Endoscopic Decompression of the Median Nerve for Idiopathic Carpal Tunnel Syndrome

Carpal tunnel syndrome is one of the commonest entrapment neuropathies. Hand pain and numbness are mostly the presenting symptoms. Endoscopic carpal tunnel release (ECTR) has been demonstrated to reduce recovery time and allow faster return to the work. The purpose of this prospective descriptive study was to evaluate the efficacy and advantages of (ECTR) through single proximal incision. In this study, the procedure was done for 36 hands in 36 patients. The results showed that females:male = 9:1, mean age was 42 years. Right hand dominance was 90% and affected in 67%. Preoperatively, the condition was moderate in 61% and severe in 39%. The average operating time was 10 minutes and the mean follow up period was 6 months with no major postoperative complications. In 8%, transient neurapraxia was found and resolved in 1 week and tenderness was found in 70% and resolved in 4 weeks. We concluded that endoscopic carpal tunnel release is an effective minimal incisional safe procedure with a high success rate, rapid return to work.


Introduction
Idiopathic carpal tunnel syndrome is the commonest one of the many entrapment neuropathies encountered by neurosurgeons in Egypt and all over the world. It was reported that idiopathic carpal tunnel syndrome accounts for more than 200,000 surgical procedures per year in the United States [1]. Also, it was reported that idiopathic carpal tunnel syndrome affects up to 1% of the general population and that surgical treatment continues to be the most effective treatment for this condition [2].
Idiopathiccarpal tunnel syndrome was first described as a clinical condition by Paget in 1854 and first surgery for tunnel release was performed in 1924 by Herbert Galloway [3]. The most common complications noticed after open procedure were hypertrophic or painful scars and pillar pain (pain in the thenar or hypothenar eminences). Since that, numerous advances have been made to refine this procedure [3]. In 1989, anoriginal endoscopic technique to release the transverse carpal ligament from within the carpal canal attempting to diminish the complications associated with open carpal tunnel release (OCTR) was presented. The early technique of endoscopic carpal tunnel release (ECTR) had a high incidence of complications due to little experience [4]. Later on, a single incision technique that allowed for visualization of the transverse carpal ligament throughout the procedure was developed. With better visualization and increasing surgical experience, the complications associated with ECTR diminished with more rapid return to work and daily activities and less scar tenderness [5] [6]. Different techniques described for carpal tunnel release includes: 1) Open carpal tunnel release. 2) Endoscopic carpal tunnel release via proximal 1 portal It was described that endoscopic carpal tunnel release with use of palmar portal approach through superficial plane to enable a view from above the transverse carpal ligament aiming to prevent compression of the median nerve inside the already narrow tunnel [7].

Patients and Methods
The present study is a prospective descriptive study performed over 2 years, be- Electrophysiological studies showed distal motor latency values greater than 4.5 milliseconds or there was a difference in values between the affected and the healthy hands of one millisecond or more. The sensory latency was more than 3.5 milliseconds and/or 0.5 milli-second more than that on the opposite side.

Ethical Considerations
Written informed consents were obtained from all participant patients after full explanation of the surgical technique and that their demographic and clinical data will be included in the study while patient identities will not be included.
This study was approved by the ethics committee of our department.
Surgical technique used [10]: proximal to distal gradually step by step to avoid the motor branch of the median nerve. Satisfactory release of the ligament was confirmed when subcutaneous fat droops down then the sheath was removed after replacement of the trocar. After adequate hemostasis had been obtained, small tube drain was inserted and the incision was sutured with 3 -0 vicryl subcuticularly then a sterile dressing was applied for 24 hours (Figure 1).
Complications as injury to the median nerve or its motor or superficial palmar branches, arteries or tendons were in mind. Follow up after one week then after 1, 3 and 6 months. Patients were allowed to use the hand in the following day and return to their activities as tolerated and the time was monitored. They were advised to avoid heavy work and excessive activity associated with compression of the hand. Demographic, preoperative and postoperative data were collected.
Analysis of data for this descriptive study was expressed as frequency-percentage and mean ± SD.
The patients were examined during the follow up period as regard grip and pinch function, palmar tenderness, and painful scar formation using the simple questions used by Aydin et al., (2006)

Results
This is a prospective descriptive study performed over 2 years, between Septem-  . The right to left affection ratio was 2:1. The syndrome was bilateral in 21 patients (60%) with severe symptoms in one side and mild symptoms in the contralateral side. Of them the 12 patients with left hand affection where mild symptoms were present in the right hand and 9 patients with right hand affection and mild symptoms in left hand. In 15 patients the condition was unilateral on right side with no symptoms on left side. Preoperative symptoms included pain, numbness and weakness. Pain was found in all cases (100%) with exaggerating on effort and after periods of rest especially in the early morning and in 12 patients (33%) pain used to awaken them from sleep with radiation to the forearm or arm in 18 cases (50%). Numbness and paresthesias along distribution of median nerve in the palm was found in 21 cases (60%). Weakness of hand grip was found in 6 cases (17%). An obvious wasting of the thenar muscle was noticed in 9 out of 36 cases (25%) while 27 cases (75%) had no obvious wasting. Tenderness along the tunnel found in 7 cases (20%). Tinel's sign was positive in 10 patients (28%) and Phalen's test was positive in 12 patients (33%). Nerve conduction study of the median nerve showed moderate motor latency in 22 cases (61%) and severe in 14 cases (39%) while sensory latency was moderate in 27 cases (75%) and severe in 9 cases (25%). Conservative treatment was given to all patients for at least 3 months with no response where endoscopic release was performed for all patients after informed consent. The average operating time was 10 minutes (range 8 -15 minutes).
There were no intraoperative complications as bleeding or injury to nerves (median nerve, motor branch of median nerve or palmar cutaneous branch of median nerve), tendons, or arteries in all patients. In 3 patients (8%), transient neurapraxia in the long/ring web space occurred and resolved in 1 week with the aid of anti-inflammatory and neurotonic drugs.
The mean follow up period was 6 months. There were no cases of postopera- The outcome after 6 months was: excellent in 25 cases (70%), good in 10 cases (27%), moderate in 1 case (3%) and no cases of poor outcome.

Discussion
Because of less surgical trauma, less postoperative pain, less scar formation, better cosmetic result and short recovery time, endoscopic release of idiopathic carpal tunnel syndrome was highly demanded especially with development of good endoscopic systems and rising experience with endoscopic carpal tunnel surgery. It was reported that open carpal tunnel release is associated with considerable morbidity, including prolonged tenderness of the scar and weakness of grip for as long as six months after the operation [3]. Reports of the results of a double-blind multicenter prospective randomized clinical study of the one portal carpal tunnel release [5]. These results indicate that there is less morbidity with a closed endoscopic carpal tunnel release than with an open operation. The possibility of improvement of these outcomes has generated considerable interest in the endoscopic method [5]. Many studies reported that open carpal tunnel release procedure provides lasting alleviation of symptoms in more than 80% of patients and the endoscopic method provides relief of numbness and paresthesias in higher percentage [2] [11].
A study with results of endoscopic carpal-tunnel release noted that 59 % of patients returned to normal activities and to work after 2 weeks and 86 %, after 4 weeks [4].

Limitations
This study has many limitations. First, the cost of endoscopic technique is double that of open one. Second, the number of patients is small, so, the real outcome of this technique in particular needs further studies with greater number of patients and following different techniques in comparison form.

Conclusion
Endoscopic carpal tunnel release is an effective safe minimal invasive procedure with high success rate, rapid return to work and minimal early and late complications.