Recurrent Motor Branch Research Articles

Can palmar creases serve as landmarks for the deeper neuro-vascular structures?

Purpose The aim of this study was the examination of the superficial anatomy of palmar creases and their relation to deeper neuro-vascular structures.MethodsFour creases: distal wrist flexion crease, thenar crease, proximal palmar crease and distal palmar crease were evaluated with reference to the following structures: palmar cutaneous branch of median nerve, palmar cutaneous branch of ulnar nerve, the nerve of Henle, transverse palmar branches from ulnar nerve, recurrent motor branch of median nerve, radial proper palmar digital nerve to the index and the ulnar proper palmar digital nerve to the thumb, Berrettini’s communicating branch, ulnar nerve and artery, superficial palmar arch. We performed dissections of 20 cadaveric upper limbs derived from a homogenous Caucasian group. In our study we measured the location of surgically important structures with reference to palmar skin creases.Results Among the other observations we noticed that the palmar cutaneous branches of the median and ulnar nerves were located at least 0.5 cm away from the thenar crease. The superficial palmar arch was found between the thenar and proximal palmar crease and never crossed the proximal or distal palmar creases.ConclusionsThese anatomical dissections will provide reference material for further ultrasound studies on the arrangements of neuro-vascular structures in reference to superficial palmar creases.

Value of anatomic landmarks in carpal tunnel surgery

This study investigated which anatomic landmarks were most useful for correct and safe incision placement in carpal tunnel surgery. Kirschner wires were attached to the hands to mark previously defined landmarks. The bony attachments of the transverse carpal ligament, which were identified previously, were drawn on an anteroposterior digital x-ray of the hand, with the thumb in full abduction. The relationship between anatomic landmarks and these bony attachments were examined. In all hands, either the line along the third web space or the crease between the thenar and the hypothenar regions, or both, were on the ulnar half of the transverse carpal ligament. During incision placement, we recommend selecting the most ulnar choice between the line drawn along the third web space and the crease between the thenar and hypothenar regions in order to be at safe distance from the recurrent motor branch of the median nerve.

„Dangerous” Anatomic Varieties of Recurrent Motor Branch of Median Nerve

Carpal tunnel release became one of the most common operations in the field of hand surgery. Many controversies has been made about frequency of the so-called dangerous variations of motor branch of the median nerve. Knowledge of all the anatomical variations motor branches is the duty of every surgeon dealing with the subject. The aim of the study was to present the incidence of dangerous variants of median nerve motor branch in the carpal tunnel based on both clinical experience and anatomical studies performed on 20 cadaver wrists. Between 2006-2012 during minimally open carpal tunnel release we made photographic documentation of all visible dangerous varieties of recurrent motor branches of the median nerve. We also studied 20 cadaver wrists in the Department of Anatomy Medical University in Wrocław. Dangerous varieties of the motor branch of median nerve was found in three clinical cases and in one cadaver wrist. Also In one wrist we found one regular branche, which, however, has atypical two separate branches supplying the thenar muscles. Dangerous varieties of the motor branch of median nerve occur very rare in the population, but does not release from the fact that in each case special attention must be given.We also conclude that, at the minimally open carpal tunnel release procedure, the transverse carpal ligament should be released rather from the line of radial border of the 4th finger to minimize the risk of injury to the recurrent motor branch of median nerve.

Clinical images of the recurrent motor branch of the median nerve

Clinical images of the recurrent motor branch of the median nerve

Volar Plate Osteosynthesis of Distal Radius Fractures With Concurrent Prophylactic Carpal Tunnel Release Using a Hybrid Flexor Carpi Radialis Approach

To evaluate the safety and efficacy of a hybrid flexor carpi radialis (FCR) approach for volar plate osteosynthesis of displaced distal radius fractures with concurrent prophylactic carpal tunnel release (CTR) in patients without preoperative signs or symptoms of acute carpal tunnel syndrome secondary to the fracture. A total of 68 displaced distal radius fractures in 65 eligible adult patients (35 men, 30 women; mean age, 48.6 +/- 15.4 y) who had volar plate osteosynthesis and concomitant prophylactic CTR through a hybrid FCR approach by a single surgeon were included in this study. A systematic chart review and subsequent telephone questionnaire were performed to identify any postoperative median nerve dysfunction, recurrent motor or palmar cutaneous branch injury, tendon injury, or other complications directly related to the approach. Reported symptoms consistent with late median nerve dysfunction were identified in 2 cases; however, no patients in this series required additional surgery for early or late median neuropathy. Furthermore, no cases of median nerve sensory or motor branch injury or tendon injury were identified. No other unforeseen complications specifically related to the approach were observed. Volar plate osteosynthesis of distal radius fractures with a concurrent prophylactic CTR can be safely performed through the described hybrid FCR approach in patients without signs or symptoms of acute CTS. Routine release of the transverse carpal ligament with the hybrid FCR approach at the time of fracture fixation might reduce the incidence of postoperative median nerve dysfunction. Therapeutic IV.

Single-Incision Extensile Volar Approach to the Distal Radius and Concurrent Carpal Tunnel Release: Cadaveric Study

To determine whether a single-incision extensile approach to the distal radius used for open reduction internal fixation and a concomitant radial sided carpal tunnel (CT) release safely and effectively decompresses the carpal tunnel. Five pairs of cadaveric forearms were mounted to a tabletop with a cable pulley system attached to the long finger. Each paired specimen was randomized to volar plating via either the flexor carpi radialis approach (control group) or the extensile volar exposure (combined flexor carpi radialis and radial-sided carpal tunnel release). Before and after the respective exposure and plating, increased CT pressures were created with 2.27, 4.54, and 6.81 kg of distraction. We used a paired t-test to compare the change in CT pressure at each level of distraction before and after intervention for the 2 groups, with significance set at p </= .05. A dissection of each exposure was performed with attention given to the radial aspect of the transverse carpal ligament (TCL) and any possible iatrogenic injuries. Carpal tunnel pressure increased with increasing distraction. We noted a statistically significant reduction in CT pressure after the extensile exposure and plating with 4.54 (p = .023) and 6.81 (p < .001) kg of distraction, respectively. No significant reduction in mean CT pressure for the control group specimens occurred at any level of distraction force. The average length of the radial TCL was 22 mm (range, 18-31 mm); the average distance between the recurrent motor branch and distal TCL was 11 mm (range, 8-15 mm). No iatrogenic tendon or nerve injury occurred with the extensile volar exposure. Carpal tunnel pressure is safely reduced and the distal radius is adequately exposed for fixation with the extensile volar approach.

Mini Open Carpal Tunnel Release Using Knifelight(R): Evaluation of the Safety and Effectiveness of Using a Single Wrist Incision (Cadaveric Study)

This cadaveric study evaluates the margin of safety and technical efficacy of mini open carpal tunnel release performed using Knifelight® (Stryker Instruments) through a transverse 1 cm wrist incision. A single investigator released 32 wrists in 17 cadavers. The wrists were then explored to assess the completeness of release and damage to vital structures including the superficial palmar arch, palmar cutaneous branch and recurrent branch of the median nerve. All the releases were complete and no injury to the median nerve and other structures were observed. The mean distance of the recurrent motor branch to the ligamentous divisions was 5.7 ± 2.4 mm, superficial palmar arch was 8.7 ± 3.1 mm and palmar cutaneous branch to the ligamentous division was 7.2 ± 2.4 mm. The mean length of the transverse carpal ligament was 29.3 ± 3.7 mm. Guyon’s canal was preserved in all cases.

Mini Open Carpal Tunnel Release Using Knifelight®: Evaluation of the Safety and Effectiveness of Using a Single Wrist Incision (Cadaveric Study)

This cadaveric study evaluates the margin of safety and technical efficacy of mini open carpal tunnel release performed using Knifelight (Stryker Instruments) through a transverse 1 cm wrist incision. A single investigator released 32 wrists in 17 cadavers. The wrists were then explored to assess the completeness of release and damage to vital structures including the superficial palmar arch, palmar cutaneous branch and recurrent branch of the median nerve. All the releases were complete and no injury to the median nerve and other structures were observed. The mean distance of the recurrent motor branch to the ligamentous divisions was 5.7 +/- 2.4 mm, superficial palmar arch was 8.7 +/- 3.1 mm and palmar cutaneous branch to the ligamentous division was 7.2 +/- 2.4 mm. The mean length of the transverse carpal ligament was 29.3 +/- 3.7 mm. Guyon's canal was preserved in all cases.

An anatomical variation of the third common digital nerve and recurrent motor branch of the median nerve

Carpal tunnel syndrome (CTS) is an entrapment neuropathy where the median nerve is compressed in the carpal canal. There are many variations of the distal branches of the median nerve at the wrist. Anatomical variations of this nerve have fundamental clinical importance to prevent injuries, especially during limited open or endoscopic surgical procedures. A case is presented of an anomalous course of the recurrent motor branch of the median nerve and high division of the third common digital nerve seen in a limited open carpal tunnel release.

Indirect Decompression of the Carpal Tunnel During Basal Joint Arthroplasty of the Thumb

In patients having basal joint arthroplasty, rates of concomitant carpal tunnel syndrome may exceed 43%. Excision of the trapezium during basal joint arthroplasty partially releases the transverse carpal ligament. The objective of this study was to determine whether indirect release of the remaining fibers of the ligament at its insertion on the scaphoid tubercle through the same incision would adequately decompress the carpal canal. This would avoid the morbidity of a second incision. We retrospectively reviewed 10 consecutive patients treated over a 2-year period who had concurrent ligament reconstruction, tendon interposition basal joint arthroplasty of the thumb with complete trapezial resection, and indirect carpal tunnel release through a single incision. Self-reported postoperative pain relief was documented. Preoperative and postoperative evaluations of light touch sensibility, Tinel's sign, Phalen's test, median nerve compression test, and Weinstein Enhanced Sensory Test monofilament testing were analyzed. All patients had preoperative electrodiagnostic testing. At mean 12 month follow-up (range, 5-35 months), numbness and paresthesias resolved in all cases: 9 patients had good or excellent pain relief and 1 reported fair pain relief despite transient postoperative reflex sympathetic dystrophy. Tinel's, Phalen's, and median nerve compression tests were each positive in 9 patients preoperatively and 0 patients postoperatively. Diminished light touch sensibility was present in 7 preoperatively and 1 postoperatively. WEST monofilament thresholds improved postoperatively in 8 patients. These improvements were statistically significant. One patient had postoperative nerve conduction studies performed to evaluate an ulnar nerve lesion at the elbow; the preoperative median nerve abnormalities had normalized. Carpal tunnel syndrome can be successfully managed with indirect release of the transverse carpal ligament during basal joint arthroplasty, thus avoiding a second incision, reducing operating time, and potentially reducing the possibility of perineural adhesions, recurrent motor branch injury, palmar cutaneous nerve damage, weakness, stiffness, and pillar pain. Therapeutic IV.

Functional gracilis flap in thenar reconstruction

Restoration of lost opposition in the context of significant thenar soft tissue defects represents a tremendous reconstructive challenge. Free functioning muscle transfer has been described in this context and has the advantage of providing both a functioning muscle unit as well as soft tissue coverage in a single reconstructive procedure. It adds to the injured limb, and by sparing donor tendons avoids the need for re-education of motor function. We describe the use of a free innervated gracilis muscle flap for functional thenar reconstruction in two unique cases following extensive traumatic loss of thenar skin and musculature. Crucially, in each case, the recurrent motor branch of the median nerve had been destroyed at its point of insertion into the thenar muscle remnants. To date, the main reported disadvantages of free functioning muscle transfer in thenar reconstruction include difficult flap dissections, donor site morbidity, inadequate strength and excursion of the transplanted muscle and excessively bulky flaps. Our aim was, as far as possible, to address these issues. Each thenar defect was measured and a corresponding segment of gracilis muscle, measured in situ, was raised on the proximal neurovascular pedicle. End-side microvascular anastomosis was performed between the medial circumflex femoral artery and the radial artery. The venae comitantes of the pedicle were anastomosed end-end with those of the radial artery and also with the cephalic vein. Epineural anastomosis was performed between the motor branch of the obturator nerve and the recurrent motor branch of the median nerve. Each flap was covered with a split thickness skin graft. Both flaps survived without any complication. Both patients regained excellent voluntary thumb opposition, sufficient to allow return to full-time employment, and had restoration of sufficient thenar bulk. This was achieved with minimal donor site morbidity. Restoration of lost opposition, in the context of significant thenar soft tissue defects, can be achieved using a free functional gracilis flap. This produces clinically excellent functional results and can be carried out as a single stage reconstructive procedure. This is a novel application of a tremendously versatile donor muscle in functioning free muscle transfer.

Isolated Fascial Compression of the Recurrent Motor Branch of the Median Nerve: A Case Report

Isolated compression of the recurrent motor branch (RMB) of the median nerve is not commonly reported. This report deals with a case of fascial band compression of the RMB of the median nerve with sparing of the sensory portion of the nerve in a single patient. The episode was precipitated by the subject was clearing fallen trees after an ice storm. Symptoms occurred only in the left, nondominant hand of the patient, a 43-year-old invasive cardiologist. He presented within weeks of symptom onset, but marked clinical and electrodiagnostic abnormalities of the branch were already present. Timely decompression after evaluation led to a successful clinical outcome, with restoration of full strength on manual muscle testing by 6 months postoperatively and marked electrodiagnostic improvements as well by 11 months after operation. Final clinical examination 16 months after operation showed thenar muscle bulk and strength well maintained.

Anatomy of Neurovascular Structures Around the Carpal Tunnel During Dynamic Wrist Motion for Endoscopic Carpal Tunnel Release

The purpose of this study is to investigate the anatomic relationship between neurovascular structures and the transverse carpal ligament (TCL) so as to avoid complications during an endoscopic carpal tunnel release procedure. Fresh cadaver hands from seven men and 12 women (age range, 48-74 yr) were used. The neurovascular structures just over and under the TCL were meticulously dissected under loupe magnification. Several anatomic landmarks were calculated (average length of the TCL; average distance between the TCL distal margin and the neurovascular structures; and average lengths of the superficial palmar arch, ramus communicantes, recurrent motor branch, and palmar cutaneous branch of the median nerve). The ulnar neurovascular structure was studied with the wrist positioned in neutral, ulnar flexion, and radial flexion. The anatomic relationships between the TCL and vascular and neural structures were measured. The ulnar neurovascular structures usually passed just over ulnar to the superior portion of the hook of the hamate. However, in 11 hands, a looped ulnar artery coursed 1 to 4 mm radial to the hook of the hamate and continued to the superficial palmar arch. The looped ulnar artery migrates on the ulnar side of Guyon's canal (-2-2 mm radial to the hook of the hamate) with the wrist in radial flexion (of the wrist). During ulnar flexion of the wrist, the ulnar artery shifts more radially beyond the hook of the hamate (2-7 mm). It is appropriate to transect the ligament over 4 mm apart from the lateral margin of the hook of the hamate without placing the edge of the scalpel toward the ulnar side. We would also recommend not transecting the TCL in the ulnar flexed wrist position to protect the ulnar neurovascular structure. The proximal portal could be made just ulnar to the palmaris longus tendon to spare the neurovascular structures in the proximal portion of the TCL.

Pitfalls of endoscopic carpal tunnel release

The objective of this study was to evaluate the causes of failed endoscopic carpal tunnel release (CTR) in order to detect potentially hazardous operative steps. The intraoperative findings of 10 microsurgically revised cases were retrospectively analyzed. From January 1999 to October 2001, ten patients underwent open revision surgery after being referred because of failed endoscopic carpal tunnel release (CTR). The median nerve had been injured in five cases, necessitating autologous sural nerve grafting in four. Two other patients underwent extensive (external and internal) neurolysis. The lesions were located twice in the main nerve trunk, three times in the recurrent motor branch, three times in a digital nerve, and once in the sensory palmar branch. The transverse carpal ligament (TCL) had not been sectioned in four cases and was incomplete in two. In another two cases, previously sectioned TCLs were closed again by firm fibrous tissue. In three cases, postoperative hematomas after the initial release were described and possibly contributed to symptoms. Endoscopic CTR in the hand of the inexperienced bears major risks for iatrogenic neurovascular injury.

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.

Distal excitability properties of median motor axons

Excitability properties were recorded from 14 volunteers following stimulation of the recurrent motor branch of the median nerve in the palm. Distal stimulation resulted in significantly lower strength-duration time constant and lower threshold during prolonged hyperpolarization than did wrist stimulation in the same subjects. These differences may be geometric in origin or alternatively may arise from functional changes distally, particularly reduced expression of persistent Na(+) conductances and more hyperpolarization-activated current. Excitability studies using palm stimulation provide information closer to the neuromuscular junction, where membrane properties are preferentially affected in a variety of clinical conditions.

Endoscopic carpal tunnel release and nerve conduction studies.

We investigated the outcome of endoscopic carpal tunnel release (ECTR) for patients with carpal tunnel syndrome (CTS) in comparison with the results of preoperative nerve conduction studies. The compound muscle action potential (CMAP) of the abductor pollicis brevis muscle (APB) and the second lumbrical muscle (L2) was recorded following median nerve stimulation at the wrist. A total of 38 hands in 35 patients were classified into four categories. Hands with a similarly prolonged distal motor latency for the APB and L2 were classified as type I (n=25), while those with a more prolonged distal motor latency for the APB than for the L2 (>0.7 ms) were classified as type 2 (n=10). Hands with a CMAP for the APB, but not L2, were classified as type 3 (n=1), and hands with no CMAP for either the APB or L2 were classified as type 4 (n=2). After ECTR, all of the type 1 and 2 hands were improved. Patients with type 3 and type 4 hands did not show satisfactory improvement, which may have been due to anatomical variation of the recurrent motor branch of the median nerve.

電気生理学的にみた鏡視下手根管開放術の適応

We investigated the indication of endoscopic carpal tunnel release (ECTR) for carpal tunnel syndrome (CTS) based on the results of a nerve conduction study (NCS). 38 hands of 35 patients with CTS were divided into 4 types preoperatively based on the results of the NCS. The compounds muscle action potentials (CMAPs) were recorded at the abductor pollicis brevis (APB) and the second lumbrical muscle (L2) following median nerve stimulation at the wrist. CTS with similar prolonged distal motor latency of the APB and L2 was included in type 1 (25 hands). CTS with prolonged distal motor latency of the APB longer than that of L2 (>0.7ms) was included in type 2 (10 hands). CTS with the CMAPs at the APB alone recordable was included in type 3 (3 hands). CTS in which the CMAPs at the APB and L2 were not elicited was included in type 4 (2 hands). After ECTR, all the CTS of type 1 and 2 improved well and the latency difference between APB and L2 was reduced for type 2. In 1 type 3 hand, the CMAPs at the APB were not elicited, although the CMAPs at L2 improved. In 1 of 2 type 4 hands, CMAPs at L2 alone were elicited.In conclusion, the ECTR was indicated for CTS of type 1 and 2 abnormality, but a few patients with type 3 and 4 abnormality had poor results with the ECTR probably due to the anatomical variation of the recurrent motor branch to the APB.

Riche-Cannieu connection in median nerve injuries

The Riche-Cannieu connection between the deep branch of the ulnar nerve and the recurrent motor branch of the median nerve was first noted in hand dissections almost 100 years ago. It was then considered rare and unimportant. Electrophysiologists have recently shown that this connection occurs in a large proportion of normal volunteers and accounts for a variable proportion of motor response in the thenar musculature. This report describes two cases of median nerve injuries with intact thenar function and postulates that this anomalous clinical presentation is due to the Riche-Cannieu connection. The unusual clinical situations emphasize the need for careful evaluation of nerve injuries.

Influence of peripheral afferents on cortical and spinal motoneuron excitability

The objective of this study was to establish to what extent muscle, cutaneous, and joint afferents alter the excitability of spinal and cortical motor neurons. This question was examined by studying the impact of electrical stimulation of the second and third digits, the median nerve at the wrist, and the recurrent thenar motor branch on the F/H and magneto-electrical cortical motor responses (MEPs) of the thenar muscles. The firing frequencies of single F/H motor unit action potentials were unaltered by the foregoing conditioning peripheral stimuli. MEPs conditioned by motor threshold stimulation of the median nerve at the wrist or the recurrent motor branch were significantly increased in size at conditioning to test intervals of 50 to 80 milliseconds. No significant change in MEP size resulted from conditioning stimulation of the digital nerves. We conclude that muscle afferents were primarily responsible for the increase in MEP size. Conditioning stimuli may allow examiners to assess central motor conduction where it would otherwise be impossible.