Review of saturation decompression procedures used in commercial diving.

Introduction: This is a review of commercial heliox saturation decompression procedures. The scope does not include compression, storage depth or bell excursion dive procedures. The objectives are to: identify the sources of the procedures; trace their evolution; describe the current practice; and detect relevant trends. Methods: Eleven international commercial diving companies provided their diving manuals for review under a confidentiality agreement. Results: Modern commercial diving saturation procedures are derived from a small number of original procedures (United States Navy, Comex, and NORSOK). In the absence of relevant scientific studies since the late 80's, the companies have empirically adapted these procedures according to their needs and experience. Such adaptation has caused differences in decompression rates shallower than 60 msw, decompression rest stops and the decision to decompress linearly or stepwise. Nevertheless, the decompression procedures present a remarkable homogeneity in chamber PO2 and daily decompression rates when deeper than 60 msw. The companies have also developed common rules of good practice; no final decompression should start with an initial ascending excursion; a minimum hold is required before starting a final decompression after an excursion dive. Recommendation is made for the divers to exercise during decompression. Conclusions: We observed a trend towards harmonisation within the companies that enforce international procedures, and, between companies through cooperation inside the committees of the industry associations.

A Longitudinal Evaluation of Coronavirus Disease 2019 and Its Effects on Spinal Decompressions With or Without Fusion.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: The objectives were to (1) compare the safety of spine surgery before and after the emergence of coronavirus disease 2019 (COVID-19) and (2) determine whether patients with a history of COVID-19 were at increased risk of adverse events. SUMMARY AND BACKGROUND DATA: The COVID-19 pandemic had a tremendous impact on several health care services. In spine surgery, elective cases were canceled and patients received delayed care due to the uncertainty of disease transmission and surgical outcomes. As new coronavirus variants arise, health care systems require guidance on how to provide optimal patient care to all those in need of our services. PATIENTS AND METHODS: A retrospective review of patients undergoing spine surgery between January 1, 2019 and June 30, 2021 was performed. Patients were split into pre-COVID or post-COVID cohorts based on local government guidelines. Inpatient complications, 90-day readmission, and 90-day mortality were compared between groups. Secondary analysis included multiple logistic regression to determine independent predictors of each outcome. RESULTS: A total of 2976 patients were included for analysis with 1701 patients designated as pre-COVID and 1275 as post-COVID. The pre-COVID cohort had fewer patients undergoing revision surgery (16.8% vs 21.9%, P < 0.001) and a lower home discharge rate (84.5% vs 88.2%, P = 0.008). Inpatient complication (9.9% vs 9.2%, P = 0.562), inpatient mortality (0.1% vs 0.2%, P = 0.193), 90-day readmission (3.4% vs 3.2%, P = 0.828), and 90-day mortality rates (0.8% vs 0.8%, P = 0.902) were similar between groups. Patients with positive COVID-19 tests before surgery had similar complication rates (7.7% vs 6.1%, P = 1.000) as those without a positive test documented. CONCLUSIONS: After the emergence of COVID-19, patients undergoing spine surgery had a greater number of medical comorbidities, but similar rates of inpatient complications, readmission, and mortality. Prior COVID-19 infection was not associated with an increased risk of postsurgical complications or mortality. LEVEL OF EVIDENCE: Level III.

3D-Printed Model in Preoperative Planning of Sciatic Nerve Decompression Because of Heterotopic Ossification: A Case Report.

CASE: A 31-year-old patient presented with an encapsulated sciatic nerve secondary to extensive hip heterotopic ossification (HO), which prevented visualization of a safe osteotomy site to avoid nerve damage. The 3D-printed model demonstrated an easily identifiable osseous reference point along the inferior aspect of the heterotopic mass, allowing for a vertical osteotomy to be safely performed. CONCLUSION: HO is associated with loss of normal anatomic topography. The current case report illustrates the use of a 3D-printed model to identify pertinent anatomic landmarks required for safe decompression of an encapsulated sciatic nerve within the anatomic region of the hip.

A novel method for tracking nitrogen kinetics in vivo under hyperbaric conditions using radioactive nitrogen-13 gas and positron emission tomography.

Decompression sickness (DCS) is caused by gaseous nitrogen dissolved in tissues forming bubbles during decompression. To date, no method exists to identify nitrogen within tissues, but with advances in positron-emission tomography (PET) technology, it may be possible to track gaseous radionuclides into tissues. We aimed to develop a method to track nitrogen movement in vivo and under hyperbaric pressure that could then be used to further our understanding of DCS using nitrogen-13 (13N2). A single anesthetized female Sprague-Dawley rat was exposed to 625 kPa, composed of air, isoflurane, and 13N2 for 10 min. The PET scanner recorded 13N2 during the hyperbaric exposure with energy windows of 250-750 keV. The PET showed an increase in 13N2 concentration in the lung, heart, and abdominal regions, which all reached a plateau after ∼4 min. This showed that it is possible to gain noninvasive in vivo measurements of nitrogen kinetics through the body while at hyperbaric pressures. Tissue samples showed radioactivity above background levels in the blood, brain, liver, femur, and thigh muscle when assessed using a γ counter. The method can be used to evaluate an array of challenges to our understanding of decompression physiology by quantifying nitrogen load through γ counts of 13N2, and signal intensity of the PET. Further development of the method will improve the specificity of the measured outcomes, and enable it to be used with larger mammals, including humans.NEW & NOTEWORTHY This article describes a method for the in vivo quantification and tracking of nitrogen through the mammalian body whilst exposed to hyperbaric pressure. The method has the potential to further our understanding of decompression sickness, and quantitatively evaluate the effectiveness of both the treatment and prevention of decompression sickness.

Hypoglossal and Glossopharyngeal Nerve Palsy After Anterior Cervical Decompression and Fusion: A Case Report.

CASE: A 69-year-old man underwent a C3-4 anterior cervical discectomy and fusion and developed postoperative hypoglossal and glossopharyngeal palsies that resolved with symptomatic treatment. CONCLUSION: Cranial nerve palsy is a rare and possibly under-reported injury after higher-level cervical spine surgery. Conscientious positioning and awareness of these nerves during surgical exposure are crucial to minimizing cranial nerve palsies. Proper workup to identify these palsies and differentiate them from other complications is necessary to guide proper treatment.

Evaluation of core decompression outcome in systemic lupus erythematosus with hip osteonecrosis: a retrospective cohort study.

BACKGROUND: Osteonecrosis is a major cause of morbidity for patients with systemic lupus erythematosus (SLE). Although core decompression is an approved and trusted technique to prevent further joint deterioration, this surgical method seems to be less beneficial for SLE patients. We aimed to evaluate the outcomes of core decompression in SLE patients with primary stages of femoral head osteonecrosis. METHODS: In this study, 23 patients (39 affected hip joints) with osteonecrosis of the femoral head with stage II of the disease, based on the Ficat-Arlet classification system, underwent core decompression. Also, patients demographic characteristics, clinical data, medication history, comorbidities, immunological findings, hip plain radiographs, history of total hip arthroplasty after core decompression, and patients satisfaction with joint function according to the Oxford hip score questionnaire were obtained. RESULTS: In the study, 53.8% of affected joints showed signs of radiographic deterioration in follow-up imaging. Sixty-one and a half percent (61.5%) of patients had unsatisfactory joint performance. A third (33.3%) of affected hip joints underwent total hip arthroplasty up to 5 years from core decompression. SLE patients with a history of receiving bisphosphonate were 83.2% less dissatisfied with their joint function than patients without a history of bisphosphonate use (P < 0.02). Of the 23 studied cases, the mean cumulative dose of prednisolone before and after core decompression surgery was 46.41 mg and 14.74 mg respectively. Besides, one case (2.6%) that had a high anti-phospholipid antibodies level during follow-up did not have any radiographic deterioration, and 9 cases (23.1%) had some degrees of radiographic deterioration. CONCLUSIONS: The patients group that used bis-phosphonate, had a higher level of satisfaction with joint function after core decompression. Patients with high-level anti-phospholipid antibodies are related to a poor prognosis after core decompression.

The frailty-driven predictive model for failure to rescue among patients who experienced a major complication following cervical decompression and fusion: an ACS-NSQIP analysis of 3,632 cases (2011-2020).

BACKGROUND CONTEXT: Preoperative risk stratification for patients considering cervical decompression and fusion (CDF) relies on established independent risk factors to predict the probability of complications and outcomes in order to help guide pre and perioperative decision-making. PURPOSE: This study aims to determine frailty's impact on failure to rescue (FTR), or when a mortality occurs within 30 days following a major complication. STUDY DESIGN/SETTING: Cross-sectional retrospective analysis of retrospective and nationally-representative data. PATIENT SAMPLE: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried for all CDF cases from 2011-2020. OUTCOME MEASURES: CDF patients who experienced a major complication were identified and FTR was calculated as death or hospice disposition within 30 days of a major complication. METHODS: Frailty was measured by the Risk Analysis Index-Revised (RAI-Rev). Baseline patient demographics and characteristics were compared for all FTR patients. Significant factors were assessed by univariate and multivariable regression for the development of a frailty-driven predictive model for FTR. The discriminative ability of the predictive model was assessed using a receiving operating characteristic (ROC) curve analysis. RESULTS: There were 3632 CDF patients who suffered a major complication and 7.6% (277 patients) subsequently expired or dispositioned to hospice, the definition of FTR. Independent predictors of FTR were nonelective surgery, frailty, preoperative intubation, thrombosis or embolic complication, unplanned intubation, on ventilator for >48 hours, cardiac arrest, and septic shock. Frailty, and a combination of preoperative and postoperative risk factors in a predictive model for FTR, achieved outstanding discriminatory accuracy (C-statistic = 0.901, CI: 0.883-0.919). CONCLUSION: Preoperative and postoperative risk factors, combined with frailty, yield a highly accurate predictive model for FTR in CDF patients. Our model may guide surgical management and/or prognostication regarding the likelihood of FTR after a major complication postoperatively with CDF patients. Future studies may determine the predictive ability of this model in other neurosurgical patient populations.

[Neurovascular decompression in trigeminal neuralgia: Functional outcome]. / Descompresión neurovascular en neuralgia trigeminal: resultado funcional.

INTRODUCTION: The most frequent pathology of the fifth cranial nerve is trigeminal neuralgia (TN), characterized by unilateral orofacial pain, of a paroxysmal nature, with distribution in one or more divisions of the trigeminal nerve. The main objective of this work is to demonstrate the efficacy and safety of neurovascular decompressive surgery (NVD). METHODS: Retrospective analytical study, patients operated on for NVD by TN (n: 155), from January 2006 - 2022, using a retrosigmoid approach and clinicalradiological follow-up, whose intraoperative recording was in 3D system (n: 42). RESULTS: 83.3% (n=35) presented classic NT and 16.7% (n = 7) idiopathic. The right side prevailed with 59.5% (n = 25) and paroxysmal pain with 81% (n=34) of representation in the entire series. Compression of arterial origin represented 76.2% (n: 32) of the cases, the superior cerebellar artery represented the first cause of neurovascular compression (NVC) in 52.4% (n: 22) in the exit zone of the trigeminal nerve. The validity of the magnetic resonance imaging (MRI) protocol selected for this series was analyzed; evidencing a high sensitivity of MRI with 97%, and a specificity of 86%. CONCLUSION: The sensitivity and specificity of highdefinition MRI studies and with special protocols for the evaluation of TN, as gold standard paraclinical, were presented. The DNV offered safe results, a high percentage of the patients were described as successful. The 3D recording allowed retrospective analysis with a vision identical to that of the surgeon during the intraoperative period, the type of NVC.

Introducción: La afección más frecuente del V nervio craneal es la neuralgia del trigémino (NT), se caracteriza por dolor orofacial unilateral, paroxístico, distribuyéndose en una o más divisiones del nervio trigémino. El objetivo de presente trabajo es demostrar la eficacia y seguridad de la cirugía descompresiva neurovascular (DNV). Métodos: Estudio analítico retrospectivo, pacientes intervenidos para DNV por NT (n: 155), desde enero de 2006 - 2022, mediante un abordaje retrosigmoideo y seguimiento clínico-radiológico, cuyo registro intraoperatorio fue en sistema 3D (n: 42). Resultados: 83.3% (n=35) presentó NT clásica y 16.7% (n = 7) idiopática. La mayoría con afectación del lado derecho 59.5% (n = 25) y el dolor paroxístico con 81% (n = 34). La compresión de origen arterial representó 76.2% (n: 32) de los casos, la arteria cerebelosa superior representó la primera causa de compresión neurovascular (CNV) en un 52.4% (n:22) en la zona de salida del nervio trigémino. Se analizó la validez del protocolo de resonancia magnética (RM) seleccionado para esta serie; evidenciando una alta sensibilidad de la RM con 97%, y una especificidad del 86%. Conclusión: Se demostró la sensibilidad y especificidad de los estudios de resonancia magnética (RM) de alta definición y con protocolos especiales para la evaluación de la NT, como paraclínico estándar de oro. La DNV ofreció resultados seguros, un alto porcentaje de los pacientes se calificaron como exitosos. El registro 3D permitió analizar en retrospectiva con una visión idéntica a la del cirujano durante el intraoperatorio, el tipo de CNV.

Percutaneous Radiofrequency Disc Decompression: A Study of 27 Patients.

BACKGROUND: Percutaneous radiofrequency nucleoplasty is a true minimally invasive technique for treatment for radiculopathy caused by contained disc protrusions. This minimally invasive procedure uses controlled thermoablation for reducing the intervertebral disc and decompressing the lumbar nerve root. Material and Methods: Our study is a prospective analysis of 27 patients aged from 30 to 64 years with lumbar disc protrusion who were treated with percutaneous radiofrequency disc decompression (PRFD) between May 2018 and May 2019. Clinical follow-up was reported at 1 month, 3 months, and 6 months. The outcomes were assessed using a visual analog scale (VAS) and MacNab score. RESULTS: Of the 27 patients, 14 were female and 13 were male. Their mean age was 53 ± 2 years. In all 27 patients, percutaneous radiofrequency nucleotomy was performed. An excellent outcome as reflected by MacNab score was observed in 17 patients (63%), a good outcome in 8 patients (29.7%), and a poor outcome in 2 patients (7.3%). Prior to treatment, the average back and leg VAS scores were 7.95 and 7.82, respectively. At sixth month follow-up, the back and leg VAS scores were reduced to 3.17 and 3.04, respectively. Patients with a poor outcome developed early recurrent disc prolapse and required endoscopic discectomy. CONCLUSION: PRFD is a safe and effective treatment of contained disc protrusion. PRFD is a good alternative to surgery. These procedures significantly increase quality of life in patients with lumbar radiculopathy.

Descompressão de cisto dentígero na maxila / Decompression of a maxillary dentigerous cyst

This study describes the case of a dentigerous cyst in a six-year-old patient treated by decompression of the lesion. The patient?s main clinical complaint was facial asymmetry with displacement of the nasal cavity. Clinical examination showed an extensive lesion in the left side of maxilla invading the nasal cavity. An interdisciplinary course of treatment for this patient was indicated to preserve the impacted permanent tooth inside the lesion. A panoramic radiograph and computed tomography scan were requested for planning the surgery. A decompression surgery was performed and an incisional biopsy revealed the presence of a dentigerous cyst in the maxilla. A second operation was performed two years later to disimpact the permanent incisor and promote its eruption by means of orthodontic traction. The patient was thoroughly followed for a few years. Bone repair at the dentigerous cyst site was perfect.

Este artigo relata o caso de um cisto dentígero em um paciente de seis anos de idade em que a técnica utilizada para tratamento foi a de descompressão. A queixa clínica principal do paciente era assimetria facial e deslocamento da cavidade nasal. Ao exame clínico pôde-se constatar uma lesão extensa na maxila, do lado esquerdo que invadia a cavidade nasal. Foi planejado um tratamento interdisciplinar com a finalidade de preservar o dente permanente impactado que se localizava no interior da lesão. Foram requisitadas para o diagnóstico e planejamento cirúrgico uma radiografia panorâmica e uma tomografia computadorizada. A cirurgia de descompressão foi inicialmente realizada e a biópsia incisional revelou a presença de um cisto dentígero na maxila. A segunda intervenção cirúrgica foi realizada após dois anos, com a finalidade de tracionar o incisivo permanente para permitir que o mesmo pudesse irromper na cavidade bucal por meio de tração ortodôntica. O paciente foi rigorosamente acompanhado por alguns anos e pôde-se observar uma perfeita reparação óssea na área em que havia o cisto dentígero.

Comportamiento de la enfermedad por descompresión inadecuada en los buzos mariscadores de Quellón durante los seis últimos años (1985-1991) / Behavior of the disease caused by inadequated decompression in the divers of Quellón during the last 6 years (1985-1991)

Se realiza un estudio descriptivo de todos los casos de Enfermedad por Descompresión Inadecuada (E.D.I.), desde el primero de abril de 1985 al 31 de marzo de 1991, clasificándolos según el modelo de Golging et.al y registrando los datos en las fichas elaboradas por el Dr. Alfredo Cea Egaña. Se analizaron 125 casos, destacando que el 41 por ciento de ellos corresponde a formas graves de E.D.I., los que junto al número total de casos se incrementó hasta 1988, fecha desde la cual ha disminuído su importancia, debido a varios factores. La etiopatogenia es multifactorial y a pesar de su polimorfismo clínico es fácilmente diagnosticable, radicando su importancia en que afecta a una población en edad reproductiva, es totalmente prevenible y de buen pronóstico, con un tratamiento adecuado y oportuno

Incidentes fisiológicos durante entrenamiento en cámara hipobárica entre los años 1983-1992 / Physiological training in altitude chamber in the chilean airforce: years 1983-1992

En el presente trabajo, se ha analizado el Programa de Entrenamiento Fisiológico en el Departamento de Medicina Aeroespacial de la Dirección de Sanidad de la Fuerza Aérea de Chile, en lo que respecta a incidentes producidos durante el desarrollo de dicho programa y al que fueron sometidos tanto pilotos alumnos como instructores de vuelo de cámara hipobárica, durante los años 1983-1992. En este período se entrenó a 2.118 alumnos en vuelos de hipoxia y vuelos de descompresión rápida no registrándose ningún accidente, teniendo presente además, que los incidentes que se produjeron fueron sin consecuencias graves, tanto para alumnos como instructores. En el período analizado se produjeron un total de 274 incidentes en los alumnos correspondiendo a barotitis, barotitis tardía y barosinusitis, los porcentajes más altos. Asimismo, en los instructores el número total de incidentes fue de 56, siendo barotitis, barotitis tardía y barosinusitis los más frecuentes. Otros hechos importantes son la realización de 23 vuelos médicos y de 24 vuelos de prueba, todos sin consecuencia y con resultados altamente positivos. Cabe destacar que durante este período los incidentes han sido superados efectiva y oportunamente gracias a la preparación, capacidad y a las medidas de seguridad que en cada circunstancia específica se aplicaron