Patients with Multiple Surgeries

15
Patients with Multiple Surgeries

Claudio Lamartina and Carlotta Martini

■ Introduction

A growing issue among spine surgeons is the management of the increasing number of symptomatic spine patients who have had multiple surgeries for treatment-resistant pain that has contributed to an unacceptable quality of life.

There are several possible explanations for this phenomenon:

The progressive aging of the population and the subsequent increasing number of surgeries for degenerative spine, even on the same patient
A propensity for spine surgeons to recommend spine surgery rather than conservative measures
The difficulty in identifying pain generators, as a result of the widespread emphasis on imaging techniques. Diagnosis should be based on both a clinical evaluation and imaging.

Revision surgery is a more and more frequent procedure in spine units; these patients tend to be older, thus adding risks related to comorbidities. From a psychological point of view, patients who have experienced repeated surgeries frequently feel hopeless and have a negative attitude toward surgery, making it difficult for surgeons to determine which patients are appropriate for surgery. Patients’ expectations are often unrealistic, as their pain has been of long duration and spine surgery is complex.

Revision surgery is frequently performed by a different team. Thus, patients expect the new surgeon to clear up the errors committed by several previous surgeons, which is unrealistic.

This chapter discusses the issues related to managing patients who have had multiple surgeries, and presents an illustrative case.

■ Case Presentation

A 58-year-old woman with mechanical low back pain and claudication was referred to a spine surgeon, who performed a clinical and radiological evaluation (Fig. 15.1), based on which the surgeon determined that the patient was a candidate for an L3-L4 decompression and L3-L4 translaminar screw, using the Magerl technique. The aim of the surgery was to decompress and stabilize the spine. The patient’s pain was relieved by the surgery, but 1 year later the symptoms returned, worse than before. The patient was unable to walk more than 50 m, after which pain increased in her lower back, buttocks, and proximal legs, bilaterally. X-rays demonstrated a hypermobility of the L4-L5 disk (Fig. 15.2), and the surgeon decided to widen the decompression to L5, and to perform a fusion, including the previously operated segment and extending to the new unstable segment (Fig. 15.3). A pedicular screw is the technique of choice, with posterolateral fusion.

Fig. 15.1 Magnetic resonance imaging (MRI) scan (a) and X-rays of the patient in the presented case before the surgical procedure (b,c). The values of lumbar lordosis measured on MRI sagittal cut and on the X-ray are different. The trick is to determine if the patient is standing or not. The L3-L4 disk space is degenerated and flat, and L1-L2 and L2-L3 are in lordosis (Roussouly type 2 or 3). L4-L5 is slightly hyperlordotic. The lordosis distribution is not respecting the rule of two thirds in L4-S1 and one third in L1-L4.

Fig. 15.2 After first surgery, L4-L5 retrolisthesis is present, and the L3-L4 space is flat and fixed with a translaminar Magerl screw.

Fig. 15.3 (a) After the second surgery, the decompression area is widened, and the fusion is extended, covering L3-L5. L3-L4 is a little more lordotic in the early follow-up, but this small gain is lost at 1-year follow-up (b). L4-L5 is fused in a lordotic position.

The patient’s relief from pain was once again short-term as well as inconsistent. One year later, her pain returned to the preoperative level. The surgeon then decided on conservative treatment, with physiotherapy, multimodal analgesia, and clinical observation. But after another year, the clinical situation had dramatically worsened, as the patient was completely unable to stand or walk for more than few seconds without pain. The patient experienced almost continuous pain that was relieved only by lying down. The first surgeon referred her to a second surgeon.

The second surgeon performed a clinical evaluation, and found a pathological sagittal alignment. The patient’s knees were maintained in a flexed position, her pelvis was retroverted, and thoracic kyphosis was nearly absent. On the frontal plane, a moderate coronal deformity was noted. The surgeon updated the imaging with new whole-spine X-rays with the patient in the standing position to assess the sagittal alignment (Fig. 15.4). The X-rays demonstrated a lack of lumbar lordosis (LL), proximal junctional kyphosis (PJK) in the thoracolumbar area, a high pelvic tilt (PT), a low sacral slope (SS), and a sagittal vertical axis (SVA) > 5 cm. Because the SS was close to 0 degrees, the pelvic incidence (PI) was nearly equal to the PT.

The surgeon decided to revise the previous surgery, extending the previously instrumented area to T10 cranially and to the ileum caudally. The revision was done with a double approach, lateral and posterior. Multilevel extreme lateral interbody fusion (XLIF) cages were implanted at the L1-L2, L3-L4, and L4-L5 levels. At the L2-L3 level, to restore the required lordosis, a hyperlordotic 30-degree cage was implanted, the anterior longitudinal ligament was resected, and the anterior column realignment (ACR) technique was performed. Posterior instrumentation from T10 to the ileum was also performed. Postoperatively, the patient’s condition improved; she was quickly mobilized and was able to stand without experiencing additional pain (except for the expected wound-related pain). The sagittal alignment improved, and she demonstrated normal knee extension, a physiologically normal thoracic kyphosis, improved LL, and a more natural neck and head position.

Fig. 15.4 Radiographic and clinical global assessment of the patient before the last revision surgery. A proximal junctional kyphosis in the thoracolumbar area is present, together with close to a 0-degree sacral slope and a consequent high pelvic tilt (equal to pelvic incidence). Neck hyperextension, a flattened thoracic kyphosis, a retroverted pelvis, and flexed knees are clearly visible in the clinical photos.

The radiographic results, together with a clinical photo, are shown in Fig. 15.5. The patient’s improved condition has continued even at the 3-year follow-up.

■ Case Discussion

Clinical Examination

When a patient with multiple surgeries presents to a new physician, it is important to determine the patient’s chief complaint; if it is back pain, then the pain generator needs to be identified. After a physical examination is performed, imaging with X-rays, magnetic resonance imaging (MRI), or computed tomography (CT), as well as evocative diskography and facet block should help to identify the pain generator and provide additional information. Then the decision of whether to manage the patient conservatively or surgically needs to be made.

Fig. 15.5 Postoperative radiographic and clinical global assessment of the patient. The fusion area is extended from T10 to the pelvis. Lumbar lordosis and thoracic kyphosis are restored, reproducing the hypothesized Roussouly type 2 that the patient belongs to. All the aforementioned compensatory mechanisms are no longer present in the X-rays and clinical photos.

In only 15% of patients does low back pain have an organic cause.1 In the remaining 85%, the cause is unclear. Socioeconomic factors have to be carefully evaluated, and the yellow, blue, and black flags need to be identified (see Chapter 2).

In addition to complaining of back pain, many patients, including the patient in our case presentation, complain of the inability to walk autonomously for more than a limited distance. The ability of the surgeon to differentiate this kind of disturbance from neurogenic claudication is crucial. The case presented above was an example of a patient given a misdiagnosis. When asked about symptoms, during the interview before the last revision surgery, the patient did not describe the typical neurogenic claudication. Rather, her pain was a burning tenderness, radiating from the lumbar region downward to both legs and upward to the dorsal region, starting after walking for a few minutes and remitting with passive extension of the trunk or bed rest. This is quite different from the standard neurogenic claudication, which classically has a different pain quality and remits with trunk flexion or sitting.

We believe that neurogenic claudication should have been the first diagnosis, but the back pain that ensued and persisted after the first surgical procedure was a different matter, as we shall explain.

Imaging

The importance of the evaluation of spinopelvic alignment is widely accepted and evidence-based.2–4 The clinical workup, as described above, and appropriate imaging are fundamental. The routine use of standing, full-spine, plain X-rays is changing the indications for surgery, as demonstrated by a sample of spine surgeons who answered a blinded questionnaire from the AOSpine organization.⁵

We believe that a possible explanation for the failure of the presented case is hidden in the very first imaging (Fig. 15.1). If we carefully review the alignment of the lumbar vertebrae, we can see a nonphysiological distribution of LL. It has been reported that LL in an asymptomatic healthy population has a constant distribution along the lumbar spine: two thirds between L4 and S1, and one third between L1 and L4. This is a simple measurement that anyone can perform on a plain standing lumbar spine X-ray film, as in Fig. 15.1.

Additionally, in a standing X-ray, even if the femoral heads are not visible in the field of view and we cannot measure PI and PT (Figs. 15.1, 15.2, 15.3), the SS is clearly visible. This is a highly informative parameter, especially if it has a very low value. An SS close to 0 degrees (vertical sacrum, as in Figs. 15.3b and 15.4) means that PT is high (pelvic retroversion). The base concept for the understanding of this deduction is in the fundamental equation:

PI (Constant) = PT + SS

If SS is 0 degrees, PI is equal PT, whereas the ideal PT is 0.37(PI) – 7 (Vialle formula⁶). It has been demonstrated that high PT values are correlated with pelvic compensation and poor clinical outcomes. In the presented case, we can see that SS is lower in Fig. 15.2 than in Fig. 15.1. Our interpretation is that after the first surgery, the patient started to compensate actively with pelvic retroversion. The compensation was caused by a loss of mobility and lordosis at the fused level. So the lumbar spine was flatter and less able to fight this forced alignment with the spinal segments.

We know that a normal, flexible spine, has the ability to compensate for the alteration of the expected curves at the different levels.^7,8 This is known for the lumbar and thoracic spine, and under evaluation for the cervical spine.⁹

The ability to compensate is proportional to the degree of deviation from the normal values of curves, and it is limited by any type of fixation, be it artificial or autologous. Whenever the spine is not able to compensate, there are several different mechanisms by which the human body tries to maintain horizontal gaze.¹⁰ Pelvic retroversion is the first mechanism, followed by joint movements in the lower limbs. Compensation mechanisms are sometimes so evident and so obvious that it is sufficient merely to observe the undressed patient; imaging is unnecessary. But the compensation mechanisms are not routinely evident. Most often they are hidden, or are in a very early phase of development, so it is important for the surgeon to recognize the possibility that compensation mechanisms are developing.⁸

All these considerations can be evaluated with a simple standing lumbar spine X-ray and by observing the patient. It certainly could have been possible in the presented case. Thus, in the evaluation of a multi-operated spinal patient, the gold standard is the full-spine standing X-ray.

Correctly measured and reliable spinopelvic parameters enable the surgeon to classify the patient in the correct Roussouly type, and consequently to plan the surgical strategy, aiming to reconstruct a physiological, patient-specific, final alignment.¹⁰

Further examination of the patient’s imaging can also lead to a diagnosis of proximal junctional kyphosis in Figs. 15.3b and 15.4, after the instrumented fusion at L3-L5. As we know from the literature, proximal junctional kyphosis is secondary to under- or overcorrection of LL, to an incorrect distribution of lordosis on the lumbar spine, and to a final excessive PT resulting after surgery.¹¹ Identification of a proximal junction problem should be suggestive of an alignment-related problem, and thus should lead to a careful evaluation of the whole spine.

Surgery

The presented case demonstrates some of the critical issues in reviewing a patient’s previous surgery. A new surgeon has to rely on his or her personal experience and the previous surgeon’s report. Thus, it is important for surgeons to share knowledge and ideas, and to report their unavoidable mistakes.

Surgical indications in low back pain are controversial. Patients often undergo multiple surgeries because of unclear indications for the first surgery, which begins a vicious circle in which patients never have a chance to heal and additional surgeries are performed, often worsening the situation in a negative progression.

Surgical indications should be one of the first issues to be discussed with the patient. It is important to strictly define what spine surgery can do effectively. In the vast majority of cases, there are just three effective surgical functions:

Decompression
Fusion
Deformity correction

Successful spine surgery always aims to accomplish one or more of these functions. The surgeon has to be clear in his or her mind about the aim of the surgery. If the aim is not on this list, the outcome is unpredictable.

In the majority of cases, the aim of surgery is fusion. To reduce nonunion rates, instrumentation is useful. Instrumentation without fusion has a very limited indication, such as for Chance fractures, in which instrumentation in compression promotes the fracture’s healing.

Nowadays, patients are overwhelmed by the availability of medical information on the Internet and in the media. The surgeon should review the information the patient has acquired, and correct any misimpression the patient has, so that the patient does not harbor unrealistic expectations.

A widespread belief among spine degenerative patients is that the greater the pain, the greater the need for surgical intervention. Patients should be informed that this is not true, and given the reason in a fairly detailed way. High preoperative pain levels are related to a worse outcome 12 in every type of spine procedure for degenerative conditions. This fact should be discussed with the patient, together with the low ability of surgery to correct a previous medical error.

Additionally, a thorough description of the surgical risks and possible complications should be presented to patients, to pave the way for their providing their informed consent. Also, patients believe that more extensive surgery results in better outcomes. This misimpression also needs to be corrected, and patients should be told that the more complex the surgery, the greater the risk of complications.

Furthermore, nearly all patients ask for minimally invasive surgery because they read about it on the Internet. This request could lead many surgeons to reduce the goals of the surgery, leading to the potential need for further revisions, when in fact an open procedure could provide definitive treatment without the need for further revisions.

The complication rate in revision surgery for adult spinal deformity is also significantly related to the surgical unit’s experience.¹³ This is an evidence-based fact that confirms the importance of the surgeon’s knowledge and experience. Good results are not easily obtained, so patients who need highly specialized spine surgery should be carefully selected.

The presented case demonstrated all these concerns. Every patient presents a unique scenario, but the most important factors for the surgeon are to observe the patient, review the imaging, do a careful clinical examination, and clearly explain the aims of surgery.

■ Case Resolution

We believe that the aim of the surgery in the presented case should have been the correction of the sagittal deformity, which could have eliminated the need for the compensatory mechanisms that were responsible for the patient’s complaints.

The patient was not able to stand for more than few minutes or walk for more than a short distance without suffering a burning pain in the low back, radiating to the dorsal region and to the proximal lower limbs. This kind of pain is secondary to a sagittal deformity. The sagittal deformity was responsible for the recruitment of compensatory mechanisms to maintain horizontal gaze. The compensatory mechanisms in this case were flattening of thoracic kyphosis, pelvic retroversion, knee flexion, and neck hyperextension (Fig. 15.4). All compensatory mechanisms require muscular effort and produce pain.

Once the surgical aim has been defined, a surgical plan is developed, based on the patient’s anatomy. In this process the starting point is the patient’s PI, in this case 30 degrees, measured for the first time on X-rays (Fig. 15.4). Studies have demonstrated that the expected LL can be calculated from the following formula^14–16:

LL expected = PI ± 10 degrees

In the case of low values of PI, 10 degrees should be added; in the case of high values of PI, 10 degrees should be subtracted. This is a useful formula in that it provides a numerical target value, but the correct expected LL of a patient is not just the result of a formula. Age is another variable that affects surgical planning.^14,17

In the presented case, the PI was 30 degrees, which is a low value, so the expected LL should be at least 40 degrees. The patient is a Roussouly type 2, a “harmonious flat back,”¹⁰ as LL is long and the L1-2-3 disk spaces are in lordosis (Fig. 15.1).

The variation in spinopelvic parameters in the presented patient over time is demonstrated in Table 15.1. Interestingly, the global LL value was constantly decreasing with time, and each surgical procedure worsened it, together with the SS. Consequently, the PT increased.

The loss of upper LL, driving the lower compensation of disks L4-L5 and L5-S1 (Fig. 15.2) should be our main surgical target. Our surgical plan should address this area specifically, and the restoration of a harmonic angular proportion, including the thoracolumbar kyphosis, would be the goal of surgery in order to have a successful and durable result.¹⁸

The surgical plan, then, is to achieve a final LL of more than 40 degrees, with two thirds of it in L4-S1 and one third in L1-L4. Thus, we need at least 15 degrees of lordosis in L1-L4, starting from 35 degrees of kyphosis, which means a global correction of more than 50 degrees within L1 and L4. There are several ways to obtain this result. Our choice is to use lordotic cages in L1-L4 with a hyperlordotic cage in L2-L3 to obtain a single-level 30-degree correction by anterior column realignment,¹⁹ with a double-approach procedure (lateral first, posterior second). The remaining correction of 20 degrees has been distributed on two levels, 10 degrees each on L1-L2 and L3-L4.

The fusion area (T10 to the ileum) involves the thoracolumbar area, as the main surgical target was the high lumbar area and the thoracolumbar junction, as well as the ileum for a more stable construct. It has been considered unnecessary to extend up to the high thoracic area, because the thoracic spine is considered to be flexible, and the thoracic flattened kyphosis has been considered a compensatory mechanism, not a surgical target in itself. This consideration limits the fusion area, which helps reduce the risk of complications.