Background and rationale {6a}
Cervical radiculopathy is a symptom complex consisting of arm pain, impaired sensory and motor function in the corresponding dermatomes and myotomes, and varying degrees of neck pain. The cause is often foraminal stenosis, which is secondary to degenerative disk disease with disk herniation (21.9%) and/or osteophyte formation from the uncovertebral or facet joints (68.4%) compressing the nerve in the root canal [
1,
2]. The incidence has been estimated at 83.2 per 100,000 inhabitants/year with a peak at 50–54 years. Men are affected more often than women (107.3 vs. 63.5 per 100,000/year). The most often afflicted nerve root is the C7 root (46.3%), followed by C6 root (17.6%) [
2].
The diagnosis is set by the typical history and findings, which often involves loss of sensory and motor function, and diminished deep tendon reflexes. The foraminal compression test is a provocation test for the affected nerve root. The head is extended and rotated towards the affected side. A positive response is when pain is reproduced by axial compression of the head. The clinical results must correlate with the findings of the neuroradiological examination, primarily the MRI but alternatively CT is used in cases where MRI cannot be performed, because of, claustrophobia, non-MRI-compatible pacemaker or dorsal column stimulator, or the presence of other metal objects that may cause damage tissue by shifting position under the exam [
3]. In ambiguous cases, neurophysiological examinations may also be valuable.
Spontaneous restitution is common; hence, non-surgical treatment is often the first choice. Non-operative treatment may consist of pain medications, a neck collar, and physiotherapy. Indications for surgery are failure off non-operative therapy, with no relieve if the pain after a period of a couple of months, or if complications occur, i.e., intractable pain, progressive paresis, or cervical myelopathy. In these cases, surgical intervention may result in a reliable improvement and enhanced quality of life [
4].
Theoretical advantages of anterior decompression and fusion (ACDF) are the direct removal of the pain-generating disk fragment or osteophyte compression applied to the nerve root. Drawbacks are the approach-related complications, such as injury to neurovascular or other structures, and pseudoarthrosis, which may occur in a number of cases. The most feared acute complication is a postoperative hematoma, which, if untreated, may rapidly lead to airway obstruction or compression of the spinal cord. This occurs with an incidence of 1%. The incidences of other known complications with ACDF are as follows: esophagus lesion 0.25% [
5], infection 0.1–1.6% [
6], injury to the recurrent laryngeal nerve 0.6–2.9% [
7], injury to the superior laryngeal nerve 0–1.25% [
8], injury to the hypoglossal nerve 0–1.28% [
9], vertebral artery injury 0.08% [
10], dural tear 0.5–3.7% [
11], spinal cord injury 0–0.24% [
12], Horner’s syndrome 0.06% [
13], brachial plexus injury 0.1% [
14], C5 palsy 0–2.5% [
15], and injury to the thoracic duct 0.08% [
16].
Other complications associated with the anterior approach include intermittent early dysphagia which in most cases resolves [
17]. In addition, adjacent segment disease (ASD) may occur, as spinal fusion has been blamed for increasing the incidence of degeneration in adjacent levels [
18]. 25.6% will develop ASD within 10 years after ACDF and 7.5% will need further surgery. However, the cause for ASD is controversial, as disk degeneration is an age-related process affecting all disks and ASD may be a normal progression of the degenerative process affecting the disk adjacent to the fusion [
19]. ACDF leads to clinical success in 83–91% of cases, with a reoperation incidence of 4–14% [
20,
21].
Theoretical advantages with posterior foraminotomy (PF) include the following: fewer vital structures can be injured during the primary procedure and the segment is left unfused perhaps decreasing the risk for ASD. A disadvantage is that the decompression is indirect, meaning that the compressing fragment or the osteophyte is not removed, but the nerve root is allowed to move away from it, as the “roof” of the foramen is opened.
Approach-related complications with PF are postoperative hematoma, which may compress the spinal cord, and C5 palsy [
15], where the exact pathophysiology is not fully understood.
Instability issues after partial facetectomy during PF may lead problems that require fusion, in general fusion after PF have rates of up to 5%. Recent retrospective studies of minimal invasive PF with over 1000 cases shown that a good level of decompression is achieved, i.e., to same or better NDI in comparison to ACDF [
22‐
32].
The incidence of ASD is 6.7% 10 years after one level of PF, with 3.2% requiring reoperation for ASD [
33]. The preserved motion may lead to restenosis as the degeneration continues with the risk of secondary surgery on the index level [
34]. PF will lead to clinical success in 64–96% with a reoperation incidence of 4–7% in retrospective cohort studies [
22‐
32,
35‐
37].
Both methods result in a high rate of clinical success with a low incidence of reoperations. However, there are no prospective controlled studies with a high level of evidence comparing the two approaches. High level of evidence from RCTs could improve treatment guidelines and recommendations for the surgical treatment off cervical radiculopathy [
38‐
41].