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Review Article: Assessment and Management of Acute Spinal Disease

Introduction

Signs referable to acute spinal cord disease are a relatively common presentation in general practice.  Accurate initial assessment and appropriate early management of such cases can be very rewarding and lead to a good outcome in the majority of cases.  This article reviews our initial approach to such cases and summarises optimal management based on current recommendations, as well as outlining the likelihood of a successful outcome for the more commonly encountered conditions.  Hopefully, armed with this information, you can give your clients a timely prognosis, with a range of treatment options, pending further investigations.

History and Signalment

fig.1 - sagittal T1W MR-scan of Hansen type I thoracolumbar disc extrusion in a Dachshund

These are very important when forming a list of likely differential diagnoses; a young/ middle age Dachshund with progressive paraplegia over a few days is very likely to be suffering from a thoracolumbar disc extrusion (fig.1, click to enlarge), which may well benefit from early, decompressive surgery, whereas a similarly aged greyhound with a per-acute onset would more likely be suffering from a ‘type III’ cord contusion injury to the cord which would normally be managed without surgery.  Similarly, the location of the lesion can often point towards the most likely differential as disc disease is often present in the thoracolumbar and cervical region of the spine.  Note: the presence or absence of pain is not a reliable indicator of the type of disease process present or indeed the severity; both surgical and non-surgical conditions may involve inflammation or irritation of nerve roots to varying degrees.

Initial Assessment and Treatment

Is it neurological?  Beware iliac thrombus/ bilateral orthopaedic disease may present in a similar fashion to spinal cord disease.  Shock and concurrent metabolic disorders may also complicate the neurological exam; it is always worth considering a quick blood biochemistry and administering intravenous fluids before repeating the neurological assessment.  IVFT also helps to minimise secondary changes within the cord which can result from poor perfusion due to shock or dehydration; uncorrected hypotension can result in reversible cord contusion progressing to irreversible malacia.  However, caution should be exercised when administering shock rates of fluids intravenously to patients which may be suffering from congestive heart failure.

Use of steroids

We currently do not advocate the routine use of ‘mega dose’ (30mg/kg methylprednisolone) steroids to treat acute spinal cord disease.  Anti-inflammatory doses (0.5mg/kg prednisolone) may be helpful as part of a multi-modal approach to analgesia, but steroid should ideally be withheld until a diagnosis has been made (CSF analysis may be required, and can be influenced by the previous administration of steroid).  It is better to consider the use of opiates in the acute, painful patient, or low doses of medetomidine/ ketamine, provided there are no complicating cardiovascular factors.  If steroid side-effects are encountered, then mucosal cyto-protectants such as Sucralfate, misoprostol (Cytotec) and ranitidine should be considered.

Survey radiology

fig.2 - lateral cervical spinal radiograph revealed minimally displaced fracture to the body of Ce2.

fig.3 - transverse T2W MR-scan of Ce2 vertebra, reveals fracture of the left pedicle/ articular process.

Ideally, all acute spinal patients should have survey radiology of the affected region of the spine to rule out obvious pathology, such as traumatic fracture/ luxations or lytic/ productive bone lesions indicative of neoplasia or infection (see figs. 2 – 5).  In addition, consideration should be given to imaging the chest and abdomen for evidence of concurrent trauma and/ or metastatic disease.  However, it is imperative that patients are adequately stabilised prior to general anaesthesia and that adequate support of the spinal column is provided as a loss of ‘muscle-splinting’ will inevitably occur as a consequence of anaesthesia.  It should also be emphasised to clients that survey radiology (and indeed myelography) may fail to provide sufficient information on which to base a judgement as to whether the case requires surgery or not.

Consideration might also be given to the anticipated ‘diagnostic yield’ of survey radiology, particularly in cases where possible neuroimaging and surgery could exceed any insurance limit.  However, it is better to fully counsel clients on the cost/ benefit of any procedure and the likely consequences of anticipated findings in order to properly obtain informed consent.

Grading the injury – prognosis

fig.4 - lateral radiograph of cervicothoracic spine - there is subtle remodelling of the pedicle of T2

Spinal lesions may be graded on initial assessment according to their severity;

              grade I – spinal pain exhibited but no neurological deficits.

              grade II – reduced conscious proprioception with variable ataxia and/ or paresis of one or more limbs.

              grade III – non-ambulatory, but retains control of bladder function.

              grade IV – loss of voluntary bladder function (NB beware overflow—the bladder should empty completely with voluntary control.  Also, any lesion cranial to T3 will be grade III or better as grade IV & V lesions would usually result in respiratory arrest).

              grade V – conscious pain perception absent caudal to the site of the lesion.

fig.5 - transverse STIR-weighted MR-scan of T2 reveals extensive destruction of the right pedicle of the vertebra

The most important prognostic indicator for potential cord recovery is the presence or absence of conscious pain perception (aka ‘deep pain’) distal to the lesion.  If the lesion is due to trauma, it is extremely unlikely that a return to walking will occur in grade V cases.  If the lesion is disc-related approximately 50% of cases will show a return to walking provided the cord is decompressed within 48h of the loss of conscious pain perception. 

It is important that the test for conscious pain perception is carried out and interpreted correctly, and that it is repeated on a regular basis; it is worth giving the patient 24 hours on fluids to see if conscious pain perception returns before issuing a guarded prognosis.  To perform the test, squeeze the tibia with substantial bone-holding forceps until the patient vocalises or turns in response.  Note – withdrawal of a pelvic limb in response to testing is an indicator that the spinal cord is intact at the level of the lumbar intumescence and not proof of an intact sensory pathway across the lesion.

Please also note that the presence of the Schiff-Sherrington sign (increased thoracic limb tone when patient is in lateral recumbency, with a lesion caudal to T3) is not a prognostic indicator but merely confirmation of cord injury (grade III-V), caudal to T3, resulting in ascending disinhibition.

Summary

We hope that this information proves useful the next time you are presented with a case that has ‘just gone off its legs’.  However, if you are still unsure, then please feel free to contact us for advice!