Shunting of the syrinx cavity can be performed using syringoperitoneal, syringopleural, syringosubarachnoid, or ventriculoperitoneal shunts. Most shunting procedures involve laminectomies and duraplasties prior to the insertion of shunts (Figure 3).
Figure 3. Drainage of syrinx followed by shunt insertion. (Elliot, NSJ 2008b)
In all of the studies, no shunting procedure was found to be superior to another. Schaan and Jaksche (2001) in a cohort study assessed the efficacy of syringomyelia treatment in three groups of patients: Group 1 received various shunts only, Group 2 received shunting followed by surgical creation of a pseudomeningocele, and Group 3 was treated with the pseudomeningocele only. The study found improvement in sensory and motor deficits, pain and syringobulbia in all three groups. However, more patients experienced greater pain post-surgery in the shunting only group than the other two groups.
Falci et al. (1999) demonstrated that untethering and shunt tube placement among individuals without prior surgery can significantly improve light touch, pinprick and motor scores. Two case series (Lee et al. 2001; Lee et al. 2000) further examined untethering and shunting treatment in individuals with syringomyelia. In the study by Lee et al. (2001), patients were divided into three groups: untethering only, shunting only, and untethering and shunting. Improvement in motor and sensory functioning was observed in all three groups. In the first group, untethering only, improvement in spasticity was more common; while the shunting only group found gait improvement to be the most common. Furthermore, shunting alone has been reported to significantly improve pain (Hess & Foo 2001; Hida et al. 1994), strength (Hess & Foo 2001), motor function (Hida et al. 1994) and sensation (Hess & Foo 2001; Hida et al. 1994) in patients with syringomyelia. Although, a high rate of shunt failure (50% and 36%) has been reported (Hess & Foo 2001 and Hida et al. 1994, respectively).
One case control study (Ronen et al. 1999) reviewed charts of patients receiving either rehabilitation only or rehabilitation and shunting for syringomyelia. The study found 80% of patients in the shunting and rehabilitation group experienced functional and neurological deterioration, while patients in the rehabilitation group remained either unchanged or improved. One must be careful when drawing conclusions from such a study because allocation to either group was dictated by receiving the treatment, which presumably was given to those patients already deteriorating or those considered at higher risk of doing so.
Ushewokunze et al. (2010) reported a reduction in syrinx size among 21/40 patients and a stabilization of symptoms among 27/40. However, symptoms deteriorated for 13 individuals. In 17 individuals, a second surgical procedure was required to improve deteriorating symptoms. Several adverse events were reported including pain, neurological deficit, infection and CSF leakage.
There is level 2 evidence (from 1 cohort, 1 pre-post, and 5 case series studies; Ushewokenze et al. 2010; Schaan & Jaksche 2001; Falci et al. 1999; Lee et al. 2000; Lee et al. 2001; Hess &Foo 2001; Hida et al. 1994) that shunting improves pain, motor function and sensory loss in some SCI patients with syringomyelia; however, a high rate of shunt failure has been observed.
Shunting of the syrinx cavity improves pain, motor function and sensory loss in some SCI patients post syringomyelia