Identification and injury to the inferior hypogastric plexus in nerve-sparing radical hysterectomy

Waterjet dissection of the inferior hypogastric plexus (IHP) resulted in a more rapid return of normal urodynamics than blunt dissection (control group) in patients who received laparoscopic nerve-sparing radical hysterectomy (NSRH) in a randomized controlled study. However, the definite reasons for these results were unknown. This subgroup analysis compared the neural areas and impairment in the IHP uterine branches harvested during NSRH as an alternative to the IHP vesical branches between the waterjet and control groups. This study included samples from 30 eligible patients in each group of the trial NCT03020238. At least one specimen from each side of the IHP uterine branches was resected. The tissues were scanned, images were captured, and the neural component areas were calculated using the image segmentation method. Immunohistochemical staining was used to evaluate neural impairment. The control and waterjet groups had similar areas of whole tissues sent for evaluation. However, the control group had significantly fewer areas (median 272158 versus 200439 μm2, p = 0.044) and a lower percentage (median 4.9% versus 3.0%, p = 0.011) of neural tissues. No significant changes in immunohistochemical staining were found between the two groups. For patients with residual urine ≤100 and >100 ml at 14 days after NSRH (42 and 18 patients, respectively), there were significantly different percentages of neural tissues in the resected samples (p < 0.001). Hence, Due to the accurate identification of IHP during NSRH, the waterjet dissection technique achieved better urodynamic results.

Waterjet Dissection for Partial Nephrectomy Without Hilar Clamping in a Porcine Model

Hilar clamping is typically used in partial nephrectomy to control hemorrhage, which may damage the renal tissue under warm ischemia conditions. The purpose of this study was to evaluate waterjet technology in partial nephrectomy without renal hilar vascular control in a porcine model. Bilateral partial nephrectomy using waterjet was performed in 8 pigs (16 kidneys: 8 for wedge resections, 8 for pole resections). The operations were performed successfully in all animals. The mean dissection time was 30.6 ± 2.9 minutes for pole resections and 36.5 ± 3.5 minutes for wedge resections. The mean blood loss was 51.6 ± 11.7 mL for pole resections and 38.7 ± 9.2 mL for wedge resections. The novel waterjet technique provided precise and effective hydrodissection of the kidney, avoiding damage to the vascular structures or collecting system.

Waterjet Dissection of Peripheral Nerves: An Experimental Study of the Sciatic Nerve of Rats

ABSTRACT BACKGROUND: Although waterjet dissection has been well evaluated in intracranial pathologies, little is known of its qualities in peripheral nerve surgery. Theoretically, the precise dissection qualities could support the separation of nerves from adjacent tissues and improve the preservation of nerve integrity in peripheral nerve surgery. OBJECTIVE: To evaluate the potential of the new waterjet dissector in peripheral nerve surgery. METHODS: Waterjet dissection with pressures of 20 to 80 bar was applied on the sciatic nerves of 101 rats. The effect of waterjet dissection on the sciatic nerve was evaluated by clinical tests, neurophysiological examinations, and histopathological studies up to 12 weeks after surgery. RESULTS: With waterjet pressures up to 30 bar, the sciatic nerve was preserved in its integrity in all cases. Functional damaging was observed at pressures of 40 bar and higher. However, all but 1 rat in the 80 bar subgroup showed complete functional regeneration at 12 weeks after surgery. Histopathologically, small water bubbles were observed around the nerves. At 40 bar and higher, the sciatic nerves showed signs of direct nerve injury. However, all these animals showed nerve regeneration after 12 weeks, as demonstrated by histological studies. CONCLUSION: Sciatic nerves were preserved functionally and morphologically at pressures up to 30 bar. Between 40 and 80 bar, reliable functional and morphological nerve regeneration occurred. Waterjet pressures up to 30 bar might be applied safely under clinical conditions. This technique might be well suited to separate intact peripheral nerves from adjacent tumor or scar tissue. Further studies will have to show the clinical relevance of these dissection qualities.

Waterjet dissection in pediatric cranioplasty

Object Waterjet dissection has been shown to separate tissues of different resistance, with preservation of blood vessels. In cranioplasty, separation of subcutaneous tissue and dura mater is often difficult to achieve because the various tissue layers strongly adhere to each other after decompressive craniotomy. In the present study, the potential advantages and drawbacks of the waterjet technique in cranioplasty after craniectomy and duraplasty are addressed. Methods The waterjet effect on fresh human cadaveric dura mater specimens as well as on several dural repair patches was tested in vitro under standardized conditions, with waterjet pressures up to 80 bar. Subsequently, 8 pediatric patients (5 boys, 3 girls; mean age 9.9 years, range 1.2–16.7 years) who had been subjected to decompressive craniectomy (7 with duraplasty including bovine pericardium as a dural substitute, 1 without duraplasty in congenital craniosynostosis) underwent waterjet cranioplasty. The waterjet was used to separate the galea and the dura mater. The technique was applied tangentially between the dura and the galea, with different pressure levels up to 50 bar. Results In vitro, fresh cadaveric human dura mater as well as 2 different dural repair substitutes showed a very high resistance to waterjet dissection up to 80 bar. The human dura and the various substitutes were dissected only after long-lasting exposure to the waterjet. Human dura was perforated at pressures of 60 bar and higher. Bovine pericardium dural substitute was perforated at pressures of 55 bar and higher. Artificial nonabsorbable polyesterurethane dural substitute was dissected at pressures of 60 bar and higher. In the clinical setting, the waterjet was able to separate galea and dura with minimal bleeding. No blood transfusion was required. Dissection of scarred tissue was possible by a waterjet of 40 bar pressure. Tissue layers were stretched and separated by the waterjet dissection, and a very reliable hemostasis resulted. This resulted in an effective reduction of bleeding, with < 60 ml blood loss in 7 of the 8 cases. Neither a dural tear nor a perforation of any duraplasty occurred during operative preparation. There were no operative or postoperative complications. Conclusions The experimental and clinical data show that waterjet separation of dura mater, dural substitute, and galea can be performed with a high level of safety to avoid dural tears. The waterjet dissection stretches tissue layers, which results in a reliable hemostasis effect. This potentially results in an effective reduction of surgical blood loss, which should be the focus of further studies.

Waterjet dissection of the vestibulocochlear nerve: an experimental study

Object Waterjet dissection has been shown to protect intracerebral vessels, but no experience exists in applying this modality to the cranial nerves. To evaluate its potential, the authors examined waterjet dissection of the vestibulocochlear nerve in rats. Methods Lateral suboccipital craniectomy and microsurgical preparation of the vestibulocochlear nerve were performed in 42 rats. Water pressures of 2–10 bar were applied, and the effect was microscopically evaluated. Auditory brainstem responses (ABRs) were used to define nerve function compared with preoperative values and the healthy contralateral side. The final anatomical preparation documented the morphological and histological effects of waterjet pressure on the nerve. Results In using up to 6 bar, the cochlear nerve was preserved in all cases. Eight bar moderately damaged the nerve surface. A 10-bar jet markedly damaged or even completely dissected the nerve. Time course analysis of the ABR demonstrated complete functional nerve preservation up to 6 bar after 6 weeks in all rats. Waterjet dissection with 8 bar was associated with a 60% recovery of ABR. In the 10-bar group, no recovery was seen. Conclusions Microsurgical dissection of cranial nerves is possible using waterjet dissection while preserving both morphology and function. The aforementioned jet pressures are known to be effective in neurosurgical treatment of tumors. Thus, waterjet dissection may be useful in skull base surgery including dissection of cranial nerves from tumors. Further studies on this subject are encouraged.

The use of waterjet dissection in endoscopic neurosurgery

✓Waterjet dissection enables vessel preservation and a reduction in intraoperative blood loss. Because even minimal bleeding should be avoided during neuroendoscopy, the waterjet device may be a particularly valuable tool in such procedures. The authors used this instrument in experimental endoscopic procedures in 20 cadaveric porcine brains and clinically in four patients with obstructive hydrocephalus. A precise and accurate septostomy was achieved in all of the pig brains. In two patients the hydrocephalus was due to intraventricular hemorrhage, in one a posterior fossa tumor, and in one a cystic craniopharyngioma. In all patients the surgical view was kept clear with waterjet irrigation and suction. Using a pressure setting of 10 bars, the waterjet device successfully perforated the cyst wall of the craniopharyngioma in one patient and the floor of the third ventricle in three patients. The use of the waterjet device in selected endoscopic procedures appears safe, and may help reduce intraoperative bleeding. However, further studies are needed to confirm the utility of the waterjet tool in endoscopy.

Waterjet Dissection versus Ultrasonic Aspiration in Epilepsy Surgery

OBJECTIVE: Waterjet dissection is currently under close investigation in neurosurgery. Experimentally, precise brain parenchyma dissection with vessel preservation has been demonstrated. Clinically, the safety of the instrument has already been proved. However, precise data demonstrating that waterjet dissection indeed reduces surgical blood loss are still missing. METHODS: The authors applied the waterjet device in a prospective randomized study in comparison with the ultrasonic aspirator. Because there is little variability in the procedure, 30 patients with temporal lobe epilepsy receiving a tailored temporal lobe resection between December 1999 and October 2002 were selected for this study. Intraoperative vessel preservation, intraoperative blood loss, surgical complications, and epilepsy outcome were evaluated. All patients were followed at 3-month intervals. RESULTS: During surgery, both instruments were easy to handle. Only with the waterjet dissector, however, were even small intraparenchymal blood vessels preserved. Intraoperative blood loss was significantly reduced with the waterjet (mean, 70 ± 46 ml) compared with the ultrasonic aspirator (mean, 121 ± 48 ml). However, no difference in the necessity for blood transfusion occurred. No difference was observed with respect to operation time (238.6 ± 37.0 min with the waterjet, 247.5 ± 41.5 min with the ultrasonic aspirator), surgical complications, and outcome. CONCLUSION: The waterjet dissector enables a significant reduction of intraoperative blood loss in the investigated setting. However, further studies are needed to confirm these results with a larger number of patients. Studies also are needed to prove that the reduction of blood loss is of clinical relevance for the outcome of the patients.