Fluorescein Angiography for Monitoring Neural Blood Flow in Chronic Nerve Compression Neuropathy: Experimental Animal Models and Preliminary Clinical Observations.

Pathologies associated with neural blood disturbance have been reported in patients with chronic nerve compression (CNC) neuropathy. Fluorescein angiography (FAG) and laser Doppler flowmetry (LDF) are effective for real-time peripheral nerve blood flow assessment. However, their reliability in severe neuropathy models in large animals or clinical conditions remains unclear. Initially, we aim to apply FAG to two different CNC animal models and evaluate their characteristics in comparison with those of LDF. In FAG, we quantified the peak luminance at the compression site following fluorescein injection. Then, we positioned the LDF probe at the center of the compression site and recorded the blood flow. Subsequently, we analyzed whether the FAG characteristics obtained in this animal experiment were consistent with those of clinical studies in patients with severe carpal tunnel syndrome (CTS). In the CNC rat model, FAG and LDF effectively monitored reduced neural blood flow over time. We observed significant blood flow reduction using both techniques in a newly developed severe CNC rabbit model. Notably, FAG correlated strongly with the compound muscle action potential (CMAP) amplitude in electrodiagnostic findings, unlike LDF. As a next step, we performed FAG after open carpal tunnel release in clinical cases of CTS. FAG correlated significantly with preoperative CMAP amplitude. This indicates FAG's importance for assessing nerve blood flow during surgery, potentially improving diagnostic accuracy and surgical outcomes.

Limited Flexion of the Middle Finger Due to a Degenerative Partial Flexor Tendon Rupture Mimicking a Soft Tissue Tumor.

Atraumatic subcutaneous rupture of the finger flexor tendon of the hand and forearm is rare. Most sites of closed and subcutaneous ruptures of the finger flexor tendon are the tendon-bone insertion and musculotendinous junction, and an intratendinous lesion is unusual. We report the case of a 76-year-old female who presented to our department with a one-month history of a soft tissue mass and limited flexion of the left middle finger without trauma. Preoperative magnetic resonance imaging revealed a soft tissue mass that caused limited finger flexion. Intraoperative findings showed an intratendinous rupture of the flexor digitorum profundus tendon at the middle phalanx; the lesion was resected to obtain smooth grinding of the tendon. One year postoperatively, the soft tissue mass and limited flexion of the finger resolved without recurrence.

Nerve Grafting for Isolated Injury to the Intrinsic Motor Branch of the Ulnar Nerve due to a Stab Injury: A Case Report.

Isolated injury to the deep motor branch of the ulnar nerve caused by stabbing is sporadic, with only one reported case in the English-language literature. We report one such case treated successfully using nerve grafting. A 33-year-old patient had sustained a stab wound to the right hypothenar eminence and showed a claw hand deformity. Needle electromyography study revealed denervation potentials with no voluntary motor unit action potentials (MUAPs) in the first dorsal interosseous (FDI) muscles. Nerve exploration revealed a neuroma-in-continuity in the intrinsic motor branch of the ulnar nerve. Intraoperative nerve stimulation confirmed the absence of compound muscle action potentials in the FDI. The damaged scarred nerve was resected, and the 15-mm defects were reconstructed with cable autografting. Two years and 5 months after the surgery, voluntary MUAPs were observed in the FDI. The pinch strengths recovered. Laceration of the deep branch of the ulnar nerve caused by stabbing can sometimes remain hidden as the hand sensation remains intact. Pre- and intraoperative electrophysiological examination is essential to assess the severity of the injured nerve and determine an appropriate surgical option. Even nerve grafting can facilitate satisfactory results as target intrinsic muscles are quite close to the repair site.

Computed Tomography Evaluation of Distal Screw Penetration in Volar Locking Plate Fixation for Intra-Articular Distal Radius Fractures.

PURPOSE: Volar locking plate fixation for distal radius fractures (DRFs) is a technically demanding procedure with a risk of distal screw penetration through the dorsal cortex or the articular surface. This study aimed to investigate the incidence and details of distal screw penetration after volar locking plate fixation for intra-articular DRFs using a CT scan and to evaluate the relationship between the incidence of screw penetration and fracture comminution severity and the clinical complications of screw penetration. METHODS: This was a retrospective case series of 91 adult patients (mean age, 63 years; 27 men) who underwent volar locking plate fixation for intra-articular DRFs from 2015 to 2018. The positioning of the distal screws was evaluated using a postoperative CT scan, and radiological outcomes were compared between the AO C1 and C3 groups. At the final follow-up, tendon rupture and arthritis severity were assessed as clinical complications of dorsal and intra-articular screw penetration. RESULTS: Distal screw penetration was observed in 44 wrists (48%), dorsal cortex screw penetration in 34, intra-articular screw penetration in 13, and both dorsal cortex and intra-articular screw penetration in three. The incidence of intra-articular screw penetration was significantly higher in the C3 group than in the C1 group. No tendon rupture was observed. Multivariable analysis revealed that intra-articular screw penetration was significantly related to high severity of arthritis. CONCLUSIONS: Approximately half of the study patients with intra-articular DRFs had distal screw penetration. The incidence of intra-articular screw penetration was associated with the severity of fracture comminution, and the intra-articular screw penetration was associated with the incidence of early radiocarpal arthritis. Intra-articularly penetrating screws should be replaced as soon as they are discovered, regardless of the length of penetrated screw or absence of patients' subjective symptoms. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Arthroscopic Reduction and Internal Fixation for Peritrapezium Traumatic Axial Carpal Dislocation: A Case Report.

Axial carpal dislocations and fracture-dislocations are rare injuries involving derangement of the carpal arches. Several surgical approaches have been reported as a means of treatment, including the use of closed or open reduction and internal fixation. However, to our knowledge, surgical treatment using arthroscopy has not been reported so far. Here we present the case of a 54-year-old man who experienced peritrapezium axial carpal dislocation while reversing his car. Minimally invasive surgery using arthroscopy was performed because of severe swelling of the hand. Reduction under arthroscopic assistance using midcarpal portals was performed based on the relationship between the trapezium and trapezoid, and fixed wires were inserted. Wires were removed at six weeks postoperatively, and range-of-motion exercises of the wrist joint were started. At one-year postoperative follow-up, the patient was asymptomatic, with no difficulties while performing daily activities and work. Computer tomography images revealed an anatomical carpal arch without traumatic arthrosis. Arthroscopy-assisted surgery enabled us to anatomically reduce fracture-dislocation of the trapezium and assess the injury path.

Nerve-End Capping Treatment with a Polyglycolic Acid Conduit for Rat Sciatic Neuroma: A Preliminary Report.

BACKGROUND: The treatment of painful neuroma remains challenging. Recently, a nerve-end capping technique using a bioabsorbable nerve conduit was newly introduced to treat amputation neuroma. A collagen-coated polyglycolic acid (PGA) conduit has been commercially available for the reconstruction of peripheral nerve defects, yielding successful clinical outcomes. However, no experimental research has been conducted using this PGA nerve conduit as capping device for treating amputation neuroma. The purpose of this study was to investigate nerve-end capping treatment with the PGA conduit in the rat sciatic nerve amputation model, focusing on histological scar formation and neuroinflammation. METHODS: Forty-seven rats were divided into two groups: no capping (transected nerve stump without capping; n = 25) and capping (nerve-end capping with collagen-coated PGA nerve conduit; n = 22). Twelve weeks after sciatic neurectomy, neuropathic pain was evaluated using the autotomy score. Stump neuromas were histologically evaluated or perineural scar and neuroinflammation. RESULTS: While autotomy scores gradually exacerbated in both groups, they were consistently lower in the capping group at 4, 8, and 12 weeks postprocedure. Twelve weeks after surgery, the transected nerve stumps in the no-capping group had formed macroscopic bulbous neuromas strongly adhering to surrounding tissues, whereas they remained wrapped with the PGA nerve conduits loosely adhering to surrounding tissues in the capping group. Histologically, distal axonal fibers were expanded radially and formed neuromas in the no-capping group, while they were terminated within the PGA conduit in the capping group. Perineural scars and neuroinflammation were widely found surrounding the randomly sprouting nerve end in the no-capping group. In capped counterparts, scars and inflammation were limited to closely around the terminated nerve end. CONCLUSION: Nerve-end capping with a collagen-coated PGA conduit after rat sciatic neurectomy might prevent neuroma formation by suppressing perineural scar formation and neuroinflammation around the nerve stump, potentially relieving neuropathic pain.

Is Repair of a Small Coronoid Fracture Required in the Surgical Treatment of Terrible Triad Injury of the Elbow?

Background: Multiple treatment protocols have been described in literature for the treatment of terrible triad injury (TTI) of the elbow. We believe that repair of the medial collateral ligament (MCL) should be performed in preference to repair of a small coronoid fracture if the elbow is unstable after fixation/replacement of the radial head and repair of the lateral collateral ligament (LCL). The aim of this study is to report the outcomes of surgical treatment of patients with TTI associated with a small coronoid fracture in whom the coronoid fracture was not addressed. Methods: This study is a retrospective case series of 12 consecutive patients who underwent surgery for acute TTI with a small coronoid fracture (9 Regan-Morrey type I and 3 Regan-Morrey type II). Ten patients had complete MCL injuries. All patients underwent repair of the torn LCL and MCL and treatment of the radial head. The coronoid fracture was not surgically treated. At the final follow-up, the range of motion, degree of flexion contracture, Mayo elbow performance score (MEPS) and Disabilities of the Arm, Shoulder and Hand (DASH) were measured. Results: The mean follow-up period was 13.5 months. At the final follow-up, the mean arc of elbow flexion was 132° and the mean flexion contracture was 10°. The mean arc of forearm rotation was 148°. None of the patients demonstrated elbow instability. The mean MEPS was 92.5 points with seven having excellent results and five having good results. The average DASH score was 11.2 points. Conclusions: Our results showed that good elbow stability, arc of motion and clinical outcomes could be achieved without repair of small coronoid fractures in the treatment of TTI. The repair of MCL injuries should be given priority over the fixation of small coronoid fractures to regain elbow stability. Level of Evidence: Level IV (Therapeutic).

Pain and numbness one month after carpal tunnel release predict patient-reported outcome measures at sixth months.

A number of outcome predictors for carpal tunnel release (CTR) for carpal tunnel syndrome (CTS) have been reported. However, some predictors are controversial, and few studies have referred to the early postoperative outcome prognostic factors after CTR. The aim of this study was to investigate whether pain and numbness at 1 month post-CTR were early postoperative predictors of clinical outcomes 6 months after surgery. Pain and numbness were evaluated using the visual analog scale (VAS) preoperatively and at 1 month post-surgery. Patient-reported outcome measures (PROMs), including the Quick Disabilities of the Arm, Shoulder and Hand (QDASH) measure, the Hand20 questionnaire and the Boston Carpal Tunnel Questionnaire (BCTQ), were recorded for each patient 6 months after surgery. The BCTQ consisted of the Symptom Severity Scale (SSS) and Functional Status Scale (FSS). Multivariable linear regression analysis was performed to investigate the association between the VAS scores and PROMs. We retrospectively identified 93 patients who underwent open carpal tunnel release (OCTR) or endoscopic carpal tunnel release. The mean age of the patients was 67.5 years, and 67 patients (72.0%) were female. Sixty patients were treated by OCTR (65.0%). With multivariable linear regression analysis, we found that pain and numbness, evaluated with VAS 1 month post-surgery had significant correlations with QDASH, Hand20, SSS and FSS 6 months after surgery. In conclusion, pain and numbness 1 month after CTR predict PROMs at 6 months.

Nerve capping treatment using a bioabsorbable nerve conduit with open or closed end for rat sciatic neuroma.

BACKGROUND AND AIMS: Nerve capping treatment using bioabsorbable nerve conduits has recently been introduced for painful amputation neuroma. However, no clinical or experimental data are available for comparing nerve conduits with open distal ends and closed distal ends. Here, we investigated the nerve conduit with open or closed distal ends as the superior capping device, using a commercially available polyglycolic acid (PGA) nerve conduit in a rat sciatic nerve amputation model. METHODS: Ninety-one rats were assigned to three groups: no-capping (n = 30), capping the resected nerve stump with open ends (n = 31), and closed-end nerve conduits (n = 30). Twelve weeks after sciatic neurectomy, with or without capping, the evaluation of neuropathic pain using the autotomy score was performed. Stump neuromas with perineural scars and neuroinflammation were evaluated histologically. RESULTS: The mean autotomy scores in the closed-end nerve conduit group were significantly lower than those in the no-capping group. However, the difference between the open-end nerve conduit and the closed-end nerve conduit groups was insignificant. Histologically, distal axonal fibers expanded radially and formed neuromas in the no-capping group while they were terminated within the PGA conduit in both capping groups. In particular, the closed-end version of the PGA nerve conduit blocked scarring from intruding through the open end and protected the nerve stump with less neuroinflammation. Nerve capping with the closed-end version of the PGA nerve conduit most effectively suppressed perineural neuroinflammation and scar formation around the resected nerve stump. INTERPRETATION: Nerve capping with the PGA nerve conduit, particularly those with closed ends, after rat sciatic neurectomy prevented amputation neuroma and relieved neuropathic pain.

Long-term survival of transplanted induced pluripotent stem cell-derived neurospheres with nerve conduit into sciatic nerve defects in immunosuppressed mice.

Since the advent of induced pluripotent stem cells (iPSCs), clinical trials using iPSC-based cell transplantation therapy have been performed in various fields of regenerative medicine. We previously demonstrated that the transplantation of mouse iPSC-derived neurospheres containing neural stem/progenitor cells with bioabsorbable nerve conduits promoted nerve regeneration in the long term in murine sciatic nerve defect models. However, it remains unclear how long the grafted iPSC-derived neurospheres survived and worked after implantation. In this study, the long-term survival of the transplanted mouse iPSC-derived neurospheres with nerve conduits was evaluated in high-immunosuppressed or non-immunosuppressed mice using in vivo imaging for the development of iPSC-based cell therapy for peripheral nerve injury. Complete 5-mm long defects were created in the sciatic nerves of immunosuppressed and non-immunosuppressed mice and reconstructed using nerve conduits coated with iPSC-derived neurospheres labeled with ffLuc. The survival of mouse iPSC-derived neurospheres on nerve conduits was monitored using in vivo imaging. The transplanted iPSC-derived neurospheres with nerve conduits survived for 365 days after transplantation in the immunosuppressed allograft models, but only survived for at least 14 days in non-immunosuppressed allograft models. This is the first study to find the longest survival rate of stem cells with nerve conduits transplanted into the peripheral nerve defects using in vivo imaging and demonstrates the differences in graft survival rate between the immunosuppressed allograft model and immune responsive allograft model. In the future, if iPSC-derived neurospheres are successfully transplanted into peripheral nerve defects with nerve conduits using iPSC stock cells without eliciting an immune response, axonal regeneration will be induced due to the longstanding supportive effect of grafted cells on direct remyelination and/or secretion of trophic factors.

Bioabsorbable nerve conduits three-dimensionally coated with human induced pluripotent stem cell-derived neural stem/progenitor cells promote peripheral nerve regeneration in rats.

Peripheral nerve regeneration using nerve conduits has been less effective than autogenous nerve grafts. To overcome this hurdle, we developed a tissue-engineered nerve conduit coated with mouse induced pluripotent stem cell (iPSC)-derived neurospheres, for the first time, which accelerated nerve regeneration in mice. We previously demonstrated the long-term efficacy and safety outcomes of this hybrid nerve conduit for mouse peripheral nerve regeneration. In this study, we investigated the therapeutic potential of nerve conduits coated with human iPSC (hiPSC)-derived neurospheres in rat sciatic nerve defects, as a translational preclinical study. The hiPSC-derived quaternary neurospheres containing neural stem/progenitor cells were three-dimensionally cultured within the nerve conduit (poly L-lactide and polycaprolactone copolymer) for 14 days. Complete 5-mm defects were created as a small size peripheral nerve defect in sciatic nerves of athymic nude rats and reconstructed with nerve conduit alone (control group), nerve conduits coated with hiPSC-derived neurospheres (iPS group), and autogenous nerve grafts (autograft group) (n = 8 per group). The survival of the iPSC-derived neurospheres was continuously tracked using in vivo imaging. At 12 weeks postoperatively, motor and sensory function and histological nerve regeneration were evaluated. Before implantation, the hiPSC-derived quaternary neurospheres that three-dimensional coated the nerve conduit were differentiated into Schwann-like cells. The transplanted hiPSC-derived neurospheres survived for at least 56 days after implantation. The iPS group showed non-significance higher sensory regeneration than the autograft group. Although there was no actual motor functional nerve regeneration in the three groups: control, iPS, and autograft groups, the motor function in the iPS group recovered significantly better than that in the control group, but it did not recover to the same level as that in the autograft group. Histologically, the iPS group demonstrated significantly higher axon numbers and areas, and lower G-ratio values than the control group, whereas the autograft group demonstrated the highest axon numbers and areas and the lowest G-ratio values. Nerve conduit three-dimensionally coated with hiPSC-derived neurospheres promoted axonal regeneration and functional recovery in repairing rat sciatic nerve small size defects. Transplantation of hiPSC-derived neurospheres with nerve conduits is a promising clinical iPSC-based cell therapy for the treatment of peripheral nerve defects.

Simultaneous Opposition Tendon Transfer with Median Nerve Decompression for Severe Bilateral Carpal Tunnel Syndrome in Adolescents with Hunter Syndrome: A Case Report.

Although carpal tunnel syndrome (CTS) is exceedingly rare in children, its prevalence in those with Hunter syndrome, mucopolysaccharidosis type II, is high. With the advent of hematopoietic stem cell transplantation and enzyme replacement therapy, the survival of patients with Hunter syndrome has dramatically improved. With improved longevity in these patients, CTS continues to progress with age. However, most patients with Hunter syndrome with CTS have generally been treated with an open carpal tunnel release (OCTR) only, without considering the severity. Here, we present a mid-term follow-up of a 16-year-old patient with Hunter syndrome associated with severe bilateral CTS successfully treated by the simultaneous opposition tendon transfer with an OCTR to improve the thumb function. Intraoperatively, the median nerve was constricted and flattened with congestion by the transverse carpal ligament. External and internal neurolysis of the scarred median nerve were performed and found epineural fibrosis and tethered epineurium. An intraneural lipoma of the left median nerve was especially resected with epineurotomy. During neurolysis and tendon transfer, the soft tissue was very viscous, a characteristic of mucopolysaccharidoses. Transferring the tension of the palmaris longus tendon to the abductor pollicis brevis for the thumb palmar abduction should be stronger than routine adult patients because the soft tissue such as the tendon excursion is stickier and more contracted in patients with Hunter syndrome. Postoperatively, a thumb spica splint was applied for 3 weeks, and then active motion exercises were cautiously started to prevent joint contracture. Early recognition and surgical intervention for CTS are essential in patients with Hunter syndrome.

Flexor tenosynovitis of the hand due to rare nontuberculous mycobacterium (Mycobacterium haemophilum) in an immunocompromised patient.

We report a case of purulent flexor tenosynovitis caused by Mycobacterium haemophilum in an immunosuppressed patient who received renal transplantation. Three synovial debridements and multiple antimicrobial administrations with clarithromycin, rifampicin, and moxifloxacin have been performed. No apparent recurrence has been observed two years after the final operation.

Traumatic index extensor tendon attenuation mimicking closed tendon rupture: two case reports.

BACKGROUND: While some traumatic closed index extensor tendon ruptures at the musclotendinous junction have been previously reported, closed index extensor tendon pseudorupture due to intertendinous attenuation is exceedingly rare with only one case report of a gymnastics-related sports injury in the English literature. Herein, we report two non-sports injury related cases of traumatic index extensor tendon attenuation mimicking closed tendon rupture, including the pathological findings and intraoperative video of the attenuated extensor indicis proprius tendon. CASE PRESENTATION: A 28-year-old man and a 30-year-old man caught their hands in a high-speed drill and lathe, respectively, which caused a sudden forced flexion of their wrists. They could not actively extend the metacarpophalangeal joints of their index fingers. Intraoperatively, although the extensor indicis proprius and index extensor digitorum communes tendons were in continuity without ruptures, both tendons were attenuated and stretched. The attenuated index extensor tendons were reconstructed either with shortening by plication or step-cut when the tendon damage was less severe or, in severely attenuated tendons, with tendon grafting (ipsilateral palmaris longus) or tendon transfer. Six months after the operation, the active extension of the index metacarpophalangeal joints had recovered well. CONCLUSIONS: Two cases of traumatic index extensor tendon attenuation were treated successfully by shortening the attenuated tendon in combination with tendon graft or transfer. We recommend WALANT (wide-awake local anesthesia and no tourniquet) in the reconstruction surgery of index extensor tendon attenuation to determine the appropriate amount of tendon shortening or optimal tension for tendon grafting or transfer. Intraoperative voluntary finger movement is essential, as it is otherwise difficult to judge the stretch length of intratendinous elongation and extent of traumatic intramuscular damage affecting tendon excursion.

A case series of seven patients with recurrent median nerve neuropathy treated by the revision surgery of median nerve neurolysis and wrapping with radial artery perforator adipose flap.

Adhesion neuropathy of the median nerve with persistent pain can be a challenging problem. Currently, coverage of the median nerve with a well-vascularized soft tissue is deemed necessary after secondary neurolysis. Herein, we reviewed the outcomes of seven patients with a persistent median nerve neuropathy after a primary open carpal tunnel release or a median nerve repair, treated with neurolysis and median nerve wrapping with radial artery perforator adipose flaps. During the revision surgery, after a careful and complete neurolysis of the scarred median nerve, the distally based radial artery perforator adipose flap without its fascia was raised and rotated to wrap the median nerve. The mean size of the perforator flap was 1146 mm2, which was enough to wrap the median nerve in all patients. At 26 months postsurgery, both the visual analog scale score for pain with tingling, and the patient-reported outcome measures improved. There was no recurrence of the median nerve adhesion neuropathy and no major complications were noted. Tinel's sign at the palmar wrist completely disappeared in four patients and was relieved in three patients. The median distal motor latency becomes recordable, and closer to a normal compound motor action potential postoperatively in all patients. Secondary neurolysis and median nerve wrapping with a radial artery perforator adipose flap, which was modified to be softer and thinner than the radial artery perforator adipofascial flap, was a successful treatment for the recurrent median nerve neuropathy in terms of both pain relief and restoration of the hand function.

Evaluation of dual release of stromal cell-derived factor-1 and basic fibroblast growth factor with nerve conduit for peripheral nerve regeneration: An experimental study in mice.

BACKGROUND: The development of drug delivery systems has enabled the release of multiple bioactive molecules. The efficacy of nerve conduits coated with dual controlled release of stromal cell-derived factor-1 (SDF-1) and basic fibroblast growth factor (bFGF) for peripheral nerve regeneration was investigated. MATERIALS AND METHODS: Sixty-two C57BL6 mice were used for peripheral nerve regeneration with a nerve conduit (inner diameter, 1 mm, and length, 7 mm) and an autograft. The mice were randomized into five groups based on the different repairs of nerve defects. In the group of repair with conduits alone (n = 9), a 5-mm sciatic nerve defect was repaired by the nerve conduit. In the group of repair with conduits coated with bFGF (n = 10), SDF-1 (n = 10), and SDF-1/bFGF (n = 10), it was repaired by the nerve conduit with bFGF gelatin, SDF-1 gelatin, and SDF-1/bFGF gelatin, respectively. In the group of repair with autografts (n = 10), it was repaired by the resected nerve itself. The functional recovery, nerve regeneration, angiogenesis, and TGF-ß1 gene expression were assessed. RESULTS: In the conduits coated with SDF-1/bFGF group, the mean sciatic functional index value (-88.68 ± 10.64, p = .034) and the axon number (218.8 ± 111.1, p = .049) were significantly higher than the conduit alone group, followed by the autograft group; in addition, numerous CD34-positive cells and micro vessels were observed. TGF-ß1 gene expression relative values in the conduits with SDF-1/bFGF group at 3 days (7.99 ± 5.14, p = .049) significantly increased more than the conduits alone group. CONCLUSION: Nerve conduits coated with dual controlled release of SDF-1 and bFGF promoted peripheral nerve regeneration.

Nerve capping with a nerve conduit for the treatment of painful neuroma in the rat sciatic nerve.

OBJECTIVE: Treatment of painful neuroma remains difficult, despite the availability of numerous surgical procedures. Recently, nerve capping treatment for painful neuroma using artificial nerve conduits has been introduced in clinical and basic research. However, the appropriate length of the nerve conduit and the pain relief mechanism have not been determined. In this study the authors aimed to investigate nerve capping treatment with a bioabsorbable nerve conduit using the rat sciatic nerve amputation model. Using histological analysis, the authors focused on the nerve conduit length and pain relief mechanism. METHODS: Sixteen Sprague Dawley rats were evaluated for neuropathic pain using an autotomy (self-amputation) score and gross and histological changes of the nerve stump 2, 4, 8, and 12 weeks after sciatic nerve neurectomy without capping. Forty-five rats were divided into 3 experimental groups, no capping (control; n = 15), capping with a 3-mm nerve conduit (n = 15), and capping with a 6-mm nerve conduit (n = 15). All rats were evaluated using an autotomy score and nerve stump histology 12 weeks after neurectomy. The nerve conduit was approximately 0.5 mm larger than the 1.5-mm diameter of the rat sciatic nerves to prevent nerve constriction. RESULTS: The autotomy scores gradually exacerbated with time. Without capping, a typical bulbous neuroma was formed due to random axonal regeneration 2 weeks after neurectomy. Subsequently, the adhesion surrounding the neuroma expanded over time for 12 weeks, and at the 12-week time point, the highest average autotomy scores were observed in the no-capping (control) group, followed by the 3- and the 6-mm nerve conduit groups. Histologically, the distal axonal fibers became thinner and terminated within the 6-mm nerve conduit, whereas they were elongated and protruded across the 3-mm nerve conduit. Minimal perineural scar formation was present around the terminated axonal fibers in the 6-mm nerve conduit group. Expressions of anti-α smooth muscle actin and anti-sigma-1 receptor antibodies in the nerve stump significantly decreased in the 6-mm nerve conduit group. CONCLUSIONS: In the rat sciatic nerve amputation model, nerve capping treatment with a bioabsorbable nerve conduit provided relief from neuroma-induced neuropathic pain and prevented perineural scar formation and neuroinflammation around the nerve stump. The appropriate nerve conduit length was determined to be more than 4 times the diameter of the original nerve.

Flexor pollicis longus tendon rupture by sandwiched underlying volar locking plate and distal radius.

Flexor pollicis longus (FPL) tendon rupture is a major complication of volar locking plate fixation for distal radius fractures. The tendon rupture is usually caused by friction between the distal edge of the plate and the FPL tendon, and has been well detected recently with ultrasonography. Rarely, the volar locking plate itself entraps the FPL tendon, leading to its rupture. A 63-year-old man was consistently unable to flex his right thumb after previous surgery for a distal radius fracture at another hospital. Ultrasonography demonstrated loss of tendon gliding and unusual patterns of the FPL tendon. The tendon was sandwiched between the plate and the distal radius, and was penetrated by the distal locking screw, which was comparable to intraoperative findings of complete entrapment and rupture of the FPL tendon from the underlying plate. The tendon defects were repaired using a palmaris longus tendon graft after removing the screws and plate. Finally, he could flex his thumb actively with satisfaction. Unusual patterns of FPL tendon rupture buried under inadequate plate positioning must be recognized, as in this case. Ultrasonographic assessment is routinely recommended to visibly determine any FPL tendon damage after volar locking plate fixation for distal radius fractures.

Protective effect of biodegradable nerve conduit against peripheral nerve adhesion after neurolysis.

OBJECTIVE Peripheral nerve adhesion caused by extraneural and intraneural scar formation after neurolysis leads to nerve dysfunction. The authors previously developed a novel very flexible biodegradable nerve conduit composed of poly(L-lactide) and poly(ε-caprolactone) for use in peripheral nerve regeneration. In the present study, they investigated the effect of protective nerve wrapping on preventing adhesion in a rat sciatic nerve adhesion model. METHODS Rat sciatic nerves were randomly assigned to one of the following four groups: a no-adhesion group, which involved neurolysis alone without an adhesion procedure; an adhesion group, in which the adhesion procedure was performed after neurolysis, but no treatment was subsequently administered; a nerve wrap group, in which the adhesion procedure was performed after neurolysis and protective nerve wrapping was then performed with the nerve conduit; and a hyaluronic acid (HA) group, in which the adhesion procedure was performed after neurolysis and nerve wrapping was then performed with a 1% sodium HA viscous solution. Six weeks postoperatively, the authors evaluated the extent of scar formation using adhesion scores and biomechanical and histological examinations and assessed nerve function with electrophysiological examination and gastrocnemius muscle weight measurement. RESULTS In the adhesion group, prominent scar tissue surrounded the nerve and strongly adhered to the nerve biomechanically and histologically. The motor nerve conduction velocity and gastrocnemius muscle weight were the lowest in this group. Conversely, the adhesion scores were significantly lower, motor nerve conduction velocity was significantly higher, and gastrocnemius muscle weight was significantly higher in the nerve wrap group than in the adhesion group. Additionally, the biomechanical breaking strength was significantly lower in the nerve wrap group than in the adhesion group and HA group. The morphological properties of axons in the nerve wrap group were preserved. Intraneural macrophage invasion, as assessed by the number of CD68- and CCR7-positive cells, was less severe in the nerve wrap group than in the adhesion group. CONCLUSIONS The nerve conduit prevented post-neurolysis peripheral nerves from developing adhesion and allowed them to maintain their nerve function because it effectively blocked scarring and prevented adhesion-related damage in the peripheral nerves.