Diagnosis and Management of Constitutional Mismatch Repair Deficiency Syndrome.

Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare autosomal recessive genetic disorder that has little more than 200 total cases reported as of 2020. Whereas a single mutation in genes responsible for mismatch repair causes the autosomal dominant Lynch syndrome (LS), CMMRD is caused by biallelic heterozygous defects: distinct deleterious mutations on each allele for a single gene. As the disease is exceedingly rare and may present via a wide variety of signs, including neurofibromatosis type 1- and Lynch Syndrome-associated malignancies, diagnosis and subsequent surveillance are complex with suggested methods published by the International Replication Repair Deficiency Consortium. We report here the history and management of a patient whose newly diagnosed CMMRD was managed with both curative and prophylactic surgical treatment.

Utility of dual energy computed tomography in the evaluation of infiltrative skeletal lesions and metastasis: a literature review.

Computed tomography (CT) is routinely used to diagnose and evaluate metastatic lesions in oncology. CT alone suffers from lack of sensitivity, especially for skeletal lesions in the bone marrow and lesions that have similar attenuation profiles to surrounding bone. Magnetic resonance imaging and nuclear medicine imaging remain the gold standard in evaluating skeletal lesions. However, compared to CT, these modalities are not as widely available or suitable for all patients. Dual energy computed tomography (DECT) exploits variations in linear attenuation coefficient of materials at different photon energy levels to reconstruct images based on material composition. DECT in musculoskeletal imaging is used in the imaging of crystal arthropathy and detecting subtle fractures, but it is not broadly utilized in evaluating infiltrative skeletal lesions. Malignant skeletal lesions have different tissue and molecular compositions compared to normal bone. DECT may exploit these physical differences to delineate infiltrative skeletal lesions from surrounding bone better than conventional monoenergetic CT. Studies so far have examined the utility of DECT in evaluating skeletal metastases, multiple myeloma lesions, pathologic fractures, and performing image-guided biopsies with promising results. These studies were mostly retrospective analyses and case reports containing small samples sizes. As DECT becomes more widely used clinically and more scientific studies evaluating the performance of DECT are published, DECT may eventually become an important modality in the work-up of infiltrative skeletal lesions. It may even challenge MRI and nuclear medicine because of relatively faster scanning times and ease of access.

Comparing clinical outcomes between rotator cuff repairs, SLAP repairs, and combined repairs.

BACKGROUND: Superior labrum lesion from anterior to posterior (SLAP) often presents together with other shoulder pathologies such as rotator cuff tear (RCT), but it is uncertain if repairing both SLAP and RCT has superior clinical outcomes over isolated repairs of SLAP and RCT. MATERIALS AND METHODS: This was a retrospective cohort study with prospectively collected data, reviewing 157 patients who underwent arthroscopic repair of either RCT, SLAP (type II lesion), or both. Before surgery and after 6 weeks, 12 weeks, and 24 weeks, shoulder objective range of motion and strength were measured, patient-reported function and pain was assessed by the modified L'Insalata questionnaire with a Likert scale, and complications after each repair were examined. RESULTS: At 24 weeks after surgery, the combined group (n = 22) and SLAP group (n = 47) had significantly higher forward flexion (165° ± 4° and 167° ± 4° vs. 154° ± 3°, P = .01 and P = .01), external rotation strength (82 ± 6 N, 81 ± 6 N vs. 61 ± 3 N, P = .01 and P = .01), and abduction strength (94 ± 14 N, 78 ± 8 N vs. 53 ± 3 N, P = .001 and P = .02) compared with the rotator cuff tear repair (RCR) group (n = 88). The combined group also had stronger internal rotation than the RCR group (107 ± 12 N vs. 72 ± 4 N, P = .02). Function and pain improved from "severe-moderate" to "moderate-mild" in all groups after surgery. CONCLUSION: Repairing RCT and SLAP tears together results in significant clinical benefits compared to repairing just RCT and analogous results against SLAP-only repair.

Investigating the nasal cycle using unilateral peak nasal inspiratory flow and acoustic rhinometry minimal cross-sectional area measurements.

OBJECTIVE: To plot the nasal cycle using unilateral peak nasal inspiratory flow (UPNIF) and unilateral minimal cross-sectional area (UMCA) readings demonstrating a linear relationship in normal nasal function. Additionally, to determine how this changes in abnormal nasal function. DESIGN: A cross-sectional study measuring UPNIF and UMCA in controls demonstrating normal nasal function and in patients with nasal obstruction. SETTING: Royal National Throat Nose and Ear Hospital, London. PARTICIPANTS: A total of 39 participants, 26 controls and 13 patients, were recruited. Controls exhibited normal nasal function with SNOT-22 <5. Patients nasal obstruction symptoms secondary to inflammation or structural abnormality with SNOT-22 >9. MAIN OUTCOME MEASURES AND RESULTS: Airflow rates and resistance values were derived from UPNIF and UMCA measurements respectively based on Poiseuille's laws. Ratios between right and left UPNIF and UMCA values were taken to adjust for confounding factors. The relationship of 1/Resistance Ratio and Airflow Rate Ratio demonstrated a linear of direct proportionality of strong correlation and statistical significance (correlation coefficient = 0.76, P « 0.01). This suggests that data points from controls with a normal nasal cycle lie closely along the regressed line, whilst those lying significantly away were shown to belong to patients with nasal dysfunction. Olfactory dysfunction appears to be a sensitive discriminator in predicting this. CONCLUSION: This study demonstrates the directly proportional relationship of 1/Resistance Ratio and Airflow Rate Ratio in normal nasal function. Furthermore, nasal pathology can be predicted if data points lie significantly outside these normal limits. Further studies are needed to validate exact normal and abnormal thresholds.

Preventing brachial plexus injury during shoulder surgery: a real-time cadaveric study.

BACKGROUND: Brachial plexopathy is not uncommon after shoulder surgery. Although thought to be due to stretch neuropathy, its etiology is poorly understood. This study aimed to identify arm positions and maneuvers that may risk causing brachial plexopathy during shoulder arthroplasty. METHODS: Tensions in the cords of the brachial plexuses of 6 human cadaveric upper limbs were measured using load cells while each limb was placed in different arm positions and while they underwent shoulder hemiarthroplasty and revision reverse arthroplasty. Arthroplasty procedures in 4 specimens were performed with standard limb positioning (unsupported), and 2 specimens were supported from under the elbow (supported). Each cord then underwent biomechanical testing to identify tension corresponding to 10% strain (the stretch neuropathy threshold in animal models). RESULTS: Tensions exceeding 15 N, 11 N, and 9 N in the lateral, medial, and posterior cords, respectively, produced 10% strain. Shoulder abduction >70° and combined external rotation >60° with extension >50° increased medial cord tension above the 10% strain threshold. Medial cord tensions (mean ± standard error of the mean) in unsupported specimens increased over baseline during hemiarthroplasty (sounder insertion [4.7 ± 0.6 N, P = .04], prosthesis impaction [6.1 ± 0.8 N, P = .04], and arthroplasty reduction [5.0 ± 0.7 N, P = .04]) and revision reverse arthroplasty (retractor positioning [7.2 ± 0.8 N, P = .02]). Supported specimens experienced lower tensions than unsupported specimens. CONCLUSIONS: Shoulder abduction >70°, combined external rotation >60° with extension >50°, and downward forces on the humeral shaft may risk causing brachial plexopathy. Retractor placement, sounder insertion, humeral prosthesis impaction, and arthroplasty reduction increase medial cord tensions during shoulder arthroplasty. Supporting the arm from under the elbow protected the brachial plexus in this cadaveric model.

The effect of concomitant glenohumeral joint capsule release during rotator cuff repair--a comparative study.

BACKGROUND: There is debate as to whether to operate or to defer surgery on patients with concomitant rotator cuff tear and shoulder stiffness. The purpose of this study was therefore to compare the outcomes in those patients who had both their rotator cuff tear and shoulder stiffness treated with the outcomes of patients who had a rotator cuff repair but no stiffness. METHODS: Twenty-five patients formed the stiffness group (receiving a concomitant rotator cuff repair and manipulation under anesthesia ± arthroscopic capsular release for preoperative ipsilateral stiffness), and a chronologically matched group of 170 rotator cuff repair-only patients formed the nonstiffness group. Patients ranked their pain and function scores preoperatively and at 1 week, 6 weeks, 12 weeks, 6 months, and 2 years postoperatively; examiners recorded range of motion, strength, and presence of impingement signs. Repair integrity was determined using ultrasound. RESULTS: Patients from both groups had significantly improved clinical outcomes at the 2-year follow-up compared with preoperative values. Range of motion was similar between groups at 2 years for forward flexion, abduction, and external rotation, whereas the nonstiffness group had a superior range of internal rotation (P = .014). Stiffness patients had 0 of 25 (0%) retears at 2 years compared with 34 of 170 (20%) in the nonstiffness group (P = .009). CONCLUSIONS: The good outcomes of rotator cuff repair with glenohumeral capsular release disproved our hypothesis and suggest that there is no advantage in delaying repair of a rotator cuff tear to allow stiffness to resolve and that stiffness confers an advantage in terms of repair integrity. LEVEL OF EVIDENCE: Level III; Retrospective Cohort Design; Treatment Study.

Trauma versus no trauma: an analysis of the effect of tear mechanism on tendon healing in 1300 consecutive patients after arthroscopic rotator cuff repair.

BACKGROUND: Patients with rotator cuff tears often recall a specific initiating event (traumatic), whereas many cannot (nontraumatic). It is unclear how important a history of trauma is to the outcomes of rotator cuff repair. METHODS: This question was addressed in a study cohort of 1300 consecutive patients who completed a preoperative questionnaire regarding their shoulder injury and had a systematic evaluation of shoulder range of motion and strength, a primary arthroscopic rotator cuff repair performed by a single surgeon, an ultrasound scan, and the same subjective and objective measurements made of their shoulder 6 months after surgery. Post hoc, this cohort was separated into 2 groups: those who reported no history of trauma on presentation (n = 489) and those with a history of traumatic injury (n = 811). RESULTS: The retear rate in the group with no history of trauma was 12%, whereas that of the group with a history of trauma was 14% (P = .36). Those patients with a history of shoulder trauma who waited longer than 24 months had higher retear rates (20%) than those who had their surgery earlier (13%) (P = .040). CONCLUSION: Recollection of a traumatic initiating event had little effect on the outcome of arthroscopic rotator cuff repair. Duration of symptoms was important in predicting retears if patients recalled a specific initiating event but not in patients who did not recall any specific initiating event. Patients with a history of trauma should be encouraged to have their rotator cuff tear repaired within 2 years.