Thiel Solution Research Articles

Morphological changes in striated muscle fibres caused by components of the Thiel embalming method.

Thiel-fixed body donors are highly valued for surgical training courses. The pronounced flexibility of Thiel-fixed tissue has been postulated to be caused by histologically visible fragmentation of striated muscle. The aim of this study was to analyse whether a specific ingredient, pH, decay, or autolysis could cause this fragmentation in order to modulate the Thiel solution to adapt specimen flexibility specifically to the needs of different courses. Striated muscle of the mouse was fixed for different time periods in formalin, Thiel solution, and its individual ingredients, and analysed by light microscopy. Further, pH-values of Thiel solution and its ingredients were measured. In addition, unfixed muscle tissue was histologically analysed including Gram staining to investigate a relationship between autolysis, decomposition, and fragmentation. Muscle fixed with Thiel solution for 3 months was slightly more fragmentated than muscle fixed for 1 day. Fragmentation was more pronounced after 1 year of immersion. Three individual salt ingredients showed slight fragmentation. Decay and autolysis had no effect on fragmentation, which occurred regardless of the pH of all solutions. Fragmentation of Thiel-fixed muscle is dependent on fixation time and most likely occurs due to salts present in the Thiel solution. Adjustment of the salt composition in the Thiel solution with verification of the influence on the fixation effect, fragmentation and flexibility of the cadavers could be performed in further studies.

A survey on practices of embalming techniques and usage of soft embalming methods in Indian medical institutes

BackgroundSoft cadavers are becoming increasingly popular for surgical skills development in competency-based medical education curricula. However, few studies evaluate this strategy's viability, dependability, and validity, particularly in India. This study intends to investigate embalming procedures and procedural skills practices at medical institutions. MethodsA validated questionnaire gathered information on demographic details, embalming practices, surgical skill training, willingness to adopt modern embalming techniques and awareness and practice of soft embalming methods. A total of 350 Indian medical institutions were forwarded the questionnaire via email. Responses were analyzed using SPSS version 16, and the Chi-square test was used to examine the association between the two categorical variables. ResultsA study of 350 Indian medical institutions found a 62% response rate. In the studied population, 53.5% (N = 116) of institutes demonstrated procedural skills in undergraduate education as a part of early clinical experience. A total of 54.4% (N = 118) of institutes conducted hands-on surgical training. For postgraduates in surgical departments, voluntary cadaver dissection was offered at 53.9% (N = 117) of institutes. In 78.3% (N = 170) of the institutes, surgical training was performed on formaldehyde-embalmed cadavers. Institutions used proprietary solutions, fresh frozen approaches, Thiel solution, phenol, and saturated salt solutions for embalming. ConclusionThe study highlights disparities in undergraduate teaching and surgical skill training in medical institutes, emphasizing the need for re-evaluating embalming practices to ensure the safety and educational quality. It also highlights underutilization of soft embalming methods, highlighting need for improved training programs and strategies to enhance medical education quality.

Alternative natural and chemical substances to traditional formalin-based embalming fluid for cadaveric dissection: A review

Formalin, a widely used embalming fluid in the preservation of cadavers, poses significant health risks to anatomists, medical students, and the environment. This review article evaluates alternative natural and chemical substances for embalming fluid in cadaveric dissection. We conducted a comprehensive literature search on PubMed, Scopus, and Web of Science, focusing on alternative embalming fluids in the past 20 years. The main outcome of interest was the effectiveness of alternative fluids in preserving cadavers for dissection. The review identified several alternatives, including Thiel's solution, modified Larssen solution, Genelyn, and natural alternatives such as honey and essential oils. Thiel's solution has emerged as a popular alternative, providing excellent preservation and flexibility of cadavers. However, the high costs and the need for specialized equipment limit its widespread adoption. Essential oils and honey have also shown potential as effective, environmentally friendly alternatives to formalin. Future research should optimise the composition and application of these alternatives to improve their cost-effectiveness, feasibility, and environmental impact.

Effect of freezing and embalming of human cadaveric whole head specimens on bone conduction

Background and aimsConserved specimens do not decay and therefore permit long-term experiments thereby overcoming limited access to fresh (frozen) temporal bones for studies on middle ear mechanics. We used a Thiel conservation method which is mainly based on a watery solution of salts. In contrast to pure Formalin, Thiel conservation aims to preserve the mechanical proprieties of human tissue. The aim of this study is to examine the effect of Thiel conservation on bone conduction in the same specimen before and after conservation. MethodsNine ears of five defrosted whole heads were stimulated with a direct, electrically driven, bone anchored hearing system (Baha, Baha SuperPower). The motion produced by bone conduction stimulation was measured with a single point laser Doppler vibrometer (LDV) at the promontory, the ossicular chain, and the round window through a posterior tympanotomy. After the initial experiments, the entire whole heads were placed in Thiel solution. In order to enable direct comparison between fresh frozen and Thiel specimens, our Thiel conservation did not include intravascular and intrathecal perfusion. The measurements were repeated 3 and 12 months later.To determine the effect of freezing, defrosting, and embalming on the whole heads, CT scans were performed at different stages of the experimental procedure. Additionally, three extracted temporal bones were stimulated a Baha, motion of the promontory measured by LDV and embalmed in Thiel solution to investigate the direct impact of Thiel solution on the bone. ResultsThe averaged magnitude of motion on the promontory increased in whole head specimens by a mean of 10.3 dB after 3 months of Thiel embalming and stayed stable after 12 months. A similar effect was observed for motion at the tympanic membrane (+7.2 dB), the stapes (+9.5 dB), and the round window (+4.0 dB). In contrast to the whole head specimens, the motion of the extracted temporal bones did not change after 3 months of Thiel embalming (-0.04 dB in average). CT scans of the whole heads after conservation showed a notable brain volume loss mostly >50% as well as a remarkable change in the consistency and structure of the brain. Partial changes could already be observed before the Thiel embalming but after 1–2 days of defrosting. In an additional experiment, a substitution of brain mass and weight by Thiel fluid did not lead to new deterioration in sound transmission. In contrast, a frozen (non-defrosted) whole head showed a distinctively reduced magnitude of promontory motion before defrosting. DiscussionFor our setup, the vibration of the ear due to bone conduction in the same whole head specimens significantly increased after Thiel conservation. Such an increase was not observed in extracted temporal bone specimens.Due to brain changes in the CT scans, we investigated the consequences of the brain volume changes and structure loss on the frozen brain before defrosting. The loss of brain volume alone could not explain the increase of ear vibrations, as we did not observe a difference when the volume was replaced with Thiel fluid. However, freezing and defrosting of the entire brain seems to have a major influence. Beside the destructive effect of freezing on the brain, the modified conservation method without perfusion changed the brain structure.In conclusion, bone conduction in whole heads depends on the physical condition of the brain, rather than on the conservation.

Preservation of muscle tissue with a formaldehyde-free borax solution for gross anatomy lessons

It is known that formaldehyde has serious toxicological effects on medical students, laboratory workers and environmental health. Recently various scientists search for a safe preservation fluid instead of the formaldehyde. One of them and the famous one is the Thiel’s embalming solution. However, it has been realized that it causes deterioration in muscle tissues. It was determined that this deterioration was caused by the boric acid. In the present study, previously formalin fixed muscle tissues were stored into the alkali form of boron during 40 days. At the end of the trial the appearance of the borax stored cadavers was quite similar to the formalin stored cadavers. In cross-sections taken from the muscle tissues, no deterioration could observe. Additionally, there was no putrid odor; on the contrary, a slight level of formaldehyde odor. In microbiological tests, there was a slight insignificant increase in the total number of bacteria in borax solutions. As a result, it was concluded that borax could be used as a cadaveric storage solution, and it can be more appropriate to use borax instead of boric acid in Thiel's solution.

Vascular survey of the maxillary vestibule and gingiva\u2014clinical impact on incision and flap design in periodontal and implant surgeries

ObjectivesCurrently, empirical clinical findings on the blood supply of the maxillary vestibule are not backed up with sufficient literature. The purpose of this study was to investigate the mucosal and periosteal vascular supply in the maxillary vestibule macroscopically and radiographically to improve surgical strategies and flap designs.Materials and methodsThirty head corpses were selected (9 dentate, 11 partially edentulous, 10 edentulous). Twenty-six corpses were injected by red latex milk and embalmed with Thiel solution. Four cadavers were prepared for corrosion casting. Arterial path and anastomoses in the maxillary vestibule of dentate, partially edentulous and edentulous ridges, were analyzed macroscopically and by computed tomography (CT).ResultsTransverse periosteomucosal anastomoses were detected in the posterior and esthetic zones of the maxillary vestibule. The buccal branches penetrated the interdental septum toward the palate. In the esthetic zone, superior labial artery (SLA) supplied the mucosa and the infraorbital artery (IOA) supplied the periosteum. Corrosion casting showed anastomoses between IOA and nasal septal branches. CT analysis revealed ipsilateral and contralateral anastomoses between SLA and IOA. In dentate ridges, mucosal star-shaped terminal branches were detected.ConclusionsThe macroscopic and radiographic vascular survey analysis revealed the anatomical background behind several clinically documented phenomena related to oral and periodontal surgeries.Clinical relevanceThis study permits clinicians to design less invasive flaps when releasing incisions in the maxillary vestibule during periodontal and implant surgeries. Our observations strongly point to the significance of an undamaged periosteum to prevent compromised flap revascularization and wound healing disturbances.

Detection of Vascular Pathways of Oral Mucosa Influencing Soft- and Hard Tissue Surgeries by Latex Milk Injection.

In this methodological study, the purpose was to visualize the macroscopic vascular pathway of the oral mucosa. Corpses were injected and fixed with Thiel's solution for embalming to keep the natural color, fresh texture, and elasticity of the tissues. Latex milk injection is a technique used to stain blood vessels. A combination of Thiel's embalming method and latex milk injection allows surgeons to work on a raw specimen and identify the distribution and anastomosis of vessels macroscopically in the oral mucosa for flap/incision design in periodontal and maxillofacial surgeries. The latex milk contains radiopaque material that enables clinicians to visualize the pathway of the blood vessels radiographically. A step-by-step protocol is described for the correct adjustment of Thiel embalming and latex milk injection. The combined application of both methods allows the clinician to understand anatomical structures practically. As a result, proper incisions and flaps can be designed, which prevents neurovascular damage, intraoperative bleeding, and postoperative morbidity during patient surgery.

Formolized Cadaveric Specimens Immersion‐Recovery Protocol

Cadaveric dissection, promoted by multiple anatomists and institutions as a fundamental area of medical education and training , requires embalming of the bodies to disinfect and preserve them. Therefore, despite being a known toxic and carcinogenic agent, formaldehyde is still widely used for its characteristics and results. Our objective is to introduce a Formolized Cadaveric Specimens Immersion‐Recovery Protocol developed at our laboratory, the chemical reagents used, performed processes and results. The protocol consists on specimen’s immersion in an aqueous solution of potassium hydroxide (KOH) for its maceration, this process causes chemical reactions like lipids saponification and proteins breakdown. The immersion time varies from one specimen to another; however, KOH concentration should never exceed 10% (w/v), otherwise tissue hydrolysis may occur. After a profuse wash, oxidative degradation is carried out: oxidizing formaldehyde into H2O and CO2 through the degradation of hydrogen peroxide (H2O2). It is extremely important to avoid the contact of this agent with the previously used KOH, which would cause the decomposition of H2O2 into H2O, O2 and hydroxyls, without obtaining a proper formaldehyde oxidation. For this purpose, sodium hypochlorite can also be used, with variable results. To ignore this chemical basis limits the achievement of ideal results. This processes allow to obtain 60% more joint movement on goniometry measures compared with formolized specimens, with a change from grey color generated by formaldehyde to ocher. Likewise, the degradation of formaldehyde allows obtaining minimum levels of it in treated specimens, thus reducing health impact on those who handle the specimens. After the recovery process, our specimens were preserved with a low formaldehyde solution. Anatomy students were invited to a peer‐guided extracurricular activity, they interacted with both formolized and recovered specimens, and a likert questionnaire was used to evaluate their experiences with both techniques. Students referred that recovered specimens looked more realistic and considered them better to work with. They also mentioned recovered corpses had less sensory hassles, like eye watering, airway irritation and coughing. Previous studies have compared Thiel solution and formaldehyde fixation. Thiel‐preserved bodies are considered to be a better choice on dissection and surgical training, since tissues offer a more realistic experience. Nonetheless, this technique has disadvantages such as higher costs, vacuum conservation, and the need of trained personal to handle the specimens. Moreover, some chemicals and infrastructure are not available worldwide. An example of the former scenario is present with Ammonium Nitrate, key component in Thiel’s, which is strictly regulated in several countriesSupport or Funding InformationAnatomy Laboratory, Universidad de Los Andes, School of Medicine

Effects of different cadaver preservation methods on muscles and tendons: a morphometric, biomechanical and histological study.

No prior publication studying the biomechanical and histological properties of cadavers fixed with Logan or modified Logan solution (MLS) was found in the literature. It was aimed in this study to compare MLS fixation and other cadaver preservation procedures regarding the use in basic histological studies, anatomy education and surgical trainings. This study was placed on 35 male 17-week-old Wistar Albino rats. MLS fixated tissues were systematically compared with 10% formalin (F10), saturated salt solution (SSS), Thiel and frozen/thawed (FT) tissues. Organoleptic (color, appearance, flexibility, odor, etc.), morphometric (e.g. length, width and cross-sectional area), biomechanical (Young's modulus, stiffness, maximum load, etc.) and histological (tendon and muscle fiber integrity, nuclear prominence, blur in microscopy, etc.) analyses were conducted. Organoleptic properties of Thiel and SSS fixated muscles and tendons were better preserved than F10 and MLS. No significant difference was observed in gross morphometric properties (e.g. length, width and cross sectional area) following any of the cadaver and tissue preservation techniques. MLS and F10 was observed to increase the stiffness, Young's modulus and maximum load parameters of the tendons. Thiel and SSS fixated tendons had similar mechanical properties to fresh and FT tendons. No effect of fixation solutions on tendons is observed in the histological analysis regarding fiber integrity, nuclear prominence, blur in microscopy, shrinkage of tissues. Thiel solution was observed to distort fiber integrity, nuclear prominence and blur the microscopy of muscle tissue. Thiel and SSS fixated muscles and tendons were observed to absorb more stain with Masson's trichrome staining and appear as darker red. No muscle and tendon shrinkage due to fixative solutions was observed with our fixation method. Pondering the organoleptic (color, appearance, consistency, odor, etc.) and biomechanical analyses (stiffness, Young's modulus, etc.), Thiel and SSS fixed cadavers are more suitable for purposes as surgical trainings and development of new surgical procedures. However, the change in the micro-anatomical structure of the muscles, especially with the Masson's trichrome staining, caused by these two solutions should not be overlooked.

Analysis of blood supply in the hard palate and maxillary tuberosity-clinical implications for flap design and soft tissue graft harvesting (a human cadaver study).

The aim of the present study is to provide a detailed macroscopic mapping of the palatal and tuberal blood supply applying anatomical methods and studying specific anastomoses to bridge the gap between basic structural and empirical clinical knowledge. Ten cadavers (three dentate, seven edentulous) have been prepared for this study in the Department of Anatomy, Semmelweis University, Budapest, Hungary, and in the Department of Anatomy of the Medical University of Graz. All cadavers were fixed with Thiel's solution. For the macroscopic analysis of the blood vessels supplying the palatal mucosa, corrosion casting in four cadavers and latex milk injection in other six cadavers were performed. We recorded major- and secondary branches of the greater palatine artery (GPA) and its relation to the palatine spine, different anastomoses with the nasopalatine artery (NPA), and lesser palatal artery (LPA) as well as with contralateral branches of the GPA. Penetrating intraosseous branches at the premolar-canine area were also detected. In edentulous patients, the GPA developed a curvy pathway in the premolar area. The blood supply around the maxillary tuberosity was also presented. The combination of different staining methods has shed light to findings with relevance to palatal blood supply, offering a powerful tool for the design and execution of surgical interventions involving the hard palate. The present study provides clinicians with a good basis to understand the anatomical background of palatal and tuberal blood supply. This might enable clinicians to design optimized incision- and flap designs. As a result, the risk of intraoperative bleeding and postoperative wound healing complications related to impaired blood supply can be minimized.

Quantitative and Qualitative Comparison of Thiel and Phenol‐Based Soft‐Embalmed skin for Surgical Training

BACKGROUNDSurgical training requires high‐fidelity models to in vivo. Embalmed cadaveric material has long been used as the standard. However, conventional formalin embalming is known to affect the quality of the tissue, compromising the tissue quality for optimal realistic surgical training. The aim of our study was to qualitatively compare Thiel and phenol‐based soft‐embalming techniques in a surgical training setup and to quantitatively compare the mechanical properties of embalmed skin to fresh tissue state.METHODSTwenty‐eight participants (4 experienced ENT and 6 residents; 8 Orthopaedic residents; 4 experienced OTL; 5 experienced Trauma and 1 resident) were involved in surgical workshops comparing Thiel and phenol‐based embalmed bodies. Participants were asked to evaluate pre‐defined aspects pertaining to their appreciation of the skin quality as the usability for skin dissection and suturing.In parallel, mechanical testing of skin flaps was conducted. Skin flaps were harvested from 6 fresh‐frozen thawed cadaveric upper limbs. Skin flaps from each specimen were divided in 3 equal in size sections; one subsection was refrozen, one was Thiel embalmed and the other one was phenol‐based embalmed.The three tissue states were compared together for each specimen, one month of embalming (n=3) or one year after embalming (n=3). Specimens were preloaded and pre‐conditioned before displacement‐controlled cycles were applied using an axial tensile testing machine (MTS, Eden Prairie, MN, USA). The tensile elasticity (Young's modulus) was calculated between loading and unloading state. Statistical analysis was performed using a two‐ way mixed ANOVA with a Holm‐Sidak correction for multiple comparisons.RESULTSQualitatively, 18% of participants rated Thiel as more realistic and preferred this model for skin dissection and suturing; 64% preferred Phenol‐based soft‐embalmed; and 18% rated that both embalming states were comparable.Quantitatively, there were significant differences between the embalming techniques (p < 0.05), but no significant difference were made between embalming time (p = 0.47). Thiel embalmed skin had a significantly lower Young's modulus values compared to fresh state (p < 0.0001). There were no significant differences between phenol‐based embalmed skin and fresh state (p = 0.30).CONCLUSIONAlthough there was variability in the relationship between tissue states, fresh and phenol‐based embalmed state were not consistently stiffer than the other, but both were stiffer than the Thiel embalmed samples; Thiel solution caused the samples to be less stiff than the fresh state. Based on our results, phenol‐based soft‐ embalming preserves the integrity of the skin tensile elasticity better, which could explain the better rating of this embalming technique for the practice of surgical exposures, simulated reconstructions and wound closure. Moreover, phenol‐based embalmed specimens can be prepared for a third of the cost and with none of the elaborate setup required for Thiel embalming.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Experimental determination of the emissivity of bone

Cutting and drilling operations in bone are involved in many orthopedic and otolaryngological surgeries. The temperature elevation of these procedures is potentially harmful to bone and soft tissue cells. The research on this topic aims therefore at minimizing temperature elevation and finding optimal process parameters. Experimental studies are mostly carried out on ex vivo setups using bovine bone material. For temperature measurements, either thermocouples or infrared cameras are used. Infrared cameras have potential advantages, but the emissivity value of the material has to be known. Literature values are scattered and vary within a wide range. An experimental study was carried out to quantify the emissivity using freshly frozen bovine and human bone, as well as human bone samples which were either fixed with Formalin or Thiel solution. Additionally, different surface finishes were used and emissivity was evaluated at different temperatures. The mean emissivity of bone was determined to be ɛ=0.96±0.01 for temperature elevations up to 60 °C. A slightly higher value of ɛ=0.97±0.01 was found for temperatures around 80 °C. No significant differences for human or bovine bone samples, preparation or fixation techniques were found.

Electrical conductivity measurement in Thiel‐embalmed tissue model: relevance to radiofrequency ablation

Thiel-embalmed human cadaveric specimens are used widely for biomedical scientific investigation. This Letter reports electrical impedance measurements of Thiel-embalming solutions from 1 Hz to 32 MHz. Compared with other solutions studied, Thiel solution has the lowest impedance throughout the test spectrum. The electrical conductivity of a Thiel-embalmed liver sample exhibited a relatively flat frequency response from 100 to 500 kHz, which is the frequency range used for electro-surgery and radiofrequency tumour ablation (RFA). It measured 5 Sm−1 compared with 0.22 Sm−1 obtained from ex-vivo fresh pig liver. Using finite element modelling and experimental evaluation, the ablation zone obtained from the Thiel-embalmed liver sample was extremely small due to its much higher conductivity. Hence, it is concluded that Thiel-embalmed tissue cannot be used as a reliable model for RFA evaluation.

Laser Doppler Vibrometric Assessment of Middle Ear Motion in Thiel-Embalmed Heads

Thiel-embalmed human whole head specimens represent an alternative model in middle ear research. Research into middle ear mechanics and the evaluation of active middle ear implants are generally performed on fresh human temporal bone specimens. A drawback of this method is the limited period during which the specimen can be used before tissue decay begins. Tissue conservation that preserves mechanical properties is desirable. Using laser Doppler vibrometry, the movement of the tympanic membrane, stapes, and round window were measured in 23 ears from 15 human whole head specimens embalmed according to Thiel. The ears were acoustically stimulated through the intact external auditory canal. The measurement results were compared with data from the literature. The results were similar to those measured in living subjects and from fresh temporal bones, after excluding measurements with nontypical shapes or low amplitudes, that is, 9% for tympanic membrane, 38% for stapes, and 67% for round window. The best agreement was found for the tympanic membrane (mean difference between 0 and 5.2 dB) and for the stapes measurements (mean difference between 0 and 7.4 dB). Larger differences were found for the round window measurements (mean difference between 3 and 19 dB). For the stimulation levels used, the Thiel specimens behaved linearly in amplitude. The results remained reproducible for more than 20 hours in ambient air, and when the specimen was put back into Thiel solution, the measurements were stable for up to several months between measurements. Our results showed that the middle ears of Thiel-embalmed human whole head specimens can be used to study human middle ear mechanics; however, significant differences in some frequencies, particularly at the round window, have to be considered.

Suitability of Thiel embalmed tendons for biomechanical investigation

The standard post-mortem storage method for biomechanical testing is freezing. Freezing minimally alters the biomechanical characteristics of tendons but only suspends the process of decay. Chemical fixation arrests decay and overcomes risk of infection, but alters the biomechanical properties of tendons. On the other hand, Thiel preservation has been reported to maintain soft tissue consistency similar to that of living tissue. The current study investigates the effects of Thiel embalming on human digitorum profundus tendons (FDP) from fresh-frozen and Thiel embalmed cadavers. Cross-sectional area was measured at pre-load, samples were preconditioned and then ramped at a constant strain-rate to failure. Thiel preserved tendons had statistically lower failure stress with median of 38MPa compared to fresh frozen samples with median of 60MPa (p-value=0.048) and trended to a decreased tangential modulus. To overcome limited donor number and masking factors of age, gender, and time embalmed, we also performed experiments in rat tail tendon fascicle. Similar quasi-static ramp to failure tests were performed with control and Thiel treated sample pairs. Similar differences were observed to those found as in human FDP, however these trends were statistically significant. In both tendons, Thiel preserved samples demonstrated altered failure characteristics, indicating a different collagen fiber/collagen network failure mechanism most likely due to partial denaturing by boric acid in Thiel solution. In conclusion, Thiel embalmed tendons did not faithfully represent the biomechanical characteristics of fresh frozen tendons.

Neuroanatomy of the male pelvis in respect to radical prostatectomy including three‐dimensional visualization

The neuroanatomical structures of the radical prostatectomy (RP) are extensively discussed for their existence, localization and function. Especially structures, e.g. the so-called neurovascular bundle (NVB) that are points of debate in numerous anatomical studies. We review the literature and present our observations in cadaveric specimens, to reconstruct neuroanatomical structures in three dimensions (3D) with the use of appropriate computer applications and produce images of operative fields. We used an internet PubMed survey (http://www.ncbi.nlm.nih.gov) to review recent publications and included back copies of historical neuroanatomical studies from our own library. Our own experimental cadaveric (specimens preserved in Thiel's solution) studies of the autonomic nerve supply of the lower urinary tract were also reviewed. Visualization of the pelvic anatomy and neuroanatomy was done using computer-based software packages. No unified terminology for the structures of the NVBs can be presented to date. The innervation of the smooth muscular structures of the urethra and the complex morphology of urethral sphincter remain unclear. Our cadaveric studies showed that nerves are located on the lateral aspect of the prostate in addition to the NVBs described at the dorsolateral side of the prostate. The neuroanatomical investigations of the male pelvis and visualization of the structures in 3D enable the presentation of operative sites as seen intraoperatively. Moreover, dynamic depiction of the pelvic floor is also possible.

THE PELVIC PLEXUS AND ANTIREFLUX SURGERY: TOPOGRAPHICAL FINDINGS AND CLINICAL CONSEQUENCES

Voiding dysfunction and urinary retention are rare complications of antireflux surgery. As mainly reported after bilateral antireflux surgery with extravesical technique, bladder insufficiency has been suspected to be caused by intraoperative damage to neural structures. We studied the topography of the pelvic plexus and assessed the injury to the plexus resulting from antireflux surgery. Human cadavers fixed with Thiel solution were used for dissection. The superior hypogastric plexus and hypogastric nerves were identified as the pathway to the pelvic plexus. After dissecting the surrounding fatty tissue the S2 to S4 nerves and efferent nerve bundles from the pelvic plexus were identified. The main portion of the pelvic plexus was located about 1.5 cm. dorsal and medial to the ureterovesical junction. The bundles of the pelvic plexus ended at the distal ureter, trigone and rectum. When simulating an antireflux procedure, there was a high risk of injury to the pelvic plexus and its efferent nerves if dissection was performed distal to the ureter and dorsal trigone. Careful dissection close to the ureter avoids inadvertent injury to the pelvic plexus. To minimize the risk of voiding dysfunction bilateral antireflux surgery should be performed at 2 sessions unless the operative technique allows preservation of the neural structures.

Wavelength-dependent electromagnetic parameters for coherent propagation in correlated distributions of small-spaced scatterers

Earlier results for coherent propagation of electromagnetic waves in pair-correlated random distributions of scatterers (of radius a and physical parameters ε′,μ′) with minimum separation of centers b≥2a small compared to wavelength (2π/k) are generalized to obtain polarization, refraction, and absorption terms to order k2. The development includes multiple scattering and multipole coupling by electric and magnetic dipoles, as well as quadrupoles to appropriate order. The correlation aspects are determined by simple integrals of the statistical mechanics radial distribution function f for impenetrable particles (spheres, cylinders, and slabs) of diameter b. For slab scatterers, in terms of the exact Zernike–Prins f, the correlation integrals are expressed as algebraic functions of the volume fraction w; the resultant bulk values reduce to those of one particle at full packing, w=1. Similar results are obtained for spheres in terms of the Wertheim–Thiel solution of the Percus–Yevick approximation of f at the unrealizable bound w=1.