine Deformity-Part 2: Management Algorithm and Anterior Techniques

Does Ending a Posterior Construct Proximally at C2 Versus C3 Impact Patient Reported Outcomes in Degenerative Cervical Myelopathy Patients up to 24 months After the Surgery?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The primary objective was to evaluate the impact of the upper instrumented level (UIV) being at C2 vs C3 in posterior cervical construct on patient reported outcomes (PROs) up to 24 months after surgery for cervical degenerative myelopathy (DCM). Secondary objectives were to compare operative time, intra-operative blood loss (IOBL), length of stay (LOS), adverse events (AEs) and re-operation.

METHODS

Patients who underwent a posterior cervical instrumented fusion (3 and + levels) with a C2 or C3 UIV, with 24 months follow-up were analyzed. PROs (NDI, EQ5D, SF-12 PCS/MCS, NRS arm/neck pain) were compared using ANCOVA. Operative duration, IOBL, AEs, and re-operation were compared. Subgroup analysis was performed on patient presenting with pre-operative malalignment (cervical sagittal vertical axis ≥40 mm and/or T1slope- cervical lordosis >15°).

RESULTS

173 patients were included, of which 41 (24%) had a C2 UIV and 132 (76%) a C3 UIV. There was no statistically significant difference between the groups for the changes in PROs up to 24 months. Subgroup analysis of patients with pre-operative malalignment showed a trend towards greater improvement in the NDI at 12 months with a C2 UIV (P = .054). Operative time, IOBL and peri-operative AEs were more in C2 group (P < .05). There was no significant difference in LOS and re-operation (P > .05).

CONCLUSION

In this observational study, up to 24 months after surgery for posterior cervical fusion in DCM greater than 3 levels, PROs appear to evolve similarly.

Latest knowledge on a comprehensive understanding of cervical deformity and selection of effective treatment methods using recent classification systems: a narrative review

Surgical treatment for patients with cervical spine deformities is challenging for both patients and doctors. For successful surgical treatment, mastery of processes is important to objectively evaluate and classify the degree of deformity. Recently, efforts have been increasing to systematically understand, evaluate, and effectively treat complex cervical spine deformities. Various parameters are being developed to quantify and objectively evaluate the degree of cervical spine deformity, and classification methods are being introduced to help establish the treatment scope by categorizing it according to the degree of deformity. However, a comprehensive and systematic understanding of complex deformities using only the currently introduced classification methods and related knowledge is not easy. Through this review, we aimed to introduce various classification methods and their pros and cons to evaluate cervical deformities, analyze their meaning, and provide a basic understanding of the evaluation and classification of patients with cervical spine deformities. This review also aimed to aid in the decision-making process for the treatment of cervical spine deformities by presenting a structured treatment algorithm based on recently known classification systems and lay the foundation for efficient treatment.

Predictive value of intraoperative contrast-enhanced ultrasound in functional recovery of non-traumatic cervical spinal cord injury

OBJECTIVES

To evaluate the ability of intraoperative CEUS to predict neurological recovery in patients with degenerative cervical myelopathy (DCM).

METHODS

Twenty-six patients with DCM who underwent laminoplasty and intraoperative ultrasound (IOUS) were included in this prospective study. The modified Japanese Orthopaedic Association (mJOA) scores and MRI were assessed before surgery and 12 months postoperatively. The anteroposterior diameter (APD), maximum spinal cord compression (MSCC), and area of signal changes in the cord at the compressed and normal levels were measured and compared using MRI and IOUS. Conventional blood flow and CEUS indices (time to peak, ascending slope, peak intensity (PI), and area under the curve (AUC)) at different levels during IOUS were calculated and analysed. Correlations between all indicators and the neurological recovery rate were evaluated.

RESULTS

All patients underwent IOUS and intraoperative CEUS, and the total recovery rate was 50.7 ± 33.3%. APD and MSCC improved significantly (p < 0.01). The recovery rate of the hyperechoic lesion group was significantly worse than that of the isoechoic group (p = 0.016). 22 patients were analysed by contrast analysis software. PI was higher in the compressed zone than in the normal zone (24.58 ± 3.19 versus 22.43 ± 2.39, p = 0.019). ΔPI compress-normal and ΔAUC compress-normal of the hyperechoic lesion group were significantly higher than those of the isoechoic group (median 2.19 versus 0.55, p = 0.017; 135.7 versus 21.54, p = 0.014, respectively), and both indices were moderately negatively correlated with the recovery rate (r =  - 0.463, p = 0.030; r =  - 0.466, p = 0.029).

CONCLUSIONS

Signal changes and microvascular perfusion evaluated using CEUS during surgery are valuable predictors of cervical myelopathy prognosis.

CLINICAL RELEVANCE STATEMENT

In the spinal cord compression area of degenerative cervical myelopathy, especially in the hyperechoic lesions, intraoperative CEUS showed more significant contrast agent perfusion than in the normal area, and the degree was negatively correlated with the neurological prognosis.

KEY POINTS

• Recovery rates in patients with hyperechoic findings were lower than those of patients without lesions detected during intraoperative ultrasound. • The peak intensity of CEUS was higher in compressed zones than in the normal parts of the spinal cord. • Quantitative CEUS comparisons of the peak intensity and area under the curve at the compressed and normal levels of the spinal cord revealed differences that were inversely correlated to the recovery rate.

Adult cervical spine deformity: a state-of-the-art review

Adult cervical deformity is a structural malalignment of the cervical spine that may present with variety of significant symptomatology for patients. There are clear and substantial negative impacts of cervical spine deformity, including the increased burden of pain, limited mobility and functionality, and interference with patients' ability to work and perform everyday tasks. Primary cervical deformities develop as the result of a multitude of different etiologies, changing the normal mechanics and structure of the cervical region. In particular, degeneration of the cervical spine, inflammatory arthritides and neuromuscular changes are significant players in the development of disease. Additionally, cervical deformities, sometimes iatrogenically, may present secondary to malalignment or correction of the thoracic, lumbar or sacropelvic spine. Previously, classification systems were developed to help quantify disease burden and influence management of thoracic and lumbar spine deformities. Following up on these works and based on the relationship between the cervical and distal spine, Ames-ISSG developed a framework for a standardized tool for characterizing and quantifying cervical spine deformities. When surgical intervention is required to correct a cervical deformity, there are advantages and disadvantages to both anterior and posterior approaches. A stepwise approach may minimize the drawbacks of either an anterior or posterior approach alone, and patients should have a surgical plan tailored specifically to their cervical deformity based upon symptomatic and radiographic indications. This state-of-the-art review is based upon a comprehensive overview of literature seeking to highlight the normal cervical spine, etiologies of cervical deformity, current classification systems, and key surgical techniques.

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

BACKGROUND

Although published data support the utilization of circumferential fusion to treat select cervical spine pathologies, it is unclear whether the posterior-anterior-posterior (PAP) fusion has increased risks compared with the anterior-posterior fusion.

OBJECTIVE

To evaluate the differences in perioperative complications between the 2 circumferential cervical fusion approaches.

METHODS

One hundred fifty-three consecutive adult patients who underwent single-staged circumferential cervical fusion for degenerative pathologies from 2010 to 2021 were retrospectively reviewed. Patients were stratified into the anterior-posterior ( n = 116) and PAP ( n = 37) groups. The primary outcomes assessed were major complications, reoperation, and readmission.

RESULTS

Although the PAP group was older ( P = .024), predominantly female ( P = .024), with higher baseline neck disability index ( P = .026), cervical sagittal vertical axis ( P = .001), and previous cervical operation rate ( P < .00001), the major complication, reoperation, and readmission rates were not significantly different from the 360° group. Although the PAP group had higher urinary tract infection ( P = .043) and transfusion ( P = .007) rates, higher estimated blood loss ( P = .034), and longer operative times ( P < .00001), these differences were insignificant after the multivariable analysis. Overall, operative time was associated with older age (odds ratio [OR] 17.72, P = .042), atrial fibrillation (OR 158.30, P = .045), previous cervical operation (OR 5.05, P = .051), and lower baseline C1 - 7 lordosis (OR 0.93, P = .007). Higher estimated blood loss was associated with older age (OR 1.13, P = .005), male gender (OR 323.31, P = .047), and higher baseline cervical sagittal vertical axis (OR 9.65, P = .022).

CONCLUSION

Despite some differences in preoperative and intraoperative variables, this study suggests both circumferential approaches have comparable reoperation, readmission, and complication profiles, all of which are high.

Distal junctional kyphosis in adult cervical deformity patients: where does it occur?

PURPOSE

To evaluate the impact of the lowest instrumented vertebra (LIV) on Distal Junctional kyphosis (DJK) incidence in adult cervical deformity (ACD) surgery.

METHODS

Prospectively collected data from ACD patients undergoing posterior or anterior-posterior reconstruction at 13 US sites was reviewed up to 2-years postoperatively (n = 140). Data was stratified into five groups by level of LIV: C6-C7, T1-T2, T3-Apex, Apex-T10, and T11-L2. DJK was defined as a kyphotic increase > 10° in Cobb angle from LIV to LIV-1. Analysis included DJK-free survival, covariate-controlled cox regression, and DJK incidence at 1-year follow-up.

RESULTS

25/27 cases of DJK developed within 1-year post-op. In patients with a minimum follow-up of 1-year (n = 102), the incidence of DJK by level of LIV was: C6-7 (3/12, 25.00%), T1-T2 (3/29, 10.34%), T3-Apex (7/41, 17.07%), Apex-T10 (8/11, 72.73%), and T11-L2 (4/8, 50.00%) (p < 0.001). DJK incidence was significantly lower in the T1-T2 LIV group (adjusted residual = -2.13), and significantly higher in the Apex-T10 LIV group (adjusted residual = 3.91). In covariate-controlled regression using the T11-L2 LIV group as reference, LIV selected at the T1-T2 level (HR = 0.054, p = 0.008) or T3-Apex level (HR = 0.081, p = 0.010) was associated with significantly lower risk of DJK. However, there was no difference in DJK risk when LIV was selected at the C6-C7 level (HR = 0.239, p = 0.214).

CONCLUSION

DJK risk is lower when the LIV is at the upper thoracic segment than the lower cervical segment. DJK incidence is highest with LIV level in the lower thoracic or thoracolumbar junction.

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.

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

PURPOSE

To study clinical and radiological outcomes of pediatric cervical kyphosis correction with a standalone posterior cervical approach. Cervical spine kyphotic deformity in pediatric age group is a distinct entity and the management is challenging. Pediatric cervical kyphosis is less often encountered, and literature is sparse with only few case series. Management algorithms are devised keeping the flexibility of the deformity at the core of decision making. Circumferential fusion is mostly recommended for non-flexible (rigid) kyphosis.

METHODS

Authors present a single center retrospective analysis of cases of pediatric cervical kyphosis managed by a standalone posterior approach. Pre- and post-operative clinical and radiological parameters were recorded and analyzed. Changes in neurological status, kyphosis correction and bony fusion were assessed. Surgical and implant related complications were noted.

RESULTS

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 in 1 case each. Mean kyphosis correction was 36.80±19.30 (87%±21%) with a mean pre-operative kyphosis angle of 37.80±15.30 and mean immediate post-operative kyphosis angle of 3.70±8.70. Mean hospital stay duration was 10±6 days. Median follow-up duration was 36 months. Myelopathy improved in 5 cases at last follow-up. Six cases demonstrated bony fusion at a mean follow-up of 8.4±1.5 months.

CONCLUSION

Significant immediate correction in pediatric cervical kyphosis may be achieved with a standalone posterior approach with proper planning and technique in selected cases. Inserting pedicle screws at strategic locations of implant construct offer better corrections and pull-out strength and maintain long-term stability resulting in higher arthrodesis rates. Larger studies with longer follow up are needed to further ascertain the role of standalone posterior cervical approaches in pediatric cervical kyphosis.

Cervical rotational osteotomy for correction of axial deformity in a patient with ankylosing spondylitis

PURPOSE

Severe cervical axial deformity associated with ankylosing spondylitis (AS) is rare in clinic, and there are little concerns about surgical treatment of axial deformity associated with AS. The case study aims to show the surgical technique to perform cervical rotational osteotomy.

METHODS

We present the case of a young AS patient whose neck was fixed in a left-rotational posture at 18°, requiring his trunk to be turned to the right to look forward visually. This made his gait appear to be limping, inconveniencing him with great difficulty. In order to correct this deformity, we performed a novel cervical rotational osteotomy through a one-stage posterior-anterior-posterior approach. Firstly, we performed laminectomies of C7 and T1, followed by a C7/T1 facetectomy with release of the bilateral C8 nerve roots. Next, we performed C7/T1 discectomy, bony resection of the lateral body and uncovertebral joints. The head of the patient was then rotated manually, so that both his face and torso were simultaneously facing frontward. Finally, rods spanning the screws from C6 to T2 were fixed.

RESULTS

Postoperatively, the patient's axial malalignment was significantly improved, and he was able to walk normally. Surgical outcomes were well maintained at a 3-year follow-up.

CONCLUSION

Through this case, we hope to draw the attention to spinal axial deformity and provide a reference point in the surgical treatment of spinal axial deformity.

Dropped head syndrome in a patient with Parkinson's disease and inflammatory myopathy, treated with sternocleidomastoid release and circumferential cervical fusion

BACKGROUND

Dropped head syndrome (DHS) is a recently recognised cause of cervical spinal deformity and disability. The combination of Parkinson's disease (PD) and inflammatory myopathy in the genesis of DHS has not been previously reported. Furthermore, the optimal surgical treatment of progressive DHS remains undefined.

CASE DESCRIPTION

We report the case of a 64-year-old patient with severe DHS and coronal plane deformity secondary to underlying PD, precipitated by a focal paraspinal myositis, successfully corrected using asymmetric sternocleidomastoid (SCM) release and circumferential cervical fusion. The nuances of decision-making in this challenging patient population are highlighted, including the benefits of intraoperative traction, anterior column reconstruction and bicortical screw fixation. Postoperatively, significant reductions in pain and disability were achieved, along with restoration of cervical lordosis (CL), C2-7 sagittal vertical axis (CSVA) and chin-brow vertical angle (CBVA).

CONCLUSIONS

Circumferential cervical fusion with concomitant SCM release is a useful option in the treatment of recalcitrant DHS with biplanar deformity, addressing the unique biomechanical and endocrinological challenges posed by patients with underlying PD.

Radiographic Characteristics of Cervical Deformity (CD) Using a Discriminant Analysis: The Value of Extension Radiographs

STUDY DESIGN

This was a retrospective review of a prospectively collected database.

OBJECTIVE

The aim of this study was to delineate radiographic parameters that distinguish severe cervical spine deformity (CSD).

SUMMARY OF BACKGROUND DATA

Our objective was to define parameters that distinguish severe CSD using a consensus approach combined with discriminant analysis as no system currently exists in the literature.

METHODS

Twelve CSD surgeons reviewed preoperative x-rays from a CSD database. A consensus was reached for categorizing patients into a severe cervical deformity (sCD), non-severe cervical deformity (non-sCD), or an indeterminate cohort. Radiographic parameters were found including classic cervical and spinopelvic parameters in neutral/flexion/extension alignment. To perform our discriminant analysis, we selected for parameters that had a significant difference between the sCD and non-sCD groups using the Student t test. A discriminant function analysis was used to determine which variables discriminate between the sCD versus non-sCD. A stepwise analysis was performed to build a model of parameters to delineate sCD.

RESULTS

A total of 146 patients with cervical deformity were reviewed (60.5±10.5 y; body mass index: 29.8 kg/m2; 61.3% female). There were 83 (56.8%) classified as sCD and 51 (34.9%) as non-sCD. The comparison analysis led to 16 radiographic parameters that were different between cohorts, and 5 parameters discriminated sCD and non-sCD. These parameters were cervical sagittal vertical axis, T1 slope, maximum focal kyphosis in extension, C2 slope in extension, and number of kyphotic levels in extension. The canonical coefficient of correlation was 0.689, demonstrating a strong association between our model and cervical deformity classification. The accuracy of classification was 87.0%, and cross-validation was 85.2% successful.

CONCLUSIONS

More than one third of a series of CSD patients were not considered to have a sCD. Analysis of an initial 17 parameters showed that a subset of 5 parameters can discriminate between sCD versus non-sCD with 85% accuracy. Our study demonstrates that flexion/extension images are critical for defining severe CD.

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.

A 540° posterior-anterior-posterior approach for 360° fused rigid severe cervical kyphosis: patient series

BACKGROUND

Treatment of severe rigid 360° fused cervical kyphosis (CK) is challenging and often requires a combined approach for ankylosis release, establishment of sagittal balance, and fixation with fusion.

OBSERVATIONS

Four patients with iatrogenic 360° fused severe rigid CK (Cobb angle ≥40°) were enrolled for this retrospective analysis. All patients in the case series were female, with an average age of 27 years. All patients previously underwent posterior laminectomy/laminoplasty and cervical tumor resection when they were children (13–17 years). They underwent correction surgery with a 540° posterior-anterior-posterior approach. Preoperative and final follow-up radiography and computed tomography (CT) were used to evaluate kyphosis correction, internal fixation implants, and bone fusion. The preoperative and final follow-up average C2–7 Cobb angles were −32.4° ± 12.0° and 5.3° ± 7.1°, respectively. Preoperative and final follow-up CK angles averaged −47.2° ± 7.4° and −0.9° ± 16.1°, respectively. The mean correction angle was 46.3° ± 9.6°. At final follow-up, CT showed stable fixation and solid bone fusion.

LESSONS

The rare iatrogenic severe kyphosis with 360° ankylosis requires a combined approach. The 540° posterior-anterior-posterior approach can completely release the bony fusion, and the CK can be corrected using an anterior plate. This technique can achieve good results and is an effective strategy.

Optimizing cervicothoracic junction biomechanics after C7 pedicle subtraction osteotomy: a cadaveric study of stability and rod strain

OBJECTIVE

To compare biomechanical stability and rod strain among uniform rod (UR), tapered rod (TR), and uniform rod plus accessory rod (UR+AR) constructs in a human cadaveric C7 pedicle subtraction osteotomy (PSO) model of cervical deformity correction.

METHODS

Fourteen human cadaveric C2-T4 specimens were divided into 2 statistically equivalent groups. Specimens were instrumented from C2 to T3, and a 25° PSO was performed at C7. Group 1 was instrumented with 3.5-5.5-mm titanium TRs, and group 2 received 4.0-mm titanium URs. The UR group was also tested with lateral 4.0-mm titanium ARs (UR+AR) at C5-T2. All conditions were tested with 2.0 Nm pure moment and 70 N compressive load. Intervertebral range of motion (ROM) and posterior rod strain (pRS) were measured at C2-C3, T2-T3, and the PSO level. Statistical comparisons used one-way analysis of variance.

RESULTS

ROM was significantly reduced in the TR versus UR construct for right axial rotation (p=0.04) at the PSO level; ROM with TR was significantly greater than with UR and UR+AR in compression (p≤0.02). At the PSO level, pRS was significantly greater in TR than in UR+AR in flexion, extension, and right axial rotation (p≤0.02). At T2/3, pRS was higher in UR than TR in left axial rotation (p=0.003).

CONCLUSIONS

C7 PSO is highly destabilizing. Maximal rod strain was concentrated across the PSO and the cranial fixation site. TR provided higher stability than UR in one direction of movement; however, UR+AR provided the greatest reduction of pRS.

"The Circle" Predicts Extent of Fusion for Surgical Correction of Cervical Spinal Kyphotic Deformities: Proof of Concept

BACKGROUND

Correction of kyphotic deformities of the spine is a common problem faced by spine surgeons. Unfortunately, there are no clear published guidelines available regarding the extent of spinal fusion required to achieve and maintain lasting deformity correction.

OBJECTIVE

The authors aim to share a set of novel radiographic parameter ("the Circle") that can be used as a guideline for determining the extent of fusion required in surgical correction of spinal kyphotic deformity.

METHODS

A Google forms survey was distributed amongst spine surgeons and trainees to evaluate differences in recommend extent of posterior-approach fusions for cervical spinal kyphotic deformities before and after introduction to "the Circle". Extent of fusion before and after use of "the Circle" were qualitatively and quantitatively analyzed. Data was anonymized and stored in a secure database.

RESULTS

Twenty-seven neurosurgical attendings (n=14), residents (n=9) and fellows (n=3) responded to the survey. Variance between predicted upper and lower instrumented vertebrae, and length of construct, was statistically significantly decreased after application of "the Circle" in almost all cases. Respondents rated the ease of use of "the Circle" an average of 4.2/5 (5 = the most ease). The majority of participants (92/6%; n=25/27) stated that they would or would likely use "the Circle" as a radiographic tool in the surgical planning for correction of cervical spinal kyphotic deformities in the future.

CONCLUSION

"The Circle" is a novel radiographic parameter that may be used to educate and guide surgical plans and extent of fusion when aiming to correct spinal kyphotic deformities.

Association of findings on preoperative extension lateral cervical radiography with osteotomy type, approach, and postoperative cervical alignment after cervical deformity surgery

OBJECTIVE

The authors' objective was to determine whether preoperative lateral extension cervical spine radiography can be used to predict osteotomy type and postoperative alignment parameters after cervical spine deformity surgery.

METHODS

A total of 106 patients with cervical spine deformity were reviewed. Radiographic parameters on preoperative cervical neutral and extension lateral radiography were compared with 3-month postoperative radiographic alignment parameters. The parameters included T1 slope, C2 slope, C2-7 cervical lordosis, cervical sagittal vertical axis, and T1 slope minus cervical lordosis. Associations of radiographic parameters with osteotomy type and surgical approach were also assessed.

RESULTS

On extension lateral radiography, patients who underwent lower grade osteotomy had significantly lower T1 slope, T1 slope minus cervical lordosis, cervical sagittal vertical axis, and C2 slope. Patients who achieved more normal parameters on extension lateral radiography were more likely to undergo surgery via an anterior approach. Although baseline parameters were significantly different between neutral lateral and extension lateral radiographs, 3-month postoperative lateral and preoperative extension lateral radiographs were statistically similar for T1 slope minus cervical lordosis and C2 slope.

CONCLUSIONS

Radiographic parameters on preoperative extension lateral radiography were significantly associated with surgical approach and osteotomy grade and were similar to those on 3-month postoperative lateral radiography. These results demonstrated that extension lateral radiography is useful for preoperative planning and predicting postoperative alignment.

Cervical fusion for treatment of degenerative conditions: development of appropriate use criteria

BACKGROUND CONTEXT

High quality evidence is difficult to generate, leaving substantial knowledge gaps in the treatment of spinal conditions. Appropriate use criteria (AUC) are a means of determining appropriate recommendations when high quality evidence is lacking.

PURPOSE

Define appropriate use criteria (AUC) of cervical fusion for treatment of degenerative conditions of the cervical spine.

STUDY DESIGN/SETTING

Appropriate use criteria for cervical fusion were developed using the RAND/UCLA appropriateness methodology. Following development of clinical guidelines and scenario writing, a one-day workshop was held with a multidisciplinary group of 14 raters, all considered thought leaders in their respective fields, to determine final ratings for cervical fusion appropriateness for various clinical situations.

OUTCOME MEASURES

Final rating for cervical fusion recommendation as either "Appropriate," "Uncertain" or "Rarely Appropriate" based on the median final rating among the raters.

METHODS

Inclusion criteria for scenarios included patients aged 18 to 80 with degenerative conditions of the cervical spine. Key modifiers were defined and combined to develop a matrix of clinical scenarios. The median score among the raters was used to determine the final rating for each scenario. The final rating was compared between modifier levels. Spearman's rank correlation between each modifier and the final rating was determined. A multivariable ordinal regression model was fit to determine the adjusted odds of an "Appropriate" final rating while adjusting for radiographic diagnosis, number of levels and symptom type. Three decision trees were developed using decision tree classification models and variable importance for each tree was computed.

RESULTS

Of the 263 scenarios, 47 (17.9 %) were rated as rarely appropriate, 66 (25%) as uncertain and 150 (57%) were rated as appropriate. Symptom type was the modifier most strongly correlated with the final rating (adjusted ρ2 = 0.58, p<.01). A multivariable ordinal regression adjusting for symptom type, diagnosis, and number of levels and showed high discriminative ability (C statistic = 0.90) and the adjusted odds ratio (aOR) of receiving a final rating of "Appropriate" was highest for myelopathy (aOR, 7.1) and radiculopathy (aOR, 4.8). Three decision tree models showed that symptom type and radiographic diagnosis had the highest variable importance.

CONCLUSIONS

Appropriate use criteria for cervical fusion in the setting of cervical degenerative disorders were developed. Symptom type was most strongly correlated with final rating. Myelopathy or radiculopathy were most strongly associated with an "Appropriate" rating, while axial pain without stenosis was most associated with "Rarely Appropriate."

Circumferential Operations of the Cervical Spine

Generally, a combined anterior and posterior cervical approach is associated with significant morbidity since it requires an extended operative time, greater intraoperative blood loss, and both anterior- and posterior-related surgical complications. However, there are some instances where a circumferential cervical fusion can be advantageous. Our objective is to discuss the indications for circumferential cervical spine procedures. A narrative review of the literature was performed. We include the indications for circumferential cervical approaches of the senior author (KDR). Indications for circumferential approaches include: (1) high-risk patients for pseudoarthrosis, (2) cervical deformity (e.g., degenerative, posttraumatic, cervicothoracic kyphosis), (3) cervical spine metastases (especially those with multilevel involvement), (4) cervical spine infection, (5) unstable cervical trauma, (6) movement disorders and cerebral palsy, (7) Multiply operated patient (especially postlaminectomy kyphosis and patients with massive ossification of the posterior longitudinal ligament), and when (8) early fusion is desirable. Circumferential procedures may be useful in many different cervical spine conditions requiring surgery. Despite its advantages, particularly with reducing the risk for pseudarthrosis, the benefits of a combined approach must be weighed against the risks associated with a dual approach. With appropriate preoperative planning, intraoperative decision-making, and surgical techniques, excellent clinical outcomes can be achieved.

Degenerative Cervical Myelopathy: Insights into Its Pathobiology and Molecular Mechanisms

Degenerative cervical myelopathy (DCM), earlier referred to as cervical spondylotic myelopathy (CSM), is the most common and serious neurological disorder in the elderly population caused by chronic progressive compression or irritation of the spinal cord in the neck. The clinical features of DCM include localised neck pain and functional impairment of motor function in the arms, fingers and hands. If left untreated, this can lead to significant and permanent nerve damage including paralysis and death. Despite recent advancements in understanding the DCM pathology, prognosis remains poor and little is known about the molecular mechanisms underlying its pathogenesis. Moreover, there is scant evidence for the best treatment suitable for DCM patients. Decompressive surgery remains the most effective long-term treatment for this pathology, although the decision of when to perform such a procedure remains challenging. Given the fact that the aged population in the world is continuously increasing, DCM is posing a formidable challenge that needs urgent attention. Here, in this comprehensive review, we discuss the current knowledge of DCM pathology, including epidemiology, diagnosis, natural history, pathophysiology, risk factors, molecular features and treatment options. In addition to describing different scoring and classification systems used by clinicians in diagnosing DCM, we also highlight how advanced imaging techniques are being used to study the disease process. Last but not the least, we discuss several molecular underpinnings of DCM aetiology, including the cells involved and the pathways and molecules that are hallmarks of this disease.

Pedicle Subtraction Osteotomy for Deformity Correction in the Upper Cervical Spine: A Technical Note

BACKGROUND

 Kyphosis is the most common deformity of the cervical spine leading to development of severe disabilities. In case of fused kyphosis, surgical treatment can be demanding and often requires multiple-step procedures for adequate correction. We present a technique of single-stage pedicle subtraction osteotomy (PSO) of C3 to treat a patient with fused kyphosis of C2 and C3 causing spinal stenosis with subsequent myelopathy.

METHODS

 A 53-year-old man presented with progressive myelopathy not able to walk with 6/18 points on the modified Japanese Orthopedic Association scale. Horizontal gaze was lost due to cervical kyphosis. Magnetic resonance imaging (MRI) revealed a cervical kyphosis causing stenosis, cord compression, and kinking; computed tomography (CT) showed substantial anterior and posterior fusion of C2 and C3.

RESULTS

 Surgery included decompression via laminectomy of C2 to C6 in combination with PSO of C3 and additional dorsal instrumentation of C2 to C6. Cervical spinal alignment was corrected, as the C2-C4 Cobb angle was reduced from 48.9 to 20.6 degrees. Horizontal gaze was restored. Postoperative MRI demonstrated full decompression of the cord without kinking of the vertebral arteries. No complications were noted. The patient recovered well with restoration of his ability to walk.

CONCLUSION

 Single-stage pedicle subtraction closing wedge osteotomy in the upper cervical spine, although a demanding surgical procedure, is an alternative treatment option in selected cases of fused and severe cervical kyphosis. In contrast to multiple-step approaches, the single-stage procedure could reduce operating time and may thus decrease complications.

Severe, rigid cervical kyphotic deformity associated with SAPHO syndrome successfully treated with three-stage correction surgery combined with C7 vertebral column resection: a technical case report

STUDY DESIGN

Case report.

OBJECTIVES

To describe the first reported use of corrective surgery combined with C7 vertebral column resection (VCR) to treat an extremely rare case of severe, rigid cervical kyphotic deformity associated with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome.

BACKGROUND DATA

Spinal lesions reportedly occur in 32-45% in SAPHO syndrome. However, bone and joint lesions are usually repaired such that severe joint destruction is rare. Therefore, there have been few reported cases of surgical treatment for spinal lesions.

METHODS

A 22-year-old woman had been diagnosed with cervical kyphotic deformity associated with SAPHO syndrome. She had difficulty looking upward. On radiography, the C4-C7 vertebral bodies were fused and exhibited severe rigid kyphotic deformity. Right convex scoliosis with a Cobb angle of 22° was apparent at C5-T2, and the C2-C7 angle of kyphosis was 75°. Corrective three-stage surgery was carried out from the anterior, posterior, and anterior, with C7 VCR.

RESULTS

The C2-T1 angle improved to 21° and the patient was capable of looking up. At present, 2 years postoperatively, complete bony fusion has been achieved. Her cervical spine function and quality of life were markedly improved.

CONCLUSION

Only a very limited number of patients have a deformity sufficiently severe that VCR of cervical vertebra is required, but as this is the technique that provides the greatest multiplanar alignment correction, its choice in the present case was appropriate.

LEVEL OF EVIDENCE

IV.

Cervical Deformity: Evaluation, Classification, and Surgical Planning

Cervical deformity is a challenging condition to treat and requires complex decision-making. Apart from a thorough history and physical examination, a thoughtful and quantitative analysis of multiple imaging modalities is critical for understanding the nature and driver of the cervical deformity. A few classification schemes have emerged, and it is now clear that dynamic films are invaluable as they capture the extension reserve that patients can use to compensate for malalignment. These classification systems can help guide surgical planning, because the various subgroups have different properties that lend themselves to specific treatment paradigms. Here we review the clinical and radiographic evaluation, classification, and surgical planning for cervical deformity.

Complex Revision Surgery for Cervical Deformity or Implant Failure

Postoperative cervical deformity sometimes occurs in the short or long term after primary surgery for cervical disorders related to the degenerative aging spine, neoplastic etiologies, hemodialysis, infection, inflammation, trauma, etc. Cervical kyphosis after posterior decompression surgery, such as laminectomy or laminoplasty, is a common problem for spine surgeons. However, revision surgery for cervical deformity is definitely one of the most challenging areas for spine surgeons. There is no doubt that surgery for cervical deformity carries a high risk of surgery-related complications that might result in aggravation of health-related quality of life. Revision surgery is even more challenging. Hence, spine surgeons need to assess carefully the overall severity of the underlying condition before revision surgery, and try to refine the surgical strategy to secure safe surgery. Needless to say, spine surgeons are now facing great challenges in making spine surgery a much more reliable and convincing entity.

Cervical Deformity Arising From Upper Thoracic Malalignment

This study aims to describe the surgical management of cervical deformity arising from outside the cervical spine because of upper thoracic malalignment, using pedicle subtraction osteotomy (PSO). Cervical spine deformity is a complex topic and it can be generally divided into 2 categories, the first category is when the primary deformity is inside the cervical spine and the treatment will focus on the cervical spine itself, whereas the second category is when the primary deformity is outside the cervical spine usually in the adjacent upper thoracic area, the cervical deformity is a compensation for the adjacent malalignment, and thus in this situation, the management will occur in the upper thoracic area. Description of a single surgeon’s technique for performing PSO to treat rigid upper thoracic deformity. PSO in the upper thoracic spine is a safe and effective procedure and can result in satisfying clinical and radiological outcome with indirect correction of the compensatory cervical deformity. Cervical deformity arising from upper thoracic malalignment should be dealt with by treating the problem at its origin outside the cervical spine by performing a PSO in the upper thoracic spine.

Anterior Reconstruction Techniques for Cervical Spine Deformity

Cervical spine deformity is an uncommon yet severely debilitating condition marked by its heterogeneity. Anterior reconstruction techniques represent a familiar approach with a range of invasiveness and correction potential-including global or focal realignment in the sagittal and coronal planes. Meticulous preoperative planning is required to improve or prevent neurologic deterioration and obtain satisfactory global spinal harmony. The ability to perform anterior only reconstruction requires mobility of the opposite column to achieve correction, unless a combined approach is planned. Anterior cervical discectomy and fusion has limited focal correction, but when applied over multiple levels there is a cumulative effect with a correction of approximately 6° per level. Partial or complete corpectomy has the ability to correct sagittal deformity as well as decompress the spinal canal when there is anterior compression behind the vertebral body. If pathoanatomy permits, a hybrid discectomy-corpectomy construct is favored over multilevel corpectomies. The anterior cervical osteotomy with bilateral complete uncinectomy may be necessary for angular correction of fixed cervical kyphosis, and is particularly useful in the midcervical spine. A detailed understanding of the patient's local anatomy, careful attention to positioning, and avoiding long periods of retraction time will help prevent complications and iatrogenic injury.

Utility of a Novel Biomimetic Spine Model in Surgical Education: Case Series of Three Cervicothoracic Kyphotic Deformities

STUDY DESIGN

Evaluation of new technology.

OBJECTIVES

To evaluate the utility of a novel biomimetic spine model as a surgical planning and education resource in the treatment of cervical spine deformities (CSD).

METHODS

Three patients with CSD were identified and synthetic spine models were manufactured to match the anatomical and biomechanical properties of each patient. Each model underwent 3 phases of surgical correction: maximum correction with no osteotomies performed, with posterior column osteotomies (PCOs) only, and with PCOs and a 3-column osteotomy (3CO). Lateral fluoroscopic films were obtained after each phase of correction for measurement of cervical lordosis. Surgeons were surveyed to obtain subjective feedback on the perceived model utility.

RESULTS

Each model began with a kyphotic deformity that was mobile, rigid, or fixed. The mobile model achieved successive lordotic correction with each phase of correction. The rigid and fixed models achieved much less correction with no osteotomies and PCOs only, and the majority of correction with 3COs. Each model predicted with varying, but overall high, accuracy the amount of correction achieved in each patient. The surgeons felt the model had very high utility as a surgical education platform.

CONCLUSIONS

The models appeared to accurately replicate the gross anatomy and biomechanical performance of the patients' spines. This high fidelity to the individual patient's anatomy, bone quality, and segmental mobility resulted in a custom model that provides an invaluable learning platform for surgical education. These results suggest the models may have utility in surgical planning, but further studies are needed.

Total subaxial reconstruction

Cervical deformity, particularly kyphosis, is frequently encountered in surgical practice. While many cases are asymptomatic, some patients may have significant pain and disability. We provide a brief review of the pathophysiology of cervical deformity and the technical aspects of deformity correction in the cervical spine. Anterior techniques reviewed here include anterior cervical discectomy and fusion (ACDF), anterior corpectomy and fusion (ACCF) and anterior osteotomy (ATO). Posterior techniques include laminectomy and fusion, posterior column osteotomy (PCO) and pedicle subtraction osteotomy (PSO). This is a fast-evolving field as our understanding of cervical deformity matures and longer-term surgical outcomes are available.

Anterior osteotomy for rigid cervical deformity correction

Rigid deformities of the cervical spine can be associated with significant pain, disability, and impaired quality of life. Historical treatments generally utilized posterior approaches including the opening wedge osteotomy and pedicle subtraction osteotomy (PSO). Translation can occur during osteoclasis of the opening wedge osteotomy, making it inherently less stable than a PSO. The PSO is limited to lower cervical or upper thoracic levels due to the vertebral artery and sensitivity of cervical nerve roots to compression during osteotomy closure. The anterior osteotomy, defined as an osteotomy through the cervical disc space and uncovertebral joints back to the level of the transverse foramen bilaterally, is a powerful correction technique that can be applied throughout the cervical spine. It can also be used to correct deformities in the coronal plane. This review will summarize the technical nuances of the anterior osteotomy including patient selection, preoperative planning, and surgical technique.

The morphology of cervical deformities: a two-step cluster analysis to identify cervical deformity patterns

OBJECTIVE

Cervical deformity (CD) is difficult to define due to the high variability in normal cervical alignment based on postural- and thoracolumbar-driven changes to cervical alignment. The purpose of this study was to identify whether patterns of sagittal deformity could be established based on neutral and dynamic alignment, as shown on radiographs.

METHODS

This study is a retrospective review of a prospective, multicenter database of CD patients who underwent surgery from 2013 to 2015. Their radiographs were reviewed by 12 individuals using a consensus-based method to identify severe sagittal CD. Radiographic parameters correlating with health-related quality of life were introduced in a two-step cluster analysis (a combination of hierarchical cluster and k-means cluster) to identify patterns of sagittal deformity. A comparison of lateral and lateral extension radiographs between clusters was performed using an ANOVA in a post hoc analysis.

RESULTS

Overall, 75 patients were identified as having severe CD due to sagittal malalignment, and they formed the basis of this study. Their mean age was 64 years, their body mass index was 29 kg/m2, and 66% were female. There were significant correlations between focal alignment/flexibility of maximum kyphosis, cervical lordosis, and thoracic slope minus cervical lordosis (TS-CL) flexibility (r = 0.27, 0.31, and -0.36, respectively). Cluster analysis revealed 3 distinct groups based on alignment and flexibility. Group 1 (a pattern involving a flat neck with lack of compensation) had a large TS-CL mismatch despite flexibility in cervical lordosis; group 2 (a pattern involving focal deformity) had focal kyphosis between 2 adjacent levels but no large regional cervical kyphosis under the setting of a low T1 slope (T1S); and group 3 (a pattern involving a cervicothoracic deformity) had a very large T1S with a compensatory hyperlordosis of the cervical spine.

CONCLUSIONS

Three distinct patterns of CD were identified in this cohort: flat neck, focal deformity, and cervicothoracic deformity. One key element to understanding the difference between these groups was the alignment seen on extension radiographs. This information is a first step in developing a classification system that can guide the surgical treatment for CD and the choice of fusion level.

Severe Cervical Spinal Kyphosis: Technical Case Reports on the Way of Microsurgical Management

A young man presented with quadriparesis due to severe kyphosis of the cervical spine. In the first posterior operation, the spinal cord was decompressed by laminectomies and posterior partial corpectomy through bilateral translateral mass and transforaminal approach followed by posterior stabilization and fusion. In the second operation, the cervical spine was stabilized and fused through an anterior approach. The patient recovered completely from his neurological deficit with very minimal neck movements. We report this case to describe the bilateral translateral mass and transforaminal partial posterior cervical corpectomy for spinal cord decompression followed by posterior and anterior stabilization and fusion.

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.

Limited morbidity and possible radiographic benefit of C2 vs. subaxial cervical upper-most instrumented vertebrae

Background

The study aims to evaluate differences in alignment and clinical outcomes between surgical cervical deformity (CD) patients with a subaxial upper-most instrumented vertebra (UIV) and patients with a UIV at C2. Use of CD-corrective instrumentation in the subaxial cervical spine is considered risky due to narrow subaxial pedicles and vertebral artery anatomy. While C2 fixation provides increased stability, the literature lacks guidelines indicating extension of CD-corrective fusion from the subaxial spine to C2.

Methods

Included: operative CD patients with baseline (BL) and 1-year postop (1Y) radiographic data, cervical UIV ≥ C2. Patients were grouped by UIV: C2 or subaxial (C3-C7) and propensity score matched (PSM) for BL cSVA. Mean comparison tests assessed differences in BL and 1Y patient-related, radiographic, and surgical data between UIV groups, and BL-1Y changes in alignment and clinical outcomes.

Results

Following PSM, 31 C2 UIV and 31 subaxial UIV patients undergoing CD-corrective surgery were included. Groups did not differ in BL comorbidity burden (P=0.175) or cSVA (P=0.401). C2 patients were older (64 vs. 58 yrs, P=0.010) and had longer fusions (9 vs. 6 levels, P=0.002). Overall, patients showed BL-1Y improvements in TS-CL (P<0.001), cSVA (P=0.005), McGS (P=0.004). Cervical flexibility was maintained at 1Y regardless of UIV, assessed by CL flexion (-0.2° vs. 6.0°, P=0.115) and extension (13.9° vs. 9.9°, P=0.366). While both subaxial and C2 patients showed BL-1Y improvements in McGS (both P<0.030), C2 patients improved to a larger degree (7.3° vs. 6.2°). Between UIV groups, there were no differences in BL-1Y changes in HRQLs, overall complication rates, or operative complication rates (all P>0.05).

Conclusions

C2 UIV patients showed similar cervical range of motion and baseline to 1-year functional outcomes as patients with a subaxial UIV. C2 UIV patients also showed greater baseline to 1-year horizontal gaze improvement and had complication profiles similar to subaxial UIV patients, demonstrating the radiographic benefit and minimal functional loss associated with extending fusion constructs to C2. In the treatment of adult cervical deformities, extension of the reconstruction construct to the axis may allow for certain clinical benefits with less morbidity than previously acknowledged.

Radiological and Clinical Outcome after Multilevel Anterior Cervical Discectomy and/or Corpectomy and Fixation

BACKGROUND

Multilevel anterior cervical decompression and fixation of four and more levels is a common surgical procedure used for several diseases.

METHODS

We reviewed the radiological and clinical outcomes after anterior cervical discectomy or corpectomy and fixation of four and more levels in 85 patients (55 men and 30 women) with an average age of 59.6 years. Surgical indication was multilevel cervical degenerative myelopathy and radiculopathy in 72 (85%) patients, multilevel cervical spondylodiscitis in four (5%), complex traumatic cervical fractures in four (5%), metastatic cervical spine tumor in two (2%), and ossification of the posterior longitudinal ligament in three (3%) patients.

RESULTS

There were no severe intraoperative complications such as spinal cord or vertebral artery injury or dissection. Seventy-three patients had four, 10 patients had five, and two patients had six anterior cervical level fixations. The visual analog scale (VAS) and Japanese Orthopedic Association (mJOA) scale scores improved (6.9 to 1.3 (p < 0.001) and 13.9 to 16.5 (p < 0.001), respectively). The Cobb angle increased from 5.7° to 17.6° postoperatively (p < 0.001). Secondary posterior fixation was necessary in three cases due to pseudarthrosis.

CONCLUSION

The anterior approach appears to be optimal for ventral compressive pathology and lordosis restoration to the cervical spine. Limitations of multiple level decompression and fixation included increasing pseudoarthrosis rates, especially after corpectomy, and increasing fused level numbers.

Cervical Kyphosis

Cervical kyphosis is a rare condition that can cause significant functional disability and myelopathy. Deciding the appropriate treatment for such deformities is challenging for the surgeon. Patients often present with axial neck pain, and it is not uncommon to find coexisting radiculopathy or myelopathy. The optimal approach for addressing this complex issue remains controversial. A comprehensive surgical plan based on knowledge of the pathology and biomechanics is important for kyphosis correction. Here we reviewed diagnoses of the cervical spine along with the literature pertaining to various approaches and management of cervical spine.