The Use of Carbon Fiber Implants for Impending or Existing Pathologic Fractures.

OBJECTIVES: To evaluate the utility and complications of using carbon fiber implants (CFIs) compared with standard titanium alloy (TI) intramedullary implants for stabilization of impending or existing pathologic fractures. DESIGN: Retrospective comparison. PATIENTS/PARTICIPANTS: Ninety-four patients undergoing intramedullary fixation of 100 impending or existing pathologic fractures between 2014-2019 were identified for inclusion. MAIN OUTCOME MEASUREMENTS: The primary outcome was postoperative complications. Other outcomes included implant type, pathology, indication, and adjuvant therapy. RESULTS: Fifty-three percent of cases used a CFI, whereas 47% of cases used a TI. There were no differences between groups with regard to anatomic location (P = 0.218), indication for surgery (P = 0.066), histology (P = 0.306), or postoperative adjuvant therapy (P = 0.308). Nineteen percent of cases incurred a postoperative complication in each group (P = 0.530), and no differences were noted with regard to complication type including implant failure (P = 0.442) and wound complications (P = 0.322). There was a cost saving of $400 with TI implants compared with CFI. CONCLUSIONS: This is a high-risk population for postoperative complications after stabilization of pathologic fractures. Although there were no statistical differences in complications between CFI and TI, implant choice depends on patient characteristics and surgeon preference. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Resident Level Involvement Affects Operative Time and Surgical Complications in Lower Extremity Fracture Care.

OBJECTIVE: The purpose of this study is to evaluate the effect of resident participation on operative time and surgical complications in isolated lower extremity fracture care. SETTING: Patients who were treated at teaching hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program database. PARTICIPANTS: A total of 2,488 patients who underwent surgical fixation of isolated hip fractures, femoral or tibial shaft fractures, and ankle fractures. DESIGN: Patients were stratified by surgical procedure and post-graduate year (PGY) of the resident involved. Total operative time and surgical complications were analyzed with respect to resident participation and seniority. Multivariable logistic regression analyses were used to adjust for potential confounders including case complexity, wound class, and patient comorbidity burden. RESULTS: As PGY level increased, operative time increased for each procedure. The odds for a deep surgical site infection decreased as resident seniority increased, but the odds for wound dehiscence increased as resident seniority increased. We found no difference in the incidences of superficial infections or return to the OR with respect to PGY level. Academic quarter within the academic year did not correlate with any of the surgical complications. Furthermore, when cases performed with residents were compared to those performed without residents, there was no increased risk of superficial infections, deep infections, or return to the OR. CONCLUSIONS: This nationally representative dataset demonstrates that operative times for lower extremity orthopedic trauma increased as resident seniority increased. Additionally, senior resident participation was associated with increased wound dehiscence, whereas junior resident participation was associated with an increased risk of deep surgical site infections. However, there was no associated "July effect" for residents at any level of training and there was no increased risk for surgical site infections or return to the OR in cases involving resident participation.

Insulin-Dependence Predicts Surgical Complications and Hospital Admission following Knee Arthroscopy.

While prior studies have demonstrated that insulin-dependence is an independent risk factor for postoperative complications, morbidity, and mortality following spine and shoulder, hip, and knee arthroplasty, it has not been evaluated in the setting of knee arthroscopy. Therefore, the purpose of this study is to compare the risk of postoperative complications among patients with insulin-dependent diabetes mellitus and noninsulin-dependent diabetes mellitus (IDDM and NIDDM respectively) with the general population following knee arthroscopy. A retrospective analysis of the National Surgical Quality Improvement Program's database for the years 2005 to 2016 was conducted. Logistic regression analyses were used to assess the relationship between diabetic status and outcomes. Multivariate models were established to adjust for age, sex, body mass index, hypertension, congestive heart failure, chronic obstructive pulmonary disease, smoking status, American Society of Anesthesiology classification, and functional status. A total of 86,023 patients were identified. Patients with IDDM were at a much higher risk of surgical complications (odds ratio [OR]: 2.186, 95% confidence interval [CI]: 1.226-1.157), including deep infections (OR: 3.082, 95% CI: 1.753-5.419) and return to operating room [OR] (OR: 1.933, 95% CI: 1.280-2.919), as well as unplanned hospital admission (OR: 1.770, 95% CI: 1.289-2.431). However, NIDDM was not an independent risk factor for subsequent medical or surgical complications, unplanned hospital admission, or 30-day mortality. Patients with IDDM were much more likely to have surgical complications, including deep infection and return to OR, as well as unplanned hospital admission following knee arthroscopy. These risks diminished among those with NIDDM, with their adjusted risk profiles comparable to those without diabetes. Since diabetes occurs in a heterogenous state, more weight should be given to those with insulin-dependence when risk-stratifying patients for surgery. This is a Level III, retrospective comparison study.

MRI diagnosis of rubber band constriction syndrome.

Rubber band syndrome is caused by constriction of the wrist from elastic bracelets worn for decorative purposes. Overtime, the fixed or elastic band burrows into the skin and becomes invisible. We present the case of a 2.5-year-old female child presenting to our institution with signs of circumferential swelling and inflammatory changes about the right wrist. MRI of the wrist demonstrated a subcutaneous circular foreign body, which was confirmed at surgery to be a rubber band. Although this disease entity is rare, radiologists can be instrumental in suggesting this diagnosis based on the location involved, ie, wrist, and the imaging findings.

Notable Racial and Ethnic Disparities Persist in Lower Extremity Amputations for Critical Limb Ischemia and Infection.

INTRODUCTION: The purpose of this study is to investigate the current disparities for major lower extremity amputation in patients with critical limb ischemia (CLI) and infection. METHODS: A retrospective analysis of the National Surgical Quality Improvement Program's database for the years 2011 to 2017 was conducted. Multivariate models were used to isolate the effect of race and ethnicity on the likelihood of a below-knee or above-knee amputation (BKA and AKA, respectively) for CLI secondary to type 2 diabetes mellitus, atherosclerosis, peripheral vascular disease, chronic osteomyelitis, and deep soft-tissue infections. RESULTS: For all diagnoses, blacks were 93.3%, and Hispanics were 61.9% more likely to undergo a BKA than white patients (P < 0.001). In addition, black patients had a 133.0% higher risk of an AKA than white patients (P < 0.001). Disparities were greatest with blacks undergoing surgery for CLI secondary to atherosclerosis (BKA odds ratio 2.093; AKA: odds ratio 2.625). Black patients also had an elevated risk of amputation secondary to diabetes, peripheral vascular disease, and deep soft-tissue infections (P < 0.001). DISCUSSION: This nationally representative, cohort-based study demonstrates that notable racial and ethnic disparities for lower extremity amputations persist, with a higher proportion of black and Hispanic patients undergoing amputation compared with limb salvage procedures for atraumatic CLI and infection. LEVEL OF EVIDENCE: Level III prognostic.

The 5-Factor Modified Frailty Index Predicts Complications, Hospital Admission, and Mortality Following Arthroscopic Rotator Cuff Repair.

INTRODUCTION: The purpose of this study is to evaluate the utility of the modified frailty index-5 (mFI-5) as a predictor for postoperative complications in patients undergoing arthroscopic rotator cuff repair (RCR). METHODS: The National Surgical Quality Improvement Program database was queried for patients undergoing arthroscopic RCR between 2006 and 2016. The mFI-5, a 5-factor score comprising comorbid diabetes, hypertension, congestive heart failure, chronic obstructive pulmonary disease, and functional status limiting independence, was calculated for each patient. Multivariate logistic regression models were used to evaluate the mFI-5 score as a predictor for complications including medical complications, surgical-site infections, hospital admission, discharge to a facility, and mortality. RESULTS: In total, 24,477 patients met criteria for inclusion. The mFI-5 was a strong predictor for medical complications (P < .001), hospital admission (P < .001), length of stay (P = .007), and discharge to a facility (P = .001) but not surgical-site infections (P = .153). For each point increase in mFI-5 score, the risk for a medical complication increased by 66%, readmission by 52%, and adverse discharge by 45%. However, of all the measured complications, the mFI-5 was the strongest predictor for mortality, with the risk more than doubling for each increase in mFI-5 point (odds ratio 2.66, P = .025). CONCLUSIONS: The mFI-5 is a sensitive tool for predicting life-threatening medical complications, hospital admission, increased length of stay, adverse discharge, and mortality following arthroscopic RCR. The 5 comorbidities comprising the mFI-5 are easily obtained through the patient history, making it a practical clinical tool for identifying high-risk patients, informing preoperative counseling, and improving value-based health care. LEVEL OF EVIDENCE: Level III, prognostic.

A propensity-score matched analysis of limb salvage vs amputation for osteosarcoma.

BACKGROUND AND OBJECTIVES: With recent advances in chemotherapy and surgical techniques, the trend in the treatment of osteosarcoma continues to progress towards limb salvage. However, studies comparing limb salvage with amputation continue to be limited by selection bias and small sample sizes. This study utilized propensity-score matching to minimize potential confounders and selection bias to compare the survival rates in patients with osteosarcoma that were treated with amputation vs limb salvage surgery. METHODS: The Surveillance, Epidemiology, and End Results Program was utilized to identify all patients with a diagnosis of extremity osteosarcoma. Patients were matched with demographics, tumor characteristics, and treatment information. These variables were then fitted in a multivariate model and hazard ratios (HR) for overall- and disease-specific mortality was calculated. RESULTS: A total of 4107 patients were identified, of which, 1538 were left after propensity-score matching. Older age, Black race, upper extremity location, and higher American joint committee on cancer (AJCC) class were associated with worse overall- and disease-specific mortality rates (P ≤ .0389). Compared with their matched counterparts, patients treated with amputation had higher overall mortality (HR 1.677; P < .0001) and higher disease-specific mortality (HR 1.678; P < .0001). CONCLUSION: Patients whose tumor characteristics preclude limb salvage have significantly higher overall- and disease-specific mortality rates.

Modified frailty index predicts medical complications, length of stay, readmission, and mortality following total shoulder arthroplasty.

HYPOTHESIS: The purpose of this study was to evaluate the 5-factor modified frailty index (mFI-5) as a predictor of postoperative complications in patients undergoing total shoulder arthroplasty (TSA). METHODS: We conducted a retrospective analysis of the National Surgical Quality Improvement Program database for patients undergoing TSA between the years 2005 and 2017. The mFI-5 score, which includes the presence of comorbid diabetes, hypertension, congestive heart failure, chronic obstructive pulmonary disease, and functional status, was calculated for each patient. Multivariate logistic regression models were used to assess the relationship between the mFI-5 and postoperative complications. RESULTS: A total of 18,957 patients undergoing TSA were identified. The mFI-5 was a strong predictor of serious medical complications (cardiac arrest, myocardial infarction, septic shock, pulmonary embolism, postoperative dialysis, reintubation, and prolonged ventilator requirement), discharge to a facility, and readmission (odds ratio ≥ 1.309, P ≤ .001). Length of stay also increased as the mFI-5 score increased (P < .001). However, among all the measured complications, the mFI-5 was the strongest predictor of mortality, with the risk more than doubling for each point increase in the mFI-5 score (odds ratio, 2.113; 95% confidence interval, 1.447-3.086; P < .001). CONCLUSION: The mFI-5 predicts serious medical complications, increased length of stay, discharge to a facility, hospital readmission, and mortality in patients undergoing TSA. All of the variables within the mFI-5 are easily obtained through the patient history, allowing for a practical clinical tool that hospitals and surgeons can use to identify high-risk surgical candidates, inform preoperative counseling, and guide perioperative care to optimize patient outcomes.

Insulin Dependence Is Associated With Increased Medical Complications and Mortality After Shoulder Arthroscopy.

PURPOSE: To compare complications after shoulder arthroscopy in patients with insulin-dependent diabetes mellitus (IDDM), patients with non-insulin-dependent diabetes mellitus (NIDDM), and nondiabetic patients. METHODS: A retrospective analysis of the American College of Surgeons National Surgical Quality Improvement Program database for the years 2005 to 2016 was conducted. Logistic regression analyses were used to assess the relation between diabetic status (nondiabetic patients, n = 50,626; NIDDM patients, n = 5,332; and IDDM patients, n = 2,484) and outcomes. Multivariate models were established to adjust for age, sex, body mass index, hypertension, congestive heart failure, chronic obstructive pulmonary disease, smoking status, American Society of Anesthesiologists classification, and functional status. RESULTS: Patients with IDDM were at a higher risk of medical complications, with an adjusted odds ratio (AOR) of 1.524 (95% confidence interval [CI], 1.082-2.147), including pulmonary complications (AOR, 2.078; 95% CI, 1.089-3.964) and urinary tract infections (AOR, 2.129; 95% CI, 1.027-4.415). Patients with IDDM also had a higher risk of 30-day hospital admission (AOR, 1.581; 95% CI, 1.153-2.169) and 30-day mortality (AOR, 3.821; 95% CI, 1.243-11.750). Conversely, patients with NIDDM had comparable risks of medical and surgical complications, unplanned hospital admission, and death to nondiabetic patients. CONCLUSIONS: Medical complications, 30-day hospital admission, and death after shoulder arthroscopy were more likely in patients with IDDM. These risks diminished among patients with NIDDM, with their risks being comparable with those of nondiabetic patients. LEVEL OF EVIDENCE: Level III, retrospective comparison study.

Frailty Predicts Medical Complications, Length of Stay, Readmission, and Mortality in Revision Hip and Knee Arthroplasty.

BACKGROUND: The purpose of this study is to evaluate the 5-factor modified frailty index (mFI-5) as a predictor of postoperative complications, readmission, and mortality in patients undergoing revision hip and knee arthroplasty. METHODS: A retrospective analysis of the American College of Surgeon's National Surgical Quality Improvement Program's database for patients undergoing revision total hip arthroplasty (rTHA) and revision total knee arthroplasty (rTKA) between the years 2005 and 2016 was conducted. The 5-factor score, which includes presence of comorbid diabetes, hypertension, congestive heart failure, chronic obstructive pulmonary disease, and functional status, was calculated for each patient. Multivariate logistic regression models were used to assess the relationship between the mFI-5 and postoperative complications while controlling for demographic variables. RESULTS: In total, 13,948 patients undergoing rTHA and 16,304 patients undergoing rTKA were identified. The mFI-5 was a strong predictor of serious medical complications (cardiac arrest, myocardial infarction, septic shock, pulmonary embolism, postoperative dialysis, reintubation, and prolonged ventilator requirement), discharge to a facility, total length of stay, readmission, and mortality (P ≤ .007). CONCLUSION: The mFI-5 predicts serious medical complications, increased length of stay, discharge to a facility, hospital readmission, and mortality in patients undergoing rTHA and rTKA. All the variables within the mFI-5 are easily obtained through the patient history, allowing for a practical clinical tool that hospitals and physicians can use to identify at-risk patients, educate and engage patients and their families in a shared decision-making conversation, and guide perioperative care in order to optimize patient outcomes. LEVEL OF EVIDENCE: III.

New Five-Factor Modified Frailty Index Predicts Morbidity and Mortality in Geriatric Hip Fractures.

INTRODUCTION: Although the 11-factor modified frailty index (mFI-11) has been shown to predict adverse outcomes in elderly patients undergoing surgery for hip fractures, the newer 5-factor index has not been evaluated in this population. The goal of this study is to evaluate the mFI-5 as a predictor of morbidity and mortality in elderly patients undergoing surgical management for hip fractures. METHODS: The NSQIP database was queried for patients 60 years of age and older who underwent surgical management for hip fractures between 2005 and 2016. The 5-factor score, which comprised diabetic status, history of COPD or current pneumonia, congestive heart failure, hypertension requiring medication, and nonindependent functional status, was calculated for each patient. Multivariate logistic regression models were used to assess the relationship between the mFI-5 and 30-day postoperative complications. RESULTS: A total of 58,603 patients were identified. After adjusting for comorbidities, the mFI-5 was a strong predictor for total complications, serious medical complications (cardiac arrest, myocardial infarction, septic shock, pulmonary embolism, postoperative dialysis, reintubation, and prolonged ventilator requirement), surgical site infections, readmission, extended hospital length of stay, and mortality (P ≤ 0.008). For each point increase, the risk for any complication increased by 29.8%, serious medical complications 35.4%, surgical site infections 14.7%, readmission 24.6%, and mortality 33.7%. CONCLUSIONS: The mFI-5 is an independent predictor of postoperative morbidity and mortality in elderly patients undergoing surgery for hip fractures. This clinical tool can be used by hospitals and surgeons to identify high-risk patients, accurately council patients and families with transparency, and guide perioperative care to optimize patient outcomes. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Endoplasmic Reticulum Stress Contributes to Mitochondrial Exhaustion of CD8+ T Cells.

Tumor antigen-specific T cells rapidly lose energy and effector function in tumors. The cellular mechanisms by which energy loss and inhibition of effector function occur in tumor-infiltrating lymphocytes (TILs) are ill-defined, and methods to identify tumor antigen-specific TILs that experience such stress are unknown. Processes upstream of the mitochondria guide cell-intrinsic energy depletion. We hypothesized that a mechanism of T-cell-intrinsic energy consumption was the process of oxidative protein folding and disulfide bond formation that takes place in the endoplasmic reticulum (ER) guided by protein kinase R-like endoplasmic reticulum kinase (PERK) and downstream PERK axis target ER oxidoreductase 1 (ERO1α). To test this hypothesis, we created TCR transgenic mice with a T-cell-specific PERK gene deletion (OT1 + Lckcre+ PERK f/f , PERK KO). We found that PERK KO and T cells that were pharmacologically inhibited by PERK or ERO1α maintained reserve energy and exhibited a protein profile consistent with reduced oxidative stress. These T-cell groups displayed superior tumor control compared with T effectors. We identified a biomarker of ER-induced mitochondrial exhaustion in T cells as mitochondrial reactive oxygen species (mtROS), and found that PD-1+ tumor antigen-specific CD8+ TILs express mtROS. In vivo treatment with a PERK inhibitor abrogated mtROS in PD-1+ CD8+ TILs and bolstered CD8+ TIL viability. Combination therapy enabled 100% survival and 71% tumor clearance in a sarcoma mouse model. Our data identify the ER as a regulator of T-cell energetics and indicate that ER elements are effective targets to improve cancer immunotherapy.

New 5-Factor Modified Frailty Index Predicts Morbidity and Mortality in Primary Hip and Knee Arthroplasty.

BACKGROUND: While the 11-factor modified frailty index (mFI) has been shown to predict adverse outcomes in patients undergoing total joint arthroplasty, the 5-factor index has not been evaluated in this patient population. The goal of this study was to evaluate the utility of the mFI-5 as a predictor of morbidity and mortality in patients undergoing primary total hip and knee arthroplasty. METHODS: A retrospective analysis of the American College of Surgeons National Surgical Quality Improvement Program's database for patients undergoing total hip arthroplasty and total knee arthroplasty between the years 2005 and 2016 was conducted. The 5-factor score, which includes the presence of comorbid diabetes, hypertension, congestive heart failure, chronic obstructive pulmonary disease, and functional status, was calculated for each patient. Multivariate logistic regression models were used to assess the relationship between the mFI-5 and postoperative complications while controlling for demographic variables. RESULTS: One hundred forty thousand one hundred fifty-eight patients undergoing total hip arthroplasty and 226,398 patients undergoing total knee arthroplasty were identified. After adjusting for demographic variables and comorbid conditions, logistic regression analyses revealed that the mFI-5 was a strong predictor for total complications, Clavien-Dindo grade IV complications (cardiac arrest, myocardial infarction, septic shock, pulmonary embolism, postoperative dialysis, reintubation, and prolonged ventilator requirement), surgical site infections, readmission, and 30-day mortality (P < .001). CONCLUSIONS: The mFI-5 is an independent predictor of postoperative complications including life-threatening medical complications, surgical site infections, hospital readmission, and 30-day mortality after primary hip and knee arthroplasty. This clinical tool can be used to identify high-risk surgical patients and guide preoperative counseling to optimize outcomes. LEVEL OF EVIDENCE: III.

Arthroscopically-Guided, Cannulated, Headless Compression Screw Fixation of the Symptomatic Os Acromiale.

Os acromiale is a failure of fusion between 1 or more ossification centers of the scapula and the acromion process. Pain can be caused by motion and impingement of the unfused segment. Several methods for the management of os acromiale have been described. Internal fixation is the most common surgical technique, followed by excision and acromioplasty. We present a novel technique for treatment of symptomatic os acromiale using arthroscopically-guided headless compression screws. This is a viable technique in the management of symptomatic os acromiale due to preservation of the periosteal blood supply and less concern for symptomatic hardware.

The clinical implications of heterotopic ossification in patients treated with radial head replacement for trauma: A case series and review of the literature.

Radial head arthroplasty (RHA) is an acceptable treatment for comminuted radial head fractures (RHF). Fourteen patients with no postop HO prophylaxis were treated with RHA for comminuted RHF. A 50% incidence in HO was seen following RHA with a statistically increased risk (p ≤ 0.05) of reoperation compared to those without HO. Decreased ROM was seen on the affected side (p ≤ 0.05); patients without HO showed no statistical difference (p ≥ 0.05) in ROM or grip strength. HO following RHA increases patient risk for reoperation and decreases ROM. We recommend HO prophylaxis with NSAIDs and/or radiotherapy if no direct patient contraindications are found.

The impact of race on the development of severe heterotopic ossification following acetabular fracture surgery.

OBJECTIVES: To determine the association between race on severe heterotopic ossification (HO) following acetabular fracture surgery. DESIGN: Retrospective case control study. SETTING: Level I university trauma centre. METHODS: Two hundred and fifty-three patients who were surgically treated for acetabular fractures were retrospectively evaluated. Postoperative radiographs were evaluated for HO by a blinded musculoskeletal radiologist, and classified based on a modified Brooker classification. RESULTS: Of the 253 patients that met inclusion and exclusion criteria, 175 (69%) were male and 78 (31%) were female. One hundred and fifty-four (61%) patients were Caucasian, and 99 (39%) were African American (AA). Fifty-five (21%) patients developed severe HO. Of those who developed severe HO, 25 were Caucasian (45%), 30 were African American (55%). Forty-one patients (75%) with severe HO were male, and 14 (25%) were female. No statistical differences (p>0.05) were found between groups in terms of age, days to surgery, GCS at presentation, surgical approach, perioperative HO prophylaxis, or AO/OTA fracture classification. The patient population was then stratified by race, gender, and race/gender. AA were more likely than Caucasians to develop severe HO (odds ratio [OR], 2.24; confidence interval [CI], 1.22-4.11). When gender was considered independent of race, no statistical differences (p>0.05) were observed (OR, 1.40; CI, 0.71-2.75). AA males were much more likely to develop severe HO when compared to Caucasian females (OR, 4.4; CI, 1.38-14.06). CONCLUSION: Race is associated with different rates of severe HO formation following acetabular fracture surgery. AA patients are significantly more likely to develop severe HO following acetabular fracture surgery when compared to Caucasian patients.

Bronchogenic squamous cell carcinoma with soft-tissue metastasis to the hand: an unusual case presentation and review of the literature.

Carcinoma of the lung is the most common lethal form of cancer in both men and women worldwide. Orthopedic manifestations of lung cancer frequently include bony metastasis, most commonly the vertebrae (42%), ribs (20%), and pelvis (18%). Acral metastatic disease is defined as metastasis distal to the elbow or the knee. Metastases to the bones of the hand are extremely rare. Only 0.1% of metastatic disease resulting from any type of carcinoma or sarcoma manifests as metastasis in the hand. There are only a few reports in the literature of soft-tissue or muscular metastasis to the hand from a carcinoma. Of these cases, the majority are caused by metastatic lung carcinoma. However, there are no reports in the literature of metastatic disease of squamous cell origin affecting the soft tissues of the hand. We present a case of a man with known metastatic squamous cell carcinoma of the lung who presented with acral soft-tissue metastatic disease. This report highlights a rare clinical scenario that has not been reported in the literature. This report also highlights a rare but important consideration for clinicians who encounter acral soft-tissue lesions in patients with a history of a primary carcinoma.

Absence of decussation of the superior cerebellar peduncles in patients with Joubert syndrome.

Joubert syndrome (JS) is characterized by absence of decussation of both corticospinal tracts and superior cerebellar peduncles (SCP). Our hypothesis was that evidence for absence of SCP decussation may be found on routine brain MRI studies. Midsagittal T1-weighted images from 20 JS patients and 30 age-matched controls were retrospectively reviewed. An ill-defined area of lower T1 signal in the inferior midbrain was considered the sign of SCP decussation, and its presence or absence was noted. Fractional anisotropy (FA) maps were obtained in three JS patients and four controls. The SCP decussation was not visualized in any subject under 30 months of age. In subjects above 30 months of age the sign of the SCP decussation was absent in all 6 JS patients and present in all 16 controls. FA maps confirmed the absence of the SCP decussation in the JS patients. The SCP decussation is well seen on routine brain MRI studies in controls older than 30 months of age and absent in all JS patients, confirming the proposed lack of commissural fibers in JS, and accounting in part for the molar tooth sign.