Infraspinatus and deltoid length and patient height: implications for lateralization and distalization in reverse total shoulder arthroplasty.

BACKGROUND: Restoration of muscular strength is predicated on restoration of muscle length. The purpose of this study was to describe infraspinatus and deltoid length preoperative to reverse total shoulder arthroplasty (RTSA) to guide distalization and lateralization to restore preoperative muscle length. METHODS: This was a retrospective radiographic study. We measured the infraspinatus length on preoperative computed tomographic images and the deltoid length on preoperative radiographs. For all measurements, reliability was first established by comparing measurements between 2 observers, and intraclass correlation coefficients (ICCs) were calculated. We then calculated descriptive statistics for these muscle lengths and developed a formula to predict these muscle lengths from patient demographics. RESULTS: We measured infraspinatus length in 97 patients and deltoid length in 108 patients. Inter-rater reliability was excellent, with all ICCs >0.886. The mean infraspinatus length was 15.5 cm (standard deviation 1.3) and ranged from 12.6-18.9 cm, whereas the deltoid length was 16.2±1.7 cm and ranged from 12.5-20.2 cm. Both infraspinatus (r = 0.775, P < .001) and deltoid length (r = 0.717, P < .001) were highly correlated with patient height but did not differ between diagnoses. Formulae developed through linear regression allowed prediction of muscle length to within 1 cm in 78% and within 2 cm in 100% for the infraspinatus and 60% and 88% for the deltoid. CONCLUSION: Deltoid and infraspinatus length are variable but highly correlated with patient height. To maintain tension, 2 mm of lateralization and distalization should be added for every 6 inches (∼15 cm) of height above average for a Grammont-style RTSA.

Cerebellar mutism after posterior fossa tumor resection in children: a multicenter international retrospective study to determine possible modifiable factors.

PURPOSE: A preliminary survey of pediatric neurosurgeons working at different centers around the world suggested differences in clinical practice resulting in variation in the risk of pediatric cerebellar mutism (CM) and cerebellar mutism syndrome (CMS) after posterior fossa (PF) tumor resection. The purposes of this study were (1) to determine the incidence and severity of CM and CMS after midline PF tumor resection in children treated at these centers and (2) to identify potentially modifiable factors related to surgical management (rather than tumor biology) that correlate with the incidence of CM/CMS. METHODS: Attending pediatric neurosurgeons at British Columbia's Children's Hospital (BCCH) and neurosurgeons who completed a pediatric neurosurgery fellowship at BCCH were invited to provide data from the center where they currently practiced. Children aged from birth to less than 18 years who underwent initial midline PF tumor resection within a contemporary, center-selected 2-year period were included. Data was obtained by retrospective chart and imaging review. Modifiable surgical factors that were assessed included pre-resection surgical hydrocephalus treatment, surgical positioning, ultrasonic aspirator use, intraoperative external ventricular drain (EVD) use, surgical access route to the tumor, and extent of resection. CM was defined as decreased or absent speech output postoperatively and CMS as CM plus new or worsened irritability. RESULTS: There were 263 patients from 11 centers in 6 countries (Canada, Germany, the Netherlands, India, Indonesia, and the USA). Median age at surgery was 6 years (range < 1 to 17 years). The overall incidence of postoperative CM was 23.5% (range 14.7-47.6% for centers with data on ≥ 20 patients). The overall incidence of CMS was 6.5% (range 0-10.3% for centers contributing data on ≥ 20 patients). A multivariate logistic regression on the full data set showed no significant association between pre-resection surgical hydrocephalus treatment, prone position, ultrasonic aspirator use, EVD use, telovelar approach, complete or near total resection, or treating center and either postoperative CM or CMS. CONCLUSIONS: While there was variation in surgical management of midline PF tumors among centers participating in this study, the factors in management that were examined did not predict postoperative CM or CMS.

Effects of ganciclovir treatment in a murine model of cytomegalovirus-induced hearing loss.

OBJECTIVE: To determine whether ganciclovir (GCV) treatment reduces sensorineural hearing loss in cytomegalovirus (CMV)-infected mice. The effects of GCV on viral load, absolute neutrophil count (ANC), and outer hair cell (OHC) integrity were also investigated. METHODS: Infected BALB/c mice were inoculated with murine CMV on postnatal day 3. Those treated with GCV received an intraperitoneal injection twice a day for 14 days. Auditory thresholds were assessed using distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) testing 4 weeks after inoculation. Temporal bones were used for determination of viral load by quantitative polymerase chain reaction and hair cell quantification by scanning electron microscopy. ANCs were completed by an automated hematology analyzer, with manual review for confirmation. RESULTS: GCV-treated CMV-infected mice had lower ABR (P < 0.0001, Kruskal-Wallis test) and DPOAE (P < 0.0001) thresholds compared to CMV-infected untreated mice, indicating that GCV protected mice from CMV-induced hearing loss. Viral load in infected populations undergoing GCV treatment was significantly decreased (P = 0.03) relative to untreated mice. GCV treatment alone had no effect on ABR and DPOAE compared to untreated, uninfected controls (P = 0.1, P = 0.24, respectively). GCV-treated mice received increased protection from OHC loss when compared to untreated groups, with total OHC losses of approximately 7% and 14%, respectively (P < 0.05). Neutropenia was absent after 7 days of GCV treatment. CONCLUSION: Ganciclovir effectively ameliorated SNHL and partially protected from OHC loss in a preclinical model of congenital CMV infection, seemingly by reducing viral load. LEVEL OF EVIDENCE: NA Laryngoscope, 130:1064-1069, 2020.