Where to position osteotomies in genioglossal advancement surgery based on locations of the mental foramen, canine, lateral incisor, central incisor, and genial tubercle.

PURPOSE: The study aimed to provide precise measurements of anterior mandibular structural anatomy and to explore potential osteotomies for genioglossal advancement. METHODS: Cone beam computed tomography was used to analyze 33 randomly selected patients undergoing surgery for obstructive sleep apnea (OSA) between 2014 and 2016 at an academic surgical hospital. The locations of relevant mandibular structures were measured and statistical modeling was performed. RESULTS: Mean horizontal distances from midline to the mental foramina and the roots of the canine, lateral incisor, and central incisor were 22.11 ± 1.92, 13.56 ± 3.01, 6.19 ± 1.58, and 2.04 ± 0.87 mm, respectively. Mean vertical distances from the inferior border of the mandible were 15.15 ± 1.77, 17.11 ± 3.28, 20.48 ± 3.10, and 21.81 ± 3.49 mm, respectively. The superior border of the genial tubercle was 15.63 ± 2.75 mm, and the inferior border was 6.87 ± 3.29, from the inferior border of the mandible. The angle of decline of the best-fit line through the important structures was about 18° from the occlusion plane at the midline. CONCLUSIONS: A straight line estimating the mental foramen, canine, lateral incisor, and central incisor tooth roots crosses at a mean of 22.3-22.6 mm above the inferior border of the mandible at the midline and has an angle of decline of about 18°. Potential osteotomies made parallel to and below this line result in tradeoffs between maximizing capture of the genioglossus muscle attachment and risk of dental/neurovascular injury.

Design comparison: manipulation after total knee arthroplasty.

Postoperative stiffness is a relatively uncommon issue in total knee arthroplasty (TKA). However, it can be a debilitating complication when it occurs. Manipulation under anesthesia (MUA) is commonly used as the primary treatment modality following failed physiotherapy. The Advance medial pivot knee (Wright Medical Technology) was created in an effort to prevent stiffness postoperatively and increase range of motion. The Evolution medial pivot knee is a second-generation design that builds on the technology of the Advance knee. This article presents a retrospective review of prospectively collected data on 881 primary medial pivot knees (592 Advance knees, 289 Evolution knees). It was theorized that the design changes made to the Evolution knees might contribute toward reducing the need for MUA. It was found that the Evolution knees required significantly fewer manipulations under anesthesia (p = .036). The design modifications made to the Evolution knees may have contributed to the lower rate of MUA.

Anatomy of the palmar branch of the ulnar nerve: application to ulnar and median nerve decompressive surgery.

OBJECT: The palmar cutaneous branch of the ulnar nerve (PCUN) has received little attention in the literature, and to the authors' knowledge, has received no attention in the neurosurgical literature. The present study was performed to help the surgeon minimize postoperative complications of nerve decompression at the wrist. METHODS: Forty cadaveric upper limbs underwent dissection of the ulnar nerve in the forearm, at the wrist, and in the palm. The PCUN was investigated and when identified, measurements were made and relationships documented between this cutaneous branch and the ulnar artery. The length and width of the PCUN were measured, as was the distance from the medial epicondyle of the humerus to the origin of the PCUN from the ulnar nerve. RESULTS: A PCUN was found on 90% of sides. The origin of the PCUN from the ulnar nerve was found to lay a mean of 14.3 cm distal to the medial epicondyle. The mean length and width of this branch were 13 and 0.08 cm, respectively. In the forearm, the PCUN traveled lateral to the ulnar artery on 75% of sides and on the medial side of this vessel on the remaining sides. The PCUN perforated the fascia of the anterior forearm just proximal to the distal wrist crease. In the palm, the PCUN traveled superficial to the superficial palmar arch on all but 5 sides, where it traveled deep to this vascular structure's distal extent. On 2 sides each, the PCUN communicated with the superficial and deep ulnar nerves. On 2 sides, the PCUN communicated with the palmar cutaneous branch of the median nerve. The majority of the terminal fibers of the PCUN were found on the ulnar side of a hypothetical line drawn longitudinally through the fourth digit and supplied an area roughly 3 × 3 cm over the proximal medial palm. CONCLUSIONS: The authors hope that the present data may be useful to the surgeon during decompressive procedures at the wrist, such as carpal tunnel and the Guyon canal. Based on this study, skin incisions of the palm made longitudinally along a line through the middle of the fourth digit would minimize injury to the PCUN.

Inducible nerve growth factor delivery for peripheral nerve regeneration in vivo.

BACKGROUND: HEK-293 cells can be genetically modified to release and regulate nerve growth factor (NGF) in vitro. The aim of this study was to evaluate the impact of this NGF delivery system on peripheral nerve regeneration in vivo. METHODS: HEK-293 cells were transfected with an ecdysone receptor, NGF cDNA, and herpes simplex virus-thymidine kinase suicide vector. NGF production is induced by ponasterone A and stopped by ganciclovir. A 13-mm sciatic nerve gap was bridged with Silastic conduits in 120 nude rats, and transfected HEK-293 cells were added, induced, and boostered to secrete bioactive NGF. RESULTS: The induction of the cell line and additional booster with ponasterone A demonstrated significantly higher levels of bioactive NGF, enhanced macroscopic nerve growth, improved functional recovery, and histologic regeneration when compared with control groups after 7, 14, and 21 days, and 2 and 4 months. The treatment with ganciclovir resulted in suppression of the NGF production and decreased functional and histologic outcomes. CONCLUSIONS: Transfected HEK-293 cells can be regulated to inducibly produce bioactive NGF in vivo over prolonged periods. This tissue-engineered nerve construct including the NGF delivery system is able to improve peripheral nerve regeneration and functional recovery and appears to be superior to nerve isografts.

Herpes simplex virus-thymidine kinase-based suicide gene therapy as a "molecular switch off" for nerve growth factor production in vitro.

Tissue-engineered constructs offer a new hope to patients suffering from functional impairment after nerve injury. An effort has been made to focus on delivery, regulation, and "molecular shutoff" of nerve growth factor (NGF) in tissue-engineered constructs. We have previously demonstrated that human embryonic kidney (HEK-293) cells can be genetically modified to secrete NGF at varying time points upon up regulation with Ponasterone A (PonA) both in vitro and in vivo. In the present study, HEK-293 cells that stably and inducibly produce NGF were further stably transfected with herpes simplex virus-thymidine kinase gene as a suicide gene (hNGF-EcR-293-TK) in order to shut off the NGF secretion and kill the cells upon treatment with ganciclovir (GCV). These cells following induction with PonA secreted NGF levels of 6659.2 +/- 489.4 pg/mL at day 10 postbooster dose at day 5, which was significantly higher than the control noninduced cells. The NGF secreted by these cells was bioactive as determined by a rat adrenal pheochromocytoma (PC-12) cell bioassay. Treatment of these cells with GCV significantly reduced the NGF levels to 645.3 +/- 16.2 pg/mL at day 10 and live cell numbers dropped to 7.95 x 10(3) +/- 278 compared to 2.73 x 10(5) +/- 6.1 x 10(4). GCV-treated cell media when transferred to the PC-12 cell bioassay demonstrated less than 10% cells differentiating into neurite-like extensions. We conclude that hNGF-EcR-293-TK cells can inducibly secrete bioactive NGF when treated with the inducing agent and can also be killed upon treatment with GCV. This double-gene transfection for gene expression and molecular shutoff mechanism will be a useful tool in tissue-engineered nerve constructs.