Background Carpal tunnel syndrome is the most common compressive peripheral neuropathy,which is a couple of clinical syndromes caused by the oppression of the median nerve in the carpal tunnel.The tough of the transverse carpal ligament and thickness of its edge are the major factors in the oppression of the median nerve.Under normal circumstances,there is a large amount of tendon synovial in the carpal tunnel,which plays a role of nutrition and lubrication to the nerve.However,the tendon synovial hyperplasia,or even congestion and edema can cause or aggravate the oppression of the median nerve.Also,it will cause an inflammatory stimulate to the nerve.The major clinical manifestations of carpal tunnel syndrome are numbness and pain of three and a half fingers of the radial side.Usually,the pain radiates to the hand and forearm,accompanied with dysfunction of thumb opposition,thenar muscle atrophy and decreased grip and pinch strength.But in the synovial hyperplasia carpal tunnel syndrome,because of increased congestion at night and reflux disorder,there will be a significant night pain and numbness,which sometimes even makes the patients awake at a fixed time at night.These are the typical symptoms of synovial hyperplasia carpal tunnel syndrome.When the patients wake up,many will activate the fingers and wrists to relieve the pain,which promotes the synovial reflux in the carpal tunnel and reduces the pressure of carpal tunnel.As such reasons,there will be a phenomenon that clinical manifestations in the resting state do not fully meet the electrophysiological examination after activity.Patients who were diagnosed as synovial hyperplasia carpal tunnel syndrome were admitted to our hospital. We performed transverse carpal ligament release, carpal tunnel decompression, synovial tissue removal and median nerve release. The purpose of this study is to describe clinical characteristics of synovial hyperplasia carpal tunnel syndrome and analyzes the outcome of treatment method adopted in this study.Methods There were 63 patients (75 sides,left of 27 cases and right of 48 cases;51 cases of one-side and 12 cases bilateral;16 males and 47 females;aged 40-82 years,mean 62 years old;course of disease differ from 3 months to 8 years) included in the group.The time between onset of symptoms to treatment time differed from 3 weeks to 2 years.The etiology of the disease was as follows:49 cases caused by chronic injury,14 cases caused by autoimmune diseases (mostly bilateral) such as rheumatoid arthritis,gout,Sjogren syndrome and so on.There was no patient with a history of wrist trauma,fracture or dislocation.Also,there was no wrist tumor.The main symptoms of patients were wrist pain,numbness,weakness of grip and pinch and wake up at night caused by pain,which may radiated to the elbow and shoulder and had a relief by shaking the involved hands.The examination is as follows:wrist Tinel sign positive,paresthesia of three and a half fingers of the radial side and thenar muscle atrophy.The preoperative neurophysiological testing includes median nerve motor conduction velocity,sensory conduction velocity,motor distal latency and sensory distal latency.All patients received conservative treatment like preoperative non-steroidal anti-inflammatory drugs,local physical therapy and carpal tunnel drug injections.The treatment received a varying relief but soon the symptoms recurred,which affected the quality of life of patients so much that they came to the hospital to receive surgery.All patients underwent severing of transverse carpal ligament,synovial removal of the carpal tunnel and release of the median nerve.Procedures:All patients were narcotized with brachial plexus anesthesia,and then we will make the patient supine,limb abduction.Use the tourniquet and turn the pressure at 300 mmHg.Disinfection and drape routinely,and then make an arc-shaped incision between the midpoint of thenar crease to the wrist crease line,which is 3 cm long.After cutting the skin,subcutaneous tissue and fascia layer of the palm,cut the transverse carpal ligament at the level of the wrist crease line.We should cut the transverse carpal ligament proximally under direct vision.In the process,we should prevent damage to the underlying median nerve until the transverse carpal ligament is fully cut.At the midpoint thenar crease and beyond care should be taken to avoid damage to the recurrent branch of the median nerve.During the operation,we can see:the transverse carpal ligament thickened;median nerve is compressed under the transverse carpal ligament;the nerve becomes flat and the outer membrane thickened;the color of the compressed part is dark;visible neurovascular interruption;nerve surrounded by scars;flexor digitorum deep tendons and flexor digitorum superficial tendons are wrapped by a large amount of synovial tissue.After cutting the transverse carpal ligament,separate the median nerve and decide whether to release the outer membrane according to degree of nerve entrapment and hyperplasia.If releasing the outer membrane of nerve is decided,release the hyperplasia tissue around the nerve using microsurgical scissors,cut the involved out membrane of median nerve longitudinally until soft normal nerve is revealed,which means a complete release.Protect the median nerve strictly;separate the flexor digitorum deep tendons and flexor digitorum superficial tendons;carefully remove the hyperplastic lesions of synovial tissue.Loose the tourniquet,stanch strictly,indwell drainage strip,suture the fascia layer of the palm and then make a full thickness suture.The resected synovial tissue surrounding the tendon should be sent to receive a pathologic examination.Postoperative treatment:Drainage strip should be removed within 24 hours after surgery;do the finger flexion and dorsiflexion activities under the guidance of a doctor to prevent tendon adhesions;elevate the affected limb at night to reduce swelling;stitches the wound 14 days after surgery;take methycobal for 3 weeks;exercise normally 4-6 weeks after surgery.Clinical criteria:We use the Kelly standard to evaluate the effect of treatment 3 months after surgery.The details are as follows:excellent:the symptoms disappeared completely;good:the symptoms were relieved significantly;general:symptoms become mild or continued;poor:symptoms unchanged or be worse.All patients received neurophysiological testing during follow-up.Statistical Analysis:The data is statistically analyzed using SPSS software.We use two independent samples t-test analysis and make P<0.05 significant differences.Results There are a total of 46 patients (50 sides) who received a more than 3 months clinical follow-up and the average time of follow-up is 4.6 months.The symptoms of hand numbness,pain all had a varying relief and the symptom of anesthesia at night disappeared.The Incision healed well,and there was no long-term complications such as infection and nonunion.There was no scar contracture.No one complained of recurrence 3-12 months after operation.No patient was present with injury of median nerve,the superficial palmar arch or recurrent branch of the median nerve.During the operation,we can see the synovial tissue hyperplasia around the median nerve,which cause the compression of the median nerve.The postoperative pathological examination shows edema and degeneration of the fibrous connective tissue around the median nerve,hyperplasia of the synovial tissue,infiltration of the lymphocyte and plasma cells.Preoperative electrophysiological tests showed there is no significant reduction of median nerve motor or sensory conduction velocity,(48.32±3.68) m/s and (46.32±3.68) m/s,respectively.There are 50 sides which received electrophysiological tests 3 months after operation and the tests showed that the median nerve motor and sensory conduction velocities were bigger than the preoperative velocities,(51.64±2.70) m/s and (50.11±3.47) m/s,respectively.There is a significant difference(t=-6.095,-2.935,all P<0.05).The median nerve motor distal latency of (4.38±0.40) ms is reduced to (3.47±0.27) ms,and the sensory distal latency of (5.12±0.36) ms is reduced to (4.14±0.31) ms,with a significant difference(t=15.895,16.011,all P<0.05).According to the Kelly standard,there are 32 sides of excellent,whose night pain and numbness of the fingers disappeared completely;there are 14 sides of good,whose night pain,numbness of the fingers relieved significantly than before but not completely disappeared;there are 4 sides of general and no side of poor.Over all,the proportion of excellent is 92%.Conclusions As a summary,from the data of this 46 patients (50 sides) with synovial hyperplasia carpal tunnel syndrome,we can see that the main clinical manifestations of synovial hyperplasia carpal tunnel syndrome are pain,numbness and inability to grip at night,paresthesia of three and a half fingers in the radial sides.The neurophysiological examinations show neurogenic damage,mild decrease of nerve conduction velocity.The way of transverse carpal ligament revering,synovial removal within the carpal tunnel and median nerve release therapy can achieve a good result.