Evaluation of the accuracy of three-dimensionally printed patient-specific guides for transsphenoidal hypophysectomy in small-breed dogs

Abstract

OBJECTIVE To assess the accuracy of transsphenoidal hypophysectomy using 3-D printed patient-specific guides (3D-PSGs) in small-breed dogs. ANIMALS Heads obtained from the cadavers of 19 small-breed dogs (ex vivo portion of study) and 3 healthy adult (3 to 4 years) purpose-bred Beagles with a median body weight of 9.2 kg. PROCEDURES In the ex vivo study, CT images of the cadavers were collected. The position, width, and length of the pituitary fossa and the pilot hole (insertion angle and place) were measured. Using PSGs, 19 pilot holes were made for the pituitary gland fossa, and CT was performed to assess the position accuracy. In the in vivo study, 3 surgical windows from the pilot holes were made using PSGs. Repeated CT and MRI were performed to evaluate the safeness and effectiveness of PSGs, followed by necropsy. RESULTS In the ex vivo study, the median (interquartile range) difference between the pre- and postoperative insertion angles was 2° (0° to 3.5°) and the median deviation of the pilot hole was 0.46 mm (0 to 1.58 mm). In the in vivo study, the surrounding structures were not damaged, and favorable outcomes were evident in terms of the shape, size, and position of the surgical window. CLINICAL RELEVANCE 3D-PSGs provided a safe and effective surgical window for transsphenoidal hypophysectomy. Our findings emphasized the applicability of PSGs in brain surgery, in terms of accuracy and effectiveness.

A 3-Dimensional Printed Patient-Specific Surgical Guide to Facilitate Transsphenoidal Hypophysectomy in Dogs

“…A recent study from colleagues in Korea, using experimental dogs under 8.5 kg, performed coincidentally and in parallel to ours, also reports that a 3D surgical guide for transsphenoidal hypophysectomy provides an accurate reading of the entry point into the outer cortical layer of the basisphenoid bone (24). These authors have not tested their device in companion dogs affected by pituitary dependent-hyperadrenocorticism (24). They focus on the accuracy of a single pilot hole indicating the center of the sella turcica that is later extended in a rectangular shape in cranio-caudal and latero-lateral directions (24).…”

“…These authors have not tested their device in companion dogs affected by pituitary dependent-hyperadrenocorticism ( 24 ). They focus on the accuracy of a single pilot hole indicating the center of the sella turcica that is later extended in a rectangular shape in cranio-caudal and latero-lateral directions ( 24 ). The pre-operative planned measures were 6 mm in width and 8 mm in length, and the post-operative measures had a median of 5.17 mm width and 7.51 mm length, therefore similar to the precision we achieved ( 24 ).…”

“…Historically, hypophysectomy via an intracranial transtemporal route was used in experimental dogs but was later replaced by the transsphenoidal route ( 3 ). Reported transsphenoidal techniques in experimental “normal” dogs include: (i) the placement of three small self-threading screws in the basisphenoid bone used as radiographic markers and followed by cranial sinus venogram outlining the sella turcica ( 16 ); (ii) a ventral paramedian approach using CT images obtained with the tip of a radiopaque feeding tube placed in the nasopharynx near the hamuli processes ( 10 ); (iii) the use of a stereotactic neuro-navigation system ( 27 ); and (iv) the use of a 3D surgical guide using CT and MRI images for the design and planning of the device ( 24 ). In practise, the reported transsphenoidal techniques in pet dogs with pituitary dependent hyperadrenocorticism include: (i) using anatomical landmarks such as the hamuli processes and emissary vein; and (ii) placement of pilot holes in the outer cortical layer of the basisphenoid bone followed by CT imaging ( 4 , 12 , 14 , 20 ).…”

Novel transforaminal approach allows surgical decompression of an atlantoaxial band in dogs: a cadaveric study and clinical cases

“…A visualization system was used to improve the visualization of the surgical field (Figure 4). 33 Next, an incision on the dorsal AA membrane was made on the more compressed section. A 10-mm, 0° rigid laparoscope (autoclavable laparoscope; Stryker) was used and attached to a high-definition camera system (Stryker Endoscopy) when using the endoscopic system to magnify the surgical site.…”

Endoscopy-assisted resection of a sphenoid-wing meningioma using a 3D-printed patient-specific pointer in a dog: A case report

“…Both were printed using the RS6000 3D printer (Uniotech, Shanghai, China) according to a previously described protocol (20). Printing and sterilization of the 3D bone models and the PSP prior to the real surgery required ∼1 day (20). The surgical procedure was based on sphenoid-wing craniectomy (22)(23)(24).…”