Molecular basis of urostyle development in frogs: genes and gene regulation underlying an evolutionary novelty.

Evolutionary novelties entail the origin of morphologies that enable new functions. These features can arise through changes to gene function and regulation. One key novelty is the fused rod at the end of the vertebral column in anurans, the urostyle. This feature is composed of a coccyx and a hypochord, both of which ossify during metamorphosis. To elucidate the genetic basis of these features, we used laser capture microdissection of these tissues and did RNA-seq and ATAC-seq at three developmental stages in tadpoles of Xenopus tropicalis. RNA-seq reveals that the coccyx and hypochord have two different molecular signatures. Neuronal (TUBB3) and muscle markers (MYH3) are upregulated in coccygeal tissues, whereas T-box genes (TBXT, TBXT.2), corticosteroid stress hormones (CRCH.1) and matrix metallopeptidases (MMP1, MMP8 and MMP13) are upregulated in the hypochord. ATAC-seq reveals potential regulatory regions that are observed in proximity to candidate genes that regulate ossification identified from RNA-seq. Even though an ossifying hypochord is only present in anurans, this ossification between the vertebral column and the notochord resembles a congenital vertebral anomaly seen prenatally in humans caused by an ectopic expression of the TBXT/TBXT.2 gene. This work opens the way to functional studies that can elucidate anuran bauplan evolution.

Coccygodynia in a Long-Term Cancer Survivor Diagnosed with Metastatic Cancer: A Case Report.

Background and Objectives: Rectal cancer is considered cured if no recurrence is found during the 5-year follow-up period after treatment. After this period, patients often believe that the cancer is completely eradicated. However, in modern society, where lifespans have become longer, it is important to recognize that metastatic cancer may occur long after the initial treatment has concluded. This highlights the necessity of continued vigilance and the long-term follow-up of cancer survivors. Case report: We present a case of metastatic cancer of the coccyx in an 87-year-old female patient. This patient had undergone successful surgery and treatment for rectal cancer 10 years prior. She was considered cured after the standard 5-year follow-up period as she showed no signs of recurrence. The patient presented with simple coccygeal pain as the main complaint, without any other accompanying symptoms such as weight loss, fever, or changes in bowel habits, typically associated with cancer recurrence. During the clinical evaluation, irregularities in the bone cortex were detected while performing a nerve block using ultrasound. Given these findings, further diagnostic evaluations were performed. Advanced imaging techniques including MRI and CT scans led to a diagnosis of coccygeal metastasis. Conclusions: While the 5-year mark post-treatment is a significant milestone for rectal cancer patients, it does not guarantee the absolute eradication of the disease. Long-term monitoring and a thorough evaluation of new symptoms are essential for the early detection and management of late metastatic recurrences. This approach ensures that patients receive timely and appropriate care, potentially improving outcomes and quality of life.

Iatrogenic rectal perforation after coccygeal radiofrequency ablation.

Coccygodynia (pain of the coccygeal bone) can be treated locally with anti-inflammatory drugs, local steroid injections, surgical removal of the coccyx and, more recently, with radiofrequency thermal ablation. Complications, such as perforation of the colon, can occur as a consequence of the close relationship between the rectum and the sacrococcyx and with the heat from the thermal ablation expanding to the surrounding tissue causing delayed damage with severe consequences. The treatment of this complication requires the combined effort of the gastrointestinal surgeon as well as a gastroenterologist. In this case report, we describe the treatment of this complication and the clinical course after a perforation of the rectum due to thermal ablation of the coccyx to treat long-standing coccygodynia.

Coccygectomy for refractory coccydynia, old-fashioned but effective procedure: A retrospective analysis.

PURPOSE: Coccydynia, characterized by persistent pain in the coccygeal region, significantly impacts patients' quality of life. While various treatment modalities exist, including conservative measures and surgical interventions like coccygectomy, optimal management remains unclear. This retrospective cohort study aimed to compare the clinical outcomes, functional improvements, and quality of life in patients with chronic coccydynia undergoing either infiltrative treatment or coccygectomy. METHODS: Data from patients treated at our institution from January 2018 to December 2022 were analyzed. Participants meeting inclusion criteria were divided into two groups: Group A underwent coccygectomy, while Group B received conservative therapy. Clinical assessments, radiographic evaluations, and patient-reported outcomes were collected preoperatively and at follow-up intervals. RESULTS: Of the 223 initially examined patients, 55 met inclusion criteria. Group A (n = 21) underwent coccygectomy, while Group B (n = 34) received conservative therapy. Both groups showed significant pain reduction post-intervention, with sustained improvement in Group A. Functional outcomes favoured Group A, with significant improvements in disability and quality of life measures. Complications were minimal, with only one case of superficial wound infection in Group A. CONCLUSION: Our findings suggest that coccygectomy provides superior and lasting pain relief, functional improvement, and quality of life improvement compared to conservative therapy. While complications were minimal, further research with larger cohorts is warranted to validate these results and explore long-term outcomes. Despite its historical association with complications, advancements in surgical techniques and perioperative care have led to improved outcomes and reduced complication rates. Thus, coccygectomy should be considered in the treatment algorithm for patients with debilitating coccydynia.

Surgical management of a rare giant sacral meningocele in a child.

INTRODUCTION: Anterior sacral meningocele is a rare congenital disorder, occurring isolated or in syndromic disease. CASE REPORT: A 15-year-old patient who complained of abdominal pain and urinary dysfunction was managed surgically. Imaging diagnosed a giant presacral meningocele and agenesis of the coccyx. DISCUSSION: The presentation of sacral meningocele can be poorly symptomatic, which is why some patients are diagnosed late. Sometimes, diagnosis is suggested by non-specific abdominal symptoms or complications. Abdominal-pelvic radiological examination and lumbar spine MRI are essential, and treatment must be surgical. There are several surgical approaches, but currently no consensus. CONCLUSION: An unusual huge presacral cystic mass in a young patient may be isolated or part of a syndrome, and can be asymptomatic for a long time, leading to late diagnosis. The surgical approach should be based on multidisciplinary discussion. We operated on a giant anterior sacral meningocele in a child using a posterior approach, with a satisfactory result.

Coccydynia: A Review of Anatomy, Causes, Diagnosis, and Treatment.

¼ Coccydynia is a painful condition affecting many patients at the terminal caudal end of the spine.¼ An understanding of coccyx anatomy and variations of morphology is necessary for proper diagnosis. A multifactorial etiology for pain may be responsible for this clinical entity.¼ Several treatment options exist. Successful outcomes for patients depend on individual patient characteristics and the etiology of pain.

Mind the gap: paramedian approach for coccygectomy.

BACKGROUND CONTEXT: Coccydynia is pain in the coccyx that typically occurs idiopathically or from trauma. Most forms are self-limiting. However, if symptoms persist, nonsurgical treatment options can include offloading, NSAIDs, physical therapy, and steroid injections. If all treatment options fail, a growing body of evidence supports a coccygectomy for symptomatic relief. The standard approach for a coccygectomy involves a midline incision cephalad to the anus along the gluteal cleft. Historically, this method has had high rates of infection. PURPOSE: To improve healing and decrease infection rate, we propose the paramedian approach to a coccygectomy. This approach has the benefit of distancing the surgical site from the anus, diminishing the crevice effect of the incision, and increasing the dermal and subdermal thickness for improved surgical closure. STUDY DESIGN/SETTING: We present a case series study of 41 patients who underwent the paramedian approach coccygectomy using a 4 to 6 cm incision, approximately 0.5 to 1.5 cm lateral to the midline, for coccyx removal. These patients were evaluated postoperatively to determine infection rate and various outcome measures. PATIENT SAMPLE: Forty-one patients suffering from refractory coccydynia had a coccygectomy via the paramedian approach between 2011 and 2022 by the senior author. OUTCOME MEASURES: Outcome measures included self-reported measures (Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) pain scale and satisfaction with procedure), physiologic measures (presence of infection and treatment provided) and functional measures (return to vocation/avocation). METHODS: Data was compiled and transferred to Microsoft Excel and analyzed. Two-tailed T-tests were used to compare the patient improvement in VAS and ODI as appropriate for statistical analysis. RESULTS: The patients' average age was 45.8 years. Patients' average body mass index was 27.9, with 71% of patients overweight or obese. A total of 68% of patients were female. Trauma was the most common precipitating factor (75.6%). Five patients presented with postoperative complications (12.1%), one requiring an incision and drainage, and four others were treated with antibiotics for wound erythema. Postoperative evaluations showed continual improvement, with the most significant improvement reported greater than 1-year postoperatively. The Visual Analogue Scale for pain dropped from 7.5 to 2.3 (p<.001), and the Oswestry Disability Index improved from 30.1 to 9.6 (p<.001). A total of 86.7% of patients reported either a good or excellent result. CONCLUSION: Coccygectomies via the midline approach have a variable infection rate, likely due to proximity of the incision to the anus and due to the crevice effect of the gluteal cleft in terms of aeration. These contributing factors are overcome in the paramedian approach, making it an effective option for treating refractory coccydynia that is nonresponsive to conservative management.

[Treatment options for coccygodynia]. / Therapieoptionen bei der Coccygodynie.

BACKGROUND: To this day, patients with coccyx problems are the most frequently underestimated patient population in orthopedic practices. The clinical picture of coccygodynia was first described in 1859. Nevertheless, discussions about the importance of coccyx problems remain a tiresome topic. All patients have in common that they have gone through a long ordeal with many therapists, examinations and therapeutic approaches without having received a real diagnosis. DIAGNOSTIC: The main symptom of coccygodynia is the pain directly on the lowest segment of the coccyx, which often only occurs when sitting and is intensified by the change in position, usually from a sitting to a standing position. Trauma can only be described as the trigger in 50% of cases. Women are four times more likely to be affected than men. The gold standard for imaging should be viewed from standing and seated dynamic lateral radiographs of the coccyx. TREATMENT: After the diagnosis has been made, conservative treatment should first be started with oral NSAIDs, relief with a coccyx cushion with a recess and, if necessary, physiotherapy to strengthen or loosen the pelvic floor. Local infiltrations with a glucocorticoid and local anesthetic directly in the painful area are also often promising. If the symptoms persist for more than 6 months, surgical treatment in the sense of removing the coccyx can be discussed with the patient. The literature shows a success rate of 80-90% if the indication was correct.

Imaging study of coccygeal morphology in adolescent idiopathic scoliosis.

The correlation between scoliosis and sagittal curvature of the cervical, thoracic, and lumbar spine have already been reported in previous studies. However, as a part of the spine, the change in coccygeal morphology in AIS patients has not yet been studied. In this study, a retrospective analysis was performed on 400 patients who were divided into a non-scoliotic group (206 patients) and an AIS group (194 patients). The Postacchini coccygeal radiological classification that was modified by Nathan was used to observe and compare the sagittal coccygeal morphology between the two groups. The results showed that the non-scoliotic group had the highest percentage (52.4%) of patients with type I and the lowest (3.4%) proportion of patients with type V; moreover, the AIS group had the highest percentage (69.1%) of patients with type I and the lowest (1.5%) proportion of patients with type V. The coccygeal morphology was significantly different between the non-scoliotic group and the AIS group (P = 0.001). No significant differences in coccygeal morphology were found between the males and females in the two groups (mild and moderate scoliosis and different segmental scoliosis). In addition, a significant correlation between coccygeal morphology and scoliosis (P = 0.035) was found. In conclusion, coccygeal morphology significantly differs between AIS patients and non-scoliotic adolescents. There was a smaller proportion of patients with a type I coccyx and a larger proportion of patients with a type II or type III coccyx in the AIS group than in the non-scoliotic group. In other words, the presence of a more pronounced coccygeal curve in AIS patients may be caused by an incorrect sitting position and an imbalance in the contraction of the pelvic muscles. It should be further studied whether correcting the sitting position and muscular imbalances could change coccygeal morphology and subsequently affect the development of AIS.

Sacrum and Coccyx Shape Changes During Pregnancy and After Delivery.

Remodeling of the sacrum and coccyx to accommodate pregnancy and delivery has been hypothesized but not directly quantified. This study aimed to quantify the remodeling of the sacrum and coccyx by comparing midsagittal lengths, angles, curvature, and shape between nulliparous, pregnant, and parous women using both 2 and 3 dimensional measures. Ninety pelvic magnetic resonance images of the pelvis were retrospectively collected and segmented. Twelve length, angle, and curvature measurements were made using definitions from previous literature on the midsagittal plane to define the sacrum, coccyx, and combined sacrum-coccyx shape. These measures were followed by a statistical shape analysis, which returned modes of variation and principal component scores. A separate MANCOVA analysis was conducted for both the 2D and 3D measures. The 2D and 3D analyses agreed that pregnant women had a significantly straighter coccyx and combined sacrum/coccyx than nulliparous (9.1% and 5.6%, respectively) and parous (7.5% and 2.7%, respectively) subjects. All comparisons showed that, on average, a pregnant woman's sacrum and coccyx were significantly straighter than their nulliparous counterparts. Then after delivery, the sacrum/coccyx returned, but not completely back to a more curved configuration.

Minimally Invasive Open Reduction and Maintenance Technique for Anterior Sacrococcygeal Dislocation: A Case Report.

Anterior dislocation of the coccyx is rare, but it can occur due to trauma. Conservative treatment is usually performed. However, dislocation reduction may be required to control severe pain in the acute phase or to prevent chronic complications. If manual reduction fails, open reduction is required. The extent of the incision and the method used to maintain the reduction should be considered during open reduction. A 56-year-old male patient experienced a dislocation of the sacrococcygeal joint after falling backwards. Despite conservative treatment, the patient complained of persistent pain during sitting and when using the bathroom. A manual reduction was attempted but failed. We performed joystick reduction via minimal incision and maintained the reduction using a one-strand trans-osseous suture passing through the skin. The patient was advised to use a soft cushion when sitting or lying down for four weeks after surgery. The supine position was not restricted. The patient's symptoms significantly improved after surgery. At the 6-month follow-up, the sacrococcygeal joint showed good alignment and no surgical complications occurred. During the treatment of sacrococcygeal dislocation, the rapid alleviation of acute pain and minimizing potential complications are key points. If open reduction is needed, the minimally invasive reduction technique with a one-strand trans-osseous suture may offer patient satisfaction and a good surgical outcome.

The overlooked symptom of coccydynia: evaluation of sacrococcygeal morphologic and morphometric findings.

BACKGROUND: Coccydynia is one of the most overlooked symptoms in daily clinical practice. Definitions for radiologic evaluation are controversial. OBJECTIVES: We aimed to compare the morphology and morphometric measurements of the sacrococcygeal region with those of a healthy population to support radiologic decision-making. MATERIALS AND METHODS: In total, 26 traumatic and 50 idiopathic cases of coccydynia as well as 74 healthy control cases were retrospectively compared. The morphologic type of the coccyx, the presence of fusion, and the number of coccygeal segments were evaluated in both groups. Morphometric parameters such as sacrococcygeal angle (SCA), sacrococcygeal joint angle (SCJA), intercoccygeal angle (ICA), sacral slope (SS), coccyx curved length (CCL), sacrum curved length (SCL), coccyx length (CL), sacrum length (SL), and sacrococcygeal total length (SCTL) were investigated. RESULTS: Significant differences were found between the coccydynia group and the healthy control group in morphologic parameters such as female gender, coccyx segment, coccyx morphology, presence of sacrococcygeal joint, and segment of sacrococcygeal joint fusion (p < 0.05). In morphologic measurements, SCJA, SCL, SL, coccyx and sacrum curvature indexes were significantly increased (p < 0.05). No significant difference was found in the morphologic and morphometric parameters evaluated when compared with the duration of coccydynia (p > 0.05). CONCLUSION: An increase in the SCJA, SCL, SL, SCI, and coccyx curvature index measurements predisposes to coccydynia. It would be more accurate to perform radiological evaluation by familiarization with these morphologic and morphometric parameters.

Does primary tumor resection improve survival for patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at diagnosis ?

BACKGROUND: Recent studies demonstrated that primary tumor resection (PTR) improves survival of patients with metastatic bone sarcomas. However, it remains quite unclear regarding the role of PTR in the treatment of sarcomas of pelvic bones with synchronous metastasis at diagnosis. METHODS: Using the Surveillance, Epidemiology, and End Results Program, we enrolled a total of 385 patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at initial diagnosis, including 139 patients with osteosarcoma, 176 with Ewing sarcoma, and 70 with chondrosarcoma. Association between PTR and disease-specific survival (DSS) were investigated using the univariable and multivariable Cox regression models. Hazard ratio (HR) and 95% confidence interval (CI) were reported. Representative institutional PTR strategies and clinical outcomes for patients with metastatic pelvic sarcomas from our cancer center were displayed. RESULTS: The usage rate of PTR was 28.1% (39/139) in osteosarcoma, 13.6% (24/176) in Ewing sarcoma, and 41.4% (29/70) in chondrosarcoma with synchronous metastatic lesions. PTR was not associated with an improved DSS for metastatic pelvic osteosarcoma (HR = 0.686, 95% CI = 0.430 ~ 1.094, P = 0.113) and Ewing sarcoma (HR = 0.580, 95% CI = 0.291 ~ 1.154, P = 0.121). The use of PTR was associated with an improved DSS for metastatic pelvic chondrosarcoma (HR = 0.464, 95% CI = 0.225 ~ 0.954, P = 0.037). CONCLUSION: Primary lesion resection may provide a survival benefit for metastatic chondrosarcoma, but not for osteosarcoma and Ewing sarcoma of pelvic bones, sacrum, and coccyx. This population-based study recommends an active surgical intervention for metastatic chondrosarcoma while non-surgical treatment for metastatic osteosarcoma and Ewing sarcoma of the pelvis in terms of survival improvement.

The Study of the Caudal Vertebrae of Thick-Toed Geckos after a Prolonged Space Flight by X-ray Phase-Contrast Micro-CT.

The proximal caudal vertebrae and notochord in thick-toed geckos (TG) (Chondrodactylus turneri, Gray, 1864) were investigated after a 30-day space flight onboard the biosatellite Bion-M1. This region has not been explored in previous studies. Our research focused on finding sites most affected by demineralization caused by microgravity (G0). We used X-ray phase-contrast tomography to study TG samples without invasive prior preparation to clarify our previous findings on the resistance of TG's bones to demineralization in G0. The results of the present study confirmed that geckos are capable of preserving bone mass after flight, as neither cortical nor trabecular bone volume fraction showed statistically significant changes after flight. On the other hand, we observed a clear decrease in the mineralization of the notochordal septum and a substantial rise in intercentrum volume following the flight. To monitor TG's mineral metabolism in G0, we propose to measure the volume of mineralized tissue in the notochordal septum. This technique holds promise as a sensitive approach to track the demineralization process in G0, given that the volume of calcification within the septum is limited, making it easy to detect even slight changes in mineral content.

Evaluation of accuracy, reliability, quality, and readability of online patient information materials on coccyx injury.

The aim of this research is to evaluate the websites containing "coccydynia, coccyx trauma or fracture" in terms of readability, reliability, accuracy, and quality. Searches for "coccydynia, coccyx trauma, coccyx fracture" were carried out in the 3 most used search engines in the USA: Google, Yahoo, and Bing in February 2022. A total of 141 websites were rated by 2 different neurosurgeons for the "Global Quality Score" and "Alexa Popularity Rank." 97.2% of the sites examined include the definition of the disease, 66% include the importance of the disease, 92.9% include the symptoms of the disease, 88.7% include the treatment of the disease, 78% include the signs of the disease, 77.3% include the mechanism of the disease It has been determined that the websites examined within the scope of the research have high global quality score (GQS) and APR and are enriched with images to a large extent.