Perioperative Care of the Lower Extremity Orthopedic Patient With Multiple Sclerosis

W. Mark Richardson

Dale J. Lange

Karen Yanelli

Introduction

Multiple sclerosis (MS) is an immune-mediated disorder that causes a variably progressive neurological condition associated with demyelination throughout the central nervous system. We know much about the pathology of the disease, but there is uncertainty about the cause and the immunological determinants. Biomarker analysis and lesion classification may allow for diagnoses by pathological subtype in the near future.¹

Individuals present with a clinically isolated syndrome (CIS) caused by a lesion of the optic nerve, cerebrum, cerebellum, brainstem, or spinal cord. Subsequent progression, if it occurs, is classified according to standardized McDonald diagnostic criteria.² It is estimated that approximately 70% to 80% of patients with both abnormal radiological findings and a CIS will convert to clinically definite multiple sclerosis (CDMS) over time.³ According to the Multiple Sclerosis Society, there are three disease subtypes: relapsing remitting (RR), secondary progressive, and primary progressive.²,⁴,⁵ These definitions are further refined by the frequency and magnitude of neuroinflammatory
activity and remissions and progression through accumulation of neurological deficits over time.⁶ Most patients are diagnosed with relapsing forms of the disease at an average age of 29 to 30 years, with a range 2 to 70 years. There is positive correlation between age at the time of diagnosis and progressive forms of the disease at its onset.³,⁵ The majority of MS diagnoses are of the RR subtype, which has an estimated 80% likelihood of evolving into the progressive subtype within 25 years of diagnosis of CDMS.³

Patients with MS may require surgery for a variety of reasons. Given the age demographic, young patients often develop musculoskeletal injuries of the lower extremities such as torn menisci and lesions of the ligaments. Older patients with arthritic comorbidities and those with a history of long-term steroid use may require total hip arthroplasty (THA) or total knee arthroplasty (TKA).⁷ Additionally, patients with progressive forms of the disease are at an increased risk of injury due to falls.

Owing to the pathogenic and clinical heterogeneity across patients, optimal management of the perioperative care of patients with MS requires careful planning and a multidisciplinary clinical effort. Any plan for lower extremity orthopedic procedures for patients with MS should account for the variables that, if managed properly, add the most value toward positive perioperative outcomes. These include preoperative neurological and medical evaluation, management of disease-related symptoms, steroid use, prophylactic use of antibiotics, anesthesiological technique, dosing and timing of disease-modifying therapies, and potential rehabilitation requirements. The purpose of this chapter is to organize the knowledge base around these aspects of care for patients with MS and their primary physicians and caregiver in preparation for lower extremity orthopedic surgery.

Preoperative Phase

Although there is uncertainty whether trauma, such as surgery, is able to cause a relapse,⁸ anticipation of this potential is essential in the preoperative and perioperative evaluation of the patients with MS preparing for such procedures. Poor surgical outcomes may arise as a result of poor preoperative management, which may affect postoperative functionality, including risk of fracture in patients with a history of long-term steroid use, cardiovascular complications such as deep vein thrombosis in patients with impaired mobility, and cardiovascular comorbidities due to autonomic nervous system dysfunction.

It is imperative that the preoperative evaluation includes a thorough clinical examination and a review of the history of the patient’s disease to account for the probability of relapse leading up to the procedure, to mitigate the risks of anesthesiological complications, and to predict the patients’ capacity to effectively recover from the procedure, and to plan for rehabilitation.

The review of the history of the disease should include the date of the diagnosis, the disease subtype, symptoms, and their severity. The physical and neurological examinations should rule out an acute exacerbation and evaluate somatic and autonomic function as well as cognitive and psychological status.⁷,⁹ Ambulatory function should be assessed for all patients. Those with a history of bladder dysfunction and urinary tract infections (UTIs) should be evaluated for infection.

Individuals with progressive forms of the disease may have accumulated neurological deficits that cause respiratory dysfunction and cardiovascular irregularities. The accumulated deficits would be associated with lesions in the medulla and spinal cord, which would be revealed on magnetic resonance imaging (MRI). Lesions in these regions may correlate with a respiratory condition, bulbar dysfunction, dysregulation of autonomic nervous system, and respiratory insufficiency.¹⁰ Such patients should have pulmonary function tests administered preoperatively to determine the extent of respiratory dysfunction.¹¹,¹²

Individuals with RRMS who have few residual neurological deficits may not require many resources beyond the standard of care for the general population.⁵ However, it should be noted that onset of initial symptoms and date of a definitive diagnosis of RRMS is positively correlated with frequency of relapse; relapses have been shown to occur at a higher rate during the first years after a diagnosis of RRMS, slowing thereafter.¹³ The preoperative examination should rule out an acute relapse.

Cognitive impairment can be assessed with a variety of tools, including the Symbol Digit Modalities Test and verbal fluency tests. Comorbid depression may affect cognition, prompting the need for tests that distinguish somatic symptoms and mood changes, such as the Depressive Mood Scale or a Beck Depression Inventory Fast Screen.⁹,¹¹

A record of the patient’s disease-modifying therapy program, concomitant medications, and history of steroid usage should be obtained.

Preoperative Symptom Management

Treatment of relapsing forms of MS generally includes immune-modulating therapies, whereas few treatments exist for progressive forms of the disease.³ Of the most common deficits, those that require particular attention and management during the perioperative scope are spasticity, ambulatory dysfunction, fatigue, bladder dysfunction, and depression and cognitive impairment.³

Management of paroxsymal symptoms, such as spasticity, is especially important for optimal outcomes for hip and knee arthroplasty. Many patients with upper motor neuron involvement develop spasticity, which is usually managed with a combination of physical therapy and medications.¹⁴ Common medications used to treat spasticity include baclofen,
benzodiazepines, or tizanidine. If the patient can tolerate it, uptitration of antispasticity medication preoperatively may mitigate the risk of postoperative complications due to increased tone of the lower extremities.⁷,¹⁵ However, as noted later, baclofen is contraindicated with some forms of anesthesia and therefore may not be administered intraoperatively.

A preoperative assessment of any surgical patient’s airway is standard of care when preparing for endotracheal intubations. Patients with MS with surgical histories should have their notes reviewed for any incidence of difficulty with intubation. Given the possibility of paroxysmal symptoms throughout the perioperative period, head and neck range of motion assessment must be included in the preoperative neurological and physical examination. Less than 80° range of neck motion in flexion/extension is a risk factor for difficult intubation.¹⁶,¹⁷

Steroids

If acute exacerbation is encountered in the preoperative period, depending on its severity, treatment with high-dose intravenous glucocorticosteroids (GC) may be necessary. The typical dose given for acute flares is approximately 1000 mg of methyl prednisone daily for 3 to 5 days.³ However, there is evidence that steroids may have a time- and dose-dependent impact on bone metabolism. It is well known that long-term use of glucocorticoids affects bone metabolism and leads to osteoporosis, more generally mediated by well-defined endocrinological mechanisms.¹⁸,¹⁹ Studies show the association between steroids and osteonecrosis of the femoral head and increased risk of bone fracture. The latter may increase the likelihood of injury during positioning throughout the perioperative period.¹³,²⁰,²¹ Sahraian et al (2012) report from their case study analysis that symptoms of avascular necrosis of the femoral head may occur after 6 and 8 months of steroid therapy. Moreover, studies have also shown that short-term administration of high-dose GCs for young patients with RRMS with acute exacerbations may immediately increase bone resorption and decreased bone formation with high turnover after the steroids have been stopped.²²

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