Technical note on augmentation of diaphragmatic herniorrhaphy using the renal capsule

Abstract

This technical note describes a surgical technique for repairing a right dorsal crural diaphragmatic hernia and reports postoperative outcomes. Two client‐owned dogs were referred for a diaphragmatic hernia diagnosed via thoracic radiographs, suspected to be chronic and secondary to trauma. During surgery, a hernia was identified in the right dorsal crus of the diaphragm, and herniated contents were reduced. In Dog 1, the lateral aspect of the defect was closed using mattress sutures; however, insufficient local tissue precluded complete primary closure. To address this, the soft tissues lateral and dorsal to the caudal vena cava were sutured to the right renal capsule using mattress and cruciate sutures. The diaphragm was then anchored to the renal capsule laterally with mattress sutures to cover the residual defect. In Dog 2, the hernia was closed with cruciate sutures along the hernia edge, around the ribs, and into the deep fascia. Although most of the defect was closed, the right renal capsule was sutured over the dorsal hernia closure using cruciate sutures to seal small residual rents and augment the repair. Objective follow‐up periods were 134 days for Dog 1 and 27 weeks for Dog 2 (owner telephone calls at 13 and 9 months, respectively). No hernia recurrence or hernia‐ or surgery‐related clinical signs were observed. This study describes renal capsular‐augmented diaphragmatic herniorrhaphy for repairing right dorsal crus defects when local tissue is limited.

1. INTRODUCTION

Chronic diaphragmatic hernias can be difficult to close primarily due to insufficient local tissue for primary closure. Closure methods previously reported in dogs and cats include muscle flap (latissimus dorsi, transversus abdominis, or rectus abdominis), ¹ , ² , ³ omental pedicle flap, ⁴ porcine small intestinal submucosa graft, ⁵ , ⁶ polypropylene mesh, ⁷ and ventral advancement of the incised diaphragm. ⁸

Reconstruction of diaphragmatic hernias in the dorsal crura is particularly challenging without using prosthetic materials due to limited regional tissue availability. Although the use of an omental pedicle flap for repair of diaphragmatic rents is reported in a historical experimental study, ⁴ follow‐up outcomes in clinical canine patients are unavailable. To date, the use of the right kidney for hernia repair has not been described.

Nephropexy has been reported in humans and in a historical canine report for nephroptosis causing ureteral kinking, ⁹ , ¹⁰ , ¹¹ but remains uncommon. In cats, nephropexy is reported in contexts, including renal transplantation ¹² and subcutaneous ureteral bypass prior to the commercial availability of devices. ¹³ Building on these uses of the renal capsule for fixation, this technical note describes diaphragmatic herniorrhaphy using the renal capsule for augmentation and presents outcomes in two dogs with chronic right dorsal crus hernia.

2. MATERIALS AND METHODS

2.1. Clinical history and presentation

2.1.1. Dog 1

An 8‐year‐old male neutered Giant Schnauzer mix was referred for suspected chronic traumatic diaphragmatic hernia based on thoracic and abdominal radiographs. The dog had been hit by a car 21 months earlier and presented with acute collapse. A complete blood cell (CBC) count and biochemistry profile were unremarkable. A preoperative thoracic and abdominal computed tomography (CT) revealed a large right‐sided diaphragmatic hernia. A laparotomy and caudal thoracotomy using a sagittal saw through the caudalmost sternebrae were performed to reduce the herniated contents. A ventral right hernia was primarily closed using 2–0 polydioxanone (PDS, Ethicon) in a combination of simple continuous and interrupted patterns. Postoperative radiographs confirmed resolution. Four days postoperatively, the dog showed signs of nausea and vomiting/regurgitation. Repeat radiographs showed a focal herniation of a small intestinal segment at the level of the dorsal diaphragm, prompting revision surgery.

2.1.2. Dog 2

A 4‐year‐old male intact Boxer mix was referred for diaphragmatic hernia following thoracic and abdominal radiographs. The dog had a three‐week history of vomiting or regurgitation. No trauma had been reported in the previous 2 years, but chronic traumatic hernia was suspected based on his age, unknown prior history, and intraoperative findings showing adhesions of the hernia wall to the liver. A CBC and biochemistry profile were unremarkable, except for mild alanine transaminase activity elevation (245 U/L; reference range [RR]: 18–121) and mild electrolyte abnormalities (sodium: 137 mmol/L; RR: 142–152, potassium: 3.2; RR: 4.0–5.4 mmol/L, chloride: 71 mmol/L; RR: 108–119).

2.2. Surgical procedure

2.2.1. Dog 1

Following sedation and induction of anesthesia, the dog was positioned in dorsal recumbency and prepared aseptically. The previous midline abdominal incision was reopened. Upon entering the abdomen, a mild malodor and a moderate amount of abdominal fluid were noted; the fluid was sampled for culture and sensitivity testing. The previous right ventral hernia repair was intact. The liver appeared rounded with scarring. The descending duodenum and adjacent omentum were identified within the thorax, and a right dorsal diaphragmatic hernia was noted. The mesenteric lymph nodes were mildly enlarged; otherwise, the abdomen was unremarkable.

The herniated contents were manually reduced. A 5 cm, circular cicatricial defect was observed just to the right of the vena cava in the right crus. Due to insufficient local tissue for primary closure, the following procedures were performed to repair the remaining hernia:

1. The lateral defect margin was closed using 2–0 polydioxanone (PDS, Ethicon) suture in a mattress suture pattern.

2. The soft tissues and scar tissues located laterally and dorsally to the vena cava were sutured to the right renal capsule using 2–0 polydioxanone (PDS, Ethicon) suture with a taper‐point needle in a combination of mattress and cruciate suture patterns. Given the friability of renal parenchyma, only the renal capsule was used for fixation.

3. More laterally, the diaphragm itself was sutured to the renal capsule with 2–0 polydioxanone (PDS, Ethicon) suture in a mattress suture pattern. (Figure 1A)

FIGURE 1.

Intraoperative images showing nephropexy performed on Dog 1 (A) and Dog 2 (B). The diaphragm has been anchored to the renal capsule of the right kidney in a cruciate pattern. The cruciate sutures are shown by arrows in Dog 1 and by arrowheads in Dog 2.

A thoracostomy tube was placed and secured with 2–0 polypropylene (Prolene, Ethicon) suture. The abdomen was lavaged with 2 L of sterile saline. The linea alba was closed using a simple continuous pattern with 0 polydioxanone (PDS, Ethicon) suture. A pain‐diffusion catheter was placed and secured with 2–0 polypropylene (Prolene, Ethicon) suture. The remainder of the closure was performed routinely.

2.2.2. Dog 2

An exploratory midline laparotomy was performed. The falciform ligament was excised. A diaphragmatic hernia was present in the right dorsal diaphragmatic crus. The hernia contained the right middle and lateral liver lobes, the small intestines, the right kidney, half of the spleen, and half of the stomach. The radial defect was enlarged ventrally along the rib to facilitate the reduction of the hernia contents. The hernia defect walls adhered to the liver. Adhesions were broken down until the kidney and liver could be retracted. The hernia was closed with 0 polydioxanone (PDS, Ethicon) suture along the edge of the hernia, around the ribs, and into the deep fascia of the abdominal wall in a cruciate pattern. An 8 Fr red rubber catheter was inserted through the diaphragmatic hernia and aspirated until negative pressure was achieved, then removed. The defect was closed; however, the tissue integrity at some parts of the repair was questionable. To augment the repair, the right kidney capsule was sutured over the dorsal hernia closure with 2–0 polydioxanone (PDS, Ethicon) using a taper‐point needle in a cruciate pattern. (Figure 1B) The omentum was placed over the surgical site. Air was evacuated from the thorax with a red rubber feeding tube to reestablish negative pressure. The closure matched Dog 1.

3. RESULTS

3.1. Dog 1

The dog recovered uneventfully and was discharged 3 days postoperatively. Bacterial culture was negative. Follow‐up radiographs taken on days 3, 10, and 134, along with a CT scan on day 44, revealed no recurrence of diaphragmatic herniation in the right crus. No pleural effusion or pneumothorax was identified on the CT scan.

The CT scan revealed two significant anatomical findings relevant to the repair of the right dorsal crural hernia:

1. A small, persistent rent located on the dorsal aspect of the right diaphragmatic crus at the level of the caudal vena cava. (Figure 2) The kidney offered partial blockage of the hernia. While this blockage was incomplete medially, the caudal vena cava was positioned directly ventral to the rent, providing some degree of containment. Consequently, there was no evidence of herniation.

2. Mild cranial displacement of the caudal portion of the right crus of the diaphragm, apposed to the mid and cranial portions of the right kidney. (Figure 3) Additionally, moderate focal ventral deviation of the caudal vena cava has been observed at the caval foramen, alongside mild dilation of the caudal vena cava in the cranial thorax. This ventral deviation may be attributed to positional changes associated with nephropexy, coupled with dilation of the hepatic and post‐hepatic segments of the caudal vena cava.

FIGURE 2.

Computed tomography of Dog 1 performed 44 days post‐surgery. The identified rent was measured at its longest point: 27.8 mm in the transverse view (A), 26 mm in the coronal view, and 25.6 mm in the sagittal view (C).

FIGURE 3.

Computed tomography performed before the initial surgery (A) and 44 days post‐surgery (B) in Dog 1. Note the mild cranial shift of the diaphragm alongside the right kidney.

Although the most recent radiography performed on day 134 suggested a potential pleuroperitoneal hernia indicated by increased opacity in the right ventral thorax where the initial surgery was performed, the dog remained clinically normal.

The owner was contacted by phone 13 months postoperatively and reported that the dog remained clinically well with normal appetite, water intake, activity level, respiration, and no gastrointestinal or respiratory concerns.

3.2. Dog 2

The dog recovered from anesthesia uneventfully. Although a subjectively mild to moderate pleural effusion was observed on ultrasound, the dog was clinically stable and discharged 2 days postoperatively. Follow‐up thoracic radiographs at 9 weeks showed no evidence of recurrent diaphragmatic hernia. (Figure 4) On the ventrodorsal view, the crura were asymmetric, with cranial displacement of the left crus compared to the right and an undulating border. Additional findings included a possible pulmonary mass in the caudal subsegment of the left cranial lung lobe, a diffuse bronchial pattern, and a mediastinal shift to the right with the left lung lobes overinflated. Repeat thoracic radiographs at 23 weeks showed no change in these findings and no evidence of recurrent diaphragmatic hernia. A focal thoracic ultrasound performed 27 weeks after surgery revealed a 3‐cm, well‐defined, smooth, hypoechoic pulmonary mass at the level of the left fifth intercostal space. Ultrasound‐guided fine‐needle aspiration yielded a sample with low cellularity and moderate hemodilution, with no evidence of neoplastic cells. The dog remained clinically normal, 9 months postoperatively with no owner concerns about general health or gastrointestinal or respiratory signs.

FIGURE 4.

Thoracic radiographs taken 9 weeks after surgery for Dog 2. (A) Ventrodorsal view. (B) Right lateral view. The blue arrows in (A) and (B) indicate an incidentally discovered possible pulmonary or pleural mass.

4. DISCUSSION

This technical note describes diaphragmatic hernia repair in the right crus, augmented by the renal capsule, and reports good short‐term outcomes without recurrence of herniation or abnormal postoperative clinical signs.

In Dog 1, the CT scan revealed a persistent small rent, incompletely covered by the kidney, but effectively sealed, with no evidence of herniation, pleural effusion, or pneumothorax, along with a normal respiratory clinical status. The functional seal appeared to maintain negative intrathoracic pressure, as evidenced by the parietal pleural contacts with the lungs. ¹⁴ The positional changes in the caudal vena cava and the diaphragm, likely resulting from the nephropexy, were clinically insignificant. These anatomical shifts may vary based on kidney fixation sites. Although nephropexy is a documented technique, it is prudent to monitor for possible long‐term renal effects resulting from the anatomical shifts.

In Dog 2, thoracic radiographs taken 9 weeks post‐surgery showed cranial shift of the left crus, opposite the right nephropexy, possibly due to contralateral phrenic nerve dysfunction from previous trauma. Given the signalment, history, absence of radiographic progression, and low cellularity on cytology, the pulmonary mass in the caudal segment of the left cranial lung lobe was considered most likely secondary to fibrosis or another benign process. The rightward shift of the mediastinum may be secondary to atelectasis from recumbency, although partial collapse or consolidation of the right middle lung lobe is also a possibility. This finding could indicate a change in intrathoracic pressure on the right side, resulting from small, invisible rents. However, the atelectasis may also reflect chronic changes resulting from previous trauma.

In conclusion, renal capsular‐augmented diaphragmatic herniorrhaphy may be an alternative when a large chronic right‐sided dorsal defect precludes primary closure; it is straightforward, minimally invasive, without incurring additional costs or requiring synthetic materials.

AUTHOR CONTRIBUTIONS

Kimura S, BVSc, MSc: Assisted in surgery, collected data, and drafted and edited the manuscript. Boston S, DVM, DVSc, DACVS (Small Animal), ACVS Founding Fellow of Surgical Oncology, ACVS Founding Fellow of Oral & Maxillofacial Surgery (Small Animal): Conceptualized the surgical technique, performed the surgery, and edited the manuscript. Mehrkens LR, DVM, DACVS (Small Animal): Performed surgery and edited the manuscript. Biskup JJ, DVM, DACVS (Small Animal): Performed surgery and edited the manuscript.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflict of interest related to this report.