How to prevent injury to the palmar cutaneous branch of median nerve and ulnar nerve in a palmar incision in carpal tunnel release, a cadaveric study

Objective

To identify palmar cutaneous branches of median nerve and ulnar nerve (PCBMN and PCBUN) and try to find a safe path at wrist and forearm in the decompression procedure of carpal tunnel syndrome.

Materials and methods

Ten formalin-fixed and five fresh-frozen cadaveric forearms were included in the study. The cross point of longitude of middle finger and distal wrist crease was defined as 0 point. Distal wrist crease (DWC) and 0 point were chosen as references for measurements. Several points on the pathway of PCBMN and PCBUN were measured.

Results

The average distance between the origin of the PCBMN and PCBUN to the DWC was 4.95?±?0.88 cm, 10.12?±?1.50 cm, separately. The average distance between DWC and the point where PCBMN and PCBUN separated from their trunk was found to be 2.09?±?0.31 cm, 2.90?±?0.50 cm, separately. The distances between PCBMN, PCBUN and 0 point at DWC level was found to be 0.61?±?0.12 cm, 0.47?±?0.31 cm, separately. The diameters of two cutaneous branches were 0.10?±?0.02 cm, 0.11?±?0.04 cm, separately.

Conclusion

The general longitudinal palmar incision could avoid injuries to recurrent branch of median nerve and distal branches of palmar cutaneous nerve can be avoided macroscopically. The area about 5 mm ulnar and 6 mm radial to 0 point at wrist level was a relatively safe area.     

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。     

Innervation of the wrist joint and surgical perspectives of denervation

PURPOSE: Because our experience with the techniques used in denervation surgery of the wrist joint often has proven insufficient in treating chronic pain we conducted an anatomic study to clarify the exact contributions of the nerves supplying the wrist joint. Our goal was to reveal all periosteal and capsular nerve connections and if necessary adjust our technique used in denervation surgery. METHODS: Innervation of the wrist joint was investigated by microdissection and histologic examination of 18 human wrists. An acetylcholinesterase method was used to identify the nerves, both in whole-mount preparations and in sections. RESULTS: We found that the main innervation to the wrist capsule and periosteal nerve network came from the anterior interosseous nerve, lateral antebrachial cutaneous nerve, and posterior interosseous nerve. The palmar cutaneous branch of the median nerve, the deep branch of the ulnar nerve, the superficial branch of the radial nerve, and the dorsal branch of the ulnar nerve also were found to have connections with the capsule. The periosteal nerve branches did not appear to play a major role in the innervation of the capsule and ligaments; here the specific articular nerve branches proved more important. The posterior and medial antebrachial cutaneous nerves did not connect to the wrist capsule or periosteum but rather terminated in the extensor and flexor retinaculum. CONCLUSIONS: Based on our findings we propose to denervate the wrist by making 2 incisions. With one palmar and one dorsal incision it should be possible to disconnect the periosteum from the capsule and interrupt the majority of the capsular nerve branches.     

阻断部分臂丛神经下干分支对健侧颈7移位下干后神经再生的影响

目的 以大鼠健侧颈7直接修复臂丛神经下干为模型,探讨阻断下干分支前后,尺神经和正中神经神经纤维数量和质量的变化.方法 雌性SD大鼠40只,随机分成4组.A组:健侧颈7直接修复下干,并从下干发出处阻断下干后股、胸前内侧神经、前臂内侧皮神经;B组:健侧颈7直接修复下干,并从下干发出处以远1 cm处阻断下干后股、胸前内侧神经、前臂内侧皮神经;C组:健侧颈7直接修复下干,并从下干发出处切断后股;D组:对照组.术后比较尺神经、正中神经、胸前内侧神经和前臂内侧皮神经的神经纤维数量、神经纤维密度(p)、神经纤维数占下干神经纤维总数百分比、神经纤维直径、有髓神经纤维面积与相应分支神经总面积比(N Ratio).结果 尺神经和正中神经中,神经纤维数量、神经纤维密度、正中神经与尺神经分别占下干神经纤维百分比、神经纤维直径、不同直径神经纤维百分比、N Ratio,A、B、C三组间差异均无统计学意义.前臂内侧皮神经和胸前内侧神经中,上述各检测指标B、C组间均无明显差异.结论 健侧颈7直接移位下干后,在根部及根部以远1 cm处阻断胸前内侧神经及前臂内侧皮神经后,对尺神经、正中神经、前臂内侧皮神经残端和胸前内侧神经残端中神经纤维的数量和质量无明显影响.

Abstract：

Objective To explore the changes of the nerve fibers from median and ulnar nerves after cutting the branches of lower trunk which was repaired by the contralateral C7.Methods Forty female SD rats were divided into A, B, C and D groups randomly.In group A,the contralateral C7 root was transferred to lower trunk directly, and the posterior division of lower trunk, medial anterior thoracic nerve and the medial antebrachial cutaneous nerve were severed at the beginning of them;In group B, the contralateral C7 root was trarsferred to lower trunk directly, and the posterior division of lower trunk, medial anterior thoracic nerve and the medial antebrachial cutaneous nerve were severed at the point which was 1 cm away from the beginning of above branches;In group C, the contralateral C7 root was transferred to lower trunk directly, and the posterior division of lower trunk was severed at the beginning of it;In group D, control group.After the operation, myelinated fiber count, nerve fiber density, the percentage of the number of nerve fiber from branch accounting for that from lower trunk, nerve fiber diameter,the percentage of nerve fibers with different diameters and N Ratio were carried out to evaluate the outcome of each group.Results Myelinated fiber count, nerve fiber density, the percentage of the number of nerve fiber from branch accounting for that from lower trunk, nerve fiber diameter,the percentage of nerve fibers with different diameters and N Ratio in ulnar and median nerve, there were no difference between group A, group B and group C ( P ＞ 0.05).Conclusion After the medial anterior thoracic nerve and medial antebrachial cutaneous nerve, repaired by the contralateral C7, were severed at the beginning and at the point which was 1 cm away from the beginning of above branches, the changes of the quantity and quality of the nerve fibers from median and ulnar nerves were not significant.     

手汗症患者胸交感神经干脑源性神经营养因子和神经调节因子-1基因表达与有髓神经纤维密度及横截面积的关系

目的 观察手汗症患者胸交感神经干脑源性神经营养因子(BDNF)和神经调节因子-1(NRG-1)基因表达及对有髓神经纤维密度和单个纤维横截面积的影响,探讨与手汗症发病机制的关系.方法 采用核固红-固绿髓鞘染色法显示有髓神经纤维,通过显微图像分析系统观察30例手汗症患者T3胸交感神经干有髓神经纤维密度和单个有髓神经纤维的横截面积,以及用逆转录-聚合酶链反应(RT-PCR)法检测BDNF和NRG-1基因表达强度,并与8例非手汗症患者进行对照研究.结果 手汗症患者T3胸交感神经干中有髓神经纤维密度和单个有髓神经纤维的横截面积较非手汗症患者明显增高(t=7.023,P<0.05;t=7.462,P<0.05);BDNF和NRG-1基因在手汗症患者T3胸交感神经干中mRNA水平的相对表达强度比值分别为1.17600±0.028 70、1.216 10±0.075 39,较非手汗症患者的比值1.037 50±0.053 79、1.042 70±0.043 57明显增高(t=9.940,P<0.05;t=6.195,P<0.05).结论 BDNF和NRG-1基因表达强度增高促使胸交感神经干的有髓神经纤维密度增高以及单个有髓神经纤维的横截面积增大,从而导致胸交感神经传导速度增快、兴奋性增高,可能为手汗症的发病基础之一.     

The cutaneous innervation of the dorsal hand: detailed anatomy with clinical implications

PURPOSE: Detailed knowledge of the anatomy of the cutaneous innervation to the dorsal surface of the hand is valuable information. Because surgical access to the wrist often is obtained via the dorsal skin it would be helpful particularly to delineate an area where surgical incisions would not injure underlying nerves. METHODS: Thirty cadaver forearms were dissected carefully to examine in detail the anatomy of the lateral antebrachial cutaneous nerve, the superficial branch of the radial nerve, and the dorsal branch of the ulnar nerve. Each hand then was evaluated for an area free of any major nerve branches over the dorsal wrist. RESULTS: Although the innervation to the dorsal hand varies certain patterns exist. The innervation pattern between the superficial branch of the radial nerve and the dorsal branch of the ulnar nerve is distributed evenly, dual innervation is frequent between the 2 nerves, and the lateral antebrachial cutaneous nerve is a common contributor to the innervation of the thumb. The superficial branch of the radial nerve and the dorsal branch of the ulnar nerve have identifiable branching patterns and have been classified according to a system developed for this study. CONCLUSIONS: Two classification systems based on detailed dorsal hand cutaneous innervation patterns can be used to specify the placement of a safe dorsal skin incision away from major nerve branches.     

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.     

游离尺动脉腕上皮支皮瓣修复手指创面

目的探讨尺动脉腕上皮支皮瓣修复手指创面的手术方法及效果。方法对11例手指皮肤软组织缺损合并肌腱或骨外露者,采用游离尺动脉腕上皮支皮瓣进行修复。其中8例面积为2．5cm×1．0cm-5．2cm×2．2cm的皮瓣．在腕上皮支下行支轴线上切取：3例面积为5．5cm×3．0cm×6．2cm×3．8cm的皮瓣,在腕上皮支下行支及上行支轴线上切取。皮瓣切取后,8例下行支皮瓣内腕上皮支主干均直接与受区指动脉吻合,3例合并有上行支的皮瓣均移植了前臂静脉与受区的指动脉吻合,皮瓣内的皮下静脉或伴行静脉分别与近端指掌侧或指背侧2-3根静脉吻合,将皮瓣内携带的1条尺神经手背支与指固有神经接合。结果术后11例皮瓣全部成活．并获得4～17个月随访。皮肤弹性、色泽、质地良好,外形满意。两点辨别觉9-12mm。结论游离尺动脉腕上皮支皮瓣供区隐蔽,血管穿支位置恒定,不损伤主干血管,供区损伤小,切取简单。修复手指缺损外观满意,可携带神经恢复皮瓣感觉,是修复手指创面的一种理想选择。     

Early structural effects of oestrogen on pudendal nerve regeneration in the rat

OBJECTIVE: To determine the early effects of oestrogen on the ultrastructure of the pudendal nerve and distal nerve fascicles near the external urethra sphincter (EUS) after a pudendal nerve crush injury. The pudendal nerve is one of the pelvic floor tissues injured during vaginal delivery, possibly contributing to the development of stress urinary incontinence (SUI) in women, the symptoms of which often do not appear until menopause, implicating hormonal factors. MATERIALS AND METHODS: Twenty-seven virgin female Sprague-Dawley rats were anaesthetized and underwent ovariectomy. Three days later, they had one of four procedures: bilateral pudendal nerve crush plus implant of a subcutaneous oestrogen-containing capsule (NC+E); nerve crush plus implant of a sham saline-containing capsule (NC+S); no nerve crush with an oestrogen capsule; or no nerve crush with a sham capsule. After 2 weeks the pudendal nerves and urethral tissues were prepared for light and electron microscopy. The number of axons, myelin figures and endoneurial nuclei in the pudendal nerve segment distal to the lesion were counted. Nerve fascicles near the EUS were also counted and categorized as normal or showing signs of degeneration and/or regeneration. The location of each nerve fascicle was specified as either ventral or dorsal. RESULTS: As there were no significant differences between the two control groups they were combined to form a single control group. In the distal pudendal nerve there were significantly fewer myelinated axons and large myelinated axons in the NC+E and NC+S groups than in the control group. There were three times as many large unmyelinated axons in the NC+E group than in either the NC+S or control groups (P < 0.05). There were only half as many nerve fascicles near the ventral side of the EUS in the NC+S group than in both the control and NC+E groups (P < 0.05). CONCLUSION: Oestrogen appears to affect large unmyelinated axons in both the injured pudendal nerve and at the denervated EUS target. After pudendal nerve crush, nerve fascicles with evidence of degeneration or regeneration near the EUS appear to be spared with oestrogen treatment, particularly in the ventral region. These observations may reflect the early stages of a neuroregenerative effect of oestrogen. Additional studies are needed to confirm these results at later periods and with functional methods.     

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.     

The nerve of Henlé

The nerve of Henlé, a branch of the ulnar nerve in the forearm, is thought to deliver sympathetic innervation to the ulnar artery. Forty cadaver forearms were dissected under magnification. Two distinct patterns of the nerve were found. In the typical pattern, 18 (45%) of 40 extremities, the nerve originates 16 cm proximal to the ulnar styloid, travels distally with the ulnar artery, and frequently, 13 (72%) of 18, branches to pierce the superficial fascia 6 cm proximal to the ulnar styloid and innervate the skin of the distal ulnar forearm. In the atypical pattern (12%), the nerve originates in the distal 8 cm of the forearm and travels briefly with the ulnar artery before branching to the skin. The palmar cutaneous branch of the ulnar nerve was absent in cadavers with the nerve of Henlé and may be a distal variant of that nerve.     

Entrapment neuropathy of the palmar cutaneous branch of the median nerve by the fascia of flexor digitorum superficialis

A case of thenar numbness, with concomitant carpal tunnel syndrome is presented. Physical findings and the result of injection of a local anesthetic into two different sites of tenderness suggested coexistence of entrapment and/or compression of the palmar cutaneous branch of the median nerve and the main trunk of the median nerve at the carpal tunnel. At operation, constriction of the palmar cutaneous branch of the median nerve by the fascia of seemingly normal flexor digitorum superficialis was observed beneath the site of maximum tenderness. After decompression of this nerve, combined with carpal tunnel release, the patient lost all pain and numbness; there was no recurrence at 5 months follow-up.     

Histologic structure of the ulnar nerve in the hand

Serial histologic sections of 20 ulnar nerves revealed broad individual variations in the number and diameter of the fascicles at all levels. The number of fascicles increased from the proximal portion to the distal portion, and interfascicular and perifascicular connective tissue occupied about 50% of the entire nerve section. These configurations explain the difficulties and setbacks encountered in the repair of injuries to the ulnar nerve. The counting of myelinated nerve fibers also revealed a great number of variations.     

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.     

改良体表定位前臂近段掌侧切口治疗桡骨近段骨折的安全性研究

目的用肱二头肌腱桡侧缘与桡侧屈腕肌肌腱的连线作为前臂近段掌侧切口术前体表定位线,探讨该体表定位方法的临床安全性。 方法回顾性分析自2012年1月至2016年4月期间,21例桡骨近侧1/3骨折患者的手术资料。术前体表定位切口的方法采用肱二头肌腱桡侧缘与桡侧屈腕肌肌腱连线,行切开复位钢板内固定术。其中男16例,女5例;年龄19~52岁,平均34岁。致伤原因：跌伤15例,交通伤3例,高处坠落伤2例,打架致伤1例。左侧12例,右侧9例。均为单纯桡骨干骨折、闭合性损伤、术前无神经损伤症状。受伤至手术时间为1~9 d,平均4 d。术后根据Grace和Eversmann标准对患者前臂旋转功能进行评价,并评价其前臂外侧皮神经支配区域的感觉情况。 结果本组患者术后获11~24个月（平均14个月）随访,所有骨折均获得骨性愈合,愈合时间均<6个月。根据末次随访时前臂功能评价的Grace和Eversmann标准：优15例、良4例、可2例,优良率为90.5%。无感染、内固定失败及神经或血管损伤等并发症发生,没有患者发生桡神经及前臂外侧皮神经损伤的症状。 结论通过改良体表定位前臂掌侧入路的方法,手术切开时能有效避免医源性前臂外侧皮神经损伤。术中以肱二头肌腱为参照,并确保在肱二头肌腱的桡侧进行操作。肱二头肌腱是安全可靠的定位标记。     

Radial nerve cross-finger flap differential nerve contribution in thumb reconstruction

Six patients with extensive palmar thumb pulp and soft tissue loss were treated with a staged transfer of radial nerve innervated flap tissues from the dorsum of the index finger. They were followed for a mean period of 3 years. This transfer of radial nerve innervated dorsal index finger tissues to the palmar surface of the thumb has been a successful method of innervation restoration. The ultimate sensibility of the reconstructed thumb seems to be a mixture of median and radial nerve sensibility. Sensory testing shows that after transfer, the ulnar side of the flap is more innervated from the radial nerve than the radial side. Our findings suggest that the presence of active sensory axons in the radial nerve innervated flap may play an inhibitory role in direct and/or functional neurotization of the transferred flap.     

Recovery of cutaneous pain sensitivity after end-to-side nerve repair in the rat.

OBJECT: The hypothesis that collaterally sprouting axons from an uninjured donor nerve may provide recovery of pain sensitivity in the skin after end-to-side nerve repair was investigated in rats. In addition, the effect of this technique on the donor nerve was examined. METHODS: The distal stump of the transected peroneal nerve was sutured end to side to the intact sural nerve. No epineurial window or perineurial slit was made in the sural nerve at the site of coaptation. Other nerves in the leg were transected and ligated. Eighteen weeks later, the sural nerve was transected at a site distal from the coaptation site. The residual pain sensitivity in the peroneal innervation field in the instep was documented using the skin pinch test in three of 11 animals. The area of sensitivity encompassed 19 to 40% of the maximum nociceptive innervation area of the normal peroneal nerve. The nerve pinch test revealed functional sensory axons in all communicating peroneal nerves, in which 277+/-119 myelinated axons (mean +/- standard deviation) were found by histological investigation. CONCLUSIONS: The authors conclude that at least partial recovery of sensory function due to collateral sprouting of axons after end-to-side nerve repair is possible in principle. However, the presence of functional sensory axons in the peroneal nerve stumps did not guarantee the recovery of skin sensitivity to pain in all animals. No functional or morphological evidence of an untoward effect of collateral sprouting into the end-to-side communicating nerve was detected in the axons of the donor nerve itself.     

Carbonic anhydrase histochemistry. A potential diagnostic method for peripheral nerve repair

Many large-diameter myelinated axons in spinal dorsal roots contain carbonic anhydrase activity, whereas few small-diameter ventral root axons stain for this enzyme. This differential localization of carbonic anhydrase in sensory and motor nerve fibers is indicative of the potential of carbonic anhydrase histochemistry to provide a convenient method for identifying predominantly motor or sensory fascicles in cut ends of peripheral nerves, thereby facilitating coaptation of fascicles in peripheral nerve repair.