Smith-Robinson procedure with and without Caspar plating as a treatment for cervical spondylotic myelopathy: A 26-year follow-up of 23 patients

The Frequency of Symptoms in Patients With a Diagnosis of Degenerative Cervical Myelopathy: Results of a Scoping Review

STUDY DESIGN

Delayed diagnosis of degenerative cervical myelopathy (DCM) is associated with reduced quality of life and greater disability. Developing diagnostic criteria for DCM has been identified as a top research priority.

OBJECTIVES

This scoping review aims to address the following questions: What is the diagnostic accuracy and frequency of clinical symptoms in patients with DCM?

METHODS

A scoping review was conducted using a database of all primary DCM studies published between 2005 and 2020. Studies were included if they (i) assessed the diagnostic accuracy of a symptom using an appropriate control group or (ii) reported the frequency of a symptom in a cohort of DCM patients.

RESULTS

This review identified three studies that discussed the diagnostic accuracy of various symptoms and included a control group. An additional 58 reported on the frequency of symptoms in a cohort of patients with DCM. The most frequent and sensitive symptoms in DCM include unspecified paresthesias (86%), hand numbness (82%) and hand paresthesias (79%). Neck and/or shoulder pain was present in 51% of patients with DCM, whereas a minority had back (19%) or lower extremity pain (10%). Bladder dysfunction was uncommon (38%) although more frequent than bowel (23%) and sexual impairment (4%). Gait impairment is also commonly seen in patients with DCM (72%).

CONCLUSION

Patients with DCM present with many different symptoms, most commonly sensorimotor impairment of the upper extremities, pain, bladder dysfunction and gait disturbance. If patients present with a combination of these symptoms, further neuroimaging is indicated to confirm the diagnosis of DCM.

The value of Clinical signs in the diagnosis of Degenerative Cervical Myelopathy - A Systematic review and Meta-analysis

STUDY DESIGN

Delayed diagnosis of degenerative cervical myelopathy (DCM) is likely due to a combination of its subtle symptoms, incomplete neurological assessments by clinicians and a lack of public and professional awareness. Diagnostic criteria for DCM will likely facilitate earlier referral for definitive management.

OBJECTIVES

This systematic review aims to determine (i) the diagnostic accuracy of various clinical signs and (ii) the association between clinical signs and disease severity in DCM?

METHODS

A search was performed to identify studies on adult patients that evaluated the diagnostic accuracy of a clinical sign used for diagnosing DCM. Studies were also included if they assessed the association between the presence of a clinical sign and disease severity. The QUADAS-2 tool was used to evaluate the risk of bias of individual studies.

RESULTS

This review identified eleven studies that used a control group to evaluate the diagnostic accuracy of various signs. An additional 61 articles reported on the frequency of clinical signs in a cohort of DCM patients. The most sensitive clinical tests for diagnosing DCM were the Tromner and hyperreflexia, whereas the most specific tests were the Babinski, Tromner, clonus and inverted supinator sign. Five studies evaluated the association between the presence of various clinical signs and disease severity. There was no definite association between Hoffmann sign, Babinski sign or hyperreflexia and disease severity.

CONCLUSION

The presence of clinical signs suggesting spinal cord compression should encourage health care professionals to pursue further investigation, such as neuroimaging to either confirm or refute a diagnosis of DCM.

Biomechanical analysis of the door-shaped titanium plate in single-level anterior cervical discectomy and fusion

BACKGROUND

Analyse and discuss the immediate stability of the cervical spine after anterior cervical discectomy and fusion using a door-shaped titanium plate and compare it with the traditional titanium plate, to provide biomechanical evidence for the rationality and effectiveness of the door-shaped titanium plate in clinical applications.

METHODS

Ten adult goat C4/5 vertebral bodies were obtained, and models were prepared using denture base resin. Biomechanical experiments were performed on the specimens before internal fixation. MTS was used to conduct non-destructive biomechanical loading tests in six directions, including flexion, extension, left-right bending, and left-right torsion, recording the range of motion (ROM) and neutral zone (NZ) of each specimen. The specimens were then randomly divided into two groups: the study group was fixed with a door-shaped titanium plate, and the control group was fixed with a traditional titanium plate. ROM and NZ in each direction were measured again. After measurements, both groups were subjected to 0.5 Hz torsion loading with a torque of 2 N m for a total of 3000 cycles, followed by measuring ROM and NZ in six directions once more.

RESULTS

Compared to before fixation, ROM and NZ in both groups significantly decreased in all six directions after fixation, with statistical significance (P < 0.05); after fixation, the study group showed slightly lower values for various mechanical reference parameters compared to the control group, with no statistical significance (P > 0.05); after 3000 torsional loads, both internal fixation groups showed increased ROM and NZ compared to after fixation but to a lower extent, and no screw or titanium plate loosening was observed. Compared to before fixation, the differences were still statistically significant (P < 0.05), with the study group having slightly lower ROM and NZ values in all directions compared to the control group, with no statistical significance (P > 0.05).

CONCLUSION

The door-shaped titanium plate exhibits mechanical properties similar to the traditional titanium plate in all directions, and its smaller size and simpler surgical operation can be used for anterior cervical endoscopic surgery, reducing surgical trauma. It is clinically feasible and deserves further research and promotion.

The role of neuronal plasticity in cervical spondylotic myelopathy surgery: functional assessment and prognostic implication

Cervical spondylotic myelopathy (CSM) is a degenerative disease representing the most common spinal cord disorder in the adult population. It is characterized by chronic compression leading to neurological dysfunction due to static and dynamic injury of the spinal cord in cervical spine. These insidious damage mechanisms can result in the reorganization of cortical and subcortical areas. The cerebral cortex can reorganize due to spinal cord injury and may play a role in preserving neurological function. To date, the gold standard treatment of cervical myelopathy is surgery, comprising anterior, posterior, and combined approaches. However, the complex physiologic recovery processes involving cortical and subcortical neural reorganization following surgery are still inadequately understood. It has been demonstrated that diffusion MRI and functional imaging and techniques, such as transcranial magnetic stimulation (TMS) or functional magnetic resonance imaging (fMRI), can provide new insights into the diagnosis and prognosis of CSM. This review aims to shed light on the state-of-the-art regarding the pattern of cortical and subcortical areas reorganization and recovery before and after surgery in CSM patients, underlighting the critical role of neuroplasticity.

Comparative Study between Caspar Cervical Retractor System and Traditional S Retractor in Application on Anterior Cervical Decompression and Fixation

OBJECTIVE

Although Caspar cervical retractor system (CCRS) is commonly utilized in anterior cervical decompression and fixation (ACDF), most urban hospitals still use both traditional S retractor and CCRS in conventional anterior cervical surgeries. Related data to evaluate the effect are required to be reported. The aim of this study is to compare the efficacy between using the traditional cervical S retractor and CCRS in anterior cervical decompression and fixation ACDF.

METHODS

The retrospective study that total 360 patients received ACDF using different retractors (traditional S retractor or CCRS) were enrolled in this study from January 2010 to January 2020. Width change rate of cervical prevertebral soft tissue, throat symptoms, and subjective experiences of the operating surgeons were evaluated by t-test or analysis of variance (ANOVA) respectively.

RESULTS

The width change rate of prevertebral soft tissue was significantly higher in the S retractor group than that of the CCRS group both in single segment group (40.9% vs 20.8%, P < 0.05) and double segments group (45.8% vs 25.2%; p < 0.05). In the three segments group, the width change rate of prevertebral soft tissue was higher in the S retractor group than that of the CCRS group, but with no statistical significance (27.3% vs 23.6%; P > 0.05). The incidence rates of dysphagia, dyspnea, and throat discomfort in the traditional S retractor group were significantly higher compared to the CCRS group (P < 0.05), while satisfactory rate of surgeon was higher in the CCRS group (P < 0.05). However, there was no correlation between anterior soft tissue rate and operative time (P > 0.05), as well as the width change rate of anterior soft tissue and the DNRS score (P > 0.05).

CONCLUSION

CCRS was superior compared to the traditional S retractor in reducing the postoperative complications and the postoperative fatigue of surgeon. Meanwhile, the width change rate of prevertebral soft tissue was not related to operative time and DNRS score.

Long-term follow-up MRI shows no hastening of adjacent segment degeneration following cervical disc arthroplasty

Cervical disc arthroplasty is an established procedure, but studies with data on long-term clinical outcome, reoperation for symptomatic adjacent segment degeneration (sASD), and degenerative changes based on MRI findings are rare. Thus, a file review was performed and patients with complete documentation of neurological status at preoperative, postoperative, 12 month, 3–4 years follow-up including surgical reports for reoperation with a minimum follow-up of 9 years were included. Final follow-up assessment included a physical examination, assessment of pain levels, Odoms criteria, Neck disability index. The degeneration of each cervical segment at preoperative and at final follow-up was assessed using an MRI. Forty-six out of 68 included patients participated, the mean follow-up was 11 (range 9–15) years, at which 71.7% of patients were free of arm pain, 52.2% of patients were free of neck pain, 63% of patients had no sensory dysfunction, and full motor strength was noted in 95.6% of patients. The clinical success rate was 76.1%, the mean NDI was 12%. Overall repeated procedure rate was 17%, the reoperation rate for sASD was 9%, and removal of CDA was performed in 4%. MRI showed progressive degeneration but no significant changes of SDI from preoperative to final follow-up.

Long-term functional outcome of surgical treatment for degenerative cervical myelopathy

OBJECTIVE

Degenerative cervical myelopathy (DCM) is a major global cause of spinal cord dysfunction. Surgical treatment is considered a safe and effective way to improve functional outcome, although information about long-term functional outcome remains scarce despite increasing longevity. The objective of this study was to describe functional outcome 10 years after surgery for DCM.

METHODS

A prospective observational cohort study was undertaken in a university-affiliated neurosurgery department. All patients who underwent surgery for DCM between 2008 and 2010 as part of the multicenter Cervical Spondylotic Myelopathy International trial were included. Participants were approached for additional virtual assessment 10 years after surgery. Functional outcome was assessed according to the modified Japanese Orthopaedic Association (mJOA; scores 0-18) score at baseline and 1, 2, and 10 years after surgery. The minimal clinically important difference was defined as 1-, 2-, or 3-point improvement for mild, moderate, and severe myelopathy, respectively. Outcome was considered durable when stabilization or improvement after 2 years was maintained at 10 years. Self-evaluated effect of surgery was assessed using a 4-point Likert-like scale. Demographic, clinical, and surgical data were compared between groups that worsened and improved or remained stable using descriptive statistics. Functional outcome was compared between various time points during follow-up with linear mixed models.

RESULTS

Of the 42 originally included patients, 37 participated at follow-up (11.9% loss to follow-up, 100% response rate). The mean patient age was 56.1 years, and 42.9% of patients were female. Surgical approaches were anterior (76.2%), posterior (21.4%), or posterior with fusion (2.4%). The mean follow-up was 10.8 years (range 10-12 years). The mean mJOA score increased significantly from 13.1 (SD 2.3) at baseline to 14.2 (SD 3.3) at 10 years (p = 0.01). A minimal clinically important difference was achieved in 54.1%, and stabilization of functional status was maintained in 75.0% in the long term. Patients who worsened were older (median 63 vs 52 years, p < 0.01) and had more comorbidities (70.0% vs 25.9%, p < 0.01). A beneficial effect of surgery was self-reported by 78.3% of patients.

CONCLUSIONS

Surgical treatment for DCM results in satisfactory improvement of functional outcome that is maintained at 10-year follow-up.

Young adults undergoing ACDF surgery exhibit decreased health-related quality of life in the long term in comparison to the general population

BACKGROUND CONTEXT

The leading surgical treatment of cervical radiculopathy is anterior cervical discectomy and fusion (ACDF). However, it has been suggested that ACDF procedures could lead to accelerated degeneration of the adjacent cervical discs (adjacent segment disease, or ASD) and the effect of ACDF surgery on neck symptoms and quality of life in the long term is not fully understood. Patients operated on at young ages generally have a long life expectancy and a long number of working years ahead of them. Thus, this patient group is of special interest when considering the accumulation of cervical problems due to possible ASD, the overall progressive nature of cervical degeneration in the long term, and their effects on related quality of life.

PURPOSE

Our goal was to study the health-related quality of life in the long-term follow-up after ACDF surgery in the young adult population between the ages of 18 and 40.

STUDY DESIGN

A retrospective cohort study with propensity matched controls.

PATIENT SAMPLE

All patients between 18 and 40 years of age at the time of the surgery who underwent ACDF due to degenerative cervical disease at Helsinki University Hospital between the years 1990 and 2005 who had filled in the quality of life questionnaires 12 to 28 years after the surgery (281 patients), and a propensity matched control cohort of the general population selected based on age, sex, and smoking status.

OUTCOME MEASURES

Quality of life measured by the EuroQol questionnaire (EQ-5D-3L and EQ-VAS).

METHODS

The medical records of all patients who underwent ACDF due to degenerative cervical disease at the age of 18 to 40 years at Helsinki University Hospital between 1990 and 2005 were analyzed retrospectively. The EuroQol questionnaire was sent to all patients whose contact information could be obtained (443 patients) at the end of the follow-up (median 17.5 years) to assess their current quality of life. A total of 281 patients returned the questionnaires and were included in this study. Quality of life was compared to that in the general Finnish population using a similar sized control cohort selected through propensity matching.

RESULTS

The patients who had undergone ACDF surgery reported significantly more problems than the general population cohort in three out of five dimensions that were assessed in the EQ-5D questionnaire, including mobility, usual activities, and pain/discomfort. Similarly, the overall EQ-5D-3L index calculated from the dimensional values was lower (0.74 vs. 0.83, p=.000), depicting a generally decreased health-related quality of life among patients. Spondylosis as a primary diagnosis, clinical myelopathy, and further cervical surgeries were associated with lower quality of life in the subgroup analyses of the patients. Similarly, in the EQ-VAS assessment, patient subgroups with spondylosis as a primary diagnosis, at least one reoperation, operation on more than one level, and clinical myelopathy were associated with lower scores and lower quality of life. The mean EQ-VAS score among patients was 73%. Regardless of the decreased health-related quality of life, there was no statistically significant difference in the concurrent employment status between the patient and control groups.

CONCLUSIONS

The health-related life quality measured by the EQ-5D-3L was lower in the patient population than in the general population. Patients had more problems with mobility and usual activities and more pain/discomfort. However, satisfaction with the surgery was very high, and there was no significant difference in employment status between the patients and the control population. Patients with spondylosis as a primary diagnosis had lower quality of life compared to patients with disc herniation. Also, clinical myelopathy and further cervical surgeries during follow-up were associated with lower quality of life in the subgroup analyses of the patients. It must also be kept in mind that we do not know what the situation could have been without surgery and with conservative treatment only.

Occurrence, Risk Factors, and Time Trends for Late Reoperations due to Degenerative Cervical Spine Disease: A Finnish National Register Study of 19 377 Patients Operated on Between 1999 and 2015

BACKGROUND

Surgery for degenerative cervical spine disease has escalated since the 1990s. Fusion has become the mainstay of surgery despite concerns regarding adjacent segment degeneration. The patient-specific trends in reoperations have not been studied previously.

OBJECTIVE

To analyze the occurrence, risk factors, and trends in reoperations in a long-term follow-up of all the patients operated for degenerative cervical spine disease in Finland between 1999 and 2015.

METHODS

The patients were retrospectively identified from the Hospital Discharge Registry. Reoperations were traced individually; only reoperations occurring >365 d after the primary operation were included. Time trends in reoperations and the risk factors were analyzed by regression analysis.

RESULTS

Of the 19 377 identified patients, 9.2% underwent a late reoperation at a median of 3.6 yr after the primary operation. The annual risk of reoperation was 2.4% at 2 yr, 6.6% at 5 yr, 11.1% at 10 yr, and 14.2% at 15 yr. Seventy-five percent of the late reoperations occurred within 6.5 yr of the primary operation. Foraminal stenosis, the anterior cervical decompression and fusion (ACDF) technique, male gender, weak opiate use, and young age were the most important risk factors for reoperation. There was no increase in the risk of reoperations over the follow-up period.

CONCLUSION

The risk of reoperation was stable between 1999 and 2015. The reoperation risk was highest during the first 6 postoperative years and then declined. Patients with foraminal stenosis had the highest risk of reoperation, especially when ACDF was performed.

Comparison of biomechanical performance of single-level triangular and quadrilateral profile anterior cervical plates

The quadrilateral anterior cervical plate (ACP) is used extensively in anterior cervical discectomy and fusion (ACDF) to reconstruct the stability of the cervical spine and prevent cage subsidence. However, there have been no comparison studies on the biomechanical performance of quadrilateral ACP and triangular ACP. The objective of this study is to investigate the functional outcomes of quadrilateral ACP and triangular ACP usage in ACDF surgery. In this study, a finite element model of intact C1-C7 segments was established and verified. Additionally, two implant systems were built; one using triangle anterior cervical plates (TACP) and another using quadrilateral orion anterior cervical plate (QACP). Both models were then compared in terms of their postoperative biomechanical performance, under normal and excessive motion. Compared to QACP, the peak stress of the TACP screws and plates occurred at 359.2 MPa and 97.2 MPa respectively and were the highest during over extension exercises. Alternately, compared to TACP, the endplate peak stress and the cage displacement of QACP were the largest at over extension, with values of 7.5 MPa and 1.2 mm, respectively. Finally, the average stress ratio of bone grafts in TACP was relatively high at 31.6%. In terms of biomechanical performance, TACP can share the load more flexibly and reduce the risks of cage subsidence and slippage but the screws have high peak stress value, thereby increasing the risk of screw slippage and fracture. This disadvantage must be considered when designing a TACP based implant for a potential patient.

Biomechanical effect of different plate-to-disc distance on surgical and adjacent segment in anterior cervical discectomy and fusion - a finite element analysis

Background

The plate-to-disc distance (PDD) is an important factor affecting the degeneration of adjacent segments after anterior cervical discectomy and fusion (ACDF). However, the most suitable PDD is controversial. This study examined the adjacent intervertebral disc stress, bone graft stress, titanium plate stress and screw stress to evaluate the biomechanical effect of different PDD on surgical segment and adjacent segment following C5/C6 ACDF.

Methods

We constructed 10 preoperative finite element models of intact C4–C7 segments and validated them in the present study. We simulated ACDF surgery based on the 10 intact models in software. We designed three different distance of plate-to-disc titanium plates: long PDD (10 mm), medium PDD (5 mm) and short PDD (0 mm). The changes in C4/C5 and C6/C7 intervertebral disc stress, bone graft stress, titanium plate stress and screw stress were analyzed.

Results

The von Mises stress of C4/C5 and C6/C7 intervertebral discs had no significant differences (P > 0.05) in three different PDD groups. Titanium plate stress increased as the PDD decreased. The bone graft stress and screws stress decreased as the PDD decreased. The maximum stress of each part occurred was mostly in the conditions of rotation and lateral bending.

Conclusions

The PDD has no effect on adjacent intervertebral disc stress, but it is an important factor that affecting the bone graft stress, titanium plate stress and screws stress after ACDF. Shorter PDD plate can provide better stability to reduce stress on screws and bone graft, which may be helpful to prevent cage subsidence, pseudarthrosis and instrument failure. This can serve as a reference for clinical choice of plate.

[Percutaneous endoscopic Key-Hole technology for treatment of paracentral cervical disc herniation]

OBJECTIVE

To investigate the effectiveness of percutaneous endoscopic posterior cervical Key-Hole fenestration decompression and nucleus pulposus extirpation in the treatment of paracentral cervical disc herniation.

METHODS

Between December 2015 and October 2018, 29 cases of paracentral cervical disc herniation were treated with percutaneous endoscopic posterior cervical Key-Hole fenestration decompression and nucleus pulposus extirpation. There were 16 males and 13 females, with an average age of 49.7 years (range, 39-78 years). The disease duration was 3.5-15.0 months (mean, 6.2 months). The herniated disc located at C 3, 4 in 2 cases, C 4, 5 in 5 cases, C 5, 6 in 9 cases, C 6, 7 in 12 cases, and C 7, T 1 in 1 case. The main symptoms were radiculopathy symptom. The operation time, intraoperative blood loss, hospital stay, and complications were observed and recorded. Visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, cervical range of motion (ROM), Macnab standard, and cervical segment stability were used to evaluate the efficacy and safety of the operation.

RESULTS

All patients were followed up 11-43 months, with an average of 19.4 months. The operation time was 67-89 minutes (mean, 73.3 minutes); the intraoperative blood loss was 18-30 mL (mean, 22.9 mL); the hospital stay was 5-10 days (mean, 7.3 days). All the incisions healed by first intention. There was 1 case of hypodynia and hyperalgesia in the affected limb after operation,1 case of decreased limb muscle strength. The VAS scores and JOA scores at each time point after operation were superior to those before operation ( P<0.05). There was no significant difference between the time points after operation ( P>0.05). At last follow-up, the effectiveness was rated according to the Macnab standard as excellent in 11 cases, good in 15 cases, fair in 2 cases, and bad in 1 case, with an excellent and good rate of 89.7%. The CT and MRI showed the decompression of spinal canal and nerve canal. There was no significant difference in cervical ROM between pre- and post-operation ( t=1.427, P=0.165), and no surgical segment instability occurred by X-ray films of flexion and extension of cervical vertebrae.

CONCLUSION

For the paracentral cervical disc herniation with simultaneous compression of nerve roots and spinal cord, percutaneous endoscopic posterior cervical Key-Hole fenestration decompression and nucleus pulposus extirpation has the advantages of small trauma, quick recovery, and satisfactory effectiveness, and can be used as a safe and effective minimally invasive procedure.

Comparison of cervical disc arthroplasty and anterior cervical discectomy and fusion for the treatment of cervical disc degenerative diseases on the basis of more than 60 months of follow-up: a systematic review and meta-analysis

BACKGROUND

This meta-analysis was designed to investigate the long-term efficacy and safety between cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) in treating cervical disc degenerative diseases (CDDDs).

METHODS

Literature search was performed on Pubmed, Embase, Cochrane Library, and Web of Science before Jan 2019. Surgical details, clinical outcomes, range of motion (ROM), complications, and reoperation rates between CDA and ACDF groups were compared and analyzed. A fixed- or random-effects model was applied based on different heterogeneity. STATA (Version 11.0) software was used to perform data analysis.

RESULTS

A total of 13 randomized controlled trial studies with more than 60 months of follow-up (mean 83.1 months) were enrolled in this meta-analysis. Pool results indicated that the CDA group exhibited significantly better outcomes in clinical scores (odds ratio [OR] = 1.54, 95% confidence interval [CI]: 1.15-2.08, p = 0.004) and preservation of ROM (mean difference = 1.77, 95% CI: 1.60-1.95, p < 0.001) than the ACDF group. Meanwhile, the incidence of adjacent segment disease (ASD) (OR = 0.51, 95% CI: 0.35-0.76, p = 0.001) and occurrence of reoperation (OR = 0.41, 95% CI: 0.25-0.69, p = 0.001) were lower in the CDA group than in the ACDF group.

CONCLUSIONS

At long-term follow-up, CDA showed better efficacy in terms of clinical outcomes, ROM, ASD, and reoperation than ACDF for treating CDDDs. However, our results require further validation in large-sample and high-quality studies.

Adjacent-level biomechanics after single-level anterior cervical interbody fusion with anchored zero-profile spacer versus cage-plate construct: a finite element study

BACKGROUND

The development of adjacent segment degeneration (ASD) following ACDF is well established. There is no analytical study related to effects of plate profile on the biomechanics of the adjacent-level after ACDF. This study aimed to test the effects of plate profile on the adjacent-level biomechanics after single-level anterior cervical discectomy and fusion (ACDF).

METHODS

A three-dimensional finite element model (FEM) of an intact C2-T1 segment was built and validated. From this intact model, two instrumentation models were constructed with the anchored zero-profile spacer or the standard plate-interbody spacer after a C5-C6 corpectomy and fusion. Motion patterns, the stresses in the disc, the endplate, and the facet joint at the levels cephalad and caudal to the fusion were assessed.

RESULTS

Compared with the normal condition, the biomechanical responses in the adjacent levels were increased after fusion. Relative to the intact model, the average increase of range of motion (ROM) and stresses in the endplate, the disc, and the facet of the zero-profile spacer fusion model were slightly lower than that of the standard plate-interbody spacer fusion model. The kinematics ROM and stress variations above fusion segment were larger than that below. The biomechanical features of the adjacent segment after fusion were most affected during extension.

CONCLUSIONS

The FE analysis indicated that plate profile may have an impact on the biomechanics of the adjacent-level after a single-level ACDF. The impact may be long-term and cumulative. The current findings may help explain the decreasing incidence of ASD complications in the patients using zero-profile spacer compared with the patients using cage and plate construct.

Is there a difference in the grade of degeneration at the cervical spine following anterior cervical fusion with respect to clinical outcome, diagnosis, and repeat procedure? An MRI study of 102 patients with a mean follow-up of 25 years

OBJECTIVE

There is currently no consensus on whether adjacent-segment degeneration (ASD), loss of disc height (DH), and loss of sagittal segmental angle (SSA) are due to anterior cervical discectomy and fusion (ACDF). The purpose of the present study was to assess the grade of segmental degeneration after ACDF and to analyze if there is a difference with respect to clinical outcome, diagnosis, and number of operated levels.

METHODS

A total of 102 patients who underwent ACDF with a minimum follow-up of 18 years were retrospectively identified. At final follow-up, the clinical outcome according to Odom's criteria, the Neck Disability Index (NDI), and reoperation for symptomatic ASD (sASD) was assessed. MRI was performed, and DH, SSA, and the segmental degeneration index (SDI, a 5-step grading system that includes disc signal intensity, anterior and posterior disc protrusion, narrowing of the disc space, and foraminal stenosis) were assessed for evaluation of the 2 adjacent and 4 adjoining segments to the ACDF. MRI findings were compared with respect to clinical outcome (NDI: 0%-20% vs > 20%; Odom's criteria: success vs no success), reoperation for sASD, initial diagnosis (cervical disc herniation [CDH] vs cervical spondylotic myelopathy [CSM] and spondylosis), and the number of operated levels (1 vs 2-4 levels).

RESULTS

The mean follow-up was 25 years (range 18-45 years), and the diagnosis was CDH in 74.5% of patients and CSM/spondylosis in 25.5%. At follow-up, the mean NDI was 12.4% (range 0%-36%), the clinical success rate was 87.3%, and the reoperation rate for sASD was 15.7%. For SDI, no significant differences were seen with respect to NDI, Odom's criteria, and sASD. Patients diagnosed with CDH had significantly more degeneration at the adjacent segments (cranial, p = 0.015; caudal, p = 0.017). Patients with a 2- to 4-level procedure had less degeneration at the caudal adjacent (p = 0.011) and proximal adjoining (p = 0.019) segments. Aside from a significantly lower DH at the proximal cranial adjoining segment in cases of CSM/spondylosis and without clinical success, no further differences were noted. The degree of SSA was not significantly different with respect to clinical outcome.

CONCLUSIONS

No significant differences were seen in the SDI grade and SSA with respect to clinical outcome. The SDI is higher after single-level ACDF and with the diagnosis of CDH. The DH was negligibly different with respect to clinical outcome, diagnosis, and number of operated levels.

Tissue discrimination by bioelectrical impedance during PLL resection in anterior decompression surgery for treatment of cervical spondylotic myelopathy

Background

The electrical properties of biological tissues differ depending on their physical properties. This study aimed to explore if bioelectrical impedance (modulus and phase) would discriminate tissues relevant to resection of the posterior longitudinal ligament (PLL) in anterior cervical decompression surgery.

Methods

PLL resection via an anterior approach was performed on the C4/5 segments in six mini-pigs. The bioelectrical impedance measurements were performed for two tissue groups (annulus fibrosus, endplate cartilage, sub-endplate cortical bone, and PLL; PLL, dura mater, spinal cord, and nerve root) using a novel probe and a precision inductance-capacitance-resistance meter. For each group, impedance was analyzed in terms of modulus and phase along a broad spectrum of frequencies (200–3000 kHz) using a nonparametric statistical analysis (Kruskal-Wallis).

Results

The analysis showed a clear difference among the tissues. The modulus and phase show the same changing trend with frequency and present lower values at higher frequencies. Among annulus fibrosus, endplate cartilage, sub-endplate cortical bone, and PLL, it was possible to discriminate each tissue at every frequency point, considering the phase (p < 0.05), while this was not always the case (i.e., annulus fibrosus vs PLL at frequency of 200 kHz, 400 kHz, and 3000 kHz, p > 0.05) for modulus. Among PLL, dura mater, spinal cord, and nerve root, for every comparison, a statistically significant difference was reported in the modulus, phase, or both (p < 0.05).

Conclusions

The results indicated the potential of bioelectrical impedance to provide real-time tissue differentiation and enhance safe PLL resection in anterior cervical decompression surgery, particularly in robot-assisted minimally invasive surgery (RMIS).

Is there an impact of cervical plating on the development of adjacent segment degeneration following Smith-Robinson procedure? A magnetic resonance imaging study of 84 patients with a 24-year follow-up

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) without and with cervical plating (ACDF+CP) are accepted surgical techniques for the treatment of degenerative cervical disc disorders. The effect of CP on the development of adjacent segment degeneration (ASD) remains unclear.

PURPOSE

To assess whether CP accelerates the degeneration of the adjacent and adjoining segments.

STUDY DESIGN/SETTING

This is an imaging cohort study.

PATIENT SAMPLE

Retrospectively, a total of 84 patients who underwent ACDF or ACDF+CP were identified. At final follow-up, an MRI was performed and evaluated in this study.

MATERIALS AND METHODS

An MRI of 84 patients who underwent ACDF (46 patients) and ACDF+PS (38 patients) was performed. The mean follow-up was 24 years (17-45 years). None of the patients had a repeat procedure in the cervical spine. The grade of degeneration of the segments adjacent and adjoining to the fusion was assessed via a five-step grading system (segmental degeneration index, or SDI) that includes disc signal intensity, anterior and posterior disc protrusion, narrowing of the disc space, and foraminal stenosis. Furthermore, the disc height (DH) and sagittal segmental angle (SSA) of fused segments were measured.

RESULTS

A significantly (p<.001) greater SDI was identified at the caudal adjacent segment following ACDF compared to ACDF+CP. No other significant differences were identified in patients following ACDF and ACDF+CP. Between 50% and 96% of all segments showed severe degenerative changes according to SDI. There was no significant difference in DH between the patients following ACDF and ACDF+CP. The SSA in patients who underwent ACDF+CP was significantly greater than in the ACDF patients (p=.002).

CONCLUSIONS

In this cohort of patients, cervical plating had no significant impact on segmental degeneration and decrease of DH in the adjacent and adjoining segments. ACDF+CP seem to preserve the lordotic alignment more with respect to the SSA than ACDF.

Is Two-level Cervical Disc Replacement More Cost-effective Than Anterior Cervical Discectomy and Fusion at 7 Years?

STUDY DESIGN

Cost-effectiveness analysis.

OBJECTIVE

To investigate 7-years cost-effectiveness of two-level cervical disc replacement (CDR) and anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

CDR and ACDF are both effective treatment strategies for managing degenerative conditions of the cervical spine. CDR has been shown to be a more-cost effective intervention in the short term, but the long-term cost-effectiveness has not been established.

METHODS

We analyzed 7-years follow-up data from the two-level Medtronic Prestige LP investigational device exemption study. Short-form 36 (SF-36) data were converted into health utility scores using the SF-6D algorithm. Costs were based on direct costs from the payer perspective, and effectiveness was measured as quality-adjusted life years (QALYs). The willingness-to-pay (WTP) threshold was set to $50,000/QALY. A probabilistic sensitivity analysis was conducted via Monte Carlo simulation.

RESULTS

Two-level CDR had a 7-year cost of $176,654.19, generated 4.65 QALYs, and had a cost-effectiveness ratio of $37,993.53/QALY. Two-level ACDF had a 7-year cost of $158,373.48, generated 4.44 QALYs, and had a cost-effectiveness ratio of $35,635.72. CDR was associated with an incremental cost of $18,280.71 and an incremental effectiveness of 0.21 QALYs, resulting in an incremental cost-effectiveness ratio (ICER) of $89,021.04, above the WTP threshold. Our Monte Carlo simulation demonstrated CDR would be chosen 46% of the time based on 10,000 simulations.

CONCLUSION

Two-level CDR and ACDF are both cost-effective procedures at 7-year follow up for treating degenerative conditions of the cervical spine. Based on an ICER of $89,021.04/QALY, we cannot conclude which treatment is the more cost-effective option at 7-years. CDR would be chosen 46% of the time based on 10,000 iterations of our Monte Carlo probabilistic sensitivity analysis.

LEVEL OF EVIDENCE

3.

Investigating the 7-Year Cost-Effectiveness of Single-Level Cervical Disc Replacement Compared to Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Cost-effectiveness analysis.

OBJECTIVES

To determine the 7-year cost-effectiveness of cervical disc replacement (CDR) and anterior cervical discectomy and fusion (ACDF).

METHODS

We analyzed 7-year Short Form-36 Health Survey data collected from the Prestige Cervical Disc investigational device exemption study (IDE). The SF-6D algorithm was used to convert this data into health state utilities. Costs were calculated from the payer perspective, and quality adjusted life years (QALYs) were used to represent effectiveness. A Markov transition-state model was used to evaluate the cost-effectiveness of single-level CDR versus ACDF, and a Monte Carlo simulation was performed to assess the probabilistic sensitivity of the model.

RESULTS

CDR generated a 7-year cost of $172 989 compared to a 7-year cost of $143 714 for ACDF. CDR generated 4.53 QALYs compared to 3.85 QALYs generated by ACDF. The cost-effectiveness ratio of CDR was $38 247/QALY, while the cost-effectiveness ratio of ACDF was $37 325/QALY. The incremental cost-effectiveness ratio of CDR was $43 522/QALY, under the willingness to pay threshold of $50 000/QALY. Our probabilistic sensitivity analysis demonstrated CDR would be chosen 56% of the time based on 10 000 simulations.

CONCLUSIONS

Single-level CDR and ACDF were both cost-effective strategies at 7 years for treating degenerative conditions of the cervical spine. Both the Markov simulation and the Monte Carlo simulation demonstrate CDR to be the more cost-effective strategy at 7 years. Continued analysis of IDE data should be performed to validate long-term cost-effectiveness of these treatment strategies.

Clinical outcome following anterior cervical discectomy and fusion with and without anterior cervical plating for the treatment of cervical disc herniation-a 25-year follow-up study

Extreme long-term clinical outcome studies following anterior cervical discectomy and fusion (ACDF) with an autologous iliac crest with and without Caspar plating (ACDF + CP) for the treatment of radiculopathy caused by cervical disc herniation (CDH) are extremely rare. Hospital records of patients who underwent ACDF or ACDF + CP for the treatment of CDH at least 17 years ago were reviewed. Information about diagnosis, surgery, pre- and postoperative clinical process, and repeated procedure was analyzed. At final follow-up, patients were reviewed with a standardized questionnaire including the current neurological status, Neck Disability Index (NDI), Odom's criteria, a modified EQ-5D, and limitations in quality of life. One hundred twenty-two patients with a mean follow-up of 25 years were evaluated. ACDF was performed in 80 and ACDF + CP in 42 patients, respectively. At final follow-up, 81.1% of patients were free of radicular pain and had no repeated procedure. According to Odom's criteria, 86.1% of good to excellent functional recovery was noted. The mean NDI and EQ-5D was 14% and 5 points, respectively. There was no significant difference in the assessed clinical outcome parameters between patients treated with ACDF and ACDF + CP. The rate for repeated procedure due to degenerative cervical disorders was 10.7 and 7.4% due to symptomatic adjacent segment disease with 25 years. ACDF and ACDF + CP achieved a high rate radicular pain relief (89.3%) and clinical success (86.1%) for the treatment of CDH within a 25 years follow-up. No statistical difference concerning clinical outcome and rate of repeated procedure was detected.