Congenital kyphosis in myelomeningocele. The effect of cordotomy on bladder function.
To determine the effect of cordotomy on the function of the bladder during surgical correction of congenital kyphosis in myelomeningocele, we reviewed 13 patients who had this procedure between 1981 and 1996. The mean age of the patients at operation was 8.9 years (3.7 to 16) and the mean follow-up was 4.8 years (1.3 to 10.8). Bladder function before and after operation was assessed clinically and quantitatively by urodynamics. The mean preoperative kyphosis was 117 degrees (52 to 175) and decreased to 49 degrees (1 to 89) immediately after surgery. At the latest follow-up, a mean correction of 52% had been achieved. Only one patient showed deterioration in bladder function after operation. Eight out of the nine patients who had urodynamic assessment had improvement in bladder capacity and compliance, and five showed an increase in urethral pressure. One patient developed a spastic bladder and required subsequent surgical intervention. Cordotomy, at or below the level of the kyphosis, allows excellent correction of the structural deformity. (+info)
Percutaneous cervical cordotomy for the control of pain in patients with pleural mesothelioma.
BACKGROUND: Severe chest pain is common in mesothelioma. Percutaneous cervical cordotomy, which interrupts the spinothalamic tract at the C1/C2 level causing contralateral loss of pain sensation, is particularly appropriate in mesothelioma as the tumour is unilateral and systemic analgesia may be ineffective and is limited by harmful side effects. METHOD: A retrospective review was performed to determine the effectiveness and complication rate of this procedure. RESULTS: Fifty two patients were using opioids prior to cordotomy. The median daily dose of morphine before and after cordotomy was 100 mg (range 0-1000 mg) and 20 mg (range 0-520 mg), respectively (p < 0.001). Forty three patients (83%) had a reduction in pain such that their dose of opioid could be at least halved. Twenty patients (38%) were able to stop completely. Recurrence of pain requiring an increase in opioid medication was recorded in 18 patients at a median time of nine weeks (range 0.7-26 weeks). Four patients developed mild weakness, two had troublesome dysaesthesia. The median time from cordotomy to death was 13 weeks (range 0.3-52 weeks). Six early deaths within two weeks of cordotomy occurred early in the series and reflect postoperative chest infection and poor selection as the patients were in the terminal stages of mesothelioma. CONCLUSIONS: Percutaneous cervical cordotomy is successful in treating pain from mesothelioma. There was a low complication rate in this series. Referral to a unit experienced in cordotomy is recommended as soon as pain from chest wall invasion is suspected. (+info)
Persistence of hybrid fibers in rat soleus after spinal cord transection.
The effects of a chronic (up to 360 days) reduction in neuromuscular activity (defined as electrical activation and loading) on myosin heavy chain (MHC) isoform expression in the rat soleus muscle were studied. A complete mid-thoracic (T7-T8) spinal cord transection (ST) was used to induce a reduction in soleus muscle neuromuscular activity. Electrophoretic analyses revealed that MHC-I was progressively decreased after ST, accounting for approx. 90% of the total soleus MHC in controls and only approx. 12% 1 year after ST. The reductions in the proportion of MHC-I were countered by increases in MHC-IIa and MHC-IIx with the increase in MHC-IIx preceding the increase in MHC-IIa. Curiously, MHC-IIb was expressed only at very low levels. Thus, a complete transformation from predominantly MHC-I to MHC-IIb did not occur. Many fibers (up to approx. 80%) contained multiple MHCs (hybrid fibers) after ST. The proportion of hybrid fibers was maintained at a high level (approx. 50%) 1 year after ST. These data suggest that: 1) a prolonged reduction in neuromuscular activity was not sufficient to induce high level MHC-IIb expression by the soleus muscle; and 2) hybrid fibers were not simply transitional fibers. Thus, it appears that under appropriate conditions hybrid fibers may represent a "stable" fiber phenotype. (+info)
The analgesic action of nitrous oxide is dependent on the release of norepinephrine in the dorsal horn of the spinal cord.
BACKGROUND: The authors and others have demonstrated that supraspinal opiate receptors and spinal alpha2 adrenoceptors are involved in the analgesic mechanism for nitrous oxide (N2O). The authors hypothesize that activation of opiate receptors in the periaqueductal gray results in the activation of a descending noradrenergic pathway that releases norepinephrine onto alpha2 adrenoceptors in the dorsal horn of the spinal cord. METHODS: The spinal cord was transected at the level of T3-T4 in rats and the analgesic response to 70% N2O in oxygen was determined by the tail flick latency test. In a separate experiment in rats a dialysis fiber was positioned transversely in the dorsal horn of the spinal cord at the T12 level. The following day, the dialysis fiber was infused with artificial cerebrospinal fluid at a rate of 1.3 microl/min, and the effluent was sampled at 30-min intervals. After a 60-min equilibration period, the animals were exposed to 70% N2O in oxygen. The dialysis experiment was repeated in animals that were pretreated with naltrexone (10 mg/kg, intraperitoneally) before N2O. In a third series, spinal norepinephrine was depleted with n-(2-chloroethyl)-n-ethyl-2-bromobenzylamine (DSP-4), and the analgesic response to 70% N2O in oxygen was determined. RESULTS: The analgesic effect of N2O was prevented by spinal cord transection. After exposure to N2O, there was a fourfold increase in norepinephrine released in the first 30-min period, and norepinephrine was still significantly elevated after 1 h of exposure. The increased norepinephrine release was prevented by previous administration of naltrexone. Depletion of norepinephrine in the spinal cord blocked the analgesic response to N2O. CONCLUSIONS: A descending noradrenergic pathway in the spinal cord links N2O-induced activation of opiate receptors in the periaqueductal gray, with activation of alpha2 adrenoceptors in the spinal cord. N2O-induced release of norepinephrine in the dorsal horn of the spinal cord is blocked by naltrexone, as is the analgesic response. Spinal norepinephrine is necessary for the analgesic response to the N2O. (+info)
Central regulation of sympathetic neuron development.
The sixth lumbar (L-6) ganglion has been used to study the central regulation of peripheral sympathetic neuron development. During post-natal ontogeny, tyrosine hydroxylase [tyrosine 3-monooxygenase, L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating), EC 188.8.131.52] activity increased 60-fold, while total protein rose 10-fold in the ganglion. Transection of the spinal cord at the fifth thoracic (T-5) segment in neonatal rats prevented the normal developmental increase in tyrosine hydroxylase activity of the L-6 ganglion. However, spinal transection did not alter the ontogeny of tyrosine hydroxylase in the superior cervical ganglion, which derives its innervation from spinal segments rostral to the surgical lesion. Thus, spinal transection interfered with the maturation of sympathetic neurons distal to, but not proximal to, the lesion. The effect of transection on the L-6 ganglion persisted for at least one month, the longest time tested. Our observations suggest that trans-synaptic regulation of adrenergic maturation in the periphery is governed by suprasegmental mechanisms in the central nervous system. (+info)
The effect of 2-deoxy-D-glucose and D-glucose on the efferent discharge rate of sympathetic nerves.
Efferent discharges were recorded from nerve filaments dissected from the adrenal and renal nerves in the rabbit. 2. An increase in discharge rate was observed in the adrenal nerve filaments following I.V. administration of 2-deoxy-D-glucose (2-DG). No change in discharge rate after 2-DG infusion was observed in the renal nerve filaments. 3. A decrease in discharge rate of the adrenal nerve filaments was observed after I.V. injection of glucose, but there was no change in the activity of renal nerve filaments. 4. Transection of the spinal cord abolished the adrenal nerve response to the systemic administration of 2-DG and glucose. 5. It is suggested that there might be a pathway from the hypothalmic area to the adrenal nerve cells of the spinal cord, but not to the renal nerve cells, through which activity of the adrenal nerve might be changed in response to 2-DG and glucose infusion. (+info)
High cervical commissural myelotomy in the treatment of pain.
High cervical myelotomy was carried out on 10 patients. Commissurotomy was performed at the C1-3 level by a combined procedure of deep electrocogulation and sharp splitting of the posterior columns. The immediate results were excellent in all patients, but relapse of pain took place shortly in six of them; there was apparently no relation with the location of pain. No long-term favourable results were observed in this series. Only three patients exhibited a well-defined band of mild hypalgesia from C2 to T 10 dermatome, but it lasted for only three to four weeks. Transient lower or four limb ataxia was observed in seven patients. Different pain conducting systems seem to be affected by commissural myelotomy, but not to a sufficient extent to give permanent or long-lasting relief of pain. The indications for high cervical myelotomy are very limited: this procedure should be considered only in patients with unilateral or bilateral arm and/or upper chest pain, respiratory impairment, and short life expectancy. (+info)
The crossing of the spinothalamic tract.
The question whether the spinothalamic and spinoreticular fibres cross the cord transversely or diagonally was investigated in cases of anterolateral cordotomy and in a case of thrombosis of the anterior spinal artery. The pattern of sensory loss following transection of the anterolateral quadrant of the cord consists of a narrow area of decreased nociception and thermanalgesia at the level of the incision; it extends for 1-2 segments cranial and cordal to the incision. This area is immediately cranial to the area of total loss of these modalities. This pattern of sensory loss is explained as follows. The cordotomy incision transects two groups of fibres: those that are already within the anterior and anterolateral funiculi and those that are crossing the cord. The area of total thermanaesthesia and analgesia is due to transection of fibres that are already within this region. The area of partial sensory loss is due to transection of the fibres that are crossing the cord at that level. Owing to the craniocaudal extent of the branches of the dorsal roots, there is an overlap of their collaterals that results in every spinothalamic neurone receiving an input from several dorsal roots. The narrow cordotomy incision thus divides the few fibres crossing at that level, causing diminished noxious and thermal sensibility over a few segments above and below the incision. These facts can be accounted for only on the assumption that these spinothalamic fibres are crossing the cord transversely. This evidence of transverse crossing was found in the cervical, thoracic and lumbar segments. There were three of 63 cordotomies for which this explanation of the partial sensory loss could not be maintained. Although no explanation has been suggested, this is unlikely to be due to the fibres crossing the cord diagonally. (+info)