Measurement of carpal canal and median nerve pressure in patients with carpal tunnel syndrome

Carpal tunnel syndrome is a compression neuropathy wherein the median nerve is compressed inside of the carpal canal. Its diagnosis is made clinically, electrophysiologically, and sometimes by carpal canal pressure measurement. The objective of surgical management of this condition is the decompression of the median nerve. We usually measure carpal canal pressure preoperatively and postoperatively using a continuous infusion technique for diagnoses as well as for postoperative evaluation of decompression following our Universal Subcutaneous Endoscope system procedure. To evaluate whether our procedure effectively decompressed the median nerve, we measured intraneural pressure preoperatively and postoperatively in the resting position, with active power grip, and in the Okutsu test position. Correlation between the carpal canal pressure and intraneural median nerve pressure was statistically analyzed using the Kendall rank correlation coefficient (n = 157 hands). A significant correlation was present preoperatively in resting position and postoperatively with active power grip and in the Okutsu test position. Because of this correlation, we conclude that our endoscopic operative procedure effectively decompresses the median nerve and that simple carpal canal pressure measurement is sufficient to confirm diagnoses and to evaluate the status of postoperative decompression.     

大鼠正中神经修复后不同时段的电生理变化与神经再生的相关性分析

目的 探讨大鼠正中神经切断缝合后的不同时段,其复合神经动作电位(CNAP)与形态学方面的特点及其相关性分析.方法 在大鼠上臂正中神经中段切断缝合后的不同时间点(2、3、4、6、8和12周)进行CNAP检测,随后取正中神经组织进行形态学检查.结果 术后第2周可以记录到CNAP.术后再生神经记录的CNAP幅度比对照组显著减低(P<0.01),波幅下面积(Area)也显著低于对照组(P<0.01),传导速度(CV)显著慢于对照组(P<0.01).术后2～6周的潜伏期(Lat)均比对照组明显延长(P<0.05);术后2～8周刺激强度,即阈强度(THI)和超大刺激强度(SSI)显著低于对照组.CNAP的第一峰波幅(FPA)、峰-峰波幅(PPA)、Area、CV变化趋势为随时间增加而逐渐增高,而其参数Lat、THI、SSI随时间增加而逐渐降低.神经修复后2周缝合口远端已有少量的新生轴突,随着再生时间延长,越来越多的再生轴突延伸至远端.远端记录的CNAP波幅与其有髓神经纤维计数之间有强的正相关(相关系数为0.953).线性回归分析表明,存在线性关系.术后8周髓鞘趋向于成熟.结论 CNAP是早期诊断和评价损伤神经再生程度的良好指标.正常正中神经的CNAP波幅可能与有髓神经纤维的计数呈线性关系.术后第8周,CNAP参数趋向于稳定,神经髓鞘渐趋向于成熟.

Abstract：

Objective To explore the characteristics of compound nerve action potential (CNAP) after rat median nerve transection and repair,and their correlation with neuromorphometry at various time points. Methods The median nerve was transected and sutured at mid-arm level. At various time points from 2 to 12 weeks postoperatively,CNAP recording was performed and the median nerve was harvested for morphological examination. Results CNAP could be recorded at 2 weeks after nerve repair. The CNAP amplitude,the area below the curve (Area) and conduction velocity (CV) of regenerated nerve were significantly lower than those of control group (P＜0.01). From 2 weeks to 6 weeks postoperatively,CNAP latency (Lat) was obviously longer than normal (P＜0.05). From 2 weeks to 8 weeks postoperatively,CNAP stimulus intensity (threshold intensity and the supramaximal stimulation intensity,THI and SSI) was significantly lower than that of the control group (P＜0.01). First peak amplitude (FPA),peak-peak amplitude (PPA),Area and CV of CNAP increased with time,while parameters such as Lat,THI and SSI decreased over time in regenerated median nerve. Regenerated axons could be seen at 2 weeks after nerve transection and repair. More and more regenerated axons were seen with the lapse of time. There was a strong positive correlation between CNAP amplitude and the number of myelinated nerve fibers,with a 0.953 correlation coefficient. Linear regression analysis revealed the existence of a linear relationship. The maturity of regenerated nerve at 8 weeks reflected by myelin sheath thickness was close to that of a normal median nerve. Conclusion CNAP recording is a valuable tool to evaluate the extent of early nerve regeneration after nerve suture repair. There might exist a linear relationship between CNAP amplitude of normal median nerve and the number of myelinated nerve fibers. CNAP parameters are inclined to stabilize and nerve myelin sheath maturation is close to normal 8 weeks postoperatively.     

Median to radial nerve transfer for treatment of radial nerve palsy. Case report

The purpose of this study is to report a surgical technique of nerve transfer to restore radial nerve function after a complete palsy due to a proximal injury to the radial nerve. The authors report the case of a patient who underwent direct nerve transfer of redundant or expendable motor branches of the median nerve in the proximal forearm to the extensor carpi radialis brevis and the posterior interosseous branches of the radial nerve. Assessment included degree of recovery of wrist and finger extension, and median nerve function including pinch and grip strength. Clinical evidence of reinnervation was noted at 6 months postoperatively. The follow-up period was 18 months. Recovery of finger and wrist extension was almost complete with Grade 4/5 strength. Pinch and grip strength were improved postoperatively. No motor or sensory deficits related to the median nerve were noted, and the patient is very satisfied with her degree of functional restoration. Transfer of redundant synergistic motor branches of the median nerve can successfully reinnervate the finger and wrist extensor muscles to restore radial nerve function. This median to radial nerve transfer offers an alternative to nerve repair, graft, or tendon transfer for the treatment of radial nerve palsy.     

Long-term evaluation of rabbit peripheral nerve repair with end-to-side neurorrhaphy in rabbits

This study was designed to quantitatively assess long-term end-to-side neurorrhaphy in rabbits. The cut right ulnar nerve was repaired and sutured to the median nerve, in which a perineurial window was created in an end-to-side fashion 3 cm above the elbow joint. Both the extent of the reinnervation and the integrity of the intact donor nerve were evaluated in 36 rabbits randomly treated with fresh or delayed nerve repair. Evaluations included motor nerve conduction velocity (MNCV), dry muscle weight (DMW), and histological examinations at 9 and 12 months postoperatively. The recovery rates of MNCV were 90.1% and 92.8% for the ulnar nerve, and 95.7% and 96.8% for the median nerve, compared to intact contralateral nerves at 9 and 12 months, respectively. MNCV was not detectable for the ulnar nerve in control animals, while it was normal for the median nerve. Recoveries of flexor carpi ulnaris dry muscle weight of about 90.7% and 94.5% were observed at 9 and 12 months postoperatively, respectively. However, muscle mass measurements revealed a recovery of only 31.3% and 27% for control groups at 9 and 12 months postoperatively. The differences between experimental groups and control groups were statistically significant (P < 0.01). Neurofilament and silver stains showed numerous sprouting axons originating from the median nerve to the ulnar nerve. The results indicate that end-to-side neurorrhaphy could induce axonal sprouting from the main nerve trunk of upper limbs in rabbits, leading to useful functional recovery.     

Zur Morphologie des Karpaltunnels

The morphological correlation of the phenomenon of increased pressure in the carpal tunnel during wrist flexion and extension — as has been proved though measurements using wick-catheters — was studied in healthy subjects (n=15) and symptomatic patients with carpal tunnel syndrome (n=15). Our own measurements using magnetic resonance imaging (MRI) showed that there is a significant reproducible decrease in carpal tunnel diameter when the wrist is held in position of either flexion or extension. During flexion the diameter is decreased at the pisiformes and hamate level as well as it is lowered during extension at the pisiformes level. This might explain the rise in carpal tunnel pressure and thus the consecutive negative influence on the median nerve. Proximal swelling, distal flattening and increased signal intensity of the median nerve as well as the palmar bulging of the flexor retinaculum at the level of the hook of the hamate and at the level of the pisiformes were significantly higher in patients with carpal tunnel syndrom than in normal volunteers (from p<0.05 to p<0.001). In post-operative follow-up examinations of 13 patients with no clinic symptoms the distal flattening of the median nerve normalized in 94% within 3 months. The increased signal of the median nerve on T2-weighted images decreased postoperatively in 2/3 of the patients, whereas the motor latency of the median nerve recovered only in 39% of our patients who had 100% partial or complete clinical benefit. These findings imply that postoperative imaging may be helpful for evaluating the success or failure of surgical treatment.     

正中神经损伤修复后大脑运动皮层可塑性变化的实验研究

目的 研究正中神经损伤修复后运动皮层可塑性的变化过程.方法 SD大鼠35只,分为对照组和手术组,手术组又分为术后1 d和1周、4周、8周、12周、16周,每组5只,左侧肢体为损伤修复侧,将正中神经在内侧束分支以远2.0 cm处切断后缝合.通过皮层内微电极刺激技术,定量评价正中神经损伤恢复过程中运动皮层的可塑性变化.结果 正中神经屈指屈腕区运动皮层面积[(0.85±0.1)mm2,-x±s,下同].术后1 d、1周,对侧皮层正中神经屈指屈腕区被桡神经、肌皮神经、腋神经位点占据,没有无反应位点出现;术后4周、8周和16周,运动皮层出现无反应位点;术后8周、12周,对侧皮层出现屈指屈腕位点,差异有统计学意义(P＜0.05);术后16周,与健康组相比,差异无统计学意义(P＞0.05),运动皮层内没有无反应位点出现.结论 成年大鼠正中神经损伤后其对侧运动皮层发生可塑性改变,是一个动态的过程,但其机制还需进一步的研究.     

成年大鼠健侧颈7移位术后跨大脑两半球功能重组的脑电生理研究

目的研究健侧颈7移位至患侧正中神经术后初级运动皮层跨大脑两半球功能重组的时程,初步探讨该重组的中枢机制。方法将45只SD雄性大鼠随机分为9组,即正常对照组(1个组),加左侧全臂丛根性撕脱模型和右侧(健侧)颈7移位模型两组在术后3个月、5个月、7个月、10个月共8个时间组,每组5只。采用运动皮层内微电极电刺激技术,定量评价成年大鼠患肢正中神经代表区在双侧初级运动皮层(初级运动皮层,MI)内的可塑性变化。结果在双侧MI电刺激:(1)正常对照组:一侧肢体的正中神经代表区只在其对侧MI出现。(2)左侧全臂丛根性撕脱模型:在术后3～10个月,患肢的正中神经代表区在双侧MI均能被诱发出来。(3)健侧颈7移位模型:术后3个月,患肢正中神经代表区在双侧MI均未出现。术后5个月,患肢正中神经代表区仅出现于患肢同侧MI。术后7个月,患肢正中神经代表区在双侧MI均出现。术后10个月,患肢正中神经代表区只出现于患肢对侧MI,代表区面积与正常对照无明显差异,且仍位于原前肢代表区。结论在健侧颈7移位成年大鼠模型上证实,在术后10个月初级运动皮层出现了跨大脑两半球的功能重组,并初步探讨了其可能的中枢机制。发现了成年哺乳动物周围神经解剖通路改变后发生跨大脑半球功能重组的脑电生理依据。     

Motor Nerve Transfers to Restore Extrinsic Median Nerve Function: Case Report

Active pronation is important for many activities of daily living. Loss of median nerve function including pronation is a rare sequela of humerus fracture. Tendon transfers to restore pronation are reserved for the obstetrical brachial plexus palsy patient. Transfer of expendable motor nerves is a treatment modality that can be used to restore active pronation. Nerve transfers are advantageous in that they do not require prolonged immobilization postoperatively, avoid operating within the zone of injury, reinnervate muscles in their native location prior to degeneration of the motor end plates, and result in minimal donor deficit. We report a case of lost median nerve function after a humerus fracture. Pronation was restored with transfer of the extensor carpi radialis brevis branch of the radial nerve to the pronator teres branch of the median nerve. Anterior interosseous nerve function was restored with transfer of the supinator branch to the anterior interosseous nerve. Clinically evident motor function was seen at 4 months postoperatively and continued to improve for the following 18 months. The patient has 4+/5 pronator teres, 4+/5 flexor pollicis longus, and 4−/5 index finger flexor digitorum profundus function. The transfer of the extensor carpi radialis brevis branch of the radial nerve to the pronator teres and supinator branch of the radial nerve to the anterior interosseous nerve is a novel, previously unreported method to restore extrinsic median nerve function.     

Postoperative edema after vascular access causing nerve compression secondary to the presence of a perineuronal lipoma: case report

OBJECTIVE AND IMPORTANCE: Median nerve neuropathy can be clinically devastating to a patient. It can be caused by compression of the median nerve anywhere along its course. We present the case of delayed median nerve neuropathy after the placement of a vascular graft in the arm. CLINICAL PRESENTATION: An arm shunt was placed in the nondominant upper extremity in a 60-year-old man with end-stage renal disease. Twelve hours postoperatively, the patient developed neurapraxia in the median nerve distribution in the hand. INTERVENTION: Exploration of the arm revealed a lipoma coursing along and deep to the median nerve. Resection of the lipoma decompressed the nerve. CONCLUSION: In this patient, median nerve neuropathy was caused by a lipoma and postoperative swelling from placement of the vascular graft. The swelling that occurred after the shunt placement unmasked subclinical compression of the nerve by a lipoma deep to the median nerve. To our knowledge, this report is unique in documenting damage to the median nerve after vascular graft placement as a result of an occult mass.     

Transfer of brachialis branch of musculocutaneous nerve for finger flexion: anatomic study and case report

Based on an anatomic study, a transfer of the brachialis muscle branch of the musculocutaneous nerve (BMBMCN) to finger flexor functional fascicles of the median nerve was designed. Preliminary results of clinical application of this new procedure are reported. Dissection of 32 cadaver upper limbs revealed that BMBMCN derives from the musculocutaneous nerve at the distal 1/3 upper arm level. Mostly it is of single-branch type, with an average dissectable length of 5.2 cm. At this level, functional fascicles of finger flexors are located at the posterior 1/3 of the median nerve. BMBMCN can be directly coapted to these finger flexion fascicles. In one case of brachial plexus lower trunk injury, this neurotization procedure was done. No impairment of elbow flexion and wrist flexion was found postoperatively. Recovery of finger and thumb flexion was seen 1 year postoperatively. This neurotization is safe and effective for treating lower trunk injuries.     

Lipofibromatous hamartoma of the median nerve

Lipofibromatous hamartoma of the nerve is a very uncommon, congenital, benign, peripheral nerve tumor. It is mostly encountered in the extremities of young adults, involving the median nerve in the majority of cases. The nerve tissue is infiltrated by diffuse fibroadipose tissue which dissociates the fasciculi without invasion. Patients with lipofibromatous hamartoma of the median nerve usually present with symptoms of carpal tunnel syndrome, usually accompanied by marked macrodactyly. Lipofibromatous hamartoma of the median nerve was encountered in an 18-year-old female patient, involving the wrist, causing macrodactyly of the index finger, and resulting in symptoms of carpal tunnel syndrome. Median nerve release and partial excision of the adipose tissue along the mass were performed. Fourteen months postoperatively, the patient had no complaints and the mass decreased in size without any motor or sensory functional losses.     

Iatrogenic Pronator Syndrome

A case of congenital radio-ulnar synostosis with functional disability due to fixation of the forearm in maximal pronation was operated on with a rotational osteotomy in the proximal third of the forearm. Within four days postoperatively a total paralysis of the median nerve gradually developed. The median nerve was therefore explored and found to be strongly compressed by the stretched pronator teres and the superficialis bridge which were sectioned. Full motor and sensory recovery gradually occurred.     

灵长类去细胞神经的萃取制备及异体移植后早期神经再生观察

目的发展新的化学处理方法，清除灵长类周围神经中的细胞和髓鞘，降低其抗原性，萃取粗大和长段的去细胞神经移植物，并观察其同种异体移植的早期神经再生。方法以Triton X-100和脱氧胆酸钠溶液化学处理猴长段正中神经和坐骨神经。萃取的去细胞神经行普通组织学染色、免疫组化染色及透射电镜检查，观察其组织结构。以去细胞神经同种异体移植修复猴正中神经3．0cm和胫神经5、0cm缺损，术后3周和8周，通过大体观察、HE染色及免疫组化染色观察早期神经再生一结果细胞和髓鞘已被彻底清除，神经基底膜和雪旺细胞基底板层保留完好，去细胞神经成为空的神经基质管。移植术后8周轴突再生已通过远端吻合口，移植段再血管化及雪旺细胞增殖良好。结论该化学处理可萃取灵长类粗大和长段的去细胞神经，作为同种神经移植物不会被排斥吸收。     

A comparative experimental study of vascularized and nonvascularized nerve grafts

In order to compare vascularized and nonvascularized nerve grafts in a normal bed, 96 median nerve grafts were performed in rabbits. The median nerves were grafted in situ bilaterally, whether vascularized or nonvascularized. The length of the grafts was 2 cm, 4 cm, or 6 cm. A morphometric study was performed eight weeks and 24 weeks after the operation. No significant differences were found between vascularized and nonvascularized grafts at the same levels of nerve grafts. However, significant differences between vascularized and nonvascularized grafts were found for 4-cm and 6-cm grafts at eight weeks, and for 6-cm grafts at 24 weeks postoperatively, comparing the proximal normal nerve segments with the nerve segments distal to the nerve grafts.     

Opening wedge osteotomy for malunion of the distal radius with neuropathy:13 cases followed for 6 (1-11) years

13 patients with malunion of the distal radius after Colles' fractures and electroneurographically verified median nerve compression underwent an opening wedge osteotomy without a simultaneous release of the transverse carpal ligament. 12 patients had reduction of the typical night pain with normal or almost normal sensibility within the first 2 months. In 1 patient a release of the carpal ligament was necessary after 6 months. 6 years postoperatively all patients had acceptable wrist function with normal function of the median nerve in all but one.     

Nerve transfer to the median nerve using parts of the ulnar and radial nerves in the rabbit--effects on motor recovery of the median nerve and donor nerve morbidity

In this study, motor re-innervation of the median nerve by transfer of one-third, one-half, and two-thirds of either the agonistic ulnar nerve or the antagonistic radial nerve was investigated in both extremities of 20 rabbits. Recipient median nerve: Muscle contraction force of the flexor digitorum sublimus muscle after a one-third and a one-half of the ulnar nerve transfer achieved an average of 75 and 97% muscle power respectively as compared to conventional end-to-end neurorrhaphy. Muscle contraction force after one-third or one-half of the radial nerve transfer was significantly lower (36%). Donor nerves: Extensor carpi radialis muscle or flexor carpi ulnaris muscle contraction force 6 months postoperatively demonstrated a significant decrease after a one-half ulnar nerve and a two-thirds ulnar or radial nerve transfer, but not after a one-third transfer of either radial or ulnar nerves. Histologically, the number of axons in the re-innervated median nerve and both donor nerves distal to the coaptation site seemed to follow variable patterns. It was concluded that in the rabbit use of one-third of the agonistic ulnar nerve for re-innervation of the median nerve results in useful motor recovery with negligible donor site morbidity. Clinically, this technique may offer an alternative option for proximal nerve injuries or for free functioning muscle transplantations.     

Common peroneal nerve dysfunction after high tibial osteotomy

We assessed 16 patients before and after high tibial osteotomy by electrophysiological recordings, creatine phosphokinase levels, radiographs and intracompartmental pressure monitoring. We found mild electrophysiological abnormalities pre-operatively in 12 of the 16 patients, but postoperatively these had deteriorated in 11 of the 14 patients studied. Creatine phosphokinase levels, compartment pressure and radiological deformity were not predictive of the development of postoperative common peroneal nerve palsy. Patients who also had a proximal fibular osteotomy had greater electrical abnormalities postoperatively and two of them developed common peroneal palsies. Proximal fibular osteotomy appears to be a causative factor in the development of common peroneal nerve palsy; more work is needed on the blood supply of the nerve.     

腕管综合征术前肌电指标与术后早期疗效的相关性分析

目的探讨腕管综合征术前肌电指标与术后早期疗效的相关性.方法将50例患者术前肌电检测值分为轻、中、重3组并进行评分及分组.术后3个月复查,疗效按Kelly评定方法评分.将术前肌电检测值与术后疗效进行相关性分析.结果正中神经感觉传导速度轻度组术后拇指到腕较术前增加21.5%,中指到腕增加16.3%.中度组术后拇至腕较术前增加17.7%,中指到腕增加21.9%.重度组术后正中神经末端CMAP潜伏期较术前加快28.6%.3组肌电指标术前、后相比差异均有显著性意义(P＜0.05).术前肌电指标组合分组与术后早期疗效评分之间做Spearman等级相关分析,两者呈显著负相关(rs'=-0.6172,P＜0.001).结论术前肌电指标组合分组可以作为术后早期疗效的预测指标.     

健侧颈7神经根移位修复多条神经模型的建立及功能恢复动态观察

目的比较七种不同术式的健侧颈，神经根移位术后受体神经的功能以探讨颈，神经重建多组神经的可行性。方法SD大鼠105只，随机分为7组，每组15只。建立传统的健侧颈，移位经尺神经近端（单根）接正中神经或肌皮神经或桡神经（A、D、G组），健侧颈，经尺神经近端（2股，合干法）接正中、肌皮神经或正中、桡神经（B、E组），健侧颈，经尺神经及腓肠神经（分干法）接正中、肌皮神经或正中、桡神经（C、F组）。术后观察患肢功能，抓握力及梳洗动作出现时间。结果术后2个月，修复正中和肌皮神经的B、C组，均出现主动屈趾、屈肘功能。抓握力比较：合干法（B、E组）、分干法（C、F组）及传统法（A、D、G组）的差异均有统计学意义（P〈0．05）。术后3、6个月合干、分干法与传统法比较差异无统计学意义（P〉0．05）。梳洗试验出现时间：合干、分干法及传统法比较差异无统计学意义（P〉0．05）。结论颈，神经根能提供足够的神经再生纤维，可同时恢复2条神经功能。     

Giant median nerve in bilateral carpal tunnel syndrome

We introduce a middle age healthy man with sequential bilateral carpal tunnel syndrome. At the surgery, we encountered a wide median nerve in both wrists. Although enlargement of median nerve in carpal tunnel has been well documented, 25 mm width of the nerve is a rare scene, underscoring that leaving the nerve under the unyielding pressure would lead to a fibrous atrophic median nerve.KEY WORDS: Blood-nerve barrier, carpal tunnel syndrome, compressive neuropathy, median nerve, neural edema