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|NI FEATURE: CENTS (CONCEPTS, ERGONOMICS, NUANCES, THERBLIGS, SHORTCOMINGS) - COMMENTARY
|Year : 2019 | Volume
| Issue : 5 | Page : 1320-1322
Microscissor DREZotomy - A New Way for ‘Atraumatic Lesioning’ of DREZ
Deepak Agrawal, Kanwaljeet Garg
Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
|Date of Web Publication||19-Nov-2019|
Department of Neurosurgery, All India Institute of Medical Sciences, 720, CNC, AIIMS, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
Background and Aims: Dorsal root entry zone (DREZ) lesioning is a widely-used procedure for neuropathic pain which is refractory to other modes of treatment. However, all current techniques depend on thermal or radiofrequency (RF) lesioning of the DREZ. The authors describe a new technique in which mechanical lesioning of DREZ using microscissors.
Methods: The authors describe their technique of only using straight microscissors for the whole procedure of DREZotomy. No cautery is used except for hemostasis.
Results: Our technique is a continuing evolution of the original DREZotomy described by Nashold and Sindou, and appears more atraumatic and simpler.
Conclusion: Microscissor DREZotomy appears to be the most atraumatic way of carrying out DREZ lesioning and overcomes the disadvantages of other methods like thermal and RF lesioning.
Keywords: Dorsal root entry zone, microscissors, radiofrequency
Key Message: There are various ways by which lesion can be made in DREotomy like RF lesioning, thermal lesioning. We describe our technique of using microscissors for DREZotomy. We find our technique to be least invasive amongst all the available techniques.
|How to cite this article:|
Agrawal D, Garg K. Microscissor DREZotomy - A New Way for ‘Atraumatic Lesioning’ of DREZ. Neurol India 2019;67:1320-2
Dorsal root entry zone (DREZ) lesioning is a widely-used procedure for neuropathic pain which is refractory to other modes of treatment. This procedure was developed by Dr. Blaine Nashold. The commonest indication of DREZ lesioning in our set up is neuropathic pain after traumatic brachial plexus injury or lumbosacral plexus injury. Other rare indications include deafferentation pain syndromes secondary to surgical treatments or malignancy. Postherpetic neuralgia and post-amputation phantom limb pain can also be treated successfully with DREZ lesioning. The cause of this neuropathic and deafferentation pain syndromes has been hypothesized to be hypoactive inhibitory interneurons along Rexed lamina I to V, which results in disinhibition of second-order pain signal transmission.
The various ways of creating lesion are CO2 laser, using the bipolar cautery, radiofrequency ablation and thermocoagulation.,, These techniques are well established techniques with favourable results described in the literature. Sindou et al. proposes the use of bipolar forceps at low setting for this purpose. Young et al. compared 3 different techniques of lesioning - radiofrequency (RF) method using a 0.5 × 2-mm stainless steel electrode with control of electric current and duration (Group 1:21 cases); the CO2 laser (Group 2:20 cases); and an RF method, using a 0.25 × 2-mm stainless steel electrode with control of electrode temperature and duration (Group 3:37 cases). Pain relief was seen in 67%, 45% and 68%, respectively. Neurological complications including mainly ipsilateral leg weakness or loss of proprioception occurred in 52.3% of the patients in Group 1, 15% of the Group 2 patients, and 8.1% of the Group 3 patients. These results support the view that DREZ lesions may be made most effectively and safely with the RF lesioning technique associated with control of electrode temperature and duration. Various techniques of lesioning has been summarized in [Table 1].
All the above techniques are associated with some amount of thermal damage to the dorsal columns and lateral corticospinal tracts as the plane between these tracts have to be developed to reach the root entry zone. We describe our technique wherein only microscissors are used throughout the procedure.
| » Technique|| |
We have further refined the technique by only using microscissors for this purpose. No cautery is used except for hemostasis. In our technique, the spinal cord is exposed in a standard fashion after hemilaminectomy. DREZ is usually located anterior to the origin of nerve roots. If the nerve roots are absent because of the injury, one can look for the nerve roots located superior and inferior to site of interest and it is easy to identify DREZ using microscope at high magnification. Small straight microscissors [Figure 1] is used thereafter. We mark the tips of the microscissors blade at 2-mm with a sterile permanent marker [Figure 2]. This will guide us about the depth of the lesion to be created. The pia between the dorsal tracts and spinothalamic tracts is cut using the microscissors and plane developed between the two tracts in an atraumatic fashion. Both tracts can be discerned easily under the microscope and vessels traversing them in a vertical fashion. The plane is developed further till a depth of 2-mm using the marking on the microscissors. We usually continue the procedure one level superior and inferior of the involved spinal cord segments.
| » Discussion|| |
DREZ lesioning is a very simple and effective procedure. It should be done by all the neurosurgeons, especially in developing countries where neurosurgery is not subspecialized yet. Therefore, doing this procedure by commonly available instruments will make this simple procedure more commonly used.
When using bipolar forceps, very fine 0.1 mm tip is required for this purpose. It can be difficult and costly to get such a special instrument in developing countries and especially where DREZ lesioning is not done very commonly. Moreover, there is spread of current/heat while using bipolar forceps, while with microscissors the lesion is created without affecting the surrounding tissues.
Our technique is a continuing evolution of the original DREZotomy described by Nashold and Sindou which aimed at destroying cells in the substantia gelatinosa in the laminae of Rexed I and II. Takai et al. proposed a modification of the existing procedure of DREZ lesioning by including the deeper layers of the posterior horn of spinal gray matter, including the lamina of Rexed V. This was a hypothesis that deeper layers of the posterior horn in spinal gray matter are also associated with pain conduction., The authors divided the spinal cord into the posterior and lateral funiculi using a microsurgical probe per the fiber bundles of the spinal tracts. The posterior horn was lesioned using a microsurgical tumor forceps with a blunt dissection technique at a depth of 4-5 mm from the surface of the DREZ. They demonstrated that total and persistent global pain relief was achieved with the modified DREZ lesioning procedure in 90% of patients without major neurological deficits. We think that this type of modified DREZ lesioning can be very easily performed in a more atraumatic manner using microscissors.
| » Conclusions|| |
We believe microscissor DREZotomy is the most atraumatic way of carrying out DREZ lesioning and overcomes the disadvantages of other methods like thermal and RF lesioning.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| » References|| |
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[Figure 1], [Figure 2]