Ikki Hamanaka

Evaluation of carpal canal pressure in carpal tunnel syndrome

Preoperative electrophysiologic testing and intraoperative carpal canal pressure measurements were performed on 957 hands in 647 patients with clinical signs of carpal tunnel syndrome. Fifty-five symptomatic hands in 48 patients were normal in both distal sensory latency and distal motor latency preoperatively. Carpal canal pressure was, however, significantly elevated compared to control data in all 55 hands. After complete subcutaneous release of the carpal canal using the Universal Subcutaneous Endoscope system, carpal canal pressure was reduced to within the normal control range. Clinical symptoms of carpal tunnel syndrome improved in all 55 hands. Postoperative electrophysiologic data remained within normal range in patients who agreed to receive electrophysiologic examinations.

Complete Endoscopic Carpal Tunnel Release in Long-Term Haemodialysis Patients

The roof of the carpal tunnel (or canal) consists of the distal portion of the flexor retinaculum, the flexor retinaculum (or the transverse carpal ligament) and the proximal portion of the flexor retinaculum. We tried to determine which anatomical structures were relevant to complete endoscopic carpal tunnel decompression in long-term haemodialysis patients with carpal tunnel syndrome. Carpal tunnel pressure was measured using the continuous infusion technique before and after endoscopic release of the flexor retinaculum, distal portion of the flexor retinaculum and the proximal portion of the flexor retinaculum respectively in 257 hands. We concluded that release of the distal portion of the flexor retinaculum, in addition to the flexor retinaculum, is essential for complete carpal tunnel decompression in long-term haemodialysis patients.

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.

Coracoacromial ligament release for shoulder impingement syndrome using the Universal Subcutaneous Endoscope system

We developed a new operative procedure of coracoacromial ligament release for shoulder impingement syndrome. The operative procedure was confirmed by cadaveric studies and applied to clinical cases in 40 shoulders of 37 patients who suffered from shoulder impingement without bony abnormalities. The subacromial space was observed under local anesthesia using the Universal Subcutaneous Endoscope (USE) system on an outpatient basis. A popping phenomenon was observed between the coracoacromial ligament and the greater tuberosity of the humerus, which was covered by the rotator cuff, and the coracoacromial ligament was resected with a rongeur under endoscopic visualization in all shoulders. Resection of the coracoacromial ligament relieved the impingement and clinical signs, as in open or arthroscopic resection of the coracoacromial ligament. Resection of the coracoacromial ligament using the USE system is a safe and less-stressful surgical invasion than open or standard arthroscopic resection of the coracoacromial ligament.

A NEW DIAGNOSTIC PROVOCATION TEST FOR CARPAL TUNNEL SYNDROME: OKUTSU TEST

Many authors have reported various clinical provocation tests for diagnosis of carpal tunnel syndrome, however, some tests cannot be administered correctly on patients who suffer from restricted wrist joint movement. We compiled positive rates from a new diagnostic provocation test (Okutsu test) carried out on 3474 hands, and compared them and their success rates with results from other provocation tests performed on these same hands. The Okutsu test positive rate was 72.4%. There were statistical differences between Phalen test (69.8%) and wrist-extension test (60.2%) results. The Okutsu test success rate was 99.9% and there were statistical differences between Phalen test (52.8%) and wrist-extension test (56.8%) results. There were no statistical differences between percussion test at the wrist results in positive rate (71.1%) and in success rate (99.7%). The Okutsu test positive rate is high and it serves as a reliable screening test for clinical diagnosis of carpal tunnel syndrome.

RESULTS OF ENDOSCOPIC MANAGEMENT OF PRIMARY VERSUS RECURRENT CARPAL TUNNEL SYNDROME IN LONG-TERM HAEMODIALYSIS PATIENTS

In long-term haemodialysis patients, carpal tunnel syndrome (CTS) frequently occurs as a result of amyloid deposition, originating from beta-2 microglobulin, to the flexor retinaculum, paratenons and tendons themselves, which leads to an increase in carpal canal pressure and compression of the median nerve. Surgical procedures can rectify the condition, but continuing maintenance haemodialysis sometimes causes recurrence. We endoscopically operated 1848 hands primarily, 104 recurrent post-endoscopic procedure hands and 130 recurrent post-open procedure hands using the Universal Subcutaneous Endoscope (USE) system, then analysed clinical symptoms and electrophysiological recovery for more than six months post-operatively. The patients were satisfied with the clinical results. Optimal electrophysiological improvements were reported. There were no statistical differences between three groups, except in recovery of touch sensation, which was better in the post-endoscopic group than in the post-open group. There were no complications in this series. Our minimally invasive endoscopic procedure, using the USE system, is safe and effective for primary and recurrent CTS in haemodialysis patients.

RETROSPECTIVE ANALYSIS OF FIVE-YEAR AND LONGER CLINICAL AND ELECTROPHYSIOLOGICAL RESULTS OF THE WORLD'S FIRST ENDOSCOPIC MANAGEMENT FOR CARPAL TUNNEL SYNDROME

We have analyzed postoperative long-term follow-up results of five years or more from idiopathic carpal tunnel syndrome patients that underwent our complete carpal canal release and decompression procedure that uses the Universal Subcutaneous Endoscope system. In this series, 203 hands were followed up both clinically and electrophysiologically. Final follow-up times were determined by the most recent electrophysiological measurements. Mean follow-up period was nine years. Tingling, pain (using a 3 gm needle) and touch (using a 2 gm von Frey hair) at all median nerve distribution areas recovered to normal in 92.9, 98.2, 95.2%, respectively. Abductor pollicis brevis muscle power improved from preoperative manual muscle testing of 0, 1, 2 to post-operative 4 or 5 in 82.6%. Mean detectable distal sensory latency improved from 4.3 (n = 130) to 3.1 msec (n = 200). Mean detectable distal motor latency improved from 6.2 (n = 189) to 4.1 msec (n = 200). Complication and recurrence rates were 0% and 0.5% respectively.

COMPARISON OF CLINICAL RESULTS BETWEEN ELDERLY AND YOUNGER PATIENTS FOLLOWING ENDOSCOPIC CARPAL TUNNEL RELEASE SURGERY FOR IDIOPATHIC CARPAL TUNNEL SYNDROME

We retrospectively analyzed clinical results of 107 hands of an elderly idiopathic carpal tunnel syndrome group (65 years old and older) and 234 hands of a younger group (under 65 years old) following endoscopic carpal canal release surgery. There were statistical differences in recovery rates for tingling, pain sensation and touch sensation (p < 0.01) and recovery periods of touch sensation (p < 0.05). There were no statistical differences in recovery rates, periods of thumb abduction muscle power, and recovery rates of electrophysiological examination results. Cervical spondylosis may affect postoperative recovery of subjective sensory disturbance, especially in the elderly group. From these results, in elderly patients we recommend primary minimally invasive endoscopic carpal canal release surgery and only apply primary opponoplasty in cases when the patient strongly wishes reconstruction faster than six months.

Endoscopic tarsal tunnel syndrome surgery using the Universal Subcutaneous Endoscope system

Background/objective Tarsal tunnel syndrome is a relatively rare entrapment neuropathy with the lateral and medial plantar nerves entrapped inside of the tarsal tunnel. When conservative treatment fails, standard open decompression of the nerve can be achieved by releasing the flexor retinaculum of the foot through a several-centimetre-long skin incision made along the tarsal tunnel. By contrast, we made a 1-cm portal incision at the proximal part of the medial ankle, and endoscopic tarsal tunnel release of the flexor retinaculum of the foot and part of the abductor hallucis muscle was achieved using the Universal Subcutaneous Endoscope (USE) system. Methods Our procedure was performed under local anaesthesia without a pneumatic tourniquet on an outpatient basis. The USE system was inserted into the tarsal tunnel at the proximal part of the medial ankle; the nerves, vessels, flexor retinaculum, tendons of the foot, and the abductor hallucis muscle were then endoscopically identified. Decompression of the lateral and medial plantar nerves entrapped inside of the tarsal tunnel was then achieved by releasing the flexor retinaculum of the foot and part of the abductor hallucis muscle with a push knife under complete endoscopic observation. Results Results from eight feet of five patients were compiled and analyzed. All showed improved clinical signs compared with their preoperative condition. Conclusion Our less invasive endoscopic management for tarsal tunnel syndrome using the USE system produces sufficient results.

Opponoplasty without postoperative immobilization.

Opponoplasty using tendon transfer is a useful reconstructive procedure that restores lost thenar muscle function. Tendon transfers, however, require postoperative immobilization periods of up to four weeks before the sutured tendons reach required strength. We developed an opponoplasty procedure using α-TCP (alpha-tricalcium phosphate) cement that does not require postoperative immobilization and was applied to nine hands out of nine cases. The procedure is performed under local anesthesia without a pneumatic tourniquet and on an outpatient basis. In this procedure, the flexor digitorum superficialis of the ring finger is used as the donor tendon and the palmaris longus tendon is used as a dynamic pulley. The distal end of the transferred tendon is anchored to the inside of a newly formed bone hole in the thumbs proximal phalanx using α-TCP cement. Our opponoplasty procedure was uneventful postoperatively and produced satisfactory results in all nine cases. The α-TCP cement procedure shows potential for other tendon transfer applications.