Awake mouse brain photoacoustic and optical imaging through a transparent ultrasound cranial window

Optical resolution photoacoustic microscopy (OR-PAM) can map the cerebral vasculature at capillary level resolution. However, the OR-PAM setup’s bulky imaging head makes awake mouse brain imaging challenging and inhibits its integration with other optical neuroimaging modalities. Moreover, the glass cranial windows used for optical microscopy are unsuitable for OR-PAM due to the acoustic impedance mismatch between the glass plate and the tissue. To overcome these challenges, we propose a lithium niobate based transparent ultrasound trans-ducer (TUT) as a cranial window on a thinned mouse skull. The TUT cranial window simplifies the imaging head considerably due to its dual functionality as an optical window and ultrasound transducer. The window remains stable for six weeks, with no noticeable inflammation and minimal bone regrowth. The TUT window’s potential is demonstrated by imaging the awake mouse cerebral vasculature using OR-PAM, intrinsic optical signal imaging and two-photon microscopy. The TUT cranial window can potentially also be used for ultrasound stimulation and simultaneous multimodal imaging of the awake mouse brain.

Innovative Biomaterials for Bone Regrowth

The regenerative medicine, a new discipline that merges biological sciences and the fundamental of engineering to develop biological substitutes, has greatly benefited from recent advances in the material engineering and the role of stem cells in tissue regeneration. Regenerative medicine strategies, involving the combination of biomaterials/scaffolds, cells, and bioactive agents, have been of great interest especially for the repair of damaged bone and bone regrowth. In the last few years, the life expectancy of our population has progressively increased. Aging has highlighted the need for intervention on human bone with biocompatible materials that show high performance for the regeneration of the bone, efficiently and in a short time. In this review, the different aspects of tissue engineering applied to bone engineering were taken into consideration. The first part of this review introduces the bone cellular biology/molecular genetics. Data on biomaterials, stem cells, and specific growth factors for the bone regrowth are reported in this review.

A Five Years Prospective Study of Dentigerous Cyst

The purpose of this 5-year study (2002-2007) was to evaluate 90 cases of dentigerous cysts that were identified in a private dental office in terms of distribution by region (maxillary-anterior region, mandibular), age, sex, and surgical removal technique chosen. We also compared the 45 cases where PRGF was applied after cyst extirpation with the other 45 cases that were allowed to heal periosteum. We noticed that in cases where the PRGF clot was applied in the cystic geography, bone regrowth was achieved much faster.

Marsupialization Followed by Curettage of an Extensive Periapical Cyst in the Incisive and Maxillary Bone in a Dog

A 7-year-old male intact border terrier (8.5 kg) was presented with a large, painless mass apical to the right maxillary incisors. Diagnostic imaging and histopathology confirmed the diagnosis of periapical cyst due to a nonvital maxillary incisor. Extensive cysts are often multilocular and therefore difficult to debride without risk of iatrogenic damage. Complete resection can cause damage to adjacent structures and may compromise function. Due to the large size of the cyst, it was decided to perform staged treatment with extraction of the nonvital tooth and marsupialization. Following marsupialization, gradual bone regrowth caused size reduction. The stoma from the marsupialization was kept open for 8.5 months before the cyst was curetted and the wound closed. Complete obliteration of the cyst cavity was seen at short- and long-term follow-up examinations (7 and 24 months after curettage, respectively).

Medium-Term Outcome and CT Assessment of Lateral Foraminotomy at the Lumbosacral Junction in Dogs with Degenerative Lumbosacral Stenosis

Objective This article aims to report the medium-term clinical outcome and assess persistence of enlargement of the lumbosacral lateral intervertebral neurovascular foramen using computed tomography (CT) volumetric analysis in dogs following lateral foraminotomy. Materials Six dogs that underwent lumbosacral lateral foraminotomy on one or both sides were evaluated with CT prior to, immediately postoperatively (n = 2) and at 12 to 44 months of follow-up. Five out of six dogs had successful clinical outcomes with alleviation of pain and increased levels of activity, according to subjective assessment. Immediate postoperative CT volumetric analysis of the lateral intervertebral neurovascular foramina in two dogs indicated a 650 to 800% increase in volume in extension achieved by foraminotomy (four foramens). At subsequent follow-up, bone regrowth had occurred with reduction in foraminal volume, though in both dogs foraminal volume remained higher than preoperative values. Follow-up CT at a median of 24 months postoperatively indicated a mean 335% increase in volume of the lumbosacral lateral intervertebral neurovascular foramina in extension compared with the preoperative foraminal volume. The follow-up volume was substantially greater than the presurgical volume in four out of six dogs. Clinical Significance In this limited case series, lateral foraminotomy achieved persistent enlargement of the lumbosacral lateral intervertebral neurovascular foramen in the medium term, but osseous regrowth at the site was demonstrated which may limit the effectiveness of lateral foraminotomy in the longer term. One of two working dogs had recurrent clinical signs that necessitated further surgery.

Clinical and Radiological Outcomes after Microscopic Bilateral Decompression via a Unilateral Approach for Degenerative Lumbar Disease: Minimum 5-Year Follow-Up

<sec><title>Study Design</title><p>A retrospective study.</p></sec><sec><title>Purpose</title><p>To assess postoperative bone regrowth at surgical sites after lumbar decompression with &gt;5 years of follow-up. Postoperative preservation of facet joints and segmental spinal instability following surgery were also evaluated.</p></sec><sec><title>Overview of Literature</title><p>Previous reports have documented bone regrowth after conventional laminectomy or laminotomy and several factors associated with new bone formation.</p></sec><sec><title>Methods</title><p>Forty-nine patients who underwent microscopic bilateral decompression via a unilateral approach at L4–5 were reviewed. Primary outcomes included correlations among postoperative bone regrowth, preservation of facet joints, radiographic parameters, and clinical outcomes. Secondary outcomes included comparative analyses of radiographic parameters and clinical outcomes among preoperative diagnoses (lumbar spinal stenosis, degenerative spondylolisthesis, and degenerative lumbar scoliosis).</p></sec><sec><title>Results</title><p>The average value of bone regrowth at the latest follow-up was significantly higher on the dorsal side of the facet joint (3.4 mm) than on the ventral side (1.3 mm). Percent facet joint preservation was significantly smaller on the approach side (79.2%) than on the contralateral side (95.2%). Bone regrowth showed a significant inverse correlation with age, but no significant correlation was observed with facet joint preservation, gender, postoperative segmental spinal motion, or clinical outcomes. Subanalysis of these data revealed that bone regrowth at the latest follow-up was significantly greater in patients with degenerative lumbar scoliosis than in those with lumbar spinal stenosis. Postoperative segmental spinal motion at L4–L5 did not progress significantly in patients with degenerative spondylolisthesis or degenerative lumbar scoliosis compared with those with lumbar spinal stenosis.</p></sec><sec><title>Conclusions</title><p>Microscopic bilateral decompression via a unilateral approach prevents postoperative spinal instability because of satisfactory preservation of facet joints, which may be the primary reason for inadequate bone regrowth. Postoperative bone regrowth was not related to clinical outcomes and postoperative segmental spinal instability.</p></sec>