Restoring bladder function using motor and sensory nerve transfers: a cadaveric feasibility study.

OBJECTIVE: Bladder dysfunction after nerve injury has a variable presentation, and extent of injury determines whether the bladder is spastic or atonic. The authors have proposed a series of 3 nerve transfers for functional innervation of the detrusor muscle and external urethral sphincter, along with sensory innervation to the genital dermatome. These transfers are applicable to only cases with low spinal segment injuries (sacral nerve root function is lost) and largely preserved lumbar function. Transfer of the posterior branch of the obturator nerve to the vesical branch of the pelvic nerve provides a feasible mechanism for patients to initiate detrusor contraction by thigh adduction. External urethra innervation (motor and sensory) may be accomplished by transfer of the vastus medialis nerve to the pudendal nerve. The sensory component of the pudendal nerve to the genitalia may be further enhanced by transfer of the saphenous nerve (sensory) to the pudendal nerve. The main limitations of coapting the nerve donors to their intrapelvic targets are the bifurcation or arborization points of the parent nerve. To ensure that the donor nerves had sufficient length and diameter, the authors sought to measure these parameters. METHODS: Twenty-six pelvic and anterior thigh regions were dissected in 13 female cadavers. After the graft and donor sites were clearly exposed and the branches identified, the donor nerves were cut at suitable distal sites and then moved into the pelvis for tensionless anastomosis. Diameters were measured with calipers. RESULTS: The obturator nerve was bifurcated a mean ± SD (range) of 5.5 ± 1.7 (2.0-9.0) cm proximal to the entrance of the obturator foramen. In every cadaver, the authors were able to bring the posterior division of the obturator nerve to the vesical branch of the pelvic nerve (located internal to the ischial spine) in a tensionless manner with an excess obturator nerve length of 2.0 ± 1.2 (0.0-5.0) cm. The distance between the femoral nerve arborization and the anterior superior iliac spine was 9.3 ± 1.8 (6.5-15.0) cm, and the distance from the femoral arborization to the ischial spine was 12.9 ± 1.4 (10.0-16.0) cm. Diameters were similar between donor and recipient nerves. CONCLUSIONS: The chosen donor nerves were long enough and of sufficient caliber for the proposed nerve transfers and tensionless anastomosis.

Nerve transfer for restoration of lower motor neuron-lesioned bladder function. Part 2: correlation between histological changes and nerve evoked contractions.

We determined the effect of pelvic organ decentralization and reinnervation 1 yr later on urinary bladder histology and function. Nineteen canines underwent decentralization by bilateral transection of all coccygeal and sacral (S) spinal roots, dorsal roots of lumbar (L)7, and hypogastric nerves. After exclusions, eight were reinnervated 12 mo postdecentralization with obturator-to-pelvic and sciatic-to-pudendal nerve transfers, then euthanized 8-12 mo later. Four served as long-term decentralized only animals. Before euthanasia, pelvic or transferred nerves and L1-S3 spinal roots were stimulated and maximum detrusor pressure (MDP) recorded. Bladder specimens were collected for histological and ex vivo smooth muscle contractility studies. Both reinnervated and decentralized animals showed less or denuded urothelium, fewer intramural ganglia, and more inflammation and collagen, than controls, although percent muscle was maintained. In reinnervated animals, pgp9.5+ axon density was higher compared with decentralized animals. Ex vivo smooth muscle contractions in response to KCl correlated positively with submucosal inflammation, detrusor muscle thickness, and pgp9.5+ axon density. In vivo, reinnervated animals showed higher MDP after stimulation of L1-L6 roots compared with their transected L7-S3 roots, and reinnervated and decentralized animals showed lower MDP than controls after stimulation of nerves (due likely to fibrotic nerve encapsulation). MDP correlated negatively with detrusor collagen and inflammation, and positively with pgp9.5+ axon density and intramural ganglia numbers. These results demonstrate that bladder function can be improved by transfer of obturator nerves to pelvic nerves at 1 yr after decentralization, although the fibrosis and inflammation that developed were associated with decreased contractile function.

Bladder reinnervation by somatic nerve transfer to pelvic nerve vesical branches does not reinnervate the urethra.

AIMS: We sought to determine whether somatic lumbar nerve transfer to the pelvic nerve's anterior vesical branch after sacral decentralization for detrusor muscle reinnervation also leads to aberrant innervation of the bladder outlet. METHODS: Twenty-six female mongrel hound dogs underwent transection of sacral dorsal and ventral spinal roots (ie, sacral decentralization). Immediately afterward, 12 received genitofemoral nerve transfer and 9 received femoral nerve branch transfer. Five were left sacrally decentralized. Controls included 3 sham-operated and 6 unoperated. Eight months postsurgery, the bladder and urethra were injected with retrograde tracing dyes cystoscopically. After 3 weeks, detrusor and urethral pressures were assayed electrophysiologically immediately before euthanasia and characterization of neural reinnervation. RESULTS: Electrical stimulation of spinal cords or roots did not lead to increased urethral sphincter pressure in nerve transfer animals, compared with decentralized animals, confirming a lack of functional reinnervation of the bladder outlet. In contrast, mean detrusor pressure increased after lumbar cord/root stimulation. In sham/unoperated animals, urethral and bladder dye injections resulted in labeled neurons in sacral level neural structures (dorsal root ganglia [DRG], sympathetic trunk ganglia [STG], and spinal cord ventral horns); labeling absent in decentralized animals. Urethral dye injections did not result in labeling in lumbar or sacral level neural structures in either nerve transfer group while bladder dye injections lead to increased labeled neurons in lumbar level DRG, STG, and ventral horns, compared to sacrally decentralized animals. CONCLUSION: Pelvic nerve transfer for bladder reinnervation does not impact urethral sphincter innervation.

Management of Postoperative Lower Urinary Tract Symptoms (LUTS) After Pelvic Organ Prolapse (POP) Repair.

PURPOSE OF REVIEW: Pelvic organ prolapse (POP) is a common condition for which approximately 200,000 US women annually undergo surgical repair [Am J Obstet Gynecol 188:108-115, 2003]. After surgical correction, persistent or new lower urinary tract symptoms (LUTS) can be present. We provide guidance on the current tools to predict, counsel, and subsequently handle postoperative LUTS. The current literature is reviewed regarding LUTS diagnosis and management in the setting of prolapse surgery with an emphasis on newer developments in this area. RECENT FINDINGS: 1. More severe stages of prolapse are positively correlated with obstructive symptoms [Am J Obstet Gynecol 185:1332-1337, 2001], but not with other LUTS [Adv Urol 2013:5673753, 2013, Eur J Obstet Gynecol Reprod Biol 177:141-145, 2014, Am J Obstet Gynecol 199:683, 2008, Int Urogynecol J 21:1143-1149, 2010]. 2. One-week ambulatory pessary trial is an effective way to approximate postoperative results-one study correctly predicted persistent urgency and frequency in addition to occult stress urinary incontinence in 20% of study population [Obstet Gynecol Int 2012:392027, 2012]. 3. No preoperative overactive bladder (OAB) symptom was the best predictor for the absence of de novo OAB symptoms postoperatively [Int Urogynecol J 21:1143-1149, 2010]. 4. Urge incontinence patients respond favorably to sacral neuromodulation [Neurourol Urodyn 26: 29-35, 2007], botulinum toxin, and anticholinergic therapy [Res Rep Urol 8:113-122, 2016 , N Engl J Med, 367:1803-1813, 2012]. 5. Primary bladder outlet obstruction (BOO) can be treated effectively with alpha antagonists or anticholinergics, timed voiding, and pelvic physiotherapy as first-line therapy. Counseling regarding postoperative LUTS is key when planning POP surgery. A thorough understanding of patient history is crucial to successful repair. Patients with significant preoperative symptoms, history of neurologic disease, pelvic floor dysfunction, bladder neck obstruction, or higher stages of anterior wall prolapse may be higher risk for postoperative LUTS. UDS with or without reduction and an ambulatory pessary trial can help prognosticate. Patients will likely maintain a positive therapeutic relationship postoperatively for LUTS if counseled preoperatively.

Exotic looped trajectories of photons in three-slit interference.

The validity of the superposition principle and of Born's rule are well-accepted tenants of quantum mechanics. Surprisingly, it has been predicted that the intensity pattern formed in a three-slit experiment is seemingly in contradiction with the most conventional form of the superposition principle when exotic looped trajectories are taken into account. However, the probability of observing such paths is typically very small, thus rendering them extremely difficult to measure. Here we confirm the validity of Born's rule and present the first experimental observation of exotic trajectories as additional paths for the light by directly measuring their contribution to the formation of optical interference fringes. We accomplish this by enhancing the electromagnetic near-fields in the vicinity of the slits through the excitation of surface plasmons. This process increases the probability of occurrence of these exotic trajectories, demonstrating that they are related to the near-field component of the photon's wavefunction.

Postsurgical volumetric airway changes in 2-jaw orthognathic surgery patients.

INTRODUCTION: Findings from early cephalometric studies on airway changes after 2-jaw orthognathic surgery have been challenged because the previous anteroposterior interpretation of airway changes can now be evaluated in 3 dimensions. The aims of this study were to use cone-beam computed tomography to quantify the nasopharynx, oropharynx, and total airway volume changes associated with skeletal movements of the maxilla and mandible in a sample of patients undergoing 2-jaw orthognathic surgery for correction of skeletal malocclusion. METHODS: Skeletal movements and airway volumes of 71 postpubertal patients (31 male, 40 female; mean age, 18.8 years) were measured. They were divided into 2 groups based on ANB angle, overjet, and occlusion (Class II: ANB, >2°; overjet, >1 mm; total, 35 subjects; and Class III: ANB, <1°; overjet, <1 mm; total, 36 subjects). Presurgical and postsurgical measurements were collected for horizontal, vertical, and transverse movements of the maxilla and the mandible, along with changes in the nasopharynx, oropharynx, and total airways. Associations between the directional movements of skeletal structures and the regional changes in airway volume were quantified. Changes in the most constricted area were also noted. RESULTS: Horizontal movements of D-point were significantly associated with increases in both total airway (403.6 ± 138.6 mm(3); P <0.01) and oropharynx (383.9 ± 127.9 mm(3); P <0.01) volumes. Vertical movements of the posterior nasal spine were significantly associated with decreases in total airway volume (-459.2 ± 219.9 mm(3); P = 0.04) and oropharynx volume (-639.7 ± 195.3 mm(3); P <0.01), increases in nasopharynx (187.2 ± 47.1 mm(3); P <0.01) volume, and decreases in the most constricted area (-10.63 ± 3.69 mm(2); P <0.01). In the Class III patients only, the vertical movement of D-point was significantly associated with decreases in both total airway (-724.0 ± 284.4 mm(3); P = 0.02) and oropharynx (-648.2 ± 270.4 mm(3); P = 0.02) volumes. A similar negative association was observed for the most constricted area for the vertical movement of D-point (-15.45 ± 4.91 mm(2); P <0.01). CONCLUSIONS: Optimal control of airway volume is through management of the mandible in the horizontal direction and the vertical movement of the posterior maxilla for all patients. The surgeon and the orthodontist should optimally plan these movements to control gains or losses in airway volume as a result of orthognathic surgery.

A 1-year study of hydroxyapatite-derived biomaterials in an adult sheep model: III. Comparison with autogenous bone graft for facial augmentation.

BACKGROUND: The present study investigates onlay bone grafts and implants in a large-animal (sheep) model to determine whether there are composite biomaterials that can maximize long-term facial augmentation when compared with conventional bone grafts. METHODS: Facial augmentation was performed in 10 adult sheep. First, 16.8 x 5-mm disks were prepared from autogenous calvarial bone, hydroxyapatite ceramic, ceramic composite of 60 percent hydroxyapatite and 40 percent beta-tricalcium phosphate (60 percent hydroxyapatite ceramic), and hydroxyapatite cement paste. Facial recipient sites were the body of the mandible (depository), the maxillary region (resorptive), and the frontal bone (depository). The volume of all bone grafts and implants was determined using computed tomographic scans, and the amount of bone formation was measured by means of backscatter electron microscopy 1 year postimplantation. RESULTS: Cranial bone graft demonstrated a highly significant reduction in volume in all sites studied. Other than a slight decrease in volume of hydroxyapatite cement paste disks applied to the maxillary region, there was no significant change in volume of the biomaterials implanted in any of the remaining recipient sites. Bone replacement was greatest in hydroxyapatite ceramic (23.9 percent) followed by 60 percent hydroxyapatite ceramic (16.4 percent) and least with hydroxyapatite cement paste (4.2 percent). Minimal differences in bone replacement were noted between recipient sites. CONCLUSIONS: This study demonstrates that the volume maintenance of onlay hydroxyapatite composites is highly predictable, whereas that of cranial bone graft is unpredictable. Minimal differences were seen in bone replacement within biomaterials between "depository" and "resorptive" facial recipient sites. Ceramic forms of onlay hydroxyapatite implants demonstrated significantly greater bone replacement than did the cement paste forms of hydroxyapatite.

A 1-year study of osteoinduction in hydroxyapatite-derived biomaterials in an adult sheep model: part II. Bioengineering implants to optimize bone replacement in reconstruction of cranial defects.

The present study investigated hydroxyapatite biomaterials implanted in critical-size defects in the calvaria of adult sheep to determine the optimal bioengineering of hydroxyapatite composites to facilitate bone ingrowth into these materials. Five calvarial defects measuring 16.8 mm in diameter were made in each of 10 adult sheep. Three defects were filled with cement paste composites of hydroxyapatite and beta-tricalcium phosphate as follows: (1) 100 percent hydroxyapatite-cement paste, (2) 60 percent hydroxyapatite-cement paste, and (3) 20 percent hydroxyapatite-cement paste. One defect was filled with a ceramic composite containing 60 percent hydroxyapatite-ceramic, and the fifth defect remained unfilled. One year after implantation, the volume of all biomaterials was determined by computed tomography, and porosity and bone replacement were determined using backscatter electron microscopy. Computed tomography-based volumetric assessment 1 year after implantation demonstrated that none of the unfilled cranial defects closed over the 1-year period, confirming that these were critical-size defects. There was a significant increase in volume in both the cement paste and ceramic implants containing 60 percent hydroxyapatite (p < 0.01). There was no significant change in volume of the remaining cement paste biomaterials. Analysis of specimens by backscatter electron microscopy demonstrated mean bone replacement of 4.8 +/- 1.4 percent (mean +/- SEM) in 100 percent hydroxyapatite-cement paste, 11.2 +/- 2.3 percent in 60 percent hydroxyapatite-cement paste, and 28.5 +/- 4.5 percent in 20 percent hydroxyapatite-cement paste. There was an inverse correlation between the concentration of hydroxyapatite and the amount of bone replacement in the cement paste for each composite tested (p < 0.01). Bone replacement in 60 percent hydroxyapatite-ceramic composite (13.6 +/- 2.0 percent) was not significantly different from that in 60 percent hydroxyapatite-cement paste. Of note is that the ceramic composite contained macropores (200 to 300 microm) that did not change in size over the 1-year period. All cement paste composites initially contained micropores (3 to 5 nm), which remained unchanged in 100 percent hydroxyapatite-cement paste. Cement paste implants containing increased tricalcium phosphate demonstrated a corresponding increase in macropores following resorption of the tricalcium phosphate component. Bone replacement occurred within the macropores of these implants. In conclusion, there was no significant bone ingrowth into pure hydroxyapatite-cement paste (Bone Source, Stryker-Leibinger Inc., Dallas, Texas) in the present study. The introduction of macropores in a biomaterial can optimize bone ingrowth for reconstruction of critical-size defects in calvaria. This was demonstrated in both the ceramic composite of hydroxyapatite tested and the cement paste composites of hydroxyapatite by increasing the composition of a rapidly resorbing component such as beta-tricalcium phosphate.