Circumferential fusion for cervical kyphotic deformity

An Algorithmic Roadmap for the Surgical Management of Degenerative Cervical Myelopathy: A Narrative Review

Degenerative cervical myelopathy (DCM) is a leading cause of disability, and its surgical management is crucial for improving patient neurological outcomes. Given the varied presentations and severities of DCM, treatment options are diverse. Surgeons often face challenges in selecting the most appropriate surgical approach because there is no universally correct answer. This narrative review aimed to aid the decision-making process in treating DCM by presenting a structured treatment algorithm. The authors categorized surgical scenarios based on an algorithm, outlining suitable treatment methods for each case. Four primary scenarios were identified based on the number of levels requiring surgery and K-line status: (1) K-line (+) and ≤3 levels, (2) K-line (+) and ≥3 levels, (3) K-line (-) and ≤3 levels, and (4) K-line (-) and ≥3 levels. This categorization aids in determining the appropriateness of anterior or posterior approaches and the necessity for fusion, considering the surgical level and K-line status. The complexity of surgical situations and diversity of treatment methods for DCM can be effectively managed using an algorithmic approach. Furthermore, surgical techniques that minimize the stages and address challenging conditions could enhance treatment outcomes in DCM.

Surgical management of idiopathic acute cervical kyphosis; A case-based review of an extremely rare entity

INTRODUCTION AND IMPORTANCE

Acute idiopathic cervical kyphosis (AICK) represents a rare entity, and its management remains controversial. Preoperative surgical planning and individual decision-making seem necessary. To date, there is a lack of sufficient evidence and clear guidelines.

CASE PRESENTATION

A 21-year-old male was referred with a progressive cervical deformity detected 3 months earlier. The patient suffered from severe progressive myelopathy and represented neither neck trauma nor a familial history of similar expected conditions. His cervical imaging revealed 95 degrees of cervical kyphosis. After 3 separate surgical sessions for 360-degree fixation, the cervical kyphosis was reduced by 90 degrees. No facet dislocation was observed, and laminectomy was unnecessary. Post-operative neurological examination detected significant improvement. Six months and 2-year follow-ups were favorable. To the authors' knowledge, the current case had the most extensive degree of cervical kyphosis reported in the literature.

CLINICAL DISCUSSION

Multistage correction of AICK would result in a favorable outcome and reduce the risk of complications. Particular attention should be paid to the wide inter-spinous spaces in high grades of kyphosis during sub-periosteal dissection to prevent iatrogenic spinal cord injuries.

CONCLUSION

The present work may provide the first report on the role of cervical postural habits in patients with opiate substance abuse disorder, which could have triggered cervical kyphosis in this particular patient. Multistage correction of AICK would result in a favorable outcome and reduce the risk of complications.

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.

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.

Multilevel Corpectomy for Subaxial Cervical Spondylodiscitis: Literature Review and Role of Navigation, Intraoperative Imaging and Augmented Reality

BACKGROUND

Subaxial cervical spine spondylodiscitis represents a real challenge in spine surgery. In later stages multiple spinal metamers can the interested by the pathological infection and the alteration of the spinal stability leading to spinal deformity. There is scant literature on subaxial cervical spondylodiscitis management and especially on ≥three-level cervical corpectomies. The authors conducted a literature search on this specific topic and presented an emblematic case of a patient treated with circumferential cervical fixation and four-level cervicothoracic corpectomy.

MATERIALS AND METHODS

A comprehensive literature review was performed using the combined Medical Subject Headings (MeSH) terms (multilevel) AND (sub axial spine OR cervical spine) AND (spine osteomyelitis OR spinal osteomyelitis), to search in the PubMed and Scopus databases. Our case was also included in this literature review. From our literature search the authors selected 13 papers, eight were excluded because they did not match our inclusion criteria (the involvement of only one or two levels, or did not perform corpectomy, discectomy, or cervical spine localization). The authors also presented a 71-year-old patient, in poor general clinical status who underwent several cage repositioning, with a final four-level corpectomy (C5, C6, C7, and T1), expandable C5-T1 cage positioning and C4-T2 anterior plating performed merging augmented reality, neuronavigation and intraoperative imaging.

RESULTS

This systematic review included 28 patients treated with ≥ three-level corpectomy (11 patients with three-level corpectomy, 15 patients with four-level corpectomy, and 2 patients with six-level corpectomy), 6 women, 5 men, and 17 not reported specifically, with a mean age of 55.9 years (range: 44-72 years). The combined anterior and posterior approach was taken in all but one case, which was treated with the anterior approach only. In one case of six-level cervicothoracic corpectomy, sternotomy was necessary. All reported patients recovered after surgery, except one who died after nosocomial pneumonia. No major intraoperative complications were reported. Usual postoperative complications include wound hematoma, pneumonia, subsidence, epidural hematoma, dural leakage, dysphagia, soft tissue swelling. The mean follow-up time was 31.9 months (range: 8-110 months).

CONCLUSION

According to the literature search performed by the authors, multilevel corpectomies for cervical spinal osteomyelitis is a safe and effective complex surgical procedure, even in extended procedures involving up to six levels or those at the cervicothoracic junction. The use multimodal navigation merging intraoperative imaging acquisition, navigation, and augmented reality may provide useful information during implant positioning in complex and altered anatomy and for assessing the best final result.

Classification(s) of Cervical Deformity

Cervical spine deformities (CSD) are complex surgical issues with currently heterogenous management strategies. The classification of CSD is still an evolving field. Rudimentary classification schemas were initially proposed in the late 20th century but were largely informal and based on the underlying etiology (i.e. , postsurgical, traumatic, or inflammatory). The first formal classification schema was proposed by Ames et al. in 2015 who established a standard nomenclature for describing these deformities. This classification system established 5 deformity descriptors based on curve apex location (cervical, cervicothoracic, thoracic, craniovertebral junctional, and coronal deformities) and 5 deformity modifiers which helped surgeons utilize a standard language when discussing CSD patients. Koller et al. in 2019 subsequently established a classification system for patients with rigid cervical kyphosis based on regional and global sagittal alignment. Most recently, Kim et al. in 2020 proposed an updated classification system utilizing dynamic cervical spine imaging to guide surgical treatment of CSD patients. It identified 4 major groups of deformities - (1) those with "flat-neck" deformities caused by cervical lordosis T1 slope mismatch; (2) those with focal kyphotic deformities between 2 cervical vertebrae; (3) those with cervicothoracic deformities caused by large T1 slope; and (4) those with coronal deformities. Group 2 deformities most often required combined anterior-posterior approaches with short constructs, and group 3 deformities most often required posterior-only approaches with 3-column osteotomies.

Progressive Adolescent Idiopathic Cervical Kyphosis Secondary to Constant Postural Neck Flexion Reading Habit with a 10-year Follow-up: Case Report and Literature Review

BACKGROUND

Although it has been established that adolescent idiopathic cervical kyphosis (AICK) has no known cause, there are associated risk factors. However, the underlying causes remain puzzling. This case report presents severe AICK linked to chronic neck flexion postural habit, treated with combined anterior and posterior correction surgery and review of the literature.

CASE PRESENTATION

A 16-year-old male with no history of trauma, surgery, or family history of spinal deformity complained of intolerable neck pain and rigidity. He developed an incessant reading of comic books at a very young age, and he preferred placing the book on the floor with his head flexed between his thighs. Acupuncture and massage therapy failed to relief symptoms. He had no neurological symptoms on examination and X-ray showed Cobb angle of 70.5°. MRI and CT scans showed no spinal cord compression or osteophyte formation. A combined anterior and posterior correction surgery was performed after a week of skull traction. The deformity was corrected, neck pain disappeared, and neck rotatory function maintained after posterior implant removal. The maximum follow-up was 10 years.

CONCLUSIONS

The potential underlying risk factor observed in this case is unusual. Chronic neck flexion postural habit is a potential risk factor of severe AICK in some individuals.

ACDF and posterior spinal fusion revision for posterior nonunion with deformity, myelopathy, and osteoporosis in an 87-year-old: A case report and literature review

Introduction

Cervical spondylotic myelopathy (CSM) is a spinal degenerative disorder that can ultimately lead to compression of the vertebral column with neurological sequelae. Although CSM is the most common spine pathology in the elderly American population, it remains a challenging disorder to treat among older patients.

Case presentation

We report an 86 year old female patient with CSM with a history of posterior cervical fusion attempt on C3-C6 that progressed to C3-C6 nonunion with loose instrumentation. The patient had severe osteoporosis. With these indications, the patient underwent a combined anterior-posterior decompression and fusion (CAPDF) consisting of anterior cervical discectomy and fusion (ACDF) of the C3-C5, corpectomy of C6 and C7 with off FDA label use of polymethyl methacrylate augmentation (PMMA) fixation of T1 screws anteriorly for C3-T1 plate fixation and second stage instrumented posterior spinal fusion (PSF) of C3-T3. The patient had a successful fusion and reduction of her cervical spine pain with preservation of her neurological status.

Discussion

We report this case of multi-stage combined anterior and posterior fusion as a corrective measure for pseudarthrosis of a prior posterior cervical spinal fusion attempt.

Conclusion

In the event of posterior spinal fusion instrumentation failure in patients with severe osteoporosis, combined multi-stage anterior-posterior fusion is a viable corrective intervention in octogenarians. This case also illustrated the utility of using PMMA for anterior cervical plate and screw stabilization in osteoporotic bone. The authors are not aware of the prior use of PMMA for screw fixation augmentation in the anterior cervical spine.

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Combined anterior-posterior cervical fusion for cervical spondylotic myelopathy and pseudarthrosis of prior intended fusion.

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Polymethylmethacrylate (PMMA) demonstrated as safe and effective for screw purchase augmentation in anterior cervical spine

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Multi stage spinal fusion to limit prolonged one-stage anesthesia identified to be safe and effective for this patient

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Management of cervical fusion pseudarthrosis in the setting of osteoporosis in the elderly

Instrumented Four-Level Anterior Cervical Discectomy and Fusion: Long-Term Clinical and Radiographic Outcomes

Background

There is a paucity of data on outcomes following four-level anterior cervical discectomy and fusions (ACDFs), especially the sagittal balance (SB) parameters.

Objective

We aimed to review the long-term clinical and radiographic outcomes for 41 consecutive patients that underwent instrumented four-level ACDF.

Materials and Methods

Records of 27 men and 14 women, aged 40-68 years, who underwent instrumented four-level ACDF and plating at C3-C7 (n = 37) or C4-T1 (n = 4) were retrospectively analyzed. Clinical outcomes that were assessed were the visual analog scale (VAS) for pain, neck disability index (NDI), Odom's criteria, improvement of symptoms, intraoperative and postoperative complications, SB, and need for revision surgery.

Results

The mean follow-up was 65 ± 36.3 months. The mean VAS for arm and neck pain significantly improved from 7.7 ± 1.4 to 3.5 ± 1.7 (P < 0.001). The NDI score significantly improved from 31 ± 8.2 to 19.3 ± 8.1 (P < 0.001). Concerning Odom's criteria, the grades were excellent (14), good (17), fair (9), and poor (1). Concerning intraoperative and postoperative complications, 10 cases developed dysphagia, 3 cases developed temporary dysphonia, 2 cases developed a postoperative hematoma, 1 patient developed C5 palsy, 1 vertebral artery (VA) injury, and 1 case had superficial infection. The average length of stay (LOS) was 2.9 ± 3.7 days. Three patients needed another surgery (one adjacent segment and two posterior foraminotomies). Regarding the mean change in SB parameters, Cobb's angle (CA) (C2-C7) was 14° ± 8.3°, fusion angle (FA) was 10.9 ± 10.9°, cervical straight vertical alignment (cSVA) was 0.6 ± 0.5 cm, T1 slope was 2.3° ± 3.4°, and disc height (DH) was 1.3 ± 0.9 mm.

Conclusion

Instrumented four-level ACDF is safe with a satisfactory outcome and supplementary posterior fusion was not required in any case.

A Comparative Analysis of Patients Undergoing Fusion for Adult Cervical Deformity by Approach Type

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To provide insight into postoperative complications, short-term quality outcomes, and costs of the surgical approaches of adult cervical deformity (ACD).

METHODS

A national database was queried from 2007 to 2016 to identify patients who underwent cervical fusion for ACD. Patients were stratified by approach type-anterior, posterior, or circumferential. Patients undergoing anterior and posterior approach surgeries were additionally compared using propensity score matching.

RESULTS

A total of 6575 patients underwent multilevel cervical fusion for ACD correction. Circumferential fusion had the highest postoperative complication rate (46.9% vs posterior: 36.7% vs anterior: 18.5%, P < .0001). Anterior fusion patients more commonly required reoperation compared with posterior fusion patients (P < .0001), and 90-day readmission rate was highest for patients undergoing circumferential fusion (P < .0001). After propensity score matching, the complication rate remained higher in the posterior, as compared to the anterior fusion group (P < .0001). Readmission rate also remained higher in the posterior fusion group; however, anterior fusion patients were more likely to require reoperation. At index hospitalization, posterior fusion led to 1.5× higher costs, and total payments at 90 days were 1.6× higher than their anterior fusion counterparts.

CONCLUSION

Patients who undergo posterior fusion for ACD have higher complication rates, readmission rates, and higher cost burden than patients who undergo anterior fusion; however, posterior correction of ACD is associated with a lower rate of reoperation.

Surgical Management of Pediatric Cervical Angular Kyphosis with 540° Approach and Metacarpal Plate: A Case Report and Introduction of a Novel Technique

Surgical decompression, deformity correction, and instrumentation of the upper cervical spine are challenging problems in cervical kyphosis, especially in infants and pediatrics. According to patients' age, surgical exposure is difficult and selecting the appropriate instrument for rigid fixation is crucial. In this article, we present a case of 2 years old with cervical angular kyphosis, which was approached posteriorly at first. Through posterior approach, C3–C5 laminectomy with complete excision of spinous process was performed. Then, the patient's position was changed to supine and C3–C5 corpectomies were performed anteriorly with a longitudinal incision, and the thecal sac was decompressed. A titanium cage with appropriate size and graft was placed after possible deformity correction conducted with head traction and neck extension. Anterior fixation was performed with two, 2-mm T-shaped metacarpal plates with two screws in C2 and four screws in C6. The patient's position was changed to prone again, and posterior fixation was done with two metacarpal plates located on lateral masses. We showed that a novel technique in correction and fixation of cervical kyphosis in pediatric is using metacarpal plates while they are fixed to lateral masses.

Risk factors for determining length of intensive care unit and hospital stays following correction of cervical deformity: evaluation of early severe adverse events

OBJECTIVE

Correction of rigid cervical deformities can be associated with high complication rates and result in prolonged intensive care unit (ICU) and hospital stays. In this study, the authors aimed to examine the risk factors contributing to length of stay (LOS) in both the hospital and ICU following adult cervical deformity (ACD) surgery and to identify severe adverse events that occurred in this setting.

METHODS

A retrospective review of ACD patients who underwent posterior-based osteotomies for deformity correction from 2010 to 2019 was performed. Inclusion criteria were cervical kyphosis > 20° and/or cervical sagittal vertical axis (cSVA) > 4 cm. Multivariate analysis was used to identify risk factors independently associated with ICU and hospital LOS.

RESULTS

A total of 107 patients were included. The mean age was 63.5 years, and 61.7% were female. Over half (52.3%) underwent 3-column osteotomies, while 47.7% underwent posterior column osteotomies. There was significant correction of all cervical parameters: cSVA (6.0 vs 3.6 cm, p < 0.001), cervical lordosis (8.2° vs -5.3°, p < 0.001), cervical scoliosis (6.5° vs 2.2°, p < 0.001), and T1-slope (40.2° vs 34.5°, p < 0.001). There were also reciprocal changes to the distal spine: thoracic kyphosis (54.4° vs 46.4°, p < 0.001), lumbar lordosis (49.9° vs 45.8°, p = 0.003), and thoracolumbar scoliosis (13.9° vs 11.1°, p = 0.009). Overall, 4 patients (3.7%) suffered aspiration-related complications, 3 patients (2.8%) experienced dysphagia requiring a feeding tube, and 4 patients (3.7%) had compromised airways, with 1 resulting in death. The mean ICU and hospital LOS were 2.8 days and 7.9 days, respectively. Multivariate analysis identified three factors independently associated with longer ICU LOS: female sex (3.0 vs 2.4 days, p = 0.004), ≥ 12 segments fused (3.5 vs 1.9 days, p = 0.002), and postoperative complication (4.0 vs 1.9 days, p = 0.017). These same factors were independently associated with longer hospital LOS as well: female sex (8.3 vs 7.3 days, p = 0.013), ≥ 12 segments fused (9.4 vs 6.2 days, p = 0.001), and complication (9.7 vs 6.7 days, p = 0.026).

CONCLUSIONS

Posterior-based osteotomies are very effective for the correction of ACD, but postoperative hospital stays are relatively longer than those following surgery for degenerative disease. Risk factors for prolonged ICU and hospital LOS consist of both nonmodifiable (female sex) and modifiable (≥ 12 segments fused and presence of complication) risk factors. Additional multicenter prospective studies will be needed to validate these findings.

Craniovertebral junction instability in Larsen syndrome: An institutional series and review of literature

Objective

Larsen syndrome (LS) is characterized by osteo-chondrodysplasia, multiple joint dislocations, and craniofacial abnormalities. Symptomatic myelopathy is attributed to C1-C2 instability and sub-axial cervical kyphosis. In this article, we have analyzed the surgical outcome after posterior fixation in LS with craniovertebral junction instability.

Methods

Ten symptomatic pediatric patients, operated between 2011 and 2019, were included, and the clinical outcome was assessed by Nurick grade, neurological improvement, and complications. The requirement of anti-spasticity drugs, the degree of bony fusion, and restriction of neck movement were also noted. At last follow-up, patient satisfaction score (PSS) and back to school status were studied. We also reviewed the literature and categorized two types of presentation of reported LS patients and discussed the pattern of disease progression among both.

Results

Ten patients, age range 1.5-16 years, underwent 12 surgeries (6 C1-C2 fixation, 4 long-segment posterior cervical fixation, and 2 trans-oral decompressions as the second stage); the mean follow-up was 23 (range, 6-86 months). All the ten patients in our study had the characteristic "dish-" like face and nine patients had acral anomalies. The median Nurick grade improved from preoperative (median = 4) to follow-up (median = 3). The requirement of anti-spasticity drugs decreased in seven patients and the neck-pain improved in nine patients. The median satisfaction at follow-up was good (median PSS = 2); five patients were going back to school.

Conclusion

Craniovertebral junction instability in LS is rare and surgically challenging. Early posterior fixation showed a promising outcome with a halt in the disease progression.

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.

Iatrogenic biological fracture of the cervical spine during gradual halo traction for kyphotic deformity correction: case report

Background

Severe kyphotic deformities carry high risk for neurological injuries as osteotomies are often required for correction. Surgeons often utilize a staged approach for dealing with these conditions starting with a period of halo traction to stretch tight soft tissues and partially correct the deformity, followed by surgery. Halo traction is a relatively safe procedure and complications are uncommon. We report a unique case of iatrogenic fracture of the cervical spine during gradual halo traction for deformity correction of a severe cervical kyphosis.

Case presentation

An 80-year-old female with previous cervical spine tuberculosis infection and C5-C6 anterior spinal fusion developed severe cervical kyphosis of 64° from C2-C6 and neck pain requiring deformity correction surgery. Gradual increase in traction weight was applied, aiming for a maximum traction weight of 45 pounds or half body weight. During the 1st stage halo-gravity traction, sudden neck pain and a loud cracking sound was witnessed during increase of the traction weight to 14 pounds. Imaging revealed a fracture through the C4 and reduction in kyphosis deformity to 11° from C2-C6. There was no neurological deficit. No further traction was applied and the patient underwent an in-situ occipital to T3 fusion without osteotomies. At 3-year follow-up, the patient was symptom-free and radiographs showed solid fusion and maintenance of alignment.

Conclusions

Iatrogenic fracture may occur with halo traction. Elderly patients with osteoporotic and diseased bone should be closely monitored during the treatment. A fracture without complications was a fortunate complication as the patient was able to avoid any high-risk osteotomies for deformity correction.

Level of evidence

IV

How Cervical Reconstruction Surgery Affects Global Spinal Alignment

BACKGROUND

There have been no reports describing how cervical reconstruction surgery affects global spinal alignment (GSA).

OBJECTIVE

To elucidate the effects of cervical reconstruction for GSA through a retrospective multicenter study.

METHODS

Seventy-eight patients who underwent cervical reconstruction surgery for cervical kyphosis were divided into a Head-balanced group (n = 42) and a Trunk-balanced group (n = 36) according to the values of the C7 plumb line (PL). We also divided the patients into a cervical sagittal balanced group (CSB group, n = 18) and a cervical sagittal imbalanced group (CSI group, n = 60) based on the C2 PL-C7 PL distance. Various sagittal Cobb angles and the sagittal vertical axes were measured before and after surgery.

RESULTS

Cervical alignment was improved to achieve occiput-trunk concordance (the distance between the center of gravity [COG] PL, which is considered the virtual gravity line of the entire body, and C7 PL < 30 mm) despite the location of COG PL and C7PL. A subsequent significant change in thoracolumbar alignment was observed in Head-balanced and CSI groups. However, no such significant change was observed in Trunk-balanced and CSB groups. We observed 1 case of transient and 1 case of residual neurological worsening.

CONCLUSION

The primary goal of cervical reconstruction surgery is to achieve occiput-trunk concordance. Once it is achieved, subsequent thoracolumbar alignment changes occur as needed to harmonize GSA. Cervical reconstruction can restore both cervical deformity and GSA. However, surgeons must consider the risks and benefits in such challenging cases.

Perioperative complications with multilevel anterior and posterior cervical decompression and fusion

OBJECTIVE

Cervical spondylotic myelopathy (CSM) is a progressive degenerative pathology that frequently affects older individuals and causes spinal cord compression with symptoms of neck pain, radiculopathy, and weakness. Anterior decompression and fusion is the primary intervention to prevent neurological deterioration; however, in severe cases, circumferential decompression and fusion is necessary. Published data regarding perioperative morbidity associated with these complex operations are scarce. In this study, the authors sought to add to this important body of literature by documenting a large single-surgeon experience of single-session circumferential cervical decompression and fusion.

METHODS

A retrospective analysis was performed to identify intended single-stage anterior-posterior or posterior-anterior-posterior cervical spine decompression and fusion surgeries performed by the primary surgeon (V.C.T.) at Rush University Medical Center between 2009 and 2016. Cases in which true anterior-posterior cervical decompression and fusion was not performed (i.e., those involving anterior-only, posterior-only, or delayed circumferential fusion) were excluded from analysis. Data including standard patient demographic information, comorbidities, previous surgeries, and intraoperative course, along with postoperative outcomes and complications, were collected and analyzed. Perioperative morbidity was recorded during the 90 days following surgery.

RESULTS

Seventy-two patients (29 male and 43 female, mean age 57.6 years) were included in the study. Fourteen patients (19.4%) were active smokers, and 56.9% had hypertension, the most common comorbidity. The most common clinical presentation was neck pain in 57 patients (79.2%). Twenty-three patients (31.9%) had myelopathy, and 32 patients (44.4%) had undergone prior cervical spine surgery. Average blood loss was 613 ml. Injury to the vertebral artery was encountered in 1 patient (1.4%). Recurrent laryngeal nerve palsy was observed in 2 patients (2.8%). Two patients (2.8%) had transient unilateral hand grip weakness. There were no permanent neurological deficits. Dysphagia was encountered in 45 patients (62.5%) postoperatively, with 23 (32%) requiring nasogastric parenteral nutrition and 9 (12.5%) patients ultimately undergoing percutaneous endoscopic gastrostomy (PEG) placement. Nine of the 72 patients required a tracheostomy. The incidence of pneumonia was 6.9% (5 patients) overall, and 2 of these patients were in the tracheostomy group. Superficial wound infections occurred in 4 patients (5.6%). Perioperative death occurred in 1 patient. Reoperation was necessary in 10 patients (13.9%). Major perioperative complications (permanent neurological deficit, vascular injury, tracheostomy, PEG tube, stroke, or death) occurred in 30.6% of patients. The risk of minor perioperative complications (temporary deficit, dysphagia, deep vein thrombosis, pulmonary embolism, urinary tract infection, pneumonia, or wound infection) was 80.6%.

CONCLUSIONS

Single-session anterior-posterior cervical decompression and fusion is an inherently morbid operation required in select patients with cervical spondylotic myelopathy. In this large single-surgeon series, there was a major perioperative complication risk of 30.6% and minor perioperative complication risk of 80.6%. This overall elevated risk for postoperative complications must be carefully considered and discussed with the patient preoperatively. In some situations, shared decision making may lead to the conclusion that a procedure of lesser magnitude may be more appropriate.

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.

Adult cervical deformity: radiographic and osteotomy classifications

Cervical spine deformity represents a broad spectrum of pathologies that are both complex in etiology and debilitating towards quality of life for patients. Despite advances in the understanding of drivers and outcomes of cervical spine deformity, only one classification system and one system of nomenclature for osteotomy techniques currently exist. Moreover, there is a lack of standardization regarding the indications for each technique. This article reviews the adult cervical deformity (ACD) and current classification and nomenclature for osteotomy techniques, highlighting the need for further work to develop a unified approach for each case and improve communication amongst the spine community with respect to ACD.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Early and Midterm Outcomes of Surgical Correction for Severe Dystrophic Cervical Kyphosis in Patients with Neurofibromatosis Type 1: A Retrospective Multicenter Study

OBJECTIVE

To evaluate the early and midterm outcomes of surgical correction for severe dystrophic cervical kyphosis in patients with neurofibromatosis type 1 (NF-1) and analyze the pathomechanics and the influence on surgical efficacy of related systemic skeletal dystrophy.

METHODS

Ten patients who underwent surgical correction for NF-1-related severe dystrophic cervical kyphosis were reviewed. Radiographic parameters, including local and global Cobb angle, sagittal vertical axis, and T-1 slope, were measured. The visual analog scale score, Japanese Orthopaedic Association score, Neck Disability Index, Patient Satisfaction Index, and complications were evaluated.

RESULTS

The average follow-up was 50.6 months. The local and global Cobb angle improved from the preoperative average of 82.0° and 54.9° to an average of 35.6° and 29.8°, respectively, at the time of final follow-up. The C2-7 sagittal vertical axis averaged 5.8 mm before surgery and 8.9 mm at the final follow-up. The average T1 slope was -12.3° before surgery and -1.6° at the final follow-up. The visual analog scale score, Japanese Orthopaedic Association score, and Neck Disability Index improved significantly, and the overall satisfaction rate was 90.0%. One death and 4 instrumentation failures occurred, 3 patients showed progression of the kyphosis, and 2 fusion failures were observed.

CONCLUSIONS

Surgical correction, specifically the combined anteroposterior procedure, is essential and effective for management of NF-1-related severe dystrophic cervical kyphosis. However, high incidences of instrumentation failure, kyphosis progression, and fusion failure were observed. NF-1-related continuous skeletal dystrophy caused by multiple metabolic factors remarkably affected the midterm outcomes. Early prevention and targeted pharmacotherapy may be necessary.

Characteristics of deformity surgery in patients with severe and rigid cervical kyphosis (CK): results of the CSRS-Europe multi-centre study project

INTRODUCTION AND PURPOSE

Little information exists on surgical characteristics, complications and outcomes with corrective surgery for rigid cervical kyphosis (CK). To collate the experience of international experts, the CSRS-Europe initiated an international multi-centre retrospective study.

METHODS

Included were patients at all ages with rigid CK. Surgical and patient specific characteristics, complications and outcomes were studied. Radiographic assessment included global and regional sagittal parameters. Cervical sagittal balance was stratified according to the CSRS-Europe classification of sagittal cervical balance (types A-D).

RESULTS

Eighty-eight patients with average age of 58 years were included. CK etiology was ankylosing spondlitis (n = 34), iatrogenic (n = 25), degenerative (n = 9), syndromatic (n = 6), neuromuscular (n = 4), traumatic (n = 5), and RA (n = 5). Blood loss averaged 957 ml and the osteotomy grade 4.CK-correction and blood loss increased with osteotomy grade (r = 0.4/0.6, p < .01). Patients with different preop sagittal balance types had different approaches, preop deformity parameters and postop alignment changes (e.g. C7-slope, C2-7 SVA, translation). Correction of the regional kyphosis angle (RKA) was average 34° (p < .01). CK-correction was increased in patients with osteoporosis and osteoporotic vertebrae (POV, p = .006). 22% of patients experienced a major long-term complication and 14% needed revision surgery. Patients with complications had larger preop RKA (p = .01), RKA-change (p = .005), and postop increase in distal junctional kyphosis angle (p = .02). The POV-Group more often experienced postop complications (p < .0001) and revision surgery (p = .02). Patients with revision surgery had a larger RKA-change (p = .003) and postop translation (p = .04). 21% of patients had a postop segmental motor deficit and the risk was elevated in the POV-Group (p = .001).

CONCLUSIONS

Preop patient specific, radiographic and surgical variables had a significant bearing on alignment changes, outcomes and complication occurrence in the treatment of rigid CK.

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.

Cervical Spine Osteomyelitis: A Systematic Review of Instrumented Fusion in the Modern Era

OBJECTIVE

For cases of cervical osteomyelitis that require surgery, concern has continued regarding instrumentation owing to the potential for bacterial seeding of the hardware. We performed a systematic review of the current data.

METHODS

A search was performed using Medline, Embase, and Ovid for articles using the keywords "cervical osteomyelitis/spondylodiscitis" and "fusion" or "instrumentation" reported from 1980 to 2017. Prospective or retrospective studies describing ≥2 patients with cervical osteomyelitis were included in the analysis; non-English reports were excluded. Individual patients were excluded from the final analysis if they had previously undergone spinal instrumentation.

RESULTS

A total of 239 patients from 24 studies met our criteria. Surgical approaches were classified as anterior-only, combined anteroposterior, and posterior-only for 64.8%, 31.9%, and 3.3% of the patients respectively. Of the patients treated using an anterior-only approach, 76.5% had received anterior plating and 85.3%, a cage or spacer implants. Of the patients who had undergone combined approaches, 85.1% underwent circumferential fixation and 14.9%, anterior debridement with posterior instrumentation. The follow-up period ranged from 6 weeks to 11 years (mean, 31.0 months). All the studies reporting the fusion rates, except for 1, reported a 100% fusion rate. The reported rates of pain improvement and neurologic recovery were favorable. The incidence of hardware failure and wound complications was 4.6% and 4.0%, respectively.

CONCLUSIONS

Despite placing instrumentation during active infection, the rates of hardware failure and wound complications were comparable to those of elective cervical spine procedures. These results suggest that surgical intervention with instrumentation is a safe treatment option for patients with cervical spine osteomyelitis.

One-Stage Wedge Osteotomy Through Posterolateral Approach for Cervical Postlaminectomy Kyphosis with Anterior Fusion

OBJECTIVE

Osteotomy through anterior exposure is challenging with severe complications for upper cervical kyphosis (CK), especially for cases with previous anterior fusion. A novel technique comprising 1-stage osteotomy via a posterolateral-only approach is introduced for treatment of CK secondary to C2-4 laminectomy for neurofibroma removal and subsequent anterior fusion.

METHODS

A 42-year-old man presented with progressive numbness and weakness of upper and lower limbs. As an adolescent, he underwent posterior laminectomy and neurofibroma excision without effective fixation and anterior C2-4 vertebra fusion 6 years later. Sagittal computed tomography indicated that Cobb angle between C2 and C6 was 68° with complete fusion between C2 and C4 vertebral bodies. Secondary CK was diagnosed based on medical history and radiographic findings, and modified Japanese Orthopaedic Association scale score was 10. Piezosurgery was used for osteotomy by shortening the vertebral height through posterolateral approach after cervical pedicle screw placement. Occipitocervical fusion was performed with compression between C2 and C4.

RESULTS

Cobb angle was adjusted to 8° postoperatively. Modified Japanese Orthopaedic Association score increased to 14 with obvious muscle strength improvement. The 6-month postoperative x-ray indicated good position of C2-4 vertebrae and occipitocervical fixation system. No neurologic complications or local recurrence was found at final follow-up at 8 months. The patient returned to work in his full capacity.

CONCLUSIONS

Preliminary outcomes reveal wedge osteotomy via piezosurgery through a posterolateral-only approach is feasible and effective in revision surgery for upper CK with previous anterior fusion.

Two-level cervical corpectomy-long-term follow-up reveals the high rate of material failure in patients, who received an anterior approach only

In contrast to a one-level cervical corpectomy, a multilevel corpectomy without posterior fusion is accompanied by a high material failure rate. So far, the adequate surgical technique for patients, who receive a two-level corpectomy, remains to be elucidated. The aim of this study was to determine the long-term clinical outcome of patients with cervical myelopathy, who underwent a two-level corpectomy. Outcome parameters of 21 patients, who received a two-level cervical corpectomy, were retrospectively analyzed concerning reoperations and outcome scores (VAS, Neck Disability Index (NDI), Nurick scale, modified Japanese Orthopaedic Association score (mJOAS), Short Form 36-item Health Survey Questionnaire (SF-36)). The failure rate was determined using postoperative radiographs. The choice over the surgical procedures was exercised by every surgeon individually. Therefore, a distinction between two groups was possible: (1) anterior group (ANT group) with a two-level corpectomy and a cervical plate, (2) anterior/posterior group (A/P group) with two-level corpectomy, cervical plate, and additional posterior fusion. Both groups benefitted from surgery concerning pain, disability, and myelopathy. While all patients of the A/P group showed no postoperative instability, one third of the patients of the ANT group exhibited instability and clinical deterioration. Thus, a revision surgery with secondary posterior fusion was needed. Furthermore, the ANT group had worse myelopathy scores (mJOAS_{ANT group} = 13.5 ± 2.5, mJOAS_{A/P group} = 15.7 ± 2.2). Patients with myelopathy, who receive a two-level cervical corpectomy, benefitted from surgical decompression. However, patients with a sole anterior approach demonstrated a very high rate of instability (33%) and clinical deterioration in a long-term follow-up. Therefore, we recommend to routinely perform an additional posterior fusion after two-level cervical corpectomy.

[Normal sagittal profile of the cervical spine - must the cervical spine always be lordotic?]

BACKGROUND

The cervical spine is very complex, and it allows the largest range of motion relative to the rest of the spine. The fundamental function of the cervical spine is to maintain the head balanced over the trunk and to maintain horizontal gaze. The cervical spine must be both stable and flexible to guarantee function. Changes of the sagittal profile of the cervical spine may affect function and quality of life. The relationship between full body alignment and maintaining gaze necessitates a thorough understanding of the cranio-spino-pelvic alignment as a component of balance.

QUESTION

Now the question is, what kind of sagittal profile does the cervical spine need for proper function? In the literature, normal sagittal alignment of the cervical spine is controversial. In general, there is the assumption that the alignment is lordotic. Does the data in the literature support this?

RESULTS

The present literature review supports the following facts: Ideal cervical spine alignment is mostly lordotic, but not always; ideal cervical spine alignment can be lordotic, neutral or kyphotic; ideal cervical spine alignment is driven by the necessity of supporting the head and maintaining horizontal gaze; the cervical spine is in harmony with regional alignment (thoracic kyphosis) and sagittal global alignment (SVA): TK (↑) → T1 Slope (↑) → CL (↑), TK (↓) → T1 Slope (↓) → CL (↓), SVA >50 mm: the cervical curve should be lordotic to maintain horizontal gaze, SVA <0 mm: the cervical curve should be kyphotic to maintain horizontal gaze.

[Intraoperative neuromonitoring in cervical deformity surgery]

Correction of cervical deformity is associated with a considerable risk of neurological deterioration. The use of intraoperative neuromonitoring (IOM) can, however, significantly increase patient safety. Nonetheless, data on the effectiveness of IOM during reconstructive cervical surgery are very limited. Since the surgical maneuvers in reconstructive cervical surgery represent the same dangers to the spinal cord as in scoliosis correction, the same influence of IOM on the clinical outcome may be assumed. IOM has been shown to decrease the rate of neurological complications in scoliosis surgery. Herein, we discuss the current evidence for the efficacy of IOM during reconstructive cervical surgery as well as during scoliosis surgery.

Preventing Construct Subsidence Following Cervical Corpectomy: The Bump-stop Technique

Cervical corpectomy is a viable technique for the treatment of multilevel cervical spine pathology. Despite multiple advances in both surgical technique and implant technology, the rate of construct subsidence can range from 6% for single-level procedures to 71% for multilevel procedures. In this technical note, we describe a novel technique, the bump-stop technique, for cervical corpectomy. The technique positions the superior and inferior screw holes such that the vertebral bodies bisect them. This allows for fixation in the dense cortical bone of the endplate while providing a buttress to corpectomy cage subsidence. We then discuss a retrospective case review of 24 consecutive patients, who were treated using this approach, demonstrating a lower than previously reported cage subsidence rate.

Osteotomies in ankylosing spondylitis: where, how many, and how much?

INTRODUCTION

This article presents the current concepts of correction of spinal deformity in ankylosing spondylitis (AS) patients. Untreated AS can be a debilitating disease. In a few patients, disease progression results in severe spinal deformity affecting not only the thoracolumbar, but also the cervical spine. Surgery for correction in AS patients has a long history. With the advent of modern instrumentation, standardization of surgical and anesthesiologic techniques, surgical safety and corrective results could be improved and experiences from lumbar osteotomies could be transferred to the cervical spine.

METHODS

This article presents the current concepts of correction of spinal deformity in AS patients. In particular, questions regarding the localization and number of osteotomies, the optimal surgical target angle as well as planning and prediction of postoperative alignment are discussed.

RESULTS

Insight into recent technical developments, current challenges with correction and geometric analysis of center of rotation (COR) in cervical 3-column osteotomies (3CO) will be presented.

CONCLUSION

The article should encourage readers to improve surgical correction efficacy and provide a better understanding of correction geometry in 3CO for thoracolumbar and cervical spinal deformities.

T-1 pedicle subtraction osteotomy for the treatment of rigid cervical kyphotic deformity: report of 4 cases

Cervical kyphotic deformity represents a difficult to treat pathology often arising from multiple factors including, but not limited to, traumatic injuries, degenerative changes, and ankylosing spondylitis. Furthermore, treatment of these deformities becomes increasingly difficult with any preexisting instrumentation. Currently, several options exist to treat these severe deformities, with the Smith-Petersen osteotomy and C-7 pedicle subtraction osteotomy being the most frequently used approaches. However, these techniques come with significant risk to the patient including nerve root injury as well as compression of the vertebral arteries. The authors here report on a series of 4 patients with rigid cervical deformity who underwent T-1 pedicle subtraction osteotomy. The authors review the relevant literature and provide a novel, less risky, and potentially more corrective approach for treating cervical deformities.

Global Spinal Alignment in Cervical Kyphotic Deformity: The Importance of Head Position and Thoracolumbar Alignment in the Compensatory Mechanism

BACKGROUND

Previous studies have evaluated cervical kyphosis (C-kypho) using cervical curvature or chin-brow vertical angle, but the relationship between C-kypho and global spinal alignment is currently unknown.

OBJECTIVE

To elucidate global spinal alignment and compensatory mechanisms in primary symptomatic C-kypho using full-spine radiography.

METHODS

In this retrospective multicenter study, symptomatic primary C-kypho patients (Cerv group; n = 103) and adult thoracolumbar deformity patients (TL group; n = 119) were compared. We subanalyzed Cerv subgroups according to sagittal vertical axis (SVA) values of C7 (SVAC7 positive or negative [C7P or C7N]). Various Cobb angles (°) and SVAs (mm) were evaluated.

RESULTS

SVAC7 values were –20.2 and 63.6 mm in the Cerv group and TL group, respectively (P &lt; .0001). Various statistically significant compensatory curvatures were observed in the Cerv group, namely larger lumbar lordosis (LL) and thoracic kyphosis. The C7N group had significantly lower SVACOG (center of gravity of the head) and SVAC7 (32.9 and –49.5 mm) values than the C7P group (115.9 and 45.1 mm). Sagittal curvatures were also different in T4-12, T10-L2, LL4-S, and LL. The value of pelvic incidence (PI)-LL was different (C7N vs C7P; –2.2° vs 9.9°; P &lt; .0003). Compensatory sagittal curvatures were associated with potential for shifting of SVAC7 posteriorly to adjust head position. PI-LL affected these compensatory mechanisms.

CONCLUSION

Compensation in symptomatic primary C-kypho was via posterior shifting of SVAC7, small T1 slope, and large LL. However, even in C-kypho patients, lumbar degeneration might affect global spinal alignment. Thus, global spinal alignment with cervical kyphosis is characterized as head balanced or trunk balanced.

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

OBJECTIVE

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

SUMMARY OF BACKGROUND DATA

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

An in vitro evaluation of sagittal alignment in the cervical spine after insertion of supraphysiologic lordotic implants

PURPOSE

Cervical spine malalignment can develop as a consequence of degenerative disc disease or following spinal surgery. When normal sagittal alignment of the spine is disrupted, further degeneration may occur adjacent to the deformity. The purpose of this study was to investigate changes in lordosis and sagittal alignment in the cervical spine after insertion of supraphysiologic lordotic implants.

METHODS

Eight cadaveric cervical spines (Occiput-T1) were tested. The occiput was free to translate horizontally and vertically but constrained from angular rotation. The T1 vertebra was rigidly fixed with a T1 tilt of 23°. Implants with varying degrees of lordosis were inserted starting with single-level constructs (C5-C6), followed by two (C5-C7), and three-level (C4-C7) constructs. Changes in sagittal alignment, Occ-C2 angle, cervical lordosis (C2-7), and segmental lordosis were measured.

RESULTS

Increasing cage lordosis led to global increases in cervical lordosis. As implanted segmental lordosis increased, the axial levels compensated by decreasing in lordosis to maintain horizontal gaze. An increase in cage lordosis also corresponded with larger changes in SVA.

CONCLUSION

Reciprocal compensation was observed in the axial and sub-axial cervical spine, with the Occ-C2 segment undergoing the largest compensation. Adding more implant lordosis led to larger reciprocal changes and changes in SVA. Implants with supraphysiologic lordosis may allow for additional capabilities in correcting cervical sagittal plane deformity, following further clinical evaluation.

Complications and Outcomes for Surgical Approaches to Cervical Kyphosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The primary objective of this study is to report the safety and efficacy of the different surgical approaches to cervical deformity correction surgery.

SUMMARY OF BACKGROUND DATA

Cervical subaxial deformity surgery has been shown to be an effective means to alleviate pain and improve neurological function in symptomatic patients. The reported outcomes and complications for the different surgical approaches (ventral, dorsal, and combined) are limited to small retrospective studies. The appropriate surgical approach is at times unclear, which is likely attributed to the overlap in indications for the ventral and combined approach.

MATERIALS AND METHODS

A retrospective review of 76 patients who underwent cervical deformity surgery for cervical kyphosis at 1 institution was performed. The authors reviewed the complications, radiographic outcomes, and long-term functional outcomes for all patients.

RESULTS

The majority of patients in all groups reported excellent (15%) or good (50%) outcomes, with a mean improvement in modified Japanese orthopedic association score of 1.3. There were 26 perioperative complications (34%) for 19 patients (25%). We found the ventral-alone and combined approaches to achieve similar degrees of correction (23.1 and 23.2 degrees, respectively). The combined approach had the highest complication rate of the 3 approaches (combined: 40%, ventral: 30%, dorsal: 27%). The dorsal, ventral, and combined approaches had a mean neurological improvement in modified Japanese orthopedic association scores of 1.95, 3.00, and 1.26, respectively, and mean pain improvement of 0.8, 2.0, and 1.4.

CONCLUSIONS

Given the moderate improvements in long-term outcomes, and the risks for perioperative complications, we recommend a careful selection process for patients eligible for cervical deformity surgery. We found that the ventral approach has reduced complications, similar degree of correction capability, and potentially higher improved neurological outcomes compared to the combined approach.

Accuracy of 3D fluoroscopy-navigated anterior transpedicular screw insertion in the cervical spine: an experimental study

PURPOSE

The technique of pedicle screw stabilization is finding increasing popularity for use in the cervical spine. Implementing anterior transpedicular screws (ATPS) in cervical spine offers theoretical advantages compared to posterior stabilization. The goal of the current study was the development of a new setting for navigated insertion of ATPS, combining the advantage of reduced invasiveness of an anterior approach with the technical advantages of navigation.

METHODS

20 screws were implanted in levels C3 to C6 of four cervical spine models (SAWBONES(®) Cervical Vertebrae with Anterior Ligament) with the use of 3D fluoroscopy navigation system [Arcadis Orbic 3D, Siemens and VectorVision fluoro 3D trauma software (BrainLAB)]. The accuracy of inserted screws was analyzed according to postoperative CT scans and following the modified Gertzbein and Robbins classification.

RESULTS

20 anterior pedicle screws were placed in four human cervical spine models. Of these, eight screws were placed in C3, two screws in C4, six screws in C5, and four screws in C6. 16 of 20 screws (80 %) reached a grade 1 level of accuracy according to the modified Gertzbein and Robbins Classification. Three screws (15 %) were grade 2, and one screw (5 %) was grade 3. Grade 4 and 5 positions were not evident. Summing grades 1 and 2 together as "good" positions, 95 % of the screws achieved this level. Only a single screw did not fulfill these criteria.

CONCLUSION

The setting introduced in this study for navigated insertion of ATPS into cervical spine bone models is well implemented and shows excellent results, with an accuracy of 95 % (Gertzbein and Robbins grade 2 or better). Thus, this preliminary study represents a prelude to larger studies with larger case numbers on human specimens.

Pedicle Reduction Osteotomy in the Upper Cervical Spine: Technique, Case Report and Review of the Literature

OBJECTIVE

To present a case report of the correction of a degenerative cervical 45-degree kyphosis centered at C4 with a single stage PSO.

SUMMARY OF BACKGROUND DATA

Correction of a fixed cervical kyphosis is a surgical challenge that is frequently managed with a combination of anterior and posterior surgical procedures. An alternative the three stage operation is a single stage pedicle subtraction osteotomy (PSO). A PSO releases the posterior, middle and anterior columns of the spine by resecting the facet joints, pedicles, and a portion of the vertebral body at the apex of a kyphosis through a posterior approach.

METHODS

This was a case report of a patient who had degenerative cervical 45 degree kyphosis and was corrected with a single stage pedicle subtraction osteotomy. We did a literature review to provide information on current techniques to treat these patients.

RESULTS

With careful resection of the lateral mass and decompression of the vertebral artery by removal of the posterior margin of the foramen transversarium the upper cervical pedicles can be accessed and a PSO can be performed. The vertebral arteries were not obstructed or kinked with posterior reduction of the PSO in this case.

CONCLUSIONS

A closing wedge PSO is a useful tool for correcting fixed kyphotic deformities in the upper cervical spine. Further studies are necessary to evaluate the long-term outcomes in these patients.

Bilateral Pedicle and Crossed Translaminar Screws in C2

Multiple techniques exist for the fixation of C2, including axial pedicle screws and bilateral translaminar screws. We describe a novel method of incorporating both the translaminar and pedicle screws within C2 to improve fixation to the subaxial spine in patients requiring posterior cervical instrumentation for deformity correction or instability. We report three cases of patients with cervical spinal instability, who underwent cervical spine instrumentation for stabilization and/or deformity correction. Bilateral C2 pedicle screws were inserted, followed by bilateral crossed laminar screws. The instrumentation method successfully achieved fixation in all three patients. There were no immediate postoperative complications, and hardware positioning was satisfactory. Instrumenting C2 with translaminar and pedicle screws is technically feasible, and it may improve fixation to the subaxial spine in patients with poor bone quality or severe subaxial deformity, which require a stronger instrumentation construct.

A controlled anterior sequential interbody dilation technique for correction of cervical kyphosis

OBJECT

Cervical kyphosis can lead to spinal instability, spinal cord injury, and disability. The correction of cervical kyphosis is technically challenging, especially in severe cases. The authors describe the anterior sequential interbody dilation technique for the treatment of cervical kyphosis and evaluate perioperative outcomes, degree of correction, and long-term follow-up outcomes associated with the technique.

METHODS

In the period from 2006 to 2011, a consecutive cohort of adults with cervical kyphosis (Cobb angles ≥ 0°) underwent sequential interbody dilation, a technique entailing incrementally increased interbody distraction with the sequential placement of larger spacers (at least 1 mm) in the discectomy and/or corpectomy spaces. The authors retrospectively reviewed these patients, and primary outcomes of interest included kyphosis correction, blood loss, hospital stay, complications, Nurick grade, pain, reoperation, and pseudarthrosis. A subgroup analysis among patients with preoperative kyphosis of 0°–9° (mild), 10°–19° (moderate), and ≥ 20° (severe) was performed.

RESULTS

One hundred patients were included in the study: 74 with mild preoperative cervical kyphosis, 19 with moderate, and 7 with severe. The mean patient age was 53.1 years, and 54.0% of the patients were male. Mean estimated blood loss was 305.6 ml, and the mean length of hospital stay was 5.2 days. The overall complication rate was 9.0%, and there were no deaths. Sixteen percent of patients underwent supplemental posterior fusion. There was significant correction in cervical alignment (p < 0.001), and the mean overall kyphosis correction was 12.4°. Patients with severe preoperative kyphosis gained a correction of 24.7°, those with moderate kyphosis gained 17.8°, and those with mild kyphosis gained 10.1°. A mean correction of 32.0° was obtained if 5 levels were addressed. The mean follow-up was 26.8 months. The reoperation rate was 4.7%. At follow-up, there was significant improvement in visual analog scale neck pain (p = 0.020) and Nurick grade (p = 0.037). The pseudarthrosis rate was 6.3%.

CONCLUSIONS

Sequential interbody dilation is a feasible and effective method of correcting cervical kyphosis. Complications and reoperation rates are low. Similar benefits are seen among all severities of kyphosis, and greater correction can be achieved in more severe cases.

Single-stage Anterior and Posterior Fusion Surgery for Correction of Cervical Kyphotic Deformity Using Intervertebral Cages and Cervical Lateral Mass Screws: Postoperative Changes in Total Spine Sagittal Alignment in Three Cases with a Minimum Follow-up of Five Years

The surgical treatment of cervical kyphotic deformity remains challenging. As a surgical method that is safer and avoids major complications, the authors present a procedure of single-stage anterior and posterior fusion to correct cervical kyphosis using anterior interbody fusion cages without plating, as illustrated by three consecutive cases. Case 1 was a 78-year-old woman who presented with a dropped head caused by degeneration of her cervical spine. Case 2 was a 54-year-old woman with athetoid cerebral palsy. She presented with cervical myelopathy and cervical kyphosis. Case 3 was a 71-year-old woman with cervical kyphotic deformity following a laminectomy. All three patients underwent anterior release and interbody fusion with cages and posterior fusion with cervical lateral mass screw (LMS) fixation. Postoperative radiographs showed that correction of kyphosis was 39° in case 1, 43° in case 2, and 39° in case 3. In all three cases, improvement of symptoms was established without major perioperative complications, solid fusion was achieved, and no loss of correction was observed at a minimum follow-up of 61 months. We also report that preoperative total spine sagittal malalignment was improved after corrective surgery for cervical kyphosis and was maintained at the latest follow-up in all three cases. The combination of anterior fusion cages and LMS is considered a safe and effective procedure in cases of severe cervical kyphotic deformity. Preoperative total spine sagittal malalignment improved, accompanied by correction of cervical kyphosis, and was maintained at last follow-up in all three cases.

Accuracy of fluoroscopy versus computer-assisted navigation for the placement of anterior cervical pedicle screws

STUDY DESIGN

Randomized laboratory cadaver study.

OBJECTIVE

The objective of this study was to determine the accuracy of anterior transpedicular screw placement in the cervical spine using conventional fluoroscopy versus computer-assisted navigation.

SUMMARY OF BACKGROUND DATA

Traditionally, global cervical instability has required anterior and posterior fixation due to the superior biomechanical stability of circumferential constructs. Anterior transpedicular screws (ATPS) have recently been advocated as a single surgical approach. Current clinical publications report using fluoroscopic guidance for screw placement. Computer-assisted navigation (CAN) systems have demonstrated enhanced accuracy of pedicle screw placement at all spine levels but have not been assessed for ATPS.

METHODS

The anterior vertebrae of 9 fresh frozen cadaver cervical spines were exposed, preserving the lateral and posterior soft tissue envelope. Nine practicing spine surgeons placed 2.0-mm titanium anterior transpecidular Kirschner wires into the C3-T1 pedicles bilaterally using fluoroscopy or CAN guidance. Specimens were imaged by computed tomography and virtual screws were overlaid on the K-wires. Targeting accuracy was compared between the 2 techniques in all planes using a 5-level grading scale.

RESULTS

The percentage of acceptable screw placements for fluoroscopy and CAN was 42.6% and 66.7%, respectively (P = 0.012). Catastrophic screw placement (grade 3 or 4) was 33.3% for fluoroscopy and 16.7% for CAN. In the multivariable model, the accuracy rate was 67% lower for fluoroscopy than for CAN after controlling for other factors (odds ratio: 0.33, 95% confidence interval: 0.14-0.79).

CONCLUSION

The accuracy of CAN-guided placement of K-wires for ATPS was superior to placement under fluoroscopic guidance, demonstrating statistically more acceptable screw placements and significantly less catastrophic virtual screws. However, malposition was still high, with potential for vertebral artery and neurological injury in a clinical setting. Further advancement in current ATPS techniques is warranted prior to widespread implementation in a patient setting.

LEVEL OF EVIDENCE

N/A.

Perioperative morbidity and mortality comparison in circumferential cervical fusion for osteomyelitis versus cervical spondylotic myelopathy

OBJECT

The most common indications for circumferential cervical decompression and fusion are cervical spondylotic myelopathy (CSM) and cervical osteomyelitis (COM). Currently, the informed consent process prior to circumferential cervical fusion surgery is not different for these two groups of patients, as details of their diagnosis-specific risk profiles have not been quantified. The authors compared two patient cohorts with either CSM or COM treated using circumferential fusion. They sought to quantify perioperative morbidity and postoperative mortality in these two groups to assist with a diagnosis-specific informed consent process for future patients undergoing this type of surgery.

METHODS

Perioperative and follow-up data from two cohorts of patients who had undergone circumferential cervical decompression and fusion were analyzed. Estimated blood loss (EBL), length of stay (LOS), perioperative complications, hospital readmission, 30-day reoperation rates, change in Nurick grade, and mortality were compared between the two groups.

RESULTS

Twenty-two patients were in the COM cohort, and 24 were in the CSM cohort. Complications, hospital readmission, 30-day reoperation rates, EBL, and mortality were not statistically different, although patients with COM trended higher in each of these categories. There was a significantly greater LOS (p < 0.001) in the COM group and greater improvement in Nurick grade in the CSM group (p < 0.001).

CONCLUSIONS

When advising patients undergoing circumferential fusion about perioperative risk factors, it is important for those with COM to know that they are likely to have a higher rate of complications and mortality than those with CSM who are undergoing similar surgery. Furthermore, COM patients have less neurological improvement than CSM patients after surgery. This information may be useful to surgeons and patients in providing appropriate informed consent during preoperative planning.

An algorithmic strategy for selecting a surgical approach in cervical deformity correction

Adult degenerative cervical kyphosis is a debilitating disease that often requires complex surgical management. Young spine surgeons, residents, and fellows are often confused as to which surgical approach to choose due to lack of experience, absence of a systematic method of surgical management, and today's plethora of information regarding surgical techniques. Although surgeons may be able to perform anterior, posterior, or combined (360°) approaches to the cervical spine, many struggle to rationally choose an appropriate approach for deformity correction. The authors introduce an algorithm based on morphology and pathology of adult cervical kyphosis to help the surgeon select the appropriate approach when performing cervical deformity surgery. Cervical deformities are categorized into 5 different prevalent morphological types encountered in clinical settings. A surgical approach tailored to each category/type of deformity is then discussed, with a concrete case illustration provided for each. Preoperative assessment of kyphosis, determination of the goal for surgery, and the complications associated with cervical deformity correction are also summarized. This article's goal is to assist with understanding the big picture for surgical management in cervical spinal deformity.

Traumatic, high-cervical, coronal-plane spondyloptosis with unilateral vertebral artery occlusion: treatment using a prophylactic arterial bypass graft, open reduction, and instrumented segmental fusion

The authors present a case of traumatic, complete, high cervical spine injury in a patient with gradual worsening deformity and neck pain while in rigid cervical collar immobilization, ultimately resulting in coronal-plane spondyloptosis. Due to the extent of lateral displacement of the spinal elements, preoperative evaluation included catheter angiography, which revealed complete right vertebral artery (VA) occlusion. A prophylactic arterial bypass graft from the right occipital artery to the extradural right VA was fashioned to augment posterior circulation blood supply prior to reduction and circumferential instrumented fusion. Following surgery, the patient was able to participate in an aggressive rehabilitation program allowing early mobilization, and he ceased to be ventilator-dependent following implantation of a diaphragmatic pacer. The authors review factors leading to progression of this type of injury and suggest technical pearls as well as highlight specific management pitfalls, including operative risks.