BWSTT in Acute/Sub-Acute SCI

Discussion

We found 18 studies that have examined the effect of Lokomat-assisted, therapist-assisted BWSTT, or hybrid assistive limb (HAL) exoskeleton walking on a treadmill in people with incomplete SCI (aggregate N = 1167) and six studies in people with complete SCI (aggregate N = 134) who were within 12 months of incurring their SCI (i.e., the acute/subacute phase).

RAGT + Physical Therapy vs. Physical Therapy

The addition of a BWSTT program to conventional rehabilitation typically improves walking outcomes more than conventional rehabilitation programs alone.

During an 8-week RCT, twice weekly RAGT sessions added to 5 days per week of conventional rehabilitation sessions (twice daily – joint range of motion, stretching, strengthening, and gait training) resulted in improved functional walking significantly more than conventional rehabilitation only (median WISCI II score improvement: 4.0 points vs. 1.5 points; P = 0.011) (Yildirim et al. 2019). Additionally, people in the RAGT group improved their functional independence significantly more than those in the conventional rehabilitation only group (median FIM score improvement: 16.0 points vs. 10.0 points; P = 0.022). Both groups improved their functional walking and independence, but the RAGT improved significantly more.

Similarly, Shin et al (2014) found that the RAGT group showed significantly greater gains in functional walking than those in the standard rehabilitation program (median WISCI II score: RAGT: from 3 to 11 vs. Controls: 4 to 9; P =0.01). Members of both groups improved in other walking outcomes, like LEMS and SCIM-III mobility scores, but the only significant difference between the two groups was on functional walking. Alcobendas-Maestro et al. (2012) also found that a Lokomat treatment showed statistically significant improvements vs. conventional treatment in functional walking (WISCI II scores: 16 vs. 9), walking distance (6MWT: 169.4 m vs. 91.3 m), lower limb strength (LEMS: 40 vs. 35) and functional independence (FIM-L: 10 vs. 7).

Conversely, Çinar et al. (2021) found no significant differences between the RAGT group and conventional physical therapy groups in pre- and post-treatment FIM and WISCI II change scores.

RAGT vs. OGT (With or Without Physical Therapy)

Studies that compared RAGT to OGT in people with acute SCI are inconclusive as to whether RAGT or OGT is superior. Nam et al. (2017) performed a meta-analysis, pooling the studies where RAGT was compared directly to OGT in people with acute SCI (only 3 trials; N=211 qualified). The RAGT groups improved significantly more than the OGT groups on a few outcomes: distance walked (pooled mean difference 45.05m; P=0.005), leg strength (2.54 points on LEMS; P=0.04), and in functional/walking independence (0.5 on WISCI-II or FIM-L; P=0.04). Walking speed tended to be higher in RAGT groups than OGT groups but the differences were not significant (pooled mean difference 0.08 m/s).

In one of the highest quality RCTs we found, Dobkin et al. (2006; n=117) provided 12 weeks of equal time of BWSTT or OGT and found no differences in FIM-L scores or in walking speed; in fact, these two variables in both groups improved roughly in parallel over the course of the intervention. One smaller RCT (Hornby et al. 2005a; n = 30) similarly found that there were no differences in motor (LEMS) or functional recovery (FIM-L sub-score or WISCI II score) between those who trained overground, with BWSTT, or with robotic-assisted treadmill training.

Some Better Results in Acute/Subacute SCI

Dobkin et al. (2006) found that participants who entered walking training earlier (< 4 weeks post-injury) had greater gains in walking speeds and endurance post-training, particularly for participants who improved their AIS classification within 4-6 works post-injury. A case-control study by Zieracks et al. (2021) found that 6MWT (performed without the exoskeleton), WISCI II scores and LEMS improved more in acute patients than in chronic patients. Authors have suggested that greater walking improvements during acute/subacute phase could be accounted for by being earlier in the process of regaining function (Dobkin et al. 2006).

Level of Injury Seems to be the Biggest Predictor

Dobkin et al. (2006) reported that the amount of function and movement that the person has before starting training is an important indicator of locomotor recovery. Among the participants who were initially classified as AIS B, those who improved to AIS C within 8 weeks post-injury showed improved walking function while those who remained as AIS B did not (Dobkin et al. 2006). Additionally, 15% of their participants classified as ASIA B, 40% as ASIA C, and 75% as ASIA D at the time of admission were able to walk 150 supervised and at a better level of function at discharge. Dobkin et al. (2006) also found that people classified as ASIA C were significantly more likely than people classified as ASIA B to walk independently (P = 0.001).

In another RCT, Dobkin et al. (2007) confirmed that level of injury/AIS classification is an important variable predicting walking ability. After 12 weeks of BWSTT vs. OGT, < 10% of AIS B, 92% of AIS C and 100% of AIS D notably improved their walking function. Based on these results, they recommend that future trials may reduce the number needed to treat by entering patients with FIM-L < 4 at > 8 weeks after onset if still graded ASIA B and at > 12 weeks if still ASIA C (Dobkin et al. 2007).

Robot-assisted rehabilitation may be superior to conventional rehabilitation in people with AIS A SCI, where voluntary movement is limited, and attempting walking presents more of a safety concern (Khande et al. 2024).

How Much? How Long?

In the studies we found in people with acute SCI, walking training varied from 30 minutes, twice per week, for 4 weeks (Shin et al. 2014) to 30-60 minutes, five times per week, for 8-12 weeks (Dobkin et al. 2006; Esclarin-Ruz et al. 2014). A small RCT (n=18) found that people who performed BWSTT training for 50 minutes per session improved their SCIM-mobility scores from entry to discharge more than those who engaged in 25-minute sessions (SCIM-mobility subscores: 50-minute group: 3 to 20; 25-minute group: 4 to 10; no between-groups significance reported) (Wirz et al. 2017).

There is as of yet no consensus on how much, how long, or how often someone with SCI should be engaging in walking training However, there have been enough studies to suggest that an intensive locomotor program is feasible and could be beneficial in patients with acute SCI, assuming that all medical restrictions and precautions are taken into account (Wirz et al. 2017; SCIRE Community, 2017). A reasonable guiding principle is that the specific amount of time spent in walking training should vary based on what other therapies they are engaged in, as well as each person’s level of exercise-induced fatigue (Dobkin et al. 2006).

Conclusions

There is level 1 evidence (from 2 RCTs: Alcobendas-Maestro et al. 2012; Yildirim et al. 2019) that BWSTT is effective in improving ambulatory function compared to conventional rehabilitation.

There is level 1 and level 2 evidence (from 2 RCTs: Dobkin et al. 2006; Hornby et al. 2005a) demonstrating that BWSTT has equivalent effects in walking outcomes when an equivalent amount of overground mobility practice is used in patients with acute/sub-acute SCI.

There is level 1 evidence (from 1 RCT: Wirz et al. 2017) that intensive sessions (walking time per session > 50 min) of Lokomat-assisted BWSTT for 8 weeks could provide more improvement in the SCIM mobility subscores than non-intensive sessions (walking time per session < 25 min) in patients with acute SCI.

There is level 2 evidence (from 1 prospective controlled trial: Çinar et al. 2020) that Lokomat-assisted BWSTT is effective in improving walking ability (WISCI II) in patients with complete and incomplete (without significant differences between both groups) and subacute SCI.

There is level 2 evidence (from 1 prospective controlled trial: Khande et al. 2024) that Lokomat-assisted BWSTT plus conventional therapy provides significantly larger improvements in walking ability (WISCI II), but not in LEMS, in comparison with standing-walking training using KAFOs plus conventional training in participants with complete (AIS A) and acute (mean time since injury: 6 days).

There is level 3 (from 1 case control study: Zieriacks et al. 2021) that BWSTT with the HAL robot exoskeleton provides similar improvements in walking time and distance on the treadmill with the exoskeleton and walking speed without the exoskeleton (10MWT) in patients with acute and chronic SCI; although 6MWT (performed without the exoskeleton), WISCI II and LEMS improved more in the acute subgroup than in the chronic subgroup.