Horse Physiotherapy

Case Study

The successful use of veterinary physiotherapy in the management and rehabilitation of surgically corrected over-riding dorsal spinous processes.

Summary

A 17 year old thoroughbred mare presented for resection of over-riding dorsal spinous processes (ODSP’s) diagnosed on radiographic examination. Surgery involved the complete removal of the spinous processes of three vertebrae.

Referral to veterinary physiotherapy was made at two weeks post surgery. After a full physiotherapy assessment, a problem list was drawn up. The list was then used to influence the use of a 16 week rehabilitation program that included the use of electrotherapy, manual soft tissue therapy and progressive exercise.

This program is presented as an example of how progressive exercise rehabilitation can be applied in the management of post-operative surgically corrected over-riding dorsal spinous processes.

Keywords: Veterinary Physiotherapy, over-riding dorsal spinous processes (ORDSP’s), kissing spines, exercise rehabilitation, electro-muscle stimulation.

Introduction

Over riding dorsal spinous processes, commonly referred to as ‘kissing spines’, is noted to be the most common anatomical abnormality reported in the horse with back pain (Henson and Kidd, 2009; Jeffcott, 1980; Walmsley et al. 2002). Impinging or over riding dorsal spinous processes (ORDSP’s), describes the loss of space between adjacent dorsal spinous processes (DSPs) within the equine spine.

There is currently much debate over the actual causes of pain, as the presence of ORDSP’s have being found in many athletic horses with little or no clinical signs of back pain on post mortem examination (Townsend et al., 1986; Haussler et al., 1999). Risk factors include sustained dorsal flexion, breed and lack of core stability (Henson, 2009)

In the thoroughbred, the incidence of ORDSP’s is common (Zimmerman et al., 2012). Reasons for this may be attributable in part or combined with; premature training loads associated with racing, the shape of the summits of the dorsal processes (Henson, 2009), or the use of half tree saddles used commonly in the racing industry (Head, 2009).

Current management

In many diagnosed cases, surgical removal of the impinging DSPs is performed, leading to the need for appropriate post operative management strategies. In a study evaluating the management of the condition, surgical intervention in 215 horses was presented. Ridden work commenced at 3-6 months post surgery in all successful cases (Walmsley et al., 2002).  At present there is limited evidence and lack of guidance in the management of post operative kissing spine surgery.

As physiotherapists in human practice, many routine operations are supplemented by post operative protocols that guide appropriate rehabilitation based on the presentation of the patient. Currently, these are generally lacking in the veterinary physiotherapy profession.

Case History

We present a case history of one thoroughbred mare referred to physiotherapy following surgical removal of identified ORDSP’s. On presentation at the referral hospital, radiographic examination revealed one impinging DSP between thoracic vertebrae (T) 14 and T15 with T13 and T14 and T15 and T16 being closely opposing and over-riding. Based on radiographic examination it was proposed that the dorsal processes of T13 and T15 were to be removed under standing sedation and local anaesthesia. During surgery it became apparent that the T14 dorsal spinous process was not going to withstand being the remaining process in this region of the thoracic spine and so this was removed in its entirety creating a space between T12 and T16.

Post operative advice regarding the rehabilitation and aftercare consisted of initial box rest and in-hand walking for 15 minutes daily for the initial 4 weeks. The owner was requested to turn the mare out in a small paddock for a further 4 weeks after this period (40 by 40 square feet). At 8 weeks, complete turn out in her normal paddock could be introduced, at which point lunging exercise could to begin, assuming there was adequate healing of the incision sight. Recommendations were made to use a pessoa when lunging to encourage spinal stability. This was described  to aid in rehabilitation of the musculature of the thoracoloumbar spinal region. (Walker et al 2013)

Ridden exercise was advised to commence 12 weeks following surgery once a repeat assessment by the referring vet had taken place. In addition, the owner was told to perform spinal stretches in to lateral flexion to the left and right for two weeks following suture removal to encourage flexibility in the back. There was no further detail or advice offered regarding the number of sets and repetitions. Dynamic mobilisations of the cervical spine increase cross sectional area of spinal stabilisers when using a specified number of sets and repetitions over a period of three months (Stubbs et al, 2011).

It was the intention of the physiotherapist to continue with the outined plan set out by the vet. However, by employing evidence based sets, repetitions, time frames, progressive exercises and goals the phsyiotherapist aimed to enhance this plan and educate the owner in the anticipation of greater compliance.

Assessment Findings

Physiotherapy assessment took place 5 weeks post surgery and a full subjective history noted the previous details.

Subjective assessment consisted static and dynamic visual observation of posture, muscle (a)symetry and gait, palpation, joint mobilisation, reflex assessment and specific pain provocation testing.

Postural Observation

Postural observation showed the mare had adopted a sway backed posture and a lordotic lumbar spine. There was moderate atrophy of the longissimus over the surgical site bilaterally to T12-16. Observation of the gait at walk showed hind limb stride length was reduced bilaterally, the mare did not show any ability to over track.

Palpation

Palpation of soft tissue using the physiotherapists hand was performed both parallel and perpendicular to the orientation of the cervical, epaxial and superficial gluteal muscle fibres. Muscle spasm of the longissimus and bilateral superficial gluteals was identfied. Palpation of the thorocolumbar fascia identified localised myofascial triggure point bilaterally at the level of the thorocolumbar junction. Guarded muscle spasm of right and left omotrasversarus and splenseus muscles were identifed via palpation of the cervical spine.

Joint Mobilisation

Mobilisation of the cervical vertebrae was performed using maintland occilations to the vertebral bodies in a trasvers direction. Stiffness between C3/4 and C5/6 facet joints. Costovertebral joints were assessed using Maitland oscillations performed at grade I-II in a dorsal direction identified resistance at ribs 13-16 bilaterally.

Pain Provication

The behaviour and reactions of the mare towards assessment procedures were consistantly monitored for pain reaction, adhearance to certain pressure. Pressure over the tuber secrale and tubera coxae was performed to test for pain reaction (Hesse et al., 2010)

Problem List

Epaxial muscle atrophy between T12-T16.

Bilateral muscel spasm of omotransversaris, longissimus, thorocolumbar fascia and superficial gluteals.

Facet joint stiffness C3/4 and C5/6Costovertebral stiffness at ribs 13-16

Lordotic/ sway back posture

A list of goals were set to influence the treatment plan:

Restore muscle mass of logissimus between T12-T16.

Restore resting muscle length of omotransversarius, longissimus, thorocolumbar facia and superficial gluteals

Increase cervical facet joint mobility at C3/4 and C5/6

Increase costovertebral joint mobility at ribs 13-16

Strengthen abdominal musculature/ facilitate abdominal control

Discussion

Neuro-muscular Electrical stimulation (NMES)

In human studies, the use of NMES results in increasing circulation and subsequent oxygen supply which can enhance the rate of healing of soft tissues to which it is applied (McDonough et al., 2002). Unfortunately, there is little evidence to evaluate its use in equine practice. However, the application for this case study aimed to increase muscle development of the longissimus muscle at the surgical site and aid in facilitating neuromuscular control. The application was well tolerated by the mare.

The frequency of application was twice weekly. This was due to the availability of both the owner and the physiotherapist.

Baited Cervical Stretches

Dynamic cervical stretches of the neck have been proven to increase cross sectional area of spinal stabilising muscles when performed over 3 months. (Stubbs et al., 2011). The physiotherapist advised to the owner on the number of sets, repetitions and direction of movement in accordance with current evidence (Stubbs et al., 2011)

Manual Mobilisation

Excessive or repetitive forces can compromise tissue healing in the proliferation phase (Paulekas et al., 2009). Joint mobilisation using Maitland oscillations at progressive grades were used at the cervical spine from the beginning of the rehabilitation program. Costovertebral joints mobilisations took place at week 7 at grade I, increasing the grade of mobilisation over the following weeks.

A combination of acupressure and reflex inhibition therapy was applied to the longissimus dorsi (Wakeling et al., 2006), superficial gluteals and omotransversarius at the start of rehabilitation.

Long reining

Studies in to the effect of lunging on longissimus activity have shown that movement on a circle produces 2-3 times more activity of the muscle on the inside of the turn than on the outside (Cottrial et al., 2008). The physiotherapist felt that asymmetrical muscle activity during the early phases of the rehabilitation program may encourage asymmetrical development of spinal stabilisers. During the proliferation of tissue healing, asymmetrical forces placed on healing tissue may risk further injury if repair is not adequate (Paulekas et al., 2009).

Long reining was proposed as a method of facilitating postural control without causing continuous side flexion of the back and thus encouraging asymmetrical development. There is very limited evidence on the effect of long reining on the spinal stabilisers. However, by using this modality the owner was able to facilitate exercises that challenged proprioception, abdominal control and spinal stabilisation through the use of incline and decline walking (Robert et al., 2001), ground pole placement and alternating surfaces (Paulekas et al., 2009). Initial training was performed in the enclosed environment of the arena (Figure 1), followed by progressive incline and decline work over hills, (Figure 2).

‘Passoa’ Lunging

Studies assessing the effect of the ‘Passoa’ training aid have found that this provides a safe encouragement of core activation and postural correction without increasing loads to the fore and hind limbs (Walker et al 2013). Due to the age if the mare in this case study, the author felt that it was important to control loading through the limbs and therefore support the use of the Passoa training aid when lunging.

Subjective Measures

Subjective measures included repeated palpation and observation of muscle symmetry, spinal posture, stride length and joint mobility. This was carried out twice weekly during physiotherapy visits.

Objective Measures

This study was limited with objective measurement. The physiotherapist could have utilised equipment to measure stride length, spinal position and muscle resistance but this was unavailable at the time of treatment.

Unfortunately, due to limited access to objective assessment measures the physiotherapist cannot prove nor disprove alleviation of problems identified at the start of treatment. However, following completion of the program, the mare did return to her preoperative level of work. This consisted of three 40 minute hacks per week that included incline, decline and pole work. Schooling now takes place three times a week in the arena lasting approximately 30 minutes. The mare has successfully competed in unaffiliated dressage.

After Care

The owner continues to perform cervical baited stretches once a day for a total of five repetitions. This consists of left and right lateral flexion towards the girth, left and right flexion to the level of the fetlock joints and flexion at the level of the carpus. Thoracic lifts are performed three times per week to maintain thoracic mobility in a ventral direction. This is achieved with pressure applied in a ventral direction to the sternum with the pads of the fingertips until a lift of the thoracic spine is observed.

Physiotherapy takes place every 12 weeks in which stride length, muscle tone, symmetry and joint mobility are assessed and treated accordingly.

Conclusion

The effectiveness of specific training modalities on core recruitment and ultimately recovery are not easily objectively measured in the field setting. However, this outlined case study demonstrates how progressive exercise can be clinically reasoned and applied to a post operative treatment plan in the management of post operative, surgically corrected over-riding dorsal spinous processes.

References

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Henson, F. and Kidd, J. (2009). Overriding dorsal spinous processes. In: Henson, F. Equine Back Pathology: Diagnosis and Treatment. Oxford: Wiley-Blackwell. 147-157.

Henson, F. (2009). Equine Back Pathology: Diagnosis and Treatment. Oxford: Wiley-Blackwell.

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Jeffcott, L. (1980). Disorders of the thoracolumbarthorocolumbar spine of the horse – a survey of 443 cases. Equine Veterinary Journal. 12, 197-210.

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Wakeling, M., Barnett, K., Price, S., Nankervis, K. (2006). Effects of manipulative therapy on the longissimus dorsi in the equine back. Equine and Comparative Exercise Physiology. 3(3), 153-160.

Walker, V., Dyson, S., Murray, R. (2013). Effect of Passoa training aid on temporal, linear and angular variables of the working trot. The Veterinary Journal. 198, 404-411

Walmsley, J., Pettersson, H., Winberg, F. and McEvoy, F. (2002). Impingement of the dorsal spinous processes in two hundred and fifteen horses: Case selection, surgical technique and results. Equine veterinary Journal.  34, 23-28.

Zimmerman, M., Dyson, S. and Murray, R. (2012) Close, impinging and overriding spinous processes in the thoracolumbarthorocolumbar spine: The relationship between radiological and scintigraphic findings and clinical signs. Equine veterinary Journal. 44(2), 178-184