Ulnar subluxation of the median nerve following carpal tunnel release: a case report

Complications of carpal tunnel release, while infrequent, include incomplete release resulting in persistent symptoms or recurrence due to postoperative scarring, as well as iatrogenic damage to nerves and vessels. We present the case of a patient who underwent carpal tunnel release with resolution of symptoms in the immediate postoperative period. At one and a half years post release he started to experience numbness and tingling in a median nerve distribution triggered by repetitive ulnar to radial deviation of the wrist, with no symptoms at rest. Dynamic ultrasound showed a subluxation of the median nerve from one side of the palmaris longus tendon to the other. The patient's symptoms were triggered as the median nerve squeezed in between the palmaris longus and flexor digitorum superficialis tendons.     

Median and ulnar nerve compression at the wrist caused by anomalous muscles

Compression of the median and ulnar nerves at the wrist is frequently encountered. Carpal tunnel syndrome usually occurs without any obvious extrinsic cause; several cases have however been reported caused by anomalous or hypertrophic muscles. A survey of the literature shows that compression neuropathy of the median nerve has been reported in relation with anomalies affecting three muscles: the first (or second) lumbrical, the palmaris longus and its anatomic variants and the superficial flexor of the index finger. In the ulnar tunnel the situation is thoroughly different: so-called idiopathic ulnar tunnel syndrome is rare and an extrinsic compressing structure can usually be disclosed. Anomalous muscles belong to the palmaris longus/abductor digiti minimi group; the flexor carpi ulnaris is sometimes involved. One can suspect the presence of such an anomalous muscle when the compression syndrome concerns a patient who is not within the "usual" age group with symptoms initiated or aggravated by physical exercise.     

Bilateral palmaris profundus causing bilateral carpal tunnel syndrome

Only a few cases of palmaris profundus have been reported in the English-language literature. The palmaris profundus is a rare anomalous muscle of the forearm that may cause carpal tunnel syndrome. We describe the first case of bilateral palmaris profundus associated with bilateral palmaris longus causing bilateral carpal tunnel syndrome.     

Median nerve compression by a radially inserted palmaris longus tendon after release of the antebrachial fascia: A complication of carpal tunnel release

We describe a case that had recurrent median nerve compression after release of the antebrachial fascia in carpal tunnel release. The nerve was compressed by a palmaris longus tendon that was inserted radially into the thenar fascia. After decompression (detachment of the tendon) the patient had symptom relief. Release of the antebrachial fascia in the presence of this tendon variant carries a risk of median nerve compression by the tendon.     

Ulnar nerve compression caused by a reversed palmaris longus muscle

A case of ulnar nerve compression at the wrist caused by a reversed palmaris longus muscle is reported. We are not aware of any previous reports of ulnar nerve compression due to this particular muscle anomaly.     

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.     

Median innervated hypothenar muscle: anomalous branch of median nerve in the carpal tunnel

A hypothenar motor branch of the median nerve in the carpal tunnel was observed and its motor function was documented by direct intraoperative nerve stimulation in two patients having carpal tunnel releases. The hypothenar branch left the median nerve at the midcarpal tunnel area. It crossed the tunnel superficial to the flexor tendons and penetrated the transverse carpal ligament ulnarly to innervate the abductor digiti quinti. Such branching of the median nerve at this level has not been reported previously. Good visualization of the carpal tunnel and careful dissection of its content even in the so called safe zone ulnar to long axis of palmaris longus tendon is recommended.     

Distal rupture of the palmaris longus tendon and fascia as a cause of acute carpal tunnel syndrome

Acute carpal tunnel syndrome is rare compared with its more chronic presentation. Previous reports in the literature have documented the most common causes. Rupture of the distal palmaris longus tendon into the palmaris fascia as a cause of an acute carpal tunnel syndrome has not been reported previous to this case report. Partial rupture of the tendon and hemorrhage around its insertion produced intrinsic compression on the transverse ligament and the underlying nerve.     

Palmaris longus transfer for replacement of the first dorsal interosseous

Using palmaris longus, the first dorsal interosseous was reconstructed without free tendon graft. Palmaris longus prolonged with a strip of palmar fascia was transferred rectilinearly to the site of insertion of the first dorsal interosseous via a subcutaneous tunnel and fixed. This method was applied to seven hands of six patients and the follow-up observation continued for more than six months postoperatively. In six hands, favourable stability and abduction function of the index finger was achieved. In one hand, adhesion occurred at the site of the first dorsal interosseous muscle resulting in tenodesis. This operative method appears to be useful in the reconstruction of the first dorsal interosseous muscle from non-recovering paralysis following injury of the first dorsal interosseous muscle, or ulnar nerve. This method may also be utilized after decompression of chronic compression of the ulnar nerve giving no expectation of complete recovery by the reconstruction and augmentation of the first dorsal interosseous muscle. No unpleasant side effect was encountered.     

腕管综合征内窥镜手术预防正中神经损伤的临床研究

目的 介绍腕管综合征内窥镜手术(endoscopic carpal tunnel release,ECTR)预防正中神经损伤并发症的方法.方法 利用彩色多普勒超声仪(B超)对37例74手患者术前进行检测.结果 71例正中神经走行在桡侧腕屈肌腱与掌长肌腱之间,3例走行在掌长肌腱与尺侧腕屈肌腱之间,并术中确认.结论 正中神经变异走行在掌长肌腱与尺侧腕屈肌腱之间是ECTR的禁忌证,B超能准确定位正中神经与掌长肌腱关系,避免内窥镜手术损伤正中神经,更具有简单、经济、方便可靠等优点.

Abstract：

Objective To introduce a method of preventing median never injury during endoscopic carpal tunnel release (ECTR). Methods Ultrasonography of both wrists was done to 37 patients of carpal tunnel syndrome who were going to undergo open release of the transverse carpal ligament. Structures in the carpal tunnel were visualized to guide surgical decision-making. Results Ultrasonography showed that median never lies between the tendon of flexor carpi radialis and palmaris longus in 71 patients and lies between the tendon of palmaris longus and flexor carpi ulnaris in 3 patients. These findings were confirmed during the surgeries. Conclusion It is a contraindication of ECTR if median never lies between palmaris longus and flexor carpi ulnaris. Ultrasonography can accurately reveal the relative position of median never to the palmaris longus tendon. Pre-operative ultrasonography of the wrist is a simple, inexpensive and convenient method to exclude these contraindications and thus prevent median never injuries in ECTR.     

A reliable technique for avoiding the median nerve during carpal tunnel injections

Carpal tunnel injections are widely performed for diagnostic and therapeutic purposes. Injury to the median nerve is a serious and fairly common complication. There is no consensus regarding the safest injection site. The objective of this study was to determine the safest injection site based on anatomical data. During 124 endoscopic procedures for median nerve release at the carpal tunnel, we measured the distances separating the median nerve, palmaris longus (PL), flexor carpi radialis (FCR), and flexor carpi ulnaris 1 cm proximal to the wrist crease. The edge of the median nerve extended medially beyond the PL tendon in 82 (88%) hands. Thus, needle insertion within 1 cm of either edge of the PL tendon may cause median nerve injury; with injection sites located further toward the medial edge, the ulnar pedicle may be at risk. Consequently, we recommend that carpal tunnel injections be performed through the FCR tendon.     

Anatomy of the flexor retinaculum of the wrist and the flexor carpi radialis tunnel

The flexor retinaculum forms a retinacular bridge over the carpal tunnel extending from ulnar to radial direction. Its main function is to protect the contained without a significant mechanical action in supporting the transverse carpal arch. The osteofibrous tunnel of flexor carpi radialis is independent and presents four sections. The palmaris longus tendon presents a distal insertion forming the superficial layer of the aponeurosis palmaris. The flexor carpi ulnaris tendon has four distal insertions.     

Effort-related compression of median and ulnar nerves as a result of reversed three-headed and hypertrophied palmaris longus muscle with extension of Guyon's canal.

We explored a swelling on the anterior surface of the right distal forearm of a 21-year-old right-handed male soldier and effort-induced symptoms of median and ulnar nerve compression that showed a reversed, three-headed and hypertrophied palmaris longus muscle with extension of Guyon's canal.     

The clinical significance of the palmaris longus tendon in the pathophysiology of carpal tunnel syndrome

Carpal tunnel syndrome is associated with increased intracarpal canal pressure. The effect of tendon loading on intracarpal canal pressures is documented in biomechanical studies. Palmaris longus loading in wrist extension induces the greatest absolute increase in intracarpal canal pressure. Despite this fact, the palmaris longus is not yet a proven independent risk factor for the development of carpal tunnel syndrome. The purpose of this prospective clinical study was to assess and quantify the association between the presence of a palmaris longus tendon and carpal tunnel syndrome. Thirty-six carpal tunnel subjects with bilateral disease were compared with 36 controls. Each subject was clinically examined for the presence of the palmaris longus tendon. The prevalence of palmaris longus agenesis was significantly lower in the carpal tunnel group. The palmaris longus tendon is a strong independent risk factor for carpal tunnel syndrome.     

Prevalence of anatomic variations encountered in elective carpal tunnel release

PURPOSE: To determine the prevalence of aberrant or unexpected anatomic structures within one surgeon's elective experience of carpal tunnel releases and their association with pathologic compression. METHODS: A total of 31 anomalies of median nerve, muscle, and tendon, median artery persistence, and ulnar nerve were documented in 30 hands during the course of 526 elective carpal tunnel releases in one surgeon's practice. The data collected were reviewed retrospectively. All carpal tunnel releases were performed open, exposing the median nerve from the palmar arch to the proximal wrist crease. Anomalies were categorized into those involving the median nerve and its motor and sensory branches, the ulnar nerve, a persistent median artery, and anomalies of muscle/tendon units traversing the carpal tunnel area. RESULTS: Seven hands were noted to have aberrant muscle/tendon variations within the carpal tunnel region (1.3%). Anomalies of the median nerve or its palmar cutaneous or motor branches were observed in 5 hands (1.0%). An anomaly of the ulnar nerve with an aberrant branch crossing the carpal tunnel incision occurred in one hand. A persistent median artery (>or=1 mm) was noted in 18 hands (3.4%). One hand had 2 anomalies present. One anomaly was high bifurcation of the median nerve and the second anomaly was an anomalous muscle to the long finger superficialis. CONCLUSIONS: The specific anatomic variations described may be anticipated and more readily recognized by hand surgeons during such open surgery, thus increasing the efficacy and safety of this common procedure.     

Anomalous flexor digitorum superficialis muscle transposition for vascular coverage of the median nerve in recurrent carpal tunnel syndrome

Recurrent carpal tunnel syndrome is uncommon yet troublesome. Significant adhesions and scarring around the median nerve can render it relatively ischemic. A number of vascular flaps have been described to provide vascular coverage in attempts to decrease further cicatricial adhesions and to improve local blood supply around the median nerve. A rare case of an anomalous muscle in the distal forearm used as tissue to provide good vascularized coverage of the median nerve that was severely scarred in its bed is reported. The anomalous muscle was distal to the flexor digitorum superficialis tendon and inserted in the palmar fascia on the ulnar aspect of the hand. Referring branches from the ulnar artery provided vascular supply to the anomalous muscle. The muscle on these vascular pedicles was transposed over the median nerve, providing good, stable, unscarred coverage. The patient had an excellent result with resolution of the carpal tunnel symptoms. The redundant anomalous muscle provided a unique vascularized source for coverage of the median nerve in recurrent carpal tunnel syndrome.     

Ulnar nerve palsy after open carpal tunnel decompression: Case report and review of the literature

Open carpal tunnel release is the commonest surgical treatment of median nerve compression at the wrist. Although successful in most cases, there are well described complications. We report a case of laceration of the deep motor branch of the ulnar nerve at the level of the hook of hamate following a complicated carpal tunnel decompression. Good surgical technique and knowledge of wrist anatomy are essential for performing this apparently simple procedure safely.     

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.     

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.     

Anomalous palmaris longus muscle causing carpal tunnel-like syndrome

A case of median nerve compression due to an anomalous fleshy palmaris longus muscle in a patient with mild Volkmann ischemic contracture is presented. Received: 27 June 1995