Spinal Cord Injury (SCI)

Following initial spinal cord trauma, neuroscience has established an important secondary neurodegenerative process that occurs, which causes significant cord injury. Calcium entry into neurons and glial cells results in a cytokine and free radical cascade released by activated microglia and damaged mitochondrial membranes [1, 2]. Tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), matrix metalloprotease-9 (MMP-9), and nitric oxide (NO) promote the inflammatory-cascade, creating neuronal and oligodendrocyte damage. Demyelination of axons, neuronal inflammation and progressive disruption of nervous tissue follows with long-term consequences that impair SCI recovery [2, 3]. No proven pharmacological protocol providing protection from these secondary changes is currently available; however, research suggests acupuncture may inhibit this process. An experimental study of SCI in rats with sham/placebo control demonstrated acupuncture improved functional recovery after SCI compared to controls (P < 0.01). Acupuncture attenuated microglial activation (P < 0.01) and reduced expression of TNF-α (P < 0.01), IL-1β (P < 0.01), IL-6 (P < 0.01), MMP-9 (P < 0.05), NO synthase (P < 0.001), and cyclooxygenase-2 (P < 0.001). Reduced apoptotic cell death of both neurons and oligodendrocytes (P < 0.001) along with axonal loss and lesion size reduction on immune-histochemical staining (P < 0.05) demonstrated acupuncture provided neuroprotection [4].

Neuroplasticity defines the ability of nervous tissue to change structurally, resulting in functional changes. Trauma and neurologic disease alter plasticity-factors. Specific neurotrophins, such as brain-derived neurotrophic factor (BDNF) and neurotrophic factor-3 (NT-3) are endogenous plasticity promoters that may be key to recovery from SCI. These neurotrophins are downregulated in SCI [5] and SCI rodent-model studies suggest a positive correlation of BDNF and NT-3 levels with optimum functional neurologic recovery [6, 7] and reduction in neuropathic pain [8]. An SCI murine model study reported a positive correlation between electro-acupuncture’s neuro-protective effects and improved locomotor function recovery with the up-regulation of BDNF and NT-3 (P < 0.05) [9].

Intervertebral Disc Disease (IVDD)

In the traditional Chinese veterinary medicine (TCVM) paradigm, SCIs are due to Qi and Blood Stagnation, and acupuncture has long been used for various myelopathies. Multiple studies document the use of acupuncture for canine IVDD, as adjunct or alternative to standard management. While several studies present methodological flaws and researcher bias (groups not matched, evaluator not blinded), a trend toward faster, more complete recovery appears to be associated with electro-acupuncture (EA), and some authors have concluded EA may have a canine thoracolumbar (TL) IVDD treatment success rate up to 83–95% [10, 11]. In one study on 50 dogs with TL-IVDD, a significantly shorter time to recover ambulation was reported with conventional treatment + EA (10.10 ± 6.49 days) versus conventional treatment alone (20.83 ± 11.99 days; P = 0.0341) for non-ambulatory dogs with intact nociception (grades 3 and 4). The ability to walk without assistance for grades 3 or 4 and overall success rate were also significantly higher with EA (respectively P = 0.047 and 0.015) [12]. In a retrospective study (80 dogs) with paraplegia and intact nociception from TL-IVDD (grade 4), the combination of EA with prednisone was significantly (P = 0.01) more effective than prednisone alone to recover ambulation; allowed faster return to ambulatory status (P = 0.011), relieved back pain (P = 0.001) and decreased relapse rate (P = 0.031) [13]. Another study compared EA, hemilaminectomy and hemilaminectomy + EA in 40 dogs with more than 48 hours of severe neurologic deficits due to IVDD (only grades 4 and 5) confirmed by diagnostic imaging (MRI, CT, myelography). “Clinical success,” defined as a patient initially classified grade 4 or 5 then classified as grade 1 or 2 within 6 months of treatment, was significantly (P < 0.05) higher for dogs that received EA alone (15/19, 79%) or EA and surgery (8/11, 73%) than dogs with surgery alone (4/10, 40%) [14]. Refer to Table 21.1 for grading of neurological deficits.

Besides benefiting the spinal cord itself, EA has also shown effects on vertebrae and intervertebral discs likely to be beneficial in cases of IVDD. In a randomized controlled murine study, EA inhibited Wnt-β–catenin, which may delay the degenerative process of cervical intervertebral discs [15]. Acupuncture can also improve the ability of degenerated discs to repair by reducing the amount of type I collagen in the nucleus pulposus while promoting type II collagen, necessary for proper hydration of proteoglycans leading to compression resistance [16, 17]. In an IVDD rat model, EA also increased vertebral blood flow, micro-vessel density, and number of normal spinal cord neurons. [18]

TCVM can be used for cervical IVDD and, in the author’s opinion, may be one of the most rewarding conditions to treat with EA. A retrospective study (19 dogs, cervical myelopathy), used three different acupuncture protocols: dry needle acupuncture (DN) +/– EA, and Chinese herbal medicine (CHM).^1,2 All 19 dogs, which had previously failed conventional medical/surgical management (18 with IVDD, 1 with fibro-cartilaginous embolic myelopathy), reported both pain and neurological function improvement [19]. A case report also describes successful use of EA and herbals for IVDD at C3-C4 in a miniature Pinscher [20].

While the author still recommends advanced imaging and decompressive surgery when indicated for cases of presumptive IVDD, these results justify offering EA as an adjunct to the “gold standard,” whether the conventional management pursued is surgical or conservative. Suggested recommendations for TCVM use based on neurological deficit grade is included in Table 21.1.

Cervical Spondylomyelopathy (CSM)

A clinical trial of 40 dogs with presumptive or diagnosed CSM comparing standard treatment (medical and surgical) vs standard treatment + EA reported an overall EA efficacy of 85% versus 20% standard treatment only (noticeably lower than classically reported) [21]. A retrospective study of 19 animals (13 dogs, 6 horses) with presumptive or diagnosed CSM reported results obtained with the following TCVM treatments: DN, EA, aqua-acupuncture (1000 μcg/ml Vitamin B-12), CHM¹ for all patients, CHM² in grades 2 or higher, CHM³ in patients with cervical pain, and additional Chinese herbal medicines based on the Chinese pattern diagnosis. All animals showed improvement, except for one horse with poor tolerance of acupuncture, precluding completion of treatment [22].

As for IVDD, the author still recommends advanced imaging and surgery (if indicated) for presumptive cases of CSM, but also recommends integrating TCVM and neurological rehabilitation for ideal pain management and functional recovery.

Selection of Acupuncture Points Based on Neuroanatomical Function

For a more in-depth review of the anatomy and physiology relevant to acupuncture, the reader is referred to Section II, Chapters 4 and 6 of this textbook.

Recent studies have allowed identification of criteria associated with higher likelihood of effect when considering acupuncture points. Up to 70% of acupuncture points have been identified as motor entry points, which are locations where the motor branch of a nerve enters the muscle belly of an innervated muscle [23]. These points can be identified with neuromuscular electrical stimulation (NMES) as the point that will elicit maximal contraction of a muscle belly if stimulated. Recently, acupuncture points have also been identified as neurogenic inflammatory spots, which are areas of local tissue response caused by cutaneous neurogenic inflammation encountered in visceral disorders. They are located in the dermatome overlapping the visceral afferent innervation [24]. Features of neurogenic spots include: plasma extravasation, vasodilation in postcapillary venules of the skin, wheal-and-flare reaction and substance P from activated small diameter sensory afferents. Neurogenic spots also show hypersensitivity, high electrical conductance and small diameter nerve fiber-mediated sensation (C fibers, Aδ). Features which are classically associated with acupuncture points [25]. Overall approximately 70% of neurogenic spots were found to match acupoints. More importantly, in murine models of colitis and hypertension, acupuncture was effective when performed at acupoints that were also neurogenic spots, and ineffective at non-neurogenic spot acupoints [24].

Although it has been reported that acupuncture is more efficient when practiced according to patient TCVM Pattern diagnosis (See Section II, Chapter 5), based on these studies and personal observations, the author suggests including local points (e.g. Jing-jia-ji for cervical IVDD) and distal points (including specific acupoints identified as motor entry points and/or neurogenic spots) when using EA for neurological disorders (Table 21.2).

Electro-acupuncture Treatment Timing and Parameters

The author recommends acupuncture early after injury/surgery (ideally within 24–72 hours), in order to maximize benefits. Very low frequency EA (2–10Hz) is helpful in treating neuropathic pain and is, like low frequency EA (20–40Hz), associated with endorphins and enkephalins release. High frequency (80–120Hz) and very high frequency (200Hz) are associated, respectively, with dynorphin and serotonin release. Suggested protocol includes 10 minutes at low frequencies (20/40 Hz), followed by 5–10 minutes at higher (80/120 Hz) and very high frequencies (0/200 Hz), with added very low frequency (2–5Hz) for 5–15 minutes in case of neuropathic pain, based on severity and patient’s tolerance. The author suggests starting each session with “permission points” (e.g. GV-20 and bilateral An-Shen) to help patient compliance, and recommends EA 1–2 times/week for the first 3 weeks prior to considering progressive reduction of frequency.

Another benefit is that, acupuncture as a “passive” modality, is acceptable therapy in acute inflammation when the patient may not be a candidate for other interventions (e.g., pain preventing active treadmill work or unstable vertebral fractures) or early post-operative period (Figures 21.1 and 21.2).

Canine Models of Spinal Cord Injury

Studies in canine models of SCI support the positive association between BDNF and functional recovery [41, 42], with higher levels of BDNF being associated with improved recovery, which can be stimulated with sustained exercise in dogs [43]. However, MMP-9, a pro-inflammatory metalloproteinase, may dampen the benefits of treadmill training in promoting BDNF and NT-3 [35], highlighting the possible synergistic effect of using treatment modalities diminishing neuro-inflammation (e.g. acupuncture, laser) concomitantly to locomotor training. Hence, locomotor training (e.g. land treadmill) appears as a cornerstone for a neuro-rehabilitation program in dogs. In clinical practice, treadmill training is routinely used to initiate rhythmic locomotor movements and is relatively easy to implement (Figure 21.3). In the authors’ experience, patients with a remaining degree of motor function (whether ambulatory or not) benefit most from treadmill training. Animals with severe deficits and paralysis may show limited benefits, or even detrimental in stimulating negative neuroplasticity and/or compensation.

Intervertebral Disc Disease (IVDD)

Several studies report the use of physical rehabilitation in dogs recovering from TL-IVDD surgery, with conflicting findings regarding results, but an overall trend toward improved recovery. Many studies are retrospective, address patients that were non-ambulatory at presentation, involve some rehabilitation even in the control group and all involve multimodal therapy in the protocols including physical exercise (e.g. land treadmill once patients can stand, NMES, balance board, laser therapy) [44–50].

A randomized, blinded, prospective clinical trial on 30 non-ambulatory paraparetic or paraplegic dogs (with pain perception) after surgery for TL-IVDD found that early initiation of intensive postoperative rehabilitation was safe and well-tolerated. No significant improvement in outcome, however, was found when comparing early intensive post-operative rehabilitation [supported standing, NMES, weight shifting/balance board exercises, underwater treadmill] to less intensive post-operative treatment (ice/hot packs, passive ROM, sling walks) [44]. The lack of significant benefits of intense neurologic rehabilitation program(s) in outcome is limited to this study, as all other published studies, albeit retrospective concluded some benefits. A retrospective study on 248 non-ambulatory dogs reported multimodal post-operative rehabilitation did not accelerate recovery, but improved functional outcome with higher chance of complete recovery and lower chance of complications [45]. Another similar retrospective study (186 dogs) reported faster and significantly higher successful outcome with multimodal rehabilitation than without, for all neurological grades (86%, 83/96 vs 52%, 47/90; P < 0.01) [46].

A larger retrospective controlled clinical study (367 paraplegic dogs) also reported significant improvement in recovery of ambulation with intensive neurorehabilitation (P < 0.001) [47]. Finally, another retrospective study of 113 dogs treated with comprehensive rehabilitation post-operatively reported that more time in formal rehabilitation (P < 0.001) and more underwater treadmill sessions (P < 0.001) increased the chances of improvement [50]. This trend is also reported in cervical IVDD, with a retrospective study (58 dogs) reporting significantly higher success with multimodal rehabilitation post-operatively (27/34 vs 15/24; P < 0.05) [51].

Degenerative Myelopathy

A retrospective study reported on the effects of varying intensities of physical rehabilitative therapy on survival and length of ambulatory status in 50 dogs with presumptive degenerative myelopathy (DM) [52]. Survival time was positively associated with the degree of physical rehabilitation therapy. Dogs that received intensive physical rehabilitation (n = 59) had longer survival time (mean 255 days) than dogs with moderate (n = 56, mean 130 days) or no (n = 57, mean 55 days) rehabilitation (P = 0.05). The authors reported that, compared to the group with intensive physiotherapy, the risk of death was 5.8 times higher (P = 0.046) for dogs with moderate physical rehabilitation and 112 times higher (P = 0.001) for dogs without physical rehabilitation [52]. Another retrospective study on 20 dogs with presumptive degenerative myelopathy (DM) receiving a combination of rehabilitation therapy and either one of two different PBMT therapy protocols showed no difference in survival time compared to historical controls for one of the groups, but there was significantly longer time to reach non-ambulatory paraparesis along with longer survival time for the group receiving intense laser therapy treatment (p < 0.05) [53]. Despite study limitations (e.g. few dogs with confirmed DM), this and physical rehabilitation are the only clinical therapies documented that suggest slower disease progression.