A novel animal model of underactive bladder: analysis of lower urinary tract function in a rat lumbar canal stenosis model.

AIMS: An animal model of neurogenic underactive bladder (UAB) has not been established. It was reported that a rat lumbar spinal canal stenosis (LCS) model created by cauda equina compression manifested intermittent claudication and allodynia. In this study, we examined the lower urinary tract function of the rat LCS model. METHODS: One small hole was drilled at the fifth lumbar vertebral arch (sham), and a rectangular piece of silicone rubber was inserted into the L5-L6 epidural space (LCS). Before and after surgery, a metabolic cage study was performed. After surgery, awake cystometry (CMG) and an in vitro muscle strip study were performed. Bladder morphology was evaluated by hematoxylin and eosin staining. RESULTS: The LCS rats showed a significant decrease in voided volume and a significant increase in postvoid residual volume and residual urine rate compared with Sham rats. CMG showed that the postvoid residual urine volume and numbers of non-voiding contractions significantly increased, while the voided volume, threshold pressure, and maximum intravesical pressure during voiding significantly decreased. There were no significant differences between sham and LCS rats in response to carbachol. In contrast, there was a significant increase in response to field stimulation, especially at lower frequencies, in LCS rats. LCS rats showed no obvious difference in detrusor morphology. CONCLUSIONS: This rat model requires a relatively simple surgical procedure and has characteristics of neurogenic UAB. It seems to be useful in the pathophysiological elucidation of UAB and might have potential for assessment of pharmacotherapy of UAB.

The clinical study of repairing cauda equina fibres with fibrin glue after lumbar fracture and dislocation.

STUDY DESIGN: A retrospective study. OBJECTIVES: To study the outcome of repair of cauda equina fibres with fibrin glue after lumbar fracture and/or dislocation. METHODS: Seven acute cases and one chronic case of L2 or L3 fracture and/or dislocation complicated with complete cauda equina injury were selected. Sural nerve or ventral roots of injured cauda equina were chosen to repair the motor cauda equina fibres with fibrin glue after open reduction and internal fixation of the unstable vertebrae. The functional recovery after surgery was observed. RESULTS: Recovery of the strength of thigh muscles (iliopsoas, quadriceps femoris, gluteus maximus, adductors) was observed in all seven acutely injured patients (t=3.74, P<0.05), but not in the chronic one. Neither recovery of leg muscles nor sensation of the lower extremities was observed in any case. CONCLUSIONS: The cauda equina ventral roots injured after lumbar fracture and/or dislocation can be repaired with fibrin glue and motor recovery is expected.

Cauda equina biopsy as a tool in the diagnosis of malignant tumors.

The prevalence of malignant lymphoma is increasing. With the advent of novel therapeutic approaches, the distinct pathology of each type of malignant lymphoma is used to tailor its treatment for the most effective outcome. Therefore, analysis of the malignant cell pathophysiology within the cauda equina is important to devising a treatment strategy. In some cases, the tumor only invades the cauda equina. Composed of an uninterrupted bundle of nerve fibers, the cauda equina is more complex than the brain parenchyma; hence, the method for performing a biopsy of the cauda equina is relatively more challenging and requires improvement. The appropriate surgical procedure to confirm the posterior ramus, which consists of sensory roots, is mandatory. In the lumbar region, the denticulate ligaments that distinguish between the motor and sensory nerve roots do not exist. Microsurgical techniques and neurophysiological monitoring can aid with removal of posterior roots and allow for the reliable performance of a cauda equina biopsy. First, we determined where the spinal root pierces the dura mater, and then we performed electromyography. We performed cauda equina biopsy with this method for patients with malignant lymphoma and reviewed the efficacy of this procedure. This strategy prevented postoperative neurological impairments and provided detailed information to ensure optimal adjuvant therapy. Based on advances in personalized therapies for malignant tumors, opportunities for cauda equina biopsy are increasing. Our method using both morphological feature observation and neurophysiological monitoring may contribute to successful biopsy of the cauda equina.

Acellular Cauda Equina Allograft as Main Material Combined with Biodegradable Chitin Conduit for Regeneration of Long-Distance Sciatic Nerve Defect in Rats.

Autologous nerve grafting (ANG), the gold standard treatment for peripheral nerve defects, still has many restrictions. In this study, the acellular cauda equina allograft (ACEA), which consists of biodegradable chitin conduit and acellular cauda equina, is developed. The cauda equina is able to complete decellularization more quickly and efficiently than sciatic nerves under the same conditions, and it is able to reserve more basal lamina tube. In vitro, ACEA shows superior guidance capacity for the regeneration of axons and migration of Schwann cells compared to acellular sciatic nerve allograft (ASNA) in dorsal root ganglion culture. In vivo, ACEA is used to bridge 15 mm long-distance defects in rat sciatic nerves. On day 21 after transplantation, the regenerative distance of neurofilaments in the grafting segment is not significantly different between the ACEA and ANG groups. At week 12, ACEA group shows better sciatic nerve repair than chitin conduit only and ASNA groups, and the effect is similar to that in the ANG group as determined by gait analysis, neural electrophysiological, and histological analyses. The above results suggest that the ACEA has the potential to become a new biological material as a replacement for autografting in the treatment of long-distance nerve defects.

Effective cauda equina decompression in two siblings with Charcot-Marie-Tooth disease type 1B.

Two siblings with Charcot-Marie-Tooth (CMT) 1B due to a c.517G>C (p.Gly173Arg) mutation in the MPZ gene both developed an acute cauda syndrome with unbearable back pain radiating to both legs, progressive muscle weakness of the legs, and saddle hypesthesia with fecal and urinary incontinence. MRI showed in both patients a lumbar spinal canal totally filled with hypertrophic caudal nerve roots. We performed acute decompression. Postoperatively, in both patients, the back pain resolved immediately, there was a significant improvement of both the paresis of the legs and the hypesthesia, and there was a full return of continence. There was no recurrence of acute symptoms during respectively 19 years and 1.5 years of follow-up. We conclude that in patients with CMT and a related cauda syndrome because of hypertrophic caudal nerve roots, acute decompression can be an effective and safe treatment with long-term efficacy.

[A new surgical treatment for syringomyelia, scoliosis, Arnold-Chiari malformation, kinking of the brainstem, odontoid recess, idiopathic basilar impression and platybasia]. / Nuevo tratamiento quirúrgico para la siringomielia, la escoliosis, la malformación de Arnold-Chiari, el kinking del tronco cerebral, el retroceso odontoideo, la impresión basilar y la platibasia idiopáticas.

INTRODUCTION: Based on medullary traction as responsible for idiopathic syringomyelia (SMI), idiopathic scoliosis (ESCID), Arnold Chiari malformation (ARCH), platybasia (PTB), basilar impression (IMB), odontoid recess (RTO) kinking of the brain stem (KTC) and considering the medullary traction to be transmitted by the filum terminale (FT), a surgical technique for the section of FT (SFT) is described in three cases of SMI, one of ESCID, and one of ARCH with no lumbar dysraphia. MATERIAL AND METHODS: A 34-year-old woman with cervico-brachialgias, paresthesias, bilateral babinski and a centro-medullary cavity C3-C7. A 26-year-old male with cervico-brachialgias, hypoestesia in left hemybody, and cervicobulbar cavity. A 19-year-old female with ESCID since the age of 14th, with episodes of reacuting, and 38o of dorsolumbar curvature. A 67-year-old woman with intense headache, hypoesthesia of the hands, paraparesia and ARCH. A 23-year-old man with marked tetraparesia, bilateral babinski, anesthesia of both legs, SMI, ESCID, ARCH and hydrocephaly. RESULTS: After SFT: in the SMIs the thermo-algesic, disesthetic and algic dissociation disappeared. In ESCID there was a reduction to 31o in the curvature in nine months. On ARCH the headaches ceased and there was recovery of touch and paraparesia. CONCLUSIONS: SFT is a useful etiological treatment for SMI, ESCID, ARCH. Also, in ESCID it is possible to avoid stress on the medulla due to its surgical reduction.

Implantation of cauda equina nerve roots through a biodegradable scaffold at the conus medullaris in rat.

BACKGROUND CONTEXT: Traumatic injuries occurring at the conus medullaris of the spinal cord cause permanent damage both to the central nervous system and to the cauda equina nerve roots. PURPOSE: This proof-of-concept study was to determine whether implanting the nerve roots into a biodegradable scaffold would improve regeneration after injury. METHODS: All experimental works involving rats were performed according to the approved guidelines by the Mayo Clinic Institutional Animal Care and Use Committee. Surgical procedures were performed on 32 Sprague-Dawley rats. Four ventral cauda equina nerve roots were reimplanted either directly into the ventral cord stump or through a poly(lactic-co-glycolic acid) (PLGA) scaffold. These experimental groups were compared with a control group in which the nerves were inserted into a muscle fascia barrier that was placed between the spinal cord and the nerve roots. Animals were sacrificed at 4 weeks. RESULTS: There was no difference in motor neuron counts in the spinal cord rostral to the injury in all treatment groups, implying equal potential for the regeneration into implanted nerve roots. One-way analysis of variance testing, with Tukey post hoc test, showed a statistically significant improvement in axon regeneration through the injury in the PLGA scaffold treatment group compared with the control (p<.05, scaffold n=11, control n=11). CONCLUSIONS: This pilot study demonstrated that a PLGA scaffold improved regeneration of axons into peripheral nerve roots. However, the number of regenerating axons observed was limited and did not lead to functional recovery. Future experiments will employ a different scaffold material and possible growth factors or enzymes to increase axon populations.

Cauda equina compression by hydrogel dural sealant after a laminotomy and discectomy: case report.

STUDY DESIGN: The authors present a case of cauda equina compression after laminotomy and discectomy where incidental durotomy was managed with the application of hydrogel sealant. The patient reported return of radicular symptoms on the first postoperative day, and deterioration to early cauda equina syndrome after bending on the sixth day. OBJECTIVE: To demonstrate that in addition to its recognized volume expansion properties, that the product has the ability to migrate and produce symptoms remote from where it was inserted. SUMMARY OF BACKGROUND DATA: The physical properties of DuraSeal (Confluent Surgical, Waltham, MA), a hydrogel dural sealant, make it an effective adjunct to dural closure. Its volume expansion has been associated with neural compression after posterior fossa decompression. We have found no reported migration of this product. METHODS: Sequential postoperative imaging shows swelling and migration of the hydrogel into spinal canal with resultant compression. Exploration on postoperative day 10 revealed sealant causing cauda equina compression proximal to the site of the durotomy. CONCLUSION: The authors recommend that in addition to caution regarding its potential mass effect, that cognizance be taken of the product's potential to migrate and result in symptoms at a distant site.