Long-Term Outcomes of Biceps Rerouting for Flexible Supination Contractures in Children With Brachial Plexus Birth Injuries.

PURPOSE: Forearm supination contractures occur in 7% of children with brachial plexus birth injuries (BPBI). Biceps rerouting is proposed when pronation has deteriorated but is passively correctable to at least 0° (neutral). The purpose of this investigation was to evaluate long-term outcomes of biceps rerouting for this indication, including magnitude and maintenance of correction, complications, and subsequent osteotomy. METHODS: We conducted a retrospective review of all children with BPBI and forearm supination contractures treated with biceps rerouting alone, for the above indications, from 1993 to 2017 with at least 2 years follow-up. Demographic information, BPBI characteristics, surgical details, and ranges of motion were obtained from medical records. Pre- and postoperative active pronation (AP) and supination (AS), elbow flexion contracture, and arc of forearm rotation (Arc) were analyzed using linear mixed-effect models. RESULTS: Twenty-five children (13 females; 13 left forearms; 15 global BPBI) underwent biceps rerouting at age 7 ± 3 years and were followed for 6 ± 3 years. Before surgery, the mean AP and AS were 6° ± 29° and 62° ± 27°, respectively. At the final follow-up, the mean AP, AS, and Arc were 39° ± 36°, 18° ± 34°, and 57° ± 42°, respectively. AP was significantly improved and AS was significantly decreased by 2 years after surgery and at the final follow-up. Neither Arc nor elbow flexion contracture changed significantly. Two of 25 (8%) children underwent subsequent forearm osteotomy. CONCLUSIONS: Biceps rerouting in children with BPBI improves the forearm position when pronation is deteriorating by shifting the arc from supination to pronation without decreasing the arc of motion or worsening elbow flexion contractures. There is a low risk of complications and a limited need for subsequent forearm osteotomy. These results are maintained over time. When performed before passive pronation is reduced beyond neutral, this procedure may prevent severe supination contractures and reduce the need for forearm osteotomy. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Trends in demographics, charges, and outcomes of patients undergoing excision of sporadic vestibular schwannoma.

OBJECTIVE: To assess demographics, charges, and outcome measures by temporal and volume analysis in the treatment of vestibular schwannoma. DESIGN: Cross-sectional analysis. SETTING, SUBJECTS, AND METHODS: The California Hospital Inpatient Discharge Databases from 1996 to 2010. RESULTS: A total of 6545 cases from 1996 to 2010 were identified. Of these, 86.2% occurred at high-volume centers (HVCs), and the number of annual cases decreased by 28.5%. Patients presenting for surgery were increasingly younger, non-Caucasian, and likely to have comorbidities. Total charges significantly increased over time (P < .001), with the median total charge in 2006-2010 being $91,338 compared with $38,607.92 in 1996-2000 after adjusting for inflation. Routine discharges (home or residence) were more likely at HVCs (odds ratio [OR] 5.48, P < .001) and less likely if patients had Medicaid (Medi-Cal; OR 0.51, P = .002) or Medicare (OR 0.55, P = .022), were 65 years or older (OR 0.56, P = .025), or had comorbidities (OR 0.54, P < .001). Shorter hospital stays were more likely at HVCs (OR 3.77, P < .001) and less likely if patients had Medicaid (OR 0.36, P < .001) or comorbidities (OR 0.61, P < .001). Lesser total charges were more likely at HVCs (OR 2.12, P = .002) and less likely if patients had comorbidities (OR 0.70, P < .001). Mortality was less likely at HVCs (OR 0.10, P = .011). CONCLUSION: The profile of patients undergoing vestibular neuroma excision is changing. Surgical volume is decreasing, suggesting a trend toward more conservative management or stereotactic radiation. Patients are best served at HVCs, where routine discharges, shorter length of stay, decreased mortality, and lower total charges are more likely.

Potassium channel modulation by a toxin domain in matrix metalloprotease 23.

Peptide toxins found in a wide array of venoms block K(+) channels, causing profound physiological and pathological effects. Here we describe the first functional K(+) channel-blocking toxin domain in a mammalian protein. MMP23 (matrix metalloprotease 23) contains a domain (MMP23(TxD)) that is evolutionarily related to peptide toxins from sea anemones. MMP23(TxD) shows close structural similarity to the sea anemone toxins BgK and ShK. Moreover, this domain blocks K(+) channels in the nanomolar to low micromolar range (Kv1.6 > Kv1.3 > Kv1.1 = Kv3.2 > Kv1.4, in decreasing order of potency) while sparing other K(+) channels (Kv1.2, Kv1.5, Kv1.7, and KCa3.1). Full-length MMP23 suppresses K(+) channels by co-localizing with and trapping MMP23(TxD)-sensitive channels in the ER. Our results provide clues to the structure and function of the vast family of proteins that contain domains related to sea anemone toxins. Evolutionary pressure to maintain a channel-modulatory function may contribute to the conservation of this domain throughout the plant and animal kingdoms.