Saving the Exposed Deep Brain Stimulation Implant: A Comprehensive Review of Implant Extrusion and Reconstructive Options.

INTRODUCTION: Deep brain stimulation (DBS) for the treatment of Parkinson disease is susceptible to complications, such as hardware extrusion, most commonly at the scalp and chest. The authors describe their experience with the management of hardware extrusion and reconstruction with one of the largest single-institution experience and suggest an evidence-based treatment algorithm for the management of such cases. METHODS: A retrospective review of hospital records was performed to identify patients who underwent DBS-related surgery and reconstruction from January 2015 to April 2020. Management of these patients involved culture-directed antibiotics, local wound debridement, various forms of reconstruction, and hardware removal when indicated. RESULTS: Ninety-four patients with 131 DBS-related procedures were included. Twelve patients (12.8%) had hardware extrusion, of which 6 occurred primarily at the scalp and 6 occurred primarily at the chest. Primary closure of scalp wounds (odds ratio, 0.05 [0.004-0.71], P = 0.035) was negatively associated with treatment success. The type of reconstruction of chest wounds did not affect its success ( P = 0.58); however, none of them involved a new surgical bed, such as contralateral or hypochondrial placement. CONCLUSIONS: Hardware extrusion is a significant complication of DBS-related surgery. Management of extrusion at the scalp should involve the use of tension-free, well-vascularized locoregional flaps as opposed to primary closure. Implantable pulse generator extrusions at the chest can be managed with both primary closure and repositioning in a new surgical bed. Extruded DBS implants may be salvaged with appropriate reconstructive considerations, and the authors suggest an evidence-based treatment algorithm.

A novel technique for atraumatic transurethral catheterisation of male rats.

Transurethral catheterisation of male rats is technically difficult owing to anatomical peculiarities. In the male rat, the urethral striated sphincter consists of two lateral fascicles separated by an anterior and a posterior strip of connective tissue, which impedes the smooth insertion of a urinary catheter. For rat studies requiring continuous collection of urine, bladder irrigation, or measurement of bladder pressure, investigators either have to exclude the male population (be limited to the female population) or perform percutaneous (suprapubic) bladder puncture in male rats, which is more traumatic and invasive than transurethral catheterisation. This paper describes a novel, atraumatic method of transurethral catheterisation in the male rat, with the aid of a microscope and microsurgical instruments. Six Wistar rats were used for this experiment, all of which were catheterised successfully, with no evidence of bladder or urethral injury. The study shows that male rats can be safely catheterised via the urethra with the aid of a microscope and microsurgical instruments for both visual and tactile feedback. This is a relatively straightforward technique to learn and can allow for inclusion of male rats in future studies requiring urinary analysis or bladder irrigation, without the need for traumatic percutaneous (suprapubic) bladder puncture.

Primary thrombolysis for free flap surgery in head and neck reconstruction: a case report and review.

The use of free flaps is an essential and reliable method of reconstruction in complex head and neck defects. Flap failure remains the most feared complication, the most common cause being pedicle thrombosis. Among other measures, thrombolysis is useful when manual thrombectomy has failed to restore flap perfusion, in the setting of late or established thrombosis, or in arterial thrombosis with distal clot propagation. We report a case of pedicle arterial thrombosis with distal clot propagation which occurred during reconstruction of a maxillectomy defect, and was successfully treated with thrombolysis using recombinant tissue plasminogen activator. We also review the literature regarding the use of thrombolysis in free flap surgery, and propose an algorithm for the salvage of free flaps in head and neck reconstruction.

Dermointegration in the exposed titanium cranioplasty: a possible protective phenomenon.

Implant exposure is a known complication of titanium mesh cranioplasty and is usually managed by implant removal and/or exchange. We describe a case of exposed titanium mesh cranioplasty which was managed with implant exchange and bipedicled flap coverage, and showcase an interesting phenomenon of full-thickness skin present beneath the exposed mesh. This was confirmed on histopathology, which showed the presence of dermal appendages including pilosebaceous units and eccrine glands. We postulate that the mechanism behind this phenomenon involves islands of viable skin 'dropping' between holes in the mesh and coalescing beneath the exposed implant, as suggested by histopathology findings of nodular protrusions and varying degrees of epidermal hyperplasia. This protects the underlying dura from external infection. We propose for this phenomenon to be called dermointegration. Our findings suggest that similar cases, particularly patients who are not fit for general anaesthesia, may potentially be managed with a more conservative approach.