Abstract
Context/Objective
To assess short-term changes in health outcomes in people with cervical-level spinal cord injury (SCI) who underwent upper extremity (UE) reconstruction via either novel nerve transfer (NT) or traditional tendon transfer (TT) surgery with individuals who did not undergo UE surgical reconstruction.
Design
Prospective, comparative cohort pilot study.
Participants
34 participants with cervical SCI met the following inclusion criteria: age 18 or older, greater than 6 months post-injury, and mid-cervical level SCI American Spinal Injury Association Impairment Scale (AIS) A, B or C.
Setting
Two tertiary academic hospitals and their affiliated veterans’ hospitals.
Methods
Health outcomes were assessed using two previously validated measures, the Spinal Cord Independence Measure (SCIM) and Short-Form Health Survey (SF-36). Demographic, surgical, and survey data were collected at the initial evaluation and one month postoperatively/post-baseline.
Results
34 participants with cervical SCI were recruited across three cohorts: no surgery (n = 16), NT (n = 10), and TT (n = 8). The TT group had a decline in SCIM and SF-36 scores whereas the NT and no surgery groups experienced little change in independence or health status in the immediate perioperative period.
Conclusions
Surgeons and rehabilitation providers must recognize differences in the perioperative needs of people with cervical SCI who chose to have restorative UE surgery. Future work should focus on further investigation of health outcomes, change in function, and improving preoperative counseling and cross-disciplinary management.
Keywords: Tendon transfer surgery, Nerve transfer surgery, Upper extremity reconstruction, Perioperative rehabilitation, Cervical spinal cord injury, Tetraplegia, Health outcomes
Introduction
People with cervical spinal cord injury (SCI) identify improvements in upper extremity function as their top priority, more critical than even ambulation, sexual function or bowel/bladder function(1). Function can be improved using traditional tendon transfer (TT) or relatively novel nerve transfer (NT) surgical techniques (2). The recent adaptation of NT to SCI has expanded the treatment options (2–4) but increased the complexity of surgical decision-making and planning for post-surgical rehabilitation (5–7).
In TTs, expendable donor tendons are cut, re-routed, and sutured to restore the movement of an otherwise paralyzed muscle (8). A period of immobilization is required to protect the tendon coaptation. In people who rely on their hands to accomplish all activities of daily living, these restrictions may have serious ramifications, including potential risk of deconditioning and pressure sores. The use of the operative extremity for pressure-relieving maneuvers and manual wheelchair use are typically restricted for at least 3 months (4). Vigorous activities such as weight-lifting, contact sports, and bed-to-chair transfers may require long-term adaptations and modifications in technique.
NTs restore movement by re-routing expendable donor to non-functional recipient nerves (9). Reinnervation of the previously paralyzed muscles and gains in movement occur months after surgery. Because the native musculotendinous unit remains intact, typically no immobilization is required, and light use of the operative extremity is allowed even immediately post-surgery. Skin and soft tissue must heal so full weight-bearing and manual wheelchair use is limited for 2–4 weeks post-surgery. Vigorous activity is permitted at 1–2 months post-surgery. The differences between the recovery and therapy protocols of the two procedures (in the current literature and within the US healthcare setting) are further detailed in Table 1.
Table 1.
Comparison of postoperative recovery after tendon and nerve transfer surgeries. (©2023, Ida K. Fox, MD, Washington University in St. Louis).
| Surgery Type | Tendon Transfer | Nerve Transfer |
|---|---|---|
| General Information | ||
| Hospital Stay | 0–7 days (varies) | 0–1 d |
| Short-term Inpatient Rehab | Yes (ideally) | No |
| Use of Operative Extremity | ||
| Immediately post-surgery | Not allowed | Allowed (light/coffee cup weight-bear only) |
| Two weeks post-surgery | Not allowed except for therapy exercises | Allowed (can begin to use manual wheelchair, weight-bear as tolerated for transfers) |
| Four weeks post-surgery | Not allowed except for therapy exercises | Allowed (can resume most activities except sports and weight-lifting) |
| Eight weeks post-surgery | Allowed (light activities and therapy exercises) | No restrictions |
| Twelve weeks post-surgery | Allowed (can resume most activities; sports and transfers may require modification) | No restrictions |
| Incisions (vary depending on surgery being done) | ||
| Number of incisions | 1–8 incisions | 1–3 incisions |
| Length of incisions | 2–6 in. | 2–4 in. |
| Location of incisions | Side of forearm, back of wrist and hand, on fingers and thumb, back of shoulder/elbow, leg for tendon graft harvest | Inner upper arm, back or front of forearm, back of shoulder |
| Dressings/Splint | ||
| Immediately post-surgery | Post-surgical dressing with hard splint inside (length of splint on arm varies by procedure) | Light bandage dressing (covers incisions; fingers/hand are open to air) |
| 2 weeks post-surgery | Dressing typically replaced with cast or removable plastic splint | None |
| 4 weeks post-surgery | Removable plastic splint | None |
| ACTIVITIES OF DAILY LIVING (ADL’s) – with operative arm | ||
| Self-feeding | ||
| Immediately post-surgery | Not allowed | Allowed |
| 8–12 weeks post-surgery | Allowed | Allowed |
| Self-catheterization | ||
| Immediately post-surgery | Not allowed | Allowed |
| 8–12 weeks post-surgery | Allowed | Allowed |
| Bowel regimen | ||
| Immediately post-surgery | Not allowed to lie on operative side | Allowed to lie on operative side |
| 8–12 weeks post-surgery | Allowed to lie on operative side | Allowed to lie on operative side |
| Bathing | ||
| Immediately post-surgery | Not allowed; keep operative arm clean and dry | Allowed to remove dressing in 48 h and wash gently (no soaks) |
| 8–12 weeks post-surgery | Allowed | Allowed |
| THERAPY, EQUIPMENT AND OTHER ACTIVITIES | ||
| Postoperative Equipment & Assistance | Hoyer lift and power wheelchair are helpful to avoid overuse immediately after surgery | |
| Additional help from caretaker while unable to bear weight (and for assistance with ADL’s) | ||
| Duration | 12 weeks after tendon transfer | 2–8 weeks after nerve transfer |
| Therapy | ||
| Formal Therapy | Typically begins at 0–4 weeks post-surgery | Typically begins at 2 weeks post-surgery |
| Frequency/Duration | 2–3 times weekly for 3–6 months post-surgery | 1–2 times monthly for first year (more if joint stiffness is present) |
| Home Exercise Program (HEP) | 2–4 times a day for 1–3 months post-surgery | 2–4 times a day for 1–3 months after new motions are gained (continued HEP for years after surgery improves function) |
| Exercise/Sports | Allowed at 3–6 months post-surgery (may require modification) | Allowed at 1–2 months post-surgery |
| Driving | Allowed at 3 months post-surgery | Allowed at 1–2 months post-surgery |
Both of these surgical treatments offer meaningful improvements and can be used to restore elbow extension, wrist extension and/or hand opening and closing (pinch and grip). In Curtin et al.’s systemic review of outcomes after TT surgery; elbow extension improved from muscle strength of 0/5 preoperatively to 3.3/5 post-operatively and pinch strength improved from 0 to 2 kg (10). These results are maintained in the long-term. For example, one study with 21 years of post-operative follow-up showed <20% diminution in results for individuals who underwent restoration of elbow extension and pinch using TT techniques; another showed loss in strength commensurate with the normal effects of aging (11). Outcomes after NT surgery are more variable. One series reported that 92% of recipient muscles recovered from 0/5 to 4/5 strength post-operatively; another noted that only 25–50% of recipients gained 3/5 strength (2, 12). Longer-term results are not yet available for the nascent application of NT to SCI; but use of NT in peripheral nerve injury supports continued gains with time after surgery (13).
Despite their effectiveness (14–16), restorative surgeries remain underutilized. As few as 8–14% of eligible persons with cervical SCI undergo upper extremity reconstruction (17, 18). Reasons for this low usage are multifactorial and include the limited information available about the immediate perioperative recovery period (19). Despite its vital role in surgical decision-making, the impact of post-surgical activity restrictions in NT compared to TT remains ill-defined (4). The purpose of this prospective cohort study was to assess short-term changes in function and health status in people with cervical-level SCI who underwent NT and/or TT upper extremity reconstruction or no surgery. We hypothesized that people undergoing TTs would experience decreased function and health status post-surgery compared to persons undergoing NTs or no surgical intervention.
Methods
This multicenter pilot study was approved by institutional and grant funding agency human study review boards. Eligible participants included adults (18 years old or older), greater than 6 months post-injury with mid-cervical level SCI American Spinal Injury Association Impairment Scale (AIS) A, B or C. These individuals are candidates for NT or TT surgery as they have expendable functioning donors but lack some upper extremity function such as wrist/elbow extension and/or hand opening/closing (19). People with AIS D status were excluded as they may have motor function below the level of the SCI and would not routinely be offered upper extremity surgical intervention.
Individuals were counseled and treatment decisions were based on preoperative findings and their preferences. All eligible participants were then invited to participate in the study procedures. Following signed informed consent, participants were consecutively categorized to the TT, NT or non-surgical cohort. In clinical practice, NT and TT may be combined. When combined in the same extremity, the postoperative recovery period was defined by the restrictions for the tendon transfer. Thus, individuals who chose to undergo simultaneous tendon and nerve transfer procedures were grouped into the TT cohort.
Demographic data included socio-demographic information, SCI injury information and medical co-morbidities and were categorized using the National Institute of Neurological Disorders and Stroke Common Data Elements definitions and categories (http://www.commondataelements.ninds.nih.gov/).
Participants were assessed at baseline (preoperatively for the surgical group) and within a one month later/postoperative follow-up time point. Function and health status were assessed using two standardized, validated surveys: the self-reported version of the Spinal Cord Independence Measure (SCIM) and 36-item Short Form Health Survey with the walk-wheel modification (SF-36).
The SCIM evaluates the ability of participants to perform important activities of daily living in the setting of SCI and is highly dependent on upper extremity function. There are 19 items in the SCIM (total score of 100), which includes 3 subscales; self-care (scored 0–20), respiration and sphincter management (scored 0–40) and mobility (scored 0–40). Higher scores reflect more independence and lower scores reflect the need for greater assistance (20–25). The self-reported version of the SCIM assessment was utilized in this study (26).
The SF-36 is widely used to assess health-related function and well-being (27, 28). It consists of eight domains; lower scores indicate a lower health status. The SF-36 “wheel/walk modification” uses this same core metric with three additional questions where “walk” was replaced with “wheel” to evaluate functional status to better capture functional status for people with SCI. The walk/wheel modification has been shown to be reliable and valid measure for use in the SCI population (29).
Data analysis
Cervical level SCI is a rare disease and the number of patients undergoing surgical intervention in the United States is relatively small, particularly for individuals undergoing NT (17). Subsequently, limited data were available to conduct an a priori power analysis to estimate sample size. This study serves as a pilot study to establish preliminary data in this population. Therefore, we decided to recruit and enroll approximately 10 individuals per surgical group matched with 20 non-surgical individuals.
Demographic data were summarized using descriptive statistics. All scores and changes in scores over time for the SCIM and the SF-36 data were assessed within groups and between groups. Differences between groups were assessed used Wilcoxon sum-rank test and within groups using Wilcoxon signed-rank test. Significance was defined using a P value of < 0.05. All analyses were performed using R version 3.5.2.
Results
Demographics, comorbidities, and psychosocial factors
There were 40 participants with cervical-level SCI enrolled in the study. Individuals were excluded from analysis if data were missing, such as no preoperative visit (n = 2), incomplete baseline surveys (n = 1) or missing follow-up surveys (n = 3). The study sample included 34 participants with complete data: no surgery (n = 16), NT (n = 10), and TT (n = 8). Supplemental Table 1 details the specific TT and NT surgeries that were performed.
Table 2 presents the summary of socio-demographic, mechanism of injury information and medical co-morbidity data. Individuals undergoing TT were significantly (p = 0.05) older at the time of SCI (41.2 ± 17.1 years) compared to those who chose no surgery (27.3 ± 14.1 years). They were also significantly (p = 0.04) closer to the time of SCI (TT 3.0 ± 1.6 years vs. no surgery 11.8 ± 10.4 years). These differences were not statistically significant when compared to the NT group. There were no other significant differences between groups.
Table 2.
Participant demographics.
| Variable | All | No Surgery | Nerve Transfer | Tendon Transfer | p value | ||
|---|---|---|---|---|---|---|---|
| No Surgery vs. Nerve | No Surgery vs. Tendon | Nerve Vs Tendon | |||||
| N | 34 | 16 | 10 | 8 | |||
| “Current” Age | 0.812 | 0.408 | 0.244 | ||||
| Mean | 39.6 | 39.0 | 38.2 | 44.2 | |||
| Median | 37 | 36.0 | 36.5 | 42.0 | |||
| St. Dev. | 14.2 | 13.6 | 15.3 | 16.5 | |||
| Age at Spinal Cord Injury | 0.267 | 0.047** | 0.174 | ||||
| Mean | 31.0 | 27.3 | 31.8 | 41.2 | |||
| Median | 24.0 | 22.5 | 28.0 | 38.0 | |||
| St. Dev. | 15.3 | 14.1 | 15.2 | 17.1 | |||
| Years from Spinal Cord Injury | 0.081 | 0.035** | 1.000 | ||||
| Mean | 8.6 | 11.8 | 6.4 | 3.0 | |||
| Median | 5.0 | 9.0 | 2.0 | 3.0 | |||
| St. Dev. | 9.2 | 10.4 | 7.8 | 1.6 | |||
| Sex | 0.538 | 0.361 | 1.000 | ||||
| Male | 87.1% | 93.8% | 80.0% | 80.0% | |||
| Female | 12.9% | 6.3% | 20.0% | 20.0% | |||
| Veteran | 0.701 | 1.000 | 0.608 | ||||
| No | 51.6% | 50.0% | 60.0% | 40.0% | |||
| Yes | 48.4% | 50.0% | 40.0% | 60.0% | |||
| Etiology | 0.970 | 0.878 | 0.627 | ||||
| Sports/Leisure | 25.8% | 25.0% | 30.0% | 20.0% | |||
| Assault | 3.2% | 6.3% | 0.0% | 0.0% | |||
| Transport | 48.4% | 43.8% | 40.0% | 80.0% | |||
| Fall | 16.1% | 18.8% | 20.0% | 0.0% | |||
| Other | 3.2% | 6.3% | 0.0% | 0.0% | |||
| Non-Traumatic Lesion | 3.2% | 0.0% | 10.0% | 0.0% | |||
| Etiology Type | 0.759 | 1.000 | 1.000 | ||||
| Blunt | 87.1% | 81.3% | 90.0% | 100.0% | |||
| Penetrating | 6.5% | 12.5% | 0.0% | 0.0% | |||
| Unknown | 6.5% | 6.3% | 10.0% | 0.0% | |||
| Major Medical Comorbidity | 1.000 | 0.598 | 0.560 | ||||
| No | 74.2% | 75.0% | 80.0% | 60.0% | |||
| Yes | 25.8% | 25.0% | 20.0% | 40.0% | |||
| Other Medical Comorbidity | 0.538 | 0.429 | 1.000 | ||||
| No | 12.9% | 6.3% | 20.0% | 20.0% | |||
| Yes | 87.1% | 93.8% | 80.0% | 80.0% | |||
| Employment | 0.355 | 0.575 | 0.780 | ||||
| Working part time | 3.2% | 6.3% | 0.0% | 0.0% | |||
| Working full time | 9.7% | 6.3% | 20.0% | 0.0% | |||
| On Disability | 64.5% | 56.3% | 60.0% | 100.0% | |||
| Unemployed/Looking for Work | 3.2% | 0.0% | 10.0% | 0.0% | |||
| Unemployed/Not looking for Work | 19.4% | 31.3% | 10.0% | 0.0% | |||
| Living Situation | 1.000 | 1.000 | 1.000 | ||||
| Live by self with caregiver coming in | 12.9% | 12.5% | 10.0% | 20.0% | |||
| Live by self plus live-in caregiver | 3.2% | 6.3% | 0.0% | 0.0% | |||
| Assisted living/rehab | 3.2% | 6.3% | 0.0% | 0.0% | |||
| Live with family or other person | 80.6% | 75.0% | 90.0% | 90.0% | |||
| Who provides Support | 0.486 | 0.642 | 1.000 | ||||
| Family/Partner | 77.4% | 68.8% | 80.0% | 100.0% | |||
| Friend | 3.2% | 0.0% | 10.0% | 0.0% | |||
| Paid Person Not Related | 16.1% | 25.0% | 10.0% | 0.0% | |||
| Other | 3.2% | 6.3% | 0.0% | 0.0% | |||
| Education Level | 0.561 | 0.917 | 0.530 | ||||
| Less than High School | 3.2% | 6.3% | 0.0% | 0.0% | |||
| High School Diploma/GED | 16.1% | 18.8% | 10.0% | 20.0% | |||
| Associate Degree or Trade School | 19.4% | 18.8% | 10.0% | 40.0% | |||
| Some College w/o Degree | 38.7% | 43.8% | 30.0% | 40.0% | |||
| Bachelor's Degree | 12.9% | 6.3% | 30.0% | 0.0% | |||
| Master's Degree | 9.7% | 6.3% | 20.0% | 0.0% | |||
*Major medical comorbidity defined as: cardiovascular disease, diabetes, lung disease, cerebrovascular disease; other medical comorbidity defined as: urinary tract infections, prior pressures sores, spasticity.
**Statistically significant.
SCIM
Total SCIM scores at baseline were significantly (p = 0.03) lower in the NT group (25.8 ± 6.1) compared to the TT group (40.3 ± 9.1) as shown in Fig. 1, reflecting differences in the transfers, self-care, and mobility sub-scores. (Appendix I). Comparison of the change in SCIM scores over time (surgical groups, pre- to postoperative; non-surgical group baseline to 1 month follow-up) showed that TT participants experienced a significantly greater functional decline (P = 0.05) compared to NT participants (−6.1 ± 7 versus 1.5 ± 6.2), as shown in Fig. 2 (raw scores reported in Appendix II). These differences were largely attributable to a decrease in the respiration and sphincter management sub-scores. There were no significant differences in SCIM performance between the NT group and those who did not have surgery (Table 3).
Figure 1.
Baseline SCIM Total Score. Baseline SCIM scores indicate significantly lower functional status in the Nerve Transfer group compared to the Tendon Transfer group, P = 0.003.
Figure 2.
Changes in SCIM Total Score. Change in SCIM total scores and sub-scores from baseline to follow-up reveal significant declines in function of the Tendon Transfer group compared to the Nerve Transfer group, P = 0.05. No change was seen in the no surgery group.
Table 3.
Changes in Spinal Cord Independence Measure III (SCIM) scores across cohorts.
| Change in SCIM: Early Follow-up SCIM – Baseline SCIM | ||||||
|---|---|---|---|---|---|---|
| Variable | No Surgery | Nerve Transfer | Tendon Transfer | p-value | ||
| No Surgery vs. Nerve | No Surgery vs. Tendon | Nerve Vs Tendon | ||||
| N | 16 | 10 | 8 | |||
| Feeding | 0.631 | 1.000 | 1.000 | |||
| Worsen | 0.0% | 10.0% | 0.0% | |||
| No Change | 93.8% | 90.0% | 100.0% | |||
| Improve | 6.3% | 0.0% | 0.0% | |||
| Bladder | 1.000 | 1.000 | 1.000 | |||
| Worsen | 6.3% | 10.0% | 12.5% | |||
| No Change | 93.8% | 90.0% | 87.5% | |||
| Improve | 0.0% | 0.0% | 0.0% | |||
| Transfers | 0.263 | 0.091 | 0.397 | |||
| Worsen | 6.3% | 10.0% | 37.5% | |||
| No Change | 93.8% | 70.0% | 62.5% | |||
| Improve | 0.0% | 20.0% | 0.0% | |||
| SCIM Self Care Subscore | 0.421 | 0.138 | 0.318 | |||
| Mean | 0.4 | 0.6 | −1.5 | |||
| Median | 0.0 | 0.0 | −1.0 | |||
| St. Dev. | 1.3 | 2.6 | 3.0 | |||
| SCIM Respiration and Sphincter Management Subscore | 0.804 | 0.032 | 0.032** | |||
| Mean | 0.3 | 0.2 | −2.4 | |||
| Median | 0.0 | 0.0 | −1.5 | |||
| St. Dev. | 2.7 | 2.6 | 3.3 | |||
| SCIM Mobility Subscore | 0.639 | 0.478 | 0.179 | |||
| Mean | −0.4 | 0.7 | −0.4 | |||
| Median | 0.0 | 0.0 | 0.0 | |||
| St. Dev. | 1.7 | 2.8 | 1.7 | |||
| SCIM Total Score | 0.612 | 0.056 | 0.049** | |||
| Mean | 0.3 | 1.5 | −6.1 | |||
| Median | 1.0 | 0.0 | −7.0 | |||
| St. Dev. | 4.2 | 6.2 | 7.0 | |||
**Statistically significant.
SF-36 domains
Findings from the SF-36 showed no significant baseline differences between groups (Appendix III). The TT group had significantly greater role limitations due to physical health score from baseline to the postoperative follow-up period (25 ± 35.4) when compared to the no surgery group (−7.2 ± 44.5), p = 0.02, as shown in Fig. 3 (raw scores reported in Appendix IV). No significant differences were noted in the NT group compared to the no surgery or TT groups (Table 4).
Figure 3.
SF-36 Change in Physical Functioning, Baseline to Follow-up. The tendon transfer group had a significantly greater changes in role limitations in the immediate postoperative period when compared to the no surgery group, P = 0.02. No significant change was seen in the nerve transfer group. Changes in SF-36 sub-scores in limitations due to physical health demonstrate significantly lower scores (indicating increased physical limitations) in the Tendon Transfer group compared to the Nerve Transfer group, P = 0.02.
Table 4.
Change in Short-Form Health Survey (SF-36) scores across cohorts.
| Change in SF-36: Early Follow-up SF36 – Baseline SF36 | ||||||
|---|---|---|---|---|---|---|
| Variable | No Surgery | Nerve Transfer | Tendon Transfer | p value | ||
| No Surgery vs. Nerve | No Surgery vs. Tendon | Nerve vs. Tendon | ||||
| N | 16 | 10 | 8 | |||
| Physical Functioning (0–100) | 0.669 | 0.062 | 0.304 | |||
| Mean | 0.9 | −7.5 | −13.1 | |||
| Median | 0.0 | 0.0 | −12.5 | |||
| St. Dev. | 15.1 | 30.6 | 16.0 | |||
| Role limitations due to physical health (0–100) | 0.387 | 0.020** | 0.163 | |||
| Mean | −17.2 | −12.5 | 25.0 | |||
| Median | −25.0 | 0.0 | 12.5 | |||
| St. Dev. | 44.5 | 47.5 | 35.4 | |||
| Role limitations due to emotional problems (0–100) | 0.956 | 0.527 | 0.640 | |||
| Mean | −25.0 | −23.3 | −12.5 | |||
| Median | −16.7 | 0.0 | 0.0 | |||
| St. Dev. | 50.9 | 63.0 | 53.3 | |||
| Energy/Fatigue (0–100) | 0.651 | 0.254 | 0.296 | |||
| Mean | 4.7 | −0.5 | −7.5 | |||
| Median | 5.0 | 0.0 | −5.0 | |||
| St. Dev. | 19.3 | 14.4 | 18.9 | |||
| Emotional well-being (0–100) | 0.574 | 0.902 | 0.788 | |||
| Mean | 2.3 | 0.0 | 1.5 | |||
| Median | 4.0 | 2.0 | 4.0 | |||
| St. Dev. | 13.9 | 14.7 | 12.6 | |||
| Social Functioning (0–100) | 0.349 | 1.000 | 0.300 | |||
| Mean | 2.3 | −6.3 | 7.8 | |||
| Median | 12.5 | −6.3 | 6.3 | |||
| St. Dev. | 33.0 | 25.9 | 18.8 | |||
| Pain (0–100) | 0.488 | 0.294 | 0.588 | |||
| Mean | −0.8 | 0.5 | −9.7 | |||
| Median | 0.0 | −5.0 | −10.0 | |||
| St. Dev. | 32.8 | 30.6 | 22.6 | |||
| General Health (0–100) | 0.378 | 0.926 | 0.501 | |||
| Mean | −2.8 | −7.5 | −2.5 | |||
| Median | −2.5 | −5.0 | 0.0 | |||
| St. Dev. | 17.6 | 15.1 | 16.5 | |||
**Statistically significant.
Discussion
Improving upper extremity function is a top priority for people living with SCI. Surgery can be used to restore wrist and elbow extension as well as hand function (30). Individuals with cervical SCI with hand function have greater independence in feeding, urinary, and transfer activities compared to those who do not (31). Current data estimates that 60% to 75% of persons with cervical-level SCI are candidates for restorative upper limb procedures (30). Despite the recent expansion of treatment options to include NT, (2) this population remains underserved (16, 17).
Reasons for this low utilization are multifactorial and include lack of referral networks and disparities in rehabilitation resources. Another barrier to TT surgery is apprehension about the postoperative recovery (19). In one study, 50 individuals with tetraplegia were surveyed about perceptions regarding TT surgery; many stated they were concerned about recovery time post-surgery (32). In a qualitative study of nine individuals who underwent TT a decade or later after SCI, loss of independence was identified as a key reason for delaying surgery (33). In a prospective qualitative study of individuals contemplating TT, there were concerns over the temporary loss of independence as a reason for declining surgery (34).
Additionally, complications can occur after both surgeries and include hematoma, infection, seroma and inflammation. A review of results after 156 TT to restore elbow extension reported complications in 39 limbs with rupture or stretching of the repair (N = 21) being the most common issue(10). Adverse events occurred in 75 of 183 limbs that underwent TT to restore pinch; contracture (N = 19) or stretching of the repair (N = 17) were the most common complications. Transient loss of donor site movement was reported as the main complication in a systemic review of NT surgery in SCI; the incidence was not provided(2, 12). More detailed information on post-operative complications was available for a comprehensive and prospective series of 50 NT’s; these included no gain in movement (N = 4), temporary loss of wrist extension (N = 2) and paresthesias (N = 2). Post-surgical complications affect health-related quality of life and delay resumption of activities of daily living.
Our study corroborated the concerns about the necessary albeit temporary loss of independence immediately after TT surgery. Using the SF-36, we found that individuals undergoing TT reported greater role limitations due to physical health in the postoperative period compared to individuals undergoing NT. Similarly, SCIM scores declined by 6.1 points in the TT group postoperatively; a 4-point change in overall SCIM score is considered clinically meaningful (35). The sphincter / respiratory management sub-score contributed to changes in SCIM scores more-so than other domains. This may be attributable to the postoperative splinting/casting needed in tendon transfer rehabilitation, which could limit the ability to perform finer motor tasks such as self-catheterization in the immediate postoperative period. By contrast, while individuals undergoing NT had lower baseline function compared to the TT group, no postoperative change was seen in SF-36 or SCIM scores for the NT group.
By understanding these differences in immediate postoperative recovery, healthcare providers may better educate, prepare, and manage these individuals. Though critical in any population, preoperative counseling and planning is essential for people with SCI, given the heterogeneity of both personal living situations and access to rehabilitation resources (36). Because of the need for immobilization and non-weight-bearing following TT, these individuals might benefit from a short inpatient rehabilitation unit admission immediately post-surgery. Some countries (e.g. Sweden, New Zealand) have centralized rehabilitation after SCI and upper extremity surgery in this setting; other regions do not and rehabilitation care falls on families. Private insurance in the United States provides limited rehabilitation coverage as does the SCI centers within the Veterans Affairs System of Care (19). Social factors such as access to therapy must be integrated into the surgical decision-making process. Future work to better understand activity modification, adaption, equipment needs, and the role of pre-habilitation is needed. Rehabilitation providers and surgeons need to partner and improve interdisciplinary management in this population.
While traditional tendon transfers have served as the standard of UE reconstruction in cervical SCI, NT may represent a viable alternative. In our study, the NT cohort had lower baseline functional independence than the TT cohort. This finding may reflect the differences in selection and candidacy for surgery. There are biomechanical characteristics that contribute to variations in available donors for NT compared to TT. In individuals with higher level cervical SCI, there may be available donor nerves, but no donor tendons. For example, individuals with a proximal C5 motor level can have finger function restored using donor nerves to the brachialis and supinator muscles (37, 38). However, these same individuals may not be candidates for TT surgery, which typically requires functioning brachioradialis and wrist extensor tendon donors. For these reasons, NTs may expand the population that is eligible for upper extremity reconstructive surgery. The decreased baseline functional independence seen in the NT group may reflect the “expansion” of candidates for upper extremity reconstruction.
Limitations and future directions
Future work is needed to compare outcomes across time points, among treatment options, and in different practice settings. In our study, direct comparison of outcomes is limited by small sample size, limited outcome measures, and heterogeneity in baseline functioning across the study cohorts. The SCIM and SF-36 questionnaires assess overall function and are not specific to the operative extremity; changes may reflect function present in the non-operated extremity. Future work should collect more specific data including standardized measures of movement such as the International Classification for Surgery of the Hand in Tetraplegia (ICSHT), the International Standards for Neurological Classification of Spinal Cord Injury, the American Spinal Injury Association (ASIA) Impairment Scale (AIS), and extremity-specific impairment measurements like the Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) score (39–42). Ideally, participants would be matched across cohorts with respect to C-spine motor level, AIS score, and spasticity. Finally, this study focuses on the perioperative impact on function, which is only one factor for individuals weighing their surgical options. Further long-term data comparing NT and TT outcomes is underway.
Conclusion
There was heterogeneity in the baseline and postoperative function of people with cervical level SCI undergoing surgery to improve upper extremity function. After TT, there was a decrease in independence and health status that was not seen in the non-surgical or NT cohorts. These findings may have implications for perioperative planning and informed decision-making as we seek to improve access to restorative upper extremity surgery.
Supplementary Material
Acknowledgements
We wish to thank Joel Vetter for statistical analysis assistance and Kelley Chadwick-Mansker and Deborah Kenney for study recruitment, data collection and coordination. The contents of this work do not represent the views of the U.S. Department of Veterans Affairs or the United States Government.
Appendix I. Baseline SCIM scores across cohorts.
| Baseline SCIM | ||||||
|---|---|---|---|---|---|---|
| Variable | No Surgery | Nerve Transfer | Tendon Transfer | p value | ||
| No Surgery vs. Nerve | No Surgery vs. Tendon | Nerve Vs Tendon | ||||
| N | 16 | 10 | 8 | |||
| Feeding | 0.057 | 0.078 | - | |||
| Full Assist | 25.0% | 0.0% | 0.0% | |||
| Partial Assist | 56.3% | 100.0% | 100.0% | |||
| Independent | 18.8% | 0.0% | 0.0% | |||
| Bladder | 0.617 | 0.631 | 1.000 | |||
| Full Assist | 75.0% | 90.0% | 87.5% | |||
| Independent | 25.0% | 10.0% | 12.5% | |||
| Transfers | 0.581 | 0.032** | 0.004** | |||
| Full Assist | 50.0% | 70.0% | 0.0% | |||
| Partial Assist | 37.5% | 30.0% | 62.5% | |||
| Independent | 12.5% | 0.0% | 37.5% | |||
| SCIM Self Care Subscore | 0.131 | 0.975 | 0.002** | |||
| Median | 9.5 | 3.5 | 8.5 | |||
| SCIM Respiration and Sphincter Management Subscore | 0.089 | 0.254 | <0.001** | |||
| Median | 16.0 | 17.0 | 19.0 | |||
| SCIM Mobility Subscore | 0.089 | 0.254 | <0.001** | |||
| Median | 8.5 | 4.0 | 11.5 | |||
| SCIM Total Score | 0.154 | 0.374 | 0.003** | |||
| Median | 34.5 | 26.0 | 39.5 | |||
**Statistically significant.
Appendix II. Early follow-up SCIM scores across cohorts
| Early Follow-up SCIM | ||||||
|---|---|---|---|---|---|---|
| Variable | No Surgery | Nerve Transfer | Tendon Transfer | p value | ||
| No Surgery vs. Nerve | No Surgery vs. Tendon | Nerve Vs Tendon | ||||
| N | 16 | 10 | 8 | |||
| Feeding | 0.367 | 0.152 | 1.000 | |||
| Full Assist | 18.8% | 10.0% | 0.0% | |||
| Partial Assist | 62.5% | 90.0% | 100.0% | |||
| Independent | 18.8% | 0.0% | 0.0% | |||
| Bladder | 0.262 | 0.526 | - | |||
| Full Assist | 81.3% | 100.0% | 100.0% | |||
| Independent | 18.8% | 0.0% | 0.0% | |||
| Transfers | 0.699 | 0.436 | 0.171 | |||
| Full Assist | 56.3% | 60.0% | 25.0% | |||
| Partial Assist | 31.3% | 40.0% | 50.0% | |||
| Independent | 12.5% | 0.0% | 25.0% | |||
| SCIM Self Care Subscore | 0.153 | 0.689 | 0.153 | |||
| Mean | 8.9 | 4.7 | 7.8 | |||
| Median | 9.0 | 4.5 | 7.0 | |||
| St. Dev. | 6.8 | 3.3 | 4.4 | |||
| SCIM Respiration and Sphincter Management Subscore | 0.689 | 0.536 | 0.821 | |||
| Median | 16.5 | 19.0 | 16.0 | |||
| SCIM Mobility Subscore | 0.122 | 0.621 | 0.026** | |||
| Median | 8.0 | 3.0 | 9.5 | |||
| SCIM Total Score | 0.215 | 1.000 | 0.130 | |||
| Median | 39.5 | 25.5 | 32.5 | |||
**Statistically significant.
Appendix III. Baseline SF-36 scores
| Baseline SF-36 | ||||||
|---|---|---|---|---|---|---|
| Variable | No Surgery | Nerve Transfer | Tendon Transfer | p value | ||
| No Surgery vs. Nerve | No Surgery vs. Tendon | Nerve Vs Tendon | ||||
| N | 16 | 10 | 8 | |||
| Physical Functioning (0–100) | 0.146 | 0.454 | 0.113 | |||
| Median | 30.0 | 17.5 | 35.0 | |||
| Role limitations due to physical health (0–100) | 0.666 | 0.771 | 0.473 | |||
| Median | 87.5 | 100.0 | 75.0 | |||
| Role limitations due to emotional problems (0–100) | 0.114 | 0.949 | 0.207 | |||
| Median | 66.7 | 100.0 | 50.0 | |||
| Energy/Fatigue (0–100) | 0.916 | 0.186 | 0.244 | |||
| Median | 50.0 | 50.0 | 62.5 | |||
| Emotional well-being (0–100) | 0.979 | 0.757 | 0.655 | |||
| Median | 72.0 | 76.0 | 72.0 | |||
| Social Functioning (0–100) | 0.958 | 0.494 | 1.000 | |||
| Median | 62.5 | 68.8 | 56.3 | |||
| Pain (0–100) | 0.750 | 0.355 | 0.261 | |||
| Median | 68.8 | 62.5 | 80.0 | |||
| General Health (0–100) | 0.958 | 0.185 | 0.305 | |||
| Median | 60.0 | 52.5 | 67.5 | |||
Appendix IV. Early follow-up SF-36 scores
| Early Follow-up SF-36 | ||||||
|---|---|---|---|---|---|---|
| Variable | No Surgery | Nerve Transfer | Tendon Transfer | p value | ||
| No Surgery vs. Nerve | No Surgery vs. Tendon | Nerve Vs Tendon | ||||
| N | 16 | 10 | 8 | |||
| Physical Functioning (0–100) | 0.050** | 0.239 | 0.788 | |||
| Median | 30.5 | 15.0 | 20.0 | |||
| Role limitations due to physical health (0–100) | 0.362 | 0.019** | 0.313 | |||
| Median | 62.5 | 100.0 | 100.0 | |||
| Role limitations due to emotional problems (0–100) | 0.225 | 0.660 | 0.583 | |||
| Median | 0.0 | 33.3 | 0.0 | |||
| Energy/Fatigue (0–100) | 0.634 | 0.950 | 0.721 | |||
| Median | 52.5 | 50.0 | 52.0 | |||
| Emotional well-being (0–100) | 0.653 | 0.758 | 0.561 | |||
| Median | 76.0 | 72.0 | 80.0 | |||
| Social Functioning (0–100) | 0.230 | 0.851 | 0.368 | |||
| Median | 75.0 | 50.0 | 75.0 | |||
| Pain (0–100) | 0.730 | 0.951 | 0.530 | |||
| Median | 68.8 | 57.5 | 62.5 | |||
| General Health(0–100) | 0.937 | 0.255 | 0.422 | |||
| Median | 60.0 | 62.5 | 75.0 | |||
**Statistically significant.
Statement of informed consent
Informed consent was obtained from all patients for being included in the study.
Statement of human rights
All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008.
Disclaimer statements
Contributors None.
Funding This work was supported by the Department of Defense-W81XWH-17-1-0285 Supporting Patient Decisions about Upper-Extremity Surgery in Cervical SCI (PI Ida K. Fox, MD). This material is the result of work supported with resources and the use of facilities at the Veterans Healthcare Systems in St. Louis, MO and Palo Alto, CA. The contents of this work do not represent the views of the U.S. Department of Veterans Affairs or the United States Government.
Conflicts of interest Authors have no conflict of interests to declare.
Supplemental data
Supplemental data for this article can be accessed online at https://doi.org/10.1080/10790268.2023.2283238.
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