Synthetic exposure with a CMOS camera for multiple exposure speckle imaging of blood flow.

Speckle contrast imaging is an established technique to obtain relative blood flow maps over wide fields of view. A major improvement of the method relies on the acquisition of raw speckle images at different exposure times but requires simultaneous modulation of a laser pulse in duration and intensity and precise synchronization with a camera. This complex instrumentation has limited the use of multiple exposure speckle imaging. We evaluate here the use of a CMOS camera for a simplified approach based on synthetic exposure images created from the sum of successive frames acquired at a 1 ms exposure time. Both methods have been applied to evaluate controlled flows in micro-channels. The contribution of noises to the speckle contrast have been quantified and compared. Dark, readout and shot noise contributions to the total contrast remain constant for modulated exposure, while all these contributions decrease with increasing exposure time for synthetic exposure. The relative contribution of noises to speckle contrast depends on the level of illumination and the exposure time. Guidelines for flow measurements and limitations of the use of a CMOS camera with a limited frame rate for synthetic exposure acquisition scheme are discussed. The synthetic exposure method is simple to implement and should facilitate the translation of multiple exposure speckle imaging to clinical set-ups.

Palsy of elbow extension.

Elbow extension palsy is generally well tolerated, because when standing up, it is alleviated by gravity. In the case of trunk paralysis or brachial plexus palsy, standing is possible, thus the restoration of active elbow extension improves the hand's positioning above the shoulder, and allows the elbow to be locked in extension, which is necessary during certain activities such as cycling. In these palsy cases, the triceps brachii will be reinnervated by nerve transfers if surgery is performed early enough before irreversible atrophy of the effector muscle sets in. In these situations, secondary tendon transfers are rarely indicated. Few available muscles can be harvested without deleterious consequences on the donor site. Finally, in patients with a very deficient upper limb but with a healthy contralateral limb, when nerve transfers are no longer possible, elbow extension will not be restored. In the tetraplegics using a wheelchair, elbow extension becomes essential for positioning the hand in space and for potentiating the transferable muscles to activate the hand. As nerve transfers have rare indications and are currently being validated in this population, palliative tendon transfers are the reference technique. They must be integrated into an overall upper limb reconstructive surgery program that takes into consideration the potentially usable muscles and the presence of elbow flexion contracture and supination deformity of the forearm. Elbow extension restoration techniques are based on the transfer of two muscles, the posterior deltoid and the biceps brachii. The first is very effective and has very specific requirements, notably good anterior stabilization of the shoulder by the pectoralis major, while the second has broader indications, notably in the case of elbow contracture and inability to stabilize the shoulder anteriorly.

Wrist shortening arthrodesis with volar plate in a dorsal position for spastic wrist contracture.

Total wrist arthrodesis in severe wrist flexion deformities (greater than 60°) due to spasticity represents a valid therapeutic option. It aims to improve the hand's appearance, hygiene, function and to prevent the deformity from getting worse. The objective of this study is to evaluate the clinical and anatomical results of wrist shortening arthrodesis using a classic volar plate in the dorsal position in functional surgery for central spastic hands. We conducted a single-center analysis of a series of patients who underwent this shortening arthrodesis. The review at a minimum 1-year follow-up included a clinical evaluation (House score, INOM score, patient satisfaction and complications), and anatomical evaluation (arthrodesis position, bone healing and carpometacarpal arthropathy). Twenty-eight patients with a mean age of 40.6 years (18-74) were included at a mean follow-up of 30.6 months (12-75). The fusion rate was 100%. No carpometacarpal arthropathy was noted. The mean position of the fused wrist was 11° extension and 15° ulnar tilt. There were two complications (7%): one postoperative hematoma and one case of discomfort due to impingement that required plate removal. The House score was significantly improved postoperatively (2.4 (0-5) versus 1.8 (0-4), p < 0.001), as was the INOM score (45 (12-64) versus 63 (36-84), p < 0.001). The patient satisfaction rate was 93%. The use of a simple and common material (volar plate in dorsal position) during this challenging surgery (spastic wrist contracture), provides good anatomical results and high patient satisfaction. LEVEL OF EVIDENCE: Level 4, case series, therapeutic study.

What can be expected from tendon transfers in the upper limb in central nervous system disorders?

In addition to motor deficits, central nervous system disorders combine major alterations in the motor pattern with spasticity and over time, contractures. Their varied clinical presentation makes their assessment and the therapeutic strategy more complex. For these reasons, tendon transfers in this population will have more limited indications and above all, will have to be integrated into a complex surgical program combining other procedures such as tendon lengthening, selective neurotomies and joint stabilization. The surgical strategy is far from being obvious. When faced with clinical presentations having very different objectives-functional or comfort only-it is difficult at first sight to build a standardized surgical program. We therefore propose a method to evaluate these patients, thanks to a score (INOM) that integrates prognostic factors and parameters to be corrected surgically. Three components guide this program: a prognostic factor (proximal motor control of the shoulder and elbow), correction of abnormal limb postures and restoration of active elbow, wrist and finger extension. The surgical strategy can be constructed from the INOM score which establishes the priorities for care. Nerve blocks and botulinum toxin injections are essential tools for this analysis. They help distinguish between spasticity and contracture, and can unmask certain antagonistic muscles. A tendon transfer in this population will be just as effective by the function it restores as by the action it suppresses in a malpositioned limb. For each joint, we describe the indications for tendon transfers and their relative role among the techniques with which they must be combined.

Tendon transfers to restore elbow flexion.

Elbow flexion paralysis is one of most significant deficiencies in the upper limb. When secondary to brachial plexus palsy or nerve trunk lesions, restoration of elbow flexion by means of early nerve surgery or palliative transfers should be part of a comprehensive treatment plan. Tendon transfers are indicated in long-standing palsies, in those who are poor candidates for nerve surgery or when the results of nerve surgery are inadequate. A regional pedicled muscle transfer is performed if available. In this case, a "strong" donor is preferred (pectoralis major with pectoralis minor transfer, triceps brachii to biceps brachii transfer, or bipolar latissimus dorsi transfer). A "weak" transfer is indicated in patients who have incomplete recovery of elbow flexion (MRC 2 strength): isolated pectoralis minor transfer, medial epicondylar muscle transfer according to Steindler technique, or advancement of biceps brachii tendon on forearm. When no donor muscle is available, a free reinnervated muscle transfer may be indicated if age and nerve regeneration conditions are favorable.

Palliative surgery for thumb involvement in ulnar paralysis.

Ulnar paralysis has multiple clinical presentations, which are due to partial recovery or to anatomical variations between the ulnar and median nerves. The main sequelae of ulnar nerve paralysis are the loss of hand strength with impairment of all intrinsic functions of the fingers and some of the thumb's functions. Weakness of the adductor pollicis and flexor pollicis brevis muscles may manifest as weak key pinch with automatic flexion of the thumb interphalangeal joint when gripping. Indications for palliative surgery have decreased due to advances in peripheral nerve surgery. However, palliative surgery still has a significant role to play when nerve repair techniques are not indicated or do not provide satisfactory results. The principle is to reinforce metacarpophalangeal flexion while stabilizing the thumb's interphalangeal joint, thus supplementing the action of the flexor pollicis brevis. This is generally done by transferring the flexor digitorum superficialis tendon of the fourth finger to the distal insertion of the superficial thenar muscles and the extensor pollicis longus. Restoration of the first dorsal interosseous is more rarely indicated.

Metacarpophalangeal joint instability in trapeziometacarpal osteoarthritis: A systematic review.

Thumb metacarpophalangeal instability is commonly found in conjunction with trapeziometacarpal osteoarthritis. If not corrected, it can have detrimental effects on the outcome. The authors describe the two types of metacarpophalangeal deformities - hyperextension and valgus - their pathophysiology and the surgical repair techniques available to surgeons. An algorithm for treating this instability is presented.

Radioscapholunate fusion for posttraumatic osteoarthritis with consecutive excision of the distal scaphoid and the triquetrum: A comparative study.

The aim of this study was to assess the clinical and radiographic outcomes after radioscapholunate (RSL) fusion for posttraumatic osteoarthritis. This was a retrospective, dual-center study of all patients who underwent RSL fusion between 1995 and 2015 for posttraumatic radiocarpal osteoarthritis. Patients were assessed at the final review to determine clinical (pain, wrist range of motion and strength), self-reported (QuickDASH, PRWE and MWS scores) and radiological (degenerative osteoarthritis in the scaphotrapeziotrapezoid (STT) or midcarpal joint and radiocarpal fusion) outcomes. We analyzed three groups: RSL fusion alone, RSL fusion with distal scaphoid excision (DSE) and RSL fusion with DSE and triquetrum excision (TE). Eighty-five patients were included; 10 were lost to follow-up and 11 required conversion to total wrist fusion before the final review. Finally, 64 patients had both clinical and radiographic evaluations. The mean follow-up was 9.1 years (range 1-21.4). RSL fusion alone was performed in 29 patients, RSL fusion with DSE in 23 and RSL fusion with DSE and TE in 12. At the final follow-up, the three groups did not differ in their pain or wrist motion. Overall, 47 (73%) patients were satisfied or very satisfied with the procedure. DSE significantly decreased STT osteoarthritis and radiocarpal non-union. The total wrist osteoarthritis rate after RSL fusion was 55%. RSL fusion is an effective procedure to preserve some motion in wrists with posttraumatic radiocarpal osteoarthritis. DSE prevents STT osteoarthritis by removing bony impingement and increases the fusion rate. LEVEL OF EVIDENCE: Level IV, Case series, Therapeutic studies.

Synthetic Elastography Using B-Mode Ultrasound Through a Deep Fully Convolutional Neural Network.

Shear-wave elastography (SWE) permits local estimation of tissue elasticity, an important imaging marker in biomedicine. This recently developed, advanced technique assesses the speed of a laterally traveling shear wave after an acoustic radiation force "push" to estimate local Young's moduli in an operator-independent fashion. In this work, we show how synthetic SWE (sSWE) images can be generated based on conventional B-mode imaging through deep learning. Using side-by-side-view B-mode/SWE images collected in 50 patients with prostate cancer, we show that sSWE images with a pixel-wise mean absolute error of 4.5 ± 0.96 kPa with regard to the original SWE can be generated. Visualization of high-level feature levels through t -distributed stochastic neighbor embedding reveals substantial overlap between data from two different scanners. Qualitatively, we examined the use of the sSWE methodology for B-mode images obtained with a scanner without SWE functionality. We also examined the use of this type of network in elasticity imaging in the thyroid. Limitations of the technique reside in the fact that networks have to be retrained for different organs, and that the method requires standardization of the imaging settings and procedure. Future research will be aimed at the development of sSWE as an elasticity-related tissue typing strategy that is solely based on B-mode ultrasound acquisition, and the examination of its clinical utility.

Evaluation of the effects of chronic occupational exposure to metallic mercury on the thyroid parenchyma and hormonal function.

INTRODUCTION: Experiments in animals exposed to mercury (Hg) in different chemical states have shown thyroid parenchymal and hormone alterations. However, these experiments did not allow the establishment of dose-response curves or provide an understanding of whether these Hg effects on the thyroid parenchyma occur in humans. OBJECTIVE: To evaluate the association between chronic occupational exposure to metallic Hg and alterations in thyroid hormones and gland parenchyma 14 years after the last exposure. METHODS: A cross-sectional study including 55 males exposed in the past to metallic Hg and 55 non-exposed males, paired by age, was conducted in the Hospital das Clínicas (Brazil) from 2016 to 2017. Serum concentrations of total and free triiodothyronine (TT3 and FT3), free thyroxine (FT4), thyrotropin (TSH), reverse T3 (RT3), selenium and antithyroid antibody titers were obtained. The Hg and iodine concentrations were measured in urine. The thyroid parenchyma was evaluated by B-mode ultrasonography with Doppler. The nodules with aspects suspicious for malignancy were submitted to aspiration puncture with a thin needle, and the cytology assessment was classified by the Bethesda system. The t test or Mann-Whitney test, Chi-square test and Spearman correlation were used to compare the exposed and non-exposed groups and examine the relationships between the variables. Univariate and multivariate logistic regression models were used to trace determinants of the risk of thyroid hormone alteration. Statistical significance was defined by p < 0.05. RESULTS: The urinary Hg average was significantly higher in the exposed group than in the non-exposed group (p < 0.01). The mean TSH serum concentration in the exposed group was higher, with a statistically significant difference between the groups (p = 0.03). Serum concentrations of TSH exceeded the normality limit (4.20 µIU/ml) in 13 exposed individuals (27.3%) and 4 non-exposed individuals (7.3%), with a statistically significant association between the hormonal increase and exposure to Hg (p = 0.02). In the logistic regression model, exposure to Hg (yes or no) showed an odds ratio = 4.86 associated with an increase of TSH above the normal limit (p = 0.04). The serum concentrations of RT3 showed a statistically borderline difference between the groups (p = 0.06). There was no statistically significant difference between the mean TT3, FT3 and FT4 serum concentrations in the Hg-exposed group compared to the non-exposed group. The proportions of the echogenicity alterations were higher in the exposed group compared to the non-exposed group (27.3% versus 9.1%; p = 0.03). Papillary carcinomas were documented in three exposed individuals and one non-exposed individual. A follicular carcinoma was recorded in one non-exposed individual. CONCLUSIONS: Due to the higher serum TSH concentration and the prevalence of parenchymal alterations in the Hg-exposed group, even after cessation of exposure, it is recommended that the thyroid status of exposed workers be followed for a long period.

Volar locking plate fixation of distal radius fractures: Isokinetic assessment of the influence of an ulnar styloid process fracture on pronation-supination strength.

Although distal radius fractures (DRF) are frequent, the management of associated ulnar styloid process (USP) lesions is still controversial. According to recent studies, a fracture of the USP does not appear to affect functional outcomes after treatment of a DRF with plate fixation. We sought to compare the impact of a USP fracture on pronation and supination strength in isometric and isokinetic tests. We included patients with a DRF who underwent volar locking plate fixation. We divided our population into three groups: one group consisted of patients who had a fracture of the USP base, one group composed of patients without USP fracture or with a distal ulnar fracture only, and a control group composed of subjects with normal wrists. Inclusion criteria included an age of 18 to 50 years and a minimum follow-up of 10 months post-surgery. The main exclusion criteria were complex intraarticular fractures and postoperative complications. The assessment was based on clinical examination and recording of forearm rotation strength during pronation and supination in isokinetic and isometric tests. The ratio between the operated and contralateral sides was compared for each patient. Thirty-six participants were included (mean age 31.1±4.5 years). The mean postoperative follow-up was 17.9±6.9 months. Participants with a USP fracture differed from other participants in their peak torque on the isokinetic test at 45°/s for pronation and supination, but not on isokinetic tests at 120°/s or in isometric tests. Isokinetic tests revealed a decrease in pronation-supination strength during sustained effort for patients with associated basal USP fractures. These findings may have clinical implications for management of the USP but need to be specified with further study. LEVEL OF EVIDENCE: prognostic study level III.

Black pigmentation of both forearm bones after chronic minocycline antibiotic therapy for septic nonunion. A case report and literature review.

We report the case of a 28-year-old man with a septic forearm non-union treated with minocycline for 3 months. At the time of reconstructive surgery, the radius and ulna were entirely black. Surgical debridement until bleeding of both bone extremities resulted in a 5-cm defect that was filled with a cement spacer. Histology confirmed poorly vascularized bone with focal areas of acute inflammatory infiltrate at the non-union sites (highly suggestive of infection) and normal structure of the remaining diaphyseal bones, although black in color. Reconstruction with free vascularized fibula transfer was successful leading to complete bone healing. An incidental finding of minocycline-induced black bone discoloration should not change the surgeon's decision because there is no evidence of adverse effects on bone healing in the literature. Surgery can be performed safely at sites of minocycline-induced black bone pigmentation.

Results and complications of superficialis-to-profundus tendon transfer in brain-damaged patients, a series of 26 patients.

INTRODUCTION: In hemiplegic patients with a spastic clenched fist deformity, one of the goals of surgery is to address the hygiene, nursing and appearance problems. Transfer of the flexor digitorum superficialis (FDS) to the flexor digitorum profundus (FDP), initially described by Braun and colleagues, opens the non-functional hand in these patients. The primary objective of our study was to confirm the effectiveness of this technique for correcting these deformities. The secondary objectives were to demonstrate potential functional gains and to identify potential complications. MATERIAL AND METHODS: A Braun procedure was performed in 26 patients (9 women, 17 men, ranging in age from 36 to 79 years). The overall appearance of the hand was graded using the Keenan classification system. Complications related to the surgery were documented. The hand's function was evaluated with the House score. RESULTS: The average follow-up was 47 months. Preoperatively, all patients had a class V hand: severe clenched-fist deformity with zero pulp-to-palm distance. Postoperatively, 10 patients had a type I hand (open hand, with less than 20° spontaneous extension deficit of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints) and 12 patients had a type II hand (20° to 40° spontaneous extension deficit of the MCP and PIP joints). The mean House score for all patients went from 0 to 0.88, and seven patients had functional improvements. Four patients had a forearm supination posture, 10 had intrinsic deformity with spontaneous MCP flexion and 6 had a swan-neck deformity. CONCLUSION: Superficialis-to-profundus tendon transfer (STP) provides satisfactory outcomes in terms of hand opening, with some patients also experiencing improved hand function. However, the complications cannot be ignored. LEVEL OF EVIDENCE: IV-retrospective or historical series.

Coracoid bone block transfer procedure: Correlation between subscapularis volume below the bone graft and shoulder stability.

INTRODUCTION: Coracoid bone graft transfer has become the gold standard in patients with recurrent anterior shoulder instability associated with bony defect. Several studies have shown that the main stabilizing component of this procedure is the sling effect by the conjoint tendon and the lower portion of subscapularis (SS). The purpose of this study was to determine whether a larger SS volume below the bone block was correlated to greater postoperative shoulder stability. MATERIALS AND METHODS: This prospective study included a cohort of patients who underwent open coracoid bone graft transfer for post-traumatic recurrent anterior shoulder instability. Forty patients were reviewed at 2 years with a clinical and CT scan evaluation. A correlation analysis assessed the relation between the SS volume index (ratio of SS volume below the bone block to volume over the bone block) and Rowe and Walch-Duplay instability scores. RESULTS: There exists a positive and significant correlation between SS volume index and postoperative Rowe score, r=0.37 (P=0.03). The same trend was observed for Walch-Duplay score without statistical significance. A larger inferior SS volume did not result in a limitation of external rotation, greater fatty infiltration, or malposition of the coracoid graft. CONCLUSION: A larger SS volume below the bone block is related to greater postoperative shoulder stability. We recommend performing the split in the middle of the SS or higher instead of the junction of the superior two-thirds and inferior one-third as usually reported. LEVEL OF EVIDENCE: III, prospective study.

Clinical outcomes of proximal row carpectomy by preoperative midcarpal joint morphological classification: Viegas type I versus type II.

The midcarpal joint can be classified into two anatomical types - Viegas type I and Viegas type II - based on the absence or presence of a medial facet for the hamate on the lunate (lunohamate facet). Type I is associated with a round capitate shape, which theoretically allows better congruence with the lunate fossa of the distal radius following proximal row carpectomy (PRC). This morphological feature has never been considered as a predictive factor of clinical outcome for this surgical procedure. This study aimed to compare the clinical and radiological outcomes of the two Viegas types following PRC. A retrospective single-center study was carried out on patients who underwent PRC for wrist osteoarthritis. Minimum follow-up was 2 years. Lunate type was determined based on preoperative CT arthrography. The clinical evaluation included range of motion (ROM) and strength as well as the functional DASH, Mayo Wrist scores and a VAS for pain. The outcome of radiocapitate osteoarthritis was assessed on plain radiographs. Forty patients were reviewed with a mean follow-up of 57 months. Twenty-one Viegas type I and 19 Viegas type II were identified on preoperative CT arthrography. The etiologies included 23 SLAC wrists (12 Viegas type I, 11 type II), 8 SNAC wrists (4 Viegas type I, 4 type II), 6 cases of Kienböck's disease (3 type IIIa, 3 type IIIb with 3 Viegas type I and 3 type II), 1 Preiser's disease and 2 cases of transscaphoid perilunate dislocation of the carpus. Patients with a Viegas type I lunate had significantly greater flexion-extension ROM: 83.5° vs. 71° (P=0.04) and radial deviation: 12° vs. 7° (P=0.013) than those with Viegas type II. However, three cases of complex regional pain syndrome (CRPS) were reported in the Viegas type II group vs. zero in the Viegas type I group. There were no differences between the two groups in terms of strength, functional scores or VAS pain. The outcome of radiocapitate osteoarthritis was similar in both groups. Considering the number of CRPS cases in the Viegas type II group and similar functional results in both groups, the worse outcomes of the Viegas type II patients in terms of ROM cannot be considered as clinically relevant. This comparative study does not provide a reasonable basis for concluding that Viegas type I patients are better candidates for PRC than Viegas type II patients.

Stener-like lesions due to radial collateral ligament rupture in the metacarpophalangeal joints of two adjacent fingers: A case report and review of literature.

Rupture of the collateral ligaments in the metacarpophalangeal (MCP) joint of a finger is less common than in the thumb. Literature about these lesions is sparse but the number of chronic injuries reported underlies the number of cases overlooked by physicians at the first visit. A Stener-like lesion is characterized by interposition of the extensor hood or the sagittal band between the torn collateral ligament of the MCP joint of a finger and its insertion. It was originally described as interposition of the adductor aponeurosis of the thumb. We present the first case of a Stener-like lesion in ruptured radial collateral ligaments of the MCP joint of two adjacent fingers.

[Carpal malalignment following distal radius fracture]. / Désaxations carpiennes adaptatives après fractures de l'extrémité distale du radius.

Adaptive carpal malalignment is the consequence of malunion of the distal radius. Since the radial metaphysis and capitate have to be aligned, any disorientation of the radial epiphysis will force the proximal carpal row to adapt, as it is the only mobile element. There are two types of adaptation depending where the compensative occurs: (1) midcarpal - leading to flexion between the lunate and capitate, with the lunate maintaining a normal relationship with the radial epiphysis axis; (2) radiocarpal - combining flexion and dorsal displacement of the lunate relative to the axis of the radial epiphysis, with the midcarpal joint remaining aligned. Clinically, adaptive carpal malalignment is not the first reason for consultation in cases of distal radius malunion. It occurs in cases of moderate deformity with preserved pronation-supination in a young patient who has good mobility. It generates dorsal pain that may be associated with a snapping sensation. The diagnosis requires strict lateral X-ray views. Over time, the wrist becomes stiff but analgesic and is often well tolerated functionally. This type of deformity has not been shown to lead to osteoarthritis. Osteotomy to correct the malunion is the only way to treat adaptive carpal malalignment in active young patients who have a mobile but painful wrist.

[Extra-articular distal radius fractures in young adults]. / Fractures extra-articulaires de l'extrémité distale du radius chez l'adulte jeune.

Extra-articular distal radius fractures in young active patients are typically the result of sport injuries or traffic accidents. Displaced fractures are less well tolerated in young patients than in older people, especially in terms of dorsal tilt and radial shortening. Non-surgical treatment is only indicated when the fracture is minimally or not displaced. No fracture fixation method is superior to another, however, the treatment goal is a rapid return to previous activities.

Extensive limb-sparing surgery with reconstruction for sarcoma of the hand and wrist.

BACKGROUND: Sarcoma rarely involves the hand or wrist. Extensive surgical excision is the current standard of care. At the extremities, such as the hand and wrist, limb-sparing surgery with reconstruction to provide optimal function is increasingly performed. A descriptive case-series study of 16 patients with sarcoma of the hand and wrist managed using limb-sparing surgery is reported here. MATERIAL AND METHODS: Of 19 patients with sarcoma of the hand or wrist treated between 1999 and 2012, 16 were managed using limb-sparing surgery. These were consecutive patients managed at a single-centre and studied retrospectively. The tumour involved the hand in 7 patients and the wrist in 9 patients. The procedure was primary in 6 patients, whereas 10 patients underwent secondary revision surgery. In 12 patients, reconstruction was performed for one or more of the following structures: nerves (n=2), tendons (n=3), bone (n=3), and/or skin (n=8). After surgical excision, the margins were R0 in 15 patients and R1 in 1 patient. At last follow-up, survival, pain, and function as reflected by the DASH and MSTS scores were assessed. RESULTS: After the median follow-up of 4.5years [1-13], 15 patients were alive with no local recurrence and 1 patient had lung metastases. Mean values were 18 [0-49] for the DASH score and 88.8% [53-100] for the MSTS score. DISCUSSION: Limb-sparing surgery reconciles the need to achieve complete tumour excision with the need to restore function. No limits should be placed on tumour excision, given the availability of effective reconstructive methods. The functional outcome depends on the tolerance of adjuvant treatments, most notably radiotherapy. LEVEL OF EVIDENCE: IV, retrospective study.