39 The Decision-Making Process: A Reprise
39.1 Clinical Decision Making and the Biomechanical Basis for Construct Failure
Clinical decision making is the ultimate focus of this book. An appreciation of anatomical and clinical correlations and the attainment of a deep understanding of biomechanical principles are critical regarding one’s ability to craft rational approaches to care. With this in mind, it goes without saying that the aforementioned form the basis for the prevention of construct failure and for clinical success. Hence, if one understands the biomechanical basis for construct failure, construct failure becomes much less likely.
This chapter, the final chapter of this book, focuses on three components of the clinical decision-making process: (1) the derivation of a sound clinical plan, (2) the appreciation of anatomical and clinical correlations, and (3) the biomechanical basis for construct success or failure. Case scenarios are presented to illustrate the principles and strategies employed to derive clinical plans and to determine the biomechanical mechanisms of failure, when such occurs. Finally, selected scenarios are presented to illustrate the principles relevant to decision making. The scenario categories include the following: (1) the decision to perform a ventral, dorsal, or combined procedure; (2) the decision regarding the site of deformity correction; (3) the decision regarding the determination of the most appropriate trajectory for surgical intervention; (4) the decision regarding the extent of surgery; and (5) the impact of stereotactic radiosurgery on the surgical decision-making process in patients with metastatic cancer. Clinical scenarios for each of these categories are used to discuss the derivation of sound, biomechanically relevant clinical plans. Finally, complication avoidance, as it relates to construct failure, is emphasized.
We begin this final chapter with a discussion of the process involved in making clinical decisions. We then delve into the nuances of the process.
39.2 The Decision-Making Process
All of us make many decisions each day. Perhaps the most important of these are the ones that affect the lives of others. This is particularly so for surgeons. In this regard, the most appropriate decision choice is rarely unequivocal and truly obvious. Frequently, decisions made with the best of intentions are met with legitimate criticism in retrospect. Far too many people (surgeons in particular) use the “retrospectoscope” to judge others who, by virtue of being in the “hot seat,” were forced to make decisions prospectively and without the advantage of hindsight. In this vein and complicating the decision-making process, it is exceedingly common for spine surgeons to differ regarding their clinical opinions. Perhaps both fortunately and unfortunately, there seldom exists a true right or wrong way.
In spine surgery, the decision-making process is indeed complex. It is imperative to understand the fundamentals of operative and nonoperative intervention. The roots of these fundamentals—spine biomechanics and the clinical application of biomechanical principles—have been presented in the preceding chapters. A surgeon cannot “instruct” another surgeon regarding the best way to assimilate this information in order to make optimal decisions. Situations and patients are unique, dictating the need for case-specific thought and creativity. More importantly, chance enters the equation. Two apparently identical patients may respond differently to seemingly identical clinical interventions. Although these different responses are more than likely related to variables that are not as of yet defined, the medical community must, until shown otherwise, attribute them to chance, or rather to the impact of undetermined variables. It is with this in mind that this chapter provides some food for thought regarding decision making and the process by which decisions are made.
39.3 Spine Surgery versus Nonoperative Management: Back Pain as the Paradigm
The surgical decision-making process first involves the decision of whether or not to operate. This is a key and critical decision that is all too often inappropriately made. For the patient who has undergone several unsuccessful operative interventions, the most important surgical decision was indeed the decision to operate in the first place—that is, the decision to perform the first operation. After the first operation, a return to the preoperative state is impossible. “One can always do spine surgery, but one can never undo spine surgery.” Although this admonition is intuitive and obvious, it is often forgotten or not applied. Not all pathologies or pathologic processes respond to surgical intervention, and the surgical intervention itself may, and often does, lead to more spine surgery. The phrase “spine surgery begets spine surgery” is unfortunately “bigger than life” in the current surgical and technologic era.
To facilitate the discussion of the decision-making process, the management of back pain is used as an example. The nonoperative and operative decision-making dilemmas and decisions associated with back pain are particularly illustrative and so are used here as a tool to illuminate the nuances associated with the decision-making process. Such can also help us establish a template for the decision-making process with other conditions.
39.3.1 Back Pain: Defining the Clinical Disorder
A clinical disorder or condition must be clearly defined before a reasonable treatment strategy can be established. Although intuitive, this principle is commonly misapplied, perhaps most notably in the management of back pain.
For example, the etiology of back pain is heterogeneous. Pain in some patients is related to muscle spasm, or a myofascial disturbance. Pain in others may be related to dural or neural compression. In still others, inflammation may be at play (i.e., inflammatory back pain, also known as early-onset ankylosing spondylitis). And finally, pain may be mechanical in nature, with a myriad of associated potential etiologies.
Although the aforementioned scheme perhaps represents an oversimplification, it is used here in order to avoid the intricacies and controversies of diagnosis and categorization that a more complex scheme would entail. Each of the four categories of pain is presented and discussed.
Myofascial Pain
Muscle spasm (myofascial pain) and related entities are the most common cause of back pain. The pain is usually sharp and associated with palpable tenderness of the paraspinous muscles. It seldom responds to bed rest (spinal unloading).
Pain Caused by Dural and Neural Compression
Dural, particularly ventral dural, compression (Fig. 39.1) can cause axial and referred pain (as a result of the relatively rich ventral dural innervation), whereas nerve root compression causes radicular pain. Radicular pain is usually sharp and electric. Axial pain is usually dull and agonizing.
Inflammatory Back Pain
Inflammatory back pain is more common in persons younger than 40 years of age. It is worse upon wakening and dissipates as the morning progresses. Its character, although not the time frame in which it occurs, is similar to that of mechanical back pain. It therefore behooves the surgeon to pursue the diagnosis of both of these conditions aggressively. Inflammatory back pain, which is characteristically seen in patients with early-stage ankylosing spondylitis, is not effectively treated by fusion. Hence, misdiagnosing early-stage ankylosing spondylitis in a patient with back pain as mechanical back pain can lead to a very poor outcome following ill-advised surgical intervention.
Mechanical Back Pain
Mechanical pain is typically deep, dull, and agonizing. Muscle tenderness is not a component of this pain type, although it may be an associated symptom. Mechanical pain is worsened by activity (loading) and diminished by unloading (e.g., bed rest). It is often associated with degenerative disease of the spine (i.e., a dysfunctional motion segment; Fig. 39.2).
Chronic Pain
Chronic pain is defined primarily by its “chronicity.” Although it may have begun as an acute pain syndrome, such pain develops a life of its own as time passes. It also changes character, often being associated with nonradicular and atypical pain. The complaint of “burning,” for example, is often a chronic pain symptom. It is often associated with multiple other, unrelated somatic complaints.
As stated, the pain is usually nonradicular and is not mechanical in nature. The imaging findings may or may not show pathology that is amenable to surgery. Of perhaps the greatest importance is the observation of chronic fatigue (low energy level) with an accompanying sleep disorder in many of these patients.
39.3.2 Management
Each of the aforementioned types of pain is managed differently. Only one (i.e., pain caused by dural and nerve root compression) responds to decompressive surgery, and only one (i.e., mechanical pain) is amenable to spine stabilization with fusion/instrumentation, so that the surgeon can at least hope to achieve success.
Myofascial pain (muscle spasm) responds to “tincture of time,” muscle relaxants, and stretching exercises. It may be prevented by a core muscle–strengthening exercise program. These exercises strengthen the supporting muscles of the spine (e.g., rectus abdominis and erector spinae muscles; see Chapter 37). This pain type is usually self-limiting, but it often recurs if preventative exercises are not instituted.
Dural and neural compression often responds to “tincture of time” and anti-inflammatory agents. Decompressive surgery (e.g., discectomy or laminectomy) may be appropriately performed in selected cases.
Mechanical pain is akin to the pain caused by hip or knee arthritis in patients with severely degenerated joints. It is, in a sense, a manifestation of the wear-and-tear phenomenon (a worn-out joint). Joint removal and replacement (as applied to hip or knee degenerative disease) or fusion (as applied to intervertebral joint degeneration) should eliminate the cause of the pain. What is learned from this analogy is that pain itself is managed by removing the source or by stabilizing (i.e., with fusion) the motion segment (i.e., preventing abnormal or dysfunctional motion).
Regarding the decision-making process, it must be understood that joint stabilization can be achieved by nonoperative as well as operative means. Surgical techniques for fusion and stabilization are well described. Nonoperative management strategies are less well understood. However, they are most certainly capable of effectively contributing to the management of mechanical pain. Flexibility exercises can decrease fibrous adhesions in adjacent motion segments, thus effectively alleviating the restricted range of motion and decreasing the pain related to the stiffened spine. Strengthening exercises can stabilize joints (see Chapter 37). This decreases the mechanical component of the pain syndrome. Therefore, aggressive attempts at nonoperative management should include both stretching and strengthening algorithms (i.e., spine reconditioning).
39.3.3 Patient Selection
Currently, the process of patient selection for both operative and nonoperative management algorithms is relatively unscientific. The surgeon must therefore rely on intuition, existing scientific information, and most importantly common sense. Most spinal disorders can be managed nonoperatively. Therefore, a patient-specific nonoperative strategy should be crafted and methodically employed in nearly all patients with back pain. Failure of such a nonoperative strategy may be construed as one of the indicators in favor of surgery in an otherwise appropriate candidate. A general rule of thumb is clearly applicable here: surgery should be considered only for those patients who have met strict criteria, and whose symptoms and findings would cause the surgeon to undergo surgery in similar circumstances.
One must remember, however, that a failure of nonoperative management in and of itself does not constitute an indication for surgery. Put another way, one should never assume that since “nothing else has worked, surgery will. ”
Indications for Surgery
Indications for surgery include the following: (1) threat of paralysis or death and (2) failure of previous reasonable trials of nonoperative management in patients for whom surgery is a reasonable alternative strategy. There are many contraindications to surgery, including these: (1) the absence of an indication for surgery (the most obvious), (2) medical contraindications (usually related to comorbidities), and (3) success with a nonoperative alternative. Prudence and the liberal use of common sense are emphasized. The overuse of diagnostic algorithms that increase the rate of surgery may not be prudent. An example in this regard is associated with discography, which is relatively unreliable regarding the prediction of clinical outcome. 1 Algorithms for determining outcome with discography are therefore suspect. 2 On the other hand, discography can be used to “weed out” patients from surgical consideration. If used in this manner, discography takes on a different “diagnostic light.”
Philosophy
Physician and even institution philosophy plays a role in the clinical decision-making process. Physician philosophy should (1) be established and (2) be based on a sound foundation of evidence (when available) and common sense. Category-specific algorithms can be generated, adhered to, studied, and redefined (based on study results). This process can be formal or, as is most often the case, informal.
39.3.4 The Decision to Operate
Nonoperative strategies have been addressed in Chapter 37. Further discussion is warranted, however, regarding the decision-making process. The determination of surgical indications is the most difficult and yet the most important aspect of every surgical discipline. This may be most evident in spine surgery, especially with regard to the indications for spinal fusion. There are no official rules to guide patient management. Hence, uncertainty, confusion, and misinformation often prevail. Nevertheless, the use of a logical patient management scheme should optimize the outcome for any given patient. Such a scheme is presented here.
The following presents a scheme used by the author. This scheme is based largely on observations and opinion. Surgeons may or may not choose to incorporate part or all of this scheme into their own decision-making scheme. Nevertheless, the consideration of such a scheme may be instructive and help surgeons devise their own strategic plans.
Indications for Lumbar Fusion
Spinal fusion may be indicated when excessive or abnormal spinal motion causes refractory pain that significantly interferes with the activities of daily living in patients who are motivated and who are actively participating in their own rehabilitation and recovery program. This surgical indication scheme is difficult, if not impossible, to quantitate. General rules of thumb, however, can be established on a surgeon-specific basis. Surgeons should determine their own well-defined and methodically conceived criteria. In the author’s opinion, spinal fusion is indicated if, and only if, the following four conditions are clearly established: (1) Excessive or abnormal segmental spinal motion exists, (2) this motion is related to the patient’s pain, (3) the pain significantly interferes with the activities of daily living, and (4) the patient has demonstrated a commitment to his or her management and recovery process.
Excessive or Abnormal Spinal Motion
Confirming that a spinal motion segment is the cause of a pain syndrome (pain generator) is truly a most difficult, if not impossible, endeavor. Findings on plain radiography, magnetic resonance (MR) imaging, computed tomography (CT), bone scanning, and discography have been used as imaging criteria for spine surgery. Internal disc degeneration or disruption is often touted as a cause of pain of spinal origin. Its diagnosis by discography or MR imaging, however, has not been shown to correlate with clinical outcome. CT, similarly, does not provide clinical correlation. Bone scanning, although appealing regarding its ability to define regions of “inflammation,” similarly does not correlate with surgical outcome.
Because surgical outcome is not correlated with traditional “outcome assessment parameters,” the surgeon should perhaps seek surgical indicators that shrink, rather than expand, the indications for surgery. The painful motion segment that is unstable, excessively mobile, or excessively degenerated should theoretically become painless if immobilized. The unstable motion segment can most often be effectively identified by plain radiography (including flexion and extension X-rays). Its relation to pain can be gleaned from the patient’s history and clinical assessment.
The radiographic findings associated with painful motion segments are (1) excessive mobility, (2) fixed subluxation or other segmental deformity, and (3) significant segmental degenerative changes. These findings suggest that excessive or dysfunctional spine motion exists. Put another way, fixed spinal deformity or excessive degenerative changes in and/or around a disc interspace indicate that abnormal segmental motion exists or has existed. Therefore, even in the face of an inability to demonstrate excessive motion by flexion and extension views, these findings may be associated with pain of spinal origin. This pain, for lack of a better term, is defined as mechanical back pain. It results from mechanical instability and dysfunctional segmental motion. Note that the painful motion segment cannot be unequivocally localized, nor can it be unequivocally distinguished from other, similarly radiographically involved motion segments. It is emphasized that the intervertebral disc is not the only component of the motion segment that may be contributing to the motion segment’s dysfunctional nature. The facet joints can and often do contribute to such. The obligatory multifactorial nature, from an etiologic perspective, adds to the complexity of the diagnostic and decision-making processes.
Clinical Assessment
The clinical assessment is the most important aspect of the surgical indications determination process. It includes an accurate documentation of the patient’s history and the performance of a physical examination. The patient history is important on two accounts. First, it establishes the history to date and the chronicity of the process. More importantly, it elicits the character of the pain. Establishing the character of the pain is a key concept in the surgical indications determination process.
Pain associated with mechanical instability is identifiable by three defining criteria, all of which are required to establish the diagnosis: (1) The pain is deep and agonizing; (2) the pain is associated with activity or loading of the allegedly painful motion segment; and (3) the pain is decreased or eliminated by unloading of the spine (i.e., the allegedly painful motion segment).
Before the presence of pain associated with mechanical instability (mechanical back pain) can be established, other components of the patient’s pain syndrome must be either eliminated or accounted for by both clinical means and imaging techniques.
Extent of Pain
The extent of pain is difficult to quantitate. Usually, it cannot be effectively assessed during one office visit. The surgeon must take adequate time to “get to know” the patient and family. Questionnaires, including outcome assessment instruments and psychosocial assessment tools, may be useful in the process of assessing disability and quality of life and establishing guidelines for treatment algorithms. 3 , 4
The assessment of pain must also involve a determination of chronicity. Chronic pain often does not respond to conventional decompression or stabilization techniques. Managing such pain via a multidisciplinary approach is mandatory. The team must address not only the pain, but also the fatigue and sleep disturbance that are often associated with such pain syndromes. Spinal cord stimulation may even be indicated in a very selected subset of patients. 5
Patient Motivation
Identifying a motivated patient is more straightforward than quantitating the patient’s pain. In fact, motivation may be objectively assessed, albeit indirectly. Several parameters can be monitored periodically to assess progress with a nonoperative treatment regimen: (1) cessation of smoking, (2) weight loss, (3) flexibility parameters, and (4) exercise tolerance and conditioning. Midlevel health care providers (nurse practitioners, physician assistants, and physical therapists) can play a pivotal role in this process, as well as in patient education.
The Last Hurdle before Surgery: Aggressive Nonsurgical Management
Four separate management techniques (constituting a four-point program) are an integral component of the nonsurgical management of mechanical back pain: (1) general augmentation of physical well-being, (2) aerobic exercise, (3) stretching exercise, and (4) strengthening exercises (GASS). Each of these requires patient education by the surgeon, by midlevel health care providers, or more appropriately by both (see Chapter 25).
39.3.5 Alternative Nonsurgical and Diagnostic Strategies
Bed Rest and Traction
Assumption of the horizontal position for prolonged periods is often not beneficial and potentially medically harmful. Therefore, unless otherwise dictated (e.g., quadriplegia and spinal instability), only short periods of bed rest should be considered.
Traction has limited application. Its use is usually restricted to patients with an unstable spine. Other indications should be considered suspect.
Spinal Bracing
Bracing may be indicated for (1) stabilization or (2) diagnostic purposes. If stabilization is the indication for a bracing strategy, its pitfalls and the alternatives to bracing must be considered (see Chapter 36). If diagnostic information is sought, the information gleaned should be sparingly and carefully incorporated into the decision-making process. Spinal bracing may temporarily stabilize the spine and result in a temporary relief of mechanical back pain. 6 A surgical fusion may be indicated if (1) the indications for surgery are present and (2) the patient has failed aggressive nonoperative strategies. An aggressive approach to nonoperative management includes the use of external fixators for diagnostic purposes. 7 More rational approaches to nonoperative management include aggressive physical restoration, core strengthening, and flexibility programs.
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