Spontaneous Motor Recovery after Cervical Spinal Cord Injury: Issues for Nerve Transfer Surgery Decision Making

Impact of Upper Limb Motor Recovery on Functional Independence After Traumatic Low Cervical Spinal Cord Injury

Cervical spinal cord injury (SCI) causes devastating loss of upper limb function and independence. Restoration of upper limb function can have a profound impact on independence and quality of life. In low-cervical SCI (level C5-C8), upper limb function can be restored via reinnervation strategies such as nerve transfer surgery. The translation of recovered upper limb motor function into functional independence in activities of daily living (ADLs), however, remains unknown in low cervical SCI (i.e., tetraplegia). The objective of this study was to evaluate the association of patterns in upper limb motor recovery with functional independence in ADLs. This will then inform prioritization of reinnervation strategies focused to maximize function in patients with tetraplegia. This retrospective study performed a secondary analysis of patients with low cervical (C5-C8) enrolled in the SCI Model Systems (SCIMS) database. Baseline neurological examinations and their association with functional independence in major ADLs-i.e., eating, bladder management, and transfers (bed/wheelchair/chair)-were evaluated. Motor functional recovery was defined as achieving motor strength, in modified research council (MRC) grade, of ≥ 3 /5 at one year from ≤ 2/5 at baseline. The association of motor function recovery with functional independence at one-year follow-up was compared in patients with recovered elbow flexion (C5), wrist extension (C6), elbow extension (C7), and finger flexion (C8). A multi-variable logistic regression analysis, adjusting for known factors influencing recovery after SCI, was performed to evaluate the impact of motor function at one year on a composite outcome of functional independence in major ADLs. Composite outcome was defined as functional independence measure score of 6 or higher (complete independence) in at least two domains among eating, bladder management, and transfers. Between 1992 and 2016, 1090 patients with low cervical SCI and complete neurological/functional measures were included. At baseline, 67% of patients had complete SCI and 33% had incomplete SCI. The majority of patients were dependent in eating, bladder management, and transfers. At one-year follow-up, the largest proportion of patients who recovered motor function in finger flexion (C8) and elbow extension (C7) gained independence in eating, bladder management, and transfers. In multi-variable analysis, patients who had recovered finger flexion (C8) or elbow extension (C7) had higher odds of gaining independence in a composite of major ADLs (odds ratio [OR] = 3.13 and OR = 2.87, respectively, p < 0.001). Age 60 years (OR = 0.44, p = 0.01), and complete SCI (OR = 0.43, p = 0.002) were associated with reduced odds of gaining independence in ADLs. After cervical SCI, finger flexion (C8) and elbow extension (C7) recovery translate into greater independence in eating, bladder management, and transfers. These results can be used to design individualized reinnervation plans to reanimate upper limb function and maximize independence in patients with low cervical SCI.

Nerve Transfer After Cervical Spinal Cord Injury: Who Has a "Time Sensitive" Injury Based on Electrodiagnostic Findings?

OBJECTIVE

To use the ulnar compound muscle action potential (CMAP) to abductor digiti minimi (ADM) to identify the proportion of individuals with cervical spinal cord injury (SCI) who have lower motor neuron (LMN) abnormalities involving the C8-T1 spinal nerve roots, within 3-6 months, and thus may influence the response to nerve transfer surgery.

DESIGN

Retrospective analysis of prospectively collected data. Data were analyzed from European Multicenter Study About SCI database.

SETTING

Multi-center, academic hospitals.

PARTICIPANTS

We included 79 subjects (age=41.4±17.7, range:16-75; 59 men; N=79), who were classified as cervical level injuries 2 weeks after injury and who had manual muscle strength examinations that would warrant consideration for nerve transfer (C5≥4, C8<3).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The ulnar nerve CMAP amplitude to ADM was used as a proxy measure for C8-T1 spinal segment health. CMAP amplitude was stratified into very abnormal (<1.0 mV), sub-normal (1.0-5.9 mV), and normal (>6.0 mV). Analysis took place at 3 (n=148 limbs) and 6 months (n=145 limbs).

RESULTS

At 3- and 6-month post-injury, 33.1% and 28.3% of limbs had very abnormal CMAP amplitudes, respectively, while in 54.1% and 51.7%, CMAPs were sub-normal. Median change in amplitude from 3 to 6 months was 0.0 mV for very abnormal and 1.0 mV for subnormal groups. A 3-month ulnar CMAP <1 mV had a positive predictive value of 0.73 (95% CI 0.69-0.76) and 0.78 (95% CI 0.75-0.80) for C8 and T1 muscle strength of 0 vs 1 or 2.

CONCLUSION

A high proportion of individuals have ulnar CMAPs below the lower limit of normal 3- and 6-month post cervical SCI and may also have intercurrent LMN injury. Failure to identify individuals with LMN denervation could result in a lost opportunity to improve hand function through timely nerve transfer surgeries.

[Surgical reconstruction of arm and hand functions in tetraplegia : Current concepts]

The reconstruction of arm and hand functions is of enormous importance for tetraplegic patients as it enables at least some degree of independence. Depending on the level of the spinal cord injury, certain residual functions are present in the arms which can be used for surgical reconstruction of upper extremity functions. By utilizing tendon and nerve transfers missing functions can at least be partially reconstructed. Tendon transfers are a proven technique with reliable results that can be performed at any time regardless of the type of accident. Due to the frequent presence of lower motor neuron damage, it is essential to consider the optimal time window for nerve transfer interventions. From the multitude of surgical options, an individual reconstruction plan must be created for each patient, which considers multiple factors. The combination of nerve transfers and later completing the functional reconstruction by tendon transfers is the preferred concept of the authors of this article.

Assessing an Online Patient Decision Aid about Upper Extremity Reconstructive Surgery for Cervical Spinal Cord Injury: Pilot Testing Knowledge, Decisional Conflict, and Acceptability

Background. While nerve and tendon transfer surgery can restore upper extremity function and independence after midcervical spinal cord injury, few individuals (∼14%) undergo surgery. There is limited information regarding these complex and time-sensitive treatment options. Patient decision aids (PtDAs) convey complex health information and help individuals make informed, preference-consistent choices. The purpose of this study is to evaluate a newly created PtDA for people with spinal cord injury who are considering options to optimize upper extremity function. Methods. The PtDA was developed by our multidisciplinary group based on clinical evidence and the Ottawa Decision Support Framework. A prospective pilot study enrolled adults with midcervical spinal cord injury to evaluate the PtDA. Participants completed surveys about knowledge and decisional conflict before and after viewing the PtDA. Acceptability measures and suggestions for further improvement were also solicited. Results. Forty-two individuals were enrolled and completed study procedures. Participants had a 20% increase in knowledge after using the PtDA (P < 0.001). The number of participants experiencing decisional conflict decreased after viewing the PtDA (33 v. 18, P = 0.001). Acceptability was high. To improve the PtDA, participants suggested adding details about specific surgeries and outcomes. Limitations. Due to the COVID-19 pandemic, we used an entirely virtual study methodology and recruited participants from national networks and organizations. Most participants were older than the general population with a new spinal cord injury and may have different injury causes than typical surgical candidates. Conclusions. A de novo PtDA improved knowledge of treatment options and reduced decisional conflict about reconstructive surgery among people with cervical spinal cord injury. Future work should explore PtDA use for improving knowledge and decisional conflict in the nonresearch, clinical setting.

Highlights

People with cervical spinal cord injury prioritize gaining upper extremity function after injury, but few individuals receive information about treatment options.A newly created patient decision aid (PtDA) provides information about recovery after spinal cord injury and the role of traditional tendon and newer nerve transfer surgery to improve upper extremity upper extremity function.The PtDA improved knowledge and decreased decisional conflict in this pilot study.Future work should focus on studying dissemination and implementation of the ptDA into clinical practice.