Cerebral Palsy

Robert M. Kay, MD

John M. (Jack) Flynn, MD

Jon R. Davids, MD¹

Guru:

General Considerations

Cerebral palsy (CP) results from damage to the immature brain, typically before age 2 years. Despite medical advances over the past several decades, the incidence of CP has not declined, and CP remains the most common motor disease of childhood. Currently, CP is estimated to affect 1 in every 300 to 400 children in the United States, with nearly 1 million affected individuals in the United States and 17 million worldwide. As a result of increased life expectancy in people with CP, there are now more affected adults with CP than children.

Historically, risk factors cited for CP have included premature birth, multiple gestation (e.g., twins, triplets, etc.), low birth weight, and need for oxygen following birth. In fact, the vast majority of children with CP do not have any known risk factors for having CP. Genetic causes of conditions presenting like CP are becoming increasingly recognized.

CP is now considered to be a group of disorders characterized by a static brain lesion which occurs before age 2 years. Although CP is typically thought of as a motor disorder, children with CP often have limitations in cognition, sensation, proprioception, and thermoregulation, and many affected individuals have pulmonary, gastrointestinal, genitourinary problems, and/or seizure disorders.

One of the important things to understand about people with CP is that they often have very different functional abilities in different domains. For example, some people with CP have severe motor involvement and are completely dependent for activities of daily living (ADLs) but have very good intellectual capacity, while others may have minimal motor limitation, but be severely cognitively impaired.

The brain lesion itself in CP is nonprogressive, though the peripheral manifestations (stiffness, contractures, and bone deformity) often progress with time. If there does seem to be progression of the neurologic problems in a child with CP, you should consult a neurologist, developmental pediatrician and/or geneticist to confirm the proper diagnosis, and whether or not other issues may have arisen (such as onset or progression hydrocephalus).

Classification

There are numerous ways to classify people with CP.¹ Some of the common classification methods include systems based on geographic distribution of the CP, type of motor involvement, and functional level. By sorting out and categorizing these children, you can stay out of trouble by expecting certain problems more frequently in particular groups.

GEOGRAPHIC CLASSIFICATION

Over time, the most common classification scheme has been based on geographic distribution of CP. This classification has categorized affected people as having hemiplegia (one side of the body involved), diplegia (both legs involved, with relative sparing of the arms), triplegia (both legs and one arm involved, with relative sparing of the other arm), quadriplegia (all four extremities involved), or tetraplegia (all four extremities plus bulbar involvement). Because there are gray areas in this classification scheme (e.g., essentially all children with “diplegia” have some degree of upper extremity involvement as well), health care providers in Europe often classify people as having unilateral or bilateral CP.

Because there are some useful distinctions when using a geographic classification of involvement (as discussed later), we believe there remains some value in such a classification of involvement for those with CP. Classifying the type of CP—diplegic, quadriplegic, hemiplegic, spastic, athetoid, etc.—can be difficult in some children but is helpful overall.

MOTOR INVOLVEMENT CLASSIFICATION

A common way to categorize those with CP is by the type of motor involvement they have. Those with spasticity (also sometimes referred to as having “spastic cerebral palsy”) have increased tone and stiffness in the muscles with an exaggerated stretch reflex (and resultant increase in their reflexes, also known as “hyperreflexia”). Children with spastic CP are often the ones whom we can help most as orthopaedic surgeons. The opposite of spastic CP is “hypotonic” (low-tone) CP. These children have low tone and decreased stretch reflexes but have many of the same nonoperative needs (though fewer operative ones) than those with spastic CP.

Dystonia has become increasingly recognized as a significant problem in patients with CP. Dystonia is abnormal muscle tone in muscle(s), which typically results in repetitive posturing by the affected person. Although the particular muscles involved and the particular postures that result vary among affected individuals, the affected muscles and postures are very repetitive and consistent for a given person. For example, for one person, the dystonia may involve repetitive foot and ankle posturing into specific positions, while, in another, the posturing will affect different extremities and muscle groups. Dystonia often is not evident in young children but becomes more evident and problematic with time, particularly as children near and pass through adolescence.

Many children with CP have mixed patterns of CP that involve a combination of the aforementioned types of motor involvement. In young children, hypotonia of the trunk (“truncal hypotonia”) is often seen in conjunction with spasticity of the extremities. Dystonia is often combined with spastic and/or hypotonic CP.

FUNCTIONAL CLASSIFICATION SYSTEMS

The most widely used classification system currently used is the Gross Motor Functional Classification System (GMFCS). The GMFCS has become the preferred classification system for communication among those treating children with CP.¹,²,³ There are five GMFCS levels. GMFCS I and II children both walk in the community without ambulatory aids, with the difference being that level I children do not use handrails while climbing stairs (level II children do) and GMFCS I children do well on all surfaces and level II children may have difficulty on uneven surfaces. Level III children are community ambulators with ambulatory aids (crutches or walkers). Level IV children do limited walking in therapy and/or other therapeutic settings (e.g., school, particularly with adaptive physical education). Level V children do not have head and neck control and are dependent for mobility; however, they may be placed upright in fully supportive standers.

Other classification systems are used, though less commonly by orthopaedic surgeons. These include the Manual Activity Classification System (MACS), which rates children on an ordinal rating system with five levels. The extremes include MACS I (a child who handles objects essentially without limitation) and MACS V children who do not handle objects. Similarly, the Communication Functional Classification System (CFCS) is a five-level system, with level I children easily and effectively sending and receiving messages in the majority of settings with the majority of people and level V children rarely effectively communicating with anyone.

Evaluation

The first time a patient with CP comes into your office can seem overwhelming. Unlike the simple assessment of an otherwise-healthy child with a buckle fracture of the radius, adequately addressing the myriad issues common in children with CP can make this task seem insurmountable.

As with other complex processes, the key is to simplify by coming up with a problem list and a treatment plan to address these problems. You can sometimes even start the process before entering the patient’s room. For instance, you may be able to observe how the child gets to the examining room. Do they walk or use a manual or power wheelchair? Who is with the child and how does the child interact with those accompanying them? If the child walks, take this opportunity as they walk to the room to observe their gait, since this may well be more representative than the “doctor’s walk” the child will do for you after you have met and they know you are watching (and possibly considering bracing or surgery).

When addressing the child and family, ask about their main concerns. Many of the assumptions we may have as health care providers are very different from the priorities for the patient and family. Making sure to find out their needs—and making sure to do our best to meet those needs—is critical to patient and family satisfaction. NEWSFLASH! Once the child is in the room, make sure to talk to them and not just those accompanying them. In addition to being humane and considerate, asking questions directly to the child will help you assess their cognitive abilities, including expressive and receptive language.

Although the entire health care team caring for a child with CP should be working from a comprehensive history and physical examination, the orthopaedic surgeon should specifically be attuned to a few very important pieces of information. Birth history, including any problems during the pregnancy and delivery, is sought. Motor and cognitive milestones are assessed, and it is often helpful to ask the parent(s) how these milestones compared to their other children. Asking when they first noted that there was a problem is useful. You should ask about when the child demonstrated “handedness.” NEWSFLASH! Children should use both hands essentially symmetrically until at least 12 months old. A child who shows hand dominance before age 1 year has pathology affecting the nondominant arm; commonly, this is due to hemiplegic (or unilateral) CP.

Physical examination requires a thorough assessment of the entire child. Patience is key as the child is often anxious and/or fearful, either of which will typically increase spasticity and make examination more challenging. Tone is assessed in the trunk, spine, and extremities. Any dystonia should be noted. The child is asked to perform gross and fine motor tasks, as possible, based on both cognitive and motor function. All extremities are taken through a range of motion to assess for any contractures as well. Bilateral examination is critical for assessing symmetry. Subtle findings such as unilateral increased tone of the forearm pronators may be one of the only upper extremity findings in early hemiplegic (unilateral) CP. Watching the child handle objects while you are talking to him and the parents can be very telling.

There are several pitfalls to avoid while examining a child with CP. Hip abduction should be tested with the hips and knees extended. Patience is essential. If the examination is done hastily, the child’s muscles will tense up and you will probably be testing spasticity more than you are testing the actual joint range of motion. When testing popliteal angles, the opposite hip must remain fully extended. It is a rookie error to allow the opposite hip to flex, which relaxes the hamstrings and leads to underestimation of the popliteal angle. Test ankle dorsiflexion with
the knee flexed and extended (Silfverskiöld test), and be sure that the hindfoot is inverted, so that dorsiflexion through the midfoot does not fool you into overestimating ankle dorsiflexion and underestimating the extent of the equinus contracture (Fig. 16-1). It is best to first check dorsiflexion with the hip and knee flexed, to get the child into a flexor pattern and increase static ankle dorsiflexion. For quadriplegic children with severe CP, if you get them in the sitting position to examine, the spine you will be able to evaluate how their spine is positioned when upright. Having the child lie on his side will allow you to check how flexible the spine is. True (rather than “postural”) scoliosis is heralded by rotational deformity of the trunk. Postural curves, and or early nonstructural curves, will not have a fixed rotatory component.

Figure 16-1 A: The incorrect way to check ankle dorsiflexion, because the examiner allowed the subtalar joint to go into eversion; this allows dorsiflexion to occur through the midfoot and may fool the examiner into thinking that there is sufficient ankle dorsiflexion. B: The correct technique, using hindfoot inversion, reveals that there actually is an ankle equinus contracture in this child. (Used with permission of the Children’s Orthopaedic Center, Los Angeles.)

Depending on upper extremity function, the child can be presented with objects to grasp, asked to transfer from hand to hand, and may be asked to do finger tapping, rapid alternating movements, and/or bimanual activities (donning and doffing socks or shoes, buttoning buttons, zipping up zippers, etc.). In younger children, simply observing them handling toys and/or other familiar objects may be all you can accomplish.

In addition to tone and range of motion assessment in the lower extremities, standing, transferring, and/or gait are assessed, depending on the child’s functional level. Whenever possible, it is useful to see a child in and out of her leg braces. If the child needs handheld support or ambulatory aids, gait can be assessed with such assistance and/or aids.

Evaluating the gait of an ambulatory child with CP can be overwhelming to the less experienced. A systematic method for examining gait is needed. It is important to observe the child’s gait from both the front and the side to assess the various joints, body segments, and planes of motion. By taking a stepwise observation strategy with each walk down the hall, you can get a better sense of the problems.

Watch the child walk with and without braces, so you can assess the optimal brace for that particular child. Look at the shoes of a walking child to assess whether the toes are wearing out. This can be an indicator of foot clearance problems, which can be seen with ankle equinus and/or a stiff knee in swing phase (which is often associated with rectus spasticity).

Of course, there is no specific diagnostic test to establish the diagnosis of CP. Many neurologists obtain a brain MRI, looking for characteristic abnormalities. Parents will sometimes ask the orthopaedist to order the brain MRI or to review it with them. The potential value of the MRI must be weighed against potential risks, including the need for sedation in young children. In most cases, the need for an MRI can be determined by the neurologist. One case in which an MRI should be ordered by the orthopaedist is in a child with hemiplegia and no risk factors or history that provides an adequate reason for the hemiplegia.

THE GURU SAYS…

All parents of very young children receiving the diagnosis of CP want to know if their child will ever walk. I counsel them that achieving head control by 9 months of age, and sitting independently by 2 years, predicts that functional (GMFCS III or better) ambulation will be attained by around 7 years of age. I never say anything that completely takes away a parent’s hope for their child. When delivering difficult news, I share that statistics are for populations, not for individuals, and while the prognostic measures are usually correct, I have seen children who defy the statistics (e.g., in the case of ambulat ion achieve walking ability between 7 and 10 years of age). Hope is a powerful motivator and should never be completely extinguished by the physician…acceptance should come from the parents and then be recognized with compassion by the physician.

JON DAVIDS

Depending on your comfort level, you may want to work together with the neurologist when diagnosing a child with CP, since the diagnosis of CP can carry profound implications. Many parental emotions and fears are attached to the words “cerebral palsy,” so it is extremely important to contextualize this diagnosis. Many parents have a misconception that every child with CP is severely involved, such as those who are at GMFCS IV and V. You need to explain that children with CP have very different functional abilities, and that they typically gain motor milestones for many years (usually until at least 6-8 years old). Parents of a young child who already stands or walks, for instance, should be informed that such progress is expected to continue. Explain to the parents that although CP is not a progressive neurologic problem, the musculoskeletal manifestations of CP can change with time and growth. It is important to understand that some degree of gross motor functional deterioration does often occur in adolescence in children at GMFCS III, IV, and V levels, though conveying such information is not a good idea on the visit during which the diagnosis is first made. Such a conversation is better deferred until there is a closer bond between physician, patient, and family, and the child’s prognosis becomes clearer.

Although a CP team approach is not available to all orthopaedists, one of the best ways to stay out of trouble is to work with other health care professionals knowledgeable about children with CP. If your institution has such specialists (pediatric neurologists, neurosurgeons, developmental paediatricians, physiatrists, and physical, occupational, and speech therapists), it is best to involve others whose assessments can help maximize outcomes and quality of life.

Surgery to Improve Walking

If you plan to do surgery on a child with CP, there are some important things to consider to stay out of trouble. Mercer Rang taught us that one of the keys to staying out of trouble when caring for children with CP is to avoid the “birthday syndrome,” in which a different muscle group is released each year, leading to extensive multiple surgeries. Dr. Rang also taught us that regarding the outcomes of surgery in children with CP, “The decision is more important than the incision.” Today, most orthopaedic surgeons know the importance of correcting problems at multiple levels simultaneously in children with CP, rather than leaving some
deformities uncorrected. Single-event multilevel surgery (SEMLS), in which multilevel bone and soft-tissue surgeries are performed simultaneously to improve gait and function, has been the standard of care in these children for many years.

Typically, the best candidate for SEMLS surgery is a child who meets the following criteria: (1) they are aged 6 to 10 years, (2) their gross motor function has plateaued for at least 6 months, and (3) there are no nonsurgical ways to address the musculoskeletal problems interfering with gait and function. Evaluation using computerized gait analysis (CGA) facilitates this assessment, particularly in children with complex walking patterns.⁴,⁵ In the absence of CGA, the child should be examined on at least a few occasions prior to surgery, and video taken from the front and side of the child walking can greatly enhance decision-making preoperatively. There are many readily available and inexpensive software apps available for mobile phones which allow the video to be slowed down and even freeze-framed and allow the user to measure joint angles as part of the gait assessment.

To stay out of trouble, make certain that the patient and family are committed to the postoperative therapy. A “great” surgery without quality therapy will yield disappointing results. After extensive surgery, the patients typically need quality physical therapy at least two to three times weekly for 2 to 3 months. If the patient and family are not able to commit to the therapy, surgery should be deferred until a time when they can make the commitment. NEWSFLASH! Even under optimal circumstances, it generally takes a child 4 to 6 months to return to baseline functional status after SEMLS, and functional improvement often occurs for 2 years after surgery. In a teenager with CP, return to functional baseline may take up to a year. These older and bigger children are slower to heal and have a much less favorable strength-to-weight ratio. You will do everyone a favor by being up front about these issues before surgery.

Overlengthening of tendons can be a major source of trouble. Though most commonly thought of as a problem at the level of the ankle, overlengthening can be problematic at other levels as well. Overlengthening at the hip (especially if combined with obturator neurectomy) can lead to hip hyperabduction. Overlengthening of the hamstrings often leads to recurvatum and/or a stiff knee gait. Overlengthened heel cords result in calcaneal crouch.

Children with dystonia present significant challenges to the surgeon. Soft-tissue procedures, such as tendon lengthenings and transfers, have unpredictable results in children with dystonia and should be avoided whenever possible. Well-planned bone surgery can be of benefit in children with dystonia.

Casts can cause significant problems in children with CP, and their use is minimized when possible. When casts are used, the surgeon should exercise great care in cast application. Foam padding has been shown to be a low-cost way to decrease skin complications following lower extremity postoperative casting in children with CP.⁶

To keep children with CP comfortable after surgery, diazepam is used routinely to help with the muscle spasms. Narcotics may be helpful at first but are not as valuable as the antispasticity medicines perioperatively.

Specific Challenges by Anatomic Area

SPINE DEFORMITY

Spine deformity is one of the most common complaints of patients and families in children with CP. The rate of significant scoliosis is directly related to GMFCS level, with very low rates (similar to the overall population) in GMFCS I and II children, and significant scoliosis in the majority of GMFCS V children.

Early on, there is typically not a fixed deformity. In children whose deformity is due to trunk weakness and lack of postural control, the spine will be noted to curve when the child is upright but to be straight when the child is supine or lying on his side. Lying the child on his side will mitigate the effects of gravity on the spine and allow an easy assessment of whether there is a fixed spinal deformity.

When there is a fixed spinal deformity, there will be thoracic and/or lumbar “humps” due to the rotational component of the deformity. The development of a rotatory deformity is the typical indication for spine radiographs. The radiographic technique should be consistent from visit to visit (e.g., sitting or supine) to allow for accurate assessment of any deformity progression. Sitting X-rays have the benefit of assessing the spinal deformity when the child is upright during daily activities. It will uniformly look worse than a supine film. The supine film has the advantage of eliminating the effects of gravity and is a more accurate reflection of fixed deformity.

Treatment

Bracing

Bracing (with a thoracolumbosacral orthosis or TLSO) is commonly used in children with CP and spinal deformity. It is important to recognize that a TLSO has not been proven to significantly change the natural history of spinal deformity in children with CP. However, use of a TLSO can enhance the quality of life of the child and family, by facilitating sitting (especially when out of the wheelchair). By facilitating sitting, the TLSO can often free up the child’s hands for use.

When a TLSO is used in a child with CP, it differs from that used with idiopathic scoliosis. The TLSO for a child with CP should be a softer, “flex foam” type of TLSO to allow for appropriate postural support. Children with CP rarely tolerate a rigid TLSO, and such rigid bracing can lead to pressure sores, particularly in those with limited ability to communicate.

Occasionally, for children with significant scoliosis and in whom the patient and family have decided against surgery, the spine deformity can be addressed with a custom molded back for the wheelchair. Though this does nothing to correct the deformity, it can facilitate positioning, and the custom mold essentially braces the child when she is in her wheelchair.

Surgery

The decision for spine fusion surgery is a big decision for the patient and family. These are large surgeries with a significantly higher risk profile than for idiopathic scoliosis. However, there is a high level of patient and caregiver satisfaction after successful spine fusion in these patients. Jain et al. have recently reported significant improvement in quality of life in children with CP following spine fusion in patients with CP.⁷ It is important to assure that the family is ready for a journey that can include many setbacks—prolonged hospital stay, wound infection, changes to the seating system (ordering new a wheelchair for child with a new shape can take many months in some areas). It is wise not to book surgery the first time the curve magnitude crosses 50°. Instead, share the risks and benefits, then send the family away thinking, and perhaps getting any necessary preoperative medical consults. See them back in 4 to 6 months and make a plan. Be careful not to go more than about 6 to 9 months—the deformities can progress rapidly when the curve is more than 60° and the spine is collapsing in these children with softer vertebrae.

Waiting until curves get much larger (and stiffer) often results in longer, more complicated surgeries, greater blood loss, longer hospital stays, and a larger residual curve.

Figure 16-2 Spine deformity correction in CP.

Spine fusions are typically very long (upper T-spine to pelvis) for children with CP spine deformities (Fig. 16-2). Fusion to the pelvis is controversial. If the pelvis can be spared, complications such as pelvic pain, implant loosening, and surgical site infection are lower. Competent therapists note that seating is much easier if the child is not “a single cement block,” as they say; having a jog of motion at the lumbosacral junction permits more comfortable seating. However, it is imperative that the technical execution for fusion to L5 be excellent. The pelvis at L5 must be leveled with intraoperative traction before the start of surgery. L3, L4, and L5 must have bilateral pedicle screw fixation, and each must be leveled. In general, the best deformities for fusion to L5 are the more flexible curves with a more cephalad apex. Unfortunately, if the fusion to L5 at the initial surgery does not level the three end vertebrae and revision surgery is required, the surgical times can be long and the blood loss similar to a primary long fusion to the pelvis.⁸ So, to stay out of trouble, choose candidates for fusion to L5 wisely, and level those three lower vertebrae with bilateral screws. If you can, you are doing the child
a favor for the rest of their sitting life. If it is not possible due to curve rigidity, magnitude, or caudal apex, then fuse to the pelvis.

Because of the traditional high rates of infection following posterior spinal fusion in this patient population, there have been recent trends toward more aggressive preoperative preparation, use of broad-spectrum antibiotics perioperatively, intraoperative wound lavage, and the use of impermeable dressings postoperatively (to avoid fecal contamination of the wound in these patients, who often lack bowel control). Such measures have markedly diminished the infection rate in this population.

HIP DISPLACEMENT

Hip subluxation is very common in children with CP. Previous studies have been all over the map as far as the risk of subluxation, ranging from less than 10% to more than 70%. Traditionally, the risk for hip subluxation was stratified by the geographic distribution of a child’s CP, with low risk in those with hemiplegia, moderate in diplegia, and high in quadriplegia.

The GMFCS classification is the best way to stratify the risk of hip subluxation in CP. Soo et al. reported hip subluxation in 35% of their cohort of children with CP and a linear relationship between the risk of hip subluxation in children with CP, including a 0% risk in their GMFCS I patients and 90% in their GMFCS V children.⁹ Previous authors have also shown that increased hip displacement is associated with a lower quality of life in children with CP.¹⁰

Since hip subluxation can only be detected definitively with radiographic evaluation, it is imperative that all children with CP undergo radiographic hip screening. NEWSFLASH! There are different guidelines worldwide, but there is consensus that all children with CP need hip screening, typically beginning by age 2 to 3 years. The frequency of screening thereafter varies depending on GMFCS level, previous radiographs (i.e., presence of subluxation and/or progressive hip migration), and physical examination. The frequency of screening X-rays should be greatest in children with the most severe involvement (GMFCS IV and V) and least frequent in those with mild involvement (GMFCS I and II). One group of highly functional children (GMFCS I or II) who have significant risk of later hip subluxation or dislocation are Winters and Gage type IV hemiplegics (who walk with a flexed, internally rotated hip, and flexed knee).¹¹ Remember that a screening hip radiograph can look relatively normal in a child with CP but can progress to complete dislocation (Fig. 16-3).

It is not unusual for the parent of a school-age child with CP to present to the orthopaedist’s office complaining that the child has hip pain. To stay out of trouble, understand that there are many different things that cause pain besides
the hip joint itself. Even with a radiograph that shows some hip subluxation, be certain that there is not an abdominal source for the pain. Reflux, constipation, hernias, and other conditions can mimic the pain of spastic hip disease. Also, spastic hip adductors may be the real source of pain in a younger child. It is very unlikely to have actual joint pain in a younger child, even with severe subluxation.

Figure 16-3 A: A screening X-ray in this patient with CP (GMFCS IV) at age 4 y shows well-reduced hips and good acetabular morphology. B: Unfortunately, he did not undergo routine hip screening, and at age 17 y, he had windswept hips with a dislocated, misshapen, painful, and unreconstructible right hip. (Used with permission of the Children’s Orthopaedic Center, Los Angeles.)

On physical examination, there are three main findings to look for that are suggestive of hip subluxation and/or dislocation. The first is the Galeazzi sign, in which the hips are adducted and flexed to 90°; a positive Galeazzi (knee heights are different) is suggestive of asymmetric hip subluxation and/or dislocation. The second is the degree of hip abduction (typically tested in extension). Asymmetry between the hips, loss of abduction since the previous visit, and/or abduction <20° in extension are suggestive of the possibility of hip subluxation. Finally, posterior prominence of the femoral head is typically assessed with the hips and knees flexed to 90° as the examiner axially loads the knees (pushing posteriorly on the knees) and palpates for the femoral heads in the buttocks.

Beware of anterior hip dislocations. Although they make up <5% of hip subluxations and dislocations in children with CP, they can be more difficult to diagnose.¹² To stay out of trouble, understand that the radiographs in children with an anterior hip dislocation often shows little, if any, lateral hip displacement. These children do not have the classic hip flexion adduction posture. Instead, they are usually in figure 4 (or “frog”) position with the hips extended, abducted, and externally rotated. If you feel an anterior prominence in the groin and see this figure 4 position, the diagnosis is an anterior dislocation. Though uncommon, some children with significant posterior subluxation will not show lateral translation either, and advanced imaging may be needed to assess their anatomy (Fig. 16-4).

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