Management of high grade renal trauma: 20-year experience at a pediatric level I trauma center.

PURPOSE: In the last 20 years the management of high grade, blunt renal trauma at our institution has evolved from primarily an operative approach to an expectant nonoperative approach. To evaluate our experience with the expectant nonoperative management of high grade, blunt renal trauma in children, we reviewed our 20-year experience regarding evaluation, management and outcomes in patients treated at our institution. MATERIALS AND METHODS: We retrospectively studied all patients sustaining renal trauma between 1983 and 2003. Medical records were reviewed for mechanism of injury, assigned grade of renal injury, patient treatment, indications for and timing of surgery, and outcome. Injuries were categorized as either low grade (I to III) or high grade (IV to V). RESULTS: We reviewed the medical records of 164 consecutive children who sustained blunt renal trauma between 1983 and 2003. A total of 38 patients were excluded for inadequate information. Of the remaining 126 children 60% had low grade and 40% had high grade renal injuries. A total of 11 patients (8.7%) required surgical or endoscopic intervention for renal causes, including 2 for congenital renal abnormalities and 1 for clot retention. Eight patients (6.3%) required surgical intervention for isolated renal trauma, of whom 2 (1.6%) required immediate surgical intervention for hemodynamic instability and 6 (4.8%) were treated with a delayed retroperitoneal approach. Only 4 patients (3.2%) required nephrectomy. All patients receiving operative intervention had high grade renal injury. CONCLUSIONS: Initial nonsurgical management of high grade blunt renal trauma in children is effective and is recommended for the hemodynamically stable child. When a child has persistent symptomatic urinary extravasation delayed retroperitoneal drainage may become necessary to reduce morbidity. Minimally invasive techniques should be considered before open operative intervention. Early operative management is rarely indicated for an isolated renal injury, except in the child who is hemodynamically unstable.

MRI imaging of fetal neck masses with airway compromise: utility in delivery planning.

We present two cases of fetal neck masses that were initially diagnosed by ultrasound and further evaluated with prenatal MRI. MRI findings aided in further delineating the neck masses, increasing confidence in the final diagnosis (cervical teratoma and cystic hygroma). With the fetal airway typically filled with fluid that is of high signal on T2-weighted sequences, MRI images in three planes could identify whether the fetal larynx and trachea were partially or completely compressed by the neck tumor. This information was particularly useful in determining if a controlled delivery such as ex utero intrapartum treatment (EXIT) was necessary and aided the surgeons in planning their approach to establishing airway control in the delivery room.

Transcranial Doppler (TCD) screening for stroke prevention in sickle cell anemia: pitfalls in technique variation.

BACKGROUND: The Stroke Prevention Trial in Sickle Cell Anemia (STOP) identified children as being at high stroke risk if the time-averaged maximum mean velocity (TAMMV) of the middle cerebral or intracranial internal carotid arteries measured > or = 200 cm/s. These values were obtained utilizing a 2-mHz dedicated nonimaging pulsed Doppler technique (TCD) and manual measurements. Questions have been raised as to the comparability of results obtained with different ultrasound machines and measurement techniques. OBJECTIVE: The purpose of this study was to compare nonimaging (TCD) and transcranial duplex imaging (TCDI) findings in children potentially at risk for stroke with sickle cell disease. MATERIALS AND METHODS: Twenty-two children with sickle cell disease and no history of stroke were evaluated by both TCD and TCDI. Examinations were performed on the same day without knowledge of the other modality results and read independently using manually obtained measurements. Mean velocities, peak systolic velocities, and end diastolic velocities obtained by the two techniques were compared. In a subgroup, manual measurements were compared to electronically obtained measurements. RESULTS: TCDI values were lower than TCD measurements for all vessels. TCDI TAMMV values were most similar to the TCD values in the middle cerebral artery (-9.0%) and distal internal cerebral artery (-10.8%), with greater variability in the anterior cerebral artery (-19.3%), bifurcation (-16.3%), and basilar arteries (-23.1%). Risk group placement based on middle cerebral artery TAMMV values did not change when comparing the two techniques. Measurements obtained electronically were lower than those obtained manually. CONCLUSION: Velocities obtained by TCDI may be lower than TCD measurements, and these differences should be taken into consideration when performing screening for stroke risk and selection for prophylactic transfusion based on the STOP protocol.

Inflammatory bowel disease in children and young adults: correlation of sonographic and clinical parameters during treatment.

OBJECTIVE: The objective of this study was to evaluate the sonographic findings of inflammatory bowel disease activity in children undergoing treatment. SUBJECTS AND METHODS: Eighty-eight sonograms were obtained of 23 bowel segments in 17 children and young adults (age range, 10-21 years; mean, 16 years) with new or recurrent inflammatory bowel disease. Sixteen segments were involved with Crohn's disease and seven with ulcerative colitis. Serial sonography (range, two to eight examinations; mean, four per segment) was performed while patients underwent treatment. Bowel wall thickness measurements and color and power Doppler sonography grading were recorded and compared with clinical data. RESULTS: All 17 patients had at least one abnormal bowel segment on initial sonography. The correlation was significant (p < 0.01). Agreement was 91% on direction of change over time between bowel wall thickness and Doppler grades, with 100% correlation between color and power Doppler sonography grades. In patients with Crohn's disease, the correlation was significant (p < 0.05) between bowel wall thickness and Doppler grades with two of seven and four of seven clinical parameters, respectively. In patients with ulcerative colitis, the correlation was significant (p < 0.05) between bowel wall thickness and Doppler sonography grades with four of seven and three of seven clinical parameters, respectively. The erythrocyte sedimentation rate correlated with all sonographic measurements in both patient groups. Combining bowel wall thickness and Doppler sonography, the percentage of agreement was significant in the direction of change, with five of seven clinical parameters in both patient groups. CONCLUSION: Gray-scale and color or power Doppler sonography can show changes in disease activity in children and young adults undergoing treatment for inflammatory bowel disease.

Pancreatoblastoma: imaging findings in 10 patients and review of the literature.

PURPOSE: To describe the features of pancreatoblastoma at magnetic resonance (MR) imaging, computed tomography (CT), and ultrasonography (US). MATERIALS AND METHODS: Imaging and surgical findings in 10 patients (age range, 2-20 years; mean age, 6.8 years) with pathologically proved pancreatoblastoma were reviewed for tumor size, organ of origin, definition and quality of tumor margins, tumor heterogeneity, calcification, enhancement, ascites, biliary and/or pancreatic ductal dilatation, local invasion, adenopathy, vascular invasion, vascular encasement, metastases, and signal intensity on MR images. Results from 10 CT, seven US, and three MR imaging examinations were reviewed. RESULTS: Five of the 10 tumors were pancreatic; four others appeared to be pancreatic or hepatic. Most had well-defined margins (nine of 10), were heterogeneous (nine of 10), and enhanced (10 of 10). Other findings included calcification (two of 10), biliary and pancreatic ductal dilatation (one of 10), and ascites (three of 10). Hepatic (two patients) and pelvic (two patients) metastases were present. Adenopathy (two patients) and vascular invasion (one patient) were not identified radiologically. Tumors had low to intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. CONCLUSION: Pancreatoblastoma is typically a heterogeneous tumor with well-defined margins that may appear to arise from the pancreas or liver. It may behave aggressively, with localized vascular or bowel invasion or with widespread metastatic disease. Although it is rare, it should be considered in the differential diagnosis of an upper abdominal mass in a child.

Preterm anoxic injury. Radiologic evaluation.

Diagnostic imaging plays an important role in evaluating the preterm infant with hypoxic-ischemic injury. The pathologic and radiographic findings of IVH, focal white matter necrosis, and severe anoxic damage are well documented. New observations, including diffuse white matter and cerebellar insults in some survivors, are being made. Understanding the complex relationships between these findings, clinical events (both prenatal and postnatal), and neurocognitive outcome of the preterm infants, however, requires further study.

Bladder distention and pyelectasis in the male fetus: causes, comparisons, and contrasts.

The objective of this paper was to determine if prenatal sonographic findings can accurately differentiate between the causes of bladder distention and pyelectasis in the male fetus. Twenty-one cases were evaluated for the presence of oligohydramnios, posterior urethral dilation, bladder wall thickening, urachal patency, cortical thinning, cortical cysts, and increased renal echogenicity. Postnatal diagnosis included posterior urethral valves (10 cases), prune belly syndrome (four cases), vesicoureteral reflux (four cases), left ureterovesical junction obstruction (one case), and nonrefluxing, nonobstructive megacystis-megaureter (two cases). Oligohydramnios was present in eight of 10 cases of posterior urethral valves and in one of four cases of prune belly syndrome. A dilated posterior urethra was noted in seven of 10 cases of posterior urethral valves and transiently in two of four cases of prune belly syndrome. Bladder wall thickening developed in all cases of posterior urethral valves and was noted in two of four patients with prune belly syndrome. A patent urachus likewise was identified in two of four cases of prune belly syndrome. The presence of oligohydramnios, progressive bladder wall thickening, and dilated posterior urethra was most suggestive of posterior urethral valves, whereas the presence of a patent urachus was most suggestive of prune belly syndrome. The presence of pyelectasis and megacystis without additional amniotic fluid, bladder, urethral, or renal abnormalities was most suggestive of vesicoureteral reflux, ureterovesical junction obstruction, or nonrefluxing, nonobstructive megacystis-megaureter. Owing to the overlap and evolution of these findings, close follow-up evaluation is recommended.

Pattern of neuropsychological deficit at age five years following neonatal unilateral brain injury.

The pattern of language deficit following left-hemisphere brain injury and visual/spatial deficit following right-hemisphere injury in an adult or older child is well recognized, but has been inconsistently reported following presumed neonatal brain injury. Our prospective study of 24 children at age 5 with documented neonatal unilateral brain injury lends support to the theory of hemisphere specialization at the time of birth. Twelve children who had unilateral left-hemisphere lesion were compared to 12 children with unilateral right-hemisphere lesion of similar timing and severity. Relative visual/spatial deficit following right-hemisphere lesion and receptive language deficit following left-hemisphere lesion were identified. Lateralized measures of grip strength, fine motor speed, and fine motor dexterity were not significantly different between the groups for either hand in this nonhemiparetic study sample. Only one child with a left-hemisphere lesion was left-handed, and only one child (right-lesion) had a hemiparesis.

Peak enhancement of the liver in children using power injection and helical CT.

OBJECTIVE: Our objective was to determine the level and timing of peak hepatic enhancement in children using power injection of contrast media, helical CT, and computer-automated scan technology. SUBJECTS AND METHODS: Forty-nine abdominal CT studies were performed using computer-automated scan technology. Patients were divided into four groups on the basis of body weight and contrast dose (group 1A, < or = 20 kg and 2 ml/kg; group 1B, < or = 20 kg and 3 ml/kg; group 2, 21-40 kg and 2 ml/kg; group 3, > 40 kg and < or = 2 ml/kg). Contrast injection rates were based on body weight (groups 1A and 1B, 1 ml/sec; group 2, 1.5 ml/sec; and group 3, 2 ml/sec). The peak hepatic enhancement level in Hounsfield units and the time to reach peak enhancement were determined for each patient. RESULTS: The mean peak hepatic enhancement and time to peak enhancement after completion of contrast injection were group 1A, 45 H and 11 sec; group 1B, 62 H and 3 sec; group 2, 52 H and 12 sec; and group 3, 45 H and 10 sec. CONCLUSION: The level and timing of peak hepatic enhancement in pediatric patients can be obtained using computer-automated scan technology. These data may then be used to optimize hepatic enhancement when obtaining helical abdominal CT scans of pediatric patients.

Multicenter study of surfactant (beractant) use in the treatment of term infants with severe respiratory failure. Survanta in Term Infants Study Group.

OBJECTIVE: The purpose of this study was to determine whether surfactant (beractant) administration to term newborns in respiratory failure and at risk for requiring extracorporeal membrane oxygenation (ECMO) treatment would significantly reduce the incidence of severe complications through 28 days of age and the need for ECMO. STUDY DESIGN: A multicenter (n = 44), randomized, double-blind, placebo-controlled trial was conducted. Infants weighing 2000 gm or more with gestational ages of 36 weeks or greater were stratified by diagnosis (meconium aspiration syndrome, sepsis, or idiopathic persistent pulmonary hypertension of the newborn) and oxygenation index (15 to 22, 23 to 30, 31 to 39) and then randomly assigned to receive four doses of beractant, 100 mg/kg (n = 167), or air placebo (n = 161) before ECMO treatment and four additional doses during ECMO, if ECMO was required. The incidence of untoward effects (including hemorrhagic, neurologic, pulmonary, renal, cardiovascular, infectious, metabolic, and technical complications) occurring before and after randomization and through 28 days of age or discharge were recorded. RESULTS: The two treatment groups were comparable in baseline parameters, including birth weight, sex, gestational age, oxygenation index, and primary diagnosis. There was no difference in the incidence of severe complications. The need for ECMO therapy was significantly less in the surfactant group than in the placebo group (p = 0.038); this effect was greatest within the lowest oxygenation index stratum (15 to 22; p = 0.013). CONCLUSIONS: Use of surfactant, particularly in the early phase of respiratory failure, significantly decreases the need for ECMO in the treatment of term newborns with respiratory failure, without increasing the risk of complications.

Traumatic aortic injuries in children: radiologic evaluation.

OBJECTIVE: The purpose of this study was to evaluate the radiographic findings in children with traumatic aortic injuries and discuss the imaging techniques currently available for diagnosis. MATERIALS AND METHODS: A retrospective review of 10,886 children examined because of blunt trauma from 1987 to April 1996 identified seven patients (0.064%) who sustained traumatic aortic injuries. The mechanism of injury, location of aortic injury, additional injuries suffered, trauma scores, sequences of radiologic evaluation, imaging findings, treatment, and outcome were recorded for each child. RESULTS: Six children had pathologically proven aortic ruptures, and the remaining child had an intimal injury diagnosed with contrast-enhanced helical CT and confirmed with transesophageal echocardiography. All seven children were victims of motor vehicle accidents (six passengers, one pedestrian), all had injuries of the aortic isthmus, and all had additional severe injuries. The mean trauma score, injury severity score, and probability of survival were 14, 39, and 75%, respectively. Imaging techniques included chest radiography (n = 7), conventional CT (n = 1), helical CT (n = 3), aortography (n = 2), and transesophageal echocardiography (n = 3). The initial outcomes included death (n = 1), paraplegia (n = 1), paraparesis (n = 2), and recovery without morbidity (n = 3). CONCLUSION: Traumatic aortic injuries are rare in children. The most common findings on plain films are a left apical cap, pulmonary contusion, aortic obscuration, and mediastinal widening. Helical CT and transesophageal echocardiography can be used in the diagnosis of traumatic aortic injuries in children.

Severity of brain injury following neonatal extracorporeal membrane oxygenation and outcome at age 5 years.

Neurodevelopmental evaluation in childhood provides an opportunity to study complex neurological compensation following documented neonatal brain injury, and furnishes important clinical information which may have an impact on patient care. We studied 152 term children treated with extracorporeal membrane oxygenation (ECMO) as neonates and who received routine neonatal neuroimaging and comprehensive neurodevelopmental evaluation at age 5 years. The cohort was divided into four groups based on an independent neuroimaging score: No lesion, N=88; Mild lesion, N=38; Moderate lesion, N=12; and Severe lesion, N=14. Standardized testing at age 5 included complete neuropsychological assessment, neurological evaluation, and assessment of motor function. All testing was conducted without knowledge of the neuroimaging score. The occurrence of disability by severity of neuroimaging was: No lesion=10%; Mild=13%; Moderate=33%; Severe=57%. The relative risk within the ECMO population for disability at age 5 after moderate or severe neonatal lesion was 4.3 (CI=1.0 to 17.5) and 11.7 (CI=3.3 to 41.3), respectively. The remaining non-disabled children who had moderate to severe lesions functioned within normal limits. Severity of neonatal neuroimaging was inversely associated with IQ scores, pre-academic skills, and neuromotor function. The effect size was small but the rank order was predictable. Our data identify in 5-year-old children an impact of brain lesion severity demonstrated on routine neonatal neuroimaging. The results indicate potential compensation following moderate and severe lesions, and suggest a subtle but consistent influence of even mild neonatal brain injury.

Prenatal evaluation of fetal anomalies.

Advances in sonographic imaging have allowed for detailed examination of the fetus. A wide range of abnormalities of the fetal central nervous system, chest, gastrointestinal tract, genitourinary system, and skeleton are detectable by prenatal sonography. This article reviews the sonographic findings and prognostic implications of these abnormalities.

In-line pressures generated in small-bore central venous catheters during power injection of CT contrast media.

PURPOSE: To determine in-line pressures generated in small-bore central venous catheters during power injection of computed tomographic (CT) contrast media. MATERIALS AND METHODS: Five 3.0-7.0-F central venous catheters for pediatric patients were tested at full and half lengths in vitro. In-line pressures were measured during power injection of three contrast media. Rates of injection were increased in steps from 0.1 to 5.0 mL/sec or until a peak pressure of 100 psi (700 kPa) was achieved. The maximum tolerated flow rate was determined with reference to the manufacturer's suggested operating pressure limit for each catheter. RESULTS: At full length, the maximum tolerated flow rates were as follows: 2-3 mL/sec for the large lumen and 1-1.4 mL/sec for the small lumen of the 7.0-F double-lumen catheter; 0.2-0.4 and 0.8-1.2 mL/sec for the 3.0- and 4.0-F peripherally inserted central catheters, respectively; 0.7-1.2 mL/sec for the 6.6-F catheter; and only 0.2 mL/sec for the 4.2-F catheter, which ruptured during testing at higher flow rates. CONCLUSION: Flow rates were documented at which certain small-bore central venous catheters should tolerate power injection of CT contrast media with peak pressures remaining below the manufacturer's recommended operating pressure limits. These data may serve as a guide for clinical use.

Extracorporeal membrane oxygenation exposes infants to the plasticizer, di(2-ethylhexyl)phthalate.

OBJECTIVES: To determine the exposure to, and evaluate the potential toxicity from, the plasticizer, di(2-ethylhexyl)phthalate (DEHP) during extracorporeal membrane oxygenation (ECMO) therapy. DESIGN: Protocol 1 consisted of a prospective comparison of three ECMO circuit designs in vitro. Protocol 2 consisted of a prospective, comparative clinical study evaluating DEHP plasma concentrations in ECMO vs. non-ECMO patients with respiratory failure. SETTING: Neonatal intensive care unit at The Children's National Medical Center, Washington, DC. PATIENTS: In protocol 2, 28 consecutive term infants were referred for ECMO therapy. Eighteen infants required ECMO; ten control patients received conventional ventilation and improved without ECMO. INTERVENTIONS: In protocol 1, three ECMO circuit designs were primed in vitro with normal saline, albumin, and human blood, which was maintained at 37 degrees C and recirculated at 400 mL/min for 48 hrs. Plasma samples were obtained at time 0, 1 hr, and every 6 hrs. In protocol 2, ventilatory and cardiovascular management of the patients in the study was conducted by the attending physician. Patients were placed on ECMO when they met the institutional criteria for ECMO therapy. Daily plasma concentrations for DEHP were collected until 3 days after decannulation from bypass in the ECMO group. Control patients were sampled daily until extubation. Evidence of cardiac, liver, or lung toxicity was evaluated by Chest Radiographic Scores, liver function studies, and echocardiograms obtained on day 1, day 3, and the day of decannulation in the ECMO group, or at the time of extubation in the control group. Sedation, blood product transfusions as indicated, antibiotics, and hyperalimentation were administered to all patients. MEASUREMENTS AND MAIN RESULTS: All DEHP plasma concentrations were measured by gas chromatography. In protocol 1, three circuits were studied: circuit A (small surface area); circuit B (larger surface area); and circuit C (surface area of A but with heparin-bonded tubing in the circuit). DEHP leached from circuit A at 0.32 +/- 0.12 microgram/ mL/hr, compared with 0.57 +/- 0.14 microgram/mL/hr from circuit B (p < .05). This amount of DEHP extrapolates in the ECMO patient to a potential exposure of 20 to 70 times that exposure from other medical devices or procedures, such as transfusions, dialysis, or short-term cardiopulmonary bypass. Circuit C showed almost no leaching from the circuit; DEHP concentrations decreased at a rate of 0.2 +/- 0.04 microgram/mL/ hr. In protocol 2, DEHP was undetected in the control patients. DEHP concentrations in ECMO patients were greater in the early course of ECMO. However, most patients cleared this compound from the plasma before decannulation. In contrast to the in vitro results in protocol 1, the average highest concentration at any time on bypass was 8.3 +/- 5.7 micrograms/mL or 2 mg/kg. CONCLUSIONS: DEHP leaches from ECMO circuits, with potential exposure concentrations related to the surface area of the tubing in the ECMO circuit. Heparin bonding of the tubing eliminates this risk. Although significant concentrations of DEHP leach from the nonheparin-bonded circuits over time, our in vivo studies showed that the DEHP plasma concentrations were less than the previously reported values and do not correlate with any observable short-term toxicity. This compound may be either efficiently metabolized by the newborn, or redistributed into various tissues. Although signs of toxicity were not found in this study, long-term complications from chronic exposure to DEHP have not been determined.

Intracranial abnormalities in infants treated with extracorporeal membrane oxygenation: update on sonographic and CT findings.

PURPOSE: To determine the frequency of intracranial lesions in infants treated with extracorporeal membrane oxygenation (ECMO), to evaluate trends in frequency during an 8-year period, and to determine which infants are at highest risk for intracranial injury. METHODS: Daily sonograms were obtained in 386 infants during treatment with ECMO. Cranial CT scans were acquired after decannulation in 286 of 322 survivors. Abnormalities were classified as major or minor and hemorrhagic or nonhemorrhagic. Results were correlated with infant demographic data. RESULTS: Intracranial abnormalities were detected in 203 (52%) of the 386 infants; 73 (19%) hemorrhagic, 86 (22%) nonhemorrhagic, and 44 (11%) combined lesions. Eighty-two lesions (21%) were classified as major. Forty-six (94%) of 49 major hemorrhages were identified at sonography. CT contributed additional information in 73% of neonates with intracranial abnormalities, of which 17 were major lesions not identified at sonography. The frequency of intracranial hemorrhage was increased in infants who were septic or premature or weighed less than 2.5 kg. An increase in time spent on ECMO bypass increased the risk for nonhemorrhagic injury. During an 8-year period, the frequency of hemorrhagic and major nonhemorrhagic lesions remained constant, whereas minor nonhemorrhagic abnormalities increased significantly. CONCLUSION: Infants treated with ECMO continue to be at high risk for cerebrovascular injury. Although daily sonograms are useful in identifying major hemorrhages, follow-up CT scans are crucial for accurate evaluation of intracranial abnormalities.

Ectrodactyly, diaphragmatic hernia, congenital heart defect, and agenesis of the corpus callosum.

A unique case of a female born with four major malformations, ectrodactyly, diaphragmatic hernia, ventricular septal defect, and agenesis of the corpus callosum is reported. The patient had a normal birth weight, normal head circumference and a normal karyotype. There was no significant facial dysmorphism. The family history was unremarkable for birth defects, recurrent pregnancy loss, limb anomalies or consanguinity. We propose that this represents a new constellation of multiple malformations.

Patient with craniosynostosis and marfanoid phenotype (Shprintzen-Goldberg syndrome) and cloverleaf skull.

Marfanoid phenotype with craniosynostosis (Shprintzen-Goldberg syndrome) is a rare disorder previously described in only 5 patients. We report on the sixth known patient with this condition. The findings which distinguish our patient from others reported previously are that she was ascertained prenatally as having a cloverleaf skull; this is the first female patient described with this condition. Postnatally, she presented with arachnodactyly, camptodactyly, and clover-leaf skull. Imaging studies of the brain documented microcephaly with malformed brain, hydrocephaly, and hypoplasia of the corpus callosum. She also had choanal atresia and stenosis, a clinical finding previously reported only once, in this disorder.

Splenic injury from blunt abdominal trauma in children: follow-up evaluation with CT.

PURPOSE: To assess if the initial grade of splenic injury depicted at computed tomography (CT) in children could help predict rate of healing. MATERIALS AND METHODS: Thirty-seven children with splenic injury graded at emergent CT were prospectively followed up with non-enhanced and contrast material-enhanced CT performed 2 weeks to 11 months after injury. RESULTS: In all 15 grade 1 and 2 splenic injuries, healing was seen at follow-up, including eight injuries that occurred in patients who underwent follow-up CT within 4 months. In 10 of 11 grade 3 splenic injuries, healing was seen within 6 months. In all 11 grade 4 injuries, residual lesions were seen within 4 months and healing took up to 11 months. Five of nine residual splenic injuries were more clearly visualized with contrast material enhancement. No splenic complications occurred. CONCLUSION: CT grade of splenic injury is related to rate of healing. Grade 1 and 2 injuries typically heal within 4 months, whereas grade 3 injuries take up to 6 months to heal and grade 4 injuries take up to 11 months.