Recent Advances In Surgery 34 Pdf Free Download [PORTABLE]
DOWNLOAD - https://urloso.com/2sZlPy
The pedunculopontine nucleus has recently been trialled as a new target for DBS, particularly for the gait problems seen in PD. While initial trials reported positive impacts on gait and postural instability, more rigorous subsequent trials were less promising, in part because of variability in the anatomical definition of the pedunculopontine nucleus in the human brain, suboptimal programming settings, and low patient numbers61,98. More recently, stimulation of the substantia nigra reticularis has shown promising effects on axial symptoms in preliminary studies99 along with stimulation of the basal forebrain (with STN) for some of the cognitive deficits in PD100. In another pilot study, thoracic spinal cord stimulation significantly reduced the frequency of freezing episodes in patients with advanced PD, with trials ongoing101.
Despite aggressive management consisting of maximal safe surgical resection followed by external beam radiation therapy (60 Gy/30 fractions) with concomitant and adjuvant temozolomide, approximately 90% of WHO grade IV gliomas (glioblastomas, GBM) will recur locally within 2 years. For patients with recurrent GBM, no standard of care exists. Thanks to the continuous improvement in radiation science and technology, reirradiation has emerged as feasible approach for patients with brain tumors. Using stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT), either hypofractionated or conventionally fractionated schedules, several studies have suggested survival benefits following reirradiation of patients with recurrent GBM; however, there are still questions to be answered about the efficacy and toxicity associated with a second course of radiation. We provide a clinical overview on current status and recent advances in reirradiation of GBM, addressing relevant clinical questions such as the appropriate patient selection and radiation technique, optimal dose fractionation, reirradiation tolerance of the brain and the risk of radiation necrosis.
Glioblastoma (GBM) is the most common malignant brain tumor in adults. The standard treatment includes surgery followed by external beam radiation therapy (RT) with concomitant and maintenance temozolomide, with a reported median survival time of 14.6 months and 2-year survival rate of 26.5%, respectively [1]. However, almost all GBMs relapse within or in close proximity to the initial site of disease despite advances in surgery and chemoradiotherapy.
Reirradiation is increasingly used in patients with recurrent GBM. Even though damage of normal brain tissue previously treated with high dose RT is of concern, technological advances in radiation techniques, including developments in treatment planning systems and dose delivery, have improved the therapeutic ratio making it possible to use reirradiation as feasible treatment option [8]. Variable median survival times of 6 to 12 months and neurological toxicity rates of 5% to 20% have been reported after stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT), using either hypofractionated or conventionally fractionated radiation schedules [9, 10]. In addition, survival benefit has been reported following reirradiation in combination with temozolomide or bevacizumab compared to reirradiation alone. We present a clinical overview on the current status and advances of reirradiation in the setting of recurrent or progressive GBM after standard treatment, with special regard to target volume delineation and impact of radiation techniques on survival and risk of radiation-induced brain necrosis.
To address these limitations, we bioengineered a cell-free implantable medical device as a substitute for human corneal stromal tissue. As a raw material we used natural type I collagen, the main protein in the human cornea24. For an abundant yet sustainable and cost-effective supply of collagen, we used medical-grade collagen sourced from porcine skin, a purified byproduct from the food industry already used in FDA-approved medical devices for glaucoma surgery25 and as a wound dressing26. In a previous clinical study27,28, we evaluated implants engineered from recombinant human collagen that had several limitations: the collagen could be produced only in small quantities, implants were mechanically weak and required invasive suturing, implants were not evaluated for long-term stability, and surgery was invasive and led to a strong wound-healing response and partial implant melting. Here we addressed these limitations by using type I medical-grade porcine dermal collagen, developing a new method of double crosslinking to improve implant strength and stability, and using a new minimally invasive surgical implantation technique to promote corneal thickening, reshaping and rapid wound healing.
Because of partial thinning and haze from suturing the access cut in the minipig model, we reverted to a suture-free implementation of FLISK29,31 with smaller access cuts to minimize complications in human subjects. Avoidance of sutures in FLISK removes additional barriers to implementation of the surgery in LMICs, circumventing issues of time, cost, suture-induced refractive errors and the need for additional hospital visits for subsequent suture adjustment and removal. In human subjects with advanced keratoconus but without scarring, we did not remove native corneal tissue and only added the BPCDX, simplifying the surgery to a single lamellar cut and access cut (Supplementary Fig. 3). Femtosecond laser-assisted surgery was used to ensure accuracy and reproducibility, but intrastromal pocket creation can be achieved manually without a laser45,46.
While previous clinical studies focus on human donor tissue, bioengineering implantable tissue is the key to addressing the global burden of corneal blindness. A growing number of bioengineered materials are being evaluated in animal models, but to date only a few have reached human studies. A summary of recent clinical and preclinical studies of corneal bioengineering technologies is given in Supplementary Table 4. Most clinical studies, while having achieved significant advances in biomaterial properties, have addressed relatively rare causes of corneal blindness such as chemical burns54,55, infections55,56,57,58, ulcers59 or high-risk cases54,55 with the goal to stabilize the condition and avoid blindness, but not to optimize vision. Only two clinical studies to date have addressed keratoconus, a condition that impairs millions globally, aiming to provide vision gains comparable to standard PK or DALK. One approach, while innovative and promising, still requires human donor tissue, tissue banking and additional liposuction surgery34, and has to date provided limited corneal thickening, flattening and BCVA gain. The other study, conducted by several of the present authors27,28, failed to thicken the cornea or provide complete transparency, with the biomaterial unable to withstand enzymatic degradation. Moreover, the implants in that study were not packaged, tested for shelf life or full ISO compliance, and surgery led to suture-related complications, scarring and an uneven corneal surface.
In this article we review recent advances made in the pathophysiology, diagnosis, and treatment of inhalation injury. Historically, the diagnosis of inhalation injury has relied on nonspecific clinical exam findings and bronchoscopic evidence. The development of a grading system and the use of modalities such as chest computed tomography may allow for a more nuanced evaluation of inhalation injury and enhanced ability to prognosticate. Supportive respiratory care remains essential in managing inhalation injury. Adjuncts still lacking definitive evidence of efficacy include bronchodilators, mucolytic agents, inhaled anticoagulants, nonconventional ventilator modes, prone positioning, and extracorporeal membrane oxygenation. Recent research focusing on molecular mechanisms involved in inhalation injury has increased the number of potential therapies.
In this review we describe the recent advances made in our understanding of the pathophysiology of inhalation injury, diagnostic criteria and injury severity, complications, current treatment options, and future avenues of research. 2b1af7f3a8
