Above-ground biomass references for urban trees from terrestrial laser scanning data.

BACKGROUND AND AIMS: Within extending urban areas, trees serve a multitude of functions (e.g. carbon storage, suppression of air pollution, mitigation of the 'heat island' effect, oxygen, shade and recreation). Many of these services are positively correlated with tree size and structure. The quantification of above-ground biomass (AGB) is of especial importance to assess its carbon storage potential. However, quantification of AGB is difficult and the allometries applied are often based on forest trees, which are subject to very different growing conditions, competition and form. In this article we highlight the potential of terrestrial laser scanning (TLS) techniques to extract highly detailed information on urban tree structure and AGB. METHODS: Fifty-five urban trees distributed over seven cities in Switzerland were measured using TLS and traditional forest inventory techniques before they were felled and weighed. Tree structure, volume and AGB from the TLS point clouds were extracted using quantitative structure modelling. TLS-derived AGB estimates were compared with AGB estimates based on forest tree allometries dependent on diameter at breast height only. The correlations of various tree metrics as AGB predictors were assessed. KEY RESULTS: Estimates of AGB derived by TLS showed good performance when compared with destructively harvested references, with an R2 of 0.954 (RMSE = 556 kg) compared with 0.837 (RMSE = 1159 kg) for allometrically derived AGB estimates. A correlation analysis showed that different TLS-derived wood volume estimates as well as trunk diameters and tree crown metrics show high correlation in describing total wood AGB, outperforming tree height. CONCLUSIONS: Wood volume estimates based on TLS show high potential to estimate tree AGB independent of tree species, size and form. This allows us to retrieve highly accurate non-destructive AGB estimates that could be used to establish new allometric equations without the need for extensive destructive harvesting.

Acquired Constriction Ring: A Case of Rubber Band Syndrome.

Rubber band syndrome is a rare entity seen in younger children mainly in communities where rubber bands are worn around the wrist for decorative purposes. When the band is worn for a long duration, it burrows through the skin and soft tissues resulting in distal edema, loss of function, and even damage to the neurovascular structures. These symptoms are difficult to relate to this rare but typical condition. We report a case of a 2¾-year-old girl with the history of a linear circumferential scar at the right wrist combined with the limited use of a swollen hand for several weeks. The child was taken to surgery with the purpose to release the red, indurated scar and eliminate the lymphatic congestion. A rubber band was found lying in a plane superficial to the flexor tendons but had cut through the superficial branch of the radial nerve and partially through the abductor pollicis longus tendon. The band was removed and the lacerated structures were repaired. The child had excellent recovery postoperatively. The cardinal features of a linear constricting scar around the wrist in the presence of a swollen hand should always alert the clinician to the possibility of a forgotten band around the wrist, which might have burrowed into the soft tissues for a period. Early recognition may be important to prevent further damage of essential structures.

Perilunate fracture-dislocations: clinical and radiological results of 21 cases.

BACKGROUND: Perilunate dislocations and fracture-dislocations are a subcategory of the carpal instability complex. Herein, we report our university hospital experience with this complex injury. The goal of our study was to find predictive factors and quantify the development of arthritis and lunate necrosis. We tried to measure the impact of arthritis on hand function. METHODS: Between January 2000 and December 2014, 21 patients underwent surgery for perilunate dislocations and perilunate fracture-dislocations of the wrist in our tertiary university center. Mean patient age was 29.3 ± 10.0 years (range 18-49 years). All displacements were posterior. They were reviewed both clinically and radiologically. RESULTS: Complications included misdiagnosed Essex-Lopresti-like lesion in one case, insufficient reposition of the carpus in two cases (LT in one case, SL in one case), and iatrogenic injury to the radial artery immediately sutured in one case. All 3 cases underwent a second procedure with satisfactory outcome. After a mean follow-up of 112 ± 60 months (range 12-210 months), the average Cooney score was 80 ± 19 (range 50-125). The mean PRWE score was 10 ± 8 (range 0-25). The mean DASH score was 40 ± 13 (range 30-75 months). Mean pain on load, measured with VAS was 1.1 ± 1.6; Clinical examination assessed a mean wrist extension/flexion of 42.4° ± 17.2°/48.4° ± 15.2°. Mean wrist ulnar/radial deviation was, respectively, 22.9° ± 11.3°/15.3° ± 7.0°. Mean pro/supination was, respectively, 75.2° ± 11.5°/76.3° ± 8.1°. Mean pinch strength was 9.4 ± 2.2 kg (87.4 ± 17.7% of the contralateral side). Mean power strength was 41.9 ± 9.9 kg (76.2 ± 19.2% of the contralateral side). Two patients had a scaphoid non-union identified on their most recent imaging. The mean carpal height ratio was 0.53 ± 0.05 (range 0.44-0.65). All except one patient developed arthritis: Grade 1 in 11 patients, Grade 2 in 3 patients, and Grade 3 in the remaining 6 patients. Age, length of follow-up, and loss of reduction were significantly associated with wrist arthritis (p < 0.001). Lunate avascular necrosis assessed by magnetic resonance imaging was present in 6 patients: Stage 2 in 4 patients, Stage 3a in 1 patient, and Stage 3b in the remaining patient. All these patients' intraoperative findings showed lesion of the cartilage of the radial side of the lunate. However, the small number of patients who developed lunate necrosis did not allow satisfactory statistical analysis. CONCLUSIONS: This retrospective study demonstrates good functional results despite the high rate of radiological wrist arthritis. Age, length of follow-up, and loss of reduction were significantly associated with wrist arthritis in our series.

The Role of Dynamic Ultrasound in the Immediate Conservative Treatment of Volar Plate Injuries of the PIP Joint: A Series of 78 Patients.

INTRODUCTION: The management of volar plate avulsion fractures in the context of a stable joint and a bony fragment of less than 30% has traditionally been conservative. This study was performed to assess volar plate healing with high-resolution ultrasound in order to provide early full mobilization. MATERIAL AND METHODS: Between January 2012 and December 2013, 78 patients with volar plate injuries of the proximal interphalangeal (PIP) joints (42 distortions and 36 dislocations) were treated conservatively in our department for volar plate avulsion fracture associated with stable joint and bony fragment inferior to 30% of the intra-articular surface assessed both by radiography and ultrasound. Conservative treatment included extension stop splinting for the first 2 weeks and Coban bandage until 6 weeks postinjury. However, it may be possible to modify the duration of extension stop splinting based on clinical and ultrasound findings (with no additional X-ray) performed every 2 weeks for the first 3 months and then at 4 months postinjury. Only patients with residual contracture at the 4-month assessment had prolonged follow-up in order to ensure adequate dynamic splint therapy. RESULTS: The amount of soft tissue oedema and the mobility of the volar plate were factors used to determine return to full mobilization. Mean extension-stop-splint wear was 16 ± 2 days. During the first 2 follow-up assessments, 4 patients were excluded from the study because of the instability of the PIP joint. One patient required refixation of a large fragment of 30%, 2 patients required superficial flexor tendon (FDS) tenodesis of the unstable volar plate in hyperextension and 1 other patient required arthrodesis of the PIP joint. In 51 patients, the postoperative follow-up was free of complications at 4 months. In 18 patients, flexion contracture of 20° (range 11°-40°) and oedema during follow-up required dynamic extension splints for 3 to 5 months. After this time, 5 patients had a residual contracture of 10° to 15°. CONCLUSION: Avulsion fractures of the volar plate at the PIP joint are common. In general, they have a good outcome using the conservative treatment with extension block splints. Flexion contracture is a common complication and may be reduced by immediate splints in full extension at night and Coban bandage during the day. High-resolution sonography is a convenient tool to evaluate palmar plate stability, to assess reduction of oedema, and thus to guide safe return to full range of movement.

INTRODUCTION: La prise en charge des avulsions de la plaque palmaire lorsque l'articulation est stable et que le fragment osseux est inférieur à 30 % est habituellement conservative. Cette étude visait à évaluer la cicatrisation de la plaque palmaire à l'aide de l'échographie à haute resolution afin de favoriser un retour rapide à une mobilisation complète. MATÉRIEL ET MÉTHODES: Entre janvier 2012 et décembre 2013, 78 patients ayant des lésions de la plaque palmaire des articulations interphalangiennes proximales (IPP) (42 distorsions, 36 dislocations) associées à une articulation stable et à un fragment osseux inferieur à 30 % de la surface articulaire à la radiographie ont été traité de manière conservative et suivi par échographie. Le traitement incluait une attelle extension-stop pendant les deux premières semaines, puis un bandage CobanMD pendant les quatre semaines suivantes. Il était cependant possible d'adapter la durée du port de l'attelle en fonction des données cliniques et de l'échographie (sans radiographie) réalisée toutes les 2 semaines jusqu'à 3 mois, puis le quatrième mois suivant la lésion. Seuls les patients présentant une contracture résiduelle au bout de quatre mois étaient soumis à un suivi prolongé incluant une attelle dynamique. RÉSULTATS: L'ampleur de l'œdème des tissus mous et la mobilité de la plaque palmaire faisaient partie des facteurs utilisés pour déterminer le retour à une mobilisation complète. Le port moyen de l'attelle extension-stop était de 16±2 jours. Lors des deux premières évaluations de suivi, quatre patients furent exclus de l'étude en raison de l'instabilité de l'articulation IPP : Pour un patient, un fragment de 30% a nécessité une refixation, pour deux patients, une ténodèse du tendon fléchisseur superficiel (TFS) a permis de stabiliser l'articulation instable en hyperextension et pour le dernier patient, une arthrodèse de l'IPP fut réalisée. Chez 51 patients, la guérison était complète après 4 mois. Chez 18 patients, une contracture résiduelle de 20° de flexion (11° à 40°) a exigé le port d'une attelle dynamique d'extension pendant une durée complémentaire de 3 à 5 mois. Après cette periode, cinq patients présentaient une contracture residuelle de 10° à 15°. CONCLUSION: Les avulsions de la plaque palmaire de l'articulation IPP sont des lésions courantes. Habituellement, un traitement conservateur à l'aide d'une attelle extension-stop permet leur guérison rapide. L'echographie à haute résolution quantifie la réduction de l'œdème et la guérision de la plaque palmaire, et par là permet de limiter le port de cette attelle extension-stop. La contracture résiduelle en flexion est une complication courante qui peut être traitée par attelle dynamique.

Nerve Transfers for Persistent Traumatic Peroneal Nerve Palsy: The Inselspital Bern Experience.

BACKGROUND: Patients in whom conventional peroneal nerve repair surgery failed to reconstitute useful foot lift need to be evaluated for their suitability to undergo a concomitant tendon transfer procedure or nerve transfers. OBJECTIVE: To report our first clinical experience with nerve transfers for persistent traumatic peroneal nerve palsy. METHODS: Between 2007 and 2013, 8 patients were operated on for foot drop after unsuccessful nerve surgery. Six patients without fatty degeneration of the anterior tibial muscle and proximal lesion of the peroneal nerve were oriented for tibial to peroneal nerve transfer. In the other 2 cases where the anterior and lateral compartments were destructed, the anterior tibial muscle function was reconstructed with a neurotized lateral gastrocnemius transfer. For each patient, we graded postoperative results using the British Medical Research Council scheme and the Ninkovic assessment scale. RESULTS: Of the 6 patients who underwent nerve transfer of the anterior tibial muscle, 2 patients had excellent results, 1 patient had good results, 1 patient had fair results, and 2 patients had poor results. Of the 2 patients that underwent neurotized lateral gastrocnemius transfer, 1 patient achieved excellent results after tenolysis, whereas 1 patient achieved poor results. After the nerve transfer, 5 patients did not wear an ankle-foot orthosis. Four patients did not limp. Four patients were able to walk barefoot, navigate stairs, and participate in activities. CONCLUSION: Early clinical results after tibial to peroneal nerve transfer and neurotized lateral gastrocnemius transfer appear mixed. The results of nerve transfer seem, on the whole, less reliable than the literature reports on tendon transfer.

Endoscopically assisted nerve decompression of rare nerve compression syndromes at the upper extremity.

BACKGROUND: Besides carpal tunnel and cubital tunnel syndrome, other nerve compression or constriction syndromes exist at the upper extremity. This study was performed to evaluate and summarize our initial experience with endoscopically assisted decompression. MATERIALS AND METHODS: Between January 2011 and March 2012, six patients were endoscopically operated for rare compression or hour-glass-like constriction syndrome. This included eight decompressions: four proximal radial nerve decompressions, and two combined proximal median nerve and anterior interosseus nerve decompressions. Surgical technique and functional outcomes are presented. RESULTS: There were no intraoperative complications in the series. Endoscopy allowed both identifying and removing all the compressive structures. In one case, the proximal radial neuropathy developed for 10 years without therapy and a massive hour-glass nerve constriction was observed intraoperatively which led us to perform a concurrent complementary tendon transfer to improve fingers and thumb extension. Excellent results were achieved according to the modified Roles and Maudsley classification in five out of six cases. All but one patient considered the results excellent. The poorest responder developed a CRPS II and refused post-operative physiotherapy. CONCLUSION: Endoscopically assisted decompression in rare compression syndrome of the upper extremity is highly appreciated by patients and provides excellent functional results. This minimally invasive surgical technique will likely be further described in future clinical studies.

Anatomic study of the superficial sural artery and its implication in the neurocutaneous vascularized sural nerve free flap.

Combined extended nerve and soft tissue defects of the upper extremity require nerve reconstruction and adequate soft tissue coverage. This study focuses on the reliability of the free vascularized sural nerve graft combined with a fasciocutaneous posterior calf flap within this indication. An anatomical study was performed on 26 cadaveric lower extremities that had been Thiel fixated and color silicone injected. Dissection of the fasciocutaneous posterior calf flap involved the medial sural nerve and superficial sural artery (SSA) with its septocutaneous perforators, extended laterally to include the lateral cutaneous branch of the sural nerve and continued to the popliteal origin of the vascular pedicle and the nerves. The vessel and nerves diameter were measured with an eyepiece reticle at 4.5× magnification. Length and diameter of the nerves and vessels were carefully assessed and reported in the dissection book. A total of 26 flaps were dissected. The SSA originated from the medial sural artery (13 cases), the popliteal artery (12 cases), or the lateral sural artery (one case). The average size of the SSA was 1.4 ± 0.4 mm. The mean pedicle length before the artery joined the sural nerve was 4.5 ± 1.9 cm. A comitant vein was present in 21 cases with an average diameter of 2.0 ± 0.8 mm, in 5 cases a separate vein needed to be dissected with an average diameter of 3.5 ± 0.4 mm. The mean medial vascularized sural nerve length was 21.2 ± 8.9 cm. Because of inclusion of the vascularized part of the lateral branch of the sural nerve (mean length of 16.7 ± 4.8 cm), a total of 35.0 ± 9.6 cm mean length of vascularized nerve could be gained from each extremity. The free vascularized sural nerve graft combined with a fasciocutaneous posterior calf flap pedicled on the SSA offers a reliable solution for complex tissue and nerve defect.

Macroreplantations of the upper extremity: a series of 11 patients.

INTRODUCTION: Micro- or macroreplantation is classified depending on the level of amputation, distal or proximal to the wrist. This study was performed to review our experience in macroreplantation of the upper extremity with special attention to technical considerations and outcomes. MATERIALS AND METHODS: Between January 1990 and December 2010, 11 patients with a complete amputation of the upper extremity proximal to the wrist were referred for replantations to our department. The patients, one woman and ten men, had a mean age of 43.4 ± 18.2 years (range 19-76 years). There were two elbow, two proximal forearm, four mid-forearm, and three distal forearm amputations. The mechanism of injury was crush in four, crush-avulsion in five and guillotine amputation in two patients. The Chen classification was used to assess the postoperative outcomes. The mean follow-up after macroreplantation was 7.5 ± 6.3 years (range 2-21 years). RESULTS: All but one were successfully replanted and regained limb function: Chen I in four cases (36 %), Chen II in three cases (27 %), Chen III in two cases (18 %), and Chen IV in one patient (9 %). We discuss the steps of the macroreplantation technique, the need to minimize ischemic time and the risk of ischemia reperfusion injuries. CONCLUSION: Thanks to improvements in technique, the indications for limb preservation after amputation can be expanded. However, because of their rarity, replantations should be performed at specialist replantation centers. LEVEL OF EVIDENCE: Level IV.