Neuromobilization Techniques: Evaluation and Treatment of Adverse Neurodynamic Tension and the Container

M. Geraci

M. Lambert

J. Bogulski

Introduction

The examination and treatment of adverse neurodynamic tension (ANDT) is a topic pioneered and extensively researched by Elvey,¹ Butler,² Shacklock,³ and Slater.⁴ Shacklock, Butler, Slater, and colleagues have presented their work at numerous workshops and courses offered by the Neuro Orthopaedic Institute (NOI) around the world. Each of these authors has aided in presenting the concepts discussed in this chapter as well as the clinical use and implications for physical therapists and physicians who treat musculoskeletal disorders. Greenman, Bookhout, Geraci, and Lambert⁵ combined the examination and treatment of ANDT and neuromobilization techniques with manual therapy interventions and therapeutic exercise. The examination and treatment of ANDT has been widely researched by clinicians and anatomists.²^,⁶^,⁷^,⁸^,⁹^,¹⁰^,¹¹^,¹²^,¹³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸^,¹⁹^,²⁰^,²¹^,²²^,²³^,²⁴^,²⁵^,²⁶^,²⁷^,²⁸^,²⁹^,³⁰^,³¹^,³²^,³³^,³⁴^,³⁵^,³⁶^,³⁷^,³⁸ Additionally, Butler³⁹ dedicated a chapter in his book, The Sensitive Nervous System, to the topic of neurodynamics and research.

This chapter will discuss the general concepts pertaining to ANDT including the aim of treatment, consequence of mobilization of the nervous system, precautions, and contraindications. For the experienced clinician, correctly differentiating ANDT from non-neural tissue contributions, such as muscle tightness, joint dysfunction, and joint capsular patterns, is a difficult skill. Accurate diagnosis of ANDT requires the clinician to have a thorough understanding of the slump and straight leg raise (SLR) tests, as well as sensitizing and relieving motions, to differentiate the presentation of hamstring tightness from ANDT of the sciatic nerve or one of its nerve roots.

After completing testing for ANDT, the clinician must address the non-neural or “container” structures that contribute to the patient’s presentation. This chapter will address why these tissues must be targeted before intervening with neuromobilization techniques. In the lower quarter, addressing lumbar segmental dysfunction, sacroiliac/pelvic dysfunction, capsular patterns, and muscular tightness must be treated first to achieve a successful outcome for the patient with ANDT. Femoral nerve ANDT and its associated nerve roots must be differentiated from tightness of the rectus femoris. With this nerve, treatment of the container involves addressing upper lumbar segmental dysfunctions, sacroiliac/pelvic dysfunction, and capsular tightness of the hip, specifically the anterior capsule. Commonly, lack of muscular flexibility of the psoas and rectus femoris is commonly associated with a tight anterior hip capsule. This concept will be discussed in detail later in the chapter.

The upper quarter requires the clinician to differentiate between rib dysfunctions and muscular tightness patterns from ANDT of the median nerve. In this chapter, detailed descriptions of the upper limb neurodynamic tests (ULNTs), formerly known as upper limb tension tests (ULTTs), will be discussed in detail as well as the clinical implications for examination and treatment. Additionally, clinicians must understand how ULNTs can be used as a measure of progress and an intervention strategy after the container structures have been addressed. The upper quarter container includes identifying patterns of inflexibility of the scalene muscles, pectoralis minor muscle, and long head of biceps muscle/tendons and their relationship to first through fifth rib dysfunction. Stretching of the teres major, latissimus dorsi, and posterior shoulder capsule tissues also need to be addressed in the examination and treatment of the container. Segmental dysfunctions of the cervical and thoracic spine should be addressed based on examination findings. Following treatment of these structures, ULNT should be reassessed to determine if treatment of the container structures caused a change in ANDT.

This chapter requires the reader to familiarize himself with Butler’s works¹¹^,³⁹ as referenced by other authors in this text. A baseline understanding of the work of Butler is essential to understand that a complete examination and treatment of ANDT incorporates manual therapy techniques to correct joint dysfunctions, including manual stretching for tight muscles and joint capsule restrictions. Due to the fact that daily function occurs in a combination of two or more planes, three-dimensional (3-D) self-stretching and functional exercises have been shown to help maintain the correction of joint dysfunctions and prevent recurrences by reinforcing quality movement during functional activities. Many of the treatment techniques in this chapter have been updated from the last edition.

General Concepts

Neurodynamics, as defined by Shacklock,³² is the mechanisms and physiology of the nervous system as related to one another. The term pathodynamics refers to abnormal mechanical, physiologic, and symptomatic responses produced from nervous system structures when their mechanics are tested. The nervous system is designed to allow for movement and symptoms arise
for patients when motion is restricted. The spinal canal allows for up to a 7-cm difference in length when comparing spine flexion and extension. Most of this length is contributed by the cervical and lumbar regions. Nee and Butler⁴⁰ stated that neural mobilization techniques are designed to restore the ability of the nervous system to tolerate the typical forces exerted on the nervous system during daily and sporting activity.

During patient examination, the clinician should begin by assessing the asymptomatic side to appreciate the resistance of tissues during neural excursion, any reduction in range of motion as the joints are sequentially loaded, and change in symptoms with the use of sensitizing or relieving motions. On the symptomatic side, the clinician should be assessing for the resistance of tissues, reduced range of motion as well as reproduction of symptoms in at least some area of the patient complaint, and change in symptoms with the use of sensitizing or relieving motions.⁴¹ Additionally, Butler recommends the clinician may consider altering the neurodynamic testing sequence to replicate the functional complaints of the individual to assess the difference between the modified and standard sequence.³⁹

The nervous system is designed to resist stress (compressive, tensile, or shear forces), strain (longitudinal tensile loads), and excursion (gliding of nerve in surrounding sheath). The peripheral nervous system shows significant lengthening changes as you move from wrist and elbow flexion to wrist and elbow extension requiring the median nerve to adapt to a nerve bed that is 20% longer. A clinician must determine the appropriate parameters for application of intervention when addressing issues with ANDT. Considerations for appropriate prescription of neural mobilization include patient phase of healing, ongoing assessment of patient presentation, and consideration of the functional activities causing symptoms.⁴²^,⁴³^,⁴⁴

Impact of Forces on Blood Supply

When determining the amount of load to apply to neural structures, you must first consider the implications of the applied loads. The literature states that nerve elongation of 8% causes a reduction in blood flow to the tissues; however, there does not appear to be long-lasting effects present at that load once tension is removed.⁴⁵^,⁴⁶ Elongation applied to peripheral nerves exceeding 11% interrupts blood supply and may cause long-term damage due to excessive tissue stress.²⁷^,⁴⁵ Additionally, researchers have demonstrated that a constant strain to neural tissues can cause ischemia during force application followed by a reperfusion injury due to an inflammatory response once the stress is removed.⁴⁷^,⁴⁸

Pressure Changes

Mobilization of the nervous system is accompanied by pressure changes.⁴⁹ Depending on the technique selected, slider versus tensioner, and the joint(s) moving can cause substantial changes in pressure within the nerve. The literature shows that sliding techniques cause the greatest nerve excursion with the least amount of pressure increase while tensioning techniques result in the smallest nerve excursion.⁴²^,⁴³ Additional consideration during tensioning techniques is the amount of nerve excursion and tissue strain occurring at the moving joint. For example, performing wrist movement with the elbow in extension for the median nerve strain increases by 3%, whereas wrist movement with elbow flexed to 90 degrees causes an increase in strain of 9.5%.⁴²

Phase of Healing

The clinician must identify the phase of healing in which the patient presents to effectively intervene. Currently, the literature is unclear as to appropriate parameters for nerve mobilization.⁴²^,⁴³^,⁴⁴ Recommendations have been made to follow the Maitland grades for joint mobilization³⁶^,⁴⁴^,⁵⁰ using grades I and II for individuals presenting in the inflammatory phase to mitigate pain and grades III and IV for individuals presenting in the proliferation to return to function phase to improve range of motion. However, Elvey recommends avoiding the use of end range grades⁵¹ and Butler suggests initial treatment sessions should last no longer than 20 to 30 seconds for each motion being addressed.²^,³⁹

Treatment Recommendations

Based on the above research and recommendations, following the patient response model and use of on/off nonballistic and proprioceptive neuromuscular facilitation (PNF) style techniques reduce the risk of causing further harm to these sensitive structures. Additionally, avoidance of positioning a patient in a tensioned neural position as you treat the container will minimize further trauma. Butler and colleagues¹¹^,³⁹^,⁵² discuss the dispersion of intraneural edema, mobilization of neural adhesions, increased blood flow and cerebral spinal fluid flow, as well as axonal transport. Normalizing extraneural interfaces is a consequence of mobilizing the nervous system; however, achievement of this equilibrium is likely best accomplished by addressing the dysfunction of the container first. Lastly, the use of transforaminal epidural steroid injections performed under fluoroscopy with contrast enhancement allows the practitioner to utilize local anesthesia to mobilize the nervous system after application.⁵³

When a patient with ANDT presents with severe symptoms in the affected limb, the clinician must look
at options to begin mobilization of the nervous system safely. The first strategy to mobilize the nervous system is to begin working with one of the other three uninvolved extremities. An example is a patient with a focal, cervical disc herniation, and right upper extremity radiculitis. This patient would not tolerate performing neuromobilization of the involved limb; therefore, the clinician may start by mobilizing the opposite upper extremity. If that strategy is not tolerated by the patient, the clinician could begin treatment of the ipsilateral lower extremity or the contralateral lower extremity. The last alternate technique is rarely needed, but in the case of a patient with significantly reactive tissues, you may apply dorsiflexion and plantarflexion of the contralateral lower extremity as your starting point to mobilize the nervous system. Additionally, in patients with chronic nerve root scaring postsurgically, the examiner may find symptoms are reproduced on release of the tension test. This often times represents intraneural scaring and effective intervention requires the selection of tensioners for neuromobilization.

Special Treatment Considerations In the past several years, Kolski and O’Connor (Table 22.1) have advocated using the Pain Mechanism Classification System, subcategory Peripheral Neurogenic, for classifying a nerve as either being trapped, tight, or sensitive. This more specific subclassification of a nerve’s character will in turn allow for more specific treatment when deciding when to use sliders or tensioners or even when certain medication will be most effective. The neuromobilization most appropriate for a trapped nerve would be sliders, for a tight nerve tensioners, and for a sensitive nerve sliders. The sensitive nerve may have abnormal impulse-generating sites (AIGS), and it is for this reason that medications, such as gabapentin and pregabalin, can be very effective.

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