Anterior cervical decompression and fusion on neck range of motion, pain, and function: a prospective analysis

Full endoscopic laminotomy decompression versus anterior cervical discectomy and fusion for the treatment of single-segment cervical spinal stenosis: a retrospective, propensity score-matched study

OBJECTIVE

Anterior cervical discectomy and fusion (ACDF) is the standard procedure for the treatment of cervical spinal stenosis (CSS), but complications such as adjacent segment degeneration can seriously affect the long-term efficacy. Currently, posterior endoscopic surgery has been increasingly used in the clinical treatment of CSS. The aim of this study was to compare the clinical outcomes of single-segment CSS patients who underwent full endoscopic laminotomy decompression or ACDF.

METHODS

138 CSS patients who met the inclusion criteria from June 2018 to August 2020 were retrospectively analyzed and divided into endoscopic and ACDF groups. The propensity score matching (PSM) method was used to adjust the imbalanced confounding variables between the groups. Then, perioperative data were recorded and clinical outcomes were compared, including functional scores and imaging data. Functional scores included Visual Analog Scale of Arms (A-VAS) and Neck pain (N-VAS), Japanese Orthopedic Association score (JOA), Neck Disability Index (NDI), and imaging data included Disc Height Index (DHI), Cervical range of motion (ROM), and Ratio of grey scale (RVG).

RESULTS

After PSM, 84 patients were included in the study and followed for 24-30 months. The endoscopic group was significantly superior to the ACDF group in terms of operative time, intraoperative blood loss, incision length, and hospital stay (P < 0.001). Postoperative N-VAS, A-VAS, JOA, and NDI were significantly improved in both groups compared with the preoperative period (P < 0.001), and the endoscopic group showed better improvement at 7 days postoperatively (P < 0.05). The ROM changes of adjacent segments were significantly larger in the ACDF group at 12 months postoperatively and at the last follow-up (P < 0.05). The RVG of adjacent segments showed a decreasing trend, and the decrease was more marked in the ACDF group at last follow-up (P < 0.05). According to the modified MacNab criteria, the excellent and good rates in the endoscopic group and ACDF group were 90.48% and 88.10%, respectively, with no statistically significant difference (P > 0.05).

CONCLUSION

Full endoscopic laminotomy decompression is demonstrated to be an efficacious alternative technique to traditional ACDF for the treatment of single-segment CSS, with the advantages of less trauma, faster recovery, and less impact on cervical spine kinematics and adjacent segmental degeneration.

Comparison of clinical outcomes between sequestered cervical disk herniation and non-sequestered cervical disk herniation after anterior cervical decompression and fusion: a cohort study

BACKGROUND

The advantages of anterior cervical decompression and fusion (ACDF) were well published, while research on postoperative results in different subtypes of cervical disk herniation (CDH) still remains blank. This study aimed to explore the surgical outcome between sequestration and other types in CDH.

METHODS

This retrospective cohort study enrolled 108 patients treated with ACDF in our hospital. The participants were divided into two groups according to the existence of a sequestered disk. The Visual analog scale score, the Japanese Orthopedics Association (JOA) score and the Neck disability index score were used to evaluate postoperative outcome.

RESULTS

Significant improvements were observed in both groups at every viewpoint (P < 0.001). The mean JOA was 15.04 ± 1.26 in the sequestered disk group and 14.45 ± 1.43 in the non-sequestered disk group two months after the operation (P = 0.026 < 0.05). The improvement in JOA at two months after ACDF showed a significant difference: 46.58% ± 39.17% in the sequestered disk group and 33.39% ± 28.82% in the non-sequestered disk group (P = 0.047 < 0.05). Thirty-two patients in the sequestered disk group (64%) and 19 patients in the non-sequestered disk group (32.76%) presented with high signal intensity of the spinal cord on preoperative cervical T2-weighted MRI (P < 0.001).

CONCLUSIONS

Patients with sequestered cervical disks seemed to have a higher degree of symptom improvement two months after ACDF. CDH with a sequestered disk appears to be more likely to cause high signal intensity changes in the compressed cervical spine on T2-weighted MRI. We prefer early positive surgery in patients with sequestered cervical disks from the clinical point of view.

Recurrent spinal stenoses after implant removal: A case report

Introduction and importance

Cervical spinal stenoses is becoming more and more common due to the aging population. The degenerative changes in the spine including discopathy or spondylosis will constrict and narrow the spinal canal and the usual site for the stenoses is in the cervical and lumbar region. The mainstay of the treatment is surgical, however there still a controversy regarding which approach is the best for the patient with cervical stenoses.

Case presentation

In this case reports we present a case of 63-year-old male who came to our center due to weakness of arms and legs due to cervical spinal stenoses and underwent treatment after which the implant was removed, and the symptoms worsens.

Clinical discussion

We performed Anterior Cervical Discectomy and Fusion (ACDF) and insertion of a cages to stabilize the spine. ACDF associated with lower intraoperative blood loss, similar surgical duration, and complication rate compared with laminoplasty. From the radiological outcome, ACDF showed a better-preserved cervical lordosis, which could affects patient's quality of life.

Conclusion

ACDF is one of the viable methods for the treatment of the cervical stenoses with lower complication rate and good clinical outcomes.

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Cervical spinal stenoses is a common degenerative disease in aging population.

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There still a controversy regarding the best surgical approach for the patient.

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An option includes Anterior Cervical Discectomy and Fusion (ACDF).

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ACDF with insertion of cages provides less complication rate.

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ACDF with insertion of cages also result in better clinical outcomes.

Musculoskeletal pain in Parkinson's disease: a narrative review

The prevalence of musculoskeletal (MSK) pain in people with Parkinson's disease (PD) is higher than that of age-matched controls. In this review, we outline what is known about MSK pain in PD, focusing on the neck, shoulder, knee, hip and low back. We also compare what is known about MSK pain in PD to what is known in older adults without PD. Finally, we outline areas of for future research related to MSK pain in people with PD.

Subjective and Objective Change in Cervical Spine Mobility After Single-level Anterior Cervical Decompression and Fusion

STUDY DESIGN

Prospective, observational study.

OBJECTIVE

The aim of this study was to collect objective and especially subjective data on changes in cervical spine mobility after single-level anterior cervical decompression and fusion (ACDF) and to investigate the impact on quality of life and activities of daily living (ADLs).

SUMMARY OF BACKGROUND DATA

Although there are several studies dealing with the objective change in mobility after single-level ACDF, there are few data on how spondylodesis of a motion segment affects subjective restriction of cervical spine mobility.

METHODS

Patients undergoing first-time, single-level ACDF for a symptomatic spondylotic process were eligible. Data were collected before surgery, at 3-month, and 1-year follow-up. Patients were assessed via clinical scores (pain intensity, Short-Form 8 [SF-8], among others) and asked for impairment in ADLs due to restriction of cervical spine mobility. The subjective restriction was acquired by a five-step patient-reported score. The range of motion was measured by the CROM device.

RESULTS

Data of 97 patients could be evaluated. For pain scores and SF-8 there were significant improvements 3 months and 1 year after surgery (P < 0.001). The impairment for most ADLs improved 3 months after surgery and further after 1 year. The subjective restriction showed a significant improvement in general and for all single directions 1 year after surgery. In the objective measurements, a significantly higher total rotation could be found 1 year after surgery compared to preoperatively (101.6° ± 21.2 vs. 93.9° ± 23.4; P = 0.002). There were no significant differences in total flexion-extension and lateral flexion. Increasing age was a significant predictor for objective and subjective restriction.

CONCLUSION

The concern of many patients of being severely restricted in their cervical spine mobility after single-level ACDF can be denied. Objectively, the rotation even showed a significant improvement. Regarding the subjective restriction, which is more important for the patients, we found a significant improvement in general and for all directions of movement after surgery.Level of Evidence: 3.

Biomechanical Evaluation of a Novel S-Type, Dynamic Zero-Profile Cage Design for Anterior Cervical Discectomy and Fusion with Variations in Bone Graft Shape: A Finite Element Analysis

BACKGROUND

Variations in cage design, material, and graft shape can affect osteointegration and adjacent segment range of motion (ROM) and stress after anterior cervical discectomy and fusion (ACDF) surgery. This study aimed to evaluate the biomechanical properties of a novel dynamic cervical cage design in both titanium (Ti) and polyether ether ketone (PEEK) with variations in bone graft shape using a single level ACDF (FE) model.

METHODS

A 3-dimensional C3-C6 FE model was developed using computed tomography scan data from a healthy male subject. The novel S-shaped dynamic interbody fusion cage with a zero-profile fixation was inserted at the C4-C5 level with 4 different bone graft shapes (square, circular, rectangular, and elliptical). Changes in segmental ROM and maximum von Mises stresses at the fusion and adjacent segments were analyzed.

RESULTS

Both Ti and PEEK cages showed decreased ROM at the fusion and adjacent levels for all shapes of bone graft when compared with the intact spine model. The elliptical graft, for both Ti and PEEK cages, showed a lower percentage of reduction in segmental ROM at the fusion and adjacent levels (0%-5.6%) when compared with other graft shapes (0%-12%). Maximum stresses at the fusion level were lowest in Ti cage with elliptical graft (229.8-347.6 MPa) when compared with other shapes (241.2-476.2 MPa) in flexion, extension, and lateral bending. For the bone graft, maximum stresses were highest on the elliptical-shaped bone graft in flexion and extension in the Ti cage, and in flexion and lateral bending in the PEEK cage.

CONCLUSIONS

Both Ti and PEEK cages showed decreased ROM at the fusion and adjacent levels for all shapes of bone graft when compared with the intact spine model. In the Ti and PEEK dynamic cages, the elliptical shape bone graft showed decreased stress on the cage and increased stress on the bone graft. Further experimental and clinical studies are needed to confirm these encouraging biomechanical results of this novel dynamic, zero-profile fusion device with elliptical bone graft in ACDF surgery.

The Outcomes of Patients With Neck Pain Following ACDF: A Comparison of Patients With Radiculopathy, Myelopathy, or Mixed Symptomatology

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The goal of the present study was to determine whether neck pain responds differently to anterior cervical discectomy and fusion (ACDF) between patients with cervical radiculopathy and/or cervical myelopathy.

SUMMARY OF BACKGROUND DATA

Many patients who undergo ACDF because of radiculopathy/myelopathy also complain of neck pain. However, no studies have compared the response of significant neck pain to ACDF.

METHODS

Patients undergoing one to three-level primary ACDF for radiculopathy and/or myelopathy with significant (Visual Analogue Scale [VAS] ≥ 3) neck pain and a minimum of 1-year follow-up were included. Based on preoperative symptoms patients were split into groups for analysis: radiculopathy (R group), myelopathy (M group), or both (MR group). Groups were compared for differences in Health Related Quality of Life outcomes: Physical Component Score-12, Mental Component Score (MCS)-12, Neck Disability Index, VAS neck, and VAS arm pain.

RESULTS

Two hundred thirty-five patients met inclusion criteria. There were 117 patients in the R group, 53 in the M group, and 65 in the MR group. Preoperative VAS neck pain was found to be significantly higher in the R group versus M group (6.5 vs. 5.5; P = 0.046). Postoperatively, all cohorts experienced significant (P < 0.001) reduction in VAS neck pain, (ΔVAS neck; R group: -2.9, M: -2.5, MR: -2.5) with no significant differences between groups. However, myelopathic patients showed greater improvement in absolute MCS-12 scores (P = 0.011), RR (P = 0.006), and % minimum clinically important difference (P = 0.013) when compared with radiculopathy patients. This greater improvement remained following regression analysis (P = 0.025).

CONCLUSION

Patients with substantial preoperative neck pain experienced significant reduction in their neck pain, disability, and physical function following ACDF, whether treated for radiculopathy or myelopathy. However, in this study, only myelopathy patients had significant improvements in their mental function as represented by MCS improvements.

LEVEL OF EVIDENCE

3.

Comparison of Adjacent Segment Degeneration, Cervical Alignment, and Clinical Outcomes After One- and Multilevel Anterior Cervical Discectomy and Fusion

Objective

This study aimed to assess the influence of a fused segment on cervical range of motion (ROM) and adjacent segmental kinematics and determine whether increasing number of fusion levels causes accelerated adjacent segment degeneration (ASD) after anterior cervical discectomy and fusion (ACDF).

Methods

A total of 165 patients treated with ACDF were recruited for assessment, and they were divided into 3 groups based on the number of fusion levels. Radiological measurements and clinical outcomes included visual analogue scale (VAS) and Neck Disability Index (NDI) assessed preoperatively and at ≥2 years of follow-up.

Results

ASD occurred in 41 of 165 patients who underwent ACDF (1-level, 12 of 78 [15.38%]; 2-level, 14 of 49 [28.57%]; 3-level, 15 of 38 [39.47%]; p=0.015) at final follow-up (mean, 31.9 months). Significant differences were found in reduction of global ROM based on the number of fusion levels (p<0.001). The upper adjacent segment ROM increased over time (p=0.004); however, lower segment ROM did not. Three-level ACDF did not obtain greater amounts of lordosis than did 1- or 2-level ACDF (p=0.003). Postoperative neck VAS scores and NDI were significantly higher for 3-level ACDF than for 1- or 2-level ACDF (p=0.033 and p=0.001).

Conclusion

ASD occurred predominantly in multilevel cervical fusion, more frequently in the upper segment of the prior fusion and as the number of fusion levels increased. Patients who underwent multilevel fusion had greater reduction of global ROM and increased compensatory motion at the upper adjacent segment. Three-level ACDF did not appear to restore cervical lordosis significantly compared with 1- or 2-level arthrodesis.

Correlation of Clinical and Radiological Outcome After Anterior Cervical Discectomy and Fusion With a Polyetheretherketone Cage

Background

Anterior cervical discectomy and fusion (ACDF) with a polyetheretherketone (PEEK) cage is considered as the gold standard for patients with cervical disc disease. However, there are limited in vivo data on the impact of ACDF on the cervical kinematics and its association with patient-reported clinical outcomes. The purpose of this study was to investigate the impact of altered cervical sagittal alignment (cervical lordosis) and sagittal range of motion (ROM) on patients’ self-reported pain and functional disability, after ACDF with a PEEK cage.

Methods

We prospectively studied 74 patients, who underwent single-, or consecutive two-level ACDF with a PEEK interbody cage. The clinical outcomes were assessed by using the pain numeric rating scale (NRS) and the neck disability index (NDI). Radiological outcomes included cervical lordosis and C2-C7 sagittal ROM. The outcome measures were collected preoperatively, at the day of patients’ hospital discharge, and also at 6 and 12 months postoperatively.

Results

There was a statistically significant reduction of the NRS and NDI scores postoperatively at each time point (P < 0.005). Cervical lordosis and also ROM significantly reduced until the last follow-up (P < 0.005). There was significant positive correlation between NRS and NDI preoperatively, as well as at 6 and 12 months postoperatively (P < 0.005). In regard to the ROM and the NDI scores, there was no correlation preoperatively (P = 0.199) or postoperatively (6 months, P = 0.322; 12 months, P = 0.476). Additionally, there was no preoperative (P = 0.134) or postoperative (6 months, P = 0.772; 12 months, P = 0.335) correlation between the NDI scores and cervical lordosis.

Conclusions

In our study, reduction of cervical lordosis and sagittal ROM did not appear to significantly influence on patients’ self-reported disability. Such findings further highlight the greater role of pain level over the mechanical limitations of ACDF with a PEEK cage on patients’ own perceived recovery.

Reliability and validity of CODA motion analysis system for measuring cervical range of motion in patients with cervical spondylosis and anterior cervical fusion

The aim of the present study was to evaluate the reliability of the Cartesian Optoelectronic Dynamic Anthropometer (CODA) motion system in measuring the cervical range of motion (ROM) and verify the construct validity of the CODA motion system. A total of 26 patients with cervical spondylosis and 22 patients with anterior cervical fusion were enrolled and the CODA motion analysis system was used to measure the three-dimensional cervical ROM. Intra- and inter-rater reliability was assessed by interclass correlation coefficients (ICCs), standard error of measurement (SEm), Limits of Agreements (LOA) and minimal detectable change (MDC). Independent samples t-tests were performed to examine the differences of cervical ROM between cervical spondylosis and anterior cervical fusion patients. The results revealed that in the cervical spondylosis group, the reliability was almost perfect (intra-rater reliability: ICC, 0.87–0.95; LOA, −12.86–13.70; SEm, 2.97–4.58; inter-rater reliability: ICC, 0.84–0.95; LOA, −13.09–13.48; SEm, 3.13–4.32). In the anterior cervical fusion group, the reliability was high (intra-rater reliability: ICC, 0.88–0.97; LOA, −10.65–11.08; SEm, 2.10–3.77; inter-rater reliability: ICC, 0.86–0.96; LOA, −10.91–13.66; SEm, 2.20–4.45). The cervical ROM in the cervical spondylosis group was significantly higher than that in the anterior cervical fusion group in all directions except for left rotation. In conclusion, the CODA motion analysis system is highly reliable in measuring cervical ROM and the construct validity was verified, as the system was sufficiently sensitive to distinguish between the cervical spondylosis and anterior cervical fusion groups based on their ROM.

Tapentadol extended release for the management of chronic neck pain

Background

The role of opioids in the management of chronic neck pain is still poorly investigated. No data are available on tapentadol extended release (ER). In this article, we present 54 patients with moderate-to-severe chronic neck pain treated with tapentadol ER.

Patients and methods

Patients received tapentadol ER 100 mg/day; dosage was then adjusted according to clinical needs. The following parameters were recorded: pain; Douleur Neuropathique 4 score; Neck Disability Index score; range of motion; pain-associated sleep interference; quality of life (Short Form [36] Health Survey); Patient Global Impression of Change (PGIC); Clinician GIC; opioid-related adverse effects; and need for other analgesics.

Results

A total of 44 of 54 patients completed the 12-week observation. Tapentadol ER daily doses increased from 100 mg/day to a mean (standard deviation) dosage of 204.5 (102.8) mg/day at the final evaluation. Mean pain intensity at movement significantly decreased from baseline (8.1 [1.1]) to all time points (P<0.01). At baseline, 70% of patients presented a positive neuropathic component. This percentage dropped to 23% after 12 weeks. Tapentadol improved Neck Disability Index scores from 55.6 (18.6) at baseline to 19.7 (20.9) at the final evaluation (P<0.01). Tapentadol significantly improved neck range of motion in all three planes of motion, particularly in lateral flexion. Quality of life significantly improved in all Short Form (36) Health Survey subscales (P<0.01) and in both physical and mental status (P<0.01). Based on PGIC results, approximately 90% of patients rated their overall condition as much/very much improved. Tapentadol was well tolerated: no patients discontinued due to side effects. The use of other analgesics was reduced during the observed period.

Conclusion

Our results suggest that tapentadol ER, started at 100 mg/day, is effective and well tolerated in patients with moderate-to-severe chronic neck pain, including opioid-naïve subjects. Patients can expect a decrease in pain, an improvement in neck function, and a decrease in neuropathic symptoms.

Reliability and scientific use of a surgical planning software for anterior cervical discectomy and fusion (ACDF)

PURPOSE

Software-based planning of a spinal implant inheres in the promise of precision and superior results. The purpose of the study was to analyze the measurement reliability, prognostic value, and scientific use of a surgical planning software in patients receiving anterior cervical discectomy and fusion (ACDF).

METHODS

Lateral neutral, flexion, and extension radiographs of patients receiving tailored cages as suggested by the planning software were available for analysis. Differences of vertebral wedging angles and segmental height of all cervical segments were determined at different timepoints using intraclass correlation coefficients (ICC). Cervical lordosis (C2/C7), segmental heights, global, and segmental range of motion (ROM) were determined at different timepoints. Clinical and radiological variables were correlated 12 months after surgery.

RESULTS

282 radiographs of 35 patients with a mean age of 53.1 ± 12.0 years were analyzed. Measurement of segmental height was highly accurate with an ICC near to 1, but angle measurements showed low ICC values. Likewise, the ICCs of the prognosticated values were low. Postoperatively, there was a significant decrease of segmental height (p < 0.0001) and loss of C2/C7 ROM (p = 0.036). ROM of unfused segments also significantly decreased (p = 0.016). High NDI was associated with low subsidence rates.

CONCLUSIONS

The surgical planning software showed high accuracy in the measurement of height differences and lower accuracy values with angle measurements. Both the prognosticated height and angle values were arbitrary. Global ROM, ROM of the fused and intact segments, is restricted after ACDF.

Four-level anterior cervical discectomy and fusion for cervical spondylotic myelopathy

PURPOSE

To review the outcome of 32 consecutive patients who underwent 4-level anterior cervical discectomy and fusion (ACDF) with cages and plates and were followed up for at least 5 years.

METHODS

Records of 19 men and 13 women aged 48 to 69 years who underwent 4-level ACDF with cages and plates for myelopathy (n=11) or myeloradiculopathy (n=21) at C3 to C7 by a single surgeon and were followed up for a minimum of 5 years were reviewed. Clinical outcome was assessed using the visual analogue scale (VAS), Neck Disability Index (NDI), and modified Japanese Orthopaedic Association (JOA) score for pain or myelopathic symptoms. Radiographic evaluation included fusion rate, range of motion, cervical lordosis (C2-to-C7 Cobb angle), and disc height.

RESULTS

The mean follow-up was 66 months. All patients had good recovery of muscle strength and resolution of limb sensory disturbance, except for 4 who still had some numbness. The mean VAS for neck and arm pain improved from 14.2 to 6.84 (p=0.012); the mean NDI improved from 31.62 to 12.17 (p<0.01); and the mean JOA score improved from 10.1 to 13.9 (p=0.027). The mean percentage of recovery was 62.9. The mean Cobb angle improved from 10.24º to 1.28º (p=0.019); the mean disc height improved from 4.12 to 6.58 mm (p<0.01). 30 (94%) patients achieved solid fusion.

CONCLUSION

Multilevel ACDF using PEEK cages and plates is safe and effective for multilevel cervical spondylotic myelopathy and achieves satisfactory mid-term outcome.

Comparison of Cervical Kinematics, Pain, and Functional Disability Between Single- and Two-level Anterior Cervical Discectomy and Fusion

STUDY DESIGN

A prospective, time series design.

OBJECTIVE

The purpose of this study is two-fold: firstly, to investigate the impact of altered cervical alignment and range of motion (ROM) on patients' self-reported outcomes after anterior cervical discectomy and fusion (ACDF), and secondly, to comparatively differentiate the influence of single- and two-level ACDF on the cervical ROM and adjacent segmental kinematics up to 12-month postoperatively.

SUMMARY OF BACKGROUND DATA

ACDF is one of the most commonly employed surgical interventions to treat degenerative disc disease. However, there are limited in vivo data on the impact of ACDF on the cervical kinematics and its association with patient-reported clinical outcomes.

METHODS

Sixty-two patients (36 males; 55.63 ± 11.6 yrs) undergoing either a single- or consecutive two-level ACDF were recruited. The clinical outcomes were assessed with the Pain Visual Analogue Scale (VAS) and the Neck Disability Index (NDI). Radiological results included cervical lordosis, global C2-C7 ROM, ROM of the Functional Spinal Unit (FSU), and its adjacent segments. The outcome measures were collected preoperatively and then at 3, 6, and 12-month postoperatively.

RESULTS

A significant reduction of both VAS and NDI was found for both groups from the preoperative to 3-month period (P < 0.01). Pearson correlation revealed no significant correlation between global ROM with neither VAS (P = 0.667) nor NDI (P = 0.531). A significant reduction of global ROM was identified for the two-level ACDF group at 12 months (P = 0.017) but not for the single-level group. A significant interaction effect was identified for the upper adjacent segment ROM (P = 0.024) but not at the lower adjacent segment.

CONCLUSION

Current study utilized dynamic radiographs to comparatively evaluate the biomechanical impact of single- and two-level ACDF. The results highlighted that the two-level group demonstrated a greater reduction of global ROM coupled with an increased upper adjacent segmental compensatory motions that is independent of patient-perceived recovery.

LEVEL OF EVIDENCE

3.

Influence of the Number of Cervical Fusion Levels on Cervical Spine Motion and Health-Related Quality of Life

STUDY DESIGN

A retrospective study.

OBJECTIVE

To analyze the influence of the number of cervical fusion levels on total cervical motion and health-related quality of life (HRQoL) in patients with solid anterior cervical fusions (ACFs).

SUMMARY OF BACKGROUND DATA

Few studies have analyzed the degree to which cervical range of motion (ROM) and HRQoL are affected by the number of cervical fusion segments.

METHODS

We analyzed a cohort of patients who underwent ACF for degenerative disc disease. To assess the clinical outcomes and HRQoL, preoperative, 1- and 2-year postoperative neck and arm pain, visual-analogue scale, neck disability index, and short form-36 were analyzed. Radiographically, C2-7 and C0-2 ROM, C2-7 sagittal vertical axis (SVA), and Kellgren grade of radiographic adjacent segment pathology (RASP) were evaluated.

RESULTS

A total of 105 patients (M:F = 46:59, mean age of 51.4 yr) were enrolled. There were 36 patients who underwent single-level ACF (group 1), 41 patients who had a double level ACF (group 2), and 28 patients who underwent ACF involving 3 or more levels (group 3). There was no decrease in C2-7 motion in group 1, a mean 7-degree decrease in group 2, a mean 18-degree decrease in those who underwent a 3-level ACF, and a mean 22-degree decrease after 4-level ACF. The grade of RASP was not influenced by the number of fusion levels. All HRQoL parameters showed no significant correlation between number of fusion levels, cervical ROM, and SVA.

CONCLUSION

Single-level ACF showed no decrease in total cervical motion; multilevel ACF decreased cervical motion by a mean of 7.8 degrees per segment of fusion. Progression of RASP showed no correlation with the number of fusion levels. HRQoLs were not influenced by the number of fusion levels, cervical ROM, or SVA after solid ACF.

LEVEL OF EVIDENCE

3.

Differential segmental motion contribution of single- and two-level anterior cervical discectomy and fusion

PURPOSE

To determine and compare the biomechanical effects of single- and two-level anterior cervical decompression and fusion (ACDF) on the re-distribution of the segmental contribution to total cervical range of motion (ROM) in a prospective longitudinal design.

METHODS

Fifty-one patients undergoing either a single- or two-level ACDF due to cervical disc disease were recruited. Functional radiographs were taken preoperatively and then at 3, 6 and 12-month follow-ups. Global ROM of C2-C7, ROM of the treated functional spinal unit (FSU) and the superior and inferior segmental ROMs were then measured. The relative contribution from the FSU and each of the adjacent segments to total cervical ROM were compared pre- and post-operatively within and between the two groups at each of the time points.

RESULTS

Single-level ACDF patients demonstrated a significantly greater total cervical ROM at 6 and 12 months compared with the two-level ACDF group (p = 0.021 and 0.045, respectively). A significantly greater contribution from the FSU to the total ROM was found at 3 months in the two-level ACDF group (p = 0.016), but the greater contribution shifted to the superior adjacent segment at 6 and 12 months (p = 0.025 and 0.046). The two-level ACDF group did not demonstrate a significant difference at 3 months (p = 0.087), but a significant increase in contribution was found at 6 and 12 months (p < 0.01).

CONCLUSIONS

Single-level ACDF maintains and restores a more physiological re-distribution of segmental contribution of ROM compared with two-level ACDF, which required longer time to achieve stable FSU immobilization and coupled with significantly increased superior segment contribution.