Acute flaccid myelitis: Rehabilitation challenges and outcomes in a pediatric cohort

Abstract

PURPOSE:

To describe one institution’s experience in the rehabilitation of children with acute flaccid myelitis (AFM). This study reviews the medical and rehabilitative course and functional outcomes of a cohort of children who underwent Activity Based Restorative Therapy (ABRT) at a single center.

METHODS:

Children with AFM presenting for rehabilitation between March 2005 and January 2017 were identified and a retrospective chart review was conducted. Changes in medical and functional status were assessed using multiple standardized instruments, as well as a chart review of medical progress.

RESULTS:

Thirty-one children with AFM treated at our institution in the study time period were identified. Of these, seventeen received inpatient treatment, and fourteen received solely outpatient interventions. Their medical and functional outcomes are described with use of standardized measures when available.

CONCLUSIONS:

Children with flaccid paralysis due to AFM undergoing structured, comprehensive rehabilitation interventions, even when these are initiated long after paralysis onset, can make significant neurologic and functional gains. Recovery of function and prevention of comorbidities are the main therapeutic targets for interventions in this population.

Keywords

Acute flaccid myelitis spinal cord injury paralysis rehabilitation functional outcomes

1. Background

Historically, the most devastating and well known cause of acute flaccid paralysis was poliovirus with over 15,000 cases reported annually during the peak of the polio epidemic [1]. In the 1950s and 1960s, the introduction and widespread use of polio vaccines resulted in the number of cases of polio plummeting. By 1978, polio was considered eradicated in the United States. Internationally, The Polio Eradication & Endgame Strategic Plan 2013–2018 of the World Health Organization (WHO) continues steadily eradicating the remaining hotspots of polio in the developing world including Nigeria, Afghanistan, and Pakistan [2, 3]. Active epidemiological surveillance for acute flaccid paralysis was discontinued in the United States with the eradication of polio. Sporadic cases of acute flaccid paralysis caused by a variety of other enteroviruses including Coxsackie B3/B4, West Nile Virus, and Enterovirus D-71 (EV D-71) continued to be reported in the literature [4, 5, 6, 7].

In 2012, an increasing number of cases of flaccid paralysis were reported in the United States with a cluster of patients reported in California, some in association with Enterovirus D-68 (EV D-68). In the fall of 2014, the United States experienced a multi-state outbreak of EV D-68, with over 1150 cases reported [8]. Most patients had respiratory symptoms of cough, runny nose, sneezing, myalgia, and bronchospasm. Concurrently, reports of children with acute flaccid paralysis began to increase [9, 10, 11, 12, 13].

As a result of these reports, a case definition for a new entity, Acute Flaccid Myelitis (AFM) was developed by the CDC to accurately identify cases of AFM and to assure the differentiation of AFM from other causes of paralysis in children. As of August 1, 2015, a confirmed case required acute onset of focal limb weakness and an MRI showing a spinal cord lesion largely restricted to gray matter and spanning one or more spinal segments. A probable case required acute onset of focal limb weakness and CSF with pleocytosis. In addition, the 2014 case definition, which had been limited to those under 21 years old, was expanded in 2015 to include all ages [14]. As a result of increased awareness and surveillance, a significant increase in the diagnosis of AFM in children has been seen, along with an increased number of those in need of spinal cord injury (SCI) rehabilitation following their acute illness.

Due to the recent recognition of AFM, there is minimal data available in the literature predicting outcomes and identifying optimal rehabilitative interventions. This descriptive study will present the medical and rehabilitative course and functional outcomes of a cohort of children with flaccid paralysis who underwent Activity Based Restorative Therapy (ABRT) in a single center between March 2005 and January 2017.

2. Methods

The study was approved by the Kennedy Krieger Institute and the Johns Hopkins Institutional Review Boards (IRBs) for human subjects research. This was a retrospective medical records review of all patients aged 0–21 years presenting for outpatient and inpatient intensive spinal cord injury (SCI) rehabilitation from March 15, 2005 through January 30, 2017 who met the 2015 CDC confirmed case definition for AFM. Information reviewed included antecedent factors; description of the acute illness; physical and neurologic examination including bowel, bladder, respiratory and cardiovascular status; imaging and laboratory workup; and medical and functional status at the time of admission to and discharge from rehabilitation, including complications during treatment.

All patients participated in an intensive Activity Based Restorative Therapy (ABRT) program to promote functional gains and neural restoration. Out of the 31 children, 17 participated in an intensive inpatient therapy program involving: two to three hours of physical therapy (PT), one to two hours of occupational therapy (OT), and up to an hour of speech therapy (if needed) each day, five days a week with approximately two hours of therapy on the weekend. Other consult services were available as needed during their admission: social work, behavioral psychology, neuropsychology, child life, recreational therapy, nutrition, and respiratory therapy. A total of 14 patients began their rehabilitation at our institution in an intensive outpatient therapy program which included PT and OT as appropriate. The total number of visits was dependent on the patients’ needs and geographical location of their home.

The goal of ABRT is to facilitate near-normal movement and achieve neurodevelopmental milestones by providing input both above and below the level of injury [15]. ABRT consists of five primary components including: functional electrical stimulation (FES) [16], weight bearing, locomotor training [17, 18], task-specific practice [19], and massed practice [20]. Patterns of paralysis associated with AFM include flaccid paralysis which is suggestive of lower motor neuron dysfunction and greater proximal involvement. However, many of these patients present with intact sensation, making FES treatments challenging. The most successful applications of FES include a low frequency and long pulse width, allowing sluggish motor units time to respond with greater refractory periods [21]. Patients completed weight bearing daily through lower and upper limbs as appropriate for their presentation. Locomotor training was completed three to five times a week when applicable, including treadmill and over-ground retraining using a body weight-supported system. Task-specific practice and massed practice were completed daily with the goal of completing as many repetitions as possible for neurological and daily function restoration.

All children in this cohort also received interventions including but not limited to: whole body/focused vibration therapy, Kinesio Taping ${}^{\@setsize{\scriptsize}{8pt}{\viipt}{\@viipt}\textregistered}$ , aquatic therapy, and seating and positioning evaluations. These interventions were aimed to facilitate development, minimize chronic complications, increase independence, and help patients achieve their maximum potential to fully integrate back into all of their roles in society. Ten of the children underwent nerve transfers.

Functional status was assessed using standardized tools including Spinal Cord Injury Measure (SCIM), Physical Ability and Mobility Scale (PAMS), and the Functional Independence Measure for Children (WeeFIM ${}^{\@setsize{\scriptsize}{8pt}{\viipt}{\@viipt}\textregistered}$ ). Rehabilitation therapy-specific tools included assessment of mobility and transfers, balance, ambulation, activities of daily living (ADLs), hand function (strength and skills), durable medical equipment, and orthotic use.

3. Results

3.1 Clinical description of cohort

Between March 15, 2005 and January 30th, 2017, 31 children with AFM (17 males and 14 females) were seen at our facility for intensive SCI rehabilitation. Ages ranged from as young as 7 months to 16 years. Most ( $n=$ 18) were admitted from home and almost half ( $n=$ 14) were diagnosed retrospectively using the CDC 2015 revised criteria (see Table 1). Ten of these children were from the 2014 outbreak, 7 from the 2016 outbreak, and 14 had onset of illness prior to 2014; in this cohort, the earliest onset of paralysis was recorded as occurring in October 2006, with the child starting ABRT 5.5 years post onset (longest time between paralysis onset and ABRT start). In the whole cohort, time to start of ABRT ranged from 0.5 to 77 months.

Table 1
Cohort demographics

	Demographic	Number (%)
Total number	31
Age range	7 months – 16 years
Sex	Female	14 (45.2%)
	Male	17 (54.7%)
Year of diagnosis
	Prior to 2014	14 (45.1%)
	2014	10 (32.3%)
	2016	7 (22.6%)
Referral source
	Acute care hospital	10 (32.3%)
	Rehabilitation facility	3 (9.7%)
	Admitted from home	18 (58%)
Initial rehabilitation location
	Outpatient	14 (45.2%)
	Inpatient	17 (54.8%)

In terms of presenting complaints for the prodromal illness, most had fever ( $n=$ 29) and upper respiratory infection ( $n=$ 17). A small number ( $n=$ 3) presented with gastrointestinal illness. Neurologically, 26 presented initially with monoplegia, with 15 progressing to more fulminant neurological involvement; five eventually developed complete respiratory failure as a result of their paralysis. Of those presenting with monoplegia, 11 involved a lower limb and 15 involved an upper limb. In 24 of the cases, a lumbar puncture was performed as part of the diagnostic workup. Pleocytosis was noted in 19 cases, with lymphocytic predominance in seven and an elevated protein in eight (see Table 2).

Table 2

Clinical presentation and initial evaluation

Presenting complaint/finding	Numbers ( $N=$ 31)
Symptom
Fever	29
URI	17
Respiratory failure	5
Gastrointestinal symptoms	3
Monoplegia	26 (15 progressed to involve more limbs)	15 upper extremity
		11 lower extremity
Lumbar puncture (24 done)
Pleocytosis	19
Lymphocytosis	7
Elevated protein	8
Positive cultures	0
MRI	31 with anterior horn involvement; 5 also
Spine	had polyradicular extensions, and 5 with cervicomedullary junction involvement
EMG (7 done)	All showed anterior horn involvement; abnormal or unobtainable late response F waves and H reflex; and normal sensory conduction.
Infectious agents found
EV D-68	5
Rhinovirus	2
Mycoplasma, EBV, HHV6	1 each

Central nervous system imaging of both brain and spinal cord was performed in all patients. On spinal cord MRI, all patients showed anterior horn involvement, five of them demonstrated additional polyradicular extension, and six demonstrated nonspecific white matter tract involvement.

All patients had extensive evaluation to find the etiology of the AFM. This included testing for infectious causes such as West Nile virus, Western Equine virus, St. Louis encephalitis virus, Herpes Simplex virus, Coxsackie virus, Lyme, syphilis, and Bartonella. Enterovirus D-68 was confirmed in four cases (nasopharyngeal testing), while two patients tested positive for rhinovirus, one for Human Herpesvirus 6, and one for Mycoplasma. Testing for various autoimmune etiologies including lupus, neuromyelitis optica, paraneoplastic syndromes, hereditary neuropathies, endocrine dysfunctions (i.e., thyroid) and demyelinating diseases (i.e., oligoclonal bands, myelin basic protein) were negative.

EMG/nerve conduction studies were documented in seven of the 31 individuals in the cohort; they showed a predominance of anterior horn involvement, with abnormal or unobtainable late response F waves and H reflex. All showed normal sensory conduction.

Acute treatment was varied and reflected the diagnostic challenge which was present with the early outbreaks in 2014. All patients in our cohort were given high dose corticosteroids ( $n=$ 31) with unclear effect on symptoms. Nineteen had intravenous immunoglobulin (IVIG) and plasmapheresis was used in ten patients. Due to severity of illness, two patients required extracorporeal membrane oxygenation (ECMO). Fluoxetine was trialed in four patients due to reports of utility in motor recovery in stroke patients, as well as its in vitro inhibition of enterovirus replication [22].

Sensation was noted to be intact in almost all patients (28/31) both at admission and discharge. The three patients deemed to have impaired sensation were under four years of age, so accurate assessment of sensory function was unreliable and difficult. However, they were felt to have decreased reaction to pin prick assessment versus expected.

Pain was reported in 19/31 patients at admission and 12/31 at discharge. In general, the nature of pain at admission was reported as neuropathic – thus, 11/19 patients were treated with gabapentin initially – whereas the pain at discharge was reported as more neuromuscular in nature. In the 14 patients that were evaluated as outpatients only, there were no reports of pain at the time of their clinic evaluation.

Six out of the 31 children were less than four years of age, making accurate assessment of bowel and bladder continence difficult. Of the remaining 25, on admission 10 were incontinent of bowel and 8 were incontinent of bladder. By discharge, only one child continued to have bowel incontinence and none had bladder incontinence.

About a third of the children were found to have joint range of motion limitations due to muscle contracture in the affected limb(s) (10/31) or scoliosis (11/31). Both limb contractures and scoliosis were documented in four patients.

No significant cognitive impairments were identified in any of the children included in this cohort.

3.2 Respiratory outcomes

There were 17 unique inpatients in the relevant time period, with two admitted twice each, for a total of 19 admissions. On admission, seven of those were on mechanical ventilators, nine required no ventilatory support, and the remaining three were mixed (on CPAP or BiPAP, or on vent at night only). Of the ten patients who admitted with any degree of support, eight were able to decrease that support (either to lower ventilator settings, PAP only during the day, or weaned off ventilator completely), while two discharged at the same degree of respiratory support as on admission (see Table 3).

Table 3
Respiratory support requirements, admission vs. discharge

Type of respiratory support	# at admission	# at discharge
Ventilator 24 hours/day	7	4 (3 of these with decreased settings)
CPAP/BiPAP 24 hours/day	2	0
Vent at night/PAP during/day	1	1
Vent at night/no support/day	0	2
PAP at night/no support/day	0	1
No support for 24 hours/day	9	11
Total number with decreased respiratory		8 (80% of those with any respiratory
support by time of discharge:		support at time of admission)

Table 4

Outcome measure scores: inpatient admission to discharge

	Admission		Discharge
	M	SD	M	SD	$t$ -test	$p$ -value
SCIM ( $n=$ 11)	24.6	18.5	49.5	29.1	$-$ 3.10 ${}^{*}$	0.007
PAMS ( $n=$ 17)	44.3	21.8	65.2	21.5	$-$ 5.07 ${}^{**}$	$<$ 0.001
WeeFIM ${}^{\@setsize{\scriptsize}{8pt}{\viipt}{\@viipt}\textregistered}$ Self-Care DQ ( $n=$ 13)	42.7	25.7	67.5	26.1	$-$ 5.48 ${}^{**}$	$<$ 0.001
WeeFIM ${}^{\@setsize{\scriptsize}{8pt}{\viipt}{\@viipt}\textregistered}$ Mobility DQ ( $n=$ 13)	37.1	27.9	61.7	21.9	$-$ 4.12 ${}^{**}$	0.001
WeeFIM ${}^{\@setsize{\scriptsize}{8pt}{\viipt}{\@viipt}\textregistered}$ Cognitive DQ ( $n=$ 13)	84.2	30.8	95.1	22.9	$-$ 2.31 ${}^{*}$	0.039
WeeFIM ${}^{\@setsize{\scriptsize}{8pt}{\viipt}{\@viipt}\textregistered}$ TOTAL DQ ( $n=$ 13)	52.5	24.2	74.6	24.9	$-$ 7.55 ${}^{**}$	$<$ 0.001

There were some trends in predicting ability to wean ventilator support. For example, on average, those patients who weaned to any degree were older on admission (average of 93.6 months) than those who did not (average of 67 months). The average length of time between onset of AFM and admission in those that weaned was 9.2 months; this included one significant outlier who was admitted twice, at 25 and 35 months after illness onset. When this patient was excluded, the average dropped to 2.2 months after onset. In contrast, those who were unable to be weaned at all presented an average of 12.75 months after illness onset. This could represent the natural course of the illness, with relatively rapid improvement soon after onset, as well as the increased benefit of early therapy. The outlier mentioned above did make progress but in the setting of a diaphragmatic pacer placement.

Two of the children in our series, both of them belonging to the pre-2015 group, underwent diaphragmatic pacing. One child had no response to stimulation at the time of implantation. His ventilator settings – which we had not been able to wean prior to pacer placement – have since been decreased, but he has not yet been able to pace independent of the ventilator. The second patient, a teenager, had response to stimulation in one hemidiaphragm at implantation. He has been able to pace off the ventilator for short periods of time.

3.3 Rehabilitative outcomes

The Spinal Cord Independence Measure (SCIM) was utilized for 22 of the 31 patients. Out of the 22, 14 were seen for intensive inpatient admissions; the remaining eight were seen as outpatients. Of these, five were seen for a short term bout of therapy, which consists of intensive daily therapy for one to two weeks, limiting their functional changes in such a short period of time. Paired sample $t$ -tests for the 11 inpatients with both admission and discharge scores suggested statistically significant change from admission to discharge. Only 5 of the outpatients had both admission and discharge scores which precluded statistical analysis; however, all 5 patients either maintained or increased raw scores on the SCIM.

All seventeen inpatients were evaluated using the Physical Ability and Mobility Scale (PAMS) during their inpatient admission. This is a 20 question scale created by the Kennedy Krieger Institute to measure 20 skills including: tolerance to positioning, tolerance to sitting in chair, tolerance to orthoses or splint, support for seating system, head control, trunk control, rolling supine to/from prone, transitioning from supine to sit, transitioning from sit to stand, standing, transitioning from floor to stand, environmental transfers, transfers into and out of a car, walking on level ground – assistive device, walking on level ground – distance, walking on level ground – level of assistance, community skills, wheelchair mobility, standing balance, and stairs. Paired sample $t$ -tests showed statistically significant gains from admission to discharge on this measure (Table 4).

The Functional Independence Measure for Children (WeeFIM ${}^{\@setsize{\scriptsize}{8pt}{\viipt}{\@viipt}\textregistered}$ ) was also utilized for 13/17 of the inpatients. Given the wide range of ages, developmental quotient (DQ) scores were used, which represent percent typical for age. As a group, paired $t$ -tests showed statistically significant improvements in self-care, mobility, cognition, and total WeeFIM ${}^{\@setsize{\scriptsize}{8pt}{\viipt}{\@viipt}\textregistered}$ DQ scores, as noted in Table 4.

Clinical muscle testing by therapists demonstrated that improvement in motor function occurred in a distal to proximal pattern, with return of lower limb function seen before upper limb and core/cervical musculature. Despite lower limb motor return, most children continued to require mobility devices for home and community ambulation, although 11 patients did have only upper limb deficits at discharge. These patients were able to ambulate independently, but continued to demonstrate weakness/paralysis in one or both upper extremities and were at high risk for developing shoulder subluxation. The unique presentation of paralysis for those patients who did require assistance with mobility required highly complex or alternative drive controls for wheelchairs. Shoulder paralysis limited manual mobility use; therefore, it was recommended that patients utilize either manual mobility with a power assist mechanism or a power wheelchair. Some examples include: a compact proportional joystick with foot control, Switch-it Microguide light touch miniature joystick with deflection, e-motion power assist wheels, and e-fix power base with proportional joystick. Of the seven patients who were ventilator-dependent, four were able to ambulate short distances with hospital staff, but they continued to demonstrate significantly diminished head control and continued to require ventilator support; therefore, those individuals required wheelchair mobility for community distances and to maximize independence.

The return of motor function from distally to proximally in the majority of patients put them at increased risk for orthopedic deformities including shoulder subluxation, hip subluxation or dislocation, and scoliosis. The majority of patients did not respond well enough to FES using the alternative parameters described above to adequately immobilize the affected joint and prevent chronic damage. Therefore, therapeutic taping and bracing were also used to manage the upper limb subluxations. Many of the commercially available subluxation slings deter use of the arm, which was not appropriate for many of these patients as they had functional use of distal musculature including finger movement. Therefore, it was important to stabilize the shoulder and still allow patients to utilize their existing function in the arm for activities of daily living. Patients were followed closely for hip subluxations. Positioning was adjusted in bed and in the wheelchair per the orthopedic recommendations to decrease the progression of the hip subluxation. Parents were trained in appropriate weight bearing and positioning for home to limit this progression. Bracing was utilized to decrease the progression of scoliosis, although tolerance to the braces was limited. Alternative bracing to the hard Thoracic Lumbar Sacral Orthoses (TLSOs) that are typically used was encouraged in order to increase tolerance to wear time. Patients were able to use the strength in their feet and hands to contour their bodies into less then optimal positions, increasing the progression of these deformities at a higher rate than seen with typical paralysis.

Although not common in our cohort, prior reviews have shown that most patients with AFM display cranial nerve involvement, most commonly in cranial nerves VI, VII, IX, and X [11], which can cause oral sensory and motor problems as well as pharyngeal dysphagia. Individuals with AFM may need alternative forms of communication if tracheostomy placement or mechanical ventilation limit their verbal communication. Assistive technology may be needed to help someone with upper extremity impairments access their environment.

Of the 17 patients admitted to the inpatient unit with AFM, nine required speech-language pathology (SLP) services. The remaining eight were screened by an SLP and did not require services. Of the patients receiving SLP intervention, eight required mechanical ventilation and had g-tubes placed before or during their acute rehabilitation admission. The remaining patient had experienced respiratory failure requiring intubation for 21 days but was extubated prior to transfer to our rehabilitation facility; this patient had an NG tube.

All nine patients requiring SLP services had dysphagia at the time of their admission and received total or supplemental tube feedings. Two patients initially silently aspirated during a videofluoroscopic swallow study (VFSS), but were later cleared for regular diets by a repeat VFSS prior to their discharge. Five patients were not cleared to have any oral intake (NPO) at discharge from the inpatient rehabilitation stay having not undergone VFSS; of these five, four were later cleared for regular diets by a VFSS and one was deceased at follow up (not as a direct result of his AFM). Reasons for not completing a VFSS prior to discharge included refusal behaviors and lack of readiness for oral intake based on clinical and medical evaluation. Two patients who were evaluated in our institute about two years (23 and 26 months) after their illness had already been cleared for a regular diet based on VFSS, but information on when they began eating by mouth was not available. Both had g-tubes for supplemental nutrition and hydration, as they did not meet all of their needs by mouth. Food refusal was a common observation among patients with AFM and ventilator dependence, which affected their participation in swallowing therapy.

Information on dental occlusion was available for six of the patients with long-term ventilator dependence, of which five developed a noticeable underbite. Based on exam, these were considered to be likely the result of weak resting tone for CN V, which can give a slack jaw, and open mouth appearance. In the long term, this can result in a permanent malocclusion (anterior open bite) which requires orthodontic and/or surgical correction once the facial skeleton stops growing in the late teens. Further research is warranted to confirm the cause and functional impact of these underbites and to develop prevention or remediation methods.

Of the eight patients with tracheostomies, information about speaking valve use was available for six patients. One did not tolerate speaking valve placement due to breath stacking. The remaining five patients tolerated the valve from a medical perspective but verbalized discomfort or resisted via nonverbal means (e.g., crying, kicking).

4. Discussion

While AFM was only defined in 2014, cases of sudden onset paralysis in children, mostly involving one limb, were reported prior to 2014. This review included patients from both groups: 14 patients with symptom onset prior to AFM recognition/definition by the CDC, and 17 who presented post AFM definition. Prior to 2014, patients may have been diagnosed with “atypical transverse myelitis,” or “polio-like syndrome,” and the workup was not as prescribed as it is currently. Not knowing that in the future they would be recognized as having AFM, there was no standardization of interventions or evaluation tools. Therefore, we have made no attempt to quantitatively evaluate interventions or outcomes. Another limitation of our review due to the rarity of AFM is the small number of cases, which further restricts any statistical analysis. While our observations (as described earlier and in Tables 3 and 4), suggest potentially significant improvements with ABRT, further evaluation of a greater number of cases undergoing standardized evaluation is needed to make any definitive statements.

For the children in the 2014–2016 period admitted to this center sooner rather than later after the onset of paralysis, a distal to proximal pattern of motor recovery was identified both in children with monoplegia as well as in those with significant tetraplegia and respiratory failure. This leads to the challenge of appropriately supporting/strengthening a weak flaccid shoulder (for which very few effective rehabilitative interventions and/or equipment are available) and ambulating while still dependent on a ventilator. With this unique pattern of return, extensive evaluations, assessments, and collaborative interdisciplinary problem solving were required to achieve maximum therapeutic value.

Many challenges exist as we learn more about these children with AFM over time. These include: the best approach to management of rapidly progressing scoliosis; determining the exact role and optimal timing of surgical interventions (nerve transfers, diaphragmatic pacing, etc.); determining the cause of observed underbites and best prevention or remediation methods; and finding and consistently utilizing outcome measures that document small and functionally meaningful changes.

Phrenic nerve pacing has been performed in children since the mid 1970’s, and is most often used in patients with congenital central hypoventilation syndrome [23]. In 2011, Onders et al. published the first reported pediatric patients with implantation of intramuscular diaphragmatic pacing. Of his initial six patients, two were able to be fully weaned from their ventilators, while the other four were able to be off for over 14 hours a day [24]. This laparoscopic approach is felt to be safer than traditional phrenic nerve stimulator placement; early diaphragmatic pacing may attenuate muscular atrophy of the diaphragm leading to better success in weaning off of positive-pressure mechanical ventilation [25]. Diaphragm pacers were implanted in two children in our cohort. While they both slightly benefitted, neither had a significant decrease in their ventilator dependence time; it may be that earlier initiation of diaphragm pacing will lead to greater improvement. In order for diaphragm pacing to be successful, the phrenic nerve must be intact to the diaphragm. AFM by definition causes damage to the lower motor neuron which may impair phrenic nerve function. However, spinal cord injury in AFM can be incomplete, so there may be cases where the phrenic nerve is spared, and these children may benefit from evaluation for diaphragmatic pacers. Expanding the availability of diaphragm pacing to more medical centers and making it available earlier should lead to improved respiratory outcomes, although further research will be needed.

Nerve transfer surgery has the potential to restore function to affected muscles. For nerve transfer surgery to be successful, surgical intervention must be done before irreversible distal nerve and motor endplate degeneration occurs [26, 27]. Specialists prefer to evaluate patients at about six months post AFM and if recovery of function remains poor, surgical intervention is recommended at about one year (based on discussion with surgeons at our institution, and also literature reviews [28, 29, 30]). Tendon transfers offer another avenue to restore function. The success of these procedures is dependent on available muscle that remains innervated and the functional goals of the patient [27]. Tendon transfers can be done at any time following AFM.

Each patient in our cohort presented with a unique clinical picture. Comprehensive coordination of care was needed among multiple team members to optimize patients’ rehabilitation and monitor their recovery. Patients and families were provided with individualized home rehabilitation programs and equipment was recommended to facilitate continued ABRT in the home environment using the principles listed above. Home programs were customized for each patient and family to meet their continued needs and accommodate their lifestyles. Continued outpatient therapy and recommendations to return to medical and rehabilitation clinic for regular follow up is critical as these patients continue to grow developmentally and change neurologically.

As AFM remains a rare condition, our review is limited statistically by the low numbers of patients affected. New patients however are now more consistently recognized as having AFM and are receiving more standardized evaluations and interventions. Further data collection with this larger population will help us better understand the time frame and pattern of recovery, and which interventions will be of most benefit.

Footnotes

Conflict of interest

No authors have any conflicts of interest to disclose.

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