Anterior decompression for cervical spondylotic myelopathy

Novel Calcium Phosphate Promotes Interbody Bony Fusion in a Porcine Anterior Cervical Discectomy and Fusion Model

STUDY DESIGN

Experimental porcine anterior cervical discectomy and fusion (ACDF) model: a proof-of-concept study.

OBJECTIVE

The effect of monetite synthetic bone graft (SBG) containing calcium pyrophosphate and β-tricalcium phosphate on cervical spinal fusion in a noninstrumented two-level large animal model.

SUMMARY OF BACKGROUND DATA

ACDF is the gold standard surgical technique for the treatment of degenerative cervical spinal diseases. However, pseudarthrosis associated with increased patient morbidity occurs in ∼2.6% of the surgeries. SBG may enhance bony fusion and subsequently decrease the risk of pseudarthrosis. Recent studies on monetite-based SBGs for use in large cranial defects in humans have shown promising bone healing results, necessitating further investigation of their use in cervical spinal fusion.

MATERIALS AND METHODS

Four adult female Danish Göttingen minipigs received partial cervical anterior discectomy and intervertebral defects at an upper and lower level. One defect was filled with SBG, and the other was left empty. Bony fusion was evaluated using computed tomography (CT) at three-month intervals for 12 months. Fifteen months postsurgery, the animals were euthanized for further ex vivo qualitative histopathologic and micro-CT evaluations. Fusion rates were compared using the Fisher exact test at each time point.

RESULTS

Increased interbody bony fusion rates were observed at SBG levels (4/4) compared with control levels (0/4) evaluated by CT at 6 and 9 months postsurgery ( P =0.029). Fusion was observed at all SBG levels 12 months postsurgery and at only one control level. Histopathologic evaluation confirmed high-quality interbody bony fusion at all SBG levels and fusion by spondylosis at one control level.

CONCLUSION

This proof-of-concept study provides preliminary evidence of a novel, calcium pyrophosphate-containing, and β-tricalcium phosphate-containing monetite SBG that promotes bony fusion compared with a negative control in a clinically relevant porcine model of ACDF.

Pathophysiology of cervical myelopathy (Review)

Cervical myelopathy is a well-described medulla spinalis syndrome characterized by sensory disorders, such as pain, numbness, or paresthesia in the limbs, and motor disorders, such as muscle weakness, gait difficulties, spasticity, or hyperreflexia. If left untreated, cervical myelopathy can significantly affect the quality of life of patients, while in severe cases, it can cause disability or even quadriplegia. Cervical myelopathy is the final stage of spinal cord insult and can result from transgene dysplasias of the spinal cord, and acute or chronic injuries. Spondylosis is a common, multifactor cause of cervical myelopathy and affects various elements of the spine. The development of spondylotic changes in the spine is gradual during the patient's life and the symptoms are presented at a late stage, when significant damage has already been inflicted on the spinal cord. Spondylosis is widely considered a condition affecting the middle aged and elderly. Given the fact that the population is gradually becoming older, in the near future, clinicians may have to face an increased number of patients with spondylotic myelopathy.

Zero-Profile Anchored Spacer (ROI-C) in the Treatment of Cervical Adjacent Segment Disease

Background  Self-locking stand-alone cages have increasingly been used in anterior cervical discectomy and fusion (ACDF) cervical degenerative disc disease. We studied clinical and radiological outcomes of patients who underwent zero-profile anchored spacer (ROI-C)–assisted ACDF without anterior plate fixation in cervical adjacent segment disease.

Materials and Methods  Fifteen patients suffering from cervical adjacent segment disease with various symptoms, such as radiculopathy, myelopathy, or both, were retrospectively evaluated. The cervical adjacent segment disease was confirmed by plain radiographs and magnetic resonance imaging. The patients underwent radiological evaluation to assess cervical curvature, intervertebral height, fusion, and subsidence. Clinical assessment was graded using a visual analog scale, Modified Japanese Orthopedic Association score, and the Neck Disability Index.

Results  There were 19 levels of operation. Single-level ACDF was performed in 11 patients and two level in 4 patients. In the postoperative period, our study revealed significant improvement in the clinical outcome. The cervical curvature and intervertebral height were significantly improved at 12-months follow-up ( p  < 0.05). The fusion rate was 100%, whereas subsidence occurred in 5.3% but produced no symptoms. Of the 19 operated segment, 2 (5.3%) from 38 VerteBRIDGE plates had breakage. There was only one case of mild dysphagia, which resolved in less than 2 weeks.

Conclusion  This study indicates that zero-profile anchored spacer (ROI-C) in the treatment of cervical adjacent segment disease provides improvement of clinical outcomes, restoration of lordosis, high fusion rate, and low incidence of dysphagia. However, subsidence and breakage of VerteBRIDGE plate occurred in 5.3% cases, but did not cause clinical symptoms.

Surgical management of Diffuse Idiopathic Skeletal Hyperostosis (DISH) causing secondary dysphagia (Narrative review)

Objectives: To summarize the current evidence on surgical treatment for large bridging osteophytes of the anterior cervical spine from Diffuse Idiopathic Skeletal Hyperostosis (DISH). Overview of Literature: In the current review, the surgical treatment of secondary dysphagia from DISH was the most useful treatment. We propose a treatment algorithm for management of this condition because currently there are only case reports and retrospective studies available. Methods: Literature search was performed using the MeSH terms "Anterior Cervical Osteophyte," "Diffuse Idiopathic Skeletal Hyperostosis (DISH)," and "Dysphagia" and "Treatment" for articles published between January 2000 and February 2020. PubMed search identified 117 articles that met the initial screening criteria. Detailed analysis identified the 40 best matching articles, following which the full inclusion and exclusion criteria left 11 articles for this review. Results: Incidence of secondary dysphagia was associated with DISH in elderly patients (average 65 years). The major clinical findings were dysphagia or respiratory compromise, with the most common level of bridging osteophytes of the cervical spine at C3-C5. There were 10 articles on surgical treatment involving anterior cervical osteophytectomy without fusion, 1 for multilevel cervical oblique corpectomy, 1 for anterior cervical discectomy with fusion plus plate, and 1 for anterior cervical osteophytectomy with stand-alone PEEK cage or plus plate. All the cases resulted in significant improvement without recurrence, with only 1 case having post-operative complications. Follow-up duration was 3-70.3 months. Conclusions: Surgical intervention for anterior cervical osteophytectomy appears to result in improved outcomes. However, there could be disadvantages concerning cervical spine motion if cervical osteophytectomy with cervical discectomy and fusion (ACDF) plus plate system is done.

Pattern and Rate of Functional Recovery After Surgery for Cervical Spondylotic Myelopathy: Egyptian Prospective Study

OBJECTIVE

To study pattern and rate of neurological functional recovery after surgery for cervical spondylotic myelopathy (CSM).

METHODS

This prospective study comprised 25 patients with CSM who underwent surgical decompression at our institution. Upper limb, lower limb, and sphincter functions were assessed using the modified Japanese Orthopaedic Association score (mJOA). Assessment was done before the operation and at 1 month, 3 months, and 1 year after surgery.

RESULTS

The mJOA score did not significantly increase at 1 month after surgery (P = 0.051); however, increase in mJOA score was statistically significant at 3 and 1 year after surgery (P < 0.001 and P < 0.001, respectively). Upper limb motor dysfunction improved in 65% of patients, lower limb motor dysfunction improved in 52% of patients, upper limb sensory dysfunction improved in 48% of patients, and sphincter dysfunction improved in 14.2% of patients. There was a significant positive correlation between preoperative and postoperative mJOA score at 1 month, 3 months, and 1 year after surgery.

CONCLUSIONS

Minimal improvement occurred in the first month after CSM surgery to reach a peak at 3 months after surgery and steady improvement up to 1 year after surgery. Upper limbs recovered better and earlier than lower limbs and sphincter function. Preoperative severity of CSM is one of the main predictors of postoperative neurological outcome.

Graft Subsidence and Revision Rates Following Anterior Cervical Corpectomy: A Clinical Study Comparing Different Interbody Cages

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To assess the subsidence and revision rates associated with different interbody cages following anterior cervical corpectomy and reconstruction.

SUMMARY OF BACKGROUND DATA

Different interbody cages are currently used for surgical reconstruction of the anterior and middle columns of the spine following anterior cervical corpectomy. However, subsidence and delayed union/nonunion associated with allograft and cage reconstruction are common complications, which may require revision with instrumentation.

MATERIALS AND METHODS

We reviewed the cases of 75 patients who underwent cervical corpectomy and compared the radiographic graft subsidence and revision rates for fibula allograft, titanium mesh cage, titanium expandable cage, and carbon fiber cages. Subsidence was calculated by comparing the immediate postoperative lateral x-ray films to those obtained during follow-up visits.

RESULTS

The average graft subsidence was 3 mm and revision rate was 25% for fibula allograft versus 2.9 mm and 11.1%, 2.9 mm and 18.8% for titanium mesh cages and titanium expandable cages, respectively. The average graft subsidence for carbon fiber cages was 0.7 mm with no revision surgery in this subset.

CONCLUSIONS

Our findings suggest that subsidence and revision rates following anterior corpectomy and interbody fusion could be minimized with the use of a carbon fiber cage.

Anterior corpectomy versus posterior laminoplasty: is the risk of postoperative C-5 palsy different?

OBJECT

Both anterior cervical corpectomy and fusion (ACCF) and laminoplasty are effective treatments for selected cases of cervical stenosis. Postoperative C-5 palsies may occur with either anterior or posterior decompressive procedures; however, a direct comparison of C-5 palsy rates between the 2 approaches is not present in the literature. The authors sought to compare the C-5 palsy rate of ACCF versus laminoplasty.

METHODS

The authors conducted a retrospective review of 31 ACCF (at C-4 or C-5) and 31 instrumented laminoplasty cases performed to treat cervical stenosis. The demographics of the groups were similar except for age (ACCF group mean age 53 years vs laminoplasty group mean age 62 years, p = 0.002). The mean number of levels treated was greater in the laminoplasty cohort (3.87 levels) than in the ACCF cohort (2.74 levels, p < 0.001). The mean preoperative Nurick grade of the laminoplasty cohort (2.61) was higher than the mean preoperative Nurick grade of the ACCF cohort (1.10, p < 0.001).

RESULTS

The overall clinical follow-up rate was 100%. The mean overall clinical follow-up was 15 months. There were no significant differences in the estimated blood loss or length of stay between the 2 groups (p > 0.05). There was no statistical difference between the complication or reoperation rates between the 2 groups (p = 0.184 and p = 0.238). There were 2 C-5 nerve root pareses in each group. Three of the 4 patients recovered full deltoid function, and the fourth patient recovered nearly full deltoid function at final follow-up. There was no statistical difference in the rate of deltoid paresis (6.5%) between the 2 groups (p = 1).

CONCLUSIONS

Both ACCF and laminoplasty are effective treatments for patients with cervical stenosis. The authors found no difference in the rate of deltoid paresis between ACCF and laminoplasty to treat cervical stenosis.

A comparison of anterior cervical discectomy and corpectomy in patients with multilevel cervical spondylotic myelopathy

BACKGROUND

The optimal surgical approach for multilevel cervical spondylotic myelopathy (CSM) has not been defined, and the relative merits of multilevel anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy (2-level or skip 1-level corpectomy) and fusion (ACCF) remain controversial. However, few comparative studies have been conducted on these two surgical approaches.

METHODS

This study retrospectively reviewed the case histories of 120 patients that underwent surgical treatment for 3- or 4-level CSM from July 2003 to June 2008. One hundred and twenty patients (81 male and 39 female) of mean age 58.3±9.8 years (37-78) were included. The study compared perioperative parameters (blood loss, operation times), complications [surgery-related complications (CSF, hoarseness, epidural hematoma, C5-palsy, dysphagia), instrumentation and graft related complications (dislodgement, subsidence)], clinical parameters [Japanese Orthopedic Association (JOA) scores, Neck Dysfunciton Index (NDI) scores], and radiologic parameters (segmental lordosis, fusion rate).

RESULTS

At a minimum of 2-year follow-up, both ACDF and ACCF groups demonstrated a significant increase in the JOA scores (preoperatively 9.25±1.9 and 8.86±1.9, postoperatively 13.86±1.6 and 13.27±1.8, respectively), segmental lordosis (preoperatively 9.79±3.4 and 9.54±3.0, postoperatively 17.75±2.6 and 14.49±2.5, respectively) and NDI scores (preoperatively 12.56±3.0 and 12.21±3.4, postoperatively 3.44±1.7 and 5.68±2.6, respectively). Six patients (2 dislodgement, 4 subsidence) in ACCF group had instrumentation and graft related-complications and they had no obvious neurological symptoms without a second operation. Blood loss (102.81±51.3 and 149.05±74, respectively, P=0.000), NDI scores (P=0.000), and instrumentation and graft related-complications (P=0.032) were significantly lower in the ACDF group, whereas operation time (138.07±30.9 and 125.08±26.4, respectively, P=0.021) and segmental lordosis (P=0.000) were significantly greater in the ACDF group. Other parameters were not significantly different in the two groups.

CONCLUSIONS

Surgical managements of 3- or 4-level CSM by ACDF or ACCF showed no significant differences in terms of achieved clinical symptom improvements, with the exception of better postoperative NDI scores in ACDF. In addition, ACDF is better than ACCF in terms of blood loss, lordotic curvature improvement and instrumentation and graft related-complication rates, with the exception of operation times.

Neurological recovery after surgical decompression in patients with cervical spondylotic myelopathy - a prospective study

Cervical spondylotic myelopathy is a common clinical problem. No study has examined the pattern of neurological recovery after surgical decompression. We conducted a prospective study on the pattern of neurological recovery after surgical decompression in patients with cervical spondylotic myelopathy. Patients suffering from cervical spondylotic myelopathy and requiring surgical decompression from January 1995 to December 2000 were prospectively included. Upper limbs, lower limbs and sphincter functions were assessed using the Japanese Orthopaedic Association (JOA) score. Assessment was done before the operation, at 1 week, 2 weeks, 1 month, 3 months, 6 months, 1 year and then yearly after surgery. Results were analysed with the t-test. Differences with P-values less than 0.05 were regarded as statistically significant. Fifty-five patients were included. The average follow-up period was 53 months. Thirty-nine patients (71%) had neurological improvement after the operation with a mean recovery rate of 55%. The JOA score improved after surgery, reaching statistical significance at 3 months and a plateau at 6 months. Thirty-six patients (65%) had improvement of upper limb function. Twenty-four patients (44%) had improvement of lower limb function. Eleven patients (20%) had improvement of sphincter function. The recovery rate of upper limb function was 37%, of lower limb function was 23% and of sphincter function was 17%. Surgical decompression worked well in patients with cervical spondylotic myelopathy. Seventy-one percent of patients had neurological improvement after the operation. The neurological recovery reached a plateau at 6 months after the operation. The upper limb function had the best recovery, followed by lower limb and sphincter functions.

Anterior cervical interbody fusion with a titanium box cage: early radiological assessment of fusion and subsidence

BACKGROUND CONTEXT

The use of stand-alone cervical interbody cages in anterior cervical discectomy with fusion (ACDF) has become popular, but high subsidence rates have been reported in the literature.

PURPOSE

The authors present short-term radiological results of a titanium box cage with regard to fusion and subsidence. Reliable fusion and lack of subsidence may influence long-term clinical results. Early radiological data are necessary before implementation of this device on a larger scale can be accepted.

STUDY DESIGN/SETTING

Retrospective radiological quality assessment study.

PATIENT SAMPLE

ACDF using the titanium cage was performed in 71 consecutive patients at 106 levels. Diagnoses included cervical disc disease (57) and cervical spinal stenosis (14) after failed conservative treatment.

OUTCOME MEASURES

Subsidence and kyphosis were assessed on lateral cervical radiographs made directly postoperative and at 3- and 6-month follow-up. At 6-month follow-up, lateral flexion-extension radiographs were made to assess fusion.

METHODS

Subsidence of the cage was defined as a decrease in total vertical height of the two fused vertebral bodies as measured on the lateral cervical radiographs made 3 and 6 months postoperatively compared with the directly postoperative radiographs. Segmental kyphosis was measured as the angle between the posterior borders of the two vertebral bodies on the lateral radiograph.

RESULTS

No patients were lost to follow-up. Fusion was achieved after 6 months in all patients. At 3 and 6 months postoperative the same 10 cages (each in a different patient) had subsided. The C6-C7 level was significantly more frequently involved compared with all other levels. A segmental kyphotic alignment was observed in five patients at the C6-C7 level and in one patient at the C4-C5 level.

CONCLUSIONS

For patients with cervical disc disease, the high subsidence tendency of the cage into the end plate of predominantly C7 is a disturbing phenomenon found in this study. A modified cage design that improves and extends contact with the inferior surface could be expected to reduce subsidence into C7.

Intraoperative evaluation of bone decompression in anterior cervical spine surgery by three-dimensional fluoroscopy

Sufficient bone decompression of osteophytes is essential for functional long-term outcome in surgery for spondylotic cervical myelopathy. Postoperative CT scans clearly show that decompression is sometimes insufficient. Intraoperative CT scanning has been used to monitor sufficient decompression. Instead of standard intraoperative fluoroscopy, we used an isocentered three-dimensional (3D) fluoroscopy with 3D image reconstruction to evaluate the extent of bone decompression. From October 2003 to April 2004, we have used intraoperative 3D fluoroscopy on seven patients with anterior cervical spine surgery due to cervical spondylotic myelopathy. Five patients were operated on in one level, two patients had surgery in two segments. If surgery was performed in two levels or preoperative cinetic MRT showed cervical instability, internal plate fixation was done additionally. All patients were positioned on a radiolucent operating table, made of carbon fibers. Three-dimensional fluoroscopy was always performed before wound closure to evaluate sufficient bone removal. The scanning time was 120 s and the whole procedure from scanning to evaluation is approximately 5 min. In all patients we were able to evaluate the extent of bone decompression. Additionally, placement of cage, plates and screws can be evaluated intraoperatively. In one patient, 3D fluoroscopy showed insufficient decompression, especially on the right side. Further bone removal was performed before the end of the procedure. Intraoperative 3D fluoroscopy is a valuable tool for imaging bone decompression and implant location in anterior cervical spine surgery. The technique is safe, reliable and should help us to avoid incomplete decompression or misplacement of implants and therefore improve long-term functional outcome in cervical spine surgery in the future.