Microsurgical Anatomy of Lumbosacral Nerve Rootlets for Highly Selective Rhizotomy in Chronic Spinal Cord Injury

Abstract

It is known that selective sacral roots rhizotomy is effective for relieving the neurogenic bladder associated with spinal cord injury. The goal of this study is to review the surgical anatomy of the lumbosacral nerve rootlets and to provide some morphological bases for highly selective sacral roots rhizotomy. Spinal cord dissections were performed on five cadavers under surgical microscope. At each spinal cord segment, we recorded the number, diameter and length of the rootlets, subbundles and bundles from the L1 to S2 spinal segments, and the length of the dorsal/ventral root entry zone. Peripheral nervous system myelin was examined by immunohistochemistry. We found: (1) the ventral or the dorsal root of the lumbosacral segment of the spinal cord was divided into one to three nerve bundles and each bundle was subdivided into one to three subbundles. Each subbundle further gave out two to three rootlets connected with the spinal cord; (2) there were no significant differences in the number of rootlets within the L1 to S2 segments, but the size of rootlets and the length of nerve roots varied (P < 0.05); and (3) the more myelinated fibers a rootlet contained, the larger transection area it had. The area of peripheral nervous system myelin positive cells and the total area of rootlets were correlated (P < 0.001). Thus, during highly selective sacral roots rhizotomy, the ventral and dorsal roots can be divided into several bundles of rootlets, and we could initially distinct the rootlets by their diameters. Anat Rec, 293:2123Rec, 293: -2128Rec, 293: , 2010. V V C 2010 Wiley-Liss, Inc.Key words: microsurgical anatomy; lumbosacral nerve rootlet; highly selective sacral rootlets rhizotomy; spinal cord injuryInjuries to the central nervous system in humans are associated with a low degree of neurological recovery and, in most cases, lifelong debilitation. Spinal cord injury (SCI) can result not only in paraplegia or quadriplegia but also in loss of urinary and defecatory control as well as alteration of sexual function (Pedersen, 1983;

Microsurgical anatomy of the dorsal thoracic rootlets and dorsal root entry zones

“…In fact, the most frequent complications of DREZ surgery at the thoracic level are ipsilateral leg weakness and a likely reduction in bladder reflexes [14]. At each spinal segment, a few rootlets emerge to give rise to a dorsal root; the number of dorsal rootlets varies at each spinal cord segment [4,7,17,18]. Most thoracic segments give rise to 3-4 dorsal rootlets, which are fewer than those seen at the cervical and lumbosacral segments.…”

“…The dorsal rootlet entry into the posterolateral sulcus varies in accordance with the levels of the spinal cord. Although these relationships have been studied in detail for cervical, lumbar, and sacral spinal segments, such information is not available for thoracic segments [4,6,7,17,18]. Though less frequent, thoracic DREZ surgeries are performed in cases of postherpetic neuralgia, spasticity and/or pain after spinal cord injury, and pain due to malignant invasions of the thorax and abdominal wall [2,15].…”

The diameters and number of nerve fibers in spinal nerve roots

“…Typically, a number of rootlets originate from the corresponding level of spinal cord, and then they are aggregated gradually to form nerve sub-bundles, bundles, and finally a nerve root. 7 As shown in Fig. 1 (Parts A, B, and C), the ventral roots adjacent to the dura usually consisted of only one nerve bundle while most dorsal roots normally comprised several nerve bundles.…”

Clinical anatomy and significance of the thoracic intervertebral foramen: A cadaveric study and review of the literature

“…[61516] Kirazli et al . found that the average number of dorsal thoracic rootlets is 6.6 ± 0.8, which is higher than what Sindou found.…”

“…[3334] However, others reports suggest that there is side-independence of the spinal dimensions. [163536] In terms of sexual dimorphism, Rühli et al . found that IVF width is greater in females than males.…”