Atypical Symptoms of Cervical Spondylosis: Is Anterior Cervical Discectomy and Fusion Useful? - An Institutional Experience
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.317235
Source of Support: None, Conflict of Interest: None
Keywords: Anterior cervical discectomy and fusion, atypical symptoms, cervical spondylosisKey Message: ACDF might improve the atypical symptoms like vertigo, headache, nausea, vomiting and GI discomfort and hypertension in patients with cervical spondylosis. This highlights the additional benefit of this surgical approach and the need to explore its pathophysiological basis.
Cervical spondylosis is a chronic degenerative disease which results from progressive biomechanical stress and strain and can present as myelopathy, radiculopathy, axial cervical pain or the combination of the above. However, a proportion of patients having cervical spondylosis can complain about varying degrees of symptoms like vertigo, tinnitus, blurred vision, headache, nausea, vomiting, palpitations, hypertension and gastrointestinal (GI) discomfort. The pathophysiology behind the association of these clinical symptoms with cervical spondylosis is not very clearly known.
Anterior cervical discectomy and fusion (ACDF) is a commonly used approach for cervical spondylosis worldwide.,, However, the effect of anterior decompression on these atypical symptoms is yet to be explored.
In this retrospective study, we compared the severity and frequency of these symptoms before and after the surgery to investigate the effectiveness of ACDF in improving these symptoms in addition to myelopathy and/or radiculopathy. This in turn will also ascertain the association of these symptoms with cervical spondylosis.
This is a retrospective study of patients who underwent ACDF at All India Institute of Medical Sciences from January 2011 to December 2015. The study was approved by the institute ethics committee.
Patient inclusion criteria
Exclusion criteria of our study included:
Data regarding the severity and frequency of these symptoms was collected using a structured questionnaire [Table 1]. All patients were followed up at least 1 year after surgery or more frequently depending on symptoms. All patients were asked to report the severity and frequency of individual symptoms before the surgery and at last follow-up. As there is no standardized method to assess the severity and frequency of atypical symptoms, we (RS and KG) created a scale to objectively record the data [Table 2]. The data collected from phone interviews were entered in Microsoft excel by one reviewer (RS) and verified by the second reviewer (KG).
The severity and frequency of atypical symptoms before the surgery and at last follow-up were tabulated according to the scale. Considering that the data was non-parametric and paired, Wilcoxon signed rank test was used to assess the significance of changes in atypical symptoms. Preoperative values were compared with those obtained at last follow up. Profile plots were made for each symptom to better visualize the trends over the course of follow-up. All analyses were conducted using Microsoft Excel 2016 and IBM SPSS Statistics Version 20.
A total of 467 patients underwent ACDF for cervical spondylosis during the study period, out of which 358 patients were interviewed telephonically. Ninety-nine patients out of 358 met the eligibility criteria and were included in the final analysis. There were 80 (80.8%) male and 19 (19.2%) female patients. The mean age was 49.3 years (range: 17-68 years). The mean duration of atypical symptoms before surgery was 18.6 months (range: 12-35 months). The mean duration of follow-up was 36.2 months (range: 12–50 months). The mean time to improvement in atypical symptoms was 10.2 months (range: 5- 18 months). Mean Preoperative mJOA was 10.94 ± 2.79 and mean postoperative mJOA was 13.41 ± 2.25. There was significant improvement in mean mJOA score following surgery (P < 0.001). Most common level of compression was C5-6 (55 patients) followed by C4-5 (30 patients). There was no significant association between levels of compression and atypical symptoms (P = 0.67). Twenty eight patients were diagnosed with radiculopathy, fifty-eight with myelopathy, and thirteen with both symptoms. We did not find any significant correlation between improvements in typical symptoms in relation to improvements in atypical symptoms (P = 0.981). PEEK (polyetheretherketone) cage used in 81.8% of the cases, and iliac crest graft was used in the remaining patients.
Distribution of atypical symptoms
The distribution of atypical symptoms has been illustrated in [Figure 1]. Out of ninety-nine patients, hypertension was recorded in 43 (43.4%), headache in 40 (40.4%), vertigo in 31 (31.3%), nausea in 24 (24.2%), vomiting in 21 (21.2%), GI discomfort in 17 (17.2%), tinnitus in 5 (5.1%), palpitation in 5 (5.1%) and blurred vision in 3 (3%) patients before ACDF.
Assessment of severity and frequency of symptoms
The severity and frequency of vertigo [Figure 2], headache [Figure 3], nausea [Figure 4], vomiting [Figure 5] and GI discomfort [Figure 6] significantly improved at the last follow-up (P < 0.001) compared to the preoperative period. However, the improvements in severity and frequency of tinnitus (P = 0.083), palpitation (P = 0.317) and blurring of vision (P = 1.00) were not significant as shown in [Figure 7].
Significant improvement (P = 0.001) was observed in severity of hypertension [Figure 8]. Out of the ninety-nine patients, 43 (43.4%) had hypertension in the pre-operative period. Nine patients out of these became normotensive after ACDF. In 8 patients, the severity decreased from 2 to 1. In 25 patients, the severity remained constant before and after surgery. In one patient, hypertension worsened in the postoperative period and there were 2 patients who developed hypertension in postoperative period and continued to be hypertensive on last follow up.
The clinical presentations of cervical spondylosis in the form of myelopathy and/or radiculopathy were initially described by Brain et al. in 1952. It is the most common etiology of cervical cord and root dysfunction in patients greater than 55 years of age. It is caused by the chronic biomechanical forces leading to non-inflammatory disc degeneration, facet joint osteoarthritis and pathological changes in posterior longitudinal ligament and ligamentum flavum.,
A significant proportion of patients with cervical spondylosis manifest symptoms which cannot be attributed to a specific etiology despite adequate imaging and pathologic studies. Such symptoms have been referred to as 'atypical'. Initial studies attributed the etiology to the vasoconstriction caused by posterior sympathetic nerves in the vertebrobasilar system leading to ischemia. Li et al. demonstrated the presence of postganglionic sympathetic fibers in cervical PLL using sucrose-phosphate-glyoxylic acid staining which may be the site of origin of such symptoms. Gu et al. have reported abnormal autonomic discharges in middle cervical ganglion when posterior longitudinal ligament (PLL) was subjected to chronic compression.
Some authors have referred to these symptoms as cervical vertigo or cervical angina. In 1955, Ryan and Cope proposed that abnormal input to the vestibular nucleus from damaged joint receptors in the upper cervical region could result in 'cervical vertigo'. Other possible etiologies reported include mechanical compression or flow alteration of the vertebral artery,, whiplash injury and cervical spine instability.,,,,
The role of ACDF in alleviating these atypical symptoms is yet to be defined. On reviewing the literature, we came across a few studies which had reported the effect of surgical interventions on atypical symptoms.,,,,,,, We have summarized the characteristics and results of these studies in comparison to the current study [Table 3].
As it is evident from the results that there was improvement in severity and frequency of most of the atypical symptoms after ACDF, we hypothesize that this extra benefit is probably due to decompression of PLL achieved after discectomy or by the removal of a part of PLL itself which blocks the sympathetic reflex causing these atypical symptoms. Similarly, Wang et al. has also reported that removal of PLL or stabilization of the cervical segments to reduce irritation of PLL, can eliminate sympathetic symptoms. However, Sun et al. have reported that atypical symptoms of cervical spondylosis could be significantly relieved by double-door laminoplasty, suggesting that PLL may not be the only site responsible for these symptoms. Another study by the same group demonstrated that ACDF, total disc replacement and open door laminoplasty, all can significantly alleviate headache in patients with cervical spondylosis and no surgical technique was found to be better than the other in this respect. These findings have spurted an alternative hypothesis that compression of the spinal cord itself may be the etiology behind some of these symptoms.
We would like to point out that all of our patients were optimized medically before subjecting them to surgery and these symptoms were refractory to best medical care. The indication of ACDF was not atypical symptoms per se, but typical symptoms of cervical spondylosis,,, with improvement in atypical symptoms as an additional benefit. Whether or not persistent atypical symptoms merit surgical intervention is not a question that can be answered with our study and we acknowledge the possibility of placebo effect. Though we did not find any significant correlation between improvements in typical symptoms in relation to improvements in atypical symptoms in the current study, a prospective study is needed to establish this more rigorously. At out institute, PLL is removed in all cases with degenerative cervical spondylosis but the retrospective study design precludes us from having a uniform surgical procedure done in all patients so as to establish the cause and effect relationship between removal of PLL and improvement in atypical symptoms.
Though initial results of our study has been encouraging, there is a need for long term follow up of patients following ACDF as treatment results may change on long term follow up. As the possible pathophysiology of these symptoms is still debated, there is a need for further research to understand anatomic and molecular basis of this phenomenon.
ACDF for cervical spondylosis can result in improvement in atypical sypmtoms like vertigo, nausea, vomiting, headache and GI discomfort. This study highlights the possible additional benefit of this surgical approach and the need to explore pathophysiological basis for such atypical symptoms in cervical spondylosis.
We are really thankful to the department of Biostatistics, AIIMS, New Delhi for prooviding assistance in statistical analysis and meta-analysis.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3]