Biomedical subjects

Allen Carl

Publications and source records attributed to Allen Carl.

4 recordsLinked to original sources

PubMed2005

The effect of pinealectomy on scoliosis development in young nonhuman primates.

STUDY DESIGN: Prospective study on pinealectomy in primates. OBJECTIVE: To evaluate whether pinealectomy in a bipedal nonhuman primate model will result in the development of scoliosis. SUMMARY OF BACKGROUND DATA: Pinealectomy in newborn chickens consistently resulted in scoliosis development. Published data suggest that the surgical removal of the pineal, loss of melatonin secretion, and a bipedal posture are important elements in the development of scoliosis in lower animal models. METHOD: There were 18 rhesus monkeys between 8 and 11 months old that underwent pineal excision. All monkeys were kept in a regulated 12-hour light-dark cycle. Monthly radiographs assessed scoliosis development. Completeness of pineal excision was assessed by measurement of a major metabolite of melatonin in the urine, 6-sulfatoxymelatonin, using an enzyme-linked immunosorbent assay assessed. RESULTS: Mean follow-up was 28 months (range 10-41). Seven monkeys died prematurely, and 11 survived to date; the data from those that died could still be used, although follow-up was shortened. At the latest follow-up or death, scoliosis did not develop in any of the monkeys. Urinary 6-sulfatoxymelatonin measurements revealed 3 patterns. Group 1 consisted of 10 monkeys, which showed definite evidence of complete pineal excision. Group 2 consisted of an uncertain group of 2 monkeys in which the nighttime melatonin level is slightly high. Group 3 consisted of 6 monkeys that had incomplete pineal excision or ectopic melatonin production. CONCLUSIONS: To our knowledge, this is the first report of pinealectomy in nonhuman primates. Of the 18 monkeys, 10 had a loss of melatonin secretion, for a mean of 29 months after surgery. Because none of the monkeys had scoliosis develop, this study strongly suggests that the possible etiologic factors producing idiopathic scoliosis in lower animals are different from primates, and findings in lower animals cannot necessarily be extrapolated to human beings.

Animals↗

PubMed2005

Intradiscal therapy: a review of current treatment modalities.

STUDY DESIGN: A systematic review of the medical literature regarding current intradiscal therapeutic methods. OBJECTIVES: To establish an understanding of the current intradiscal treatment options for the management of low back pain. SUMMARY OF BACKGROUND DATA: Current treatment of intradiscal disease is rapidly evolving and as such should be a multidisciplinary effort that follows a logical, orderly algorithm. Minimally invasive techniques, namely, intradiscal electrothermal therapy (IDET), radiofrequency ablation (RFA), percutaneous endoscopic laser discectomy (PELD), and cryoablation have challenged the conventional surgical management of back pain. METHODS: Thirty-eight research reports, published between 1986 and 2005, were systematically reviewed for disease classification, surgical intervention, and treatment outcomes (neurologic status, pain scores, and ambulation). RESULTS: The surgical literature on the management of intradiscal disease continues to be limited to large series with short clinical follow-ups. Arthrodesis continues to be the primary treatment modality in the majority of patients. Newer treatment options including IDET, RFA, PELD, and cryoablation have shown promising results with regards to symptomatic relief and early return to function. CONCLUSION: Low back pain is an extremely common and potentially debilitating problem. Adding biophysical methods to well-tested biomechanical and newly investigated biomolecular solutions allows for multiple avenues of therapeutic interventions. With future clinical and basic science studies regarding intradiscal therapies forthcoming, we may soon alter our current treatment algorithms for the management of discogenic back pain.

Catheter Ablation↗

PubMed2004

New percutaneous access method for minimally invasive anterior lumbosacral surgery.

Preliminary cadaver, animal, and human studies were performed to determine the feasibility of axial anterior lumbosacral spine access using a percutaneous, presacral approach. Custom instruments were directed under fluoroscopic guidance along the midline of the anterior sacrum to the surface of the sacral promontory where an axial bore was created into the lower lumbar vertebral bodies and discs. Imaging and gross dissection were performed in cadavers and animals. The procedure was used for lumbosacral biopsy in human subjects guided by intraoperative imaging and clinical monitoring. All procedures were technically successful. This study demonstrates the feasibility of the axial access technique to the anterior lower lumbar spine.

Animals↗

PubMedDate not supplied

New developments in nucleus pulposus replacement technology.

Attempts to alleviate the pain attributed to degeneration of the nucleus pulposus using replacement or reinforcement techniques dating back to the 1950s are reviewed. The various materials and their insertion techniques are discussed as are results available from early clinical experiences. These techniques are in evolution and clinical outcomes will be necessary to establish the efficacy of these approaches.

Arthroplasty, Replacement↗