On Resection of the Knee

In 16 patients, where the diagnosis carpal tunnel syndrome was electrophysiologi-cally confirmed, the pressure between the median nerve and the carpal ligament was measured peroperatively.

At rest the pressure was 18-64 mmHg, mean 31 mmHg. Passive volar and dorsal wrist flexion increased the pressure about three times. Isometric or isotonic maximal contractions of wrist and finger muscles, elicited by tetanic nerve stimulation increased the pressure to three to six times the resting value. These high pressures may be one of the causes of the nerve lesion in the carpal tunnel syndrome.     

小切口治疗腕管综合征14例报告

Objective　To introduce the technique of carpal tunnel release by small incision,and evaluate its outcome in the treatment of carpal tunnel syndrome.Methods　This method was applied in the operations of 14 cases of carpal tunnel syndrome.An incision 1.5 cm in length was made at the level of the proximal transverse wrist crease ulnar to the palmaris longus tendon.The proximal margin of the transverse carpal ligament was visualized and the ligament was cut subcutaneously under direct vision.The flexor digitorum tendons were retracted and the edematous synovium excised.Results　Follow - up of the patients 2 weeks postoperatively showed that the symptoms of numbess and pain disappeared in all 14 cases.Normal 2 - PD in the pulp of the thumb,index finger and long finger was ＜ 4 mm.One year after the operation,muscle atrophy in 5 patients who sustained preoperative thenar muscle atrophy was greatly improved with recovery of normal opponens function of the thumb.No pillar pain and injury of the ulnar nerve and superficial palmar arch was found.Conclusion　Carpal tunnel release under direct vision through a small incision is a new and effective surgical procedure.     

Measurement of median nerve blood flow during carpal tunnel release with laser Doppler flowmetry.

Eight consecutive median nerves in eight patients with clinical carpal tunnel syndrome were prospectively examined by non-contact laser Doppler flowmetry before and after undergoing carpal tunnel release. Before performing carpal tunnel release, the difference in the median nerve blood flow between the values at the distal and proximal portions to the transverse carpal ligament was statistically significant (p = 0.021). After carpal tunnel release, the median nerve blood flow both distal and proximal to the transverse carpal ligament increased by 1.5 and 1.3 times, respectively, compared to the flow prior to carpal tunnel release, however, only the difference at the distal portion to the transverse carpal ligament was statistically significant (p = 0.015). In this study, we directly measured the median nerve blood flow using non-contact laser Doppler flowmetry and thus demonstrated a significant difference in the median nerve blood flow between the values at the distal and proximal portions to the transverse carpal ligament before carpal tunnel release and a significant increase in the nerve blood flow only at the distal portion to the transverse carpal ligament after surgery. This technique is thus considered to be an easy and reproducible way to intraoperatively evaluate the nerve blood flow in real time during the release of entrapment neuropathies.     

Injection injuries to the median and ulnar nerves at the wrist.

Carpal tunnel syndrome is often treated nonoperatively with temporary wrist immobilization and local steroid injections. A direct injection into a peripheral nerve can result in permanent damage. Two cases of median nerve injection injury and one involving the ulnar nerve are presented; all were treated with neurolysis and debridement of the injected material. At follow-up ranging from 1 to 11 years, all patients showed significant improvement, but with some functional loss. The literature is confusing because of the variety of injection techniques used for the treatment of carpal tunnel syndrome, some of which put the median nerve at risk. We recommend that the injection be made midway between the palmaris longus tendon and the flexor carpi ulnaris tendon just proximal to the proximal edge of the transverse carpal ligament in a line with the superficialis tendon of the ring finger. The injection should be stopped and redirected if the patient experiences paresthesia of any kind.     

Release of the transverse carpal ligament alone is associated with elevated pressure beneath the distal volar forearm fascia in a cadaver model of carpal tunnel syndrome

PURPOSE: The purpose of this study is to determine whether release of the distal volar forearm fascia (DVFF) is necessary at the time of median nerve decompression for carpal tunnel syndrome. METHODS: Five fresh-frozen cadaver specimens were mounted vertically with the hand dependent and a 2.27-kg weight suspended from the fingers. A pressure sensor wire was used to measure pressures starting just distal to the transverse carpal ligament (TCL). The wire was withdrawn proximally in 5-mm increments and into the forearm until pressure was below 10 mm Hg. An incision in the forearm was extended distally until the pressure sensor was found. The distance from this point to the distal volar wrist crease was measured. The TCL was released, keeping the DVFF intact, and the experiment was repeated. Paired t-tests determined whether there were statistically significant differences between measurements before and after TCL release. RESULTS: Average peak pressure under the intact TCL was 57.8 +/- 10.1 mm Hg. Average peak pressure under the DVFF with the TCL intact was 61.2 +/- 43.6 mm Hg. Following release of the TCL, average peak pressure beneath the TCL significantly decreased to 14.0 +/- 9.0 mm Hg, whereas average peak pressure at the intact DVFF increased to 64.8 +/- 48.7 mm Hg. Average locations where DVFF pressure became less than 10 mm Hg with an intact TCL and with released TCL were 4.30 +/- 1.8 cm and 4.00 +/- 1.8 cm proximal to the distal volar wrist crease, respectively. There was no significant difference between DVFF pressures before or after TCL release. CONCLUSIONS: In a cadaver model of carpal tunnel syndrome, release of the TCL alone is associated with persistent pressures >30 mm Hg in the region of the DVFF. Release of the TCL did not significantly change the location of the pressure drop-off under the DVFF.     

内镜下两点单侧钩切法治疗腕管综合征的临床应用

目的：探讨应用内镜的两点单侧钩切法切断腕横韧带,解除正中神经压迫的手术方法和疗效。方法：临床治疗原发性11例13侧（左侧3例,右侧6例,双侧2例）43～68岁女性腕管综合征患者。全部患者均有桡侧3个半指的指端刺痛觉减退,腕部正中神经Tinel征阳性,11例大鱼际肌萎缩,同时4例存在拇指对掌功能减弱。术中局部麻醉,分别采取近侧腕横纹线处,掌长肌腱与桡侧屈腕肌腱之间1cm皮肤横切口（入口）和患者拇指最大桡侧外展位,拇指尺侧平行线与中环指间的长轴线交叉点向尺侧1cm处呈45°切口（出口）。预制隧道后入口处置入腕关节镜,由出口插入钩刀。钩刀钩住腕横韧带近段后,内镜随钩刀移动而远行,全程镜视下由近及远切断腕横韧带。结果：患者经随访4～20个月全部疗效满意,捏握功能明显改善。术后3个月时恢复至S3＋M3以上。无血管、神经或屈肌腱损伤等并发症。结论：两点单侧钩切法操作步骤简单,是一种有效的手术方法。     

Basal joint arthroplasty and carpal tunnel release through a single incision: an in vitro study

PURPOSE: Carpal tunnel syndrome coexists with basal joint arthritis in a large percentage of patients. These 2 conditions are often treated surgically through separate incisions. The purpose of this cadaver study is to show the effect of trapeziectomy and transverse carpal ligament release from the scaphoid tubercle on carpal canal pressures. This technique may permit both problems to be addressed through the same Wagner incision. METHODS: In 4 fresh frozen cadaver limbs pressures in the carpal canal were elevated to 30 mm Hg through a percutaneously placed balloon. Pressures were measured using an 18-gauge sideport needle via a transducer. Trapeziectomy and release of the transverse carpal ligament from the scaphoid were performed in succession through a Wagner incision with canal pressures measured after each step. RESULTS: Carpal canal pressures decreased after trapeziectomy (mean, 7 mm Hg; range, 3-14 mm Hg) but did not return to baseline (0 mm Hg) until complete release of the ligament. CONCLUSIONS: Decompression of the carpal tunnel can be performed effectively through a Wagner incision during basal joint arthroplasty. This cadaver model shows reduction in the canal pressures after trapeziectomy and release of the transverse carpal ligament. This single-incision approach is attractive because it may decrease morbidity compared with a 2-incision approach in patients with concomitant carpal tunnel syndrome and basal joint arthritis.     

Acute carpal tunnel syndrome due to a hemangioma of the median nerve

Hemangioma of the median nerve presenting as acute carpal tunnel syndrome is unusual A-18- year old male presented with severe incapacitating pain of sudden onset of left forearm and hand after manual field work. There was swelling on volar aspect of forearm, with hyperalgesia in the median nerve distribution. The fingers and wrist were inmarked flexion and the patient did not allow wrist and finger extension. X-rays were within normal limits. An emergency volar carpal ligament release revealed, haematoma about 100 ml with numerous vessels encircling the median nerve. Histopathology of lesion turned out to be a cavernous hemangioma. Post operatively patient had full recovery.     

The use of ultrasound imaging to demonstrate reduced movement of the median nerve during wrist flexion in patients with non-specific arm pain

Following clinical screening, we examined movement of the median nerve at the wrist using high-resolution (10-22 MHz) ultrasound in 16 controls and 12 patients with non-specific arm pain (also referred to as repetitive strain injury). Imaging was performed just proximal to the carpal tunnel with the wrist in neutral, 30 degrees of extension and 30 degrees of flexion. In control subjects the position of the median nerve was 4.8 (SE=0.4) mm more radial with the wrist flexed than with the wrist extended. In the twelve arm pain patients the average change was only 1.2 (SE=0.5) mm. It appears that ultrasound imaging may be helpful in diagnosing non-specific arm pain, a condition for which there are no well-defined diagnostic tests at present. The reduced nerve movement seen with ultrasound imaging confirms previous work with magnetic resonance imaging.     

Intraoperative assessment of median nerve blood flow during carpal tunnel release with laser Doppler flowmetry

Eleven consecutive median nerves in patients with clinical carpal tunnel syndrome were examined prospectively with laser Doppler flowmetry. All procedures were done without a tourniquet with the patient under local or general anesthesia. Multiple measurements of median nerve blood flow were obtained during carpal tunnel release. Flow characteristics proximal to the transverse carpal ligament did not change after release of the ligament. Beneath the transverse carpal ligament, initial flow was random in 10 of 11 nerves. Within 1 minute after release of the transverse carpal ligament, flow became pulsatile and synchronized with the patient's pulse in nine nerves. Although preliminary, these data suggest that in carpal tunnel syndrome the segment of median nerve beneath the carpal ligament is relatively ischemic and this ischemia may be a factor in the development of symptomatic median nerve entrapment. The rapid return of a pulsatile signal within the nerve after release is positively correlated with relief or improvement of median nerve dysesthesias.     

Practical anatomy of the carpal tunnel

The carpal tunnel is most narrow at the level of the hook of the hamate. The median nerve is the most superficial structure. It has specific relationships to surrounding structures within the carpal tunnel to the ulnar bursa, flexor tendons, and endoscopic devices placed inside the canal. The importance of the ring finger axis is stressed. Knowledge of topographical landmarks that mark the borders of the carpal tunnel, the hook of the hamate, superficial arch, and thenar branch of the median nerve ensure appropriate incision placement for endoscopic as well as open carpal tunnel release surgery. Anatomy of the transverse carpal ligament, its layers and relationships to adjacent structures including the fad pad, Guyon's canal, palmar fascia, and thenar muscles has been discussed. Fibers derived primarily from thenar muscle fascia with connections to the hypothenar muscle fascia and dorsal fascia of the palmaris brevis form a separate fascial layer directly palmar to the TCL and can be retained. This helps to preserve postoperative pinch strength. The fat pad in line with the ring finger axis overlaps the deep surface of the distal edge of the TCL and must be retracted in order to visualize the distal end of the ligament. Whereas the ulnar artery within Guyon's canal is frequently located radial to the hook of the hamate, injury to this structure has not been a problem during ECTR surgery. Variations of the median nerve and its branches, as well as the palmar cutaneous nerve distribution, have been reviewed. A rare ulnar-sided thenar branch from the median nerve, interconnecting branches between the ulnar and median nerves located just distal to the end of the TCL, and transverse ulnar-based cutaneous nerves can be injured during open or ECTR surgery. Anomalous muscles, tendons or interconnections, and the lumbricals during finger flexion may be seen within the carpal tunnel. These structures can be the cause of compression of the median nerve. The anatomy of the carpal tunnel and surrounding structures have been reviewed with emphasis on clinical applications to endoscopic and open carpal tunnel surgery. A thorough knowledge of the anatomy of the carpal tunnel is essential in order to avoid complications and to ensure optimal patient outcome. An understanding of the contents and their positions and relationships to each other allows the surgeon to perform a correct approach and accurately identify structures during procedures at or near the carpal tunnel.     

Carpal tunnel changes and median nerve compression during wrist flexion and extension seen by magnetic resonance imaging

Magnetic resonance imaging was done on the wrists of 14 volunteer subjects with the wrists in the neutral position, then flexed and extended at 45 degrees. Computer enhanced cross-sectional areas were measured on each subject at the level of the hook of the hamate. In the neutral position the distance between confining structures around the median nerve is 2.0 +/- 0.2 mm in the anteroposterior direction, and the mean cross-sectional area of the carpal tunnel is 1.52 cm2. With the wrist in the extended position the distance available for the median nerve measures 2.2 +/- 0.4 mm and the cross-sectional area increases to 1.75 cm2. When the wrist is flexed, the distance available for the median nerve between the flexor tendons and transverse carpal ligament decreases to 1.1 +/- 0.4 mm, and the cross-sectional tunnel area decreases to 1.36 cm2. Flexion of the wrist and/or fingers both produces a palmar rearrangement of the flexor tendons creating potential compression of the median nerve. The nerve responds to these forces by becoming interposed in various positions between the superficial flexor tendons.     

Effects of increased systemic blood pressure on the tissue fluid pressure threshold of peripheral nerve

This study was designed to evaluate the functional response of the median nerve at the wrist to various degrees of acute, local compression in hypertensive patients. After measuring resting tissue fluid pressure in the carpal tunnel of the nondominant hand of nine subjects (diastolic pressures of 90 mm Hg or greater), localized pressures of 50, 60, or 70 mm Hg were applied to the palmar aspect of the wrist. Motor and sensory latencies and amplitudes of the median nerve were evaluated before compression, during 30–240 min of compression, and during the postcompression recovery phase. Sensory responses were completely blocked at a threshold tissue fluid pressure of 60–70 mm Hg, measured by the wick catheter technique. This pressure threshold was greater than the 40–50 mm Hg previously found in normotensive subjects. The tissue pressure threshold of normotensive and hypertensive subjects was consistently 30 mm Hg below diastolic blood pressure (approximately 45 mm Hg below mean arterial blood pressure). These results support the concept that ischemia is the prime mechanism of conduction block in low pressure, nerve-compression syndromes.     

Longitudinal sliding of the median nerve in patients with carpal tunnel syndrome

In nerve compression syndromes restricted nerve sliding may lead to increased strain, possibly contributing to symptoms. Ultrasound was used to examine longitudinal median nerve sliding in 17 carpal tunnel syndrome patients and 19 controls during metacarpophalangeal joint movement. Longitudinal movement in the forearm averaged 2.62 mm in controls and was not significantly reduced in carpal tunnel syndrome (CTS) patients (mean=2.20 mm). In contrast, CTS patients had a 40% reduction in transverse nerve movement at the wrist on the most, compared to least, affected side and nerve areas were enlarged by 34%. Normal longitudinal sliding in the patients indicates that nerve strain is not increased and will not contribute to symptoms.     

Postoperative morphologic analysis of carpal tunnel syndrome using high-resolution ultrasonography

The authors evaluated the morphologic changes that follow division of the transverse carpal ligament in patients with carpal tunnel syndrome (CTS) using high-resolution ultrasonography. Ten patients, for a total of 20 hands, underwent high-resolution ultrasonographic studies before the operation and 8 months after the operation. They were all diagnosed with bilateral idiopathic CTS. The authors evaluated the configuration of the median nerve and carpal tunnel at 3 different levels of the wrist: the distal radiocarpal joint level, the pisiform level, and the hook of hamate level. The median nerve gained in thickness to a remarkable extent at 2 distal levels after the operation. The change in morphology of the carpal tunnel at these 2 distal levels was obvious, but the cross-sectional area of the carpal tunnel was increased significantly only at the hook of hamate level. The transverse diameters of the carpal tunnel were not significantly changed. As mentioned, the authors found that the median nerve gained significantly in volume at the distal part of the carpal tunnel postoperatively, and the volumetric increase in the carpal tunnel appears to have resulted from an anterior displacement of newly formed transverse carpal ligament, rather than from a widening of the bony carpal arch.     

Measurement of pressure in the carpal canal before and after endoscopic management of carpal tunnel syndrome

In forty-six patients who had carpal tunnel syndrome, a technique of continuous infusion, given under local anesthesia and without a pneumatic tourniquet, was used to measure pressures in the carpal canal before and after endoscopic release of the transverse carpal ligament (retinaculum flexorum manus). Pressures were similarly measured in sixteen subjects in a control group. The mean preoperative pressures were significantly higher in the patients who had carpal tunnel syndrome than in the patients in the control group when the pressures were measured under four conditions: with the wrist in the resting position, with active grip, and with maximum passive extension and flexion of the wrist. The mean pressures improved significantly postoperatively and were in the range of values that were found under each condition for the control group. Measurement of pressure in the carpal canal before and after operation may be useful in diagnosing carpal tunnel syndrome and in determining the effectiveness of endoscopic management.     

内窥镜下松解腕管综合征的神经并发症

目的 报道内窥镜治疗腕管综合征时引起神经损伤的原因。方法 1997年至2003年，应用内窥镜治疗腕管综合征136例。对其中2例在内窥镜术后发生并发症的患者，在直视下再次进行手术探查，以明确神经损伤的部位及性质，并探讨引起神经损伤的原因。结果 1例正中神经在腕管内与腕横韧带粘连，在切断腕横韧带时同时损伤相连的正中神经外膜与部分束膜。经神经外膜松解后症状缓解。另1例正中神经掌皮支起始部发生变异，在内窥镜插入腕上切口处，直接损伤该皮支；经神经松解后症状缓解。结论 内窥镜治疗腕管综合征，通常是安全有效的。但在解剖变异及内窥镜下手术有困难时，易发生神经损伤，再次进行手术松解，症状缓解。     

Intraoperative measurement of pressure adjacent to the ulnar nerve in patients with cubital tunnel syndrome

PURPOSE: Little is known about whether the pressure adjacent to the ulnar nerve actually is increased in patients with cubital tunnel syndrome or if it is a causative factor. We measured the pressure adjacent to the ulnar nerve in patients with cubital tunnel syndrome during surgery and verified whether or not there was an association with patient age, duration of the disease, motor nerve conduction velocity, and severity of the ulnar nerve neuropathy. METHODS: Eight elbows in 8 patients with an average age of 62 years were treated surgically and the extraneural pressures within the cubital tunnel were measured during surgery by using a fiberoptic microtransducer. Pressure was measured 3 times with the elbow fully extended and then 3 times with the elbow flexed 130 degrees. The transducers were placed at 1, 2, and 3 cm distal to the proximal edge of the Osborne ligament. The severity of the neuropathy was evaluated according to Akahori's classification. The ulnar nerve palsy was graded as stage III in 5 patients and as stage IV in 3 patients. RESULTS: The average pressures within the cubital tunnel at 1, 2, and 3 cm distal to the proximal edge of the cubital tunnel retinaculum with the elbow flexed were 105, 29, and 18 mm Hg, respectively. The pressures at 1 and 2 cm distal to the proximal edge of the cubital tunnel retinaculum were significantly higher in elbow flexion than in elbow extension. There was also a positive correlation between the pressure and patient age but this was not significant The pressures correlated significantly with the stage of ulnar nerve neuropathy, motor nerve conduction velocity, and disease duration. CONCLUSIONS: The extraneural pressure within the cubital tunnel actually was increased in the patients and compression of the ulnar nerve might be a causative factor of cubital tunnel syndrome.     

Transverse carpal ligament reconstruction in surgery for carpal tunnel syndrome: a new technique

We present a two-year follow-up of a technique to reconstruct the transverse carpal ligament in surgery for carpal tunnel syndrome. The transverse carpal ligament is exposed through a four to five centimeter palmar incision in line with the axis of the ring finger. The ligament is divided in step-wise fashion, creating a distal radially-based flap and a proximal ulnarly-based flap. The apices of these flaps are approximated, lengthening the ligament six to ten millimeters. All seventy-three patients (one hundred-four hands) reported substantial improvement with 93% having complete resolution of symptoms. Ninety-seven percent returned to work (average disability, two months). There were no recurrences or significant operative complications. In those with unilateral reconstruction (60%), there was no diminution in grip strength (p less than 0.05). This technique of transverse carpal ligament reconstruction stabilizes the transverse carpal arch, provides protection to the median nerve, prevents bowstringing of the flexor tendons, and maximizes postoperative grip strength.     

Carpal tunnel pressures and wrist position in patients with colles' fractures

Intracarpal canal interstitial fluid pressures were determined in the wrists of 22 patients with 23 Colles' fractures. Mean values were 18 mm Hg in neutral wrist position, 27 mm Hg in 20 degrees flexion, 47 mm Hg in 40 degrees flexion, and 35 mm Hg in 20 degrees extension. Ten of 23 wrists (45%) had pressures greater than 40 mm Hg in 40 degrees of flexion. Because of the high incidence of median neuropathy associated with immobilization of wrist fractures in a position of marked flexion, an awareness of the magnitude of increased interstitial fluid pressure should lead to alternative methods of treatment in many cases.