Operative treatment outcomes for adult cervical deformity: a prospective multicenter assessment with mean 3-year follow-up

Elias Elias Department of Neurosurgery, University of Virginia, Charlottesville, Virginia;

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Shay Bess Presbyterian St. Luke’s Medical Center, Denver, Colorado;

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Breton G. Line Presbyterian St. Luke’s Medical Center, Denver, Colorado;

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Virginie Lafage Department of Orthopedic Surgery, Lennox Hill Hospital, New York, New York;

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Renaud Lafage Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York;

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Eric Klineberg Department of Orthopaedic Surgery, University of California, Davis, Sacramento, California;

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Han Jo Kim Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York;

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Peter Passias Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, New York;

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Zeina Nasser Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Hadath, Lebanon;

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Jeffrey L. Gum Leatherman Spine Center, Louisville, Kentucky;

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Khaled Kebaish Department of Orthopedic Surgery, Johns Hopkins Hospital, Baltimore, Maryland;

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Robert Eastlack Scripps Clinic, San Diego, California;

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Alan H. Daniels Department of Orthopedic Surgery, Brown University, Providence, Rhode Island;

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Gregory Mundis Jr. Scripps Clinic, San Diego, California;

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Richard Hostin Department of Orthopaedic Surgery, Baylor Scoliosis Center, Plano, Texas;

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Themistocles S. Protopsaltis Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, New York;

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Alex Soroceanu Department of Orthopedic Surgery, University of Calgary, Alberta, Canada;

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D. Kojo Hamilton Department of Neurosurgery, University of Pittsburgh, Pennsylvania;

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Michael P. Kelly Department of Orthopedic Surgery, Rady Children’s Hospital, San Diego, California;

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Munish Gupta Department of Orthopedic Surgery, Washington University, St. Louis, Missouri;

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Robert Hart Department of Orthopaedic Surgery, Swedish Medical Center, Seattle, Washington;

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Frank J. Schwab Department of Orthopedic Surgery, Lennox Hill Hospital, New York, New York;

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Douglas Burton Department of Orthopaedic Surgery, University of Kansas Medical Center, Kansas City, Kansas;

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Christopher P. Ames Department of Neurological Surgery, University of California, San Francisco, California; and

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Christopher I. Shaffrey Departments of Neurosurgery and Orthopedic Surgery, Duke University, Durham, North Carolina

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Justin S. Smith Department of Neurosurgery, University of Virginia, Charlottesville, Virginia;

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OBJECTIVE

Adult cervical deformity (ACD) has high complication rates due to surgical complexity and patient frailty. Very few studies have focused on longer-term outcomes of operative ACD treatment. The objective of this study was to assess minimum 2-year outcomes and complications of ACD surgery.

METHODS

A multicenter, prospective observational study was performed at 13 centers across the United States to evaluate surgical outcomes for ACD. Demographics, complications, radiographic parameters, and patient-reported outcome measures (PROMs; Neck Disability Index, modified Japanese Orthopaedic Association, EuroQol-5D [EQ-5D], and numeric rating scale [NRS] for neck and back pain) were evaluated, and analyses focused on patients with ≥ 2-year follow-up.

RESULTS

Of 169 patients with ACD who were eligible for the study, 102 (60.4%) had a minimum 2-year follow-up (mean 3.4 years, range 2–8.1 years). The mean age at surgery was 62 years (SD 11 years). Surgical approaches included anterior-only (22.8%), posterior-only (39.6%), and combined (37.6%). PROMs significantly improved from baseline to last follow-up, including Neck Disability Index (from 47.3 to 33.0) and modified Japanese Orthopaedic Association score (from 12.0 to 12.8; for patients with baseline score ≤ 14), neck pain NRS (from 6.8 to 3.8), back pain NRS (from 5.5 to 4.8), EQ-5D score (from 0.74 to 0.78), and EQ-5D visual analog scale score (from 59.5 to 66.6) (all p ≤ 0.04). More than half of the patients (n = 58, 56.9%) had at least one complication, with the most common complications including dysphagia, distal junctional kyphosis, instrumentation failure, and cardiopulmonary events. The patients who did not achieve 2-year follow-up (n = 67) were similar to study patients based on baseline demographics, comorbidities, and PROMs. Over the course of follow-up, 23 of the total 169 enrolled patients were reported to have died. Notably, these represent all-cause mortalities during the course of follow-up.

CONCLUSIONS

This multicenter, prospective analysis demonstrates that operative treatment for ACD provides significant improvement of health-related quality of life at a mean 3.4-year follow-up, despite high complication rates and a high rate of all-cause mortality that is reflective of the overall frailty of this patient population. To the authors’ knowledge, this study represents the largest and most comprehensive prospective effort to date designed to assess the intermediate-term outcomes and complications of operative treatment for ACD.

ABBREVIATIONS

ACD = adult cervical deformity; CSM = cervical spondylotic myelopathy; DJK = distal junctional kyphosis; EQ-5D = EuroQol-5D; HRQL = health-related quality of life; mJOA = modified Japanese Orthopaedic Association; NDI = Neck Disability Index; NRS = numeric rating scale; PROMs = patient-reported outcome measures; VAS = visual analog scale; VCR = vertebral column resection; 3CO = 3-column osteotomy.

OBJECTIVE

Adult cervical deformity (ACD) has high complication rates due to surgical complexity and patient frailty. Very few studies have focused on longer-term outcomes of operative ACD treatment. The objective of this study was to assess minimum 2-year outcomes and complications of ACD surgery.

METHODS

A multicenter, prospective observational study was performed at 13 centers across the United States to evaluate surgical outcomes for ACD. Demographics, complications, radiographic parameters, and patient-reported outcome measures (PROMs; Neck Disability Index, modified Japanese Orthopaedic Association, EuroQol-5D [EQ-5D], and numeric rating scale [NRS] for neck and back pain) were evaluated, and analyses focused on patients with ≥ 2-year follow-up.

RESULTS

Of 169 patients with ACD who were eligible for the study, 102 (60.4%) had a minimum 2-year follow-up (mean 3.4 years, range 2–8.1 years). The mean age at surgery was 62 years (SD 11 years). Surgical approaches included anterior-only (22.8%), posterior-only (39.6%), and combined (37.6%). PROMs significantly improved from baseline to last follow-up, including Neck Disability Index (from 47.3 to 33.0) and modified Japanese Orthopaedic Association score (from 12.0 to 12.8; for patients with baseline score ≤ 14), neck pain NRS (from 6.8 to 3.8), back pain NRS (from 5.5 to 4.8), EQ-5D score (from 0.74 to 0.78), and EQ-5D visual analog scale score (from 59.5 to 66.6) (all p ≤ 0.04). More than half of the patients (n = 58, 56.9%) had at least one complication, with the most common complications including dysphagia, distal junctional kyphosis, instrumentation failure, and cardiopulmonary events. The patients who did not achieve 2-year follow-up (n = 67) were similar to study patients based on baseline demographics, comorbidities, and PROMs. Over the course of follow-up, 23 of the total 169 enrolled patients were reported to have died. Notably, these represent all-cause mortalities during the course of follow-up.

CONCLUSIONS

This multicenter, prospective analysis demonstrates that operative treatment for ACD provides significant improvement of health-related quality of life at a mean 3.4-year follow-up, despite high complication rates and a high rate of all-cause mortality that is reflective of the overall frailty of this patient population. To the authors’ knowledge, this study represents the largest and most comprehensive prospective effort to date designed to assess the intermediate-term outcomes and complications of operative treatment for ACD.

In Brief

Adult cervical deformity (ACD) can markedly impact health-related quality of life (HRQL). The authors' objective was to prospectively assess minimum 2-year outcomes and complications of ACD surgery based on patients enrolled at 13 centers. Overall, 57% of patients had at least one complication. Patient-reported outcome measures of pain, disability, and health significantly improved from baseline to last follow-up. Despite high complication rates, operative treatment for ACD can significantly improve HRQL at minimum 2-year (mean 3.4-year) follow-up.

Adult cervical deformity (ACD) is a potentially debilitating condition with a broad range of etiologies, including degenerative, neoplastic, traumatic, autoimmune, infectious, congenital, iatrogenic, and neuromuscular pathologies.1,2 ACD can result in marked impact on health-related quality of life (HRQL) by producing neck and arm pain, myelopathy, swallowing and breathing difficulties, and loss of horizontal gaze.36

Historic studies indicated surgical treatment of ACD was associated with high complication rates.79 More recently, however, there has been renewed interest in treating these often complex deformities.1013 Advances in surgical techniques and spinal instrumentation, as well as improvements in anesthesia, critical care, and perioperative management have provided an improved opportunity to safely treat ACD.1421 Few high-quality studies exist that describe longer-term outcomes and complications of surgically treated patients with ACD, because most are limited by retrospective design, small numbers of patients, short follow-up, and single-surgeon or single-center cohorts.16,22,23

A recent prospective, multicenter study from Ailon and colleagues demonstrated that surgical treatment of ACD provides improvement in pain and function at 1-year follow-up.24 Although these findings are encouraging, it is important to evaluate whether these treatment effects are durable with longer follow-up and to assess the incidence of delayed complications.16,22,2527 Thus, there remains a significant knowledge gap with regard to intermediate and longer-term clinical outcomes and associated complications of ACD surgery.

The objective of this study was to evaluate minimum 2-year patient-reported outcomes and associated complications of surgical management of ACD based on a prospective, multicenter study. A secondary objective was to assess the predictors of all-cause mortality within 2 years of surgery. We hypothesized that operative treatment for ACD significantly improves HRQL at minimum 2-year follow-up, despite high rates of complications.

Methods

Study Design and Population

This is a multicenter, prospective cohort study conducted to assess the outcome of ACD among those who underwent surgical treatment at 13 centers across the United States. This study was registered with the ClinicalTrials.gov database (http://clinicaltrials.gov), and its registration no. is NCT01588054. It was approved by the institutional review boards of the participating institutions, and all participants signed informed consent. Eligible ACD patients were > 18 years of age and met at least one of the following radiographic criteria: cervical kyphosis (C2–7 sagittal Cobb angle ≥ 10°), cervical scoliosis (C2–7 coronal Cobb angle ≥ 10°), C2–7 sagittal vertical axis ≥ 4 cm, or chin-brow vertical angle ≥ 25° based on full-length, freestanding posteroanterior and lateral spine radiographs. Exclusion criteria were active spinal infection or neoplasm, acute cervical spine trauma, or pregnancy. Although primary analyses focused on patients with minimum 2-year follow-up, a summary of demographics and available complications and outcomes for patients who did not achieve 2-year follow-up is provided as a means of assessing for potential confounding effects on outcomes that may be introduced by patients lost to follow-up.

Data Collection

Baseline and postoperative follow-up data were collected using standardized forms. Administered patient-reported outcome measures (PROMs) included the following: modified Japanese Orthopaedic Association (mJOA) questionnaire; Neck Disability Index (NDI); numeric rating scale (NRS) score for neck and back pain; and EuroQol-5D (EQ-5D). Complications were classified as perioperative (≤ 30 days after surgery) or delayed (> 30 days after surgery). Complications were categorized as minor or major, with complications that involved surgical treatment or entailed prolonged or permanent morbidity classified as major, as previously defined.28 To improve the data collection, research study coordinators from each site attempted to contact all patients lost to follow-up who were not known to be dead. These efforts included a combination of telephone calls and direct mailings to complete PROMs and complication/reoperation data. Multiple attempts were made to contact patients lost to follow-up if initial attempts were unsuccessful. In addition, all-cause mortality was collected based on available medical records and through attempts to reach patients who were lost to follow-up.

Statistical Analysis

Statistical analysis was performed using IBM SPSS (version 27.0). Descriptive statistics were reported using means and SDs for continuous variables and frequencies with percentages for categorical variables. Categorical variables were assessed using the chi-square test and Fisher’s exact test according to the sample size, and the Student t-test was used for continuous variables. Continuous data were assessed using the Kolmogorov-Smirnov test for normality. A paired t-test was used to compare means of PROMs at baseline versus follow-up. A subanalysis of myelopathy improvement was performed for the patients with at least moderate baseline myelopathy (mJOA ≤ 14) as defined by Fehlings and colleagues.29 Univariate analysis was performed to identify factors associated with all-cause mortality within 2 years of surgery. Factors that were significant on univariate analysis were then applied to a multivariate logistic regression analysis. Adjusted ORs and their 95% CIs were reported. The final logistic regression model was reached after ensuring the adequacy of our data by using the Hosmer-Lemeshow test. The statistical significance level was set at p < 0.05 (2-sided).

Results

Patient Population

Baseline demographic, clinical, and radiographic parameters are summarized in Table 1. Of 169 patients who met inclusion criteria, 102 (60.4%) achieved minimum 2-year follow-up (mean 3.4 years, range 2–8.1 years) (Fig. 1). These 102 patients had a mean age of 61.7 years, and 63.7% were women. The most common deformity subtypes were cervical kyphosis (87.3%) and cervical sagittal imbalance (50.0%). Preoperative measures of HRQL demonstrated significant pain and disability (Table 1). The most common surgical approach was posterior-only (39.6%) followed by combined approaches (37.6%). The mean number of vertebrae fused anteriorly and posteriorly were 4.3 (SD 1.1) and 9.4 (SD 3.4), respectively.

TABLE 1.

Baseline demographic, clinical, and patient-reported outcomes, and operative parameters for 169 patients with ACD

ParameterAchieved Min 2-Yr FUp Value
Yes, n = 102No, n = 67
Demographics
 Sex, % women63.758.20.52
 Mean age, yrs (SD, range)61.7 (10.5, 31–83)61.1 (10.6, 41–85)0.71
Clinical parameters
 Mean BMI (SD, range)29.2 (7.8, 17–59)29.6 (7.2, 17–47)0.66
 Mean CCI (SD, range)1.1 (1.5, 0–6)0.8 (1.0, 0–4)0.45
 Depression, no. (%)34 (33.3)19 (28.4)0.61
 Smoker, no. (%)5 (4.9)8 (11.9)0.14
 Osteoporosis, no. (%)17 (16.7)11 (16.4)>0.99
 Diabetes, no. (%)12 (11.8)6 (9.0)0.80
 Previous cervical spine surgery, no. (%)41 (40.2)34 (50.7)0.20
Diagnosis
 CK, no. (%)89 (87.3)59 (88.1)>0.99
 CSI, no. (%)51 (50.0)40 (59.7)0.27
 Coronal deformity, no. (%)11 (10.8)3 (4.5)0.17
 PJK, no. (%)4 (3.9)4 (6.0)0.71
PROMs
 NDI, mean (SD)47.3 (16.2)49.1 (20.8)0.53
 mJOA score, mean (SD)13.9 (2.7)13.0 (2.9)0.05
 NRS neck pain score, mean (SD)6.7 (2.4)6.8 (2.7)0.93
 NRS back pain ccore, mean (SD)5.4 (2.9)5.2 (3.2)0.62
 EQ-5D score, mean (SD)0.73 (0.07)0.73 (0.07)0.97
 EQ-5D VAS score, mean (SD)59.0 (22.9)58.5 (22.8)0.91
Surgical parameters
 Approach, no. (%)*0.002
  Anterior only23 (22.8)5 (7.6)
  Posterior only40 (39.6)45 (68.2)
  Combined approaches38 (37.6)16 (24.2)
 No. of instrumented levels, mean (SD)
  Anterior4.3 (1.1)4.6 (1.5)0.54
  Posterior9.4 (3.4)11.4 (5.4)0.045
 3CO, no. (%)
  PSO12 (11.8)10 (14.9)0.64
  VCR4 (3.9)9 (13.4)0.025
 Op time in hrs, mean (SD)6.7 (3.9)6.2 (3.0)0.73
 Estimated blood loss in L, mean (SD)0.8 (1.5)1.1 (1.2) 0.039

BMI = body mass index; CCI = Charlson Comorbidity Index; CK = cervical kyphosis; CSI = cervical sagittal imbalance; FU = follow-up; min = minimum; PJK = proximal junctional kyphosis; PSO = pedicle subtraction osteotomy. Boldface type indicates statistical significance.

Data on approach were available in a total of 101 patients with and in 66 patients without a minimum 2-year follow-up.

FIG. 1.
FIG. 1.

Flowchart of patients enrolled, lost to follow-up, dead, and included for study analysis. For the 2 patients who died more than 2 years after surgery but were lost to follow-up before the 2-year visit, the deaths occurred at approximately 24 months and 34.8 months, respectively (see Table 4, cases 17 and 18). Of the 102 patients with minimum 2-year follow-up, 5 died after 2 years (see Table 4, cases 19–23).

For the 67 patients who did not achieve 2-year follow-up, the mean follow-up was 0.7 years (SD 0.4 years; range 0–1.6 years). In terms of baseline demographics, clinical parameters, diagnosis, and PROMs, these patients were similar to those with 2-year follow-up (Table 1). Patients without 2-year follow-up were more likely to have undergone a posterior approach, had more posterior levels instrumented, had a greater proportion of vertebral column resections (VCRs), and had greater blood loss (Table 1).

Complications

Table 2 summarizes the complications for patients with minimum 2-year follow-up. Overall, 58 (56.9%) patients had at least one complication. The most common complications included dysphagia (18.6%), distal junctional kyphosis (DJK; 6.9%), instrumentation failure (6.9%), cardiac events without arrest (6.9%), dysphonia (4.9%), mental status change/delirium (4.9%), nerve sensory deficit (3.9%), and respiratory failure (3.9%). Twelve patients underwent a total of 15 reoperations.

TABLE 2.

Summary of complications by category for 102 patients with ACD treated surgically and with minimum 2-year follow-up

Complication CategoryPeriop Complications, ≤30 daysDelayed Complications, >30 daysTotal Minor (%)/Major (%) [reop]
Minor (%)Major (%) [reop]Minor (%)Major (%) [reop]
Dysphagia8 (7.8)2 (2.0)7 (6.9)2 (2.0)15 (14.7)/4 (3.9)
DJK01 (1.0) [1]2 (2.0)4 (3.9) [3]2 (2.0)/5 (4.9) [4]
Instr failure0007 (6.9) [2]0 (0)/7 (6.9) [2]
Cardiac event—not arrest4 (3.9)2 (2.0)01 (1.0)4 (3.9)/3 (2.9)
Dysphonia1 (1.0)1 (1.0) [1]2 (2.0)1 (1.0)3 (2.9)/2 (2.0) [1]
MS change/delirium4 (3.9)001 (1.0)4 (3.9)/1 (1.0)
Nerve sensory deficit1 (1.0)1 (1.0)02 (2.0) [1]1 (1.0)/3 (2.9) [1]
Respiratory failure1 (1.0)2 (2.0)01 (1.0)1 (1.0)/3 (2.9)
Radiculopathy1 (1.0)02 (2.0)1 (1.0)3 (2.9)/1 (1.0)
Deep wound infection01 (1.0)02 (2.0) [2]0 (0)/3 (2.9) [2]
Cardiac arrest02 (2.0)01 (1.0)0 (0)/3 (2.9)
Nerve root motor deficit—not C501 (1.0)02 (2.0)0 (0)/3 (2.9)
Deep venous thrombosis01 (1.0)02 (2.0)0 (0)/3 (2.9)
Excessive bleeding; >4 L03 (2.9)000 (0)/3 (2.9)
Dural tear3 (2.9)0003 (2.9)/0 (0)
Organ failure—liver/kidney0002 (2.0)0 (0)/2 (2.0)
Pneumonia01 (1.0) (1.0)01 (1.0)0 (0)/2 (2.0)
Superficial wound infection2 (2.0)0002 (2.0)/0 (0)
Ileus2 (2.0)0002 (2.0)/0 (0)
Spinal cord deficit0001 (1.0) [1]0 (0)/1 (1.0) [1]
C5 motor deficit01 (1.0) [1]000 (0)/1 (1.0) [1]
Pseudarthrosis0001 (1.0) [1]0 (0)/1 (1.0) [1]
Instr painful/prominent0001 (1.0) [1]0 (0)/1 (1.0) [1]
Perforated ulcer01 (1.0) [1]000 (0)/1 (1.0) [1]
Vascular injury01 (1.0)000 (0)/1 (1.0) [1]
Loss of deformity correction0001 (1.0)0 (0)/1 (1.0) [1]
Urinary tract infection1 (1.0)0000 (0)/1 (1.0)
Wound seroma1 (1.0)0000 (0)/1 (1.0)
Other3 (2.9)1 (1.0)1 (1.0)1 (1.0) [1]4 (3.9)/2 (2.0) [1]
Total (%)32 (31.4)22 (21.6)14 (13.7)35 (34.3)103 (101.0)
Mean complications/pt0.310.220.140.341.01
Pts affected, no. (%)27 (26.5)14 (13.7)10 (9.8)25 (24.5)58 (56.9)

Instr = instrumentation; MS = mental status; pt = patient.

Death not included in complications. The numbers of major complications for each category that were associated with a reoperation are shown in square brackets. Some reoperations were associated with more than one major complication. Twelve patients underwent a total of 15 reoperations.

Table 3 provides a summary of the complications for the 67 patients without 2-year follow-up. Overall, 36 (53.7%) had at least one complication as of last available follow-up. Seven patients each underwent one reoperation. The proportion of patients who underwent reoperation did not differ significantly between those with and without 2-year follow-up (13.3% versus 10.4%, respectively, p > 0.99).

TABLE 3.

Summary of complications by category for 67 patients with ACD treated surgically and without minimum 2-year follow-up

Complication CategoryPeriop Complications, ≤30 daysDelayed Complications, >30 daysTotal Minor (%)/Major (%) [reop]
Minor (%)Major (%) [reop]Minor (%)Major (%) [reop]
Deep wound infection04 (6.0) [2]02 (3.0) [2]0 (0)/6 (9.0) [4]
Dysphagia1 (1.5)2 (3.0)1 (1.5)1 (1.5)2 (3.0)/3 (4.5)
DJK002 (3.0)2 (3.0)2 (3.0)/2 (3.0)
MS change/delirium4 (6.0)0004 (6.0)/0 (0)
Radiculopathy1 (1.5)2 (3.0)1 (1.5)02 (3.0)/2 (3.0)
Spinal cord deficit01 (1.5)02 (3.0) [2]0 (0)/3 (4.5) [2]
Nerve sensory deficit1 (1.5)002 (3.0) [1]1 (1.5)/2 (3.0) [1]
C5 motor deficit03 (4.5)000 (0)/3 (4.5)
Respiratory failure1 (1.5)1 (1.5)01 (1.5)1 (1.5)/2 (3.0)
Superficial wound infection2 (3.0)01 (1.5)03 (4.5)/0 (0)
Nerve root motor deficit—not C502 (3.0) [1]000 (0)/2 (3.0) [1]
Pulmonary embolism02 (3.0)000 (0)/2 (3.0)
Dural tear2 (3.0)0002 (3.0)/0 (0)
Organ failure—liver/kidney01 (1.5)000 (0)/1 (1.5)
Pneumonia0001 (1.5)0 (0)/1 (1.5)
Cardiac event—not arrest01 (1.5)000 (0)/1 (1.5)
Instr malposition01 (1.5)000 (0)/1 (1.5)
Instr painful/prominent0001 (1.5)0 (0)/1 (1.5)
Wound seroma1 (1.5)0001 (1.5)/0 (0)
Urinary tract infection1 (1.5)0001 (1.5)/0 (0)
Neuromonitoring anomaly01 (1.5)000 (0)/1 (1.5)
Other3 (4.5)0003 (4.5)/0 (0)
Total (%)17 (25.4)21 (31.3)5 (7.5)12 (17.9)55 (82.1)
Mean complications/pt0.250.310.070.180.82
Pts affected, no. (%)14 (20.9)16 (23.9)6 (9.0)10 (14.9)36 (53.7)

Death not included in complications. The mean overall follow-up for the 67 patients was 0.7 years (range 0–1.6 years, SD 0.4 years); 61 patients had at least a 30-day follow-up. The numbers of major complications for each category that were associated with a reoperation are shown in square brackets. Some reoperations were associated with more than one major complication. Seven patients each underwent 1 reoperation.

All-Cause Mortality

Table 4 shows the demographics, comorbidities, and surgical parameters for the 23 patients in whom death was reported. These represent all-cause deaths during the course of follow-up and are not necessarily attributable to operative treatment. The time interval between surgery and death ranged from 0.2 months to 63.6 months. The most common causes of death included myocardial infarction/heart failure (n = 4), pneumonia/cardiopulmonary failure (n = 4), sepsis (n = 2), and accidental (n = 2). For 7 patients the cause of death was unknown (Table 4). Of the 67 patients who did not achieve 2-year follow-up, 16 were dead before reaching the 2-year time point and 2 were dead after reaching the 2-year time point but had been lost to follow-up before 2 years.

TABLE 4.

Demographic and surgical parameters for all-cause mortality after surgical treatment in 23 patients with ACD

Case No.Age (yrs)/SexDiagnosisComorbidities/Previous Cervical SurgerySurgical ProcedureCause of DeathDeath (mos)*Complications, Excluding Death
153/MCK, CSICervical surgery (×2)C7 PSO, C4–T3 PIFOSA/narcotics0.2Partial spinal cord motor deficit
252/MCK, CSICurrent smoker, depression, cervical surgeryC4 ACF, C2–3 & C7–T1 ACDF, C4–5 PCO, C2–T2 PIFUnknown2.9None
385/MCKMI, angina, osteoporosis, pacemaker, PA, cervical surgery (×2)C2–L4 PIF, T4 PSO, multilevel PCOsPneumonia3.2Pneumonia, renal failure
449/FCKFormer smoker, pulmonary disease, depression, severe myelopathyC5–7 ACDF w/ platingUnknown3.9None
565/FCKFormer smoker, depression, RA, lupusC2–6 PIF, multilevel PCOsUnknown8.4None
655/MCKFormer smoker, morbid obesity, myelopathyC3–7 ACDF, C3–7 PIF, multilevel partial facetectomiesLeukemia9.6None
766/FPJKPrior T2–S1 w/ wound infection & instr removal, myelopathyC2–S1 PIF, iliac screws, T2 VCRUnknown12.0None
869/FCKTumor, osteoporosisC2–T5 PIF, T2 PSO, multilevel PCOMI13.5C5 motor deficit, reop for DJK
954/MCK, CSIDepression, diabetes, cervical surgeryT2 VCR, C5–T9 PIFMI15.6Nerve root motor deficit (not C5)
1067/MCK, CSILymphoma, renal failure, angina, pulmonary hypertensionC2–T10 PIF, T2 VCR, multilevel PCOsMI15.6None
1169/MCK, CSIDepressionC4–7 ACDF, C2–T4 PIFCardiopulmonary failure17.9Reop for DJK
1260/FCK, CSIFormer smoker, severe myelopathyC2–T12 PIF, T3 VCRSepsis due to decubitus ulcer19.2New minor radiculopathy
1361/FCK, CSIAS, cervical surgery (×3)Ext of previous occiput–T2 PIF to ilium, lumbar PSOSepsis21.4Deep wound infection
1450/FCKFormer smoker, depression, cervical surgery (×2)Revision C4–5 ACDF, revision C4–6 PCO, & PIFAccidental burn injury22.5Reop for instr malposition
1555/MCKFormer smoker, MIC4 & C6 ACF w/ plating, C2–T2 PIFUnknown22.8Instr failure (T2 screw fracture)
1666/FCK, CSICurrent smoker, osteoporosis, severe myelopathyC4 corpectomy, C5–6 ACDF, C2–T4 PIF, multilevel partial facetectomiesPneumonia22.8None
1775/MCK, CSIPast smokerC4–7 ACDF, C2–T3 PIFALS24.0C5 motor deficit
1866/MCK, CSIParkinson disease, past smoker, diabetes, cervical surgery (×2)C5–ilium PIF, T8 VCRAspiration pneumonia34.8None
1973/MCKOsteoporosis, cervical surgeryC1–T11 PIF, multilevel PCOsUnknown>24.0None
2057/FCK, CSIMarfan syndrome, cerebrovascular disease, asthmaC2–T8 PIFStroke, intracranial bleed45.6None
2157/MCKMI, pulmonary disease, cervical surgery, long-term steroidsC4–7 ACDF, C2–T2 PIFMVA51.6Dysphagia, periop minor respiratory failure & MS change
2267/FCKDepression, RA, long-term steroids, osteoporosisC4 & C5 ACF, Oc–T3 PIFUnknown58.8Instr failure, dysphagia
2381/MCKFormer smoker, diabetes, morbid obesity, myelopathyC3–7 ACDFSystolic heart failure63.6Pneumonia, dysphagia, cardiac event, perforated ulcer, reop for dysphonia

ACDF = anterior cervical discectomy and fusion; ACF = anterior cervical corpectomy and fusion; ALS = amyotrophic lateral sclerosis; AS = ankylosing spondylitis; Ext = extension; MI = myocardial infarction; MVA = motor vehicle accident; OSA = obstructive sleep apnea; PA = pernicious anemia; PCO = posterior column osteotomy; PIF = posterior instrumented fusion; RA = rheumatoid arthritis.

Time between index surgery and death. For the patient in case 8, death occurred 7.0 months after revision surgery. For the patient in case 11, death occurred 3.9 months after revision surgery.

Specific date of death not available. Times between index surgery and death were estimated based on last clinical follow-up date.

Minimum 2-year clinical follow-up obtained.

On univariate analysis (data not shown), only performance of 3-column osteotomy (3CO) and baseline mJOA score were significantly associated with all-cause mortality within 2 years of index surgery (Table 4, cases 1–17). Table 5 summarizes the multivariate logistic regression using these two factors, with the final model adjusted for patient age. Our results show that the odds of all-cause mortality were significantly higher among patients who had a 3CO compared to those who did not (adjusted OR 3.930; 95% CI 1.262–12.237, p = 0.018). Patients with worse myelopathy (lower preoperative mJOA score) had greater odds of all-cause mortality within 2 years of surgery (adjusted OR 0.794; 95% CI 0.650–0.971; p = 0.025).

TABLE 5.

Multivariate analysis of factors associated with all-cause mortality within 2 years of surgery for ACD

ParameterAdjusted OR (95% CI)p Value
Performance of 3CO, yes vs no3.930 (1.262–12.237)0.018
Preop mJOA score0.794 (0.650–0.971)0.025
Pt age0.983 (0.931–1.039)0.551

Logistic regression analysis with adjustment for patient age. Boldface type indicates statistical significance.

Clinical Outcomes

Baseline and minimum 2-year (mean 3.4 years) follow-up PROM scores for patients with minimum 2-year follow-up are summarized in Table 6. All outcome measures assessed demonstrated significant improvement, including NDI (p < 0.001), mJOA (p = 0.026; for patients with baseline score ≤ 14), neck pain NRS (p < 0.001), back pain NRS (p = 0.043), EQ-5D score (p < 0.001), and EQ-5D visual analog scale (VAS) score (p = 0.004).

TABLE 6.

Comparison of baseline and minimum 2-year (mean 3.4-year) follow-up clinical outcome parameters for 102 patients with ACD treated surgically

Outcome ParameterBaseline, Mean (SD)Min 2-Year FU, Mean (SD)p Value
NDI47.3 (16.2)33.0 (20.3)<0.001
mJOA
 All pts13.9 (2.7)14.3 (2.9)0.18
 Only pts w/ baseline mJOA ≤14, n = 4712.0 (1.7)12.8 (2.3)0.026
NRS scores
 Neck pain6.8 (2.4)3.8 (3.0)<0.001
 Back pain5.5 (2.9)4.8 (3.1)0.043
EQ-5D
 Score0.74 (0.07)0.78 (0.09)<0.001
 VAS59.5 (21.7)66.6 (19.4)0.004

Boldface type indicates statistical significance.

Baseline and last follow-up outcome scores for the 67 patients who did not achieve 2-year follow-up are summarized in Table 7. Compared with baseline, at last follow-up these patients demonstrated significant improvement in NDI (p = 0.002), mJOA (p = 0.017; for patients with baseline score ≤ 14), neck pain NRS (p < 0.001), and EQ-5D score (p = 0.003). No significant differences were noted for back pain NRS (p = 0.69) or EQ-5D VAS score (p = 0.14).

TABLE 7.

Comparison of baseline and last follow-up clinical outcome parameters for 67 patients with ACD treated surgically without minimum 2-year follow-up

Outcome ParameterBaseline, Mean (SD)Last FU, Mean (SD)p Value
NDI49.1 (20.8)42.0 (23.5)0.002
mJOA
 All pts13.0 (2.9)13.7 (3.2)0.11
 Only pts w/ baseline mJOA ≤14, n = 3711.4 (2.1)12.7 (3.2)0.017
NRS scores
 Neck pain6.8 (2.7)5.0 (3.0)<0.001
 Back pain5.2 (3.2)5.1 (3.1)0.69
EQ-5D
 Score0.74 (0.07)0.77 (0.09)0.003
 VAS57.1 (23.3)62.3 (26.1)0.14

The mean overall follow-up for the 67 patients was 0.7 years (range 0–1.6 years; SD 0.4 years). Boldface type indicates statistical significance.

Discussion

This prospective multicenter study provides an assessment of the clinical outcomes and rates of complications associated with surgical treatment for ACD at a minimum 2-year follow-up. Overall, 58 (56.9%) patients had at least one complication, with the most common complications including dysphagia, DJK, instrumentation failure, and cardiopulmonary events. The overall all-cause mortality rate during follow-up was high, especially among patients with the most severe deformities that required high-grade osteotomies and those who had more severe myelopathy. At a mean 3.4-year follow-up, patients surgically treated for ACD demonstrated significant improvement in all outcome measures assessed. To our knowledge, this study represents the largest and most comprehensive prospective effort to date that was designed to assess the intermediate-term outcomes and complications of operative treatment for ACD.

Although several previous reports have suggested the benefits of operative treatment for ACD, these studies have been limited by retrospective design, small numbers of patients, single-surgeon or single-center cohorts, and relatively short follow-up.16,23 The present study complements these previous studies, including the work of Ailon and colleagues,24 who reported the 1-year outcomes of 55 patients with ACD treated with surgery. These authors noted significant improvements in NDI, neck pain NRS, and EQ-5D scores, but cautioned that further follow-up would be necessary to assess the longer-term durability of these procedures.

In the present study, 47 (46.1%) patients had at least moderate myelopathy (mJOA score ≤ 14)29 prior to surgery, and at the minimum 2-year follow-up these patients had significant improvement in mJOA scores (from 12.0 to 12.8, p = 0.026). In a large prospective study focused on cervical spondylotic myelopathy (CSM), Fehlings and colleagues29 reported an average improvement in mJOA score of 2.88 at 1 year after surgical decompression. The reason for the more modest myelopathy improvement in the present series of patients with ACD compared with that of patients with CSM is unclear. One explanation may relate to the chronicity of the spinal cord compromise, with longer duration potentially associated with less reversible injury. In the series of patients with CSM reported by Fehlings and colleagues, the mean duration of CSM symptoms prior to surgery was 25.8 months. Although the duration of myelopathy symptoms prior to ACD surgery in the present study was not specifically collected, it is possible that the duration was longer than that of the patients with CSM, given that many cervical deformities may remain untreated for longer periods of time due to the relative magnitude of the surgery and the common desire to exhaust nonoperative treatments. It is also possible that the type of spinal cord compromise may be different in patients with cervical deformities and may be less reversible. For example, previous studies have shown the potential for significant increase in intramedullary pressure with cervical kyphosis, with resulting demyelination and neuronal loss due to continuous mechanical compression and vascular changes.30,31

Although previous studies have documented high complication rates with ACD surgery,22,27,32 the rates in the present study are higher, likely to be reflective of the longer follow-up and prospective design, with focus on complication data collection. Assessment of these complications may serve as a basis to develop techniques and strategies to reduce the occurrence of complications. For example, the use of intrawound vancomycin powder may help to avert surgical site infection.33,34 Tranexamic acid use during ACD surgery may reduce the risk of bleeding and the need for transfusion, which could help to reduce cardiopulmonary complications.35 Regarding the high rates of neurological deficit, some authors have suggested shifting 3COs from C7 or T1 to T2 in order to lessen the risk to intrinsic hand muscle innervation and reduce the risk of vertebral artery injury.36,37 Instrumentation failure was the most common delayed complication. For thoracolumbar deformity surgeries, many surgeons have applied supplementary rod constructs to reduce the occurrence of rod fractures.3840 Some surgeons have extrapolated this technique to ACD surgeries.41,42 Dysphagia and DJK remain challenging complications in ACD surgery that are in need of novel approaches to reduce their occurrence.

A previous report documented the high all-cause mortality rate among patients treated for ACD.43 In order to provide a more complete accounting of outcomes in the present study, we also detailed all-cause mortality. A total of 23 patients were known to have died during follow-up, with death occurring as early as 0.2 months and as late as 63.6 months following index surgery. Importantly, the vast majority of these deaths are probably not related to ACD surgery, but instead are likely to be attributable to a combination of the elderly population studied, the marked comorbidities present in many of the patients, and the general frailty of the population.44 Although no deaths in this cohort occurred intraoperatively or prior to hospital discharge, there were 4 (Table 4, cases 1–4) that could arguably be associated with ACD surgery due to their chronological proximity to treatment. In addition, 1 patient (Table 4, case 11) died due to cardiopulmonary failure 3.9 months after reoperation for DJK. Other deaths could have had some indirect association with operative treatment, but this is less clear. It is notable that the only factors significantly associated with all-cause mortality within 2 years of index surgery were performance of a 3CO and worse baseline mJOA score. This suggests that the patients most vulnerable to all-cause mortality within 2 years of surgery were those who presented with the most severe deformities that required high-grade osteotomies and those who were the most neurologically impacted by their deformities.

In this prospective study, 60.4% achieved at least 2-year follow-up. Of the remaining 67 patients, 18 were either dead prior to reaching 2-year follow-up or died after 2 years but without follow-up obtained. The reasons that the remaining patients did not achieve 2-year follow-up are unknown. Among those lost to follow-up before 2 years, there did not appear to be an unusual number of complications or a disproportionate number of more impactful complications compared with those who achieved 2-year follow-up. In addition, the outcome scores as of last available follow-up demonstrated significant improvements across all measures. Thus, it does not appear that the primary reason that some patients were lost to follow-up before 2 years was due to complications or lack of clinical improvement. Patients lost to follow-up were more likely to have undergone more extensive posterior procedures, including more instrumented levels and VCRs, which could have negatively affected follow-up, especially since performance of a 3CO was an independent risk factor for all-cause mortality within 2 years of surgery.

Strengths of the present study include the prospective multicenter study design, the length of follow-up, the relatively large sample size, and the use of standardized questionnaires to collect patient information and outcomes to ensure consistent and complete data collection. Limitations to this study include the relatively high loss to follow-up (40%), which introduces a potential for selection bias due to the longitudinal nature of the study. We attempted to rectify this by evaluating the baseline data for the patients lost to follow-up and comparing this cohort to the patients with follow-up data, which demonstrated similarities in demographic, radiographic, and PROM data. However, we acknowledge that the baseline similarities between the cohorts with and without follow-up cannot guarantee similar treatment outcomes. Attempts are currently underway to improve long-term outcomes for our prospective studies, with hopes to further improve the informative capacity of our data. In addition, there are no widely accepted PROMs that are specific to patients with ACD, necessitating the use of more general outcome measures that are not disease specific. Thus, the outcome measures used may be limited in capturing the changes occurring in this patient population following surgery.

Conclusions

This multicenter, prospective analysis demonstrates that operative treatment for ACD can provide significant improvement of HRQL at a mean 3.4-year follow-up. This study offers useful insights into the potential benefits of ACD surgical treatment and better understanding of its functional impact and high rates of complications that necessitate a careful risk-benefit assessment when considering surgery. Further analyses are underway to assess the durability and cost-effectiveness of surgical treatment for ACD.

Acknowledgments

The ISSG is funded through research grants from DePuy Synthes.

Disclosures

Dr. Bess is a consultant for Alphatec and Mirus. He is a patent holder with K2M Stryker, and NuVasive. He has received clinical or research support for the study described (includes equipment or material) from DePuy Synthes. He receives support of a non–study-related clinical or research effort that he oversees from Medtronic, Globus, SeaSpine, K2M Stryker, Carlsmed, Orthofix, NuVasive, and the ISSGF. He is in the speakers bureau for Alphatec and Stryker, and he receives royalties from K2M Stryker and NuVasive. Mr. Line is a consultant for the ISSG. Dr. Lafage receives honoraria from Stryker, Implanet, and DePuy Synthes Spine. She is a consultant for Alphatec and Globus Medical, and receives royalties from NuVasive. She owns VFT Solutions LLC. Dr. Klineberg is a consultant for DePuy Synthes, Stryker, and Medicrea/Medtronic. He receives honoraria from AO Spine, and is also the fellowship director chair at AO Spine. Dr. Kim receives royalties from Zimmer Biomet, Surgical Acuity, and K2M-Stryker. He is a consultant for NuVasive. He receives support for a non–study-related clinical or research effort that he oversees from the ISSGF and SI-Bone. Dr. Passias is a consultant and is on the advisory board for Medtronic; is a consultant and is involved with product development for Globus; and consults/provides research support for Cerapedics. Dr. Gum is a consultant for Acuity, DePuy, Medtronic, NuVasive, and Stryker. He receives royalties from Acuity, Medtronic, and NuVasive. He is an employee of Norton Healthcare, Inc. He has a less than 1% ownership in Cingulate Therapeutics. He is a patent holder with Medtronic, and is in the speakers bureau for Medtronic and Stryker. He receives honoraria from Baxter, Broadwater, NASS, and Pacira Pharmaceuticals. He receives clinical or research support for the study described (includes equipment or material) from the following: Pfizer; Texas Scottish Rites Hospital; Alan L. & Jacqueline B. Stuart Spine Research Society; Cerapedics, Inc.; Scoliosis Research Society; Biom’Up; Empirical Spine, Inc.; National Spine Health Foundation; Stryker; and Medtronic. He is a reviewer for Global Spine Journal, Spine Deformity, and The Spine Journal. He is on the medical scientific board for the National Spine Health Foundation. Dr. Eastlack has direct stock ownership in SI Bone, SeaSpine, NuVasive, and Alphatec. He is a consultant for SI Bone, SeaSpine, NuVasive, Medtronic, J/J, Carevature, Spinal Elements, Biedermann Motech, and NEO Spine. He is a patent holder with SI Bone, Stryker, Globus, and SeaSpine. He receives support of a non–study-related clinical or research effort that he oversees from NuVasive, Medtronic, SeaSpine, and Spinal Elements. He is in the speakers bureau for Radius. He receives royalties from Globus, SI Bone, SeaSpine, and NuVasive. Dr. Mundis is a consultant for NuVasive, SeaSpine, SI Bone, Carlsmed, and Viseon. He has direct stock ownership in SeaSpine and Alphatec. He receives royalties from NuVasive and Stryker, and he is a patent holder with Stryker. Dr. Protopsaltis is a consultant for Globus, NuVasive, Medtronic, and K2M Stryker. He receives royalties from Altus, and has stock options from Spine Align and Torus Medical. Dr. Kelly has received honoraria from Spine. He is on the board of directors for the Setting Scoliosis Straight Foundation, and also receives research support unrelated to this study from them. Dr. Gupta receives royalties from DePuy, Innomed, and Globus. He is a consultant for DePuy, Medtronic, and Globus, Alphatec—began and ended in 2019. He has direct stock ownership in J&J. He has received honoraria from AO Spine, Wright State, LSU, and the Malaysian Spine Society. He is also on the Scoliosis Research Society’s board of directors (nonfinancial—his travel is paid for being course chair), and he is on the National Spine Health Foundation’s scientific advisory board (nonfinancial—voluntary) Dr. Hart is a consultant for DePuy, Globus, Medtronic, Allosource, SeaSpine, ProprioVision, and Orthofix. He receives clinical or research support for the study described (includes equipment or material) from Misonix and DePuy. He is a member of the ISSG board. He receives royalties from DePuy, Globus, and SeaSpine. Dr. Schwab has direct stock ownership in VFT Solutions and SeaSpine. He is a consultant for Zimmer Biomet, Medtronic, and Mainstay Medical. He receives royalties from Zimmer Biomet, Medtronic, and Medicrea. He receives support of a non–study-related clinical or research effort that he oversees from DePuy, K2M, NuVasive, Medtronic, Globus, Allosource, Orthofix, and SI Bone (paid through the ISSG Foundation). He is on the executive committee for the ISSG. Dr. Burton has direct stock ownership in Progenerative Medical. He is a consultant for Globus, and receives royalties from Globus and Blue Ocean Spine. He receives support of a non–study-related clinical or research effort that he oversees from DePuy. Dr. Ames receives royalties from Stryker, Biomet Zimmer Spine, DePuy Synthes, NuVasive, Next Orthosurgical, K2M, and Medicrea. He is a consultant for DePuy Synthes, Medtronic, Medicrea, K2M, Agada Medical, and Carlsmed. He performs research for Titan Spine, DePuy Synthes, and the ISSG. He is on the editorial board for Operative Neurosurgery. He receives grant funding from SRS. He is on the executive committee of the ISSG. He is the director of Global Spine Analytics. He is the committee chair for SRS Safety and Value Committee. Dr. Shaffrey is a consultant for Medtronic, NuVasive, SI Bone, and Proprio. He receives royalties from and is a patent holder with Medtronic, NuVasive, and SI Bone. The has direct stock ownership in NuVasive. Dr. Smith is a consultant for Zimmer Biomet, Carlsmed, DePuy Synthes, NuVasive, Stryker, SeaSpine, and Cerapedics. He receives royalties from Zimmer Biomet, NuVasive, and Thieme. He receives clinical or research support for the study described (includes equipment or material) from DePuy Synthes/ISSGF, and he also receives support of a non–study-related clinical or research effort that he oversees from DePuy Synthes/ISSGF, NuVasive, and AO Spine. He owns stock in Alphatec and NuVasive.

Author Contributions

Conception and design: Smith, Bess, Line, V Lafage, Klineberg, Kim, Passias, Kebaish, Eastlack, Daniels, Mundis, Hostin, Protopsaltis, Kelly, Gupta, Hart, Schwab, Burton, Ames, Shaffrey. Acquisition of data: Smith, Bess, Line, V Lafage, R Lafage, Klineberg, Kim, Passias, Gum, Kebaish, Eastlack, Daniels, Mundis, Hostin, Protopsaltis, Soroceanu, Hamilton, Kelly, Gupta, Hart, Schwab, Burton, Ames, Shaffrey. Analysis and interpretation of data: Smith, Elias, Nasser. Drafting the article: Smith, Elias, Nasser. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Smith. Statistical analysis: Smith, Elias. Administrative/technical/material support: Bess, V Lafage, R Lafage. Study supervision: Smith, Bess, Ames, Shaffrey.

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    • Export Citation
  • 29

    Fehlings MG, Wilson JR, Kopjar B, et al. Efficacy and safety of surgical decompression in patients with cervical spondylotic myelopathy: results of the AOSpine North America prospective multi-center study. J Bone Joint Surg Am. 2013;95(18):16511658.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30

    Chavanne A, Pettigrew DB, Holtz JR, Dollin N, Kuntz C IV. Spinal cord intramedullary pressure in cervical kyphotic deformity: a cadaveric study. Spine (Phila Pa 1976). 2011;36(20):16191626.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 31

    Shimizu K, Nakamura M, Nishikawa Y, Hijikata S, Chiba K, Toyama Y. Spinal kyphosis causes demyelination and neuronal loss in the spinal cord: a new model of kyphotic deformity using juvenile Japanese small game fowls. Spine (Phila Pa 1976). 2005;30(21):23882392.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32

    Koller H, Ames C, Mehdian H, et al. Characteristics of deformity surgery in patients with severe and rigid cervical kyphosis (CK): results of the CSRS-Europe multi-centre study project. Eur Spine J. 2019;28(2):324344.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 33

    Kang DG, Holekamp TF, Wagner SC, Lehman RA Jr. Intrasite vancomycin powder for the prevention of surgical site infection in spine surgery: a systematic literature review. Spine J. 2015;15(4):762770.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34

    Theologis AA, Demirkiran G, Callahan M, Pekmezci M, Ames C, Deviren V. Local intrawound vancomycin powder decreases the risk of surgical site infections in complex adult deformity reconstruction: a cost analysis. Spine (Phila Pa 1976). 2014;39(22):18751880.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 35

    Peters A, Verma K, Slobodyanyuk K, et al. Antifibrinolytics reduce blood loss in adult spinal deformity surgery: a prospective, randomized controlled trial. Spine (Phila Pa 1976). 2015;40(8):E443E449.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 36

    Yuk FJ, Rasouli JJ, Arginteanu MS, et al. The case for T2 pedicle subtraction osteotomy in the surgical treatment of rigid cervicothoracic deformity. J Neurosurg Spine. 2019;32(2):248257.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 37

    Theologis AA, Tabaraee E, Funao H, et al. Three-column osteotomies of the lower cervical and upper thoracic spine: comparison of early outcomes, radiographic parameters, and peri-operative complications in 48 patients. Eur Spine J. 2015;24(suppl 1):S23S30.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 38

    Gupta S, Eksi MS, Ames CP, et al. A novel 4-rod technique offers potential to reduce rod breakage and pseudarthrosis in pedicle subtraction osteotomies for adult spinal deformity correction. Oper Neurosurg (Hagerstown). 2018;14(4):449456.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 39

    Smith JS, Shaffrey E, Klineberg E, et al. Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity. J Neurosurg Spine. 2014;21(6):9941003.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 40

    Tang JA, Leasure JM, Smith JS, Buckley JM, Kondrashov D, Ames CP. Effect of severity of rod contour on posterior rod failure in the setting of lumbar pedicle subtraction osteotomy (PSO): a biomechanical study. Neurosurgery. 2013;72(2):276283.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 41

    Cady-McCrea CI, Galgano MA. C2 quad-screws facilitate 4-rod fixation across the cervico-thoracic junction. Surg Neurol Int. 2021;12:40.

  • 42

    Godzik J, Lehrman JN, Farber SH, et al. Optimizing cervicothoracic junction biomechanics after C7 pedicle subtraction osteotomy: a cadaveric study of stability and rod strain. World Neurosurg. 2022;160:e278e287.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 43

    Smith JS, Shaffrey CI, Kim HJ, et al. Prospective multicenter assessment of all-cause mortality following surgery for adult cervical deformity. Neurosurgery. 2018;83(6):12771285.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 44

    Miller EK, Ailon T, Neuman BJ, et al. Assessment of a novel adult cervical deformity frailty index as a component of preoperative risk stratification. World Neurosurg. 2018;109:e800e806.

    • PubMed
    • Search Google Scholar
    • Export Citation
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Illustrations from Hagan et al. (pp 843–850). © Albert Telfeian, published with permission.

  • FIG. 1.

    Flowchart of patients enrolled, lost to follow-up, dead, and included for study analysis. For the 2 patients who died more than 2 years after surgery but were lost to follow-up before the 2-year visit, the deaths occurred at approximately 24 months and 34.8 months, respectively (see Table 4, cases 17 and 18). Of the 102 patients with minimum 2-year follow-up, 5 died after 2 years (see Table 4, cases 19–23).

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    Grosso MJ, Hwang R, Mroz T, Benzel E, Steinmetz MP. Relationship between degree of focal kyphosis correction and neurological outcomes for patients undergoing cervical deformity correction surgery. J Neurosurg Spine. 2013;18(6):537544.

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    Uchida K, Nakajima H, Sato R, et al. Cervical spondylotic myelopathy associated with kyphosis or sagittal sigmoid alignment: outcome after anterior or posterior decompression. J Neurosurg Spine. 2009;11(5):521528.

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    Shamji MF, Ames CP, Smith JS, Rhee JM, Chapman JR, Fehlings MG. Myelopathy and spinal deformity: relevance of spinal alignment in planning surgical intervention for degenerative cervical myelopathy. Spine (Phila Pa 1976). 2013;38(22 Suppl 1):S147S148.

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    Grosso MJ, Hwang R, Krishnaney AA, Mroz TE, Benzel EC, Steinmetz MP. Complications and outcomes for surgical approaches to cervical kyphosis. J Spinal Disord Tech. 2015;28(7):E385E393.

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    Hann S, Chalouhi N, Madineni R, et al. An algorithmic strategy for selecting a surgical approach in cervical deformity correction. Neurosurg Focus. 2014;36(5):E5.

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    Kim HJ, Piyaskulkaew C, Riew KD. Comparison of Smith-Petersen osteotomy versus pedicle subtraction osteotomy versus anterior-posterior osteotomy types for the correction of cervical spine deformities. Spine (Phila Pa 1976). 2015;40(3):143146.

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    Scheer JK, Ames CP, Deviren V. Assessment and treatment of cervical deformity. Neurosurg Clin N Am. 2013;24(2):249274.

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    Smith JS, Lafage V, Schwab FJ, et al. Prevalence and type of cervical deformity among 470 adults with thoracolumbar deformity. Spine (Phila Pa 1976). 2014;39(17):E1001E1009.

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  • 22

    Etame AB, Than KD, Wang AC, La Marca F, Park P. Surgical management of symptomatic cervical or cervicothoracic kyphosis due to ankylosing spondylitis. Spine (Phila Pa 1976). 2008;33(16):E559E564.

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    Cho SK, Safir S, Lombardi JM, Kim JS. Cervical spine deformity: indications, considerations, and surgical outcomes. J Am Acad Orthop Surg. 2019;27(12):e555e567.

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    Ailon T, Smith JS, Shaffrey CI, et al. Outcomes of operative treatment for adult cervical deformity: a prospective multicenter assessment with 1-year follow-up. Neurosurgery. 2018;83(5):10311039.

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  • 25

    Smith JS, Ramchandran S, Lafage V, et al. Prospective multicenter assessment of early complication rates associated with adult cervical deformity surgery in 78 patients. Neurosurgery. 2016;79(3):378388.

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  • 26

    Smith JS, Shaffrey CI, Lafage R, et al. Three-column osteotomy for correction of cervical and cervicothoracic deformities: alignment changes and early complications in a multicenter prospective series of 23 patients. Eur Spine J. 2017;26(8):21282137.

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  • 27

    Smith JS, Buell TJ, Shaffrey CI, et al. Prospective multicenter assessment of complication rates associated with adult cervical deformity surgery in 133 patients with minimum 1-year follow-up. J Neurosurg Spine. 2020;33(5):588600.

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  • 28

    Klineberg EO, Wick JB, Lafage R, et al. Development and validation of a multidomain surgical complication classification system for adult spinal deformity. Spine (Phila Pa 1976). 2021;46(4):E267E273.

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  • 29

    Fehlings MG, Wilson JR, Kopjar B, et al. Efficacy and safety of surgical decompression in patients with cervical spondylotic myelopathy: results of the AOSpine North America prospective multi-center study. J Bone Joint Surg Am. 2013;95(18):16511658.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30

    Chavanne A, Pettigrew DB, Holtz JR, Dollin N, Kuntz C IV. Spinal cord intramedullary pressure in cervical kyphotic deformity: a cadaveric study. Spine (Phila Pa 1976). 2011;36(20):16191626.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 31

    Shimizu K, Nakamura M, Nishikawa Y, Hijikata S, Chiba K, Toyama Y. Spinal kyphosis causes demyelination and neuronal loss in the spinal cord: a new model of kyphotic deformity using juvenile Japanese small game fowls. Spine (Phila Pa 1976). 2005;30(21):23882392.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32

    Koller H, Ames C, Mehdian H, et al. Characteristics of deformity surgery in patients with severe and rigid cervical kyphosis (CK): results of the CSRS-Europe multi-centre study project. Eur Spine J. 2019;28(2):324344.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 33

    Kang DG, Holekamp TF, Wagner SC, Lehman RA Jr. Intrasite vancomycin powder for the prevention of surgical site infection in spine surgery: a systematic literature review. Spine J. 2015;15(4):762770.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34

    Theologis AA, Demirkiran G, Callahan M, Pekmezci M, Ames C, Deviren V. Local intrawound vancomycin powder decreases the risk of surgical site infections in complex adult deformity reconstruction: a cost analysis. Spine (Phila Pa 1976). 2014;39(22):18751880.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 35

    Peters A, Verma K, Slobodyanyuk K, et al. Antifibrinolytics reduce blood loss in adult spinal deformity surgery: a prospective, randomized controlled trial. Spine (Phila Pa 1976). 2015;40(8):E443E449.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 36

    Yuk FJ, Rasouli JJ, Arginteanu MS, et al. The case for T2 pedicle subtraction osteotomy in the surgical treatment of rigid cervicothoracic deformity. J Neurosurg Spine. 2019;32(2):248257.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 37

    Theologis AA, Tabaraee E, Funao H, et al. Three-column osteotomies of the lower cervical and upper thoracic spine: comparison of early outcomes, radiographic parameters, and peri-operative complications in 48 patients. Eur Spine J. 2015;24(suppl 1):S23S30.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 38

    Gupta S, Eksi MS, Ames CP, et al. A novel 4-rod technique offers potential to reduce rod breakage and pseudarthrosis in pedicle subtraction osteotomies for adult spinal deformity correction. Oper Neurosurg (Hagerstown). 2018;14(4):449456.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 39

    Smith JS, Shaffrey E, Klineberg E, et al. Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity. J Neurosurg Spine. 2014;21(6):9941003.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 40

    Tang JA, Leasure JM, Smith JS, Buckley JM, Kondrashov D, Ames CP. Effect of severity of rod contour on posterior rod failure in the setting of lumbar pedicle subtraction osteotomy (PSO): a biomechanical study. Neurosurgery. 2013;72(2):276283.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 41

    Cady-McCrea CI, Galgano MA. C2 quad-screws facilitate 4-rod fixation across the cervico-thoracic junction. Surg Neurol Int. 2021;12:40.

  • 42

    Godzik J, Lehrman JN, Farber SH, et al. Optimizing cervicothoracic junction biomechanics after C7 pedicle subtraction osteotomy: a cadaveric study of stability and rod strain. World Neurosurg. 2022;160:e278e287.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 43

    Smith JS, Shaffrey CI, Kim HJ, et al. Prospective multicenter assessment of all-cause mortality following surgery for adult cervical deformity. Neurosurgery. 2018;83(6):12771285.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 44

    Miller EK, Ailon T, Neuman BJ, et al. Assessment of a novel adult cervical deformity frailty index as a component of preoperative risk stratification. World Neurosurg. 2018;109:e800e806.

    • PubMed
    • Search Google Scholar
    • Export Citation

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