Trigeminal neuralgia: a plea for microvascular decompression as the first surgical option. Anatomy should prevail.

Arguments are given to plead why micro-vascular decompression should be the first surgical option to treat primary trigeminal neuralgias resistant to anticonvulsants.

Trigeminal neuralgia and pain related to multiple sclerosis.

Although many patients with multiple sclerosis (MS) complain of trigeminal neuralgia (TN), its cause and mechanisms are still debatable. In a multicentre controlled study, we collected 130 patients with MS: 50 patients with TN, 30 patients with trigeminal sensory disturbances other than TN (ongoing pain, dysaesthesia, or hypoesthesia), and 50 control patients. All patients underwent pain assessment, trigeminal reflex testing, and dedicated MRI scans. The MRI scans were imported and normalised into a voxel-based, 3D brainstem model that allows spatial statistical analysis. The onset ages of MS and trigeminal symptoms were significantly older in the TN group. The frequency histogram of onset age for the TN group showed that many patients fell in the age range of classic TN. Most patients in TN and non-TN groups had abnormal trigeminal reflexes. In the TN group, 3D brainstem analysis showed an area of strong probability of lesion (P<0.0001) centred on the intrapontine trigeminal primary afferents. In the non-TN group, brainstem lesions were more scattered, with the highest probability for lesions (P<0.001) in a region involving the subnucleus oralis of the spinal trigeminal complex. We conclude that the most likely cause of MS-related TN is a pontine plaque damaging the primary afferents. Nevertheless, in some patients a neurovascular contact may act as a concurring mechanism. The other sensory disturbances, including ongoing pain and dysaesthesia, may arise from damage to the second-order neurons in the spinal trigeminal complex.

Anatomoradiological landmarks for accuracy of radiofrequency thermorhizotomy in the treatment of trigeminal neuralgia.

OBJECTIVE: The correct positioning of the electrode is of prime importance for effectiveness and selectivity of percutaneous trigeminal radiofrequency thermorhizotomy (RF-TR) for the treatment of trigeminal neuralgia (TN). The aim of our study was to establish some anatomoradiological landmarks for the purpose of accurate placement of the electrode tip in RF-TR. METHODS: Of 1000 patients who underwent RF-TR, 100 were retrospective and randomly selected and divided into study groups according to postoperative hypoesthesia in the trigeminal nerve divisions. The patients' petroclival angle, petroelectrodal angle, electrode tip, and the petroelectrodal angle/petroclival angle ratio were calculated on lateral cranial x-rays. These measurements were then correlated with the topography of hypoesthesia obtained by the RF-TR to define the anatomoradiological x-ray landmarks corresponding to the divisions of the trigeminal root. The postoperative hypoesthesia groups were correlated with their respective preoperative pain topography to check the accuracy of the thermolesion. In addition, the intraoperatively evoked paresthesia responses and the side effects were evaluated. The results were analyzed using a paired-samples Student's t test, the chi test, and one-way analysis of variance, followed by Bonferroni and Tamhane post hoc tests. RESULTS: All study groups were comparable with respect to age, sex, side effects, electrode tip location, side of TN, and values of petroclival angle. The lowest values of petroelectrodal angle/orbitomeatal electrodal angle and petroelectrodal angle/ petroclival angle were detected in patients with V3 TN, whereas the greatest values were in patients who had TN in all branches of the trigeminal nerve. The greatest height of the electrode was in patients who had TN in all branches, whereas the least height was in patients with V3 TN. When the results were compared with each other, the mean differences were found to be statistically significant between V3 TN patients and the other groups with different P values. There was no statistical difference between the postoperative hypoesthesia data and the preoperative pain topography, which demonstrated evidence of the accuracy of the thermolesion in our series. CONCLUSION: Our data suggest that the determination of the presented landmarks allows customization to individual patient anatomy and may help the surgeon achieve a more selective effect with a variety of percutaneous procedures for each branch of the trigeminal root.

Other surgical interventions.

Optimal management of patients with chronic neuropathic pain requires a multidisciplinary approach that may include surgery. Yet despite the fact that lumbosacral spinal surgery, for example, is performed in thousands of patients every year, there is very little controlled clinical data to support its use or that of other surgical techniques in the treatment of chronic nonmalignant pain, especially neuropathic pain. Nevertheless, there is evidence of some success for ablative techniques such as dorsal root entry zone lesioning for phantom limb pain and girdle-zone neuropathic pain, and sympathectomy for the treatment of complex regional pain syndrome, and a variety of operations for tic douloureux. However, before considering a surgical procedure, a nonsurgical approach should have been tried and the suitability of the patient must be carefully assessed. To fully establish the role of surgery in the treatment of chronic neuropathic pain, further well-designed, prospective, controlled trials are essential.

Microsurgical anatomy of the dorsal cervical rootlets and dorsal root entry zones.

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. METHOD: Fifteen adult formalin-fixed cadaveric spines from C1 to T1 were used to observe the posterior structures. They were studied under the surgical microscope following en bloc laminectomy and foraminotomy. The morphological features of the dorsal root entry zones and dorsal rootlets were determined. The distance from the midline to the DREZ, the longitudinal length of the DREZ in the spinal canal, the length of the dorsal rootlets, the number of dorsal rootlets and the intersegmental anastomoses between the dorsal rootlets were measured. FINDINGS: The distance from the midline to the DREZ ranged from 1.1 to 4.7 mm. Longitudinal length of the dorsal rootlets ranged 4.3-17.7 mm. The shortest length of the dorsal rootlets ranged between 5-28 mm, and longest lengths of the dorsal rootlets ranged 6.8-30.3 mm. The number of dorsal rootlets ranged from 2-13. Between the C2-T1 dorsal rootlets, 142 connections out of 30 intersegments were noted. CONCLUSIONS: The distance from the midline to the DREZ decreased in the lower cervical spine. The longest longitudinal length of the DREZ was at the C5 level. The length of the dorsal rootlets was increased in the lower cervical spine. The average number of dorsal rootlets tended to increase in the lower cervical spine. Anastomoses were most often found between C6-7 and C5-6 dorsal rootlets. Knowledge of the anatomical features of dorsal cervical rootlets and dorsal root entry zones is essential for a surgeon to avoid injuring the neural structures. This knowledge is a must not only to avoid complications but also for the success, safety and effectiveness of microsurgical operations of the pathological conditions like posterior myeloradiculopathy and pain treatment such as DREZ operations.

Developmental skills of children with spastic diplegia: functional and qualitative changes after selective dorsal rhizotomy.

OBJECTIVE: This study examined changes in muscle tone, passive range of motion, stability, and mobility in developmental skills at 6 months and 1 year after selective dorsal rhizotomy (SDR). DESIGN: Prospective outcome study of a consecutive sample. SETTING: Private children's hospital. PATIENTS: Twenty-six children with spastic diplegia: 13 independent and 13 dependent ambulators (assistive devices). RESULTS: A decrease in spasticity was seen at 6 months after SDR, with no further decrease at 1 year. Increases in passive range of motion of the hip and ankle were seen at 6 months after SDR. The ability to assume and maintain developmental positions with improved alignment and stability was seen more frequently at 6 months after SDR, whereas an improvement in the ability to perform transitional movements was seen more frequently at 1 year after SDR. CONCLUSION: SDR decreases spasticity and increases lower extremity range of motion in children with spastic diplegia and appears to be associated with the ability to assume a greater variety of developmental positions with improved alignment, thus greater stability. Improvements in the ability to perform difficult transitional movements at 1 year after SDR are most likely the result of the combined effect of maturation, SDR, and intensive therapeutic intervention.

Does gait continue to improve 2 years after selective dorsal rhizotomy?

Although changes in the gait pattern of children with spastic diplegia 1 year after selective dorsal rhizotomy have been well documented, minimal information exists regarding the continued changes in the gait pattern over time. Despite improvements in gait after rhizotomy, 66-75% of patients still require orthopaedic surgery for residual deformities. The optimal timing of the orthopaedic surgery after selective dorsal rhizotomy is not well established because of the lack of information regarding changes in gait over a long term. Using three-dimensional gait analysis, the gait pattern of 23 children was evaluated preoperatively, 1 and 2 years postoperatively. There were significant improvements in hip, knee, and ankle motion at 1 year after surgery. Although improvements in the gait pattern were found between 1 and 2 years after surgery, the changes were not significant. Therefore orthopaedic intervention may be undertaken at 1 year after rhizotomy to enhance function, as changes in gait from 1 to 2 years after rhizotomy are minimal.

Sacral rhizotomies and electrical bladder stimulation in spinal cord injury. 2. Cost-effectiveness and quality of life analysis. Dutch Study Group on Sacral Anterior Root Stimulation.

OBJECTIVES: To present a cost-effectiveness analysis of sacral rhizotomies and electrical bladder stimulation compared with conventional care of neurogenic bladder dysfunction in patients with spinal cord injury. METHODS: During a 3-year inclusion period, data on costs and quality of life before the intervention were collected to describe conventional care. Data on the pre-implantation period, the implantation and a follow-up period of 2 years were collected following a strict protocol simultaneous with medical and urodynamic data and were used to calculate the costs and effects on quality of life of the implantation of the stimulator. RESULTS: Between June 1991 and June 1994, 52 patients with complete cervical or thoracic spinal cord lesions underwent sacral posterior rhizotomies and implantation of a Finetech-Brindley sacral anterior root stimulator. Although the initial costs of sacral anterior root stimulation are high, they are earned back in this series in about 8 years after the implantation. General indicators of the quality of life show no significant changes after the implantation. Factors related to psychological well-being and the patients' satisfaction with the emptying of the bladder increased significantly whereas the experienced problems of micturition and incontinence all decreased significantly. CONCLUSION: Sacral rhizotomies and electrical bladder stimulation make a cost-effective method of treatment of lower urinary tract dysfunction in patients with spinal cord injury. Considerable savings on health care costs are possible in the long run with simultaneous positive effects on aspects of health status.