J Vet Clin 27(5) : 584-587 (2010)

Coexistence of Sciatic, Dorsal, and Caudal Perineal in a

Hun-Young Yoon and Soon-wuk Jeong1 Department of Veterinary Surgery, College of Veterinary Medicine, and the Veterinary Science Research Institute, Konkuk University, Seoul 143-701, Korea

(Accepted: August 23, 2010)

Abstract : A 5-year-old castrated male Chihuahua weighing 1.8 kg was presented for examination of a right perineal swelling. No clinical signs other than the swelling were observed by the owner. Digital palpation to the swelling confirmed right reducible perineal herniation. Dorsal perineal was observed during surgery. A modified internal obturator transposition combined with a modified traditional perineal herniorrhaphy was performed for the perineal hernia repair. Contralateral herniation involving fat was noted a month after surgery. Coexistence of sciatic, dorsal, and caudal perineal hernias was observed during surgery. Aforementioned herniorrhaphy was performed for the perineal hernia repair. The follow-up information was based on physical examination by veterinarian. The owner reported that there was no evidence of complications related to surgery. Key words : perineal hernia, modified internal obturator transposition, modified traditional perineal herniorrhaphy, dog.

Introduction that had been present for approximately a month. No tenesmus, stranguria, or any clinical signs other than the swelling was Perineal hernia results from a weakness, separation, and observed by the owner. On physical examination, digital pal- eventual failure of the muscular pelvic diaphragm that consists pation to the swelling confirmed right reducible perineal of the coccygeal and muscles, with subsequent herniation. Plain radiographs revealed that no pelvic or abdom- displacement of pelvic or abdominal contents into subcuta- inal contents other than the fat were displaced into subcuta- neous perineal region (1,3,17,18). Perineal hernia is most neous perineal region. A diagnosis of right reducible perineal common in older intact male (8,14,15,20). Factors that hernia was made. have been proposed to contribute to the development to of The dog was premedicated for surgery with butorphanol perineal hernia include chronic as a result of rectal (0.4 mg/kg IM) and atropine sulfate (0.02 mg/kg SC), fol- abnormalities, straining to defecate due to prostatomegaly, lowed by anesthetic induction with propofol (6 mg/kg IV). pelvic fracture and increased intra-abdominal pressure, and The dog was intubated and anesthesia was maintained with imbalance of gonadal hormones (10,16,19). Clinical signs asso- isoflurane and oxygen. Lactated Ringer’s solution was admin- ciated with perineal hernia include constipation, obstipation, istered intravenously at a rate of 5 mL/kg/h until completion tenesmus, dyschezia, , stranguira, and skin ulceration of the surgical procedure. The dog received cefazolin (20 mg/ (4,11). Four types of perineal hernia have been described: kg IV) at the time of anesthetic induction. The patient was caudal, dorsal, ventral, and sciatic (15). Caudal perineal hernias placed in a perineal position and the tail was fixed over the are the most common, while sciatic perineal hernias are rare back with tape. The pelvic limbs were secured over the edge (15). To the authors’ knowledge, canine sciatic perineal hernia at the end of the table. In order to prevent fecal contamina- concurrent with dorsal and caudal perineal hernias has not been tion during perineal surgery, a purse string suture was placed reported. This report describes the diagnosis and surgical around the anus and tied to occlude the anus. Prior to tighten- management of sciatic perineal hernia concurrent with dorsal ing the purse string suture, a lubricated gauze tampon was and caudal perineal hernias in a dog. placed in the to contain feces. The surgical approach to the hernia was via a curvilinear right perineal skin incision. Case After blunt dissection through the hernia sac, the hernia content (retroperitoneal fat) was observed to protrude into the A 5-year-old castrated male Chihuahua weighing 1.8 kg was perineal region between the levator ani and coccygeus muscles. presented to the University of Konkuk Veterinary Medical The herniated fat was partially amputated and reduced. The Teaching Hospital for examination of a right perineal swelling pelvic diaphragm structures were identified before closure. Atrophy of the levator ani and coccygeus muscles was ob- 1Corresponding author. served. The hernia was repaired using a modified internal E-mail : [email protected] obturator transposition combined with a modified traditional 584 Coexistence of Sciatic, Dorsal, and Caudal Perineal Hernias in a Dog 585 perineal herniorrhaphy. Complication was noted after surgery. The dog was presented a month after surgery with contra- lateral herniation involving fat. The surgical approach to the hernia was via a curvilinear left perineal skin incision. After blunt dissection through the hernia sac, the hernia contents (retroperitoneal fat) were observed to protrude into the perineal region between the coccygeus and levator ani muscles, be- tween the coccygeus muscle and sacrotuberous ligament, and between the external anal sphincter, levator ani, and internal obturator muscles (Fig 1). The herniated fats were partially amputated and reduced respectively. Atrophy of the levator ani muscle was observed. The hernias were repaired using the modified internal obturator transposition combined with the modified traditional perineal herniorrhaphy (Fig 2). In brief, the origin of the internal obturator muscle including the fascia and periosteum was incised along the caudal border of the ischium. The periosteum and internal obturator muscle were Fig 2. Intraoperative photograph of suture placement. Simple elevated using a periosteal elevator. Simple interrupted sutures interrupted sutures are preplaced in the external anal sphincter muscle (EAS), levator ani muscle (LA), coccygeus muscle (C), (3-0 polyglycolic acid) were preplaced in the external anal and sacrotuberous ligament (SL) for the modified traditional sphincter muscle, levator ani muscle, coccygeus muscle, and technique. Simple interrupted sutures are preplaced in the internal sacrotuberous ligament. Then, simple interrupted sutures (3-0 obturator muscle (IO) with the periosteum and the external anal polyglycolic acid) were preplaced in the internal obturator sphincter muscle and in the internal obturator muscle with the muscle and the external anal sphincter muscle and in the periosteum, levator ani muslc, coccygeus muscle, and sacro- internal obturator muscle, levator ani, coccygeus muscle, and tuberous ligament respectively for the modified internal obturator sacrotuberous ligament respectively. The external anal sphinc- muscle transposition technique. ter muscle was secured to the levator ani muscle, coccygeus muscle, and sacrotuberous ligament. Then, the internal obturator muscle was secured to the external anal sphincter muscle and plications related to surgery such as sciatic nerve injury, rectal the levator ani muslce, coccygeus muscle, and sacrotuberous prolapse, wound dehiscence, or perineal hernia recurrence. ligament respectively to close ventral defect. The subcutane- ous tissues and skin were closed using 3-0 polyglycolic acid Discussion and 3-0 nylon respectively. The follow-up was completed by veterinarian’s physical examination 6 months after the second Four types of canine perineal hernia have been described: surgery. The owner reported that there was no evidence of com- (1) dorsal perineal hernia-herniation between the coccygeus and levator ani muscles; (2) sciatic perineal hernia-herniation between the coccygeus muscle and sacrotuberous ligament; (3) caudal perineal hernia-herniation between the external anal sphincter, levator ani, and internal obturator muscles; and (4) ventral perineal hernia-herniation ventral to the ischioure- thralis muscle, between the bulbocavernosus and ischicavern- osus muscles (15,20). Each type of perineal hernia has been reported occurring independently (5,9,15). In the right perineal region of the case reported here, the hernia content (retroperi- toneal fat) was observed to protrude into the perineal region only between the levator ani and coccygeus muscles; how- ever, in the left perineal region, the hernia content (retroperi- toneal fat) was observed to protrude into the perineal region between the coccygeus and levator ani muscles, between the coccygeus muscle and sacrotuberous ligament, and between Fig 1. Intraoperative photograph in which the partially amputated the external anal sphincter, levator ani, and internal obturator herniated fats are observed to protrude into the perinieal region muscles. The is the region that closes the pelvic between the coccygeus and levator ani muscles (oval), between canal and deeply bounded by the third caudal vertebra dor- the coccygeus muscle and sacrotuberous ligament (dotted oval), sally, the sacrotuberous ligaments bilaterally, and the ischiatic and between the external anal sphincter, levator ani, and internal arch ventrally, including the pelvic diaphragm (7). The pelvic obturator muscles (circle). diaphragm is formed by muscles and fasciae such as the coc- 586 Hun-Young Yoon and Soon-wuk Jeong cygeal and levator ani muscles and superficial and deep would have been indicated; however, the modified traditional perineal fasciae (7). A weakness of the pelvic diaphragm herniorrhaphy combined with the modified internal obturator results in displacement of pelvic or abdominal contents into muscle transposition was performed because the levator ani subcutaneous perineal region. Hormonal or neurogenic influ- and coccygeus muscles were severely atrophic and the caudal ences have been implicated in weakening the structures that part of the sacrotuberous ligament was not secured tightly to compose pelvic diaphragm (2,11,12). A weakness of a muscle the external sphincter muscle. The external anal sphincter or fascia may cause a weakness of other structures composing muscle should be secured to the sacrotuberous ligament as the pelvic diaphragm. More than one type of perineal hernia well as the levator ani and coccygeus muscles in case that the can occur simultaneously in the weakened parts of the pelvic levator ani and coccygeus muscles are atrophic or the hernia diaphragm although perineal hernia would occur through the contents protrude into the perineal region not only between the weakest part of the pelvic diaphragm. coccygeus muscle and sacrotuberous ligament but also between Each type of perineal hernia has been reported with differ- the levator ani and coccygeus muscles. ent factors causing herniation including tenesmus (possibly Some technical and anatomic consideration in surgery may due to constipation) and congenital or acquired weakness of increase the likelihood of a successful surgery. When the suture the pelvic diaphragm (1,11,15). In Rochat’s report, the sciatic is engaged to the sacrotuberous ligament, care should be taken hernia was implicated with tenesmus created by sacculectomy to not place the suture around or through the sciatic nerve without no atrophy of pelvic musculature (15). The levator ani because of the proximity of the nerve to this ligament (13). muscle atrophy was associated with the more common dorsal When the origin of the internal obturator muscle is incised or caudal perineal hernia. In Dorn’s report, the sciatic hernia and elevated along the caudal border of the ischium, the fascia was reported in a three-year-old miniature poodle and was and periosteum should be included to provide greater holding considered congenital (6). Proposed etiologies currently accept- power on repairing aspect of perineal hernia. The retroper- ed for the levator ani muscle atrophy include neurogenic and itoneal fat can be partially amputated and then reduced. A hormonal pathways (3,10). Factors causing tenesmus or stran- blunt dissection may not be effective to provide anatomy of guria such as prostatomegaly and rectal disease are implicated the muscular pelvic diaphragm in case that the retroperitoneal as contributors to herniation (17,19). In the case reported here, fat is adherent to the perineal region severely. Fail to obtain it is impossible to determine what caused the sciatic hernia; anatomy of the muscular pelvic diaphragm can decrease the however, atrophy of the levator ani and coccygeus muscles likelihood of a successful surgery. may suggest that a neurogenic etiology take the blame for the Contralateral herniation is not common complication de- right perineal hernia since the dog was castrated. Factors caus- scribed after perineal hernia repair, accounting for 0 to 3.5% ing tenesmus or stranguria were not contributors to the right of dogs undergoing unilateral perineal herniorrhaphy (4,11,18). perineal hernia; however, the history of previous right perineal Although perineal herniation occurs unilaterally, the contralat- herniorrhaphy may have been contributory to the left perineal eral side of the pelvic diaphragm may also have possibility of hernia as well as neurogenic etiology. Irritation created by the perineal hernia because of the pelvic musculature weakening herniorrhaphy may have resulted in unobserved tenesmus. (5). In the case reported here, severe atrophy of the levator ani Choosing an appropriate technique for herniorrhaphy is and coccygeus muscles was observed during the right perineal very important to prevent perineal hernia recurrence, restore herniorrhaphy and the contralateral pelvic musculature weaken- normal defecation and urination, and minimize postoperative ing was observed during the left perineal herniorrhaphy as well. complications. In the left perineal hernia of the case reported here, the muscle flap technique using the modified internal Acknowledgements obturator muscle transposition was performed to close the ventral aspects of the sciatic and caudal perineal hernias This work was supported by the National Research Founda- because of better closure of the ventral aspect of sciatic and tion of Korea Grant funded by the Korean Government [NRF- caudal perineal hernias and the low recurrence rate and 2009-353-E00034]. minimal complications. 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개에서 좌골, 등쪽, 뒤쪽 회음탈장의 동시 발생 증례

윤헌영·정순욱1 건국대학교 수의과대학 수의외과학 교실, 수의과학 연구소

요약: 체중 1.8 kg 5년령 중성화 수컷 치와와 개가 오른쪽 회음부 팽대 평가를 위해 건국대학교 부속 동물병원에 내원하였다. 회음부 팽대 외에 다른 증상이 없었으며 신체 검사에서 환납성 회음탈장임을 확인 하였다. 회음 탈장 교 정을 위해 수정 된 전통 탈장 봉합술과 수정 된 내폐쇄근 변위 탈장 봉합술을 동시에 실시 하였다. 수술 한달 후 보 호자가 왼쪽 회음부 팽대를 보고하였고 수의사의 신체검사에서 왼쪽 회음탈장이 확인 되었다. 수술 중 좌골, 등쪽, 뒤 쪽 회음탈장의 동시 발생이 관찰 되었으며 회음 탈장 교정을 위해 위와 동일한 탈장 봉합술을 실시하였다. 정기 점진 은 수의사의 신체 검사 혹은 보호자와의 전화 통화를 통해 실시 되었으며 양측 수술 부위에서 수술과 관련한 합병 증 상이 없음을 확인하였다. 주요어 : 회음 탈장, 수정 된 내폐쇄근 변위 탈장 봉합술, 수정 된 전통 탈장 봉합술, 개