**2.2. The role of MISS**

Recent advances in surgical techniques and percutaneous instrument placement have led to the development of minimally invasive approaches for the treatment of spinal metastases; these result in less post-operative pain, shorter overall hospital stays, less intra-operative blood loss, and an earlier start of adjuvant therapy [2, 11–14].

The reported advantages of these techniques include smaller incisions, which limit wound complications, and the avoidance of back muscles detachment and retraction that causes postoperative pain and profuse bleeding, thus, reducing the need of intra or post-operative blood transfusion. These advantages are crucial for maintaining and improving the quality of life of cancer patients with short- or mid-term life expectancy [15–17].

MISS technique has the aim to perform (1) percutaneous insertion of pedicle screws and rods; (2) small exposure and detachment of the para-spinal muscles, to avoid their denerva‐ tion and devascularization; (3) a mini-open midline approach to decompress the spinal cord, reducing bleeding and post-operative pain.

Standard open techniques require the full exposure of the posterior elements of the involved segments, with complete exposure of facet joints, thus resulting in much more aggressive damage to the back muscles and soft tissues.

Our procedure is first based on the placement of purely percutaneous pedicle screws; using a double x-ray arch, a four-handed surgery was performed, in order to reduce the operation time and minimize the radiation exposure.

A mini-open median posterior approach to expose only spinous process and laminae of the involved segments is then performed. A laminotomy, without the removal of the spinous process, just in case it was not infiltrated, is performed; the posterior joints are not exposed and removed to reduce the muscle detachment and retraction (which produces an excessive bleeding).

The advantage of MISS techniques, in achieving an early better quality of life, seems to be related to their ability to reduce post-operative pain for both surgical-related and spinal metastasis-related components.

Criticism remains, regarding the reported difficulty of MISS to decompress enough spinal cord in case of spinal canal invasion; this persuasion is due to the erroneous conviction that the larger the surgical exposure, the better results achieved. On the contrary, in fact, MISS techniques permit an easy access to the spinal canal and complete spinal cord decompres‐ sion and roots if needed.

#### **2.3. Comparative study to traditional open surgery—materials and methods**

Two series of cancer patients, with a mBS 1 or 2, presenting acute myelopathy due to verte‐ bral thoracic metastases have been compared. The first group were composed of patients prospectively enrolled from May 2010 to December 2013 and treated with MISS procedures (MISS) (n=29); the second group was composed of retrospectively collected patients treated with a traditional open surgery (OS) (n=25). Patients with complete neurological deficit (ASIA A) for more than 24 hours and a mBS >2 were excluded from present study.

**2.2. The role of MISS**

424 Neurooncology - Newer Developments

loss, and an earlier start of adjuvant therapy [2, 11–14].

reducing bleeding and post-operative pain.

damage to the back muscles and soft tissues.

time and minimize the radiation exposure.

metastasis-related components.

sion and roots if needed.

bleeding).

cancer patients with short- or mid-term life expectancy [15–17].

Recent advances in surgical techniques and percutaneous instrument placement have led to the development of minimally invasive approaches for the treatment of spinal metastases; these result in less post-operative pain, shorter overall hospital stays, less intra-operative blood

The reported advantages of these techniques include smaller incisions, which limit wound complications, and the avoidance of back muscles detachment and retraction that causes postoperative pain and profuse bleeding, thus, reducing the need of intra or post-operative blood transfusion. These advantages are crucial for maintaining and improving the quality of life of

MISS technique has the aim to perform (1) percutaneous insertion of pedicle screws and rods; (2) small exposure and detachment of the para-spinal muscles, to avoid their denerva‐ tion and devascularization; (3) a mini-open midline approach to decompress the spinal cord,

Standard open techniques require the full exposure of the posterior elements of the involved segments, with complete exposure of facet joints, thus resulting in much more aggressive

Our procedure is first based on the placement of purely percutaneous pedicle screws; using a double x-ray arch, a four-handed surgery was performed, in order to reduce the operation

A mini-open median posterior approach to expose only spinous process and laminae of the involved segments is then performed. A laminotomy, without the removal of the spinous process, just in case it was not infiltrated, is performed; the posterior joints are not exposed and removed to reduce the muscle detachment and retraction (which produces an excessive

The advantage of MISS techniques, in achieving an early better quality of life, seems to be related to their ability to reduce post-operative pain for both surgical-related and spinal

Criticism remains, regarding the reported difficulty of MISS to decompress enough spinal cord in case of spinal canal invasion; this persuasion is due to the erroneous conviction that the larger the surgical exposure, the better results achieved. On the contrary, in fact, MISS techniques permit an easy access to the spinal canal and complete spinal cord decompres‐

Two series of cancer patients, with a mBS 1 or 2, presenting acute myelopathy due to verte‐ bral thoracic metastases have been compared. The first group were composed of patients prospectively enrolled from May 2010 to December 2013 and treated with MISS procedures (MISS) (n=29); the second group was composed of retrospectively collected patients treated

**2.3. Comparative study to traditional open surgery—materials and methods**

For both groups (n = 48, 32 women and 16 men, with a mean age of 54.6 yrs), the primitive tumors were: lung cancer (n = 17, 35.4%), breast cancer (n = 15, 31.2%), myeloma (n = 4, 8.3%), clear cell renal carcinoma (n = 3, 6.2%), melanoma (n = 3, 6.2%), prostate cancer (n = 2, 4%), ovarian cancer (n = 1, 2%), and thyroid cancer (n = 1, 2%) (**Table 1**).


**Table 1.** The clinical and oncological data of all the patients and divided by group.

Thirty two patients had one single level involved (66.6%), while 16 patients had a diseases extended to two or more segments (33.3%). In 19 patients (39.5%), the fracture involved a single column (OS: 52.6%, MISS: 31.0%), while two or three columns were substituted by cancer in 60.4% (**Table 1**).

The two groups were homogeneous, in terms of general and neurological conditions. All patients preoperatively presented an overall mean KPS of 56%, with 57.89 and 55.36% in the OS and MISS groups, respectively (p = 0.9); the mean overall mBS was 2.4 (2.6 and 2.3 in the OS and MISS group, respectively, p = 0.18) (**Table 1**). Pre- and post-operative ASIA scores for both groups are reported in **Table 2**.


Symptom scales b

Minimally Invasive Surgery for Treatment of Patients with Advanced Cancer and Thoraco-lumbar Spine Metastases http://dx.doi.org/10.5772/63125 427


**Table 2.** The pre-operative and post-operative neurological data (ASIA) and the quality of life data (EORTC QLQ-C30 and QLQ-BM22) of all the patients and divided by group.

The pre-operative neurological assessment showed a prevalence of ASIA D in both groups.

#### **2.4. Comparative study to traditional open surgery—results**

The two groups were homogeneous, in terms of general and neurological conditions. All patients preoperatively presented an overall mean KPS of 56%, with 57.89 and 55.36% in the OS and MISS groups, respectively (p = 0.9); the mean overall mBS was 2.4 (2.6 and 2.3 in the OS and MISS group, respectively, p = 0.18) (**Table 1**). Pre- and post-operative ASIA scores for

> A 3 3 6 B 2 4 6 C 6 9 15 D 8 13 21 E 0 0 0

Improved 12 (63%) 18 (62.0%) 30 (62.5%) Stable 6 (31%) 9 (31.0%) 15 (31.2%) Worse 1 (5%) 2 (6.7%) 3 (6.2%) P value 0.001 0.54

> Pre-op 16.00% 16.90% 16.60% Post-op 25.80% 32.10% 28.90%

> Pre-op 59.10% 55.10% 57.10% Post-op 72.60% 70.90% 71.70%

> Pre-op 33.00% 34.10% 33.50% Post-op 15.80% 15.10% 15.40%

> Pre-op 75.15% 72.90% 74.00% Post-op 79.80% 85.10% 82.45%

P value 0.01

P value 0.04

P value 0.009

P value 0.025

Functional scales b

Symptom scales b

**Group OPEN MISS Total P value**

both groups are reported in **Table 2**.

426 Neurooncology - Newer Developments

ASIA Pre-op

Post-op

EORTC QLQ-C30 QoL

Functional scales

Symptom scales

QLQ-BM22

Thirty patients (62.5%) showed an improvement of neurological status, while 15 patients were stable (31.2%), and only 3 patients (6.2%) worsened. No statistically significant differences in terms of neurological improvement were demonstrated between the two groups (p = 0.54). The neurological conditions for only three patients (7.1%) (1 from the OS group, and 2 from the MISS group) worsened; these results were not due to surgical-related complications, but to bad general conditions.


Surgical and hospitalization data are given in **Table 3**.

**Table 3.** Surgical and hospitalization data divided by group.

There were no serious peri-operative complications, in the MISS group; only one patient developed a post-operative urinary infection. In the OS group, 1 patient died on the 14th postoperative day, due to metastatic hepatic failure. The mean operation length was 3.2 h and 2.1 h respectively in the OS group and in the MISS group (p < 0.01).

The mean intra-operative blood loss was 900 mL in the OS group and 140 mL in the MISS group (p < 0.01). Twelve patients in the OS group required post-operative RBC transfusions, while no one in the MISS group required additional blood supply. The mean post-operative bed-rest time was 4 days with a mean length of hospitalization of 9.25 days in the OS group, while the mean post-operative bed-rest time was 2 days with a mean length of hospitaliza‐ tion of 7.3 days in the MISS group (p < 0.01).

Pre-operative scoring for quality of life (QoL) was homogeneous in both groups, according to the EORTC QLQ-C30 and EORTC QLQ-BM22 scales (**Table 2**). At follow-up, the analysis of EORTC QLQ-C30 questionnaire showed a mean overall improvement of 12.3% in QoL score (OS: 9.8%, MISS: 15.2%, p = 0.01), 14.6% in the functional scale score (OS: 13.5%, MISS: 15.8%, p = 0.04), and 18.1% for the symptoms scale score (OS: 17.2%, MISS 19%, p = 0.009). The evaluation of QLQ-BM22 scale showed a mean overall improvement at follow-up of 8.45% in the functional scale score (OS: 4.65%, MISS: 12.2%, p = 0.025), and 10.32% in symptoms scale score (OS: 8.45%, MISS: 12.2%, p = 0.001). The pre-operative VAS scores did not significantly differ between the groups (p > 0.015) (**Table 4**).


**Table 4.** The pre-operative and post-operative clinical data (VAS) and drug data (ANTALGIC) of all the patients and divided by group.

At follow-up, 31 patients (65%) showed an improvement of VAS score (OS: 53%, MISS: 72%), while 14 patients (29%) were stable (OS: 37%, MISS: 24%), and 3 patients (6%) worsened (OS: 10%, MISS: 4%) (p = 0.007).

In the pre-operative period, five patients received ad libitum administration of antalgic drugs, and 28 patients received it at follow-up (OS: 10, MISS: 18). 24 patients were pre-operatively administered NSAIDs, while 12 patients received NSAIDs at follow-up (OS: 4, MISS: 8). Nineteen patients were pre-operatively administered morphine, while eight patients were administered morphine at follow-up (OS: 5, MISS: 3) (p = 0.01).

#### **2.5. Illustrative case 1**

bed-rest time was 4 days with a mean length of hospitalization of 9.25 days in the OS group, while the mean post-operative bed-rest time was 2 days with a mean length of hospitaliza‐

Pre-operative scoring for quality of life (QoL) was homogeneous in both groups, according to the EORTC QLQ-C30 and EORTC QLQ-BM22 scales (**Table 2**). At follow-up, the analysis of EORTC QLQ-C30 questionnaire showed a mean overall improvement of 12.3% in QoL score (OS: 9.8%, MISS: 15.2%, p = 0.01), 14.6% in the functional scale score (OS: 13.5%, MISS: 15.8%, p = 0.04), and 18.1% for the symptoms scale score (OS: 17.2%, MISS 19%, p = 0.009). The evaluation of QLQ-BM22 scale showed a mean overall improvement at follow-up of 8.45% in the functional scale score (OS: 4.65%, MISS: 12.2%, p = 0.025), and 10.32% in symptoms scale score (OS: 8.45%, MISS: 12.2%, p = 0.001). The pre-operative VAS scores did not significantly

**Group OPEN MISS Total**

0–20 2 3 5 40 4 4 8 60 6 11 17 80 3 6 9 100 4 5 9

Improved 10 (53%) 21 (72%) 31 (65%) Stable 7 (37%) 7 (24%) 14 (29%) Worse 2 (10%) 1 (4%) 3 (6%)

Ad lib. 2 3 5 NSAID 10 14 24 Morphine 7 12 19

Ad lib. 10 18 28 NSAID 4 8 12 Morphine 5 3 8

P value 0.015

P value 0.01

tion of 7.3 days in the MISS group (p < 0.01).

428 Neurooncology - Newer Developments

differ between the groups (p > 0.015) (**Table 4**).

VAS Pre-op

Post-op

ANTALGIC Pre-op

Post-op

A 75-year-old with a two-year history of white cell renal carcinoma, already treated with chemo- and radio-therapy, presented with sudden leg weakness, hyper-reflexia, and urge-

**Figure 2.** Clinical case #1. Pre-operative MRI axial, CT axial and MRI sagittal scan (A, B and C) showed an osteolytic lesion which substituted the T12 body and its right pedicle, with initial invasion of the spinal canal. In the D and E images it is shown the postoperative CT scan in the axial and coronal plane which documented the percutaneous short fixation with transpedicular screws at T11, L1, and at the left pedicle of T12, followed by a mini-open access, centered at the level of T12, with a decompressive right laminotomy. Skin incisions in the F image.

incontinence (ASIA C, KPS 60, mBS 2), after a one-month history of severe thoracic spinal pain (VAS 90/100), unresponsive to common analgesics. Imaging showed a lesion which substituted the T12 body and its right pedicle, with initial invasion of the spinal canal. He then underwent a pure percutaneous short fixation with transpedicular screws at T11, L1, and at the left pedicle of T12, followed by a mini-open access, centered at the level of T12, with a decompressive laminotomy.

The patient was mobilized in the first post-operative day, with an almost complete resolu‐ tion of thoracic pain (VAS 20/100). Intraoperative blood loss was 200 cc, and RBC transfu‐ sion was not necessary. No opioids were administered in the post-operative period, and the patient was discharged on the fourth post-operative day. A post-operative CT scan showed the complete decompression of the spinal cord, with segmental fixation. At the follow-up, the patient presented a complete restoration of neurological deficit (ASIA E), and antalgic therapy with non-steroidal anti-inflammatory drugs (NSAID) was only administered ad libitum (**Figure 2**).

#### **2.6. Illustrative case 2**

**Figure 3.** Clinical case 2. Pre-operative MRI sagittal scan and coronal thoraco-lumbar X-ray (A and B images) showed diffuse spinal metastatic localizations with pathologic fractures of T9, T10 and T11, severe kyphosis and medullary compression in patient with a previous right partial T10 corpectomy with T9-T11 antero-lateral fixation. In the C and D images it is shown the postoperative CT scan 3D reconstruction which documented the percutaneous fixation with transpedicular screws at T7, T8, left pedicle of T9, L1 and L2, followed by a mini-open access, centered at the level of T10-T11, with a decompressive laminotomy and double cross-link. Skin incisions in the F image.

A 77-year-old woman, with a seven-year history of follicularthyroid cancer and previous lung andspine metastases that were treated with leftinferior pulmonary lobectomy andright partial T10 corpectomy with T9-T11 antero-lateral fixation, respectively, came to our attention, having a new onset of severe thoraco-lumbar pain (VAS 90/100) with leg weakness (ASIA C). The free interval of disease was three years, afterthe conclusion of adjuvant chemo- and radio-therapy. Imaging showed diffuse spinal metastatic localizations with pathologic fractures of T9, T10 and T11; a severe kyphosis of the dorsal spine was evident. MRI results also showed spinal cord compression at T10-T11 levels, due to extradural metastatic tissue and progressive kyphosis (ASIA C, KPS 60, mBS 2).

The patient underwent a pure percutaneous fixation by transpedicular screws at T7, T8, L1 and L2, while at T9 only on the left pedicle was screwed; a mini-open access, centered at the level of T10-T11, was performed with decompressive laminotomy and positioning of two cross-links. The patient was mobilized in the first post-operative day. Intraoperative blood loss was only 350 cc. No opioids were administered in the post-operative period, and the patient was discharged on the eighth post-operative day. A CT scan, performed at the discharge, showed the complete decompression of the spinal cord and the final fixation. At follow up, the neurological conditions improved (ASIA D), and opioids were stopped, in order to start antalgic therapy with NSAID (**Figure 3**).
