Learning Objectives: After participating in this CME activity, physicians should be better able to:
- Describe the incidence and clinical presentation of common spinal disorders in older patients.
- Select surgical candidates for common geriatric disorders in the cervical spine, including degenerative cervical myelopathy, cervical radiculopathy, and trauma.
Our society is rapidly aging, resulting in a progressive increase in the geriatric population to a higher proportion than has been seen before. The spinal axis can be significantly affected by aging in various ways and to varying extents, and thus age-related spine pathologies are commonly encountered in the clinical setting. Degenerative changes in the intervertebral discs, osteophytes, and ligaments and spinal instability due to facet joint arthritis all give rise to spinal canal stenosis, which then leads to cervical myelopathy and/or radiculopathy. In addition to these chronic pathologies, frailty in older patients makes them more susceptible to specific types of spinal injury, such as central cord syndrome and type II odontoid fracture.
Loss of function associated with these conditions in older patients can be devastating, and cost associated with treatment of these disorders is a significant economic burden to society. It is imperative for neurosurgeons to understand the state-of-art treatment guidelines for management of these commonly encountered disorders. The purpose of the present review article is to summarize the contemporary recommendations as to treatment strategies for these conditions in the aging cervical spine.
Degenerative Cervical Myelopathy
In 2015, Fehlings et al. introduced the concept of degenerative cervical myelopathy (DCM), which includes a spectrum of myelopathy caused by degenerative changes in the spinal axis. Cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament (OPLL) are the 2 major diagnoses commonly made in this category. DCM is the most prevalent cause of acquired spinal cord impairment in adults. Spinal cord compression occurs at varying levels of severity depending on the progression of degenerative changes in multiple components. One of the most commonly used measurement methods to assess the severity of myelopathic symptoms is the modified Japanese Orthopaedic Association (mJOA) score. It encompasses the assessment of hand dexterity, walking capability, and sensory function in the upper extremity and bladder function and rates neurologic function on a scale of 0 to 18. Fehlings et al. defined severity according to mJOA score as follows: a score of 15 or higher as mild, a score of 12 to 14 as moderate, and less than 12 as severe.
Treatment options are largely determined on the basis of severity of neurologic deficits. For mild myelopathy, it is common and acceptable to first use nonsurgical options to treat the condition. Nonsurgical options currently used in the management of DCM include structured physical therapy, spinal injection, immobilization by collars, and cervical traction. However, evidence for their effectiveness is still scarce. Kadanka et al. performed a small randomized controlled trial and did not find any superiority of surgical treatment over conservative management in patients with mild myelopathy. More recent systematic reviews concluded that the effectiveness might be greatly dependent on the individual. Our current recommendation is to offer surgical options when the patient does not react to an initial trial of conservative management and where progression of the myelopathy is observed.
For moderate to severe myelopathy, there is no evidence for conservative management, and surgery is considered the optimal treatment option. Given its progressive nature, early intervention should be sought as long as the patient is fit for surgery. The primary purpose of surgical intervention is to achieve sufficient spinal cord decompression and stabilization as needed to halt the progressive insult to spinal cord and optimize the environment for neurologic recovery. There are variable options for surgical approach. Anterior procedures include anterior cervical discectomy and fusion (ACDF), anterior cervical corpectomy and fusion (ACCF), and disc replacement, whereas posterior options include laminectomy with fusion and laminoplasty. Both anterior and posterior approaches have been well established. Approach is usually determined after imaging of the features that cause spinal cord compression, but it is also affected by patient demographics and the surgeon preference. Laminectomy without fusion is typically not used anymore, due to caution regarding postlaminectomy kyphosis. Apart from this, there is no solid evidence indicating an advantage of one specific approach over the other, although specific consideration might be necessary in some situations. For example, ACCF should be chosen instead of ACDF for anterior compression at vertebral body level, and OPLL with high occupancy ratio should be approached from the anterior side. Overall, surgeons need to balance out the risks and benefits associated with each procedure and discuss the pros and cons of the available surgical strategies with the patient.
Impact of age on neurologic recovery has been rigorously studied. In the AOSpine International study, Nakashima et al. revealed that neurologic recovery in older patients (≥ 65 years) was not equivalent to that in younger patients, and age was an independent predictor of surgical outcome in DCM. However, they also reported that patients older than 65 years still showed functionally significant improvement after surgical intervention, and old age should not preclude a surgical treatment if deemed appropriate.
The use of neuroprotective agents is a promising augmentation to surgical treatment. Riluzole, an anticonvulsant that functions as a sodium channel blocker, which has been approved for the treatment of amyotrophic lateral sclerosis, is known to attenuate the ischemia-related excitotoxicity in spinal cord injury. It has been shown to result in superior neurologic recovery, compared with the control group, in a phase I trial for traumatic spinal cord injury. Riluzole has shown encouraging results in a rodent model of DCM, and a multicenter double-blinded randomized controlled trial to investigate the potential neurologic benefits as a complementary strategy to surgical decompression is underway, led by Fehlings et al.
Cervical radiculopathy refers to nerve root pathology in the cervical spine. Compression usually occurs at the neural foramen. It can be caused by posterolateral disc herniation, but in the geriatric population degenerative spondylosis causes osteophyte formation from uncovertebral joints that impinge the nerve root, which is also aggravated by the loss of disc height. Commonly experienced symptoms include pain, numbness, and weakness of a dermatome or muscle group covered by a solitary nerve root, but it can also appear as multilevel radiculopathy. The surgical indications for cervical radiculopathy are not well established. However, several studies investigating the natural history of this condition have indicated that the recovery rate is quite high, and it is generally believed that cervical radiculopathy is a self-limiting disease. In light of this, nonsurgical treatment options are usually chosen as first line. These include structured physical therapy, spinal injection, immobilization by collars, and cervical traction. Given its benign history, evidence to support their effectiveness is scarce. However, there is evidence to suggest that corticosteroid injection to the nerve root (selective nerve root block) is useful as a diagnostic as well for temporary symptomatic relief. Injection should be performed to the specific nerve root that is the suspected cause under radiographic guidance, typically by an interventional radiologist. Even short-term pain relief would help surgeons understand the etiology and localize the pathology.
Because most spontaneous recovery of cervical radiculopathy has been reported to occur within 6 months, surgical intervention can be justified after that period depending on the patients' symptoms. Similar to the approach in cases of myelopathy, decompression can be obtained by either anterior or posterior approach. Anterior options include ACDF and disc replacement, and posterior laminoforaminotomy can also be selected. The advantages of posterior foraminotomy include the ease of accessing multilevel lesions and the nonfusion nature of the procedure, but it may not be the best option for decompression of osseous components from the front. A nerve root compression medial to the lateral edge of the dura is not amenable to a posterior approach and must be managed by an anterior surgical strategy.
In patients with clinical signs of cervical radiculopathy and radiographic evidence of spinal cord compression, the risk of developing myelopathy is known to be high. The patient should be advised and counseled regarding this, and early surgical intervention should be offered.
Although the incidence of high-energy trauma that leads to spinal cord injury is relatively rare in a geriatric population compared with younger populations, there are specific types of spinal trauma that are commonly encountered in older patients.
Central Cord Syndrome
Central cord syndrome (CCS) is defined by its clinical features in which patients experience more dysfunction in the upper extremities than in the lower extremities. Clinically, walking capability tends to be well maintained, but the vast majority of patients tend to develop debilitating upper extremity pain/paresthesia and/or weakness. What characterizes CCS in older populations is its mechanism of injury. This most often occurs when a patient falls onto his or her forehead and forces the cervical spine into hyperextension. Because hyperextension is applied on preexistent degenerative spinal canal stenosis, spinal cord contusion with buckling of the ligamentum flavum results in spinal cord injury. It can even occur without radiographic abnormalities (ie, fractures or dislocations). As this type of injury is recognized as mechanically stable, surgical decision-making is still controversial.
Historically, Schneider et al. reported spontaneous neurologic recovery in their case series and suboptimal outcomes after surgical decompression, and they concluded that surgery is contraindicated. Several contemporary studies have also reported favorable neurologic recovery after nonsurgical treatment for CCS. However, there is a clear trend toward a preference for surgical decompression, partly because surgical techniques have drastically evolved. Although comparative studies of nonsurgical and surgical treatments are rare, Stevens et al. reported better outcomes for surgically treated patients in neurologic recovery and length of hospital stay. Given increasing evidence supporting surgical intervention for CCS, we recommend limiting nonsurgical treatment to those who recover spontaneously while awaiting surgery, or when the surgical risk outweighs the benefit. Older age has been known to have a negative impact on neurologic recovery of CCS.
One of the controversies regarding surgical decision-making for CCS is the timing of decompression. For general spinal cord injury, there is now a consensus that early intervention is beneficial for better neurologic recovery. Several studies have also pointed out that early decompressive surgery for CCS within 24 hours is associated with better outcomes. However, the evidence needs to be carefully considered, because the neurologic behavior of CCS is different from other types of spinal cord injury as it has significant recovery potential. When early spontaneous recovery is observed, deferring any surgical option may be justified. Furthermore, medical optimization with thorough preoperative risk assessment is warranted, particularly in older patients. Indeed, delayed surgery was reported to be associated with a decreased mortality rate in some studies.
Type II Odontoid Fracture
Another commonly discussed topic in geriatric spinal trauma is decision-making in type II odontoid fracture. Just as in CCS, odontoid fracture in older patients is usually caused by hyperextension injury after a fall with background osteoporosis in the dens. As the space available for the cord is large in the upper cervical spine, most patients are neurologically intact, but its high cervical level of injury potentiates life-threating sequelae. The purpose of surgical stabilization is to obtain pain relief and to avoid late displacement of a fracture that leads to spinal cord injury, although associated ligamentous injury is rare, in contrast to high-energy odontoid fracture in younger patients. It is of note, however, that mortality in older patients with type II odontoid fracture is notably high and has been reported to be up to 30% to 40% in 2 years.
One of the most frequently cited studies in this field is the AOSpine North America multicenter prospective geriatric odontoid fracture study, which followed up 159 patients 65 years or older with type II odontoid fractures and showed that mortality was higher with nonsurgical management than with surgery. A weakness of this study is that it was not a randomized controlled trial, and possible selection bias excluding morbid patients could have resulted in favoring the surgical group. To date, the evidence to support the superiority of surgical intervention in geriatric populations in general is weak, and the surgical benefit in octogenarians is still questionable. Our recommendation is to offer it for those who are medically fit and for whom physical demand is reasonably high.
With regard to surgical options, posterior fusion at C1–C2 is a preferred method. Anterior odontoid screw osteosynthesis has been reported, but the bone union rate is not as high due to suboptimal screw purchase in osteoporotic bone. Nonsurgical options include cervical collar application and halo immobilization. It should be kept in mind that halo immobilization in older patients is associated with very high risk of respiratory complications (eg, dysphagia and aspiration pneumonia) and even mortality. As such, we recommend against the use of halo immobilization in older patients. Although bone union rates in nonsurgical options are not as high as in surgical options, fibrous nonunion without frank instability is generally an acceptable end point, and the outcomes are not different from a solid bone union.
Surgical decompression is recommended for moderate to severe DCM, even in geriatric populations. Cervical radiculopathy is generally self-limiting, but patients who do not respond to 6 months of conservative management or those with radiographic evidence of spinal cord compression may benefit from surgical intervention. CCS associated with preexisting spinal canal stenosis is common in older patients. Early decompression is generally recommended, but careful preoperative risk assessment and medical optimization are imperative in older patients. There is weak evidence to support lower mortality rates in surgically treated type II odontoid fracture, but recommendation for surgery should be made on case-by-case basis on the basis of patients' robustness and physical demand.
Burneikiene S, Nelson EL, Mason A, et al The duration of symptoms and clinical outcomes in patients undergoing anterior cervical discectomy and fusion for degenerative disc disease and radiculopathy. Spine J. 2015;15:427–432.
Carette S, Fehlings MG. Clinical practice. Cervical radiculopathy
. N Engl J Med. 2005;353:392–399.
Chapman J, Smith JS, Kopjar B, et al The AOSpine North America Geriatric Odontoid Fracture Mortality Study: a retrospective review of mortality outcomes for operative versus nonoperative treatment of 322 patients with long-term follow-up. Spine. 2013;38:1098–1104.
Fehlings MG, Tetreault L, Riew D, et al A clinical practice guideline for the management of patients with degenerative cervical myelopathy
: recommendations for patients with mild, moderate, and severe disease and nonmyelopathic patients with evidence of cord compression. Global Spine J. 2017;7(3 suppl):S70–S83.
Fehlings MG, Vaccaro A, Wilson JR, et al Early versus delayed decompression for traumatic cervical spinal cord injury: results of the Surgical Timing in Acute Spinal Cord Injury Study (STASCIS). PLoS One. 2012;7:e32037.
Fehlings MG, Wilson JR, Karadimas SK, et al Clinical evaluation of a neuroprotective drug in patients with cervical spondylotic myelopathy undergoing surgical treatment: design and rationale for the CSM-Protect trial. Spine. 2013;38:S68–S75.
Kadanka Z, Bednarik J, Novotny O, et al Cervical spondylotic myelopathy: conservative versus surgical treatment after 10 years. Eur Spine J. 2011;20:1533–1538.
Nakashima H, Tetreault LA, Nagoshi N, et al Does age affect surgical outcomes in patients with degenerative cervical myelopathy
? Results from the prospective multicenter AOSpine International study on 479 patients. J Neurol Neurosurg Psychiatry. 2016;87:734–740.
Schneider RC, Cherry G, Pantek H. The syndrome of acute central cervical spinal cord injury; with special reference to the mechanisms involved in hyperextension injuries of cervical spine. J Neurosurg. 1954;11:546–577.
Stevens EA, Marsh R, Wilson JA, et al A review of surgical intervention in the setting of traumatic central cord syndrome
. Spine J. 2010;10:874–880.
Tetreault L, Goldstein CL, Arnold P, et al Degenerative cervical myelopathy
: a spectrum of related disorders affecting the aging spine
. Neurosurgery. 2015;77(suppl 4):S51–S67.