Anterior cervical discectomy and fusion: Surgical indications and outcomes

Clinicosocial determinants of hospital stay following cervical decompression: A public healthcare perspective and machine learning model

OBJECTIVE

Post-operative length of hospital stay (LOS) is a valuable measure for monitoring quality of care provision, patient recovery, and guiding hospital resource management. But the impact of patient ethnicity, socio-economic deprivation as measured by the indices of multiple deprivation (IMD), and pre-existing health conditions on LOS post-anterior cervical decompression and fusion (ACDF) is under-researched in public healthcare settings.

METHODS

From 2013 to 2023, a retrospective study at a single center reviewed all ACDF procedures. We analyzed 14 non-clinical predictors-including demographics, comorbidities, and socio-economic status-to forecast a categorized LOS: short (≤2 days), medium (2-3 days), or long (>3 days). Three machine learning (ML) models were developed and assessed for their prediction reliability.

RESULTS

2033 ACDF patients were analyzed; 79.44 % had a LOS ≤ 2 days. Significant predictors of LOS included patient sex (HR:0.81[0.74-0.88], p < 0.005), IMD decile (HR:1.38[1.24-1.53], p < 0.005), smoking (HR:1.24[1.12-1.38], p < 0.005), DM (HR:0.70[0.59-0.84], p < 0.005), and COPD (HR:0.66, p = 0.01). Asian patients had the highest mean LOS (p = 0.003). Testing on 407 patients, the XGBoost model achieved 80.95 % accuracy, 71.52 % sensitivity, 85.76 % specificity, 71.52 % positive predictive value, and a micro F1 score of 0.715. This model is available at: https://acdflos.streamlit.app.

CONCLUSIONS

Utilizing non-clinical pre-operative parameters such as patient ethnicity, socio-economic deprivation index, and baseline comorbidities, our ML model effectively predicts postoperative LOS for patient undergoing ACDF surgeries. Yet, as the healthcare landscape evolves, such tools will require further refinement to integrate peri and post-operative variables, ensuring a holistic decision support tool.

Iatrogenic pharyngo-esophageal diverticulum post-anterior cervical discectomy and fusion: A case report and review of literature

Objectives

The purpose of this study is to report a case of iatrogenic pharyngoesophageal diverticulum post-anterior cervical discectomy and fusion (ACDF) surgery, its management and management of postoperative complications. We also did a thorough review of literature about iatrogenic pharyngoesophageal diverticulum which is a rarely encountered complication occurring after a commonly performed surgery; ACDF.

Methods

Here we describe a case of iatrogenic pharyngoesophageal diverticulum post-ACDF surgery. In this paper we also make comparisons to the 23 cases reported in the literature in terms of: presentations, clinical findings, management courses, and complications. This study was approved by the Institution Review Board of Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia. (Ref. no.: IRB-2023-01-473). The reported subject provided written informed consent before initiation of this study.

Results

Our case is a 45-year-old male with a history of ACDF surgery 8 years ago. He presented with dysphagia and regurgitations which started 1 year after ACDF. He was labeled as a case of Zenker's diverticulum and underwent multiple failed open and endoscopic surgeries prior to presenting to us. Upon presenting to our center, barium swallow showed the pharyngoesophageal diverticulum. Patient definitive diagnosis of iatrogenic rather than Zenker's diverticulum was established intra-operatively with esophagoscopy which revealed exposed hardware inside the diverticulum. He underwent open diverticulectomy and diverticulopexy. Postoperatively he developed pharyngocutanous fistula and right vocal fold palsy, both successfully managed conservatively.

Conclusion

Iatrogenic Pharyngoesophageal diverticulum is a rare complication following ACDF, however prolonged dysphagia shall warrant further investigation by contrast studies. Open diverticulectomy with muscle reinforcement is a good management modality. Due to the complicated anatomy secondary to previous operations, we recommend conservative management for patients with postoperative pharyngocutaneous fistula.

The prognostic utility of neutrophil-lymphocyte ratio in spinal surgery: A systematic review and meta-analysis

PURPOSE

Neutrophil-lymphocyte ratio (NLR) is reportedly an effective prognostic tool across various medical and surgical fields, but its value in spinal surgery is unestablished. We aim to investigate the relationship between elevated baseline/postoperative NLR and patient outcomes in spinal surgery.

MATERIALS AND METHODS

We performed a systematic search in PubMed, EMBASE, and SCOPUS databases for studies investigating the prognostic value of NLR in spine patients.Odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were analysed on the RevMan 5.4 software. Where meta-analysis was not possible, we vote-counted the direction of the effect of elevated NLR. The GRADE framework for prognostic factor research was utilised to assess the certainty of the evidence for each outcome measure.

RESULTS

Five outcome measures (overall survival, mortality, disease-free survival, functional recovery and complications) were assessed across 16 studies involving 5471 patients. Elevated baseline NLR was associated with reduced overall survival (HR: 1.63, 95 % CI: 1.05 - 2.54) (GRADE: low) and worsened functional recovery (OR: 0.93, 95 % CI: 0.87 - 0.98) (GRADE: low). There was no association between baseline NLR and disease-free survival (HR: 2.42, 95 % CI: 0.49 - 11.83) (GRADE: very low) or mortality (OR: 1.39, 95 % CI: 0.41 - 4.75) (GRADE: very low). Elevated NLR levels measured on days 3-4 and days 6-7 postoperatively, but not NLR measured at baseline or on days 1-2 postoperatively, were associated with greater risks of complications (GRADE: low).

CONCLUSIONS

NLR is an objective tool with the potential to identify the patients that would benefit from surgery and facilitate shared decision-making.

A Novel Method for Tracking Neck Motions Using a Skin-Conformable Wireless Accelerometer: A Pilot Study

Introduction

Cervical spine disease is a leading cause of pain and disability. Degenerative conditions of the spine can result in neurologic compression of the cervical spinal cord or nerve roots and may be surgically treated with an anterior cervical discectomy and fusion (ACDF) in up to 137,000 people per year in the United States. A common sequelae of ACDF is reduced cervical range of motion (CROM) with patient-based complaints of stiffness and neck pain. Currently, tools for assessment of CROM are manual, subjective, and only intermittently utilized during doctor or physical therapy visits. We propose a skin-mountable acousto-mechanic sensor (ADvanced Acousto-Mechanic sensor; ADAM) as a tool for continuous neck motion monitoring in postoperative ACDF patients. We have developed and validated a machine learning neck motion classification algorithm to differentiate between eight neck motions (right/left rotation, right/left lateral bending, flexion, extension, retraction, protraction) in healthy normal subjects and patients.

Methods

Sensor data from 12 healthy normal subjects and 5 patients were used to develop and validate a Convolutional Neural Network (CNN).

Results

An average algorithm accuracy of 80.0 ± 3.8% was obtained for healthy normal subjects (94% for right rotation, 98% for left rotation, 65% for right lateral bending, 87% for left lateral bending, 89% for flexion, 77% for extension, 50% for retraction, 84% for protraction). An average accuracy of 67.5 ± 5.8% was obtained for patients.

Discussion

ADAM, with our algorithm, may serve as a rehabilitation tool for neck motion monitoring in postoperative ACDF patients. Sensor-captured vital signs and other events (extubation, vocalization, physical therapy, walking) are potential metrics to be incorporated into our algorithm to offer more holistic monitoring of patients after cervical spine surgery.

Cervical Radiculopathy: Focus on Factors for Better Surgical Outcomes and Operative Techniques

For patients with cervical radiculopathy, most studies have recommended conservative treatment as the first-line treatment; however, when conventional treatment fails, surgery is considered. A better understanding of the prognosis of cervical radiculopathy is essential to provide accurate information to the patients. If the patients complain of persistent and recurrent arm pain/numbness not respond to conservative treatment, or exhibit neurologic deficits, surgery is performed using anterior or posterior approaches. Anterior cervical discectomy and fusion (ACDF) has historically been widely used and has proven to be safe and effective. To improve surgical outcomes of ACDF surgery, many studies have been conducted on types of spacers, size/height/position of cages, anterior plating, patients' factors, surgical techniques, and so forth. Cervical disc replacement (CDR) is designed to reduce the incidence of adjacent segment disease during long-term follow-up by maintaining cervical spine motion postoperatively. Many studies on excellent indications for the CDR, proper type/size/shape/height of the implants, and surgical techniques were performed. Posterior cervical foraminotomy is a safe and effective surgical option to avoid complications associated with anterior approach and fusion surgery. Most recent literature demonstrated that all three surgical techniques for patients with cervical radiculopathy have clear advantages and disadvantages and reveal satisfactory surgical outcomes under a proper selection of patients and application of appropriate surgical methods. For this, it is important to fully understand the factors for better surgical outcomes and to adequately practice the operative techniques for patients with cervical radiculopathy.

The Effect of the Preoperative Severity of Neck Pain on Patient-Reported Outcome Measures and Minimum Clinically Important Difference Achievement After Anterior Cervical Discectomy and Fusion

OBJECTIVE

To compare patient-reported outcome measure (PROM) scores and minimum clinically important difference (MCID) achievement rates among patients undergoing single-level anterior cervical discectomy and fusion (ACDF) in patients with varying severity of preoperative visual analog scale (VAS) neck score.

METHODS

Patients with ACDF were grouped: severity of preoperative VAS neck score ≤8 or >8. Demographic/perioperative variables and PROMs (Patient-Reported Outcomes Measurement Information System Physical Function [PROMIS PF] score, 12-Item Short Form [SF-12] Mental Component Score [MCS], VAS neck/arm score, and Neck Disability Index [NDI]) were collected preoperatively/postoperatively. MCID attainment comparison by grouping was evaluated using χ² analysis.

RESULTS

A total of 137 patients were included (103 VAS neck preoperative score ≤8; 34 VAS neck preoperative score >8). The VAS neck preoperative score ≤8 cohort did not improve: 6 weeks PROMIS-PF score, 6 weeks SF-12 Physical Component Score [PCS], 12 weeks/1 year/2 years SF-12 MCS, 2 years VAS neck score, and 1 years/2 years VAS arm score (P ≤ 0.015, all). VAS neck preoperative score >8 did not improve: 6 weeks/12 weeks/2 years PROMIS-PF score, all time points SF-12 PCS, 6 weeks/12 weeks/1 year/2 years SF-12 MCS, and 2 years VAS arm score (P ≤ 0.013, all). VAS neck preoperative score >8 had inferior PROMIS-PF scores all time points except 1 year (P ≤ 0.036, all), lower SF-12 PCS 6 weeks/6 months (P ≤ 0.043, both), inferior SF-12 MCS at preoperative to 6 months (P ≤ 006, all), higher VAS neck score from preoperative to 6 months (P ≤ 0.018), higher VAS arm score preoperative/12 weeks/6 months (P ≤ 0.020, all), and higher NDI at preoperative/12 weeks/6 months (P ≤ 0.030, all). MCID attainment rates for VAS neck preoperative score >8 were greater for NDI 2 years (P = 0.040), lower for PROMIS-PF score 2 years, and overall (P = 0.018), lower for SF-12 MCS 12 weeks (P = 0.046), lower for VAS neck score 12 weeks to 1 year and overall (P ≤ 0.032, all), and lower for VAS arm score 6 weeks/1 year (P ≤ 0.030, both).

CONCLUSIONS

Patients with single-level ACDF presenting with greater baseline neck pain showed poorer physical function/pain/disability/mental health at preoperative/intermediate postoperative time points, but had comparable long-term PROMs by 2 years. MCID attainment was lower among patients with greater preoperative neck pain; MCID among the VAS neck score >8 cohort were only significantly inferior for neck pain.

Workers' Compensation Association With Clinical Outcomes After Anterior Cervical Diskectomy and Fusion

BACKGROUND

Research has suggested that workers' compensation (WC) status can result in poor outcomes after anterior cervical diskectomy and fusion (ACDF).

OBJECTIVE

To determine the influence WC status has on postoperative clinical outcomes after ACDF.

METHODS

A surgical database was reviewed for patients undergoing primary or revision single-level ACDF. Patients were grouped into WC vs Non-WC, and differences in baseline characteristics were assessed. Postoperative improvement was assessed for differences in mean scores between WC subgroups for visual analog scale (VAS) arm, VAS neck, 12-item Short Form Physical Composite Score, Patient-Reported Outcomes Measurement Information System physical function (PF), and Neck Disability Index (NDI) at preoperative and postoperative time points. Minimum clinically important difference (MCID) achievement was compared between groups.

RESULTS

The patient cohort included 44 with WC and 95 without. The cohort was 40% female with an average age of 48 years and mean body mass index of 30. Mean VAS arm, VAS neck, NDI, 12-item Short-Form Physical Composite Score, and Patient-Reported Outcomes Measurement Information System PF scores differed between groups; however, the difference was not sustained at the 1-yr time point. MCID achievement among WC subgroups was different for VAS arm (6 wk through 6 mo, P = .005), VAS neck (3 and 6 mo, P < .01), and NDI (3 and 6 mo, P < .05). No statistically significant difference was noted between cohorts for overall rates of MCID achievement for all patient-reported outcome measures collected.

CONCLUSION

WC patients reported similar preoperative and 1-yr postoperative neck and arm pain compared with non-WC patients after ACDF. One-yr MCID achievement rates were similar between cohorts for disability and PF scores.

Personalised gravitational loading of the cervical spine from biplanar X-rays for asymptomatic and clinical subjects in neutral standing position

BACKGROUND

As a leading cause of disability with a high societal and economic cost, it is crucial to better understand risk factors of neck pain and surgical complications. Getting subject-specific external loading is essential for quantifying muscle forces and joint loads but it requires exertion trials and load cells which are uncommon in clinical settings.

METHODS

This paper presents a method to compute the gravitational loading at four levels of the cervical spine (C3C4, C4C5, C5C6, C6C7) in neutral standing position from biplanar radiographs exclusively. The resulting load was decomposed in local disc frames and its components were used to compare different populations: 118 asymptomatic subjects and 46 patients before and after surgery (anterior cervical discectomy and fusion or total disc replacement). Comparisons were performed at C6C7 and the upper level adjacent to surgery.

FINDINGS

Significant changes in gravitational loading were observed with age in healthy subjects as well as in patients after surgery and have been associated with changes in posture.

INTERPRETATION

This approach quantifies the influence of postural changes on gravitational loading on the cervical spine. It represents a simple way to obtain necessary input for muscle force quantification models in clinical routine and to use them for patient evaluation. The study of the subsequent subject-specific spinal loading could help further the understanding of cervical spine biomechanics, degeneration mechanisms and complications following surgery.

Clinical Outcomes between Stand-Alone Zero-Profile Spacers and Cervical Plate with Cage Fixation for Anterior Cervical Discectomy and Fusion: A Retrospective Analysis of 166 Patients

Stand-alone (SA) zero-profile implants are an alternative to cervical plating (CP) in anterior cervical discectomy and fusion (ACDF). In this study, we investigate differences in surgical outcomes between SA and CP in ACDF. We conducted a retrospective analysis of 166 patients with myelopathy and/or radiculopathy who had ACDF with SA or CP from Jan 2013-Dec 2016. We measured surgical outcomes including Bazaz dysphagia score at 3 months, Nurick grade at last follow-up, and length of hospital stay. 166 patients (92F/74M) were reviewed. 92 presented with radiculopathy (55%), 37 with myelopathy (22%), and 37 with myeloradiculopathy (22%). The average operative time with CP was longer than SA (194 ± 69 vs. 126 ± 46 min) (p < 0.001), as was the average length of hospital stay (2.1 ± 2 vs. 1.5 ± 1 days) (p = 0.006). At 3 months, 82 patients (49.4%) had a follow-up for dysphagia, with 3 patients reporting mild dysphagia and none reporting moderate or severe dysphagia. Nurick grade at last follow-up for the myelopathy and myeloradiculopathy cohorts improved in 63 patients (85%). Prolonged length of stay was associated with reduced odds of having an optimal outcome by 0.50 (CI = 0.35-0.85, p = 0.003). Overall, we demonstrate that there is no significant difference in neurological outcome or rates of dysphagia between SA and CP, and that both lead to overall improvement of symptoms based on Nurick grading. However, we also show that the SA group has shorter length of hospital stay and operative time compared to CP.

Pseudarthrosis rate following anterior cervical discectomy with fusion using an allograft cellular bone matrix: a multi-institutional analysis

OBJECTIVE

The use of osteobiologics, engineered materials designed to promote bone healing by enhancing bone growth, is becoming increasingly common for spinal fusion procedures, but the efficacy of some of these products is unclear. The authors performed a retrospective, multi-institutional study to investigate the clinical and radiographic characteristics of patients undergoing single-level anterior cervical discectomy with fusion performed using the osteobiologic agent Osteocel, an allograft mesenchymal stem cell matrix.

METHODS

The medical records across 3 medical centers and 12 spine surgeons were retrospectively queried for patients undergoing single-level anterior cervical discectomy and fusion (ACDF) with the use of Osteocel. Pseudarthrosis was determined based on CT or radiographic imaging of the cervical spine. Patients were determined to have radiographic pseudarthrosis if they met any of the following criteria: 1) lack of bridging bone on CT obtained > 300 days postoperatively, 2) evidence of instrumentation failure, or 3) motion across the index level as seen on flexion-extension cervical spine radiographs. Univariate and multivariate analyses were then performed to identify independent preoperative or perioperative predictors of pseudarthrosis in this population.

RESULTS

A total of 326 patients met the inclusion criteria; 43 (13.2%) patients met criteria for pseudarthrosis, of whom 15 (34.9%) underwent revision surgery. There were no significant differences between patients with and those without pseudarthrosis, respectively, for patient age (54.1 vs 53.8 years), sex (34.9% vs 47.4% male), race, prior cervical spine surgery (37.2% vs 33.6%), tobacco abuse (16.3% vs 14.5%), chronic kidney disease (2.3% vs 2.8%), and diabetes (18.6% vs 14.5%) (p > 0.05). Presence of osteopenia or osteoporosis (16.3% vs 3.5%) was associated with pseudarthrosis (p < 0.001). Implant type was also significantly associated with pseudarthrosis, with a 16.4% rate of pseudarthrosis for patients with polyetherethereketone (PEEK) implants versus 8.4% for patients with allograft implants (p = 0.04). Average lengths of follow-up were 27.6 and 23.8 months for patients with and those without pseudarthrosis, respectively. Multivariate analysis demonstrated osteopenia or osteoporosis (OR 4.97, 95% CI 1.51-16.4, p < 0.01) and usage of PEEK implant (OR 2.24, 95% CI 1.04-4.83, p = 0.04) as independent predictors of pseudarthrosis.

CONCLUSIONS

In patients who underwent single-level ACDF, rates of pseudarthrosis associated with the use of the osteobiologic agent Osteocel are higher than the literature-reported rates associated with the use of alternative osteobiologics. This is especially true when Osteocel is combined with a PEEK implant.

Crossing the cervicothoracic junction in complex pediatric deformity using anterior cervical discectomy and fusion: a case series

PURPOSE

Proximal instrumentation failure is a challenge in posterior spinal fusions (PSFs) crossing the cervicothoracic junction. High rates of proximal junctional kyphosis (PJK) and loss of fixation have been reported. In this single-center retrospective cohort study, we evaluate the utility of anterior cervical discectomy and fusion (ACDF) in addition to traditional PSF crossing the cervicothoracic junction in order to mitigate implant-related complications.

METHODS

All patients who underwent PSF across the cervicothoracic junction with ACDF with 2 years of follow-up data were reviewed. We analyzed clinical, surgical, and radiographic measures such as operative details, presence of PJK, complications, instrumentation migration, curve angles, and vertebral translation. Measurements were compared statistically using paired samples t-tests.

RESULTS

Ten patients (6 girls, 4 boys) met inclusion criteria with a mean age at surgery of 12.8 ± 3.3 years and follow-up of 3.38 ± 0.9 years. All patients underwent ACDF (range 1-3 levels), and 8 (80%) underwent traction. The average number of levels fused posteriorly was 16.7 ± 4.7 and anteriorly was 2.4 ± 0.7. The major coronal curve averaged 48.8 ± 34.7° preoperatively and 23.3±13.3° postoperatively (p = 0.028). The average major sagittal curve was 83.5 ± 24.2° preoperatively, resolving to 53.9 ± 25.5° (p=0.001). One patient suffered rod breakage at T7, and another developed symptomatic PJK 19 months postoperatively.

CONCLUSION

Our data suggest that ACDF procedures added to PSFs crossing the cervicothoracic junction offer promise for reducing risk for instrumentation-related complications. ACDF also significantly helps improve and maintain both coronal and sagittal correction over 2 years.

LEVEL OF EVIDENCE

4.

Anterior Cervical Arthrodesis With Polyetheretherketone Spacers: What is the Role of the Grafting Material?

STUDY DESIGN

This was a retrospective study of 2 surgeons' use of a single polyetheretherketone (PEEK) device.

OBJECTIVE

Our objective was to investigate the fusion adjunct placed within PEEK devices to examine the likelihood of an arthrodesis, regardless of the PEEK interbody device itself.

SUMMARY OF BACKGROUND DATA

The effectiveness of PEEK interbody devices in anterior cervical arthrodesis has been questioned.

METHODS

The authors retrospectively reviewed the results of 121 patients with demineralized bone matrix (DBM) and 96 with local autograft bone placed within identical PEEK devices for anterior cervical arthrodesis (from 2011 to 2018); 1 surgeon used DBM and another local autograft bone. Arthrodesis was determined independently by a surgeon and 2 blinded neuroradiologists.

RESULTS

For DBM versus autograft; mean age was 60 versus 61 years, smoking status 42.1% versus 31%, diabetes mellitus 18.2% versus 28%, mean body mass index 31 versus 30, and follow up averaged 17 months in both groups. For DBM versus autograft; a radiographic arthrodesis was observed in 22.3% versus 76% of patients. Refusion at the index level was required in 5.8% of the DBM and 0% of the autograft patients.

CONCLUSIONS

A PEEK interbody device filled with local autograft resulted in a higher radiographic fusion rate and a lower need for reoperation at the index level than an identical device filled with DBM. Caution is warranted in assigning fusion failure to the PEEK device alone in anterior cervical discectomy and fusion surgery.

Fivefold higher rate of pseudarthrosis with polyetheretherketone interbody device than with structural allograft used for 1-level anterior cervical discectomy and fusion

In BriefThe authors examined fusion rates after single-level anterior cervical discectomy and fusion, comparing use of a structural allograft with use of polyetheretherketone (PEEK) interbody devices packed with bone graft. The results demonstrate superior results of structural allograft in terms of arthrodesis rates and reoperation rates. Currently, reimbursement rates substantially favor the use of PEEK and other synthetic devices, which the authors believe should be changed based on the results of this study.

ACDF vs TDR for patients with cervical spondylosis - an 8 year follow up study

Background

ACDF has been considered as the gold standard in the treatment of single level cervical disk protrusion. However, it may cause adjacent level degeneration due to regional biomechanical changes. TDR has been applied with satisfactory results for over a decade, but there is no consensus if TDR is safer and more efficient than ACDF. The current study was carried out to compare the efficiency and safety of TDR and ACDF in the treatment of patients with single level cervical disk protrusion.

Methods

One hundred forty-five consecutive patients who underwent either TDR or ACDF in our center were included in the current study. Time of surgery, intraoperative blood loss, VAS arm and neck pain scores, ROM, ODI, SF36 and Patient satisfaction were compared before the surgery, after the surgery, and during follow up 1, 3, 5, 8 years after the surgery.

Results

The time of surgery was 64.6 ± 20.7 min in the ACDF group and 69.4 ± 19.3 min in the TDR group; intraoperative hemorrhage was 67.2 ± 14.3 ml in ACDF group and 70.7 ± 18.6 ml in TDR group. There were no significant differences between two groups concerning time of surgery and intraoperative blood loss. No differences were found concerning patient satisfaction between the two groups during the follow up (P > 0.05). Significant differences were found between the groups concerning VAS arm and neck pain scores, ROM, ODI and SF36 after the surgery and during the 8 year follow up.

Conclusion

TDR may be a more effective approach than ACDF for treating patients with single level cervical disk protrusion.

Keywords

Cervical disk herniation, ACDF, TDR, Retrospective study