Postoperative rehabilitation after spinal surgery is widely accepted in human medicine as having a positive effect on patient outcome. As an example, a conclusive study carried out by Green et al (2016) on the effects of rehabilitation with human patients after a total lumbar disc replacement found physiotherapy to improve functional disability, pain and quality of life. Consideration as to whether similar post-operative rehabilitation techniques would have a positive impact on recovery times for canine patients undergoing a hemilaminectomy is therefore an important topic. As this literature review will demonstrate, the applicability of this notion to veterinary medicine remains inconclusive and contested.
There are many research papers and discussions surrounding intervertebral disc disease and its surgical management via a hemilaminectomy. Despite this there is a relative paucity of academic work regarding recovery rates and the recovery process itself. However, the rapid growth of the rehabilitation profession over the past couple of years has meant that more scientific evidence is becoming available. Patients recovering from hemilaminectomy are often severely compromised (Moore et al, 2016). The inability to move their limbs, urinate or defaecate, and move from lateral to sternal recumbency highlights the profound importance of nursing and supportive care required. Key aspects of the rehabilitation process in-clude pain management, bladder evaluation, skin care, physiotherapy, correct nutritional intake and prevention of sores and decubitus ulcers.
Rehabilitation therapies
Photobiomodulation and low-level laser therapy
The use of photobiomodulation or low-level laser therapy as part of the rehabilitation protocol for dogs post hemilaminectomy has been discussed by Hodgson et al (2017). Its use is supported by Sims et al (2015) and Draper et al (2012) as it is thought to stimulate nerve cells and supporting structures, enhancing the recovery of peripheral nerves. In human medicine it is clinically proven that low-level lasers improve wound healing in the compromised patient (Dawood and Salman, 2013). A study by Bennaim et al (2017) also discussed the use of low-level laser therapy as part of the rehabilitation protocol, unfortunately this study was inconclusive because of the study size. There are standard regulations surrounding the use of lasers meaning the purchase and set up fees can be fairly large. This, therefore, could make it hard to implement in practice but should not be discounted as part of the rehabilitation process because of the evidence of positive effects both in human (Dawood and Salman, 2013), and veterinary medicine (Draper et al, 2012).
Neuromuscular electrical stimulation
Neuromuscular electrical stimulation (NMES) postoperatively has been widely discussed by Hady and Schwarz (2015) and Zidan et al (2018) who both used NMES as part of their postoperative rehabilitation. NMES is considered to show the best improvement when it is used as part of a multimodal approach (Frank and Roynard, 2018). It is proven to be an integral part of the rehabilitation protocol because of its ability to prevent muscle atrophy and enhance joint movement (Millis and Ciuperca, 2015), both of which are incredibly important during the recovery from intervertebral disc herniation (IVDH). The evidence from Zidan et al (2018), Hady and Schwarz (2015), Frank and Roynard (2018) and Millis and Ciuperca (2015) all suggest that this should definitely be considered as part of a rehabilitation protocol in practice. With correct training NMES is easy to apply and use safely.
Passive range of motion
Sims et al (2015), Bennaim et al (2017), Zidan et al (2018), Hady and Schwarz (2015) all support the use of passive range of motion (PROM). Some benefits include improved circulation, stimulation of sensory and proprioceptive pathways and prevention of joint stiffness. The use of massage is said to help with circulation and lymphatic drainage, which allows better tissue oxygenation and resolution of oedema. Massage normally provides relaxation for the patient and can provide relief for patients experiencing muscle tremors and spasms. It is a technique widely used in human medicine because of its relaxation and pain alleviating properties (Sims et al, 2015). PROM, massage and strength exercises are easy to implement and have positive supporting evidence to back up their use in practice (Draper et al 2012; Hady and Schwarz 2015; Zidan et al 2018).
Hydrotherapy
Hydrotherapy is another physical therapy that is widely discussed across the different papers reviewed (Hady and Schwarz, 2015; Hodgson et al 2015; Sims et al, 2015; Bennaim et al, 2017; Zidan et al, 2018). It is incorporated into most of the treatment protocols reviewed once the incision site is healed and has been linked to patient improvements. Aquatic therapy can either be swimming in a controlled environment (Figure 1) or on an underwater treadmill. The water resistance maximises the exertion on the muscles which allows strengthening with minimal activity. The warm temperature of the water between 26–30°C (Tomlinson, 2012) helps to promote blood circulation and lymphatic drainage. In human medicine underwater exercise has been shown to have less effect on the cardiovascular and respiratory systems (Schaal et al, 2012) meaning that it could benefit obese patients; this could be a consideration for canine patients with higher body condition scores. However, a study by Gordon-Evans et al (2018) found no link between high body condition scores and recovery time in patients recovering from a hemilaminectomy. Hydrotherapy is costly to set up and requires trained persons to run the sessions, so is not practical in most practice settings. Referral to a hydrotherapy centre would be the easiest option in this instance.
Acupuncture
A rehabilitation therapy that has not been discussed in any of the three papers evaluated is acupuncture. Roynard et al (2018) defines acupuncture as ‘the stimulation of specific points on the body surface by the insertion of a needle, resulting in therapeutic and homeostatic effect’. Acupuncture is known to stimulate the production of beta-endorphins which have a positive effect on long-term analgesia (Skarda et al, 2002). Acupuncture also improves motor functions, which has resulted in its effective employment in the treatment of neurological dis-orders including IVDH in veterinary patients (Roynard et al, 2018) (Figure 2). It should thus be considered when implementing a rehabilitation protocol. Further evidence by Joaquim et al (2010) supports the notion that acupuncture significantly improves patients' outlook. The requirement for a trained and qualified person is possibly the fundamental reason it is not widely used in practice.
Research into the benefits of rehabilitation
Zidan et al (2018) conducted a randomised, blinded, prospective clinical trial, evaluating the difference that basic and intensive rehabilitation had on the time to ambulation. The population consisted of canine patients that were non-ambulatory paraparetic or paraplegic with deep pain perception postoperatively for thoracolumbar IVDH. The initial assessment included 50 patients but only 32 met the inclusion criteria and only 30 dogs completed the trial as a result of two contracting infections. The dogs were put into either the basic or intensive 14-day rehabilitation groups using a randomised 1:1 ratio, with equal numbers of non-ambulatory paraparetic versus paraplegic dogs randomly placed into each treatment group. Both groups started their rehabilitation the day after surgery and both received the basic protocol of cryotherapy for the first 24 hours, then thermotherapy, PROM exercises and sling/supportive walking. The dogs in the intensive group had additional therapies which included supported standing, weight shifting, NMES and underwater treadmill exercise. Both groups went home with the same PROM and sling/supportive walking instructions at around day 15. They were re-evaluated at day 28, to check their progress, and at the end of the trial at day 42 to determine if their rehabilitation had been maintained from day 14.
The primary measures assessed in this trial were changes in walking without support — measured by the open field gait score (OFS) — or the coordination regulatory index (RI) if walking without support was not possible. Pain assessment was also conducted using the Glasgow Composite Pain Scale (GCPS); weight was also measured. Differences in OFS and GCPS between the two trial groups were not statistically significant. Therefore, the only compelling conclusion offered by this study was that dogs would tolerate intensive rehabilitation post-hemilaminectomy.
Unlike the subsequent papers to be examined in this article, the study conducted by Zidan et al (2018) had the strength of being a randomised, blinded, prospective study. This would have eliminated many of the unknown variables which can negatively impact retrospective studies whose control and study groups are fixed in advance. Perhaps the greatest weakness of the study though was its extremely small size — only 30 patients in total across the two groups. Had the trial benefitted from a much larger sample size, it is possible that greater statistical variations between the basic and intensive therapy groups could have been observed. The size of this trial was arguably too small to enable random variations and outliers in the results to be averaged out so as to produce a more stark contrast in the results.
A retrospective cohort study by Hodgson et al (2017) on the effects of in-house rehabilitation in relation to patient recovery from IVDH produced more compelling results than those obtained by Zidan et al (2018). The study's population was canine patients under 20 kg bodyweight that had received surgery for a single site thoracolumbar Hansen Type 1 IVDH. A review of 885 medical records from one practice was carried out with 248 meeting the in-clusion criteria, 87 of those were in the rehabilitation group and 161 in the control group. In each group the pre-operative and postoperative modified Frankel Scores (MFS) were recorded. This scale classifies spinal injuries by grading neurological deficit on a scale of zero to five. In both groups time to conscious proprioception, ambulation and final MFS were compared. Any complications within the groups were also recorded and compared as outcome measures. These neurological examinations were carried out by a single boarded veterinary surgeon, pre-operatively then daily until discharge, at day 10–14 and at 4–6 weeks post-operatively. If full recovery was achieved before 6 weeks no further examinations were performed. The control group received cryotherapy, PROM exercises and laser therapy as part of the standard protocol. These were included in the rehabilitation group with additional treatments including sit/stand exercises, underwater treadmill exercise, weight shifting, land treadmill exercise and cavaletti drills.
The results were interesting. The median time to ambulation was longer for the rehabilitation group (28 days) than the control group (14 days). Additionally, conscious proprioception was on average regained faster in the control group (42 days) than the rehabilitation group (49 days). However significantly 33% of dogs in the rehabilitation group reached a final MFS of 5 (full neurological function) compared with only 9% in the control group. This suggests that rehabilitation was likely beneficial after all. The longer times for return to ambulation and conscious proprioception were highlighted by Hodgson et al (2017) as counterintuitive. They suggest that selection bias could have been a factor as the retrospective nature of the study afforded no control over the allocation of patients into the two groups. The more serious cases could have tended towards recommendations for rehabilitation, thus introducing the bias.
Although this study was careful to incorporate strict inclusion criteria to ensure the validity of its findings, it was hampered by a number of inherent limitations. Of particular note, with just 248 cases spread across both control and study groups, was the scant opportunity to average out random errors or to identify outliers which could have resulted in misleading conclusions. Additionally, as a retrospective study there was no mechanism to randomly assign patients to either control or study groups, and thus there could have been unknown factors which influenced the outcomes of each of those groups.
Hady and Schwarz (2015) conducted a retrospective study investigating the effects of physical rehabilitation on canine patients recovering from thoracolumbar IVDH Hansen Type 1. A review of 133 cases was conducted, 20 were excluded because they did not want to participate in a clinical trial, leaving 113 dogs in the study. Each dog was examined and assigned an MFS at the time of surgery and when they started and finished rehabilitation. This examination was carried out by the same trained person recording any changes in thigh circumference, pain, proprioception and ambulation. All patients received a rehabilitation protocol of NMES, PROM exercises, massage, sensory stimulation and sling-assisted walking. As they recovered, they advanced onto the use of the underwater treadmill, wobble boards and cavaletti poles.
The study was thought to be inconclusive because of the inconsistency of the trial and the authors recommended further controlled studies to look into the individual rehabilitation modalities and which combinations had the greatest effect on shortening and improving recovery of TL-IVDH.
Although a useful and enlightening study, the validity of the conclusions reached by Hady and Schwarz (2015) must be balanced against the limitations of their study. They were unable to include an effective control group, had issues consistently applying an objective scoring system and were confined to a small study size.
Conclusion
The evidence supports a multimodal approach to rehabilitation which seems to be the most effective way of improving patient outcome. Although rehabilitation has not been shown to improve recovery times, research has implied that it helps patients to recover with fewer deficits in strength and coordination. It is interesting that physiotherapy is widely known to improve human patient outcomes post-spinal surgery, yet the evidence presented in the papers reviewed in this article is far less compelling. Given the strong links between human and veterinary medical care, it seems likely that studies with larger sample sizes and with increased compensation for variations in initial neurological impairment states would reduce such ambiguity. Larger prospective studies, which are randomised and blinded, would likely produce statistically and clinically significant results. These would likely highlight further benefits from post-hemilaminectomy canine rehabilitation roughly commensurate with their human counterparts. The requirement for future trials in this area should include investigating the individual physical therapies and the effects they have on recovery times postoperatively.
All physiotherapy techniques and protocols are best overseen by a qualified physiotherapist alongside the principle veterinary surgeon. Of note, the Association of Chartered Physiotherapists in Animal Therapy (APCAT) are one of the governing bodies that work closely with the RCVS. All of their members are chartered physiotherapists (MCSPs) who have undertaken further qualifications in animal rehabilitation and physiotherapy to ensure correct and effective treatment protocols. Further information on ACPAT can be found at https://www.acpat.org.
KEY POINTS
- There are limited studies on the impact that rehabilitation post-hemilaminectomy has on patient recovery times.
- A multimodal approach to rehabilitation has been used in most of the studies reviewed.
- Although a multimodal approach may not necessarily improve recovery times, current research indicates that it helps patients to recover with fewer deficits in strength and coordination.
- The benefits of postoperative rehabilitation for animal hemilaminectomy patients remain contested and inconclusive.