Thenar Branch Research Articles

Innervation of thumb carpometacarpal joint: implications for diagnostic block and denervation procedures

IntroductionOsteoarthritis (OA) of the thumb carpometacarpal (CMC) joint is a common disorder that negatively impacts hand function. Denervation of the thumb CMC joint has emerged as a viable treatment option....

Base of the Third Metacarpal as a Palpable and Reliable Landmark for Identifying the Median Nerve’s Thenar Branch

The objective of this study was to investigate whether the base of the third metacarpal can predict the location of the thenar branch (TB) of the median nerve and the accuracy of palpating the base of the third metacarpal. In 15 patients with ulnar nerve lesions around the elbow, we transferred the opponens motor branch to repair the deep terminal division of the ulnar nerve (DTDUN). Before surgery, we located the TB by palpating the base of the third metacarpal volarly. During surgery, we placed three needles at the following places: one at the entrance of the TB into the abductor pollicis brevis, another at the point where the TB contacted the thenar muscles, and third at the DTDUN's trajectory over the third metacarpal. We obtained fluoroscopic images and measured distances between the needles and structures with image software. We also examined the relationship between the TB, DTDUN, and the volar tubercle of the base of the third metacarpal in cadaver hands. Finally, we invited 22 surgeons to palpate the base of the third metacarpal on volunteer hands and verified their accuracy using fluoroscopy. During surgery, after dissection and palpation of the TB, under fluoroscopy, we confirmed that the palpable bone prominence was the base of the third metacarpal. In cadaver dissections, we observed the TB crossing the volar tubercle of the base of the third metacarpal superficially from proximal to distal and from ulnar to radial. The DTDUN was, on average, 14 mm distal to the base of the third metacarpal distal limit. In total, 19 of the 22 surgeons correctly identified the base of the third metacarpal and consequently the trajectory of the TB. The palpable base of the third metacarpal can be used to determine the trajectory of both the TB and DTDUN. Diagnostic II.

Distal Nerve Exploration in the Palm Avoids Nerve Transfer in a Posttraumatic Ulnar Nerve Injury with a Claw Hand

AbstractPosttraumatic low ulnar nerve injuries develop claw hand and poor hand function. Transferring the opponens pollicis branch of the thenar branch at the palm to the terminal division of the deep branch of the ulnar nerve is an effective distal nerve transfer to restore pinch in low ulnar nerve injuries. The author describes the surgical technique for a 4-month-old low ulnar nerve injury in a 25-year-old man with inconclusive electrodiagnostic findings and no clinical findings of distal nerve recovery. The intraoperative electrical stimulation of the nerve in the palm is a simple method to ensure the reinnervation of the ulnar nerve in a claw hand and muscle wasting. Therefore, all postcut injuries with a low ulnar nerve palsy with claw hands may not need a distal nerve transfer. However, performing distal nerve exploration in the palm is vital in cases of doubtful nerve recovery in a low ulnar nerve palsy with a claw hand.

Combined hypothenar fat pad flap and delayed neurorrhaphy for transected thenar branch during carpal tunnel release

Combined hypothenar fat pad flap and delayed neurorrhaphy for transected thenar branch during carpal tunnel release

Abductor Digiti Minimi and Anterior Interosseous to Ulnar Motor Nerve Transfer: The Super Turbocharge End-to-Side Transfer.

Anterior interosseous nerve to ulnar motor nerve supercharged end-to-side (SETS) nerve transfer to restore intrinsic function is a recently adopted nerve transfer in severe ulnar neuropathy. Its success is predicated on the critical threshold number of axons innervating the intrinsic muscles. Given the relative expendability of the abductor digiti minimi (ADM) muscle and the critical function of the other intrinsic muscles, the authors modified their SETS transfer to redirect axons from the ADM to turbocharge the ulnar motor nerve to innervate the more critical intrinsic muscles. They refer to this procedure as a super turbocharged end-to-side (STETS) procedure. The ADM has been used previously as a muscle/tendon transfer for thumb opposition and more recently as a nerve transfer to reinnervate the thenar branch of the median nerve. Although current methods of assessment of reinnervation are likely unable to differentiate between contributions from the anterior interosseous nerve SETS versus ADM STETS transfer, this technique follows the fundamentals of modern nerve surgery, where directing the maximum number of nerve fibers in a timely fashion to the most critical target is paramount for the best functional recovery. The authors suggest that the STETS technique may optimize outcomes in ulnar neuropathy without additional patient morbidity.

Surgically Treated Neuroma in Upper Extremity: Patient Characteristics and Factors Influencing Outcome of Surgery.

Background:Neuroma formation occurs after inappropriately or untreated nerve injuries. Patients surgically treated for neuroma were characterized and factors influencing outcome evaluated.Methods:In a retrospective observational study, data from medical records of patients surgically treated for neuroma in two Swedish regions were analyzed.Results:In 115 included patients (median age at surgery 45 years [IQR 29–55]), 55% (62/115) were men and 49% (56/115) were manual laborers. Most affected nerves were in hand or lower forearm (76/115, 66%). Smoking habits, affected nerves, and cause/mechanism(s) of injury differentiated the sexes. More motor nerve injuries were observed among women and more mixed nerve injuries among men. Iatrogenic injuries, such as injury to superficial sensory radial nerve or thenar branch of median nerve, more frequently affected women (27/52, 52%). Pain, the dominant preoperative symptom, improved after surgery. Overall, surgery cured/improved 79 of 115 (69%) patients. Patients treated with repair or reconstruction (n = 62) were younger than patients given neuroma transpositions (n = 43) and sensory nerve injuries were more often treated by transposition. No difference in outcome was observed concerning patient characteristics or surgical methods. Most patients had one surgery (102/115, 89%). No specific risk factors for a re-operation could be identified, but need for re-operation(s) was associated with poor outcome, even after repeated surgery.Conclusions:Patients with a neuroma benefit from surgery with significantly reduced pain, but symptoms may remain. Surgical method does not affect outcome. Preventing neuroma formation is crucial, presently highlighted in a high frequency of iatrogenic injuries, especially among women.

“Million dollar nerve” magnetic resonance neurography: first normal and pathological findings

To evaluate prospectively the feasibility of magnetic resonance neurography (MRN) in identifying the anatomical characteristics of thenar muscular branch (TMB) of the median nerve, also known as the "million dollar nerve," in patients and controls. Thirteen patients affected by carpal tunnel syndrome (CTS) and four healthy controls had their hands scanned on a 3-T MR imaging scanner for TMB visualization. Median nerve anatomical variations were classified into four groups according to Poisel's classification system modified by Lanz. TMB signal intensity and diameter were assessed for the diagnosis of neuropathy. TMB was successfully identified in all patients and subjects by using MRN. The most suitable pulse sequences to identify and measure nerve diameter were 3D DW-PSIF and T2-FS-TSE. The axial oblique and sagittal oblique planes are complementary in demonstrating its entire course. TMB had mostly an extraligamentous course with radial side origin (93.8%, each). All patients experienced increased T2 signal intensity (p < 0.001) and thickened nerves. Mean TMB diameters were 1.27 ± 0.21 mm (range, 1.02-1.74 mm) and 0.87 ± 0.16 mm (0.73-1.08 mm) (p = 0.008) in the patient and control groups, respectively. MRN is a reliable imaging technique for identification and anatomical characterization of TMB in patients affected by CTS. This innovative imaging workup may therefore be included in the preoperative evaluation of patients scheduled for carpal tunnel release, especially in CTS with TMB involvement or even in isolated TMB neuropathy. • Magnetic resonance neurography allows precise visualization of the thenar muscular branch of the median nerve. • Thenar muscular branch anatomical variations can be correctly identified. • Preoperative scanning can contribute to reducing the risk of iatrogenic injuries during carpal tunnel release, especially in carpal tunnel syndrome with thenar muscular branch involvement or even in isolated thenar muscular branch neuropathy.

Single incision thenar muscle reconstruction using the free functional pronator quadratus flap

BackgroundInjuries to the thenar muscle mass or the thenar branch of the median nerve and resulting loss of thumb opposition lead to a massive impairment of hand function. For decades, reconstructive approaches were based on tendon transfers. To broaden the reconstructive repertoire, we present the free functional pronator quadratus flap as a viable alternative for functional reconstruction and provide a specification for its indication. We demonstrate our surgical technique to a single incision reconstruction using the free functional pronator quadratus flap. Based on a series of three patients, which were analyzed for hand function using Kapandji’s score and the angle of Bourrel, grip strength and nerve conduction velocity in a two year follow up, we present an indication algorithm.ResultsAfter successful reinnervation of all flaps, we found an improvement of Kapandji’s score from 4.3 ± 0.94 preoperatively, to 8.7 ± 0.47 after two years. Accordingly, the angle of Bourrel decreased from 75.75 ± 3.45 degrees to 36.96 ± 3.68 degree. Grip strength also improved from 14 ± 2.2 kg to 26.2 ± 1.2 kg. No impairment of wrist pronation was observed.ConclusionWe found excellent functional recovery of thumb opposition and strength, showing similar or even superior results compared to results from tendon transfers. With the benefit of a single incision surgery and therefore minimal donor site morbidity, this free functional muscle transfer is a viable alternative to classic tendon transfers.

Innervation of digital joints: an anatomical overview.

IntroductionThe innervation of the digital joints as well as the anatomical relationships of the articular branches is present in this anatomical work to determine the technical feasibility of a selective and efficient denervation of the digital joints.Materials and methodsA study of 40 distal interphalangeal (DIP), 40 proximal interphalangeal (PIP), 50 metacarpophalangeal (MCP), 10 interphalangeal (IP) of the thumb, and 10 trapezo-metacarpophalangeal (TMC) joints was performed on ten hands. Under magnification and a proper surgical approach, we collected the course, the source origin, the number of articular nerve branches, and their caliber.ResultsIn total, 118 nerve branches arising from the proper palmar digital nerves were found on 10 DIP of each dissected long finger (n = 40). A total of 226 nerve branches were found on 10 PIPs of each long finger (n = 40), of which 204 branches (90.3%) had a palmar origin. Dorsal innervation was found for the ring and little finger, originating from the dorso-ulnar digital nerve. 212 branches were found on 10 MCP of long fingers (n = 40), including 87 branches of palmar origin (41.1%), 107 branches of dorsal origin (50.4%), and 18 branches of the motor branch of the ulnar nerve (8.5%). 42 articular branches directed to the TMC joint (n = 10) were found. 13 branches (31%) originated from the anterior sensory branch of the radial nerve, 13 branches (31%) originated from the lateral cutaneous nerve of the forearm, 5 branches (12%) originated from the palmar cutaneous branch of the median nerve, and 11 (26%) branches originated from the thenar branch of the median nerve. The involvement of the sensory anterior branch of the radial nerve was always present for the innervation of each TMC.Discussion and conclusionOur research shows that finger joints receive their primary innervation from small branches of the digital nerves with the exception of the MCP joint and the TMC joint. To obtain an efficient and a selective digital denervation for articular pain relief, it is necessary to plan the best surgical approach and it is crucial to recognize the articular nervous branch localization and source.

Anatomical variation of the median nerve and its thenar branch: Clinical and surgical application in the treatment of carpal tunnel syndrome

Anatomical variation of the median nerve and its thenar branch: Clinical and surgical application in the treatment of carpal tunnel syndrome

Anatomical variation of the median nerve and its thenar branch: Clinical and surgical application in the treatment of carpal tunnel syndrome

Carpal tunnel syndrome is the most common root canal pathology. The surgical treatment corresponds to a release of the median nerve by incision of the anterior annular ligament of the carpus by open surgical treatment or endoscopy. Knowledge of the normal anatomy and anatomical variations of the median nerve at the wrist is fundamental to avoiding complications in median nerve release in the treatment of carpal tunnel syndrome. Through this work we will show the interest of knowledge of the anatomy of the median nerve as well as its anatomical variations in order to derive the main clinical applications and to avoid the risks associated with open or endoscopic surgery in the treatment of carpal tunnel syndrome.

A novel nerve transfer: The first palmar interosseous motor branch of the ulnar nerve to the recurrent motor branch of the median nerve

IntroductionThe recovery of recurrent motor branch of the median nerve might be delayed in high level median nerve injuries due to the long reinnervation distance. The aim of this study is to define a novel nerve transfer to restore the opposition and pinch. MethodsTwo fresh frozen hand cadavers were used for the study. The motor branch of the first palmar interosseous muscle of the ulnar nerve was identified and dissected. Thenar branch of the median nerve was dissected from its insertion site. The motor branch of the first palmar interosseous muscle of the ulnar nerve was transferred to the thenar motor branch of the median nerve. Axon counts were examined histopathologically. Clinically this nerve transfer was performed for two female patients with a high-level median nerve injury. Mehta opposition scores were 21 and 20, respectively and the results were satisfactory six months after the surgery. DiscussionAlthough exploration and repair are recommended as the first treatment for median nerve injuries, the waiting time until the motor branch is reinnervated is critical in high level lesions. Nerve transfers become very important for fast recovery. ConclusionsThis new nerve transfer proposal may be an important step in nerve transfer surgery.

Nerve transfer of the anterior interosseous nerve to the thenar branch of the median nerve – an anatomical and histological analysis

Nerve transfer has become a vital method in the reconstruction of hand function. Reconstructing the motor function to the thenar musculature has proven to be difficult and is rarely satisfactory following direct anatomic repair. The aim of this investigation was to describe the anatomic results obtained by transferring the anterior interosseous nerve to the thenar branch of the median nerve and analyze the histomorphometric results. Nerve transfers were performed in 15 fresh anatomic specimens. Nerve samples were excised from 13 fresh specimens and histologically investigated. The nerve diameter, fascicle number, and cross-sectional area of the individual fascicles were measured. The results of this investigation revealed that the anterior interosseous nerve and the thenar branch of the median nerve could be identified at their expected locations and a tension-free coaptation could be achieved. The anterior interosseous branch had a mean number of 606 ± 254 axons vs. 2160 ± 1326 in the thenar branch (p < 0.001). The anterior interosseous branch had a mean density of axons per fascicle mm2 of 2398 ± 829 vs. 3012 ± 740 in the thenar branch (p = 0.390). The ratio of axons between the thenar branch of the median nerve and the anterior interosseous nerve yielded a mean of 1:4.16. Nerve transfer of the anterior interosseous nerve to the thenar branch of the median nerve should be considered as a viable option but remains a subject of investigation owing to its critical axon ratio. Furthermore, larger clinical studies will be required to validate or neglect this nerve transfer.

Transferring the Motor Branch of the Opponens Pollicis to the Terminal Division of the Deep Branch of the Ulnar Nerve for Pinch Reconstruction.

With ulnar nerve injuries, paralysis of the first dorsal interosseous (FDI) and the adductor pollicis (ADP) muscles weakens pinch. The likelihood that these muscles will be reinnervated following ulnar nerve repair around the elbow is very low. To overcome this obstacle, we propose a more distal repair: transferring the opponens pollicis motor branch (OPB) to the terminal division of the deep branch of the ulnar nerve (TDDBUN). We dissected 10 embalmed hands to study the anatomy of the thenar branches of the median nerve and TDDBUN. We also operated on 3 patients with recent ulnar nerve injuries around the elbow, suturing the ulnar nerve and transferring the OPB to the TDDBUN. Before and after surgery, we measured grasp, key pinch, and pinch-to-zoom strength using dynamometers. Pinch-to-zoom gesture consists of moving the index finger and thumb pulp toward each other for zooming out of an image on screen. Patients were followed for at least 15 months. The thenar branch of the median nerve innervated the abductor pollicis brevis and opponens pollicis in all specimens, but only half the superficial head of the flexor pollicis brevis. The TDDBUN gave off a single motor branch to the transverse head of the ADP, 1 or 2 branches to the oblique head, and a final branch to the FDI. The ratio of myelinated fibers between the OPB and the TDDBUN was 3:5. Relative to the normal side, pinch-to-zoom strength was mostly affected by the ulnar nerve lesion, with strength decreased by 80% to 90%. After surgery, we observed reinnervation of the FDI and an 80% to 90% improvement in pinch-to-zoom strength. Transferring the OPB to the TDDBUN provided reinnervation of the FDI andADP, thereby contributing to pinch strength improvement. Therapeutic V.

Thumb Opposition Recovery Following Surgery for Severe Carpal Tunnel Syndrome: A Clinical, Radiological, and Electrophysiological Pilot Study.

To objectively assess recovery of thumb opposition in patients with carpal tunnel syndrome (CTS) after open carpal tunnel release and to evaluate electrophysiological and magnetic resonance (MR) neurography findings as predictors of thumb opposition recovery. A total of 22 patients with severe CTS and thenar atrophy were included in this study. A detailed clinical, electrophysiological, and MR neurography evaluation was done both before and after surgery at 6 months to assess thumb opposition recovery. The median duration of symptoms was 12 months (interquartile range, 12-20 months). The compound muscle action potential of the abductor pollisis brevis (CMAP-APB) alsoshowed statistically significant improvement of 0.5+ 0.2 mV after surgery. Tip-tip pulp pinch strength increased from 1.2 ± 0.4 to 2.0 ± 0.4 kg at 6-month follow-up, lateral pulp pinch strength increased from 1.9 ± 0.6 to 2.8 ± 0.9 kg at 6-month follow-up, and 3-point pulp pinch also improved from 1.9 ± 0.5 to 2.8 ± 0.9 at final follow-up. On MR neurogram, the proportion of patients with abnormal median nerve morphology decreased from 81.8% to 68.2%, abnormal thenar branch morphology decreased from 63.6% to 36.4% and denervation edema deceased from 59.1% to 13.6%. Patients suffering from severe CTS with thenar atrophy and detectable CMAP-APB showed promising improvement following open carpal tunnel release. Prognostic IV.

Anastomose de Riché‐Cannieu: estrutura, função e significância clínica

ObjectiveDefine the anatomy pattern and the incidence of Riché‐Cannieu anastomosis (RCA), i.e., median and ulnar communication in palmar aspect of the hand. MethodsA total of 80 anatomical dissections were performed on 60 limbs of 30 cadavers from 1979 to 1982, and on 20 limbs from 2012 to 2015. All procedures were realized at the Department of Anatomy of this institution. The incidence of Riché‐Cannieu anastomosis and innervation of the thenar muscles were studied. ResultsThe Riché‐Cannieu anastomosis was identified in all dissected hands (100%). Extramuscular Riché‐Cannieu anastomosis was recorded in 57 hands and intramuscular in 19 hands. The association of extra‐ and intramuscular Riché‐Cannieu anastomosis occurred in four. The ulnar component always originated from the deep branch. The anastomotic branch arising from the median nerve originated from the motor thenar branch (recurrent branch) of the median nerve in the majority of the observations. The median‐ulnar double innervation to the deep head of the flexor pollicis brevis alone was identified in 29 of 80 hands. In 12 limbs, the deep head of the flexor pollicis brevis was absent. The double innervation of the superficial head of the flexor pollicis brevis was found alone in 13 hands. The double innervation of the superficial and deep heads of the flexor pollicis brevis in the same hand occurred in 14 hands. The oblique head of the adductor pollicis received double innervation in 12 hands. The deep head of the flexor pollicis brevis and the oblique head of adductor pollicis in the same hand were doubly innervated in nine hands. The transverse head of adductor pollicis received double innervation in two hands. The double innervation of the deep head of the flexor pollicis brevis and the transverse head of the adductor pollicis was found in one limb. ConclusionAccording to this study, the Riché‐Cannieu anastomosis should be labeled as a normal anatomical neural connection and not as an anatomical variation. Knowledge of this anastomosis is essential because the presence of such neural communication can cause confusing clinical, surgical, and electromyographic findings in cases of median or ulnar damage or entrapment.

Transfer of the Motor Branch of the Abductor Digiti Quinti for Thenar Muscle Reinnervation in High Median Nerve Injuries.

In high median nerve repairs, thenar muscle reinnervation is impossible because of the long distances over which axons must regenerate. To overcome this obstacle, we propose transferring the abductor digiti quinti motor branch (ADQMB) to the thenar branch of the median nerve (TBMN). We used 10 embalmed hands for anatomical and histological studies. Thereafter, 5 patients with a high median nerve injury underwent surgical reconstruction within 8 months of their accident and were followed for at least 10 months after surgery (mean, 13.2 months). We transferred the ADQMB to the TBMN. The median nerve was grafted in 4 patients and the motor branch of the extensor carpi radialis brevis was transferred to the anterior interosseous nerve in 3. Patients had pre- and postoperative evaluations of thumb range of motion and strength. In cadaveric hands, the ADQMB was the first branch of the ulnar nerve to arise near the pisiform bone. The TBMN arose from the anterior surface of the median nerve, underneath the flexor retinaculum. Retrograde dissection of the TBMN allowed tension-free coaptation with the ADQMB. Both branches contained approximately 650 myelinated fibers. After surgery, all our patients improved thumb pronation, thenar eminence bulk, and abductor pollicis brevis British Medical Research Council score. They recovered approximately 75% of their normal-side grasp and pinch strength. No patient lost little finger abduction. Transfer of the ADQMB to the TBMN reinnervated the thenar muscles, whichimproved thumb range of motion and strength. Therapeutic V.

A study on variations of branching patterns of median nerve in the carpal tunnel

Abstract Background &amp; aims: The carpal tunnel, located on the palmar surface of the wrist, is a common site of median nerve compression. The median nerve, on passing through the carpal tunnel, divides into lateral and medial branches. The lateral branch then gives off proper palmar digital branches to the thumb and the radial aspect of the index finger, and a recurrent muscular branch to the thenar muscles. The recurrent muscular branch shows different types of variations of the median nerve. Also, there are other variations of the median nerve in the carpal tunnel. These variations greatly influence the symptoms, as well as the treatment of the carpal tunnel syndrome. So, the present work is carried out to study the variations of branching patterns of median nerve in the carpal tunnel. Materials and methods: 40 wrists [20 right and 20 left] from 20 formaldehyde fixed human perinatal fetuses of 34 - 38 weeks of gestation were dissected in the Department of Anatomy, Gauhati Medical College and Hospital, Guwahati. Due ethical clearance was obtained from the Institutional Ethical Committee, Gauhati Medical College and Hospital, Guwahati. Results: In the present study, 24 [66.7%] hands [11 right and 13 left] showed extraligamentous and 12 [33.3%] hands [8 right and 4 left] showed transligamentous variety of thenar branch of median nerve. Also, 4 [10%] hands showed accessory thenar branch of median nerve, all of which took origin within the flexor retinaculum. The comparisons of numbers of variations of thenar branch of median nerve between right and left hands were found to be statistically non significant [P &gt; 0.05]. Conclusion: A detailed knowledge of the median nerve variations in the carpal tunnel is required for successful diagnosis and treatment of the carpal tunnel syndrome and its complications.

Erratum to: an unusual pre-ligamentous thenar motor branch of the median nerve

Erratum to: an unusual pre-ligamentous thenar motor branch of the median nerve

Ultrasound imaging of the thenar motor branch of the median nerve: a cadaveric study

IntroductionAnatomic variations of the median nerve (MN) increase the risk of iatrogenic injury during carpal tunnel release surgery. We investigated whether high-frequency ultrasonography could identify anatomic variations of the MN and its thenar motor branch (MBMN) in the carpal tunnel.MethodsFor each volar wrist of healthy non-embalmed cadavers, the type of MN variant (Lanz classification), course and orientation of the MBMN, and presence of hypertrophic muscles were scored by 18-MHz ultrasound and then by dissection.ResultMBMN was identified by ultrasound in all 30 wrists (15 subjects). By dissection, type 1, 2 and 3 variants were found in 84%, 3%, and 13% of wrists, respectively. Ultrasound had good agreement with dissection in identifying the variant type (kappa =0.9). With both techniques, extra-, sub-, and transligamentous courses were recorded in 65%, 31%, and 4% of cases, respectively. With both techniques, the bifid nerve, hypertrophic muscles, and bilateral symmetry for variant type were identified in 13.3%, 13.3%, and 86.7% of wrists, respectively. Agreement between ultrasound and dissection was excellent for the MBMN course and orientation (kappa =1).ConclusionUltrasound can be used reliably to identify anatomic variations of the MN and MBMN. It could be a useful tool before carpal tunnel release surgery.Key Points• Ultrasound can identify variations of the motor branch of the median nerve.• Ultrasound mapping should be used prior to carpal tunnel release surgery.• All sub-, extra-, and transligamentous courses were accurately identified.• Type 3 variants (bifid nerve), hypertrophic muscles, and bilateral symmetry were accurately identified.