T e c h n o l o g y S e r v i n g T e c h n i q u e

Retrograde Knife

S U R G I C A L T E C H N I Q U E

Synchronized Endoscopic Guide System for Endoscopic Carpal Tunnel Release

Orthopaedics, Inc.

Authored by:Charles F Leinberry, MD Rothman Institute, Hand SurgeonFellow of the American Academy of Orthopaedic SurgeonsDiplomat, American Board of Orthopaedic SurgeryAmerican Society for Surgery of the Hand American Association for Hand Surgery

INTRODUCTION

Open release of the carpal ligament has been shownto have a somewhat longer recovery time and canalso result in a frayed ligament with some loss ofstrength. Because endoscopic carpal tunnel releasehas been shown to have advantages includingsmaller incisions with less pain and faster recovery,it has become a popular technique for releasing thecarpal tunnel over the last 15 to 20 years.

SegWAY ™ is an endoscopic ligament and fasciarelease system that utilizes a guide that separates the scalpel from the endoscope, allowing the two to move independently of each other. SegWAYprovides the extremity surgeon with the tactile feel of an endoscopic scalpel, while giving the patient the bene�ts of a minimally invasive surgicalsolution. SegWAY’s increased �exibility results in greater control and superior visualization.

The patient should receive Monitored Anesthesia Care(MAC) with additional local in�ltrative anesthesia at theoperative site. The surgeon will usually be seated in the armpitof the patient and a tourniquet applied to the upper forearm.The SegWAY carpal tunnel set can be used with a standardoperating room scope, 4mm 30 degrees, which will �t easilyin either the right or left guides (which are supplied with theSegWAY instrument system). Anti-fog agent should beapplied to the scope lens to prevent fogging of the lens duringthe procedure. Once the scope is prepared, the sterileretrograde knife can be opened, along with the instrument setcontaining the left and right cannula. The canal/tunnel dilatoris also available in the kit.

PATIENT SELECTION

Endoscopic carpal tunnel release can be performedfor carpal tunnel syndrome on most patients whohave failed to respond to non-surgical treatment,including non-steroidal anti-in�ammatories, splintprotocol, and cortisone shots.

Excluded candidates are those who have had aprevious carpal tunnel release procedure or thosewho are sti� and unable to extend the wrist area.Also patients with a known diagnosis ofrheumatoid arthritis, or those who are suspected of having signi�cant tenosynovitis would not beappropriate candidates. Patients should also beexcluded if there is a suspected unusual cause for their carpal tunnel syndrome, such as a ganglion cyst.

1. PATIENT PREPARATION & SETUP

A sterile skin marker is used to map out the landmarks for theanatomy and establish the entry portal for the carpal tunnelprocedure. The hook of the hamate can be palpated in linewith the ring �nger. The distal and proximal wrist �exioncreases are also to be noted.

2. ANATOMY & LANDMARKS

A 1cm long incision is marked just ulnar to the palmarislongus tendon (if present) between the proximal and distal�exion creases. The ulnar edge of the incision mark shouldextend approximately 2mm past a line bisected by a linedrawn along the ring �nger. After in�ltrating with a 50%mixture of Lidocaine and Marcaine and administeringappropriate IV sedation, the skin incision may be made.

3. INCISION

After the skin incision is made, dissection proceeds in the softtissue to reveal the transverse carpal ligament at its edge whereit turns into forearm fascia. If the palmaris longus tendon ispresent, it can be retracted to the radial side. A transverseincision is made in the transverse carpal ligament/forearmfascia at this level and, using a pair of Brown Addisonpickups, the ligament is elevated. While feeling the hook ofthe hamate as the dilator passes, the blunt dilator is nowintroduced to create access for the Seg -WAY guide. Thedilator should readily pass through the tunnel and exit in the mid-palm area, which is easily palpable. Carefully, move theblunt dilator both ulnarly and volarly and it should stay in asecure position as its movement will be impinged by both thehamate and the transverse carpal ligament. The ridges of theligament also can be palpated with the curved elevator.

4. PATH CREATION

After the appropriate path has been created, the right or leftSeg-WAY guide is chosen. (The Seg-WAY guides aremarked R for procedures involving a patient’s right-hand or Lfor procedures involving a patient’s left-hand.) The scope maybe held in the surgeon’s right or left hand, according to thesurgeon’s preference, and the small probe and rasp are used tocon�rm that the transverse carpal ligaments are visualized.Positioning the guide and the scope to allow for appropriatevisualization of the �bers is critical at this point. The distaledge of the ligament is con�rmed by the fat pad, whichprotrudes distal to the ligament at the level of the mid-palm.It is essential at this time, while probing and rasping theligament, to determine if there are any signi�cant electricalsensations in the patient’s �ngers—this must be noted andchecked to ensure that there is no median nerve or abnormalbranch in the visual �eld. If the nerve cannot be displaced outof the �eld, the procedure should be converted to an openprocedure.

5. INSERTION OF SCOPE & SEG-WAY GUIDE

6. RELEASE & CLOSURE

POSTOPERATIVE CARE

The postoperative care is as usual, allowing thepatient full �nger range of motion the next daywith use of the hand for activities as tolerated. No splint is required in this procedure. Allow at least four weeks before heavy work or otherstrenuous activity. Assuming no pain, the patientcan perform functional activities as tolerated.

Scope Right, Guide: Scope isfreed from the knife tomaximize visualization

Scope Left, Guide: Elevatortip facilitates insertion

8cm

A sterile cotton swap can be used in a twirling motion toclean any extra synovium prior to sectioning the ligament.After this is accomplished, the retrograde knife is used to startat the fat pad and create a cut along the ligament from distalto proximal. The blade is pulled carefully in line, keeping ittowards the center or ulnar side under direct visualization bygradually and partially withdrawing the scope—in synch withthe blade movement—until the proximal end of the ligamentis visualized. At this point a 2mm proximal edge of theligament can be left intact to void a skin laceration. Inaddition, the scope can be rotated, both to the radial andulnar side, to con�rm complete release of the ligament. Ifthere are any remaining �bers, the retrograde knife can beused to release these remaining �bers.

NOTE: The light from the scope should now be easily visibleunderneath the skin and can be used to con�rm release of theligament. By dimming the overhead lights in the operating room,the scope light can easily be seen along the entire length of theprocedure area.

Under direct visualization the remaining 2mm proximal edgeof transverse carpal ligament can be sectioned using a smallStevens tenotomy scissor. The proximal forearm fascia shouldalso be released under direct visualization for 1cm proximalprior to skin closure. The wounds are then copiously irrigatedwith sterile saline, the proximal incision closed with 4.0 nylonsutures, and a routine soft dressing is applied.

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