J Manipulative Physiol Ther 2001 (Nov); 24 (9): 589–595 ~ FULL TEXT
Bradley S. Polkinghorn, and Christopher J. Colloca
Private practice of chiropractic,
Santa Monica, Calif., USA
OBJECTIVE: To describe a case of postsurgical neck pain, after multiple spinal surgeries, that was successfully treated by chiropractic intervention with instrumental adjustment of the cervical spine.
CLINICAL FEATURES: A 35-year-old woman had chronic neck pain for over 5 years after two separate surgeries of the cervical spine: a diskectomy at C3/4 and a fusion at C5/6. Surgeries were performed 6 months apart in an attempt to resolve persistent neck pain and spasm of the cervical musculature. Neither surgery was effective in relieving the patient's pain. Five years after the second surgery, a third surgery was recommended by the patient's physicians to alleviate the chronic pain. The patient sought chiropractic evaluation of her condition to avoid further surgical intervention.
INTERVENTION AND OUTCOME: The patient was treated with conservative instrumental chiropractic manipulation, consisting of mechanical force, manually assisted short-lever spinal adjustments rendered with an Activator Adjusting Instrument (AAI) II. She comfortably tolerated the treatment and responded favorably to this therapy. All chronic symptoms had resolved within 30 days of instituting the chiropractic instrumental adjustments with an AAI. More interestingly, longitudinal examination over the next 2 years showed that the patient experienced no residual effects or further recurrences of her previous chronic problem after her initial course of chiropractic care.
CONCLUSIONS: Chiropractic treatment of postsurgical neck syndrome may be effectively treated, in certain cases, by mechanical force, manually assisted adjusting procedures with an AAI. The use of instrumental adjustment methodology may provide chiropractic physicians with an effective alternative to manual manipulation in those cases in which the patient's surgical history or presenting symptoms make forceful manipulation of the spine, particularly performed at end range, inappropriate. This approach may be contemplated by physicians faced with managing this type of condition. Further study should be made in this regard, in an academic research setting, to determine the safest and most effective approaches to managing postsurgical patients in a chiropractic setting.
From the Full-Text Article:
Resolution of chronic postsurgical neck pain and dysfunction by means of the conservative chiropractic care observed in this case is an encouraging outcome. Most obvious is the positive outcome of symptomatic and functional resolution of the patient as well as her return to normal activities of daily living. The avoidance of subsequent surgical intervention is also of great significance. Noteworthy is the understanding that the success of arthrodesis and clinical outcome is more difficult when performed adjacent to a prior fusion.  Based on her experience with previous surgical intervention, it is understandable that the patient sought alternative conservative measures rather than a third cervical spinal surgery.
Kinematic evaluations of the cervical spine in patients with postsurgical fusion indicate that an alteration in the biomechanical behavior of adjacent functional spinal units is likely responsible for a degenerative fate.  Instantaneous centers of rotation have been found to shift anteriorly with flexion/extension movements of the cervical spine in patients undergoing fusion for cervical disk degeneration as compared with controls.  Altered function in adjacent cervical spinal segments have also been reported by Matsunaga et al.  They discovered abnormally high strains in cervical intervertebral disks postoperatively and noted accompanying herniation in some disks after anterior cervical decompression and fusion for herniation. Shifted centers of rotation have been found not only to be indicative of dysfunction but to be a cause of neck pain as well. 
Symptomatic adjacent-segment disease may affect more than one-fourth of all patients within 10 years after an anterior cervical arthrodesis.  Retrospective evaluations of patients who have undergone cervical spinal fusion indicate an increased rate of degenerative disease at the levels immediately adjacent to the fusion. [46-48] Other studies have demonstrated a 9% incidence of symptoms attributable to another level that may require a subsequent surgery.  Such information suggests avoidance of repetitive cervical spinal surgery whenever possible and provides insights into the possible etiology of the patient's presenting symptoms.
The progressively worsening neck and shoulder pain accompanied by burning and severe neck spasm are most likely attributable to nociceptive afferent stimulation in the discoligamentous soft tissues of the cervical spine, including the zygapophyseal joints. Although the most implicated source of post-traumatic chronic cervical neck pain is the zygapophyseal joints, [50-52] the cervical intervertebral disks and cervical musculature have also been implicated as pain generators as well. [53-57] Figure 3 demonstrates the referred pain patterns from the lower cervical zygapophyseal joints to the upper thoracic spine, consistent with the patient's presentation.
Cervical discogenic or muscular pain would be likely to cause similar patterns because of the nature of the neurologic pathways responsible for such a referred distribution. Abnormal mechanical loading and altered kinematics of the postsurgical spine through mechanical and inflammatory means are a reasonable explanation for the stimulation of nociceptive afferent units that ultimately lead to pain recognition,  as witnessed in this case.
On physical examination, including palpation to the cervical spine, mechanical pressure reproduced the presenting symptoms consistent with hyperalgesia (abnormally intense pain produced by normally painful stimuli) from underlying nociceptive sensitization. [59-60] Hyperalgesia has been found to amplify protective muscular reflexes and promotes immobilization of the injury.  This may also help to explain the patient's inability to move her neck without severe pain “bringing her to tears.” Of further interest was the worsening of the patient's symptoms with weather changes. Changes in weather sensitivity have been observed in patients with chronic pain.  One of the many possible explanations is that such nociceptive excitability may be stimulated by changes in barometric pressure or temperature, reflecting underlying peripheral nociceptive or central sensitization.
In this case, the chiropractic intervention of choice was MFMA short-lever spinal adjustments with the AAI. Activator Methods Chiropractic Technique  includes a protocol known as isolation testing in which the patient is asked to perform specific active range of motion tests while the observer monitors any changes in leg alignment reactivity. Changes in leg alignment reactivity are supposedly indicative of underlying alterations of muscular reflexes associated with neurologic facilitation/subluxation in this methodology. Although preliminary studies have begun to investigate this phenomenon,  it has not been subject to scientific scrutiny and remains unvalidated.
MFMA spinal adjustments are delivered to the patients' cervical spine while the patient is in the prone neutral position. The AAI provides a controlled means of delivering high-velocity thrusts to the patient without having to rotate the spine in the treatment delivery. As observed in this case, cervical range of motion reproduced severe pain during the physical examination. Therefore, the choice of treatment by MFMA adjusting provided a useful alternative to HVLA manipulation in this case and may also prove useful in similar cases in the future.
Rapid distraction of the functional spinal unit as applied in spinal manipulation is hypothesized to release entrapped synovial folds, relax hypertonic muscles, disrupt articular or periarticular adhesions, and unbuckle functional spinal units that have undergone disproportionate displacements.  Although evidence has yet to substantiate these concepts, concomitant neuromuscular reflex responses associated with spinal manipulation are promising factors associated with both traditionally applied manual and MFMA interventions [25, 63-66] because afferent stimulation has been attributed to nociceptive inhibition.  Such responses are thought to originate from stimulation of mechanosensitive afferents in the discoligamentous and muscular soft tissues of the spine on distraction  or other mechanical stimulation. 
Reflex effects associated with spinal manipulation have not been found to be related to the magnitude of force application or the presence of an audible joint cavitation but rather the rate at which the force is applied.  In this regard, MFMA spinal adjustments may serve as effective as the more forceful, manually delivered HVLA adjustments of the cervical spine.  Indeed, several recent pilot studies comparing the clinical outcomes of both MFMA and HVLA chiropractic adjusting techniques have found the two to be equally effective in relief of pain. [20, 23, 71] Research has begun to investigate the functional effects of spinal manipulation in terms of influencing the musculoskeletal system and functional patient outcome. [66, 72] Resolution of this patient's symptoms and the return of functional status after chiropractic intervention are most encouraging in this regard. Further research is required to investigate the nociceptive inhibitory effects of spinal manipulation or chiropractic adjustment and its role in improving patient clinical status.
Chiropractic physicians are often called on to treat postsurgical neck and back symptoms. Appropriate and carefully performed manual manipulation has been reported to help in many of these cases.  However, depending on the nature and extent of the previous surgery, forceful HVLA manual manipulation performed at end range may present an unwanted risk of aggravation or be completely inappropriate from the outset because of the severity of the patient's presenting pain and underlying structural weakness.  Chiropractic treatment of postsurgical neck syndrome may be effectively implemented, in certain cases, by using MFMA adjusting procedures with an AAI. The use of instrumental adjustment methodology may provide chiropractic physicians with an effective alternative to traditional HVLA manual manipulation in those cases in which the patient's surgical history or presenting symptoms make forceful manipulation of the spine, particularly performed at end range, inappropriate. Conservative MFMA methodology may therefore be considered by physicians faced with managing these types of conditions.
As with any form of chiropractic management of the patient with FBSS, MFMA adjusting methodologies are directed toward the treatment of the concomitant vertebral subluxations that may adversely affect spinal stability. Chiropractic adjustments are therefore not a generic treatment for all forms of FBSS, and each patient must be screened selectively to determine those who may best respond to chiropractic intervention. Further study should be made in this regard, in an academic or clinical research setting, to determine the safest and most effective approaches to managing postsurgical patients in a chiropractic setting.