- Research article
- Open Access
Endoscopic Carpal Tunnel Release using a modified application technique of local anesthesia: safety and effectiveness
© Nabhan et al. 2008
- Received: 02 December 2007
- Accepted: 25 April 2008
- Published: 25 April 2008
Local anesthesia is widely used for open carpal tunnel release. However, injection of local anesthesia as described by Altissimi and Mancini (1988) can interfere with endoscopic carpal tunnel release, by increasing the bulk of synovial layers and consequently result in worsening of the view.
The purpose of this study was to evaluate the safety, efficacy using modified technique for application of local anesthesia.
33 patients suffering from gradual increasing symptoms of carpal tunnel syndrome. The patients were also asked to evaluate the pain associated with injection as well as tourniquet during surgery using Visual Analogue Scale (VAS) (ranging from 0 = no pain to 10 = maximum pain).
One patient required additionally local anesthesia because of mild pain in the hand. The tourniquet was inflated for 13.00 (2.8 min). The pain score related to injection was 2.5 (0.8) and to tourniquet was 3.6 (0.9). Inflation of the tourniquet was well tolerated by all patients. Postoperative neurological sensory and motor deficits related to surgery and local blocks were not occurred.
Endoscopic release of the carpal tunnel syndrome in local anesthesia is effective, well tolerated and safe. This kind of application of local anesthesia did not reduce visibility.
Anesthetic options for Endoscopic Carpal Tunnel Release (ECTR) include: general anesthesia (GA), local anesthetic (LA) infiltration, intravenous regional anesthesia (IVRA), and peripheral nerve blocks (PNB). Peripheral nerve blocks can be done either proximally at the brachial plexus or more distally at the peripheral nerves. The surgery is usually done either in wrist block or within intravenous application of local anesthesia . For these ambulant procedures, it seems that local anesthesia should be especially favoured. Such a local infiltration is easy and quick to perform, especially the subcutaneous application. However, local Anesthesia has the reputation of being of limited interest because they may cause anatomical distortion at the site of incision .
Alternatives to local anesthesia, such as brachial block or IVRA, are more time consuming and the presence of an anesthetist has been recommended when these techniques are used .
This study was designed to verify the efficacy, tourniquet and injection associated pain with LA.
This study was approved by the local ethical committee of Saarland (Germany).
Age rang 18 – 70 years
Prior surgery at the wrist
Allergic to prilocain
Hand or wrist pain with paresthesias or numbness in the first three or all fingers
Deformity of the wrist bone
Symptoms presents for at least three months
No prior surgery at the wrist
Willing and able to provide informed consent ability to take part on the study
Median nerve distal motor latency > 4,5 ms
The patients were also asked to evaluate the pain associated with injection as well as tourniquet during surgery using Visual Analogue Scale (VAS) (ranging from 0 = no pain to 10 = maximum pain).
Follow-up examinations were done pre- and postoperatively. Data are presented as mean value and Standard deviation.
Altissimi and Mancini  injected local anesthetic around the median nerve under the flexor retinaculum for open carpal tunnel release. This technique potentially reduces visibility, and thus has a significant risk of nerve injury . Wood and Logan 1999  gave a subcutaneous injection of local anesthetic to allow a proximal wrist incision and an intraoperative injection of local anesthetic using a catheter with a blunt ended trochar. This method is time consuming, especially in view of tourniquet pain. Moreover deflation and a new inflation trial are not possible in cases of venous congestion.
Patil  compared two techniques of local anesthesia (the Gale technique 1990 and the Altissimi and Mancini technique 1988). Both were described for open carpal tunnel release.
This study did not support the concept that performing LA increases risk for nerve damage or causes anatomical distortion [2, 4]. The risk of transient or permanent nerve damage following blocks, which is estimated to be between 2.1 and 9%, was thought to be caused by the deep injection of anesthesia [8, 9].
Most investigators of endoscopic carpal tunnel release are skeptical about using local anesthesia [4, 10]. They believe that the tourniquet pain increases with the use of local anesthesia. Since a tourniquet has to be used, the operation must be short and the tourniquet time should not exceed 20 to 25 minutes . Moreover the application of local anesthesia as we described does not cause nerve damage. In the current study, the application of subcutaneous local anesthesia for endoscopic release of the carpal tunnel was effective. Furthermore, it is less invasive and simpler in comparison to surgery with other anesthetic options for ECTR, such as general anesthesia, intravenous regional anesthesia or peripheral nerve blocks. It's practical and can be done by the surgeon himself.
Another point of interest is that, in cases of venous congestion, deflation and re-inflation is only possible using local anesthesia.
No complaints of paresthesia were seen during injections of local anesthesia. Injection-associated problems such as increased thickness of the synovial layer or decreased endoscopic view did not occur. No instances of tendon or nerve injury or hematoma were seen.
Endoscopic release of carpal tunnel ligament in local anesthesia is safe and effective. It is less invasive and cost-saving.
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