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.

Association of upper-limb neurological recovery with functional outcomes in high cervical spinal cord injury

OBJECTIVE

High cervical spinal cord injury (SCI) results in complete loss of upper-limb function, resulting in debilitating tetraplegia and permanent disability. Spontaneous motor recovery occurs to varying degrees in some patients, particularly in the 1st year postinjury. However, the impact of this upper-limb motor recovery on long-term functional outcomes remains unknown. The objective of this study was to characterize the impact of upper-limb motor recovery on the degree of long-term functional outcomes in order to inform priorities for research interventions that restore upper-limb function in patients with high cervical SCI.

METHODS

A prospective cohort of high cervical SCI (C1-4) patients with American Spinal Injury Association Impairment Scale (AIS) grade A-D injury and enrolled in the Spinal Cord Injury Model Systems Database was included. Baseline neurological examinations and functional independence measures (FIMs) in feeding, bladder management, and transfers (bed/wheelchair/chair) were evaluated. Independence was defined as score ≥ 4 in each of the FIM domains at 1-year follow-up. At 1-year follow-up, functional independence was compared among patients who gained recovery (motor grade ≥ 3) in elbow flexors (C5), wrist extensors (C6), elbow extensors (C7), and finger flexors (C8). Multivariable logistic regression evaluated the impact of motor recovery on functional independence in feeding, bladder management, and transfers.

RESULTS

Between 1992 and 2016, 405 high cervical SCI patients were included. At baseline, 97% of patients had impaired upper-limb function with total dependence in eating, bladder management, and transfers. At 1 year of follow-up, the largest proportion of patients who gained independence in eating, bladder management, and transfers had recovery in finger flexion (C8) and wrist extension (C6). Elbow flexion (C5) recovery had the lowest translation to functional independence. Patients who achieved elbow extension (C7) were able to transfer independently. On multivariable analysis, patients who gained elbow extension (C7) and finger flexion (C8) were 11 times more likely to gain functional independence (OR 11, 95% CI 2.8-47, p < 0.001) and patients who gained wrist extension (C6) were 7 times more likely to gain functional independence (OR 7.1, 95% CI 1.2-56, p = 0.04). Older age (≥ 60 years) and motor complete SCI (AIS grade A-B) reduced the likelihood of gaining independence.

CONCLUSIONS

After high cervical SCI, patients who gained elbow extension (C7) and finger flexion (C8) had significantly greater independence in feeding, bladder management, and transfers than those with recovery in elbow flexion (C5) and wrist extension (C6). Recovery of elbow extension (C7) also increased the capability for independent transfers. This information can be used to set patient expectations and prioritize interventions that restore these upper-limb functions in patients with high cervical SCI.

Clinically meaningful improvement in disabilities of arm, shoulder, and hand (DASH) following cervical spine surgery

BACKGROUND CONTEXT

Patients with cervical spine disease suffer from upper limb disability. At present, no clinical benchmarks exist for clinically meaningful change in the upper limb function following cervical spine surgery.

PURPOSE

Primary: to establish clinically meaningful metrics; the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) of upper limb functional improvement in patients following cervical spine surgery. Secondary: to identify the prognostic factors of MCID and SCB of upper limb function following cervical spine surgery.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Adult patients ≥18 years of age who underwent cervical spine surgery from 2012 to 2016.

OUTCOME MEASURES

Patient-reported outcomes: Neck disability index (NDI) and Disabilities of Arm, Shoulder, and Hand (DASH).

METHODS

MCID was defined as minimal improvement and SCB as substantial improvement in the DASH score at last follow-up. The anchor-based methods (ROC analyses) defined optimal MCID and SCB thresholds with area under curve (AUC) in discriminating improved vs. non-improved patients. The MCID was also calculated by distribution-based methods: half standard-deviation (0.5-SD) and standard error of the mean (SEM) method. A multivariable logistic regression evaluated the impact of baseline factors in achieving the MCID and SCB in DASH following cervical spine surgery.

RESULTS

Between 2012 and 2016, 1,046 patients with average age of 57±11.3 years, 53% males, underwent cervical spine surgery. Using the ROC analysis, the threshold for MCID was -8 points with AUC of 0.73 (95% CI: 0.67-0.79) and the SCB was -18 points with AUC of 0.88 (95% confidence interval [CI]: 0.85-0.91). The MCID was -11 points by 0.5-SD and -12 points by SEM-method. On multivariable analysis, patients with myelopathy had lower odds of achieving MCID and SCB, whereas older patients and those with ≥6 months duration of symptoms had lower odds of achieving DASH MCID and SCB respectively.

CONCLUSIONS

In patients undergoing cervical spine surgery, MCID of -8 points and SCB of -18 points in DASH improvement may be considered clinically significant. These metrics may enable evaluation of minimal and substantial improvement in the upper extremity function following cervical spine surgery.

Abstract TP447: Angiotensin II Increases Glymphatic Flow Through a Norepinephrine-dependent Mechanism

Background and Objective: The CNS possesses the astrocyte-dependent perivascular glymphatic pathway to facilitate CSF-ISF exchange and clearance of interstitial wastes. Cerebral arterial pulsations drive glymphatic flow, and cerebrovascular pulsatility is dependent, at least in part, on systemic blood pressure. Renin-angiotensin-aldosterone axis dysregulation is responsible for hypertension, a condition that affects nearly 30% of the US population and 40% of individuals globally. Here, we investigate how manipulation of the RAA axis, both with angiotensin and common anti-hypertensive pharmacotherapy, influences glymphatic flow.

Methods: All drugs were administered to the cisterna magna via cannulation at a rate of 1 μL/min for a total volume of 5 μL. Immediately after, 1% AlexaFluor-555 conjugated bovine serum albumin (BSA-555) was delivered intracisternally at a rate of 2 μL/min for a total volume of 10 μL. 30 minutes following tracer injection, cerebral tissues were collected and processed for ex vivo conventional fluorescence microscopy. Tissue area occupied by fluorophore was quantified, with greater percent areas indicating increased glymphatic influx.

Results: Pre-treatment with Angiotensin II (ATII, 1 μM) increased glymphatic influx relative to vehicle-injected controls. Losartan (1 μM), an AT1 receptor inhibitor, was found to decrease glymphatic CSF influx, indicating that ATII acts through the AT1 receptor to increase glymphatic flow. Systemic administration of DSP-4 (50 mg/kg), a neurotoxin known to deplete locus coeruleus norepinephrine, resulted in suppressed glymphatic influx. Co-administration of ATII in DSP-4 treated mice or in mice receiving a norepinephrine inhibitory cocktail (1 μM) resulted in decreased glymphatic influx, suggesting that ATII regulates glymphatic pathway function through a NE-dependent mechanism.

Conclusions: Angiotensin II acts via the AT1 receptor to increase glymphatic influx in a norepinephrine-dependent manner. Further study on hemodynamic regulation of glymphatic flow may reveal mechanisms of hypertension-related brain pathology.

Straight from the horse's mouth: neurological injury in equestrian sports

Objectives

Equestrian sports can result in a variety of injuries to the nervous system due to many factors. We describe our series of 80 patients with injuries sustained during participation in equestrian sports.

Methods and Results

All patients seen at the regional trauma center with injuries associated with equestrian sports between 2003 and 2011 were reviewed; 80 patients were identified. Fifty-four per cent were female and the average age was 37 years (2·2–79·3). The mean injury severity score (ISS) was 9·9 ± 0·7. Only two patients had documented helmet use. Glasgow coma score (GCS) was 15 in 93% of patients. The most common neurosurgical injuries were to the cranial vault (28%), including concussions, intracranial hematomas and hemorrhages, and skull, facial, and spine fractures (10%), with the majority (63%) being transverse process fractures. The mechanisms of injury varied: 55% were kicked or stepped on, 28% were thrown or fell off, and 21% were injured by the horse falling on them. The causes ranged from carelessness and lack of attention to animal factors including inadequate training of horses and animal fear. Fourteen per cent required surgery. There were no mortalities and average length of stay was 3·7 ± 0·35 days. All patients were discharged home with 95% requiring no services.

Discussion

Equestrian sports convey special risks for its participants. With proper protection and precautions, a decrease in the incidence of central nervous system injuries may be achieved. Neurosurgeons can play key roles in advocating for neurologic safety in equestrian sports.

[Paraneoplastic acrokeratosis (Bazex syndrome)]

Bazex acrokeratosis was found in a 79-year-old man with squamous cell carcinoma of the lung. The psoriasiform skin lesions preceded the tumor diagnosis by 8 months. The symptoms, the course of the disease, and histological findings are presented. Acrokeratosis paraneoplastica is a rare disease observed only in patients either with cancer of the upper aerodigestive tract or cervical lymph-node metastases.