Rhizotomy

An L5 spinal nerve ligation (SNL) in the rat leads to behavioral signs of mechanical hyperalgesia. Our recent finding that an L5 dorsal root rhizotomy did not alter the mechanical hyperalgesia following an L5 SNL suggests that signals originating from the proximal stump of the injured nerve are not essential. We postulate that Wallerian degeneration of L5 nerve fibers leads to altered properties of adjacent intact nociceptive afferents. To investigate the role of degeneration in sensory versus motor fibers, five injury models were examined concurrently in a blinded fashion. An L5 ganglionectomy produced a selective lesion of sensory fibers. An L5 ventral root rhizotomy produced a selective lesion of motor fibers. The three control lesions included: (1) SNL with L5 dorsal root rhizotomy; (2) L5 dorsal root rhizotomy; and (3) exposure of the L5 roots without transection (sham). Paw withdrawal thresholds to mechanical stimuli were measured at three sites in the rat hindpaw corresponding to the L3, L4, and L5 dermatomes. Both the ganglionectomy and the ventral rhizotomy produced a significant, lasting ($20d) decrease of mechanical withdrawal thresholds that was comparable to that produced by the SNL lesion. The L5 dorsal rhizotomy, by itself, produced a short lasting (#6 d) decrease in thresholds, whereas the sham procedure did not produce a significant change. We propose that interactions between degenerating motor and sensory fibers of the injured nerve and intact afferent fibers of neighboring nerves play a critical role for both initiation and maintenance of mechanical hyperalgesia in neuropathic pain.

Obwohl neurodestruktive Verfahren sehr effektiv in der Behandlung von Schmerzen malignen und nichtmalignen Ursprungs sein können, werden sie heute kaum noch durchgeführt. Dies liegt zum einen daran, dass sie in der Vergangenheit mit einer hohen Komplikationsrate verbunden waren. Diese Komplikationen beinhalteten das Auftreten neuer neurologischer Defizite und -bei entsprechend langer Nachbeobachtungszeit -das Wiederauftreten der früheren Schmerzen oder neuer Schmerzen durch eine Deafferentierung. Zum anderen gelingt es, mit weniger invasiven, z. B. neuromodulatorischen oder nichtinvasiven Verfahren (systemische, orale, transdermale Opioide, Koanalgetika) einen großen Teil dieser Schmerzen befriedigend zu reduzieren. Dennoch bestehen auch heute noch bestimmte, sehr eingeschränkte Indikationen für die Durchführung neurodestruktiver Verfahren.

Las causas de dolor vertebral pueden clasificarse en mecá nicas e inflamatorias. El dolor mecá nico supone el 97% de las causas de dolor vertebral, incluyendo diagnó sticos como el esguince, la degeneració n discal y facetaria, la estenosis de canal, espondilolistesis y las fracturas osteoporó ticas. Las causas no mecá nicas suponen el 1%, incluyendo la patología inflamatoria, infecciosa y tumoral 1 .

Radiofrequency current is simply a tool used for creating discrete thermal lesions in neural pathways in order to interrupt transmission. In pain medicine, radiofrequency lesions have been used to interrupt nociceptive pathways at various sites. This is a palliative treatment not without complications, so its use should be limited to those patients with cancer pain or chronic non-cancer pain for whom conservative non-surgical therapies have been ineective or intolerable. With the development of alternatives such as intrathecal opioid infusion and neuromodulation technologies, the number of patients considered for neuroablative therapy may dwindle. Nevertheless, there is evidence that radiofrequency neurotomy has an important role in the management of trigeminal neuralgia, nerve root avulsion and spinal pain. In this chapter the evidence for ecacy and safety is reviewed and interrogated with special emphasis on the available randomized controlled trails and systematic review.

Background. Detailed anatomical knowledge of the dorsal cervical rootlets and dorsal root entry zones (DREZ) is important for the diagnosis and treatment of cervical myeloradiculopathy and surgical management of pain. There are far fewer micro-anatomical studies of this area than gross anatomical studies. This study presents several anatomical points regarding the dorsal cervical rootlets and dorsal root entry zones.

In this investigation the authors compared impairment and functional outcomes between two groups of children with cerebral palsy (CP): one group underwent selective dorsal rhizotomy (SDR) followed by intensive physical therapy (PT), and the other group underwent the latter only (PT group). Data from an age-matched group of children without disability (nondisabled [ND] group) were also collected. Data pertaining to the 68 children with CP were collected before any intervention and again 8 and 20 months afterwards. Data regarding the 40 children in the ND group were collected in a single session. Although patients in both groups with CP were weaker than those in the ND group, they did have strength gains. Gait speed in the SDR-PT group was slower than that in the ND group preoperatively but not at 20 months postoperatively. Gait speed in the PT group remained slower than that in the ND group. The pre- to postoperative change in the Gross Motor Abilities Estimate score was significantl...

Selective dorsal rhizotomy AIM The aim of this study was to evaluate the long-term effect of selective dorsal rhizotomy (SDR) on the gross motor function of ambulant children with spastic bilateral cerebral palsy (CP), compared with reference centiles.

We evaluated intraoperative electromyographic (EMG) results among 110 pediatric patients with spastic cerebral palsy who underwent selective posterior rhizotomy. We analyzed surgical outcomes for 60 of these patients who returned for follow-up assessment between 4 and 17 months postoperatively. Reduction in muscle tone (resistance to passive movement), increased range of motion and improvements in functional skills were seen at follow-up. To control for possible changes due to development, participation in therapy, or instability of measurements, 30 rhizotomy patients were evaluated twice during a baseline period of several months prior to surgery. No significant changes were found between these two measurement sessions during the baseline control period suggesting that the rhizotomy surgery itself caused the postoperative improvements. These intraoperative EMG monitoring techniques have been adopted at many other centers but variations in specific methods and EMG criteria have deve...

Selective dorsal rhizotomy AIM Information regarding the selection procedure for selective dorsal rhizotomy (SDR) in children with spastic cerebral palsy (CP) is scarce. Therefore, the aim of this study was to summarize the selection criteria for SDR in children with spastic CP.

The primary aim of this prospective cohort study was to evaluate the short-term (1 year) and long-term (mean 6 years) effects of selective dorsal rhizotomy (SDR) on gross motor function and spasticity in ambulatory children with spastic diplegia. Secondary aims were to investigate side effects, additional treatment during follow-up (botulinum toxin type A injections or orthopedic surgery), and parental satisfaction. Thirty-three children who had undergone SDR at a mean age of 6 years and 7 months (± 2 years) were included. There were 7 children at Gross Motor Function Classification System (GMFCS) Level I, 7 at Level II, and 19 at Level III. Gross motor function was assessed with the Gross Motor Function Measure-66 (GMFM-66). Spasticity was measured according to a modified Tardieu scale. Side effects, additional treatment, and parental satisfaction were recorded using a parental questionnaire and medical records. At 1-year follow-up, mean GMFM-66 scores improved significantly by 4.3...

This study was performed to determine which of uninjured lumbar 4 (L4) C-afferents and injured L5 afferents was important for the generation of mechanical hypersensitivity following L5 spinal nerve ligation-and-cut (SNLC, modified spinal nerve ligation) in the rat. The mechanical hypersensitivity established following L5 SNLC was completely abolished 6 weeks after local capsaicin treatment of the sciatic nerve or L4 spinal nerve. At this stage, a substantial number of capsaicin-sensitive C-afferents were eliminated without any loss of A-afferents in the L4 spinal segment, suggesting that the capsaicin-sensitive L4 C-afferents are a major contributor to L5 SNLC-produced mechanical hypersensitivity. The peripheral terminals of L4 C-afferents are active in maintaining mechanical hypersensitivity, even long after L5 SNLC. When capsaicin-sensitive L4 C-afferents were previously eliminated, the induction of L5 SNLC-produced hypersensitivity was partly prevented. Thus, capsaicin-sensitive L4 C-afferents are crucial for the induction and maintenance of mechanical hypersensitivity in the L5 SNLC model. Also, when capsaicinsensitive L4 C-afferents were previously eliminated, L5 SNLC still produced a partial mechanical hypersensitivity for a 1-to 2-week maintenance period with a several-day delay. This mild hypersensitivity was prevented by the previous L5 dorsal rhizotomy, implying an involvement of inputs from injured L5 afferents in the maintenance of hypersensitivity at the earlier stage. The results suggest that uninjured C-afferents, most likely Cpolymodal nociceptors, are necessary for the induction and maintenance of neuropathic pain, and that afferent inputs, presumably from injured Aβ-fibers, also contribute to the maintenance at an earlier stage.

Cerebral palsy Muscle spasticity Gait Oxygen consumption a b s t r a c t Background: One of the treatment option to reduce spasticity in cerebral palsy children is selective dorsal rhizotomy. Several studies have demonstrated short and long term improvements in gait and other activities after rhizotomy but this surgery still remains a controversial procedure and patient outcome indicators measures are not uniform.

Radiofrequency thermocoagulation (RFT) of trigeminal ganglion is a commonly performed percutaneous procedure for the management of trigeminal neuralgia. However, it is not free from potentially life-threatening complications. A case of intracranial hemorrhage following RFT, which was managed conservatively, is reported. The authors suggest that coagulation parameters be normalized and intra-procedural blood pressure controlled while performing this technique. As RFT is carried out as an ambulatory procedure, absence of any intracranial complication must be ascertained clinically before the patient is discharged.

Selective dorsal rhizotomy AIM Information regarding the selection procedure for selective dorsal rhizotomy (SDR) in children with spastic cerebral palsy (CP) is scarce. Therefore, the aim of this study was to summarize the selection criteria for SDR in children with spastic CP.

Posterior rhizotomy for relief of spasticity first was reported experimentally by Sherrington in 1898 and later in 1908 when Foerster introduced it into clinical practice. Foerster credited Monro with performing similar work as early as 1904. At that time, Foerster proposed for the treatment of upper limb spasticity dorsal rhizotomy of C4 to T2 preserving C6, or alternatively partial dorsal rhizotomy of all these roots. Foerster stated that the effect of posterior rhizotomy was likely to be better in the lower limb than in the upper limb . In the last decade, major interest in this topic has emerged and posterior rhizotomy now is frequently used to treat lower limb spasticity . The literature has less to say about the treatment of upper limb spasticity by cervical dorsal rhizotomy.

OBJECTIVE: The objective of this study was to evaluate the effectiveness of percutaneous, controlled radiofrequency trigeminal rhizotomy (RF-TR). The outcome of 1600 patients with idiopathic trigeminal neuralgia after RF-TR was analyzed after a follow-up period of 1 to 25 years. METHODS: A total of 1600 patients with idiopathic trigeminal neuralgia underwent 2138 percutaneous radiofrequency rhizotomy procedures between 1974 and 1999. Sixty-seven patients had bilateral idiopathic trigeminal neuralgia, and 36 of them were treated with bilateral RF-TR; 1216 patients (76%) were successfully managed with a single procedure, and the remainder were treated with multiple procedures. Benzodiazepines and narcotic analgesics were used for anesthesia because patient cooperation during the procedures was essential so that the physician could create selective, controlled lesions. RESULTS: The average follow-up time was 68.1 ؎ 66.4 months (range, 12-300 mo). Acute pain relief was accomplished in 97.6% of patients. Complete pain relief was achieved at 5 years in 57.7% of the patients who underwent a single procedure. Pain relief was reported in 92% of patients with a single procedure or with multiple procedures 5 years after the first rhizotomy was performed. At 10-year follow-up, 52.3% of the patients who underwent a single procedure and 94.2% of the patients who underwent multiple procedures had experienced pain relief; at 20-year follow-up, 41 and 100% of these patients, respectively, had experienced pain relief. No mortalities occurred. After the first procedure was performed, early pain recurrence (<6 mo) was observed in 123 patients (7.7%) and late pain recurrence was observed in 278 patients (17.4%). Complications included diminished corneal reflex in 91 patients (5.7%), masseter weakness and paralysis in 66 (4.1%), dysesthesia in 16 (1%), anesthesia dolorosa in 12 (0.8%), keratitis in 10 (0.6%), and transient paralysis of Cranial Nerves III and VI in 12 (0.8%). Permanent Cranial Nerve VI palsy was observed in two patients, cerebrospinal fluid leakage in two, carotid-cavernous fistula in one, and aseptic meningitis in one. CONCLUSION: Percutaneous, controlled RF-TR represents a minimally invasive, low-risk technique with a high rate of efficacy. The procedure may safely be repeated if pain recurs. (Neurosurgery 48:524-534, 2001)

An intradural somatic-to-autonomic anastomosis, or Xiao procedure, has been described to create a &quot;skin-CNS-bladder&quot; reflex that improves bladder and bowel function in patients with neurogenic bladder and bowel dysfunction. The authors present their experience with a 10-year-old boy with chronic neurogenic bladder and bowel dysfunction related to spinal cord injury who underwent the Xiao procedure. After undergoing a left L-5 ventral root to left S2-3 intradural anastomosis, the patient reported that his bladder and bowel dysfunction improved between 6 and 12 months. Two years after the procedure, however, he reported that there was no change in his bladder or bowel dysfunction as compared with his condition prior to the procedure. Frequent, systematic multidisciplinary evaluations produced conflicting data. Electrophysiological and histological evaluation of the previously performed anastomosis during surgical reexploration 3 years after the Xiao procedure revealed that t...

Spinal cord sensory synapses are glutamatergic, but previous studies have found a great diversity in synaptic vesicle structure and have suggested additional neurotransmitters. The identification of several vesicular glutamate transporters (VGLUTs) similarly revealed an unexpected molecular diversity among glutamate-containing terminals. Therefore, we quantitatively investigated VGLUT1 and VGLUT2 content in the central synapses of spinal sensory afferents by using confocal and electron microscopy immunocytochemistry. VGLUT1 localization (most abundant in LIII/LIV and medial LV) is consistent with an origin from cutaneous and muscle mechanoreceptors. Accordingly, most VGLUT1 immunoreactivity disappeared after rhizotomy and colocalized with markers of cutaneous (SSEA4) and muscle (parvalbumin) mechanoreceptors. With postembedding colloidal gold, intense VGLUT1 immunoreactivity was found in 88 -95% (depending on the antibody used) of C II dorsal horn glomerular terminals and in large ventral horn synapses receiving axoaxonic contacts. VGLUT1 partially colocalized with CGRP in some large dense-core vesicles (LDCVs). However, immunostaining in neuropeptidergic afferents was inconsistent between VGLUT1 antibodies and rather weak with light microscopy. VGLUT2 immunoreactivity was widespread in all spinal cord laminae, with higher intensities in LII and lateral LV, complementing VGLUT1 distribution. VGLUT2 immunoreactivity did not change after rhizotomy, suggesting a preferential intrinsic origin. However, weak VGLUT2 immunoreactivity was detectable in primary sensory nociceptors expressing lectin (GSA-IB4) binding and in 83-90% of C I glomerular terminals in LII. Additional weak VGLUT2 immunoreactivity was found over the small clear vesicles of LDCV-containing afferents and in 50 -60% of C II terminals in LIII. These results indicate a diversity of VGLUT isoform combinations expressed in different spinal primary afferents.

In children with pulmonary atresia not amenable to initial complete correction, antegrade pulmonary blood flow can be established with surgical right ventricular outflow tract (RVOT) patch enlargement. An 11-year experience with RVOT transannular patch (TAP) augmentation without the use of cardiopulmonary bypass (off-pump) is reported. From March 1993 to October 2004, off-pump surgical RVOT enlargement with a TAP was attempted in all patients in whom a concurrent procedure that required bypass was not required. The procedure was performed with cardiopulmonary bypass standby. Twenty-two consecutive patients in whom this procedure was attempted were reviewed. Twenty of 22 patients tolerated off-pump TAP placement. In 2 patients with ductal-dependent pulmonary blood flow, off-pump TAP placement was not tolerated. Adequate antegrade pulmonary blood flow was achieved in all patients without operative mortalities or complications. There was one death in the postoperative period from myocardial ischemia secondary to right ventricular-dependent coronary circulation. Transannular RVOT patch augmentation can be performed safely and effectively without cardiopulmonary bypass.

In the recent years new technology has led to the development of a bewildering array of imaging procedures. Yet, conventional radiography remains one of the most used tools to diagnose and to aid procedural interventions. Fluoroscopy guidance facilitates targeted drug delivery or radiofrequency directly to the area of pathology, a benefit that has to be balanced against the risks of radiation exposure. In this prospective observational survey of routine practice, dose area product (DAP) and screening time (ST) were recorded in 127 consecutive patients undergoing fluoroscopically guided spinal procedures along with other probable measures of potentially greater radiation exposure such as weight, type of spinal pathology, the ease of recognition of the anatomical landmarks, and the radiographic quality of the image in terms of contrast and graininess. The mean ST was 34±27 seconds (range, 3 to 218 seconds), the mean DAP was 1.18±1.08 Gy cm(2) (range, 0.023 to 6.82 seconds). A correlat...

A comparative histological analysis of two models of nerve root avulsion injury in the adult rat Aims: This study has investigated the reliability of the artificial surgical model dorsal root rhizotomy (DRR), to the surgical tearing of the roots, avulsion, that occurs clinically. Root avulsion of the limb nerves is common in high-impact motor vehicle accidents and results in paraesthesia, paralysis and intractable pain. Limited treatment options are largely due to a lack of basic research on underlying mechanisms, and few animal models. We assess this limitation by histologically assessing the spatial and temporal injury profile of dorsal root avulsion (DRA) and DRR within the spinal cord. Methods: Rats underwent DRR, DRA or sham surgery to the L3-L6 dorsal roots unilaterally. At 1, 2, 14, and 28 days post injury, immunohistochemical density staining was used to characterize the progression of spinal cord trauma. Neuronal (NeuN) and vascular degeneration (RECA-1), inflammatory infiltrate (ED1, anti-neutrophil), gliosis (Iba1, GFAP) and apoptosis (TUNEL) were assessed. Results: Unilateral DRA produced a prolonged and bilateral glial and inflammatory response, and vascular degeneration compared to transient and unilateral effects after DRR. Transsynaptic neurodegeneration after DRA was greater than after DRR, and progressed across 28 days coinciding with gliosis and macrophage infiltration. Conclusions: Rhizotomy leads to a milder representation of the spinal cord trauma that occurs after 'true' avulsion injury. We recommend DRA be used in the future to more reliably model clinical avulsion injury. Avulsion is an injury with a chronic profile of degenerative and inflammatory progression, and this theoretically provides a window of clinical therapeutic opportunity in treatment of secondary trauma progression.

A peripheral nerve lesion induces sprouting of primary afferents from dorsal root ganglion (DRG) neurons into lamina II of the dorsal horn. Modi®cations of the environment in consequence to the axotomy provide an extrinsic stimulus. A potential neuron-intrinsic factor that may permit axonal sprouting is microtubule-associated protein 1B (MAP1B) in a speci®c phosphorylated form (MAP1B-P), restricted to growing or regenerating axons. We show here that both in rat and mouse, a sciatic nerve cut is rapidly followed by the appearance of MAP1B-P expression in lamina II, increasing to a maximum between 8 and 15 days, and diminishing after three months. Evidence is provided that sprouting and induction of MAP1B-P expression after peripheral injury are phenomena concerning essentially myelinated axons. This is in accordance with in situ hybridization data showing especially high MAP1B-mRNA levels in large size DRG neurons that give rise to myelinated ®bers. We then employed a second lesion model, multiple rhizotomy with one spared root. In this case, unmyelinated CGRP expressing ®bers do indeed sprout, but coexpression of MAP1B-P and CGRP is never observed in lamina II. Finally, because a characteristic of myelinated ®bers is their high content in neuro®lament protein heavy subunit (NF-H), we used NF-H-LacZ transgenic mice to verify that MAP1B-P induction and central sprouting were not affected by perturbing the axonal organization of neuro®laments. We conclude that MAP1B-P is well suited as a rapidly expressed, axon-intrinsic marker associated with plasticity of myelinated ®bers.

This study investigated the effects of spasticity in the hamstrings and quadriceps muscles on gait parameters including temporal spatial measures, knee position, excursion and angular velocity in 25 children with spastic diplegic cerebral palsy (CP) as compared to 17 agematched peers. While subjects were instructed to relax, an isokinetic device alternately flexed and extended the left knee at one of the three constant velocities 308/s, 608/s and 1208/s, while surface electromyography (EMG) electrodes over the biceps femoris and the rectus femoris recorded muscle activity. Patients then participated in 3D gait analysis at a self-selected speed. Results showed that, those with CP who exhibited heightened stretch responses (spasticity) in both muscles, had significantly slower knee angular velocities during the swing phase of gait as compared to those with and without CP who did not exhibit stretch responses at the joint and the tested speeds. The measured amount (torque) of the resistance to passive flexion or extension was not related to gait parameters in subjects with CP; however, the rate of change in resistance torque per unit angle change (stiffness) at the fastest test speed of 1208/s showed weak to moderate relationships with knee angular velocity and motion during gait. For the subset of seven patients with CP who subsequently underwent a selective dorsal rhizotomy, knee angular extension and flexion velocity increased post-operatively, suggesting some degree of causality between spasticity and movement speed. # . Mean stiffness in the hamstrings muscles, calculated as the slope of the torque  angle curve, at the isokinetic velocity of 1208/s plotted for the subgoups with hamstring + quadriceps spasticity, hamstring spasticity only, the CP group with no hamstring or quadriceps spasticity, and the non-CP comparison group.

O nce the diagnosis of essential TN is made, medical therapy becomes the initial approach in most cases. However, medical therapy in many patients is either unsuccessful or they are unable to tolerate it, and these patients eventually require surgical intervention. In the past, surgery typically involved MVD or one of several percutaneous ablative procedures. 14 Although often associated with initial pain relief, all those surgical procedures have variable but definitive rates of recurrence and morbidity. The use of SRS has been advocated as a minimally invasive alternative surgical approach for treating TN. Stereotactic irradiation of the trigeminal ganglion was first reported by Leksell. 10 More recently, several authors have reported their initial results with radiosurgery in which high-resolution image guidance was used.