Selective Posterior Rhizotomy in the Dorsal Root Entry Zone for Treatment of Hyperspasticity and Pain in the Hemiplegic Upper Limb

Abstract

Abstract The authors report a series of 16 hemiplegic patients suffering from harmful spasticity in the upper limb and treated with selective posterior rhizotomy (SPR) in the dorsal root entry zone (DREZ). This severe spasticity was associated with irreducible abnormal postures in flexion in 11 cases and painful manifestations in 12. The method was introduced in 1972 on the basis of anatomical studies of the DREZ in humans, in which a topographical segregation of the root afferents, according to their anatomicofunctional destinations, has been shown. It consists of a DREZ microsurgical lesion 1 to 2 mm in depth and directed at a 45° angle, performed ventrolaterally in the posterolateral sulcus of the spinal cord and into the internal part of the Lissauer's tract. The procedure is carried out in each rootlet of the posterior roots considered to be responsible for the harmful spasticity. SPR interrupts selectively the (lateral) nociceptive and (central) myotactic afferent fibers connecting the motor neurons, while sparing most of the (medial) lemniscal fibers and the inhibitory circuitry of Lissauer's tract and the dorsal horn. The results were evaluated after a 1- to 12-year follow-up. There were no deaths and no general complications; in 1 case a loss of motility in the leg ipsilateral to the procedure occurred. The excess of spasticity was slightly diminished (2 cases), markedly reduced (9 cases), or totally abolished (5 cases), making possible an improvement in voluntary movements in 8 patients and at least a good passive mobilization in 7 further case. In 1 case only, a marked tendency for spasticity to return was observed. Of the 12 patients with painful manifestations, 9 were completely relieved and 3 improved. These beneficial effects on both spasticity and pain led to a gain in functional status in 93% of cases. This was achieved without impairing sensation in the upper limb in 8 cases and with its diminution only in the 8 others.