Indications
Contraindications
Idiopathic CTS
Recurrent CTS
Anticoagulation
Inflammatory conditions (i.e., rheumatoid arthritis, amyloidosis)
Severe CTSa
CTS secondary to fracture/trauma
Additionally, many surgeons believe that ECTR should be avoided in patients with certain preexisting conditions, including anticoagulation and inflammatory conditions such as rheumatoid arthritis or amyloidosis. Since hemostasis is a concern in the setting of anticoagulation, the conventional open approach is the preferred technique in order to avoid bleeding complications that may be better avoided by open surgical visualization. ECTR in patients with inflammatory conditions should also be approached with caution. Patients with rheumatoid arthritis or other inflammatory conditions have a higher risk of synovial lesions or other pathology which can interfere with visualization of the carpal tunnel, or occasionally even the introduction of endoscopic device at the wrist. Endoscopic technique also precludes synovectomy, which may be necessary in some of these patients. That said, ECTR can be performed reliably in inflammatory arthritis patients whose disease is quiescent [8]. ECTR should also be carefully considered in patients with a history of trauma or hand/wrist fractures, since these events can perturb the bony anatomy of the carpal tunnel. Lastly, some argue that patients with severe median nerve compression necessitating extensive neurolysis or tenosynovectomy should instead undergo conventional open CTR, as these adjunctive procedures cannot be performed via an endoscopic approach [9, 10].
Surgical Techniques
Positioning
In general, with any ECTR technique , the patient is placed supine with the arm abducted on an operating arm table. The surgeon is positioned on the medial side of the abducted arm (if right hand is the dominant hand) in order to facilitate the use of the dominant hand for maneuvering the endoscope, while the assistant is positioned on the opposite side. Some surgeons prefer to use their dominant hand for all cases (requiring them to sit on the head side of the hand table to release the nondominant hand), while others prefer to maintain their position on the axillary side of the hand table (and use their nondominant hand to release the nondominant hand of the patient).
Anesthesia
ECTR can be performed using general, regional, and local anesthesia. More commonly, regional and local anesthesia is used, with general anesthesia reserved for those unable to tolerate local or regional blocks. Several studies have examined the efficacy and the postoperative outcomes with local versus regional anesthesia. While some studies have suggested less cost and equally effective intraoperative analgesia with local-only techniques, our experience is that injection of local anesthetic into the skin over the transverse carpal ligament creates fogging of the endoscope and poor visualization, requiring an unacceptably high rate of conversion to open procedure in these circumstances [11].
In our practice, we generally use local anesthesia with IV sedation, and it is well tolerated. The distal wrist crease and proximal forearm fascia are infiltrated with a 1:1 solution of 1% lidocaine with epinephrine with 0.5% plain bupivacaine. A tourniquet is utilized, and it is inflated to 250 mmHg after local anesthesia infiltration to reduce bleeding.
Endoscopic Approaches
Currently, there are three main distinct types of ECTR techniques performed (Table 13.2). The most commonly performed technique is the single proximal portal technique, first described by Agee in 1992 [4]. This technique utilizes a proprietary device (MicroAire, Charlottesville, VA) which is composed of a 2.7-mm 30-degree-angle arthroscope, a fiber-optic light source and camera, and a handpiece with attached disposable blade cartridge into which the endoscope is inserted (Fig. 13.1A, B). The Chow dual-portal technique was introduced by James C. Y. Chow in 1989 [3]. Unlike the Agee technique, the Chow technique uses a two-port approach which creates a fixed space in which to operate. A cannula is fixed at the proximal and distal portals, and a 4-mm 30-degree endoscope with an incorporated knife is inserted at the proximal portal, which is then used to incise the TCL (Fig. 13.2a, b). Lastly, in 1995, M. Ather Mirza described a single distal portal approach which utilizes a 1.5-cm longitudinal palmar incision along the thenar crease, a standard 4-mm 30-degree endoscope, and a knife/sleeve device which is used to divide the TCL and decompress the carpal canal [5]. The single distal portal approach can also be done using the MicroAire device (Fig. 13.3a–c) [12].
Table 13.2
Three endoscopic CTR approaches
Technique | Year of development | Description |
|---|---|---|
Agee | 1992 | Single proximal portal approach |
Chow | 1989 | Two-port approach |
Mirza | 1995 | Single-distal port approach |
Fig. 13.1
The original description of the single proximal portal technique by Agee. (A) Schematic of the relative position of the endoscopic device relative to the distal edge of the TCL (a), ulnar limit of the median nerve (b), and proximal limit of the superficial palmar arch (c). (B) The device is inserted parallel to the plane of the palm and forearm
Fig. 13.2
The Chow two-portal technique . (a) Schematic of the cannula position relative to the volar wrist structures. (b) The hand positioned on the wrist extension platform with the cannula inserted
Fig. 13.3
The single distal portal technique . (a) The incision is placed at the intersection of Kaplan’s cardinal line and the fourth ray. (b) Schematic of the location of the endoscope passage relative to the superficial palmar arch and the ulnar limit of the median nerve. (c) The endoscope is inserted into the carpal tunnel
The Single Proximal Portal Technique
The senior author has extensive experience with the single proximal portal technique so a brief description of the operative technique is provided below:
- 1.
Incision, Exposure, Insertion
A 1–2-cm transverse incision is made at the proximal flexor wrist crease ulnar to the palmaris longus. Careful dissection is performed down to the antebrachial fascia using skin hooks for exposure (Fig. 13.4). The fascia is incised by creating a distal ulnarly based L-shaped flap. The distal antebrachial fascia proximal to the incision just made is divided under direct vision with scissors. Means and colleagues demonstrated that pressure on the median nerve can remain elevated even after release of the TCL if the antebrachial fascia is intact [13]. For this reason, we always include division of the distal antebrachial fascia as part of ECTR. The maneuver takes less than a minute to perform and does not add additional cost to the procedure.
“
Fig. 13.4
The distal antebrachial fascia is exposed via a transverse incision of a volar crease immediately proximal to the volar wrist crease
- 2.
Get Clinical Tree app for offline access
Retinaculum Incision
A synovial elevator is passed distally several times along the axis of the fourth ray to elevate the synovium off of the transverse carpal ligament (TCL) deep surface (Fig. 13.5a, b). The endoscopic device is then inserted into the carpal canal (Fig. 13.6). With the TCL distal edge in full view on the endoscope monitor (Fig. 13.7), the TCL is divided from the distal to proximal edge using the device blade. If there are any issues with visibility of the TCL, the surgical approach is then converted to an open procedure.
Fig. 13.5
A synovial elevator is used to free the synovium within the carpal tunnel from the deep surface of the TCL
Fig. 13.6
The endoscopic device is inserted into the carpal tunnel parallel to the plane of the TCLRelated posts:
Severity Scoring Systems for Carpal Tunnel Syndrome and Outcome Tools
Diagnosis of True Recurrent Carpal Tunnel Syndrome
Electrical Nerve Stimulation for Chronic Median Nerve Pain
Pathophysiology of Carpal Tunnel Syndrome
Clinical Presentations and Diagnosis
Imaging of the Carpal Tunnel and Median Nerve
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
