A prospective functional outcome of stand-alone cage in cervical disc prolapses following discectomy

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INTRODUCTION
hen dealing with cervical degenerative disease that has resulted in chronic radiculopathy or myelopathy, anterior cervical decompression, and fusion (ACDF) is the main therapy option.Bagby first utilized his nowstandard solo cage in 1988.Standalone cage concepts were created to combat the problems with plating ACDF, and positive results with a low incidence of dysphagia have been recorded (1).Patients undergoing current treatments, such as anterior cervical plating, are at risk for problems such as screw loosening, esophageal damage, dysphagia, paralysis of the recurrent laryngeal nerve, and extended surgical time (2).To prevent plate related complications, use of stand-alone cage has been advocated.
The purpose of this study was to establish the usefulness of stand-alone cage, by evaluating the clinical and radiological results.We hypothesized that self-locking-standalone cage has a better clinical and radiological outcome in patients with cervical disc prolapse and disc degenerative disease following discectomy.The Aim of this study was to assess the functional and radiological outcomes in stand-alone cage in cervical disc prolapse following discectomy.
The objectives of the present study were to evaluate pain and health-related quality of life in patients treated with stand-alone cage and to evaluate pre-operative and post-operative clinical and radiological evaluation.

METHODOLOGY
This is a prospective study conducted on the patients who underwent anterior cervical decompression and fusion using standalone cage in the department of Orthopedics, Justice KS Hegde Hospital, Deralakatte, Mangalore for a period of 18 months from 1 st January 2019 to 30 th June 2020.
Patients in the age group between 18 to 60 years with symptomatic cervical disc disease with cervical radiculopathy (including neck or arm pain and / or sensory / motor neurological deficit on clinical examination) were included in the study.12 cases subjected to the availability of patients satisfying inclusion criteria during the period of study were enrolled in the study.Patients with multiple level cervical disc degeneration, previous cervical spine surgery, inflammatory arthropathies, cervical vertebral fracture, cervical segmental instability, and active malignancy or infection were excluded from the study.

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Pre-operative assessment like clinical evaluation, radiological evaluation, visual analogue scoring of pain (VAS), neck disability index (NDI), and modified Japanese orthopedic association score (mJOA) were carried out.Post-operative assessment like clinical evaluation (pain assessment via scoring system was done on post-operative day 10), looked out for cage related complications such as subsidence and Kyphotic changes during follow up period at 3 rd and 6 th month post operatively by radiological evaluation.Radiological evaluation parameters like the overall cervical sagittal angle (CSA; C2-7 angle), segmental angle (SA) of the treated level, and interbody height (IBH) were measured.
The IBH was segmented in the front, in the center, and at the back, based on the vertical distance between pairs of adjacent vertebrae.Patients' outcomes were evaluated based on the presence or absence of subsidence, defined as a reduction in IBH by >2.5mm as measured by comparing lateral radiographs at any of the three sites or any of the treated levels.
Once information on the patient's discomfort and diagnostic imaging had been collected, descriptive statistics were utilized to provide a summary of the study's results.Undergraduates' claims of pain during medical procedures were analyzed using a t-test.The Wilcoxon signed-rank test was used if the data did not follow a normal distribution.If the p-value was less than 0.05, it was deemed statistically significant.

RESULTS
A test for data normality (the Shapiro-Wilk test) was performed.The data did not follow a normal distribution.Therefore, non-parametric tests were used.Out of the five patients in the neutral group who had anterior cervical decompression and fusion utilizing a solo cage, four (80%) were male and one (20%) was female.Out of 3 kyphosis subjects, 2 (66.7%) were females and 1 (33.3%) was male.Median age of neutral group and kyphosis was 45 and 34 respectively.
Median VAS score was higher in kyphosis group (9, 8, 6, and 4) as compared to neutral group (8, 7, 4, and 2) at pre-op, post-op at 10 days, 3 rd month and at 6 months respectively.Statistically significant difference was seen within the neutral group between all the time intervals except between 3 rd and 6 th month (p=0.102;Table 4) Whereas there was no significant difference seen for kyphosis group (Table 2).
Whereas there was no significant difference seen for kyphosis group (Fig. 1).(6).Additionally, according to Wu et al., (7).The longterm clinical prognosis is affected by whether a satisfactory cervical lordosis is restored or maintained following ACDF.Having a smaller cervical lordotic angle tends to foreshadow nearby degenerative alterations (8).
To evaluate neck and shoulder (radicular) pain before to surgery and at each follow-up, a 10-point visual analogue scale (VAS) was used, with 'no pain' at one end and "worst pain" at the other.We found that the average VAS score for arm pain after surgery was much lower than the score before surgery, Liu and colleagues' series found the same thing (9).
To the same extent as other clinical series with comparable sample sizes and durations of follow-up (10)(11)(12).After surgery, the NDI score significantly increased, as shown by our data.Our results, showing a substantial reduction in both neck and arm pain mean scores and the NDI mean scores, might be explained in this way.Multiple research projects support the idea that reducing NDI is related with less postoperative discomfort (13)(14)(15)(16) (22).Moreover, our results jived with those of numerous other clinical series studies already published in the literature.Most of our patients reported much less neck and arm discomfort upon hospital release, according to our most recent statistics.Furthermore, this impact persisted even after 18 months of follow-up.

Limitations
Whether we want to know if the results of this prospective research will hold up in the long run, we need further randomized controlled studies with longer follow-up periods.Additionally, the groups' fusion rates have not been analyzed.Finally, complications from employing a standalone cage for a multi-level ACDF need to be considered.These complications include neighboring segment degeneration, non-union, and corrective loss.

Fig. 1 :
Fig. 1: Comparison of NDI scores based on alignment using Mann-Whitney test

Table 1 :
Cross-tabulation of procedure and alignment

Table 2 :
Comparison of VAS scores based on alignment using Mann-Whitney test

Table 3 :
Comparison of Cobb's angle within the group using Wilcoxon sign test

Table 4 :
Comparison of VAS within the group using Wilcoxon sign test

Table 5 :
Comparison of NDI within the group using Wilcoxon sign test and the findings of our research corroborate this notion.Hassler and coworkers concluded that ACDF was a viable treatment option for degenerative cervical disc degeneration (21).Ali et al., authors of another study, performed ACDF on 129 patients, and found that 71.43 percent of them had great outcomes (5).Shiban et al., anterior cervical discectomy with fusion has a high fusion rate but a poor follow-up rate, according to the literature