15.3.1 Antecollis

In 1817, James Parkinson first described the disease that bears his name as “a propensity to bend the trunk forward” along with the following physical exam finding: “the chin is now almost immovably bent down upon the sternum.” ^{2 ,​ 3 ,​ 4} Later in 1886, Gerlier used the term “vertigeparalysant” to refer to the phenomenon of a dropped head associated with torticollis and pain of the occipital muscles that spread to the shoulders. ⁵ Meanwhile, in Japan, Miura in 1897 described “kubisagari,” or attacks of dropped head with weakness of the upper and lower extremities. ⁴ These represent the earliest descriptions of antecollis.

Antecollis is defined as significant (minimum of 45 degrees) neck flexion which may be partially overcome by voluntary or passive movement. Severity is variable, with some patients presenting with an inability to fully extend the neck against gravity but able to exert force against the resistance of the examiner’s hand. ^{6 ,​ 7} Antecollis occurs in Parkinson’s disease resulting from dystonia of flexor neck muscles or weakness of extensor neck muscles. ⁴ Antecollis develops in 5 to 6% of patients with Parkinson’s disease, ^{3 ,​ 4 ,​ 8} yet it is also occasionally a component of multiple system atrophy, with shorter intervals between the onset of motor symptoms and antecollis. ⁷

15.3.2 Lateral Axial Dystonia

LAD is a general term used to describe the laterally flexed posture caused by extensor truncal dystonia, also known as pleurothotonus and Pisa syndrome. ^{9 ,​ 10} First described by Ekbom et al in 1972 as a constellation of physical exam findings associated with neuroleptic therapy, ¹¹ Pisa syndrome, reminiscent of the well-known Italian structure, is defined by significant (minimum of 10 degrees) lateral flexion, often with a component of backward axial rotation, that can be alleviated by passive mobilization or supine positioning. ¹² LAD is characterized by continuous electromyography (EMG) activity of ipsilateral paraspinal muscles while standing or seated, though EMG activity is absent while recumbent. ⁹ Despite the often interchanging use of these terms, there is some controversy among authors regarding the etiology of these conditions (i.e., tardive neuroleptic syndromes vs. idiopathic primary dystonia) and possibility that they represent more than one clinical entity.

Pisa syndrome has been described among patients with Alzheimer’s disease, ^{13 ,​ 14} multiple system atrophy, ¹⁵ Parkinson’s disease, ^{6 ,​ 16} and ALS, ¹⁷ as well as in patients with dementia treated with cholinesterase inhibitors. ^{9 ,​ 18} One series of 1,400 patients with Parkinson’s disease demonstrated 1.9% with classic features of Pisa syndrome, ⁹ which may be a precursor to the development of scoliosis in these patients. ^{6 ,​ 9} Though there are documented cases of idiopathic Pisa syndrome, most cases are associated with the use of neuroleptic medications and respond well to adjustments or withdrawal of offending agents. ^{19 ,​ 20}

15.3.3 Camptocormia

In 1818, Sir Benjamin Collins Brodie described a “functionally bent back,” referring to what would later be called bent spine syndrome. ^{21 ,​ 22 ,​ 23} Camptocormia, derived from the Greek words “camptos” (bent) and “kormos” (trunk), is also known as the bent spine syndrome. ^{21 ,​ 24 ,​ 25} Camptocormia is defined as significant (minimum of 45 degrees) thoracolumbar flexion in the sagittal plane, with almost complete resolution in the supine position. ^{26 ,​ 27} These patients frequently report a gradual, though occasionally subacute, sensation of being “pulled forward” with worsening of posture and pain after prolonged activity. Originally thought to be a psychogenic disorder, camptocormia is now considered to be of idiopathic origin or secondary to neuromuscular disease, including Parkinson’s disease, ALS, polymyositis, inclusion body myositis, muscular dystrophies, myasthenia gravis, and cervical dystonia. An associated condition is proximal myotonic myopathy characterized by progressive painful paraspinal muscle weakness exaggerated by exercise. ²⁸ Other unusual cases of camptocormia have been reported in the literature and observed by these clinicians as well (Fig. 15‑1 a, b). In a 2010 Japanese case report, for example, a patient is illustrated with postherpetic abdominal wall paresis resulting in pseudohernia and 40-degree right convex deformity from T12 to L4. ²⁹

Camptocormia in Parkinson’s disease is caused by myopathy resulting in axial dystonia, ³⁰ resulting in an imbalance of spinal flexion and extension. Camptocormia secondary to neurodegenerative or neuromuscular disorder can be diagnosed by EMG, which reveals weakness of the paravertebral muscles and elevated creatinine kinase levels. Muscle biopsy in patients with Parkinson’s disease reveals disorganized myofibrils with intrafascicular fibrosis and fatty degeneration. ³¹ Magnetic resonance imaging (MRI) findings include early edema and swelling followed by fatty infiltration of paravertebral muscles. ^{32 ,​ 33} Camptocormia occurs in 3 to 17.6% of patients with Parkinson’s disease. ^{24 ,​ 25 ,​ 34 ,​ 35}

15.3.4 Scoliosis

The earliest identification of spinal deformities including scoliosis dates back to Hippocrates, who described spinal curves in his book On Bones and Joints. ^{36 ,​ 37} Traditional definitions of scoliosis summarize the vastly encompassing term as “lateral flexion not relieved by voluntary or passive movement, and lateral curvature of the spine of at least 10° as measured by the Cobb method with evidence of axial vertebral rotation on radiograph.” ³⁸ Scoliosis should be differentiated from the previously described postural deformities including camptocormia, antecollis, and Pisa syndrome as a rigid deformity.

The vertebral column serves to provide support and balance to the human body. Specifically, the spine is the primary means by which the body maintains an upright posture and a horizontal gaze. Dubousset described a theoretical conus within which the whole body maintains an upright posture. His conus ranges from the narrower “cone of economy,” representing minimal exertion, to the “cone of maximum work,” which is the upper limit of energy expenditure. ^{39 ,​ 40} Dubousset visualized a conus of balance for the standing position, in which the feet are located within a zone referred to as the “polygon of sustentation,” and the body, under the influence of muscle function and ligamentous support, can move in a conical fashion without moving the feet. The body adapts to changes in balance in order to regulate the center of gravity over the smallest perimeter possible. ⁴¹ This fundamental tendency toward equilibrium is what drives compensatory changes in the spine as it attempts to adapt to pathological processes either inherent to the spine or external to the spinal column such as neurodegenerative diseases.

Antecollis, camptocormia, and lateral truncal dystonia are postural deformities that can lead to rigid deformities including scoliosis. Specifically, the use of the term scoliosis pertaining to adult patients with neuromuscular diseases such as Parkinson’s disease is restricted to those spinal deformities not related to medical treatment such as L-dopa and not related to any clinical manifestations of the neuromuscular or neurodegenerative disease. Additionally, the direction of the convexity must not be related to the laterality of initial parkinsonian symptoms. ⁴² Scoliosis is more common in patients with Parkinson’s disease (ranging from 43 to 90% ^{42 ,​ 43 ,​ 44} ) compared to an age-matched population (ranging from 6 to 30% ^{45 ,​ 46} ).

While sagittal alignment reflects how the anatomic shape of the spine permits an economical standing position, sagittal balance is a dynamic parameter and corresponds to the ability of the subject to maintain stability of the standing position. Patients with Parkinson’s disease have characteristically poor stability, often presenting with greater oscillations in the standing position and a significantly greater risk of fall. ⁴⁷ In 2005, Sinaki et al demonstrated that patients with hyperkyphosis also present with significant loss of spinal erector muscles (erector spinae) and a compromised gait, leading to trunk shift and a higher risk of falling. ⁴⁸

With regard to spinopelvic malalignment, patients with Parkinson’s disease present with a pattern of flexion of the spine, hips, and knees. Abnormal neuromuscular activation patterns can result in a greater tendency to forward bend, which can lead to global sagittal malalignment, a powerful driver of pain and disability. ⁴⁹ Oh et al evaluated the incidence of sagittal malalignment in a series of patients with Parkinson’s disease and found that 42% had a sagittal vertical axis (SVA) measurement of greater than 50 mm. Furthermore, 51% of patients had spinopelvic mismatch (pelvic incidence minus lumbar lordosis [PI-LL]) greater than 10 degrees, suggesting that the severity of the Parkinson symptoms affects the ability to compensate with pelvic retroversion. ^{50 ,​ 51} Lastly, it is important to note that some patients with Parkinson’s disease may present with de novo or progression of idiopathic scoliosis independent of their neurodegenerative pathology.

An emerging concept with respect to the etiology of spinal pathologies is that there are subclinical changes in the neuromuscular quality of the soft tissues that cause progressive deformity through a mechanism that has not yet been elucidated.

It is not known whether muscle degeneration leads to sagittal imbalance, or whether sagittal malalignment is the premise for muscle degeneration that then drives pain and disability. Further study of the role of “soft tissues” would improve our understanding of compensatory mechanisms (knee flexion, pelvic retroversion, hip hyperextension) that are used to maintain posture in adults with spinal deformity. Future aims to surgically address deformity must take into account this complex pathophysiology in addition to each of these compensatory mechanisms. In summary, understanding the nonbony factors that drive adult neurodegenerative disease will deepen our understanding of adult spinal conditions and optimize treatment strategies.

15.4.1 Nonoperative Treatment

An appropriate history, physical exam, and imaging workup must be obtained for any patient with a neurodegenerative disorder prior to treatment of a spinal deformity. Caution must be taken to rule out other disorders, such as inflammatory myopathies, that are capable of resembling neurodegenerative disorders such as Parkinson’s disease. Moreover, these conditions can similarly be related to the development of spinal deformity, though their responses to treatment differ enormously. This possibility demands the accurate diagnosis prior to intervention. Accordingly, consultation with a neurologist is reasonable to ensure the diagnosis whenever in question and to optimize medical treatment.

Conservative treatment begins with treatment of the primary neurodegenerative condition. While there are no curative treatments for neurodegenerative diseases, various medications have been developed to temporize symptoms and maximize function in these patients. ¹ As consultant physicians, spine specialists must appreciate the risks and benefits of proposed medications with respect to spinal pathologies. For example, L-dopa is effective for the treatment of Parkinson symptoms such as rigidity and akinesia but may exacerbate camptocormia. ^{25 ,​ 26} With respect to treating spinal pathology, nonoperative treatments may include bracing, physical therapy, and injections, with possible adjunctive use of more recently developed technologies such as deep brain stimulation (DBS).

15.4.2 Operative Treatment

Traditionally, the goals of surgical correction of scoliosis involve restoration of coronal and sagittal alignment. ⁵² Specific correction of sagittal malalignment can offer major improvements in quality and functionality in adult spinal deformity patients ^{53 ,​ 54 ,​ 55} ; however, there are many considerations when contemplating surgical treatment in these patients. Moreover, the management of deformity in adult patients with neuromuscular diseases such as cerebral palsy remains challenging with little empiric evidence to support guidelines for operative treatment. ⁵⁶ Despite the absence of studies suggesting optimal spinopelvic parameters in patients with neurodegenerative disease, experience of these clinicians suggests goals similar to those of degenerative scoliosis as follows: pelvic tilt (PT) < 25 deegrees, ⁵⁷ C7–S1 SVA <50 mm, ^{49 ,​ 58} PI-LL < 10 degrees, ^{54 ,​ 57 ,​ 59} and T1 pelvic angle < 20 degrees. ⁶⁰

Related posts:

7 Scoliosis in Cerebral Palsy 9 The Patient with Spinal Cord Injury: Surgical Considerations 8 Surgical Treatment of Spinal Deformity in Myelomeningocele 12 Other Neuromuscular Conditions: Rett Syndrome, Charcot–Marie–Tooth Disease, and Friedreich’s Ataxia 11 Spinal Muscular Atrophy 13 Neurosurgical Causes of Scoliosis

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