Scapular Elevation Sign - A New Sign in Evaluation of Thoracic Outlet Syndrome.

Background: We noted that patients with thoracic outlet syndrome (TOS) have elevation of the ipsilateral scapula and named this the scapular elevation sign (SES). The aim was to determine the prevalence of SES in a normal cohort, compare SES with other provocative tests and to determine the treatment effect on SES. Methods: First, normal asymptomatic subjects were prospectively assessed to determine the prevalence of SES in a normal cohort. Second, patients with TOS were retrospectively examined for the presence of SES and four provocative tests: supraclavicular pressure, scalene test, elevated arm stress test (EAST) and the military brace manoeuvre. All patients were initially treated non-surgically. Surgery was offered to patients with persistent symptoms at 6 months. Patients were re-examined for the presence of the SES after treatment. Results: The prevalence of SES in our normal cohort was 4% (2/53). Our study cohort included 20 patients with TOS. The SES was positive in 18 patients (90%). Supraclavicular pressure was positive in 11 (55%), scalene test in 13 (65%), EAST in 9 (45%) and military brace manoeuvre in 11 patients (55%). Following non-surgical treatment, six patients had symptom resolution, three had improvement, nine persistent symptoms and two were lost to follow-up. The SES was positive in one out of six patients with symptom resolution, two out of three patients with improvement and in all nine patients with persistent symptoms. Patients with persistent symptoms underwent surgery with symptom resolution in eight and improvement in one patient. The SES remained positive in two patients after surgical treatment. Conclusions: The SES is simple and sensitive, does not rely on variations in performance of the test and suitable for diagnosis and assessment of outcomes of TOS. Level of Evidence: Level III (Diagnostic).

Updates in peripheral nerve surgery of the upper extremity: diagnosis and treatment options.

The loss of function resulting from peripheral nerve injuries confers a significant burden to the patient and society. The treatment of peripheral nerve injuries requires an accurate diagnosis and formulation of a functional reconstructive plan. Advances in peripheral nerve imaging complement electrodiagnostic studies, and provide us with detailed information regarding the status of nerve injury, repair, and regeneration in order to prognosticate recovery and determine the need for surgical intervention. When direct nerve repair is not possible, the methods for bridging a nerve gap are the nerve autograft, allograft and conduit. While current research supports the use of conduits and nerve allografts for shorter nerve gaps, the nerve autograft still remains the gold standard for bridging a nerve gap. When direct nerve repair or nerve grafting fails, or is anticipated to be insufficient, nerve transfers are an alternative for reconstruction. Knowledge of axonal counts, upper limb innervation patterns, location and clustering of upper limb peripheral nerves allows for the design of new nerve transfers. The options of nerve transfers for radial, ulnar and median nerve injuries are outlined, as well as their outcomes. Nerve transfers are an attractive option for restoring motor and sensory function while minimizing donor site morbidity. However, one must consider their limitations, and preserve donor sites for secondary tendon transfer options. This article presents the latest information regarding the imaging of peripheral nerves, methods to bridge a nerve gap, and nerve transfers to aid the peripheral nerve surgeon in choosing a reconstructive plan.

Upper Extremity Axon Counts and Clinical Implications for Motor Nerve Transfer.

BACKGROUND: Nerve transfers are planned based on the following parameters: location, number of branches, and axon count matching of the donor and recipient nerves. The authors have previously defined the former two in upper limb muscles. In the literature, axon counts are obtained from various sources, using different methods of histomorphometry. This study describes the axon counts of the same primary motor nerve branches from the authors' previous study using a uniform method of manual histomorphometry and completes the authors' blueprint of upper limb neuromuscular anatomy for reconstructive surgery. METHODS: The distal ends of the primary nerve branches of 23 upper limb muscles were harvested from 10 fresh frozen cadaveric upper limbs. Manual quantitative histomorphometry was performed by two independent investigators, and the average was reported. RESULTS: The primary nerve branches of the arm muscles had higher average axon counts (range, 882 to 1835) compared with those of the forearm muscles (range, 267 to 883). In the forearm, wrist flexor (range, 659 to 746) and extensor (range, 543 to 745) nerve branches had axons counts that were similar to those of potential donors (e.g., supinator, n = 602; pronator teres, n = 625; flexor digitorum superficialis, n = 883; and flexor digitorum profundus, n = 832). CONCLUSIONS: Apart from describing the axon counts of the upper limb, the authors have found that the forearm axon counts are very comparable. This insight, when combined with information on the location and number of primary nerve branches, will empower surgeons to tailor bespoke nerve transfers for every clinical situation.

Nerve Compression in the Upper Limb.

Nerve compression occurs in fibro-osseous tunnels as the nerves cross joints. The pathology involves traction and adhesion, aside from compression. This can occur at multiple sites along the course of the nerve. Regardless of level, clinical assessment is standard and a systematic approach to uncover all sites of compression is advised. Evolution of management for carpal tunnel and cubital tunnel syndrome is reviewed with an emphasis on natural history and nonsurgical treatment, which are not commonly discussed. Treatment is multimodal and the systemic factors that contribute to nerve dysfunction should also be addressed.

Structural Adaptations of the Primate Flexor Carpi Ulnaris After Tendon Transfer.

PURPOSE: Muscle remodeling occurs after tendon transfer. However, it is not known whether these adaptations are permanent and clinically significant. This study examined the early and late structural adaptations following a standard tendon transfer in a primate model. METHODS: A flexor carpi ulnaris (FCU) to extensor digitorum communis (EDC) transfer was performed in 8 adult monkeys. A sham operation was performed in the contralateral forearm. Four animals were sacrificed at 5 months (early cohort) and 4 at 16 months (late cohort). The transferred FCU, contralateral FCU, and EDC muscles were removed for analysis. Fiber length (FL), physiological cross-sectional area (PCSA), and gross morphology of the transferred FCU were compared with the contralateral EDC and FCU. RESULTS: In the early cohort, the FL of the transferred FCU was longer than the control FCU and similar to the contralateral EDC. The PCSA of the transferred FCU was lower than that of the control FCU but greater than the control EDC. In the late cohort, the difference in FL and PCSA between the transferred FCU and the control FCU persisted. The PCSA of the transferred FCU was similar to that of the control EDC. The bipennate transferred FCU had also undergone gross morphological changes to resemble the multipennate EDC. CONCLUSIONS: This study demonstrates, in a primate model, that the FCU undergoes structural adaptations to resemble the EDC following an FCU-to-EDC transfer. However, these adaptations are incomplete and not sustained over time. CLINICAL RELEVANCE: This study demonstrates that there is muscle plasticity in tendon transfers in a primate model. However, it is important to match potential donor muscles to the recipient during tendon transfer.

Impact of inpatient Care in Emergency Department on outcomes: a quasi-experimental cohort study.

BACKGROUND: Hospitals around the world are faced with the issue of boarders in emergency department (ED), patients marked for admission but with no available inpatient bed. Boarder status is known to be associated with delayed inpatient care and suboptimal outcomes. A new care delivery system was developed in our institution where boarders received full inpatient care from a designated medical team, acute medical team (AMT), while still residing at ED. The current study examines the impact of this AMT intervention on patient outcomes. METHODS: We conducted a retrospective quasi-experimental cohort study to analyze outcomes between the AMT intervention and conventional care in a 1250-bed acute care tertiary academic hospital in Singapore. Study participants included patients who received care from the AMT, a matched cohort of patients admitted directly to inpatient wards (non-AMT) and a sample of patients prior to the intervention (pre-AMT group). Primary outcomes were length of hospital stay (LOS), early discharges (within 24 h) and bed placement. Secondary outcomes included unplanned readmissions within 3 months, and patient's bill size. χ2- and Mann-Whitney U tests were used to test for differences between the cohorts on dichotomous and continuous variables respectively. RESULTS: The sample comprised of 2279 patients (1092 in AMT, 1027 in non-AMT, and 160 in pre-AMT groups). Higher rates of early discharge (without significant differences in the readmission rates) and shorter LOS were noted for the AMT patients. They were also more likely to be admitted into a ward allocated to their discipline and had lower bill size compared to non AMT patients. CONCLUSIONS: The AMT intervention improved patient outcomes and resource utilization. This model was noted to be sustainable and provides a potential solution for hospitals' ED boarders who face a gap in inpatient care during their crucial first few hours of admissions while waiting for an inpatient bed.

Upper Extremity Innervation Patterns and Clinical Implications for Nerve and Tendon Transfer.

BACKGROUND: The authors previously studied the intramuscular innervation of 150 upper limb muscles and demonstrated that certain patterns of intramuscular innervation allowed muscles to be split into compartments with independent function. This study aims to determine the location, extramuscular course, and number of motor nerve branches of upper limb peripheral nerves. The authors want to combine this information with their previous work to create a blueprint of upper limb neuromuscular anatomy that would be useful in reconstructive surgery. METHODS: Ten fresh frozen cadaveric upper limbs were dissected. The origin of branches from the peripheral nerve trunk, their course, and the number of motor nerves per muscle were determined. The authors reviewed all the images of the Sihler-stained muscles from their earlier study. RESULTS: Motor nerve branches arise at the intersection of nerve trunk and muscle belly and are clustered near the origin of muscle groups. Two patterns of extramuscular innervation were noted, with one group having a single motor nerve and another group with consistently more than one motor nerve. A modified classification of muscles was proposed based on the orientation of muscle fibers to the long axis of the limb, the number of muscle compartments, and the number of heads of origin or the tendons of insertion. CONCLUSIONS: Motor nerve clusters can be located based on fixed anatomical landmarks. Muscles with multiple motor nerves have morphology that allows them to be split into individual compartments. The authors created a muscle and nerve blueprint that helps in planning nerve and split muscle transfers.

The value of the tender muscle sign in detecting motor recovery after peripheral nerve reconstruction.

PURPOSE: Squeezing a denervated muscle a few weeks after nerve repair produces a characteristic response in patients. This response is observed before any clinical evidence of motor recovery. We called this response the tender muscle sign (TMS) and wanted to determine whether this sign was related to the recovery of motor power. METHODS: We studied 31 adults with unilateral brachial plexus injuries who underwent 50 procedures for reinnervation of the supraspinatus, deltoid, and biceps. Follow-up was monthly for the first year and at 3-monthly intervals thereafter. Average duration of follow-up was 3.3 years. The TMS was sought at each visit. The presence of the TMS, when it was first observed, and time to Medical Research Council (MRC) grade 1 and 3 recoveries were recorded. The sensitivity, specificity, and predictive values of TMS for motor recovery were calculated. RESULTS: The TMS was always detected earlier than palpable muscle contraction. It was significantly associated with recovery of MRC grade 1 and 3 motor power. The sensitivity of TMS for MRC grade 1 recovery was 96% and specificity was 100%. For MRC grade 3 recovery, it had 97% sensitivity and 27% specificity. The positive predictive value was 100% for MRC grade 1 recovery and 83% for MRC grade 3. The negative predictive value was 50% for MRC grade 1 recovery and 75% for MRC grade 3. CONCLUSIONS: Previous studies have demonstrated the presence of nocioceptive receptors in human skeletal muscle. The reinnervation of these receptors by the regenerating axons results in cramp-like tenderness when the muscle is squeezed. This response is specific to a reinnervated muscle and cannot be elicited in denervated or normally innervated muscle. The TMS is a simple, clear, and early indicator of muscle reinnervation that is useful in monitoring motor recovery after nerve regeneration. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

Biomechanical comparison of different suturing techniques in rabbit medial gastrocnemius muscle laceration repair.

INTRODUCTION: Skeletal muscle laceration is a common injury. Repair of disrupted delicate tissue is still a clinical challenge for surgeons. A few different muscle repair techniques have been reported. However, the best muscle repair technique has not been identified. The aim of the present study is to compare the biomechanical features of different repair techniques in muscles to identify the most effective one. MATERIAL AND METHODS: New Zealand white rabbits (2.5-3 kg) were euthanized and medial gastrocnemius muscles were isolated. The muscles were completely transected with scalpels and then repaired by 3 different techniques, namely, (1) 2-strand mattress, (2) 4-strand Kessler (with epitendinous suture), and (3) Mason-Allen. To measure suture performance, the repaired specimens were mounted onto a mechanical testing machine Instron 5543. The muscles were loaded to failure at a constant speed of 60 mm/min. Data collected from Merlin v5.31 software were used to compute the biomechanical properties of each specimen. RESULTS: There was no significant difference in the mean maximum load of Kessler group (15.5 N) and Mason-Allen group (13.2 N), whereas the mean maximum load of the control (Mattress) group (4.4 N) was significantly smaller than the other 2 groups. Moreover, Kessler stitches were the stiffest among the 3. It is noteworthy that the mechanisms of failure were different: Kessler stitches were all pulled out longitudinally, whereas Mason-Allen stitches transmitted load across the laceration and ruptures occur at areas adjacent to the stitches, indicating that muscle is the weakest element in the biomechanical testing. CONCLUSIONS: Both Kessler and Mason-Allen stitches have shown better biomechanical features compared with the control group. Further study has to be done to compare the effect of these 2 techniques on muscle regeneration and scar formation in an in vivo model.

The dorsal metatarsal artery perforator flap.

Few options exist for the resurfacing of web-space and small soft tissue defects of the dorsum of the distal foot. The study examines the anatomy of the second to fourth dorsal metatarsal arteries in 16 fresh frozen cadavers to determine if the anatomy correlates to that in the hand, permitting the design of local flaps based on perforators of these vessels. A clinical case is also presented, illustrating the efficacy of such a perforator-based flap.Sixteen Asian cadaveric lower limbs were used for this study. The specimens were prepared with latex dye injection. Dissection under loupe magnification was carried out to determine the position and caliber of the cutaneous perforators from the dorsal metatarsal arteries, and the spread of the latex dye in the skin from these cutaneous perforators. One clinical case illustration of this perforator-based flap for distal foot defect resurfacing is presented.In our cadaveric study, each second to fourth dorsal metatarsal artery had between 2 and 5 cutaneous perforators with calibers of 0.5 to 0.7 mm in diameter. The most distal cutaneous perforator was present consistently, always arising between the heads of the respective metatarsals.In conclusion, the vascular anatomy of the second to fourth dorsal metatarsal arteries is similar to that in the hand, thus allowing for the design of reliable perforator-based flaps for distal foot resurfacing.

The effect of fibrin glue on tendon healing and adhesion formation in a rabbit model of flexor tendon injury and repair.

Fibrin glue has been widely used in a variety of surgical procedures to promote haemostasis and tissue bonding. It can also be used as a cell carrier for stem cells on tendons. However, the data about the effect of fibrin glue on flexor tendon healing is very limited. The present study examined the role of fibrin glue TISSEEL® in a rabbit model of flexor tendon injury. The rabbits were killed 3 or 8 weeks after the operation. The range-of-motion of the fingers and biomechanical properties of tendons were measured and compared between the control group and TISSEEL-treated group. The findings have shown that the range-of-motion in the TISSEEL-treated group was significantly different from that of the control group at 3 weeks after the operation. However, there is no significant difference in range-of-motion at 8 weeks after the operation. Moreover, there is no significant difference in biomechanical properties between the control group and TISSEEL-treated group. The results indicate that TISSEEL may attenuate adhesion formation at the early stage of flexor tendon repair. However, there is no significant effect on biomechanical features during tendon repair. In conclusion, this study has shown that it may be safe to use TISSEEL in tissue engineering applications for tendon regeneration and healing.

Supraorbital nerve conduction study in normal subjects.

There is currently no examination technique that allows direct measurement of supraorbital nerve conduction velocity and amplitude. Therefore, in this study we describe a novel nerve conduction technique that allows measurement of the supraorbital sensory nerve action potential (SNAP) distal to the supraorbital foramen. Supraorbital SNAPs were recorded bilaterally from 17 healthy volunteers using an antidromic technique. The SNAPs were consistently recordable over the site 6 cm lateral to the midline point that was marked 10 cm above the nasion. Measured parameters included peak latency (mean 2.3 ms, SD 0.3), amplitude (mean 14.6 µV; SD 10.5), and velocity (mean 51.3 m/s, SD 6.8). The mean percentage of interside difference in amplitude was 25.6% (SD 17.3). Cut-off values (97th percentile) were 2.7 ms (peak latency), 3.3 µV (amplitude), 41.9 m/s (conduction velocity), and 54.9% (interside difference in amplitude). Supraorbital SNAPs can be recorded in all normal subjects and used as a quantitative measure of the functioning large fibers in the nerve.

Application of the dorsal metacarpal artery perforator flap for resurfacing soft-tissue defects proximal to the fingertip.

BACKGROUND: The dorsal metacarpal artery perforator flap is a versatile solution for resurfacing soft-tissue defects of fingers. The authors present their experience in applying this flap for a variety of finger wounds for which conventional means may not be amenable. METHODS: Fifty-eight dorsal metacarpal artery perforator flaps were used to resurface 60 finger soft-tissue defects in 56 patients over a 5-year period. Fifty-two patients were men and their average age was 37 years. This flap was used to reconstruct soft-tissue defects after débridement of infected wounds in 28 patients, traumatic wounds in 26 patients, and electrical burns in two patients. RESULTS: The average flap size was 4.6 × 2.3 cm; 34 flaps were based on the second dorsal metacarpal artery perforator, 14 were based on the third dorsal metacarpal artery perforator, and 10 were based on the fourth dorsal metacarpal artery perforator. Twenty-one flaps were used to resurface defects distal to the proximal interphalangeal joint, and 37 flaps were used to resurface defects over the proximal interphalangeal joint and proximal to it. Skin grafting was needed to close the donor defect in seven patients. Complications included venous congestion in six flaps and arterial insufficiency in three flaps, with total loss of two flaps and infection in one case. CONCLUSION: The dorsal metacarpal artery perforator flap is a thin, pliable flap that is simple to raise, has minimal donor-site morbidity, and can reliably cover soft-tissue defects up to the proximal half of the middle phalanx. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Dermal pocketing following distal finger replantation.

Replantation is an ideal technique for reconstruction following fingertip amputation as it provides 'like for like' total reconstruction of the nail complex, bone pulp tissue and skin with no donor-site morbidity. However, fingertips are often not replanted because veins cannot be found or are thought to be too small to repair. Attempts at 'cap-plasty' or pocketing of replanted tips with and without microvascular anastomosis have been done in the past with varying degrees of success. We prospectively followed up a group of patients who underwent digital replantation and dermal pocketing in the palm to evaluate the outcome of this procedure. There were 10 patients with 14 amputated digits (two thumbs, five index, four middle, two ring and one little) who underwent dermal pocketing of the amputated digit following replantation. Among the 14 digits that were treated with dermal pocketing, 11 survived completely, one had partial atrophy and two were completely lost. Complications encountered included finger stiffness (two patients) and infection of the replanted fingertip with osteomyelitis of the distal phalanx (one patient). We believe that this technique can help increase the chance of survival for distal replantation with an acceptable salvage rate of 85% in our series.

A novel rabbit model for the evaluation of retrograde flow venous flaps.

Venous flaps have several potential advantages over traditional flaps, but their uses have been limited by unpredictable survival. Although clinical and experimental studies have concentrated mainly on the antegrade arterialization of venous flaps to increase survival, retrogradely arterialized venous flaps (AVFs) may have the greatest potential. There is, however, little literature on their use. There are also no animal studies comparing their survival to other venous flaps used in a similar situation. Our aim was to design a flap utilizing the rabbit's valved, thoracoepigastric vein (consisting of the lateral thoracic and epigastric veins) as the source vessel for the study of retrograde arterialized venous flaps (RAVFs). A pilot study (n = 10) to determine the survival of RAVFs was performed utilizing this animal model. Four flaps had complete survival at the end of our 2-week observational period. However, we also had four partial flap losses and two cases in which the entire flap was lost. An average survival area of 44.5% was observed. In conclusion, our designed rabbit thoracoepigastric RAVF is simple to apply and easily reproducible. It is the first animal flap adapted specifically for the study of RAVFs, and may be used for the further investigation of these flaps, which have shown unpredictable survival to date.

Bone marrow-derived mesenchymal stem cells influence early tendon-healing in a rabbit achilles tendon model.

BACKGROUND: A repaired tendon needs to be protected for weeks until it has accrued enough strength to handle physiological loads. Tissue-engineering techniques have shown promise in the treatment of tendon and ligament defects. The present study tested the hypothesis that bone marrow-derived mesenchymal stem cells can accelerate tendon-healing after primary repair of a tendon injury in a rabbit model. METHODS: Fifty-seven New Zealand White rabbits were used as the experimental animals, and seven others were used as the source of bone marrow-derived mesenchymal stem cells. The injury model was a sharp complete transection through the midsubstance of the Achilles tendon. The transected tendon was immediately repaired with use of a modified Kessler suture and a running epitendinous suture. Both limbs were used, and each side was randomized to receive either bone marrow-derived mesenchymal stem cells in a fibrin carrier or fibrin carrier alone (control). Postoperatively, the rabbits were not immobilized. Specimens were harvested at one, three, six, and twelve weeks for analysis, which included evaluation of gross morphology (sixty-two specimens), cell tracing (twelve specimens), histological assessment (forty specimens), immunohistochemistry studies (thirty specimens), morphometric analysis (forty specimens), and mechanical testing (sixty-two specimens). RESULTS: There were no differences between the two groups with regard to the gross morphology of the tendons. The fibrin had degraded by three weeks. Cell tracing showed that labeled bone marrow-derived mesenchymal stem cells remained viable and present in the intratendinous region for at least six weeks, becoming more diffuse at later time-periods. At three weeks, collagen fibers appeared more organized and there were better morphometric nuclear parameters in the treatment group (p < 0.05). At six and twelve weeks, there were no differences between the groups with regard to morphometric nuclear parameters. Biomechanical testing showed improved modulus in the treatment group as compared with the control group at three weeks (p < 0.05) but not at subsequent time-periods. CONCLUSIONS: Intratendinous cell therapy with bone marrow-derived mesenchymal stem cells following primary tendon repair can improve histological and biomechanical parameters in the early stages of tendon-healing.