Entrapment neuropathy of the palmar cutaneous branch of the median nerve concomitant with carpal tunnel syndrome: a case report

A case of the entrapment neuropathy of the palmar cutaneous branch of the median nerve, concomitant with carpal tunnel syndrome is presented. This report demonstrates that the Semmes-Weinstein monofilament test and nerve conduction studies can identify entrapment of the palmar cutaneous branch of the median nerve concomitant with carpal tunnel syndrome.     

Safety of carpal tunnel release with a short incision. A cadaver study

The standard long incision technique for carpal tunnel release causes inevitable damage to skin sensation, the inter-thenar plexus and especially the distal branches of the palmar cutaneous branch of the median nerve (PCM), and may cause long-term disabling pain and scar tenderness. There are many variations in the distal branches of the median nerve at the wrist. Anatomic studies of this region also have important clinical implications to prevent injury to important anatomic structures. The purpose of this study was to evaluate the short-incision carpal tunnel release in cadavers. Several important anatomic structures, with possible anatomic variations, pass through the carpal tunnel, and blind percutaneous transection of the transverse ligament seems to be a high risk procedure. Sixty hands from 40 fresh cadavers were evaluated. Both the transverse ligament and the distal third of the deep forearm fascia were released using a Smillie knife. At the end of each procedure, the hand was explored for injury to tendinous and neurovascular structures of the wrist. In all cases the release of the carpal tunnel and the distal third of the forearm fascia was found to be complete. The superficial palmar arterial arch, flexor tendons, ulnar nerve and vessels, digital nerves, median nerve and its recurrent accessory branches, the flexor tendons, and even the subcutaneous tissue over the transverse ligament were damaged in no instance. Guyon's canal was entered in 6 (10%) hands without damage to its components. The distal branches from the ulnar side of the palmar cutaneous branch of the median nerve (PCM) were injured in 8 (13.6%) hands, an injury that is almost unavoidable with the classic open technique.     

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.     

Anatomical study of the pre-retinacular fat pad of the wrist: application to a new surgical approach to the carpal tunnel

INTRODUCTION: Decompression of the median nerve in the carpal tunnel by section of the flexor retinaculum is the generally accepted treatment for carpal tunnel syndrome and is usually effective in relieving the symptoms. Following postoperative observations we proposed the hypothesis that incisional pain following open carpal tunnel release could be partly explained by injury to the fat pad situated between the palmar carpal ligament and the flexor retinaculum. METHOD: We performed an anatomical study on 20 fresh adult latex injected upper limbs. RESULTS: The sus-retinacularis fat pad is a real anatomical structure, clearly delineated and located inside a defined fibrous space with its own innervation from the ulnar nerve. It lies in the path of the normal carpal tunnel approach. DISCUSSION: Although most postoperative scar tenderness is attributed to neuroma formation because of injury to transverse branches of the palmar cutaneous nerves, we nevertheless consider that injury to the preretinacular fat pad also plays a part. We propose a modified approach to the carpal tunnel. This is a safe and simple method which respects the integrity of the sus-retinacularis fat pad so as to minimise the extent of scar tenderness.     

Mini-open carpal tunnel decompression

Carpal tunnel syndrome is the most common entrapment neuropathy, and it is caused by compression of the median nerve at the wrist. The authors describe the mini-open carpal tunnel technique for surgical release of the transverse carpal ligament. The success of the procedure depends on meticulous technique with attention to certain important anatomic details and careful avoidance of injury to the palmar cutaneous nerve and the recurrent motor branch.     

Double incision for operation of carpal tunnel syndrome--14 years experience]

15 years ago I started to do the surgical release of carpal tunnel syndrome by the "double incision technique", avoiding the postoperative tenderness in the so called carpal barrier. The postoperative results of 293 operations prove the small morbidity, the short inability for work, the small loss of strength and the few postoperative complications. The danger of this very well tolerated method is that the extend of the ulnar artery, the motor branch and the palmar cutaneous branch of the median nerve may be abnormal and the mentioned structures may be harmed by the operation. A well trained surgeon will practice this technique with success, but it should not be applicated by beginners.     

Nerve stripping: new treatment for neuromas of the palmar cutaneous branch of the median nerve

We present a new method for the treatment of painful neuromas of the palmar cutaneous branch of the median nerve. A preliminary cadaver study was done to investigate the extraneural and intraneural course of the palmar cutaneous branch of the median nerve with respect to the main trunk of the median nerve. Seven patients presented with a painful neuroma following previous surgery on the palmar aspect of the wrist. The neuroma was dissected and excised by stripping the whole of the palmar cutaneous branch from the main trunk of the median nerve. In all cases complete relief from pain and discomfort was achieved. The resulting area of numbness in the palm did not represent a significant problem.     

Isolated compression neuropathy of the palmar cutaneous branch of the median nerve

A case of isolated thenar numbness, with an associated painful palmar wrist mass is presented. At operation, a palmar wrist ganglion compressing the palmar cutaneous branch of the median nerve was encountered. After ganglion excision the numbness in the palm was relieved, and there was no recurrence at 6 years follow-up.     

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.     

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。     

Carpal tunnel release under local anesthesia: evaluation of the outpatient procedure

In 100 consecutive cases of carpal tunnel release done under local anesthesia in an outpatient ambulatory care operating room, 93 had satisfactory results at 6 months without any complications. Two patients developed a neuroma of the palmar cutaneous branch of the median nerve, and five showed early signs of reflex sympathetic dystrophy. These complications are discussed, as well as the prevention of other complications of this procedure.     

Carpal tunnel syndrome associated with extra tunnel vascular compression of the median nerve motor branch

We report a case of carpal tunnel syndrome associated with median nerve motor branch compression by a large superficial palmar branch of the radial artery.     

Complications related to carpal tunnel release

Complications of operative carpal tunnel release continue to occur in the clinical practice of hand surgery. Anatomic localization of nerve injury has been reviewed in the area of the palmar cutaneous nerve, the median motor branch, and in the combined sensory/motor median nerve itself. Diagnosis and appropriate treatment plans have been reviewed to facilitate early appropriate treatment which usually diminishes disability. General complications have also been discussed including recurrent scar formation which is probably the most commonly encountered complication following carpal tunnel release. Possible neurovascular complications involving the development of reflex sympathetic dystrophy have received some attention in this presentation in order to alert the clinical surgeon to the possibility of this entity providing further disability to an already injured median nerve.     

Neuropraxia of the palmar cutaneous branch of the ulnar nerve during carpal tunnel decompression

Carpal tunnel syndrome is one of the most commonly encountered conditions in the hand clinic and carpal tunnel decompression is the most frequently performed procedure in hand surgery. It is an effective procedure for patients with carpal tunnel syndrome. However, there is a high risk of complications that can be avoided with an understanding of wrist anatomy, appropriate planning and execution. We highlight one such complication, a case of neuropraxia of the palmar cutaneous branch of the ulnar nerve that followed carpal tunnel decompression.     

Median nerve compression in the palm of the hand by an anomalously enlarged ulnar artery

Median nerve compression in the carpal tunnel by a thrombosed persistent median artery and a large aberrant artery substituting for the radial artery has been described but there have been no reports of median nerve compression in the palm of the hand by an anomalously enlarged ulnar artery. A 46 year old man is described who presented with clinical and electrophysiological features consistent with a median neuropathy at the wrist but surgical exploration revealed median nerve compression in the palm of the hand by an anomalously enlarged palmar branch of the ulnar artery. This case highlights another treatable cause of median nerve compression and illustrates that symptoms suggestive of carpal tunnel syndrome may be produced by median nerve compression in the palm of the hand.     

Thenar eminence quantitative sensory testing in the diagnosis of proximal median nerve compression.

Diagnosis of proximal median nerve compression (PMNC) remains a clinical challenge. The authors hypothesized that measurement of the sensibility of the thenar eminence might identify PMNC by demonstrating abnormal function in the palmar cutaneous branch of the median nerve. This hypothesis was evaluated by means of quantitative sensory testing of the thenar eminence in 33 healthy volunteers, 14 patients with carpal tunnel syndrome, and 35 patients with PMNC. The cutaneous pressure thresholds for one-point static touch (1PS) and two-point static touch (2PS) were measured with the Pressure-specified Sensory Device (Sensory Management Services, Baltimore, Maryland). There was no significant difference in thenar eminence sensibility between the healthy volunteers and the patients with carpal tunnel syndrome. In contrast, patients with PMNC had higher cutaneous pressure thresholds for 1PS (p<0.001), 2PS-pressure (p<0.001), and 2PS-distance (p<0.001) than did patients with carpal tunnel syndrome. The p values were less than 0.001 for each of these three comparisons between the healthy volunteers and the patients with PMNC. For the diagnosis of PMNC, quantitative sensory testing of the thenar eminence has a sensitivity of 90.3%, a specificity of 83.3%, and a positive predictive value of 87.5%.     

Long-term outcome after carpal tunnel decompression - a prospective randomised study of the Indiana Tome and a standard limited palmar incision

This randomised trial compared the results of carpal tunnel decompression using the TM Indiana Tome (Biomet, Warsaw, Indiana, USA) and a standard limited palmar open incision. Two hundred patients were randomly selected to have a carpal tunnel decompression with either the Indiana Tome or a limited palmar technique. They were assessed clinically for 3 months and using the Levine-Katz self-assessment evaluation for 7 years. After 7 years, there were 62 returned questionnaires from the open group and 53 from the Tome group. There were no significant differences in functional scores, pain, scar tenderness, pinch and grip strength at 3 months. There were two complications in the open group and nine in the Tome group, including one median nerve injury. There was both a higher rate of immediate complications, and more recurrences and persisting symptoms at 7 years in the Indiana Tome group.     

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.     

腕关节神经支配的解剖学研究

目的观察支配腕关节神经的来源、直径、数目及其行径;为去神经支配治疗腕关节疼痛提供解剖学资料。方法对10具20侧福马林固定的上肢标本,在手术显微镜下解剖并观察骨间后神经、前臂外侧皮神经、桡神经浅支、尺神经腕背支支配腕关节背侧的腕关节支;骨间前神经、正中神经掌皮支、尺神经深支及其主干支配腕关节掌侧的关节支。结果骨间后神经是支配腕关节背侧神经的主要来源;前臂外侧皮神经、桡神经浅支、尺神经腕背支也发支支配腕关节背侧。骨间前神经、正中神经掌皮支、尺神经深支发支参与支配腕关节的掌侧。结论用去神经支配的方法治疗腕关节顽固性疼痛主要适用于腕背侧的疼痛。     

Palmar cutaneous branch of the median nerve

The palmar cutaneous branch of the median nerve was dissected in 25 fresh cadavers. The origin from the median nerve, the course, termination, and variability of the palmar cutaneous nerve are described in relation to two reference lines. In no case did a branch of the palmar cutaneous nerve extend ulnar to the axial line of the ring finger. The planning of incisions around the palmar aspect of the palm and wrist should be based on this anatomical knowledge.