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Untethering

Spinal cord tethering is commonly seen in patients with syringomyelia. A tethered spinal cord occurs when scar tissue forms and holds the spinal cord to its surrounding soft tissue membrane and dura. It has significant effects on spinal cord movement, CSF flow and extracellular fluid flow resulting in mobility issues and intramedullary pressure changes when exerting certain movements (Klekamp & Samii 2002). Untethering of the spinal cord is used to prevent or revise neurological or orthopedic sequelae.

Table 2 Untethering

Author Year

Country
Research Design

Score
Total Sample Size

MethodsOutcome
Falci et al. 2009

USA

Pre-Post

N=362

Population: Mean age: 40.5 yr; Level of injury: C6=163, C6-T1=83, T1=116; Level of severity: AIS A=229, B=36, C=41, D=54, E=2.

Intervention: Surgical treatment for spinal cord untethering.

Outcome Measures: Asia Impairment Scale (AIS) sensory and motor scores, Sensory and motor changes, Subjective report of changes post-surgery.

1.     Sixty percent of the patients found an improvement in spasticity, 77% found an improvement in hyperhidrosis and 47% reported an improvement in neuropathic pain.

2.     Most patients (86.5%) required only one surgery.

3.     Progressive myelopathy regarding sensory and motor functions was arrested for an average of 3.3-3.4 yr post-surgery.

4.     89% of patients reported an arrest in loss of sensory and/or motor function post-surgery.

5.     Return of function was reported in 46% of the patients.

Lee et al. 2001

USA

Case Series

N=45

Population: Mean age: 45.6 yr; Gender: males=30, females=15.

Intervention: Records of patients who underwent surgical treatment for posttraumatic syringomyelia were assessed. Patients were divided into three groups: Group 1 underwent untethering only, Group 2 underwent shunting only, and Group 3 underwent both untethering and shunting. Patients were followed up to assess treatment efficacy.

Outcome Measures: Improvement in symptoms, Magnetic Resonance Imaging (MRI), Complications.

1.     There was no significant difference in outcomes between groups.

2.     Patients in the surgical untethering group:

a.     Demonstrated improvement in motor and spasticity symptoms in the majority of patients (60% and 58%, respectively).

b.     Experienced 1 treatment failure and 2 complications.

c.      Revealed cyst re-accumulation at 1 yr follow-up.

3.     The shunt only group experienced one complication and three treatment failures; 60% of patients in this group experienced improvement in gait followed by sensory (57%) and motor (54%).

4.     Among those who underwent both untethering and shunting, 33% had clinical recurrence, one experienced CSF leak, and 50% showed improvement in motor symptoms.

Lee et al. 2000

USA

Case Series

N=34

Population: Mean age: 43.2 yr; Gender: males=23, females=11.

Intervention: Records of patients who underwent surgical treatment for posttraumatic syringomyelia were assessed. Patients underwent laminectomies and a syringosubarachnoid shunt was inserted. Patients were divided into three groups: Group 1 underwent untethering only, Group 2 underwent shunting only, and Group 3 underwent both untethering and shunting. Patients were followed up to assess treatment efficacy.

Outcome Measures: Improvement in symptoms, Complications.

1.     At follow-up (>1 yr), 26 patients had resolution of one or more of their pre-operative symptoms; two patients experienced deterioration of motor function.

2.     A decrease in spasticity was the most common improvement in patients who underwent untethering only (67%), followed by motor functioning (57%) and sensory loss (50%); this group experienced one treatment failure and two complications.

3.     Improvement in gait was seen most frequently in the shunt only procedure group (60%), followed by motor (50%) and sensory loss (50%); in this group, two treatment failures and two complications occurred.

4.     Patients who underwent untethering and shunt procedures did not experience clinical reoccurrence; motor (67%) and gait (50%) improved in patients in this group.

Falci et al. 1999

USA

Case Series

N=59

Population: Mean age: 26 yr; Gender: males=49, females=10; Level of severity: AIS A=53, B=1, C=4, D=1.

Intervention: All patients underwent spinal untethering and if a spinal cyst was present a lumbo-peritoneal shunt tube was placed along the length of the cyst.

Outcome Measures: Pinprick, Motor and light touch scores, Magnetic Resonance Imaging (MRI) findings, Somatosensory evoked potentials.

1.     Participants with no previous surgery showed a significant increase in light touch (+2.38), pinprick (+3.88) and motor scores (+1.47) post-surgery.

2.     Participants who had previous surgery had a decrease in touch, pinprick and motor score, although it was minimal (0.7, 0.8, and 0.5, respectively).

3.     At 2 wk post-surgery, MRI showed decreased cyst size or complete collapse.

4.     Somatosensory evoked potentials were improved in amplitude compared to baseline; latency of 2 milliseconds or greater was observed in 27 patients.

Discussion

In a pre-post trial, Falci et al. (2009) reported that spinal cord untethering resulted in improvement in neuropathic pain, sensory and motor functions. Falci et al. (1999) found untethering and shunt tube placement resulted in a significant improvement in light touch, pinprick and motor scores in SCI patients without previous syringomyelia surgery. Two case series (Lee et al. 2001; Lee et al. 2000) assessed the result of untethering only, shunting only, and untethering and shunting in a group of SCI individuals with syringomyelia. Both studies found that more patients in the untethering only group had improved spasticity than patients in the other groups. Motor function and sensory loss improvement was common in all three groups. However, the shunting group only demonstrated more improvement in gait than the untethering group.

Conclusions

There is level 4 evidence (from one pre-post and three case series studies; Falci et al. 2009; Falci et al. 1999; Lee et al. 2000; Lee et al. 2001) that untethering improves motor and sensory loss.

There is level 4 evidence (from two case series studies; Lee et al. 2000; Lee et al. 2001) that untethering improves spasticity in more patients with syringomyelia than shunting.

Untethering improves spasticity and motor and sensory loss post SCI-related syringomyelia.