Anococcygeal Nerve and Sitting Pain: Differential Diagnosis and Treatment Results.

BACKGROUND: The plastic surgeon is often asked to reconstruct the sacral area related to pilonidal cysts or a tumor, or after other surgery, such as coccygectomy. When sitting pain is not due to the pudendal or posterior femoral cutaneous nerve injury, the anococcygeal nerve (ACN) must be considered. Clinically, its anatomy is not well known. Rather than consider coccygectomy when the traditional nonoperative treatment of coccydynia fails, resection of the ACN might be considered. METHODS: A review of traditional anatomy textbooks was used to establish classical thoughts about the ACN. A retrospective cohort of patients with sitting pain related to the coccyx was examined, and those operated on, by resecting the ACN, were examined for clinicopathologic correlations. RESULTS: When the ACN is described in anatomy textbooks, it is with varying distributions of innervated skin territory and nerve root composition. Most include an origin from sacral 5 and coccygeal 1 ventral roots. Most agree that the ACN forms on the ventral side of the sacrum/coccyx, alongside the coccygeus muscle, to emerge laterally and travel dorsally to innervate skin over the coccyx and lower sacrum. A review of 13 patients with sitting pain due to the ACN, from 2015 to 2019, demonstrated a mean age of 54.6 years. Eleven were female. The etiologies of ACN injury were falls (9), exercise (3), and complication from surgery (1). Six of the 9 patients who had surgery were able to be followed up with a mean length of 36.3 months (range, 11-63 months). Overall, 3 had an excellent result, 2 had a good result, and 1 was not improved. The one with a failed result showed improvement with coccygectomy. CONCLUSIONS: The ACN must be included in the differential diagnosis of sitting pain. It is most often injured by a fall. The ACN can be evaluated with a diagnostic nerve block, can be identified at surgery, and can be resected, and its proximal end can be implanted into the coccygeus muscle. This surgery may prove an alternative to coccygectomy.

Report on 7 Years' Experience Implementing an Undergraduate Medical Curriculum for Osteopathic Medical Students Using Entrustable Professional Activities.

Calls for changes in undergraduate medical education and the advent of the single graduate medical education accreditation system have challenged the osteopathic medical profession to maintain its identity and distinctiveness while adapting to innovations. For the osteopathic medical profession to thrive, its colleges must provide students with an educational framework that solidifies their osteopathic identity. The authors developed an integrated anatomy-clinical skills course at the University of New England College of Osteopathic Medicine, Osteopathic Clinical Skills, that used the performance benchmarks of the Entrustable Professional Activities and the Osteopathic Core Competencies for Medical Students from the American Association of Colleges of Osteopathic Medicine. A primary tenet of osteopathic medicine is the relationship of structure and function; Osteopathic Clinical Skills fuses anatomical sciences with clinical skills and underscores this tenet in clinical diagnosis and treatment. This article describes the development and implementation of an educational framework that integrates anatomy, physical examination, history taking, and other clinical skills with osteopathic medicine principles and practice and osteopathic manipulative treatment.

Defining the Anatomy of the Tendinous Intersections of the Rectus Abdominis Muscle and Their Clinical Implications in Functional Muscle Neurotization.

PURPOSE: Little is known about the definitive course of the tendinous intersections from anterior to posterior through the rectus abdominis (RA) muscle. The implications of a full thickness intersection may have effects on the ability to neurotize the RA. We hypothesized that these tendinous inscriptions would be fully adherent to the anterior rectus sheath, but there would be an incomplete penetrance into the posterior surface, thereby allowing for muscle fibers and neurovascular structures to run the entire course of the RA muscle. METHODS: Fifty-five cadaveric, hemiabdominal walls were evaluated. Measurements were taken of RA muscle thickness, depth of penetrance of the tendinous intersections, and intersection thickness. RESULTS: Of the 32 cadavers, 2 had 4 paired tendinous intersections and the remaining 30 cadavers had 3 paired tendinous intersections. Rectus abdominis muscle belly tended to be thicker at midbelly, between intersections than at the level of the corresponding intersection. A total of 168 tendinous intersections were assessed. Thirty (18%) of these inscriptions proved to be full thickness extending from anterior rectus sheath to posterior rectus sheath without any intervening muscle or neurovascular structures. Twenty-three (42%) of the 55 hemiabdomens assessed had at least one full-thickness tendinous intersection. CONCLUSIONS: The majority of RA muscles have 3 paired tendinous intersections. Most intersections are incomplete and only encompass the anterior rectus sheath. However, there may be a higher percentage of full-thickness intersections than previously appreciated and the clinical relevance behind these remains unclear.

Effects of Group Fitness Classes on Stress and Quality of Life of Medical Students.

CONTEXT: Medical school can produce intense psychological distress in its students; however, there is a paucity of research exploring potential means of improving medical students' well-being. OBJECTIVE: To investigate the relationship between physical exercise and stress and quality of life (QOL) in a medical student population. METHODS: This nonrandomized, controlled, 12-week study used a survey research design. First- and second-year osteopathic medical students at the University of New England College of Osteopathic Medicine were recruited to participate in 1 of 3 groups: (1) students participating in 30-minute CXWORX (Les Mills International LTD) group fitness classes; (2) students exercising alone or with up to 2 additional partners regularly (eg, running, weight lifting), henceforth called the health-enhancement group; and (3) students in a control group who did not engage in regular exercise. Participants completed the Perceived Stress Scale survey once every 4 weeks, as well as visual analog scale surveys to assess physical, mental, and emotional QOL weekly during the course of the study. Statistical significance was defined as P<.05. RESULTS: Sixty-nine participants met the inclusion criteria and completed the study protocol, with 25 in the fitness class group, 29 in the health-enhancement group, and 15 in the control group. Compared with baseline values, the fitness class group demonstrated decreased perceived stress (P=.038) and increased physical QOL (P=.007), mental QOL (P=.046), and emotional QOL (P=.004) after 12 weeks. Participants in the health-enhancement and control groups showed no statistically significant changes between baseline and week 12 for any of these parameters, with the exception of mental QOL, which improved in the health-enhancement group (P=.023). CONCLUSION: Participation in regular group fitness classes led to a statistically significant decrease in perceived stress and an increase in physical, mental, and emotional QOL compared with exercising regularly on one's own or not engaging in regular exercise. Attending weekly group fitness classes could be a solution to improving the emotional well-being and stress level of medical students.

Metabolic characteristics of keto-adapted ultra-endurance runners.

BACKGROUND: Many successful ultra-endurance athletes have switched from a high-carbohydrate to a low-carbohydrate diet, but they have not previously been studied to determine the extent of metabolic adaptations. METHODS: Twenty elite ultra-marathoners and ironman distance triathletes performed a maximal graded exercise test and a 180 min submaximal run at 64% VO2max on a treadmill to determine metabolic responses. One group habitually consumed a traditional high-carbohydrate (HC: n=10, %carbohydrate:protein:fat=59:14:25) diet, and the other a low-carbohydrate (LC; n=10, 10:19:70) diet for an average of 20 months (range 9 to 36 months). RESULTS: Peak fat oxidation was 2.3-fold higher in the LC group (1.54±0.18 vs 0.67±0.14 g/min; P=0.000) and it occurred at a higher percentage of VO2max (70.3±6.3 vs 54.9±7.8%; P=0.000). Mean fat oxidation during submaximal exercise was 59% higher in the LC group (1.21±0.02 vs 0.76±0.11 g/min; P=0.000) corresponding to a greater relative contribution of fat (88±2 vs 56±8%; P=0.000). Despite these marked differences in fuel use between LC and HC athletes, there were no significant differences in resting muscle glycogen and the level of depletion after 180 min of running (-64% from pre-exercise) and 120 min of recovery (-36% from pre-exercise). CONCLUSION: Compared to highly trained ultra-endurance athletes consuming an HC diet, long-term keto-adaptation results in extraordinarily high rates of fat oxidation, whereas muscle glycogen utilization and repletion patterns during and after a 3 hour run are similar.

Quantitative assessment of the ischiofemoral space and evidence of degenerative changes in the quadratus femoris muscle.

BACKGROUND: Injuries to the quadratus femoris (QF) muscle have only recently appeared in the medical literature with the increasing use of advanced imaging in assessing musculoskeletal complaints in the gluteal region. Both strains of the QF muscle and impingement of the QF muscle within the ischiofemoral (IF) space can appear similar on imaging, and normative data of the IF space is important in establishing guidelines for defining these conditions. PURPOSE: One purpose of this study was to quantitatively describe the IF and QF spaces. The second goal of this paper was to describe gross abnormalities seen in the QF muscle, and determine if the appearance of the muscle is associated with pelvimetric measurements. METHODS: Quantitative measurements were taken of the IF and QF spaces on 16 cadavers (29 hips). The QF muscle was then examined and assigned a quantitative grade. RESULTS: The mean IF space was 23.5 ± 4.7 mm and QF space was 20.4 ± 5.6 mm. Abnormalities of the QF muscle were observed in 51.7 % of the hips, and were associated with a greater approximation when moving the hip from neutral to maximally extended-adducted. CONCLUSION: While degenerative changes were present in the majority of QF muscles, these changes were not associated with the size of the IF or QF space. However, there was a significant association between the degree of degenerative change observed and (1) an increased approximation of the QF attachments sites; and (2) a narrower intertuberous diameter.

Misclassification of hybrid fast fibers in resistance-trained human skeletal muscle using histochemical and immunohistochemical methods.

Sixteen healthy untrained women participated in a 6-week progressive resistance training program to compare 2 common methods of classifying fiber types. The women were a subset from a previous study and were randomly divided into 2 groups: traditional strength training (TS, n = 9) and non-exercising control (C, n = 7). The TS group performed 3 lower limb exercises (leg press, squat, and knee extension) using 6-10 repetitions maximum 2 days per week for the first week and 3 days per week for the remaining 5 weeks (17 total workouts). Pre- and posttraining vastus lateralis muscle biopsies were analyzed for fiber type composition using 2 popular methods: myosin adenosine triphosphatase (mATPase) histochemistry and myosin heavy chain (MHC) immunohistochemistry. Six fiber types (I, IC, IIC, IIA, IIAX, and IIX) were delineated using each method separately and in combination. Because of the subjective nature of each method (visual assessment of staining intensities), IIAX fibers expressing a small amount of MHCIIa were misclassified as type IIX using mATPase histochemistry, whereas those expressing a small amount of MHCIIx were misclassified as type IIA using MHC immunohistochemistry. As such, either method used separately resulted in an underestimation of the type IIAX fiber population. In addition, the use of mATPase histochemistry alone resulted in an overestimation of type IIX, whereas there was an overestimation of type IIA using MHC immunohistochemistry. These fiber typing errors were most evident after 6 weeks of resistance training when fibers were in transition from type IIX to IIA. These data suggest that the best approach to more accurately determine muscle fiber type composition (especially after training) is the combination of mATPase histochemical and MHC immunohistochemical methods.

Early-phase muscular adaptations in response to slow-speed versus traditional resistance-training regimens.

Thirty-four untrained women participated in a 6-week program to investigate slow-speed versus "normal" speed resistance-training protocols. Subjects were divided into: slow-speed (SS), normal-speed/traditional-strength (TS), normal-speed/traditional muscular endurance (TE), and non-exercising control (C) groups. Leg press, squats, and knee extensions were performed 2 days/week for the first week and 3 days/week for the remaining 5 weeks (~2 min rest). The SS group performed 6-10 repetitions maximum (6-10RM) for each set with 10 s concentric (con) and 4 s eccentric (ecc) contractions. The TS and TE groups performed sets of 6-10RM and 20-30RM, respectively, at "normal" speed (1-2 s/con and ecc contractions). TE and SS trained at the same relative intensity (~40-60% 1RM), whereas TS trained at ~80-85% 1RM. Pre- and post-training muscle biopsies were analyzed for fiber-type composition, cross-sectional area (CSA), and myosin heavy chain (MHC) content. The percentage of type IIX fibers decreased and IIAX increased in all three training groups. However, only TS showed an increase in percentage of type IIA fibers. CSA of fiber types I, IIA, and IIX increased in TS. In SS, only the CSA of IIA and IIX fibers increased. These changes were supported by MHC data. No significant changes for any parameters were found for the C group. In conclusion, slow-speed strength training induced a greater adaptive response compared to training with a similar resistance at "normal" speed. However, training with a higher intensity at "normal" speed resulted in the greatest overall muscle fiber response in each of the variables assessed.

Interactions of aging, overload, and creatine supplementation in rat plantaris muscle.

Attenuation of age-related sarcopenia by creatine supplementation has been equivocal. In this study, plantaris muscles of young (Y; 5m) and aging (A; 24m) Fisher 344 rats underwent four weeks of either control (C), creatine supplementation (Cr), surgical overload (O), or overload plus creatine (OCr). Creatine alone had no effect on muscle fiber cross-sectional area (CSA) or heat shock protein (HSP70) and increased myonuclear domain (MND) only in young rats. Overload increased CSA and HSP70 content in I and IIA fibers, regardless of age, and MND in IIA fibers of YO rats. CSA and MND increased in all fast fibers of YOCr, and CSA increased in I and IIA fibers of AOCr. OCR did not alter HSP70, regardless of age. MND did not change in aging rats, regardless of treatment. These data indicate creatine alone had no significant effect. Creatine with overload produced no additional hypertrophy relative to overload alone and attenuated overload-induced HSP70 expression.

No change in skeletal muscle satellite cells in young and aging rat soleus muscle.

Satellite cells are muscle stem cells capable of replenishing or increasing myonuclear number. It is postulated that a reduction in satellite cells may contribute to age-related sarcopenia. Studies investigating an age-related decline in satellite cells have produced equivocal results. This study compared the satellite cell content of young and aging soleus muscle in rat, using four different methods: dystrophin-laminin immunohistochemistry, MyoD immunohistochemistry, electron microscopy, and light microscopy of semi-thin sections. The absolute quantity of satellite cells increase with age, but satellite cell percentages were similar in young and aging soleus muscles. There were no differences in satellite cell quantity among MyoD immunohistochemistry, electron microscopy, and semi-thin sections. All three methods had significantly more satellite cells than with dystrophin-laminin immunohistochemistry. We conclude that satellite cell number does not decrease with age and postulate that satellite cell functionality may be responsible for age-related sarcopenia.

Effects of 14 days of microgravity on fast hindlimb and diaphragm muscles of the rat.

The purpose of the present study was to determine the effects of 14 days of microgravity on specific rat fast-twitch muscles, and to compare these data with previous data from rat fast-twitch muscles exposed to microgravity for 10 days (Kraemer et al. 2000). Hindlimb muscles containing predominately fast fibers [extensor digitorum longus (EDL), superficial "white" (GSW) and deep "red" (GDR) gastrocnemius] and the diaphragm (DIA) were removed from flight and ground-based control animals and analyzed for: muscle mass, fiber type distribution, cross-sectional area, and myosin heavy chain (MHC) isoform content. Gravitational unloading for 14 days caused significant decreases in muscle mass (8-9%) and cross-sectional area of almost all fiber types (10-35%) from both EDL and gastrocnemius muscles. However, microgravity had little effect on fiber type composition in these muscles with significant changes occurring only in the EDL type IID fiber population (9.5% decrease). Similarly, relative MHC isoform content was only slightly altered by exposure to microgravity (increased content of MHCIIa in flight EDL). No changes in area, fiber type percentages, or MHC isoform content were detected in the DIA following the 14-day spaceflight. Similar to data gathered following a 10-day spaceflight (Kraemer et al. 2000), the 14-day flight did not appear to cause significant slow-to-fast (I --> IIA) or fast-to-faster (IIA --> IID --> IIB) transformations in hindlimb muscles containing predominantly fast-twitch fibers. However, the longer period of gravitational unloading did result in additional loss in muscle fiber cross-sectional area with involvement of more major fiber types.

Effect of circulating growth hormone on muscle IGF-I protein concentration in female mice with growth hormone receptor gene disruption.

Growth hormone (GH) is a potent secretague for circulating insulin-like growth factor-I (IGF-I). The purpose of this study was to examine the effect of circulating GH on muscle IGF-I protein expression using GH transgenic animal models. Three different models were used: mice that overexpress bovine GH (bGH; n=10), mice without a functional GH receptor (GHR-/-; n=10), and wildtype mice (n=10). All mice were 16-week old females and each group differed in their basic phenotypic characteristics. Immediately after euthanization the triceps surae muscle group (soleus, plantaris, and gastrocnemius muscles) was removed. IGF-I was extracted from the muscle with an acid-ethanol solution (12.5% 2N hydrochloric acid and 87.5% ethanol, pH 1.5) followed by neutralization with Tris-base and subsequently quantified using a radioimmunoassay. Analysis revealed that bGH mice had significantly greater muscle IGF-I protein expression compared to GHR-/- and wildtype mice. No difference in IGF-I protein concentration was found between GHR-/- and wildtype animals. This study found that overexpression of GH leading to high circulating GH concentrations increase muscle IGF-I protein expression. However, the absence of a functional GHR did not affect muscle IGF-I protein expression compared to wildtype despite high circulating levels of GH and low circulating levels of IGF-I. In conclusion, it appears that at rest high circulating levels of GH augment muscle IGF-I protein expression only in the presence of an intact GHR but that the absence of a functional GH receptor does not affect basal levels of muscle IGF-I protein in female mice.

Effects of growth hormone overexpression vs. growth hormone receptor gene disruption on mouse hindlimb muscle fiber type composition.

OBJECTIVE: The present study characterizes the fiber type composition of selected hindlimb muscles from two transgenic mouse lines specifically engineered to alter the amounts of circulating growth hormone (GH) and insulin-like growth factor-1 (IFG-1). DESIGN: The triceps surae muscle group (soleus m., gastrocnemius m., and plantaris m.) was harvested en masse from mice that were: (1) giant due to the expression of a bovine GH transgene (bGH), (2) dwarf due to the disruption of the GH receptor/binding protein gene (GHR-/-), and (3) normal-sized controls [non-transgenic (NT)]. Histochemical and immunohistochemical methods were utilized on serial cross sections to delineate eight fiber types (I, IC, IIC, IIA, IIAD, IID, IIDB, and IIB). Cross-sectional areas were subsequently determined on approximately 50 fibers/type. RESULTS: Compared to NT littermates, muscles from bGH mice demonstrated a significant (p<0.05) fast-to-slow shift in fiber phenotype, as well as significantly larger fibers for most types. In contrast, significantly smaller fibers were found for all fiber types in the GHR-/- mice, with no significant differences in fiber type percentages compared to NT. Regardless of mouse genotype, the hierarchy of fiber size was maintained in each muscle with type I the largest in the soleus m. and type IIB the largest in the predominantly fast muscles (plantaris, superficial and deep gastrocnemius muscles). CONCLUSION: In conclusion, the genetic manipulation of GH expression (bGH) and its receptor binding (GHR-/-) had profound and divergent effects on muscle phenotype. It is hoped that continued research in this area will help elucidate the direct (independent of IGF-1) vs. indirect (via IGF-1 mediating mechanisms) effects of GH.

Short-term high- vs. low-velocity isokinetic lengthening training results in greater hypertrophy of the elbow flexors in young men.

We performed two studies to determine the effect of a resistive training program comprised of fast vs. slow isokinetic lengthening contractions on muscle fiber hypertrophy. In study I, we investigated the effect of fast (3.66 rad/s; Fast) or slow (0.35 rad/s; Slow) isokinetic high-resistance muscle lengthening contractions on muscle fiber and whole muscle cross-sectional area (CSA) of the elbow flexors was investigated in young men. Twelve subjects (23.8 +/- 2.4 yr; means +/- SD) performed maximal resistive lengthening isokinetic exercise with both arms for 8 wk (3 days/wk), during which they trained one arm at a Fast velocity while the contralateral arm performed an equivalent number of contractions at a Slow velocity. Before (Pre) and after (Post) the training, percutaneous muscle biopsies were taken from the midbelly of the biceps brachii and analyzed for fiber type and CSA. Type I muscle fiber size increased Pre to Post (P < 0.05) in both Fast and Slow arms. Type IIa and IIx muscle fiber CSA increased in both arms, but the increases were greater in the Fast- vs. the Slow-trained arm (P < 0.05). Elbow flexor CSA increased in Fast and Slow arms, with the increase in the Fast arm showing a trend toward being greater (P = 0.06). Maximum torque-generating capacity also increased to a greater degree (P < 0.05) in the Fast arm, regardless of testing velocity. In study II, we attempted to provide some explanation of the greater hypertrophy observed in study I by examining an indicator of protein remodeling (Z-line streaming), which we hypothesized would be greater in the Fast condition. Nine men (21.7 +/- 2.4 yr) performed an acute bout (n = 30, 3 sets x 10 repetitions/set) of maximal lengthening contractions at Fast and Slow velocities used in the training study. Biopsies revealed that Fast lengthening contractions resulted in more (185 +/- 1 7%; P < 0.01) Z-band streaming per millimeter squared muscle vs. the Slow arm. In conclusion, training using Fast (3.66 rad/s) lengthening contractions leads to greater hypertrophy and strength gains than Slow (0.35 rad/s) lengthening contractions. The greater hypertrophy seen in the Fast-trained arm (study I) may be related to a greater amount of protein remodeling (Z-band streaming; study II).

Postmortem alterations in the pH range of myofibrillar ATPase activation/inactivation.

A histochemical assay for myofibrillar adenosine triphosphatase (mATPase) activity is routinely utilized in the delineation of fiber types in healthy human skeletal muscle. Each fiber type has a specific pH range of mATPase stability (activation). Outside of this pH range, mATPase activity is labile (inactivated), no reaction product is formed, and the fibers remain unstained. The aim of the present study was to carefully investigate the pH stability/lability of mATPase in postmortem muscles. To this end, vastus lateralis muscle samples were obtained approximately 0.5, 1, 2, 3, and 4 days after death, as well as control samples from a healthy young man and woman. Serial cross sections of the muscle samples were assayed for mATPase activity throughout preincubation pH ranges of 4.15-4.7 and 10.2-10.5 in increments of 0.05 pH units. Myosin heavy chain analysis (as well as a regression analysis comparing fiber type area and relative myosin heavy chain content) verified the mATPase-based fiber types. The pH ranges of mATPase stability/lability for the control samples were as previously reported, and support the use of preincubation pH values of 4.3, 4.6, and 10.4 for the delineation of fiber types in normal human muscle. For the postmortem samples, both quantitative and qualitative changes altered the pH ranges of mATPase activation/inactivation. Quantitative changes consisted of a time-dependent loss of mATPase activity that was inhibited in all fibers outside the pH range of 4.15-10.50. In addition, qualitative changes caused "shifts to the left" in mATPase stability within the fast fiber types (IIA and IIB). As such, complete inhibition of mATPase activity did not occur until preincubation at pH 4.45 and pH 4.30 for fiber types IIA and IIB, respectively. For the postmortem vastus lateralis muscle samples, optimal preincubation pH values for mATPase-based fiber type delineation were pH 4.30, 4.45, and 10.35. The reason for these qualitative changes in mATPase stability is not known. However, postmortem changes such as increased lactate production and marked acidification may play a role.

Effect of an acute period of resistance exercise on excess post-exercise oxygen consumption: implications for body mass management.

Studies have shown metabolism to remain elevated for hours following resistance exercise, but none have gone beyond 16 h, nor have they followed a whole body, high intensity exercise protocol. To examine the duration of excess post-exercise oxygen consumption (EPOC) following a period of heavy resistance exercise, seven healthy men [mean (SD) age 22 (3) years, height 177 (8) cm, mass 83 (10) kg, percentage body fat 10.4 (4.2)%] engaged in a 31 min period of resistance exercise, consisting of four circuits of bench press, power cleans, and squats. Each set was performed using the subject's own predetermined ten-repetition maximum and continued until failure. Oxygen consumption ( ) measurements were obtained at consistent times (34 h pre-, 29 h pre-, 24 h pre-, 10 h pre-, 5 h pre-, immediately post-, 14 h post-, 19 h post-, 24 h post-, 38 h post-, 43 h post-, and 48 h post-exercise). Post-exercise measurements were compared to the baseline measurements made at the same time of day. The was significantly elevated ( P<0.05) above baseline values at immediately post, 14, 19, and 38 h post-exercise. Mean daily values for both post-exercise days were also significantly elevated above the mean value for the baseline day. These results suggest that EPOC duration following resistance exercise extends well beyond the previously reported duration of 16 h. The duration and magnitude of the EPOC observed in this study indicates the importance of future research to examine a possible role for high intensity resistance training in a weight management program for various populations.