Surgical Anatomy Of Dorsal Root Entry Zone of Cervical Spinal Nerves – Cadaveric Study.

Background: The main purpose of this study is to determine the detailed morphometric data of Dorsal Root Entry Zone (DREZ) of cervical spinal nerves. This knowledge is necessary for diagnosis, treatment and surgical management of pain due to many conditions like brachial plexus avulsion injury, post-herpetic neuralgia, phantom pain and cancer pain involved in cervical myelo-radiculopathy. There are fewer studies reported in this field of DREZ. Materials and Methods: Twenty five adult formalin fixed cadavers are taken for this study. Conventional Spinal cord dissection is followed as per Cunningham’s Dissection Mannual. Findings: The parameters included are Number of dorsal rootlets, Longitudinal Length of DREZ, Distance between two successive DREZ, Length of dorsal rootlets, Distance between right and left DREZ, Distance between DREZ and Ligamentum denticulatum, Cranial angles of Superior & inferior rootlets. Results: Results were noted for all the parameters and are compared with the previous studies. The significant observations are obtained. Conclusion: Surgical anatomy of Dorsal Root Entry Zone (DREZ) of cervical spinal nerves will be useful for the neurosurgeons doing Drezotomy procedure, in which the nociceptive fibres alone are specifically severed with preservation of other sensations.

Long Term Results of Microsurgical Dorsal Root Entry Zonotomy for Upper Extremity Spasticity

OBJECTIVE: The purpose of the present study is to assess the long-term results of microsurgical dorsal root entry zonotomy (MDT) for the treatment of medically intractable upper-extremity spasticity. METHODS: The records of nine adult patients who underwent MDT by one operating neurosurgeon from March 1999 to June 2004 were retrospectively reviewed by another investigator who had no role in the management of these patients. In all patients, MDT was performed on all roots of the upper limb (from C5 to T1) for spasticity of the upper extremity. The degree of spasticity was measured by the Modified Ashworth Scale (grade 0-4). Severity of the pain level was determined using the Numeric Rating Scale (NRS, score 0-10). Also, patient satisfaction of the post-operative outcome was assessed. RESULTS: Comparing the preoperative and postoperative spasticity using the Modified Ashworth Scale, we observed improvement in all patients, particularly in five of the nine patients (55.6%) who improved by three grades over an average of 66.4 months (range, 40-96). Regarding patient satisfaction, seven patients (77.8%) had affirmative results. None of the patients experienced severe, life-threatening, postoperative complications. We observed a decrease in the intensity of painful spasms to less than three scores as measured by NRS in all four patients with associated pain. CONCLUSION: This study shows that MDT provides significant, long-term reduction of harmful spasticity and associated pain in the upper limbs.

Nucleus Caudalis DREZ Lesioning for Intractable Pain due to Invasive Sarcoma in Skull Base: Case Report

We present a case of nucleus caudalis DREZ operation for medically refractory facial pain due to invasive sarcoma in skull base. The patient showed excellent pain relief immediately after the operation. Until 5 month later, the pain was less than before surgery. At the point of view of pain characteristics and distribution, it was considered the trigemino-vago-glossopharyngeal neuralgia. It is suggested that the nucleus caudalis DREZ operation is effective in treating medically refractory facial pain due to invasive sarcoma in skull base.

The Results of DREZ Operation on Deafferentation Pain

OBJECTIVE: The authors present dorsal root entry zone(DREZ) operations on deafferentation pain patients suffered from brachial plexus avulsion(BPA), phantom pain(PP) and postherpetic pain(PHP). METHODS: Eight patients(Six BPA, one PP and one PHP) underwent DREZ operations on the cervical, thoracic and thoracolumbar spinal cords. The patients were 7 men and 1 woman who were in between thirties and sixties. The lesions were made by inserting 2mm bare tip of standard type DREZ electrode connected to Radionics radiofrequency generator into the DREZ 45 degree off the sagittal plane. The tissue was heated to 75degrees C for 15 seconds. RESULTS: All BPA patients had immediate and long-lasting pain relief regardless of the duration and character of the pain but patients with PP and PHP complained rather aggravation of pain after the operation. CONCLUSION: DREZ operation is effective for BPA pain, however, it needs to have attention in performing this surgery for PP or PHP.

A lesão do trato de Lissauer e do corno posterior da medula espinal e a estimulação do sistema nervoso central para o tratamento da neuralgia pós-herpética / DREZ lesions and electrical stimulation of the central nervous system fortreatment of post-herpetic pain

Dor é uma complicação freqüente em doentes que apresentam erupção pelo vírus do herpes zóster. Os autores descrevem os resultados do tratamento operatório de 22 doentes com neuralgia pós-herpética. Sete doentes foram tratados pela técnica de lesão do trato de Lissauer(TL) e do corno posterior da medula espinal (CPME), sete pela técnica de estimulação elétrica da medula espinal, dois doentes por ambos os procedimentos e seis pela técnica de nucleotratotomia trigeminal estereotáxica. Foi observada significativa melhora imediata em 66,7%dos doentes com a técnica de estimulação medular, sendo mantida em 44,4% dos doentes a longo prazo. Ocorreu significativa melhora imediata em 50% dos doentes tratados pela nucleotratotomia trigeminal. A longo prazo, 33,3% dos doentes foram beneficiados. Foi observada melhora significativa imediata em 88,9% dos doentes tratados pela técnica da lesão do TL e do CPME. A longo prazo, a melhora foi observada em 66,6% dos casos. Síndrome cordonal posterior temporária ocorreu em dois doentes tratados pela nucleotratotomia trigeminal. Ela foi permanente em dois doentes tratados por essa técnica e em quatro pela lesão do TL e do CPME. Dos doentes tratados pela lesão do TL e do CPME ocorreu discreta hemiparesia permanente em quatro e um faleceu de embolia pulmonar durante o oitavo dia de pós-operatório. Concluiu-se que a lesão do trato de TL e do CPME e a estimulação elétrica da medula espinal proporcionaramresultados similares a longo prazo (p > 0,05). A técnica de estimulação, entretanto, é mais segura.

Post-herpetic pain is a very common and incapacitating disease. The authors analyse the effectiveness of the technique of dorsal root entry zone (DREZ) lesions, stereotaxic trigeminal nucleotractotomy (TNT) and dorsal column stimulation (DCS) for treatment of post-herpetic neuralgia. Twenty two patients were treated. Seven underwent DREZ; 7, DCS; 2 underwent both DREZ and DCS and 6, TNT. Immediate improvement (for 3 to 60 months ? median 12 months) of the symptoms occurred in 88.9% of the patients treated by DREZ. After a long term follow up period satisfactory results were observed in 66.7% of these patients. TNT resulted in significant immediate improvent of 50.0% of the patients and a long term (3 to 120 months ? median 8.5 (months) improvement of 33.3% of the cases. The DCS resulted in immediate improvement of pain in 66.4% of the patients. During a long term follow up period (6 to 18 months ? median 12 (months), 44.4% of the patients were better.The complication rate was higher among DREZ and TNT patients. It was concluded that the results of DREZ, TNT and DCS are similar (p > 0.05). However, DCS is safer, specially in cases of post-herpetic neuralgia affecting intercostal roots.

The Efficacy of Doral Root Entry Zone(DREZ) Lesions Making for Intractable Pain and DREZ-otomy for Inractable Spasticity

The dorsal root entry zone(DREZ) lesions making by focal destruction of the substantia gelatinosa controls intractable pain, and the DREZ-otomy by the selective destroying mainly the laterally located nociceptive and centrally located myotactic afferent fibers within the posterior root relieves the spasticity of the limbs. The authors analysed the results of 12 patients, treated by the DREZ lesions making for intractable pain, and 6 patients, treated by the DREZ-otomy for intractable spasticity of lower extremities, who were admitted to department of neurosurgery of Soonchunhyung University from 1983 to 1993. The obtained results were as follows. 1) Among the 12 patients suffered from intractable pain, three were brachial plexus avulsion, three were spinal cord injury, two were causalgia, and the others were paraneoplastic syndrome, metastatic carcinoma, postoperative spinal cord tumor, and atypical facial pain respectively. There were six patients intractable spasticity of that major cause was diffuse axonal injury(67%), and of that major posture was decorticate rigidity(83%). 2) The rate of immediate relief of intractable pain and spasticity was 82% in each after DREZ lesions making or DREZ-otomy. 3) The result of pain relief by the DREZ lesions making was excellent(100%) in brachial plexus avulsion, and poor(almost no relief) in paraplegic pain of spinal cord injury. 4) After DREZ-otomy on bilateral conus medullaris sparing S(2-4) segment, the degree of spasticity of lower extremitries reduced gradually to mean Ashworth scale 2.1 from mean 5. 5) Five of six patients of the bedridden state due to harmful spasticity was able to do comfortably wheel chair ambulation immediately after operation.

Pain Relief from Dorsal Root Entry Zone(DREZ) Lesions Made with CO2 Laser in Brachial Plexus Injury Patients

Treatment of pain related to various types of deafferentation remains a neurosurgical challenge. Medical therapy and conventional surgical techniques for pain relief have not been effective due to this problem. Six patients with intractable pain following a brachial plexus injury were treated with dorsal root entry zone(DREZ) lesions. These lesions were made with CO2 laser. All patients were followed from 5 months to 5 years after surgery. Two-third of the patients were relieved of more than 50% of their preoperative pain. Post-operative neurosurgical complications were ipsilateral leg weakness and loss of proprioception in 2 cases. The laser technique is exact, makes uniform lesion, shortens the duration of the procedure, lessens cord manipulation and makes shalow penetration into the surrounding spinal cord. Dorsal root entry zone(DREZ) lesions made with CO2 laser appeared to be a satisfactory treatment for brachial plexus injury patients who have failed to respond to more conservative modes of therapy.