Navigated Ultrasonic Osteotomy to Aid in En Bloc Chordoma Resection via Spondylectomy

Surgical Strategy and Application of Robotic-Assisted Benign Sacral Neurogenic Tumor Resection

BACKGROUND

Robotic surgery may be advantageous in neurogenic sacral tumor resection but only a few studies reported robotic-assisted neurogenic sacral tumor resection.

OBJECTIVE

To propose a new surgical strategy for robotic-assisted benign sacral neurogenic tumor resection and introduce the ultrasonic osteotomy surgical system in robotic surgery.

METHODS

Twelve patients who had robotic-assisted primary benign sacral neurogenic tumor resection between May 2015 and March 2021 were included. Our surgical strategy divides tumors into 4 types. Type I: Presacral tumors with diameter <10 cm. Type II: Narrow-base tumors involving the sacrum with diameter <10 cm. Type III: Broad-base tumors involving the sacrum with diameter <10 cm. Type IV: Tumors involving sacral nerve roots ≥2 levels and/or with diameter ≥10 cm.

RESULTS

Five type I, 5 type II, and 1 type III patients underwent tumor resection via an anterior approach, and 1 type IV patient via a combined approach. The median operation time, blood loss, and postoperative hospital stay of type I and II were much less than those of type IV. The ultrasonic osteotomy surgical system facilitated osteotomy in 2 type II and 1 type III patients. Eleven patients had total resections, and 1 type III patient had a partial resection. During the follow-up period of 7.9 to 70.9 months (median: 28.5 months), no local recurrences or deaths were noted.

CONCLUSION

With the largest single-center series to our knowledge, this surgical strategy helped to guide robotic-assisted benign sacral neurogenic tumor resection. The ultrasonic osteotomy surgical system was effective for type II and III.

Progress in Excision Methods of Bone Materials

Bone resection is a common technique in modern surgery, which can be divided into contact (such as mechanical osteotomy and ultrasonic osteotomy) and non-contact (such as laser osteotomy). Irrespective of the excision method, it causes processing damage to natural bone material, thus affecting bone healing. To reduce the machining damage in bone resection, different machining variables (cutting fluid temperature, feed rate, rotational speed, and ultrasonic frequency) were considered to explore the selection of various cutting conditions. This paper reviews the excision of natural bone materials including mechanical osteotomy, laser osteotomy, and ultrasonic osteotomy, especially traditional drilling and ultrasonic cutting, which represent the traditional and prospective methods of bone excision technology, respectively. Finally, the differences between methods are emphasized and the future trends in osteotomy technology and condition control during osteotomy are analyzed.

Ultrasonic spine surgery for every thoracic disc herniation: a 43-patient case series and technical note demonstrating safety and efficacy using a partial transpedicular thoracic discectomy with ultrasonic aspiration and ultrasound guidance

OBJECTIVE

Thoracic disc herniations (TDHs) are a challenging pathology. A variety of surgical techniques have been used to achieve spinal cord decompression. This series elucidates the versatility, efficacy, and safety of the partial transpedicular approach with the use of intraoperative ultrasound and ultrasonic aspiration for resection of TDHs of various sizes, locations, and consistencies. This technique can be deployed to safely remove all TDHs.

METHODS

A retrospective review was performed of patients who underwent a thoracic discectomy via the partial transpedicular approach between January 2014 and December 2020 by a single surgeon. Variables reviewed included demographics, perioperative imaging, and functional outcome scores.

RESULTS

A total of 43 patients (53.5% female) underwent 54 discectomies. The most common presenting symptoms were myelopathy (86%), motor weakness (72%), and sensory deficit (65%) with a symptom duration of 10.4 ± 11.6 months. A total of 21 (38.9%) discs were fully calcified on imaging and 15 (27.8%) were partially calcified. A total of 36 (66.7%) were giant TDHs (> 40% canal compromise). The average operative time was 197.2 ± 77.1 minutes with an average blood loss of 238.8 ± 250 ml. Six patients required ICU stays. Hospital length of stay was 4.40 ± 3.4 days. Of patients with follow-up MRI, 38 of 40 (95%) disc levels demonstrated < 20% residual disc. Postoperative Frankel scores (> 3 months) were maintained or improved for all patients, with 28 (65.1%) patients having an increase of 1 grade or more on their Frankel score. Six (14%) patients required repeat surgery, 2 of which were due to reherniation, 2 were from adjacent-level herniation, and 2 others were from wound problems. Patients with calcified TDHs had similar improvement in Frankel grade compared to patients without calcified TDH. Additionally, improvement in intraoperative neuromonitoring was associated with a greater improvement in Frankel grade.

CONCLUSIONS

The authors demonstrate a minimally disruptive, posterior approach that uses intraoperative ultrasound and ultrasonic aspiration with excellent outcomes and a complication profile similar to or better than other reported case series. This posterior approach is a valuable complement to the spine surgeon's arsenal for the confident tackling of all TDHs.

Case Series of Ultrasonic Navigated Osteotomy for the Treatment of Spinal Chordomas

BACKGROUND

Chordomas present challenges for en bloc surgical resection, which optimally reduces local recurrence and increases patient survival. Navigated ultrasonic osteotomy, also known as piezosurgery, provides a distinct advantage for achieving negative margins after en bloc resection.

METHODS

Eight consecutive patients with chordomas (2 cervical, 3 lumbar, and 3 sacral) treated with navigated ultrasonic osteotomy to achieve en bloc resection were identified from our institutional spine tumor database (2016-2019) and retrospectively reviewed.

RESULTS

En bloc resection, with negative margins, was achieved in all cases. Two patients (25%) were women, and mean age at surgery was 44 ± 11 years. Median estimated blood loss was 1000 mL (interquartile range: 263-1500 mL). Median length of hospital stay was 10 days (interquartile range: 3-19.5 days). Two patients required a revision procedure. Two patients had complications requiring readmission within the 30-day postoperative window. Mean duration of follow-up for the cohort was 900 ± 554 days.

CONCLUSIONS

Navigated ultrasonic osteotomy is an effective surgical technique to achieve en bloc resection of chordomas with negative margins and disease-free survival. To date, this represents the first reported cohort of patients undergoing the procedure as described here. Future studies should include larger sample sizes for more robust clinical outcome data to further elucidate the benefits of piezosurgery for obtaining en bloc chordoma resection.